A clinical experience in treating myelopathy caused by floating lamina resulting from re-close of the lamina and pseudarthrosis at the lateral gutter after cervical laminoplasty.

A clinical experience in treating myelopathy caused by floating lamina resulting from re-close of the lamina and pseudarthrosis at the lateral gutter after cervical laminoplasty. | 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 Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report A clinical experience in treating myelopathy caused by floating lamina resulting from re-close of the lamina and pseudarthrosis at the lateral gutter after cervical laminoplasty. Arihiko Tsukamoto, Takashi Oshima, Shutaro Fujimoto, Ryunosuke Fukushi, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6504824/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 The patient was a 68-year-old man who presented with myelopathy caused by a floating lamina resulting from pseudoarthrosis at the lateral gutter and reclosure of the lamina following cervical laminoplasty. Intraoperatively, the C2 and C3 laminae were found to be mobile. To avoid spinal cord injury, the laminae were stabilized using forceps while carefully drilling them with a high-speed burr under spinal cord monitoring. Scar tissue was removed, and the dural sac was decompressed. The patient’s symptoms improved early after surgery. It has been reported that medial deviation of the lateral gutter can result in insufficient spinal cord decompression and increased damage to the inner cortex of the lamina, which can lead to pseudoarthrosis and subsequent reclosure of the lamina. In the present case, there was no evidence of kyphotic deformity or spinal instability. However, the initial surgery involved a narrow lateral gutter, which likely led to gradual reclosure of the lamina. Osteophyte formation due to pseudoarthrosis at the lateral gutter also contributed to the recurrence of myelopathy. Laminoplasty Floating lamina Re-close of lamina Pseudarthrosis of the lateral gutter Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Various techniques for cervical laminoplasty have been reported, including the double-door method, open-door method, and skip laminectomy ( 1 , 2 , 3 ). Here, we report a case of myelopathy caused by pseudarthrosis at the lateral gutter and reclosure of the lamina due to malposition of the lateral gutter. Case Presentation The patient was a 68-year-old male who presented with gait instability, fine motor dysfunction of the fingers, and numbness in both upper limbs. Eight years earlier, he had undergone C2–C5 laminoplasty at a previous hospital for numbness in both upper limbs, which resulted in symptomatic relief. However, six months ago, the numbness recurred, prompting him to consult the previous hospital again. Due to comorbidities, he was referred to our institution. Subsequently, the numbness in his upper limbs gradually worsened, and he developed fine motor impairment in his fingers and gait instability. Although surgery was planned, it had to be postponed due to the onset of pulmonary thromboembolism. Once anticoagulation therapy could be temporarily discontinued, the surgery was performed. His medical history included thoracic plasmacytoma, for which he was undergoing chemotherapy. On examination, the patient exhibited numbness and impaired temperature and pain sensation throughout both upper limbs. He had experienced multiple episodes of urinary incontinence, indicating bladder and bowel dysfunction. Due to spasticity and unsteadiness, independent walking was difficult. Fine motor dysfunction of the fingers made buttoning clothes and writing difficult. Muscle strength was mildly reduced to MMT grade 4 in both upper limbs below the deltoid muscles. The biceps, brachioradialis, and triceps tendon reflexes were hyperactive. In the lower limbs, tendon reflexes were also hyperactive, and bilateral ankle clonus was present. Both Hoffmann's and Trömner's reflexes were positive bilaterally. The finger escape sign was grade 2 on the right and grade 1 on the left. In the 10-second test, the patient was able to perform 13 movements on both sides. The Romberg sign was positive. In the previous preoperative plain radiographs, no abnormalities in cervical alignment were observed. MRI showed spinal cord compression at the C2/3, C4/5, and C5/6 levels (Fig. 1). A C2–C5 double-door laminoplasty was performed. Postoperative CT revealed a narrow lateral gutter at C3 and