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Treatment of Lower Urinary Tract Obstruction via Scrotal Urethrostomy in an Eastern Fox Squirrel (Sciurus niger)
Author’s Accepted Manuscript TREATMENT OF LOWER URINARY TRACT OBSTRUCTION VIA SCROTAL URETHROSTOMY IN AN EASTERN FOX SQUIRREL (SCIURUS NIGER) Laura Kleinschmidt, Mark Stickney, Sharman Hoppes www.sasjournal.com
PII: DOI: Reference:
S1557-5063(16)30080-5 http://dx.doi.org/10.1053/j.jepm.2016.06.007 JEPM683
To appear in: Journal of Exotic Pet Medicine Cite this article as: Laura Kleinschmidt, Mark Stickney and Sharman Hoppes, TREATMENT OF LOWER URINARY TRACT OBSTRUCTION VIA SCROTAL URETHROSTOMY IN AN EASTERN FOX SQUIRREL (SCIURUS NIGER) , Journal of Exotic Pet Medicine, http://dx.doi.org/10.1053/j.jepm.2016.06.007 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
AEMV Forum
Treatment of Lower Urinary Tract Obstruction via Scrotal Urethrostomy in an Eastern Fox Squirrel (Sciurus niger) Laura Kleinschmidt, DVM, Mark Stickney, DVM, and Sharman Hoppes, DVM, Dip. ABVP (Avian) From Texas A&M University, College of Veterinary Medicine and Clinical Sciences, Department of Small Animal Clinical Sciences, College Station, Texas, USA Please address correspondence to Laura Kleinschmidt, DVM, One Government Drive, Saint Louis, MO 63110 USA. Email address: [email protected], Tel: 314-646-4724
Abstract A 2 year old castrated male Eastern fox squirrel (Sciurus niger) presented with a 3-4 week history of stranguria and intermittent lower urinary tract obstruction. A complete blood count, serum chemistry analysis, urinalysis, urine culture, radiographic imaging and ultrasonography helped formulate a diagnosis of severe chronic cystitis-induced lower urinary tract obstruction. The patient was treated using a pigtail drainage catheter followed by scrotal urethrostomy and abdominal exploratory surgery. Lower urinary tract disease and obstruction can occur sporadically in rodent species, resulting in presentation for hematuria, stranguria, decreased appetite, and lethargy. When complete obstruction occurs, urinary catheterization and/or surgical intervention are warranted. This case report demonstrates the use of scrotal urethrostomy for treatment of complicated lower urinary tract obstruction in a rodent species. Key words: Scrotal urethrostomy; Eastern fox squirrel; Sciurus niger; lower urinary tract obstruction; chronic cystitis; lower urinary tract disease
A 2-year-old castrated male Eastern fox squirrel (Sciurus niger) presented to Texas A&M University Small Animal Clinical Sciences Zoological Medicine Service (TAMU) with a 4 week history of stranguria and intermittent lower urinary tract obstruction. The patient had been hand-raised by its owners after being found as a neonate. The animal was unable to use its forelimbs properly due to an anatomic abnormality (distal forelimbs permanently supinated). The squirrel lived in a 3' x 4' chinchilla cage with hammocks and swings, but was allowed to roam free in the house under supervision during the day and interacted with the owner's cat, which was apparently healthy. The animal’s diet was a commercial rat food diet supplemented with a variety of seeds, nuts, grapes, and apples. At the onset of stranguria, the owners administered a single dose of ceftiofur crystalline free acid (unknown product information, dosage or route), and stimulated the squirrel to urinate manually using a warm wet washcloth for one week. The patient was then presented to the referring veterinarian who noted a firm bladder that could not be expressed upon palpation. Apparent urinary obstruction was resolved via catheterization with a tomcat catheter (unknown size), although per the owner, catheterization was very difficult. Urine appeared grossly normal. The patient was given an injection of Meloxicam (unknown product information or dosage), but no additional medications were administered or prescribed. The owners continued to intermittently manually stimulate the squirrel to urinate, and the patient became progressively lethargic with decreasing appetite. When the squirrel was reexamined by the referring DVM, he was complete anorexic and had not urinated for 2-3 days. A severely distended bladder was palpable and thirty-five milliliters of bloody urine was
removed from the bladder via cystocentesis. The patient was then referred to TAMU for further evaluation and treatment. On physical exam, the patient was bright, alert, and responsive, and his temperature, pulse, and respiration were within normal limits. The patient weighed 716 grams with a body condition score of four out of five. The patient was estimated to be 10% dehydrated. No musculoskeletal abnormalities were noted on palpation of the limbs, however the distal forelimbs were held in a supinated position. Abdominal palpation revealed a moderately distended urinary bladder and a tense, painful abdomen. The prepuce appeared erythematous. No other abnormalities were noted. The patient was sedated with midazolam (0.5 mg/kg subcutaneous, Midazolam Hydrochloride, 5 mg/ml Injection; West-ward, Eatontown, NJ USA) and maintained on sevoflurane (SevoFlo; Abbott Laboratories, North Chicago, IL USA) via face mask for the duration of the diagnostic evaluation and collection of diagnostic test samples. The patient’s complete blood cell count and serum chemistry panel were within normal limits. Abdominal radiographs revealed severe distension of the urinary bladder causing cranial displacement of the abdominal organs (Figs. 1 and 2). The intestinal tract contained heterogenous soft tissue opaque material and gas with several mildly gasdistended small intestinal segments. The radiographic diagnosis was consistent with lower urinary tract obstruction including possible functional ileus. Abdominal ultrasonography was performed on the squirrel and revealed a markedly distended urinary bladder with gravity dependent sediment. There were multiple hyperechoic shadowing foci (suspected sediment) within the trigonal region. The urinary bladder wall was hyperechoic, thickened and mildly irregular. There was a
focal thickening along the wall that may have been associated with a prior cystocentesis or wall leakage. A small amount of gas was present in the bladder. While kidney size was considered normal while there appeared to be mild bilateral dilation affecting the renal pelvises and proximal ureters. There was a small echogenic structure at the distal extent of the urethra at the tip of the penis. In the absence of urethral dilatation, the echogenic structure at the distal urethra was not thought to be an obstructing calculus. The fat around the bladder was adhered to the bladder wall and was hyperechoic. There was a small amount of fluid in the peritoneal cavity. Cystocentesis was performed on the distended urinary bladder during the ultrasound procedure. Sonographic diagnoses included mild peritoneal fluid, possibly associated with previous cystocentesis, a rupture site of the bladder, and/or translocation of inflammation from the bladder to the surrounding tissue; probable adhesions and inflammation around the bladder most likely from chronic bladder distension, inflammation, or rupture; cystitis; possible fine urethral calculi or sediment, and mild bilateral renal and ureteral dilation consistent with a history of urethral obstruction. Gas in the bladder was thought to be iatrogenic. The urine sample obtained by sonographic-guided cystocentesis was submitted for urinalysis and culture. The patient’s urine contained large amounts of protein and blood, but no other abnormalities were noted. The patient was diagnosed with severe chronic cystitis and urethritis resulting in complete lower urinary tract obstruction
