Choice anaesthesia method for cattle hind limb surgical interventions (comparison

Basically, the administration of local anaesthesia can remove behavioral reactions resulted by pain for period of local anaesthetics’ action. Furthermore, after finishing the duration of local anesthesia activity, the behavioral indicators of pain in calves can be similar to behavioral reactions which appear without local anaesthesia (SYLVESTER et al., 2004). In general, for intravenous regional anaesthesia, the vein of a limb is catheterized.

Afterwards, the limb should be exsanguinated using esmarch bandage, then a tourniquet can be applied around the limb with an adequate pressure to prevent arterial circulation (> 150 mmHg). Thereafter, local anaesthetic which preferably has no epinephrine could be injected into the planned vein. Subsequently, following 15 minutes, the area distal to the applied tourniquet would be desensitized till deflation of the tourniquet (MARONQIU, 2012). In our study evaluating the efficacy as well as onset of two local anesthesia methods, the method for intravenous regional anaesthesia was performed base on regional intravenous anaesthesia method of ANTALOVSKÝ (1965). ANTALOVSKÝ mentioned that according to their clinical and experimental experience, local intravenous anaesthesia would be ‘‘good enough’’¹ to be one of the possibilities of local anaesthesia especially in cattle. According to ANTALOVSKÝ (1965), the most benefits of local intravenous anaesthesia are include of

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‘‘high efficacy’’ as well as ‘‘low consumption of anaesthetic’’, ‘‘the minimum tissue injuries’’

as well as ‘‘the minimum whole body toxicity’’. According to SKARDA (1996), the advantages of intravenous regional anaesthesia compared to ring block or nerve block anaesthesia could be only one required needle for injection which can reduce risk of inducing bacteria infections. AVEMANN (1974), demonstrated that full intravenous regional anaesthesia can occure about 2 - 8 minutes after anaesthesia application with an average duration of 99 minutes. It must be mentioned that AVEMANN (1974), used lidocaine to desensitize bovine limb while in our study, procaine has been used as an anaesthetic. In our study, the delay to have a full intravenous regional anaesthesia (15 minutes) compared to AVEMANN (1974) study could be the different effect of different anaesthetics which have been used for local anaesthesia. It could be assumed that good anaesthesia with a regional method can result in declining the postoperative pulmonary complications. Moreover, regional anaesthesia has an effect in moderating some of cardiovascular responses to operation which come from sympathetic activation. Another statement related to preference of intravenous regional anaesthesia is that, this method could be used as a suitable routine technique for bovine claw surgeries, painful claw therapies as well as claw amputation which is an effective easy method to obtain the completed desensitized area of planned surgery or treatment which could be applied without detailed anatomical knowledge (KÖPPEN, 2014).

According to PRENTICE et al. (1974), the duration of local anaesthesia’s efficacy depends on applied volume of anaesthetic. The considerable benefits of intravenous regional anaesthesia are easiness of its application as well as reliability and performing this technique which only requires the venipuncture skill (BROWN et al., 1989). However, the effectiveness and saftieness of this anesthesia method have been questioned in some studies related to the pressure of tourniquet, systemic toxicity following deflation of tourniquet and so on (LAWES et al., 1984; HEATH, 1982; OGDEN, 1984; LUCE, 1983). Furthermore, application of IVRA method could fail due to tourniquet pain (CHAN et al., 2001). On the other hand, according to BROWN et al. (1989), the main cause of side effects or failure of this anaesthesia technique could be ‘‘technical errors’’. However, in our second study evaluating onset of two anaesthesia methods, the results of nociceptive threshold measurements includes of electrical and mechanical pressure as well as pin pricks nociceptive responses demonstrated that one cow did not show full intravenous regional anaesthesia till end of examination day which according to BROWN et al. (1989), could be due to technical errors or against due to induced tourniquet - pain (CHAN et al., 2001), which needs more investigations with increasing numbers of dairy cows in the study. In human, intravenous regional anaesthesia as a useful

