Perineal urethrostomy is performed in male cats to relieve and prevent recurrence of urethral obstruction. A surgeon creates an opening from the pelvic portion of the urethra to the perineal skin and amputates the penile portion of the urethra. Perineal urethrostomy is indicated in cats with recurrent urethral obstructions, urethral obstruction that cannot be alleviated through urethral catheterization and retrograde urohydropropulsion, and other causes of urethral narrowing, including strictures, trauma, and neoplasia.1
Several techniques and modifications for PU, including one of patient positioning in dorsal rather than sternal recumbency, have been described.2,3 Surgeons who prefer the dorsal position believe it is more ergonomic for the surgeon, negates the need for repositioning of the patient from sternal to dorsal recumbency if a cystotomy is also necessary during the same anesthetic event, minimizes pressure on the diaphragm by the abdominal viscera so that breathing is not compromised, and avoids cranial movement of the urinary bladder that could inadequately expose the pelvic portion of the urethra for surgical manipulation.3–5 Investigators of a recent study6 involving cat cadavers reported that dorsal recumbency may also be superior to sternal recumbency for patient positioning during PU because the sagittal diameter of the lumbosacral and sacrococcygeal segments of the vertebral canal is not as reduced; therefore, the dorsal position may reduce the likelihood of compression of associated spinal nerves and subsequent nerve injury. The dorsal position may also be associated with a low rate of complications. Investigators of another recent study7 reported that of 12 cats positioned in dorsal recumbency for PU, only 2 had dysuria < 1 month after PU, and 3 of 9 had a single occurrence of a urinary tract infection > 1 month after PU. However, those investigators did not include cats positioned in sternal recumbency. To our knowledge, optimal patient position—sternal or dorsal recumbency—has not yet been evaluated.
Therefore, the primary aim of the retrospective study reported here was to compare the durations of surgery and anesthesia and the likelihoods of short- and long-term postoperative complications between groups of cats in which PU was performed with cats positioned in sternal or dorsal recumbency. We hypothesized that the 2 patient positions would have similar likelihoods of postoperative complications, but that patient position would be associated with durations of surgery and anesthesia in situations in which a cystotomy was necessary. The secondary aim was to compare the complication rates associated with various suture materials (type and size) and skin closure patterns, with the null hypothesis being that complication rates would not significantly differ.
Materials and Methods
Case selection criteria
Cats that underwent PU performed by board-certified veterinary surgeons or small animal surgery residents between January 2004 and December 2015 at 6 veterinary teaching hospitals and 1 private veterinary referral hospital were included in the study. Cats were excluded from the study and, therefore, all analyses if their medical records lacked 2 or more of the following: patient position (sternal or dorsal recumbency), duration of surgery and anesthesia, and documentation of complications.
Medical records review
From the medical record, data were collected regarding patient signalment; body weight; diet fed and medications administered; presenting complaint; indication for PU, including the recurrence of urethral obstruction despite previous PU; patient position for PU and any change in positioning during the same anesthetic event; durations of surgery and anesthesia; concurrent surgical procedures; type and size of suture material; and surgical site closure pattern. If a cat was repositioned during the same anesthetic event, the position in which the PU was performed was recorded as its position for statistical analysis. Data collected pertaining to the postoperative period were the number of days to hospital discharge, the presence and type of short-term complications (defined as complications occurring ≤ 2 weeks after surgery), and the presence and type of long-term complications (defined as complications occurring > 2 weeks after surgery). Dates of surgical revision were also collected, when available. When data were missing for certain variables for a given cat, the cat was excluded from specified analyses concerning those data.
Statistical analysis
For categorical data when expected counts were < 5, the Fisher exact test was used to compare data between the 2 patient positions (sternal recumbency and dorsal recumbency), 2 closure patterns (simple continuous and simple interrupted), 2 suture types (absorbable and nonabsorbable or poliglecaprone 25a and polydioxanoneb), and 3 suture sizes (3-0, 4-0, and 5-0). For categorical data with expected counts > 5, the χ2 test was used. Continuous data were compared between patient positions with the Wilcoxon rank sum test.
