Anterior-Only Decompression Fails in Multisegmental Concentric Stenosis: Indicators for Secondary Posterior Surgery

Anterior-Only Decompression Fails in Multisegmental Concentric Stenosis: Indicators for Secondary Posterior Surgery | 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 Research Article Anterior-Only Decompression Fails in Multisegmental Concentric Stenosis: Indicators for Secondary Posterior Surgery Yazan Noufal, Marcus Richter, Philipp Hartung, Philipp Drees, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6648160/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 : The compression of the spinal cord can result in degenerative cervical myelopathy (DCM), a condition characterized by progressive neurological dysfunction. This study examines clinical outcomes after anterior decompression and predictors of secondary posterior decompression after initial anterior surgery. Methods : In this retrospective single-center study, 94 patients who underwent anterior cervical decompression between 2020 and 2024 were analyzed. Demographic, clinical (e.g., Japanese Orthopaedic Association (JOA) score, American Society of Anesthesiologists (ASA) classification), and radiological parameters (stenosis type, number of levels involved, spinal cord shift) were collected. Multivariable logistic regression analysis, likelihood ratio model and Mann-Whitney-U-Test were employed to identify independent predictors for the necessity of a secondary posterior decompression. Results : In nine patients (9.5 %), secondary posterior decompression was necessary. All of these patients presented with preoperative concentric stenosis, representing 20.1 % of that subgroup. Patients with a concentric stenosis significantly presented with lower JOA scores (12.4 ± 2.7) than patients with a non-concentric stenosis (14.1 ± 1.9). Non-concentric stenosis was associated with a markedly lower reoperation likelihood (p = 0.019). Sequential likelihood-ratio showed that besides concentric-stenosis, a multisegmental pathology increased the probability of a secondary posterior surgery. In addition, patients that required secondary surgery had a significantly smaller anterior epidural space after first anterior decompression. Conclusions : Preoperative multisegmental concentric stenosis significantly predicted secondary posterior decompression. In addition, postoperative limited anterior epidural space highlights that ventral decompression alone inadequately addresses circumferential compression. Degenerative cervical myelopathy 7-Letter-Code Cervical spinal canal stenosis Myelon shifting Figures Figure 1 Introduction Degenerative cervical myelopathy (DCM) is a degenerative condition resulting in a variety of neurological symptoms: gait disorder, fine motor impairment, sensory deficits, and muscle weakness [ 1 – 4 ]. Common cause is a cervical spinal canal stenosis caused by structural changes such as disc degeneration, osteophyte formation, ossification of the posterior longitudinal ligament (OPLL) [ 5 ] or hypertrophy of the ligamenta flava. The narrowing of the spinal canal can be either anterior, posterior, or antero-posterior (concentric)[ 6 ]. In concentric stenoses, the spinal cord is compressed from both sides, which can significantly impair neurological function. In more acute cases, patients may present with an acute traumatic central cord syndrome (ATCCS), a condition often resulting from sudden trauma or overextension of the cervical spine [ 7 ]. In this study, we aim to analyze the clinical outcomes and identify the predictors for the need of a secondary posterior decompression following an initial anterior surgical approach in patients with central cervical spinal canal stenosis. By focusing on preoperative factors such as the severity of DCM, the type of spinal cord compression, and the application of the 7-Letter Code, we seek to provide insights into optimizing surgical decision-making and improving patient outcomes. Materials and Methods Ethical approval The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the ethics committee Ethikkommission Landesärztekammer Hessen, application number 2025-3982-evBO. As this study is retrospective in nature a need for informed consent was waived by the ethics committee. Data collection In this retrospective study, we collected data from our clinic who underwent anterior decompression of the cervical spine between 2020 and 2024. The data was extracted from the intrahospital information system (ORBIS, Agfa Healthcare GmbH, Bonn, Germany). Patients were eligible for inclusion if they had a central cervical spinal canal stenosis, diagnosed DCM and were above 18 years of age. Exclusion criteria included cases of purely foraminal stenosis (nerve root compression without central canal compromise), acute trauma, infection, or neoplasms. Patients were followed-up 3- and 12-months after anterior surgery. The posterior surgeries were performed at a median of 1.5 months (range 0.5–7 months) after the initial anterior surgery and were also followed-up 3- and 12-months after surgery. Data that was analyzed included demographic variables, American