Chapter 62 - Vulva, vestible, vagina and cervix Flashcards
name the vulvar abnoramlities:
- Pneumovagina
- caslick procedure - Innefective vestibular constrictor muscles
- perineal body reconstruction - Urovagina
- Pouret or perineal body transection
- caudal relocation of transverse fold (Monin)
- Caudal urethral extension with 3 tx:
I - Brown technique
II - Shires technique
III - Mckinnon technique
IV - Combined Brown and Mckinnon technique - Perineal lacerations (First, second, third degree)
4.1 - Two-stage repair
4.2 - Single stage repair - Rectovestibular Fistula
- horizontal approach through perineal body
- direct suturing technique - Cervical injury laceration
-Knowles cervical forceps
-stay sutures - Cervical adhesions
-sharp dissection - Cervical incompetence
- buried retention suture
8.Squamous cell carninoma of clitores
-sinusectomy - congenital anomalies (cervical aplasia, double cervic, congenital incompetent cervix)
- ovariohysterectomy - Vaginal varicosities
- ligation, cauterization, laser photocoagulation
What are the primary structures of the caudal reproductive tract?
Vulva, vestibule, vagina, and cervix.
What conformational abnormalities can predispose a mare to infertility?
Pneumovagina, urine pooling, cervicitis, and metritis.
What two structures define the perineum?
The vulva and the base of the tail.
What structures bound the perineum laterally?
Semimembranosus muscles and sacrosciatic ligaments.
What is the typical length of the external orifice of the vulva?
12 to 15 cm.
What forms the dorsal commissure of the vulva?
The labia meeting dorsally, located ventral to the anus.
What forms the ventral commissure of the vulva?
The labia meeting caudal and ventral to the ischial arch.
What fraction of the vulvar cleft should lie ventral to the ischial arch?
Approximately two-thirds.
What degree of deviation from the horizontal plane is considered normal for vulva conformation?
Less than 10 degrees.
What muscle lies deep to the skin of the vulva?
Constrictor vulvae muscle.
Which vessels provide blood supply to the vulva, labia, and clitoris?
Internal pudendal vessels.
What nerves innervate the muscles of the vestibule and vulva?
Pudendal and caudal rectal nerves.
Where is the perineal body located?
Between the anus and vulva.
What forms the perineal body?
External anal sphincter and constrictor vulvae muscles.
What is the homologue of the penis in the mare?
The clitoris.
Where is the clitoris located?
At the ventral commissure of the vulvar labia.
What is the approximate diameter of the clitoral glans?
About 2.5 cm.
What is the primary composition of the clitoral glans?
Erectile tissue, similar to the corpus cavernosum penis.
What structure surrounds the glans of the clitoris?
Clitoral fossa
How long is the body of the clitoris?
Approximately 5 cm.
What does the body of the clitoris attach to?
The ischial arch by two crura.
What is the vestibule, and where does it connect?
The terminal part of the genital tract, connecting the vulva to the vagina.
What is the typical length of the vestibule?
12 to 15 cm.
What is the cranial extent of the vestibule marked by?
The transverse fold, located dorsal to the external urethral orifice.
What muscle covers the lateral and ventral surface of the vestibule?
Constrictor vestibuli muscle.
Where is the vestibular sphincter formed?
By the constrictor vestibuli muscles, hymen pillars, and pelvic floor.
What part of the reproductive tract does the vagina extend to?
From the transverse fold to the vaginal fornix around the cervix.
What structures are adjacent to the vagina dorsally and ventrally?
The rectum dorsally, the bladder and urethra ventrally.
How is the cranial part of the vagina covered?
Mostly retroperitoneally, with some peritoneal coverage based on rectal and bladder fullness.
What vessels supply blood to the vagina?
Internal pudendal vessels.
Why does the vagina lack motor innervation?
It has no skeletal muscle.
What type of ganglia are found in the vaginal wall?
Sympathetic ganglia.