As the owners declined urinary catheterization or other more invasive therapies, in hospital medical management was initiated, and included periodic cystocentesis of the bladder, buprenorphine (0.5 mg/kg subcutaneous, 4 times a day, Buprenex, 0.3 mg/ml Solution; Reckitt Benckiser, Richmond, VA USA), meloxicam (1 mg/kg subcutaneous, once a day, Metacam, 5 mg/ml Injectable Solution; Boehringer Ingelheim, St. Joseph, MO USA), enrofloxacin (20 mg/kg subcutaneous, once a day, Baytril, 22.7 mg/ml solution; Bayer Healthcare LLC, Shawnee Mission, KS USA), and subcutaneous fluids as needed to correct dehydration. The patient did not respond over the first 24 hours of hospitalization and remained completely obstructed. Additional treatment options were offered and included humane euthanasia, urinary catheterization, and/or surgical intervention. The owners elected urinary catheterization. The patient was sedated as above, and anesthesia was maintained with sevoflurane via face mask. Urethral catheterization was unsuccessful despite multiple attempts using a small 3.5 french red rubber catheter (Kendall Urethral Catheter, Covidien LLC, Mansfield, MA USA). The owners then agreed to placement of a pigtail catheter transabdominally into the urinary bladder followed by scrotal urethrostomy surgery the following day, with the possible addition of abdominal exploratory surgery to assess the bladder wall integrity, search for possible urinary calculi, and facilitate retrograde passage of a urinary catheter to assist in scrotal urethrostomy. The abdomen was prepared with standard aseptic technique and a sterile pigtail catheter (Pigtail Drainage Catheter Set, Infiniti Medical LLC, Menlo Park, CA USA) was passed transabdominally into the bladder with ultrasound guidance (Figure 3a-b).1-2 Patency was verified and a closed collection system was attached. An intravenous catheter was
placed in the cephalic vein for intravenous fluid administration and postoperative sedation. The patient was monitored overnight in the intensive care unit (ICU) with a constant rate infusion (CRI) of midazolam at (0.1 mg/kg/hr). Fluid intake, urine production, respiratory rate and heart rate were monitored closely while in the ICU. Lactated Ringer’s solution (Veterinary Lactated Ringer’s Injection USP, Abbott Laboratories, North Chicago, IL USA) was infused at 3 ml/hr intravenous. Buprenorphine, meloxicam, and enrofloxacin were continued following the placement of the pigtail catheter. Overnight, urinary output decreased and it was suspected that the pigtail catheter was no longer in the urinary bladder and/or that it was associated with bladder rupture. The squirrel was taken to surgery for abdominal exploratory and scrotal urethrostomy. The patient was adequately sedated from the midazolam CRI and pain appeared well controlled with buprenorphine and meloxicam. The patient was induced and anesthesia maintained with sevoflurane via face mask. The patient was placed in dorsal recumbency. The abdomen, caudal thigh area, and perineal region were clipped using #40 clipper blades with a proximal margin at the base of the sternum, a distal margin at the level of the base of the tail, and wide lateral margins. A surgical prep was performed using povidone-iodine scrub. The patient was transported to the surgical suite and placed in dorsal recumbency. Tape was used to secure the pelvic limbs in place. A clear sterile drape was placed over the patient. A 3 cm ventral midline incision was made from the umbilicus to just cranial to the prepuce through the skin and subcutaneous tissues as well as the abdominal wall through the linea alba using a #15 scalpel blade (Figure 4a). Upon entering the
abdomen, approximately 10 ml of hemorrhagic fluid was present (suspected hemorrhagic urine). The bladder was examined and a small circular approximately 0.5 cm diameter rupture site was present in the ventral wall parallel to the trigone, suspected to be associated with previous pigtail urinary catheterization. The pigtail urinary catheter had exteriorized from the urinary bladder and thus was removed from the abdomen. Stay sutures were placed in the urinary bladder to facilitate manipulation. A 2 cm elliptical incision was then made surrounding the scrotum using a #15 scalpel blade and scrotal tissue and fat were removed. The incision was extended caudally to expose urethral tissue (Figure 4b). The subcutaneous tissue was undermined using Metzenbaum scissors. Hemostasis was maintained using hemostats and digital pressure with sterile gauze. Along the ventral midline of the distal penile urethra, a small stab incision was made using a #15 blade and extended proximally for 2 cm using tenotomy scissors to expose urethral mucosa. A lubricated 3.5 Fr red rubber catheter was placed through the rupture site in the bladder and fed into the urethra to the created stoma (Figure 4c). Patency of the urethra was confirmed. Using 4-0 poliglecaprone 25 (Monocryl Suture, Ethicon, Guaynabo, Puerto Rico), simple interrupted sutures were placed on both lateral sides of the urethral incision, apposing the urethral mucosa and the skin to create the urethrostomy site (Figure 4d). The red rubber catheter was removed and the bladder was flushed with sterile saline to ensure the patency of the urethrostomy site, which was confirmed. A 2 cm incision into the bladder was made extending from the rupture site and the bladder was explored; no uroliths were found. The bladder wall was significantly thickened and had minimal to no contractility on manipulation. The bladder wall was closed with a simple continuous
pattern using 4-0 poliglecaprone 25. Sterile saline was injected into the bladder to ensure adequate closure. No leakage was observed and lower urinary tract was verified as patent. The abdomen was copiously flushed with warm sterile saline prior to closure. The abdominal wall was closed with 3-0 polydioxanone (PDS*II Polydioxanone Suture, Ethicon, Guaynabo, Puerto Rico) in a simple continuous pattern. The skin was closed with 4-0 poliglecaprone 25 in a subcuticular pattern (Figure 4d). A modified Elizabethan collar (E-collar) was placed to prevent self-mutilation of the surgical sites. The patient was monitored post operatively in ICU and medications were continued as previously described. Twenty-four hours postoperatively, the patient had not produced measurable urine, and subcutaneous edema was noted in the cranial half of the body. When the squirrel’s abdomen was palpated at this time there was no evidence of an enlarged bladder. Lung sounds were diffusely harsh with associated crackles, suggestive of pulmonary edema. Serum chemistry panel results were within normal limits. A single dose of furosemide (1.5 mg/kg subcutaneous, Salix; Intervet International GMBH, Germany) was administered once to assess response of the kidneys and to address suspected pulmonary edema. Intravenous fluids were discontinued. Within two hours of receiving furosemide, the squirrel began to produce urine. Intravenous fluids were replaced with fluids administered subcutaneously, as needed, to maintain hydration and assist in flushing of the urinary bladder. Prazosin (0.07 mg/kg orally, 3 times a day, Prazosin HCl, 1 mg capsules; Mylan Pharmaceutical Inc., Morgantown, WV USA) was also prescribed to help prevent urethral spasm.
