Surgical Management of Brachial Plexus Injuries

SURGICAL MANAGEMENT OF BRACHIAL PLEXUS INJURIES

Surgical options

1) neurolysis

2) restoration of neural input

3) Replacing non-functional muscles

4) Treatment of secondary deformities

Bony stabilization
Arthodesis
Osteotomies
Tendon transfers

Approach

· Incision – posterior border of SCM, then 1 finger below clavicle and then along the deltopectoral groove

· Subplastymal flaps

· External jugular vein ligated

· omohyoid muscle and the transverse cervical vessels are identified and retracted or divided

· Open clavicular osteotomies have the tendency to create malunions and, more often, nonunions and therefore, they should be avoided.

· if difficult to identify all roots, dissect the infraclavicular portion by detaching Pectoralis Minor and as much of Pectoralis Major as necessary

· phrenic nerve is identified in its usual anatomic position in the anterior border of the anterior scalene muscle, and it is traced superiorly to its C4 and C5 origins.

Identification

· Intraoperative somatosensory evoked potentials are used by some centers.

· Biopsies can be obtained for:

1. carbonic anhydrase histochemistry or cholinesterase staining.

o carbonic anhydrase can differentiate between motor and sensory fascicles of peripheral nerves.

o Motor nerves stain more densely for Acetylcholinesterase

o prolonged incubation time (more than 24 hours) needed to visualize the acetylcholinesterase in motor fibers makes this staining technique nonpractical because it means that the patient is subjected to two operative procedures within a 2-day period.

2. frozen biopsies of a root can determine the presence of dorsal root ganglion cells, which indicate a nonreparable lesion.

· Intraoperative nerve action potentials can also assist in distinguishing ruptured from avulsed roots and are used by many authors.

Nerve Reconstruction

Timing

· 3-6 months

Methods

· Establish root avulsion vs rupture

1. in avulsion, intraplexus donor will not be available

2. direct spinal cord implantation has been reported in 1 child using sural nerve graft and fibrin glue containing acidic FGF.

· Mangement of neuroma in continuity

o Intraoperative nerve stimulation useful

o In most cases where there is significant clinical weakness, resection of neuroma to healthy axons is indicated with intercalated nerve grafting

· Microneurolysis performed if there is significant fibrosis

o longitudinal epineurotomies

o Bulging of the entrapped fascicles strongly indicates that microneurolysis is effective.

· Nerve grafts often required

o Autograft Donors

Sural nerve – 35cm each leg
Medial cutaneous nerve of forearm
Ulnar nerve if avulsion of C8, T1

· Need to strip off dorsal sensory branch to reduce thickness of the nerve for better viability

Great auricular nerve

o Best recovery with musculocutaneous nerve, suprascapular nerve

§ 75% of free nerve grafts for elbow reinnervation expected to have M3 function and above; strength and function of the best of these grafts are better than anything that can be produced by tendon transfer

o Intermediate with radial nerve and poor with ulnar nerve

o Vascularised donors

§ Free vascularised ulnar nerve most commonly used

§ Not shown to be better than grafts

· Nerve source

o Priorites

§ Shoulder external rotation

· Infraspinatus – suprascapular nerve

· Teres minor – axillary nerve

§ Shoulder abduction

· middle part of deltoid – suprascapular nerve

· supraspinatus – axillary nerve

§ Elbow flexion

· Biceps - musculocutaneous

· Brachialis – musculocutaneous

o Intraplexus motor donors, such as the proximal stumps of ruptured roots, yield, in general, better results because they carry a higher number of axons.

§ If C5/6 avulsed, sacrifice C7 for C5/6 and use extraplexal donor for C7 targets

o Extraplexus donors (nerve transfer)

§ If C5/6/7 avulsed – extraplexal donors include such as intercostal nerves, accessory nerve, and the contralateral C7 root.

§ Suprascapular

· Distal spinal accessory

· Intercostal

· Medial Pectoral nerve

· partial hypoglossal

§ Musculocutaneous

· Intercostal – usually need 3 branches (1300 axons each branch vs 6000 in MCN)

· Distal part of Spinal accessory nerve

· Medial Pectoral nerve

· 1-2 fascicles of ulnar nerve (Oberlin transfer) – advantage of anastamosing to the distal motor branches of biceps and or brachioradialis. Cant use if C8,T1 damaged

· Distal spinal accessory – downgrades distal trapezius

§ Axillary

· Intercostal

· Nerve to long head of triceps (Erbs palsy)

§ Median/Radial nerve

· Contralateral C7

o Results

§ reinnervation of the suprascapular nerve (92%) demonstrates significantly better outcomes for >=M3 shoulder abduction than the axillary nerve

§ % of supraspinatus muscle function recovery greater than M3 with:

