Surgical treatment of nerve root compression caused by scoliosis of the lumbar spine

Myelin protein zero mutation-related hereditary neuropathies: Neuropathological insight from a new nerve biopsy cohort

Myelin protein zero (MPZ/P0) is a major structural protein of peripheral nerve myelin. Disease-associated variants in the MPZ gene cause a wide phenotypic spectrum of inherited peripheral neuropathies. Previous nerve biopsy studies showed evidence for subtype-specific morphological features. Here, we aimed at enhancing the understanding of these subtype-specific features and pathophysiological aspects of MPZ neuropathies. We examined archival material from two Central European centers and systematically determined genetic, clinical, and neuropathological features of 21 patients with MPZ mutations compared to 16 controls. Cases were grouped based on nerve conduction data into congenital hypomyelinating neuropathy (CHN; n = 2), demyelinating Charcot-Marie-Tooth (CMT type 1; n = 11), intermediate (CMTi; n = 3), and axonal CMT (type 2; n = 5). Six cases had combined muscle and nerve biopsies and one underwent autopsy. We detected four MPZ gene variants not previously described in patients with neuropathy. Light and electron microscopy of nerve biopsies confirmed fewer myelinated fibers, more onion bulbs and reduced regeneration in demyelinating CMT1 compared to CMT2/CMTi. In addition, we observed significantly more denervated Schwann cells, more collagen pockets, fewer unmyelinated axons per Schwann cell unit and a higher density of Schwann cell nuclei in CMT1 compared to CMT2/CMTi. CHN was characterized by basal lamina onion bulb formation, a further increase in Schwann cell density and hypomyelination. Most late onset axonal neuropathy patients showed microangiopathy. In the autopsy case, we observed prominent neuromatous hyperinnervation of the spinal meninges. In four of the six muscle biopsies, we found marked structural mitochondrial abnormalities. These results show that MPZ alterations not only affect myelinated nerve fibers, leading to either primarily demyelinating or axonal changes, but also affect non-myelinated nerve fibers. The autopsy case offers insight into spinal nerve root pathology in MPZ neuropathy. Finally, our data suggest a peculiar association of MPZ mutations with mitochondrial alterations in muscle.

Changes in the lumbar intervertebral foramen between supine and standing posture in patients with adult spinal deformity: a study with upright computed tomography

OBJECTIVE

To quantitatively assess the impact of supine and standing positions on the morphological changes in the lumbar intervertebral foramen (LIF) in patients with adult spinal deformity (ASD) using upright CT and conventional supine CT.

MATERIALS AND METHODS

Thirty patients with ASD were prospectively enrolled in this study. All subjects underwent standing whole spine posterior/anterior radiographs, lateral radiographs, and whole spine CT, both in the supine and upright standing positions. Two orthopedic surgeons independently measured nine radiographic parameters in the radiograph and the lumbar foraminal area (FA) and height (FH) in supine and upright CT. Statistical analyses were performed to evaluate the risk of LIF decrease when standing upright compared to the supine position. The chi-squared, t test, Pearson's coefficients, intra- and inter-rater reliabilities, and ROC curves were calculated. The level of significance was set at p < 0.05.

RESULTS

Among the 300 LIFs, both the lumbar FA and FH were either increased or decreased by > 5% in approximately 30% of LIFs each. The FA decreased in the lower lumbar spine. The concave side had a significantly higher rate of decreased FA and FH than the convex side (p < 0.05 and < 0.05, respectively). ROC analysis showed that narrowing of the intervertebral disc (cutoff > 0.05°) is a risk factor for decreased FA and FH.

CONCLUSIONS

This study describes the details of the changes in the neuroforamen using a novel upright CT. In patients with ASD, approximately 30% of LIFs either increased or decreased in size by > 5% when standing. The risk factors for LIF decrease are the lower lumbar spine, concave side, and narrow side of the disc wedge.

Radiologic and Clinical Courses of Degenerative Lumbar Scoliosis (10°-25°) after a Short-Segment Fusion

Study Design

Retrospective study.