Overnight, the patient produced moderate amounts of urine (multiple 4-6 cm diameter urine spots on the patient’s towels). On the second day, the patient began eating regularly, was more energetic, while the subcutaneous edema and abnormal lung sounds resolved. The owners elected to continue care at home, and the patient was discharged with oral enrofloxacin (Baytril, 50 mg/ml oral suspension, compounded by Texas A&M University Small Animal Hospital Pharmacy, College Station, TX USA) (20 mg/kg orally, once a day for 14 days), meloxicam (1 mg/kg orally, once a day for 7 days, Metacam, 1.5 mg/ml oral suspension; Boehringer Ingelheim, St. Joseph, MO USA), buprenorphine (0.03 mg/kg orally, 2 – 3 times a day, as needed for discomfort for 5 days, Buprenex, 0.3 mg/ml solution; Reckitt Benckiser, Richmond, VA USA), and prazosin (0.07 mg/kg orally, 3 times a day for 7 days). The owners were instructed to monitor the squirrel’s urine volume and character carefully, and for straining to urinate. Cage rest in a single-level enclosure was prescribed for two weeks following discharge. The owners were instructed to leave the E-collar in place for 10-14 days until the surgical sites had healed, to prevent self-mutilation. The patient returned two days after discharge for reexamination. The patient was doing well according to the owner which included eating, drinking, defecating, and urinating as when the animal was healthy. On physical examination, the patient was apparently euhydrated, with the abdomen being soft on palpation and bladder small. The urethrostomy site was clean and dry with some mild erythema. The ventral midline incision was intact, clean and dry. Due to owner concerns that the patient was not drinking enough water, 45 mL of Lactated Ringer’s solution were administered subcutaneous, and the owners were provided Lactated Ringer’s solution for at-home
use as needed. Medications and monitoring instructions were continued as described above. At an 11 days following the surgical procedure, the squirrel was doing well, but occasionally produced pink-tinged urine associated with mild straining at the end of the urine stream. The E-collar was not used consistently, and the patient appeared to have removed some of urethrostomy sutures, which was otherwise patent and healing well. The owners were instructed to continue use of the E-collar, and to return for a more substantial diagnostic evaluation, including urinalysis if hematuria continued. At 21 days post-surgery, the patient was doing well at home. The owners had been gently cleaning a small amount of debris from the surgical site, but no abnormalities were noted when examined. The urethrostomy site had significantly contracted by approximately 30-50% (Figure 5). Cage rest was discontinued and the owners were instructed to continue monitoring for any signs of lower urinary tract disease. One year following the procedure, the patient had no recurrence of clinical signs associated with lower urinary tract disease.
DISCUSSION Lower urinary tract disease and obstruction occurs sporadically in rodent species; causes include chronic cystitis due to severe urinary tract infection, urolithiasis, accessory sex gland secretion blockage, bacterial infection and abscessation of the accessory sex glands, urogenital neoplasia, and trauma.3-5 As no specific infectious etiology was identified in this case, obstruction was likely due to idiopathic chronic cystitis and urethritis. Idiopathic cystitis resulting in lower urinary tract obstruction is well
documented in feline patients.6-8 Clinical signs of lower urinary tract disease that often precede complete obstruction include hematuria, stranguria, decreased appetite, and lethargy. These clinical signs may culminate in the complete inability to urinate, which can quickly induce severe depression, electrolyte disturbances, azotemia, and death. An ideal diagnostic database for a rodent with suspect urinary tract infection includes urinalysis and urine culture with bacterial antimicrobial sensitivities prior to treatment, diagnostic imaging to rule out radiopaque urolithiasis, abdominal ultrasound to evaluate the urogenital tract, complete blood cell count, and serum biochemistry profile. Treatment for bacterial urinary tract infection in rodents should consist of appropriate antibiotic therapy. Urinary tract obstruction requires placement of a urinary catheter to relieve obstruction, if possible, and treatment of dehydration, azotemia, and electrolyte imbalances. Other medical and surgical management strategies may be indicated as well. Urethrostomy is most commonly performed in castrated male cats to alleviate recurrent or complicated cases of lower urinary tract obstruction.6-8 Other species in which urethrostomy has been documented include small ruminants, antelope species, camelids, equids, dogs, ferrets, a serval, and non-human primates.9-22 A single case of urethrostomy in a rodent species has been reported; this procedure was performed as a salvage procedure in a male rat with preputial adenocarcinoma and subsequent penile amputation.23 Complications of urethrostomy include anesthetic risk, stricture of the surgical site, recurrent ascending bacterial urinary tract infections, urinary incontinence, extravasation of urine, skin necrosis, and self-mutilation of the surgical site. 8-10 Chronic
lower urinary tract obstruction may also lead to bladder dyssynergia due to overdistension of the bladder and/or acute renal failure; development of these conditions may affect the prognosis for the affected individual. The most significant complications noted in this case were pulmonary and subcutaneous edema, and minor disruption of the suture site post surgery, both of which were managed effectively with careful post-operative management and intervention. Of additional concern was contraction of the urethrostomy site, which was not clinically significant in this case; however, risk of stricture must be a consideration for surgical planning. This case report demonstrates successful use of scrotal urethrostomy in an Eastern fox squirrel with severe chronic cystitis-induced lower urinary tract obstruction. Scrotal urethrostomy may be used as an effective treatment of complicated lower urinary tract obstruction in this species with careful post-operative management.
