Comparison of Range of Motion Outcomes in Patients Undergoing Open-Door Laminoplasty or Posterior Cervical Fusion Surgery for Cervical Spondylotic Myelopathy

Context: Considerable controversy exists over surgical procedures for ossification of the posterior longitudinal ligament (OPLL). Objective: The purpose of the meta-analysis was to compare the clinical outcome of anterior decompression and fusion (ADF) with laminoplasty (LAMP) in treatment of cervical myelopathy due to OPLL. Methods: PubMed, EMBASE and the Cochrane Register of Controlled Trials database were searched to identify potential clinical studies compared ADF with LAMP for cervical myelopathy owing to OPLL. We also manually searched the reference lists of articles and reviews for possible relevant studies. Thirteen studies with 1120 patients were included in our analysis. Subgroup analyses were performed by the canal occupying ratio of OPLL. Results: Overall, the mean preoperative Japanese Orthopaedic Association (JOA) score was similar between two groups. Compared with LAMP group, ADF group was higher at the mean postoperative JOA scores and mean recovery rate, reoperation rate, and longer at mean operation time. There was not significantly different in mean blood loss and complication rate between two groups. In subgroup analysis, ADF had a higher mean postoperative JOA score and recovery rate than LAMP in cases of OPLL with occupying ratios ≥ 50%, while those difference were not found in cases of OPLL with occupying ratios < 50%. Conclusion: ADF achieves better neurological improvement compared with LAMP in treatment of cervical myelopathy due to OPLL, especially in cases of OPLL with occupying ratios ≥ 50%. Complication rate is similar between two groups, but ADF can increase the risk of reoperation

A retrospective study of the long-term results from double-door laminoplasty (Kurokawa's method) for patients with myelopathy caused by ossification of the posterior longitudinal ligament and cervical spondylosis was performed. To know whether the short-term results from double-door laminoplasty were maintained over a 10-year period and, if not, the cause of late deterioration. There are few long-term follow-up studies on the outcome of laminoplasty for cervical stenotic myelopathy. In this study, 35 patients with cervical myelopathy caused by ossification of the posterior longitudinal ligament in the cervical spine and 25 patients with cervical spondylotic myelopathy, including 5 patients with athetoid cerebral palsy, underwent double-door laminoplasty from 1980 through 1988 and were followed over the next 10 years. The average follow-up period was 153 months (range, 120-200 months) in patients with ossification of the posterior longitudinal ligament and 156 months (range, 121-218 months) in patients with cervical spondylotic myelopathy. Neurologic deficits before and after surgery were assessed using a scoring system proposed by the Japanese Orthopedic Association (JOA score). Patients who showed late deterioration received further examination including computed tomography scan and magnetic resonance imaging of the cervical spine. In 32 of the patients with ossification of the posterior longitudinal ligament and 23 of the patients with cervical spondylotic myelopathy, myelopathy improved after surgery. The improvement of Japanese Orthopedic Association scores was maintained up to the final follow-up assessment in 26 of the patients with ossification of the posterior longitudinal ligament and 21 of the patients with cervical spondylotic myelopathy. Late neurologic deterioration occurred in 10 of the patients with ossification of the posterior longitudinal ligament an average of 8 years after surgery, and in 4 of the patients with cervical spondylotic myelopathy, including the 3 patients with athetoid cerebral palsy, an average of 11 years after surgery. The main causes of deterioration in patients with ossification of the posterior longitudinal ligament were a minor trauma in patients with residual cervical cord compression caused by ossification of the posterior longitudinal ligament and thoracic myelopathy resulting from ossification of the yellow ligament in the thoracic spine. The short-term results of laminoplasty for cervical stenotic myelopathy were maintained over 10years in 78% of the patients with ossification of the posterior longitudinal ligament, and in most of the patients with cervical spondylotic myelopathy, except those with athetoid cerebral palsy. Double-door laminoplasty is a reliable procedure for individuals with cervical stenotic myelopathy.