· accessory nerve – 84%

o often require nerve graft

· ipsilateral intercostal nerves – 52%

o usually 3rd to 5th nerve, try to spare 4th in women

o highest content of motor nerves just distal to lateral cutaneous branch

o Studies have demonstrated that intercostal nerves lose up to 10% of motor axons with each 10 cm of distal progression from the midaxillary line to the sternum

o ensure that patient has not had previous rib fractures, chest tubes

· cervical plexus motor donors – 45%

o up to 4 rami available

o unpredictable results

· phrenic nerve – 40%

o pulmonary capacity decreases 1 year after surgery but returns to normal at 2 years

· contralateral C7 – 51% (require long nerve grafts)

· ulnar nerve – 10% cross sectional area

Oberlin transfer for elbow flexion

Replacing Non Functional Muscles

Timing

· Based on either time elapsed since surgery or the direct knowledge of the state of the nerves

· Persistence of the deformity leads to flattening of the humeral head and glenoid over time. Humeral head subluxation and glenohumeral dislocation may also be observed. These alterations in normal joint anatomy may limit potential motion gains from surgery. Therefore, corrective procedures are best undertaken before permanent bony deformity at 3 to 4 years of age in obstetrical brachial plexus palsy.

Principles

Joint mobility
Adequate soft tissue cover
Absence of oedema
Donor muscle must be of adequate strength and amplitude of excursion
Patient cooperation and motivation

Shoulder reconstruction

Trapezius transfer for shoulder abduction

o transfer of the clavicular and acromial insertion of the trapezius with or without fascia lata to the deltoid insertion on the humerus to enhance abduction and reverse subluxation.

L’Episcopo procedure for external rotation

o Transpose latissumus dorsi and teres major posterolaterally to rotator cuff to improve external rotation

o Two incisions, approximately 4 cm in length, are outlined in the anterior and posterior axillary folds, respectively. Through the anterior incision, the insertion of the pectoralis major is identified and Z-lengthened.

o insertions of the latissimus dorsi and teres major tendons are tagged with 0 nonabsorbable braided polyester (Ethibond) suture and released. Passive external rotation is then assessed. Additional anterior structures (subscapularis, capsule) may be released if necessary to achieve 60° of passive external rotation

o posterior portion of the deltoid is then retracted. With the brachium held in external rotation, the tendons are transferred and sutured as high as possible on the insertion of the rotator cuff in the region of the greater tuberosity.

o Does not add abduction, and trapezius transfer should be added if this isn’t present preoperatively.

Pectoralis transfer for shoulder flexion

o transfer of the sternocostal part of the pectoralis major to the anterior deltoid for anterior flexion

Glenohumeral Arthrodesis

o As a salvage procedure

o need serratus anterior and trapezius intact to have some control of scapulothoracic complex

o if not, better to leave it flail

Restoration of elbow flexion

· Must have a passive range of greater than 90 degrees.

· Best results with Lat Dorsi>Triceps>Pec Major=flexorplasty

Steindler flexorplasty

§ Devised by Arthur Steindler 1918

§ EMG to ensure FDS/FCR function

§ The flexor-pronator muscles (PT, FCR, FDS, PL, FCU) arising from the medial epicondyle are transposed to a more proximal point (4-6cm) on the humerus

§ Original description was insertion to the medial intermuscular septum

§ Modified by Green to bony fixation to the anterior aspect of humerus

§ Attachment to bone is stronger

§ More lateral attachment prevents pronation during flexion

§ Need normal or near normal power prior to transfer

§ dramatic increase in the overall

§ results of the flexorplasty can be achieved by performing additional tendon transfers for wrist and finger extension.

Pectoralis muscle transfer

· Devised by Clark 1945

· Uses sternocostal portion

· The shoulder must be strong or fused to prevent dissipation of muscle power.

· Inserted into the biceps tendon

· Use rectus sheath attached to it for suturing

· Not recommended in women

· may have better functional results than a flexorplasty, but the ability to hold objects against the body may be lost (thoracohumeral grasp)

· Pectoralis minor also described - has been used to supplement a flexorplasty when initial elbow flexion is less than M2.

Latissimus transfer

· Can be used for restoration of elbow flexion and extension

· First proposed by Schottstaedt, Larsen, and Bost in1955

· Often not available because innervation C5 C6 C7 same as those being augmented

Triceps transfer

· Controversial as some consider loss of active elbow extension is disabling

· 3 serious negative factors

1. precludes working with the arm in front of the body or at the horizontal position or using the arm as a stabilizer

2. smooth action of flexion is aided by the presence of an active agonist

3. possibility of a flexion contracture secondary to an unopposed action

Sternocleidomastoid transfer

· no longer used because of the resultant neck deformity and the need for grotesque facial and neck manipulations to achieve flexion.

· Disadvantages

1. unsightly web in the neck

2. occasionally unsightly manipulations of the neck to activate the muscle

Free Muscle Transfer

· For restoration of elbow flexion and reanimation of the hand

· Terzis leaves banked nerves from ipsilateral motor donors, such as the eleventh cranial nerve, or intercostal nerves or cross-chest nerve grafts from the contralateral anterior or posterior divisions of the C7 root.

· Elbow Flexion

o Lat Dorsi / rectus femoris / gracilis

· Finger Flexion

o Gracilis