Intraoperative ultrasound combined with MRI for evaluating float back and enlargement of the spinal cord after cervical laminoplasty in the management of degenerative cervical myelopathy

Intraoperative ultrasound combined with MRI for evaluating float back and enlargement of the spinal cord after cervical laminoplasty in the management of degenerative cervical myelopathy | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Intraoperative ultrasound combined with MRI for evaluating float back and enlargement of the spinal cord after cervical laminoplasty in the management of degenerative cervical myelopathy Jiachun Li, Zhenxiang Chen, Hanzhong Liu, Shenghui Huang, Peng Cui, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3385824/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Spinal cord floating and enlargement can develop after cervical laminectomy and laminoplasty, it determines whether completely decompress the cord. To assess the relationship between immediate float back and enlargement of the spinal cord after decompression and subsequent recovery of spinal cord function. Methods The parameters associated with float back and enlargement of the spinal cord in Intraoperative ultrasound (IOUS) and preoperative MRI were investigated. Spinal cord function recovery was also investigated as measured by the mJOA score at the one-year follow-up. Results The average preoperative mJOA score was 10.24 ± 2.59, the postoperative mJOA score was 14.51 ± 2.32, and improvements in mJOA score were achieved with an average recovery rate of 64.29%±27.70%. The immediate float back distance after decompression (1.01 ± 0.49 mm) was positively correlated with the one-year follow-up mJOA score (P < 0.01, r = 0.68) and the recovery rate of the mJOA score (P < 0.01, r = 0.72). The immediate enlargement of the spinal cord (1.39 ± 0.84 mm) was positively correlated with the one-year follow-up mJOA score (P < 0.01, r = 0.64) and the recovery rate of the mJOA score (P < 0.01, r = 0.71). Immediate enlargement of the front side of the spinal cord (1.39 ± 0.59 mm) was positively correlated with the one-year follow-up mJOA score (P < 0.01, r = 0.74) and the recovery rate of the mJOA score (P < 0.01, r = 0.73). Interestingly, only enlargement of the front side of the spinal cord was positively correlated with the preoperative mJOA score (P < 0.05, r = 0.36). Conclusions The extent of immediate spinal cord float back, and enlargement after decompression in French-door cervical laminoplasty can be evaluated using preoperative MRI combined with IOUS, and these indications help predict the clinical outcome after French-door expansive laminoplasty. intraoperative ultrasound Japanese Orthopaedic Association score degenerative cervical myelopathy French-door expansive laminoplasty magnetic resonance imaging Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Background Degenerative cervical myelopathy (DCM), previously referred to as cervical spondylosis myelopathy[ 1 , 2 ], is a spinal condition that results in chronic, nontraumatic compression of the cervical spinal cord. It is the leading cause of spinal cord dysfunction among adults worldwide[ 3 , 4 ]. This clinicopathologic entity encompasses osteoarthritic degeneration and ligamentous aberrations[ 5 ]. Spinal cord compression results in progressive neurological decline and affects the quality of life[ 6 ]. Many articles have been published annually on the clinical presentation of DCM. The Japanese Orthopaedic Association (JOA) score, created in 1975, has been used to assess neurological changes in DCM patients in Japan. In detail, the JOA score encompasses measures of bodily motor and sensory functions, urinary autonomic function, and activities of daily living. The modified JOA (mJOA) score was established in 1994, and the revisions involved more detailed examinations, including examinations of the shoulder and elbow[ 7 – 9 ]. In addition to clinical neurological assessments, radiological evaluations are also critical. The diagnostic workup often includes X-ray, computed tomography (CT), magnetic resonance imaging (MRI), and myelography examinations[ 10 ]. MRI has been widely applied in diagnosing diseases of the spine and its contents[ 11 ]. It helps evaluate the spinal canal diameter, spinal cord, intervertebral discs, and vertebral ligaments[ 12 ]. Signal changes on T2-weighted MRI at the level of spinal compression are often increased in patients with DCM. These changes can represent edema, inflammation, ischemia, myelomalacia, or gliosis[ 13 ]. Alternatively, Nakashima et al. described a method measuring the anteroposterior (AP) length of disc migration into the canal by drawing a line between the posterior aspect of the adjacent vertebra in the region of interest (ROI) and measuring the extent of disc migration from that line[ 12 , 13 ]. Although DCM is determined clinically, the diagnosis requires confirmation by imaging, and MRI is the preferred modality. Another radiological evaluation tool that has gradually been applied is intraoperative spinal ultrasound (IOUS) technology. Due to noninvasiveness, lack of radiation, ability to acquire images in multiple planes, low examination costs, and conveniences, such as bedside operation and easy operation even by non-radiologists, IOUS can be used to dynamically assess the spinal cord in real-time, which cannot be achieved by MRI [ 14 – 16 ]. However, its uses mainly focus on the spinal cord and dural pulsations, the subarachnoid space ventral to the cervical spinal cord, and the decompression status[ 17 , 18 ]. A previous study showed that IOUS was more helpful than postoperative MRI for predicting the clinical outcomes of expansive cervical laminoplasty[ 19 ]. Due to lordotic cervical, laminoplasty affords indirect anterior decompression by allowing the spinal cord to migrate dorsally[ 20 , 21 ]. Also, spinal canal expansion and spinal cord decompression produce cord enlargement[ 22 ]. The cord floats back, and enlargement determines whether completely decompress the cord, and several studies have used CT myelography and MRI to assess the relationship between the changes in the spinal cord and the clinical results[ 23 ]. However, some changes immediately occurred and could not be observed by CT myelography and MRI. The extent of immediate spinal cord float back, and enlargement after decompression during French-door cervical laminoplasty can be evaluated by preoperative MRI combined with IOUS. Few studies have assessed the relationship between immediate spinal cord changes and clinical results besides a survey from our team[ 22 ]. The purpose of the study was to determine the relationship between the recovery of spinal cord function and immediate spinal cord float back and enlargement—as reflected in measurements of the front side of the spinal cord and the anteroposterior diameter of the entire spinal cord in the sagittal plane—after decompression during French-door cervical laminoplasty. Methods The Seventh Affiliated Hospital Ethics Committee of Sun Yat-sen University approved the study. All procedures carried out by ethical standards, and informed consent was obtained from all patients. Patients and neurological outcomes In this retrospective study, 46 patients with multilevel DCM (≥ 3) were consecutively enrolled from October 2018 to October 2021 in the Seventh Affiliated Hospital of Sun Yat-sen University. Patients with a history of thoracic or lumbar disorders, trauma, infection, tumors, rheumatoid arthritis, or previous cervical surgery were excluded. Ultimately, 36 patients who underwent French-door cervical laminoplasty and were followed up for at least one year were included in this study. Posterior French-door expansive laminoplasty from C3-C7 was performed in all cases. Neurological outcomes were evaluated by the modified JOA (mJOA) scoring system from preoperation to one-year postoperation. The recovery rate (RR) of the mJOA score was calculated using the following formula[ 22 ]. Recovery rate of mJOA score = (Postoperative mJOA score – Preoperative mJOA score)/(17 – Preoperative mJOA score) × 100% Surgical procedure French-door cervical laminoplasty was applied in all patients. All surgical procedures were performed in the prone position and with slight flexion. The operative levels ranged from C3 to C7. The posterior laminae were exposed through a mid-dorsal approach, according to the method for modified Kurokawa's double-door laminoplasty[ 24 ]. After the split spinous process was opened double-door and the bilaterally split spinous process was fixed, the surgical area was filled with saline, allowing usage as an acoustic window. The surgeon manipulated the probe to obtain visualization of different sections of the spinal cord (Fig. 1 ). The surgeon and the sonographer could observe the sonographic features of the spinal cord at the same time, and both in charge of this procedure, with one Spinal Surgeon attending all operations. The sonographer was responsible for image quality control and guided image acquisition. The whole ultrasonic examination time was controlled to be within 20 minutes. Radiologic assessments Radiologic assessments included MRI and IOUS. The preoperative spinal cord condition was evaluated by MRI (GE Medical Systems, Milwaukee, WI, USA), which one surgeon and radiologist performed together. All patients underwent IOUS during the operation. After opening the spinous process and bilateral laminae, IOUS was performed using a 14 MHz high-frequency linear array probe to visualize the spinal cord with an acoustic window created with saline. The probe was approximately 15 mm wide (Mindray, Mindray Biomedical Electronics Co., Ltd., Shenzhen, China). Images of the spinal cord showing maximal sagittal and midsagittal compression were obtained on both sagittal T2-weighted MRI and longitudinal IOUS. The parameters were measured preoperatively in sagittal T2-weighted MRI images and then longitudinally on IOUS after decompression. The specific method was described by Hiroaki Nakashima et al. in 2015[ 12 ]. The parameters measured were the hollow diameter in the largest area of the spinal cord before (HDB) and after (HDA) decompression (Fig. 2 A, B), the spinal cord diameter in the maximum compression area before (CDB) and (CDA) decompression (Fig. 2 C, D), and the midsagittal space anterior to the cord before (SACB) and after decompression (SACA) (Fig. 2 E, F). Then immediate front side of spinal cord enlargement (IFSE, HDB-HDA), immediate total spinal cord enlargement after French-door laminoplasty decompression (ITSE, CDA-CDB), and immediate spinal cord float back (ISCF, SACA-SACB) measurements were compared before and after decompression. Finally, the correlations of these data with the mJOA score (preoperation mJOA score, one-year follow-up mJOA score, recovery rate of mJOA score) were evaluated. Statistical analysis SPSS version 20 software (SPSS, Chicago, IL, USA) was used for all statistical analyses. All values are expressed as the mean ± standard deviation. Measurements of immediate spinal cord float back (ISCF, SACA-SACB), the immediate front side of spinal cord enlargement (IFSE, HDB-HDA), and the immediate total of spinal cord enlargement after decompression (ITSE, CDA-CDB) were calculated before and after French-door