This prospective multicenter study, established by the Japanese Ministry of Health, Labour and Welfare and involving 27 institutions, aimed to compare postoperative outcomes between laminoplasty (LM) and posterior fusion (PF) for cervical ossification of the posterior longitudinal ligament (OPLL), in order to address the controversy surrounding the role of instrumented fusion in cases of posterior surgical decompression for OPLL. 478 patients were considered for participation in the study; from among them, 189 (137 and 52 patients with LM and PF, respectively) were included and evaluated using the Japanese Orthopaedic Association (JOA) scores, the JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), and radiographical measurements. Basic demographic and radiographical data were reviewed, and the propensity to choose a surgical procedure was calculated. Preoperatively, there were no significant differences among the participants in terms of patient backgrounds, radiographical measurements (K-line or cervical alignment on X-ray, OPLL occupation ratio on computed tomography, increased signal intensity change on magnetic resonance imaging), or clinical status (JOA score and JOACMEQ) after adjustments. The overall risk of perioperative complications was found to be lower with LM (odds ratio [OR] 0.40, p = 0.006), and the rate of C5 palsy occurrence was significantly lower with LM (OR 0.11, p = 0.0002) than with PF. The range of motion (20.91° ± 1.05° and 9.38° ± 1.24°, p < 0.0001) in patients who had PF was significantly smaller than in those who had LM. However, multivariable logistic regression analysis showed no significant difference among the participants in JOA score, JOA recovery rate, or JOACMEQ improvement at two years. In contrast, OPLL progression was greater in the LM group than in the PF group (OR 2.73, p = 0.0002). Both LM and PF for cervical myelopathy due to OPLL had resulted in comparable postoperative outcomes at 2 years after surgery.

A retrospective observational study. To clarify the exceptional conditions for a favorable neurological recovery after laminoplasty (LMP) for cervical myelopathy caused by K-line (-) ossification of the posterior longitudinal ligament (OPLL). The K-line-based classification of cervical OPLL was developed to predict insufficient neurological recovery after LMP. For patients with K-line (-) OPLL, LMP generally yields the least improvement because of inadequate decompression of the spinal cord; however, there are some exceptional cases wherein LMP promotes favorable neurological recoveries. We retrospectively reviewed the medical records of 106 consecutive patients who underwent LMP for cervical OPLL to determine the demographic data, radiographic findings, and neurological recoveries of the patients as assessed preoperatively and 2 years postoperatively by their Japanese Orthopedic Association (JOA) scores. The factors associated with favorable outcomes after LMP in patients with K-line (-) were then investigated. Of 106 total patients, 31 were classified as K-line (-), of whom 21 achieved the least neurological recovery after LMP (JOA recovery rate <50%), while the remaining 10 patients achieved favorable outcomes (JOA recovery rate ≥50%). Among the K-line (-) group patients, those with ext-K-line (+), which changed to K-line (+) in the neck-extended position, and the patients with up-K-line (-), in whom the lesion responsible for myelopathy in the upper cervical spine (C3 or above), showed favorable neurological recoveries after LMP. Our data shows that, even for patients with K-line (-) OPLL, a favorable neurological recovery can be expected after LMP in cases in which the OPLL is in the upper cervical spine or the K-line changes to (+) in the neck-extended position. This means that K-line-based predictions of surgical outcomes after LMP should be indicated for patients with OPLL in the middle and lower cervical spine with limited extension mobility.Level of Evidence: 4.