ACKNOWLEDGMENTS The authors would like to thank all the staff and students at Texas A&M University Veterinary Teaching Hospital who helped provide excellent patient care throughout this case as well as Dr. Anton G. Hoffman, DVM, PhD, Presidential Professor for Teaching Excellence and Clinical Professor, Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, who graciously created the artwork for Figure 3b.
REFERENCES 1. Infiniti Medical LLC. “Products: Drainage Catheters (Locking Loop)”. http://infinitimedical.com/products/drainage-catheters/. Last accessed 4 Feb 2015. 2. Kilby MD, Morris RK: Fetal therapy for the treatment of congenital bladder neck obstruction. Nat Rev Urol 11:412-419, 2014 3. Brown C, Donnelly TM: Disease problems of small rodents, in Quesenberry KE, Carpenter JW (eds): Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery (ed 3). St. Louis, MO, Saunders/Elsevier, pp 354-372, 2012 4. Heatley JJ, Harris MC: Hamsters and gerbils, in Mitchell MA, Tully TN (eds): Manual of Exotic Pet Practice. St. Louis, MO, Saunders/Elsevier, pp 406-432, 2009 5. Richardson VCG: Systems and diseases, in Richardson, VCG (ed): Diseases of Small Domestic Rodents. Oxford, UK, Blackwell Publishing, pp 60-67, 141-167, 217238, 2003 6. McLoughlin MA: Complications of lower urinary tract surgery in small animals. Vet Clin North Am Small Anim Pract 41:889-913, 2011 7. 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 53:693-698, 2012 8. Smith CW: Perineal urethrostomy. Vet Clin North Am Small Anim Pract 32:917-925, 2002 9. Bartlett LW: Ferret soft tissue surgery. Semin Avian Exot Pet 11:221-230, 2002 10. Bilbrey SA, Birchard SJ, Smeak DD: Scrotal urethrostomy: a retrospective review of 38 dogs (1973 through 1988). J Am Anim Hosp Assoc 27:560-564, 1991 11. Campbell BG: Prepubic urethrostomy and placement of a caudal superficial epigastric flap for treatment of a self-mutilation injury in a serval. J Am Vet Med Assoc 222:628-632, 2003 12. Duesterdieck-Zellmer KF, Van Metre DC, Cardenas A, et al: Acquired urethral obstruction in New World camelids: 34 cases (1995-2008). Aust Vet J 92:313-319, 2014 13. Fresno L, Fernandez-Moran J, Fernandez-Bellon H, et al: Complicated urethral rupture and scrotal urethrostomy in a Bongo antelope (Tragelaphus eurycerus isaaci). J Zoo Wildlife Vet 39:464-467, 2008
14. Howarth S, Lucke VM, Pearson H: Squamous cell carcinoma of the equine external genitalia: a review and assessment of penile amputation and urethrostomy as a surgical treatment. Equine Vet J 23:53-58, 1991 15. Mutlow AG, Mauch WD, Carpenter JW, et al: Surgical procedure and postoperative management of a perineal urethrostomy in a chimpanzee (Pan troglodytes). J Zoo Wildlife Med 37:381-386, 2006 16. Ramadan RO, Kock RA, Higgins AJ: Observations on diagnosis and treatment of surgical conditions in the camel. Brit Vet J 142:75-89, 1986 17. Ranen E, Freidman T, Aizenberg I: Perineal urethrostomy in a brown capuchin monkey (Cebus apella). J Zoo Wildlife Vet 37:40-43, 2006 18. Larsen SR, Cebra CK, Wild MA: Diagnosis and treatment of obstructive urolithiasis in a captive rocky mountain wapiti (Cervus elaphus nelsoni). J Zoo Wildlife Med 31:236239, 2000 19. Smeak DD: Urethrotomy and urethrostomy in the dog. Clin Tech Small An P 15:2534, 2000 20. Stone WC, Bjorling DE, Trostle SS, et al: Prepubic urethrostomy for relief of urethral obstruction in a sheep and a goat. J Am Vet Med Assoc 210:939-941, 1997 21. Sullivan K, Freeman S, van Huegten E: Impact of two typs of complete pelleted, wild ungulate feeds and two pelleted feed to hay ratios on the development of urolithogenic compounds in meat goats as a model for giraffes. J Anim Physiol An N 97:566-576, 2013 22. Van Weeren PR, Klein WR, Voorhout G: Urolithiasis in small ruminants: a retrospective evaluation of urethrostomy. Vet Quart 9:76-79, 1987 23. Mentre V: Penile Amputation and urethrostomy in a rat. Exotic DVM 9:17-19, 2007
FIGURE LEGENDS Figure 1: Abdominal radiograph, ventrodorsal projection, demonstrating distended bladder, cranial displacement of other abdominal organs, and lack of radiopaque uroliths associated with urethral obstruction. Note subcutaneous fluid pocket on the animal’s left side. Figure 2: Abdominal radiograph, left lateral projection, demonstrating distended bladder, cranial displacement of other abdominal organs, and lack of radiopaque uroliths associated with urethral obstruction. Note subcutaneous fluid pocket on the animal’s dorsum. Figure 3: a) Pigtail drainage catheter set (Pigtail Drainage Catheter Set, Infiniti Medical LLC, Menlo Park, CA USA). b) Schematic representation of ultrasound(C)-guided placement of a pigtail drainage catheter (A) into the urinary bladder (B) of a patient. Figure 4: Intraoperative photographs of techniques utilized during the scrotal urethrostomy procedure in the Eastern fox squirrel. A) Placement of initial abdominal approach relative to the prepuce and scrotum. B) Exposure of the penile urethra after removal of the scrotum and scrotal tissue as well as bladder exteriorization and passage of red rubber catheter to guide urethral incision placement. C) Blue arrow indicating passage of the red rubber catheter tip at level of initial urethral incision. D) Final appearance of scrotal urethrostomy site and abdominal wall closure prior to recovery.