laminoplasty decompression. (Fig. 2 A, B). According to achieved improvement scores, patients were divided into two groups: Group 1 completed improvements of more than 3 points; Group 2 achieved improvements of less than or equal to 3 points. Moreover, patients were classified into two groups according to preoperative mJOA scores: Group A had preoperative mJOA scores greater than 10, and Group B had preoperative mJOA scores less than or equal to 10. Compare ISCF, IFSE, and ITSE between groups 1 and 2. Meanwhile, compare IFSE between groups A and B. Then Spearman correlation analysis was used to analyze the correlations of these data with the mJOA score (preoperation mJOA score, one-year follow-up mJOA score). Differences between corresponding groups were compared using One-Way ANOVA. Results Thirty-six patients with DCM underwent surgery, and IOUS with posterior French-door expansive laminoplasty, including 26 males and ten females, had an average age of 54.1 ± 8.8 years (range 35–78 years). The overall duration of symptoms averaged 31 ± 15.05 months. No patient loss to follow-up or die at one-year after the operation. Among those patients, intraoperative blood loss was 137±58 ml, IOUS examination was 16.2±3.7 minutes, and the total operating time was 179.4±43.8 minutes (Table 1). After the operation, the neurological outcomes were assessed by the scoring system. The average preoperative mJOA score was 10.24±2.59, the postoperative mJOA score was 14.51±2.32, and improvements in mJOA scores were achieved with an average recovery rate of 64.29%±27.70%. Compared to the preoperative values, the average of achieved improvement scores in mJOA was 4.28±0.46, and the distribution of segments is shown in Table 2. Patients were divided into two groups according to achieved improvement scores: patients in group 1 achieved improvements of more than 3 points, and 18 patients were enrolled thereby; patients in group 2 achieved improvements of less than or equal to 3 points, and 18 patients were enrolled thereby (Table 4). Meanwhile, patients have been classified into two groups according to preoperative mJOA scores: patients in group A had preoperative mJOA scores greater than 10, and 18 patients were enrolled thereby; patients in group B had preoperative mJOA scores less than or equal to 10, and 18 patients were enrolled thereby (Table 5). The mean spinal cord diameter in the maximum compression area before French-door laminoplasty decompression (CDB) in MRI was 3.98±0.91 mm; the value in IOUS after decompression (CDA) was 5.36±1.11 mm. The largest hollow diameter in morphological changes before decompression (HDB) was 2.99±1.06 mm; after decompression (HDA), it was 1.60±0.71 mm. The space anterior to the cord in the midsagittal plane before decompression (SACB) was 5.08±1.11 mm, and after decompression (SACA), it was 6.08±1.28 mm. Regarding immediate measurements, the spinal cord float back (ISCF, SACA-SACB) was 1.01±0.49 mm, the front side of the spinal cord enlargement (IFSE, HDB-HDA) was 1.39±0.59 mm, and the total spinal cord enlargement after decompression (ITSE, CDA-CDB) was 1.39±0.84 mm (Table 3). The immediately measured float back distance after decompression (ISCF, SACA-SACB) had a positive correlation with the one-year follow-up mJOA score (P<0.01, r=0.68) and a positive correlation with the recovery rate of the mJOA score (P<0.01, r=0.72) (Fig. 3 A, B). Immediately measured enlargement of the front side of the spinal cord (IFSE, HDB-HDA) had a positive correlation with the one-year follow-up mJOA score (P<0.01, r=0.74) and a positive correlation with the recovery rate of the mJOA score (P<0.01, r=0.73) (Fig. 3 C, D). Immediately measured enlargement of the entire spinal cord (ITSE, CDA-CDB) had a positive correlation with the one-year follow-up mJOA score (P<0.01, r=0.64) and a positive correlation with the recovery rate of the mJOA score (P<0.01, r=0.71) (Fig. 3 E, F). Interestingly, immediate enlargement of the front side of the spinal cord (IFSE, HDB-HDA) was positively correlated with the preoperative mJOA score (P<0.05, r=0.36) (Fig. 3 G). Regarding group 1, in which patients achieved improvements greater than three scores, values of ISCF, IFSE, and ITSE were all higher than those in group 2, in which patients achieved improvements less than or equal to 3 scores (P<0.05) (table 4, Fig. 4 A, B, C). Group A included patients with preoperative mJOA scores higher than 10, and Group B included patients with preoperative mJOA scores less than or equal to 10 (P<0.05) (Table 5, Fig. 5). Discussion French-door laminoplasty offers symmetrical decompression by opening the spinous processes' midline and hinging both laminae. Bilateral troughs are created on each lamina, thus creating a "French door" that allows the float-back spinal cord to move posteriorly[ 25 – 27 ]. The spinal cord floats back, and enlargement can develop after surgery. Several studies have assessed the relationship between CT myelography and MRI changes in the spinal cord and clinical results[ 23 ]. Morphological changes in the spinal cord after laminoplasty by CT myelography. The sagittal diameter of the spinal cord increased, and the rearward movement of the spinal cord in the supine position was more significant in the middle of the cervical spine[ 23 ]. However, some changes occurred immediately and could not be observed by CT myelography and MRI. The extent of immediate spinal cord float back, and enlargement after French-door cervical laminoplasty decompression can be evaluated by preoperative MRI combined with IOUS. This study aimed to assess the relationship between immediate spinal cord float back and enlargement (including the front side of the spinal cord and the entire spinal cord) after French-door laminoplasty decompression and recovery of spinal cord function. In our research, preliminary data suggest that the extent of immediate spinal cord floating back, front side spinal cord enlargement, and total spinal cord enlargement after decompression during French-door laminoplasty have a positive correlation with the one-year follow-up mJOA score and the recovery rate of the mJOA score. Furthermore, we classified those patients who improved mJOA scores into two groups: 18 patients achieved scores greater than 3 in group 1, and 18 patients achieved scores less than or equal to 3 in group 2. In group 1, the values of ISCF, IFSE, and ITSE were all higher than those in group 2 (P < 0.05). From this, it can be concluded that within limits, more float back, more enlargement of the front side of the spinal cord, and total spinal cord enlargement may be associated with a higher one-year follow-up mJOA score and recovery rate of mJOA score. Based on this, improving the immediate float back and enlargement of the spinal cord may further improve the postoperative recovery of spinal cord function. On the other hand, immediate enlargement of the front side of the spinal cord has a definite correlation with the one-year follow-up mJOA score and the recovery rate of the mJOA score and a solid correlation with the preoperative mJOA score. Then we classified patients into two groups according to preoperative mJOA scores: Group A patients had preoperative mJOA scores greater than 10, and 18 patients were enrolled thereby; group B patients had preoperative mJOA scores less than or equal to 10, and 18 patients were enrolled thereby. IFSE values in group A were higher than in group B (P < 0.05). These findings indicate that the front side of the spinal cord accrued compensation due to the plasticity of the spinal cord[ 28 ], and this observation helps predict preoperative and postoperative spinal cord function. In our previous study, the ratio of compressed to non-compressed areas of the spinal cord was measured to compare the overall expansion of the spinal cord[ 22 ]. However, in posterior open-door surgery, the posterior is fully opened, and the recovery of anterior spinal cord compression is more critical. At the same time, in another study of our previous study, the gray value in the anterior of the spinal cord was more relevant to the recovery of the patient's motor function[ 29 ]. Due to the higher proportion of motor function in the JOA, the rally in front of the spinal cord is more related to the recovery of JOA. For DCM, complete posterior decompression can be achieved after posterior open-door laminectomy. Still, there are some differences in postoperative neurological function, which cannot wholly predict. However, even with complete decompression of the spinal cord and no anterior contact of the spinal cord, postoperative neurological recovery varies in different patients. There may be three reasons for this: First, the degree of spinal cord compression before an operation differs. Second, the time of spinal cord compression is different, and third, the location of spinal cord compression is different. Based on the above three reasons, it can be speculated that even if the exact decompression is performed, the various states of the spinal cord itself may lead to different spinal cord functions after decompression. This study evaluated the posterior shift of the spinal cord, the expansion of the whole spinal cord, and the growth of the anterior edge of the spinal cord, which partly reflected the state of the spinal cord itself. It could predict the recovery of neurological function to a certain extent. If the recovery prediction was not reasonable, we could consider further measures such as durotomy, spinal cord pia mater decompression, timely nutritional nerve, and functional exercise. Another study demonstrated spinal cord morphology and dynamics during cervical laminoplasty for DCM were classified into four grades. Restoration of the anterior subarachnoid space was considered a significant factor of neurologic improvement following posterior cervical decompression surgery[ 18 ]. However, a previous study failed to find a substantial correlation between Clinical recovery and the subarachnoid space width in IOUS and MRI[ 30 ]. This conclusion may be due to differences between categorical and continuous variables, different operating methods, a small set of samples, or only some degree of change will be associated with postoperative spinal cord function, and other reasons to produce this different result. Of course, there are some limitations to the present study:1. The study’s sample size was small, and the follow-up period for postoperative evaluation of the JOA score (i.e., one year) was short. 2. The related data were measured on sagittal images in IOUS and MRI; however, those sagittal images were not in strict accordance. 3. Ultrasound procedures were performed by surgeons, which might impact the quality of ultrasound images. 4. The extent of immediate float back of the spinal cord and enlargement after French-door cervical laminoplasty decompression was evaluated by preoperative MRI combined with IOUS. “Immediate” generally means less than 30 minutes; however, this method does not strictly represent “immediately.” 