Thoracic spinal stenosis associated with renal osteodystrophy. Diagnosis based on magnetic resonance imaging and computed tomography

Diffuse Spinal Hyperostosis Causing Severe Spinal Stenosis and Thoracic Myelopathy

Introduction

Spinal stenosis has a wide range of causes including disc herniation, facet hypertrophy, degenerative spondylosis, facet cyst, ossification of the ligamentum flavum (OLF) and ossification of the posterior longitudinal ligament (OPLL). We present three cases of diffuse spinal hyperostosis causing severe spinal stenosis and myelopathy, which demonstrate a unique association between obesity and a novel syndrome of hyperostosis.

Case Presentation

This report describes 3 morbidly obese patients with diffuse spinal hyperostosis causing critical thoracic stenosis. Their presenting complaints focus on lower extremity weakness and the CT/MRI imaging is striking for diffuse hyper-ossification at thoracic levels. Two patients were subsequently managed with spinal decompression, and one patient was managed non-operatively.

Discussion

Metabolic changes associated with obesity may result in diffuse hyperostosis with ligament ossification and spinal stenosis. Pre-operative imaging is essential to identify the degree of ossification and potential dural involvement as this may complicate management.

Renal osteodystrophy: neurosurgical considerations and challenges

BACKGROUND

Dialysis-associated destructive spondyloarthropathy (DSA) is the major bony complication of end-stage renal disease, most commonly found in the lower cervical region. The risk factors for developing dialysis-associated DSA include duration of hemodialysis and patient age. Patients with DSA have a higher incidence of osteoporosis and poor bone mineral density, which may place them at greater risk of atraumatic fractures, instrumentation failure, and neurologic compromise.

METHODS

We describe a case of cervical radiculopathy due to dialysis-associated DSA atraumatic vertebral body fractures with a postoperative course that was complicated by instrumentation failure. We reviewed the literature regarding all 138 published cases, presenting the complications, surgical treatment options, and outcomes.

RESULTS

A 44-year-old dialysis-dependent man presented with acute neck pain, radiculopathy, and weakness due to atraumatic fracture of C5 and C6 vertebral bodies. He underwent anterior C5 and C6 corpectomies, reconstruction with mesh cage and plate, and supplemental posterior instrumentation (C4-T1). Six weeks later, a computed tomography scan revealed anterior translation across the instrumented area with failure of the posterior instrumentation. He subsequently underwent traction, revision reinstrumentation from C2 to T5, and placement of external halo ring/jacket for 6 months. At 18 months later, he remains ambulatory without evidence of construct failure.

CONCLUSIONS

Patients with renal osteodystrophy present a challenge for the spine surgeon due to compromised bone density. Hardware failure at the bone-construct interface is common in these patients, with revision surgery needed in 22% of published cases. Longer constructs with circumferential instrumentation and halo immobilization may minimize the risk of pseudoarthrosis and construct pull-out.

Acute neurologic deterioration after surgical treatment for thoracic spinal stenosis

Spondylotic changes in the thoracic spine resulting in a myelopathic syndrome is a rare condition. Surgical treatment consists of removal of the hypertrophied ligaments, facet joints and laminae (laminectomy). In this report, we review our experience in treating 12 cases of thoracic spinal stenosis (TSS). From 1989-1998, we identified 12 surgical cases treated by the Department of Neurosurgery at Temple University Hospital. For this report, we reviewed both inpatient and outpatient records and radiographic studies. We also reviewed the world's literature regarding this entity. After reviewing our own cases of TSS and the world's literature, we identified a higher than expected incidence of acute neurologic deterioration (AND) after surgical treatment of TSS (14.5%). This incidence is compared to an expected incidence of AND (0-5.5%) after laminectomy for cervical spinal stenosis (CSS). The seemingly higher incidence of AND after surgical treatment of TSS has implications for discussion of risks with patients undergoing surgical treatment.

Surgical treatment of thoracic spinal stenosis: a 2- to 9-year follow-up

STUDY DESIGN

A retrospective investigation of the results of operative treatment of patients with symptomatic thoracic spinal stenosis.

OBJECTIVES

To establish the effectiveness and define the limitations of surgical treatment for stenosis of the thoracic spinal canal.

SUMMARY OF BACKGROUND DATA

In contrast to cervical and lumbar stenosis, symptomatic narrowing of the thoracic spinal canal is rarely encountered. Although the treatment of thoracic stenosis has been described in multiple case reports and in several small series with minimal follow-up evaluation, there are few studies of patients treated surgically for this condition with follow-up evaluation beyond 2 years.

METHODS

Twelve patients who underwent operative decompression for symptomatic stenosis of the lower thoracic spine were followed up for an average period of 62.4 months. Surgery was performed on the thoracic spine alone in four cases and on the combined thoracolumbar spine in eight. Factors that were investigated included pain severity, lower extremity motor function, ambulatory status, and postoperative complications.

RESULTS

The level of pain after surgery was decreased in eight patients and unchanged in four patients. Of the 10 patients with a motor deficit before surgery, eight had improvement of muscle function. Of the 11 patients with a gait disturbance before surgery, ambulatory status was improved in seven, unchanged in two, and worse in two. One patient lost neural function secondary to surgical intervention. There were five cases in which the early result subsequently deteriorated because of recurrent stenosis, spinal deformity/instability, or both.

CONCLUSIONS

Thoracic stenosis can occur in isolation or, more commonly, in association with lumbar stenosis. Ideally, operative treatment should address all stenotic segments and directly decompress the primary anatomic abnormalities causing neural element compression. Although satisfactory short-term results can be expected, deterioration of the early outcome because of the potential for recurrent stenosis and deformity/instability at the thoracolumbar junction can sometimes be seen with longer follow-up evaluation periods.