Abstract
Case series summary
Medical records were reviewed for cats that underwent a perineal urethrostomy performed in dorsal recumbency for the treatment of urethral obstruction. Information, including signalment, reason for presentation, number of previous obstructions, surgery time, and perioperative and postoperative complications, were collected through a review of medical records and owner follow-up. The objective was to evaluate short- and long-term complications in cats that underwent perineal urethrostomy performed in dorsal recumbency for treatment of urethral obstruction.
Relevance and novel information
No major or life-threatening complications, such as urethral stricture, re-obstruction, euthanasia due to lower urinary signs or chronic urinary tract infection, were reported. Short-term complications were limited to dysuria in 2/12 (16.7%) cats. Long-term follow-up was available for nine cats. The most common long-term complication seen in this population of cats was a single recurrence of urinary tract infection in 3/9 (33.3%) cats that resolved after a short course of empirical antibiotic therapy. Performing perineal urethrostomy in dorsal recumbency is safe and may have advantages to ventral recumbency due to improved visualization, allowing for more efficient dissection and improved accuracy in tissue apposition during closure. We believe this has been a major contributor to our reported reduced major postoperative complication rate.
Introduction
Feline lower urinary tract disease (FLUTD) is common in male cats. Buffington reports that the term FLUTD may be misleading because the disease process is thought to be a more complex systemic disorder often related to stress and environmental changes.1,2 Clinical signs of FLUTD can be non-obstructive or obstructive and include hematuria, dysuria, stranguria, pollakiuria, inappropriate urination and complete urethral obstruction.1–4 Approximately 18–58% of cats with FLUTD will become obstructed, and of those cats 22–36% will obstruct for a second time within 6 months.2,5,6 The underlying cause for FLUTD is often not identified, and idiopathic FLUTD is diagnosed in about 57% of cases.3,4
Many surgical techniques have been described to relieve urethral obstructions in male cats.7–9 Surgery alone does not prevent signs of FLUTD from recurring and must be combined with appropriate medical management (dietary modifications and environmental changes) for optimal results.2,5 Perineal urethrostomy (PU) is a surgical procedure reserved for male cats that have recurrent lower urinary tract obstruction and have failed medical management or obstruction due to urolithiasis, distal urethral trauma or neoplasia.2,5,10–13
The goal of the procedure is to bypass the narrow distal urethra by creating a permanent stoma. This stoma is created by amputation of the narrow, distal penile urethra and creating a larger diameter opening by direct apposition of the urethral mucosa to the perineal skin.2,13–15 The penile urethra is about twice the diameter at the bulbourethral glands, which is the level to which the urethra is dissected.10,14,16 The technique, originally described by Wilson and Harrison, 7 requires first intention healing of urethral mucosa to the perineal skin to prevent urine extravasation, inflammation and urethral irritation to prevent urethral stricture and reobstruction.2,7,10,16
This procedure and its complications have been well described when the procedure is performed in ventral recumbency.2,11,17 Complications previously reported include urinary tract infection (UTI), urethral strictures, cystitis, wound dehiscence, urine scald dermatitis, urinary and fecal incontinence, perineal hernia and rectal prolapse.4,5,15 Many of the previously reported complications have been suggested to have been the sequelae of suboptimal surgical technique, tissue handling and/or inappropriate owner compliance after surgery.2,10,17 We hypothesized that by performing the surgery in dorsal recumbency, the surgeon would have better visualization for critical dissection and improved apposition required in this procedure, allowing for decreased surgical time and with fewer short- and long-term complications, when compared with previously reported studies. To our knowledge, there is no reported long-term (>1 month) follow-up of cats that have had a PU performed in dorsal recumbency.
Materials and methods
Medical records of Austin Veterinary Emergency and Specialty Center were searched to identify all cats that underwent PU between December 2015 and September 2018. Cats were included in the study if the PU had been performed in dorsal recumbency for resolution of lower urinary tract blockage due to FLUTD or urolithiasis, the medical record was complete and available for review, and the cats had a minimum follow-up time of 7 days following surgery.
Information collected from the medical records of cats in the study included age, breed, weight, composition of urinary stones (if applicable), whether or not a UTI was present at the time of surgery (based on urinalysis or results of urine culture), number of previous obstructions prior to surgery, surgical time, surgeon performing the procedure, and perioperative complications. All surgeries were performed by a board-certified surgeon or a residency-trained doctor.
Follow-up
Follow-up information was collected through review of medical records and by contacting owners. Short-term follow-up was considered to be <1 month and long-term follow-up was considered to be >1 month. Complications were considered minor if they resolved with medical management alone and major if they required surgical revision or euthanasia.
Owners were contacted via email or telephone for a follow-up interview. Owners who were able to be reached were asked about recurrence of lower urinary tract signs in their cat and the quality of life for their cat after surgery.
Surgical procedure
All PU procedures were performed based on the technique previously described by Wilson and Harrison with the modified dorsal positioning described by Tobias.7,16 All surgeries were performed in dorsal recumbency with the perineum parallel to the operating table and pelvic limbs pulled cranially.