Society of Anesthesiologists (ASA) classification, clinical neurological dysfunction (e.g., muscle weakness, paresthesia, JOA score (Japanese Orthopaedic Association score)), and radiological parameters such as the type of stenosis and sagittal parameters, and the extent of spinal cord shift after surgery observed on MRI. The measurements of radiographic images were done by a senior and a junior spine surgeon. Figure 1 shows the measurement of anterior and posterior epidural space. Statistical Analysis The present assessments were performed using computer-assisted analyses. The necessary programming was performed in the R language using the R software package available on the Comprehensive R Archive Network (CRAN) at https://cran.r-project.org and Microsoft Excel. Data were analyzed with Mann-Whitney-U-Test, univariate and multivariable logistic regression, and likelihood-ratio. Statistical significance was defined p < 0.05. Results Ninety-four patients met inclusion criteria during the study period. The mean age was 62.4 ± 12.3 years, and 41% (39/94) of patients were female. The mean JOA score was 14.1 ± 1.9 for the cohort which was operated from anterior only (anterior—surgery-only-cohort or ASC); while the other cohort (which was also operated from posterior; combined-surgery-cohort or CSC) had a mean JOA score of was 12.4 ± 2.7. Radiologically, 38 patients (40.4 %) had stenosis primarily from anterior structures, no patients had solely posterior compression ,13 patients (13.8 %) had a “hill-type” compression (e.g. ventral compression from one side), and 43 patients (45.8 %) had circumferential stenosis. One-level disease was present in 47 patients, two-level in 37, and three-level in 10 patients. Notably, there was a significant association between stenosis morphology and preoperative JOA score with non-concentric cases averaging 14.4 ± 1.8 versus 12.4 ± 2.1 in concentric cases (p = 0.027). Nine patients (9/95, 9.5%) required a secondary posterior decompression due to persistent or recurrent stenosis causing persisting myelopathic symptoms. All nine cases occurred in patients with a concentric stenosis representing 20.1% (9/43) of that subgroup. A Firth‐bias-reduced logistic regression was used to assess the effect of stenosis type (non-concentric (ventral and hill-type) vs. concentric) on the odds of secondary surgery. Non-concentric stenosis was associated with a markedly lower likelihood of dorsal revision than concentric stenosis (Firth‐adjusted OR 0.032, 95 % CI 0.002–0.569; p = 0.019). Table 1 summarizes the results of sequential likelihood-ratio tests for nested logistic-regression models predicting secondary posterior surgery. Starting from a base model that included only stenosis morphology (concentric vs. non-concentric), we added predictors one at a time—in the order: number of segments, JOA score, ASA score, patient age, and BMI. Only the addition of the number of segments significantly improved model fit (p= 0.048); none of the subsequently added clinical variables yielded a statistically significant benefit (all p > 0.05). Table 1. Sequential likelihood-ratio for predicting secondary posterior surgery Step Predictor added p-value Base Concentric stenosis 1 Number of Segments (per number) 0.048 2 Preoperative JOA score (per unit) 0.16 3 ASA score (per unit) 0.24 4 Age (years) 0.56 5 BMI (kg/m ²) 0.9 Table 1. Sequential likelihood ratio for predicting the necessity of secondary posterior decompression. Abbreviations: ASA – American Society of Anesthesiologists; JOA score – Japanese Orthopaedic Association score; BMI – body mass index. In addition, in an univariate logistic regression model, each one‐point decrease in preoperative JOA score was associated with a significantly higher likelihood of requiring secondary posterior decompression among patients with DCM (p = 0.03). However, when implementing a firth‐penalized multivariate logistic regression model, each one‐point increase in the preoperative JOA score was associated with a nonsignificant 21 % reduction in the odds of requiring revision (OR 0.79, 95 % CI 0.58–1.08; p = 0.14). These findings indicate that stenosis type and the number of segments —but not the JOA score per se—drives the risk of subsequent posterior decompression. After anterior decompression: in the CSC, the mean anterior and posterior epidural space were below our measurement resolution (nominally calculated as 0.16 and 0.22 mm, respectively). In the ASC the mean anterior and posterior epidural space was 1.6 and 0.6 mm, respectively. The difference in anterior epidural space between the two cohorts was highly significant (p = 0.00035), whereas posterior epidural space did not differ significantly (p = 0.2092). The posterior surgeries were laminectomies with instrumented fusion in all nine cases, performed at a median of 1.5 months (range 0.5–7 months) after the initial anterior surgery. No intraoperative complications occurred during or after the posterior surgeries. After secondary surgery, the mean JOA score improved to 14.4 at 3-months follow-up and 14.7 at 12-months follow-up. Discussion Our analysis demonstrates that