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Purpose: Deformities of the spastic upper limb result frequently from the association of spasticity, muscle contracture and muscle imbalance between strong spastic muscles and weak non-spastic muscles. This study was designed to evaluate the feasibility of combining selective neurectomy of the usual spastic and strong muscles together with transfer of their motor nerves to the usual weak muscles, to improve wrist and fingers motion while decreasing spasticity., Methods: Twenty upper limbs from fresh frozen human cadavers were dissected. All motor branches of the radial and median nerve for the forearm muscles were identified. We attempted all possible end-to-end nerve transfers between the usually strong "donor" motor branches, namely FCR and PT, and the usually weak "recipient" motor branches (ERCL, ECRB, PIN, AIN)., Results:  The PT had two nerve branches in 80%, thus allowing selective neurectomy. The proximal PT branch could be anastomosed end-to-end in 45% (AIN) to 85% (ECRL) of cases with the potential recipient branches. The distal PT branch could be anastomosed end to end to all potential recipient nerves. The FCR had a single branch in all cases. End-to-end anastomosis was possible in 90% for the ECRL and in 100% for all other recipient branches, but sacrificed all FCR innervation, ruling out hyperselective neurectomy., Conclusion:  Selective neurectomies can be associated with distal nerve transfers at the forearm level in selected cases. The motor nerve to the PT is the best donor for nerve transfer combined with selective neurectomy, transferred to the ECRL, ECRB, PIN or AIN., (© 2022. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Purpose: Nerve transfers represent an innovative tool in the surgical treatment of upper limb paralysis. Well-documented for brachial plexus sequalae and under evaluation for tetraplegic patients, they have not yet been described for spastic upper limbs. The typical spastic deformity involves active and spastic flexor, adductor and pronator muscles, associated with paralysed extensor and supinator muscles. Experience with selective neurectomy has shown an effective decrease in spasticity together with preservation of muscle strength. We conceptualized a combination of neurectomy and nerve transfer, by performing a partial nerve transfer from a spastic elbow flexor muscle to a paralyzed wrist extensor muscle, hypothesizing that this would reduce the spasticity of the former and simultaneously activate the latter., Methods: Ten cadaveric dissections were performed in order to establish the anatomic feasibility of transferring a motor branch of the brachioradialis (BR) onto the branch of the extensor carpi radialis longus (ECRL) or brevis (ECRB). We measured the emergence, length, muscle entry point and diameter of each branch, and attempted the transfer., Results: We found 1-4 motor nerve for the BR muscle and 1-2 for the ECRL muscle. In all cases, the nerve transfer was achievable, allowing a satisfactory coaptation. The ECRB branch emerged too distally to be anastomosed to one of the BR branches., Conclusion: This study shows that nerve transfers from the BR to the ECRL are anatomically feasible. It may open the way to an additional therapeutic approach for spastic upper limbs., (© 2021. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Purpose: Spasticity of the first web space is common in upper limb spasticity. Selective neurectomy is one of the treatments that can reduce spasticity. The purpose of this study was to describe the variations of the deep motor branch of the ulnar nerve for the adductor pollicis (AP) and the first dorsal interosseous muscle (DIO) to assess the feasibility of selective neurectomy and suggest an ideal surgical approach., Methods: The deep branch of the ulnar nerve (DBUN) was dissected in 21 hands. Measurements included the distance between the point of passage of the DBUN between the two heads of the adductor and three anatomical landmarks: the bi-styloid line, the flexor carpi radialis and the pisiform bone, and the number and mode of divisions of each branch., Results: The point of passage of the DBUN between the two heads of the adductor is very constant respective to the landmarks. The DBUN gives off 1-3 branches each for the oblique head of the AP, the transverse head, and the first DIO. Muscles receive more than one branch in 95% cases for the oblique head and 62% of cases for the transverse head, and 100% for the DIO., Conclusions: This anatomical study suggests that selective neurectomy is feasible for the AP and first DIO muscles in most cases. An ideal approach for selective neurectomy of these muscles should start from the point of passage of the DBUN between the two heads of the AP. This point is easily identified with the help of the described landmarks.