Purpose

We report the surgical outcomes of small degenerative lumbar scoliosis (DLS) patients treated by a short-segment fusion and followed for a minimum of 5 years.

Overview of Literature

Several surgical options are available for the treatment of DLS, such as decompression only, decompression plus a short-segment fusion, or decompression with a long segment fusion. Few studies have evaluated the results of a short-segment fusion in patients with DLS over time.

Methods

Seventy small DLS patients (Cobb's angle, 10°–25°) with a minimum follow-up of 5 years were treated with a short-segment fusion between March 2004 and February 2010. The mean patient age was 71 (male:female=16:54), with a follow-up of 6.5 years (range, 5.0–11.6). The Cobb's angle, 1 and 2 segment coronal upper intervertebral angle, 1 and 2 segment sagittal upper intervertebral angle, the lumbar lordosis angle, and the C7 plumb lines (coronal and sagittal) were evaluated using simple radiographs, and visual analog scale (VAS), back pain was assessed preoperatively, immediately after surgery, and at 3, 6, and 12 months and 3 and 5 years after surgery. To identify factors influencing the radiologic progression, age, number of fusion segments, vertebral levels of fusion, body mass index, lowest instrumented vertebra (L5 or S1), bone mineral density (>–2.5, ≤–2.5), and the presence of an interbody fusion were analyzed.

Results

The Cobb's angle and 1 segment coronal upper intervertebral angle showed more progression during follow up, particularly at 6 and 12 months after surgery. Clinical outcomes and radiological results were found to be significantly associated (p=0.041). No statistically significant association was found between other factors affecting radiologic progression from postoperative 6 months to 1 year.

Conclusions

Radiologic variables (the Cobb's angle and coronal upper intervertebral angle–1) should be carefully considered and clinical caution exercised from 6 to 12 months after short-segment fusion in small DLS (10°–25°).

Minimally invasive decompression surgery for lumbar spinal stenosis with degenerative scoliosis: Predictive factors of radiographic and clinical outcomes

There is ongoing controversy regarding the most appropriate surgical treatment for lumbar spinal stenosis (LSS) with concurrent degenerative lumbar scoliosis (DLS): decompression alone, decompression with limited spinal fusion, or long spinal fusion for deformity correction. The coexistence of degenerative stenosis and deformity is a common scenario; Nonetheless, selecting the appropriate surgical intervention requires thorough understanding of the patients clinical symptomatology as well as radiographic parameters. Minimally invasive (MIS) decompression surgery was performed for LSS patients with DLS. The aims of this study were (1) to investigate the clinical outcomes of MIS decompression surgery in LSS patients with DLS, and (2) to identify the predictive factors for both radiographic and clinical outcomes after MIS surgery. 438 consecutive patients were enrolled in this study. Inclusion criteria was evidence of LSS and DLS with coronal curvature measuring greater than 10°. The Japanese Orthopaedic Association (JOA) score, JOA recovery rate, low back pain (LBP), and radiographic features were evaluated preoperatively and at over 2 years postoperatively. Of the 438 patients, 122 were included in final analysis, with a mean follow-up of 2.4 years. The JOA recovery rate was 47.6%. LBP was significantly improved at final follow-up. Cobb angle was maintained for 2 years postoperatively (p = 0.159). Clinical outcomes in foraminal stenosis patients were significantly related to sex, preoperative high Cobb angle and progression of scoliosis (p = 0.008). In the severe scoliosis patients, the JOA recovery was 44%, and was significantly depended on progression of scoliosis (Cobb angle: preoperation 29.6°, 2-years follow-up 36.9°) and mismatch between the pelvic incidence (PI) and the lumbar lordosis (LL) (preoperative PI-LL 35.5 ± 21.2°) (p = 0.028). This study investigated clinical outcomes of MIS decompression surgery in LSS patients with DLS. The predictive risk factors of clinical outcomes were severe scoliosis, foramina stenosis, progressive scoliosis and large mismatch of PI-LL.

Curve Characteristics and Foraminal Dimensions in Patients With Adult Scoliosis and Radiculopathy

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To demonstrate a correlation between radiculopathy symptoms, foraminal morphology, and curve types.

