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.

Pelvic incidence is a risk factor for lower instrumented vertebra failure in adult spinal deformity patients who underwent corrective fusion terminating at the L5 vertebra.

BACKGROUND: Factors related to postoperative mechanical failure after long fusion with lower instrumented vertebra (LIV) at L5 have not been well investigated. Elucidating such factors may allow us to perform alternatives to spinopelvic fusion for adult spinal deformity (ASD) cases. We investigated the incidence and risk factors of LIV failure in patients with ASD who underwent surgical treatment of long corrective fusion until the L5 vertebrae. METHODS: Between 2009 and 2018, 52 patients who underwent corrective fusions to L5 were followed-up for at least one-year. We evaluated the associated patient factors for LIV failure which include loosening of the pedicle screw of LIV, fracture of LIV, distal junctional kyphosis (DJK). RESULTS: The mean age of the participants was 71.2 ± 7.59 (range, 44-84). LIV failure occurred in 20 patients (38.5%), and 6 patients (11.5%) underwent secondary surgery for caudal segments. The mean pelvic incidence (PI) was 52.5 ± 9.8 in the failure group versus 45.3 ± 11.4 in non-failure group (P = 0.02) and pelvic tilt (PT) was 39.1 ± 9.0 versus 32.4 ± 13.0. There were no significant differences in sex, age, body mass index, number of levels fused, and other radiographic data. Logistic regression analysis that included T1 pelvic angle, PT, PI - postoperative LL and PI also identified PI as the only significant determinant of LIV failure (OR = 1.07, P = 0.034). Receiver operating characteristic analysis demonstrated that a PI over 50.0° was associated with LIV failure (sensitivity 63%, specificity 70%, AUC 0.694). CONCLUSION: LIV failure was frequently observed after long corrective fusion for patients with ASD. High PI was found to be a significant risk factor for the LIV failure.

The characteristics of the young patients with cervical ossification of the posterior longitudinal ligament of the spine: A multicenter cross-sectional study.

BACKGROUND: Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by heterotopic bone formation in the posterior longitudinal ligament of the spine. Although the patients with OPLL are more common in the 60s and 70s, we know that there are markedly young patients (e.g., early 40s). However, to the best of our knowledge, there is few reports characterize young patients with cervical OPLL in terms of the imaging features, subjective symptoms, and ADL problems. METHODS: This is the multicenter cross-sectional study. Two hundred and thirty-seven Japanese symptomatic patients with cervical OPLL confirmed by standard X-rays collected from 16 institutions belonging to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament formed by the Japanese Ministry of Health, Labor and Welfare were recruited. Whole spine CT data as well as demographic data such as age, gender, patients-based evaluations, and the 36-item Short Form Health Survey (SF-36) were evaluated. RESULTS: Young group (≦ 45 years old) consisted of 23 patients (8 females and 15 males), accounting for 9.7% of the total. Their characteristics were high body mass index (BMI), significant involvement of trauma in the onset and deterioration of symptoms, and the predominance of thoracic OPLL. The patient-based evaluations did not show a significant difference between the young and non-young groups, or between the genders in the young group except for bodily pain (BP) of SF-36. Female patients in young group had significantly lower BP score of SF-36 than that of male in young group. CONCLUSIONS: Characteristics of young patients with cervical OPLL were high BMI, significant involvement of trauma in the onset and deterioration of symptoms, lower BP score of SF-36 in female, and the predominance of thoracic OPLL.

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.

Prognostic factors for neurological outcome after anterior decompression and fusion for proximal-type cervical spondylotic amyotrophy - A retrospective analysis of 77 cases.