patients presenting with preoperative multisegmental concentric stenosis face a markedly increased likelihood of requiring secondary posterior decompression following initial anterior cervical surgery. These findings align closely with Papavero et al.’s 7-Letter-Code, which stratifies cervical stenosis patterns to guide surgical approach selection [6]. It has been developed as a standardized system for classifying the anatomical features of cervical stenosis. This tool is intended to help surgeons determine the most effective surgical approach—whether an anterior, a posterior, or a combined procedure. In this system, multisegmental concentric stenoses call for a combined anterior–posterior strategy, given that ventral decompression alone may leave significant dorsal compression unaddressed. Our data validate this recommendation by illustrating that an anterior-only approach fails to restore sufficient spinal canal patency in multisegmental concentric cases, precipitating symptomatic persistence and the need for reintervention. Moreover, a lower preoperative JOA score was associated with higher revision rates in univariate logistic regression (p = 0.03), although this lost statistical significance in multivariate logistic regression (p = 0.14), underscoring stenosis morphology as the primary driver of reoperation risk as well as of a lower JOA score. The prognostic relevance of baseline neurological status, as measured by the JOA score, is well documented. Tetreault et al. systematically reviewed outcomes in degenerative cervical myelopathy and identified lower preoperative JOA scores as independent predictors of poorer functional recovery, emphasizing the importance of early intervention in patients with severe myelopathy [8]. In our study, although the JOA score did not retain significance in adjusted analysis, its univariate association suggests that patients with advanced neurological impairment warrant particular attention during preoperative planning. Radiological evaluation of postoperative epidural space further demonstrate the shortcomings of anterior-only decompression in concentric stenosis. Postoperative MRI revealed that patients requiring secondary posterior decompression had persisting spinal canal stenosis. This highlights that anterior decompression alone inadequately addresses circumferential compression, leaving the spinal cord tethered posteriorly. Our results corroborate earlier work by Alafifi et al., who identified combined anterior and posterior compressive pathology on MRI as a predictor of suboptimal outcomes following surgical intervention for DCM [9]. Limitations Our results must be viewed considering certain limitations. First, the study is retrospective in nature with a relatively small number of revision events (n=9), which limits the statistical power, especially for multivariate analysis. Finally, being a single-center study, the surgical techniques and threshold for reoperation may not be generalizable to other settings. Conclusion Preoperative multisegmental concentric stenosis significantly predicted secondary posterior decompression. In addition, postoperative limited anterior epidural space highlights that anterior decompression alone inadequately addresses circumferential compression. Declarations Funding This research received no external funding. Conflict of Interest The authors declare no conflict of interest. Data availability statement All data analyzed during this study are included in the Supplementary Information files. Author Contribution YN- information retrieval, data analysis, conceptualization and design of study, conceptualization of the figures, interpretation of the results, writing of the manuscript.MR- initiation of the project, supervision of the data acquisition, conceptualization and design of study, interpretation of the results, writing of the manuscript, critical revision of the manuscript for important intellectual content.PH - critical revision of the manuscript for important intellectual content.PD - critical revision of the manuscript for important intellectual content.YA - critical revision of the manuscript for important intellectual content.MN- supervision of the data acquisition, interpretation of the results, writing of the manuscript, critical revision of the manuscript for important intellectual content References Davies BM, Mowforth OD, Smith EK, Kotter MRN (2018) Degenerative cervical myelopathy. BMJ (Online) 360:. https://doi.org/10.1136/bmj.k186 Toledano M, Bartleson JD (2013) Cervical Spondylotic Myelopathy. Neurol Clin 31:287–305. https://doi.org/10.1016/j.ncl.2012.09.003 Bernhardt M, Hynes RA, Blume HW, White AA (1993) Current concepts review. Cervical spondylotic myelopathy. Journal of Bone and Joint Surgery - Series A 75:119–129. https://doi.org/10.2106/00004623-199301000-00016 Hai-bin C, Zheng-guo W, Ling Z, et al (2012) Cervical spinal canal narrowing and cervical neurological injuries. Chinese Journal of Traumatology - English Edition 15:36–41. https://doi.org/10.3760/cma.j.issn.1008-1275.2012.01.008 Lee NJ, Boddapati V, Mathew J, et al (2023) What Is the Impact of Surgical