damage to the inner lamina, but adequate opening of the lamina was achieved, and the spacer was positioned appropriately (Fig. 2). In the current preoperative plain radiographs, there was no deterioration in alignment, and no evidence of vertebral slippage or intervertebral instability (Fig. 3). MRI showed spinal cord compression and signal changes at the C3 and C3/4 levels. CT myelography revealed non-union of the lateral gutters at C2 and C3 with osteophyte formation, and the lamina had reclosed. Marked spinal cord compression was observed at the C2–3 laminar level (Fig. 4). The surgical strategy was to first perform posterior resection of the C2 and C3 laminae. If postoperative decompression was deemed insufficient or if symptoms did not improve, anterior decompression and fusion would be considered as an additional procedure. Intraoperatively, the C2 and C3 laminae were found to be floating. While the assistant stabilized the laminae with forceps, they were carefully resected using a high-speed drill along with the artificial bone. Although there was a partial decrease in motor evoked potentials (MEP) during surgery, lamina removal was continued with care. The dura mater was found to be adherent and scarred; the epidural scar tissue was carefully removed, and decompression was confirmed before concluding the procedure. Postoperatively, numbness in both upper limbs temporarily worsened but subsequently improved. MRI confirmed adequate decompression of the spinal cord, and thus anterior surgery was not performed(Fig. 5). Fine motor function of the fingers and gait instability improved, and urinary incontinence resolved. The patient was discharged home two weeks after surgery. The preoperative Japanese Orthopaedic Association (JOA) score was 7.5, which improved to 14.5 three months postoperatively, with a recovery rate of 73.7%. Discussion Regarding revision surgery after cervical laminoplasty, Hashimoto reported that 40 out of 4,208 cases required reoperation. The causes included 10 cases of radiculopathy, 8 cases of adjacent segment stenosis, 6 cases of spacer subsidence, 4 cases of instability, 3 cases of OPLL, 3 cases of disc herniation, 2 cases of trauma, 2 cases of postoperative scarring, 1 case of ossification of the anterior longitudinal ligament (ALL), and 2 cases of unknown cause ( 4 ). Jimbayashi reported that out of 169 patients who underwent cervical laminoplasty, 5 required reoperation due to reclosure of the lamina. All patients with laminar reclosure showed postoperative progression of kyphosis ( 5 ). They also noted that patients requiring reoperation tended to have neuromuscular or psychiatric disorders and that many had a preoperative C2–C7 lordotic angle of less than − 10 degrees. The causes of restenosis after cervical laminoplasty have been attributed to inadequate decompression width during the initial surgery, insufficient cranial-caudal decompression range, postoperative kyphotic deformity progression, and enlargement of OPLL or osteophytes ( 6 , 7 ). In the present case, no significant postoperative kyphotic deformity, OPLL progression, or intervertebral osteophyte enlargement was observed. However, the initial lateral gutter was narrow, leading to gradual reclosure of the lamina and osteophyte formation at the pseudarthrosis site, which likely caused recurrence of myelopathy. Sakai et al. reported that, one year after laminoplasty in 110 cases, laminar reclosure occurred in 6 cases, and outcomes in the reclosure group were poor. They also reported that reclosure occurred more frequently with anchor-based techniques than with spacer-based ones, and that older age, larger cervical sagittal vertical axis (CSVA), and progression of kyphosis were risk factors for laminar reclosure ( 8 ). In the present case, the patient was not of advanced age at the time of the initial surgery (60 years old), spacers were used, and no postoperative kyphotic deformity was observed. Regarding the creation of the lateral gutter, Ueda et al. reported that placing the gutter on the medial pedicular line achieves the greatest expansion of the spinal canal. When the gutter is placed too laterally, it becomes difficult to elevate the lamina and may cause axial pain due to facet joint destruction. Conversely, when the gutter is placed too medially, insufficient spinal cord decompression can occur, and damage to the laminar inner plate increases, potentially leading to pseudarthrosis and subsequent