Study Design. This case study is designed to report the previously unr
eported specific complication of acute cauda equina compression after
decompression surgery for spinal stenosis. Objectives. To inform other
s of the possibility of such a complication; to suggest a possible mec
hanism for this situation, namely hourglass constriction of the cauda
causing ischemia to distal nerve roots; and to suggest a management pl
an-immediate magnetic resonance imaging to identify the problem and re
turn to the operating room for further decompression-which was success
ful in this case. Summary of Background Data. Previous reports of caus
es of paraparesis or paraplegia after surgery are listed, and previous
theories on the etiology of acute cauda compression are discussed. Me
thods. The clinical findings of spinal stenosis in a 32-year-old man a
re presented, and subsequent details of the surgery, complications aft
er surgery, investigation, and future surgery, including magnetic reso
nance imaging scans before and after surgery, are provided. Results. T
he result in this case was a patient free of symptoms. Conclusions. In
complete decompression in surgery for spinal stenosis can result in ac
ute cauda equina compression. In these circumstances, magnetic resonan
ce imaging can reveal the cause, and in this case, immediate surgery w
as successful in relieving the symptoms and signs.