SUMMARY OF BACKGROUND DATA

Patients with degenerative scoliosis frequently present with foraminal stenosis and radiculopathy, the origin of which is not well understood.

METHODS

A total of 48 patients (384 foraminas) were included: 14 with low back pain (B); 16 with femoral nerve pain (F); and 18 with sciatic nerve pain (S). The symptomatic foramen of groups F and S were compared with asymptomatic foramina. Alignment was measured from standardized radiographs; 3D-CT reconstructions were used to measure foraminal height and area. Data are presented as mean±SD. The χ, t test, and Pearson coefficients were calculated; as well as interobserver and intraobserver reproducibility (Cohen κ).

RESULTS

Seventeen of the 18 patients with sciatic nerve pain (S) presented foraminal stenosis (<40 mm) at the concavity of the fractional curve distal to the main lumbar structural curve. The symptomatic foramina were significantly smaller in height (7.8±2.5 vs. 12.1±3.1 mm, P<0.0001) and area (30.1±14.3 vs. 57.6±28.7 mm, P<0.0001) compared with asymptomatic foramen; 7/7 patients with femoral nerve pain (F) and lumbar structural curves (apex L3 or lower) had foraminal stenosis at the concavity of the fractional curve. Eight of the 9 patients with femoral nerve pain (F) and thoracic, thoracolumbar, or lumbar (apex L2 or higher) curves, presented foraminal stenosis in the concavity of the caudal fractional curve. The symptomatic foraminal spaces were significantly smaller in height (9.2±3.2 vs. 12.1±3.1 mm, P<0.0001) and area (30.1±15.2 vs. 57.6±28.7 mm, P<0.0001). Foraminal height correlated with foraminal area (r=0.68-0.85; P<0.0001). Interobserver agreement was between 0.6092 and 0.8679.

CONCLUSIONS

A correlation between curve types and symptomatic foraminal stenosis exists. Adult scoliosis patients with sciatic nerve pain typically present with foraminal stenosis at the concavity of the caudal fractional curve. Similarly, patients with femoral nerve pain present with foraminal stenosis at the concavity of the caudal fractional curve when the main structural curve is thoracic, thoracolumbar, or lumbar (apex L2 or higher).

Can decompression surgery relieve low back pain in patients with lumbar spinal stenosis combined with degenerative lumbar scoliosis?

INTRODUCTION

Decompression with fusion is usually recommended in patients with lumbar spinal stenosis (LSS) combined with degenerative lumbar scoliosis (DLS). However, elderly patients with LSS and DLS often have other comorbidities, and surgical treatment must be both safe and effective. The aim of this study was to investigate whether decompression surgery alone alleviates low back pain (LBP) in patients with LSS and DLS, and to identify the predictors of postoperative residual LBP.

MATERIALS AND METHODS

A total of 75 patients (33 males and 42 females) with a mean age of 71.8 years (range 53-86 years) who underwent decompression surgery for LSS with DLS (Cobb angle ≥ 10°) and had a minimum follow-up period of 1 year, were retrospectively reviewed using the Japanese Orthopaedic Association scoring system for the assessment of lumbar spinal diseases (JOA score). Radiographic measurements included coronal and sagittal Cobb angles, apical vertebral rotation (Nash-Moe method), and anteroposterior and lateral spondylolisthesis. Logistic regression analysis was performed to investigate the predictors of residual LBP after surgery.

RESULTS

Forty-nine patients had preoperative LBP, of which 29 (59.1 %) experienced postoperative relief of LBP. Logistic regression analysis demonstrated that the degree of apical vertebral rotation on preoperative radiography was significantly associated with postoperative residual LBP (odds ratio, 8.16, 95 % confidence interval, 1.55-83.81, p = 0.011).

CONCLUSION

A higher degree of apical vertebral rotation may therefore be an indicator of mechanical LBP in patients with LSS and DLS. Decompression with fusion should be recommended in these patients.