reclosure of the lamina ( 9 ). In this case, postoperative CT images revealed that the lateral gutters were placed medially to the medial pedicular line on both sides, and damage to the inner laminar plate was also noted. These findings are believed to have contributed to the development of pseudarthrosis at the lateral gutters and subsequent reclosure of the lamina. The occurrence of myelopathy due to osteophyte formation at the pseudarthrosis site and reclosure of the lamina eight years after surgery is extremely rare. There have been reports of surgery for myelopathy caused by floating lamina due to congenital anomalies of the axis. In these cases, decompression was successfully achieved by resecting the floating lamina without drilling ( 10 – 12 ). Drilling a floating lamina carries a significant risk of spinal cord injury and is considered highly dangerous. In the present case, due to postoperative adhesions, it was expected that direct resection of the lamina could lead to dural defects. Indeed, intraoperatively, there was scar formation and adhesion in the epidural space. Therefore, frequent use of spinal cord monitoring was employed during surgery, and the assistant stabilized the lamina with forceps while the lamina was carefully and gradually drilled away over time. As a result, no postoperative paralysis occurred. Regarding lamina stabilization, because there was no soft tissue such as the semispinalis cervicis attached due to prior surgery, mechanical fixation or traction with surrounding tissues was difficult, and manual stabilization was considered most effective. Additionally, to avoid pressing on the lamina during drilling, a steel burr was used for the hard artificial spacer material, while a diamond burr was used for the lamina itself. For floating lamina, in cases without epidural adhesions, resection should be performed, whereas in cases where adhesions are expected, careful and time-consuming drilling is essential. Conclusion This case illustrates a rare but significant complication of myelopathy caused by a floating lamina due to reclosure of the lamina following cervical laminoplasty. Although no apparent postoperative kyphotic deformity or instability was observed, the narrow lateral gutter and damage to the inner lamina during the initial surgery are considered contributing factors to pseudoarthrosis and subsequent reclosure. In cases where the lamina is mobile and adhesions are anticipated, careful drilling with secure fixation of the lamina under neuromonitoring is essential. To prevent reclosure, it is crucial to create an appropriately positioned lateral gutter during the initial surgery and to remain vigilant about the risk of recurrence over long-term follow-up. Declarations Acknowledgements : The author would like to thank all co-authors for advice on the preparation of the paper. We are grateful to the referees for useful comments. Competing Interests : The authors have no relevant financial or non-financial interests to disclose. Funding : This research received no external funding. Informed Consent : Written informed consent was obtained from the patient for publication of this case report and any accompanying images. Author Contribution A.T and T.O performed the surgery and collected the clinical data. S.F and R.F analyzed the imaging findings. T.M wrote the initial draft of the manuscript. All authors discussed the case, contributed to the interpretation of the findings, and reviewed and approved the final manuscript. References Miyazaki K, Tada K, Matsuda Y et al (1989) Posterior extensive simultaneous multisegment decompression with posterolateral fusion for cervical myelopathy with cervical instability and kyphotic and/or s-shaped deformities. Spine 14(11):1160–1170 Satomi K, Nishu Y, Kohno T et al (2016) Long-term follow-up studies of open-door expansive laminoplasty for cervical stenotic myelopathy. Spine 41:299–305 Kimura I, Shingu H, Nasu Y et al (1995) Long-term follow-up studies of cervical spondylotic myelopathy treated by canal-expansive laminoplasty. J Bone Joint Surg Br 77:956–961 Hashimoto K, Aizawa T, Ozawa H et al (2019) Reoperation Rates after Laminoplasty for Cervical Disorders: A 26-Year Period Survival Function Method Analysis. Spine Surg Relat Res 3:304–311 Jimbayashi H, Iida K, Kobayakawa K et al (2023) Cases requiring reoperation for recurrence of myelopathy bylamina closure after a double-door laminoplasty using a modified Kirita-Miyazaki suture