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analgesia method against its occasional reports, has not gained general agreement (BELL et al., 1963; KENNEDY et al., 1965; EDITORIAL JAVMA, 1965). In some studies, it has been clearly highlighted that, intravenous regional analgesia (IVRA) is the ‘‘technique of choice’’

for distal bovine limb operations in order that it has a fast onset and could be easily applied and would be ‘‘more reliable’’ than nerve blocks (HEPPELMANN et al., 2009; AVEMANN, 1974; PRENTICE et al., 1974; FEHLINGS, 1980; POHLMEYER, 1984; STEINER et al., 1990; THURMON and KO, 1997; KLAWUHN and STAUFENBIEL, 2003; RIZK et al., 2012). Against, according to DIRKSEN (2002), the nerves which supply the digit could be simply blocked (DIRKSEN, 2002). On the other hand, according to HALL et al. (2001), in order that, the innervation of bovine digit is more complicated than horse, nerve block regional anaesthesia of bovine foot could be more difficult compared to horse because the skin below the carpus (in forelimb) and tarsus (in hindlimb) is rigid, therefore, finding the exact location of nerves cannot be simple. GIBBONS (1939), has an examination of claw amputation under regional nerve blocks with a cow in standing position which was successful.

However, even though, nerve block local anaesthesia has been described in some review (not practical) articles (RAKER, 1956) as well as some books (HABEL, 1950; WRIGHT, 1946;

WAY, 1954), and even though sites of injections for nerve blocks were suggested (RAKER, 1956; HALL et al., 2001), no clinical (practical) study till now (in our knowledge) has been found to use local nerve blocks even in some numbers of cows to investigate the analgesia’s quality (duration and/or efficacy of full anaesthesia) and/or quantity (onset of full anaesthesia) not only to compare with another foot local anaesthesia method such as intravenous regional anaesthesia but also there is no study to validate local nerve blocks as a foot local anaesthesia technique to desensitize the hind limb in cows. The method to block superficial, deep, common peroneal and tibial nerves in some text books and review articles have been described already (BROCK and HEARD, 1985; COLLIN, 1963; RAKER, 1956; SKARDA, 1986; WESTHUES and FRITSCH, 1964). WESTER and BEIJERS (1928), suggested 3-points nerve block anaesthesia to desensitize the bovine foot. HALL et al. (2001), reported bovine hind limb nerve blocks of fibular and tibial nerves above the hock can be performed to have a local anaesthesia below the hock. To desensitize the fibular nerve, injection can be done with 18 or 20 gauge 2.5 cm needle ‘‘through the skin and through the aponeurotic sheet of biceps femories until the point of the needle just touches the caudal edge of the lateral condyle of the tibia’’. Anaesthesia can be approached after 20 minutes. To desensitize tibial nerve ‘‘grasp the gastrocnemius (Achilles) tendon between the thumb and index finger of one hand about 10 - 12 cm above the summit of calcaneous, insert a 2.5 cm needle just below the

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thumb until the point of the needle can be felt by the index finger, just below the skin on the other side of the tendon. Inject 15 - 20 ml local anaesthetic solution and inject an additional 5 ml on the medial side of the leg to block a small cutaneous nerve at this site’’. Anaesthesia can be achieved after 15 minutes under this method. Elmore (1981), suggested bovine anterior and posterior digital nerve block anaesthesia by injection respectively ‘‘in the soft area just dorsal to the fibrous band joining the claws’’ and ‘‘just dorsal to the fibrous band joining the claws’’.

According to RAKER (1956), and HALL et al. (2001), the bovine hind foot can be desensitized by introducing the anaesthetic at 4 sites of superficial and deep peroneal, medial and lateral plantar metatarsal nerves. He suggested to desensitize superficial peroneal nerve, the nerve can be blocked ‘‘after inserting a ½ inch needle at the junction of the proximal and middle thirds of the metatarsus on its dorsal surface’’. Also, to desensitize deep peroneal nerve, he suggested that ‘‘the nerve is approached from the lateral side using a 1 inch, 22 gauge needle. This longer needle is inserted along its full length from the lateral side and is directed medially, so it passes beneath the extensor tendons and lies on the dorsal surface of the metatarsal bone’’. He continued that to desensitize the lateral plantar metatarsal nerve, ‘‘a

