to evaluate biomaterials and techniques for use in human surgery. Several studies comparing suture materials in the rabbit urogenital tract have been performed. Comparison of polyglactin 910, polyethylene, and nylon in rabbit uteri showed that polyglactin 910 had a lower inflammation score at 24 days, and 80% of samples were absorbed by 80 days with little residual inflammation. The nonabsorbable sutures were present at 80 days and caused a persistent inflammatory response (Gomel et al. 1980). A similar study comparing polyglactin 910, polyglycolic acid, polypropylene, nylon, and chromic gut in rabbit uterine tissue found that polyglactin 910 had the lowest short‐term (16 days) and long‐term (42 days) tissue reaction. Like other studies, the nonabsorbable sutures remained in the tissues and caused a persistent inflammatory response (Beauchamp et al. 1988). Another study showed that there was no difference in histologic reaction or pregnancy rates between polyglactin 910 and polypropylene in microsurgical anastomoses in rabbit oviducts (Scheidel et al. 1986). Comparison of chromic gut, polyglactin 910, polydioxanone, and polyglyconate in rabbit pyeloureterotomies show that chromic gut caused the most severe inflammatory reaction. The reactions of the synthetic absorbable sutures were similar, but there was persistence of suture in 50% and 100% of pyeloureterotomies closed with polydioxanone and polyglyconate 12 weeks following implantation (Wainstein et al. 1997).
A study comparing gut, chromic gut, polyglactin 910, and polypropylene in rabbit bladder tissue found that the gut and chromic gut had the highest inflammation scores followed by polyglactin 910 and polypropylene. Fifteen weeks following implantation, the gut sutures and polyglactin 910 were almost completely absorbed with little residual inflammation compared to polypropylene (Hanke et al. 1994). Another study evaluating suture material in rabbit bladders compared chromic gut, polydioxanone, and polypropylene. Bladders were evaluated for calculi at 15, 30, 60, and 90 days and calculi formed on all sutures. The persistence of the calculi was dependent on the longevity of the suture material (Morris et al. 1986).
The studies performed in rodents and rabbits show that in most cases, chromic gut is more reactive than synthetic absorbable sutures. Nonabsorbable suture materials tend to cause chronic inflammatory responses where absorbable suture materials leave little residual inflammation after they are broken down. These studies and others on domestic species demonstrate the importance of choosing suture material that will retain tensile strength only long enough for the tissues to heal. Any suture that remains after the tissue has healed can lead to granulomas, calculi, or possibly malignant transformation of the tissues.
Ferrets
A single case report exists pertaining to suture material use in ferrets (Petterino et al. 2010). An intraabdominal malignant mesenchymoma was removed from a 6 year old spayed female ferret. The mass originated at the area of the previous ovariectomy performed five years previously. Histopathologic examination showed a mixed population of neoplastic cells, and nonabsorbable suture material was admixed with the neoplastic tissue. A chronic inflammatory reaction to the suture may have played a role in tumor development. Unfortunately, the type of suture implanted was not determined.
Birds
Despite their popularity and the increasing frequency for which veterinary care is pursued (Shepherd 2008), only a single study exists evaluating suture materials in birds. In this study, histologic reaction to five suture materials (chromic gut, polydioxanone, polyglactin 910, monofilament nylon, and stainless steel) was evaluated in the body wall of rock doves (Columba livia) over a period of 120 days (Bennett et al. 1997). Polyglactin 910 caused an early and intense inflammatory response and had higher inflammation scores than all other suture types. Chromic gut also caused an early and sustained inflammatory response. Initially, polydioxanone caused minimal reaction, but there was an increase in inflammation between 60 and 90 days. Steel and monofilament nylon stimulated minimal inflammatory reaction, but lead to hematomas, seromas, and caseogranulomas. Based on this study, polydioxanone is the optimal suture for closing the body wall due to the minimal inflammatory response and lack of complications seen with stiff nonabsorbable sutures. Interestingly, the lead author of that study prefers polyglactin 910 for skin closure in birds because the soft suture is less irritating (R. Avery Bennett, personal communication).
Reptiles and Amphibians
A few studies have evaluated sutures in reptiles and a single study evaluated suture materials in amphibians (Tuttle et al. 2006). Five suture materials (silk, monofilament nylon, polydioxanone, polyglactin 910, and chromic gut) were evaluated in African clawed frogs (Xenopus laevis) to determine which suture material elicited the fewest inflammatory changes in amphibian skin over 14 days. All sutures caused significantly more inflammation than a stab incision that was left to heal by second intention. Chromic gut and silk caused significantly more inflammation than all other sutures and 67% of incisions closed with silk sutures dehisced. Polydioxanone and polyglactin 910 caused significantly more inflammation than monofilament nylon. There were no significant differences in scores between 7 and 14 days. Based on these results, chromic gut and silk are not recommended and monofilament nylon may be the most appropriate suture in amphibian skin.
Using absorbable suture may result in premature suture material dissolution and wound dehiscence in aquatic amphibians (Baitchman and Herman 2015). Alternatively, cyanoacrylate tissue adhesive has been used for skin closure both in terrestrial and aquatic amphibians because it is waterproof. Studies are needed to compare cutaneous healing following suture or cyanoacrylate tissue adhesive application in amphibians. The use of polydioxanone has been reported anecdotally for amphibian internal organs (Green 2010; Norton et al. 2014).
Early studies on wound healing in reptiles compared sutured and unsutured wounds in garter snakes (Smith et al. 1988). Paired 1 cm incisions were either sutured with 5‐0 polypropylene or left to heal by second intention. They showed that unsutured wounds had significantly less disruption of scale pattern and overlap of wound margins, and less‐intense inflammatory infiltrates.
Four different suture materials (chromic gut, polyglyconate, polyglactin 910, and poliglecaprone 25) were evaluated histologically 7 days following laparoscopic sex determination (Govett et al. 2004). Results indicate that poliglecaprone 25 and polyglyconate caused the least tissue reaction of the four suture types examined. These synthetic monofilament absorbable suture materials caused significantly less crust formation and panniculus inflammation than chromic gut and polyglactin 910.
A study evaluated eight suture materials (polydioxanone, polydioxanone/triclosan, poliglecaprone 25, poliglecaprone 25/triclosan, polyglactin 910, chromic gut, monofilament nylon, and surgical steel) and cyanoacrylate tissue adhesive in hatchling ball pythons over a period of 90 days (McFadden et al. 2011). Samples were evaluated histologically at 3, 7, 14, 30, 60, and 90 days following implantation. Over all time points, all suture types caused significantly more inflammation compared to the negative control. Cyanoacrylate tissue adhesive did not cause significantly more inflammation than the negative control at any time point suggesting that small superficial skin incisions or lacerations can be closed with cyanoacrylate tissue adhesive. All suture materials caused chronic inflammatory responses that were significantly higher than the negative control 90 days following suture implantation. No sutures were completely absorbed by the end of the study period suggesting that absorption times are prolonged compared to mammals. Despite previous reports that reptiles are unable to breakdown chromic gut (Jacobson et al. 1985; Bennett 1989), there was histologic evidence of fragmentation of these sutures. Interestingly, there was also evidence that prolonged absorption may lead to suture extrusion prior to complete absorption.
Based on these studies, monofilament synthetic rapidly absorbed suture material such as poliglecaprone 25 should be used in reptiles. Unfortunately, glycomer 631 and polyglytone 6211 have not been compared to poliglecaprone 25 in reptiles.
Fish
Of all exotic species commonly