method. J Orthop 44:12–16 Yamazaki A, Homma T, Uchiyama S et al (1999) Morphologic limitations of posterior decompression by midsagittal splitting method for myelopathy caused by ossification of the posterior longitudinal ligament in the cervical spine. Spine 24(1):32–34 Kimura S, Homma T, Uchiyama S et al (1995) Posterior migration of cervical spinal cord between split laminae as a complication of laminoplasty. Spine 20(11):1284–1288 Sakai K, Hirai T, Arai Y et al (2021) Laminar Closure in Double-door Laminoplasty for cervical Spondylotic Myelopathy with Nonkyphotic Alignment. Spine 46(15):999–1006 Ueda S, Ioroi Y, Fukuda M et al (2011) Anatomical Evaluation of the Lateral Hinge in Cervical Laminoplasty. Spinal Surg 25(2):147–152 Nakashima T, Otsuki B, Shimizu T et al (2020) Cervical Myelopathy Caused by Invagination of Floating Anomalous C2 and C3 Laminae in the Spinal Canal. Spine Surg Relat Res 20(4):274–276 Sakaura H, Yasui Y, Miwa T et al (2013) Cervical myelopathy caused by invagination of anomalous lamina of the axis. J Neurosurg Spine 19:694–494 Jian-Xiang X, Cheng-Gui W, Cheng-Wei Z et al (2017) Cervical myelopathy caused by invaginated laminae of the axis associated with occipitalization of the atlas. Medicine 96:51 Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board 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-6504824","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":472362291,"identity":"f7693b40-f3bd-40b4-8224-7281bd0e7463","order_by":0,"name":"Arihiko 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Morita","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Tomonori","middleName":"","lastName":"Morita","suffix":""},{"id":472362296,"identity":"bd631340-c805-4efc-b953-2af72e6b0a72","order_by":5,"name":"Atsushi Teramoto","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Atsushi","middleName":"","lastName":"Teramoto","suffix":""}],"badges":[],"createdAt":"2025-04-22 13:38:10","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6504824/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6504824/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":85364532,"identity":"78af0a0a-dfbf-4e2b-8b71-1c372bcdd602","added_by":"auto","created_at":"2025-06-25 06:32:53","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":170333,"visible":true,"origin":"","legend":"\u003cp\u003ePreoperative images before the initial surgery\u003c/p\u003e\n\u003cp\u003ePlain lateral radiographs A: Neutral position B: Flexion C: Extension No abnormal alignment or dynamic instability was observed.\u003cbr\u003e\nD: Sagittal MRI image Spinal cord compression is evident at the C2/3, C4/5, and C5/6 levels.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6504824/v1/f6eab4a78c4483284422a833.png"},{"id":85364530,"identity":"7f5c86cd-6365-40e4-b209-80335ceddcc0","added_by":"auto","created_at":"2025-06-25 06:32:53","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":177817,"visible":true,"origin":"","legend":"\u003cp\u003ePostoperative CT after the initial surgery\u003c/p\u003e\n\u003cp\u003eA:Sagittal view B: Axial view at the C2 lamina level C: Axial view at the C3 lamina level\u003cbr\u003e\nLamina inner plate damage at the lateral gutters is observed at both C2 and C3, but the spacers are well positioned, and sufficient laminar opening was achieved.\u003c/p\u003e\n\u003cp\u003eAt the C3 level, the lateral gutters were created medial to the medial pedicular line.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6504824/v1/025ce74e156af36263cbecff.png"},{"id":85364529,"identity":"2ded3788-a0ee-416c-8549-4b528aa799d9","added_by":"auto","created_at":"2025-06-25 06:32:53","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":105647,"visible":true,"origin":"","legend":"\u003cp\u003ePreoperative plain lateral radiographs for the current surgery\u003cbr\u003e\nA: Anteroposterior view B: Neutral lateral view C: Flexion view D: Extension view\u003cbr\u003e\nNo alignment abnormalities or dynamic instability were observed.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6504824/v1/d26a2d4260097143bd6f7c0b.png"},{"id":85365977,"identity":"569fdaba-3efe-494c-9f57-be274c90e32c","added_by":"auto","created_at":"2025-06-25 06:48:53","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":126069,"visible":true,"origin":"","legend":"\u003cp\u003ePreoperative CT Myelography for the Current Surgery\u003c/p\u003e\n\u003cp\u003eA: Sagittal view B–E: Axial view B: C3 level C: Inferior edge of C3 D: Superior edge of C4 E: C4 level\u003c/p\u003e\n\u003cp\u003ePseudarthrosis and osteophyte formation at the lateral gutters of the C2 and C3 laminae, as well as laminar reclosure, were observed. Severe spinal cord compression was noted at the C2/3 laminar level.