Experimental application of surgical technique for perineal urethrostomy in male cats

22 Nong Lam University, Ho Chi Minh City Experimental application of surgical technique for perineal urethrostomy in male cats Ha T. T. Le1, Thao L. N. Nguyen1, Luan N. Nguyen1, Han M. Ly1, Vu P. Huynh2, & Thong Q. Le1∗ 1Department of Clinical Veterinary Medicine, Nong Lam University, Ho Chi Minh City, Vietnam 2Department of Animal Health, Binh Duong, Vietnam ARTICLE INFO Research paper Received: March 04, 2018 Revised: May 10, 2018 Accepted: June 02, 2018 Keywords Male cats Normal urination Perineal urethrostomy Surgery ∗Corresponding author Le Quang Thong Email: lqthong@hcmuaf.edu.vn ABSTRACT The objective of this study was to evaluate the efficiency of PU in male cats. The perineal urethrostomy (PU) was performed in 10 home-breed male cats, in which 9 cats were healthy and 1 cat had cystolith (2.5 ± 0.5 kg BW), from May 2017 to April 2018 at the Department of Clinical Veterinary Science of Nong Lam University, Ho Chi Minh City. The cri- teria for evaluating the experiment included the successful rate, wound healing time, post-operative pain assessment, time of return to normal urination and defecation and post-operative short-term complications. The results showed that 9 out of 10 cats completely recovered their urinating ability in approximately 14 days post-operation, in which 2 cats experienced wound infection and required a surgical intervention. One cat died due to unknown causes at the 10th-day post operation. The average pain scores based on the Feline Glasgow Composite Mea- sure Pain Scale (CMPS – Feline) in the first 5 days were relatively high (scored as 11) and gradually decreased; until 14 days postopera- tion, 100% of cats recovered had no sign of pain (scored as 1). It was recorded that all cats experienced pain and difficulty in urination and defecation for a few days after the surgery. After removing the urinary catheter, the cats needed 3 to 5 days to get used to the new urethral stoma and normally self-urinated ability. In general, the successful rate of this surgical method was 90% (9 out of 10 fully recovered cats) in which most of the cats were healthy and returned to normal urination after 14 days post-operation. Cited as: Le, H. T. T., Nguyen, T. L. N., Nguyen, L. N., Ly, H. M., Huynh, V. P., & Le, T. Q. (2018). Experimental application of surgical technique for perineal urethrostomy in male cats. The Journal of Agriculture and Development 17(3), 22-28. 1. Introduction Nowadays, one of the most common concerned health problems of cats was the obstruction of urinary tract, especially in male cats. The Os- borne‘s research indicated three percent (3%) of dogs seen at veterinary hospitals in the USA were affected by urolithiasis while these figures were over 7% of the feline case (Osborne et al., 1995). Therefore, it could be seen that the uri- nary obstruction rate was higher in cats than in dogs. Moreover, because of the narrow and long urethra of cats, male cats have a higher risk of urinary tract infection, urolithiasis or many life- threatening conditions related to the urinary sys- tem and the bigger chance of recurrence of those conditions. The urethral anatomy of a male cat is divided into 3 main parts: the pre-prostatic (close to the urinary bladder), post-prostatic and penile ure- thra. These parts are orderly arranged based on the decreasing size of the lumen diameter: 2 mm, 1.3 mm and 0.7 mm, respectively (Cullen et al., 1983). Because urinary tract diseases occur commonly in male cats, treatment methods require a plenty The Journal of Agriculture and Development 17(3) www.jad.hcmuaf.edu.vn Nong Lam University, Ho Chi Minh City 23 of time, work, and money. The cured animals have to suffer physical and mental pain (for in- stance in the case that the animal has recur- rent the urinary tract infection (UTI) and needs catheterization). That is why finding and apply- ing another supportive solution for treating uri- nary diseases in male cats are extremely neces- sary. Many methods are used to treat urinary dis- eases in cats including changing diets, increas- ing the water intake, medication and operation to remove the urinary stone. However, there are cases in which the urethra is completely blocked and catheterization cannot be applied due to the obstructive object that locates at the extremely narrow part. Most of the above treatments are unable to apply. Regarding the previous researches, the per- ineal urethrostomy technique was firstly studied in 1963 by Carbone and modified in 1971 by Wil- son & Harrison as a support treatment for urinary tract diseases in male cats. It was also a surgical treatment (Carbone, 1967; Blake, 1968) that ef- fectively worked on severe traumatic penile cases. The technique was described as an artificial for- mation of a new bigger urine pathway after re- moving the penis and suturing the inner layer of the urethra with the perineal skin that allowed for obstructed materials to pass through. Until now, there have not been any studies re- lated to PU technique in Vietnam yet. This study was conducted to assess the successful rate and the recovery time of normal urination and defe- cation of cats after surgery. This would be offered offer more data about an alternative solution to assist the treatment of urinary tract diseases for eterinarians in Vietnam. 