Purpose: The median nerve is responsible for the motor innervation of most of the muscles usually involved in upper limb spasticity. Selective neurectomy is one of the treatments utilized to reduce spasticity. The purpose of this study was to describe the variations of the motor branches of the median nerve in the forearm and draw recommendations for an appropriate planning of selective neurectomy., Materials and Methods: The median nerve was dissected in the forearm of 20 fresh cadaver upper limbs. Measurements included number, origin, division, and entry point of each motor branch into the muscles., Results: One branch for the pronator teres was the most common pattern. In 9/20 cases, it arose as a common trunk with other branches. A single trunk innervated the flexor carpi radialis with a common origin with other branches in 17/20 cases. Two, three or four branches innervated the flexor digitorum superficialis, the first one frequently through a common trunk with other branches. They were very difficult to identify unless insertions of pronator teres and flexor digitorum superficialis were detached. The flexor digitorum profundus received one to five branches and flexor pollicis longus one to two branches from the anterior interosseous nerve., Conclusions: There is no regular pattern of the motor branches of the median nerve in the forearm. Our findings differ in many points from the classical literature. Because of the frequency of common trunks for different muscles, we recommend the use of peroperative electrical stimulation. Selective neurotomy of flexor digitorum superficialis is technically difficult, because the entry point of some of their terminal branches occurs just below the arch and deep to the muscle belly.

Purpose: Precise knowledge of motor nerve branches is critical to plan selective neurectomies for the treatment of spastic limbs. Our objective is to describe the muscular branching pattern of the ulnar nerve in the forearm and suggest an ideal surgical approach for selective neurectomy of the flexor carpi ulnaris., Methods: The ulnar nerve was dissected under loop magnification in 20 upper limbs of fresh frozen cadavers and its branches to the flexor carpi ulnaris muscle (FCU) and to the flexor digitorum profundus muscle (FDP) were quantified. We measured their diameter, length and distance between their origin and the medial epicondyle. The point where the ulnar artery joined the nerve was observed. The position in which the ulnar nerve gave off each branch was noted (ulnar, posterior or radial) and the Martin-Gruber connection, when present, had its origin observed and its diameter measured., Results: The ulnar nerve gave off two to five muscular branches, among which, one to four to the FCU and one or two to the FDP. In all cases, the first branch was to the FCU. It arose on average 1.4 cm distal to the epicondyle, but in four specimens it arose above or at the level of the medial epicondyle (2.0 cm above in one case, 1.5 cm above in two cases, and at the level of the medial epicondyle in one). The first branch to the FDP arose on average 5.0 cm distal to the medial epicondyle. All the branches to FDP but one arose from the radial aspect of the ulnar nerve. A Martin-Gruber connection was present in nine cases. All motor branches arose in the proximal half of the forearm and the ulnar nerve did not give off branches distal to the point where it was joined by the ulnar artery., Conclusions: The number of motor branches of the ulnar nerve to the FCU varies from 2 to 4. An ideal approach for selective neurectomy of the FCU should start 4 cm above the medial epicondyle, and extend distally to 50% of the length of the forearm or just to the point where the ulnar artery joins the nerve.

Purpose: Spastic flexion deformity of the elbow is mainly mediated by the biceps brachii and the brachialis muscles, innervated by the musculocutaneous nerve. Selective neurectomy of the musculocutaneous nerve showed promising results to relieve excessive spasticity in the long term but lacks of a consensual surgical strategy. The aim of the study was to describe the distal branching pattern of the motor branches of the musculocutaneous nerve in an attempt to develop guidelines for surgery., Methods: Sixteen arms of fresh cadaver specimen were dissected. We recorded the site of each primary and terminal motor branch as a percentage of the distance from the coracoid process to the lateral epicondyle., Results: The biceps muscle was innervated by one to five primary motor branches. The first branch emerged from the nerve at an average of 37.1% of the arm length, and the most distal terminal branch at 55.7%. The brachialis muscle received one to three primary branches. The first branch exited the nerve at an average of 51.7% of the arm length and the last terminal branch at 69.3%. The average number of terminal branches dedicated to the biceps and the brachialis muscles were, respectively, 7.9 and 6.5., Conclusions: According to our findings, we recommend to dissect the musculocutaneous nerve between 18 and 75% of the distance between the coracoid process and the lateral epicondyle to identify the motor terminal branches to the biceps brachii and the brachialis muscle, sparing sensory branches.