5. IOUS was performed with the patient in the prone position, while MRI was performed with the patient in the supine position; this difference could be a source of some errors in parameter measurement. Conclusions In conclusion, IOUS helps evaluate spinal cord status in real-time after decompression. The extent of immediate float back of the spinal cord and enlargement after decompression in French-door cervical laminoplasty can be assessed by preoperative MRI combined with IOUS. These indications help predict the clinical outcome after French-door expansive laminoplasty. Abbreviations IOUS intraoperative ultrasound MRI magnetic resonance imaging DCM Degenerative cervical myelopathy JOA Japanese Orthopaedic Association mJOA modified JOA CT computed tomography AP anteroposterior ROI the region of interest RR recovery rate DR dorsal roots VR ventral roots CSF cerebrospinal fluid HDB the hollow diameter in the largest area of the spinal cord before decompression HDA the hollow diameter in the largest area of the spinal cord after decompression CDB the spinal cord diameter in the maximum compression area before decompression CDA the spinal cord diameter in the maximum compression area after decompression SACB the midsagittal space anterior to the cord before decompression SACA the midsagittal space anterior to the cord after decompression IFSE Then immediate front side of spinal cord enlargement (HDB-HDA) ITSE immediate total spinal cord enlargement after French-door laminoplasty decompression (CDA-CDB) ISCF immediate spinal cord float back (SACA-SACB) Declarations Ethics approval and consent to participate This study was approved by The Seventh Affiliated Hospital of Sun Yat-sen University Ethics Committee. Written informed consent was obtained from all participants included in the study. Consent for publication All participants, gave written and informed consent for publication for all personal or clinical details along with any identifying images to be published in this study. Availability of data and materials The datasets used or analyzed during the current study are available from the corresponding author on reasonable request. Competing interests All authors declare that they have no competing interest. Funding This study was funded by Foundation of Shenzhen Committee for Science and Technology Innovation (JCYJ20220530154800002), The Seventh Affiliated Hospital of SYSU, Clinical Research Fund (ZSQYLCKYJJ202018), Sanming Project of Medicine in Shenzhen (SZSM201911002), Zhejiang Provincial Natural Science Foundation of China (LQ20H170001), Joint Funds of the Zhejiang Provincial Natural Science Foundation of China (LBY21H170001), Basic Research Project of Shenzhen Science and Technology Innovation Commission (JCYJ20210324122807021), and Guangxi Key Laboratory of Basic and Translational Research of Bone and Joint Degenerative Disease (21-220-06). Authors' contributions JL, FW, and WL conceived of the presented idea. JL, JW and WL performed the ultrasound testing, carried out the radiological measurements, and interpretation of data. JL, HL and JW carried out the clinical data collection. JL, ZC and HL analyzed the results and wrote the manuscript. HL, SH and PC performed the calculations and statistical data. All authors discussed the results and contributed to the final version of the manuscript. All authors reviewed the manuscript. Acknowledgements Not applicable. Authors' information 1 Department of Orthopaedics, The Seventh Affiliated Hospital of Sun Yat-Sen University, #628 Zhenyuan Road, Shenzhen, Guangdong 518100, China 2 Department of Orthopaedics, South China Hospital of Shenzhen University, #1 Fuxin Road, Shenzhen, Guangdong 518111, China 3 Department of Ultrasound, The Seventh Affiliated Hospital of Sun Yat-Sen University, #628 Zhenyuan Road, Shenzhen, Guangdong 518100, China References Fehlings MG, Tetreault LA, Riew KD, Middleton JW, Aarabi B, Arnold PM, Brodke DS, Burns AS, Carette S, Chen R, et al. A Clinical Practice Guideline for the Management of Patients With Degenerative Cervical Myelopathy: Recommendations for Patients With Mild, Moderate, and Severe Disease and Nonmyelopathic Patients With Evidence of Cord Compression. Glob Spine J. 2017;7(3 Suppl):70S–83S. Davies BM, Mowforth OD, Smith EK, Kotter MR. Degenerative cervical myelopathy. Bmj-Brit Med J. 2018;360:k186. Houten JK, Shahsavarani S, Verma RB. The Natural History of Degenerative Cervical Myelopathy. Clin Spine Surg. 2022;35(10):396–402. Badhiwala JH, Wilson JR. The Natural History of Degenerative Cervical Myelopathy. Neurosurg Clin N Am. 2018;29(1):21–32. Oh T, Lafage R, Lafage V, Protopsaltis T, Challier V, Shaffrey C, Kim HJ, Arnold P, Chapman J, Schwab F, et al. Comparing Quality of Life in Cervical Spondylotic Myelopathy with Other Chronic Debilitating Diseases Using the Short Form Survey 36-Health Survey. World Neurosurg. 2017;106:699–706. Furlan JC, Catharine CB. Psychometric analysis and critical appraisal of the original, revised, and modified versions of the Japanese Orthopaedic Association score in the assessment of patients with cervical spondylotic myelopathy. Neurosurg Focus. 2016;40(6):E6. Badhiwala JH, Ahuja CS, Akbar MA, Witiw CD, Nassiri F, Furlan JC, Curt A, Wilson JR, Fehlings MG. Degenerative cervical myelopathy - update and future directions. Nat Rev Neurol. 2020;16(2):108–24. Sangondimath G, Mallepally AR, Marathe N, Mak KC, Suman S. Degenerative cervical myelopathy: Recent updates and future directions. J Clin Orthop Trauma. 2020;11(5):822–9. Shedid D, Benzel EC. Cervical spondylosis anatomy: pathophysiology and biomechanics. Neurosurgery. 2007;60(1 Supp1 1):7–S13. Takahashi M, Yamashita Y, Sakamoto Y, Kojima R. Chronic cervical cord compression: clinical significance of increased signal intensity on MR images. Radiology. 1989;173(1):219–24. Arnasson O, Carlsson CA, Pellettieri L. Surgical and conservative treatment of cervical spondylotic radiculopathy and myelopathy. Acta Neurochir. 1987;84(1–2):48–53. Nakashima H, Yukawa Y, Suda K, Yamagata M, Ueta T, Kato F. Cervical Disc Protrusion Correlates With the Severity of Cervical Disc Degeneration: A Cross-Sectional Study of 1211 Relatively Healthy Volunteers. Spine. 2015;40(13):E774–9. Nouri A, Martin AR, Mikulis D, Fehlings MG. Magnetic resonance imaging assessment of degenerative cervical myelopathy: a review of structural changes and measurement techniques. Neurosurg Focus. 2016;40(6):E5. Sions JM, Teyhen DS, Hicks GE. Criterion Validity of Ultrasound Imaging: Assessment of Multifidi Cross-Sectional Area in Older Adults With and Without Chronic Low Back Pain. J Geriatr Phys Ther. 2017;40(2):74–9. Ghamkhar L, Emami M, Mohseni-Bandpei MA, Behtash H. Application of rehabilitative ultrasound in the assessment of low back pain: a literature review. J Bodyw Mov Ther. 2011;15(4):465–77. Liu W, Li J, Zhou X, Chen N, Ouyang H, Xu Z, Zhu Y. Dynamic evaluation of the contractile function of lumbodorsal muscles during locust pose in yoga by real-time ultrasound. Bmc Sports Sci Med R. 2021;13(1):87. Tat J, Tat J, Yoon S, Yee A, Larouche J. Intraoperative Ultrasound in Spine Decompression Surgery: A Systematic Review. Spine. 2022;47(2):E73–E85. Mihara H, Kondo S, Takeguchi H, Kohno M, Hachiya M. Spinal cord morphology and dynamics during cervical laminoplasty: evaluation with intraoperative sonography. Spine. 2007;32(21):2306–9. Naruse T, Yanase M, Takahashi H, Horie Y, Ito M, Imaizumi T, Oguri K, Matsuyama Y. Prediction of clinical results of laminoplasty for cervical myelopathy focusing on spinal cord motion in intraoperative ultrasonography and postoperative magnetic resonance imaging. Spine. 2009;34(24):2634–41. Weinberg DS, Rhee JM. Cervical laminoplasty: indication, technique, complications. J Spine Surg. 2020;6(1):290–301. Cho SK, Kim JS, Overley SC, Merrill RK. Cervical Laminoplasty: Indications, Surgical Considerations, and Clinical Outcomes. J Am Acad Orthop Sur. 2018;26(7):e142–52. Chen G, Wei F, Shi L, Li J, Wang X, Wang M, Wu H, Xu Z, Liu X, Liu S. Inadequate spinal cord expansion in intraoperative ultrasound after decompression may predict neurological recovery of degenerative cervical myelopathy. Eur Radiol. 2021;31(11):8478–87. Aita I, Hayashi K, Wadano Y, Yabuki T. Posterior movement and enlargement of the spinal cord after cervical laminoplasty. J Bone Joint Surg Br. 1998;80(1):33–7. Wang L, Wei F, Liu S, Wan Y, Chen N, Cui S, Zhong R, Huang Y. Can Modified Kurokawa's Double-Door Laminoplasty Reduce the Incidence of Axial Symptoms at Long-term Follow-up? A Prospective Study of 152 Patients With Cervical Spondylotic Myelopathy. J Spinal Disord Tech. 2015;28(4):E186–93. Wiguna I, Magetsari R, Noor Z, Suyitno S, Nindrea RD. Comparative Effectiveness and Functional Outcome of Open-Door versus French-Door Laminoplasty for Multilevel Cervical Myelopathy: A Meta-Analysis. Open Access Maced J Med Sci. 2019;7(19):3348–52. Heller JG, Raich AL, Dettori JR, Riew KD. Comparative effectiveness of different types of cervical laminoplasty. Evid Based Spine Care J. 2013;4(2):105–15. Atkins D, Best D, Briss PA, Eccles M, Falck-Ytter Y, Flottorp S, Guyatt GH, Harbour RT, Haugh MC, Henry D, et al. Grading quality of evidence and strength of recommendations. Bmj-Brit Med J. 2004;328(7454):1490. Nouri A, Montejo J, Sun X, Virojanapa J, Kolb LE, Abbed KM, Cheng JS. Cervical Cord-Canal Mismatch: A New Method for Identifying Predisposition to Spinal Cord Injury. World Neurosurg. 2017;108:112–7. Chen G, Wei F, Li J, Shi L, Zhang W, Wang X, Xu Z, Liu X, Zou X, Liu S. Intensity of Intraoperative Spinal Cord Hyperechogenicity as a Novel Potential Predictive Indicator of Neurological Recovery for Degenerative Cervical Myelopathy. Korean J Radiol. 2021;22(7):1163–71. Biczok A, Fuetsch M, Siller S, Patzig M, Tonn JC, Zausinger S. Intraoperative ultrasonography in laminectomy for degenerative cervical spondylotic myelopathy: a clinical and radiological evaluation. Acta Neurochir. 2022;164(7):1873–81. Tables Table 1. Details of the patients Indicator Results Cases (number) 36 Sex (male/female) 26/10 Age at surgery, years 54.1 ± 8.8 Symptom durations, months 31 ± 15.05 Intraoperative blood loss, ml 137±58 IOUS examination time, minutes 16.2±3.7 Operating time, minutes 179.4±43.8 Table 2. Distribution of segments and mean ISCF, ITSE, and IFSE. Number Mean ISCF Mean ITSE Mean IFSE C3/4 5 0.93±0.46 mm 1.31±0.74 mm 1.26±0.47 mm C4/5 10 0.98±0.48 mm 1.37±0.87 mm 1.37±0.53 mm C5/6 13 1.08±0.52 mm 1.45±0.90 mm 1.44±0.66 mm C6/7 8 1.00±0.47 mm 1.35±0.78 mm 1.40±0.61 mm Total 36 1.01±0.49 mm 1.39±0.84 mm 1.39±0.59 mm Table 3. Mean CDB, CDA, ITSE, HDB, HDA, IFSE, SACB, SACA, and ISCF. Spinal cord diameter Hollow diameter Space anterior to the cord Before decompressed 3.98±0.91 mm (CDB) 2.99±1.06 mm (HDB) 5.08±1.11 mm (SACB) After decompressed 5.36±1.11 mm (CDA) 1.60±0.71 mm (HDA) 6.08±1.28 mm (SACA) Change 1.39±0.84 mm (ITSE) 1.39±0.59 mm (IFSE) 1.01±0.49 mm (ISCF) Table 4. Two groups achieved improved scores and detailed data of ISCF, IFSE, and ITSE in group 1 and group 2. Group n ISCF IFSE ITSE 1 18 1.24±0.39 mm 1.66±0.45 mm 1.78±0.68 mm 2 18 0.79±0.47 mm 1.12±0.59 mm 1.00±0.82 mm 36 P＜0.05 P＜0.05 P＜0.05 Table 5. According to preoperative mJOA scores, two groups detailed data of IFSE in groups A and B. Group n IFSE A 18 1.67±0.55 mm B 18 1.11±0.49 mm 36 P＜0.05 Additional Declarations No competing interests reported. 