Epidural lipomatosis and congenital small spinal canal in spinal anaesthesia: a case report and review of the literature.

INTRODUCTION: Complications after lumbar anaesthesia and epidural blood patch have been described in patients with congenital small spinal canal and increased epidural fat or epidural lipomatosis. These conditions, whether occurring separately or in combination, require magnetic resonance imaging for diagnosis and grading, but their clinical significance is still unclear. CASE PRESENTATION: A 35-year-old Caucasian woman who was undergoing a Caesarean section developed a longstanding L4-L5 unilateral neuropathy after the administration of spinal anaesthesia. There were several attempts to correctly position the needle, one of which resulted in paraesthesia. A magnetic resonance image revealed that the patient's bony spinal canal was congenitally small and had excess epidural fat. The cross-sectional area of the dural sac was then reduced, which left practically no free cerebrospinal fluid space. CONCLUSION: The combination of epidural lipomatosis of varying degrees and congenital small spinal canal has not been previously discussed with spinal anaesthesia. Due to the low cerebrospinal fluid content of the small dural sac, the cauda equina becomes a firm system with a very limited possibility for the nerve roots to move away from the puncture needle when it is inserted into the dural sac. This constitutes risks of technical difficulties and neuropathies with spinal anaesthesia.