BACKGROUND: Decompression through an anterior approach is theoretically effective for the surgical treatment of cervical spondylotic amyotrophy (CSA), because the pathology usually locates at the anterior side. However, most previous studies investigated posterior surgery or a mix of anterior surgery and posterior surgery in their investigation. Only a few small case series have investigated the surgical outcomes of anterior decompression and fusion (ADF). Therefore, we conducted a multicenter retrospective study that included patients who underwent ADF for proximal-type CSA. METHODS: We analyzed the outcomes of 77 consecutive spinal surgeries performed on proximal-type CSA patients who underwent ADF. Preoperative and postoperative manual muscle tests (MMT) and the patients' backgrounds, radiological findings, and complications were reviewed. We divided the cases into two groups, good-outcome group (MMT improvement â‰§ 2 or improved to MMT 5) and poor-outcome group (others) and evaluated the prognostic factors for outcomes. RESULTS: Of the 77 patients, 48 (62%) showed good neurological outcome. Multiple compressive lesions at anterior horn (AH) and/or ventral nerve roots (VNRs) were detected in 66 patients (85.7%) on the magnetic resonance images. The patients with a single compressive lesion at VNR or AH tended to show good neurological recovery when compare to those with multiple lesions. Age and duration of symptoms were related to the poor outcome in univariate analysis. Duration of symptoms was an independent factor associated with postoperative neurological outcome. The cut-off value for poor outcome was 7.0 months for the symptom duration (sensitivity: 79%, specificity: 54%, area under the curve: 0.69). CONCLUSIONS: Patients with proximal-CSA were more likely to have multiple compressive lesions at an AH and/or a VNR. The prognostic factor for poor neurological outcome was duration of symptoms of ≥7 months.

Effect of bisphosphonates or teriparatide on mechanical complications after posterior instrumented fusion for osteoporotic vertebral fracture: a multi-center retrospective study.

BACKGROUND: The optimal treatment of osteoporosis after reconstruction surgery for osteoporotic vertebral fractures (OVF) remains unclear. In this multicentre retrospective study, we investigated the effects of typically used agents for osteoporosis, namely, bisphosphonates (BP) and teriparatide (TP), on surgical results in patients with osteoporotic vertebral fractures. METHODS: Retrospectively registered data were collected from 27 universities and affiliated hospitals in Japan. We compared the effects of BP vs TP on postoperative mechanical complication rates, implant-related reoperation rates, and clinical outcomes in patients who underwent posterior instrumented fusion for OVF. Data were analysed according to whether the osteoporosis was primary or glucocorticoid-induced. RESULTS: A total of 159 patients who underwent posterior instrumented fusion for OVF were included. The overall mechanical complication rate was significantly lower in the TP group than in the BP group (BP vs TP: 73.1% vs 58.2%, p = 0.045). The screw backout rate was significantly lower and the rates of new vertebral fractures and pseudoarthrosis tended to be lower in the TP group than in the BP group. However, there were no significant differences in lumbar functional scores and visual analogue scale pain scores or in implant-related reoperation rates between the two groups. The incidence of pseudoarthrosis was significantly higher in patients with glucocorticoid-induced osteoporosis (GIOP) than in those with primary osteoporosis; however, the pseudoarthrosis rate was reduced by using TP. The use of TP also tended to reduce the overall mechanical complication rate in both primary osteoporosis and GIOP. CONCLUSIONS: The overall mechanical complication rate was lower in patients who received TP than in those who received a BP postoperatively, regardless of type of osteoporosis. The incidence of pseudoarthrosis was significantly higher in patients with GIOP, but the use of TP reduced the rate of pseudoarthrosis in GIOP patients. The use of TP was effective to reduce postoperative complications for OVF patients treated with posterior fusion.

Short- versus long-segment posterior spinal fusion with vertebroplasty for osteoporotic vertebral collapse with neurological impairment in thoracolumbar spine: a multicenter study.

BACKGROUND: Vertebroplasty with posterior spinal fusion (VP + PSF) is one of the most widely accepted surgical techniques for treating osteoporotic vertebral collapse (OVC). Nevertheless, the effect of the extent of fusion on surgical outcomes remains to be established. This study aimed to evaluate the surgical outcomes of short- versus long-segment VP + PSF for OVC with neurological impairment in thoracolumbar spine. METHODS: We retrospectively collected data from 133 patients (median age, 77 years; 42 men and 91 women) from 27 university hospitals and their affiliated hospitals. We divided patients into two groups: a short-segment fusion group (S group) with 2- or 3-segment fusion (87 patients) and a long-segment fusion group (L group) with 4- through 6-segment fusion (46 patients). Surgical invasion, clinical outcomes, local kyphosis angle (LKA), and complications were evaluated. RESULTS: No significant differences between the two groups were observed in terms of neurological recovery, pain scale scores, and complications. Surgical time was shorter and blood loss was less in the S group, whereas LKA at the final follow-up and correction loss were superior in the L group. CONCLUSION: Although less invasiveness and validity of pain and neurological relief are secured by short-segment VP + PSF, surgeons should be cautious regarding correction loss.