Objective: Multilevel posterior cervical fusion (PCF) and decompression surgery is a viable treatment option for multilevel ossification of posterior longitudinal ligament (OPLL) and spondylotic myelopathy. Since OPLL is known to affect bone formation, this study aimed to examine the effect of OPLL on the incidence of pseudarthrosis following PCF in a cohort study. Methods: We conducted a retrospective cohort study of patients with PCF and laminectomy at our institution. This study included patients who underwent C3 to C6 posterior fusion surgery involving lateral mass screw fixation without anterior surgery for OPLL or spondylotic myelopathy. Fusion status was evaluated 1 year postoperatively with computed tomography. Bone mineral density (BMD) and sagittal parameters were also evaluated as potential contributing factors to the fusion rate.Results: Eighty patients were included. Pseudarthrosis was observed in 22.5% (n=18) of patients. Pseudarthrosis incidence was lower in patients with OPLL (spondylosis vs. OPLL, 33.3% vs. 12.2%; p=0.003), and a higher BMD T-score (pseudarthrosis vs. fusion, -1.9 ± 0.7 vs. -0.6 ± 1.3; p&lt;0.01), a larger preoperative range of motion (ROM) (26.7 ± 13.3 vs. 17.6 ± 10.9; p=0.01), and a greater preoperative-to-postoperative decrease in cervical lordosis (-8.1 ± 7.9 vs. -2.7 ± 7.9; p&lt;0.01). Pseudarthrosis was associated with worsening neck pain after surgery. Conclusion: The absence of OPLL, lower BMD, larger preoperative ROM, and a greater decrease in postoperative cervical lordosis were identified as risk factors for pseudarthrosis after multiple PCF.

Mechanical complications should be considered following the correction of multilevel posterior cervical instrumented fusion. This study aimed to investigate clinical data on the patients' pre- and postoperative cervical alignment in terms of the incidence of mechanical complications after multilevel posterior cervical instrumented fusion. Between January 2008 and December 2018, 156 consecutive patients who underwent posterior cervical laminectomy and instrumented fusion surgery of 4 or more levels and were followed up for more than 2 years were included in this study. Age, sex, bone mineral density (BMD), BMI, mechanical complications, and pre- and postoperative radiographic factors were analyzed using multivariate logistic regression analysis to investigate the factors related to mechanical complications. Of the 156 patients, 114 were men and 42 were women; the mean age was 60.38 years (range 25-83 years), and the mean follow-up duration of follow-up was 37.56 months (range 24-128 months). Thirty-seven patients (23.7%) experienced mechanical complications, and 6 of them underwent revision surgery. The significant risk factors for mechanical complications were low BMD T-score (-1.36 vs -0.58, p = 0.001), a large number of fused vertebrae (5.08 vs 4.54, p = 0.003), a large preoperative C2-7 sagittal vertical axis (SVA; 32.28 vs 23.24 mm, p = 0.002), and low preoperative C2-7 lordosis (1.85° vs 8.83°, p = 0.001). The clinical outcomes demonstrated overall improvement in both groups; however, the neck visual analog scale, Neck Disability Index, and Japanese Orthopaedic Association scores after surgery were significantly worse in the mechanical complication group compared with the group without mechanical complications. Low BMD, a large number of fused vertebrae, a large preoperative C2-7 SVA, and low C2-7 lordosis were significant risk factors for mechanical complications after posterior cervical fusion surgery. The results of this study could be valuable for preoperative counseling, medical treatment, or surgical planning when multilevel posterior cervical instrumented fusion surgery is performed.

