upper limb nerve lesions

Radial nerve

aetiology
High lesion (radial n)

·      fracture of humerus

·      fracture or dislocation of shoulder

·      axillary compression

·      back of chair (“Saturday night palsy”)

·      crutch

·      prolonged tourniquet pressure

Low lesion (posterior interosseous n)

·      fracture or dislocation at elbow

·      local wound

·      operation on proximal radius

clinical features
High lesion

·      inability to extend arm (triceps) uncommon

·      lesion usually distal to level of triceps innervation

·      wrist drop (ECRL, ECRB)

·      inability to extend MCP jts of fingers (EDC)

·      inability to extend thumb (EPL, EPB)

·      sensory defect in anatomical snuffbox

Low lesion

·      as above but

·      triceps OK

·      radial deviation with wrist extension (ECU, ECRB, with ECRL intact)

·      no sensory deficit

early treatment

·      open injury

·      explore

·      closed injury

·      lively splint and ROM

·      EMG at 3 weeks

·      explore at 4-5 months if no recovery

tendon transfers
High radial nerve palsy

Requirements

·      wrist extension

·      finger (MCP jt) extension

·      thumb extension and abduction

·      ignore sensory loss

Available muscles

·      all extrinsics innervated by median and ulnar nerves (many)

Transfers

·      basis is use of PT for wrist flexion

·      classic Jones transfer uses FCU to restore finger extension

·      removes it as ulnar stabiliser

·      may lead to radial deviation

·      esp. if posterior interosseous palsy, as ECRL functioning

·      also uses FCR for thumb extension

·      thus removes both wrist flexors

·      alternative is Starr transfer

·      FCR for wrist extension

·      PL for thumb extension

·      preferred by Green

·      another option is Boyes transfer

·      FDS III to EDC and IV to EPL

·      through interosseous membrane

·      useful when PL absent

Jones transfer

·      PT to ECRL and ECRB

·      FCU to EDC III-V

·      FCR to EIP, EDC II, EPL (+/- EPB, APL)

·      problem is that both wrist flexors are transferred

FCR (Starr) transfer

·      PT to ECRB

·      FCR to EDC

·      PL to rerouted EPL

Technique of Starr transfer

PT transfer

·      origin of PT elevated with strip of periosteum

·      PT freed proximally

·      passed around radial border of forearm in subcutaneous tunnel to dorsal surface

·      intertwined into ECRB tendon

FCR transfer

·      FCR tendon transected near insertion

·      passed around radial border of forearm in subcutaneous tunnel to dorsal surface

·      EDC tendons divided and transposed superficially to extensor retinaculum

·      EDC tendons anastomosed end-to-end with FCR

PL transfer

·      PL tendon transected near insertion

·      EPL tendon indentified and divided at musculotendinous junction

·      rerouted out of Lister’s canal toward volar aspect across anatomical snuffbox

·      makes EPL abductor and extensor

·      PL and EPL anastomosed

·      if PL absent, EPL joined with EDC to FCR transfer

Posterior interosseous nerve palsy

Requirements

·      as for radial nerve except wrist extension not required

Transfers

·      as for radial nerve except PT transfer not required

Association with fracture of humerus

·      options are

·      early exploration

·      exploration at 6-8 weeks

·      late exploration

·      initial stages of recovery may take 4-5 months

·      before function in BR or ECR detected

·      best option is to wait 4-5 months and then explore if no return of function (Green)

·      exceptions are

·      open fractures

·      failure of closed treatment to maintain satisfactory alignment

·      associated vascular injuries

·      loss of function after manipulation of fracture

Ulnar nerve

aetiology
High lesion (at or above elbow)

·      usually at elbow

·      elbow fracture or dislocation

·      compression at elbow

·      esp. anaesthetised or bedridden patients

·      entrapment in cubital tunnel

·      esp. with valgus elbow

Low lesion (below elbow)

·      usually at wrist

·      laceration at wrist

·      entrapment in ulnar tunnel (Guyon’s canal)

·      esp. in cyclists

·      penetrating forearm wound

Clinical features
High lesion

·      as for low lesion but

·      less clawing (ulnar 1/2 of FDP paralysed)

·      weak wrist flexion

Low lesion

·      claw hand deformity

·      hyperextension of MCP jts and flexion of IP jts of ring and little fingers

·      weakness of lumbricals with loss of MCP flexion and IP extension

·      unopposed MCP extension by extensors and IP flexion by flexors

·      less marked in high lesion because ulnar FDP paralysed (paradoxical ulnar claw)

·      weak finger abduction

·      weak finger adduction

·      positive paper grip test

·      weak thumb adduction

·      positive Froment’s sign (IP flexion)

·      hypothenar and interosseous wasting

·      numbness of ulnar 1 1/2 fingers

·      numbness of ulnar dorsum of hand

·      if lesion proximal to dorsal branch

early Treatment

·      open injury

·      explore and repair

·      anterior transposition provides 5 cm length

·      closed injury

·      knuckle duster splint and ROM

·      EMG at 3 weeks

·      explore a 6 weeks

·      entrapment

·      observe for 3 months

·      decompress if fails to settle

tendon transfers
High ulnar nerve palsy

Requirements

·      correct clawing

·      index abduction

·      thumb adduction

·      DIP flexion of ring and little fingers

·      ulnar wrist flexion (not important)