Approach in the Treatment of Degenerative Cervical Myelopathy in Patients With OPLL? A Propensity-Score Matched, Multi-Center Analysis on Inpatient and Post-Discharge 90-Day Outcomes. Global Spine J 13:324–333. https://doi.org/10.1177/2192568221994797 Papavero L, Schmeiser G, Kothe R, et al (2020) Degenerative Cervical Myelopathy: A 7-Letter Coding System That Supports Decision-Making for the Surgical Approach. Neurospine 17:164–171. https://doi.org/10.14245/NS.1938010.005 Zhou Q, Zhang J, Liu H, et al (2022) Comparison of Anterior and Posterior Approaches for Acute Traumatic Central Spinal Cord Syndrome with Multilevel Cervical Canal Stenosis without Cervical Fracture or Dislocation. Int J Clin Pract 2022:5132134. https://doi.org/10.1155/2022/5132134 Tetreault LA, Karpova A, Fehlings MG (2015) Predictors of outcome in patients with degenerative cervical spondylotic myelopathy undergoing surgical treatment: results of a systematic review. Eur Spine J 24 Suppl 2:236–251. https://doi.org/10.1007/S00586-013-2658-Z Alafifi T, Kern R, Fehlings M (2007) Clinical and MRI predictors of outcome after surgical intervention for cervical spondylotic myelopathy. J Neuroimaging 17:315–322. https://doi.org/10.1111/J.1552-6569.2007.00119.X Additional Declarations No competing interests reported. Supplementary Files DataavailabilityPredictors.xlsx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-6648160","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":457869309,"identity":"55791a32-1f3e-4bba-b886-c80dad9c3897","order_by":0,"name":"Yazan Noufal","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuElEQVRIiWNgGAWjYLCCCgYLOcYGHiCLjVgtZxgkjEnXktjAQKwWg9vNxyQO1EikN7f3HnzAUGZDhJY7x9IkDhyTyG3sOZdswHAujQgtN3LMpD+wAbXMyDGTYGw7TJwWiQP/JNIZIVr+E6nlYJtEAlTLAcJaJG+kJVsc7JMwbOw5Y2yQcC6ZsBa+G8kHbxz4ZiNv2N5j+OBDmR1hLQowlxg2AIkEwhoYGOQbYAxiVI+CUTAKRsHIBAC9qzszFpaLNwAAAABJRU5ErkJggg==","orcid":"","institution":"St. Josefs Hospital","correspondingAuthor":true,"prefix":"","firstName":"Yazan","middleName":"","lastName":"Noufal","suffix":""},{"id":457869310,"identity":"76427958-4fe4-4a09-92f9-b4c878bfddbc","order_by":1,"name":"Marcus Richter","email":"","orcid":"","institution":"St. Josefs Hospital","correspondingAuthor":false,"prefix":"","firstName":"Marcus","middleName":"","lastName":"Richter","suffix":""},{"id":457869311,"identity":"0932bdd8-08f8-4c8e-a61e-229d366fb766","order_by":2,"name":"Philipp Hartung","email":"","orcid":"","institution":"St. Josefs Hospital","correspondingAuthor":false,"prefix":"","firstName":"Philipp","middleName":"","lastName":"Hartung","suffix":""},{"id":457869312,"identity":"25c0cae0-bc00-4f5e-a550-3b2c2a220982","order_by":3,"name":"Philipp Drees","email":"","orcid":"","institution":"Johannes Gutenberg University Mainz","correspondingAuthor":false,"prefix":"","firstName":"Philipp","middleName":"","lastName":"Drees","suffix":""},{"id":457869313,"identity":"5d54d99c-4cbf-4bc3-b0b3-9df7915e8675","order_by":4,"name":"Yama Afghanyar","email":"","orcid":"","institution":"Johannes Gutenberg University Mainz","correspondingAuthor":false,"prefix":"","firstName":"Yama","middleName":"","lastName":"Afghanyar","suffix":""},{"id":457869314,"identity":"5f18089d-1bfc-4753-b031-391ddf78e584","order_by":5,"name":"Martin Naisan","email":"","orcid":"","institution":"St. Josefs Hospital","correspondingAuthor":false,"prefix":"","firstName":"Martin","middleName":"","lastName":"Naisan","suffix":""}],"badges":[],"createdAt":"2025-05-12 15:38:22","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6648160/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6648160/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83213227,"identity":"c7ae75c3-e7bc-4841-8017-7134eb8c89d7","added_by":"auto","created_at":"2025-05-21 08:43:35","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":288067,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eAnterior epidural space is measured by the distance from the approximated anterior limitation of the myelon to the anterior spinal canal. Posterior epidural space is measured by the distance from the approximated posterior limitation of the myelon to the posterior spinal canal. a) preoperative, b) postoperative, blue arrows show anterior and posterior epidural space.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6648160/v1/10d29cba7e51ffb36b394e8d.png"},{"id":86807445,"identity":"27ba4dbb-d91d-40a9-b44d-c781fc049c1a","added_by":"auto","created_at":"2025-07-15 18:46:35","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":812112,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6648160/v1/e10aadf4-8fde-4496-96cf-8e0f55c3f6f8.pdf"},{"id":83213228,"identity":"0c29aed5-fb92-4e1b-8ba4-0ee1588fe5c9","added_by":"auto","created_at":"2025-05-21 08:43:35","extension":"xlsx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":27749,"visible":true,"origin":"","legend":"","description":"","filename":"DataavailabilityPredictors.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-6648160/v1/af0fa40ab4b8d91a242e70b0.