The characteristics of the patients with radiologically severe cervical ossification of the posterior longitudinal ligament of the spine: A CT-based multicenter cross-sectional study.

BACKGROUND: Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by heterotopic bone formation in the posterior longitudinal ligament of the spine. We know that the size and distribution of the ossified lesions in patients with OPLL are different in each case. However, the characteristics of the patients with radiologically severe cervical OPLL remain unknown. METHODS: The participants of our study were symptomatic patients with cervical OPLL who were diagnosed by standard radiographs of the cervical spine. Whole-spine CT data and demographic data such as age and sex were obtained from 20 institutions belonging to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament. According to the number of the levels involved by OPLL, we stratified the patients into two subgroups: severe group (S-group) and non-severe group (NS-group) to delineate the characteristics of radiologically severe patients with cervical OPLL. We also evaluated the most compressed level and the degree of occupying ratio of cervical spinal canal by OPLL at the most compressed level. RESULTS: A total of 234 patients with a mean age of 65 years were recruited. The S-group consisted of 48 patients (21%, 12 females and 36 males) and the NS-group consisted of 92 patients (79%, 22 females and 70 males). The mean age of males in the S-group (68 years old) was significantly higher than that of males in the NS-group (64 years old); however there was no significant difference in the mean age in females between the S-group (69 years old) and the NS-group (66 years old). No significant difference of body mass index, ossification of the nuchal ligament-positivity and presence of diabetes mellitus were found between the S- and the NS-group. CONCLUSIONS: It is likely that the manner of extension of cervical OPLL is different between male and female patients.

Surgical outcomes for distal-type cervical spondylotic amyotrophy: a multicenter retrospective analysis of 43 cases.

PURPOSE: Distal-type cervical spondylotic amyotrophy (CSA) is a rare form of cervical spondylosis that causes muscle weakness of upper extremities. The pathophysiology and appropriate surgical method for the treatment of CSA are still controversial. We investigated clinical outcomes in surgically treated distal-type CSA. METHODS: The authors executed an analysis of the outcomes of 43 consecutive spinal surgeries performed in distal-type CSA patients. The duration of symptoms, perioperative manual muscle test (MMT) results, radiological findings, and perioperative complications were reviewed. We compared surgical outcomes between different approaches and examined the factors related to poor outcomes (MMT improvement ≤ 0) after surgery. RESULTS: The pathophysiology of CSA was mostly caused by a combination of multiple lesions in the anterior horn and/or nerve root. Nineteen of 29 patients (65.5%) who received anterior approach methods were included in the good outcome group (MMT improvement ≥ 1), whereas 7 of 14 patients (50.0%) in the posterior group were classified as good. In the anterior group, the mean MMT grade significantly improved from 2.6 to 3.4 (p = 0.0035) despite the higher rate of complications. The duration of symptoms was substantially associated with poor outcomes. The MMT grade significantly improved from 2.2 to 3.2 (p = 0.0118) in the < 6 months group. Cervical alignments and preoperative MMT grade were not statistically associated with poor outcomes. CONCLUSIONS: Patients with poor outcomes had symptoms for a longer duration. We found tolerable clinical outcomes within 6 months from onset. The anterior approaches might be recommended because this procedure significantly improved MMT levels in the hands. These slides can be retrieved under Electronic Supplementary Material.

Surgical outcomes of spinal fusion for osteoporotic thoracolumbar vertebral fractures in patients with Parkinson's disease: what is the impact of Parkinson's disease on surgical outcome?

