A scoping review on intraoperative and postoperative surgical castration complications in domesticated equids

BACKGROUND

Castration is the most common surgical procedure in domesticated equids; surgical techniques used and perioperative management vary considerably.

OBJECTIVES

To identify and chart the current evidence on perioperative complications associated with different methods of surgical castration in domesticated equids.

STUDY DESIGN

Joanna Briggs Institute systematic scoping review.

METHOD

CAB Abstracts, Medline and Embase databases were searched using terms related to equine castration complications. Two authors independently and blindly screened publications against eligibility criteria. Data on study methods, perioperative management, surgical techniques, and perioperative complications were extracted. Surgical techniques were grouped into categories depending on technique; open, closed or half-closed, and whether the parietal tunic was open or closed at the end of surgery.

RESULTS

The search identified 1871 publications; 71 studies met the final inclusion criteria. The data reported 76 734 castrations, most of which were open or closed, with the vaginal tunic remaining open at the end of surgery. Twenty-five studies reported information regarding surgical techniques and perioperative management, allowing detailed charting and comparisons, of which analgesia and antimicrobial usage varied notably. Eighteen different complications were reported, with swelling or oedema being the most common. Evisceration was most commonly reported in draught breeds and Standardbreds, and the risk appeared low if the parietal tunic was closed at the end of surgery.

MAIN LIMITATIONS

Grey literature and studies not available in English were not included. Existing studies varied greatly in perioperative management, surgical techniques and reporting of outcomes, making evidence consolidation problematic.

CONCLUSION

A lack of consensus regarding complication definitions creates uncertainty and discrepancies between complication rates associated with different surgical techniques and perioperative management. The implementation of standardised systems for describing surgical techniques and complications is recommended for future studies. A number of studies did not follow current recommendations for perioperative analgesia and use of antimicrobials.

The effect of Traumeel LT ad us. vet. on the perioperative inflammatory response after castration of stallions: a prospective, randomized, double-blinded study

Introduction

Stallion castration is a standard procedure with a risk of post-surgical complications. Castration induces an acute phase response (APR). Serum Amyloid-A (SAA) is a well-studied major acute phase protein (APP), that has been shown to be a good marker for the development of post-surgical complications. The current gold standard for reducing the APR after castration is Flunixin-Meglumin, which is a non-steroidal anti-inflammatory drug (NSAID) inhibiting COX1/2. In contrast, Traumeel LT ad us. vet. can modulate the APR by induction of the inflammation resolution. The aim of this study was to compare the effect of Flunixin-Meglumin and Traumeel LT ad us. vet. on the acute phase response.

Material and methods

A total of 60 stallions were recruited and 54 stallions entered the study with 27 stallions in each treatment group. The stallions were treated pre- and postoperatively with either Flunixin-Meglumin (FL) or with Traumeel LT ad us. vet. (TR). Blood was taken before and 24 h, 48 h and 72 h after castration. The following main parameters were assessed: SAA, fibrinogen, iron, white blood cells, neutrophils, Interleukin1ß, and cortisol. Wound healing and pain were assessed at 8 time points.

Results

The main variable SAA was increased after surgery reaching a mean value of 122 µg/ml in the FL group and a mean SAA of 226 µg/ml in the TR group 48 h after surgery, reaching a significant difference only at the 24 h timepoint (p = 0.03). All stallions had the highest pain summary score 8 hours after surgery, with decreasing values thereafter. The pain scores were not statistically different at any time point. In the FL group five stallions developed a suture dehiscence compared to only one stallion in the TR group (p = 0.001).

Discussion

Within the limitations of this study, Traumeel LT ad us. vet. seems to have proresolving effects on the inflammation induced by surgery making it a valuable treatment to reduce the APR induced by castration. Due to its different mode of action, Traumeel LT ad us. vet. might be an alternative treatment option if gastrointestinal side effects or renal side effects of NSAIDs should be avoided. Further studies are needed combining Traumeel LT ad us. vet. and Flunixin.