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Anterior-Only Decompression Fails in Multisegmental Concentric Stenosis: Indicators for Secondary Posterior Surgery","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDegenerative cervical myelopathy (DCM) is a degenerative condition resulting in a variety of neurological symptoms: gait disorder, fine motor impairment, sensory deficits, and muscle weakness [\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Common cause is a cervical spinal canal stenosis caused by structural changes such as disc degeneration, osteophyte formation, ossification of the posterior longitudinal ligament (OPLL) [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] or hypertrophy of the ligamenta flava. The narrowing of the spinal canal can be either anterior, posterior, or antero-posterior (concentric)[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn concentric stenoses, the spinal cord is compressed from both sides, which can significantly impair neurological function.\u003c/p\u003e \u003cp\u003eIn more acute cases, patients may present with an acute traumatic central cord syndrome (ATCCS), a condition often resulting from sudden trauma or overextension of the cervical spine [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn this study, we aim to analyze the clinical outcomes and identify the predictors for the need of a secondary posterior decompression following an initial anterior surgical approach in patients with central cervical spinal canal stenosis. By focusing on preoperative factors such as the severity of DCM, the type of spinal cord compression, and the application of the 7-Letter Code, we seek to provide insights into optimizing surgical decision-making and improving patient outcomes.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003ch2\u003eEthical approval\u003c/h2\u003e\n\u003cp\u003eThe study was conducted according to the guidelines of the Declaration of Helsinki and approved by the ethics committee Ethikkommission Landes\u0026auml;rztekammer Hessen, application number 2025-3982-evBO. As this study is retrospective in nature a need for informed consent was waived by the ethics committee.\u003c/p\u003e\n\u003ch2\u003eData collection\u003c/h2\u003e\n\u003cp\u003eIn this retrospective study, we collected data from our clinic who underwent anterior decompression of the cervical spine between 2020 and 2024. The data was extracted from the intrahospital information system (ORBIS, Agfa Healthcare GmbH, Bonn, Germany). Patients were eligible for inclusion if they had a central cervical spinal canal stenosis, diagnosed DCM and were above 18 years of age. Exclusion criteria included cases of purely foraminal stenosis (nerve root compression without central canal compromise), acute trauma, infection, or neoplasms.\u003c/p\u003e\n\u003cp\u003ePatients were followed-up 3- and 12-months after anterior surgery. The posterior surgeries were performed at a median of 1.5 months (range 0.5\u0026ndash;7 months) after the initial anterior surgery and were also followed-up 3- and 12-months after surgery.\u003c/p\u003e\n\u003cp\u003eData that was analyzed included demographic variables, American Society of Anesthesiologists (ASA) classification, clinical neurological dysfunction (e.g., muscle weakness, paresthesia, JOA score (Japanese Orthopaedic Association score)), and radiological parameters such as the type of stenosis and sagittal parameters, and the extent of spinal cord shift after surgery observed on MRI.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe measurements of radiographic images were done by a senior and a junior spine surgeon. Figure 1 shows the measurement of anterior and posterior epidural space.\u003c/p\u003e\n\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\n\u003cp\u003eThe present assessments were performed using computer-assisted analyses. The necessary programming was performed in the R language using the R software package available on the Comprehensive R Archive Network (CRAN) at https://cran.r-project.org and Microsoft Excel. Data were analyzed with Mann-Whitney-U-Test, univariate and multivariable logistic regression, and likelihood-ratio. Statistical significance was defined p \u0026lt; 0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eNinety-four patients met inclusion criteria during the study period. The mean age was 62.4 \u0026plusmn; 12.3 years, and 41% (39/94) of patients were female.\u003c/p\u003e\n\u003cp\u003eThe mean JOA score was 14.1 \u0026plusmn; 1.9 for the cohort which was operated from anterior only (anterior\u0026mdash;surgery-only-cohort or ASC); while the other cohort (which was also operated from posterior; combined-surgery-cohort or CSC) had a mean JOA score of was 12.4 \u0026plusmn; 2.7.\u003c/p\u003e\n\u003cp\u003eRadiologically, 38 patients (40.4 %) had stenosis primarily from anterior structures, no patients had solely posterior compression ,13 patients (13.8 %) \u0026nbsp;had a \u0026ldquo;hill-type\u0026rdquo; compression (e.g. ventral compression from one side), and 43 patients (45.8 %) had circumferential stenosis.\u003c/p\u003e\n\u003cp\u003eOne-level disease was present in 47 patients, two-level in 37, and three-level in 10 patients.