Post-surgical outcome and recurrence rates in thoracolumbar arachnoid diverticula undergoing durotomy alone or alongside a modified technique of subdural shunt-placement in dogs.

Abstract

OBJECTIVE: The aims of this study were two-fold. First, to describe a modified technique of subdural shunt (SDS) placement for canine thoracolumbar arachnoid diverticula (TL-AD). Second, to compare outcome and recurrence of dogs following durotomy and debridement of meningeal attachments alone or in combination with SDS. ANIMALS: A total of 27 surgically managed TL-AD affected dogs. STUDY DESIGN: Retrospective non-randomized descriptive case series. METHODS: Magnetic resonance imaging (MRI) TL-AD diagnosed dogs undergoing surgery, with 4-8 weeks postoperative recheck and follow-up time of >6 months. Two groups were compared: a control group, where durotomy and debridement of subdural adhesions alone was performed; a shunting group (SG) where SDS was utilized. The surgical technique was adapted from Meren et al., differing in access (hemilaminectomy), incision shape (longitudinal) and no suturing of the SDS or dura. RESULTS: A total of 12 dogs were included in the control group and 14 in the SG. One case, excluded, developed suspected postoperative surgical infection that resolved when the SDS was removed. Immediate postoperative and short-term outcome was not significantly different between groups. In the SG, long-term outcome was significantly better with dogs having improved neurologically (85.7% vs. 41.7%), and the rate of recurrence was lower (14.3% vs. 41.7%) although this last difference was not statistically significant (p = .19). Recurrence occurred at a median of 36 months from surgery (9-62), 5/7 recurrent cases were Pugs. CONCLUSION: The adapted technique was successful in addressing TL-AD associated neurological signs in the long-term, as well as reducing recurrence of TL-AD. CLINICAL SIGNIFICANCE: Shunt-placement appears to have a positive role in outcome and possibly recurrence prevention in cases of TL-AD.