Degenerative Lumbar Scoliosis Group Research Articles

Prognostic Factors of Surgical Outcome after Spinous Process-Splitting Laminectomy for Lumbar Spinal Stenosis.

Study DesignA retrospective case review.PurposeTo assess the clinical and radiographic outcomes and identify the predictive factors associated with poor clinical outcomes after lumbar spinous process-splitting laminectomy (LSPSL) for lumbar spinal stenosis (LSS).Overview of LiteratureLSPSL is an effective surgical treatment for LSS. Special care should be taken in patients with degenerative lumbar scoliosis (DLS).MethodsA consecutive retrospective case review of patients undergoing LSPSL for LSS with a minimum 2-year follow-up was performed. Mild DLS and mild degenerative spondylolisthesis (DS) were included in the study. The Japanese Orthopedic Association (JOA) score and recovery rate were reviewed. Poor clinical outcome was defined as a recovery rate <50% using Hirabayashi's method.ResultsA total of 52 patients (mean age, 72 years) met the inclusion criteria and had a mean follow-up of 2.6 years (range, 2-4.5 years). The preoperative diagnosis was LSS in 19, DS in 19, and DLS in 14 cases. The mean JOA score significantly increased from 14.6 to 23.2 at the final follow-up. The overall mean recovery rate was 60.1%. Thirteen patients (25%) were assigned to the poor outcome group. A higher rate of pre-existing DLS was observed in the poor outcome (poor) group (good, 15%; poor, 62%; p=0.003) than in the good outcome (good) group. None of the patient factors examined were associated with a poor outcome. A progression of slippage ≥5 mm was found in 8 of 24 patients (33%) in the DS group. A progression of curvature ≥5° was found in 5 of 14 patients (36%) in the DLS group. The progression of scoliosis and slippage did not influence the clinical outcome.ConclusionsThe clinical and radiographic outcomes of LSPSL for LSS were favorable. Pre-existing DLS was significantly associated with poor clinical outcome.

Radiographic Evaluation of Segmental Motion of Scoliotic Wedging Segment in Degenerative Lumbar Scoliosis

A cross-sectional study. To evaluate the segmental instability of wedging segments using dynamic films and the impact of osteophyte formation on segmental motion in degenerative lumbar scoliosis (DLS). Evaluation of segmental instability in DLS is essential for spinal surgery to make the decision "fusion or not fusion." Some previous studies have shown radiographic data regarding segmental instability in DLS. However, little is known about segmental motion of wedging segments in DLS. A total of 101 patients complaining of neurogenic claudication owing to lumbar spinal canal stenosis (LCS) were enrolled and divided into 2 groups based on their coronal spinal deformity; Cobb angle of >10 degree (DLS group) or <10 degree (LCS group). The following parameters were measured on anteroposterior films: lateral translation, degree of osteophyte formation, and range of motion (ROM) in lateral bending films. The facet joint space discrepancy was measured on computed tomography images. The radiographic parameters were compared between 85 wedging segments (>5 degrees) in DLS group and 150 nonwedging segments in LCS group. Mean lateral translation was significantly greater in the DLS group (P<0.01 for each level). Average joint space discrepancy was significantly greater in the DLS group (P<0.01 at L2/3 and L3/4, P =0.01 at L4/5). ROM was significantly greater in the DLS group with the same degree osteophyte formation. Degree of osteophyte formation was inversely correlated with ROM in the DLS group (R(2)=0.5696). The present study indicated that wedging segments in DLS had greater motion than nonwedging segments in LCS. However, the osteophyte formation provided restabilization for the wedging segments in DLS, suggesting that evaluation of osteophyte formation is an important factor in surgical decision making for DLS.

Asymmetric Degeneration of Paravertebral Muscles in Patients With Degenerative Lumbar Scoliosis

A prospective observational study. To evaluate the paravertebral muscle (PVM) degeneration in patients with degenerative lumbar scoliosis (DLS), using magnetic resonance imaging. Several studies have described the histological and morphological changes to the PVM in patients with chronic low back pain and lumbar radiculopathy. However, there is little knowledge about the PVM changes in patients with DLS. Fifty-seven patients with lumbar spinal stenosis (LSS) with DLS (DLS group) and 50 control patients with LSS without DLS (LSS group) were examined. The cross-sectional area (CSA) and percentage of fat infiltration area (%FIA) of the bilateral multifidus and longissimus muscles at the L1-S1 levels were measured using T2-weighted axial magnetic resonance imaging and computer software. A multifidus muscle biopsy and histological evaluation were performed in some patients. In the DLS group, the CSA of the multifidus muscle was significantly smaller and the %FIA of both muscles was significantly higher on the concave side than on the convex side at all levels (P < 0.0001 for each). These differences were also found in the longissimus muscles at the L4-L5 and L5-S1 levels (P < 0.0001 for each). Histologically, the multifidus muscle exhibited reductions in the muscle fiber size and number of nuclei on the concave side. In the LSS group, the total CSA and %FIA did not differ significantly between the left and right sides. However, in patients with unilateral radiculopathy, the CSA of the multifidus muscle was significantly smaller (P < 0.05) and the %FIA of both muscles was significantly higher (P < 0.05) on the symptomatic side, especially at 1 level below. This observational study with magnetic resonance imaging and histology showed that muscle degeneration was more common on the concave side in patients with DLS. Radiculopathy and spinal deformity may contribute to the PVM degeneration.

