Neuromuscular Diseases A Practical Guideline - part 4 pps

The lower segmental ventraland dorsal lumbar and sacral nerve roots form the cauda equina.. 3 Teres minor muscle Del-This is trial version www.adultpdf.com... Mainly in association with

The conus medullaris terminates at vertebrum L1 The lower segmental ventral

and dorsal lumbar and sacral nerve roots form the cauda equina

The lumbar nerve roots run obliquely downwards and laterally The sacral

spinal nerves divide into rami within the spinal canal Each ramus passes

through a pelvic sacral foramen to join the sacral plexus; each dorsal ramus

emerges through a dorsal sacral foramen to supply paraspinal muscles and the

skin over the sacral and medial gluteal areas

The cauda equina is loosely enveloped by arachnoid membrane, from which

a sleeve extends to cover each nerve root As a nerve passes into the nerve

foramen it is invested in a short sleeve of dura

Acute central (disc) herniation:

Pain bilaterally in the buttock, sacral, perineal, and posterior leg regions, and

Weakness of S1 and S2 muscles, sensory loss from soles to perineal region with

saddle anesthesia Loss of anal wink

Roots positioned most laterally (lower lumbar and upper sacral) are most

often affected, while the central roots can be spared (S3–S5) Thus, the bladder

is often spared

Chronic:

Similar signs as acute injury

Muscle wasting in chronic conditions may resemble chronic polyneuropathy

Toxic:

Anesthesia (spinal and epidural anesthesia)

Contrast media

Cytotoxic drugs (intrathecal methotrexate)

Radiation: TRI (transient radicular irritation)

Bechterew’s disease

Neoplastic:

EpendymomaNeurofibromaRare: dermoid, hemangioblastoma, lipoma, meningioma, paragangliomas,schwannoma

Malignant disease: astrocytoma, bone tumors, leptomeningeal carcinomatosis,metastases, multiple myeloma

Acute central disc protrusion:

A large acute central disc may cause acute and dramatic bilateral sciatic pain.Also pain in the buttock and perineal regions, numbness and weakness of thelegs, and sphincter dysfunction “Saddle anesthesia”

Chronic central disc:

Mimics tumors of the conus medullaris and is associated with perineal pain,paresthesias and urinary dysfunction

CSF in inflammatory conditionsElectrophysiology:

EMG of S1–S3 musclesSensory conductionsReflex techniques (F waves, H reflex)Spincter EMG including bulbocavernosus reflexMagnetic stimulation

Spinal cord (epiconus- medullary lesions)Rapidly ascending polyneuropathySensorimotor neuropathies with autonomic involvementDepends on the cause

Guigui P, Benoist M, Benoist C, et al (1998) Motor deficit in lumbar spinal stenosis: a

retrospective study of a series of 50 patients J Spinal Disord 11: 283–288

Hoffman HJ, Hendrick EB, Humphreys RB, et al (1976) The tethered spinal cord; its protean

manifestation, diagnosis and surgical correction Childs Brain 2: 145–155

Tyrell PNM, Davies AM, Evans N (1994) Neurological disturbances in ankylosing

spondyli-tis Ann Rheum Dis 53: 714–717

Yates DAH (1981) Spinal stenosis J R Soc Med 74: 334–342

References

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Mononeuropathies are an essential part of clinical neurology The clinical

diagnosis depends on the knowledge of anatomy, the presentation of clinical

syndromes and numerous etiologies

The individual mononeuropathies of the upper extremity, the trunk and the

lower extremities are discussed by the anatomic course of the nerve , anomalies

and their symptoms and signs The most likely causes of damage are discussed

and differential diagnosis is considered Therapeutic aspects and if available

prognosis are mentioned

The references are limited to a few key references Most of our artist‘s

illustrations are devoted to this section The clinical photography should help

the reader to identify the patient’s abnormalities

The concept is an accurate and brief description of the most important

clinical features The trunk nerves which are often neglected are summarized in

a separate subsection

Introduction

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Mononeuropathies: upper extremities

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Genetic testing NCV/EMG Laboratory Imaging Biopsy

Axillary nerve

Fig 1.1 Axillary nerve 2 toid muscle 3 Teres minor muscle

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Anatomy Fibers originate from roots of C5-C6, and travel through the upper trunk and

posterior cord of the plexus

The nerve continues through the axilla (quadrilateral space), with a motorbranch to the teres minor and two further divisions The posterior divisioninnervates the posterior head of the deltoid muscle and gives off the superiorlateral cutaneous nerve The anterior division innervates the lateral and anteriorheads of the deltoid muscle (see Figs 1 and 2)