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Also discoverable on Platform About In Review Editorial Policies Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3385824","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":237085028,"identity":"739e8bb9-a52b-48a0-841d-99999ebbe99a","order_by":0,"name":"Jiachun Li","email":"","orcid":"","institution":"The Seventh Affiliated Hospital of Sun Yat-sen University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Jiachun","middleName":"","lastName":"Li","suffix":""},{"id":237085029,"identity":"dfd82aa4-e72b-4757-a8b1-bcb7631bba28","order_by":1,"name":"Zhenxiang Chen","email":"","orcid":"","institution":"The Seventh Affiliated Hospital of Sun Yat-sen University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Zhenxiang","middleName":"","lastName":"Chen","suffix":""},{"id":237085030,"identity":"19e2fa6b-481c-4c8b-9117-662b286f4e0e","order_by":2,"name":"Hanzhong Liu","email":"","orcid":"","institution":"The Seventh Affiliated Hospital of Sun Yat-sen University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Hanzhong","middleName":"","lastName":"Liu","suffix":""},{"id":237085031,"identity":"96a0c0ee-61f3-4df3-92f7-a25cd7aa950a","order_by":3,"name":"Shenghui Huang","email":"","orcid":"","institution":"South China Hospital of Shenzhen University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Shenghui","middleName":"","lastName":"Huang","suffix":""},{"id":237085032,"identity":"63f04e67-62cb-4196-8e2d-6523b7c57504","order_by":4,"name":"Peng Cui","email":"","orcid":"","institution":"South China Hospital of Shenzhen University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Peng","middleName":"","lastName":"Cui","suffix":""},{"id":237085033,"identity":"e3b51c18-bfa3-4056-8d32-e53d684ea981","order_by":5,"name":"Junming Wan","email":"","orcid":"","institution":"The Seventh Affiliated Hospital of Sun Yat-sen University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Junming","middleName":"","lastName":"Wan","suffix":""},{"id":237085034,"identity":"080f8ee6-3a47-4524-8464-4c1c98a6bd04","order_by":6,"name":"Fuxin Wei","email":"","orcid":"","institution":"The Seventh Affiliated Hospital of Sun Yat-sen University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Fuxin","middleName":"","lastName":"Wei","suffix":""},{"id":237085035,"identity":"f1c9fc06-2ec8-451a-b6f3-a095214de814","order_by":7,"name":"Wenfen Liu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/klEQVRIiWNgGAWjYBACPmYgUVFhI8fAwNh4ACYqgU8LG0jLmTNpxkAtDURqARFn2w4lNgBpIrWw85hJHGA7kL62/TDQlj+H7Q0OMB+8zcNgl4fbYSAtPHdyt51JbDjA2HY4ccMBtmRrHobkYnxabn+QeJa77QBIS8PhBIMDPGbSPAwHwE7FpeXGAYPD6WbnH8Icxv+NCC0JhxPMbgBtYWA7zLjhAA8bAS1s5T8OHEgz3HYDaEtiW3rizMNsxpZzDJJxauHnP7zZ4OA/G3mz8+kPH3z4Y23Pd7z54Y03FXY4taCCBIZmBgZQ5DIYEKUeDOqIVzoKRsEoGAUjBgAApABeEGnyvlgAAAAASUVORK5CYII=","orcid":"","institution":"The Seventh Affiliated Hospital of Sun Yat-sen University","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Wenfen","middleName":"","lastName":"Liu","suffix":""}],"badges":[],"createdAt":"2023-09-25 16:59:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3385824/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3385824/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":44205890,"identity":"acc525aa-0f32-45db-95b5-c3441b433065","added_by":"auto","created_at":"2023-10-06 20:18:32","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":451057,"visible":true,"origin":"","legend":"\u003cp\u003eA. Sagittal IOUS plane after French-door laminoplasty. Fig. 1B. Cross-sectional IOUS plane at C5 after French-door laminoplasty. The orange arrows indicate the spinal dura mater, the yellow arrows indicate the pia mater, the grey arrows indicate the spinal cord central echo complex, the green arrows indicate the cervical disc, the red arrows indicate the cervical vertebral body, and the blue arrows show the opened spinous process. The hollow red arrows indicate the subarachnoid space. Both the dorsal roots (DR) and ventral roots (VR) are visible and surrounded by cerebrospinal fluid (CSF).\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3385824/v1/870430fdbefbb007c9bbd294.jpg"},{"id":44205892,"identity":"07840d8c-92ce-49ae-8ef2-0fdc52618aef","added_by":"auto","created_at":"2023-10-06 20:18:32","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":9441535,"visible":true,"origin":"","legend":"\u003cp\u003eA, B: The hollow diameter in morphological changes in the most significant area after (HDA, Fig. 2 A) and before (HDB, Fig. 2 B) the spinal cord was decompressed: a posterior aspect line was drawn between the two distal ends of the hollow and used as a baseline (the red line), and the distance from this line to the deepest point of the hollow (the yellow line) was measured. Measurements of immediate front side of spinal cord enlargement (IFSE, HDB-HDA) were compared before and after decompression; Fig. 2C, D: The anteroposterior (AP) distance of the spinal cord in the maximum compression area after (CDA, Fig. 2C) and before (CDB, Fig. 2D) decompression: the minimum AP distance of the spine cord in the area of maximum compression (the yellow line) was measured after (CDA) and before (CDB) decompression, and measurements of immediate total of spinal cord enlargement after decompression (ITSE, CDA-CDB) were compared before and after decompression; Fig. 2E, F: The space anterior to the cord in the midsagittal plane after (SACA, Fig. 2E) and before (SACB, Fig. 2F) decompression: a posterior aspect line was made from the rostral vertebral body to the caudal vertebral body (including 3 points, i.e., the rostral vertebral body, the midpoint, and the caudal vertebral body) and used as a baseline (the orange line), with a minimum AP distance from the line to the area of spinal compression (the yellow line), and measurements of immediate spinal cord float back (ISCF, SACA-SACB) were compared before and after decompression.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-3385824/v1/a067a8611cb2f152ff7ea0b5.png"},{"id":44207477,"identity":"4ea3a6b1-09ea-42ca-a30b-486a7cd0a934","added_by":"auto","created_at":"2023-10-06 20:26:32","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":859488,"visible":true,"origin":"","legend":"\u003cp\u003eThere was a positive correlation between the immediate spinal cord float back distance (ISCF, SACA-SACB) after decompression and the mJOA score at the one-year follow-up (Fig. 3 A, P\u0026lt;0.01, r=0.68), the recovery rate of mJOA score (Fig. 3 B, P\u0026lt;0.01, r=0.72). There was a positive correlation between the immediate front side spinal cord enlargement (IFSE, HDB-HDA) and the mJOA score at the one-year follow-up (Fig. 3 C, P\u0026lt;0.01, r=0.74), Correlation with a recovery rate of mJOA score (Fig. 3 D, P\u0026lt;0.01, r=0.73). There was a positive correlation between the immediate total spinal cord enlargement after decompression (ITSE, CDA-CDB) and the mJOA score at the one-year follow-up (Fig. 3 E, P\u0026lt;0.01, r=0.64), Correlation with a recovery rate of mJOA score (Fig. 3 F, P\u0026lt;0.01, r=0.71). Fig. 3G. There was a positive correlation between the immediate front side spinal cord enlargement (IFSE, HDB-HDA) and preoperative mJOA score (Fig. 3 G. P\u0026lt;0.05, r=0.36).\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-3385824/v1/22545e498cf9e60bd1500949.png"},{"id":44205891,"identity":"2ad02c7a-a2a6-41d2-a37d-367a430cada6","added_by":"auto","created_at":"2023-10-06 20:18:32","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":423676,"visible":true,"origin":"","legend":"\u003cp\u003eTwo groups, according to achieved improvement scores, the difference in ISCF, IFSE, and ITSE between group 1 and group 2. The ISCF in group 1 was higher than that in group 2 (P\u0026lt;0.05, Fig. 4A). In observed values of IFSE and ITSE, group 1 was higher than group 2 as well (P\u0026lt;0.05, Fig. 4 B, C).\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-3385824/v1/fbe978c19b9a2649d3d18b1a.png"},{"id":44207476,"identity":"2370c43f-c1f9-4824-aff1-3c47481a7037","added_by":"auto","created_at":"2023-10-06 20:26:32","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":91110,"visible":true,"origin":"","legend":"\u003cp\u003eTwo groups according to preoperative mJOA scores, the difference in IFSE values between group A and B. In ISCF value, group A was higher than group B (P\u0026lt;0.05, Fig. 5).\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-3385824/v1/f34b1847291890a79d62c9e9.jpg"},{"id":56102167,"identity":"5a57b3d7-c663-4207-911d-4d73854d8b12","added_by":"auto","created_at":"2024-05-08 14:50:25","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2022337,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3385824/v1/c00b23ae-504e-4dd7-85d5-4b3d5b34c3c7.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Intraoperative ultrasound combined with MRI for evaluating float back and enlargement of the spinal cord after cervical laminoplasty in the management of degenerative cervical myelopathy","fulltext":[{"header":"Background","content":"\u003cp\u003eDegenerative cervical myelopathy (DCM), previously referred to as cervical spondylosis myelopathy[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], is a spinal condition that results in chronic, nontraumatic compression of the cervical spinal cord. It is the leading cause of spinal cord dysfunction among adults worldwide[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. This clinicopathologic entity encompasses osteoarthritic degeneration and ligamentous aberrations[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Spinal cord compression results in progressive neurological decline and affects the quality of life[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Many articles have been published annually on the clinical presentation of DCM. The Japanese Orthopaedic Association (JOA) score, created in 1975, has been used to assess neurological changes in DCM patients in Japan. In detail, the JOA score encompasses measures of bodily motor and sensory functions, urinary autonomic function, and activities of daily living. The modified JOA (mJOA) score was established in 1994, and the revisions involved more detailed examinations, including examinations of the shoulder and elbow[\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn addition to clinical neurological assessments, radiological evaluations are also critical. The diagnostic workup often includes X-ray, computed tomography (CT), magnetic resonance imaging (MRI), and myelography examinations[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. MRI has been widely applied in diagnosing diseases of the spine and its contents[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. It helps evaluate the spinal canal diameter, spinal cord, intervertebral discs, and vertebral ligaments[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Signal changes on T2-weighted MRI at the level of spinal compression are often increased in patients with DCM. These changes can represent edema, inflammation, ischemia, myelomalacia, or gliosis[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Alternatively, Nakashima et al. described a method measuring the anteroposterior (AP) length of disc migration into the canal by drawing a line between the posterior aspect of the adjacent vertebra in the region of interest (ROI) and measuring the extent of disc migration from that line[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Although DCM is determined clinically, the diagnosis requires confirmation by imaging, and MRI is the preferred modality.