Suspensory ligament size does not change after plantar fasciotomy and neurectomy of the deep branch of the lateral plantar nerve by ultrasonographic assessment.

OBJECTIVE: To determine the short-term effect of plantar fasciotomy and neurectomy (PFN) of the deep branch of the lateral plantar nerve on the proximal suspensory ligament (PSL) cross-sectional area (CSA) in horses with hindlimb proximal suspensory desmopathy (PSD). STUDY DESIGN: Analytical, observational, cohort study. SAMPLE POPULATION: Twenty-one horses. METHODS: Records of horses with chronic PSD treated by PFN were included if a preoperative ultrasonographic examination was available and at least one postoperative ultrasonographic examination. One masked observer measured the ultrasonographic cross-sectional area (CSA) of the PSL. Intraobserver reliability was determined by repeatedly measuring a subset of ultrasonographic images (n = 127). Two masked observers measured the cross-sectional area of the proximal suspensory ligament (PSL-CSA) on preoperative proton density (PD)-weighted transverse high field magnetic resonance images (n = 19 horses) . Agreements for PSL-CSA between preoperative ultrasonographic and MRI measures and between the two magnetic resonance imaging (MRI) observers were assessed. Follow up considered the horses' ability to return to exercise and their owners' satisfaction. RESULTS: The reliability of the ultrasonographic measurement of the PSL-CSA was excellent. Agreement between ultrasonographic assessment and MRI assessment of PSL-CSA was good. No difference was detected between preoperative (median, interquartile range; oblique-incidence, 2.07, 1.72-2.55; on-incidence, 2.23, 1.98-2.65) and postoperative (oblique-incidence, 2.08, 1.80-2.74; on-incidence, 2.28, 2.01-2.74) PSL-CSAs. At a median of 12 months (4-33 months), 16/20 (80%) owners reported the horse was "better" and 15/20 (75%) functioned at or above preoperative levels. CONCLUSION: Ultrasonographic measurement of the PSL-CSA was reproducible and in good agreement with MRI measurement. The PSL-CSA was not influenced by PFN. CLINICAL SIGNIFICANCE: The PSL-CSA cannot be used to guide return to function.

Compartment syndrome of the muscles of mastication in a working dog following a traumatic training incident.

OBJECTIVE: To describe acute compartment syndrome (CS) of the muscles of mastication in a working dog associated with a traumatic training event. CASE SUMMARY: A 2.5-year-old male Belgian Malinois was evaluated for acute blindness, severe diffuse swelling of the head, and inability to close the jaw following a traumatic incident during a bite training drill. During the exercise, the maxillary canine teeth were locked on a bite sleeve. Magnetic resonance imaging of the head and ocular system identified diffuse muscle swelling and hyperintensity, most severe in the muscles of mastication. Ocular abnormalities were not identified. Rhabdomyolysis, CS, and indirect optic nerve injury were supported by measurement of increased intramuscular pressure. Bilateral decompressive fasciotomies over the masseter and temporalis muscles resulted in immediate and marked resolution of the swelling and jaw movement. Blindness, however, did not resolve. NEW OR UNIQUE INFORMATION PROVIDED: CS involving the muscles of mastication may occur as a complication of bite training and may result in irreversible and even life-threatening complications. Emergent decompressive fasciotomy is indicated to reverse swelling; however, visual deficits may not resolve.

Comparison of Metzenbaum scissors and Y-shaped fasciotome for deep metatarsal fasciotomy for the treatment of proximal suspensory ligament desmopathy in horses.

OBJECTIVE: To quantitate the iatrogenic injury associated with deep plantar metatarsal fasciotomy performed with Metzenbaum scissors compared with a Y-shaped fasciotome. STUDY DESIGN: Experimental ex vivo surgical study. STUDY POPULATION: Cadaveric hind limbs (n = 20) from 10 sound thoroughbred racehorses. METHODS: A plantar metatarsal fasciotomy was performed, extending from the proximal extent of the deep metatarsal fascia, distally. Hind limbs were randomly assigned to 2 groups, undergoing fasciotomy with straight Metzenbaum scissors (n = 10) or a Y-shaped fasciotome (n = 10). Magnetic resonance imaging was performed before and after surgery to identify the maximal depth of any iatrogenic trauma. Gross examination of the surgical site included measuring the length of the incision in the deep metatarsal fascia and localizing iatrogenic trauma sustained by the plantar aspect of the proximal suspensory ligament (PSL) during the procedure. RESULTS: Iatrogenic injury to the PSL was identified in 6 of 10 and 9 of 10 specimens prepared with the fasciotome and Metzenbaum scissors, respectively (P = .03), and was most commonly located in the distal third of the fascial incision. Differences between the length of incision (P = .02) and the maximal depth of signal (P = .03) for incisions created with Metzenbaum scissors or a fasciotome were identified. CONCLUSION: The use of a fasciotome resulted in longer fascial incisions and less severe iatrogenic trauma to the PSL compared with using Metzenbaum scissors. CLINICAL SIGNIFICANCE: A Y-shaped fasciotome may be the preferred surgical instrument for successful desmopathy of the PSL fasciotomy because a greater release of compartmental pressure is possible through a longer incision with minimal iatrogenic trauma to the underlying PSL.

The Effect of Specimen Preparation on Post-Excision and Post-Fixation Dimensions, Translation, and Distortion of Canine Cadaver Skin-Muscle-Fascia Specimens.

OBJECTIVE: To assess the effect of various tissue apposition techniques on specimens after formalin fixation, and to assess canine cadaveric composite skin-muscle-fascia specimen changes after excision without and with addition of a tumor model. STUDY DESIGN: Canine cadaveric study; unbalanced paired design. ANIMALS: Fresh canine cadavers (n = 30) METHODS: Experiment 1: Paired 7 cm diameter, circular skin-muscle-fascia specimens were harvested bilaterally from three sites (thorax, abdomen, and thigh) on 10 cadavers. For each pair, the skin-to-fascia was sutured with a circumferential continuous pattern in one specimen and left unsutured in the other during excision. Specimen length and width were measured post-excision and post-fixation. Specimen rotation, translation, and distortion was measured post-fixation. Experiment 2: A subcutaneous tumor model was implanted at 2 sites (neck, thorax) on 20 cadavers and specimens were then excised with 2 cm lateral margins and a deep fascial plane. Three suturing techniques of the skin-to-fascia at both sites were performed during excision: unsutured versus circumferential continuous suture (10 pairs) or circumferential versus 4 interrupted quadrant sutures (10 pairs). Lateral margins were compared post-excision and post-fixation. RESULTS: Experiment 1: There was significant reduction in the length and width of the fascia and skin post-excision, but no further reduction after fixation. The circumferential suture decreased rotation and translation of the tissue layers but did not significantly affect specimen shrinkage or distortion compared with the unsutured specimen. Experiment 2: All 4 lateral margins decreased significantly post-excision and post-fixation compared with the planned pre-excision margins. No difference was found between any of the 4 lateral margins for any skin-to-fascia suture technique. CONCLUSION: Canine skin-muscle-fascia specimens significantly decrease in size from gross pre-excision dimensions after removal. Suturing the specimen during surgery before excision will significantly improve alignment of tissue planes without creating distortion of the sample, but may alter the length, width, and lateral margins of the specimen.