Wedge meatoplasty as a treatment for stricture of the urethral meatus in a cat

Abstract

A three-and-a-half-year-old male neutered Siamese cat presented with idiopathic feline lower urinary tract inflammation and dysuria, which appeared to be caused by stricture of the urethral meatus. Wedge meatoplasty was performed, which relieved the cat’s dysuria and restored a normal urine stream. To my knowledge, this is the first report of meatoplasty as a treatment for stricture of the urethral meatus in a cat.

Case Report

A three-and-a-half-year-old male neutered Siamese cat presented with a 2-month history of intermittent dysuria, pollakiuria and excessive licking of the prepuce/penis. Treatment with unspecified antibacterials, N-acetyl D-glucosamine, Royal Canin Urinary S/O diet and an unspecified homeopathic remedy had produced no improvement. Clinical examination revealed a full, non-painful bladder and pale mucosa at the tip of the penis.

Routine haematology and biochemistry screens were unremarkable. Expression of the bladder under general anaesthesia was possible, but the urine stream was thin. Examination of the penis confirmed that the tissue surrounding the urethral meatus was hard, fibrous and pale, and that the meatus was abnormally small (Figure 1). Analysis of a cystocentesis urine sample revealed slight haematuria, proteinuria, pyuria and hypersthenuria (specific gravity 1.050). Urine bacterial culture of this sample was negative. The urethral meatus was difficult to catheterise with a 4 French Jackson’s cat catheter (Smiths Medical International) but the catheter passed easily along the rest of the urethra. A positive contrast retrograde urethrogram was unremarkable: a double contrast cystogram revealed mild thickening of the bladder wall. Abdominal ultrasonography confirmed the bladder wall thickening, but was otherwise unremarkable. A diagnosis of idiopathic feline lower urinary tract inflammation (FLUTI) was made on the basis of the history, clinical signs and diagnostic test results. Urethral muscle spasm or a stricture of the urethral meatus was suspected as the cause of the cat’s dysuria.

Figure 1

Photograph of the cat’s penis at presentation showing small urethral meatus with surrounding pale discoloration of the penile mucosa

Medical treatment was given with intramuscular buprenorphine 20 μg/kg q8h (Vetergesic; Alstoe Animal Health), phenoxybenzamine 0.5 mg/kg PO q12h (Dibenyline; Goldshield Pharmaceuticals), diazepam 2 mg PO q8h (Valium; Roche) and intravenous Hartmann’s solution 3 ml/kg/h (Aquapharm 11; Animalcare). Twenty-four hours later there was no improvement in the cat’s dysuria so an indwelling urinary catheter (Slippery Sam; Smiths Medical International) was placed and connected to a closed urine collection system (Infusion Concepts).

The catheter was removed 24 h later; the cat remained dysuric. Urinalysis of a cystocentesis sample was unremarkable apart from slight haematuria. Examination of the distal penis under general anaesthesia confirmed the previous findings and a stricture of the urethral meatus was strongly suspected. A wedge meatoplasty was performed to widen the urethral orifice: an approximately 3 mm long triangular section of the dorsal wall of the distal urethra and overlying penile mucosa was removed, with the apex directed proximally and the base at the meatus (Figure 2). The urethral mucosa was sutured to the penile mucosa using simple interrupted sutures of 0.7 metric polyglactin 910 (Vicryl; Ethicon).

Figure 2

Intraoperative photograph of the cat’s penis after resection of v-shaped wedge of tissue from the dorsal aspect

Postoperatively medical treatment with buprenorphine, phenoxybenzamine and Hartmann’s solution was given as detailed above. An Elizabethan collar was used to prevent self-trauma. The cat showed no evidence of dysuria, produced a good urine stream and was discharged 48 h postoperatively with medical treatment with meloxicam 0.05 mg/kg PO q24h for 5 days (Metacam; Boehringer Ingelheim) and a further 7-day course of phenoxybenzamine. The owner was given management advice with regard to litter tray number and placement, minimising stress, feeding a commercial canned diet, encouraging water intake, and encouraging exercise and outdoor activity.

At re-examination 7 days postoperatively, the owner reported that the cat was urinating normally. Clinical examination revealed that the penis appeared to be healing uneventfully. Medical treatment was discontinued and the owner was asked to continue management of the cat at home as described above. At re-examination 21 days postoperatively the penis had completely healed and the inflammation had resolved. The cat remained free of clinical signs 12 months later.

