Japanese Orthopaedic Association Recovery Research Articles

Mid-Term Results of Single-Level Posterior Lumbar Interbody Fusion in Patients with Pelvic Incidence Minus Lumbar Lordosis Mismatch

BackgroundRecent literature suggests that sagittal imbalance is a risk factor for adjacent segment disease (ASD) following fusion surgery. This study explored the influence of pelvic incidence minus lumbar lordosis (PI-LL) mismatch on the mid-term results and reoperation rate after single-level posterior lumbar interbody fusion (PLIF). MethodsThe participants of this study included 253 patients (80 men and 173 women; mean age 68.2 years) who underwent L4-5 single-segment PLIF. Preoperative PI-LL mismatch was defined as a PI-LL of 30° or greater. The patients were divided into two groups according to the presence or absence of PI-LL mismatch (PI-LL mismatch group; group M, Control group; group C), and the clinical outcomes and radiographic parameters were compared. ResultsOf the 253 cases, 25 were classified in group M and 228 in group C. The Japanese Orthopaedic Association (JOA) score at five years postoperatively was 23.0±3.6 in group M and 23.5±5.1 in group C, and the recovery rate was 66.2±32.6% in group M and 64.6±21.4% in group C and there was no significant difference in the recovery rate between the two groups. All radiographic parameters except SS were significantly worse in group M. One patient (4.3%) in Group M and 18 patients (7.8%) in Group C required revision surgery at 2.4 years (range 0.0–5.0) and there was no significant difference in the revision rate between the two groups. ConclusionsThe mid-term results of L4-5 single-level PLIF were compared with and without PI-LL mismatch, with the threshold defined as 30°; however, there were no significant differences in both the JOA recovery and reoperation rates between the two groups.

Preoperative Cervical Range of Motion in Flexion as a Risk Factor for Postoperative Cervical Sagittal Imbalance After Laminoplasty.

Retrospective study. To investigate factors associated with cervical sagittal imbalance (CSI) after cervical laminoplasty (LMP). Preoperative dynamic cervical sagittal alignment is an important predictor for changes in cervical sagittal alignment and clinical outcomes after LMP. However, the impact of preoperative dynamic cervical sagittal alignment on postoperative changes in the cervical sagittal vertical axis (cSVA) after LMP remains unclear. We hypothesized that preoperative cervical flexion and extension function are associated with the changes in cSVA and clinical outcomes and found potential risk factors for post-LMP CSI. Patients undergoing LMP at a single institution between January 2019 and December 2021 were retrospectively reviewed. The average follow-up period was 19 months. The parameters were collected before the surgery and at the final follow-up. We defined the changes in cSVA (△cSVA) ≤ -10 mm as the improvement group, -10 mm < △cSVA ≤ 10 mm as the stable group, and △cSVA > 10 mm as the deterioration group. Multivariate logistic regression was used to evaluate factors associated with postoperative CSI. The χ 2 test was used to compare categorical data between groups. T tests, analysis of variance, Kruskal-Wallis tests, and Mann-Whitney Wilcoxon tests were used to assess the differences between radiographic and clinical parameters among groups. A receiver operating characteristic curve analysis was used to identify optimal cutoff values. The study comprised 102 patients with cervical spondylotic myelopathy. The Japanese Orthopedic Association recovery rate was better in the improvement group and a significant aggravation in neck pain was observed in the deterioration group after surgery. Cervical Flex range of motion (ROM; spine range of flexion) was significantly higher in the deterioration group. The multivariate logistic regression model suggested that greater Flex ROM and starting LMP at C3 were significant risk factors for postoperative deterioration of cervical sagittal balance. Receiver operating characteristic curves showed that the cutoff value for preoperative Flex ROM was 34.10°. Preoperative dynamic cervical sagittal alignment influences postoperative cervical sagittal balance after LMP. Cervical LMP should be carefully considered for patients with a preoperative high Flex ROM, as CSI is likely to occur after surgery. Level 3.

