Patients with Bertolotti's syndrome have characteristic lumbosacral anomalies 
and often have severe sciatica. We describe a patient with this syndrome in whom 
standard decompression of the affected nerve root failed, but endoscopic 
lumbosacral extraforaminal decompression relieved the symptoms. We suggest that 
the intractable sciatica in this syndrome could arise from impingement of the 
nerve root extraforaminally by compression caused by the enlarged transverse 
process.