What structure separates the caudal reproductive tract from the uterus?
The cervix.
Where is the external cervical os located?
In the cranial aspect (fornix) of the vagina.
What is the primary function of the cervix?
Acts as a sphincter, separating the caudal reproductive tract from the uterus.
What is the mucosal lining of the cervix characterized by?
Many longitudinal folds.
Name the three protective barriers in the caudal reproductive tract.
Constrictor vulvae muscles, vestibular sphincter, and cervix.
What consequence might result from the incompetency of these barriers?
Contamination of the reproductive tract, potentially leading to infertility.
What is the economic impact of infertility in mares?
Significant impact on the equine industry
Which muscle blends with the constrictor vulvae muscle caudally?
Constrictor vestibuli muscle.
What can cause failure of the protective barriers in the caudal reproductive tract?
Conformational abnormalities, trauma from breeding, or foaling.
Name three conformational abnormalities that predispose a mare to pneumovagina.
Flat croup, sunken anus, and underdeveloped vulvar labia.
In what type of mares is poor perineal conformation often found?
Older multiparous mares with thin body condition.
List two common types of injuries to the caudal reproductive tract that may occur during foaling.
Cervical lacerations and perineal lacerations.
What injury involves the creation of an abnormal opening between the rectum and the vestibule?
Rectovestibular fistula.
What complication may result from untreated trauma to the reproductive tract?
Infertility.
How does perforation of the vagina typically occur during breeding?
During intromission, especially if the stallion is large or overly vigorous.
What can develop if semen enters the peritoneal cavity during breeding?
Peritonitis.
What is the term for an accidental entry of the stallion’s penis into the mare’s rectum?
Emperforation.
What external examination is essential for assessing potential reproductive tract issues?
Evaluation of perineal and vulvar conformation.
Why is the conformation of the vulva critical in the mare’s reproductive health?
It acts as the first line of defense against contamination.
What index is used to evaluate the risk of ascending infections in the reproductive tract?
Pascoe’s Caslick Index.
What value on the Caslick Index is associated with higher pregnancy rates?
Less than 150.
Name one internal examination technique for the reproductive tract of a mare.
Speculum examination.
Why are endometrial biopsy, culture, and cytology samples important?
To assess for infection or other reproductive health issues.
What type of drug is acetylpromazine, and what does it provide?
A tranquilizer, providing sedation without analgesia.
What two drugs are commonly used for sedative-hypnotic effects in horses?
Xylazine hydrochloride and detomidine hydrochloride.
Why might reduced drug dosages be used for draft breeds?
They achieve desired effects at lower doses than lighter breeds.
How is epidural anesthesia achieved in mares?
By injecting anesthetic between the dura mater and periosteum.
What is the purpose of caudal epidural anesthesia?
To block sensory innervation without affecting motor control.
here is the typical injection site for caudal epidural anesthesia?
Sacrocaudal or first intercoccygeal vertebral space.
What technique is used to confirm epidural needle placement?
Hanging drop technique.
What complication may arise from multiple epidural injections?
Scar tissue formation over the intercoccygeal space.
What combination of drugs provides extended analgesia with mild ataxia?
Lidocaine and xylazine.
What drug class does xylazine belong to and what does it provide in epidural use?
α2-adrenergic receptor agonist, providing profound analgesia.
Figure 62-1. Muscles of the perineal region. a, Retractor clitoridis; b,
external anal sphincter (cranial superficial part); c, levator ani; d, subanal
loop of levator ani; e, ventral part of levator ani; f, urethralis; g, external
anal sphincter (caudal superficial part); h, perineal septum; i, crus clitoridis
(cut); j, constrictor vestibuli; k, constrictor vulvae.
