# Short- and Long-Term Outcomes in Horses Following Laparoscopic Nephrosplenic Space Ablation

## TL;DR

A minimally invasive surgery to prevent recurring colic in horses shows high survival and owner satisfaction over long-term follow-up.

## Contribution

This study provides long-term evidence supporting the safety and efficacy of laparoscopic nephrosplenic space ablation in horses.

## Key findings

- Most horses were discharged without complications and had high survival rates over up to nine years.
- About one-third of horses experienced colic episodes post-surgery, mostly suspected to be recurrence of LDDLC.
- High owner satisfaction and return to athletic or breeding activity were reported in the majority of cases.

## Abstract

Left dorsal displacement of the large colon is a frequent cause of colic in horses. It can recur, limiting performance and increasing costs and management demands for owners. We evaluated a minimally invasive surgical procedure that closes the space between the spleen and the left kidney to reduce the risk of the colon becoming trapped. We reviewed 48 horses treated in two Italian Veterinary Teaching Hospitals and followed them for up to nine years. Most horses were discharged without early complications, and most were still alive at the last follow-up. About one in three horses had colic episodes after discharge; most often this was suspected to be a recurrence of left dorsal displacement, and only a small proportion required abdominal surgery. Most horses returned to athletic or breeding activity, and most owners reported a positive outcome. Our results support this laparoscopic preventive procedure as a safe option that can help maintain long-term function and welfare. It can also provide reassurance to owners, although some colic episodes may still occur and require monitoring.

Left dorsal displacement of the large colon (LDDLC) is a common cause of colic in horses and it is frequently associated with recurrent episodes, with significant implications for horse management, athletic performance, and owner satisfaction. Laparoscopic nephrosplenic space (NSS) ablation is a preventive surgical technique aimed at reducing recurrence in horses with a history of medically or surgically treated LDDLC. This retrospective study evaluated 48 horses that underwent laparoscopic NSS ablation in two Italian Veterinary Teaching Hospitals between 2016 and 2024. Short-term outcomes, including immediate postoperative complications and discharge status, were assessed. Long-term follow-up data were collected via owner questionnaires, focusing on survival, recurrence of colic, post-surgical complications, return to athletic or breeding activity, and owner satisfaction. Most horses were discharged without complications (91.7%), while postoperative colic occurred in 8.3%. Kaplan–Meier estimated one-year post-discharge survival was 83.3%, and 81.3% of horses were alive at last follow-up (range 0.7 months to 8.8 years). Post-discharge complications were reported in 31.2% of horses, most commonly recurrent LDDLC. Return to preoperative athletic or breeding activity was reported in 70.8% of cases, and owner satisfaction was high (83.3%). Time-to-event analysis indicated markedly reduced survival in horses requiring laparotomy during follow-up. Bayesian logistic models suggested lower mortality and fewer post-discharge complications in horses with prior colic surgery, whereas a history of recurrent colic and laparotomy during follow-up was associated with higher mortality and complications. These results indicate that laparoscopic NSS ablation is an effective and safe procedure for long-term management of horses at risk of LDDLC, allowing a high rate of survival, functional recovery, and owner satisfaction, despite the persistence of occasional colic episodes.