Predictive Effect of Cervical Sagittal Parameters and Corresponding Segmental Paravertebral Muscle Degeneration on the Occurrence of Cervical Kyphosis Following Cervical Laminoplasty

Cervical sagittal parameters and paravertebral muscle degeneration are important factors for the occurrence of cervical spondylotic myelopathy. However, the relationship between the 2 risk factors and cervical kyphosis following cervical laminoplasty remains unknown. A total of 130 patients undergoing cervical laminoplasty were enrolled from July 2018 to July 2020 and were followed up for at least 24months. Clinical recovery was recorded, including the Japanese Orthopedic Association, neck disability index and visual analog scale scores. Radiographic sagittal parameters were measured on cervical lateral radiographs: T1 slope (T1S), C2-C7 Cobb lordotic angle (CLA), C2-C7 sagittal vertical axis, O-C2 angle, and T1S-CLA. The magnetic resonance imaging (MRI) parameters of the paraspinal muscles were also measured, including cross-sectional area and fat infiltration (FI). The patients were divided into a kyphosis group and a lordosis group based on the last follow-up results of CLA. Multivariate logistic analysis was performed to analyze risk factors for kyphosis following laminoplasty. Thirty-two patients were assigned to the kyphosis group and 98 were assigned to the lordosis group. Patient baseline and surgical information in the 2 groups showed no statistically significant difference. In the comparison of clinical recovery, patients with kyphosis showed a lower Japanese Orthopedic Association recovery rate than the lordosis group. For the radiographic parameters and muscle condition comparison, CLA, T1S-CLA, and FI were the most significant parameters. The logistic regression revealed that T1S-CLA and FI were the most important variables that predicted kyphosis. We concluded that FI remarkably differed in the paraspinal muscles in the 2 groups. Multivariate logistic regression demonstrated that T1S-CLA and FI significantly influenced the process of kyphosis after cervical laminoplasty.

Effect of Early Postoperative Resolution of MRI Signal Intensity Changes on the Outcomes of Degenerative Cervical Myelopathy.

A retrospective cohort study. To investigate whether the timing of postoperative resolution of increased signal intensity (ISI) in the spinal cord is associated with surgical outcomes. It remains unclear whether changes in ISI in the early postoperative period influence surgical outcomes. This retrospective cohort study evaluated consecutive patients undergoing surgery for degenerative cervical myelopathy at a single academic hospital between January 2012 and September 2019. These patients underwent magnetic resonance imaging (MRI) preoperatively, within two weeks postoperatively (early MRI) and after six months postoperatively (late MRI). ISI was classified as follows: grade 0, none; grade 1, light (obscure); and grade 2, intense (bright). Patients were categorized into the following three groups: those with postoperative ISI resolution at early MRI (group E) or only at the late MRI (group L) stage and those whose ISI was persistent (group P). The surgical outcomes were compared between these three groups. We included 204 patients with complete data eligible for the analysis, and 163 of them had preoperative ISI. Postoperative ISI regression was observed in 49 (30.1%) patients. Of these 49 patients, 25 showed ISI resolution at early MRI (group E) and 24 only at late MRI (group L). All 49 were grade 1 on preoperative MRI, and this was not found to significantly impact surgical outcomes. In comparing surgical outcomes between the groups, group E had better postoperative Japanese Orthopedic Association scores and Japanese Orthopedic Association recovery rates than groups L and P. No significant differences were observed between groups L and P. Early resolution of preoperative grade 1 ISI on postoperative T2-weighted MRI may be associated with better surgical outcomes in patients with degenerative cervical myelopathy undergoing cervical spinal surgery.

Risk factors for poor neurological outcomes after unilateral open-door laminoplasty: an analysis of the characteristics of ectopic bone