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6504824/v1/059a49dff96287af9a22e18f.png"},{"id":85363703,"identity":"07fb8941-737c-4f4a-b240-fe248b581f7d","added_by":"auto","created_at":"2025-06-25 06:24:53","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":149296,"visible":true,"origin":"","legend":"\u003cp\u003eA: Intraoperative Photo After Decompression B–E: Postoperative Images\u003c/p\u003e\n\u003cp\u003eB: Lateral plain radiograph C: Sagittal MRI D: Axial view at the inferior edge of C3 \u0026nbsp;E: Axial view at the superior edge of C4\u003c/p\u003e\n\u003cp\u003eAdequate spinal cord decompression was achieved.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6504824/v1/05ec600c943fcb2d93add38d.png"},{"id":87989046,"identity":"ad4f6f96-28bb-4a76-89c9-cb98c12bca5d","added_by":"auto","created_at":"2025-07-31 08:02:14","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1202462,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6504824/v1/785f1257-23c7-4eee-91cd-df87b50743d6.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A clinical experience in treating myelopathy caused by floating lamina resulting from re-close of the lamina and pseudarthrosis at the lateral gutter after cervical laminoplasty.","fulltext":[{"header":"Introduction","content":"\u003cp\u003eVarious techniques for cervical laminoplasty have been reported, including the double-door method, open-door method, and skip laminectomy (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). Here, we report a case of myelopathy caused by pseudarthrosis at the lateral gutter and reclosure of the lamina due to malposition of the lateral gutter.\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eThe patient was a 68-year-old male who presented with gait instability, fine motor dysfunction of the fingers, and numbness in both upper limbs. Eight years earlier, he had undergone C2\u0026ndash;C5 laminoplasty at a previous hospital for numbness in both upper limbs, which resulted in symptomatic relief. However, six months ago, the numbness recurred, prompting him to consult the previous hospital again. Due to comorbidities, he was referred to our institution. Subsequently, the numbness in his upper limbs gradually worsened, and he developed fine motor impairment in his fingers and gait instability. Although surgery was planned, it had to be postponed due to the onset of pulmonary thromboembolism. Once anticoagulation therapy could be temporarily discontinued, the surgery was performed. His medical history included thoracic plasmacytoma, for which he was undergoing chemotherapy. On examination, the patient exhibited numbness and impaired temperature and pain sensation throughout both upper limbs. He had experienced multiple episodes of urinary incontinence, indicating bladder and bowel dysfunction. Due to spasticity and unsteadiness, independent walking was difficult. Fine motor dysfunction of the fingers made buttoning clothes and writing difficult. Muscle strength was mildly reduced to MMT grade 4 in both upper limbs below the deltoid muscles. The biceps, brachioradialis, and triceps tendon reflexes were hyperactive. In the lower limbs, tendon reflexes were also hyperactive, and bilateral ankle clonus was present. Both Hoffmann's and Tr\u0026ouml;mner's reflexes were positive bilaterally. The finger escape sign was grade 2 on the right and grade 1 on the left. In the 10-second test, the patient was able to perform 13 movements on both sides. The Romberg sign was positive. In the previous preoperative plain radiographs, no abnormalities in cervical alignment were observed. MRI showed spinal cord compression at the C2/3, C4/5, and C5/6 levels (Fig.\u0026nbsp;1). A C2\u0026ndash;C5 double-door laminoplasty was performed. Postoperative CT revealed a narrow lateral gutter at C3 and damage to the inner lamina, but adequate opening of the lamina was achieved, and the spacer was positioned appropriately (Fig.\u0026nbsp;2). In the current preoperative plain radiographs, there was no deterioration in alignment, and no evidence of vertebral slippage or intervertebral instability (Fig.