Weakness in elevation of the upper arm

Signs:

Atrophy, and flattening of the lateral shoulder

Reduction of external rotation and shoulder adduction (teres minor muscle).Deficits of shoulder abduction, flexion, and extension (deltoid muscle).Shoulder abduction is the most clinically relevant deficit, as the other musclesare well compensated

Sensory:

Deficits are variable (and may be absent), involving lateral shoulder and upperarm

Fig 2 Quadrilateral space 1

Teres minor 2 Teres major 3

Medial and lateral-caput

lon-gum of triceps muscle 4 Neck

of humerus 5 Circumflexor

hu-meri posterior artery

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Differential diagnosis Diagnosis

Acute trauma:

Anterior dislocation of the humeral head, fractures of the proximal humerus or

scapula

Prognostic factors are the time between dislocation and reposition, presence of

hematoma, and age

Mainly in association with other nerves, particularly with the suprascapular

nerve, and rarely isolated

Malpositioning:

Sleep, anesthesia

Tumors:

Benign nerve sheath tumors, osteochondroma

Quadrilateral space syndrome:

Neurovascular compression syndrome, with pain, paresthesias (non-anatomic

distribution throughout the limb), and shoulder tenderness

Birth trauma

Infectious:

Measles

Electrophysiology:

Axillary nerve latency CMAP most relevant

Disadvantages: No sensory conduction studies The only stimulation site is

proximal to common entrapment locations Hence, conduction block is hard to

differentiate from axonal lesion in the early stage of nerve injury

EMG: teres minor and all three heads of the deltoid muscle

Imaging:

Traumatic lesions, quadrilateral space syndrome, space occupying structures

X-ray and CT: all traumatic lesions

MRI: teres minor atrophy often seen in quadrilateral space syndrome

Subclavian arteriography: to demonstrate posterior humeral artery occlusion

with shoulder abduction and external rotation

Axillary arteriogram, duplex scan: pseudoaneurysm

± Quadrilateral space syndrome

Musculocutaneous nerve

+

Fig 3. 1 Musculocutaneous nerve 2 Cutaneus antebrachii lateralis nerve 3 Coracobrachi- alis muscle 4 Short head of bi- ceps muscle 5 Long head of biceps muscle 6 Brachialis muscle

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Fig 4 Biceps pathology A

At-rophy of the biceps brachii in a

patient with neuralgic shoulder

amyotrophy Note the absent

relief of the muscle B Biceps

tendon rupture Typical clinical

manifestation with flexion of

the elbow

Fig 5 Nerve metastasis of a

carcinoid tumor in the

muscu-locutaneous nerve A

Intraoper-ative site B The nerve fascicles

are in close connection with

the tumor tissue C Tumor

strands within the nerve (arrow)

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Fibers from C5–7.

Brachial plexus, lateral cord

Innervation: coracobrachialis, biceps, brachialis muscles

Sensory: lateral antebrachial cutaneous nerve – radial aspect of forearm (see

Fig 3)

Wasting of biceps muscle may be noted, difficulties to flex and supinate (rotate

outward) the elbow, reduced sensation along radial border of forearm,

pares-thesia/causalgia (chronic compression or after veinpuncture common), local

forearm pain (chronic compression)

Wasting of biceps muscle Weakness of elbow supination more prominent than

elbow flexion (compensated by brachioradialis and pronator teres muscle)

Hypesthesia along radial border of forearm – sensation becomes normal at

wrist Absent biceps tendon reflex (see Fig 4)

Rarely isolated

Abnormal strenuous exercise (carpet carrier, weight lifting)

Entrapment: strap of a bag carried across the antecubital fossa

Iatrogenic: malpositioning during anesthesia, veinpuncture (lateral

antebrachi-al cutaneous nerve), tight bandage

Neuralgic amyotrophy (isolated and in combination)

Proximal humeral osteochondroma, nerve tumors, false aneurysm

Trauma: anterior dislocation of shoulder (frequently associated with axillary

nerve), traumatic arm extension, missiles

NCV: CMAP and SNAP (compared to unaffected side), EMG, Imaging

C6 radiculopathy

Ruptured biceps tendon

Isolated complete trauma: operative, otherwise conservative

Usually good

Braddom RL, Wolfe C (1977) Musculocutaneous nerve injury after heavy exercise Arch

