Optional (vaginotomy)
Scalpel, second sterile flexible endoscope.
Normograde Oviductal Flush (Laparotomy Approach) Technique
Performed under general anesthesia.
The mare is fasted for 24 hours prior to surgery.
Antibiotics and flunixin meglumine (1.1 mg/kg IV, s.i.d.) are administered prior to surgery and for 3 days after surgery.
The mare is placed under general anesthesia and in dorsal recumbency and a pelvic tilt apparatus applied to gain better access to the reproductive tract.
The ventral abdomen is clipped free of hair.
A standard surgical prep is made over the ventral abdomen.
A 10 cm incision is made along the ventral midline just cranial to the udder.
One ovary and uterine horn are exteriorized and examined for gross pathology.
Doyen intestinal forceps are placed on the uterine horn 5 cm from the cranial tip to occlude the uterine horn.
An 8.0 Fr balloon‐tipped catheter is passed into the infundibulum of the oviduct and down to the ampulla region and the cuff inflated with approximately 1.0–1.5 ml of air.
20 ml of sterile saline with new methylene blue dye is slowly injected through the catheter as the catheter is held in the oviduct by the application of manual pressure proximal to the balloon.
Patency of the oviduct may be confirmed by the techniques below:Injection and aspiration of 10–20 ml of sterile saline into the occluded cranial uterine horn to detect the presence of dye.Injection of 20 ml of air through the catheterized oviduct and listening for the sound of air “gurgling” through the UTJ into the uterine lumen.The advantage of performing these confirmation procedures is that additional flushing could be performed if the oviduct is not yet patent.Alternatively, an endoscopic examination of the uterine lumen could be used to visualize the dye. This could be accomplished by a second set of personnel during surgery while the horse is under general anesthesia.
The procedures are repeated on the contralateral oviduct.
The abdomen is closed in a routine manner.
Comments
Oviductal lavage may cause dislodgment of oviductal blockages and may therefore be therapeutic. Caution should be used to not overly dilate the oviduct or exert excessive pressure. Severely occluded oviducts may rupture during the flush procedure. A unilateral ovariectomy may be performed in the event of irreversible occlusion or oviductal rupture. An initial report (Bennett et al. 2002) using this technique noted that eight of 12 mares diagnosed with bilateral occlusions and five of six mares with unilateral oviductal occlusion became pregnant on the first cycle after the flush procedure.
Normograde Oviductal Flush (Laparoscopic Approach) Technique
Standing procedure.
The mare is fasted for 24 hours prior to surgery.
Antibiotics and flunixin meglumine (1.1 mg/kg, IV, s.i.d.) are administered prior to surgery and after surgery as needed.
The mare is appropriately sedated; additional sedation may be required and administered as needed. In the original paper a combination of detomidine hydrochloride (0.01 mg/kg, IV) and butorphanol tartrate (0.01 mg/kg, IV) were administered.
The paralumbar fossa is prepared for laparoscopic surgery.
A local anesthetic is placed into the locations for the portal sites.
Three instrument portals are created and one portal for the laparoscope (Figure 29.1). The abdomen is insufflated with CO2 to allow for visualization of the internal abdominal structures.
A pair of laparoscopic Babcock forceps or oviductal forceps are used to grasp and open the edges of the infundibulum to view the ostium of the oviduct.
The balloon catheter is inserted into a guide sleeve and passed into the ostium and advanced distally toward the ampulla.
The cuff is inflated with 1.0–1.5 ml of air.
One Babcock forceps is removed from the infundibulum and repositioned behind the balloon cuff to secure the catheter in place during the flush procedure
The oviduct is flushed with 20 ml of sterile methylene blue solution.
The procedure is subsequently performed on the contralateral oviduct.
Hysteroscopy to visualize the oviductal papilla is performed during the flush to determine if the dye solution passed through each oviduct into the uterus.
The portal incisions are closed in a routine manner.
Figure 29.1 Landmarks for instrument portals: 1 is the laparoscopic portal; 2 and 3 are locations for the portals for the forceps; and 4 is the portal for the guide sleeve and catheter.
Comments
The original paper (Köllmann et al. 2011) compared flank laparoscopy with a transvaginal laparoscopic approach. The transvaginal approach was not successful and consequently is not discussed in this chapter. The major advantages of the laparoscopic procedure as compared with laparotomy are elimination of the need for general anesthesia and a minimally invasive approach. Disadvantages include costs of laparoscopic equipment and the clinical expertise needed to perform the procedure.
Additional Comments
Overall, flushing the oviducts provides diagnostic information on oviductal patency and at the same time often provides therapeutic intervention in affected mares. In regard to the latter, it has been suggested that removing oviductal masses via the normograde approach may be more difficult compared with the retrograde approach, as the luminal diameter of the isthmus is significantly smaller than the ampulla.
A concern for all the approaches discussed is the need to provide significant pressure during the flush to successfully relieve blockage(s) without rupturing the oviduct. It may be possible to reduce the risk by systemic administration of N‐butylscopolammonium bromide and/or local application of prostaglandin E2 gel onto the surface of the oviduct or the UTJ prior to the flush.
To avoid this risk of rupture of the oviduct altogether, the purely therapeutic option of applicating PGE2 to either the oviductal surface or the UTJ (without first checking oviductal patency) can also be considered in mares suspected of having oviductal issues (see Chapters 30 and 31).
References
1 Bennett SD, Griffin RL, Rhoads WS. 2002. Surgical evaluation of oviduct disease