BACKGROUND: To date, there have been little published data on surgical outcomes for patients with PD with thoracolumbar OVF. We conducted a retrospective multicenter study of registry data to investigate the outcomes of fusion surgery for patients with Parkinson's disease (PD) with osteoporotic vertebral fracture (OVF) in the thoracolumbar junction. METHODS: Retrospectively registered data were collected from 27 universities and their affiliated hospitals in Japan. In total, 26 patients with PD (mean age, 76 years; 3 men and 23 women) with thoracolumbar OVF who underwent spinal fusion with a minimum of 2 years of follow-up were included (PD group). Surgical invasion, perioperative complications, radiographic sagittal alignment, mechanical failure (MF) related to instrumentation, and clinical outcomes were evaluated. A control group of 296 non-PD patients (non-PD group) matched for age, sex, distribution of surgical procedures, number of fused segments, and follow-up period were used for comparison. RESULTS: The PD group showed higher rates of perioperative complications (p < 0.01) and frequency of delirium than the non-PD group (p < 0.01). There were no significant differences in the degree of kyphosis correction, frequency of MF, visual analog scale of the symptoms, and improvement according to the Japanese Orthopaedic Association scoring system between the two groups. However, the PD group showed a higher proportion of non-ambulators and dependent ambulators with walkers at the final follow-up (p < 0.01). CONCLUSIONS: A similar surgical strategy can be applicable to patients with PD with OVF in the thoracolumbar junction. However, physicians should pay extra attention to intensive perioperative care to prevent various adverse events and implement a rehabilitation regimen to regain walking ability.

Surgical outcomes of spinal fusion for osteoporotic vertebral fracture in the thoracolumbar spine: Comprehensive evaluations of 5 typical surgical fusion techniques.

BACKGROUND: A consensus on the optimal surgical procedure for thoracolumbar OVF has yet to be reached due to the previous relatively small number of case series. The study was conducted to investigate surgical outcomes for osteoporotic vertebral fracture (OVF) in the thoracolumbar spine. METHODS: In total, 315 OVF patients (mean age, 74 years; 68 men and 247 women) with neurological symptoms who underwent spinal fusion with a minimum 2-year follow-up were included. The patients were divided into 5 groups by procedure: anterior spinal fusion alone (ASF group, n = 19), anterior/posterior combined fusion (APSF group, n = 27), posterior spinal fusion alone (PSF group, n = 40), PSF with 3-column osteotomy (3CO group, n = 92), and PSF with vertebroplasty (VP + PSF group, n = 137). RESULTS: Mean operation time was longer in the APSF group (p < 0.05), and intraoperative blood loss was lower in the VP + PSF group (p < 0.05). The amount of local kyphosis correction was greater in the APSF and 3CO groups (p < 0.05). Clinical outcomes were approximately equivalent among all groups. CONCLUSION: All 5 procedures resulted in acceptable neurological outcomes and functional improvement in walking ability. Moreover, they were similar with regard to complication rates, prevalence of mechanical failure related to the instrumentation, and subsequent vertebral fracture. Individual surgical techniques can be adapted to suit patient condition or severity of OVF.

Complications after spinal fixation surgery for osteoporotic vertebral collapse with neurological deficits: Japan Association of Spine Surgeons with ambition multicenter study.

BACKGROUND: There have been few reports on the incidence and risk factors of the complications after spinal fixation surgery for osteoporotic vertebral collapse (OVC) with neurological deficits. This study aimed to identify the incidence and risk factors of the complications after OVC surgery. METHODS: In this retrospective multicenter study, a total of 403 patients (314 women and 89 men; mean age 73.8 years) who underwent spinal fixation surgery for OVC with neurological deficits between 2005 and 2014 were enrolled. Data on patient demographics were collected, including age, sex, body mass index, smoking, steroid use, medical comorbidities, and surgical procedures. All postoperative complications that occurred within 6 weeks were recorded. Patients were classified into two groups, namely, complication group and no complication group, and risk factors for postoperative complications were investigated by univariate and multivariate analyses. RESULTS: Postoperative complications occurred in 57 patients (14.1%), and the most common complication was delirium (5.7%). In the univariate analysis, the complication group was found to be older (p = 0.039) and predominantly male (p = 0.049), with higher occurrence rate of liver disease (p = 0.001) and Parkinson's disease (p = 0.039) compared with the no-complication group. In the multivariate analysis, the significant independent risk factors were age (p = 0.021; odds ratio [OR] 1.051, 95% confidence interval [CI] 1.007-1.097), liver disease (p < 0.001; OR 8.993, 95% CI 2.882-28.065), and Parkinson's disease (p = 0.009; OR 3.636, 95% CI 1.378-9.599). CONCLUSIONS: Complications after spinal fixation surgery for OVC with neurological deficits occurred in 14.1%. Age, liver disease, and Parkinson's disease were demonstrated to be independent risk factors for postoperative complications.

