Module: Nerve Disorders

Chye Yew Ng MBChB(Hons) FRCS(Tr&Orth) British Diploma in Hand Surgery

European Board of Hand Surgery DiplomaConsultant Hand & Peripheral Nerve Surgeon

Upper Limb Fellowship Director

Overview

Peripheral nerve injuriesBrachial plexus injuriesCompression neuropathyCRPS

Hierarchical Approach to Revision

Why?(Indications)

What?(Treatment options)

When?(Timing of surgery)

How?(Technical details)

HOTHigher Order

Thinking

Peripheral Nerve Injuries

Cross Section of a Peripheral Nerve

Axon

Fascicle

Nerve

Endoneurium

Epineurium

Perineurium

EpiPEn = Epi – Peri – Endo

A&E

Extrinsic & Intrinsic vascular supplyLongitudinal – Segmental -

Interconnected

Central Neuronal Death & Neuroprotection

Neuronal death after peripheral nerve injury

Acetyl-L-carnitineArrests sensory neuronal deathSpeeds up regeneration

N-acetyl-cysteineProvides sensory and motor neuronal protection Hart et al. Neurological Research 2008

MechanoreceptorsSlowly Adapting Rapidly

Adapting

Cutaneous

Low frequenc

y vibration

Merkeldiscs

Meissnercorpuscle

s

Subcutaneo

us

High frequenc

y vibration

Ruffiniterminals

Paciniancorpuscle

s

Mechanisms of Nerve Injuries

Crush / compression

Stretch / traction

Laceration / transection

Metabolic disturbance

Ischaemia

Radiation

Electrical injury

Thermal injury

Classification of Nerve Injuries

Seddon

BMJ1942

Neurapraxia(Transient Block)

Axonotmesis(Lesion in

Continuity)

Neurotmesis(Division of a

nerve)

Brain1943

• Localised degeneration of the myelin sheaths

• Complete interruption of axons

• Preservation of supporting structures (Schwann tubes, endoneurium, perineurium)

• All essential parts destroyed

• Interruption can occur without apparent loss of continuity

Classification of Nerve Injuries

Neurapraxia Axonotmesis Neurotmesis

Motor - - -Sensory +/- - -Autonom

ic +/- - -NCS

Conduction block at the site

Distal conduction preserved

Loss of conduction both at and distal to the lesion

Loss of conduction both at and distal to the lesion

EMG No fibrillation Fibrillation ++ Fibrillation ++

Recovery

Days to weeks provided the cause is removed

Months provided the cause is removed

No recovery unless repaired

Nerve Conduction StudiesRecording electrode

Neurapraxia

Axonotmesis

Neurotmesis

Wallerian degeneration

Recording electrode

Recording electrode

HOT

In clinical practice, how do you distinguish?

Axonotmesis versus NeurotmesisNature of injury

Serial observations

Exploration

Seddon BMJ 1942

(Imaging)

Nerve in Danger!Pain, Pain, Pain• Burning• Severe

Autonomic dysfunction• Absence of sweating• Smoothness & dryness of skin

Tinel sign• Distal to Proximal• Regenerating touch fibres

Classification of Nerve Injuries

Sunderland

1951I II III IV V

Focalconduction

block

NO Wallerian

degeneration

AxonalDisruption

Axon+

Endoneurium

Disruption

Axon +

Endoneurium+

Perineurium

Disruption

Axon +

Endoneurium+

Perineurium+

EpineuriumDisruption

Cross-innervation

Sunderland ‘VI’

Grabb & Smith’s Plastic Surgery 6th edition. Chapter 9

HOT

Physiological Conduction Block

Type AIntraneural circulatory arrestMetabolic block with no nerve fibre pathologyImmediately reversible

Type BIntraneural oedemaIncreased endoneurial fluid pressureReversible within days or weeks

Classification of Nerve Injuries

Lundborg

1988

Physiological

conduction block

Myelindamage

Axonal damage

Axon +

Endodamage

Axon +

Endo +

Peridamage

Axon +

Endoneurium+

Perineurium+

Epineurium

damage

Type A

Type B

Sunder

land1951

I II III IV V

Seddon

1942Neurapraxia

(Transient Block)

Axonotmesis

(Lesion in Continuity

)

Neurotmesis(Division of a nerve)

Classification of Nerve Injuries

Lundborg

1988

Physiological

conduction block

Myelindamage

Axonal disruptio

n

Axon +

Endo

Axon +

Endo +

Peri

Axon +

Endoneurium+

Perineurium+

Epineurium

Type A

Type B

Sunder

land1951

I II III IV V

Seddon

1942Neurapraxia

(Transient Block)

Axonotmesis

(Lesion in Continuity

)

Neurotmesis(Division of a nerve)

Non-degenerative

Degenerative

HOT

Nerve Surgery

Neurolysis

Nerve repair

Nerve grafting

Nerve transfer

Prerequisites for Nerve Repair

Skeletal stability

Healthy tissue bed

Healthy nerve ends

No undue tension

Adequate soft tissue coverage

Epineurial versus Group Fascicular Repairs

EpineurialLess exactSimple

Group FascicularBetter alignmentMore dissection (scarring)

The functional results of group fascicular repair has not been shown to be more superior than that of epineurial repair.