Figure 5: Final appearance of the scrotal urethrostomy site in the Eastern fox squirrel 21 days following the surgical procedure.
PII: DOI: Reference:
S1557-5063(16)30080-5 http://dx.doi.org/10.1053/j.jepm.2016.06.007 JEPM683
To appear in: Journal of Exotic Pet Medicine Cite this article as: Laura Kleinschmidt, Mark Stickney and Sharman Hoppes, TREATMENT OF LOWER URINARY TRACT OBSTRUCTION VIA SCROTAL URETHROSTOMY IN AN EASTERN FOX SQUIRREL (SCIURUS NIGER) , Journal of Exotic Pet Medicine, http://dx.doi.org/10.1053/j.jepm.2016.06.007 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
AEMV Forum
Treatment of Lower Urinary Tract Obstruction via Scrotal Urethrostomy in an Eastern Fox Squirrel (Sciurus niger) Laura Kleinschmidt, DVM, Mark Stickney, DVM, and Sharman Hoppes, DVM, Dip. ABVP (Avian) From Texas A&M University, College of Veterinary Medicine and Clinical Sciences, Department of Small Animal Clinical Sciences, College Station, Texas, USA Please address correspondence to Laura Kleinschmidt, DVM, One Government Drive, Saint Louis, MO 63110 USA. Email address: [email protected], Tel: 314-646-4724
Abstract A 2 year old castrated male Eastern fox squirrel (Sciurus niger) presented with a 3-4 week history of stranguria and intermittent lower urinary tract obstruction. A complete blood count, serum chemistry analysis, urinalysis, urine culture, radiographic imaging and ultrasonography helped formulate a diagnosis of severe chronic cystitis-induced lower urinary tract obstruction. The patient was treated using a pigtail drainage catheter followed by scrotal urethrostomy and abdominal exploratory surgery. Lower urinary tract disease and obstruction can occur sporadically in rodent species, resulting in presentation for hematuria, stranguria, decreased appetite, and lethargy. When complete obstruction occurs, urinary catheterization and/or surgical intervention are warranted. This case report demonstrates the use of scrotal urethrostomy for treatment of complicated lower urinary tract obstruction in a rodent species. Key words: Scrotal urethrostomy; Eastern fox squirrel; Sciurus niger; lower urinary tract obstruction; chronic cystitis; lower urinary tract disease
A 2-year-old castrated male Eastern fox squirrel (Sciurus niger) presented to Texas A&M University Small Animal Clinical Sciences Zoological Medicine Service (TAMU) with a 4 week history of stranguria and intermittent lower urinary tract obstruction. The patient had been hand-raised by its owners after being found as a neonate. The animal was unable to use its forelimbs properly due to an anatomic abnormality (distal forelimbs permanently supinated). The squirrel lived in a 3' x 4' chinchilla cage with hammocks and swings, but was allowed to roam free in the house under supervision during the day and interacted with the owner's cat, which was apparently healthy. The animal’s diet was a commercial rat food diet supplemented with a variety of seeds, nuts, grapes, and apples. At the onset of stranguria, the owners administered a single dose of ceftiofur crystalline free acid (unknown product information, dosage or route), and stimulated the squirrel to urinate manually using a warm wet washcloth for one week. The patient was then presented to the referring veterinarian who noted a firm bladder that could not be expressed upon palpation. Apparent urinary obstruction was resolved via catheterization with a tomcat catheter (unknown size), although per the owner, catheterization was very difficult. Urine appeared grossly normal. The patient was given an injection of Meloxicam (unknown product information or dosage), but no additional medications were administered or prescribed. The owners continued to intermittently manually stimulate the squirrel to urinate, and the patient became progressively lethargic with decreasing appetite. When the squirrel was reexamined by the referring DVM, he was complete anorexic and had not urinated for 2-3 days. A severely distended bladder was palpable and thirty-five milliliters of bloody urine was
removed from the bladder via cystocentesis. The patient was then referred to TAMU for further evaluation and treatment. On physical exam, the patient was bright, alert, and responsive, and his temperature, pulse, and respiration were within normal limits. The patient weighed 716 grams with a body condition score of four out of five. The patient was estimated to be 10% dehydrated. No musculoskeletal abnormalities were noted on palpation of the limbs, however the distal forelimbs were held in a supinated position. Abdominal palpation revealed a moderately distended urinary bladder and a tense, painful abdomen. The prepuce appeared erythematous. No other abnormalities were noted. The patient was sedated with midazolam (0.5 mg/kg subcutaneous, Midazolam Hydrochloride, 5 mg/ml Injection; West-ward, Eatontown, NJ USA) and maintained on sevoflurane (SevoFlo; Abbott Laboratories, North Chicago, IL USA) via face mask for the duration of the diagnostic evaluation and collection of diagnostic test samples. The patient’s complete blood cell count and serum chemistry panel were within normal limits. Abdominal radiographs revealed severe distension of the urinary bladder causing cranial displacement of the abdominal organs (Figs. 1 and 2). The intestinal tract contained heterogenous soft tissue opaque material and gas with several mildly gasdistended small intestinal segments. The radiographic diagnosis was consistent with lower urinary tract obstruction including possible functional ileus. Abdominal ultrasonography was performed on the squirrel and revealed a markedly distended urinary bladder with gravity dependent sediment. There were multiple hyperechoic shadowing foci (suspected sediment) within the trigonal region. The urinary bladder wall was hyperechoic, thickened and mildly irregular. There was a
focal thickening along the wall that may have been associated with a prior cystocentesis or wall leakage. A small amount of gas was present in the bladder. While kidney size was considered normal while there appeared to be mild bilateral dilation affecting the renal pelvises and proximal ureters. There was a small echogenic structure at the distal extent of the urethra at the tip of the penis. In the absence of urethral dilatation, the echogenic structure at the distal urethra was not thought to be an obstructing calculus. The fat around the bladder was adhered to the bladder wall and was hyperechoic. There was a small amount of fluid in the peritoneal cavity. Cystocentesis was performed on the distended urinary bladder during the ultrasound procedure. Sonographic diagnoses included mild peritoneal fluid, possibly associated with previous cystocentesis, a rupture site of the bladder, and/or translocation of inflammation from the bladder to the surrounding tissue; probable adhesions and inflammation around the bladder most likely from chronic bladder distension, inflammation, or rupture; cystitis; possible fine urethral calculi or sediment, and mild bilateral renal and ureteral dilation consistent with a history of urethral obstruction. Gas in the bladder was thought to be iatrogenic. The urine sample obtained by sonographic-guided cystocentesis was submitted for urinalysis and culture. The patient’s urine contained large amounts of protein and blood, but no other abnormalities were noted. The patient was diagnosed with severe chronic cystitis and urethritis resulting in complete lower urinary tract obstruction