For the 4 dependent variables (outcomes) of primary interest, durations of surgery and anesthesia and likelihoods of short- and long-term complications, 18 possible confounding continuous (age and body weight) and categorical (breed [mixed or purebred], sex, presenting complaints [urethral obstruction, frequent posturing to urinate, hematuria, vocalization, urethral tear, nonspecific abnormal behavior, vomiting, pollakiuria, urethral trauma, urethral stricture, and urolithiasis], patient position [sternal or dorsal recumbency], and year of surgery) variables were considered as independent variables. Appropriate univariable statistical tests (ie, Wilcoxon rank sum, χ2, and Fisher exact tests and linear regression) were used to determine whether any of these 18 independent variables were associated with 1 or more of the 4 outcomes of primary interest. All variables that were associated with any of the outcomes of interest with a value of P < 0.20 were included in a multivariable linear regression model for durations of surgery and anesthesia or in a multivariable logistic regression model for likelihoods of short- and long-term complications. Independent variables other than patient position that were included in each of the multivariable models were sequentially evaluated and retained in the models if the P value was < 0.20. However, patient position was retained in each of the multivariable models regardless of the P value. All independent variables that were not included in the penultimate multivariable models were then individually included and subsequently retained in the respective model if the P value was < 0.20. The final multivariable models included all independent variables with values of P < 0.20, plus patient position. The variance inflation factor was < 2.0 for all independent variables in all models. Values of P < 0.05 were considered significant.
Results
Cats
Of the 247 cats included in the study, 163 (66%) were positioned in sternal recumbency, and 76 (30.8%) were positioned in dorsal recumbency; position was not recorded for 8 (3.2%; Table 1). Age, body weight, sex, breed, and indications for PU were not significantly different between cats positioned in sternal recumbency and cats positioned in dorsal recumbency.
Comparisons of age, body weight, sex, and breed between groups of cats positioned in sternal or dorsal recumbency for PU at 6 veterinary teaching hospitals and 1 private veterinary referral hospital between January 2004 and December 2015.
| Characteristic | Sternal recumbency (n = 163) | Dorsal recumbency (n = 76) | P value |
|---|---|---|---|
| Age (y) | 5.8 (3−8.5) | 5.8 (3−8) | 0.97 |
| Body weight (kg) | 5.7 (4.8–6.5) | 5.9 (4.9–6.8) | 0.28 |
| Sex | 0.44 | ||
| Neutered male | 156 (95.7) | 72 (94.7) | |
| Sexually intact male | 7 (4.3) | 3 (4.0) | |
| Spayed female | 0 (0.0) | 1 (1.3) | |
| Breed | 0.60 | ||
| Mixed | 142 (87.1) | 68 (89.5) | |
| Pure | 21 (12.9) | 8 (10.5) |
Values for age and body weight represent the median (interquartile [25th to 75th percentile] range), and those for sex and breed represent the number (%) with the indicated characteristic.
Indications for PU
Urethral obstruction was the most common indication for PU (207/239 [86.6%]). Less common indications were a failed attempt at urethral catheterization to alleviate a urethral obstruction or urethral reobstruction after removal of an indwelling urinary catheter (24/239 [10%]) and the presence of a urethral stricture (14/239 [5.9%]).
Significantly (P = 0.02) more cats that were straining or frequently posturing to urinate were positioned in sternal recumbency for PU, whereas all cats that had urethral tears or ruptures were positioned in dorsal recumbency (P < 0.001; Table 2). Most cats with a history of urethral obstruction (63/68 [92.6%]) had ≥ 2 (range, 1 to 5) previous obstructions prior to the study PU procedure. Sixteen of 247 (6.5%) cats previously had a PU performed elsewhere. Of these 16 cats, data available for 12 cats indicated a mean ± SD time of 3 ± 2 months prior to the PU that qualified them for this study.
