Feasibility and Safety of Canine Orchiectomy Using Scrotal Approach and a Vessel-Sealing Device: A Prospective Observational Study of 200 Cases

Background: Canine orchiectomy involves making an incision in the prescrotal area, exteriorizing both testes via the same incision, ligating the blood vessels and spermatic cord, removing the testes, and suturing the incision. A briefer durations of anesthesia and surgery and decrease of postoperative morbidity could be obtain using a vessel sealing device. The aim of this study was to determine the feasibility and safety of orchiectomy in dogs by a scrotal approach with the use of a vessel-sealing device. Scrotal orchiectomy was performed with the use of monopolar electrosurgery device in pure cutting mode and a vessel-sealing device. Data were collected prospectively for the following categorical variables: breed, age, body weight, lifestyle, surgical time, indications for surgery and complications. Results: No complications were reported in 187 of 200 (93.5%). The complications documented were automutilation (AM), incisional complications (IC) and scrotal complications (SC). AM complications (11/200 [5.5%]) and SC complications (2/200 [1%]) were treated without additional surgery and resolved by day 10 after the surgery. Procedure duration (2,1 minutes± 0.4 minutes) was briefer than traditional castration duration reported in literature (3.5 ± 0.4 minutes). Conclusions: Results suggested that canine orchiectomy by scrotal approach with the use of a vessel-sealing device was feasible and safe. Furthermore, it was associated with a low complication rate and had the benet of reduced surgical time and postoperative morbidity. This technique is promising for widespread application in veterinary surgery to help with haemostasis in canine orchiectomy.

syndrome [11]. Most complications associated with orchiectomy can be prevented by using good surgical technique, including gentle tissue handling, good hemostasis, and aseptic technique [12].
Hemorrhage from poorly ligated vascular pedicles can result in scrotal hemorrhage or intraabdominal bleeding due to the retraction of the bleeding vascular pedicle through the inguinal canal [7]. Traditionally haemostasis is achieved with the use of ligatures but their reported disadvantages are occasional ligature slippage, introduction of foreign matter, di cult management, high cost, size limitation and application time [13]. For these reasons the use of electrosurgical devices with enhanced safety characteristics have gained popularity in small animal surgery [14]. Vessel sealing devices (VSD) achieve haemostasis by the fusion of elastin and collagen in the vessel walls and surrounding connective tissue using moderate compression at a temperature less than 100°C (212°F). The low energy used in theses devices results in less collateral thermal spread and tissue damage when compared to the traditional electrocoagulation devices [15,16]. Ligasure is a feedback-controlled bipolar vessel sealing device that is now well established in human and equine surgery and has been shown to be effective in sealing vessels up to 7 mm in diameter [17].
The aim of this study was to evaluate the feasibility and safety of Ligasure vessel-sealing device for closed orchiectomy via scrotal approach. We hypothesized that the technique will be fast and the complication rates would be low.

Results
The descriptive statistics are reported at Table 1. The majority of the dogs enrolled were privately owned (79.0%, 158/200) and the most common indication for this operation was neutering (92.0% 184/200). 84 dogs (42.0%) weighted less than 10kg while the remaining 116 (58%) weighted more than 10kg at the day of the surgery. The mean duration of canine orchiectomy by scrotal approach using a vessel-sealing device was 2.1 with a SD (standard deviation) of 0.5. Complications were noted in 13 dogs (6.5%) and all of them were reported during the rst 24 hours post-operatively (Table 2).   Tables 3 and 4 respectively. The only variable that was signi cantly associated with complications (including both AMIC and AMICSC) following orchiectomy by scrotal approach using a vessel-sealing device was the weight of the dog. Dogs that were less than 10 kg were 3 times (CI: 0.9-11.3, P = 0.040) more likely to develop complications compared to the dogs that weighted more than 10 kg. There was no variable that showed a trend towards to signi cance thus the multivariable logistic regression did not yield any additional ndings.