As the owners declined urinary catheterization or other more invasive therapies, in hospital medical management was initiated, and included periodic cystocentesis of the bladder, buprenorphine (0.5 mg/kg subcutaneous, 4 times a day, Buprenex, 0.3 mg/ml Solution; Reckitt Benckiser, Richmond, VA USA), meloxicam (1 mg/kg subcutaneous, once a day, Metacam, 5 mg/ml Injectable Solution; Boehringer Ingelheim, St. Joseph, MO USA), enrofloxacin (20 mg/kg subcutaneous, once a day, Baytril, 22.7 mg/ml solution; Bayer Healthcare LLC, Shawnee Mission, KS USA), and subcutaneous fluids as needed to correct dehydration. The patient did not respond over the first 24 hours of hospitalization and remained completely obstructed. Additional treatment options were offered and included humane euthanasia, urinary catheterization, and/or surgical intervention. The owners elected urinary catheterization. The patient was sedated as above, and anesthesia was maintained with sevoflurane via face mask. Urethral catheterization was unsuccessful despite multiple attempts using a small 3.5 french red rubber catheter (Kendall Urethral Catheter, Covidien LLC, Mansfield, MA USA). The owners then agreed to placement of a pigtail catheter transabdominally into the urinary bladder followed by scrotal urethrostomy surgery the following day, with the possible addition of abdominal exploratory surgery to assess the bladder wall integrity, search for possible urinary calculi, and facilitate retrograde passage of a urinary catheter to assist in scrotal urethrostomy. The abdomen was prepared with standard aseptic technique and a sterile pigtail catheter (Pigtail Drainage Catheter Set, Infiniti Medical LLC, Menlo Park, CA USA) was passed transabdominally into the bladder with ultrasound guidance (Figure 3a-b).1-2 Patency was verified and a closed collection system was attached. An intravenous catheter was
placed in the cephalic vein for intravenous fluid administration and postoperative sedation. The patient was monitored overnight in the intensive care unit (ICU) with a constant rate infusion (CRI) of midazolam at (0.1 mg/kg/hr). Fluid intake, urine production, respiratory rate and heart rate were monitored closely while in the ICU. Lactated Ringer’s solution (Veterinary Lactated Ringer’s Injection USP, Abbott Laboratories, North Chicago, IL USA) was infused at 3 ml/hr intravenous. Buprenorphine, meloxicam, and enrofloxacin were continued following the placement of the pigtail catheter. Overnight, urinary output decreased and it was suspected that the pigtail catheter was no longer in the urinary bladder and/or that it was associated with bladder rupture. The squirrel was taken to surgery for abdominal exploratory and scrotal urethrostomy. The patient was adequately sedated from the midazolam CRI and pain appeared well controlled with buprenorphine and meloxicam. The patient was induced and anesthesia maintained with sevoflurane via face mask. The patient was placed in dorsal recumbency. The abdomen, caudal thigh area, and perineal region were clipped using #40 clipper blades with a proximal margin at the base of the sternum, a distal margin at the level of the base of the tail, and wide lateral margins. A surgical prep was performed using povidone-iodine scrub. The patient was transported to the surgical suite and placed in dorsal recumbency. Tape was used to secure the pelvic limbs in place. A clear sterile drape was placed over the patient. A 3 cm ventral midline incision was made from the umbilicus to just cranial to the prepuce through the skin and subcutaneous tissues as well as the abdominal wall through the linea alba using a #15 scalpel blade (Figure 4a). Upon entering the
abdomen, approximately 10 ml of hemorrhagic fluid was present (suspected hemorrhagic urine). The bladder was examined and a small circular approximately 0.5 cm diameter rupture site was present in the ventral wall parallel to the trigone, suspected to be associated with previous pigtail urinary catheterization. The pigtail urinary catheter had exteriorized from the urinary bladder and thus was removed from the abdomen. Stay sutures were placed in the urinary bladder to facilitate manipulation. A 2 cm elliptical incision was then made surrounding the scrotum using a #15 scalpel blade and scrotal tissue and fat were removed. The incision was extended caudally to expose urethral tissue (Figure 4b). The subcutaneous tissue was undermined using Metzenbaum scissors. Hemostasis was maintained using hemostats and digital pressure with sterile gauze. Along the ventral midline of the distal penile urethra, a small stab incision was made using a #15 blade and extended proximally for 2 cm using tenotomy scissors to expose urethral mucosa. A lubricated 3.5 Fr red rubber catheter was placed through the rupture site in the bladder and fed into the urethra to the created stoma (Figure 4c). Patency of the urethra was confirmed. Using 4-0 poliglecaprone 25 (Monocryl Suture, Ethicon, Guaynabo, Puerto Rico), simple interrupted sutures were placed on both lateral sides of the urethral incision, apposing the urethral mucosa and the skin to create the urethrostomy site (Figure 4d). The red rubber catheter was removed and the bladder was flushed with sterile saline to ensure the patency of the urethrostomy site, which was confirmed. A 2 cm incision into the bladder was made extending from the rupture site and the bladder was explored; no uroliths were found. The bladder wall was significantly thickened and had minimal to no contractility on manipulation. The bladder wall was closed with a simple continuous
pattern using 4-0 poliglecaprone 25. Sterile saline was injected into the bladder to ensure adequate closure. No leakage was observed and lower urinary tract was verified as patent. The abdomen was copiously flushed with warm sterile saline prior to closure. The abdominal wall was closed with 3-0 polydioxanone (PDS*II Polydioxanone Suture, Ethicon, Guaynabo, Puerto Rico) in a simple continuous pattern. The skin was closed with 4-0 poliglecaprone 25 in a subcuticular pattern (Figure 4d). A modified Elizabethan collar (E-collar) was placed to prevent self-mutilation of the surgical sites. The patient was monitored post operatively in ICU and medications were continued as previously described. Twenty-four hours postoperatively, the patient had not produced measurable urine, and subcutaneous edema was noted in the cranial half of the body. When the squirrel’s abdomen was palpated at this time there was no evidence of an enlarged bladder. Lung sounds were diffusely harsh with associated crackles, suggestive of pulmonary edema. Serum chemistry panel results were within normal limits. A single dose of furosemide (1.5 mg/kg subcutaneous, Salix; Intervet International GMBH, Germany) was administered once to assess response of the kidneys and to address suspected pulmonary edema. Intravenous fluids were discontinued. Within two hours of receiving furosemide, the squirrel began to produce urine. Intravenous fluids were replaced with fluids administered subcutaneously, as needed, to maintain hydration and assist in flushing of the urinary bladder. Prazosin (0.07 mg/kg orally, 3 times a day, Prazosin HCl, 1 mg capsules; Mylan Pharmaceutical Inc., Morgantown, WV USA) was also prescribed to help prevent urethral spasm.
