In a study using laparoscopy, fluorescent beads were recovered from the uterus of 86% of mares with oviducts without plugs (determined by flushing excised oviducts at necropsy) as compared with only 29% of mares with oviducts containing plugs. Interestingly, 92.8% of oviducts contained beads of both colors, suggesting intraperitoneal bead movement. Ultimately, the study noted a 71.4% ability of the test to correctly detect a mare with plugs (test sensitivity) and an 85.7% ability of the procedure to correctly detect a mare without plugs (test specificity). The absence of fluorescent beads in the uterine lumen is suggestive of, but not conclusive evidence for, a blocked oviduct.
As with the starch granule test, the diameter of the microspheres used in the published studies are considerably smaller, at 15 μm, than an oocyte or early developing oviductal stage embryo (150–250 μm) and may not be the ideal size for the detection of a mass that would impede embryo transport distally through the isthmus and into the uterus.
Transvaginal deposition may result in a variable amount of beads entering the infundibulum; whereas, laparoscopic cannulation results in more accurate placement of beads. Laparoscopic deposition does, however, require a certain technical skill and specialized equipment. Laparoscopic deposition of beads also allows for direct observation of the oviduct. Mares with oviductal pathology may exhibit oviductal swelling, and an increase in vascularity or adhesions.
Further Reading
1 Arnold CE, Love CC. 2013. Laparoscopic evaluation of oviductal patency in the standing mare. Theriogenology 79: 905–10.
2 Kollmann M, Rotting A, Heberling A, Sieme H. 2011. Laparoscopic techniques for investigating the equine oviduct. Eq Vet J 43: 106–11.
3 Ley WB, Bowen JM, Purswell BJ, et al. 1998. Modified technique to evaluate uterine tubal patency in the mare. Proc Annu Conv Am Assoc Eq Pract 44: 73–104.
29 Oviductal Flush Procedure for the Evaluation of Oviductal Patency
Sofie Sitters1 and Patrick M. McCue2
1 Amsterdam, The Netherlands
2 Equine Reproduction Laboratory, Colorado State University, USA
Introduction
Blockage of one or both oviducts with intraluminal gelatinous mases consisting of a mixture of collagen, fibroblast cells, and other debris, can result in reduction of fertility in the mare. Access to the oviduct for both diagnostic and therapeutic purposes is limited. As discussed in Chapters 27 and 28, both the diagnostic starch granule test and the fluorescent microspheres test have their limitations for the evaluation of oviductal patency in the mare and neither method treats a potentially blocked oviduct.
Flushing of the oviduct has been performed as both a diagnostic and a therapeutic procedure. Techniques have included retrograde flushing from the utero‐tubular junction (UTJ) proximally toward the infundibulum and normograde flushing from the infundibulum distally toward the uterus using either a standing flank laparoscopic or ventral midline laparotomy approach. In addition, retrograde flushing of the oviduct via the UTJ is possible using a standing hysteroscopic approach (see Chapter 32).
Oviductal flush techniques are reserved for mares that have a prolonged history of infertility, with good breeding management, bred to fertile stallion(s), and that have no other significant reproductive abnormalities noted during a breeding soundness evaluation.
Retrograde 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 after surgery as needed.
The mare is placed under general anesthesia and in dorsal recumbency.
The ventral abdomen is clipped free of hair.
A standard surgical prep is made over the ventral abdomen.
Two paramedian incisions are made in the caudal ventral abdomen through the skin and blunt dissection is used to pass through the external and internal abdominal oblique muscles.
A hand is passed into the abdomen and the adjacent ovary and uterine horn tip are exteriorized.
A small incision is made near the uterine horn tip and the uterus is everted to expose the papilla of the UTJ.
The papilla is cannulated with the blunt‐ended catheter.
The oviduct is flushed retrograde with sterile saline containing fluorescein dye.
The infundibulum end of the oviduct is observed for the presence of colored saline which may contain masses.
The procedures are repeated on the contralateral oviduct.
The uterus and abdomen are closed in a routine manner.
Comments
Cannulation of the papilla of the UTJ is technically difficult to perform. The original paper (Zent et al. 1993) indicated that the flush procedure was successful in five of eight mares, with oviductal masses observed in the flush fluid from both oviducts in all five mares. Three of the mares eventually had live foals. Note that the retrograde oviductal flush is also possible via a hysteroscopic approach in the standing mare.
Equipment and Supplies
Antibiotics, non‐steroidal anti‐inflammatory drugs, sedation, local anesthetic, and general anesthesia use vary with each procedure.
Retrograde oviductal flush, laparotomy approach
Surgical scrub, examination gloves, clippers, standard surgical supplies for abdominal surgery, sterile saline, 1.3 cm (0.5 inch) 24 gauge blunt‐ended catheter, fluorescein dye (add one fluorescein ophthalmic strip to 10 ml of sterile saline), 12 ml syringe.
Normograde oviductal flush, laparotomy approach
Surgical scrub, examination gloves, clippers, standard surgical supplies for abdominal surgery, Doyen intestinal forceps, 8.0 Fr Foley catheter 30 cm (12 inch) with 5.0 ml balloon cuff (no. V‐PFC8‐30; Cook Veterinary Products, Inc., Bloomington, IN, USA), sterile saline, new methylene blue dye, 20 ml syringe.
Normograde oviductal flush, laparoscopic approach
Standard equipment and supplies for a standing laparoscopic surgery: detomidine hydrochloride, butorphanol tartrate, laparoscopic Babcock forceps or oviductal forceps (×2), 7 Fr balloon catheter (Willy Rűsch GmbH, Kernen i.R., Germany), sterile saline, methylene blue dye, 20 ml syringe, videoendoscope to evaluate the uterine lumen after the flush procedure.
Retrograde oviductal flush, hysteroscopic approach
Examination gloves, tail wrap, tail rope, non‐irritant soap, bucket, disposable bucket liner, roll cotton, sterile surgical gloves, long sterile sleeves, indigo carmine solution (5 ml, 4 mg/ml indigo carmoine injection), oviduct catheter: 200 cm (79 inch) polyethylene tube (1.7 mm OD) with a 22 gauge 4.45 cm (1.75 inch) injection catheter attached at one end and a 20 gauge 3.8 cm (1.5 inch) needle connected to a 5 ml syringe (filled with dye) at the opposite end, guidewire for human angiography