You Want to Do Your First Nerve Transfer Christopher J

SYM18: You Want To Do Your First Nerve

Transfer

Moderator(s): Amy M. Moore, MD

Faculty: Stacy Baker, MOT, OTR/L, CHT, Jayme A. Bertelli, MD, PhD, and Christopher J. Dy, MD, MPH, FACS

Session Handouts Saturday, October 03, 2020

75TH VIRTUAL ANNUAL MEETING OF THE ASSH OCTOBER 1-3, 2020

822 West Washington Blvd Chicago, IL 60607 Phone: (312) 880-1900 Web: www.assh.org Email: [email protected]

All property rights in the material presented, including common-law copyright, are expressly reserved to the speaker or the ASSH. No statement or presentation made is to be regarded as dedicated to the public domain.

Nerve Transfers

Amy M. Moore, MD, Plastic and Reconstructive Surgery The Ohio State University

I. Introduction Following high nerve injuries, motor and sensory recovery can be less than optimal. Nerve transfers can provide a distal source of motor and/or sensory innervation closer to the target end organ which allows faster recovery and improved outcome. This course will focus on the use of nerve transfers to restore function. It will include discussion on patient selection, surgical options and techniques (including demonstrative videos/case presentations).

Nerve transfer (def) – transfer of an expendable donor nerve or fascicle to a denervated recipient nerve to restore function to the recipient end-organ (skin for sensation or muscle for motor).

Benefits: 1. Performed closer to recipient target allowing for earlier reinnervation. 2. Can be performed outside of the zone of injury and scarred field. 3. Can be performed on patients with delayed presentations. 4. Avoids interposition nerve grafting which fosters increased regenerating nerve fibers making it to the target end-organ. (1, 2)

Goal: Reinnervation of the target muscle within 12-18 months to avoid irreversible atrophy (3, 4).

Classification of Nerve Injuries

TINEL'S DEGREE OF RATE OF SURGICAL SIGN RECOVERY INJURY RECOVERY PROCEDURE PRESENT

Up to 12 I Neurapraxia No Complete None Weeks

II Axonotmesis Yes Complete 1" per month None

None or III Yes Varies* 1" per month Neurolysis

Neuroma In- Yes, but no Nerve repair, IV None None Continuity advancement graft, or transfer Yes, but no Nerve repair, V Neurotmesis advancement None None graft, or transfer

Some Some Depends on Neurolysis, Mixed Injury VI fascicles fascicles degree of nerve repair, (I to V) (II,III) (II,III) injury (I-V) graft, or transfer

* Recovery can vary from excellent to poor depending on the amount of scarring and the sensory versus motor axon misdirection to target receptors

Principles of nerve transfers: 1. History and Physical Exam: a. Timing from injury b. Extent of involvement (level and degree of nerve injury) c. Current functional limitations d. Presence of potential donor nerves

2. Donor Selection: a. expendable motor nerve b. close to the motor end plates of the target muscle c. large number of motor nerve axons and MRC grade 4 strength d. synergistic muscle function - motor reeducation more straightforward

3. Preoperative Studies: a. EMG/NCS – at 10-12 weeks post injury i. identify extent of injury and recovery ii. identify donors intact

Pearls and Pitfalls: • Remind anesthesiologist—no long acting paralytics • Short or no tourniquet use to avoid neurapraxia and inability to stimulate nerves • Evaluate recipient with nerve stimulator before transection • Evaluate donor with nerve stimulator to confirm function and strength • “Donor DISTAL, Recipient PROXIMAL” • Perform coaptations without tension.

II. A list of common injury patterns and treatment options (both nerve transfer and traditional treatment options):

Upper plexus injury—loss of elbow flexion: • Double fascicular nerve transfer (from median and ulnar nerves to biceps and brachialis nerve branches) • Transfer of triceps, latissimus or pectoralis nerve branches to the elbow flexors; Steindler flexorplasty, long nerve grafts

Upper plexus injury—loss of shoulder function: • Spinal accessory nerve to suprascapular nerve and triceps to deltoid nerve branch transfers • Shoulder fusion, Saha procedure, long nerve grafts

Lower plexus injury—loss of pronation • Brachialis or extensor carpi radialis brevis (if C7 is spared) to pronator nerve branch transfer • Biceps, brachioradialis or brachialis muscle rerouting

Lower plexus injury—loss of thumb and index finger flexion • Supinator branch to anterior interosseous nerve transfer • Brachialis branch to anterior interosseous nerve transfer • Tendon transfers (brachioradialis to flexor pollicis longus and extensor carpi radialis longus to index flexor digitorum profundus)

Axillary nerve injury • Triceps, medial pectoral or thoracodorsal nerve to axillary nerve transfer • Shoulder fusion, long nerve grafts

Radial nerve injury • Median (flexor carpi radialis, flexor digitorum superficialis branches) to radial (extensor carpi radialis brevis and posterior interosseous nerve branches) nerve transfers • Tendon transfers (pronator teres to extensor carpi radialis brevis, palmaris longus to extensor pollicis longus, and flexor carpi ulnaris, flexor carpi radialis or flexor digitorum superficialis to extensor digitorum communis)