Prevalence, Severity, and Impact of Foraminal and Canal Stenosis Among Adults With Degenerative Scoliosis

BACKGROUND

Management approaches for adult scoliosis are primarily based on adults with idiopathic scoliosis and extrapolated to adults with degenerative scoliosis. However, the often substantially, but poorly defined, greater degenerative changes present in degenerative scoliosis impact the management of these patients.

OBJECTIVE

To assess the prevalence, severity, and impact of canal and foraminal stenosis in adults with degenerative scoliosis seeking operative treatment.

METHODS

A prospectively collected database of adult patients with deformity was reviewed for consecutive patients with degenerative scoliosis seeking surgical treatment, without prior corrective surgery. Patients completed the Oswestry Disability Index, SF-12, Scoliosis Research Society 22 questionnaire, and a pain numeric rating scale (0–10). Based on MRI or CT myelogram, the central canal and foraminae from T6 to S1 were graded for stenosis (normal or minimal/mild/moderate/severe).

RESULTS

Thirty-six patients were included (mean age, 68.9 years; range, 51–85). The mean leg pain numeric rating scale was 6.5, and the mean Oswestry Disability Index score was 53.2. At least 1 level of severe foraminal stenosis was identified in 97% of patients; 83% had maximum foraminal stenosis in the curve concavity. All but 1 patient reported significant radicular pain, including 78% with discrete and 19% with multiple radiculopathies. Of those with discrete radiculopathies, 76% had pain corresponding to areas of the most severe foraminal stenosis, and 24% had pain corresponding to areas of moderate stenosis.

CONCLUSION

Significant foraminal stenosis was prevalent in patients with degenerative scoliosis, and the distribution of leg pain corresponded to levels of moderate or severe foraminal stenosis. Failure to address symptomatic foraminal stenosis when surgically treating adult degenerative scoliosis may negatively impact clinical outcomes.

Characteristics of nerve root compression caused by degenerative lumbar spinal stenosis with scoliosis

BACKGROUND CONTEXT

In degenerative lumbar spinal stenosis with scoliosis (DLS), many authors stated that nerve root compression is almost always seen on the concave side of the scoliosis, and L4 and L5 nerve roots are the most often involved. However, there are few reports on the relationship between nerve root compression and the pattern of scoliosis.

PURPOSE

To investigate the factors that may contribute to radiculopathy in DLS and their association with the pattern of the scoliosis.

STUDY DESIGN

Retrospective analysis.

METHODS

Twenty-two consecutive patients with DLS with radiculopathy were examined. The symptomatic nerve roots were determined by pain distribution, neurological findings and nerve root infiltration using lidocaine. The compressive factors were diagnosed by magnetic resonance imaging or myelography, discography, computed tomography after myelography or discography and radiculography. The pattern of scoliosis was determined in plain radiographs. We evaluated the correlation between the affected nerve root and the compressive factors or the pattern of the scoliosis.

RESULTS

The L3 root was affected in 23% of patients; L4 root in 68%, L5 root in 55% and S1 root in 18%. L3 and L4 roots were more compressed by foraminal or extraforaminal stenosis on the concave side of the curve, whereas L5 and S1 roots were commonly affected by lateral recess stenosis on the convex side. The Cobb angle and the lateral slip of the cases in which L3 or L4 root was affected were significantly larger than in cases in which L5 or S1 root was compressed.

CONCLUSIONS

In the treatment of radiculopathy caused by DLS, it is important to bear in mind that L3 or L4 roots were more strongly compressed by foraminal or extraforaminal stenosis at the concave side of the curve, whereas L5 or S1 nerve roots were affected more by lateral recess stenosis at the convex side of the curve.

One-stage three-dimensional correction and fusion: a multilevel posterior lumbar interbody fusion procedure for degenerative lumbar kyphoscoliosis. Technical note

Surgery for degenerative lumbar kyphoscoliosis (DLKS) is very challenging because the curve has become rigid due to circumferential osteoarthritic changes. Therefore, a standard procedure involving correction and fusion after decompression of the nerves has not yet been established. The authors have been searching for an effective procedure that provides adequate decompression and three-dimensional (3D) correction for symptomatic DLKS. In this report they describe a new 3D correction and fusion technique involving multilevel posterior lumbar interbody fusion. They analyze the results obtained in the first 23 cases and discuss the advantages and disadvantages of the procedure. The correction effect was excellent, and compared with other instrumentation-assisted procedures, this surgery is not remarkably invasive. Although the procedure is limited in achieving normal sagittal alignment and the acceleration rate of adjacent-disc degeneration remains relatively high, it is an option for the rigid deformity characterized by DLKS.

