Extraforaminal entrapment of the fifth lumbar spinal nerve by XXXX of the lumbosacral spine: anatomic study and a report of four cases.

@entity1 @entity5040 @entity2850 @entity51 @entity158 @entity614
STUDY DESIGN: An anatomic study of the associations between the fifth lumbar spinal nerve (L5 spinal nerve) and a lumbosacral tunnel, consisting of the fifth lumbar vertebral body (L5 vertebral body), the lumbosacral ligament, and sacral ala, and clinical case reports of four @entity1 with @entity614 secondary to entrapment of the L5 spinal nerve in the lumbosacral tunnel. OBJECTIVES: To delineate the anatomic, clinical, and radiologic features and surgical outcome of @entity1 with entrapment of the L5 spinal nerve in the lumbosacral tunnel. SUMMARY OF BACKGROUND DATA: Although several cadaveric studies on a lumbosacral tunnel as a possible cause of @entity614 have been reported, few studies had focused on @entity5040 of the L5-S1 vertebral bodies as the major component of this @entity2850 , and clinical reports on @entity1 with this disease have been rare. METHODS: Lumbosacral spines from 29 geriatric cadavers were examined with special attention to the associations between @entity5040 of the L5-S1 vertebral bodies and the L5 spinal nerve. Four @entity1 with a diagnosis of the entrapment of the L5 spinal nerve by @entity5040 at the lumbosacral tunnel were treated surgically, and their clinical manifestations and surgical results were reviewed retrospectively. RESULTS: The anatomic study demonstrated @entity5040 of the L5-S1 vertebral bodies in seven of the 29 cadavers. Entrapment of the L5 spinal nerve in the lumbosacral tunnel was observed in six of the seven cadavers with @entity5040 but in only one of the 22 cadavers without such @entity5040 (P < 0.05, chi2 test). All four @entity1 had @entity51 in the L5 nerve root distribution. MRI and myelography showed no abnormal findings in the spinal canal, but CAT scans demonstrated prominent @entity5040 on the lateral margins of L5-S1 vertebral bodies in all four. Selective L5 nerve block completely relieved all @entity1 of @entity158 but only temporarily. Three @entity1 were treated via a posterior approach by resecting the sacral ala along the L5 spinal nerve, and the other @entity1 was treated by laparoscopic anterior resection of the @entity5040 . @entity158 relief was obtained in the four @entity1 immediately after surgery, but one @entity1 experienced recurrence of @entity158 1 year after the first surgery and was successfully treated by additional posterior decompression and fusion. CONCLUSIONS: Extraforaminal entrapment of L5 spinal nerve in the lumbosacral tunnel can cause @entity614 , and @entity5040 of L5-S1 vertebral bodies are a major cause of the entrapment.