BackgroundThe factors affecting neurological outcomes with unilateral open-door laminoplasty have been controversial. The purpose of this study was to evaluate the impact of the characteristics of ectopic bone on poor neurological outcomes after unilateral open-door laminoplasty.MethodsWe retrospectively analyzed the clinical data of 112 patients who underwent unilateral open-door laminoplasty from September 2017 to September 2020. According to the Japanese Orthopedic Association score recovery rate after surgery (Japanese Orthopedic Association recovery rate ≥ 50% and < 50%, respectively), all patients were divided into “poor” and “good” groups. The characteristics of ectopic bone and the position relationship between the open side and ectopic bone (for lateral ossification) in the two groups were compared and analyzed. Univariate and multivariate analyses were used to determine the risk factors for poor neurological outcome.ResultsWe identified patients with a mean age of 58.39 years and a mean follow-up of 25.43 months. Sixty (53.6%) patients experienced recovery of poor neurological function. On univariable analysis, significant predictors of poor neurological recovery were occupation rate of spinal canal > 60% (p = 0.000), ossification extending to C2 (p = 0.006), lateral ossification (p = 0.032) and opening side on the ipsilateral side of the ectopic bone (p = 0.011). Multivariate logistic regression analysis revealed that the occupation rate of spinal canal > 60% (P = 0.003), ossification extending to C2 (P = 0.041) and opening the door on the ipsilateral side for lateral ossification (P = 0.013) were independent risk factors for poor prognosis of neurological function.ConclusionsAn occupation ratio > 60% is the most important risk factor. Another one is ossification of the posterior longitudinal ligament extending to C2. Meanwhile, opening the door on the ipsilateral side is indeed a risk factor for lateral ossification. Better neurological function may be obtained by choosing the opposite side of the heterotopic bone as the open side. Therefore, the design of the surgical plan should comprehensively consider these factors.

The surgical outcome of multilevel anterior cervical discectomy and fusion in myelopathic elderly and younger patients

The elderly population has an increased risk of degenerative cervical myelopathy due to multilevel disease, causing motor and sensory dysfunctions and a poor quality of life. Multilevel anterior cervical discectomy and fusion (ACDF) is an alternative surgical treatment option, but has a perceived higher risk of complications. The goal of this study is to report the outcome. We retrospectively reviewed patients from 2006 to 2019 undergoing multilevel ACDF for degenerative cervical myelopathy and compared outcomes and complications between elder patients (aged 70 and above) and younger patients (below 70). The patients’ comorbidities, and postoperative complications, radiographic parameters such as C2–C7 Cobb angle, C2–C7 sagittal vertical axis, inter-body height of surgical levels and fusion rate were recorded. Japanese Orthopaedic Association (JOA) score and modified Odom’s score were collected. Included were 18 elderly (mean age 74, range 70–87) and 45 young patients (mean age 56, range 43–65) with a follow-up of 43.8 and 55.5 months respectively. Three-level ACDF was the most common. The ratios of ASA class III patients were 94.4% and 48.9% (p < 0.001). The Charlson comorbidity indexes were 4.3 ± 1.03 and 2.1 ± 1.11 (p < 0.001). The average lengths of hospital stays were 4.9 and 4.6 days. Eleven patients (61.1%) in the elderly group experienced at least one short-term complication, compared with 16 patients (35.6%) in the younger group (p < 0.05). The middle-term complications were comparable (22.2% and 20.0%). The JOA score, recovery rate and modified Odom score showed comparable result between groups. Despite its extensiveness, multilevel ACDF is feasible for the elder patients with good clinical outcome and fusion rate. When compared to younger cohort, there is a trend of lower preoperative JOA score and recovery rate. The short-term complication rate is higher in the elderly group.

Microendoscopic Decompression for Lumbar Spinal Stenosis Associated with Adjacent Segment Disease following Lumbar Fusion Surgery: 5-year Follow-up of a Retrospective Case Series.

Surgical treatment options for lumbar spinal stenosis (LSS) based on adjacent segment disease (ASD) after spinal fusion typically involve decompression, with or without fusion, of the adjacent segment. The clinical benefits of microendoscopic decompression for LSS based on ASD have not yet been fully elucidated. We aimed to investigate the clinical results of microendoscopic spinal decompression surgery for LSS based on ASD. From 2011 to 2014, consecutive patients who underwent microendoscopic spinal decompression without fusion for LSS based on ASD were enrolled. Data of 32 patients (17 men and 15 women, with a mean age of 70.5 years) were reviewed. Japanese Orthopaedic Association score and low back pain/leg pain visual analog scale score were utilized to measure neurologic and axial pain outcomes, respectively. Additionally, after the surgeries, we analyzed the magnetic resonance imaging (MRI), computed tomography (CT) scans, or radiographs to identify any new instabilities of the decompressed segments or progression of ASD adjacent to the decompressed segments. The Japanese Orthopaedic Association recovery rate at the 5-year postoperative visit was 49.2%. The visual analog scale scores for low back pain and leg pain were significantly improved. The minimum clinically important difference for leg pain (decrease by ≥24 mm) and clinically important difference for low back pain (decrease by ≥38 mm) were achieved in 84% (27/32) and 72% (23/32) of cases, respectively. Regarding new instability after microendoscopic decompression, no cases had apparent spinal instability at the decompression segment and adjacent segment to the decompressed segment. Microendoscopic spinal decompression is an effective treatment alternative for patients with LSS caused by ASD. The ability to perform neural decompression while maintaining key stabilizing structures minimizes subsequent clinical instability. The substantial clinical and economic benefits of this approach may make it a favorable alternative to performing concurrent fusion in many patients.