Lee & Wolfe. Peripheral nerve injury & repair. JAAOS 2000

Prognostic Factors of Outcomes

• Age• DM, alcohol

Patient factors

• Level of injury (distal vs proximal)

• Type of nerve (pure vs mixed)• Condition of nerve ends

Injury factors

• Delay to repair• Length of gap

Surgical factors

Which of the following is false regarding fibrin glue?

a) Fibrin glue is nontoxic and does not block axon regeneration

b) It may be used in combination with suture repair

c) The outcome of fibrin glue repair is inferior to that of suture repair

d) The common components of fibrin sealants include fibrinogen, thrombin and calcium chloride e) It has low tensile strength

Tse & Ko. Nerve glue for upper extremity reconstruction. Hand Clinics 2012

Nerve Grafts/ConduitsAutologous SourceNerve autograftVein (+/- muscle)

Off-the-shelfType I collagenCaprolactonePolyglycolic acid (PGA)Submucosal ECM Processed nerve allograft

Lin et al. Nerve Allografts & Conduits in Peripheral Nerve Repair. Hand Clinics 2013Kaushik & Hammert. Options for Digital Nerve Gap. JHSAm 2015

A 35 year-old male presented with numbness along the radial border of his right index finger 9 months after he sustained a cut in his first web. After surgical exploration and debridement, there is a 3.5cm nerve defect in the radial digital nerve.

What is the most appropriate surgical reconstructive option?

a) Flexion of digit to achieve primary repair before gradual distraction

b) Type I collagen nerve conduit

c) Autologous vein graft

d) Posterior interosseous nerve graft

e) Polyglycolic acid (PGA) conduit

Principles of Motor Nerve Transfers

Donor nerve near target motor end platesExpendable donor nervePure motor donor nerveDonor-recipient size matchDonor function synergy with recipient functionMotor re-education improves function

Mackinnon SE, Novak CB. Hand Clin 1999

Brachial Plexus Injuries

Brachial Plexus Injuries

• Time• Breadth

• Length

• Depth

Severity

(Seddon, Sunderland)

Level(Supra vs

Infraclavicular)

Acutevs

Chronic

Number of

roots(C5-T1)

HOT

Leffert Classification

I OpenII Closed

IIA Supraclavicular Pre-ganglionic Post-ganglionic

IIB InfraclavicularIII Radiation inducedIV Obstetric

IVA Erb’s (upper root)IVB Klumpke’s (lower root)IVC Mixed

Objectives of Examination

Where is the lesion?

What functions are lost?

What functions are present?

How can you improve functions of the limb?

Draw the brachial plexus

C5

C6

C7

C8

T1

C5

C6

C7

C8

T1

MC

MEDIAN

ULNAR

R

Ax

C5

C6

C7

C8

T1

MC

MEDIAN

ULNAR

R

Ax

LTN

C5

C6

C7

C8

T1

MC

MEDIAN

ULNAR

R

Ax

LTN

LPSSDS

C5

C6

C7

C8

T1

MC

MEDIAN

ULNAR

R

Ax

LTN

LPSSDS

USs TD LSs

C5

C6

C7

C8

T1

MC

MEDIAN

ULNAR

R

Ax

LTN

LPSSDS

USs TD LSs

MP MBC MABC

C5

C6

C7

C8

T1

MC

MEDIAN

ULNAR

R

Ax

LTN

LPSSDS

USs TD LSs

MP MBC MABC

Sc

C5

C6

C7

C8

T1

MC

MEDIAN

ULNAR

R

Ax

LTN

LPSSDS

USs TD LSs

MP MBC MABC

Sc

Roots Trunks Divisions Cords Terminal branches

C5

C6

C7

C8

T1

MC

MEDIAN

ULNAR

R

Ax

LTN

LPSSDS

USs TD LSs

MP MBC MABC

Sc

Roots Trunks Divisions Cords Terminal branches

Upper

Lower

Middle

Lateral

Medial

Posterior

Post

erior

PosteriorPosterior

Anterior

Anterior

Ante

rior

Dermatomes

Myotomes

Common Clinical Patterns

Closed traction BPI

Supraclavicular

Upper roots

Total palsy

Infraclavicular

Cord(s)

Terminal branch(es)

Motorcycle accident

Shoulder trauma

Common Clinical Patterns25yo RTA polytraumaNo shoulder motion

No elbow flexionGOOD HAND

25yo RTA polytraumaFLAIL UPPER LIMB

65yo anterior dislocation of shoulder

NO DELTOID

C5, C6

C5 – T1

Axillary nerve

Common Clinical Patterns

25yo RTA polytraumaNo shoulder motion

No elbow flexionGOOD HAND

C5, C6XR neck chest

shoulderMRI cervical spine, BPNCS/EMG at 3 weeks

25yo RTA polytraumaFLAIL UPPER LIMB C5 – T1

XRMRI

NCS/EMG at 3 weeks

65yo anterior dislocation of shoulder

NO DELTOIDAxillary nerve

NCS/EMG at 6 weeks

if no recovery

Pre- versus Post-ganglionic?

