Page 229 - Manual of Equine Field Surgery

' Urethral Extension (Urethroplasty) 225

A 30-Fr Foley catheter is placed in the urinary No. 2-0 absorbable suture using a simple contin-

bladder and the cuff is inflated. Before any inci- uous pattern (Figure 41-9).

sion is made, two lines of the ventral vaginal

mucosa are dorsally everted and sutured over the McKinnon Technique

Foley catheter with No. 0 absorbable suture using

a11 interrupted horizontal mattress pattern, Correction of urovagina in mares caused by severe

leaving adequate mucosa to allow excision and perineal conformation abnormalities can be

further suturing (Figure 41-7). Suture placement accomplished with this technique= by providing

is continued caudally to approximately 2 cm a wide, long, and strong urethral extension. This

cranial to the vulvar labiae. The two lines of dor- technique is recommended when the urethra

sally everted mucosa are excised to create four opening needs to be extended far caudally and

fresh-cut edges of vaginal mucosa (Figure 41-8). increased tissue tension is present. Minimal tissue

These debrided edges are then apposed with tension is exerted on the completed tunnel. I11i-

tially, a steep learning curve for this technique is

encountered, but it can be easily performed with

experience. In addition, disruption of the blood

supply should be avoided during the tissue flap

dissection.

A 30-Fr Foley catheter is placed in the urinary

bladder and the cuff is inflated, The caudal border

' of the transverse urethral fold is grasped on

midline with Allis tissue forceps and retracted

caudally. A horizontal mucosal incision is made 2

to 4 cm cranial to the caudal edge of the trans-

verse urethral fold extending slightly dorsocau-

dally along the left and right vaginal walls (Figure

41-10). This incision should end at the vulvar

labia half to two thirds of the distance between the

vaginal floor and vaginal roof. The transverse ure-

thral fold and vaginal wall mucosal tissues are

undermined so that the free tissue flaps are

Figure 41-7 Dorsal eversion of ventral vaginal reflected caudally and axially, respectively. Dis-

mucosa over 30-Fr Foley catheter and sutured using an section of transverse urethral fold tissue should

interrupted horizontal mattress pattern.

Figure 41-8 Excision of dorsally everted vaginal

mucosa, creating four fresh-cut edges of vaginal Figure 41-9 Apposition of freshly debrided mucosa!

mucosa. edges using a simple continuous pattern.