Anterior Direct Decompression Significantly Relieves Spinal Cord High Signal in Patients with Ossification of the Posterior Longitudinal Ligament: a Case-control Study

Overview

Journal J Orthop Surg Res

Publisher Biomed Central

Specialty Orthopedics

Date 2023 Nov 24

PMID 38001479

Authors

Zichuan Wu

Zifan Zhang

Aochen Xu

Shihao Lu

Cheng Cui

Baifeng Sun

Yang Liu

Affiliations

Soon will be listed here.

Abstract

Background: In patients with cervical spondylotic myelopathy caused by ossification of the posterior longitudinal ligament, high cord signal (HCS) is frequently observed. However, limited research has investigated the variations in HCS improvement resulting from different surgical approaches. This study aims to explore the potential relationship between the choice of surgical approach and the postoperative improvement of intramedullary high signal in ossification of the posterior longitudinal ligament (OPLL) patients.

Methods: We extensively reviewed the patients' medical records, based on which demographic information such as gender, age, and body mass index (BMI) were recorded, and assessed the severity of the patients' neurological status preoperatively and postoperatively by using the Japanese Orthopedic Association score (JOAs), focusing on consecutive preoperative and postoperative Magnetic resonance imaging (MRI) T2WI measurements, to study the statistical correlation between the improvement of HCS and the choice of surgical approach.

Results: There were no significant differences in demographic, imaging parameters, and clinical symptoms between patients undergoing anterior and posterior surgery (p > 0.05, Table 1). However, both improvement in JOAs (Recovery2) and improvement in HCS (CR2) were significantly better in the anterior surgery group two years after surgery (p < 0.05, Table 1). Multifactorial logistic regression analysis revealed that posterior surgery and higher preoperative signal change ratio (SCR) were identified as risk factors for poor HCS improvement at the two-year postoperative period (p < 0.05, Table 2). Table 1 Differences in demographic, imaging parameters, and clinical symptoms in patients with anterior and posterior approach Anterior approach Posterior approach P-Values Demographic data Sex (male/female) 10/12 6/17 0.175 Age 58.59 ± 5.68 61.43 ± 9.04 0.215 Hypertension 14/8 14/9 0.848 Diabetes 16/6 19/4 0.425 BMI 25.58 ± 4.72 26.95 ± 4.58 0.331 Smoking history 19/3 16/7 0.175 Preoperative measured imaging parameters Preoperative SCR 1.615 ± 0.369 1.668 ± 0.356 0.623 CR1 0.106 ± 0.125 0.011 ± 0.246 0.08 CNR 0.33 ± 0.073 0.368 ± 0.096 0.15 C2-7 Cobb angle 8.977 ± 10.818 13.862 ± 13.191 0.182 SVA 15.212 ± 8.024 17.46 ± 8.91 0.38 mK-line INT 3.694 ± 3.291 4.527 ± 2.227 0.323 Imaging follow-up 6 months postoperative SCR 1.45 ± 0.44 1.63 ± 0.397 0.149 2 years postoperative SCR 1.26 ± 0.19 1.65 ± 0.35 0.000** CR2 0.219 ± 0.14 - 0.012 ± 0.237 0.000** Clinical symptoms Preoperative JOAs 10.64 ± 1.59 10.83 ± 1.47 0.679 6 months postoperative JOAs 11.82 ± 1.37 11.65 ± 1.4 0.69 2 years postoperative JOAs 14.18 ± 1.01 12.52 ± 2.06 0.001** Recovery1 0.181 ± 0.109 0.128 ± 0.154 0.189 Recovery2 0.536 ± 0.178 0.278 ± 0.307 0.001** , statistical significance (p < 0.05). **, statistical significance (p < 0.01) BMI = body mass index. SCR = the signal change ratio between the localized high signal and normal spinal cord signal at the C7-T1 levels. CR1 = the regression of high cord signals at 6 months postoperatively (i.e., CR1 = (Preoperative SCR-SCR at 6 months postoperatively)/ Preoperative SCR). CR2 = the regression of high cord signal at 2 years postoperatively (i.e., CR2 = (Preoperative SCR-SCR at 2 years postoperatively)/ Preoperative SCR). CNR = canal narrowing ratio. SVA = sagittal vertical axis. mK-line INT = modified K-line interval. JOAs = Japanese Orthopedic Association score. Recovery1 = degree of JOAs recovery at 6 months postoperatively (i.e., Recover1 = (JOAs at 6 months postoperatively-Preoperative JOAs)/ (17- Preoperative JOAs)). Recovery2 = degree of JOAs recovery at 2 years postoperatively (i.e., Recover2 = (JOAs at 2 years postoperatively-Preoperative JOAs)/ (17-Preoperative JOAs)) Table 2 Linear regression analyses for lower CR2 values 95% CI P value Uni-variable analyses Demographic data Sex (male/female) - 0.01 0.221 0.924 Age - 0.015 0.003 0.195 Hypertension - 0.071 0.204 0.334 Diabetes - 0.195 0.135 0.716 BMI - 0.375 0.422 0.905 Smoking history - 0.249 0.077 0.295 Surgical approach - 0.349 - 0.113 0.000 Preoperative measured imaging parameters C2-7 Cobb angle - 0.009 0.002 0.185 SVA - 0.008 0.008 0.995 mK-line INT - 0.043 0.005 0.122 Preoperative SCR 0.092 0.445 0.004 CR1 0.156 0.784 0.004 CNR - 0.76 0.844 0.918 Multi-variable analyses Surgical approach - 0.321 - 0.118 0.000** Preoperative SCR 0.127 0.41 0.000** CR1 - 0.018 0.501 0.067 , variables that achieved a significance level of p < 0.1 in the univariate analysis *statistical significance (p < 0.05). **statistical significance (p < 0.01) BMI = body mass index. SCR = the signal change ratio between the localized high signal and normal spinal cord signal at the C7-T1 levels. CR1 = the regression of high cord signals at 6 months postoperatively (i.e., CR1 = (Preoperative SCR-SCR at 6 months postoperatively)/ Preoperative SCR). CR2 = the regression of high cord signal at 2 years postoperatively (i.e., CR2 = (Preoperative SCR-SCR at 2 years postoperatively)/ Preoperative SCR). CNR = canal narrowing ratio. SVA = sagittal vertical axis. mK-line INT = modified K-line interval CONCLUSIONS: For patients with OPLL-induced cervical spondylotic myelopathy and intramedullary high signal, anterior removal of the ossified posterior longitudinal ligament and direct decompression offer a greater potential for regression of intramedullary high signal. At the same time, this anterior surgical strategy improves clinical neurologic function better than indirect decompression in the posterior approach.

