Equine field surgery- Urogenital surgery (Proceedings)

Urogenital Surgeries - Female

     • Perineal body reconstruction (Episioplasty)

     • Urethroplasty

     • 3o Rectovaginal tear repair

     • Rectovaginal fistula repair

Perineal Body Reconstruction (Episioplasty)

     Indication

     • Pneumovagina or persistent endometritis following Caslick's procedure

     Equipment

     • No special equipment is required.

     Preparation

     • Sterile saline is used instead of alcohol to remove antiseptic soaps, because alcohol may cause excessive perineum irritation

     Procedure

     • Vulvar retraction

     • Triangular areas of mucosa are removed from the perineal body

     • The resultant exposed submucosa forms a right-angled triangle

     • Closure of the ventral vestibular mucosal margins is performed cranial to caudal

     • Caslick's procedure is performed to appose the vulvar opening

     Expected Outcome

     • Adequate reconstruction alleviates pneumovagina in most cases

     • Occasionally, pneumovagina does not resolve following Caslick's procedure or perineal body reconstruction

     • In these cases, perineal body transection may be warranted

     Complications

     • Minimal

     • Dehiscence

     • Suture sinus tract development

     • Excessive ventral closure may result in urovagina

Urethroplasty

     Indications

     • Urine pooling, urovagina

     Equipment

     • Long-handled instruments

     • 30-Fr Foley catheter

     • Self-retaining retractors (vaginal spatula, Balfour, modified Finochietto)

     • Good light source (floor lamps, headlamp, or fiberoptic lights)

     Procedure

     • Various techniques described

     • Goal of all techniques is to create a mucosal tunnel extending from the urethral orifice to near the mucocutaneous junction

     • Important to place the first suture cranial to the urethral orifice to minimize the risk of fistula formation and to appose the dissected tissue shelves with minimal tension

     Techniques

     • Monin

     • Brown

     • Shires

     • McKinnon

     Urethroplasty - Monin Technique

     • Involves caudal translocation of the transverse urethral fold

     • Recommended only in cases with mild perineal conformational abnormalities

     • Major limitation

          – inability to extend the urethral opening as far caudally as other techniques

     Urethroplasty - Brown Technique

     • Most common urethral extension technique used

     • Severe perineal conformation abnormalities

     • Extends urethral opening far caudally

     • Vaginal scars or vaginal mucosa atrophy are not good candidates for this technique because of increased tissue tension

     Urethroplasty - Shires Technique

     • Simple, efficient, and with minimal hemorrhage

     • Mares must have redundant vestibular folds

     • No dissection or undermining tissue flaps to form a shelf

     Urethroplasty - McKinnon Technique

     • Severe perineal conformation abnormalities

     • Provides a wide, long, and strong urethral extension

     • Recommended when the urethra opening needs to be extended far caudally and increased tissue tension is present

     • Minimal tissue tension is exerted on the completed tunnel

     Expected Outcome

     • Primary healing ~85% to 89%

     • Short-term complications ~11-15%

          – Dehiscence

          – fistula formation

          – subsequent surgeries are essential to improve the chances for complete healing

     • Postoperative conception rates ~64-92%

     • Recurrence uncommon

     Complications

     • Suture dehiscence

     • Fistula formation

     • Precise dissection, meticulous suture placement, and reduced tension on apposed tissues will help to minimize

     • If a fistula develops, repair to minimize the risk of endometritis, persistent urovagina, and infertility

     • indwelling urinary catheter may result in cystitis

3o Rectovaginal Tear Repair

     Indications

     • Dystocia

     • Traumatic breeding

     • Conversion of a rectovaginal fistula into a third-degree perineal laceration for subsequent repair

     Equipment

     • Long handled instruments

     • Monofilament absorbable suture materials

     • Self-retaining retractors (Balfour, modified Finochietto)

     • Good light source (floor lamps, headlamp, or fiberoptic lights) are useful but not required