\u003c/p\u003e \u003cp\u003eAnother radiological evaluation tool that has gradually been applied is intraoperative spinal ultrasound (IOUS) technology. Due to noninvasiveness, lack of radiation, ability to acquire images in multiple planes, low examination costs, and conveniences, such as bedside operation and easy operation even by non-radiologists, IOUS can be used to dynamically assess the spinal cord in real-time, which cannot be achieved by MRI [\u003cspan additionalcitationids=\"CR15\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. However, its uses mainly focus on the spinal cord and dural pulsations, the subarachnoid space ventral to the cervical spinal cord, and the decompression status[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. A previous study showed that IOUS was more helpful than postoperative MRI for predicting the clinical outcomes of expansive cervical laminoplasty[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDue to lordotic cervical, laminoplasty affords indirect anterior decompression by allowing the spinal cord to migrate dorsally[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Also, spinal canal expansion and spinal cord decompression produce cord enlargement[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The cord floats back, and enlargement determines whether completely decompress the cord, and several studies have used CT myelography and MRI to assess the relationship between the changes in the spinal cord and the clinical results[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. However, some changes immediately occurred and could not be observed by CT myelography and MRI. The extent of immediate spinal cord float back, and enlargement after decompression during French-door cervical laminoplasty can be evaluated by preoperative MRI combined with IOUS. Few studies have assessed the relationship between immediate spinal cord changes and clinical results besides a survey from our team[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The purpose of the study was to determine the relationship between the recovery of spinal cord function and immediate spinal cord float back and enlargement\u0026mdash;as reflected in measurements of the front side of the spinal cord and the anteroposterior diameter of the entire spinal cord in the sagittal plane\u0026mdash;after decompression during French-door cervical laminoplasty.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e The Seventh Affiliated Hospital Ethics Committee of Sun Yat-sen University approved the study. All procedures carried out by ethical standards, and informed consent was obtained from all patients.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatients and neurological outcomes\u003c/h2\u003e \u003cp\u003eIn this retrospective study, 46 patients with multilevel DCM (\u0026ge;\u0026thinsp;3) were consecutively enrolled from October 2018 to October 2021 in the Seventh Affiliated Hospital of Sun Yat-sen University. Patients with a history of thoracic or lumbar disorders, trauma, infection, tumors, rheumatoid arthritis, or previous cervical surgery were excluded. Ultimately, 36 patients who underwent French-door cervical laminoplasty and were followed up for at least one year were included in this study. Posterior French-door expansive laminoplasty from C3-C7 was performed in all cases.\u003c/p\u003e \u003cp\u003eNeurological outcomes were evaluated by the modified JOA (mJOA) scoring system from preoperation to one-year postoperation. The recovery rate (RR) of the mJOA score was calculated using the following formula[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cem\u003eRecovery rate of mJOA score = (Postoperative mJOA score \u0026ndash; Preoperative mJOA score)/(17 \u0026ndash; Preoperative mJOA score) \u0026times; 100%\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eSurgical procedure\u003c/h2\u003e \u003cp\u003eFrench-door cervical laminoplasty was applied in all patients. All surgical procedures were performed in the prone position and with slight flexion. The operative levels ranged from C3 to C7. The posterior laminae were exposed through a mid-dorsal approach, according to the method for modified Kurokawa's double-door laminoplasty[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAfter the split spinous process was opened double-door and the bilaterally split spinous process was fixed, the surgical area was filled with saline, allowing usage as an acoustic window. The surgeon manipulated the probe to obtain visualization of different sections of the spinal cord (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The surgeon and the sonographer could observe the sonographic features of the spinal cord at the same time, and both in charge of this procedure, with one Spinal Surgeon attending all operations. The sonographer was responsible for image quality control and guided image acquisition. The whole ultrasonic examination time was controlled to be within 20 minutes.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eRadiologic assessments\u003c/h2\u003e \u003cp\u003eRadiologic assessments included MRI and IOUS. The preoperative spinal cord condition was evaluated by MRI (GE Medical Systems, Milwaukee, WI, USA), which one surgeon and radiologist performed together. All patients underwent IOUS during the operation. After opening the spinous process and bilateral laminae, IOUS was performed using a 14 MHz high-frequency linear array probe to visualize the spinal cord with an acoustic window created with saline. The probe was approximately 15 mm wide (Mindray, Mindray Biomedical Electronics Co., Ltd., Shenzhen, China). Images of the spinal cord showing maximal sagittal and midsagittal compression were obtained on both sagittal T2-weighted MRI and longitudinal IOUS.\u003c/p\u003e \u003cp\u003eThe parameters were measured preoperatively in sagittal T2-weighted MRI images and then longitudinally on IOUS after decompression. The specific method was described by Hiroaki Nakashima et al. in 2015[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe parameters measured were the hollow diameter in the largest area of the spinal cord before (HDB) and after (HDA) decompression (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA, B), the spinal cord diameter in the maximum compression area before (CDB) and (CDA) decompression (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC, D), and the midsagittal space anterior to the cord before (SACB) and after decompression (SACA) (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eE, F). Then immediate front side of spinal cord enlargement (IFSE, HDB-HDA), immediate total spinal cord enlargement after French-door laminoplasty decompression (ITSE, CDA-CDB), and immediate spinal cord float back (ISCF, SACA-SACB) measurements were compared before and after decompression.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFinally, the correlations of these data with the mJOA score (preoperation mJOA score, one-year follow-up mJOA score, recovery rate of mJOA score) were evaluated.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eSPSS version 20 software (SPSS, Chicago, IL, USA) was used for all statistical analyses. All values are expressed as the mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation.\u003c/p\u003e \u003cp\u003eMeasurements of immediate spinal cord float back (ISCF, SACA-SACB), the immediate front side of spinal cord enlargement (IFSE, HDB-HDA), and the immediate total of spinal cord enlargement after decompression (ITSE, CDA-CDB) were calculated before and after French-door laminoplasty decompression. (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA, B).\u003c/p\u003e \u003cp\u003e According to achieved improvement scores, patients were divided into two groups: Group 1 completed improvements of more than 3 points; Group 2 achieved improvements of less than or equal to 3 points. Moreover, patients were classified into two groups according to preoperative mJOA scores: Group A had preoperative mJOA scores greater than 10, and Group B had preoperative mJOA scores less than or equal to 10. Compare ISCF, IFSE, and ITSE between groups 1 and 2. Meanwhile, compare IFSE between groups A and B.\u003c/p\u003e \u003cp\u003eThen Spearman correlation analysis was used to analyze the correlations of these data with the mJOA score (preoperation mJOA score, one-year follow-up mJOA score). Differences between corresponding groups were compared using One-Way ANOVA.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eThirty-six patients with DCM underwent surgery, and IOUS with posterior French-door expansive laminoplasty, including 26 males and ten females, had an average age of 54.1 \u0026plusmn; 8.8 years (range 35\u0026ndash;78 years). The overall duration of symptoms averaged 31 \u0026plusmn; 15.05 months. No patient loss to follow-up or die at one-year after the operation. Among those patients, intraoperative blood loss was 137\u0026plusmn;58 ml, IOUS examination was 16.2\u0026plusmn;3.7 minutes, and the total operating time was 179.4\u0026plusmn;43.8 minutes (Table 1). After the operation, the neurological outcomes were assessed by the scoring system. The average preoperative mJOA score was 10.24\u0026plusmn;2.59, the postoperative mJOA score was 14.51\u0026plusmn;2.32, and improvements in mJOA scores were achieved with an average recovery rate of 64.29%\u0026plusmn;27.70%. Compared to the preoperative values, the average of achieved improvement scores in mJOA was 4.28\u0026plusmn;0.46, and the distribution of segments is shown in Table 2. Patients were divided into two groups according to achieved improvement scores: patients in group 1 achieved improvements of more than 3 points, and 18 patients were enrolled thereby; patients in group 2 achieved improvements of less than or equal to 3 points, and 18 patients were enrolled thereby (Table 4). Meanwhile, patients have been classified into two groups according to preoperative mJOA scores: patients in group A had preoperative mJOA scores greater than 10, and 18 patients were enrolled thereby; patients in group B had preoperative mJOA scores less than or equal to 10, and 18 patients were enrolled thereby (Table 5).\u003c/p\u003e\n\u003cp\u003eThe mean spinal cord diameter in the maximum compression area before French-door laminoplasty decompression (CDB) in MRI was 3.98\u0026plusmn;0.91 mm; the value in IOUS after decompression (CDA) was 5.36\u0026plusmn;1.11 mm. The largest hollow diameter in morphological changes before decompression (HDB) was 2.99\u0026plusmn;1.06 mm; after decompression (HDA), it was 1.60\u0026plusmn;0.71 mm. The space anterior to the cord in the midsagittal plane before decompression (SACB) was 5.08\u0026plusmn;1.11 mm, and after decompression (SACA), it was 6.08\u0026plusmn;1.28 mm. Regarding immediate measurements, the spinal cord float back (ISCF, SACA-SACB) was 1.01\u0026plusmn;0.49 mm, the front side of the spinal cord enlargement (IFSE, HDB-HDA) was 1.39\u0026plusmn;0.59 mm, and the total spinal cord enlargement after decompression (ITSE, CDA-CDB) was 1.39\u0026plusmn;0.84 mm (Table 3).