ClinicalHorner’s syndromeRhomboid, serratus anterior, paraspinal muscles paralysisAbsent Tinel signHistamine test (historical)

RadiologyPhrenic nerve palsy (raised hemidiaphragm)Cervical transverse process /1st rib♯PseudomeningocelesRootlets abnormalities

NeurophysiologyPreserved SNAP (but insensate)

HOT

Intraoperative Assessment - Is there a graftable nerve

stump?• Direct inspection• PalpationSurgery

• Somatosensory Evoked Potentials(SSEP)

• Motor Evoked Potentials(MEP)Neurophysiolo

gy

• Frozen section (fascicles / scar)• Choline acetyltransferase (CAT)

activity – identify motor fasciclesLaboratory

Timing of Surgery

Emergent- Open injury- Arterial injury- Deteriorating neurology

Early (<3months)- Closed injury- Complete/partial palsy- Neurolysis/grafts/ transfers

Late (>12months)- Muscle transfers- Bony procedures

HOT

Surgical Priorities1 – Restore elbow flexion2 – Restore shoulder abduction & ER (stability)3 – Restore hand functionOther considerations:• Elbow extension• Scapular stability• Sensibility of hand

Common Nerve TransfersPalsy Donor Recipient

C5, 6Spinal accessory Radial (long head of triceps) Ulnar fascicle Median fascicle

SuprascapularAxillary (anterior)Biceps branchBrachialis branch

C5, C6, C7Spinal accessory Intercostals Ulnar fascicle Median fascicle

SuprascapularAxillary (anterior)Biceps branchBrachialis branch

C8, T1Brachioradialis or brachialis branchSupinator branch

AINPIN

Pan-plexus palsy remains an unsolved challenge!

Limited available donorAny graftable rootSpinal accessoryIntercostalsPhrenic nerve (NICE guideline)Contralateral C7HypoglossalDeep cervical plexus

Which recipients (functions) do you target?Future donor for free functioning muscle transfers?

Common Clinical Patterns ?Prognosis

25yo RTA polytraumaNo shoulder motion

No elbow flexionGOOD HAND

C5, C6Regain good elbow flexion, moderate shoulder movementReturn to work

25yo RTA polytraumaFLAIL UPPER LIMB C5 – T1 Poor-to-fair function

Long-term disability

65yo anterior dislocation of shoulder

NO DELTOIDAxillary nerve

Fair-to-good recovery

Compression Neuropathy

What do (I think) you need to learn?

Carpal tunnel syndrome (detailed knowledge)Cubital tunnel syndromeGuyon canal syndromeRadial tunnel syndrome / PIN palsyPronator syndrome / AIN palsy

Carpal Tunnel SyndromeA collection of symptoms and signs due to increased pressure within the carpal tunnel leading to compression of the median nerve

• Pins & needles or Tingling• Numbness• Pain• Weakness or clumsiness• Wasting of thenar muscles

What is the Gold Standard?

CTS

Signs Symptoms

Neurophysiology

Who is affected? Risk Factors

Age: 45- 65Females > malesFamily historyPregnancyMedical conditions: DM, RA, HypothyroidismObesityVibrationAnatomical abnormalities of the wrist

• Southern Sweden 3000 subjects (2466 responded)

• Age 25 – 74Criteria PrevalencePain, numbness and/or tingling in median nerve distribution

14.4%

Clinically certain CTS 3.8%NCS positive 4.9%Clinically & NCS confirmed CTS 2.7%

Atroshi et al JAMA 1999

• Case-control study• UK GP Research Database• 3391 cases (72% women)• Mean age at diagnosis 46 (16-96)• 4 controls matched for age, sex, GP and

duration of available data.

• Smoking, HRT, COCP, CorticosteroidsJHSE 2004; 29: 315-20

JHSE 2004; 29: 315-20

Risk Factor Odds RatioPrevious wrist fracture 2.29Rheumatoid arthritis 2.23

Obesity 2.06Osteoarthritis of wrist/carpus 1.89

Diabetes 1.51Use of insulin 1.52

Sulphonylureas 1.45Metformin 1.20Thyroxine 1.36

Treatment Options

Comments

Nocturnal neutral wrist splint

• Those with night symptoms

Steroid injection • Consider in pregnancy-related CTS• 1 in 4-5 symptom-free at 1 year

Carpal tunnel release

• Complete division of transverse carpal ligament

• Open and endoscopic CTR both equally effective. Endoscopic CTR may be associated with less postoperative pain and earlier return to work but this may not be justifiable by its increased risks of nerve injury and costs (in the NHS).