     Preparation

     • Surgery delayed for 4 to 6 weeks

     • Delaying allows the wound edges to strengthen and become clearly defined

     • Gruel or grass-hay diet is fed 3 to 5 days prior to surgery

     • Fasted 1 day before surgery

     Procedure

     • One- and two-stage techniques

     • One-stage repair is preferred

     • Two-stage repair if excessive tension is present

     • Principles for all techniques

          – creation of rectal and vaginal shelves

          – minimal tissue tension

          – maintain soft manure consistency after surgery

     3o Rectovaginal tear repair Techniques

     • One-Stage Techniques

          – Goetz

          – Modified Goetz

          – Semitransverse

     • Two-Stage Technique

          – Aanes

     3o Rectovaginal tear repair - Goetz Technique

     • six-"bite" pattern

     • pattern begins within the vaginal lumen

     • Sutures are positioned approximately 1 cm apart

          – includes the vaginal mucosa

          – does not penetrate the rectal mucosa

          – vaginal mucosa is closed over the newly created rectovaginal shelf

          – rectal mucosa is left to heal by second intention

     3o Rectovaginal tear repair - Modified Goetz Technique

     • Vaginal mucosa is inverted into the vaginal lumen

     • Purse-string sutures are used to close the rectovaginal shelf

          – Sutures are positioned approximately 1 cm apart and should not pass through the vaginal or rectal mucosa

          – rectal mucosa is inverted into the rectal lumen

          – Closure of the rectovaginal shelf and mucosal surfaces should extend to the cutaneous perineum

     3o Rectovaginal tear repair - Semitransverse Closure Technique

     • Combination of building rectovaginal shelf and Episioplasty

     • Rectal and vaginal mucosae are undermined approximately 7 to 10 cm from the rectovaginal shelf

     • The center of the rectovaginal shelf is grasped with Allis tissue forceps, pulling the shelf caudally to the cranial border of the proposed perineal body. The final configuration is in the shape of a "Y" with the base of the Y pointing caudal

     3o Rectovaginal tear repair - Two-Stage Repair - Aanes Technique

     • The vaginal mucosa is inverted into the vaginal lumen

     • Purse-string sutures are used to close the rectovaginal shelf

     • Rectal mucosa may be inverted into the rectal lumen

     • Closure of the rectovaginal shelf is continued to the level of the cutaneous perineum.

     Aanes Technique - Stage Two

     • Closure of the perineal body is performed 3 to 4 weeks after the first surgery if the rectovestibular shelf is completely healed

     • If dehiscence or a fistula is present, the first stage must be repeated

     • Local anesthesia of the perineal body or epidural anesthesia is used

     • Episioplasty performed

     Expected outcome

     • Primary healing ~75-90%

     • Short-term complications ~ 12-24%

          – Dehiscence

          – fistula formation

          – Subsequent surgeries are essential when complications arise to improve the chances for complete healing

     • Conception rates ~75-92% within 1 year

     • Third-degree lacerations recur in 5% to 50% of foaling mares

     Comments

     • If epidural anesthesia is insufficient, desensitize the perineal area by infiltrating local anesthetic laterally between the rectum and the pelvis (at 9-10 o'clock and 2-3 o'clock)

Rectovaginal Fistula Repair

     Indications

     • Dystocia

     • Traumatic breeding

     • Unsuccessful third-degree perineal laceration repair resulting in rectovaginal fistula formation.

     Equipment

     • Long-handled instruments

     • Monofilament absorbable suture materials

     • An 80-degree scalpel handle is helpful

     • Self-retaining retractors (Balfour, modified Finochietto)

     • A good light source (floor lamps, headlamp, or fiberoptic lights)

     Preparation

     • Surgery is delayed for 4 to 6 weeks following fistula formation to allow wound contraction and inflammation to subside

     • allows the wound edges to strengthen and become clearly defined before repair is attempted