A voiding cystourethrogram was performed in one case postoperatively owing to suspected urethral tear during attempts at preoperative catheterization. A second procedure (mass removal) was performed in one case. All patients were recovered with an Elizabethan collar in place and with strict instruction to not clean the stoma site by staff or clientele.
Results
Fourteen cats had a PU during the time period between December 2015 and September 2018. All cats identified had the procedure performed in dorsal recumbency. One cat was excluded from the study owing to euthanasia 7 days postoperatively due to progressive acute renal failure. A second cat was excluded from the study owing to loss of follow-up after initial discharge from the hospital.
All cats included were castrated males. Breeds represented included domestic shorthair (n = 8), domestic mediumhair (n = 2), one Russian Blue and one Munchkin. Median age was 5.2 years (range 1–17 years) and median body weight was 5.1 kg (range 3.2–6.9 kg). Urethral obstruction was the presenting complaint for all cats.
Nine cats had episodes of previous obstructions, suspected to be due to idiopathic FLUTD. Four cats had three previous blocking episodes, two cats had two prior occurrences, and three cats were obstructed one other time prior to surgery.
The majority of the cats were diagnosed with idiopathic FLUTD (n = 11/12 [91.6%]). One (8.3%) cat was diagnosed with struvite urolithiasis based on stone analysis. Eleven cats had a urinalysis completed during hospitalization and 10 cats had urine cultures performed at presentation or at the time of surgery. The most common urinalysis findings were proteinuria and crystalluria, identified in 7/11 (63.6%) cats. Struvite crystals were identified in 4/11 (36.3%) cats and amorphous crystals noted in 3/11 (27.3%). One (9%) cat had both struvite and amorphous crystals. Bacterial rods were present in only one cat.
Five (41.7%) cats were determined to have UTI based on urinalysis or urine culture. Specific pathogens identified on urine culture included Escherichia coli (n = 3), Staphylococcus pseudintermedius (n = 1), Enterococcus species (n = 3) and Pasteurella species (n = 1). One cat grew E coli, S pseudintermedius and Enterococcus species, and another grew both Enterococcus species and E coli. Six cats had no growth on urine culture, and two cats did not have a urine culture performed at presentation to the hospital or at the time of surgery.
All surgeries were performed by a diplomate of the American College of Veterinary Surgeons (ACVS) or an ACVS small animal surgery residency-trained doctor. Total average surgical time was 44.1 mins; surgical time ranged from 18 to 78 mins. One patient underwent a voiding cystourethrogram after surgery owing to concern for urethral tear in the preoperative attempts at catheterization. Total surgical time for this cat was 62 mins followed by cystourethrogram. A patent lower urinary tract was confirmed after contrast study. One patient had urohydropulsion performed in the immediate postoperative period for removal of uroliths, and a different patient had a second procedure (mass removal); cystotomy was not indicated in any patient in this study. Significant preoperative urethral trauma (edema and multiple lacerations) was noted in one cat.
Minor perioperative complications were reported in two (16.7%) cats. These two cats were observed to be straining in the immediate postoperative period, one with macroscopic hematuria. The remaining 10 cats had no perioperative complications reported. No major complications (urethral stricture, re-obstruction) were identified. A summary of the results can be found in Table 1.
Summary of results
UTI = urinary tract infection; NP = not performed
Follow-up time after discharge from hospital was available for all 12 cats and ranged from 7 days to 36 months (average 356.2 days). Short-term follow-up was available for all 12 cats. Long-term follow-up was available for nine cats. Follow-up data were collected by review of medical records combined with owner questionnaire. Only five owners were able to be reached for further follow-up.
For the three cats with only short-term follow-up available, time to follow-up was 7, 12 and 21 days, respectively. At the time of follow-up, all three cats had returned to normal urination habits, including no dysuria, and surgical sites were noted to be apposed without evidence of dehiscence or urinary extravasation and cellulitis.
For cats with long-term follow-up available, recurrent UTI was the most commonly identified complication, occurring in 3/9 (33.0%) cats; only one recurrence was recorded for each of these cats. All three cats were diagnosed with UTI recurrent lower urinary clinical signs, including straining to urinate, pollakiuria or inappropriate elimination and were treated with empiric antibiotic therapy. UTIs combined with clinical signs resolved for all three cats. Two cats had a urinalysis performed at routine check-ups and had no evidence of UTI. Five of nine cats with long-term follow-up were prescribed a urinary diet by their primary veterinarian. Only one of these five cats had recurrent signs of FLUTD (straining to urinate, UTI).
All owners were contacted via email and telephone and invited to answer questions regarding recurrence of lower urinary tract signs and quality of life for their cat following surgery. Five of 12 clients were able to be reached. All five cats for the clients who answered the survey were still alive. When asked about recurrent lower urinary tract signs (pain, stranguria, hematuria, pollakiuria), one owner reported spotting of blood and the remaining four reported no recurrence. Four owners thought that their cats had an excellent quality of life after the surgery.