2. Materials and Methods The study was conducted from May 2017 to April 2018. Nine healthy intact male cats and 1 intact cat with bladder stones (BW from 2.5 ± 0.5 kg) were undergone the perineal urethrostomy surgery at the Department of Clinical Veterinary Sciences of Nong Lam University, Ho Chi Minh City. All cats were fed the same diet for one week and dewormed before the surgery. The evaluation criteria included the compli- cations rate during and after the surgery (%), the time period to recover the ability to urinate and defecate, the time period of wound healing (days), the pain assessment based on Glasgow Fe- line Composite Measure Pain Scale (score), the success rate of surgery (%). 2.1. Surgical procedure 2.1.1. Before surgery All of the cats before surgery must undergo the process of fasting of food for at least 8-12 hours and water for at least 3-4 hours, and were gener- ally checked for their health conditions (tempera- ture, respiratory rate and heart rate) in order to assure their appropriate condition for anaesthe- sia. The cats were administered with atropine (0.2 mg/kg, IM) as premedication, Cefotaxime (25- 50 mg/kg, IM) 30 minutes before surgery and 5 mg/kg IV of Zoletil during the induction of surgery. The cats’ fur was shaved off from the navel to the whole groin and extended around 5-10 cm to the tail. Then, they were positioned supinely with the hip lifted a little bit by a pad under the back. Their hind limbs were fixed to- wards the front limbs in order to fully expose the surgical site. The surgical site was sterilized with Povidine 10% solution mixed with NaCl 0.9% so- lution, and was placed upon with a surgical clamp to ensure the complete sterilization. 2.1.2. During surgery First, an ellipse incision was made around the scrotum. Then, the subcutaneous tissues were separated and the testes were removed in the manner similar to the procedure for common male cats’ castration. The scrotum and testi- cles were also discarded. After that, the retrac- tor muscle was cut in order to release the penis (Figure 1). In the next step, an urinary catheter with Vase- line at the end was gently inserted into the penis to the bladder. The urine inside was drawn out slowly using a 5-cc syringe, which was kept in- tact to the end of the urinary catheter to prevent urine from dripping and contaminating the sur- gical site. Then, ischiocavenosus muscle, lying on the sides of the penis was identified by separat- ing the perineal muscle area. In order to check whether the right muscle was found, the penis was moved a little bit (Figure 2). After being identified, the muscle was cut, so that the penis, which was hanging loosely from the perineal mus- www.jad.hcmuaf.edu.vn The Journal of Agriculture and Development 17(3) 24 Nong Lam University, Ho Chi Minh City Figure 1. Penis was released by incising retractor muscle. Figure 2. Identifying ischiocavenosus muscle. cle, must be held straight by tissue forceps. Next, an incision was made with a scalpel on the penis ventrally based on the urinary catheter from the glans penis to a position around 3 mm from the bulbourethral gland (Figure 3). Before safely cut- ting off the penis, transfixation ligature was tied tightly. After the above 8 steps of the surgery, the method of cutting penis was improved by using a pair of scissors to cut along the penal shaft in- Figure 3. Scalpel was used to cut along the penal shaft based on the urinary catheter. Figure 4. Urethra was cut by using scissor without the support of a urinary catheter. stead of using scalpel as in the above mentioned method (Figure 4). In the final steps, the urethral mucosa and the nearby most dorsal skin area were sutured together at 3 positions (10, 12 and 2 o’clock) cranially with a simple interrupted pattern (Fig- ure 5). Here, it is obliged to make sure that the mucosa, muscle tissue and skin were all sutured simultaneously. The urinary catheter was with- The Journal of Agriculture and Development 17(3) www.jad.hcmuaf.edu.vn Nong Lam University, Ho Chi Minh City 25 drawn and the surgical site was closed up rou- tinely from the suture at 12 o’clock towards the abdomen. The urinary catheter was once more inserted into the urethra and fixed position with 4 suture lines lying symmetrically by the catheter (Figure 6). Figure 5. Suturing the mucosa and the nearby skin at 3 positions. Figure 6. Suturing the mucosa