The purpose of this research is to compare the clinical efficacy, postoperative complication and surgical trauma between anterior cervical corpectomy and fusion versus posterior laminoplasty for the treatment of oppressive myelopathy owing to cervical ossification of the posterior longitudinal ligament (OPLL). Systematic review and meta-analysis. An comprehensive search of literature was implemented in three electronic databases (Embase, Pubmed, and the Cochrane library). Randomized or non-randomized controlled studies published since January 1990 to July 2017 that compared anterior cervical corpectomy and fusion (ACCF) versus posterior laminoplasty (LAMP) for the treatment of cervical oppressive myelopathy owing to OPLL were acquired. Exclusion criteria were non-human studies, non-controlled studies, combined anterior and posterior operative approach, the other anterior or posterior approaches involving cervical discectomy and fusion and laminectomy with (or without) instrumented fusion, revision surgeries, and cervical myelopathy caused by cervical spondylotic myelopathy. The quality of the included articles was evaluated according to GRADE. The main outcome measures included: preoperative and postoperative Japanese Orthopedic Association (JOA) score; neuro-functional recovery rate; complication rate; reoperation rate; preoperative and postoperative C2-C7 Cobb angle; operation time and intraoperative blood loss; and subgroup analysis was performed according to the mean preoperative canal occupying ratio (Subgroup A:the mean preoperative canal occupying ratio <60%, and Subgroup B:the mean preoperative canal occupying ratio ≥60%). A total of 10 studies containing 735 patients were included in this meta-analysis. And all of the selected studies were non-randomized controlled trials with relatively low quality as assessed by GRADE. The results revealed that there was no obvious statistical difference in preoperative JOA score between the ACCF and LAMP groups in both subgroups. Also, in subgroup A (the mean preoperative canal occupying ratio <60%), no obvious statistical difference was observed in the postoperative JOA score and neurofunctional recovery rate between the ACCF and LAMP groups. But, in subgroup B (the mean preoperative canal occupying ratio ≥60%), the ACCF group illustrated obviously higher postoperative JOA score and neurofunctional recovery rate than the LAMP group (P<0.01, WMD 1.89 [1.50, 2.28] and P<0.01, WMD 24.40 [20.10, 28.70], respectively). Moreover, the incidence of both complication and reoperation was markedly higher in the ACCF group compared with LAMP group (P<0.05, OR 1.76 [1.05, 2.97] and P<0.05, OR 4.63 [1.86, 11.52], respectively). In addition, the preoperative cervical C2-C7 Cobb angle was obviously larger in the LAMP group compared with ACCF group (P<0.05, WMD -5.77 [-9.70, -1.84]). But no statistically obvious difference was detected in the postoperative cervical C2-C7 Cobb angle between the two groups. Furthermore, the ACCF group showed significantly more operation time as well as blood loss compared with LAMP group (P<0.01, WMD 111.43 [40.32,182.54], and P<0.01, WMD 111.32 [61.22, 161.42], respectively). In summary, when the preoperative canal occupying ratio<60%, no palpable difference was tested in postoperative JOA score and neurofunctional recovery rate. But, when the preoperative canal occupying ratio ≥60% ACCF was associated with better postoperative JOA score and the recovery rate of neurological function compared with LAMP. Synchronously, ACCF in the cure for cervical myelopathy owing to OPLL led to more surgical trauma and more incidence of complication and reoperation. On the other hand, LAMP had gone a diminished postoperative C2-C7 Cobb angle, that might be a cause of relatively higher incidence of postoperative late neurofunctional deterioration. In brief, when the preoperative canal occupying ratio <60%, LAMP seems to be effective and safe. However, when the preoperative canal occupying ratio ≥60%, we prefer to choose ACCF while complications could be controlled by careful manipulation and advanced surgical techniques. No matter which option you choose, benefits and risks ought to be balanced.

