Sensory nerve conduction and nociception in the equine lower forelimb during perineural bupivacaine infusion along the palmar nerves (original) (raw)
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Acta Scientiae Veterinariae
Background: Local anesthesia blockage at equines claudication diagnosis besides favoring the beginning of the therapy and relieving patient’s pain, it allows the identification of the specific affected region and its origin, however, if it is done incorrectly (by improper volume of anesthetics application and/or mistakenly nerve identification due to the lack of anatomic referential) it may cause inflammation, infection or even tissue necrosis. The aim was describing anatomically lateral and medial palmar metacarpal nerves in equines to improve diagnostic anesthetic block techniques on four metacarpophalangeal articulation joints of the specie.Materials, Methods & Results: A number of 20 thoracic limbs from 10 equines of indeterminate breed were used to be fixated in 10% phormaldehyde and with a marked arterial system by water solution of red dyed latex. The structures were identified by dissection, and their denomination bases on Nomina Anatomica Veterinaria (N.A.V.) by the Interna...
Continous Nerve Block of the Thoracic Limb in Horses
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Veterinary Medicine, 2012
Analgesia is of great importance in surgical trauma occurring in horses. In the present, long term epidural analgesia has become a routine method for trauma of the hind limb, but, in the case of the thoracic limb there is no regular similar technique. Continuous nerve block is a method using a local continuous perfusion with anesthetics administered through a catheter placed along the direction of peripheral nerves and it represents a new analgesia technique. This method is frequently used in human medicine to reduce post-surgical pain in body extremities. Continuous nerve block doesn't affect the general state of health of equines, and through the induction of analgesia it encourages healing conditions. The present study aims to develop a treatment method usable on tranquilized standing horses, by placing a catheter along the palmar nerves of the thoracic limb. We have studied the main anatomical points for placing the catheter along the peripheral nerves of the thoracic limb a...
Development of a peripheral nerve stimulator-guided technique for equine pudendal nerve blockade
The Veterinary Journal, 2016
The aim of this study was to develop and evaluate a procedure for equine pudendal nerve block using a peripheral nerve locator. In the first experiment, six ponies were used to determine the relationship between elicited muscle contractions (anal, perineal or both) and nerves serving the perineal region (pudendal, caudorectal and perineal nerves) when methylene blue dye was injected using the electrolocation technique. This experiment showed that the pudendal nerve was approached effectively when both anal and perineal twitch were elicited during electrolocation. In a second experiment, seven Thoroughbred horses were used to evaluate the appropriate volume of anaesthetic solution for the nerve block. Immediately after euthanasia, lidocaine/methylene blue solution was injected after positive electrolocation. A stained segment of 2 cm or more of the nerve was considered effective and this was evaluated after dissection. Both 10 and 20 mL per injection site resulted in effective nerve staining. Finally, pudendal nerve block was performed and evaluated in 27 horses admitted for selected reproductive surgical procedures including perineoplasty, urethroplasty, clitorectomy in mares and penile examination, phallectomy and urethrostomy in geldings. Surgical time varied from several minutes to 3 h. The choice between lidocaine, mepivacaine or bupivacaine was based on the duration of analgesia required. In mares and males, a volume of 20 mL and 10 mL, respectively, was injected per site. The use of a peripheral nerve stimulator-guided pudendal nerve block is a feasible, safe and reliable alternative for both epidural and general anaesthesia, to provide peri-operative analgesia in clinical equine patients undergoing specific reproductive surgeries.
Mepivacaine local anaesthetic duration in equine palmar digital nerve blocks
Equine Veterinary Journal, 2010
Reasons for performing study: Perineural analgesics are used for lameness diagnosis but the duration of effect, knowledge of which would provide valuable information when performing subsequent blocks, is unknown. Objective: To evaluate the duration of a palmar digital nerve block using force plate measurements. Methods: Ten horses diagnosed with unilateral navicular syndrome were trotted at range of 3 ± 0.15 m/sec over a force plate to record ground reaction forces for 5 trials of each forelimb. Data were recorded before nerve block, and then at 15 mins, 1, 2 and 24 h post nerve block. Results: Before nerve block, peak vertical force (mean ± s.e.) was significantly higher in the contralateral forelimb (CL = 5345 ± 188 N) than in the lame forelimb (L = 4256 ± 204 N; P<0.05). At 15 mins post nerve block there was no significant difference between the 2 forelimbs (CL = 5140 ± 184 N; L = 5126 ± 129 N), and this remained the case for 1 h. By 2 h, the mean score for the lame leg had decreased (L = 4642 ± 182 N) but was still greater than preblock. By 24 h, vertical forces had returned to preblock values. Conclusions: The palmar digital nerve block was fully effective between 15 mins and 1 h. The analgesic effect began to subside between 1 and 2 h but sufficient analgesia persisted to affect gait characteristics beyond 2 h. Potential relevance: When using a palmar digital nerve block, it is important to perform lameness evaluations between 15 mins and 1 h to be sure of effective nerve blockade.
