Fibro-Osseous Lesions Of The Craniofacial Complex In Horses: 30 Cases (2001-2019).

OBJECTIVE: To describe the presentation, diagnosis, treatment, and outcome for horses with fibro-osseous lesions of the craniofacial complex. STUDY DESIGN: Retrospective multicenter case series. ANIMALS: Thirty horses evaluated for fibro-osseous lesions of the skull from January 1, 2001 through December 31, 2019 in four centers. METHODS: Medical records were reviewed for signalment, clinical presentation, histological and diagnostic imaging findings, treatment instituted, and outcome. Long-term outcome information was obtained by owner questionnaire or the medical record. RESULTS: Diagnoses included ossifying fibroma in 20 of 30 horses, osteoma in eight of 30 horses, and fibrous dysplasia in two of 30 horses. Twelve of 30 lesions were diagnosed in horses <1 year old, and 20 of 30 lesions originated from the rostral mandible. The most common treatment was rostral mandibulectomy. Recurrence was not reported after complete excision. Incomplete excision was confirmed in eight horses (four ossifying fibromas, three osteomas, and one fibrous dysplasia), and follow-up information was available for seven horses. Recurrence occurred in one horse, while six horses had long-term resolution of clinical signs. Prognosis for survival and return to use was excellent in 23 horses with long-term follow-up. CONCLUSION: Fibro-osseous lesions were uncommon in this multicenter study; they were most commonly diagnosed in young animals and most frequently affected the rostral mandible. Long-term survival was excellent. CLINICAL SIGNIFICANCE: The definitive diagnosis of fibro-osseous lesions of the craniofacial complex in horses is made from results of histopathology and cannot be determined on the basis of clinical presentation alone. Surgical excision is indicated, and prognosis can be favorable even when complete surgical margins are not obtained.

Impact of alpha-tocopherol deficiency and supplementation on sacrocaudalis and gluteal muscle fiber histopathology and morphology in horses.

BACKGROUND: A subset of horses deficient in alpha-tocopherol (α-TP) develop muscle atrophy and vitamin E-responsive myopathy (VEM) characterized by mitochondrial alterations in the sacrocaudalis dorsalis medialis muscle (SC). OBJECTIVES: To quantify muscle histopathologic abnormalities in subclinical α-TP deficient horses before and after α-TP supplementation and compare with retrospective (r)VEM cases. ANIMALS: Prospective study; 16 healthy α-TP-deficient Quarter Horses. Retrospective study; 10 retrospective vitamin E-responsive myopathy (rVEM) cases . METHODS: Blood, SC, and gluteus medius (GM) biopsy specimens were obtained before (day 0) and 56 days after 5000 IU/450 kg horse/day PO water dispersible liquid α-TP (n = 8) or control (n = 8). Muscle fiber morphology and mitochondrial alterations were compared in samples from days 0 and 56 and in rVEM cases. RESULTS: Mitochondrial alterations more common than our reference range (<2.5% affected fibers) were present in 3/8 control and 4/8 treatment horses on day 0 in SC but not in GM (mean, 2.2; range, 0%-10% of fibers). Supplementation with α-TP for 56 days did not change the percentage of fibers with mitochondrial alterations or anguloid atrophy, or fiber size in GM or SC. Clinical rVEM horses had significantly more mitochondrial alterations (rVEM SC, 13% ± 7%; GM, 3% ± 2%) and anguloid atrophy compared to subclinical day 0 horses. CONCLUSIONS AND CLINICAL IMPORTANCE: Clinically normal α-TP-deficient horses can have mitochondrial alterations in the SC that are less severe than in atrophied VEM cases and do not resolve after 56 days of α-TP supplementation. Preventing α-TP deficiency may be of long-term importance for mitochondrial viability.

Outcome following computed tomographic imaging and subsequent surgical removal of keratomas in equids: 32 cases (2005-2016).

OBJECTIVE To describe the use of CT in the diagnosis of and presurgical planning for equids with keratomas treated by hoof wall resection and determine postoperative complications and outcome. DESIGN Retrospective case series. ANIMALS 29 horses and 3 mules with keratomas treated by partial or complete hoof wall resection following CT imaging of the distal portion of the affected extremity from 2005 through 2016. PROCEDURES For each equid, physical examination and lameness evaluation were performed, followed by imaging of the distal portion of the affected extremity. A tentative diagnosis of keratoma was made given results of clinical, radiographic, and CT examination, with the definitive diagnosis made on histologic examination. After CT imaging, each equid was treated with hoof wall resection. RESULTS CT allowed accurate identification of the size and location of 35 keratomas in 33 feet. Thirty equids underwent partial and 2 underwent complete hoof wall resection for keratoma removal. Complications developed in 4 of 31 (13%) equids and included excessive granulation tissue formation at the surgical site (n = 1), excessive granulation tissue formation and worsening lameness (1), incomplete keratoma removal with suspected regrowth (1), and incomplete healing of the surgical site with distal interphalangeal joint sepsis secondary to repeated debridement of abnormal tissue (1). Twenty-eight of 31 (90%) equids returned to their previous activity level. CONCLUSIONS AND CLINICAL RELEVANCE Preoperative CT examination of the feet was useful in the diagnosis of and surgical planning for keratomas in equids. A low complication rate was achieved with the described techniques.

