Outcomes of dogs with progressive myelomalacia treated with hemilaminectomy or with extensive hemilaminectomy and durotomy

Abstract

Objective: To evaluate the ability of extensive hemilaminectomy and durotomy (EHLD) to control progressive myelomalacia (PMM) in dogs. Study design: Retrospective clinical study. Animals: Twenty-eight client owned dogs that underwent EHLD (n = 10) or HL alone (n = 18). Methods: After diagnosis by MRI, dogs were immediately treated with HL alone or EHLD at the site of intramedullary hyperintensity on T2-weighted (T2W)-MRI. Medical records were retrospectively reviewed. Follow-up data were collected via telephone interviews with the referring veterinarian and a standardized questionnaire. Postoperative survival outcome between groups was compared (log-rank test) by using Cox's proportional hazard analysis with baseline characteristics entered as covariates. Results: The survival rate was higher in the EHLD group (P =.03) compared with the HL-alone group. Eleven of 18 dogs treated with HL survived, while seven of 18 dogs died (median, 5 days after surgery). In the EHLD group, 10 of 10 dogs survived postoperatively. Baseline characteristics were not associated with postoperative survival outcomes. According to multivariate analysis, EHLD was the independent factor associated with an increase in survival rate (P =.0002). Conclusion: EHLD durotomy at the intramedullary hyperintense region on T2W-MRI improved the survival rate of dogs with PMM compared with dogs treated with standard HL. Clinical significance: This study provides evidence that supports treatment with EHLD in dogs with PMM. Additional prospective studies are required.