Study Design. Prospective multicenter cohort study. Objective. To compare surgical outcomes between patients with cervical spondylotic myelopathy (CSM) and those with ossification of the posterior longitudinal ligament (OPLL) who underwent cervical spine surgery. Summary of Background Data. Although both CSM and OPLL cause degenerative cervical myelopathy (DCM), they differ in anatomical and pathological characteristics. OPLL is more prevalent in East Asian populations and may present with distinct surgical challenges due to rigidity and multilevel ossification. Prior comparative studies were mostly retrospective with limited use of patient-reported outcome measures (PROMs), making it unclear whether disease etiology influences postoperative recovery. Methods. A total of 935 patients (725 with CSM and 210 with OPLL) who underwent cervical spine surgery at 10 high-volume centers in Japan were prospectively followed for 2 years. Clinical, surgical, and radiographic data were collected. Cervical alignment and range of motion were measured radiographically. Outcomes included the Japanese Orthopaedic Association (JOA) score, Visual Analog Scale (VAS), 36-Item Short Form Health Survey (SF-36), JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), and Neuropathic Pain Symptom Inventory (NPSI). General linear model analyses were used to adjust for potential confounding factors in the evaluation of these outcomes. Results. OPLL patients were younger, had higher body mass index, and more frequently required instrumented fusion and multilevel decompression. They exhibited lower pre- and postoperative cervical mobility and lordosis. However, both groups demonstrated similar improvements in JOA, VAS, SF-36, JOACMEQ, and NPSI scores at 2 years. Complication rates were comparable, and no progression of deformity or instability was observed. Although baseline PROMs were better in the OPLL group, postoperative outcomes were equivalent between the groups. Conclusions. Patients with CSM and OPLL achieved similarly favorable outcomes after cervical spine surgery. These findings support a unified surgical strategy for DCM, emphasizing functional severity rather than pathological subtype in clinical decision-making. Level of Evidence. II.

Objective To evaluate the CT imaging after laminoplasty for the patients with ossification of the posterior lon-gitudinal ligament (OPLL) of the cervical spine. Methods From June 2011 to June 2016, Retrospectively analyzed the data of OPLL patients who underwent posterior cervical open-door laminoplasty. There were 21 patients finally enrolled in this study, which consisted of 11 male and 10 female aging from 55-69, mean(61.48±4.29). The preoperative patients all had severe symp-toms of spinal compression. Collected the Japanese Orthopaedic Association Scores(JOA) Scores of all patients for gender, age, pre-operative and postoperative follow-up.The length, width and thickness of OPLL were measured by CT scan and two-dimensional re-construction of cervical spine during preoperative and follow-up, and the average progress rate was calculated. The relationship be-tween OPLL size before surgery and OPLL progress rate after surgery was analyzed. Results A total of 21 patients were included in this study, with an average age of 61.48±4.29 years-old. The mean follow-up time was 3.36±1.92 years. The JOA score of cervi-cal spine was 11.81±1.75 before operationand 14.43±1.69 at the last follow-up time (t=3.8, P<0.01). The progression rate of OPLL length, width and thickness was 3.54± 2.89 mm/year, 0.49± 0.52 mm/year and 0.34± 0.21 mm/year, respectively. Compared with the width and thickness, the average progress speed of the length was statistically significant (t=3.6, P=0.003; t= 3.8, P=0.002). The progression rate of the rostraland caudal of OPLL was 1.54 ±1.19 mm/year and 1.60±1.33 mm/year (t=0.1, P=0.559). Linear regression showed that OPLL length progression speed (mm)=0.05×preoperative length+1.23, R2=0.26 and P=0.02. Theprogres-sion rate of width and thickness of OPLL had no correlation with preoperative OPLL width and thickness. The progression rates of local, segmental, continuous, and mixed OPLL were 3.02±0.26 mm, 2.97±0.65 mm, 3.65±1.14 mm, and 3.82±1.27 mm per year. Conclusion The JOA score of the posterior open-door laminoplasty of the cervical OPLL patients was significantly improved dur-ing a short-term follow up. CT imaging follow-up showed there was progression of OPLL in length, width and thickness, and the progression rate of length was faster than width and thickness. However, there was no significant difference between the progres-sion of rostral and caudal of OPLL. In addition, short-term follow-up showed a positive correlation between the progression rate of OPLL length and the length of OPLL preoperation.The progress rate of mixed and continuous OPLL may be greater than that of seg-mental and limited OPLL. Key words: Cervical vertebrae; Ossification of posterior longitudinal ligament; Tomography, spiral computed; Follow-up studies