Number (%) of cats in Table 1 with various presenting complaints.
| Complaint | All cats (n = 239) | Sternal recumbency (n = 163) | Dorsal recumbency (n = 76) | P value |
|---|---|---|---|---|
| Urethral obstruction | 143 (59.8) | 92 (56.4) | 51 (67.1) | 0.12 |
| Straining or frequent posturing to urinate | 47 (19.7) | 39 (23.9) | 8 (10.5) | 0.02 |
| Nonspecific abnormal behavior | 29 (12.1) | 22 (13.5) | 7 (9.2) | 0.34 |
| Pollakiuria | 21 (8.8) | 17 (10.4) | 4 (5.3) | 0.19 |
| Vocalization | 13 (5.4) | 9 (5.5) | 4 (5.3) | > 0.99 |
| Vomiting | 11 (4.6) | 9 (5.5) | 2 (2.6) | 0.51 |
| Urethral stricture | 10 (4.2) | 5 (3.1) | 5 (6.6) | 0.30 |
| Urolithiasis | 10 (4.2) | 5 (3.1) | 5 (6.6) | 0.30 |
| Hematuria | 7 (2.9) | 4 (2.5) | 3 (4.0) | 0.68 |
| Urethral tear or rupture | 6 (2.5) | 0 (0.0) | 6 (7.9) | < 0.001 |
| Trauma | 3 (1.3) | 1 (0.6) | 2 (2.6) | 0.24 |
PU procedure
A cystotomy was performed during the same anesthetic event as that for the PU for 25 of 247 (10.1%) cats. Six of 163 (3.7%) cats that were positioned in sternal recumbency had to be repositioned to dorsal recumbency because of the need for a cystotomy (3/6) or prepubic urethrostomy (3/6). Prepubic urethrostomy was necessary for these 3 cats because of a urethral stricture and trauma proximal to the bulbourethral glands (2 cats) or inadequate urethral tissue for surgical manipulation to attempt a second PU (ie, had a previous PU prior to evaluation; 1 cat).
The suture pattern used for surgical closure of the urethrostomy site (skin incision) was known for 237 cats. A continuous suture pattern was used in 125 (52.7%) cats, and a simple interrupted pattern was used in 112 (47.3%) cats. The type of suture material used for surgical closure was known for 241 cats; absorbable suture material was used in 194 (80.5%) cats, and nonabsorbable suture material was used in 47 (19.5%) cats.
Durations of surgery and anesthesia for PU or PU plus cystotomy for cats that were positioned in sternal recumbency did not significantly differ from those for cats that were positioned in dorsal recumbency (surgery: P = 0.99 and 0.64, respectively; anesthesia: P = 0.49 and 0.46, respectively; Figure 1). In the multivariable linear regression model, patient position had no association with duration of surgery (P = 0.48; Table 3) or anesthesia (P = 0.37; Table 4). Concurrent cystotomy (vs no cystotomy) was associated with a 46.6-minute increase in the duration of surgery (95% CI, 29.2 to 64.0 minutes; P < 0.001) and a 48.9-minute increase in the duration of anesthesia (95% CI, 26.0 to 71.9 minutes; P < 0.001). Each subsequent year of surgery over the study period was associated with a 1.4-minute increase in the duration of surgery (95% CI, 0.1 to 2.7 minutes; P = 0.04) and a 2.5-minute increase in the duration of anesthesia (95% CI, 0.8 to 4.2 minutes; P = 0.004). A presenting complaint of urethral tear or rupture was associated with a 43.9-minute decrease in the duration of anesthesia (95% CI, −83.4 to −4.2; P = 0.03).
Mean durations of surgery and anesthesia for PU (n = 195) or PU plus cystotomy (20) for cats positioned in sternal recumbency (154; gray bars) or dorsal recumbency (61; black bars) at 6 veterinary teaching hospitals and 1 private veterinary referral hospital from January 2004 through December 2015. Values did not significantly (P ≥ 0.46) differ between positions.
Citation: Journal of the American Veterinary Medical Association 257, 2; 10.2460/javma.257.2.176
Data from the final multivariable linear regression model to identify factors associated with duration of surgery for the cats of Table 1.
| Variable | Estimate (min) | SE | 95% CI | P value |
|---|---|---|---|---|
| Position (dorsal vs sternal) | 4.5 | 6.32 | −7.9 to 16.9 | 0.48 |
| Cystotomy (yes vs no) | 46.6 | 8.89 | 29.2 to 64.0 | < 0.001 |
| Age (y) | 1.3 | 0.68 | −0.1 to 2.6 | 0.06 |
| Year of surgery | 1.4 | 0.67 | 0.1 to 2.7 | 0.04 |
A positive estimate indicates an increase in the duration of surgery.
