Bovine Reproduction. Группа авторов
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A left flank tube cystotomy provides an economic alternative to tube cystotomy placement and avoids the risks associated with general anesthesia and dorsal recumbency. However, optimal access to the bladder is obtained through a ventral celiotomy. The left paralumbar fossa is aseptically prepped and flank anesthesia is performed. A 10‐ to 15‐cm vertical skin incision is made with a routine celiotomy. Care should be taken to make the paralumbar fossa incision somewhat caudal to allow adequate access to the bladder. A needle and extension set can be used to drain excess urine from the bladder in particularly painful individuals attempting recumbency during surgery. The Foley catheter is placed through a stab incision through the skin and abdominal wall as described above on the caudoventral aspect of the incision. The balloon end of the Foley catheter is then placed through the apex of the bladder wall using a hemostat and bluntly forcing through the bladder wall. The balloon is inflated. If access is possible, a cystotomy should be performed on the dorsal aspect of the bladder to remove as many cystoliths as possible. Often a cystotomy is difficult with a standing procedure, so tube cystotomy alone can be performed, but recovery time will often be prolonged without removal of cystoliths. Closure of cystotomy or cystorrhaphy should be performed with 0 or 2–0 monofilament absorbable suture in an inverting pattern. The balloon of the Foley catheter is then pulled flush against the bladder and abdominal wall. A Chinese finger cuff ligature is used to secure the Foley catheter to the ventral flank. The abdomen and skin are closed in a routine fashion.
A one‐way valve should be affixed to the Foley catheter to prevent air aspiration and minimize bacterial contamination. The fingertip of an examination glove with the tip slit affixed to the Foley catheter is a cheap, convenient one‐way valve. After placement, a tube cystotomy must remain in place for a minimum of 7–10 days before removal to prevent any urine leakage from the defect created by the catheter. Urinary acidification should be implemented postoperatively for uroliths amenable to dissolution. Cystic acidification can also be administered with an acidifying solution seven days postoperatively with commercially available buffered acetic acid solution (Walpole's) or hemiacidrin (Renacidin®) [28]. A less expensive alternative for cystic irrigation is diluted acetic acid or 5% ammonium chloride solution [29]. Once urine dribbling from the preputial orifice or urination is observed, the Foley catheter can be occluded to more safely assess urethral patency prior to removal. One study reported dribbling of urine six to seven days postoperatively and free urine flow from the urethra nine days postoperatively [26]. The Foley catheter should be occluded for 48–72 hours with observed normal voiding before the Foley balloon is deflated and catheter removed. An average of 10–12 days postoperatively is required for small ruminants before successful voiding and Foley catheter removal [12, 23]. However, normal voiding can take as long as four to six weeks, especially if removal of cystoliths is not performed.
Complications of tube cystostomy include occlusion of the tube with blood clots, debris, uroliths, tube kinking, dislodgement or loss of catheter [26], balloon deflation, cystitis, uroperitoneum after catheter removal, adhesions to the urinary bladder, bladder atony, and failure to resolve urethral obstruction. Minimally invasive tube cystotomy [30] and laparoscopic‐assisted placement [31] of cystic catheters have been described in small ruminants. Prognosis for survival in cattle treated with tube cystotomy is reported to be as high as 90% [18]. In cases without urethral rupture, utilization of a tube cystotomy provides a good treatment option for bulls to maintain breeding function.
Cystotomy
A cystotomy is ideally performed under general anesthesia with the individual in dorsal recumbency. Prior to creating the incision, the penis should be exteriorized and secured by clamping the apical ligament of the penis. A paramedian skin incision is performed lateral to the prepuce. The incision should be positioned relatively caudally to ensure adequate access and exteriorization of the bladder [27]. A paramedian or midline celiotomy can be performed. Once the urinary bladder is localized, stay sutures with 2–0 or 0 monofilament can be placed in the bladder to assist with the cystotomy. A routine cystotomy is performed with aspiration of urine. Removal of uroliths from the bladder trigone and proximal urethra can be assisted with the use of a surgical spoon, as well as copious lavage and aspiration of sterile saline. An 8‐ to 10‐French polypropylene catheter is then passed in both a normograde and retrograde direction. Hydropulsion is performed with saline and may relieve the urethral obstruction. However, excessive force and effort are contraindicated due to the risk of damaging the urothelium or causing a urethral rupture. The urethra is considered free of calculi when saline can easily be flushed normograde and retrograde [27]. If urethral patency is not obtained, a tube cystostomy should be performed. The bladder is closed with 2–0 or 3–0 monofilament suture in a single‐ or double‐layer inverting suture pattern. In cases of bladder rupture, the defect should be repaired and/or any necrotic tissue removed. In cases of bladder rupture, aspiration and lavage of the abdomen should be performed. The celiotomy, subcutaneous tissues, and skin should be closed in a routine fashion. Disadvantages of this procedure include the expense and duration of the procedure, potential for urethral rupture, and extensive postoperative urethral swelling resulting in significant stranguria or postoperative obstruction.
Ischial Urethrostomy
Ischial urethrostomy is a viable treatment option for feedlot steers (≥318 kg) and breeding bulls [4, 32]. This procedure is performed under standing epidural anesthesia. The perineal region from the anus to the base of the scrotum is aseptically prepared. A 10‐cm midline skin incision is performed starting over the ischial arch approximately 5 cm ventral to the anus [4]. The dense layer of fascia between the skin and retractor penis muscle is incised to expose the retractor penis muscle [4]. Blunt dissection between the retractor penis muscles reveals the bulbospongiosus muscle [4]. The urethrotomy incision is made through the bulbospongiosus muscle or just distal to its attachment [33]. Excessive hemorrhage is common during this procedure if the urethra incision is off midline and the corpus spongiosum is nicked. A 20‐ to 28‐French Foley catheter is advanced into the bladder. Entrance into the bladder can be assisted with the use of a rigid stylet or curved hemostats to direct the tip over the ischial arch [4]. The Foley balloon is distended with saline and retracted until it is seated into the trigone of the bladder and sutured in place where it exits the skin. A one‐way valve utilizing the fingertip of a glove with a slit should be taped onto the external end of the Foley catheter to prevent air aspiration into the bladder and minimize bacterial contamination. Ideally, impervious plastic should be adhered to the skin just ventral to the anus to prevent fecal contamination of the surgical site. For breeding bulls in which urethral patency is desired, a sterile bandage over the incision with stay sutures and surgical towels is recommended (Figure 20.7).
Figure 20.7 Placement of a plastic or rubber (source‐ automobile inner tube) strip sutured to the perineum dorsal to the surgery site is recommended.
Source: Image courtesy Dwight Wolfe and Misty Edmondson.
For feedlot steers, the catheter can remain in place until desired slaughter weight is reached or the uremia is resolved (~30 days) [32]. Additionally, this procedure can be used when a previous lower perineal urethrostomy site has strictured or reobstructed. In general, the prognosis is greatly reduced for individuals with bladder rupture. However, this technique allows the bladder to remain empty and heal by second intention.
This technique can be a good option of urinary diversion for breeding bulls (without urethral rupture) because the urethral diameter is larger in this region, thus decreasing the risk of urethral stricture. If urethral patency is immediately obtained after the procedure, the Foley catheter can be removed and 3 mm polyethylene