ObjectiveThis study analyzed the risk factors in patients who developed distal junctional kyphosis (DJK) after posterior cervical fusion.MethodsWe retrospectively analyzed the clinical and radiographic outcomes of 64 patients, aged ≥18 years (51 and 13 male and female patients, respectively), who underwent single-staged multilevel (3–6 levels) posterior cervical fusion surgery due to multiple cervical spondylotic myelopathy. The surgeries were performed by a single spinal surgeon between January 2012 and December 2017. Demographic data, clinical outcomes, and radiological results were collected. We divided the patients into a DJK group and a non-DJK group according to the presence of DJK and investigated the risk factors by comparing the differences between the two groups.ResultsOf the 64 patients, 13 developed DJK. No significant differences in clinical results were observed between the two groups before and immediately after the surgery. At the final follow-up, a higher visual analog score for neck pain was observed in the DJK group compared to the non-DJK group (p<0.01). The DJK group had a significantly lower T1 slope and a significantly higher C2-7 sagittal vertical axis (SVA) before surgery compared to the non-DJK group (p=0.03 and p<0.01, respectively). Immediately after surgery, the difference between the two groups decreased and no significant difference was observed. However, at the last followup, a significantly higher C2-7 SVA was observed in the DJK group (p<0.01). At the last follow up, there is no discrepancy in T1S-CL. In multiple logistic regression analysis, preoperative higher C2-7 SVA and preoperative lower T1 slope were identified as independent risk factors (p=0.03 and p<0.01, respectively). As a result, it was confirmed that DJK occurred along the process of returning to preoperative values.ConclusionDJK can be considered to be caused by cervical misalignment due to excessive change in the surgical site in patients with low T1 slope and high C2-7 SVA before surgery. This also affects the clinical outcome after surgery. It is recommended to refrain from excessive segmental lordosis changes during multilevel cervical post fusion surgery, especially in patients with a small preoperative T1 slope and a large SVA value.

A prospective multicenter study. To compare the surgical outcomes of anterior and posterior fusion surgeries in patients with K-line (-) cervical ossification of the posterior longitudinal ligament (OPLL). 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. 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. 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. 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.

Objective To investigate the safety and effectiveness of posterior approach laminectomy combined with localized resection of ossified posterior longitudinal ligament and dekyphosis for multilevel ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine. Methods Thirty-one cases of thoracic multilevel OPLL was treated with this new technique between August of 2012 and August of 2016. Twenty-nine among the 31 cases were successfully followed up more than two years. Among these 29 cases, 9 were male and the other 20 were female, with an average age of 48.5±7.1 years. The average segment number of OPLL was 6.5±2.2 (range, 3-11). The average segment number of laminectomy was 7.9±2.5 (range, 4-13). There were 26 cases combined with ossification of the ligamentum flavum (OLF). Posterior approach laminectomy combined with localized resection of OPLL and dekyphosis for multilevel OPLL in the thoracic spine was applied to all cases. Firstly, en-bloc laminectomy was performed to all the segments of OPLL. Then the nearest segment of ossification to the kyphotic apex and the most stenotic level was selected and limitedly resected. Finally, wedge-shaped osteotomy was conducted to decrease the kyphosis. The outcomes including recovery rate of myelopathy and the radiological changes were recorded during the post-operative follow-up. Single group pre and post analysis was conducted by using paired t-test. Results Twenty-seven cases underwent one-level circumferential decompression, and the other two case underwent two-level localized resection of the ossified posterior longitudinal ligament. The average operation time was 245.2±75.1 min (range, 131-423 min). The average blood loss was 1 307.9±1 457.7 ml(range, 300-6 000 ml). The average follow-up time was 40.2±14.9 months (range, 25-69 months). The kyphotic angle of the stenotic segments decreased 11.4°±3.5° averagely after the surgery, from pre-operative 28.7°±9.6° to post-operative 17.3°±8.6°. The decreased kyphotic angle was 7.4°±3.1° at the final follow-up with an average kyphotic angel of 22.3°±10.3°. The average length of the resected ossified posterior longitudinal ligament was 11.3±3.9 mm, and the average shortening length of the spinal column was 5.0±3.0 mm (range, 0.4-13.8 mm). The pre-operative Japanese Orthopedic Association (JOA) score was 4.3±2.2 averagely (range, 1-9), and the final JOA score increased to 9.3±2.3 (rang, 3-11). The average recover rate was 85.7% (range, -100% to 100%), and the rate of excellent or good was 89.7%. Among the 29 cases, 6 cases occurred post-operative transient deterioration and regained a satisfactory recovery eventually; one case occurred post-operative paraplegia and never recovered; 19 cases occurred post-operative cerebrospinal fluid leakage and healed under conservative treatment. Conclusion For the thoracic multilevel OPLL, one-stage posterior approach laminectomy combined with localized resection of the ossified posterior longitudinal ligament and dekyphosis can significantly improve the outcomes of the myelopathy with low rate of post-operative paraplegia. Therefore, this new surgery technique is a safe and effective treatment for multilevel OPLL in thoracic spine. Key words: Thoracic vertebrae; Ossification of posterior longitudinal ligament; Spinal stenosis; Decompression, surgical