Figure 62-2. Drawing of a sagittal section of the muscles that are part
of the vulvar and vestibular sphincters and the perineal body. a, External
anal sphincter; b, internal anal sphincter; c, internal anal sphincter; d,
external anal sphincter; e, muscular fibers from external anal sphincter
to constrictor vulvae; f, cranial superficial part and deep part of external
anal sphincter; g, rectal musculature; h, rectovaginal septum; i, vaginal
musculature; j, vaginal musculature; k, rectal part of retractor clitoridis;
l, clitoral part of retractor clitoridis; m, subanal loop of levator ani; n,
decussation of retractor clitoridis; o, perineal septum; p, clitoral sinus; q,
glans clitoris; r, clitoral fossa.
Figure 62-3. Modified Finochietto retractor with long blades. This retractor is very useful for certain surgical procedures of the caudal reproductive tract, such as repair of a cervical laceration.
Figure 62-4. Long-handled surgical instruments.
Figure 62-5. Caslick procedure. (A) Removal of narrow strip of tissue from mucocutaneous junction. (B) Closure using Ford interlocking pattern.
What predisposes mares to pneumovagina?
Poor perineal conformation, such as a sunken anus, flat croup, and thin body condition.
What are common injuries in the caudal reproductive tract from foaling?
Cervical lacerations, perineal lacerations, rectovestibular fistulas, and uterine prolapse.
What can happen if vaginal perforation occurs during breeding?
Peritonitis can develop if semen enters the peritoneal cavity.
What factors increase the risk of rectal injury during breeding?
Poor vulvar conformation, a small vulvar opening after Caslick procedure, and relaxed anal sphincter.
Why is it important to examine the conformation of the vulva in mares?
The vulva acts as the first line of defense against contamination of the reproductive tract.
What is the Pascoe’s Caslick Index used for?
To assess the risk of ascending infection based on vulvar length and angle
What does the presence of air rushing into the vagina upon labial separation indicate?
A predisposition to pneumovagina.
What clinical signs indicate urovagina?
Pooling of urine in the vagina, often accompanied by perineal conformation issues.
Why is the sacrocaudal vertebral space chosen for epidural anesthesia?
It blocks sensory innervation without impairing hind limb motor control.
What is the hanging drop technique in epidural anesthesia?
It confirms placement by observing fluid aspiration when in the epidural space.
What complications can arise from local anesthetic epidural injections?
Ataxia and possible recumbency due to motor and sensory blockade.
What instruments are essential for caudal reproductive surgeries?
Long-handled instruments, headlamps, and retractors like the Finochietto retractor.
What complication can arise from the Caslick procedure if the vulvar cleft is overly closed?
Urovagina, where urine pools in the vagina.
What anesthesia approach is recommended for perineal body reconstruction?
Epidural or local infiltration anesthesia with the mare sedated.
What is the main purpose of a Caslick procedure?
To prevent pneumovagina by sealing the vulva and reducing air aspiration.
Why is the dorsal commissure of the vulva included in a Caslick procedure?
To ensure a complete seal at the dorsal aspect.
What is a breeding stitch, and when is it used?
A suture at the ventral limit of a Caslick to protect it during breeding, removed after pregnancy confirmation.
What are signs that excessive closure in Caslick procedures has occurred?
Difficulty passing a tube speculum and potential urovagina development.
Why is an episiotomy performed in mares with a Caslick procedure before foaling?
To prevent vulva and perineum tearing during foaling.
What muscle function is targeted in perineal body reconstruction?
The constrictor vulvae and vestibular sphincter.
Damage to the perineal body occurs from repeated stretching of these muscles in older multiparous mares, or from foaling trauma (second-degree rectovestibular injury).
What is the primary goal of perineal body reconstruction?
To restore vestibular sphincter function and proper vulvar orientation.
what other name has the perineal body reconstruction?
episioplasty or Gadd technique and perineal body reconstruction
Describe the first steps of reconstruction of perineal body reconstruction
- The surgery is performed with the mare sedated and restrained in stocks.
- Epidural anesthesia or local infiltration is used to desensitize the surgery site.