½ - inch needle is inserted between the suspensory ligament and the flexor tendons at the middle of the metatarsus’’ while medial plantar metatarsal nerve can be blocked ‘‘by injecting the anaesthetic agent at the middle of the metatarsus medial to and between the suspensory ligament and flexor tendons’’. CLARKE et al. (2013), in their book suggested desensitizing cattle hind digit with blocking fibular nerve by injection ‘‘through the skin, the subcutaneous tissue and the aponeurotic sheet of the biceps femoris until its point just touches the bony landmark’’, and tibial nerve by injection ‘‘above the summit of the calcaneus on the medial aspect of the limb, just in front of the gastrocnemius tendon’’, and further injection on ‘‘the lateral side of the leg to block a small cutaneous nerves’’. In another text book, bovine hind limb nerve block anaesthesia to have a desensitized metacarpus/metatarsus with blocking tibialis nerve, superficial and deep fibular nerves, 3-points proximal nerve block anaesthesia, 3-points distal nerve block anaesthesia to have a desensitized claw or even 4-points nerve block anaesthesia with blocking four nerves includes of digitalis dorsalis proprius IV axialis, digitalis plantaris proprius IV axialis, digitalis dorsalis proprius IV abaxialis and digitalis plantaris proprius IV abaxialis have been described already (FIEDLER et al., 2003).

GREENOUGH (1997), described 4-points distal digital nerve block anaesthesia in his text book explaining his method is unreliable for digital anaesthesia of thorasic limb in order that nerve distribution of digits of thorasic limb is not constant. According to Collin (1963), the capacity of local anaesthesia method which can induce desensitization by blocking nerves as

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far away as possible from the location of surgery, is an advantage. He highlighted that in bovine hind limb, the main nerve for anaesthesia application can be ‘‘the main nerve trunk, the sciatic’’. In his opinion, blocking this nerve can be simple to perform but it can induce complete limb paralysis which would not be desirable. The benefit of choosing main branches of sciatic nerve includes of peroneal and tibial nerves is that by desensitizing those nerves, the desensitized bovine hind limb will be obtained in the farthest away from the operative area.

Collin (1963), used peroneal nerve block ‘‘immediately behind the posterior edge of the lateral condyle of the tibia’’ and to block tibial nerve ‘‘approximately in front of the achilles tendon’’. By this way, the time to induce desensitization for peroneal nerve is 5 – 20 min while for tibial nerve would be up to 15 min (Collin, 1963). However, in our 4-points nerve block anaesthesia method the injection sites to desensitize superficial and deep peroneal, lateral and medial plantar metatarsal nerves are different compared to those suggested injection sites and bovine right hind limb 4-points nerve block anaesthesia was performed with blocking the superficial peroneal nerve by injection directly beneath the skin subcutaneously on the dorsal surface of hind leg proximally to the hock joint, desensitizing deep peroneal nerve with injection inside the proximal region of the groove at the dorso-medial surface of metatarsus preventing disturbing deep peroneal artery and vein which are inside the groove with deep peroneal nerve, blocking lateral and medial plantar metatarsal nerves with injections respectively perineurally at the lateral surface of mid metatarsus above superficial and deep flexor tendons and at the medial surface of mid metatarsus above the superficial flexor tendon. As about more than ten right and left hind limbs of slaughtered or euthanized dairy cows have been dissected professionally with cooperation of anatomy department to prepare and localize the bovine hind limb innervation, according to our observations, nerves’ localization of right and left hind limbs in dairy cows are different and the injection sites to block four nerves (superficial and deep peroneal, lateral and medial plantar metatarsal nerves) which have been used in our study are suggested to perform only to desensitize bovine right hind limbs. Regarding complications and side effects of intravenous regional anaesthesia application, tourniquet pain beneath and distal to inflated tourniquet resulted in mechanical compression of tourniquet, muscle and nerve ischemia secondary to tourniquet pain, increasing cardio respiratory factors, heart rate, diastolic and systolic blood pressure following tourniquet inflation, hypoxia, hyper-capnea, acidosis, hyper-kalemia, increased lactate concentration and systemic toxicity following tourniquet release, potential hematoma at the injection site, lack of anaesthesia in order to slipping the tourniquet could be mentioned (BOURKE et al., 1989; KAM et al., 2001; PEDOWITZ and GERSHUNI, 1993;