\u003c/p\u003e\n\u003cp\u003eThe immediately measured\u0026nbsp;float back\u0026nbsp;distance after\u0026nbsp;decompression (ISCF, SACA-SACB) had a\u0026nbsp;positive correlation with\u0026nbsp;the\u0026nbsp;one-year follow-up mJOA score (P\u0026lt;0.01, r=0.68) and\u0026nbsp;a\u0026nbsp;positive correlation with\u0026nbsp;the\u0026nbsp;recovery rate of\u0026nbsp;the\u0026nbsp;mJOA score (P\u0026lt;0.01, r=0.72) (Fig. 3 A, B). Immediately\u0026nbsp;measured\u0026nbsp;enlargement of the front side of\u0026nbsp;the\u0026nbsp;spinal cord\u0026nbsp;(IFSE, HDB-HDA) had a\u0026nbsp;positive correlation with\u0026nbsp;the\u0026nbsp;one-year follow-up mJOA score (P\u0026lt;0.01, r=0.74) and\u0026nbsp;a\u0026nbsp;positive correlation with\u0026nbsp;the\u0026nbsp;recovery rate of\u0026nbsp;the\u0026nbsp;mJOA score (P\u0026lt;0.01, r=0.73) (Fig. 3 C, D). Immediately\u0026nbsp;measured\u0026nbsp;enlargement of the entire spinal cord (ITSE, CDA-CDB)\u0026nbsp;had a\u0026nbsp;positive correlation with\u0026nbsp;the\u0026nbsp;one-year follow-up mJOA score (P\u0026lt;0.01, r=0.64) and\u0026nbsp;a\u0026nbsp;positive correlation with\u0026nbsp;the\u0026nbsp;recovery rate of\u0026nbsp;the\u0026nbsp;mJOA score (P\u0026lt;0.01, r=0.71) (Fig. 3 E, F).\u0026nbsp;Interestingly, immediate\u0026nbsp;enlargement of the front side of\u0026nbsp;the\u0026nbsp;spinal cord (IFSE, HDB-HDA)\u0026nbsp;was positively correlated with the\u0026nbsp;preoperative mJOA score (P\u0026lt;0.05, r=0.36) (Fig. 3 G).\u003c/p\u003e\n\u003cp\u003eRegarding group 1, in which patients achieved improvements greater than three scores, values of ISCF, IFSE, and ITSE were all higher than those in group 2, in which patients achieved improvements less than or equal to 3 scores (P\u0026lt;0.05) (table 4, Fig. 4 A, B, C).\u003c/p\u003e\n\u003cp\u003eGroup A included patients with preoperative mJOA scores higher than 10, and Group B included patients with preoperative mJOA scores less than or equal to 10 (P\u0026lt;0.05) (Table 5, Fig. 5).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eFrench-door laminoplasty offers symmetrical decompression by opening the spinous processes' midline and hinging both laminae. Bilateral troughs are created on each lamina, thus creating a \"French door\" that allows the float-back spinal cord to move posteriorly[\u003cspan additionalcitationids=\"CR26\" citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. The spinal cord floats back, and enlargement can develop after surgery. Several studies have assessed the relationship between CT myelography and MRI changes in the spinal cord and clinical results[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eMorphological changes in the spinal cord after laminoplasty by CT myelography. The sagittal diameter of the spinal cord increased, and the rearward movement of the spinal cord in the supine position was more significant in the middle of the cervical spine[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. However, some changes occurred immediately and could not be observed by CT myelography and MRI. The extent of immediate spinal cord float back, and enlargement after French-door cervical laminoplasty decompression can be evaluated by preoperative MRI combined with IOUS. This study aimed to assess the relationship between immediate spinal cord float back and enlargement (including the front side of the spinal cord and the entire spinal cord) after French-door laminoplasty decompression and recovery of spinal cord function.\u003c/p\u003e \u003cp\u003eIn our research, preliminary data suggest that the extent of immediate spinal cord floating back, front side spinal cord enlargement, and total spinal cord enlargement after decompression during French-door laminoplasty have a positive correlation with the one-year follow-up mJOA score and the recovery rate of the mJOA score. Furthermore, we classified those patients who improved mJOA scores into two groups: 18 patients achieved scores greater than 3 in group 1, and 18 patients achieved scores less than or equal to 3 in group 2. In group 1, the values of ISCF, IFSE, and ITSE were all higher than those in group 2 (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). From this, it can be concluded that within limits, more float back, more enlargement of the front side of the spinal cord, and total spinal cord enlargement may be associated with a higher one-year follow-up mJOA score and recovery rate of mJOA score. Based on this, improving the immediate float back and enlargement of the spinal cord may further improve the postoperative recovery of spinal cord function.\u003c/p\u003e \u003cp\u003eOn the other hand, immediate enlargement of the front side of the spinal cord has a definite correlation with the one-year follow-up mJOA score and the recovery rate of the mJOA score and a solid correlation with the preoperative mJOA score. Then we classified patients into two groups according to preoperative mJOA scores: Group A patients had preoperative mJOA scores greater than 10, and 18 patients were enrolled thereby; group B patients had preoperative mJOA scores less than or equal to 10, and 18 patients were enrolled thereby. IFSE values in group A were higher than in group B (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). These findings indicate that the front side of the spinal cord accrued compensation due to the plasticity of the spinal cord[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e], and this observation helps predict preoperative and postoperative spinal cord function.\u003c/p\u003e \u003cp\u003eIn our previous study, the ratio of compressed to non-compressed areas of the spinal cord was measured to compare the overall expansion of the spinal cord[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. However, in posterior open-door surgery, the posterior is fully opened, and the recovery of anterior spinal cord compression is more critical. At the same time, in another study of our previous study, the gray value in the anterior of the spinal cord was more relevant to the recovery of the patient's motor function[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Due to the higher proportion of motor function in the JOA, the rally in front of the spinal cord is more related to the recovery of JOA.\u003c/p\u003e \u003cp\u003eFor DCM, complete posterior decompression can be achieved after posterior open-door laminectomy. Still, there are some differences in postoperative neurological function, which cannot wholly predict. However, even with complete decompression of the spinal cord and no anterior contact of the spinal cord, postoperative neurological recovery varies in different patients. There may be three reasons for this: First, the degree of spinal cord compression before an operation differs. Second, the time of spinal cord compression is different, and third, the location of spinal cord compression is different. Based on the above three reasons, it can be speculated that even if the exact decompression is performed, the various states of the spinal cord itself may lead to different spinal cord functions after decompression. This study evaluated the posterior shift of the spinal cord, the expansion of the whole spinal cord, and the growth of the anterior edge of the spinal cord, which partly reflected the state of the spinal cord itself. It could predict the recovery of neurological function to a certain extent. If the recovery prediction was not reasonable, we could consider further measures such as durotomy, spinal cord pia mater decompression, timely nutritional nerve, and functional exercise.\u003c/p\u003e \u003cp\u003eAnother study demonstrated spinal cord morphology and dynamics during cervical laminoplasty for DCM were classified into four grades. Restoration of the anterior subarachnoid space was considered a significant factor of neurologic improvement following posterior cervical decompression surgery[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. However, a previous study failed to find a substantial correlation between Clinical recovery and the subarachnoid space width in IOUS and MRI[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. This conclusion may be due to differences between categorical and continuous variables, different operating methods, a small set of samples, or only some degree of change will be associated with postoperative spinal cord function, and other reasons to produce this different result.\u003c/p\u003e \u003cp\u003eOf course, there are some limitations to the present study:1. The study\u0026rsquo;s sample size was small, and the follow-up period for postoperative evaluation of the JOA score (i.e., one year) was short. 2. The related data were measured on sagittal images in IOUS and MRI; however, those sagittal images were not in strict accordance. 3. Ultrasound procedures were performed by surgeons, which might impact the quality of ultrasound images. 4. The extent of immediate float back of the spinal cord and enlargement after French-door cervical laminoplasty decompression was evaluated by preoperative MRI combined with IOUS. \u0026ldquo;Immediate\u0026rdquo; generally means less than 30 minutes; however, this method does not strictly represent \u0026ldquo;immediately.\u0026rdquo; 5. IOUS was performed with the patient in the prone position, while MRI was performed with the patient in the supine position; this difference could be a source of some errors in parameter measurement.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn conclusion, IOUS helps evaluate spinal cord status in real-time after decompression. The extent of immediate float back of the spinal cord and enlargement after decompression in French-door cervical laminoplasty can be assessed by preoperative MRI combined with IOUS. These indications help predict the clinical outcome after French-door expansive laminoplasty.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eIOUS intraoperative ultrasound\u003c/p\u003e\n\u003cp\u003eMRI magnetic resonance imaging \u003c/p\u003e\n\u003cp\u003eDCM Degenerative cervical myelopathy \u003c/p\u003e\n\u003cp\u003eJOA Japanese Orthopaedic Association \u003c/p\u003e\n\u003cp\u003emJOA modified JOA \u003c/p\u003e\n\u003cp\u003eCT computed tomography \u003c/p\u003e\n\u003cp\u003eAP anteroposterior \u003c/p\u003e\n\u003cp\u003eROI the region of interest \u003c/p\u003e\n\u003cp\u003eRR recovery rate \u003c/p\u003e\n\u003cp\u003eDR dorsal roots \u003c/p\u003e\n\u003cp\u003eVR ventral roots \u003c/p\u003e\n\u003cp\u003eCSF cerebrospinal fluid \u003c/p\u003e\n\u003cp\u003eHDB the hollow diameter in the largest area of the spinal cord before decompression \u003c/p\u003e\n\u003cp\u003eHDA the hollow diameter in the largest area of the spinal cord after decompression \u003c/p\u003e\n\u003cp\u003eCDB the spinal cord diameter in the maximum compression area before decompression \u003c/p\u003e\n\u003cp\u003eCDA the spinal cord diameter in the maximum compression area after decompression \u003c/p\u003e\n\u003cp\u003eSACB the midsagittal space anterior to the cord before decompression \u003c/p\u003e\n\u003cp\u003eSACA the midsagittal space anterior to the cord after decompression \u003c/p\u003e\n\u003cp\u003eIFSE Then immediate front side of spinal cord enlargement (HDB-HDA) \u003c/p\u003e\n\u003cp\u003eITSE immediate total spinal cord enlargement after French-door laminoplasty decompression (CDA-CDB) \u003c/p\u003e\n\u003cp\u003eISCF immediate spinal cord float back (SACA-SACB)\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by The Seventh Affiliated Hospital of Sun Yat-sen University Ethics Committee. Written informed consent was obtained from all participants included in the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll participants, gave written and informed consent for publication for all personal or clinical details along with any identifying images to be published in this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors declare that they have no competing interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was funded by Foundation of Shenzhen Committee for Science and Technology Innovation (JCYJ20220530154800002), The Seventh Affiliated Hospital of SYSU, Clinical Research Fund (ZSQYLCKYJJ202018), Sanming Project of Medicine in Shenzhen (SZSM201911002), Zhejiang Provincial Natural Science Foundation of China (LQ20H170001), Joint Funds of the Zhejiang Provincial Natural Science Foundation of China (LBY21H170001), Basic Research Project of Shenzhen Science and Technology Innovation Commission (JCYJ20210324122807021), and Guangxi Key Laboratory of Basic and Translational Research of Bone and Joint Degenerative Disease (21-220-06).