to the nearby skin. The wound was sterilized and bandaged care- fully. The cats were obliged to wear Elizabeth collar post-operation throughout the healing pro- cess. 2.1.3. Post-operation care After surgery, the cats were administered meloxicam (anti-inflammatory) for 5 consecutive days, cefotaxime for 5-7 consecutive days, and Lactate Ringer or glucose 5% intravenously is needed. The condition of the surgical sites (su- tures, fluid, healing process. . . ), and the general health condition (pain score, temperature. . . ) were evaluated and documented. In case of a good healing process and as well as a regained abil- ity to urinate on their own, the urinary catheter was withdrawn on day 5 and the sutures were removed on day 14. In case of complications due to the sutures being ruptured by the cats which caused necrosis at the surgical site, another surgery was required to place back the urinary catheter as well as the care routine. All 10 cats were kept strictly in cages to restrict their move- ments. For the cats which did not defecate in the first 3 days after surgery, Duphalac and laxative catheter were required. As for the food, the cats were given a diet con- taining high levels of easily digested nutrients. For the cats which suffered from anorexia, intra- venous fluid transmission and nutrition gel were obliged. 2.1.4. Pain assessment method The cats’ pain was daily rated post-operation according to Glasgow Feline Composite Measure Pain Scale: CMPS – Feline (Jacky, 2015). This method comprises of answering a series of 20 questions about the reaction and the behaviors of the cats in order to rate how much it was hurting them on the 20-score scale. In case they scored over 6, they would be classified as painful and analgesic measures must be taken. 3. Results And Discussion 3.1. Complications rate during and after surgery Complication rate after surgery was displayed below in Figure 7, which consists of surgical site infection (36%), urethra blockage (21%), hema- turia (7%), uncontrolled urination (7%), surgical site tearing (7%), and no complications (21%). www.jad.hcmuaf.edu.vn The Journal of Agriculture and Development 17(3) 26 Nong Lam University, Ho Chi Minh City Our results was consistent with complications re- ported in researches of Hauptman (1984), Smith (2002), & Bass (2005). Figure 7. Complications rate after surgery. The most commonly seen post-surgery com- plication was surgical site infection. There were in total 5 cases with the presence of pus which usually appeared on day 5 after withdrawing the urinary catheter. This, in turn, caused the urine to drop directly onto the surgical site, weaken- ing the adhesion between the urinary mucosa and the skin. The amount of pus depended on the po- sition of the surgical site combined with other complications such as wound dehiscence or uri- nary incontinence. This agreed with the findings of other studies (Baines et al., 2001). The first case, due to the lack of experience, the surgi- cal site was located near the anus, causing the consecutive discharge of inflammatory fluid for 8 days after surgery. There were 3 out of 10 cases in which the Elizabeth collar was slipped, allow- ing the cats to lick and bite at the surgical site, causing the rupture of the suture, bleeding and prolonging the healing process. There was a case in which the cat lost its ability to urinate on its own due to being in pain, making the urine to drop on the surgical site and extend the healing process (8 days post-surgery). In cases of surgical site infection, the wound was cleaned regularly with saline solution and Po- vidine iodine, and bandaged to prevent the con- tact with the cage floor. Plus, antibiotics were also used for 5-7 days to minimize the infec- tion. The cage floor bars were disinfected with disinfectant-VirKon. In cases of surgical site tear- ing, the following surgery was performed to re- move necrotic tissues, suture back, and replace the urinary catheter. In case no. 8, there was a stricture of the newly formed urinary opening, due to the cat biting the suture and tearing the surgical site, which widened the necrotic area. Therefore, it was dif- ficult to distinguish the position of the previous surgical site, as well as to suture the wound, caus- ing a stricture. During the healing process, the urinary opening was narrowed down, and covered by a layer of scab, making the cat difficult to uri- nate without the aid of urinary catheter. After cutting the sutures and clearing off the scab, the cat’s urinary ability returned to normal. In case no. 10, during post-operation care, hematuria was spotted on the first 2 days but was gone later on. Hence, in spite of operating on a cat with bladder stones, there were no huge changes in the post-surgery parameters. 