Is Cervical Disc Replacement Valuable in 3-Level Hybrid Surgery Compared with 3-Level Anterior Cervical Discectomy and Fusion?

Cervical degenerative disc disease is common in clinical practice. Surgery is among the most effective treatments for patients with cervical radiculopathy, myelopathy, or stenosis. Which treatment is the best option for multilevel cervical degenerative disc disease is controversial. Hybrid surgery, combined cervical disc replacement and anterior cervical discectomy and fusion, may be an alternative treatment for multilevel cervical degenerative disc disease. Sixty-four patients with 3-level hybrid surgery and 37 patients with 3-level anterior cervical discectomy and fusion were reviewed retrospectively. Clinical outcomes were based on visual analog scale, Neck Disability Index, 36-Item Short Form Survey, and Japanese Orthopaedic Association scores and Japanese Orthopaedic Association recovery rate. Radiologic assessments included range of motion (ROM) of C2-C7 and adjacent level and cervical lordosis of C2-C7. Perioperative parameters, fusion condition, and complications were assessed. There were no statistical differences observed between the 2 groups for Japanese Orthopaedic Association, Neck Disability Index, or visual analog scale scores. The hybrid surgery group had better physical and mental 36-Item Short Form Survey scores than the fusion group at 1-year follow-up (physical component summary: 49.34 vs. 46.70, P= 0.012; mental component summary: 45.67 vs. 43.95, P= 0.004). ROM of C2-C7 and adjacent levels was less compromised in the hybrid group compared with baseline (64.60% vs. 51.34%, P < 0.001). Cervical lordosis was decreased with time in both groups but was acceptable at final follow-up, and both groups showed solid fusion. Normal ROM and solid fusion were achieved at both arthroplasty and arthrodesis levels. ROM of replacement levels in different locations of the 3-level construct was acceptable.

Does Preoperative T1 Slope and Cervical Lordosis Mismatching Affect Surgical Outcomes After Laminoplasty in Patients with Cervical Spondylotic Myelopathy?

To assess whether preoperative T1 slope and cervical lordosis mismatching affect the surgical outcomes of patients with cervical spondylotic myelopathy (CSM) after laminoplasty. A total of 85 patients with CSM who underwent unilateral open-door laminoplasty between January 2013 and May 2017 were retrospectively reviewed. Based on preoperative T1 slope and C2-C7 lordosis matching, the patients were divided into 2 groups: the match group and the mismatch group. The T1 slope minus C2-C7 lordosis (T1S-CL) <20° was defined as matching. Radiographic parameters included T1 slope, C2-C7 lordosis, C2-C7 sagittal vertical axis (SVA), and T1S-CL. Clinical outcomes were based on the Neck Disability Index (NDI) and Japanese Orthopedic Association (JOA) scores. The preoperative T1S-CL had significant correlation with T1 slope (r= 0.283), C2-C7 lordosis (r= -0.611), and C2-C7 SVA (r= 0.331). At the final follow-up, patients in the mismatch group had a higher incidence of postoperative cervical kyphosis (P= 0.007) and C2-C7 SVA >40 mm (P= 0.043). The mismatch group also had greater △C2-C7 lordosis (P= 0.028), △C2-C7 SVA (P=0.042), and △T1S-CL (P= 0.044). Comparison of clinical outcomes revealed that patients in the match group had better NDI and JOA recovery (P < 0.05). T1S-CL is a clinically relevant parameter for surgical decision making because patients with T1S-CL mismatching are more likely to have postoperative kyphotic alignment changes and cervical sagittal imbalance. Laminoplasty might not be a suitable option for patients with T1S-CL mismatching.