- The labia are retracted to the side using towel clamps or stay sutures.
- An incision is made along the mucocutaneous junction of the labia in a dorsoventral direction and is extended craniad along the dorsal commissure of the vestibule to the level of the vestibulovaginal sphincter.
- Dissection is continued submucosally from the dorsum and dorsolateral aspects of the vestibule. The triangular tissue flaps of mucosa are dissected so that they approximate the shape of the perineal body. Using caudal dorsal retraction on the stay sutures, the desired position for closure of the tissues is chosen (Figure 62-7).
Describe the perineal reconstruction steps suturing
- The vestibular mucosa is closed using USP size 2-0 or 0 absorbable suture material in a horizontal mattress pattern, inverting the mucosa into the vestibule.
- The submucosal tissue is closed beginning at the cranial aspect of the vestibule using USP size 0 or 1 absorbable suture material in an interrupted pattern.
- The labial skin is apposed as for the Caslick procedure.
What is the recommendation after perineal reconstruction?
4 weeks of sexual rest
Diameter of vestibule is decreased with this procedure episiotomy may be required at the time of foaling
What is the recommended lidocaine dose for equine epidural anesthesia?
5-7 mL of 2% solution per 500 kg body weight.
How long does detomidine provide analgesia when used epidurally?
Approximately 2-3 hours.
Why should anesthesia volume be limited in epidurals?
Excessive volume can cause ataxia by cranial migration of the anesthetic.
Figure 62-6. Breeding stitch placed ventral to a Caslick suture. (A) Large suture material or umbilical tape is placed in a simple interrupted pattern. (B) The suture is tied and the ends are cut short so that they do not contact the stallion’s penis during breeding.
Figure 62-7. Perineal body reconstruction. (A) The triangular piece of mucosa to be excised from the dorsal vestibule is outlined. (B) The dorsal portion of the vulva and vestibule are retracted caudad and the vestibular mucosa is closed. (C) Submucosal tissues are apposed with a series of interrupted absorbable sutures. (D) The labial skin is closed with interrupted sutures and the vulva is now oriented in a more vertical position.
What condition does perineal body transection treat in mares?
Pneumovagina and urovagina.
Who developed the perineal body transection technique?
Pouret.
Why is epidural anesthesia preferred for perineal body transection?
It desensitizes the area without causing complete motor blockade.
What length incision is typically made for perineal body transection?
A 4-6 cm horizontal incision.
Where is the initial incision made in perineal body transection?
Midway between the ventral anus and dorsal commissure of the vulva.
How far does the dissection continue craniad in perineal body transection?
8 to 14 cm.
What is the purpose of placing a hand in the vestibule during dissection?
To guide the dissection and avoid entering the rectum or peritoneal cavity.
What anatomical change does perineal body transection achieve?
Repositions the vulva to a more vertical orientation.
What type of closure may be used after perineal body transection?
Transverse or T-shaped skin closure.
What is the alternative to skin closure in perineal body transection?
Allowing the wound to heal by second intention.
How long should natural breeding be delayed post-surgery?
Until healing, approximately 3 weeks.
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Figure 62-8. Perineal body transection. (A) The dotted line shows the plane of dissection between the rectum and the caudal reproductive tract. (B) Dissection is performed craniad using a combination of blunt and sharp separation of tissues until the vulva assumes a more vertical orientation.
Figure 62-9. Monin urethroplasty. (A) Incision of the transverse fold of the urethra. (B) Mucosal incisions in walls of the vestibule. (C) Caudal retraction of the transverse fold in preparation for suturing. (D) Completed Monin urethroplasty. (E) Two-layer closure using horizontal mattress pattern.
Figure 62-10. One complication of the caudal urethral extension procedures is fistula formation. Tips of scissors are sticking through the fistula.
