Effects of regional limb perfusion technique on concentrations of antibiotic achieved at the target site: A meta-analysis.

Intravenous regional limb perfusions (RLP) are widely used in equine medicine to treat distal limb infections, including synovial sepsis. RLPs are generally deemed successful if the peak antibiotic concentration (Cmax) in the sampled synovial structure is at least 8-10 times the minimum inhibitory concentration (MIC) for the bacteria of interest. Despite extensive experimentation and widespread clinical use, the optimal technique for performing a successful perfusion remains unclear. The objective of this meta-analysis was to examine the effect of technique on synovial concentrations of antibiotic and to assess under which conditions Cmax:MIC ≥ 10. A literature search including the terms "horse", "equine", and "regional limb perfusion" between 1990 and 2021 was performed. Cmax (µg/ml) and measures of dispersion were extracted from studies and Cmax:MIC was calculated for sensitive and resistant bacteria. Variables included in the analysis included synovial structure sampled, antibiotic dose, tourniquet location, tourniquet duration, general anesthesia versus standing sedation, perfusate volume, tourniquet type, and the concurrent use of local analgesia. Mixed effects meta-regression was performed, and variables significantly associated with the outcome on univariable analysis were added to a multivariable meta-regression model in a step-wise manner. Sensitivity analyses were performed to assess the robustness of our findings. Thirty-six studies with 123 arms (permutations of dose, route, location and timing) were included. Cmax:MIC ranged from 1 to 348 for sensitive bacteria and 0.25 to 87 for resistant bacteria, with mean (SD) time to peak concentration (Tmax) of 29.0 (8.8) minutes. Meta-analyses generated summary values (θ) of 42.8 x MIC and 10.7 x MIC for susceptible and resistant bacteria, respectively, though because of high heterogeneity among studies (I2 = 98.8), these summary variables were not considered reliable. Meta-regression showed that the only variables for which there were statistically significant differences in outcome were the type of tourniquet and the concurrent use of local analgesia: perfusions performed with a wide rubber tourniquet and perfusions performed with the addition of local analgesia achieved significantly greater concentrations of antibiotic. The majority of arms achieved Cmax:MIC ≥ 10 for sensitive bacteria but not resistant bacteria. Our results suggest that wide rubber tourniquets and concurrent local analgesia should be strongly considered for use in RLP and that adequate therapeutic concentrations (Cmax:MIC ≥ 10) are often achieved across a variety of techniques for susceptible but not resistant pathogens.

Arthroscopic debridement of short frontal plane proximal phalanx fractures preserves racing performance.

BACKGROUND: Outcomes have been reported for a limited number of short frontal plane fractures of the proximal phalanx following nonsurgical treatment and internal fixation. OBJECTIVES: To describe a new approach, arthroscopic debridement, of short frontal plane fractures of the proximal phalanx in flat-racing Thoroughbreds and post-operative racing outcome. STUDY DESIGN: Retrospective case-control study. METHODS: Medical records of 81 Thoroughbred racehorses treated with arthroscopic debridement for frontal plane fractures of the proximal phalanx were reviewed. Diagnostic images and operative reports were used to characterise lesions and a technique for arthroscopic treatment was described. Post injury racing career length, starts, earnings and race quality are compared with matched controls. RESULTS: Of 81 treated horses, 74 (91%) raced post-operatively. Treated horses had fewer post-operative starts compared with controls (median 12, 95% CI 9-16 vs median 19, 95% CI 15-23; P < .001), but there was no difference in post-operative earnings (median $51 465, 95% CI $39 868-$85 423 vs median $68 017, 95% CI $54 247-$87 870, P = .7) or career length (median 7 quarters, 95% CI 5-8 vs median 9 quarters, 95% CI 8-10, P = .1). MAIN LIMITATIONS: Retrospective studies prevent prospective control of sampling bias and limit selection of matched controls. CONCLUSIONS: Treatment of frontal plane fractures of the proximal phalanx by arthroscopic debridement results in racing performance comparable to uninjured controls with respect to longevity and earnings.

Geographic Disparities in Clinical Characteristics of Duodenitis-Proximal Jejunitis in Horses in the United States.

Duodenitis-proximal jejunitis (DPJ) is an idiopathic and potentially fatal disease of horses characterized by abdominal pain, proximal intestinal inflammation, and subsequent gastric and small intestinal fluid accumulation. Although this disease is known to be costly and life threatening in the equine industry, the severity of clinical signs can vary widely, and an exact etiology has yet to be elucidated. This study looked to identify differences in clinical parameters of horses with DPJ between geographic regions in an effort to corroborate anecdotal reports and support theories of differing etiologies. Case records were compared from veterinary academic referral hospitals in three different geographic locations in the United States to determine if significant differences in clinical, clinicopathologic, and prognostic characteristics exist among horses with DPJ. Clinical measurements on presentation that were significantly different between regions included heart rate, peritoneal total protein, albumin, anion gap, aspartate aminotransferase, gamma-glutamyl transferase, sodium, chloride, potassium, and creatinine. Duration of hospitalization and maximum body temperature while hospitalized were also different between regions. There were no significant differences in peritoneal cell count, total white blood cell count, neutrophil count, band neutrophils, calcium, total plasma protein, temperature on presentation, duration of reflux, total reflux volume, or age between hospitals. The mortality rates between hospitals were not significantly different. Increased severity of clinical signs and biochemical abnormalities were identified in the Southeastern United States hospital compared with the Northeastern and Western hospitals. A prospective, multicenter case-control study could identify risk factors contributing toward regional differences in this disease in the future.

Standing Arthroscopic Treatment of Temporomandibular Joint Sepsis in a Horse.

A 15-year-old Thoroughbred gelding was presented for investigation of fever, right temporomandibular region swelling, and progressive pain when opening the mouth. Right temporomandibular joint (TMJ) sepsis was diagnosed based on synovial fluid analysis, sonographic imaging, and standing robotic cone-beam computed tomography. Concurrent otitis media and temporohyoid osteoarthropathy (THO) were also noted. The horse was treated with arthroscopic debridement and lavage during standing sedation followed by local and systemic antimicrobial therapy. There were no complications associated with the surgical procedure and the gelding's clinical signs resolved. Arthroscopy of the TMJ can be accomplished in the standing horse and should be considered when arthroscopic exploration or debridement of this joint is indicated. This is also the first case report of concurrent otitis media, TMJ sepsis, and THO; due to their close anatomic relationship, it is possible that septic otitis media could lead to pathology in the TMJ and temporohyoid joint, as described in humans.