木村 敦

STUDY DESIGN: A prospective multicenter study. OBJECTIVE: To investigate the effect of preoperative symptom duration on neurological recovery for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL). SUMMARY OF BACKGROUND DATA: The optimal timing to perform surgery in the setting of cervical OPLL remains unknown. It is important to know the influence of symptom duration on postoperative outcomes to facilitate discussions regarding the timing of surgery. PATIENTS AND METHODS: The study included 395 patients (291 men and 104 women; mean age, 63.7 ± 11.4 yr): 204 were treated with laminoplasty, 90 with posterior decompression and fusion, 85 with anterior decompression and fusion, and 16 with other procedures. The Japanese Orthopedic Association (JOA) score and patient-reported outcomes of the JOA Cervical Myelopathy Evaluation Questionnaire were used to assess clinical outcomes preoperatively and 2 years after surgery. Logistic regression analysis was used to identify factors associated with the achievement of minimum clinically important difference (MCID) after surgery. RESULTS: The recovery rate was significantly lower in the group with symptom duration of ≥5 years compared with the groups with durations of <0.5 years, 0.5 to 1 year, and 1 to 2 years. Improvement of JOA Cervical Myelopathy Evaluation Questionnaire in the upper extremity function score ( P < 0.001), lower extremity function ( P = 0.039), quality of life ( P = 0.053), and bladder function ( P = 0.034) were all decreased when the symptom duration exceeded 2 years. Duration of symptoms ( P = 0.001), age ( P < 0.001), and body mass index ( P < 0.001) were significantly associated with the achievement of MCID. The cutoff value we established for symptom duration was 23 months (area under the curve, 0.616; sensitivity, 67.4%; specificity, 53.5%). CONCLUSIONS: Symptom duration had a significant impact on neurological recovery and patient-reported outcome measures in this series of patients undergoing surgery for cervical OPLL. Patients with symptom duration exceeding 23 months may be at greater risk of failing to achieve MCID after surgery. LEVEL OF EVIDENCE: 3.

STUDY DESIGN: A prospective multicenter study. OBJECTIVE: To investigate the incidence of loss of cervical lordosis after laminoplasty for cervical ossification of the posterior longitudinal ligament (OPLL). We also sought to determine associated risk factors and the relationship with patient-reported outcomes. SUMMARY OF BACKGROUND DATA: Loss of cervical lordosis is a sequalae often observed after laminoplasty, which may adversely impact surgical outcomes. Cervical kyphosis, especially in OPLL, is associated with reoperation, but risk factors and relationship to postoperative outcomes remain understudied at this time. METHODS: This study was conducted by the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament. We included 165 patients who underwent laminoplasty and completed Japanese Orthopaedic Association (JOA) score or Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaires (JOACMEQ), as well as visual analog scales (VAS) for pain, with imaging. The participants were divided into two groups: those with loss of cervical lordosis of>10° or 20° after surgery and those without loss of cervical lordosis. A paired t-test was applied to evaluate the association between changes in cervical spinal angles, ROM, and cervical JOA and VAS scores before and at 2 years postoperatively. Mann-Whitney U-test was used for JOACMEQ. RESULTS: Postoperative loss of cervical lordosis>10° and>20° was observed in 32 (19.4%) and 7 (4.2%), respectively. JOA, JOACMEQ, and VAS scores were not significantly different between those with, and without, loss of cervical lordosis. Preoperative small extension range of motion (eROM) was significantly associated with postoperative loss of cervical lordosis, and the cutoff values of eROM were 7.4° [area under the curve (AUC): 0.76] and 8.2° (AUC: 0.92) for loss of cervical lordosis>10° and>20°, respectively. A large occupation ratio of OPLL was also associated with loss of cervical lordosis, with a cutoff value of 39.9% (AUC: 0.94). Laminoplasty resulted in functional improvement in most patient-reported outcomes; however, neck pain and bladder function tended to become worse postoperatively in cases with postoperative loss of cervical lordosis>20°. CONCLUSION: JOA, JOACMEQ, and VAS scores were not significantly different between those with, and without, loss of cervical lordosis. Preoperative small eROM and large OPLL may represent factors associated with loss of cervical lordosis after laminoplasty in patients with OPLL.

BACKGROUND: The incidence of spinal cord injury without radiological abnormality (SCIWORA) is increasing among older adults in developed countries. SCIWORA is commonly associated with ossification of the spinal ligament, specifically the ossification of the posterior longitudinal ligament (OPLL) and ossification of the anterior longitudinal ligament (OALL). OALL induces segmental spinal fusion and alters the biomechanical properties of the cervical spine; however, whether OALL modulates the severity of SCIWORA remains unknown. This study aimed to investigate the influence of OALL on the severity and distribution of neurological deficits following SCIWORA. METHODS: This retrospective study included 122 patients with SCIWORA who were admitted to our hospital from April 2008 to March 2022. The neurological function of all the included patients was assessed via the American Spinal Injury Association (ASIA) Impairment Scale (AIS) at admission. Magnetic resonance imaging (MRI) and computed tomography were performed within 48 h of trauma. Central cord syndrome (CCS) was defined as the upper-extremity ASIA motor score being at least 10 points lesser than the lower-extremity motor score. RESULTS: The study included 122 patients with a mean age of 65.1 years. Comparing mild (AIS grades C or D) and severe (AIS grades A or B) neurological deficits revealed that the former was independently associated with ground-level falls, OALL, and absence of prevertebral T2 high-intensity area on MRI. Although 39% of patients with SCIWORA exhibited OPLL as an etiology of cervical stenosis, OPLL demonstrated no significant effect on the severity of neurological deficits. CCS occurrence was independently associated with OALL and a larger cross-sectional cord area on MRI. Patients with OALL had significantly higher lower-extremity ASIA motor scores than those without OALL. CONCLUSIONS: OALL was significantly associated with mild neurological deficits in the lower extremities and with the occurrence of CCS after SCIWORA.

STUDY DESIGN: A prospective multicenter study. OBJECTIVE: To compare the surgical outcomes of anterior and posterior fusion surgeries in patients with K-line (-) cervical ossification of the posterior longitudinal ligament (OPLL). SUMMARY OF BACKGROUND DATA: Although laminoplasty is effective for patients with K-line (+) OPLL, fusion surgery is recommended for those with K-line (-) OPLL. However, whether the anterior or posterior approach is preferable for this pathology has not been effectively determined. METHODS: A total of 478 patients with myelopathy due to cervical OPLL from 28 institutions were prospectively registered from 2014 to 2017 and followed up for 2 years. Of the 478 patients, 45 and 46 with K-line (-) underwent anterior and posterior fusion surgeries, respectively. After adjusting for confounders in baseline characteristics using a propensity score-matched analysis, 54 patients in both the anterior and posterior groups (27 patients each) were evaluated. Clinical outcomes were assessed using the cervical Japanese Orthopaedic Association and the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire. RESULTS: Both approaches showed comparable neurological and functional recovery. The cervical range of motion was significantly restricted in the posterior group because of the large number of fused vertebrae compared with the anterior group. The incidence of surgical complications was comparable between the cohorts, but the posterior group demonstrated a higher frequency of segmental motor paralysis, whereas the anterior group more frequently reported postoperative dysphagia. CONCLUSION: Clinical improvement was comparable between anterior and posterior fusion surgeries for patients with K-line (-) OPLL. The ideal surgical approach should be informed based on the balance between the surgeon's technical preference and the risk of complications.