Data from the final multivariable linear regression model to identify factors associated with duration of anesthesia for the cats in Table 1.
| Variable | Estimate (min) | SE | 95% CI | P value |
|---|---|---|---|---|
| Presenting complaint (yes vs no) | ||||
| Hematuria | −34.9 | 19.8 | −73.8 to 3.9 | 0.08 |
| Urethral tear or rupture | −43.9 | 20.2 | −83.5 to −4.2 | 0.03 |
| Vomiting | 24.1 | 14.3 | −3.9 to 52.2 | 0.09 |
| Urolithiasis | 26.2 | 14.7 | −2.7 to 55.0 | 0.08 |
| Position (dorsal vs sternal) | 7.5 | 8.2 | −8.7 to 23.6 | 0.37 |
| Cystotomy (yes vs no) | 48.9 | 11.7 | 26.0 to 71.9 | < 0.001 |
| Year of surgery | 2.5 | 0.9 | 0.8 to 4.2 | 0.004 |
A positive estimate indicates an increase in the duration of anesthesia. A negative estimate indicates a decrease in the duration of anesthesia.
Complications
The overall short-term and long-term complication rates were 47.3% (113/239) and 27.2% (65/239), respectively. Signs of FLUTD (eg, stranguria, pollakiuria, dysuria, and periuria; n = 58 [24.3%]), hematuria (35 [14.6%]), and peristomal irritation or undesirable granulation tissue (18 [7.5%]) were the most common short-term (≤ 2 weeks after PU) complications. Less common short-term complications were urinary tract infection (14 [5.9%]), urinary or fecal incontinence (6 [2.5%]), anorexia (5 [2.1%]), cardiopulmonary arrest (5 [2.1%]), anemia (4 [1.7%]), surgical site dehiscence (4 [1.7%]), uroabdomen (4 [1.7%]), pyrexia (4 [1.7%]), urine leakage at the surgical site (2 [0.8%]), and other unspecified complications (15 [6.3%]). Urinary tract infection (n = 38 [15.9%]), hematuria (31 [13%]), and recurrent urolithiasis (15 [6.3%]) were the most common long-term (> 2 weeks after PU) complications. Less common long-term complications were peristomal irritation or undesirable granulation tissue (11 [4.6%]), need for surgical revision (9 [3.8%]), urethral stricture (6 [2.5%]), urinary or fecal incontinence (4 [1.7%]), excessive licking of the surgical site (3 [1.2%]), peristomal or stomal necrosis (2 [0.8%]), urine marking (1 [0.4%]), acute-on-chronic kidney disease (1 [0.4%]), intermittent dysuria (1 [0.4%]), dehiscence of abdominal incision and intestinal entrapment (1 [0.4%]), rectourethral fistula (1 [0.4%]), urethral tear and uroabdomen (1 [0.4%]), urine scalding (1 [0.4%]), regrowth of hair within the stoma and peristomal discharge (1 [0.4%]), ureteral obstruction with ureterolith (1 [0.4%]), and diarrhea and constipation (1 [0.4%]). Patient position was not associated with the likelihood of short- or long-term complications in the multivariable logistic regression models (P = 0.79 and 0.31, respectively; Tables 5 and 6). However, a presenting complaint of vocalization (vs no vocalization) was associated with an increased likelihood of long-term complications (OR, 3.53; 95% CI, 1.01 to 12.37; P = 0.049), and each subsequent year of surgery was associated with a 10% decrease in the likelihood of long-term complications (OR, 0.90; 95% CI, 0.82 to 0.98; P = 0.02).