Penile urethral strictures in cats have been reported associated with damage from repeated or traumatic urethral catheterisation. ¹ There was no history of previous urethral catheterisation in this case, however. The location of the stricture and history of excessive grooming of the area suggest that self-trauma may have caused the stricture here. The stricture was most likely not visible on a positive-contrast urethrogram because its location was distal to the tip of the catheter used to introduce the contrast material. The negative urine culture in the face of pyuria is consistent with previous reports that while pyuria is a common finding in cats with FLUTI associated with feline idiopathic cystitis (especially males that are obstructed), ² only 1–22% of cats with FLUTI have a positive urine culture.^3–7

Medical treatment was given initially despite the suspicion of meatal stricture to rule out urethral muscle spasm as a possible cause of the dysuria. An indwelling catheter was used for 24 h to relieve the cat’s dysuria while giving medical treatment more time to work. After 48 h the complete lack of response to treatment and the consistent abnormal appearance of the meatus suggested stricture as a more likely cause and thus surgical treatment was pursued. Perineal urethrostomy was considered for this case. ⁸ However, meatoplasty was chosen as a first-line treatment owing to the distal location of the stricture, potential complications of perineal urethrostomy^9,10 and the possibility of performing perineal urethrostomy at a later date if meatoplasty was unsuccessful.

In humans, stricture of the urethral meatus and/or fossa navicularis (the terminal portion of the penile urethra) has been reported as a result of recurrent balanoposthitis, ¹¹ balanitis xerotica obliterans, ¹² junctional epidermolysis bullosa, ¹³ exposure to sulphur mustard ¹⁴ and as a complication of hypospadias repair.^15,16 Non-surgical therapy of meatal strictures in humans has been reported using repeated sounding of the meatus,^17–19 and combined dilation of the meatus and application of topical corticosteroid. ²⁰ Sounding was considered inappropriate in this case as repeated sedation or general anaesthesia would be required and because of concern that the apparent fibrosis around the meatus would limit its effectiveness. Various meatoplasty techniques have been used for treatment of meatal stricture in humans including ventral transverse island fasiculocutaneous penile flap ²¹ , dorsal and ventral meatotomy with a v-shaped relieving incision, ²² eversion meatoplasty, ²³ resection and primary end-to-end anastomosis, ²⁴ meatoplasty with double buccal mucosa grafts, ²⁵ or a dorsal preputial island flap ²⁶ and meatoplasty with various other local skin flaps or free skin grafting. ¹¹

Here, a simple wedge meatoplasty similar to the eversion meatoplasty described by el-Kasaby et al ²³ and the Mathieu and a V incision sutured (MAVIS) modification of the Mathieu technique for hypospadias repair ²⁷ was used: more complicated techniques involving flaps or grafts were considered inappropriate because of the small diameter of the cat’s urethra. Multifilament absorbable suture material was chosen here for mucosal apposition on the basis of the described technique of eversion meatoplasty, ²³ availability of the required size, because its softer nature might cause less postoperative irritation than a monofilament material and because it would not require removal and the consequent possibility of trauma to the delicate mucosal apposition. Use of a multifilament absorbable material did not appear to adversely affect healing.

Postoperative complications after meatoplasty in humans include abnormal urine stream,^23–26 glanular torsion, ²⁴ abnormal appearance of the meatus, ²⁷ wound dehiscence,^11,28 fistula formation^27,28 and stricture formation ²⁴ . Complications were not seen in this case. Stricture formation and dehiscence were considered possible complications in this case as accurate mucosal apposition was technically challenging. Use of an operating microscope or loupes might allow use of a finer suture and more accurate suture placement, minimising this risk.

Assessment of the effect of meatoplasty in humans is often subjective, based on history and clinical examination findings, including examination of the urine stream; ²⁹ the same criteria were used to assess this case. Uroflowmetry has been proposed as a more objective measure of treatment effect, ²⁹ but, to my knowledge, it is not yet available to veterinary patients.

To my knowledge this is the first report of stricture of the urethral meatus and wedge meatoplasty in a cat. Wedge meatoplasty appeared to be an effective treatment in this case: further investigation is warranted to determine its efficacy and safety in a larger number of cases.