Lumbar nerve root compression resulting from extrusion of intervertebral disc material after prophylactic disc fenestration.

A 5-year-old male neutered miniature dachshund presented with a 24-hour history of nonambulatory pelvic limb paraparesis. The dog was diagnosed with grade III myelopathy, Th3-L3 neurolocalisation. Computed tomography (CT) was consistent with intervertebral disc extrusion between the second and third lumbar vertebrae (L2/3) on the left side. Left-sided hemilaminectomy was performed to remove the compressive intervertebral disc material. Intervertebral disc fenestration was performed at L2/3, prophylactic intervertebral disc fenestration was also performed at L3/4. After surgery, persistent spinal hyperpathia and kyphosis was observed, with worsening of spinal hyperpathia 48 h postoperative. Repeat CT performed 4 days after index surgery revealed laterally extruded intervertebral disc material from the L3/4 fenestration site causing compression of the left L3 nerve root. A second surgery was performed and the extraforaminal extruded intervertebral disc material at L3/4 compressing the L3 nerve root was removed. Resolution of spinal hyperpathia and kyphosis was noted after the second surgery. To the author's knowledge, this is the first report of prophylactic disc fenestration causing nerve root compression necessitating repeat surgery.