Discussion
PU is a commonly performed procedure in male cats for treatment of recurrent urethral obstruction. The procedure has been described being performed in dorsal recumbency only when concurrent cystotomy is required. It is standard to perform PUs in dorsal recumbency for all cats at our institution, whether or not cystotomy is needed.
Two patients experienced dysuria in the immediate postoperative period; however, other common short-term complications, including incisional dehiscence, stricture and urine leakage, were not reported in this study.4,10 Previously reported complication rates include an average of 25% short-term complications and 28–57% long-term complications. 10 The minor complication rates reported in this study were similar to previously reported rates, with 16.7% (n = 2/12) of patients having minor perioperative complications and 25.0% (n = 3/12) of patients having reported recurrent UTI as minor long-term complications; however, no major short- or long-term complications were reported.
Clinical signs of FLUTD are likely to recur whether or not a PU was performed.10,14,18 Long-term complications including recurrence of idiopathic FLUTD, UTI and stricture have been reported with frequencies of 28–66%.2,4 In our study, postoperative stricture was not identified. Urethral stricture has been reported in up to 18.1% of cases and is usually due to poor surgical technique: incomplete dissection to the bulbourethral glands, incomplete transection of penile attachments to the ischiocavernosus muscles and poor mucosa-to-skin apposition.2,10,17 We believe that performing the PU in dorsal recumbency has contributed to the lower complication rate reported in this study.
Our study failed to identify any major surgical complications due to structure, re-obstruction or dehiscence. We propose that improved visualization allows for optimal dissection and improvements in the surgeon’s ability to accurately and efficiently appose the urethral mucosa to the incisional margin of the skin. Surgical positioning may be a contributing factor for no strictures in this population of cats. No urinary catheters were placed postoperatively, and all cats were also recovered with an Elizabethan collar, eliminating the potential for self-trauma, which has also previously been proposed to reduce postoperative complications of strictures.15,19
Recurrent UTI was the only long-term complication reported in this study. There have been previous reports of increased UTIs in cats that have had PU with proposed etiology thought to be related to underlying uropathy, trauma of catheterization and the alteration in anatomy allowing a larger area of urethral mucosa to be exposed.6,18,20
Absorbable suture with combined simple interrupted and simple continuous patterns was used on every cat in this study. No complications, such as dehiscence or recto-urethral fistula were reported. The use of absorbable suture has been proven to be effective when performing PUs, eliminating the need for sedated suture removal, which adds to stress and possible trauma at the mucocutaneous junction.10,21,22 No cats in this study required suture removal; all absorbable sutures were allowed to fall out or dissolve on their own.
Kagan et al first described performing the PU in dorsal recumbency; however, it is still most commonly reported to be completed in ventral recumbency.2,11,17,21 By performing the procedure in dorsal recumbency, there is no need for repositioning if concurrent cystotomy is required, decreasing anesthesia time. Slunsky et al reported a significant decrease in diameter of the vertebral canal in patients placed in ventral recumbency with tail hyperextended and pulled cranially. 23 The hyperextension required to keep the tail out of the surgical field when cats are placed in ventral recumbency can lead to damage to the lumbosacral and sacral plexus, causing clinical signs similar to a tail pull injury, which has been shown to cause urinary tract dysfunction. 23 Slunsky et al concluded that performing PU in dorsal recumbency is superior to ventral recumbency. 23
This retrospective evaluation of cats having a PU in dorsal recumbency reports minimal short- and long-term minor complications and no major complications. Of the clients who responded to our questionnaire, all were satisfied with their pet’s outcome and reported good-to-excellent quality of life for their cat, which is similar to previous findings of 94% owner satisfaction and 88–89% good quality of life.2,4
Limitations of note include this study’s retrospective nature, which leads to biased case selection and lack of uniform follow-up in all cases. Long-term follow-up was not available for all cats included in this study. Urinalysis or urine culture was not performed routinely after the PU making potential occult UTIs possibly under-reported. Asymptomatic UTI has been reported in cats that have had a PU, so the recurrence rate may be higher than reported here. 20 A small number of cases were included in this study, which can affect the complication rates reported. Evaluation of follow-up was conducted through the use of a previously used client survey; to our knowledge, a validated questionnaire has not been developed. 5
PU is a procedure used to aide in the management of recurrent urethral obstruction in male cats. The goal is to reduce the rate of potentially fatal recurrent urethral obstruction, which is typically secondary to lower urinary tract blockage. The procedure is considered a salvage procedure and is not without complication. It is often reserved for life-threatening obstruction or recurrence. The most commonly reported complications include recurrence of FLUTD and stricture.2,4 Although minor complication rates may be high, many cats go on to have good long-term quality of life.2,4
Conclusions
We have demonstrated that performing PU in dorsal recumbency has potential benefits of decreased incidence of major long-term complications such as urethral stricture formation, and we propose this is due to better visualization for dissection and tissue apposition; however, a randomized prospective study is needed for a direct comparison of PU performed in ventral and dorsal recumbency.
Footnotes
Conflict of interest
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