\u0026nbsp;3). MRI showed spinal cord compression and signal changes at the C3 and C3/4 levels. CT myelography revealed non-union of the lateral gutters at C2 and C3 with osteophyte formation, and the lamina had reclosed. Marked spinal cord compression was observed at the C2\u0026ndash;3 laminar level (Fig.\u0026nbsp;4). The surgical strategy was to first perform posterior resection of the C2 and C3 laminae. If postoperative decompression was deemed insufficient or if symptoms did not improve, anterior decompression and fusion would be considered as an additional procedure. Intraoperatively, the C2 and C3 laminae were found to be floating. While the assistant stabilized the laminae with forceps, they were carefully resected using a high-speed drill along with the artificial bone. Although there was a partial decrease in motor evoked potentials (MEP) during surgery, lamina removal was continued with care. The dura mater was found to be adherent and scarred; the epidural scar tissue was carefully removed, and decompression was confirmed before concluding the procedure. Postoperatively, numbness in both upper limbs temporarily worsened but subsequently improved. MRI confirmed adequate decompression of the spinal cord, and thus anterior surgery was not performed(Fig.\u0026nbsp;5). Fine motor function of the fingers and gait instability improved, and urinary incontinence resolved. The patient was discharged home two weeks after surgery. The preoperative Japanese Orthopaedic Association (JOA) score was 7.5, which improved to 14.5 three months postoperatively, with a recovery rate of 73.7%.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eRegarding revision surgery after cervical laminoplasty, Hashimoto reported that 40 out of 4,208 cases required reoperation. The causes included 10 cases of radiculopathy, 8 cases of adjacent segment stenosis, 6 cases of spacer subsidence, 4 cases of instability, 3 cases of OPLL, 3 cases of disc herniation, 2 cases of trauma, 2 cases of postoperative scarring, 1 case of ossification of the anterior longitudinal ligament (ALL), and 2 cases of unknown cause (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eJimbayashi reported that out of 169 patients who underwent cervical laminoplasty, 5 required reoperation due to reclosure of the lamina. All patients with laminar reclosure showed postoperative progression of kyphosis (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). They also noted that patients requiring reoperation tended to have neuromuscular or psychiatric disorders and that many had a preoperative C2\u0026ndash;C7 lordotic angle of less than \u0026minus;\u0026thinsp;10 degrees.\u003c/p\u003e \u003cp\u003eThe causes of restenosis after cervical laminoplasty have been attributed to inadequate decompression width during the initial surgery, insufficient cranial-caudal decompression range, postoperative kyphotic deformity progression, and enlargement of OPLL or osteophytes (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). In the present case, no significant postoperative kyphotic deformity, OPLL progression, or intervertebral osteophyte enlargement was observed. However, the initial lateral gutter was narrow, leading to gradual reclosure of the lamina and osteophyte formation at the pseudarthrosis site, which likely caused recurrence of myelopathy.\u003c/p\u003e \u003cp\u003eSakai et al. reported that, one year after laminoplasty in 110 cases, laminar reclosure occurred in 6 cases, and outcomes in the reclosure group were poor. They also reported that reclosure occurred more frequently with anchor-based techniques than with spacer-based ones, and that older age, larger cervical sagittal vertical axis (CSVA), and progression of kyphosis were risk factors for laminar reclosure (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). In the present case, the patient was not of advanced age at the time of the initial surgery (60 years old), spacers were used, and no postoperative kyphotic deformity was observed. Regarding the creation of the lateral gutter, Ueda et al. reported that placing the gutter on the medial pedicular line achieves the greatest expansion of the spinal canal. When the gutter is placed too laterally, it becomes difficult to elevate the lamina and may cause axial pain due to facet joint destruction. Conversely, when the gutter is placed too medially, insufficient spinal cord decompression can occur, and damage to the laminar inner plate increases, potentially leading to pseudarthrosis and subsequent reclosure of the lamina (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn this case, postoperative CT images revealed that the lateral gutters were placed medially to the medial pedicular line on both sides, and damage to the inner laminar plate was also noted. These findings are believed to have contributed to the development of pseudarthrosis at the lateral gutters and subsequent reclosure of the lamina. The occurrence of myelopathy due to osteophyte formation at the pseudarthrosis site and reclosure of the lamina eight years after surgery is extremely rare.