GnRH Vaccine Could Suppress Serum Testosterone in Stallion Mules

Stallion mules have been used as working equids in several countries. Aggressiveness under the influence of testosterone results in the necessity for surgical castration before work training. The gonadotropin-releasing hormone (GnRH) vaccine may be an alternative method for immunocastration in mules. The objective of this study was to evaluate the effect of the GnRH vaccine on anti-GnRH antibody concentration, serum testosterone concentration, clinical adverse effects, and behavioral changes in response to receiving selected physical manipulations from humans. Twenty-five mules were separated into three groups: Control-intact, Control-castrated, and Treatment. The Treatment group was further divided according to condition (intact or unilateral cryptorchid) and age. The Treatment group received 195 µg of the GnRH vaccine intramuscularly at weeks 0, 4, and 8. The anti-GnRH antibody concentrations increased at weeks 6 and 10, and then they gradually decreased to baseline at week 24. The Treatment-intact-young group had the highest concentration of anti-GnRH antibody. The serum testosterone concentrations in the Treatment group were lower than before vaccination from weeks 6 to 14. Subcutaneous edema adjacent to the injection site was detected in the Treatment-intact group after booster vaccination. In conclusion, the mules responded to the GnRH vaccine, which could temporarily suppress testosterone for up to 14 weeks.

Lower airway ultrasonographic, endoscopic, and cytological changes in horses undergoing inhalation anesthesia with controlled ventilation for minor elective surgeries

Effects of general anesthesia with controlled ventilation on the respiratory system have had limited evaluation in horses. A prospective observational study was performed with eleven client-owned horses undergoing elective surgery. Physical examination, auscultation with a rebreathing bag, complete blood cell count, lung ultrasound imaging, tracheal endoscopy imaging and transendoscopic tracheal wash were conducted before and 24 hours after anesthesia. Lung ultrasound imaging was also repeated just after recovery. A significant increase in blood neutrophil count between pre- and post-anesthesia (P=0.004) was observed. There was an increase in ultrasonographic score of the lungs at recovery (left P=0.007, right P=0.017). The score of the dependent lung was higher than the independent lung at recovery time (P=0.026) but no difference was observed 24 hours after anesthesia. The tracheal mucus score was higher after anesthesia (P=0.001); severe local inflammation was present in several horses at the site of endotracheal tube cuff. Neutrophil count was significantly higher on tracheal wash fluid cytology after anesthesia (P=0.016), without any significant changes on bacterial load. Increased tracheal mucus score and neutrophil count in tracheal wash samples were observed after general anesthesia in healthy horses without clinical evidence of pneumonia (fever, cough). Tracheal inflammation secondary to endotracheal intubation and cuff inflation was, therefore, suspected. Elective surgery without complications can induce inflammation of the trachea and changes in ultrasound images of the lungs in healthy horses and should be considered when evaluating respiratory system after a general anesthesia.

Intratesticular Versus Intrafunicular Lidocaine to Reduce Perioperative Nociception and Immunological Response in Ponies Undergoing Field Castration

The aim of this study was to evaluate the impact of intratesticular or intrafunicular lidocaine to reduce perioperative nociception and cytokine release in ponies undergoing field castration under total intravenous anaesthesia. Before castration, one group was injected with intrafunicular (FL) lidocaine and the other received intratesticular (TL) lidocaine. All ponies were premedicated with acepromazine (0.05 mg/kg) intramuscularly. Twenty minutes after the administration of acepromazine, xylazine (1 mg/kg) and butorphanol (0.02 mg/kg) were administered intravenously. Lidocaine 2% was given 1 mL/100 kg intrafunicularly in the FL groups or 2 mL/100 kg intratesticularly on each testicular side for TL. Surgery was performed by the same team of two experienced surgeons using Serra's emasculator and an open technique was used for all ponies in order to promote postoperative drainage. In this study, we focused on the plasmatic levels of TNF-α and IL-6. The results from this study showed a significant difference in plasmatic concentrations of TNF-α and IL-6 between the two different locoregional anaesthetic protocols. Taken together, the results suggest that the intrafunicular lidocaine locoregional anaesthesia could be a useful technique in the anaesthesia protocol for field pony castration.

