Fibrous adhesive entrapment of lumbosacral nerve roots as a cause of sciatica.

STUDY
DESIGN: Report of seven patients with fibrous adhesive entrapment of lumbosacral nerve roots as a cause of sciatica, whose radiographic findings were negative and who experienced relief from sciatica immediately after the entrapment was released.
OBJECTIVES: To describe a new clinical entity of fibrous adhesive entrapment of lumbosacral nerve roots with negative radiographic findings.
SETTING: Orthopaedic department, Japan.
METHODS: Clinical evaluation and post-operative outcome in seven patients with entrapment of lumbosacral nerve roots because of fibrous adhesion confirmed intraoperatively.
RESULTS: Radiographic examinations by magnetic resonance imaging (MRI), myelography, and computed tomographic (CT) myelography demonstrated neither disc herniations nor spinal stenosis in all seven patients, and differential nerve root block was effective for relieving sciatica and low back pain. We confirmed, intraoperatively, entrapment of the nerve root by fibrous adhesion, and all seven patients were relieved from sciatica and low back pain postoperatively.
CONCLUSION: This study presented seven patients with sciatica caused by fibrous adhesive entrapment of lumbosacral nerve roots who underwent decompression and release of fibrous adhesion. Radiographic examinations, such as MRI, myelography and CT myelography, showed no compressive shadows and also differential nerve root block was effective for its diagnosis. This study seems to be the first report of patients with entrapment of lumbosacral nerve roots caused by fibrous adhesion, whose radiographic findings were negative.