Distribution of ossified spinal lesions in patients with severe ossification of the posterior longitudinal ligament and prediction of ossification at each segment based on the cervical OP index classification: a multicenter study (JOSL CT study).

BACKGROUND: In patients with ossification of the posterior longitudinal ligament (OPLL) in the cervical spine, it is well known that the thoracic ossified lesions often coexist with the cervical lesions and can cause severe myelopathy. However, the prevalence of OPLL at each level of the thoracic and lumbar spinal segments is unknown. The aims of this study were to investigate how often OPLL occurs at each level in the thoracolumbar spine in patients with a radiological diagnosis of cervical OPLL and to identify the spinal levels most likely to develop ossification. METHODS: Data were collected from 20 institutions in Japan. Three hundred and twenty-two patients with a diagnosis of cervical OPLL were included. The OPLL index (OP index), defined as the sum of the vertebral body and intervertebral disc levels where OPLL is present, was used to determine disease severity. An OP index ≥20 was defined as severe OPLL. The prevalence of OPLL at each level of the thoracic and lumbar spinal segments was calculated. RESULTS: Women were more likely to have ossified lesions in the thoracolumbar spine than men. Severe OPLL was significantly more common in women than in men (20% vs. 4.5%). For thoracic vertebral OPLL, the most frequently affected was the T1 segment in both men and women, followed by the T1/2 and T3/4 intervertebral levels in men and women, respectively. Ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men with severe OPLL, whereas OPLL was more diffusely distributed in the thoracic spine in women with severe OPLL. CONCLUSION: Thoracolumbar OPLL occurred most often at T1 in men and at T3/4 in women. In severe OPLL cases, although ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men, OPLL could be observed more diffusely in the thoracic spine in women.

A multi-train electrical stimulation protocol facilitates transcranial electrical motor evoked potentials and increases induction rate and reproducibility even in patients with preoperative neurological deficits.

This study sought to evaluate the facilitation effect of repetitive multi-train transcranial electrical stimulation (mt-TES) at 2 repetition rates on transcranial electrical motor evoked potential (Tc-MEP) monitoring during spinal surgery, and to assess the induction rate in patients with impaired motor function from a compromised spinal cord or spinal nerve. We studied 32 consecutive patients with impaired motor function undergoing cervical or thoracic spinal surgery (470 muscles). A series of 10 TESs with 5 pulse trains were preoperatively delivered at 2 repetition rates (1 and 5 Hz). All peak-topeak amplitudes of the MEPs of the upper and lower extremity muscles elicited by the 10 TESs were measured. The induction rates of the lower extremity muscles were also assessed with muscle and preoperative lower extremity motor function scores. In each of the muscles, MEP amplitudes were augmented by about 2-3 times at 1 Hz and 5-6 times at 5 Hz. Under the 5-Hz condition, all limb muscles showed significant amplification. Also, in all preoperative motor function score groups, the amplitudes and induction rates of the lower extremity muscles were significantly increased. Moreover, the facilitation effects tended to peak in the last half of the series of 10 TESs. In all score groups of patients with preoperative neurological deficits, repetitive mt-TES delivered at a frequency of 5 Hz markedly facilitated the MEPs of all limb muscles and increased the induction rate. We recommend this method to improve the reliability of intraoperative monitoring during spinal surgery.

