Presence and size of synovial masses within the navicular bursa correlate well between magnetic resonance imaging and bursoscopy and have a guarded prognosis.

BACKGROUND: Focal hyperintense lesions within the navicular bursa emanating from the dorsal border of the deep digital flexor tendon (DDFT) can be recognised on T1-weighted magnetic resonance images (MRI) and have been attributed to lameness in horses. Removal of these lesions, also referred to as synovial masses, by navicular bursoscopy is currently recommended. OBJECTIVES: To investigate the correlation between MRI and navicular bursoscopic findings. It is hypothesised that the prognosis following surgery is proportional to the size of the DDFT lesion. STUDY DESIGN: Retrospective analysis of clinical records. METHODS: Horses undergoing standing low-field MRI and navicular bursoscopy with >1 year follow-up were included. A grading system was developed to classify the size of synovial mass(es) and lesion(s) of the DDFT on MRI and at surgery. Generalised estimating equations were used to evaluate the association between MRI findings and surgery and between outcome and severity of the tendon injury. RESULTS: Fifty-nine horses presenting over a 15-year period (2006-2021) fulfilled inclusion criteria. Ninety navicular bursae were examined both on MRI and endoscopically. There was strong correlation between the size of synovial masses and tendon lesions on MRI and bursoscopy (p < 0.001, OR: 25.61, 95% CI 8.71-75.29 and p < 0.001, OR: 7.34, 95% CI 2.70-19.92, respectively). Size of tendon lesion and synovial mass had no impact on prognosis (p = 0.3, OR: 1, 95% CI 1-1 and p = 0.1, OR: 1, 95% CI 1-1, respectively), which was guarded (30.5% return to previous level of exercise). MAIN LIMITATIONS: Performance data for conservatively treated horses with MRI-detected synovial masses was not considered, nor was the effect of navicular bursal effusion. Horses were not randomly assigned to treatment protocols. CONCLUSION: There is good correlation between MRI and bursoscopic findings of DDFT lesions and synovial masses within the navicular bursa, with no false positives. Size of the synovial masses and DDFT lesions does not influence prognosis following navicular bursoscopy.

A multi-centre cohort study investigating the outcome of synovial contamination or sepsis of the calcaneal bursae in horses treated by endoscopic lavage and debridement.

BACKGROUND: Previous studies investigating factors associated with survival following endoscopic treatment of contamination/sepsis of the calcaneal bursa are limited. OBJECTIVES: To investigate the factors associated with survival in horses with contamination/sepsis of the calcaneal bursae treated endoscopically and to describe the bacterial isolates involved in the synovial infections. STUDY DESIGN: Retrospective analysis of clinical records. METHODS: Medical records from 128 horses with contamination/sepsis of the calcaneal bursae treated by endoscopic lavage at seven equine hospitals were reviewed. A follow-up questionnaire was used to determine survival and return to athletic performance. Descriptive statistics and Cox proportional hazards survival models were used to determine factors associated with survival. RESULTS: Horses underwent one (n = 107), two (n = 19), or three (n = 2) surgeries. Survival to hospital discharge was 84.4%. Univariable survival analysis revealed that administration of systemic antimicrobials prior to referral was associated with reduced mortality (hazard ratio, [HR] 0.41, 95% CI 0.18-0.91, P = 0.03). Increased mortality was associated with bone fracture/osteomyelitis (HR 2.43, 95% CI 1.12-5.26, P = 0.03), tendon involvement (≥30% cross sectional area) (HR 3.78 95% CI 1.78-8.04, P = 0.001), duration of general anaesthesia (HR 1.01, 95% CI 1.00-1.02, P = 0.04), post-operative synoviocentesis (HR 3.18, 95% CI 1.36-7.43, P = 0.006) and post-operative wound dehiscence (HR 2.5, 95% CI 1.08-5.65, P = 0.04). Multivariable Cox proportional hazards model revealed reduced mortality after systemic antimicrobial administration prior to referral (HR 0.25, 95% CI 0.11-0.60, P = 0.002) and increased mortality with tendinous involvement (≥30% cross-sectional area) (HR 7.92, 95% CI 3.31-19.92, P<0.001). At follow-up (median 30 months, range 0.25-13 years, n = 70) 87.1% horses were alive, 7.1% had been euthanised due to the calcaneal injury and 5.7% had been euthanised for unrelated reasons. From 57 horses with athletic performance follow-up, 91.2% returned to the same/higher level of exercise, 5.3% to a lower level and 3.5% were retired due to persistent lameness of the affected limb. MAIN LIMITATIONS: Retrospective study and incomplete follow-up. CONCLUSION: Endoscopic treatment of contamination/sepsis of the calcaneal bursae has an 84% survival rate to hospital discharge. Tendinous involvement reduced survival whilst systemic antimicrobials administration prior to referral improved survival.