·      sensation on ulnar border of hand

Transfers

Claw fingers

·      Zancolli capsulodesis

·      modified Bunnell FDS transfer

Thumb adduction

·      ECRB (with free graft) between 2nd and 3rd metacarpals to insertion of AP

Index abduction

·      EPB to tendon of 1st DI

DIP flexion

·      tenodesis of middle FDP to ring and little FDP

Technique of capsulodesis

·      transverse palmar incision

·      each A1 pulley opened

·      flexor tendons retracted

·      volar plate incised beneath MC head

·      two lateral incisions made

·      volar capsule advanced proximally

·      finger flexed to 20o

·      volar plate sutured to new position

·      mild flexion contracture of MCP jt created

Technique of FDS transfer

·      use middle or ring finger

·      midlateral incision along radial side of finger

·      tendon sheath opened

·      FDS tendon released

·      transverse proximal incision at proximal palmar crease

·      FDS tendon identified and withdrawn

·      tendon split into 4 tails

·      radial midlateral incision along radial side of other fingers

·      extensor aponeurosis identified

·      each tail of tendon passed

·      through lumbrical canal

·      volar to deep transverse MC ligament

·      over oblique fibres of extensor apparatus

·      to dorsum of extensor apparatus

·      flex MCP jts 90o and PIP jts at neutral

·      suture each tail to aponeurosis under some tension

Low ulnar nerve palsy

Requirements

·      as above except do not need DIP flexion

Median nerve

aetiology
High lesion

·      elbow fracture or dislocation

·      forearm fracture

·      penetrating forearm wound

Low lesion

·      laceration at wrist

·      fracture of distal radius

·      carpal dislocation

·      entrapment in carpal tunnel

clinical features
High lesion

·      as for low lesion PLUS

·      paralysis of

·      superficial finger flexors

·      deep finger flexors to radial fingers

·      long thumb flexor

·      radial wrist flexor

·      forearm pronators

·      results in Benedictine sign

·      index finger straight

·      ulnar fingers flexed

·      middle finger flexed because middle FDP closely attached to ring FDP

·      interosseous nerve palsy gives

·      Benedictine sign

·      paralysis of radial FDP and FPL

·      weakness of pronation (quadratus)

·      no thenar weakness

·      no sensory loss

Low lesion

·      paralysis of AbPB

·      wasting of thenar eminence

·      numbness in radial 3 1/2 fingers and palm

early treatment

·      open

·      explore and repair

·      closed

·      reduce fracture or dislocation

·      explore if fails to improve

tendon transfers
High median nerve palsy

Requirements

·      index and middle flexor power

·      flexor power in thumb IP

·      thumb opposition

·      sensation thumb and radial index

Transfers

Extrinsic

·      ECRL to FDP (index and middle)

·      BR to FPL

Intrinsic

·      opponensplasty

·      many options

·      best is transfer of EIP

Technique of opponensplasty

·      incision over index MCP j

·      EIP divided with some extensor hood

·      hood repaired

·      second incision over dorsum of hand to free EIP from EDC

·      incision over dorsoulnar wrist to displace tendon ulnarward

·      tendon passed subcutaneously around ulnar aspect of wrist to pisiform

·      then tunnelled across palm to thumb MCP jt

·      tendon interweaved into AbPB tendon and into EPL tendon

Other lesions

Axillary nerve
Aetiology

·      dislocation of shoulder

·      proximal humeral fracture

·      brachial plexus injury

·      deltoid-splitting approach

Clinical features

·      weakness of shoulder abduction

·      abduction still may be possible by supraspinatus

·      numbness in regimental patch area

Treatment

·      usually resolves following fracture or dislocation

·      exploration if fails to recover within 3 months

·      may require shoulder arthrodesis

long thoracic nerve

·      C5,6,7

·      runs down posterior axillary wall

·      supplies serratus anterior

Aetiology

·      surgery

·      shoulder or neck operations

·      1st rib resection

·      mastectomy

·      carrying loads on shoulder

Clinical features

·      winging of scapula

Treatment

·      stabilisation of scapula by transferring pectoralis major or minor to lower part

spinal accessory nerve

·      C3,4

·      supplies sternocleidomastoid

·      then runs in posterior triangle of neck to supply trapezius (upper half)

Aetiology

·      stab wounds to neck

·      operations on posterior triangle

·      esp. lymph node biopsy

·      traction injuries

Clinical features

·      sagging of shoulder

·      inability to shrug

Treatment

·      if open, immediate exploration and repair

·      if closed, wait 6 weeks for recovery

·      if no recovery, explore to

·      confirm diagnosis

·      repair by suture or grafting

suprascapular nerve

·      C5,6

·      runs through suprascapular notch

·      supplies supraspinatus and infraspinatus

Aetiology

·      fracture of scapula

·      direct blow to superior border of scapula

·      traction

·      carrying heavy load

Clinical features

·      scapular pain

·      weakness of external rotation of shoulder

·      may be confused with rotator cuff disease

Treatment

·      usually resolves

·      may respond to decompression by division of suprascapular ligament