Postoperative Resolution of Magnetic Resonance Imaging Signal Intensity Changes and the Associated Impact on Outcomes in Degenerative Cervical Myelopathy: Analysis of a Global Cohort of Patients.

Subanalysis of the prospective AOSpine CSM North America and International studies. To describe the postoperative changes in magnetic resonance imaging (MRI) spinal cord signal intensity in degenerative cervical myelopathy (DCM) patients and to investigate the impact of its postoperative resolution on clinical outcomes. When examining the spinal cord, hyperintensity found in MRI T2-weighted images and hypointensity in T1-weighted images are known to correlate with preoperative severity of DCM and to predict postoperative neurological recovery. However, the clinical importance of these signal intensity changes in postoperative images has not been established. Among 757 surgical DCM patients enrolled in two prospective multicenter studies, postoperative MRI images obtained between 6 and 24 months after the operation were examined with a focus on T2 hyper- and T1 hypointensity in the spinal cord. The 2-year postoperative Nurick grade, modified Japanese Orthopaedic Association score and modified Japanese Orthopaedic Association recovery rate (RR) were analyzed between patients with or without resolution of signal intensity changes. A total of 167 patients with preoperative T2 hyperintensity were included with complete postoperative MRI images. Of these patients, 11% showed resolution of signal intensity changes, 70% retained T2 hyperintensity only, and 19% showed both T2 hyper- and T1 hypointensity postoperatively. There was a stepwise trend toward worse postoperative outcomes, with the no signal intensity change group showing the best outcome and the T1 hypointensity group showing the worst (mean RR: 72% vs. 51% vs. 36%, P = 0.02). Patients who exhibited resolution of T2 hyperintensity showed better outcomes than those who retained it (RR: 72% vs. 47%, P = 0.04), but the resolution of T1 hypointensity was not associated with improved outcomes (RR: 38% vs. 26%, P = 0.36). Postoperative resolution of T2 hyperintensity in patients with DCM was associated with the best clinical outcomes, whereas those with T1 hypointensity showed the worst. 3.

Is high T-1 slope a significant risk factor for developing interlaminar bony fusion after cervical laminoplasty? A retrospective cohort study.

OBJECTIVE Several investigators have reported the occurrence of interlaminar bony fusion after cervical laminoplasty, which is reportedly associated with reduced postoperative cervical range of motion (ROM). However, to the authors' knowledge, no previous study has investigated the characteristics of patients who were likely to develop interlaminar bony fusion after cervical laminoplasty. Therefore, the objective of this study was to investigate the risk factors for interlaminar bony fusion in patients with cervical spondylotic myelopathy (CSM) following cervical laminoplasty and to investigate the effect of interlaminar bony fusion on surgical outcomes. METHODS The authors retrospectively reviewed data from 92 patients with CSM (63 men and 29 women) after cervical laminoplasty. The presence of interlaminar bony fusion was evaluated by functional radiographs 2 years after surgery. The patients were divided into 2 groups according to the presence of postoperative interlaminar bony fusion: a fusion group (at least 1 new postoperative interlaminar bony fusion) and a nonfusion group (no new interlaminar bony fusion). Potential risk factors for postoperative interlaminar bony fusion were assessed, including diabetes mellitus, smoking status, whether the C-2 lamina was included in the surgical treatment, C2-7 Cobb angle in each cervical position, preoperative cervical ROM, and T-1 slope. The differences in each variable were compared between the fusion and nonfusion groups. Thereafter, multivariate logistic regression analysis was performed to identify the risk factors for postoperative interlaminar bony fusion. For surgical outcomes, the recovery rate based on Japanese Orthopaedic Association scores and the reduction rate of cervical ROM were evaluated 2 years after surgery. RESULTS Interlaminar bony fusion was observed in 60 cases, 52 of which were observed at the C2-3 level. Patients in the fusion group were significantly older, had a significantly larger C2-7 angle in flexion, and had a significantly lower preoperative cervical ROM than those in the nonfusion group. A high T-1 slope was significantly more frequent in the fusion group. Multivariate analysis revealed that the significant risk factors for postoperative interlaminar bony fusion were high T-1 slope (odds ratio 4.81; p = 0.0015) and older age (odds ratio 1.05; p = 0.025). The Japanese Orthopaedic Association recovery rate in patients with interlaminar bony fusion did not differ significantly from those without bony fusion (45% vs 48%; p = 0.73). However, patients with bony fusion showed significantly reduced postoperative cervical ROM compared with those without bony fusion (50% vs 25%; p < 0.001). CONCLUSIONS High T-1 slope and older age were significant risk factors for developing interlaminar bony fusion after cervical laminoplasty in patients with CSM. Interlaminar bony fusion was associated with reduced postoperative cervical ROM, but it did not affect neurological outcomes.