Phys Med Rehabil 59: 290–293

Juel VC, Kiely JM, Leone KV, et al (2000) Isolated musculocutaneous neuropathy caused by

a proximal humeral exostosis Neurology 54: 494–496

Patel R, Bassini L, Magill R (1991) Compression neuropathy of the lateral antebrachial

cutaneous nerve Orthopedics 14: 173–174

Sander HW, Quinto CM, Elinzano H, et al (1997) Carpet carrier‘s palsy; musculocutaneous

neuropathy Neurology 48: 1731–1732

Young AW, Redmond D, Belandes BV (1990) Isolated lesion of the lateral cutaneous nerve

of the forearm Arch Phys Med Rehabil 71: 25

Symptoms

Signs

Causes

Diagnosis Differential diagnosis

Therapy Prognosis Anatomy

References

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Median nerve

Fig 6.1 Median nerve 2

Inter-osseus anterior nerve 3

Prona-tor teres muscle

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Fig 7.1 Median nerve 2 nar branch 3 Transversal carpal ligament

The-Fig 8 Section at the distal end

of the carpal tunnel 1 Median nerve 2 Ulnar nerve 3 Deep ulnar nerve 4 Flexor retinacu- lum 5 Flexor tendons 6 Flexor pollicis longus 7 Abductor dig- iti minim) muscle

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Fig 9 Transsection of the

me-dian nerve and sural nerve

inter-plantate in a 24 month follow

up A Orators hand prior to

op-eration, B after 24 months the

long flexors of the thumb and

particularily the index finger

show increased mobility

Fig 10 Acute carpal tunnel

syndrome. A Local painful

swelling of the left volar wrist,

sensory loss in median nerve

distribution B After

confirma-tion with ultrasound the median

nerve was released C Residual

deficits were a sensory loss of

the volar sides of the fingers

(marked with a ball pen)

Fig 11 Trophic changes after a

median nerve transsection and

nerve implantation A Shows

“orators hand”, with thenar

at-rophy B Shows glossy skin over

index finger, and trophic

chang-es of the nailbed

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Fig 12 Complete transsection

of the median nerve at the

up-per arm A Handposition trying

to make a fist Inability to flex index finger and thumb Ulcer due to sensory loss at the tip of

the index finger B Sensory loss

is accentuated at the tip of the fingers, but also palm is in-

volved C Dorsal view of the

hand, delineating the sensory impairment

Fig 13 Carpal tunnel

syn-drome Typical atrophy of the thenar eminence

Fig 14 Neuropathic pain This

patient suffered from a plete median nerve transsection

com-at the upper arm 2 years lcom-ater his hand felt uncomfortably and painfully cold Touch could elicit neuropathic pain The patient wears a glove to avoid these sensations

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Fibers for the median nerve are found in the lateral and medial cord of thebrachial plexus, C5–T1 The nerve runs along the lateral wall of the axilla,adjacent to the axillary artery, continuing through the upper arm close to thebrachial artery, and then medial to the biceps tendon In the forearm, it is foundbetween the superficial and deep heads of the pronator teres muscle, which itsupplies The nerve sends branches to the flexor carpi radialis, palmaris longus,and flexor digitorum superficialis muscles, then divides into a pure motorbranch, the anterior interosseus nerve, innervating the flexor pollicis longus,pronator quadratus, and the flexor digitorum profundus I and II The mainbranch enters the hand through the carpal tunnel and innervates the abductorpollicis brevis, opponens pollicis, the lateral half of the flexor pollicis brevis,and the first and second lumbrical muscles There are also sensory palmardigital branches (see Figs 7 and 8).