3.2. Evaluation of the time period to recover the ability to urinate and defecate The average time for cats to recover the ability to urinate and defecate was 10.6 and 5.2 days, respectively (Table 1). Throughout the first few days after surgery, all 10 cats showed symptoms of being in pain, and difficulty in urinating and defecating by pushing because they were used to their new urinary flow yet. After removing the fixed urinary catheter, the cats needed aid in catheterization for 3-5 days on average, whereas some of them recovered faster and were able to urinate right after catheter removal (2/10). However, in the first case, due to the surgical site being very close to the anus, the wound was strained during the cat’s excretion process, hurting it to the point it refused to defe- cate or urinate. Therefore, the healing process in this case was extended to 19 days. In case no. 8, as a following surgery was needed to create a new urinary opening, the time period to recover the urination ability was reset and it took longer than the other 9 cases. In order to encourage the cats to use their newly formed urinary stoma as well as to recover their defecating ability, they were provided with plenty of water and were limited to catheterize by urinary catheter and defecating catheter. 3.3. The time period of wound healing and the pain assessment On average, the cats’ wounds took up around 9 to 21 days to heal, based on the 9 surviving cats after surgery as the cat no. 3 died with no appar- ent reason. There were 7 out of 10 cats with the wound completely healed on day 17. In cases of cats with infected wound which required a further The Journal of Agriculture and Development 17(3) www.jad.hcmuaf.edu.vn Nong Lam University, Ho Chi Minh City 27 Table 1. The time period to recover the ability to urinate and defecate of cats after surgery Cats 1 2 3 4 5 6 7 8 9 10 Average Return to normal defecation 14 10 0 4 3 8 2 5 2 4 5,2 Return to normal urination 19 5 0 9 10 8 8 31 6 10 10,6 surgery, the healing time would be prolonged (31 days) (Figure 8). Wounds that healed completely had a bigger diameter of the new urinary opening than their glans penis. This would play a huge role in bene- fiting the cats’ urination due to bigger urine flow than normal cats (Figure 9). Figure 8. Wound healing time after surgery. Figure 9. The new urinary opening after 21 days. 3.4. The pain rating evaluation after surgery Based on Glasgow pain scale, the pain rate of cats after surgery would fall around 9 to 13, in which, 40% of them scoring 9, 20%, scoring 11 and 13, 10% scoring 10 and 12. On the subse- quent days, the pain rate decreased gradually un- til reaching 1 on day 14. However, in cases with a further surgeries (cat no. 6 and 8) or with suture rupture sooner than planned (5 days), the pain rate was reset on the next surgery. In general, after surgery, the cats suffered from a great deal of pain. Accordingly, they were provided with analgesic measures such as anti-inflammatory medicine, Meloxicam in order to calm them down, minimizing the strain of wounds. 3.5. Improvement of surgical techniques The surgical technique was introduced by Wil- son & Harrison (1971), we have had 2 improve- ment in the modified surgical technique, which helped the healing time and the operation time shorter. Improvement of urethra opening location ex- pression: In the first case, the penis was only 1mm away from the bulbourethral gland, the cat suffered from great difficulty in defecating in the early stage of the healing process, with feces kept coming out uncontrollably. This, in turn, pro- longed the healing time compared to the cases in which the penis was cut 3 mm from the bul- bourethral gland. Improvement of surgical technique: Cutting along the penal shaft without urinary catheter inside by a pair of scissors was proved to be more effective than using a scalpel which was based on the urinary catheter, as it helped saving surgery time, anesthesia as well as easing the surgeons because of a much cleaner cut. 4. Conclusion The results from this study indicated the PU technique has highly successful rate with 9 out of 10 cats recovered completely after 9 to 21 days. The male cats returned to normal urinary and defecate frequency ability within 10.6 days and 5.2 days, respectively. The complications could be www.jad.hcmuaf.edu.vn The Journal of Agriculture and Development 17(3) 28 Nong Lam University, Ho Chi Minh City controlled by giving a good post-operative care, pain relief or surgical intervention in some severe cases. The research has provided new information of a surgical method and gave more choices for Vietnamese veterinary practitioners in relieving severe urethral obstruction cases in male cats. Acknowledgement The authors would like to express our great appreciation to the Office of Science Research Management and Veterinary Teaching Hospital - Nong Lam University for supporting this re- search. 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