Distraction Arthrodesis of the C1-C2 Facet Joint with Preservation of the C2 Root for the Management of Intractable Occipital Neuralgia Caused by C2 Root Compression.

Prospective observational cohort study. To compare the outcomes of our new technique, distraction arthrodesis of C1-C2 facet joint with C2 root preservation (Study group), to those of conventional C1-C2 fusion with C2 root transection (Control group) for the management of intractable occipital neuralgia caused by C2 root compression. We are not aware of any report concerning C2 root decompression during C1-C2 fusion. Inclusion criteria were visual analogue scale (VAS) score for occipital neuralgia 7 or more; C2 root compression at the collapsed C1-C2 neural foramen; and follow-up 12 months or more. The Study group underwent surgery with our new technique including (1) C1-C2 facet joint distraction and bone block insertion while preserving the C2 root; and (2) use of C1 posterior arch screws instead of conventional lateral mass screws during C1-C2 segmental screw fixation. The Control group underwent C2 root transection with C1-C2 segmental screw fixation and fusion. We compared the prospectively collected outcomes data. There were 15 patients in the Study group and 8 in the Control group. Although there was no significant difference in the VAS score for the occipital neuralgia between the 2 groups preoperatively (8.2 ± 0.9 vs. 7.9 ± 0.6, P = 0.39), it was significantly lower in the Study group at 1, 3, and 6 months postoperatively (P < 0.01, respectively). At 12 months, it was 0.4 ± 0.6 versus 2.5 ± 2.6 (P = 0.01). There was no significant difference in improvement in the VAS score for neck pain and neck disability index and Japanese Orthopedic Association recovery rate, which are minimally influenced by occipital neuralgia. Our novel technique of distraction arthrodesis with C2 root preservation can be an effective option for the management of intractable occipital neuralgia caused by C2 root compression.

Lumbar Spinous Process Splitting Decompression Provides Equivalent Outcomes to Conventional Midline Decompression in Degenerative Lumbar Canal Stenosis

Prospective, randomized controlled study. To compare the functional outcomes and extent of paraspinal muscle damage between 2 decompressive techniques for lumbar canal stenosis. Lumbar spinous process splitting decompression (LSPSD) preserves the muscular and liga-mentous attachments of the posterior elements of the spine. It can potentially avoid problems such as paraspinal muscle atrophy and trunk extensor weakness that can occur after conventional midline decompression. However, large series prospective randomized controlled studies are lacking. Patients with lumbar canal stenosis were randomly allocated into 2 groups: LSPSD (28 patients) and conventional midline decompression (23 patients). The differences in operative time, blood loss, time to comfortable mobilization, and hospital stay were studied. Paraspinal muscle damage was assessed by postoperative rise in creatine phosphokinase and C-reactive protein levels. Functional outcome was evaluated at 1 year by Japanese Orthopaedic Association score, neurogenic claudication outcome score, and visual analogue scale for back pain and neurogenic claudication. Fifty-one patients of mean age 56 years were followed-up for a mean 14.2 ± 2.9 months. There were no significant differences in the operative time, blood loss, and hospital stay. Both the groups showed significant improvement in the functional outcome scores at 1 year. Between the 2 groups, the Japanese Orthopaedic Association score, neurogenic claudication outcome score improvement, visual analogue scale for back pain, neurogenic claudication visual analogue scale, and the postoperative changes in serum C-reactive protein and creatine phosphokinase levels did not show any statistically significant difference. On the basis of the Japanese Orthopaedic Association recovery rate, it was found that 73.9% of conventional midline decompression group had good outcomes compared with only 60.7% after LSPSD. The functional outcome scores, back pain, and claudication pain in the immediate period and at the end of 1 year are similar in both the techniques. More patients had better functional outcomes after conventional decompression than the LSPSD technique. On the basis of this study, the superiority of one technique compared with the other is not established, mandating the need for further long-term studies. 2.