Loss of median innervated pronation • extensor carpi radialis brevis to pronator teres branch • Biceps, brachialis or brachialis muscle rerouting

Loss of median innervated thumb and finger flexion • Supinator or brachialis to anterior interosseous nerve branch (combine w/ tenodesis of long to ring/small flexors) • Tendon transfers (brachioradialis or extensor carpi radialis longus to flexor pollicis longus and side to side tenodesis with ulnar flexor digitorum profundus or extensor carpi radialis longus to index/long flexor digitorum profundus)

Isolated AIN injury • flexor digitorum superficialis to anterior interosseous nerve branch • brachioradialis to flexor pollicis longus tendon transfer and flexor digitorum profundus tenodesis, fusion of interphalangeal joint of thumb

Distal median nerve injury • AIN to median motor branch • Opponensplasty

Distal ulnar nerve injury • anterior interosseous nerve to ulnar nerve deep motor branch • Static and dynamic claw hand correction procedures

III. Nerve Transfers to Restore of Elbow Flexion (Musculocutaneous Nerve)

Double Fascicular Transfer – our preferred operation when hand function is preserved. a. FCU fascicle to biceps branch of musculocutaneous b. FCR/FDS fascicle to brachialis branch of musculocutaneous

Figure 1. Double fascicular transfer demonstrating FCU fascicle to biceps branch and FCR fascicle to brachialis branch of musculocutaneous nerve

Pearls and Pitfalls: • Use handheld stimulator to identify donor fascicles as well as to ensure adequate function is remaining in the donor nerve • Avoid downgrading function of donor – ensure MRC grade 4 strength • Understand the topography of the median and ulnar nerves in the upper arm. Hint: the donor fascicles on ulnar and median nerve face each other. • Neurolyse the LABC branch away from coaptation to avoid axon loss down the sensory pathway. • “Donor DISTAL, Recipient PROXIMAL” • Perform coaptations without tension.

IV. Nerve Transfers to Restore Radial Nerve Function

Key Points • Patient Selection is key: Needs to be willing to wait for reinnervation window of 6-9 months (in contrast to 4-8 weeks with tendon transfers) • As with tendon transfers – synergistic transfers should be performed: FCR/PL to PIN and FDS to ECRB • Tensionless repair

V. High Median Nerve Injury

Nerve Transfers to restore hand function 1. Brachialis branch to anterior interosseous nerve transfer.(8) a. For patients with intact, strong elbow flexion b. Restores FPL and FDP to the index (and sometimes long finger) c. While coaptation is performed at level of arm, more extensile dissection of median nerve and branches is often required to avoid inadvertent innervation of non-critical median fascicles (sensory, FDS/FCR or other branches)

Figure 5. Transfer of the brachialis branch to the anterior interosseous nerve.

VI. Sensory Nerve Transfers

Sensory donor nerve a. non-critical sensory distribution b. pure sensory nerve c. good size match between donor and target nerve d. common sensory nerve transfers e. Nerve to the 4th webspace to 1st web space transfer to restore sensation to the radial side of the index and ulnar side of the thumb f. End-to-side repair of 2nd and 3rd web space to ulnar digital nerve to the small to restore sensation to the 2nd and 3rd web spaces g. End-to-side repair of ulnar sensory and dorsal ulnar sensory nerves to median nerve to restore sensation to the small and ring fingers and ulnar dorsal skin

VII. Tips and Pearls of Nerve Transfers

“Donor distal, recipient proximal”:

• this concept is crucial to ensuring adequate length is obtained • the donor nerve is cut at it’s distal-most useful portion • the recipient nerve is divided proximally enough so that it can be mobilized • this avoids interpositional grafts, which could substantially downgrade results

Tension-free repair: • nerve repair must be tension-free and allow full passive range of motion at the time of surgery • tension will dramatically downgrade the functional outcome

Align fascicles of the same modality (motor or sensory): • crucial for successful recovery of function

Natural cleavage planes: • between critical fascicle groups • often identified by prominent longitudinal microvessels • can also be identified by tapping micro-forceps gently across the transverse diameter of the nerve • the forceps will “fall” into the natural cleavage plane

End-to-Side Repairs: • A: motor donor nerves must be subjected to axotomy or a compressive stimulus for clinically relevant and timely regeneration to occur through an end-to-side repair • B: sensory nerves demonstrate spontaneous collateral sprouting which can occur without axonal injury to the donor nerve o The greater the perineurial window, the greater the collateral sprouting

Figure 6. Types of end-to-side repairs.