Development and Formative Evaluation of a Low-Fidelity Equine Castration Model for Veterinary Education

Entrustable Professional Activities (EPAs) are units of activity that early-stage professionals perform in the workplace that necessitate simultaneous integration of multiple competencies. EPA #6 requires students to perform a common surgical procedure on a stable patient, including pre-operative and post-operative management. Castration is one of the most common surgeries performed by equine primary care practitioners and is considered an "entry-level competency" for veterinary graduates entering equine private practice, however, to our knowledge there are no equine castration models available for veterinary student education. Therefore, we developed an inexpensive, low-fidelity model of equine field castration and evaluated it using a mixed-methods approach. Two different groups of students, with or without model experience, completed surveys before and after live horse castration. Students who used the model also completed model specific surveys. Videos of the students completing the model were evaluated by at least two different equine veterinary faculty using a 15-point rubric, and inter-rater reliability of the rubric was determined. After completing the model, students reflected on strengths and weaknesses of their performance. From our student survey results, we determined that student attitudes toward the model were mostly positive. Interestingly, there were several student attitudes toward the model that became significantly more favorable after live horse castration. Prior to live horse castration, there was no significant difference in confidence in model vs. no-model groups. Following live horse castration, students who used the model had higher confidence in procedure preparation and hand-ties than students who did not use the model, but they had lower scores for confidence during patient recovery. When reflecting on model castration, students most commonly cited preparation and surgical description as strengths, and ligature placement and hand-ties as weaknesses. Experts provided several suggestions to improve the model, including incorporation of emasculators and the need for better model stabilization. Our findings suggest that both students and veterinary educators feel that this low-fidelity model has educational value. Rubric performance metrics were favorable, but additional steps are needed to improve grading consistency among educators. Future research will determine whether student performance on the model is predictive of competence score during live-horse castration.

Castration Complications: A Review of Castration Techniques and How to Manage Complications

Castration is one of the most common surgical procedures performed in equine practice. Open, closed, and semiclosed techniques are described for castration of horses, and the procedure may be performed in a standing, sedated animal or in a recumbent animal under general anesthesia. Although a relatively routine procedure, complications can occur, with reported complication rates ranging from 10.2% to 60%. Most complications are mild and resolve rapidly with appropriate treatment, but more serious or life-threatening complications can also occur. A thorough knowledge of male reproductive anatomy combined with good surgical technique is imperative to help reduce the rate of complications.

Effects of Flunixin Meglumine, Firocoxib, and Meloxicam in Equines After Castration

This study is "aimed" to evaluate and compare the efficacy of flunixin meglumine (FM), firocoxib (FX), and meloxicam (MX) after castration of horses. Thirty horses were submitted to open castration and divided into three groups (n = 10) depending on the anti-inflammatory drug administered: group I (GI) (FM, 1.1 mg kg¹, IV, once a day [SID], 5 days); group II (GII) (FX, 0.1 mg kg¹, IV, SID, 5 days), and group III (GIII) (MX, 0.6 mg kg¹, IV, SID, 5 days). Clinical, behavioral, and hematological parameters and the peritoneal fluid (PF) were evaluated before (day [D] 0) and 1, 2, 3, 5, and 7 days afterward. In the postoperative, scores of limb rigidity and prepuce edema of animals of GII and GIII were greater than those of GI. Tachycardia was observed in the horses of GII and GIII and hyperthermia in GIII. An increase in the number of leukocytes, neutrophils, and monocytes without exceeding the reference values and hyperfibrinogenemia was observed in the animals of GI (D7), GII (D1-D7), and GIII (D7). There was reduction in serum protein after castration, together with an increase of this in the PF of the animals of the three groups. The PF on D0 was straw yellow and limpid, became reddish and cloudy on D1, and then gradually moved toward its normal color on the ensuing days, but without returning to normal on D7 in any of the groups. The results showed that castration triggers significant clinical and laboratory changes and that FM, FX, and MX are equally effective in controlling pain and inflammation in horses after castration; however, FM was more advantageous.

Comparison of xylazine and detomidine in combination with midazolam/ketamine for field castration in Quarter Horses

BACKGROUND

The ideal field anaesthetic protocol for castration will offer an adequate duration and depth of anaesthesia using a single injection without compromising safety or recovery quality.