Genetic Predisposition in Degenerative Lumbar Scoliosis due to the Copy Number Variation

Comparative genomic hybridization (CGH) microarrays. To identify genomic copy number variations (CNVs) in degenerative lumbar scoliosis (DLS) patients, and investigate the possibility of genetic predisposition in DLS. Genome scanning technology enables search for presence of CNVs. CGH microarray is a useful procedure in a genome-wide study. Among 45 consecutive patients who were diagnosed as DLS, 15 patients who manifested greatest Cobb's angle were selected for the array-CGH based CNV analysis. Control group was blood samples from 58 individuals without DLS. Oligonucleotide CGH microarray was utilized to analyze the CNV. Gene searches were performed for CNV DNA with significant gene-dosage difference. Validation qualitative PCR(qPCR) was performed at 3 genetic loci: at chromosome 2--TMEM163 gene, at chromosome 16--ANKRD 11 gene, and at chromosome 18--NFATC1 gene. Genomic gains and losses were observed using the oligonucleotide CGH microarray. Identified CNVs were 446 ± 129 per individual. Gain- and loss-CNVs were identified as 196 ± 24 and 250 ± 110, respectively. The length of total CNV per individual was 30,946,730 ± 31,658,175 bp, and mean CNV-length was 61,017 ± 40,620 (median length 6411 ± 1994). Comparison with control group revealed 260 CNVs, which were significant (P < 10(-3)). Validation qPCR for gene-dosage comparison of DLS group DNA versus control group DNA in TMEM163 (P < 0.001); ANKRD 11 (P = 0.000); and NFATC1 (P = 0.000) gene showed significant difference. Various whole-genome CNVs specific to DLS patients were observed. Validation qPCR confirmed significantly different gene-dosages for TMEM163, ANKRD 11, and NFATC1 genes. We consider that the expression of DLS is supported by various typical CNV-associated structural variants of the genome.

The influence of approach side on facet preservation in microscopic bilateral decompression via a unilateral approach for degenerative lumbar scoliosis

The authors compared the clinical outcomes of microscopic bilateral decompression via a unilateral approach (MBDU) for the treatment of degenerative lumbar scoliosis (DLS) and for lumbar canal stenosis (LCS) without instability. The authors also compared postoperative spinal instability in terms of different approach sides (concave or convex) following the procedure. The authors retrospectively reviewed data obtained in 50 consecutive patients (25 in the DLS group and 25 in the LCS group) who underwent MBDU; the minimum follow-up period was 2 years. Patients with DLS were divided into 2 subgroups according to the surgical approach side: a concave group (23 segment) and a convex group (17 segments). The Japanese Orthopaedic Association Scale scores for the assessment of low-back pain were evaluated before surgery and at final follow-up. The Japanese Orthopaedic Association Scale scores and recovery rates were compared between the DLS and LCS groups, and between the convex and concave groups. Cobb angle and scoliotic wedging angle (SWA) were evaluated on standing radiographs before surgery and at final follow-up. Facet joint preservation (the percentage of preservation) was assessed on pre- and postoperative CT scans, compared between the LCS and DLS groups, and compared between the concave and convex groups. The influence of approach side on postoperative progression of segmental instability was also examined in the DLS group. The mean recovery rate was 58.7% in the DLS and 62.0% in the LCS group. The mean recovery rate was 58.6% in the convex group and 60.6% in the concave group. There were no significant differences in recovery rates between the LCS and DLS groups, or between the DLS subgroups. The mean Cobb angles in the DLS group were significantly increased from 12.7° preoperatively to 14.1° postoperatively (p < 0.05), and mean preoperative SWAs increased significantly from 6.2° at L3-4 and 4.1° at L4-5 preoperatively to 7.4° and 4.9°, respectively, at final follow-up (p < 0.05). There was no significant difference in percentage of preservation between the DLS and LCS groups. The mean percentages of preservation on the approach side in the DLS group at L3-4 and L4-5 were 89.0% and 83.1% in the convex group, and those in the concave group were 67.3% and 77.6%, respectively. The percentage of preservation at L3-4 was significantly higher in the convex than the concave group. The mean SWA had increased in the concave group (p = 0.01) but not the convex group (p = 0.15) at final follow-up. The MBDU can reduce postoperative segmental spinal instability and achieve good postoperative clinical outcomes in patients with DLS. The convex approach provides surgeons with good visibility and improves preservation of facet joints.