Anatomic issues related to cervical and lumbosacral radiculopathy

The anatomy of cervical and lumbar spinal nerves is well established. Knowledge of the normal and pathoanatomy of impingement of these roots is helpful in the diagnosis of radiculopathy in many cases. Frequently, symptoms and signs do not correlate with expected anatomical patterns. Variations of nerve roots, spinal nerves, and plexuses occur commonly. Neuroanatomical anomalies and musculoskeletal abnormalities account for many of the variations seen with unexpected radicular patterns. Unfortunately, the delineation of segmental innervation has been achieved by several different methods and definitive studies are lacking. Although there is a regular and orderly progression of innervation within each individual, it is likely that innervation patterns differ considerably between individuals.

Recent advances in the treatment of low back pain

There is at the present time an epidemic of low back pain in the industrialized countries. Although the exact origin of such pain is still unknown, there is increasing awareness that the outcome is usually favourable. Only some 10% of those suffering an acute episode of back pain are incapacitated for more than 6 weeks. The causes of long standing back pain are being identified in an increasing number of patients. They include anatomical and pathological disturbances in the motion segment as well as psychological, social and political causes. There are numerous factors which influence the pathophysiology of the motion segment. The degree of loading has been successfully measured and delineated for various postures and exercises, including those at work. The nutritional pathways to the disc have been established and the effect of various external factors measured. Movement is good for the disc and the importance of continuous passive motion for the healing of diseased or injured connective tissues is not established. Activation of large muscle groups increases the production of the body's pain reducing encephalins. Early diagnosis and early mobilisation of the patient should be of benefit, and long term bed rest and inactivity must be prevented. Fewer cases will need operation in the future. Improved imaging techniques and better methods of operation and fixation will help those few who have a definite pathological lesion amenable to surgery.

Progressive senile scoliosis: seven cases of increasing spinal curves in elderly patients

An increasing scoliosis was documented in seven elderly women. The average curve at the most recent examination was 43 degrees (range 26 degrees-78 degrees). Previous films, from 5 to 26 years before, demonstrated an average increase of 2.3 degrees/year (range 1 degree-4.8 degrees/year). There were three lumbar and four thoracolumbar curves. Three curves were to the right and four were to the left. Only one patient had osteoporotic vertebral body crush fractures. The common underlying mechanism in the progression of senile scoliosis appears to be asymmetric loading of the spine which can be caused by a previously established scoliosis, spondylolysis/spondylolisthesis, lumbosacral anomalies, or leg length discrepancy. Subsequently, factors that can cause a curve to increase include degenerative disc disease with lateral disc space narrowing, soft tissue failure, and osteoporosis. Since even minor scoliosis can potentially progress in the older adult, increased monitoring of scoliosis in patients over age 50 years may be warranted.

Congenital stenosis of lumbar spinal canal: comparison of results of surgical treatment for this and other causes of lumbar syndrome

The operative results in 37 consecutive patients suffering from developmental stenosis of the lumbar spinal canal, compared with those in spondylosis and disc herniations, are discussed. The diagnostic certainty of stenosis, suspected on the bases of clinical and radiographic data, is reached only at the operating table. To judge the usefulness of the operation we have considered not only the patients' verdicts, but also the improvements in neurological signs and the appearance of new deficits. Satisfactory results are around 80%, slightly less good with stenosis than with the other causes of lumbar syndrome. Radiographic study with contrast medium is mandatory. Dimer-X has been used with very clear radiographic findings and very few complications. Operating technique is also described: a wide laminectomy with facetectomy is advised. The great importance of early physiotherapy is emphasized.