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNotably, there was a significant association between stenosis morphology and preoperative JOA score with non-concentric cases averaging 14.4 \u0026plusmn; 1.8 versus 12.4 \u0026plusmn; 2.1 in concentric cases (p = 0.027).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNine patients (9/95, 9.5%) required a secondary posterior decompression due to persistent or recurrent stenosis causing persisting myelopathic symptoms. \u0026nbsp;All nine cases occurred in patients with a concentric stenosis representing 20.1% (9/43) of that subgroup.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA Firth‐bias-reduced logistic regression was used to assess the effect of stenosis type (non-concentric (ventral and hill-type) vs. concentric) on the odds of secondary surgery. Non-concentric stenosis was associated with a markedly lower likelihood of dorsal revision than concentric stenosis (Firth‐adjusted OR 0.032, 95 % CI 0.002\u0026ndash;0.569; p = 0.019).\u003c/p\u003e\n\u003cp\u003eTable 1 summarizes the results of sequential likelihood-ratio tests for nested logistic-regression models predicting secondary posterior surgery. Starting from a base model that included only stenosis morphology (concentric vs. non-concentric), we added predictors one at a time\u0026mdash;in the order: number of segments, JOA score, ASA score, patient age, and BMI. Only the addition of the number of segments significantly improved model fit (p= 0.048); none of the subsequently added clinical variables yielded a statistically significant benefit (all p \u0026gt; 0.05).\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 595px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 1. Sequential likelihood-ratio for predicting secondary posterior surgery\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStep\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 350px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePredictor added\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003eBase\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 350px;\"\u003e\n \u003cp\u003eConcentric stenosis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 350px;\"\u003e\n \u003cp\u003eNumber of Segments (per number)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.048\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 350px;\"\u003e\n \u003cp\u003ePreoperative JOA score (per unit)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.16\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 350px;\"\u003e\n \u003cp\u003eASA score (per unit)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.24\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 350px;\"\u003e\n \u003cp\u003eAge (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.56\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 350px;\"\u003e\n \u003cp\u003eBMI (kg/m \u0026sup2;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eTable 1. Sequential likelihood ratio for predicting the necessity of secondary posterior decompression. Abbreviations: ASA \u0026ndash; American Society of Anesthesiologists; JOA score \u0026ndash; Japanese Orthopaedic Association score; BMI \u0026ndash; body mass index.\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eIn addition, in an univariate logistic regression model, each one‐point decrease in preoperative JOA score was associated with a significantly higher likelihood of requiring secondary posterior decompression among patients with DCM (p = 0.03). However, when implementing a firth‐penalized multivariate logistic regression model, each one‐point increase in the preoperative JOA score was associated with a nonsignificant 21 % reduction in the odds of requiring revision (OR 0.79, 95 % CI 0.58\u0026ndash;1.08; p = 0.14).\u003c/p\u003e\n\u003cp\u003eThese findings indicate that stenosis type and the number of segments \u0026mdash;but not the JOA score per se\u0026mdash;drives the risk of subsequent posterior decompression.\u003c/p\u003e\n\u003cp\u003eAfter anterior decompression: in the CSC, the mean anterior and posterior epidural space were below our measurement resolution (nominally calculated as 0.16 and 0.22 mm, respectively). In the ASC the mean anterior and posterior epidural space was 1.6 and 0.6 mm, respectively. The difference in anterior epidural space between the two cohorts was highly significant (p = 0.00035), whereas posterior epidural space did not differ significantly (p = 0.2092).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe posterior surgeries were laminectomies with instrumented fusion in all nine cases, performed at a median of 1.5 months (range 0.5\u0026ndash;7 months) after the initial anterior surgery.\u003c/p\u003e\n\u003cp\u003eNo intraoperative complications occurred during or after the posterior surgeries.\u003c/p\u003e\n\u003cp\u003eAfter secondary surgery, the mean JOA score improved to 14.4 at 3-months follow-up and 14.7 at 12-months follow-up.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eOur analysis demonstrates that patients presenting with preoperative multisegmental concentric stenosis face a markedly increased likelihood of requiring secondary posterior decompression following initial anterior cervical surgery.