Data from the final multivariable logistic regression model to identify factors associated with the likelihood of short-term complications for the cats in Table 1.
| Variable | OR | 95% CI | P value |
|---|---|---|---|
| Neutered male (yes vs no) | 0.32 | 0.08–1.26 | 0.10 |
| Presenting complaint | |||
| Urethral obstruction (yes vs no) | 0.54 | 0.29–1.02 | 0.06 |
| Positioning (dorsal vs sternal) | 0.91 | 0.45–1.83 | 0.79 |
| Body weight | 1.14 | 0.95–1.36 | 0.16 |
Data from the final multivariable logistic regression model to identify factors associated with the likelihood of long-term complications for the cats in Table 1.
| Variable | OR | 95% CI | P value |
|---|---|---|---|
| Presenting complaint (yes vs no) | |||
| Urethral obstruction | 0.52 | 0.26–1.04 | 0.06 |
| Vocalization | 3.53 | 1.01–12.37 | 0.049 |
| Urethral tear or rupture | 0.14 | 0.01–1.54 | 0.11 |
| Positioning (dorsal vs sternal) | 1.51 | 0.69–3.30 | 0.31 |
| Year of surgery | 0.90 | 0.82–0.98 | 0.02 |
For those cats in which a simple continuous (vs simple interrupted) suture pattern was used, hematuria was more common as a short-term and long-term complication (P = 0.004 and 0.02, respectively), and recurrent signs of FLUTD were more common as a short-term complication (P = 0.001). Absorbable (vs nonabsorbable) suture material was associated with recurrent signs of FLUTD in the short-term period (P = 0.01) and with urinary tract infection in the long-term period (P = 0.005). No significant difference in the likelihood of short- or long-term complications was noted between absorbable suture materials poliglecaprone 25a and polydioxanone.b The most frequently used suture sizes were 4-0 (164/230 [71.3%]), 5-0 (56/230 [24.3%]), and 3-0 (10/230 [4.3%]). No significant differences in complication rates were identified among suture sizes.
Discussion
The primary goal of the present study was to determine whether patient position (sternal or dorsal recumbency) for PU in cats was associated with the durations of surgery and anesthesia and the likelihoods of short- and long-term complications. No significant differences in durations of surgery and anesthesia were identified for PU alone or in combination with cystotomy between cats positioned in sternal recumbency and those positioned in dorsal recumbency. The lack of significant differences was most likely attributable to preplanning by the surgeon to perform both PU and cystotomy during the same anesthetic event, regardless of whether a patient required a position change from sternal to dorsal recumbency. Indeed, in our study, 3.7% of cats that were positioned in sternal recumbency had to be repositioned to dorsal recumbency because of the need for a cystotomy or prepubic urethrostomy rather than a PU, and such repositioning was not associated with a significant increase in the durations of surgery and anesthesia, compared with the durations for cats that did not have to be repositioned (ie, patient position—sternal or dorsal recumbency—was not associated with durations of surgery and anesthesia despite the need for some cats to be repositioned).
Short- and long-term complications of PU reported for the present study were similar to those reported previously,8–16 with recurrence of signs of FLUTD and hematuria as the most common short-term complications and urinary tract infection and hematuria as the most common long-term complications for the cats. Hematuria was classified as a complication independent of FLUTD because perioperative hemorrhage is a common complication of PU.1,9,17 Urethral stricture was a long-term complication in 2.5% of cats, which supported findings of other studies8,12 that indicated urethral stricture to be an uncommon long-term complication. Although these complications may have been associated with PU, they may also have been associated with underlying disease, such as idiopathic cystitis. Idiopathic cystitis will induce hematuria and signs of FLUTD that are indistinguishable from those of complications of PU.8,15 Importantly, however, patient position was not associated with the likelihood of postoperative complications in the present study.
Factors that may have contributed to the urinary tract infections in cats that underwent PU include an underlying uropathy, trauma secondary to urethral catheterization, and alterations of the urinary tract's intrinsic defenses against infection.8,9,12–14 Slunsky et al6 identified a significantly greater reduction in the sagittal diameters of a greater number of lumbar, sacral, and sacrococcygeal segments of the vertebral canal in cat cadavers when they were placed in sternal versus dorsal recumbency. Such reduction may compress associated nerves, leading to dysfunction of the anal sphincter and the urinary bladder, and dysfunction may then predispose the urinary tract to infection. Yet, in the present study of live cats, patient position was not associated with the likelihood of postoperative complications, including those that could have been attributed to nerve injury (ie, urinary tract infections and fecal or urinary incontinence).