VIII. Rehabilitation following Nerve Transfers (9)

1. Early Post-operative Management • Early range of motion is important to prevent adhesions at the nerve repair site • Postoperative dressing is removed 2 to 3 days following surgery and begin active/passive range of motion of uninvolved joints • Protect repair site with a splint or sling for 7-14 days • Following immobilization - regain and maintain full passive range of motion • If tendons are transferred or repaired concomitantly then these tendon procedures dictate the immobilization (4 weeks shoulder immobilization if pectoralis major resuspended)

2. Late Stage Rehabilitation - Sensory & Motor Reeducation • Alteration in cortical mapping following nerve injury • Following reinnervation, can regain cortical area by increasing the sensory/motor input • motor re-education: need to increase muscle strength and central mechanisms controlling motor function • nerve-to-nerve transfer – requires motor re-education similar to that required with tendon transfers • biofeedback more useful than muscle stimulation • to facilitate re-learning, begin on unaffected side • initially need to contract muscle from donor nerve to achieve a contraction in the recipient muscle • aim for control and initiation of muscle contraction • be aware of unwanted co-contraction of antagonistic muscles • biofeedback – visual and audio • begin in gravity assisted or gravity eliminated positions and progress to exercises against gravity and progressive resisted exercises • dissociate target muscle from donor muscle contraction • strengthen uninjured muscles weakened from disuse (i.e. scapular muscles)

Pearls and Pitfalls: Sensory reeducation • Begin by increasing the sensory input to the appropriate sensory distribution with different textures of material • Progress to localization exercises and finally discriminatory tasks • Cortical retraining requires repetition and purposeful movement

Motor reeducation • need to increase muscle strength and central mechanisms controlling motor function • nerve to nerve transfer – requires motor reeducation similar to that required with tendon transfers • restore muscle balance – be aware of co-contraction of antagonist muscles, strengthen muscles weakened by disuse • biofeedback more useful than muscle stimulation

References

Also see: http://nervesurgery.wustl.edu/Pages/default.aspx

1. Tung TH, Mackinnon SE. Nerve transfers: indications, techniques, and outcomes. The Journal of hand surgery. 2010;35(2):332-41. Epub 2010/02/10. doi: 10.1016/j.jhsa.2009.12.002. PubMed PMID: 20141906. 2. Moore AM. Nerve Transfers to Restore upper Extremity Function: A Paradigm Shift. Frontiers in neurology. 2014;5:40. doi: 10.3389/fneur.2014.00040. PubMed PMID: 24744749; PubMed Central PMCID: PMC3978351. 3. Boyd KU, Nimigan AS, Mackinnon SE. Nerve reconstruction in the hand and upper extremity. Clinics in plastic surgery. 2011;38(4):643-60. Epub 2011/10/29. doi: 10.1016/j.cps.2011.07.008. PubMed PMID: 22032591. 4. Lee SK, Wolfe SW. Nerve transfers for the upper extremity: new horizons in nerve reconstruction. The Journal of the American Academy of Orthopaedic Surgeons. 2012;20(8):506-17. Epub 2012/08/03. doi: 10.5435/JAAOS-20-08-506. PubMed PMID: 22855853. 5. Colbert SH, Mackinnon SE. Nerve transfers for brachial plexus reconstruction. Hand clinics. 2008;24(4):341-61. doi: 10.1016/j.hcl.2008.07.001. PubMed PMID: 18928885. 6. Belzberg AJ, Dorsi MJ, Storm PB, Moriarity JL. Surgical repair of brachial plexus injury: a multinational survey of experienced peripheral nerve surgeons. J Neurosurg. 2004;101(3):365-76. Epub 2004/09/09. doi: 10.3171/jns.2004.101.3.0365. PubMed PMID: 15352592. 7. Merrell GA, Barrie KA, Katz DL, Wolfe SW. Results of nerve transfer techniques for restoration of shoulder and elbow function in the context of a meta-analysis of the English literature. The Journal of hand surgery. 2001;26(2):303-14. Epub 2001/04/03. doi: 10.1053/jhsu.2001.21518. PubMed PMID: 11279578. 8. Ray WZ, Yarbrough CK, Yee A, Mackinnon SE. Clinical outcomes following brachialis to anterior interosseous nerve transfers. J Neurosurg. 2012;117(3):604-9. Epub 2012/07/24. doi: 10.3171/2012.6.JNS111332. PubMed PMID: 22817905. 9. Moore AM, Novak CB. Advances in nerve transfer surgery. Journal of hand therapy : official journal of the American Society of Hand Therapists. 2014;27(2):96-104; quiz 5. doi: 10.1016/j.jht.2013.12.007. PubMed PMID: 24513183.

Is this patient a good candidate? SYM18: You Want To Do Your First Nerve Transfer Christopher J. Dy, MD MPH FACS Washington University Orthopedics @ChrisDyMD

DISCLOSURES

Christopher J. Dy, MD, MPH, FACS

Speaker has no relevant financial relationships with commercial interest to disclose.

KEY QUESTIONS

1. What is the natural history of this injury? 2. Is reinnervation still possible? 3. Will nerve transfers compromise other options? 4. Is re-education feasible? 5. What is the patient’s timeframe?