Identifying Factors for Predicting Postoperative Segmental Motor Paralysis in Patients Undergoing Anterior Cervical Spine Surgery: A Multicenter Study.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To investigate the incidence of and risk factors for segmental motor paralysis after anterior cervical spine surgery. SUMMARY OF BACKGROUND DATA: Segmental motor paralysis is a potential complication following both anterior and posterior cervical decompression procedures; however, previous studies investigating risk factors for segmental motor paralysis after anterior cervical spine surgery were limited by small sample sizes. Consequently, the exact pathogenesis and risk factors for this complication remain poorly understood, highlighting the need for larger-scale investigations focused exclusively on anterior cervical spine surgeries. METHODS: We retrospectively reviewed the clinico-demographic and operative factors and postoperative outcomes of 1,428 patients undergoing anterior cervical spine surgery at three spine centers in Japan. Postoperative segmental motor paralysis was defined as deterioration of upper extremity muscle strength by ≥1 grade; recovery was defined as a return to preoperative muscle strength levels. Univariate and multivariate analyses were performed to identify risk factors. RESULTS: Ninety-nine patients (6.9%) developed segmental motor paralysis, mostly involving the C5 segment (81.8%), the incidence being highest in patients with ossification of the posterior longitudinal ligament (OPLL) and those undergoing anterior cervical corpectomy and fusion or hybrid fusion (discectomy + corpectomy). Older age, male sex, higher body mass index, OPLL, and cervical corpectomy were independent risk factors for paralysis, with these patients having significantly worse clinical outcomes at 1 year postoperatively. Most patients (74/99, 79.6%) regained preoperative muscle strength levels an final follow up. CONCLUSION: This study identified important clinico-demographic and operative risk factors for segmental motor paralysis after anterior cervical spine surgery. Patients undergoing corpectomy, with or without OPLL, were found to be at particularly high risk. While most patients recover well, worse outcomes with segmental motor paralysis highlight the importance of preventing this complication, particularly for OPLL patients and corpectomy procedures. LEVEL OF EVIDENCE: III.

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.

Clinical Characteristics of Patients with Ossification of the Posterior Longitudinal Ligament and a High OP Index: A Multicenter Cross-Sectional Study (JOSL Study).

BACKGROUND: The purpose of this study was to clarify the clinical features of ossification of the posterior longitudinal ligament (OPLL) and extreme ossification at multiple sites. METHODS: This prospective study involved patients with a diagnosis of cervical OPLL at 16 institutions in Japan. Patient-reported outcome measures, including responses on the Japanese Orthopaedic Association (JOA) Cervical Myelopathy Evaluation Questionnaire (JOA-CMEQ), JOA Back Pain Evaluation Questionnaire (JOA-BPEQ), and visual analog scale pain score, were collected to investigate clinical status. In each patient, the sum of the levels at which OPLL was located (OP index) was evaluated on whole-spine computed tomography, along with ossification of other spinal ligaments including the anterior longitudinal ligament (OALL), ligament flavum (OLF), supra- and intraspinous ligaments (SSL), and diffuse idiopathic skeletal hyperostosis (DISH). The distribution of OP index values in the study population was investigated, and the clinical and radiologic characteristics of patients in the top 10% were assessed. RESULTS: In total, 236 patients (163 male, 73 female; mean age 63.5 years) were enrolled. Twenty-five patients with OP index ≥ 17 were categorized into a high OP index group and the remainder into a moderate/low OP index group. There were significantly more women in the high OP index group. Patients in the high OP index group also had significantly poorer scores for lower extremity function and quality of life on the JOA-CMEQ and in each domain but not for body pain on the JOA-BPEQ compared with those in the moderate/low OP index group. Patients in the high OP index group had more OALL in the cervical spine and more OLF and SSL in the thoracic spine. The prevalence of DISH was also significantly higher in the high OP index group. In the high OP index group, interestingly, OPLL was likely to be present adjacent to DISH in the cervicothoracic and thoracolumbar spine, especially in men, and often coexisted with DISH in the thoracic spine in women. CONCLUSION: This prospective cohort registry study is the first to demonstrate the clinical and radiologic features of patients with OPLL and a high OP index. In this study, patients with a high OP index had poorer physical function in the lumbar spine and lower extremities and were also predisposed to extreme ossification of spinal ligaments other than the OPLL.