Discussion
We hypothesized that the technique will be fast and the complication rates would be low in the study population. The rst hypothesis was supported in that procedure durations was briefer than those reported for traditional prescrotal castration as mentioned by Miller et al (2018) [18] (1,9 minutes ± 0.5 minutes in cases with complications and 2,1 minutes ± 0.4 minutes in cases without complications in this study compared with 3.5 ± 0.4 minutes reported by Miller et al.). Based on this, we concluded that the technique in this study provides a rapid technique for castration. Shorter duration of castration in male dogs using Ligasure were reported also by Faluvégi et al. 2018 [19], but they used a prescrotal approach.
Another hypothesis for the present study was that the complication rate would be low. This hypothesis was supported in that presented technique resulted in no haemorrhagic complications for any of the 200 surgeries performed, and minor complications observed were self-limiting and only few. Based on these results, we concluded that the Ligasure scrotal technique provides a rapid and safe approach for canine orchiectomy.
Major hemorrhage associated with orchiectomy is uncommon in dogs [20], and most complications involving hemostasis result in scrotal hematomas, likely due to oozing from the vaginal tunic with open orchiectomy [1,20]. According to Miller's et al. experience [18], large dogs with large gonads will generally have a larger gonadal blood supply than small dogs with small gonads. Interestingly, dogs that were less than 10 kg were 3 times (CI: 0.9-11.3, P = 0.040) more likely to develop complications compared to the dogs that weighted more than 10 kg in our study. Anyway, the complications were not due to hemorrhage. No hemostatic complications were seen after Ligasure application in our study. The weight of the dog was the only variable that was signi cantly associated with complications (including both AMIC and AMICSC) following orchiectomy by scrotal approach using a vessel-sealing device in this study. We consider the behaviour and temperament of the small dogs to be mostly responsible for incisional complications.
All complications were identi ed at 24 hours post-surgery assessment and resolved without additional surgery. All incisional complications were managed by telephone communication with the owners. None of the owners with incisional complications felt that their dog required additional analgesia. The cases that developed incisional and scrotal complications (dog 46 and 118) were admitted for examination and additional analgesia with NSAIDs and antibiotics were administered. None of the cases required hospitalization or additional surgery. Both complications were encountered in client owned animals. In case 118, the owners were unable to apply the buster collar as soon as automutilation was noticed due to aggression of the dog. In case 46 that both incisional and scrotal complications were also observed, the application of the collar was delayed because the dog was left unattended for several hours. Based on this, we can assume that automutilation is an important factor in the appearance and progression of complications. In the authors' experience, shelter animals had less complications, assuming that the distractions in the environment prevented automutilation or complications passed unnoticed.
In the uncomplicated cases contraction of the scrotum and elimination of the incisional gap was observed by day 3. In all cases that the complications were observed, su cient regression of the scrotum with no incisional gap was observed by day 10. In the cases that both incisional and scrotal complications were observed (46, 118), some skin discoloration remained in the scrotal region by day 10. Nevertheless, the majority of the animals in the study did not require buster collar, and strict exercise restriction was limited to 24 hours post discharge. Interestingly, the limited postoperative restrictions and the avoidance of the buster collar were factors that were strongly appreciated by the owners when they were questioned regarding owners satisfaction. Assessment at 10 days after surgery is routinely performed by several practices but the value of assessment at this time point is questionable due to the fact that the majority of the complications arise the rst days after the procedure [5]. Due to the uncomplicated healing and the rapid elimination of the incisional gap, most owners felt that further assessment was not necessary.
Activation of the vessel sealing system uses electrosurgical radiofrequency energy that causes the collagen and elastin in the blood vessel walls to reorganize within the tissue thereby forming a permanent seal [21]. Monopolar electrosurgery was used to incise the scrotal skin, and to control minor bleeding from septal vessels. Even though skin incisions made with monopolar electrosurgery were associated with decreased healing compared to scalpel made incisions [21], su cient regression of the scrotum and no incisional gap was evident by day 10 in all cases. Clearly bene ts in hemostasis improvements, and overall anaesthesia and surgery time reduction were demonstrated in many studies [22][23][24][25][26][27]. Even though there are reasonable concerns regarding the high cost of using VSD in routine procedures, appropriate re-sterilisation of the hand piece allows a signi cant reduction in the costs by increasing the number of procedures without decreasing safety characteristics [13,28].
Several limitations of the study should be considered when interpreting the results. Some incisional complications could have developed beyond the 24-hour postoperative. Anyway, the owners were instructed to report any complication with the surgery. Similar to our study, in a previous report [5], most complications following canine orchiectomy were discovered at the 24-hour recheck examination and no complications were found at the next recheck examination, performed 10 days after surgery. The authors of the study also advocated for rechecking of patients in the immediate postoperative period and questioned the value of rechecking the patients 10 days after surgery.
We found only one study of postoperative complications after Ligasure orchiectomy in the peer-reviewed veterinary literature, thus, direct comparisons with the ndings of the present study is limited [19]. Moreover, the authors of the study used prescrotal approach, thereby precluding any meaningful comparison with our data.
Another limitation of the study include the use of semiobjective methods for documenting each complication and the fact that the assessment of the majority of the cases was based on owners perception. For these reasons, long-term results should be evaluated in a larger randomized prospective studies.