OBJECTIVES

The objective of this study was to compare intravenous (IV) xylazine and detomidine as sedatives in combination with midazolam and ketamine for induction of anaesthesia in horses undergoing field castration.

STUDY DESIGN

Randomised, blinded, clinical study.

METHODS

Fifty-seven male Quarter Horses were randomly assigned to receive xylazine (group X) (1.1 mg/kg bwt) or detomidine (group D) (0.03 mg/kg bwt) as premedication with midazolam (0.05 mg/kg bwt) and ketamine (2.2 mg/kg bwt) anaesthesia. Using simple descriptive scales, quality of sedation, induction, surgical conditions and recovery were scored by blinded observers. Induction, surgery, recovery time and time from induction to standing were recorded.

RESULTS

There were a greater number of horses with lower sedation score in group D when compared with horses in group X at 5 minutes after the first dose of sedation (11.1%, 66.7% and 2.2% of horses from group D with sedation scores of 1, 2 and 3, vs 0%, 52% and 48% from group X, respectively, P = .05). A significant (P < .01) difference was found between surgical condition scores for group D (63%, 14.8%, 11.1% and 11.1% with surgery scores of 1, 2, 3 and 4, respectively) and group X (28%, 4%, 28% and 40%). Horses in Group D were less likely to require maintenance doses of ketamine (P = .05) with only 26% (7 of 27 horses) in this group requiring additional doses compared to 68% (17 of 25 horses) in group X. Recovery time in minutes (Group D: 24.74 ± 14.80, Group X: 13.08 ± 8.00; P < .01) and induction to standing time in minutes (Group D: 42.2 ± 13.8, Group X: 29.8 ± 8.2; P < .01) were significantly longer for horses in group D compared with group X.

MAIN LIMITATIONS

Multiple surgeons and multiple blinded observers.

CONCLUSIONS

Detomidine as compared with xylazine as premedication results in good quality sedation and surgical conditions and prolonged surgical plane of anaesthesia, without significant differences in induction or recovery quality.

Evaluation of three ligatures in simulated equine open castration

OBJECTIVE

To compare three surgical knots for preventing leakage from the vascular bundle during ligation in simulated equine open castrations.

STUDY DESIGN

Randomized, case-control, in vitro study.

SAMPLE POPULATION

Testes (N = 60) collected from 30 horses.

METHODS

Testes were collected from 30 horses and randomly assigned to one of three groups: group G (friction, giant knot), group T (modified transfixing knot), or group S (sliding, strangle knot; n = 20/group). The assigned knot was used to ligate the vascular bundle during open castration. The length of suture material used and the leak pressure of the testicular artery were measured and compared between groups.

RESULTS

Strangle knots consistently leaked at higher pressures (median, 735.5 mm Hg; interquartile range [IQR], 735.5-735.5) compared with giant (median, 441.3 mm Hg; IQR, 367.8-643.6) and transfixing (median, 419.2 mm Hg; IQR, 323.6-643.6; P < .0001) knots. Both the strangle (median, 5 cm; IQR, 4.5-5.5) and giant (median, 6 cm; IQR, 5.35-6.075) knots required less suture material compared with the transfixing (median, 9.2 cm; IQR, 8.425-10.38; P < .0001) knot.

CONCLUSION

The three surgical knots tested withstood pressure well above physiological levels in simulated open castrations. The strangle knot withstood higher pressure and required similar (giant) or less (transfixing) suture material than the other two knots.

CLINICAL SIGNIFICANCE

This study provides evidence to support the use of a strangle knot to ligate the vascular bundle during simulated open castrations in horses.

Managing castration complications

There are many possible approaches to ‘routine’ castration of horses with normally descended testicles and the approach utilised is generally decided by the clinician. Unfortunately, complications are relatively common after castration, ranging from rates of 10–60% of animals, therefore knowledge of their predispositions, signs and management is essential to prevent further morbidity and mortality. Reported complications include excessive swelling, haemorrhage, infection (including clostridial infections), funiculitis, peritonitis, eventration, penile trauma +/- paralysis, hydrocoele formation, continued stallion-like behaviour and anaesthetic complications. Most complications are not considered life threatening and do not require emergency treatment; the exceptions are eventration, haemorrhage, peritonitis and clostridial infections, all of which are potentially life-threatening.

