Prevalence of complications associated with use of the Henderson equine castrating instrument

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.

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.

Intratesticular mepivacaine versus lidocaine in anaesthetised horses undergoing Henderson castration

BACKGROUND

In horses undergoing castration, direct comparison of intratesticular lidocaine vs mepivacaine as analgesic adjuncts has not yet been analysed.

OBJECTIVE

To compare the effects of intratesticular lidocaine and mepivacaine during equine castration using the Henderson drill under total intravenous anesthesia.

STUDY DESIGN

Randomised, double-blinded clinical study.

METHODS

Thirty-four stallions were anaesthetised using xylazine-ketamine and randomly selected to receive 10 mL either lidocaine or mepivacaine injected into each testicle. Both surgeon and anaesthetist were blinded to the selected treatment. A total of 5 minutes were required to pass between injection and first incision. Routine castration using a Henderson drill was performed. Heart rate, respiratory rate and SpO₂ were serially recorded. Total surgical time, time prior to clamping of each testicle and time to second incision were recorded. Cremaster muscle relaxation, surgical quality scores, number of additional ketamine boluses, recovery time and recovery quality were assessed between groups.

RESULTS

Cremaster relaxation scores were significantly better for the mepivacaine group over the lidocaine group on a 1-3 scoring system (1 being most relaxed, 3 being least). The average cremaster relaxation score on both testicles treated with mepivacaine was 1 compared to the lidocaine treatment averaging 2 [P = .03 first testicle; P = .04 second testicle]. The lidocaine group had an increased number of horses requiring additional ketamine (25% of horses) compared to the mepivacaine group (16% of horses). No other significant differences were observed between the groups.

MAIN LIMITATIONS

The use of only one injection method and lack of post-operative pain scoring limit the conclusions that can be drawn from these results.

CONCLUSION

Intratesticular mepivacaine when compared with intratesticular lidocaine results in improved cremaster muscle relaxation when only waiting five min prior to the start of the procedure.

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.