Cauda equina syndrome following decompression for spinal stenosis.

Cauda equina syndrome following decompression for spinal stenosis appears to occur more commonly than the literature suggests. A large series of spinal stenosis decompressions was reviewed. Based on these findings, a theory is put forth as to the cause of this complication. One hundred seventy-five cases of decompression for spinal stenosis done over a 2.5-year period were reviewed. Follow-up was 1year to 2 years and 4 months. There were 14 cases of postoperative urinary retention, for an incidence of 8%. Of those, five were ultimately diagnosed with cauda equina syndrome, for an incidence of 2.8%. Of the nine cases that were not diagnosed as cauda equina syndrome, five resolved spontaneously over 2 to 6 weeks. The remaining four were diagnosed as having mechanical urinary problems (e.g., prostate or prolapsed bladder) that required surgical treatment. Anal sphincter monitoring at the time of surgery was not predictive in those patients who developed cauda equina syndrome. All patients who developed cauda equina syndrome improved over 3 to 9 months, but none completely resolved. Three cases underwent further decompression with no apparent improvement. Cauda equina syndrome occurs in 2.8% of decompressions for spinal stenosis.