Comparison of Postoperative Complications and Outcomes in Anterior Cervical Spine Surgery: Ossification of the Posterior Longitudinal Ligament Versus Cervical Spondylotic Myelopathy.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To compare the frequency of complications and outcomes between patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine and those with cervical spondylotic myelopathy (CSM) who underwent anterior surgery. SUMMARY OF BACKGROUND DATA: Anterior cervical spine surgery for OPLL is an effective surgical procedure; however, it is complex and technically demanding compared with the procedure for CSM. Few reports have compared postoperative complications and clinical outcomes after anterior surgeries between the 2 pathologies. METHODS: Among 1434 patients who underwent anterior cervical spine surgery at 3 spine centers within the same spine research group from January 2011 to March 2021, 333 patients with OPLL and 488 patients with CSM were retrospectively evaluated. Demographics, postoperative complications, and outcomes were reviewed by analyzing medical records. In-hospital and postdischarge postoperative complications were investigated. Postoperative outcomes were evaluated 1 year after the surgery using the Japanese Orthopaedic Association score. RESULTS: Patients with OPLL had more comorbid diabetes mellitus preoperatively than patients with CSM ( P <0.001). Anterior cervical corpectomies were more often performed in patients with OPLL than in those with CSM (73.3% and 14.5%). In-hospital complications, such as reoperation, cerebrospinal fluid leak, C5 palsy, graft complications, hoarseness, and upper airway complications, occurred significantly more often in patients with OPLL. Complications after discharge, such as complications of the graft bone/cage and hoarseness, were significantly more common in patients with OPLL. The recovery rate of the Japanese Orthopaedic Association score 1 year postoperatively was similar between patients with OPLL and those with CSM. CONCLUSION: The present study demonstrated that complications, both in-hospital and after discharge following anterior spine surgery, occurred more frequently in patients with OPLL than in those with CSM.

Predictors of good outcome after anterior decompression and fusion in patients with ossification of the posterior longitudinal ligament of the thoracic spine.

BACKGROUND: There are few reports concerning determinants of the surgical outcome of anterior decompression and fusion (ADF) when performed for ossification of the posterior longitudinal ligament of the thoracic spine (T-OPLL). We investigated prognostic factors associated with neurological recovery in the patients with T-OPLL. METHODS: This retrospective study included consecutive cases of T-OPLL patients from January 2002 to January 2020 and minimum one-year follow-up. Data were collected for sex, age, body mass index, preoperative manual muscle test score for the weakest muscle, surgical data, and preoperative and postoperative findings on radiographs, magnetic resonance images, and computed tomography scans. Imaging data were also collected, including preoperative kyphotic angles, canal occupancy ratio, type of OPLL, and high-intensity areas on T2-weighted images. The Japanese Orthopaedic Association score for thoracic myelopathy (T-JOA) was used to evaluate the recovery of the thoracic myelopathy. The patients were categorized according to whether the improvement in T-JOA score was >50% or ≤50%. RESULTS: Forty-six patients who underwent anterior procedures for T-OPLL were included in the study. Preoperative and postoperative T-JOA scores were 4.2 ± 2.3 and 7.9 ± 2.1, respectively. The improvement in the T-JOA score was 54.5 ± 25.6%. The proportion of patients with beak-type OPLL was significantly higher in the >50% JOA improvement group (23/27) than in the ≤50% group (9/19) (p = 0.009) and the canal occupancy ratio was significantly lower in the >50% group (56.3 ± 12.2% vs 64.4 ± 8.73%; p = 0.0163). There were no significant between-group differences in other factors. CONCLUSIONS: Beak-type ossification and a low canal occupancy ratio are predictors of good outcome after ADF in patients with T-OPLL. ADF should be considered in patients with either or both of these features.

Surgical outcomes of the thoracic ossification of ligamentum flavum: a retrospective analysis of 61 cases.

BACKGROUND: Thoracic ossification of ligamentum flavum (T-OLF), as one of the causes of thoracic myelopathy, is often combined with other spinal disorders. Concurrent lumbar spinal canal stenosis (LCS) is often obscured by symptoms due to T-OLF, leading to difficulty in identifying the origin of these neurological findings. It is common to be misdiagnosed or delayed diagnosis due to the complicated nature. We evaluated the prevalence, distribution, and clinical characteristics of OLF, especially in patients with LCS. METHODS: The authors performed a retrospective analysis of the outcomes of 61 patients who underwent thoracic surgeries performed for symptomatic T-OLF. In all the patients, whole spine lesions were evaluated preoperatively. We examined the factors related to poor outcomes (the recovery rate of the Japanese Orthopedic Association score for thoracic myelopathy is less than 40%) following OLF surgeries. We compared the clinical outcomes according to whether there was concurrent LCS, and determined the optimal surgical approach. RESULTS: The occurrence of T-OLF increased with age. Forty-six cases (75.4%) were considered to be tandem T-OLF and LCS (LCS group). An advanced age, and concurrent LCS were associated with a poor outcome after the surgery. The LCS group significantly included a greater number of elderly, and more light-weighted patients with Modic change in thoracic spine and a greater sagittal vertical axis, resulting in the lower neurological recovery. Additional lumbar surgery (13cases) effectively improved both the T-JOA and L-JOA scores (from 6.5 ± 2.0 points to 8.0 ± 1.8 points, p = 0.0406, and from 14.5 ± 4.7 points to 20.7 ± 2.6 points, p = 0.001, respectively) in OLF patients with LCS. CONCLUSIONS: T-OLF was highly associated with other spinal disorders. Poor outcomes in T-OLF surgery could be associated with age and concurrent LCS, and an additional surgery for another lumbar lesion significantly improved neurological findings in T-OLF patients.

Pedicle Subtraction Osteotomy for Kyphosis Following Lumbar Fusion Surgery.

INTRODUCTION: Pedicle subtraction osteotomy (PSO) is performed to correct sagittal plane deformity. This procedure is useful with revision cases in which the number of intact discs for correction is limited. METHODS: Forty-four patients (10 male and 34 female) with minimum follow-up of 2 years were reviewed; all had undergone PSO revision surgery for kyphosis following previous lumbar fusion surgery. The average age at operation was 72.8 years (range 42-85 years), and the average follow-up period was 4.1 years (2-9 years). The average fusion level was 7.5 (4-13 level), and the average previously fused level was 2.4 (1-7 level). RESULTS: The average operation time was 424 min, and average blood loss was 2880 g. The average JOA score of 14.0 before operation changed to 21.8 at 1-year follow-up and to 20.7 at final follow-up. The average recovery rate at final follow-up was 45.7%. Four patients underwent re-operations for proximal junctional kyphosis and 3 patients for rod fracture. The fusion rate was 88.6%, and 13 patients (29.5%) developed subsequent vertebral fracture. The average PI-LL (Pelvic incidence minus Lumbar lordosis) at pre-op of 52.9 degrees changed to 3.8 degrees at post-op, to 13.4 degrees at 1-year follow-up, and to 14.8 degrees at final follow-up. The average correction at the PSO site was 36.0 degrees at post-op, 36.7 degrees at 1-year follow-up, and 37.0 degrees at final follow-up. The average sagittal vertical axis at pre-op of 145.0 mm decreased to 51.2 mm at 1-year follow-up; however, it increased to 75.3 mm at final follow-up. CONCLUSION: PSO for correction of kyphosis following previous lumbar fusion surgery was an effective procedure without correction loss at the local osteotomy site; however, its surgical invasiveness and complication rate were high. Subsequent vertebral fracture, adjacent segment degeneration, and rod fracture contribute to deterioration of outcome that is evident at long-term follow-up.