It is unclear whether anterior cervical decompression and fusion (ADF) or laminoplasty (LMP) results in better outcomes for patients with K-line-positive (+) cervical ossification of the posterior longitudinal ligament (OPLL). The purpose of the study is to compare surgical outcomes and complications of ADF versus LMP in patients with K-line (+) OPLL. The study included 478 patients enrolled in the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament and who underwent surgical treatment for cervical OPLL. The patients who underwent anterior-posterior combined surgery or posterior decompression with instrumented fusion were excluded. The patients with a follow-up period of fewer than 2 years were also excluded, leaving 198 patients with K-line (+) OPLL. Propensity score matching was performed on 198 patients with K-line (+) OPLL who underwent ADF (44 patients) or LMP (154 patients), resulting in 39 pairs of patients based on the following predictors for surgical outcomes: age, preoperative Japanese Orthopaedic Association (JOA) score, C2-7 angle, and the occupying ratio of OPLL. Clinical outcomes were assessed 1 and 2 years after surgery using the recovery rate of the JOA score. Complications and reoperation rates were also investigated. The mean recovery rate of the JOA score 1 year after surgery was 55.3% for patients who underwent ADF and 42.3% (p = 0.06) for patients who underwent LMP. Two years after surgery, the recovery rate was 53.4% for those who underwent ADF and 38.7% for LMP (p = 0.07). Although both surgical procedures yielded good results, the mean recovery rate of JOA scores tended to be higher in the ADF group. The incidence of surgical complications, however, was higher following ADF (33%) than LMP (15%; p = 0.06). The reoperation rate was also higher in the ADF group (15%) than in the LMP group (0%; p = 0.01). Clinical outcomes were good for both ADF and LMP, indicating that ADF and LMP are appropriate procedures for patients with K-line (+) OPLL. Clinical outcomes of ADF 1 and 2 years after surgery tended to be better than LMP, but the analysis did not detect any significant difference in clinical outcomes between the groups. Conversely, patients who underwent ADF had a higher incidence of surgery-related complications. When considering indications for ADF or LMP, benefits and risks of the surgical procedures should be carefully weighed.