Overnight, the patient produced moderate amounts of urine (multiple 4-6 cm diameter urine spots on the patient’s towels). On the second day, the patient began eating regularly, was more energetic, while the subcutaneous edema and abnormal lung sounds resolved. The owners elected to continue care at home, and the patient was discharged with oral enrofloxacin (Baytril, 50 mg/ml oral suspension, compounded by Texas A&M University Small Animal Hospital Pharmacy, College Station, TX USA) (20 mg/kg orally, once a day for 14 days), meloxicam (1 mg/kg orally, once a day for 7 days, Metacam, 1.5 mg/ml oral suspension; Boehringer Ingelheim, St. Joseph, MO USA), buprenorphine (0.03 mg/kg orally, 2 – 3 times a day, as needed for discomfort for 5 days, Buprenex, 0.3 mg/ml solution; Reckitt Benckiser, Richmond, VA USA), and prazosin (0.07 mg/kg orally, 3 times a day for 7 days). The owners were instructed to monitor the squirrel’s urine volume and character carefully, and for straining to urinate. Cage rest in a single-level enclosure was prescribed for two weeks following discharge. The owners were instructed to leave the E-collar in place for 10-14 days until the surgical sites had healed, to prevent self-mutilation. The patient returned two days after discharge for reexamination. The patient was doing well according to the owner which included eating, drinking, defecating, and urinating as when the animal was healthy. On physical examination, the patient was apparently euhydrated, with the abdomen being soft on palpation and bladder small. The urethrostomy site was clean and dry with some mild erythema. The ventral midline incision was intact, clean and dry. Due to owner concerns that the patient was not drinking enough water, 45 mL of Lactated Ringer’s solution were administered subcutaneous, and the owners were provided Lactated Ringer’s solution for at-home
use as needed. Medications and monitoring instructions were continued as described above. At an 11 days following the surgical procedure, the squirrel was doing well, but occasionally produced pink-tinged urine associated with mild straining at the end of the urine stream. The E-collar was not used consistently, and the patient appeared to have removed some of urethrostomy sutures, which was otherwise patent and healing well. The owners were instructed to continue use of the E-collar, and to return for a more substantial diagnostic evaluation, including urinalysis if hematuria continued. At 21 days post-surgery, the patient was doing well at home. The owners had been gently cleaning a small amount of debris from the surgical site, but no abnormalities were noted when examined. The urethrostomy site had significantly contracted by approximately 30-50% (Figure 5). Cage rest was discontinued and the owners were instructed to continue monitoring for any signs of lower urinary tract disease. One year following the procedure, the patient had no recurrence of clinical signs associated with lower urinary tract disease.
DISCUSSION Lower urinary tract disease and obstruction occurs sporadically in rodent species; causes include chronic cystitis due to severe urinary tract infection, urolithiasis, accessory sex gland secretion blockage, bacterial infection and abscessation of the accessory sex glands, urogenital neoplasia, and trauma.3-5 As no specific infectious etiology was identified in this case, obstruction was likely due to idiopathic chronic cystitis and urethritis. Idiopathic cystitis resulting in lower urinary tract obstruction is well
documented in feline patients.6-8 Clinical signs of lower urinary tract disease that often precede complete obstruction include hematuria, stranguria, decreased appetite, and lethargy. These clinical signs may culminate in the complete inability to urinate, which can quickly induce severe depression, electrolyte disturbances, azotemia, and death. An ideal diagnostic database for a rodent with suspect urinary tract infection includes urinalysis and urine culture with bacterial antimicrobial sensitivities prior to treatment, diagnostic imaging to rule out radiopaque urolithiasis, abdominal ultrasound to evaluate the urogenital tract, complete blood cell count, and serum biochemistry profile. Treatment for bacterial urinary tract infection in rodents should consist of appropriate antibiotic therapy. Urinary tract obstruction requires placement of a urinary catheter to relieve obstruction, if possible, and treatment of dehydration, azotemia, and electrolyte imbalances. Other medical and surgical management strategies may be indicated as well. Urethrostomy is most commonly performed in castrated male cats to alleviate recurrent or complicated cases of lower urinary tract obstruction.6-8 Other species in which urethrostomy has been documented include small ruminants, antelope species, camelids, equids, dogs, ferrets, a serval, and non-human primates.9-22 A single case of urethrostomy in a rodent species has been reported; this procedure was performed as a salvage procedure in a male rat with preputial adenocarcinoma and subsequent penile amputation.23 Complications of urethrostomy include anesthetic risk, stricture of the surgical site, recurrent ascending bacterial urinary tract infections, urinary incontinence, extravasation of urine, skin necrosis, and self-mutilation of the surgical site. 8-10 Chronic
lower urinary tract obstruction may also lead to bladder dyssynergia due to overdistension of the bladder and/or acute renal failure; development of these conditions may affect the prognosis for the affected individual. The most significant complications noted in this case were pulmonary and subcutaneous edema, and minor disruption of the suture site post surgery, both of which were managed effectively with careful post-operative management and intervention. Of additional concern was contraction of the urethrostomy site, which was not clinically significant in this case; however, risk of stricture must be a consideration for surgical planning. This case report demonstrates successful use of scrotal urethrostomy in an Eastern fox squirrel with severe chronic cystitis-induced lower urinary tract obstruction. Scrotal urethrostomy may be used as an effective treatment of complicated lower urinary tract obstruction in this species with careful post-operative management.