Diagnosis, treatment and outcome of cranial nuchal bursitis in 30 horses.

BACKGROUND: No large retrospective case series describing the treatment and outcomes following diagnosis of cranial nuchal bursitis have been published. OBJECTIVE: To describe the clinical presentation, diagnostic techniques, treatment and outcome of horses suffering from cranial nuchal bursitis and to determine their outcome after medical or surgical treatment. STUDY DESIGN: Retrospective case series. METHODS: Medical records (1990-2014) of two referral centres were reviewed for signalment, diagnostic features, method of treatment (medical, surgical or both) and outcome. RESULTS: The median age of horses was 13 years (range 5-22 years) and follow-up time ranged from 12 to 108 months. Fourteen horses were treated medically and 20 horses were treated surgically. Of those horses treated medically, four horses had recurrence of clinical signs requiring subsequent surgical treatment. Overall, 41.7% of horses had recurrence of clinical signs following treatment and 66.7% of horses were able to return to their previous level of exercise. Five horses underwent more than one surgical procedure due to recurrence of clinical signs. Of those horses treated solely surgically, 28.6% of the horses had recurrence of clinical signs and 78.6% returned to their previous level of exercise. Of those horses treated solely medically, 33.3% had recurrence of clinical signs and 66.7% returned to their previous level of exercise. Of those horses treated surgically following failed medical management, 100% had recurrence of clinical signs and 25% returned to their previous level of exercise. MAIN LIMITATIONS: Retrospective design with small sample number. CONCLUSIONS: Nuchal bursitis can be successfully managed with either medical or surgical treatment. Prognosis for return to work tends to be worse in horses requiring surgical intervention following failed medical management.

The cranial nuchal bursa: anatomy, ultrasonography, magnetic resonance imaging and endoscopic approach.

REASONS FOR PERFORMING STUDY: Although an uncommon condition, cranial nuchal bursitis can affect the performance of the equine athlete. The anatomy is not well described and there are no reports of diagnostic imaging for endoscopic approaches. OBJECTIVES: To describe the anatomy, ultrasonographic and magnetic resonance features of and endoscopic approach to the cranial nuchal bursa in horses. STUDY DESIGN: Experimental cadaver study. METHODS: Four cranial nuchal bursae were dissected, 4 specimens were frozen to prepare anatomical sections and 2 were injected with latex to document surface landmarks and topographical anatomy and to identify the possible sites for endoscopic access. Six cadaveric specimens were used to describe the ultrasonographic and magnetic resonance features of the cranial nuchal bursa before and after intrabursal injection. Sixteen cadaver specimens were evaluated with a rigid arthroscope and gross dissection to determine the endoscopic appearance of the bursa. RESULTS: The cranial nuchal bursa could be identified consistently in all cadavers, using ultrasonographic and magnetic resonance on both pre- and post injection specimens. Cranial and caudal endoscopic approaches and instrument portals were developed for the cranial nuchal bursa. Using either approach, the entire extent of the bursa could be evaluated, but separate approaches for left and right compartments of the bursa were needed owing to the lack of manoeuvrability when examining the contralateral compartment. CONCLUSIONS: The cranial nuchal bursa can be identified on ultrasonographic and magnetic resonance images. An endoscopic approach to the cranial nuchal bursa is clinically feasible and offered an easy, repeatable entry into the cranial nuchal bursa, which allowed adequate observation of the structures within the bursa. This may be of help for diagnosis and treatment of conditions affecting the cranial nuchal bursa in horses.