Minimally invasive, compartmentalized, modified open castration technique with primary closure in equids

OBJECTIVE To describe use of a modified open castration technique with a scrotal approach and primary closure in equids. DESIGN Prospective case series. ANIMALS 38 client-owned, sexually intact male equids. PROCEDURES With owner consent, elective castration was performed with a modified open technique on patients (1 pony, 1 miniature horse, and 36 horses of other breeds) under general anesthesia. The procedure included minimal dissection into the scrotal region for removal of testes, with cremaster muscles left intact and the parietal vaginal tunic closed in place. Primary closure of surgical wounds was performed. Patients were monitored for signs of complications. Signalment, surgery-related variables, results of ultrasonographic imaging, postoperative treatments, and outcomes were recorded. Follow-up information was obtained from owners ≥ 6 months after surgery. Medical records were reviewed, and descriptive data were reported. RESULTS Median anesthesia and surgery times were 113.5 and 60 minutes, respectively. Duration of hospitalization ranged from 1 to 3 days. No intraoperative complications were observed. Postoperative complications (moderate swelling in the scrotal region) developed in 2 of 38 (5%) patients. Mild scrotal swelling (n = 5) and transient pyrexia (typically mild; 9) also occurred; no patients had signs of postoperative bleeding, infection, or colic. All equids gradually returned to exercise beginning 10 days after the procedure. Cosmetic results were considered excellent. CONCLUSIONS AND CLINICAL RELEVANCE The modified castration technique was considered simple to perform and advantageous because of the low complication rate, excellent cosmetic results, and prompt return to intended use after surgery.

Antimicrobial dosing for common equine drugs: a content review and practical advice for veterinarians in Australia

BACKGROUND

Appropriate dosing with antimicrobial agents is critical for effective treatment and to prevent the development of antimicrobial resistance.

METHODS

A review was undertaken of equine journal articles (Equine Veterinary Journal, Equine Veterinary Education, Australian Veterinary Journal, Australian Equine Veterinarian, Journal of Veterinary Internal Medicine and Journal of Equine Veterinary Science) between January 2015 and August 2018. Those with dosing regimens for procaine penicillin G, gentamicin or trimethoprim-sulfonamide in adult horses were examined and evaluated. Pharmacokinetics and -dynamics of these drugs were also reviewed.

RESULTS & CONCLUSION

The most frequently reported doses for penicillin, gentamicin and trimethoprim-sulfonamide were 20-25,000 IU/kg, 6.6 mg/kg and 30 mg/kg, respectively. Veterinarians treating equine patients in Australia should be aware of the current recommended doses and inter-dosing intervals to ensure efficacy in therapy and to preserve the usefulness of these antimicrobials for the future.

Open standing castration in Thoroughbred racehorses in Hong Kong: Prevalence and severity of complications 30 days post-castration

BACKGROUND

Complications following open standing castration (OSC) in Thoroughbred racehorses are well recognised but variation in their prevalence and severity between populations is not well documented.

OBJECTIVES

To describe the prevalence and severity of complications in the 30 days following OSC.

STUDY DESIGN

A retrospective cohort study of veterinary clinical records relating to horses that underwent OSC between July 2007 and July 2012.

METHODS

Complications were graded on a severity score from N, no complications, to C3, severe complications. Additional data were accessed for each horse including age, import date, racing history, trainer and veterinarian performing the castration. Bacterial culture and antimicrobial sensitivities were performed on a limited number of castration wounds that became infected.

RESULTS

In total, 250 horses were castrated in Hong Kong using the OSC technique over the period of the study. Sixty percent (150/250) of horses experienced some type of post-castration complication, with eight horses experiencing a severe (C3) complication requiring intensive veterinary treatment. Scrotal swelling, funiculitis and seroma formation were present in 70.0%, 36.7% and 24.7% of cases respectively. Most horses experiencing complications required wound reopening (87.3%; 131/150), and/or an extended course of first-line antimicrobials and/or nonsteroidal anti-inflammatory drugs (75/150; 50.0%). Eight horses had cultures submitted for bacterial sensitivity, with 17 bacterial isolates grown. In vitro, the bacteria cultured were sensitive to enrofloxacin (76%; 13/17) and ceftiofur (100%; 17/17). Resistance was detected to penicillin, gentamicin, oxytetracycline, metronidazole and trimethoprim-sulfadiazine.