Conclusion
The low complication rate and time advantage associated with use of the Ligasure technique for orchiectomy of dogs suggested important advantages, including shorter durations of anesthesia and surgery than with the traditional prescrotal technique. We expect that as the Ligasure technique is more widely used, morbidity and mortality rates associated with canine orchiectomy will improve as will savings in resources, such as time and suture materials. The results of the present study provide important data for the veterinarians who perform such surgeries.

Methods
A prospective observational study for canine orchiectomy by scrotal approach using a vessel-sealing device was performed at the CYVETS Veterinary Centre from December 2015 to December 2018. Two hundred healthy intact male dogs were recruited in this study ( Table 5). The age of the study population ranged from 0.8 to 12 years [mean 3.7 years, standard deviation (SD) 2.8] and 149 (74.5%) were crossbreed. Dogs less than seven years old were determined to be healthy based on medical history and physical examination performed on the day of surgery, whilst dogs more than seven years old routine biochemistry and haematology were performed prior to anesthesia to determine health status. The intact male dogs enrolled in the study following a signed consent form by the owners or guardians were presented either from local animal welfare organizations or were client-owned dogs. No dog underwent any procedure speci cally for this study and all procedures were performed in accordance of the Cypriot legislation [The Dogs LAW, N. 184 (I)/2002]. (private/shelter) and the encountered complications up to 10 days post surgery.
All protocols were standardized prior to commencing the study. These included: preparation for aseptic surgery, surgical procedure, recovery protocol, postoperative instructions and client communication.
Orchiectomy time was measured from immediately prior the skin incision to apposition of the incision site and dogs were categorized based on body weight into small (< 10kg), medium (10 to 20 kg) and large breed (> 20 kg). Associated surgical complications were documented including automutilation, incisional complications (hemorrhage, bruising, swelling, erythema) and scrotal complications (swelling, bruising, hematoma). The treatments/measures employed to address the encountered complications were buster collar application (BC) and ice packs (IP) in all complications and additional analgesia with non-steroidal anti-in ammatory medication and antibiotics in the cases with combination of incisional and scrotal complications.

Perioperative management
All dogs were anaesthetised by use of standard clinical protocols. Young healthy dogs were premedicated with 0·02 mg/kg medetomidine (Domitor P zer) intravenously (iv) and 0·02 mg/kg butorphanol (Dolorex Merck) iv. Induction to anesthesia was achieved with 1 to 3 mg/kg propofol (Propofol 1%, Fresenius pharma) slowly iv to effect and maintained with 2% inspired iso urane (iso o 100%, Abbott pharma) in oxygen with the use of a Bain circuit. In patients over 10 years old, medetomidine was replaced by 0·2 mg/kg midazolam (Dormicum Roche) iv. Anaesthesia was monitored by clinical assessment and a multi parameter anaesthesia monitor. All dogs received 0·2 mg/kg meloxicam (Metacam Boehringer) iv before anesthesia. Additional analgesia with butorphanol was administered after surgery in patients with evidence of pain (WSAVA, 2014). A small square area around the incision site was clipped with slow-powered clippers with 0,5mm blade. Care was taken not to traumatize the sensitive scrotal skin during clipping. The skin was prepared with surgical scrub (Dermanios Scrub CG, Anios lab) followed by 2% Chlorhexidine Digluconate solution (Chlorhexidine Concentrate 5 vol. % CD, Krusan). The patients were positioned in dorsal recumbency and draped with a round fenestrated self-adhesive drape.