Figure 62-11. Brown technique of caudal urethral extension. (A) The transverse fold is split into dorsal and ventral shelves, and the incisions are continued caudad along the ventrolateral walls of the vestibule. (B) The first suture line inverts the vestibular mucosa into the new urethral lumen. (C) The second suture line apposes the submucosal tissues. (D) The third suture line everts the vestibular mucosa into the vestibule.
Figure 62-12. Shires technique of caudal urethral extension. (A) Vestibular mucosa is apposed over a Foley catheter using horizontal mattress sutures. (B) The everted mucosal ridge is excised. (C) The exposed submucosa is apposed using a continuous suture pattern.
Figure 62-13. McKinnon technique of caudal urethral extension. (A) Horizontal incision is made in the mucosa of the transverse fold. (B) Dissection is continued caudad high along the vestibular wall to create large tissue flaps. (C) Apposition of the tissue flaps is accomplished using a continuous horizontal mattress pattern. (D) Completed urethral extension.
Figure 62-14. Combined Brown and McKinnon technique of caudal urethral extension. (A) The scalpel is used to split the free edge of the transverse fold into dorsal and ventral shelves. (B) and (C) Dorsal and ventral mucosal shelves are created by undermining the vestibular mucosa. The dissection should allow the shelves to meet on the midline without tension. (D) The midpoint of the horizontal shelf is retracted caudad, and the ventral shelf is closed using a continuous horizontal mattress pattern to invert the tissue into the newly created urethral tunnel in a Y pattern. (E) The dorsal shelves are sutured using a continuous horizontal mattress pattern to evert the tissue into the vestibule (a). An additional continuous everting suture is placed around the three portions of the Y and tied at the end to provide further support to this very vulnerable location (b). Close-up view of the new urethral shelf with the two everting patterns (c). (F) The completed urethral extension.
Figure 62-15. Completed urethral extension described in Figure 62-14 with a urinary catheter in place.
Figure 62-17. Appearance of a third-degree perineal laceration that is ready for repair. The rectal mucosa overhangs the intact shelf at the cranial extent of the laceration. Arrows point to the junction of the rectal mucosa and vestibular mucosa.
Figure 62-18. First stage of the two-stage repair of a third-degree perineal laceration. (A) The cranial-most extent of the rectovestibular shelf is incised in a horizontal plane. (B) The junction between the rectal mucosa and vestibular mucosa is delineated by a thin line of scar tissue. (C) Vestibular and rectal tissue flaps are created by dissecting along the line of scar tissue. (D) The vestibular mucosa is inverted into the vestibule using a continuous horizontal mattress pattern. The submucosal tissues are apposed using an interrupted pattern. (E) Completed first-stage repair.
Figure 62-19. Second stage of the two-stage repair of a third-degree perineal laceration. (A) The first-stage repair has healed and the mare is ready for the second stage of the repair. (B) The area of epithelialized tissue that is to be excised is outlined. (C) The submucosal tissues are apposed using interrupted purse-string sutures. This reconstructs the perineal body. (D) Completed second-stage repair.
Figure 62-20. Single-stage repair of a third-degree perineal laceration. Drawings show the use of a six-bite suture pattern to appose tissues
Figure 62-21. Rectovestibular fistula with manure contaminating the vestibule. Arrow points to the fistula.
Figure 62-22. Drawing showing dissection and repair of a rectovestibular fistula using the horizontal approach. (A) Completed dissection for repair of rectovestibular fistula. The fistula is divided into rectal and vestibular shelves. (B) The rectal shelf is sutured transversely. (C) The vestibular shelf is sutured longitudinally. (D) The rectovestibular fistula is repaired. The dead space created by the approach can now be closed.
Figure 62-23. Appearance of laceration at the dorsal aspect of the cervix during a speculum examination.
Figure 62-24. Photograph showing stay sutures placed to retract the cervix into the vestibule to facilitate repair. The sutures are placed to accentuate the defect in the cervix. Arrow points to the defect.
Figure 62-25. Appearance of a persistent hymen after it is exteriorized by an examiner.
