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Rectricectomy With Pygostylectomy for Resolution of Feather Trauma in an Umbrella Cockatoo (Cacatua alba).

Abstract: Feather trauma is a common problem among pet birds, especially those with trimmed wing feathers, and often affects remiges and rectrices. Damage can become chronic if new feathers remain unprotected by fully formed adjacent feathers. The follicles can become damaged and poorly functional over time. A 6-month-old male umbrella cockatoo (Cacatua alba) was presented for examination because of feather damage that occurred shortly after receiving a wing trim by the owner. Over the next 18 months, various medical, behavioral, and husbandry methods failed to allow normal regrowth of the tail feathers. The bird presented 25 times over the 18-month period for problems associated with broken blood feathers in the tail. Feather imping was ruled out because of the lack of hollow adult shafts to serve as a base. Diagnostic tests included hematologic testing and biochemical analysis, circovirus testing, feather biopsy, and radiographs, results of which were unremarkable. Because of the chronic pain associated with the frequent rectrix damage, a complete rectricectomy was performed. All of the rectrical follicles as well as the pygostyle were surgically removed. Healing was uneventful and the bird has been clinically normal with no further blood feather injury for 24 months after surgery.

Key words: rectrix, rectrices, blood feather, surgery, trauma, feather, follicle, avian, umbrella cockatoo, Cacatua alba

Clinical Brief

A 6-month-old male umbrella cockatoo (Cacatua alba) was presented to the Zoological Medicine Service, University of Illinois Veterinary Teaching Hospital, because of feather damage that occurred shortly after receiving a wing trim by the owner. The bird's previous history included a periesophageal granuloma secondary to an esophageal puncture that had been surgically corrected 3 months before the current presentation. Although wing trimming had been requested during hospitalization for the esophageal puncture, the owner was advised to maintain full wing feathers, at least until the bird had developed normal flight capabilities. Alternate means of controlling flight, such as harness training, were discussed. Unfortunately, the owner did not comply with this recommendation. The diet and other husbandry issues were deemed appropriate.

Physical examination revealed that all of the primary and secondary remiges had been clipped by the owner. The tertiary remiges had been chewed by the bird to the same length as the cut feathers. All of the rectrices had fractured; some had the distal fragment hanging down from the base, others had been chewed off. No other abnormalities were observed. Results of a complete blood count and plasma biochemical analysis were unremarkable.

At this time, the owner was given instructions for enrichment, including foraging and positive-reinforcement training. Advice regarding prevention of further trauma was also discussed, including lower placement of perches, padding the cage bottom and surrounding areas, and interacting with the bird on the floor. Some of these suggestions proved difficult for the owner to implement because, despite the damaged tail feathers, the bird was very active.

Over the next several months, the damaged wing feathers were replaced via molting and were no longer traumatized by the bird. The owner insisted on continued wing trimming, but this was done more conservatively by the veterinary staff. Throughout this time, the tail feathers would repeatedly break during the blood feather stages. When this occurred, the bird was presented to the emergency services, where the broken blood feathers were removed, until the emergency staff was instructed to avoid removing the broken feathers unless approved by the zoological medicine staff. In total, the bird was presented 25 times over an 18-month period to either the zoological or the emergency service for problems associated with damaged rectrices. During this time, diagnostic tests included hematologic testing and biochemical analysis, serologic testing for circovirus, and histopathologic examination of the feather follicles. Results of blood tests were within reference ranges, and circovirus test results were negative. Histopathologic results revealed necrosis and lymphocytic inflammation, but no viral, bacterial, or other infectious agents were identified.

Medical treatment included antimicrobial therapy, analgesics, and a tricyclic antidepressant. Trimethoprim/sulfamethoxazole (48 mg/kg PO q12h) and enrofloxacin (15 mg/kg PO q12h) were used for 2-week periods at different times. Both butorphanol (1 mg/kg IM once at the time of blood feather removal) and meloxicam (0.5 mg/kg PO q12h as needed) were used at various times for pain relief. Although the bird's behavior was calm and appropriate in the clinic, the owner described more anxious behavior at times at home. For this reason, a trial of clomipramine (3 mg/kg PO q24h) was initiated. Although the anxious behavior appeared to decrease slightly over the next 2 months, the tail feathers did not improve. More aggressive treatments were discussed at this time. A tail guard was secured to the tail with some difficulty because of the lack of intact feathers. The guard remained intact for approximately 2 months, with no signs that the bird had traumatized the guard or the feathers beneath it. Despite this, no tail feathers progressed to the point where they plumed into adult feathers. Feather imping was ruled out because of the lack of hollow adult shafts to serve as a base. Because of the presumed chronic pain associated with the frequent rectrix damage, the decision was made to perform a complete rectricectomy.

