Outcome of tenoscopically guided palmar/plantar annular ligament desmotomy for the treatment of palmar/plantar annular ligament constriction without concurrent intrathecal soft-tissue injury in a UK horse population.

OBJECTIVE: To determine the outcome of tenoscopically guided palmar/plantar annular ligament (PAL) desmotomy to treat PAL constriction without concurrent intrathecal soft-tissue injury, notably of the digital flexor tendons and manica flexoria. STUDY DESIGN: Retrospective multicenter cohort study. ANIMALS: Sixty-five horses. METHODS: Horses from four UK equine hospitals, with digital flexor tendon sheath (DFTS) tenosynovitis, which underwent tenoscopically guided PAL desmotomy for treatment of PAL constriction between 2017 and 2022 were included. All horses had lameness isolated to the DFTS/PAL, and PAL constriction was diagnosed tenoscopically when there was difficulty maneuvering the endoscope into or through the fetlock canal. Horses with tearing of the digital flexor tendons and/or manica flexoria, or any other intrathecal pathology, were excluded. Follow up was via structured telephone questionnaire. RESULTS: Follow up (median 25 months) was available for 61 horses with cobs and ponies predominating. Forty-two returned to their previous level of work, or a higher level, postoperatively and 50 owners were satisfied with the outcome of surgery. Eleven horses returned to lower level exercise, and six were retired/euthanized as they did not regain soundness. Fifty-two horses achieved soundness (median 3 months postoperatively). CONCLUSION: Tenoscopically guided PAL desmotomy for the treatment of PAL constriction in the absence of intrathecal soft tissue injury had a good prognosis for return to previous levels of exercise in a UK horse population. CLINICAL SIGNIFICANCE: The prognosis for horses undergoing tenoscopically guided PAL desmotomy to treat PAL constriction in the absence of intrathecal injury is better than previously described. Cobs and ponies seem to be predisposed to PAL constriction in agreement with the previous literature.

Ultrasonographic guidance for perineural injections of the cervical spinal nerves in horses.

OBJECTIVE: To evaluate the accuracy of ultrasonographic guidance for injection near the ventral rami of the cervical spinal nerves (VRCSN). STUDY DESIGN: Ex vivo study. SAMPLE POPULATION: Ten cadavers (n = 40 injections). METHODS: Left and right VRCSN at C4/5 and C5/6 were infiltrated at the intervertebral foramen (IVF) under ultrasonographic guidance. A vertically orientated 3.5-MHz curvilinear probe was used to identify the craniocaudal midpoint of the articular process joint (APJ). The probe was moved ventrally until the IVF was identified. An 18-gauge 15-cm-long spinal needle was aimed immediately below the ventral margin of the cranial articular process, where 1 mL of latex was injected. Cadavers were dissected, and the location of the latex was recorded relative to the ventral ramus, the spinal cord, and the vertebral artery. RESULTS: Direct infiltration of the ventral ramus occurred in 73% (29/40) of injections; 15% (6/40) of injections were < 0.5 cm from the ventral ramus, and 13% (5/40) of injections were > 0.5 cm (maximum 1.5 cm). Latex was located at a mean of 2.4 cm (range, 0.8-4) from the spinal cord and 0.9 cm (range, 0-1.5) from the vertebral artery. CONCLUSION: Ultrasonographic guidance of perineural injections of the caudal VRCSN was repeatable and accurate, with 88% of injections located within 0.5 cm of the ventral ramus. Iatrogenic damage was limited to one penetration into the vertebral artery. CLINICAL SIGNIFICANCE: Ultrasonographic guidance of perineural injections of the caudal VRCSN may be considered by operators experienced in cervical APJ scanning in horses with suspected cervical spinal nerve compression.