Morphine Synovial Fluid Concentrations After Intravenous Regional Limb Perfusion in Standing Horses.

OBJECTIVE: To determine synovial concentrations of morphine after intravenous regional limb perfusion (IVRLP) with morphine or morphine in combination with gentamicin in clinically healthy, standing sedated horses. STUDY DESIGN: Experimental. ANIMALS: Adult horses (n = 6). METHODS: IVRLP was performed using 0.1 mg/kg morphine (M) in standing sedated horses. After a 3-week washout period, IVRLP was performed on the same forelimb with a combination of 0.1 mg/kg morphine and 1 g gentamicin (M/G). Synovial fluid from the middle carpal joint of the perfused limb and jugular blood samples were collected immediately before each perfusion and 20 minutes, and 2, 8, and 24 hours after IVRLP. Morphine and gentamicin concentrations were determined by ELISA. Data were assessed using 2-way repeated measures ANOVA with significance set at P ≤ .05. RESULTS: Synovial fluid morphine concentrations were greatest 20 minutes after perfusion. Mean ± SD peak synovial morphine concentrations over 12 perfusions were 3903 ± 4881 ng/mL. There was no significant difference in morphine synovial concentrations after M or M/G. Plasma morphine concentrations peaked within 2 hours of perfusion (range, 11-63 ng/mL). Mean peak gentamicin concentrations in synovial fluid were 76,315 ± 39,809 ng/mL. IVRLP morphine did not cause clinically apparent adverse effects. CONCLUSIONS: IVRLP in standing sedated horses results in measurable levels of morphine in synovial fluid and synovial concentrations of gentamicin after perfusion in combination with morphine are equivalent to those previously reported.

Tiludronate concentrations and cytologic findings in synovial fluid after intravenous regional limb perfusion with tiludronate in horses.

Anecdotal accounts of tiludronate administration via intravenous regional limb perfusion (IVRLP) exist despite a lack of information regarding safety for synovial structures in the perfused area. The objective of this study was to determine whether tiludronate concentrations in synovial structures after IVRLP with low dose (0.5 mg, LDT) or high dose (50 mg, HDT) tiludronate remain below a value demonstrated in vitro to be safe for articular cartilage (<19,000 ng/ml), and to determine effects of tiludronate on synovial fluid cytology variables compared to saline perfused control limbs. Using a randomized controlled experimental study design, horses received IVRLP with LDT (n = 6) or HDT (n = 6) in one forelimb and IVRLP with saline in the contralateral limb. Synovial fluid cytology variables and tiludronate concentrations were evaluated in navicular bursae (NB), and distal interphalangeal (DIP) and metacarpophalangeal (MCP) joints one week before and 30-45 min after IVRLP, and in DIP and MCP joints 24 h after IVRLP. Data were analyzed with 2-way rmANOVA (p < 0.05). Highest measured synovial fluid tiludronate concentrations occurred 30-45 min post-perfusion. Mean tiludronate concentrations were lower in LDT limbs (MCP = 39.6 ± 14.3 ng/ml, DIP = 118.1 ± 66.6 ng/ml, NB = 82.1 ± 30.2 ng/ml) than in HDT limbs (MCP = 3,745.1 ± 1,536.6 ng/ml, DIP = 16,274.0 ± 5,460.2 ng/ml, NB = 6,049.3 ± 1,931.7 ng/ml). Tiludronate concentration was >19,000 ng/ml in DIP joints of two HDT limbs. Tiludronate was measurable only in synovial fluid from HDT limbs 24 h post-perfusion. There were no differences in synovial fluid cytology variables between control and treated limbs. Conclusions. In some horses, IVRLP with HDT may result in synovial fluid concentrations of tiludronate that may have adverse effects on articular cartilage, based on in vitro data. IVRLP with LDT is unlikely to promote articular cartilage degradation. Further studies to determine a safe and effective dose for IVRLP with tiludronate are needed.

Septic flexor tendonitis and suspensory desmitis in an alpaca.

CASE DESCRIPTION: A 2-year-old male Suri alpaca was referred for evaluation of severe right forelimb lameness of 2 weeks' duration following a traumatic episode. CLINICAL FINDINGS: Examination of the distal aspect of the metacarpus revealed 4 wounds exuding purulent material. On weight bearing, the metacarpophalangeal joint was severely hyperextended with the palmar surface touching the ground. Ultrasonography of the palmar surface of the metacarpus revealed desmitis of the proximal suspensory ligament, a large core lesion of the deep digital flexor tendon at mid-metacarpus, and complete loss of fiber pattern within the deep digital flexor tendon and lateral aspect of the superficial digital flexor tendon distally. TREATMENT AND OUTCOME: The alpaca was treated systemically with antimicrobials and anti-inflammatory drugs and underwent repeated antimicrobial intraosseous regional limb perfusion. A bandage and splint were applied to stabilize the affected forelimb in an anatomically correct position, and the alpaca underwent prolonged stall confinement. At the time of hospital discharge 5 days after initial evaluation, clinical evidence of infection at the wound sites was absent. Three months following treatment, the alpaca was moving freely in a small paddock and had moderate hyperextension of the metacarpophalangeal joint. CLINICAL RELEVANCE: Treatment of septic flexor tendonitis and suspensory desmitis with antimicrobial intraosseous regional limb perfusion in combination with systemic treatment with antimicrobials and orthopedic support resulted in an excellent outcome in this alpaca. Antimicrobial intraosseous regional limb perfusion is simple to perform and has the potential to be beneficial in the treatment of infections in the distal portion of a limb in camelids.

Laparoscopic-assisted urinary bladder marsupialization in a goat that developed recurrent urethral obstruction following perineal urethrostomy.

CASE DESCRIPTION: A 5-year-old castrated male Nigerian Dwarf goat with recurrent urethral obstruction after perineal urethrostomy. CLINICAL FINDINGS: The wether goat was referred for evaluation of a perineal urethrostomy site; perineal urethrostomy had been performed 1.5 years earlier. The site was patent, but a moderate stricture was found just cranial to the perineal urethrostomy site. The goat had obstructed urine flow at the stricture site repeatedly in the previous few months. TREATMENT AND OUTCOME: Laparoscopically assisted urinary bladder marsupialization was recommended. The procedure was performed with the patient under general anesthesia in dorsal recumbency; food had been withheld for 36 hours prior to anesthesia. Ventral midline and left caudal paramedian portals were made for the laparoscopic camera and instruments. A larger incision in the right caudal paramedian portion of the abdomen was used to create the marsupialization stoma. Laparoscopic observation of anatomic structures within the abdomen was excellent. The goat recovered well from surgery and was discharged the day following surgery. Follow-up examinations were done every few months after surgery, and dermatitis of the abdominal skin secondary to urine scald was the only postoperative complication. At 9 months of follow-up, the goat continued to pass urine through the marsupialization site comfortably. CLINICAL RELEVANCE: In the goat of this report, laparoscopic urinary bladder marsupialization was a minimally invasive procedure with minimal signs of postoperative pain. The procedure was simple to perform and should be considered as an alternative to marsupialization via laparotomy.