At surgery, butorphanol (1 mg/kg IM) was administered preoperatively. After mask induction with isoflurane, a 3.0-mm endotracheal tube was placed and used for anesthetic maintenance. Feathers proximal to the rectrices were plucked to create a surgical field (Fig 1). After surgical preparation and draping, an incision was made by radiosurgery just proximal to the openings for the rectrices, both dorsally and ventrally (Fig 2). The skin was reflected proximally by blunt and sharp dissection, revealing the proximal base of the rectrical follicles (Fig 3). During dissection, a small nick was inadvertently made in the deep, ventral aspect of the uropygial gland. This was cleansed and sutured with 5-0 polydioxanone suture (PDS, Ethicon, Somerville, NJ, USA) in a continuous pattern. The attachments of the follicles were severed from lateral to medial by radiosurgical dissection. Because the first rectrix on each side was firmly attached to the pygostyle, this bone was disarticulated from the tail and removed with the rectrices, which were removed in 1 fan-like piece (Fig 4). Bleeding was minimal and controlled with radiocoagulation and direct pressure. A splash block of 0.5% bupivacaine (1 mg/kg) and 2% lidocaine (1 mg/kg) was applied to the surgical site. The skin edges were trimmed to provide smooth edges and were closed with 4-0 PDS in a simple interrupted pattern (Fig 5). Butorphanol (1 mg/kg intranasally q4-8h) was continued after surgery for 2-3 days. Meloxicam was prescribed for 10 days at the previous dosage. Clomipramine treatment was continued.

Histopathologic examination of the rectrices revealed mild acute hemorrhage but no other disease processes. At recheck 16 days after surgery, the incision was healing well with no evidence of complications (Fig 6). After another 3 weeks, the incision was completely healed, covert feathers had regrown, and the tail formed a tapered point (Fig 7). In the 2 years since the surgery, the bird has been examined for regular wellness visits. Although covert feathers are occasionally dystrophic, no broken blood feathers have been reported in this time. The bird remained on clomipramine orally, as the owner reports the bird exhibits agitation when the dose is tapered. Despite the problems resulting from the initial wing trim, the owner insisted on continued wing trims after the tail amputation. However, wing trimming was done as conservatively as possible to avoid further problems.

Discussion

Feather trauma is a common problem among pet birds. The combination of cage confinement, poor coordination, wing trimming, and feather-damaging behavior may result in a variety of feather injuries. Often these injuries are primarily cosmetic, but when large blood feathers are involved, hemorrhage, pain, and eventually follicular damage affecting the growth of the replacement feathers can result. When remiges and rectrices are involved, this can result in chronically painful wings and tails, with feathers that cannot regrow because each new feather is unprotected by a fully formed adjacent feather. The loss of retrices and remiges in turn can increase the risk of falling or abnormal flight, furthering the chance of continued trauma. Over time, the follicles may become damaged and poorly functional. These factors should be carefully considered before trimming the wings of a bird. In particular, trimming the wing feathers before fledging, or trimming the wing feathers excessively, carries a high risk of potential harm, as was seen in this case. These risks should be discussed with owners to discourage them from trimming the feathers on their own.