Most cats (163/247 [66%]) in our study were positioned in sternal recumbency. Each surgeon likely preferred one position over another; therefore, the preferred position was likely selected unless circumstances warranted otherwise (ie, need for cystotomy or prepubic urethrostomy). This preference was supported by the fact that surgeons at 3 of the 7 study sites performed 84% of PUs with cats positioned in dorsal recumbency (data not shown). The distribution of cats and their associated position—sternal or dorsal recumbency—for PU differed significantly between the 7 study sites, and this difference could have influenced our findings. We did not perform an a priori sample size calculation to ensure that sufficient cats were included to minimize the chance of a type II error. Therefore, our study may have had insufficient power to identify significant differences in the durations of surgery and anesthesia and in the likelihoods of short- and long-term complications between cats positioned in sternal recumbency and those positioned in dorsal recumbency if such differences were truly present.
Signalment, presenting complaints, and indications for PU were comparable to those previously described.8,10–12 Interestingly, all 6 cats of the present study that had a urethral tear or rupture were positioned in dorsal recumbency. Surgeons may have opted to position these cats in dorsal recumbency because surgeons could then quickly adjust to a prepubic urethrostomy or because they could perform a cystotomy as necessary to pass a catheter in a normograde direction from the urinary bladder into the urethra. Indeed, urethral tears or ruptures that pertained solely to cats positioned in dorsal recumbency were associated with a decrease in the duration of anesthesia by 43.9 minutes. A presenting complaint of vocalization, recorded for 13 of 239 (5.4%) cats, was significantly associated with the likelihood of long-term complications in our multivariable logistic regression model. A possible explanation for this association is the variation among cats in their expression of discomfort or stress.18 Many of the long-term complications reported in our study were likely associated with discomfort, and possibly some cats that were accustomed to communicating with their owners (ie, to vocalize to gain the owner's attention) did so because of discomfort associated with the urinary tract.19 Additionally, each subsequent year of surgery over the study period was associated with a decreased likelihood of long-term complications. This may have been because of year-over-year improved understanding of FLUTD and implementation of evidence-based medical and behavioral strategies for the long-term management of cats with FLUTD.20
In the present study, we identified that a simple continuous (vs simple interrupted) suture pattern was associated with hematuria and recurrence of signs of FLUTD in the short term and with hematuria in the long term. To our knowledge, a comparison of suture patterns for skin closure for PU in cats has not been reported previously. Additionally, we identified that absorbable (vs nonabsorbable) suture material was associated with signs of FLUTD in the short term and with urinary tract infections in the long term. The latter finding is inconsistent with the findings of Agrodnia et al,21 who reported no differences in complication rates between PU procedures in which absorbable suture material was used in a simple continuous pattern and those in which nonabsorbable suture material was used in a simple interrupted or simple continuous pattern. A difference may have been noted in our study because of the larger sample size (39 cats in the previous study21 vs 237 cats in the present study). However, confounding variables may also account for this difference. Multivariable logistic regression analysis, as performed to identify any association between patient position and durations of surgery and anesthesia and likelihoods of short- and long-term complications, was not performed to identify any association between suture pattern or type and likelihoods of short- and long-term complications because of the large number of confounding variables. Additional research is needed to investigate potential associations between suture pattern and type and likelihoods of short- and long-term complications.
Fortunately, many of the types of short- and long-term complications observed in cats after PU in the present study can be mitigated or resolved medically. The investigators of 2 previous retrospective studies8,11 involving cats that underwent PU reported that the postoperative recurrence of urethral obstruction was low and client-perceived quality of life was good. Although the rate of urethral obstruction was not specifically evaluated, conditions that could have caused obstruction (eg, urethral stricture) in the cats of the present study were similarly low.
In the present study, cat position for PU was not associated with the durations of surgery and anesthesia, even with concurrent cystotomy or repositioning from sternal recumbency to dorsal recumbency for some cats. Likewise, patient position was not associated with the likelihoods of short- and long-term complications. Therefore, logistic considerations (eg, need for cystotomy) and personal preference may continue to guide veterinarians when positioning cats for PU.