References

Chen Y, Liu X, Chen D, Wang X, Yuan W . Surgical strategy for ossification of the posterior longitudinal ligament in the cervical spine. Orthopedics. 2012; 35(8):e1231-7. DOI: 10.3928/01477447-20120725-25. View

Li J, Yang Z, Xie T, Song Z, Song Y, Zeng J . Deterioration of the fixation segment's stress distribution and the strength reduction of screw holding position together cause screw loosening in ALSR fixed OLIF patients with poor BMD. Front Bioeng Biotechnol. 2022; 10:922848. PMC: 9468878. DOI: 10.3389/fbioe.2022.922848. View

Fujimori T, Iwasaki M, Okuda S, Takenaka S, Kashii M, Kaito T . Long-term results of cervical myelopathy due to ossification of the posterior longitudinal ligament with an occupying ratio of 60% or more. Spine (Phila Pa 1976). 2013; 39(1):58-67. DOI: 10.1097/BRS.0000000000000054. View

Ito K, Imagama S, Ito K, Ito Z, Ando K, Kobayashi K . MRI Signal Intensity Classification in Cervical Ossification of the Posterior Longitudinal Ligament: Predictor of Surgical Outcomes. Spine (Phila Pa 1976). 2016; 42(2):E98-E103. DOI: 10.1097/BRS.0000000000001717. View

Mastronardi L, ELsawaf A, Roperto R, Bozzao A, Caroli M, Ferrante M . Prognostic relevance of the postoperative evolution of intramedullary spinal cord changes in signal intensity on magnetic resonance imaging after anterior decompression for cervical spondylotic myelopathy. J Neurosurg Spine. 2007; 7(6):615-22. DOI: 10.3171/SPI-07/12/615. View

Wang L, Zhang Y, Shen Y, Su Y, Xu J, Ding W . Using the T2-weighted magnetic resonance imaging signal intensity ratio and clinical manifestations to assess the prognosis of patients with cervical ossification of the posterior longitudinal ligament. J Neurosurg Spine. 2010; 13(3):319-23. DOI: 10.3171/2010.3.SPINE09887. View