\u003c/p\u003e \u003cp\u003eThere have been reports of surgery for myelopathy caused by floating lamina due to congenital anomalies of the axis. In these cases, decompression was successfully achieved by resecting the floating lamina without drilling (\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). Drilling a floating lamina carries a significant risk of spinal cord injury and is considered highly dangerous. In the present case, due to postoperative adhesions, it was expected that direct resection of the lamina could lead to dural defects. Indeed, intraoperatively, there was scar formation and adhesion in the epidural space.\u003c/p\u003e \u003cp\u003eTherefore, frequent use of spinal cord monitoring was employed during surgery, and the assistant stabilized the lamina with forceps while the lamina was carefully and gradually drilled away over time. As a result, no postoperative paralysis occurred. Regarding lamina stabilization, because there was no soft tissue such as the semispinalis cervicis attached due to prior surgery, mechanical fixation or traction with surrounding tissues was difficult, and manual stabilization was considered most effective.\u003c/p\u003e \u003cp\u003eAdditionally, to avoid pressing on the lamina during drilling, a steel burr was used for the hard artificial spacer material, while a diamond burr was used for the lamina itself. For floating lamina, in cases without epidural adhesions, resection should be performed, whereas in cases where adhesions are expected, careful and time-consuming drilling is essential.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis case illustrates a rare but significant complication of myelopathy caused by a floating lamina due to reclosure of the lamina following cervical laminoplasty. Although no apparent postoperative kyphotic deformity or instability was observed, the narrow lateral gutter and damage to the inner lamina during the initial surgery are considered contributing factors to pseudoarthrosis and subsequent reclosure. In cases where the lamina is mobile and adhesions are anticipated, careful drilling with secure fixation of the lamina under neuromonitoring is essential. To prevent reclosure, it is crucial to create an appropriately positioned lateral gutter during the initial surgery and to remain vigilant about the risk of recurrence over long-term follow-up.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003eThe author would like to thank all co-authors for advice on the preparation of the paper. We are grateful to the referees for useful comments.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThis research received no external funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed Consent\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003eWritten informed consent was obtained from the patient for publication of this case report and any accompanying images.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA.T and T.O performed the surgery and collected the clinical data. S.F and R.F analyzed the imaging findings. T.M wrote the initial draft of the manuscript. All authors discussed the case, contributed to the interpretation of the findings, and reviewed and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eMiyazaki K, Tada K, Matsuda Y et al (1989) Posterior extensive simultaneous multisegment decompression with posterolateral fusion for cervical myelopathy with cervical instability and kyphotic and/or s-shaped deformities. Spine 14(11):1160\u0026ndash;1170\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSatomi K, Nishu Y, Kohno T et al (2016) Long-term follow-up studies of open-door expansive laminoplasty for cervical stenotic myelopathy. Spine 41:299\u0026ndash;305\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKimura I, Shingu H, Nasu Y et al (1995) Long-term follow-up studies of cervical spondylotic myelopathy treated by canal-expansive