Surgical procedures
The left testicle was grasped between the thumb and index of the surgeon and directed caudoventrally while pulling the scrotal skin taut over the testicle. The scrotal skin cranial and ventral to the median raphe at the apex of the scrotum, was incised with a monopolar electrosurgery device (Eschmann TD830), in pure cutting mode at 100-150W output (small and medium-large patients respectively), approximately one-third of the length of the long axis of the testicle (0,5 − 2 cm) (Fig. 1A). The incision was continued through the spermatic fascia until the parietal tunic was seen. The testicle within the parietal layer of the vaginal process was exteriorised, and the spermatic cord was exposed by re ecting all visible connective tissue from the parietal tunic with a gauze sponge. A 10-mm instrument (LigaSure Atlas Sealer/Divider-LS10) connected to a bipolar, feedback-controlled vessel sealing device (LigaSure Generator-Valleylab, Boulder, Colorado, USA) with a power setting of three bars was applied to the spermatic cord and the instrument was activated to achieve hemostasis (Fig. 1B). The sealing and transection time was less than 5 seconds per cord, appreciably faster than suture ligation. After hemostasis was completed, the spermatic cord was transected with scissors and the stump was returned to the scrotum (Fig. 1C,D). The second testicle was removed using the identical technique. After completing the procedure the skin was opposed by gentle approximation of the incision edges (Fig. 1E).

Postoperative care
All dogs were hospitalised for 6-8 hours after surgery. During this period they were closely monitored for signs of pain, haemorrhage and swelling of the surgical site. The assessment of the amount of pain was carried out hourly and was based on the observation of the demeanor and posture of the animal in the kennel and during the interaction with the dog while examining the wound for signs of surgery associated compilations. Following discharge from the clinic, all owners were instructed to rest their dogs for 1 day. Short lead walks four to ve times a day for toileting were permitted. Progressive return to exercise over one week was advised, if healing was uncomplicated. Owners were instructed not to dress or treat the wound. A buster collar was provided to the owners but it was not applied to the animals. Owners were advised to monitor the surgical wound twice daily and apply the buster collar and contact the members of the staff if self-trauma, discomfort or swelling were evident at the surgical site.
Follow up phone calls to the owners were conducted on day 1 after discharge and on day 10. An additional phone call was conducted on day 5 in the cases that any complication was reported. During the communication, a standard questionnaire format was employed and the owner's comments were documented.

Statistical analysis
Data were recorded into Microsoft O ce Excel 2016 and then imported into SPSS (version 22.0; SPSS Inc., Chicago IL, USA) for statistical analysis. Descriptive statistics were performed for the continuous variables of age and duration of surgery, as well as for the following categorical variables: breed, body weight (small, medium and large), lifestyle (private or shelter), indications for surgery (neutering, prostatic disease, testicular disease and other) and complications (none, AMIC, AMICSC). Independent t-test was used to evaluate for associations between continues variables and complications. To investigate any association for complications and categorical variables a univariable analysis conducted using Chi-square test. A multivariable logistic regression was performed to test for possible risk factors associated with complications. The independent variables that yielded P-values of < 0.2 in a univariable analysis were then tested in a multivariable logistic regression analysis. A P-value ≤ 0.05 was considered statistically signi cant. The P-values with odds ratio (OR) and 95% con dence interval (CI) were reported. The study was carried out in compliance with the ARRIVE guidelines.

Consent for publication
Not applicable.

Availability of data and materials
All data generated or analysed during this study are included in this published article.

Competing interests
The authors declare that they have no competing interests.

Funding
Not applicable.
Authors' contributions CY, CO and JM made substantial contributions to the conception of the study design, acquisition, analysis and interpretation of data; MP and TV contributed to the data analysis and critically revised important intellectual content. All authors read and approved the nal manuscript.