Martin Gruber anastomosis:

Nerve fibers cross from the median nerve to the ulnar nerve in the forearm.Variations include:

a) Median fibers crossing to the ulnar, then travel to the hand and supplymuscles which are normally supplied by the median nerve

b) Similar to a), but the motor fibers supply both median and ulnar musclesc) Ulnar nerve motor fibers enter the median nerve from the brachial plexus,travel to the forearm, then travel to the hand and innervate muscles supplied

by the ulnar nerve

Rare: ulnar-median anastomosis Richie Cannieu anastomosis Rare: sensory crossover Recurrent motor branch of median nerve Palmar cutaneous branch

Lesions in shoulder, axilla, upper arm:

Weakness in pronation (compensated partially by the brachioradialis muscle),wrist flexion (associated with ulnar deviation), and loss of hand function (weakabduction and opposition of thumb, inability to flex distal interphalangealjoints of dig I–III, and of proximal joints of dig I and II) (see Fig 12)

Elbow:

Pronator teres syndrome:

Pain over the pronator teres muscle, weakness of flexor pollicis muscle, vation of pronation, and sensory changes over the thenar eminence

preser-Anterior interosseus syndrome:

Synonymous with Kiloh and Nevin syndrome Pain in the forearm, but normalsensation Pinch sign: inability to form a circle with fingers I and II

Wrist: carpal tunnel syndrome (CTS) (see Figs 9 through 11, 13 and 14):

Nocturnal paresthesias in the hand, may radiate up to shoulder

Paresthesias during daytime, particularly during the use of the hand with forcedflexion or extension at the wrist

Local pain at the wrist.

Sensory symptoms of the first three digits and the radial half of the fourth digit

Most commonly, hypesthesia is restricted to the volar tip of the second and third

finger

Weakness of thumb abduction and opposition

Sensory loss may result in clumsiness

Motor sign: Thenar atrophy

Clinical testing:

Tinel’s sign – about 70% sensitivity

Phalen’s sign – about 80% sensitivity

Tumors & masses

Pronator teres syndrome:

Anterior interosseus neuropathy

Chronic compression

Direct injury

Excessive muscular exercise

Midshaft radius fractures

CTS

Space reduction in carpal tunnel:

Exostoses

WristProximal forearm

GangliaGoutOsteophytesRheumatoid arthritis (RA)Tendons

VascularIncreased susceptibility:

DiabetesHereditary neuropathiesLeprosy

Uremic neuropathyOthers:

AcromegalyAmyloidosisA-V shuntFamilial dispositionHypo- and hyperthyroidismInfections

IdiopathicMucopolysacharidosisPregnancy, lactationWork relatedAcute CTS (rare)HematomaInfection

RA exacerbationWrist fracture and dislocationDigital nerve entrapment:

InflammationTraumaTumor

Electrophysiology (NCV, EMG)Imaging

Laboratory

Radicular lesions C6 and C7Thoracic outlet syndromeThalamic infarcts

Depends on the etiology and electrophysiology

CTS: forearm splint at nighttime, ultrasound at wrist

In acute CTS, CTS with motor impairment, or persistent entrapment despiteconservative therapy: operative split of carpi transversum, either via endoscop-

ic or open technique Prognosis for both techniques is good (85% success)

Atroshi R, Johnsson R, Ornstein R (1997) Endoscopic carpal tunnel release: a prospective

assessment of 255 consecutive cases J Hand Surg (Br) 22: 42–47

Cseuz KA, Thomas JE, Lambert EH, et al (1966) Long term results of operation for carpal

tunnel syndrome Mayo Clin Proc 41: 232–241

Harness D, Sekeles E (1971) The double anastomotic innervation of the thenar muscles.

J Anat 109: 461–466

Hopf HC (1990) Forearm ulnar to median anastomosis of sensory axons Muscle Nerve 13:

654–656

Padua L, Paciello N, Aprile I, et al (2000) Damage to peripheral nerves following

radio-therapy at the wrist J Neurol 247: 313–314

Rosenbaum RB, Ochoa JL (1993) Carpal Tunnel Syndrome and other disorders of the

median nerve Butterworth Heinemann, Boston

Todnem K, Lundemo G (2000) Median nerve recovery in carpal tunnel syndrome Muscle

Nerve 23: 1555–1560

Zifko UA, Worseg AP (1999) Das Karpaltunnelsyndrom Diagnose und Therapie Springer,

Wien New York

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Ulnar nerve

exploration

Fig 15. 1 Ulnar nerve 2 Dorsal

cutaneus branch 3 Deep motor

branch

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Fig 16 Medial epicondyle and

cubital tunnel 1 Right ulnar nerve 2 Medial epicondyle 3 Aponeurosis 4 Flexor carpi ul- naris

Fig 17.1 Ulnar nerve 2 Deep terminal branch 3 Thenar mus- cles

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