For CTR, read papers by Gelberman & Atroshi!

15 Hands in 12 patientsAt 6 weeks and 8 months 24% increase in canal volume Palmar displacement +3.5mmNo change in carpal arch width

Richman et al JHSAm 1989

Morphologic changes after release of the transverse carpal ligament

Anatomical variations of the recurrent motor branch of median

nerve

Lanz. JHSAm 1977.Lindley. JHSAm

2003.

16 clinically successful casesAt 1 month,

sensory conduction velocity and distal motor latency improvedCMAP worsened (?post-surgical oedema)

At 6 month, all measures improved

Retrospective study115 patients at mean 10 years post CTR71 asymptomatic → 41 +ve NCS for CTS44 symptomatic → 36 +ve NCS for CTS

Sensory Conduction Velocity

Motor Latency

Classification of failed CTR

Persistent symptoms

Incomplete releaseWrong diagnosis

Recurrent symptoms

Scar/cicatrix formationTenosynovitis

New symptoms Iatrogenic nerve injuryPillar pain

Cubital tunnel syndromeWhat is your preferred surgical treatment for primary cubital tunnel syndrome?

Cubital tunnel syndromeWhat is your preferred surgical treatment for primary cubital tunnel syndrome?

I would perform in-situ decompression because meta-analyses have shown comparable clinical outcomes but lesser complications/morbidity when compared to anterior transposition.

Cubital tunnel syndromeWhat are the indications of anterior transposition?

Cubital tunnel syndromeWhat are the indications of anterior transposition?

• Revision• Subluxation/Instability of ulnar nerve• Poor tissue bed for the nerve• (Elbow trauma surgery)

Sensory branch (after PB)

Ulnar artery aneurysm or thrombosis

Guyon’s canalWhat you need to know?

MixedLEFT HAND

Superficial branch (sensory only after Palmaris brevis)

Ulnar artery aneurysm or thrombosis

Deep motor branch

Ganglion or hook of hamate fracture (zones 1 & 2)

MixedLEFT HAND

Posterior Interosseous Nerve

Radial tunnel syndrome

Pain syndromeEMG normal

PIN palsyMotor deficitEMG abnormal

Common Sites of Compression:Fibrous band btw brachialis & BRRecurrent leash of HenryExtensor carpi radialis brevis edgeArcade of FröhseSupinator muscle edge

Compression versus Neuritis

Entrapment neuropathy

Absent/minimal painSpontaneousProgressive and complete

Neuralgic amyotrophy

Severe painPrecipitant eventSeverity changeable and reversibleMore widespread paralysis and possible sensory disturbance

Hashizume et al JBJSBr 1996; 78: 771-6.

Proximal Median NervePronator syndromePain (forearm) syndromeParaesthesiaEMG/NCS inconclusive

AIN palsyMotor deficit onlyEMG/NCS abnormal

Sites of Compression:Supracondylar processLigament of StruthersLacertus fibrosusBtw two heads of pronator teresFDS arch

Sites of Compression:Tendinous edge of deep head of PTLacertus fibrosusFDS archAccessory head of FPL (Gantzer’s muscle)Accessory muscle from FDS to FDPAberrant muscles (FCRB, palmaris profundus)Thrombosis of ulnar collateral vesselsAberrant radial arteryBicipital bursa

Complex Regional Pain Syndrome

Disproportionate PainSensory changesAbnormal skin color Temperature change Abnormal sudomotor activity OedemaJoint stiffness

EXCLUSION OF OTHER CAUSES!

International Association for Study of Pain

CRPS Type I

Reflex sympathetic dystrophy (RSD)

No definable nerve injury

CRPS Type II

Causalgia

Definable nerve injury

Symptoms NOT restricted to dermatome

CRPS – Budapest Criteria

Management of Suspect CPRS

Prevention (Vitamin C – distal radius fractures)

Treat any treatable cause

Physiotherapy (Desensitisation, mirror therapy)

Pain specialistMultimodal analgesicsRegional blockadeBisphosphonate infusion

Psychology

Summary / Testable Concepts

• Most injuries are mixed• Pain, Autonomic dysfunction & Tinel sign

Peripheral nerve injuries

• 4 dimensions • Timing of surgery• Priorities of reconstruction

Brachial plexus injuries

• Carpal tunnel syndromes (learn everything you can!)

Compression neuropathy

• Budapest criteriaCRPS

Thank you and good luck!

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