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eJL, FW,\u0026nbsp;and\u0026nbsp;WL\u0026nbsp;conceived of the presented idea.\u003c/p\u003e\n\u003cp\u003eJL, JW\u0026nbsp;and\u0026nbsp;WL\u0026nbsp;performed the ultrasound testing, carried out the radiological measurements, and interpretation of data.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eJL, HL\u0026nbsp;and\u0026nbsp;JW\u0026nbsp;carried out the clinical data collection.\u003c/p\u003e\n\u003cp\u003eJL, ZC\u0026nbsp;and\u0026nbsp;HL\u0026nbsp;analyzed the results and wrote the manuscript.\u003c/p\u003e\n\u003cp\u003eHL, SH and PC\u0026nbsp;performed the calculations and\u0026nbsp;statistical data.\u003c/p\u003e\n\u003cp\u003eAll authors discussed the results and contributed to the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003eAll authors reviewed the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e1\u0026nbsp;Department of\u0026nbsp;Orthopaedics, The\u0026nbsp;Seventh\u0026nbsp;Affiliated\u0026nbsp;Hospital\u0026nbsp;of\u0026nbsp;Sun\u0026nbsp;Yat-Sen\u0026nbsp;University, #628 Zhenyuan Road, Shenzhen, Guangdong 518100, China\u003c/p\u003e\n\u003cp\u003e2\u0026nbsp;Department of Orthopaedics, South China Hospital of Shenzhen University, #1 Fuxin Road, Shenzhen, Guangdong 518111, China\u003c/p\u003e\n\u003cp\u003e3 Department of Ultrasound, The Seventh Affiliated Hospital of Sun Yat-Sen University, #628 Zhenyuan Road, Shenzhen, Guangdong 518100, China\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eFehlings MG, Tetreault LA, Riew KD, Middleton JW, Aarabi B, Arnold PM, Brodke DS, Burns AS, Carette S, Chen R, et al. A Clinical Practice Guideline for the Management of Patients With Degenerative Cervical Myelopathy: Recommendations for Patients With Mild, Moderate, and Severe Disease and Nonmyelopathic Patients With Evidence of Cord Compression. Glob Spine J. 2017;7(3 Suppl):70S\u0026ndash;83S.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDavies BM, Mowforth OD, Smith EK, Kotter MR. Degenerative cervical myelopathy. Bmj-Brit Med J. 2018;360:k186.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHouten JK, Shahsavarani S, Verma RB. The Natural History of Degenerative Cervical Myelopathy. Clin Spine Surg. 2022;35(10):396\u0026ndash;402.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBadhiwala JH, Wilson JR. The Natural History of Degenerative Cervical Myelopathy. Neurosurg Clin N Am. 2018;29(1):21\u0026ndash;32.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOh T, Lafage R, Lafage V, Protopsaltis T, Challier V, Shaffrey C, Kim HJ, Arnold P, Chapman J, Schwab F, et al. Comparing Quality of Life in Cervical Spondylotic Myelopathy with Other Chronic Debilitating Diseases Using the Short Form Survey 36-Health Survey. World Neurosurg. 2017;106:699\u0026ndash;706.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFurlan JC, Catharine CB. Psychometric analysis and critical appraisal of the original, revised, and modified versions of the Japanese Orthopaedic Association score in the assessment of patients with cervical spondylotic myelopathy. Neurosurg Focus. 2016;40(6):E6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBadhiwala JH, Ahuja CS, Akbar MA, Witiw CD, Nassiri F, Furlan JC, Curt A, Wilson JR, Fehlings MG. Degenerative cervical myelopathy - update and future directions. Nat Rev Neurol. 2020;16(2):108\u0026ndash;24.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSangondimath G, Mallepally AR, Marathe N, Mak KC, Suman S. Degenerative cervical myelopathy: Recent updates and future directions. J Clin Orthop Trauma. 2020;11(5):822\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShedid D, Benzel EC. Cervical spondylosis anatomy: pathophysiology and biomechanics. Neurosurgery. 2007;60(1 Supp1 1):7\u0026ndash;S13.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTakahashi M, Yamashita Y, Sakamoto Y, Kojima R. Chronic cervical cord compression: clinical significance of increased signal intensity on MR images. Radiology. 1989;173(1):219\u0026ndash;24.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eArnasson O, Carlsson CA, Pellettieri L. Surgical and conservative treatment of cervical spondylotic radiculopathy and myelopathy. Acta Neurochir. 1987;84(1\u0026ndash;2):48\u0026ndash;53.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNakashima H, Yukawa Y, Suda K, Yamagata M, Ueta T, Kato F. Cervical Disc Protrusion Correlates With the Severity of Cervical Disc Degeneration: A Cross-Sectional Study of 1211 Relatively Healthy Volunteers. Spine. 2015;40(13):E774\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNouri A, Martin AR, Mikulis D, Fehlings MG. Magnetic resonance imaging assessment of degenerative cervical myelopathy: a review of structural changes and measurement techniques. Neurosurg Focus. 2016;40(6):E5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSions JM, Teyhen DS, Hicks GE. Criterion Validity of Ultrasound Imaging: Assessment of Multifidi Cross-Sectional Area in Older Adults With and Without Chronic Low Back Pain. J Geriatr Phys Ther. 2017;40(2):74\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGhamkhar L, Emami M, Mohseni-Bandpei MA, Behtash H. Application of rehabilitative ultrasound in the assessment of low back pain: a literature review. J Bodyw Mov Ther. 2011;15(4):465\u0026ndash;77.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu W, Li J, Zhou X, Chen N, Ouyang H, Xu Z, Zhu Y. Dynamic evaluation of the contractile function of lumbodorsal muscles during locust pose in yoga by real-time ultrasound. Bmc Sports Sci Med R. 2021;13(1):87.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTat J, Tat J, Yoon S, Yee A, Larouche J. Intraoperative Ultrasound in Spine Decompression Surgery: A Systematic Review. Spine. 2022;47(2):E73\u0026ndash;E85.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMihara H, Kondo S, Takeguchi H, Kohno M, Hachiya M. Spinal cord morphology and dynamics during cervical laminoplasty: evaluation with intraoperative sonography. Spine. 2007;32(21):2306\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNaruse T, Yanase M, Takahashi H, Horie Y, Ito M, Imaizumi T, Oguri K, Matsuyama Y. Prediction of clinical results of laminoplasty for cervical myelopathy focusing on spinal cord motion in intraoperative ultrasonography and postoperative magnetic resonance imaging. Spine. 2009;34(24):2634\u0026ndash;41.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWeinberg DS, Rhee JM. Cervical laminoplasty: indication, technique, complications. J Spine Surg. 2020;6(1):290\u0026ndash;301.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCho SK, Kim JS, Overley SC, Merrill RK. Cervical Laminoplasty: Indications, Surgical Considerations, and Clinical Outcomes. J Am Acad Orthop Sur. 2018;26(7):e142\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen G, Wei F, Shi L, Li J, Wang X, Wang M, Wu H, Xu Z, Liu X, Liu S. Inadequate spinal cord expansion in intraoperative ultrasound after decompression may predict neurological recovery of degenerative cervical myelopathy. Eur Radiol. 2021;31(11):8478\u0026ndash;87.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAita I, Hayashi K, Wadano Y, Yabuki T. Posterior movement and enlargement of the spinal cord after cervical laminoplasty. J Bone Joint Surg Br. 1998;80(1):33\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang L, Wei F, Liu S, Wan Y, Chen N, Cui S, Zhong R, Huang Y. Can Modified Kurokawa's Double-Door Laminoplasty Reduce the Incidence of Axial Symptoms at Long-term Follow-up? A Prospective Study of 152 Patients With Cervical Spondylotic Myelopathy. J Spinal Disord Tech. 2015;28(4):E186\u0026ndash;93.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWiguna I, Magetsari R, Noor Z, Suyitno S, Nindrea RD. Comparative Effectiveness and Functional Outcome of Open-Door versus French-Door Laminoplasty for Multilevel Cervical Myelopathy: A Meta-Analysis. Open Access Maced J Med Sci. 2019;7(19):3348\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHeller JG, Raich AL, Dettori JR, Riew KD. Comparative effectiveness of different types of cervical laminoplasty. Evid Based Spine Care J. 2013;4(2):105\u0026ndash;15.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAtkins D, Best D, Briss PA, Eccles M, Falck-Ytter Y, Flottorp S, Guyatt GH, Harbour RT, Haugh MC, Henry D, et al. Grading quality of evidence and strength of recommendations. Bmj-Brit Med J. 2004;328(7454):1490.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNouri A, Montejo J, Sun X, Virojanapa J, Kolb LE, Abbed KM, Cheng JS. Cervical Cord-Canal Mismatch: A New Method for Identifying Predisposition to Spinal Cord Injury. World Neurosurg. 2017;108:112\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen G, Wei F, Li J, Shi L, Zhang W, Wang X, Xu Z, Liu X, Zou X, Liu S. Intensity of Intraoperative Spinal Cord Hyperechogenicity as a Novel Potential Predictive Indicator of Neurological Recovery for Degenerative Cervical Myelopathy. Korean J Radiol. 2021;22(7):1163\u0026ndash;71.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBiczok A, Fuetsch M, Siller S, Patzig M, Tonn JC, Zausinger S. Intraoperative ultrasonography in laminectomy for degenerative cervical spondylotic myelopathy: a clinical and radiological evaluation. Acta Neurochir. 2022;164(7):1873\u0026ndash;81.