Feather trauma creates a challenging clinical problem in pet birds. The management of these conditions can include a variety of behavioral, pharmacologic, and management techniques. When the feathers are mature and the shaft is healthy and hollow, feather imping is a helpful technique. (1,2) However, a feather that is in a blood feather stage cannot accept a donor feather. The use of tail guards is common in raptors in wildlife facilities. This helps maintain the integrity of the retrices until the bird is no longer confined. This proved difficult with the bird in this case. Tail guards are taped to the base of the rectrices to hold the guard in place. The tail of cockatoos is relatively short, and the feathers of this bird were all in blood feather stage, precluding adequate adhesion of the tail guard. The tail guard then had to be sutured to the skin. The guard did serve the purpose of protecting the tail; no broken feathers occurred while it was in place. However, in this case, the feathers failed to mature during the time the tail guard was in place. The feathers never developed barbs or plumed out from their sheaths. Whether this was caused by the feather guard constantly rubbing against the feathers or by damaged feather follicles is not known. However, no significant progress in the feather development occurred after about 2 months with the tail guard in place.

Amputation of the tail has been described in birds, primarily for neoplastic conditions. (3) In this cockatoo, the rectrices were damaged but not neoplastic, so large surgical margins were not necessary. For this reason, removal of the feather follicles was thought to be sufficient. Ultimately, the pygostyle was amputated as well; therefore, this surgical procedure could also be considered a distal tail amputation. However, because most of the tail remained intact, the term rectricectomy with pygostylectomy likely more accurately describes the purpose and application of the technique. The procedure resulted in resolution of the frequent tail feather trauma and an acceptable cosmetic appearance. This particular bird was kept with clipped wing feathers, so the functionality of the tail in flight could not be assessed. It could be expected that the ability to change directions, slow down, and land would be affected by the loss of the surface area of the rectrices. This technique is not appropriate for wild birds or those for which flight is necessary. The bird in this case never attempted to mutilate the tail guard or the incision after the rectricectomy was performed. However, this could present a problem in some birds, especially in cases where a bird is traumatizing the feathers with its beak. Effective pain management may help to prevent this. The use of an Elizabethan collar or other restraint device may also help to prevent trauma, but these devices are often quite stressful for the bird. For this reason, no restraint devices were used in this case. Although rectricectomy is an extremely aggressive technique with very limited application, it may be a viable surgical option for resolution of specific cases of chronic tail feather trauma when more conservative measures have failed.

References

(1.) Welle KR. Application of feather imping in psittacine birds. Proc Annu Conf Assoc Avian Vet. 1998:227 229.

(2.) Lierz M, Fischer D. Clinical technique: imping in birds. J Exotic Pet Med. 2011:20(2): 131-137.

(3.) Olsen G. Resolution of an undifferentiated pygostyle squamous cell carcinoma by tail amputation. Proc Annu Conf Assoc Avian Vet. 2009:345.

Kenneth R. Welle, DVM, Dipl ABVP (Avian)

From the University of Illinois. College of Veterinary Medicine, 1008 W Hazelwood Dr. Urbana. IL 61802. USA.

Caption: Figure 1. The tail of an umbrella cockatoo with a chronic history of feather damage to the retrices. The tail area was prepared for surgery by removing the covert and down feathers. The rectrices were left in place to provide visibility of the follicles as well as to provide a handle to manipulate the follicles. Note the dystrophy of many of the feathers.

Caption: Figure 2. The cockatoo described in Figure 1. An incision was made with bipolar radiosurgery to minimize hemorrhage. The incision was made as distally as possible to maximize the available skin for closure.

Caption: Figure 3. The cockatoo described in Figure 1. The tips of the follicles (white arrows) are visible after dissection.

Caption: Figure 4. The cockatoo described in Figure 1. (a) The vessels entering the inferior umbilicus were coagulated and the attachments severed, (b) The first rectrix on each side was firmly attached to the pygostyle, which also extends to the very tip of the tail, making closure difficult. For this reason, the pygostyle was removed with the rectrices. (c) The rectrices were removed as a single unit, interconnected by numerous ligaments.

Caption: Figure 5. The cockatoo described in Figure 1 after removing the retrices and pygostyle. (a) The skin was trimmed to provide a smooth edge for closure, (b) The skin was closed with 4-0 PDS in a simple interrupted pattern.

Caption: Figure 6. The cockatoo described in Figure 1. The incision was healing well at 16 days after surgery.

Caption: Figure 7. The cockatoo described in Figure 1. Without the rectrices, the tail is now tapered to a short point.
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Title Annotation:Clinical Brief
Author:Welle, Kenneth R.
Publication:Journal of Avian Medicine and Surgery
Date:Jun 1, 2019
Words:2306
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