Bursting strength of surgeon's and self‐locking knots for closure of ventral midline celiotomy in horses

Abstract

Objective To compare the bursting strength and failure mode of ventral midline celiotomy closed with a simple continuous suture pattern with 1 of 2 knot combinations, a novel self‐locking knot combination of a forwarder start with an Aberdeen end knot (F‐A) and a traditional combination of a surgeon's start with a surgeon's end knot (S‐S). Study design Ex vivo experimental. Sample population Equine cadavers (n = 14). Methods A 20‐cm ventral midline celiotomy was created in 14 equine cadavers. Horses were assigned to celiotomy closure with an F‐A or S‐S knot combination. Prior to closure, a 200‐L inflatable bladder was placed in the abdomen and then insufflated until failure of the celiotomy closure. The horses’ signalment, weight, breed, and age, as well as knot combination type, mode of failure, closure time, and bursting strength (mm Hg) were recorded. Results The median bursting strength was significantly greater when incisions were closed with the F‐A knot combination (388 mm Hg) compared with the S‐S knot combination (290 mm Hg) (P = .035). Most incisions failed along the fascia when closed with F‐A combinations and at the knot when closed with S‐S combinations. Conclusion The bursting strength of ventral midline incisions in equine cadavers was increased by an average of 25% when closed with the self‐locking F‐A knot combination. Clinical significance Closing ventral midline celiotomies with an F‐A knot combination may provide a more secure closure than the traditional S‐S knot combination. Additional in vivo investigation is required prior to recommending this closure in clinical cases.

Tensile strength and early healing of self‐locking and surgeon's knots

“…Previous in vitro and ex vivo research has provided evidence that selflocking knots are more secure with smaller weight and volume compared with surgeon's knots; however, testing was performed under single load to failure and supraphysiologic conditions. 12,[17][18][19] Location of failure for F-A segments was more common along the rectus sheath than incision consistent with normal body wall (control) when this was tested for in a single load to failure in this study. It is important to recognize that testing of incisional failure by using single load does not accurately represent incisional failure in vivo, but, to the best of the authors' knowledge, all ex vivo studies in which incisional failure in the horse has been evaluated have used single load to failure, measured as either bursting or tensile strength.…”

“…It is important to recognize that testing of incisional failure by using single load does not accurately represent incisional failure in vivo, but, to the best of the authors' knowledge, all ex vivo studies in which incisional failure in the horse has been evaluated have used single load to failure, measured as either bursting or tensile strength. 12,[24][25][26][27] The study model consisted of physiologic conditions of anesthetic recovery and 10-day postoperative healing to mimic stresses and strains applied to closures. Findings provide evidence that either knot combination results in a secure closure that withstands the biodynamic forces and loads applied during anesthetic recovery and the early postoperative period.…”

“…8,10,11 The most common mode of incisional failure of a suture line is failure of the surgical knot in ex vivo studies. [12][13][14][15] However, the body wall adjacent to the incision has been reported to be a common site of failure in clinical cases. 16 This highlights the requirement for further investigation of closure techniques in vivo to better understand the role of suture and surgical knots.…”

“…Self-locking knots have been shown to have improved strength when they have been tested in large gauge suture. 12,[17][18][19][20] The Aberdeen end knot exhibited greater relative knot security (RKS) and knot holding capacity (KHC) compared with square and surgeon's knots, requiring three to four fewer throws, with a smaller knot size when they were dry and after exposure to biological media. [17][18][19]21 The forwarder start knot had higher RKS and KHC compared with a surgeon's knot, with lower volume under similar conditions.…”

“…18,20 ex vivo comparison provided evidence of greater bursting strength after closure with the self-locking knot combination compared with surgeon's knots. 12 While these knots have been advocated for human abdominal surgery to increase knot security and relieve tension, it is unknown how this translates to the biodynamics of equine linea alba in early wound healing. 22 The study objective was to compare the biomechanical properties and healing of VMC closed with a selflocking knot combination, forwarder start and Aberdeen end (F-A), or a traditional knot combination, surgeon's start and end (S-S).…”