Introduction Degenerative cervical myelopathy (DCM) is an umbrella term that includes cervical spondylotic myelopathy, ossification of the posterior longitudinal ligament (OPLL) and other forms of degenerative changes to the spinal axis. The surgical management of OPLL can be technically challenging for spine surgeons and may result in a higher incidence of perioperative complications than surgery for other forms of DCM. It is unclear whether surgery is equally effective and safe in patients with OPLL as it is in other forms of DCM. This study aims to compare the impact of cervical decompressive surgery on functional status and Quality of Life (QOL) outcomes in patients with OPLL and those with other forms of DCM. Material and Methods 479 surgical patients with symptomatic DCM were prospectively enrolled in the CSM-International study at global 16 sites. Patients’ functional and neurological status were evaluated using the modified Japanese Orthopedic Assessment scale (mJOA) and the Nurick score. QOL was assessed using patient-reported outcome measures, including the Neck Disability Index (NDI) and the Short- Form 36 (SF-36) Health Survey. Improvements in functional status and QOL were assessed between baseline and 1- and 2-year follow-ups, and relative gains were compared between patients with and without OPLL. A sub-analysis was conducted in patients with “severe” myelopathy (a preoperative mJOA &lt; 12) to determine whether surgical outcomes differed between patients with severe OPLL and those with other forms of severe DCM. Improvements in preoperative functional status and QOL at 2-years follow-up were compared between the two diagnosis groups, while controlling for relevant confounding variables. Results Of 479 patients, 135 (28.2%) exhibited evidence of OPLL and 344 (71.8%) displayed other forms of degenerative changes. There were no significant differences in demographics, surgical approach, or baseline severity scores between patients with OPLL and those with other forms of DCM. Patients with OPLL achieved similar functional outcomes at 1- and 2-years following surgery when compared with patients with other forms of DCM. With respect to QOL, the NDI and most subscales of the SF-36, there were no differences between the two diagnosis groups. However, the SF-36 Role Limitation Physical subscale ( p = 0.0091) at 1-year and the SF-36 Social Functioning subscale at 1- and 2-years ( p = 0.014, p = 0.018) were significantly lower in OPLL patients. In patients with severe myelopathy (preoperative mJOA &lt; 12), 49 (28.65%) presented with OPLL and 122 (71.35%) with other forms of DCM. There were comparable improvements between preoperative and 2-year postoperative scores across all outcome measures (mJOA, Nurick, NDI, and SF-36) in patients with severe myelopathy due to OPLL and other forms of DCM. Finally, there was a significantly higher rate of perioperative complications in the OPLL group ( p = 0.054). This significant difference was mainly due to a higher incidence of superficial infection ( p = 0.0067), new neck pain ( p = 0.079) and dural tear ( p = 0.076) in the OPLL group. However, rates of neurological complication did not significantly differ ( p = 0.73). Conclusion Surgical decompression for the treatment of OPLL results in significant improvements in functional status and QOL, comparable to gains seen in other forms of DCM.

Ossification of the posterior longitudinal ligament and ossification of the yellow ligament are the main causes of spinal canal stenosis. This article describes a case of ossification of the posterior longitudinal and yellow ligaments on the lumbar spine. The patient presented with gradually worsening left lower-extremity ache and pain. The deep tendon reflex was hyperreflexia in the lower extremities. Disturbances existed in the blade and bowel. The ossified lesion of ossification of the posterior longitudinal ligament was observed at L5-S1, and plain lateral radiographs and computed tomography revealed ossification of the yellow ligament on L3, which occupied a large part of the spinal canal. Because of the findings on the preoperative radiographs, we performed posterior approach decompression and bone grafting and excisied the ossified lesion. Pedicle screws were inserted from L3 to S1. The patient's symptoms disappeared postoperatively, and his Japanese Orthopaedic Association score was 25 two weeks postoperatively. No standard surgical procedure exists for the treatment of lumbar ossification of the posterior longitudinal ligament, but it is important to select a surgical procedure according to individual patient conditions. Many factors, such as local mechanic stress, tissue metabolism, high glucose, and genetics, contribute to the progression of ossification of the posterior longitudinal and yellow ligaments on the lumbar spine. However, the mechanism is unclear. Further study and long-term follow-up on lumbar ossification of the posterior longitudinal ligament is needed.