Shin J, Jin B, Kim K, Cho Y, Cho W . Intramedullary high signal intensity and neurological status as prognostic factors in cervical spondylotic myelopathy. Acta Neurochir (Wien). 2010; 152(10):1687-94. DOI: 10.1007/s00701-010-0692-8. View

Matsunaga S, Sakou T . Ossification of the posterior longitudinal ligament of the cervical spine: etiology and natural history. Spine (Phila Pa 1976). 2011; 37(5):E309-14. DOI: 10.1097/BRS.0b013e318241ad33. View

Li J, Zhang Z, Xie T, Song Z, Song Y, Zeng J . The preoperative Hounsfield unit value at the position of the future screw insertion is a better predictor of screw loosening than other methods. Eur Radiol. 2022; 33(3):1526-1536. PMC: 9935714. DOI: 10.1007/s00330-022-09157-9. View

10.

Qin R, Chen X, Zhou P, Li M, Hao J, Zhang F . Anterior cervical corpectomy and fusion versus posterior laminoplasty for the treatment of oppressive myelopathy owing to cervical ossification of posterior longitudinal ligament: a meta-analysis. Eur Spine J. 2018; 27(6):1375-1387. DOI: 10.1007/s00586-017-5451-6. View

11.

Machino M, Ando K, Kobayashi K, Ito K, Tsushima M, Morozumi M . Alterations in Intramedullary T2-weighted Increased Signal Intensity following Laminoplasty in Cervical Spondylotic Myelopathy Patients: Comparison Between Pre- and Postoperative Magnetic Resonance Images. Spine (Phila Pa 1976). 2018; 43(22):1595-1601. DOI: 10.1097/BRS.0000000000002674. View

12.

Fernandez de Rota J, Meschian S, Fernandez de Rota A, Urbano V, Baron M . Cervical spondylotic myelopathy due to chronic compression: the role of signal intensity changes in magnetic resonance images. J Neurosurg Spine. 2007; 6(1):17-22. DOI: 10.3171/spi.2007.6.1.4. View

13.

Zhang Y, Shen Y, Wang L, Ding W, Xu J, He J . Magnetic resonance T2 image signal intensity ratio and clinical manifestation predict prognosis after surgical intervention for cervical spondylotic myelopathy. Spine (Phila Pa 1976). 2010; 35(10):E396-9. DOI: 10.1097/BRS.0b013e3181c6dbc4. View

14.

Liu X, Min S, Zhang H, Zhou Z, Wang H, Jin A . Anterior corpectomy versus posterior laminoplasty for multilevel cervical myelopathy: a systematic review and meta-analysis. Eur Spine J. 2013; 23(2):362-72. PMC: 3906468. DOI: 10.1007/s00586-013-3043-7. View

15.

Lee J, Lee N, Oh S, Shin D, Yi S, Kim K . Clinical and radiological outcomes of multilevel cervical laminoplasty versus three-level anterior cervical discectomy and fusion in patients with cervical spondylotic myelopathy. Quant Imaging Med Surg. 2020; 10(11):2112-2124. PMC: 7547256. DOI: 10.21037/qims-20-220. View

16.

Chen X, Shan T, Li Y . Prognostic effect of increased postoperative MRI T2WI high signal intensity in degenerative cervical myelopathy. Spine J. 2022; 22(12):1964-1973. DOI: 10.1016/j.spinee.2022.07.097. View

17.

An H, Al-Shihabi L, Kurd M . Surgical treatment for ossification of the posterior longitudinal ligament in the cervical spine. J Am Acad Orthop Surg. 2014; 22(7):420-9. DOI: 10.5435/JAAOS-22-07-420. View

18.

Suri A, Chabbra R, Mehta V, Gaikwad S, Pandey R . Effect of intramedullary signal changes on the surgical outcome of patients with cervical spondylotic myelopathy. Spine J. 2003; 3(1):33-45. DOI: 10.1016/s1529-9430(02)00448-5. View

19.

Xu P, Zhuang J, Huang Y, Chen J, Zhong Z . Is anterior decompression and fusion superior to laminoplasty for cervical myelopathy due to ossification of posterior longitudinal ligament? A systematic review and meta-analysis. J Spinal Cord Med. 2019; 44(2):169-183. PMC: 7952055. DOI: 10.1080/10790268.2019.1579987. View

20.

Nouri A, Tetreault L, Singh A, Karadimas S, Fehlings M . Degenerative Cervical Myelopathy: Epidemiology, Genetics, and Pathogenesis. Spine (Phila Pa 1976). 2015; 40(12):E675-93. DOI: 10.1097/BRS.0000000000000913. View