MAIN LIMITATIONS

Differences in post-castration management cannot be accounted for in this study.

CONCLUSIONS

Complications following OSC in horses in Hong Kong were common. The majority were mild and were successfully treated using antimicrobials and simple wound management. Given the high rate of complications and antimicrobial usage identified in this study, a review of the technique is warranted.

Castration in the standing horse combining laparoscopic and conventional techniques

BACKGROUND

Standing laparoscopic castration without orchidectomy has been shown to be a reliable method of castration in animals with abdominal cryptorchidism, but it cannot be recommended as a method of castration in those with inguinal cryptorchidism or normal males. An alternative laparoscopic method for the castration of horses with descended testes was developed.

OBJECTIVES

To report the results of laparoscopy-assisted abdominal transection of the spermatic cord and a modified open method in the standing horse for castration of descended testes in unilateral abdominal cryptorchids.

STUDY DESIGN

Descriptive case series.

METHODS

Fifteen unilateral abdominal cryptorchids were castrated laparoscopically by performing intra-abdominal ligation of both spermatic cords. The spermatic cord of the cryptorchid testis was not transected. After intra-abdominal transection of the spermatic cord of the descended testis, the testis was removed by an open castration technique in the standing horse. Data collected included time taken to perform the surgical procedure, surgical complications and post-operative recovery.

RESULTS

Abdominal testes were located on the right side in eight horses and on the left in seven. The surgical procedure was easy to perform and few intra- or post-operative complications were seen. Pulse and respiration rates and rectal temperatures remained within normal limits during the evaluation period in all but one animal, which displayed transient pyrexia. The scrotal and laparoscopic incisional wounds healed well without any signs of swelling or exudate. In one Warmblood, there was prolapse of subcutaneous tissue the day after surgery, which retracted in 3 days. The owners were contacted by telephone at 2-3 months after discharge. Post-operative recovery had been uneventful in all horses.

MAIN LIMITATIONS

This study included a small number of cases in which all surgeries were performed by or under the supervision of the same surgeon. Follow-up was limited to telephone reports from owners.

CONCLUSIONS

A laparoscopic technique that is combined with an open scrotal incision to remove the descended testis in the standing horse was developed and shown to be a safe and reliable option for the castration of unilateral abdominal cryptorchids.

Comparison of postoperative complications in healthy dogs undergoing open and closed orchidectomy

OBJECTIVE

To compare closed and open orchidectomy in dogs and the associated complications.

METHODS

A randomised controlled blinded prospective clinical study of 73 cases was undertaken involving the recording of all complications during and in the 10 days following orchidectomy of dogs fulfilling the standardised inclusion criteria. The active variable was the surgical technique of either open or closed orchidectomy.

RESULTS

Dogs undergoing open orchidectomy experienced significantly more complication events than the dogs undergoing closed orchidectomy [24 of 34 (70%) versus 18 of 39 (46%), P = 0 · 04]. Dogs undergoing open orchidectomy were statistically more likely to develop scrotal complications (21 of 34, 61%) compared with dogs undergoing closed orchidectomy (13 of 39, 33%; P = 0 · 02).

CLINICAL SIGNIFICANCE

Open orchidectomy is associated with a higher overall complication rate in the first 10 days after surgery than closed orchidectomy. Open orchidectomy is also associated with increased scrotal complications including swelling, bruising and pain compared with closed orchidectomy.

Standing male equine urogenital surgery

The advantages of performing standing male urogenital surgeries are numerous when compared with performing the same surgery in the anesthetized animal. Some traditional standing male urogenital surgeries, such as castrations, may be faster and cheaper to perform. Laparoscopic standing male urogenital surgeries may allow for improved visualization of the surgical field, decreased hemorrhage, and decreased morbidity and convalescence. Limitations of standing procedures may include increased danger to the surgeon because of fractious behavior of the patient, and increased expense and training associated with instrumentation for specialized procedures such as laparoscopy.