With the triple-deposit method the nerve can be successfully blocked. MRI showed a wide variability as to where the musculocutaneous nerve leaves the axillary sheath. These findings could be explained by analysis of the MRI distribution patterns. This thesis demonstrated that the triple-deposit method has a higher block success and shorter onset time compared with the single- or double-deposit method. Particularly, we investigated whether differences in block success could be explained by differences in local anaesthetic distribution as observed by MRI. In the present thesis the triple-deposit axillary block method was evaluated by clinical tests and with MRI.
In clinical practice this triple-deposit method showed promising block effect on the nerves of the brachial plexus that innervate the upper extremity. Trygve Kjelstrup, MD, has developed an axillary brachial plexus block technique that combines the insertion of a catheter with a double transarterial injection technique. We conclude that an axillary plexus block performed with the triple-deposit technique is preferable as compared to the single- and double-deposit method. Clinical accuracy in defining the insertion point is critical. Although the trajectory is close to the plexus, any medial deviation carries the risk of pleural or subclavian vessel contact at other depths. In conclusion, there is a small probability that the needle may reach the pleura when a vertical infraclavicular brachial plexus block is performed, particularly in women, and a high probability that it will contact the subclavian vein or artery. The trajectory had a median distance to the plexus (closest aspect) of 1 mm (range, 0-9 mm) and contacted the nerves in 9 subjects. The subclavian vein was reached by the trajectory in three and the subclavian artery in five subjects. However, pleural contact could be avoided in all subjects by halting needle advancement after contact with the subclavian vessels, plexus, or first rib. The trajectory aimed at the lung in six subjects, five of whom were women. We studied the risk of pneumothorax and subclavian vessel puncture and the precision of this method by using magnetic resonance imaging in 20 adult volunteers. The recommended needle trajectory for the vertical infraclavicular brachial plexus block is anteroposterior, caudad to the middle of the clavicle. Brachial plexus block was performed with a high success rate and is considered a safe alternative to the classically described techniques. The surface landmarks based on bony prominences were defined easily. Conclusion: The new landmarks were not dependent on patients' physical features or deeper anatomic structures. No major complication such as pneumothorax or accidental intravascular insertion was observed. Brachial plexus block was performed with a high success rate (98.5%) and minor complications including phrenic nerve palsy (45%), Horner syndrome (15%), and recurrent nerve block (1.6%). Results: The characteristics of the block resemble those in the interscalene technique. Materials and methods: Brachial plexus block was performed in 60 healthy adult patients undergoing elective Surgery on an upper extremity using the above-mentioned new surface landmarks. The aim of the present study was to determine the clinical efficacy of these suggested landmarks. The needle insertion site was the point between the clavicular one-third and cervical two-thirds of this line. Aim: The line from the midpoint of the sternocleidomastoid muscle to the midpoint of the clavicle was considered the surface projection of the brachial plexus in the supraclavicular region in a previous report using radiological and anatomic techniques.
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