     • Gruel or grass-hay diet is fed 3 to 5 days

     • Fasted 1 day before surgery

     Procedure

     • Principles for all techniques include

          – complete debridement of the fistula margin

          – minimal tension on the repair

          – maintain a soft manure consistency after surgery

     Rectovaginal fistula repair - Direct Repair

     • Fistulas up to 10 cm

     • Complete fistula margin debridement is the major limitation of the direct repair

     • Dilate the anal sphincter with self-retaining retractors or umbilical tape plus towel clamps or retention sutures

     • The fistula margin is incised circumferentially exposing the submucosal tissue and incised edges of the rectal and vaginal mucosae

     • Appose submucosa transversely

     • Preplace all sutures

     • avoid purchase of the rectal and vaginal mucosa

     • The rectal mucosa is then apposed transversely

     • Closure of the vaginal mucosa is optional

     Rectovaginal fistula repair - Schönfelder Technique

     • Fistulas up to 6 cm, avoids excessive tension on wound closure and minimizes swelling and pain after surgery.

     • Full-thickness fistula debridement

     • U-shaped vaginal tissue (mucosa and submucosa) pedicle flap is made from the lateral vaginal wall closest to the fistula

     • Rotate the flap to cover the defect

     • Vaginal mucosa faces dorsally into the rectum and its margins should extend at least 2 mm beyond the fistula margin

     Rectovaginal fistula repair - Bemis Technique

     • For large fistulas

     • Major limitations

          – reduced exposure

          – difficult closure of large cranially located fistulas

          – increased scar tissue formation may compromise the elastic nature of the dorsal vagina

     Rectovaginal fistula repair - Huber Technique

     • a combination of the Bemis and conversion to third-degree laceration techniques

     • can be used to repair large fistulas

     • Longitudinal division of the vaginal shelf provides excellent exposure and surgical access for suture placement

     • Healthy tension-absorbing rectal tissues located between the fistula and perineum are preserved, and broad, generous shelves of perirectal and perivaginal tissues are created

     Rectovaginal fistula repair - Klug Technique

     • Fistulas up to 6 cm

     • Provides good visualization, a durable and stable closure, and good first-time healing success rate without disrupting the anal sphincter integrity

     • Tissue mobilization is difficult in large fistula repairs

     • Cranially located fistulas should not be performed with this technique

     Rectovaginal fistula repair - Conversion to Third-Degree Perineal Laceration

     • Large diameter, cranially located, or if minimal perineal tissue is present

     • Incise from the caudal margin of the fistula through the perineal tissues, anal sphincter, and dorsal vulvar commissure

     • Repair 3rd degree as previously described

     Expected Outcome

     • Primary healing ~65-100%

     • Short-term complications ~ 6-35%

          – Dehiscence

          – fistula formation

     • Subsequent surgeries are essential to resolve complications

     • Postoperative conception rates ~33-92%

     • Recurrence during subsequent foalings ~8-10%

     Complications

     • Suture dehiscence

     • fistula development

     • Fistula recurrence => endometritis, pneumovagina, or continued fecal contamination

     • Urovagina

     • Subsequent birthing trauma due to reduced elasticity

     • Tenesmus and constipation

Thanks to my co-authors

Dr. Joanne Kramer

Dr. Georghe Constantinescu

Dr. Keith Branson

Dr. John Janicek

Dr. Lawrence Galle

Dr. Gal Kelmer

Dr. Rick Howard

References

Adams SB, Fessler JF, editors: Atlas of Equine Surgery, Philadelphia, 2000, WB Saunders Co.

Auer JA, Stick JA, editors: Equine Surgery, 3rd ed. Philadelphia, 2006, WB Saunders Co.

McIlwraith CW, Robertson JT, Turner AS, editors: Equine Surgery: Advanced Techniques, 2nd ed. Ames, IA, 1998, Blackwell Publishing.

McIlwraith CW, Robertson JT, Turner AS, editors: Equine Surgery, 2nd ed. Philadelphia, 1998, Lippincott Williams & Wilkins.

Wilson DA, Kramer J, Constantinescu GM, Branson KR, editors. Manual of Equine Field Surgery, St Louis, 2006, Elsevier.