Effectiveness of 3 Surgical Decompression Strategies for Treatment of Multilevel Cervical Myelopathy in 3 Spinal Centers in China

Retrospective multicenter study. To compare clinical outcomes and surgical-related adverse events in patients with multilevel cervical myelopathy (MCM) undergoing simple anterior, simple posterior, or 1-stage posterior-anterior surgical decompression strategies. Simple anterior, simple posterior, and 1-stage posterior-anterior surgical decompression strategies have been advocated for MCM treatment in both Western and Chinese populations. However, there is limited evidence on whether 1-stage posterior-anterior strategy may offer equal or more advantages than the other 2 strategies for patients with MCM. A retrospective review of medical records was conducted for 255 patients with MCM who had undergone surgical decompression in 3 Chinese spinal centers from 1999 to 2010. Neurological status, perioperative variables, and surgical complications were assessed. Multiple linear regression was used to evaluate factors associated with the outcomes of each strategy. Analyses were conducted on a total of 229 patients with MCM undergoing surgical decompression via 1-stage posterior-anterior (68 patients), simple anterior (102 patients), and simple posterior approaches (59 patients). One-stage posterior-anterior approach had the highest Japanese Orthopaedic Association recovery rate after adjusted for age and sex (adjusted mean ± SD: 50.0 ± 3.2, P < 0.001) and additionally adjusted for smoking, duration from onset of symptoms to surgery, comorbidities, preoperative Japanese Orthopaedic Association score, Ishihara's curvature index and Pavlov ratio, operative blood loss, operating time, anterior operated disc levels, and posterior operated levels (adjusted mean ± SD: 51.6 ± 11.6, P < 0.01). Anterior approach had the largest difference between the pre- and postoperative Ishihara's curvature indexes after adjusted for age and sex (adjusted mean ± SD: 5.3 ± 1.0, P < 0.01) and after multivariable adjustment (adjusted mean ± SD: 6.5 ± 2.8, P = 0.003). One-stage posterior-anterior strategy can be a reliable and effective treatment strategy for MCM in a subgroup of patients with anterior and posterior compression on spinal cord simultaneously.

Impact of deep extensor muscle-preserving approach on clinical outcome of laminoplasty for cervical spondylotic myelopathy: comparative cohort study

This study aimed to compare patients undergoing deep extensor muscle-preserving laminoplasty and conventional open-door laminoplasty for the treatment of cervical spondylotic myelopathy (CSM). We specifically assessed axial pain, cervical spine function, and quality of life (QOL) with a minimum follow-up period of 3 years. Ninety patients were divided into two groups and underwent either conventional open-door laminoplasty (CL group) or laminoplasty using the deep extensor muscle-preserving approach (MP group). The latter approach was undertaken by preserving the multifidus and semispinalis cervicis attachments followed by open-door laminoplasty and resuturing of the bisected spinous processes at each decompression level. The mean follow-up period was 7.7 years (range, 36-128 months). Preoperative and follow-up evaluations included the Japanese Orthopaedic Association (JOA) score, a tentative version of the JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) including cervical spine function and QOL, and a visual analog scale (VAS) for axial pain. Radiological analyses included cervical lordosis and flexion-extension range of motion (C2-7), as well as deep extensor muscle areas on axial magnetic resonance imaging (MRI). The mean number of decompressed laminae was 3.9 and 3.3 in CL and MP groups, respectively, which was statistically equivalent. Japanese Orthopaedic Association recovery was statistically equivalent between the two groups. The MP group demonstrated a superior QOL score (57 vs. 46%) compared with the CL group at final follow-up (p < 0.05). Mean VAS scores at final follow-up were 2.2 and 4.3 in MP and CL groups, respectively (p < 0.05). Cervical lordosis and flexion-extension range of motion were statistically equivalent. The percentage deep muscle area on MRI was significantly lesser in the CL group compared with the MP group (58 vs. 102%; p < 0.01). We demonstrated the superiority of deep extensor muscle-preserving laminoplasty in terms of postoperative axial pain, QOL, and prevention of atrophy of the deep extensor muscles over conventional open-door laminoplasty for the treatment of CSM.

