only be diagnosed as a pathologic condition when it consistently develops during natural mating (Figure 19.57) [4, 17, 21].
Figure 19.57 Spiral deviation.
Bulls with spiral deviation of the penis are most often three years old and have had a successful previous breeding season. Development of this condition may be insidious, occurring intermittently at first, then more consistently as breeding efforts continue. Therefore several test matings may be necessary to confirm the diagnosis. In B. indicus bulls the deviation may occur prior to penile extension such that the deviation remains hidden within the bull's pendulous sheath and excessive prepuce. For bulls with this sheath conformation, manual retraction of the prepuce during attempted breeding may be necessary to differentiate from erection or other causes of penile extension failure.
Ventral Penile Deviation
Ventral penile deviation occurs much less commonly than spiral deviation and the etiology is uncertain. Ventral deviations may occur as a result of altered blood flow through the ventral portion of the CCP or due to stretching or injury of the apical ligament, both of which probably result from chronic traumatic injury [1, 17, 18].
Ventral penis deviation is obvious as long gradual curvatures of the erect penis (Figure 19.58). The curvature frequently originates proximal to the junction of the sheath and prepuce [17, 18]. These conditions become more apparent as erection pressure increases. Because ventral penile deviation can be induced during electroejaculation, observation during natural breeding is recommended, especially for less obvious cases. These conditions are only considered to be pathologic when they consistently prevent intromission.
Figure 19.58 Ventral deviation.
Repair of Spiral and Ventral Penile Deviations
The prognosis for return to breeding soundness is greater following surgical repair of spiral than of ventral deviations. I recommend only attempting surgical repair of ventral deviations when the deviation is limited to the free portion of the penis. Spiral and ventral penile deviations are both repaired with a fascia lata graft. A narrow strip of fascia lata is sutured between the dorsal apical ligament and the dorsum of the tunica albuginea to serve as a fibroblast lattice to strengthen adjacent structures and stabilize the apical ligament on the dorsum of the penis [22].
Fascia Lata Graft Technique
This deviation as with those of a developmental etiology can be repaired with a fascia lata implant technique described by Walker and Young [22]. A rectangular strip of fascia is harvested from the bull, cleaned (areolar tissue removed), and placed between the apical ligament and the tunica albuginea. Alternatively, synthetic surgical mesh material can be used to substitute for the fascia implant. Utilization of the mesh has the obvious advantage of removing the time‐consuming fascia harvesting step. However, problems with postoperative infection with the mesh materials of the day along with dissatisfaction with the apical ligament “strip” technique were the impetus stated by Walker for the development of this technique [22]. Thus, the fascia lata technique will be described and those that prefer to can easily modify the technique to utilize surgical mesh.
The bull is fasted for 48 hours and water withheld overnight. Depending on his nature, the bull can be sedated with 10–20 mg xylazine and 10 mg acepromazine IV. With the bull restrained and standing, the surgical site, an area on the upper left hindlimb, is prepped, since the bull will later be placed in lateral recumbency on his right side. A local block utilizing an inverted L injection pattern is administered. A 15‐ to 20‐cm incision is then made utilizing the patella and greater trochanter as anatomical guides, with the incision being midway between. When the fascia lata is exposed, remove a rectangle‐shaped section. Removing a 3‐cm‐wide by 15‐cm‐long section will provide more than enough tissue for your graft (Figure 19.59). Place the tissue in saline, maintaining sterility, and suture the edges of the fascia with a continuous pattern utilizing any No. 1 or 2 dissolvable suture. Failure to do so will result in painful muscle herniation. The skin can be closed with No. 3 Braunamid utilizing a Ford interlocking pattern. The harvested tissue is prepared by rinsing in saline and removing any attached tissue (Figure 19.60).
Figure 19.59 Harvest of fascia.
Figure 19.60 Prepared fascia graft.
The bull is then prepared for the placing of this graft material. As with the other surgeries described, general anesthesia can be utilized or regional anesthesia with heavy sedation. The bull is tabled in right lateral recumbency and the preputial area is clipped and prepped. The penis is extended and the apical ligament identified and grasped with towel forceps. The penis is prepared with Betadine Surgical Scrub™, rinsed with sterile water or saline, and dried. Unlike when performing a circumcision, a tourniquet need not be utilized, as you will want to be able to easily visualize the area vasculature. An incision is made on the central dorsal aspect of the penis from a point 3 cm from the tip and extending 20 cm proximally. With careful dissection, identify the apical ligament and incise through it for its entire length. This incision will expose the tunica albuginea, and this is where the fascia or alternatively the synthetic mesh implant will be placed (Figure 19.61). The proximal aspect is placed first and sutures (2–0 chromic gut) are placed in the corners attaching the implant material to the tunic. Interrupted sutures are then placed on the lateral sides of the implant, stretching the implant so as to avoid crumpling of the tissue (Figure 19.62). Care is taken to not penetrate too deeply into the tunic and to avoid suture placement that impinges on the dorsal vasculature. The distal end of the implant is trimmed if necessary and the distal end is sutured as previously described.
Figure 19.61 Placement of fascia graft.
Figure 19.62 Suturing graft to tunic.
The edges of the apical ligament are closed utilizing 0 chromic gut, with every other or every third suture engaging the implant (Figure 19.63). This suture will keep the apical ligament from slipping to the side, which is crucial if correcting a spiral