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1. Details of the patients\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"558\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.89605734767025%\" valign=\"top\"\u003e\n \u003cp\u003eIndicator\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.10394265232975%\" valign=\"top\"\u003e\n \u003cp\u003eResults\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.89605734767025%\" valign=\"top\"\u003e\n \u003cp\u003eCases (number)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.10394265232975%\" valign=\"top\"\u003e\n \u003cp\u003e36\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.89605734767025%\" valign=\"top\"\u003e\n \u003cp\u003eSex (male/female)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.10394265232975%\" valign=\"top\"\u003e\n \u003cp\u003e26/10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.89605734767025%\" valign=\"top\"\u003e\n \u003cp\u003eAge at surgery, years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.10394265232975%\" valign=\"top\"\u003e\n \u003cp\u003e54.1 \u0026plusmn; 8.8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.89605734767025%\" valign=\"top\"\u003e\n \u003cp\u003eSymptom durations, months\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.10394265232975%\" valign=\"top\"\u003e\n \u003cp\u003e31 \u0026plusmn; 15.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.89605734767025%\" valign=\"top\"\u003e\n \u003cp\u003eIntraoperative blood loss, ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.10394265232975%\" valign=\"top\"\u003e\n \u003cp\u003e137\u0026plusmn;58\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.89605734767025%\" valign=\"top\"\u003e\n \u003cp\u003eIOUS examination time, minutes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.10394265232975%\" valign=\"top\"\u003e\n \u003cp\u003e16.2\u0026plusmn;3.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50.89605734767025%\" valign=\"top\"\u003e\n \u003cp\u003eOperating time, minutes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"49.10394265232975%\" valign=\"top\"\u003e\n \u003cp\u003e179.4\u0026plusmn;43.8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eTable 2. Distribution of segments and\u0026nbsp;mean\u0026nbsp;ISCF, ITSE, and IFSE.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eNumber\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eMean ISCF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eMean ITSE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eMean IFSE\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eC3/4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e0.93\u0026plusmn;0.46 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.31\u0026plusmn;0.74 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.26\u0026plusmn;0.47 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eC4/5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e0.98\u0026plusmn;0.48 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.37\u0026plusmn;0.87 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.37\u0026plusmn;0.53 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eC5/6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.08\u0026plusmn;0.52 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.45\u0026plusmn;0.90 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.44\u0026plusmn;0.66 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eC6/7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.00\u0026plusmn;0.47 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.35\u0026plusmn;0.78 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.40\u0026plusmn;0.61 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eTotal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.01\u0026plusmn;0.49 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.39\u0026plusmn;0.84 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.39\u0026plusmn;0.59 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eTable 3. Mean\u0026nbsp;CDB, CDA, ITSE, HDB, HDA, IFSE, SACB, SACA, and ISCF.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"560\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eSpinal cord diameter\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eHollow diameter\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eSpace anterior to the cord\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eBefore decompressed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e3.98\u0026plusmn;0.91 mm (CDB)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e2.99\u0026plusmn;1.06 mm (HDB)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e5.08\u0026plusmn;1.11 mm (SACB)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eAfter decompressed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e5.36\u0026plusmn;1.11 mm (CDA)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1.60\u0026plusmn;0.71 mm (HDA)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e6.08\u0026plusmn;1.28 mm (SACA)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eChange\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1.39\u0026plusmn;0.84 mm (ITSE)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1.39\u0026plusmn;0.59 mm (IFSE)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1.01\u0026plusmn;0.49 mm (ISCF)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eTable 4. Two groups achieved improved scores and detailed data of ISCF, IFSE, and ITSE in group 1 and group 2.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"\n \" width=\"553\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eGroup\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003en\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eISCF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eIFSE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eITSE\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.24\u0026plusmn;0.39 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.66\u0026plusmn;0.45 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.78\u0026plusmn;0.68 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e0.79\u0026plusmn;0.47 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.12\u0026plusmn;0.59 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e1.00\u0026plusmn;0.82 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003e36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eP＜0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eP＜0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20%\" valign=\"top\"\u003e\n \u003cp\u003eP＜0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eTable 5. According to preoperative mJOA scores, two groups detailed data of IFSE in groups A and B.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"558\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.333333333333336%\" valign=\"top\"\u003e\n \u003cp\u003eGroup\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"33.333333333333336%\" valign=\"top\"\u003e\n \u003cp\u003en\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"33.333333333333336%\" valign=\"top\"\u003e\n \u003cp\u003eIFSE\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.333333333333336%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"33.333333333333336%\" valign=\"top\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"33.333333333333336%\" valign=\"top\"\u003e\n \u003cp\u003e1.67\u0026plusmn;0.55 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.333333333333336%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"33.333333333333336%\" valign=\"top\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"33.333333333333336%\" valign=\"top\"\u003e\n \u003cp\u003e1.11\u0026plusmn;0.49 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.333333333333336%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"33.333333333333336%\" valign=\"top\"\u003e\n \u003cp\u003e36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"33.333333333333336%\" valign=\"top\"\u003e\n \u003cp\u003eP＜0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"intraoperative ultrasound , Japanese Orthopaedic Association score , degenerative cervical myelopathy , French-door expansive laminoplasty , magnetic resonance imaging","lastPublishedDoi":"10.21203/rs.3.rs-3385824/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3385824/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003cb\u003eBackground\u003c/b\u003e Spinal cord floating and enlargement can develop after cervical laminectomy and laminoplasty, it determines whether completely decompress the cord. To assess the relationship between immediate float back and enlargement of the spinal cord after decompression and subsequent recovery of spinal cord function.\u003c/p\u003e \u003cp\u003e \u003cb\u003eMethods\u003c/b\u003e The parameters associated with float back and enlargement of the spinal cord in Intraoperative ultrasound (IOUS) and preoperative MRI were investigated. Spinal cord function recovery was also investigated as measured by the mJOA score at the one-year follow-up.\u003c/p\u003e \u003cp\u003e \u003cb\u003eResults\u003c/b\u003e The average preoperative mJOA score was 10.24\u0026thinsp;\u0026plusmn;\u0026thinsp;2.59, the postoperative mJOA score was 14.51\u0026thinsp;\u0026plusmn;\u0026thinsp;2.32, and improvements in mJOA score were achieved with an average recovery rate of 64.29%\u0026plusmn;27.70%. The immediate float back distance after decompression (1.01\u0026thinsp;\u0026plusmn;\u0026thinsp;0.49 mm) was positively correlated with the one-year follow-up mJOA score (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01, r\u0026thinsp;=\u0026thinsp;0.68) and the recovery rate of the mJOA score (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01, r\u0026thinsp;=\u0026thinsp;0.72). The immediate enlargement of the spinal cord (1.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.84 mm) was positively correlated with the one-year follow-up mJOA score (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01, r\u0026thinsp;=\u0026thinsp;0.64) and the recovery rate of the mJOA score (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01, r\u0026thinsp;=\u0026thinsp;0.71). Immediate enlargement of the front side of the spinal cord (1.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.59 mm) was positively correlated with the one-year follow-up mJOA score (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01, r\u0026thinsp;=\u0026thinsp;0.74) and the recovery rate of the mJOA score (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01, r\u0026thinsp;=\u0026thinsp;0.73). Interestingly, only enlargement of the front side of the spinal cord was positively correlated with the preoperative mJOA score (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05, r\u0026thinsp;=\u0026thinsp;0.36).\u003c/p\u003e \u003cp\u003e \u003cb\u003eConclusions\u003c/b\u003e The extent of immediate spinal cord float back, and enlargement after decompression in French-door cervical laminoplasty can be evaluated using preoperative MRI combined with IOUS, and these indications help predict the clinical outcome after French-door expansive laminoplasty.\u003c/p\u003e","manuscriptTitle":"Intraoperative ultrasound combined with MRI for evaluating float back and enlargement of the spinal cord after cervical laminoplasty in the management of degenerative cervical myelopathy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-10-06 20:18:27","doi":"10.21203/rs.3.rs-3385824/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"357170b4-d648-42ff-a5ec-30fef1e4bb6a","owner":[],"postedDate":"October 6th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-05-08T13:51:07+00:00","versionOfRecord":[],"versionCreatedAt":"2023-10-06 20:18:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3385824","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3385824","identity":"rs-3385824","version":["v1"]},"buildId":"uzvnyPIH0yfUW73ClG4p1","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}