Abstract
Purpose
The motion at the non-ossified segment of the ossification of the posterior longitudinal ligament (OPLL) is thought to be highly correlated to aggravation of symptoms of myelopathy. The rationale for posterior decompression with instrumented fusion (PDF) surgery is to limit the motion of the non-ossified segment of OPLL by stabilization. The purpose of the present study was to elucidate the course of bone union and remodelling of the non-ossified segment of thoracic OPLL (T-OPLL) after PDF surgery.
Methods
A total of 29 patients who underwent PDF surgery for T-OPLL were included in this study. We measured the thickness of the OPLLs by determining the thickest part of the OPLL in the sagittal multi-planer reconstruction CT images pre- and post-operatively. Five experienced spine surgeons independently performed CT measurements of OPLL thickness twice. Japanese Orthopaedic Association score for thoracic myelopathy was measured as clinical outcome measure.
Results
Non-ossified segment of OPLLs fused in 24 out of 29 (82.8 %) patients. The average thickness of the OPLL at its thickest segment was 8.0 mm and decreased to 7.3 mm at final follow-up. The decrease in ossification thickness was significantly larger in the patients who showed fusion of non-ossified segments of OPLL compared with that in the patients did not show fusion. There was no significant correlation between the clinical outcome and the decrease in thickness of the OPLLs.
Conclusion
The results of this study showed that remodelling of the OPLLs, following fusion of non-ossified segment of OPLLs, resulted in a decreased OPLL thickness, with potential for a reduction of spinal cord compression.
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References
Smith ZA, Buchanan CC, Raphael D et al (2011) Ossification of the posterior longitudinal ligament: pathogenesis, management, and current surgical approaches. A review. Neurosurg Focus 30:E10
Kawaguchi Y, Matsumoto M, Iwasaki M et al (2014) New classification system for ossification of the posterior longitudinal ligament using CT images. J Orthop Sci 19:530–536
Fujiyoshi T, Yamazaki M, Okawa A et al (2010) Static versus dynamic factors for the development of myelopathy in patients with cervical ossification of the posterior longitudinal ligament. J Clin Neurosci 17:320–324
Matsumoto M, Chiba K, Toyama Y et al (2008) Surgical results and related factors for ossification of posterior longitudinal ligament of the thoracic spine: a multi-institutional retrospective study. Spine 33:1034–1041
Yamazaki M, Mochizuki M, Ikeda Y et al (2006) Clinical results of surgery for thoracic myelopathy caused by ossification of the posterior longitudinal ligament: operative indication of posterior decompression with instrumented fusion. Spine 31:1452–1460
Matsuyama Y, Sakai Y, Katayama Y et al (2009) Indirect posterior decompression with corrective fusion for ossification of the posterior longitudinal ligament of the thoracic spine: is it possible to predict the surgical results? Eur Spine J 18:943–948
Kimura H, Fujibayashi S, Takemoto M et al (2014) Spontaneous reduction in ossification of the posterior longitudinal ligament of the thoracic spine after posterior spinal fusion without decompression: a case report. Spine 39:E417–E419
Sakou T, Hirabayashi K (1994) Modified criteria of patient selection for treatment of ossification of spinal ligaments. Annual report of taskforce of research for ossification of spinal ligaments sponsored by the Japanese Ministry of Health and Welfare, pp 11–14 (in Japanese)
Matsumoto M, Toyama Y, Chikuda H et al (2011) Outcomes of fusion surgery for ossification of the posterior longitudinal ligament of the thoracic spine: a multicenter retrospective survey. J Neurosurg Spine 15:380–385
Hirabayashi K, Miyakawa J, Satomi K et al (1981) Operative results and postoperative progression of ossification among patients with ossification of cervical posterior longitudinal ligament. Spine 6:354–364
Kudo H, Yokoyama T, Tsushima E et al (2013) Interobserver and intraobserver reliability of the classification and diagnosis for ossification of the posterior longitudinal ligament of the cervical spine. Eur Spine J 22:205–210
Sjöström L, Jacobsson O, Karlström G et al (1994) Spinal canal remodelling after stabilization of thoracolumbar burst fractures. Eur Spine J 3:312–317
Miyashita T, Ataka H, Tanno T (2013) Spontaneous reduction of a floated ossification of the ligamentum flavum after posterior thoracic decompression (floating method); report of a case (abridged translation of a primary publication). Spine J 13:e7–e9
Yamazaki M, Okawa A, Fujiyoshi T et al (2010) Posterior decompression with instrumented fusion for thoracic myelopathy caused by ossification of the posterior longitudinal ligament. Eur Spine J 19:691–698
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Koda, M., Furuya, T., Okawa, A. et al. Bone union and remodelling of the non-ossified segment in thoracic ossification of the posterior longitudinal ligament after posterior decompression and fusion surgery. Eur Spine J 24, 2555–2559 (2015). https://doi.org/10.1007/s00586-015-3888-z
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DOI: https://doi.org/10.1007/s00586-015-3888-z