Use of a locking compression plate for equine proximal interphalangeal joint arthrodesis: 29 cases (2008-2014).

OBJECTIVE To describe clinical use of a locking compression plate (LCP) for proximal interphalangeal joint (PIPJ) arthrodesis in horses and compare outcomes for horses that underwent the procedure as treatment for fracture of the middle phalanx (P2) versus other causes. DESIGN Retrospective case series. ANIMALS 29 client-owned horses. PROCEDURES Medical records of 2 veterinary teaching hospitals from 2008 through 2014 were reviewed to identify horses that underwent PIPJ arthrodesis of 1 limb. Signalment, surgical, and outcome-related variables were recorded. Owners were contacted from 1 to 6 years after surgery to determine rehabilitation time, current use of the horse, and overall owner satisfaction with the procedure. Success was determined on the basis of owner satisfaction and outcome for intended use. Variables of interest were compared statistically between horses that underwent surgery for P2 fracture versus other reasons. RESULTS 14 horses underwent surgery for treatment of P2 fracture, and 15 had surgery because of osteoarthritis, subluxation, or osteochondrosis. Median convalescent time after surgery (with no riding or unrestricted exercise) was 7 months. Four horses were euthanized; of 23 known alive at follow-up, 22 were not lame, and 18 had returned to their intended use (8 and 10 at higher and lower owner-reported levels of work, respectively). Horses undergoing arthrodesis for reasons other than fracture were significantly more likely to return to their previous level of work. Twenty-two of 24 owners contacted indicated satisfaction with the procedure. CONCLUSIONS AND CLINICAL RELEVANCE Surgical arthrodesis of the PIPJ was successful in most horses of the study population. Various nuances of the system for fracture repair need to be understood prior to its use.

A novel ultrasonographic assisted technique for desmotomy of the palmar/plantar annular ligament in horses.

OBJECTIVES: To describe an ultrasound assisted technique for desmotomy of the palmar/plantar annular ligament (PAL), determine its efficacy and intraoperative complications. STUDY DESIGN: Cadaveric and in vivo study. ANIMALS: Cadaveric limbs (n = 12), adult horses (n = 4), and clinical cases (n = 2). METHODS: Ultrasound assisted desmotomy of the palmar/plantar annular ligament (UAD-PAL) was performed in cadaveric limbs and in standing horses with the operated limb placed in a distal limb splint. The procedure was performed under general anesthesia and was followed by tenoscopic examination in 2 clinical cases. A hook knife was developed for the procedure. Complete transection was assessed by postmortem dissection (10 forelimbs, 10 hindlimbs) and tenoscopic examination (1 forelimb, 1 hindlimb). Thickness of PAL, surgery time, other intraoperative parameters and complications associated with the procedure were recorded. RESULTS: Complete PAL transection was accomplished in 20/22 limbs. No iatrogenic damage to adjacent intrathecal structures was identified in any case. The instrument was correctly positioned on the first attempt in 19/22 cases. The most common intraoperative complication was inadvertent subcutaneous placement of the instrument (n = 2). Significant thickening of the PAL (3 mm) was present in 1/2 limbs in which complete transection was not achieved. CONCLUSIONS: UAD-PAL with the custom-made hook knife was effective at transecting the PAL with minimal intraoperative complications. The procedure can be performed in standing sedated horses. Another method should be considered in horses with thickened PAL.

Use of a laparoscopic specimen retrieval pouch to facilitate removal of intact or fragmented cystic calculi from standing sedated horses: 8 cases (2012-2015).

OBJECTIVE To evaluate the use of a laparoscopic specimen retrieval pouch for removal of intact or fragmented cystic calculi from standing horses. DESIGN Retrospective case series. ANIMALS 8 horses (5 geldings and 3 mares) with cystic calculi. PROCEDURES Physical examination and cystoscopic, ultrasonographic, and hematologic evaluations of urinary tract function were performed for each horse. A diagnosis of cystic calculus was made on the basis of results of cystoscopy and ultrasonography. Concurrent urolithiasis or other urinary tract abnormalities identified during preoperative evaluation were recorded. Horses were sedated and placed in standing stocks, and the perineum was aseptically prepared. Direct access to the urinary bladder was gained in geldings via perineal urethrotomy or in mares by a transurethral approach. Calculi were visualized endoscopically, manipulated into the retrieval pouch, and removed intact or fragmented (for larger calculi). RESULTS For 4 geldings and 1 mare, fragmentation was necessary to facilitate calculus removal. Mean duration of surgery was 125 minutes, and trauma to the urinary bladder and urethra was limited to areas of hyperemia and submucosal petechiation. No postoperative complications were encountered for any horse. When lithotripsy was required, the retrieval pouch provided an effective means of stabilizing calculi and containing the fragments for removal. CONCLUSIONS AND CLINICAL RELEVANCE Use of the laparoscopic specimen retrieval pouch was an effective, minimally traumatic method for retrieving cystic calculi from standing horses. The pouch protected the urinary bladder and urethra from trauma during calculus removal and allowed for stabilization, containment, and fragmentation of calculi when necessary.