A newer and separate technique involves deposition of misprostol (PGE1) onto the oviductal papillae or utero‐tubular junction (UTJ) by deep horn uterine infusion, using a similar technique as a deep horn insemination (see Chapter 48). The procedure can be performed either during diestrus or estrus, and involves passing a long flexible insemination pipette to the tip of a uterine horn, followed by infusion of PGE1 in the region of the oviductal papilla. Ultrasound guidance can be utilized to confirm pipette placement, and the procedure is subsequently repeated in the opposite horn. Immediately following deposition of PGE1, the horn can be held off or the base of the horn lifted dorsad to promote diffusion of PGE1 onto each papilla.
The use of this technique has not been compared with other methods of treating oviductal obstructions or unexplained infertility. A recent clinical study reported 68.2% success rate in obtaining pregnancies or recovering embryos within two cycles following PGE1 treatment in a small subset of infertile mares. This result appears similar to other methods, with a primary advantage being much lower costs relative to laparoscopy or hydrotubation. Additional studies are needed to confirm the efficacy of PGE1 therapy for blocked oviducts or idiopathic infertility.
Equipment and Supplies
Misoprostol tablets (200 μg/tab; Cytotec®, Pfizer, Inc., New York, USA), sterile water, 12 ml syringe, deep horn insemination pipette, sterile obstetrical sleeves, examination gloves, obstetrical lube. Optional: ultrasound with 5 MHz rectal probe.
Technique
The mare is restrained appropriately and her tail wrapped (see Chapter 4).
The rectum is evacuated and the perineum prepared routinely for a clean vaginal procedure (see Chapter 3).
A 200 μg tablet of misoprostol is dissolved in 3 ml of sterile water and the solution drawn up into a sterile, long, flexible insemination pipette attached to a sterile 12 ml syringe.
Using a sterile obstetrical sleeve and sterile lubricant, the insemination pipette is passed through the cervix and directed up a uterine horn.
The arm is withdrawn from the vagina and is then placed in the rectum to direct the pipette up the tip of the horn. Note: transrectal ultrasound can be used to confirm location of pipette tip.
Once the tip of the pipette is in the proper location, the misoprostol solution is infused. During and immediately following infusion, the tip of the horn can be held off or the base of the horn can be elevated dorsad to assist the solution in coming into contact with the uterine tube papillae.
Once complete, the tip of the pipette is withdrawn from the horn and redirected up to the tip of the other horn, and additional PGE1 is deposited as previously described.
Evaluation of the mare the following day is highly recommended. Some mares may experience an inflammatory response to this treatment, necessitating the use of ecbolics and/or uterine lavage.
Additional Comments
The procedure can be performed in estrus or diestrus.
Mares can be bred or inseminated as early as the day after PGE1 infusion.
Further Reading
1 Allen WR, Wilsher S, Morris L, et al. 2006. Re‐establishment of oviductal patency and fertility in infertile mares. Anim Reprod Sci 94: 242–3.
2 Allen WR, Wilsher S, Morris L, et al. 2006. Laparoscopic application of PGE2 to re‐establish oviductal patency and fertility in infertile mares: a preliminary study. Eq Vet J 38: 454–9.
3 Alvarenga MA, Segabinazzi LG. 2018. Application of misprostol as a treatment of unexplained infertility in mares. J Eq Vet Sci 71: 46–50.
4 Bradecamp EA, Schnobrich MR. 2016. Hysteroscopic hydrotubation of the oviducts as a treatment for idiopathic infertility in the mare – a retrospective study. Proc Annu Conv Soc Theriogenol 8(3): 337.
5 Inoue Y. 2013. Hysteroscopic hydrotubation of the equine oviduct. Eq Vet J 45: 761–5.
6 Inoue Y, Sekiguchi M. 2017. Clinical application of hysteroscopic hydrotubation for unexplained infertility in the mare. Eq Vet J 50: 470–3.
7 Ortis HA, Foss RR, McCue PM, Bradecamp EA, Ferris RA, Hendrickson DA. 2013. Laparoscopic application of PGE2 to the uterine tube surface enhances fertility in selected subfertile mares. J Eq Vet Sci 33(11): 896–900.
8 Tsunami Y, Suzuki H, Takeda T, et al. 1979. Evidence of the origin of the gelatinous masses in the oviducts of mares. J Reprod Fertil 57: 287–90.
32 Hysteroscopic Hydrotubation of the Oviducts
Charles F. Scoggin
Rood and Riddle Equine Hospital, USA
Introduction
Hysteroscopic hydrotubation of the oviducts (uterine tubes) involves catheterizing the oviductal papillae (utero‐tubular junction) and flushing the oviducts in a retrograde fashion via endoscopic guidance. This technique is performed in confirmed or suspected cases of oviductal obstructions or in mares with unexplained infertility. Clinical studies in mares carrying their own pregnancy and embryo donors mares reported an ~80% success rate, in terms of either pregnancy or embryo recovery rates, within two cycles following the hydrotubation procedure.
In the author’s practice, this procedure is performed during diestrus or under the influence of progesterone when the cervix is tight to prevent air from escaping the uterine lumen during insufflation. It also requires a minimum of three experienced individuals: one person to pass the endoscope, another to drive the endoscope, and a third to operate the catheter and perform the flushing. The procedure is usually performed on each oviduct, after which the uterus is typically lavaged with lactated Ringer’s solution (LRS) and the mare administered a luteolytic dose of prostaglandin F2α. Treatment with antibiotics and anti‐inflammatory drugs may also be performed at the discretion of the clinician. Follow‐up therapy with daily lavages for 1–3 days post‐hydrotubation is recommended to reduce the risk of iatrogenic endometritis.
Equipment and Supplies
Sedation, previously sterilized 1 or 1.5 m flexible videoendoscope, 200 cm (79 inch) polyethylene tube with 1.7 mm OD (Hibiki high class grade size 5) with a 22 gauge 2.45 cm (1 inch) injection catheter attached to one end, 0.46 diameter and 220 cm (87 inch) long angiocatheter guidewire (Nit‐Vu® Angiodynamics®, Latham, New York, USA), 12 ml plastic syringes, 20 g × 4 cm (1.5 inch) needles, sterile obstetrical sleeves, examination gloves and sterile obstetrical lubricant, lactated Ringer’s solution, uterine lavage tubing, prostaglandin F2α.
Technique
The mare is placed
