Acute Cauda Equina Syndrome Following Microendoscopic Decompressive laminotomy

Microendoscopic decompressive laminotomy (MEDL) is a newly developed minimally invasive surgical procedure for the treatment of lumbar spinal stenosis (LSS). It is considered as effective as traditional open laminectomy for decompressing the neural stenosis, while preserving the pre-operative stability. Serious neurological complications of MEDL are seldom reported. We report a rare case of acute cauda equina syndrome following MEDL. A 53 year-old woman received MEDL for severe LSS at level L4-5. Bilateral decompression via unilateral approach was attempted but only unilateral decompression was actually performed due to technical difficulty. No dura or nerve root injury was noted during the procedure. The post-operative course was initially uneventful but she experienced slowly progressive sensory impairment on the contralateral lower limb and sphincter dysfunction after the second post-operative day. We performed wide laminectomy on the fifth post-operative day and no neural tissue injury was identified. At 6-month follow-up, the sensory impairment as well as bladder and bowel incontinence remained unimproved. Although MEDL is considered as a safe and effective procedure, severe neurological complications can occur without gross neural tissue injury. The possible causes may be attributed to inadequate decompression combined with post-operative edema of the neural tissue. We suggest bilateral approach or conversion to open surgery for cases with severe stenosis.