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EQUINE VETERINARY EDUCATION
Equine vet. Educ. (2020) 32 (8) 408-410 doi: 10.1111/eve.13066
Clinical Commentary Is a standardised approach to colopexy justified?
M. C. Mudge* and A. K. Gardner Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA *Corresponding author email:
mudge.3@osu.edu
Keywords: horse; colopexy; colon volvulus; dehiscence
Summary Equine colopexy techniques vary according to surgeon preference and there is no clear evidence of the superiority of any one technique. Complications secondary to colopexy are varied, but dehiscence of the colopexy site is rare, with less than 1% of horses reported to have a repeat large colon volvulus after dehiscence of the colopexy. Considerations of how and when to perform a surgical fixation of the colon to the body wall include position of the colon, length of the colopexy, and suture material and pattern. Little evidence exists regarding best practice outside of experimental studies and retrospective studies of Thoroughbred broodmares. Therefore, more work must be done to standardise a colopexy technique to apply to a broad spectrum of horses suffering from large colon volvulus and displacement.
Several methods of colopexy have been described in the literature, including incorporation of the lateral free band of the colon in the ventral midline or left paramedian celiotomy closure, and left paramedian colopexy not incorporated into the celiotomy incision. Complications arising directly from colopexy include catastrophic rupture of the colon, enterocutaneous fistula, dehiscence of the colopexy without accompanying rupture of colon, and incisional hernia. In their recent publication, Hall and Rodgerson (2020) describe the complication of colopexy dehiscence with subsequent large colon volvulus and also provide an estimate of the overall risk of this complication in a population of Thoroughbred broodmares. This complication risk appears to be quite low, with less than 1% of horses reported to have a repeat large colon volvulus after dehiscence of the colopexy. However, there may be opportunities to optimise or standardise the colopexy technique to minimise complications and promote adhesion of the colon to the body wall. Hall and Rodgerson point out the likely factors that may contribute to colopexy dehiscence, including insufficient incorporation of the body wall, shallow suture bites of lateral band of the ventral colon, intestinal compromise and excessive weight of the colon. Whether to perform a colopexy and how to perform a colopexy have typically been questions of surgeon’s preference within a framework of common-sense guidelines. There are several technical and biomechanical factors to
consider if a ‘standard’ colopexy technique were to be promoted. For example, does the position of the colopexy matter? Does the length of colopexy matter? Is the choice of suture material or suture pattern important? Based on the available literature, the post-volvulus broodmare has been the most likely candidate for colopexy; however, there may also be considerations specific to the sport horse when
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decision-making after surgical correction of a large colon volvulus or displacement. After some initial poor outcomes with experimental
colopexy, there have been a number of successful techniques reported. Hance and Embertson (1992) described a technique of colopexy of both the right and left ventral colons to right and left body walls, respectively. This technique involved elevation of the body wall with suture placement at an angle to the internal rectus fibres to help prevent suture pullout. They reported a 4.5% rate of colon rupture (2/44) and a 6.8% rate of colopexy dehiscence (3/44), with two horses having recurrence of large colon volvulus or displacement. The authors described a modification of the colopexy technique, in which they abandoned the right colopexy and incorporated the external and internal rectus fascia in the left colopexy. The authors stated that the ‘modifications to the colopexy technique used on mares subsequent to this study have seemingly prevented dehiscence of a colopexy site’ (Hance and Embertson 1992). The left paramedian colopexy was recently described in a larger number of cases, with the technique of making an initial left paramedian celiotomy approach and incorporating the lateral free band of the ventral colon in part of the closure of the celiotomy (Broyles et al. 2018). There were no instances of colopexy dehiscence specifically described in any of the 156 Thoroughbred broodmares in this retrospective report, although they reported recurrence of large colon volvulus or displacement in 1.2% of cases and recurrent colic in 17%. Incorporation of the lateral free band of the ventral colon
in the ventral midline celiotomy closure was initially reported by Hunt and Spirito (1995), and this same technique was used in the cases reported by Hall and Rodgerson (2020). The position (midline vs. left paramedian) and length (10 cm vs. 20 cm) of the colopexy differ, and although the outcomes appear to be positive with either technique, the biomechanics of the position and length of the colopexy are unknown. Experimental colopexy constructs demonstrated that manual creation of a twist at the base of the colon was possible with a short colonic adhesion (8 cm) but not possible with a long adhesion (35 cm) (Markel et al. 1988a). Despite this experimental evidence, there have not been clinical cases of large colon volvulus at the base reported with an intact, short (10–15 cm) colopexy. The authors of the accompanying case series point out
potential disadvantages of incorporating the colopexy in the ventral midline celiotomy closure. Weakness in the closure could lead to incisional hernia or incisional dehiscence. However, the incision in the body wall may promote adhesion at the colopexy site, much in the way that the incisional gastropexy technique in dogs has been successful. The canine gastropexy technique involves an incision in the
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