laminoplasty. J Bone Joint Surg Br 77:956\u0026ndash;961\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHashimoto K, Aizawa T, Ozawa H et al (2019) Reoperation Rates after Laminoplasty for Cervical Disorders: A 26-Year Period Survival Function Method Analysis. Spine Surg Relat Res 3:304\u0026ndash;311\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJimbayashi H, Iida K, Kobayakawa K et al (2023) Cases requiring reoperation for recurrence of myelopathy bylamina closure after a double-door laminoplasty using a modified Kirita-Miyazaki suture method. J Orthop 44:12\u0026ndash;16\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYamazaki A, Homma T, Uchiyama S et al (1999) Morphologic limitations of posterior decompression by midsagittal splitting method for myelopathy caused by ossification of the posterior longitudinal ligament in the cervical spine. Spine 24(1):32\u0026ndash;34\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKimura S, Homma T, Uchiyama S et al (1995) Posterior migration of cervical spinal cord between split laminae as a complication of laminoplasty. Spine 20(11):1284\u0026ndash;1288\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSakai K, Hirai T, Arai Y et al (2021) Laminar Closure in Double-door Laminoplasty for cervical Spondylotic Myelopathy with Nonkyphotic Alignment. Spine 46(15):999\u0026ndash;1006\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUeda S, Ioroi Y, Fukuda M et al (2011) Anatomical Evaluation of the Lateral Hinge in Cervical Laminoplasty. Spinal Surg 25(2):147\u0026ndash;152\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNakashima T, Otsuki B, Shimizu T et al (2020) Cervical Myelopathy Caused by Invagination of Floating Anomalous C2 and C3 Laminae in the Spinal Canal. Spine Surg Relat Res 20(4):274\u0026ndash;276\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSakaura H, Yasui Y, Miwa T et al (2013) Cervical myelopathy caused by invagination of anomalous lamina of the axis. J Neurosurg Spine 19:694\u0026ndash;494\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJian-Xiang X, Cheng-Gui W, Cheng-Wei Z et al (2017) Cervical myelopathy caused by invaginated laminae of the axis associated with occipitalization of the atlas. Medicine 96:51\u003c/span\u003e\u003c/li\u003e\u003c/ol\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":"Laminoplasty, Floating lamina, Re-close of lamina, Pseudarthrosis of the lateral gutter","lastPublishedDoi":"10.21203/rs.3.rs-6504824/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6504824/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe patient was a 68-year-old man who presented with myelopathy caused by a floating lamina resulting from pseudoarthrosis at the lateral gutter and reclosure of the lamina following cervical laminoplasty. Intraoperatively, the C2 and C3 laminae were found to be mobile. To avoid spinal cord injury, the laminae were stabilized using forceps while carefully drilling them with a high-speed burr under spinal cord monitoring. Scar tissue was removed, and the dural sac was decompressed. The patient\u0026rsquo;s symptoms improved early after surgery. It has been reported that medial deviation of the lateral gutter can result in insufficient spinal cord decompression and increased damage to the inner cortex of the lamina, which can lead to pseudoarthrosis and subsequent reclosure of the lamina. In the present case, there was no evidence of kyphotic deformity or spinal instability. However, the initial surgery involved a narrow lateral gutter, which likely led to gradual reclosure of the lamina. Osteophyte formation due to pseudoarthrosis at the lateral gutter also contributed to the recurrence of myelopathy.\u003c/p\u003e","manuscriptTitle":"A clinical experience in treating myelopathy caused by floating lamina resulting from re-close of the lamina and pseudarthrosis at the lateral gutter after cervical laminoplasty.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-25 06:24:48","doi":"10.21203/rs.3.rs-6504824/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":"1a395f8f-be38-40c1-904d-6e89dddd8bd5","owner":[],"postedDate":"June 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-07-31T07:54:07+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-25 06:24:48","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6504824","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6504824","identity":"rs-6504824","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}