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PARKASH et al., 1988; SKARDA, 1996; EJAZ et al., 2015) as well as this point that foot intravenous regional anaesthesia cannot be easily applicable in some cases such as intens cellulitis (EDMONDSON, 2008; ANDERSON and EDMONDSON, 2013), while neural injury consist of direct mechanical needle trauma to nerves, mechanical trauma due to intraneural injection, local anaesthetic neurotoxicity, ischemia due to pressure effects of perineural or intraneural injections can be highlighted as complications of nerve block anaesthesia (KENT and BOLLAG, 2010). On the other hand, some benefits of performing local nerve block anaesthesia such as reduced opioid requirement, decreased incidence of hemodynamic instability, and less postoperative nausea, vomiting and improve postoperative pain control have been already reported in human (WIEGEL et al., 2007; RICHMAN et al., 2006; CAPDEVILA et al., 2005; EVANS et al., 2005; SINGELYN et al., 2005; BEN-DAVID et al., 2004; CAPDEVILA et al., 1999; SINGELYN et al., 1998). The results of our study demonstrated no significant effect of tourniquet application or deflation on pain, however, significant lower level of mean arterial blood pressure in nerve block anaesthetized cows compared to intravenous regional treated group after returning cows to standing position from lateral recumbency before deflation of tourniquet can be considerable. Regarding 4-points nerve block anaesthesia, injections were performed preneurally (superficial and deep peroneal, lateral and medial plantar metatarsal nerves), therefore the side effect of neural injuries due to direct mechanical needle trauma would be neglected. Additionally, till now, any study method regarding neural blockade are beneficial in cardiac morbidity as well as outcome compared to the other pain killer’s techniques has not been organized (KEHLET, 1999; LUI et al., 1995; DESBOROUGH, 2000). However, according to BAGRY et al. (2008) and MARTIN et al. (2008), clinical peripheral nerve blocks demonstrated that they may decline the postoperative inflammatory responses. CHAN et al. (2013) as well as SAKAI et al. (2013), highlighted that peripheral nerve blocks has some benefits includes of better analgesic control, fewer opioid-associated adverse effects, earlier improvements in knee flexion as well as less pain during rehabilitation. Following peripheral nerve block, an improved postoperative knee flexion and more rapid recovery of functional autonomy will be appeared. Moreover, peripheral nerve blocks have an anti-inflammatory efficacy (MARTIN et al., 2008). Studies in human (PEDERSEN et al., 1996; GORDON et al., 1997;

GOTTSCHALK et al., 1998) and animals (KISSIN et al., 1998), showed that nerve block can have a remarkable effect on both inflammation and nociception. MARTIN et al. (2008), by agreement with that opinion of the effect of peripheral nerve block on postoperative functional recovery reported that peripheral nerve blocks can reduce edema and temperature

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raise in human after surgery. Both single and continuous femoral nerve block can provide pain relief more than intravenous patient controlled analgesia. Within the early post operative period the analgesic efficacy of single injection as well as continuous femoral nerve blocks is superior compared to intravenous patient controlled anaesthesia in the early post-surgical period (CHAN et al., 2013). According to our results, both intravenous regional and 4-points nerve block anaesthesia can induce full anaesthesia at the distal hind limb of dairy cows. As our results have not been presented as an oral presentation in international events and other bovine veterinarians and surgeons most likely do not know about the advantages of this new verified method, and in order that different conditions need different local anaesthesia method, this new verified bovine foot local anaesthesia method can be applied as a choice local anaesthesia method as well as an alternative technique. Veterinarians and surgeons could choose their own routine local anaesthesia method depends on different surgical conditions and so on. The most benefit of application of 4-point NBA to desensitize hind limb of cattle is faster onset of full anaesthesia compared to a simple routine one (IVRA). Another benefit which needs further studies could be better recovery condition with less pain following surgery. However, faster full onset of 4 – point NBA compared to IVRA would be beneficial when surgeries have to be done under time constraint.