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThese findings align closely with Papavero et al.\u0026rsquo;s 7-Letter-Code, which stratifies cervical stenosis patterns to guide surgical approach selection [6].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIt has been developed as a standardized system for classifying the anatomical features of cervical stenosis. This tool is intended to help surgeons determine the most effective surgical approach\u0026mdash;whether\u0026nbsp;an anterior,\u0026nbsp;a posterior, or\u0026nbsp;a combined procedure.\u003c/p\u003e\n\u003cp\u003eIn this system, multisegmental concentric stenoses call for a combined anterior\u0026ndash;posterior strategy, given that ventral decompression alone may leave significant dorsal compression unaddressed. Our data validate this recommendation by illustrating that an anterior-only approach fails to restore sufficient spinal canal patency in multisegmental concentric cases, precipitating symptomatic persistence and the need for reintervention.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMoreover, a lower preoperative JOA score was associated with higher revision rates in univariate logistic regression (p = 0.03), although this lost statistical significance in multivariate logistic regression (p = 0.14), underscoring stenosis morphology as the primary driver of reoperation risk as well as of a lower JOA score.\u003c/p\u003e\n\u003cp\u003eThe prognostic relevance of baseline neurological status, as measured by the JOA score, is well documented. Tetreault et al. systematically reviewed outcomes in degenerative cervical myelopathy and identified lower preoperative JOA scores as independent predictors of poorer functional recovery, emphasizing the importance of early intervention in patients with severe myelopathy [8]. In our study, although the JOA score did not retain significance in adjusted analysis, its univariate association suggests that patients with advanced neurological impairment warrant particular attention during preoperative planning.\u003c/p\u003e\n\u003cp\u003eRadiological evaluation of postoperative epidural space further demonstrate the shortcomings of anterior-only decompression in concentric stenosis. Postoperative MRI revealed that patients requiring secondary posterior decompression had persisting spinal canal stenosis. This highlights that anterior decompression alone inadequately addresses circumferential compression, leaving the spinal cord tethered posteriorly.\u003c/p\u003e\n\u003cp\u003eOur results corroborate earlier work by Alafifi et al., who identified combined anterior and posterior compressive pathology on MRI as a predictor of suboptimal outcomes following surgical intervention for DCM [9].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLimitations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOur results must be viewed considering certain limitations. First, the study is retrospective in nature with a relatively small number of revision events (n=9), which limits the statistical power, especially for multivariate analysis. Finally, being a single-center study, the surgical techniques and threshold for reoperation may not be generalizable to other settings.\u0026nbsp;\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003ePreoperative multisegmental concentric stenosis significantly predicted secondary posterior decompression. In addition, postoperative limited anterior epidural space highlights that anterior decompression alone inadequately addresses circumferential compression.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no external funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data analyzed during this study are included in the Supplementary Information files.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eYN- information retrieval, data analysis, conceptualization and design of study, conceptualization of the figures, interpretation of the results, writing of the manuscript.MR- initiation of the project, supervision of the data acquisition, conceptualization and design of study, interpretation of the results, writing of the manuscript, critical revision of the manuscript for important intellectual content.PH - critical revision of the manuscript for important intellectual content.PD - critical revision of the manuscript for important intellectual content.YA - critical revision of the manuscript for important intellectual content.MN- supervision of the data acquisition, interpretation of the results, writing of the manuscript, critical revision of the manuscript for important intellectual content\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eDavies BM, Mowforth OD, Smith EK, Kotter MRN (2018) Degenerative cervical myelopathy. BMJ (Online) 360:. https://doi.org/10.1136/bmj.k186\u003c/li\u003e\n\u003cli\u003eToledano M, Bartleson JD (2013) Cervical Spondylotic Myelopathy. Neurol Clin 31:287\u0026ndash;305. https://doi.org/10.1016/j.ncl.2012.09.003\u003c/li\u003e\n\u003cli\u003eBernhardt M, Hynes RA, Blume