American Journal of Veterinary Research, 2014
Objective—To determine analgesic effects of intraneural injection of ethyl alcohol or formaldehyde in the palmar digital nerves of horses. Animals—6 horses. Procedures—Ethyl alcohol was injected in the medial palmar digital nerve of 1 forelimb, and formaldehyde was injected in the contralateral nerve. The lateral palmar digital nerve in 1 forelimb was surgically exposed, but not injected, and the contralateral lateral palmar digital nerve was not treated. For each heel, severity of lameness in response to experimentally induced heel pain (lameness score and peak vertical force), thermal reaction time, and heel skin sensitivity scores were recorded. Heel pain was experimentally induced by advancing a threaded bolt through a custom-made horseshoe to apply pressure to the palmar horned aspect of the hoof. Horses were followed up for 112 days, when a subset of nerves was sampled for histologic analysis. Results—Alcohol and formaldehyde significantly reduced all measures of heel pain, an...
American Journal of Veterinary Research, 2020
OBJECTIVE To evaluate the analgesic and tissue effects of liposomal bupivacaine administered SC as an abaxial sesamoid nerve block in horses with experimentally induced lameness. ANIMALS 6 healthy mature light-breed horses. PROCEDURES In a randomized crossover study, a circumferential hoof clamp was applied to a forelimb to induce reversible lameness. An abaxial sesamoid nerve block of the lame forelimb was performed by SC perineural injection of 10 mg of liposomal bupivacaine or bupivacaine HCl/site. Quantitative gait data were objectively obtained with a body-mounted inertial sensor system before (baseline) and at 30-minute intervals after treatment. Time to return to 85% of baseline lameness was determined. After a minimum 4-day washout period, procedures were repeated with the alternate limb and treatment. Lastly, the palmar digital nerves and perineural tissues were collected and examined histologically. RESULTS SC perineural injection of liposomal bupivacaine ameliorated forel...
PLOS ONE
The analgesic specificity of navicular bursa (NB) anesthetic infiltration is still questionable. The study aimed to determine the mechanical nociceptive threshold of non-specific analgesia in the dorsal lamellar stratum, as well as in the sole, coronary band, and heel bulbs of the hoof, after navicular bursa anesthetic infiltration. Six healthy horses with no clinical or radiographic changes of the digits and no communication between the NB and the distal interphalangeal joint, were used. After random selection, the NB of one of the forelimbs was infiltrated with 2% lidocaine and the contralateral one with lactated ringer’s solution. Contrast was added to confirm radiographic infiltration. The mechanical nociceptive threshold was determined using a portable pressure dynamometer, before and at various times after the infiltration, in 10 points of the hoof. The effects of time and treatment were verified by ANOVA (P<0.05). There was no statistical difference in the values of the me...
Equine Veterinary Journal, 2010
limited on distribution of local anaesthetic solution following perineural analgesia of the palmar (Pa) and palmar metacarpal (PaM) nerves in the distal aspect of the metacarpal (Mc) region ('low 4-point nerve block'). Objectives: To demonstrate the potential distribution of local anaesthetic solution after a low 4-point nerve block using a radiographic contrast model. Methods: A radiodense contrast medium was injected subcutaneously over the medial or the lateral Pa nerve at the junction of the proximal three-quarters and distal quarter of the Mc region (Pa injection) and over the ipsilateral PaM nerve immediately distal to the distal aspect of the second or fourth Mc bones (PaM injection) in both forelimbs of 10 mature horses free from lameness. Radiographs were obtained 0, 10 and 20 min after injection and analysed subjectively and objectively. Methylene blue and a radiodense contrast medium were injected in 20 cadaver limbs using the same techniques. Radiographs were obtained and the limbs dissected. Results: After 31/40 (77.5%) Pa injections, the pattern of the contrast medium suggested distribution in the neurovascular bundle. There was significant proximal diffusion with time, but the main contrast medium patch never progressed proximal to the mid-Mc region. The radiological appearance of 2 limbs suggested that contrast medium was present in the digital flexor tendon sheath (DFTS). After PaM injections, the contrast medium was distributed diffusely around the injection site in the majority of the limbs. In cadaver limbs, after Pa injections, the contrast medium and the dye were distributed in the neurovascular bundle in 8/20 (40%) limbs and in the DFTS in 6/20 (30%) of limbs. After PaM injections, the contrast and dye were distributed diffusely around the injection site in 9/20 (45%) limbs and showed diffuse and tubular distribution in 11/20 (55%) limbs. Conclusions and potential relevance: Proximal diffusion of local anaesthetic solution after a low 4-point nerve block is unlikely to be responsible for decreasing lameness caused by pain in the proximal Mc region. The DFTS may be penetrated inadvertently when performing a low 4-point nerve block.