ACKNOWLEDGMENTS The authors would like to thank all the staff and students at Texas A&M University Veterinary Teaching Hospital who helped provide excellent patient care throughout this case as well as Dr. Anton G. Hoffman, DVM, PhD, Presidential Professor for Teaching Excellence and Clinical Professor, Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, who graciously created the artwork for Figure 3b.
REFERENCES 1. Infiniti Medical LLC. “Products: Drainage Catheters (Locking Loop)”. http://infinitimedical.com/products/drainage-catheters/. Last accessed 4 Feb 2015. 2. Kilby MD, Morris RK: Fetal therapy for the treatment of congenital bladder neck obstruction. Nat Rev Urol 11:412-419, 2014 3. Brown C, Donnelly TM: Disease problems of small rodents, in Quesenberry KE, Carpenter JW (eds): Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery (ed 3). St. Louis, MO, Saunders/Elsevier, pp 354-372, 2012 4. Heatley JJ, Harris MC: Hamsters and gerbils, in Mitchell MA, Tully TN (eds): Manual of Exotic Pet Practice. St. Louis, MO, Saunders/Elsevier, pp 406-432, 2009 5. Richardson VCG: Systems and diseases, in Richardson, VCG (ed): Diseases of Small Domestic Rodents. Oxford, UK, Blackwell Publishing, pp 60-67, 141-167, 217238, 2003 6. McLoughlin MA: Complications of lower urinary tract surgery in small animals. Vet Clin North Am Small Anim Pract 41:889-913, 2011 7. 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 53:693-698, 2012 8. Smith CW: Perineal urethrostomy. Vet Clin North Am Small Anim Pract 32:917-925, 2002 9. Bartlett LW: Ferret soft tissue surgery. Semin Avian Exot Pet 11:221-230, 2002 10. Bilbrey SA, Birchard SJ, Smeak DD: Scrotal urethrostomy: a retrospective review of 38 dogs (1973 through 1988). J Am Anim Hosp Assoc 27:560-564, 1991 11. Campbell BG: Prepubic urethrostomy and placement of a caudal superficial epigastric flap for treatment of a self-mutilation injury in a serval. J Am Vet Med Assoc 222:628-632, 2003 12. Duesterdieck-Zellmer KF, Van Metre DC, Cardenas A, et al: Acquired urethral obstruction in New World camelids: 34 cases (1995-2008). Aust Vet J 92:313-319, 2014 13. Fresno L, Fernandez-Moran J, Fernandez-Bellon H, et al: Complicated urethral rupture and scrotal urethrostomy in a Bongo antelope (Tragelaphus eurycerus isaaci). J Zoo Wildlife Vet 39:464-467, 2008
14. Howarth S, Lucke VM, Pearson H: Squamous cell carcinoma of the equine external genitalia: a review and assessment of penile amputation and urethrostomy as a surgical treatment. Equine Vet J 23:53-58, 1991 15. Mutlow AG, Mauch WD, Carpenter JW, et al: Surgical procedure and postoperative management of a perineal urethrostomy in a chimpanzee (Pan troglodytes). J Zoo Wildlife Med 37:381-386, 2006 16. Ramadan RO, Kock RA, Higgins AJ: Observations on diagnosis and treatment of surgical conditions in the camel. Brit Vet J 142:75-89, 1986 17. Ranen E, Freidman T, Aizenberg I: Perineal urethrostomy in a brown capuchin monkey (Cebus apella). J Zoo Wildlife Vet 37:40-43, 2006 18. Larsen SR, Cebra CK, Wild MA: Diagnosis and treatment of obstructive urolithiasis in a captive rocky mountain wapiti (Cervus elaphus nelsoni). J Zoo Wildlife Med 31:236239, 2000 19. Smeak DD: Urethrotomy and urethrostomy in the dog. Clin Tech Small An P 15:2534, 2000 20. Stone WC, Bjorling DE, Trostle SS, et al: Prepubic urethrostomy for relief of urethral obstruction in a sheep and a goat. J Am Vet Med Assoc 210:939-941, 1997 21. Sullivan K, Freeman S, van Huegten E: Impact of two typs of complete pelleted, wild ungulate feeds and two pelleted feed to hay ratios on the development of urolithogenic compounds in meat goats as a model for giraffes. J Anim Physiol An N 97:566-576, 2013 22. Van Weeren PR, Klein WR, Voorhout G: Urolithiasis in small ruminants: a retrospective evaluation of urethrostomy. Vet Quart 9:76-79, 1987 23. Mentre V: Penile Amputation and urethrostomy in a rat. Exotic DVM 9:17-19, 2007
FIGURE LEGENDS Figure 1: Abdominal radiograph, ventrodorsal projection, demonstrating distended bladder, cranial displacement of other abdominal organs, and lack of radiopaque uroliths associated with urethral obstruction. Note subcutaneous fluid pocket on the animal’s left side. Figure 2: Abdominal radiograph, left lateral projection, demonstrating distended bladder, cranial displacement of other abdominal organs, and lack of radiopaque uroliths associated with urethral obstruction. Note subcutaneous fluid pocket on the animal’s dorsum. Figure 3: a) Pigtail drainage catheter set (Pigtail Drainage Catheter Set, Infiniti Medical LLC, Menlo Park, CA USA). b) Schematic representation of ultrasound(C)-guided placement of a pigtail drainage catheter (A) into the urinary bladder (B) of a patient. Figure 4: Intraoperative photographs of techniques utilized during the scrotal urethrostomy procedure in the Eastern fox squirrel. A) Placement of initial abdominal approach relative to the prepuce and scrotum. B) Exposure of the penile urethra after removal of the scrotum and scrotal tissue as well as bladder exteriorization and passage of red rubber catheter to guide urethral incision placement. C) Blue arrow indicating passage of the red rubber catheter tip at level of initial urethral incision. D) Final appearance of scrotal urethrostomy site and abdominal wall closure prior to recovery.
Figure 5: Final appearance of the scrotal urethrostomy site in the Eastern fox squirrel 21 days following the surgical procedure.