HW, White AA (1993) Current concepts review. Cervical spondylotic myelopathy. Journal of Bone and Joint Surgery - Series A 75:119\u0026ndash;129. https://doi.org/10.2106/00004623-199301000-00016\u003c/li\u003e\n\u003cli\u003eHai-bin C, Zheng-guo W, Ling Z, et al (2012) Cervical spinal canal narrowing and cervical neurological injuries. Chinese Journal of Traumatology - English Edition 15:36\u0026ndash;41. https://doi.org/10.3760/cma.j.issn.1008-1275.2012.01.008\u003c/li\u003e\n\u003cli\u003eLee NJ, Boddapati V, Mathew J, et al (2023) What Is the Impact of Surgical Approach in the Treatment of Degenerative Cervical Myelopathy in Patients With OPLL? A Propensity-Score Matched, Multi-Center Analysis on Inpatient and Post-Discharge 90-Day Outcomes. Global Spine J 13:324\u0026ndash;333. https://doi.org/10.1177/2192568221994797\u003c/li\u003e\n\u003cli\u003ePapavero L, Schmeiser G, Kothe R, et al (2020) Degenerative Cervical Myelopathy: A 7-Letter Coding System That Supports Decision-Making for the Surgical Approach. Neurospine 17:164\u0026ndash;171. https://doi.org/10.14245/NS.1938010.005\u003c/li\u003e\n\u003cli\u003eZhou Q, Zhang J, Liu H, et al (2022) Comparison of Anterior and Posterior Approaches for Acute Traumatic Central Spinal Cord Syndrome with Multilevel Cervical Canal Stenosis without Cervical Fracture or Dislocation. Int J Clin Pract 2022:5132134. https://doi.org/10.1155/2022/5132134\u003c/li\u003e\n\u003cli\u003eTetreault LA, Karpova A, Fehlings MG (2015) Predictors of outcome in patients with degenerative cervical spondylotic myelopathy undergoing surgical treatment: results of a systematic review. Eur Spine J 24 Suppl 2:236\u0026ndash;251. https://doi.org/10.1007/S00586-013-2658-Z\u003c/li\u003e\n\u003cli\u003eAlafifi T, Kern R, Fehlings M (2007) Clinical and MRI predictors of outcome after surgical intervention for cervical spondylotic myelopathy. J Neuroimaging 17:315\u0026ndash;322. https://doi.org/10.1111/J.1552-6569.2007.00119.X\u003c/li\u003e\n\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":"Degenerative cervical myelopathy, 7-Letter-Code, Cervical spinal canal stenosis, Myelon shifting","lastPublishedDoi":"10.21203/rs.3.rs-6648160/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6648160/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e: The compression of the spinal cord can result in degenerative cervical myelopathy (DCM), a condition characterized by progressive neurological dysfunction.\u003c/p\u003e\n\u003cp\u003eThis study examines clinical outcomes after anterior decompression and predictors of secondary posterior decompression after initial anterior surgery.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e: In this retrospective single-center study, 94 patients who underwent anterior cervical decompression between 2020 and 2024 were analyzed. Demographic, clinical (e.g., Japanese Orthopaedic Association (JOA) score, American Society of Anesthesiologists (ASA) classification), and radiological parameters (stenosis type, number of levels involved, spinal cord shift) were collected. Multivariable logistic regression analysis, likelihood ratio model and Mann-Whitney-U-Test were employed to identify independent predictors for the necessity of a secondary posterior decompression.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e: In nine patients (9.5 %), secondary posterior decompression was necessary. All of these patients presented with preoperative concentric stenosis, representing 20.1 % of that subgroup. Patients with a concentric stenosis significantly presented with lower JOA scores (12.4 ± 2.7) than patients with a non-concentric stenosis (14.1 ± 1.9).\u003c/p\u003e\n\u003cp\u003eNon-concentric stenosis was associated with a markedly lower reoperation likelihood (p = 0.019). Sequential likelihood-ratio showed that besides concentric-stenosis, a multisegmental pathology increased the probability of a secondary posterior surgery.\u003c/p\u003e\n\u003cp\u003eIn addition, patients that required secondary surgery had a significantly smaller anterior epidural space after first anterior decompression.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e: Preoperative multisegmental concentric stenosis significantly predicted secondary posterior decompression. In addition, postoperative limited anterior epidural space highlights that ventral decompression alone inadequately addresses circumferential compression.\u003c/p\u003e","manuscriptTitle":"Anterior-Only Decompression Fails in Multisegmental Concentric Stenosis: Indicators for Secondary Posterior Surgery","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-21 08:43:31","doi":"10.21203/rs.3.rs-6648160/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":"ee579623-0c59-48e3-a3d6-d1258fac61e4","owner":[],"postedDate":"May 21st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-07-15T18:38:28+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-21 08:43:31","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6648160","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6648160","identity":"rs-6648160","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}