Shunt tube placement for amelioration of cerebrospinal fluid flow obstruction caused by spinal cord subarachnoid fibrosis in dogs.

OBJECTIVE: To describe a novel technique for ameliorating cerebrospinal fluid flow obstruction secondary to pia-arachnoid fibrosis in dogs and report outcome. STUDY DESIGN: Descriptive report and retrospective case series. ANIMALS: Dogs with cerebrospinal fluid (CSF) flow obstruction (n = 7). METHODS: Medical records were searched for dogs that had a subarachnoid-subarachnoid shunt placed for treatment of CSF flow obstruction. Data collected included age, sex, breed, clinical signs and duration of signs prior to examination, neurologic status and localization prior to surgery, pre-surgical diagnostics, surgical technique, histopathology, postoperative neurologic examination, time to discharge from hospital, and outcome. RESULTS: All dogs were diagnosed at surgery with a fibrotic adhesion between the arachnoid and pia mater. A subarachnoid shunting tube was implanted to allow CSF flow across the lesion site. Five dogs showed improvement of clinical signs, 3 of which showed complete recovery and 2 of which showed improvement without resolution of all clinical signs. Two dogs showed no change at 7 and 24 months postoperatively. CONCLUSION: Bridging a region of pia-arachnoid fibrosis with a tube placed in the subarachnoid space can ameliorate or prevent progression of associated clinical signs.

Indirect imaging of the canine optic nerve, using metrizamide (optic thecography).

Between the optic nerve and its sheath is a small, CSF-filled space that communicates with the subarachnoid space of the brain. A technique for the radiographic opacification of the optic nerve subarachnoid space following the intrathecal injection of metrizamide was investigated in 8 dogs. The technique enabled indirect visualization of the optic nerves from the optic chiasm to the eyeball and of structures within the subarachnoid basal cisterns of the brain, including the optic chiasm, hypophysis, and blood vessels of the cerebral arterial circle. Displacement and obstruction of the optic nerve subarachnoid space were demonstrated after surgically creating optic nerve lesions to simulate orbital tumors and trauma. The technique was found to be safe, effective, and advantageous over other techniques currently available for the visualization of these structures.