Effect of low body mass index on clinical recovery after fusion surgery for osteoporotic vertebral fracture: A retrospective, multicenter study of 237 cases.

A retrospective multicenter study. Body mass index (BMI) is recognized as an important determinant of osteoporosis and spinal postoperative outcomes; however, the specific impact of BMI on surgery for osteoporotic vertebral fractures (OVFs) remains inconclusive. This retrospective multicenter study investigated the impact of BMI on clinical outcomes following fusion surgery for OVFs. 237 OVF patients (mean age, 74.3 years; 48 men and 189 women) with neurological symptoms who underwent spinal fusion were included in this study. Patients were grouped by World Health Organization BMI categories: low BMI (<18.5 kg/m2), normal BMI (≥18.5 and <25 kg/m2), and high BMI (≥25 kg/m2). Patients' backgrounds, surgical method, radiological findings, pain measurements, activities of daily living (ADL), and postoperative complications were compared after a mean follow-up period of 4 years. As results, the proportion of patients able to walk independently was significantly smaller in the low BMI group (75.0%) compared with the normal BMI group (89.9%; P = .01) and the high BMI group (94.3%; P = .04). Improvement in the visual analogue scale for leg pain was significantly less in the low BMI group than the high BMI group (26.7 vs 42.8 mm; P = .046). Radiological evaluation, the Frankel classification, and postoperative complications were not significantly different among all 3 groups. Improvement of pain intensity and ADL in the high BMI group was equivalent or non-significantly better for some outcome measures compared with the normal BMI group. Leg pain and independent walking ability after fusion surgery for patients with OVFs improved less in the low versus the high BMI group. Surgeons may want to carefully evaluate at risk low BMI patients before fusion surgery for OVF because poor clinical results may occur.

Lumbar radiculopathy due to foraminal stenosis with ossification of the ligamentum flavum: a case report.

The patient was an 82-year-old woman with a diagnosis of lumbar radiculopathy due to foraminal stenosis accompanied by ossification of the ligamentum flavum (OLF). Computed tomography scans of the lumbar spine revealed ossification in the capsular portion of the ligamentum flavum around the L2-L3 facet joint. In addition, computed tomography images acquired a few months before the onset of radiculopathy had shown that the ossification site had gradually expanded to include the superior articular process. The patient's symptoms disappeared immediately after excision of the OLF. Histopathological examination of the resected specimen indicated replacement of degenerated ligamentum flavum with ossified tissue via a gradual endochondral ossification process. It is important to be aware that foraminal stenosis can in rare cases occur due to OLF, even in the lumbar spine.

Anterior Cervical Corpectomy with Fusion versus Anterior Hybrid Fusion Surgery for Patients with Severe Ossification of the Posterior Longitudinal Ligament Involving Three or More Levels: A Retrospective Comparative Study.

Various studies have found a high incidence of early graft dislodgement after multilevel corpectomy. Although a hybrid fusion technique was developed to resolve implant failure, the hybrid and conventional techniques have not been clearly compared in terms of perioperative complications in patients with severe ossification of the posterior longitudinal ligament (OPLL) involving three or more levels. The purpose of this study was to compare clinical and radiologic outcomes between anterior cervical corpectomy with fusion (ACCF) and anterior hybrid fusion for the treatment of multilevel cervical OPLL. We therefore retrospectively reviewed the clinical and radiologic data of 53 consecutive patients who underwent anterior fusion to treat cervical OPLL: 30 underwent ACCF and 23 underwent anterior hybrid fusion. All patients completed 2 years of follow-ups. Implant migration was defined as subsidence > 3 mm. There were no significant differences in demographics or clinical characteristics between the ACCF and hybrid groups. Early implant failure occurred significantly more frequently in the ACCF group (5 cases, 16.7%) compared with the hybrid group (0 cases, 0%). The fusion rate was 80% in the ACCF group and 100% in the hybrid group. Although both procedures can achieve satisfactory neurologic outcomes for multilevel OPLL patients, hybrid fusion likely provides better biomechanical stability than the conventional ACCF technique.