Acknowledgments
Supported by a grant from the Phi Zeta Honor Society at the University of Missouri College of Veterinary Medicine.
The authors declare there were no conflicts of interest.
Presented in abstract form online at the 19th Annual Scientific Meeting of the Society of Veterinary Soft Tissue Surgery, June 2020.
The authors thank Dr. Joe Hauptman for providing statistical analysis and Taylor Graville for data collection.
ABBREVIATIONS
| FLUTD | Feline lower urinary tract disease |
| PU | Perineal urethrostomy |
References
1. Smith CW. Perineal urethrostomy. Vet Clin North Am Small Anim Pract 2002;32:917–925.
2. Wilson GP III, Harrison JW. Perineal urethrostomy in cats. J Am Vet Med Assoc 1971;159:1789–1793.
3. Kagan KG, Stewart RW, Leighton RL. Perineal urethrostomy in male cats. Mod Vet Pract 1976;57:187–191.
4. Goh CSS, Seim HB III. Feline perineal urethrostomy ventral approach. Todays Vet Pract 2014;4(4):43–49.
5. Tobias KM. Perineal urethrostomy in the cat. Clin Brief 2007;5:19–22.
6. Slunsky P, Brunnberg M, Lodersted S, et al. Effect of intraoperative positioning on the diameter of the vertebral canal in cats during perineal urethrostomy (cadaveric study). J Feline Med Surg 2018;20:38–44.
7. Watson MT, Roca RY, Breiteneicher AH, et al. Evaluation of postoperative complication rates in cats undergoing perineal urethrostomy performed in dorsal recumbency. J Feline Med Surg 2020;22:399–403.
8. Bass M, Howard J, Gerber B, et al. Retrospective study of indications for and outcome of perineal urethrostomy in cats. J Small Anim Pract 2005;46:227–231.
9. Gregory C, Vasseur P. Long-term examination of cats with perineal urethrostomy. Vet Surg 1983;12:210–212.
10. Griffin DW, Gregory CR. Prevalence of bacterial urinary tract infection after perineal urethrostomy in cats. J Am Vet Med Assoc 1992;200:681–684.
11. Ruda L, Heiene R. Short- and long-term outcome after perineal urethrostomy in 86 cats with feline lower urinary tract disease. J Small Anim Pract 2012;53:693–698.
12. Corgozinho KB, de Souza HJ, Pereira AN, et al. Catheter-induced urethral trauma in cats with urethral obstruction. J Feline Med Surg 2007;9:481–486.
13. Smith C, Schiller A. Perineal urethrostomy in the cat: a retrospective study of complications. J Am Anim Hosp Assoc 1978;14:225–228.
14. Gregory CR, Vasseur PB. Electromyographic and urethral pressure profilometry: long-term assessment of urethral function after perineal urethrostomy in cats. Am J Vet Res 1984;45:1318–1321.
15. Osborne C, Caywood D, Johnston G, et al. Perineal urethrostomy versus dietary management in prevention of recurrent lower urinary tract disease. J Small Anim Pract 1991;32:296–305.
16. Johnson MS, Gourley I. Perineal hernia in a cat: a possible complication of perineal urethrostomy. Vet Med Small Anim Clin 1980;75:241–243.
17. Hauptman J. Perineal urethrostomy: surgical technique and management of complications. Vet Clin North Am Small Anim Pract 1984;14:93–102.
18. Urrutia A, Martínez-Byer S, Szenczi P, et al. Stable individual differences in vocalisation and motor activity during acute stress in the domestic cat. Behav Processes 2019;165:58–65.
19. Tavernier C, Ahmed S, Houpt KA, et al. Feline vocal communication. J Vet Sci 2020;21:e18.
20. Forrester SD, Roudebush P. Evidence-based management of feline lower urinary tract disease. Vet Clin North Am Small Anim Pract 2007;37:533–558.
21. Agrodnia MD, Hauptman JG, Stanley BJ, et al. A simple continuous pattern using absorbable suture for perineal urethrostomy in the cat: 18 cases (2000–2002). J Am Anim Hosp Assoc 2004;40:479–483.