Ossification of the ligamentum flavum of the thoracic spine in the Korean population

Thoracic ossification of the ligamentum flavum (OLF), a main cause of thoracic myelopathy, is an uncommon disease entity. It is seen mostly in East Asia, although the majority of reports have issued from Japan. In the present study, the clinical features and prognostic factors of thoracic OLF were examined in a large number of Korean patients. Data from 51 consecutive patients who underwent decompressive laminectomy with or without fusion for thoracic OLF between 1998 and 2008 were retrospectively analyzed. Patients were evaluated pre- and postoperatively using the modified Japanese Orthopedic Association (JOA) scale (maximum total score of 11). Patient age, sex, preoperative symptoms, duration of initial symptoms, number of involved segments, duration of follow-up, presence of dural adhesion (dural tearing), intramedullary high signal intensity, morphological classification of OLF (axial or sagittal), coexisting disease, and fusion or no fusion were also evaluated. Surgical outcomes were assessed using JOA recovery rate/outcome scores, and patient satisfaction grades and prognostic factors were analyzed. There were 18 men and 33 women with a mean age of 60.9 years (range 38-80 years). A mean preoperative JOA score of 5.5 improved to a mean score of 7.4 at the last follow-up (mean 52 months after surgery). The mean duration of the initial symptoms was 34.5 months (range 0.1-240 months) prior to surgery. The most common symptoms were motor dysfunction (80%); sensory deficit (67%); and pain, numbness, and claudication (59%) in the lower extremities. Knee hyperreflexia appeared in 69% of the patients. There were a total of 130 ossified segments, and the mean number of segments per patient was 2.6. Ninety-two (71%) of 130 segments were located below T-8. Recovery outcomes were good (18 patients), fair (16 patients), unchanged (11 patients), or worse (6 patients). Thirty-one patients (61%) were satisfied with their operations. Patients with a beak type of OLF on sagittal MR images experienced a higher recovery rate and a better satisfaction grade than did those with a round OLF. The patients with higher preoperative JOA scores demonstrated significantly higher JOA scores postoperatively (p < 0.001), and the preoperative JOA score had a significant correlation with the recovery rate in patients exhibiting mainly motor dysfunction (p = 0.040, r = 0.330). Of the thoracic OLF studies published to date, the present analysis involves the largest Korean population. The most common symptoms of thoracic OLF were motor dysfunction and sensory deficit in the lower extremities, although pain, numbness, and claudication were observed in some patients and were notably accompanied by knee hyperreflexia. At a minimum of 2 years after surgery for thoracic OLF, operative outcomes were generally good, and the prognostic factors affecting good surgical outcomes included a beak type of OLF and a preoperative JOA score > 6.

Subsidence of Titanium Mesh Cage

A cohort study. To clarify the risk factors for the subsidence of the titanium mesh cage (TMC) after anterior cervical corpectomy and fusion, and to discuss their clinical correlations. Fusion with TMC after anterior cervical corpectomy has become popular as an established treatment for cervical degenerative diseases, but postoperative TMC subsidence has often been reported in the literature. A total of 300 patients with anterior cervical corpectomy and TMC fusion were included in the study, including 1-level corpectomy in 236 patients and 2-level corpectomy in 64. TMC subsidence, radiologic findings, and clinical results were evaluated in the 12-month follow-up period. TMC subsidence occurred in 239 (79.7%) cases, including mild subsidence (1 to 3 mm) in 182 (60.7%) and severe subsidence (>3 mm) in 57 (19.0%). Two-level corpectomy was more susceptible to severe subsidence, when compared with 1-level corpectomy (P<0.001). Japanese Orthopedic Association recovery rate for severe subsidence was significantly lower than that for no subsidence (P=0.010). Severe subsidence was correlated with subsidence-related complications, including neck pain, neurologic deterioration, and instrument failure. TMC subsidence was a common phenomenon after anterior cervical corpectomy and fusion with TMC. Level of corpectomy was a unique risk factor for severe subsidence in this study, which might have led to bad clinical results and subsidence-related complications.