Laparoscopic Closure of the Nephrosplenic Space in Horses with Nephrosplenic Colonic Entrapment: Factors Associated with Survival and Colic Recurrence.

OBJECTIVES 1) To identify factors associated with short-term survival and time to death after hospital discharge in horses with nephrosplenic entrapment (NSE). 2) To compare the frequency of recurrent colic episodes in horses with and without laparoscopic closure of the nephrosplenic space. STUDY DESIGN Historical cohort with a nested case control. ANIMALS Client-owned horses. METHODS Medical records of horses treated for NSE from January 1, 2002 to June 1, 2014 were reviewed. Data collected included signalment, physical examination parameters, laboratory results, diagnostic findings, and treatments. Factors associated with short-term survival to discharge were analyzed with a multivariable logistic regression model and time to death after hospital discharge was analyzed with a Cox proportional hazards model. RESULTS During the study period, 211 horses had 231 NSE events and 192/211 (91%) horses survived to discharge. A positive difference in packed cell volume (PCV at admission - PCV after treatment) was associated with reduced odds of nonsurvival with each increment (OR: 0.899, 95% CI 0.816-0.991, P=.03) while the presence of concurrent alimentary lesions (OR: 8.47, 95% CI 1.42-50.4, P=.02) were significantly associated with increased odds of nonsurvival in the short term. Of 156 horses that survived to discharge for which follow-up was available, 152 (97%) were alive for ≥1 year. Increasing age (incremental years) at hospital admission was significantly associated with death after discharge (hazard ratio 1.078, 95% CI 1.002-1.16, P=.049). Recurrence of NSE was documented in 49/211 (23%) horses. The overall change in colic score indicated a reduction in colic in horses following laparoscopic closure of the nephrosplenic space compared with horses that did not have closure of the nephrosplenic space (P<0.001). CONCLUSION An increase in PCV from admission to after treatment and concurrent abdominal lesions were associated with increased odds of nonsurvival to discharge in horses with NSE. Horses that underwent laparoscopic closure had reduced colic episodes compared with horses without laparoscopic closure.