Brachial plexus surgery: A new technique in panbrachial plexus injury

In total brachial plexus injury when ipsilateral spinal accessory nerve is also traumatized we offer the use of contralateral SAN as an additional option in the reinnervation of suprascapular nerve.

Technique-
Through a transverse incision over the spine of scapula, the distal part of suprascapular nerve (SSN) is dissected up to the suprascapular notch. SSN is divided at its origin from the upper trunk and delivered through the scapular incision. Through another incision over the contralateral scapular spine, the spinal accessory nerve (SAN) is dissected free, while preserving its branches to the upper and middle parts of trapezius muscle. Distal vertical course of SAN is dissected along the medial border of scapula and the nerve is divided and delivered to the surface. A sural nerve graft is interposed between the ends of SAN and SSN and nerve coaptations are carried out with 10-0 nylon suture under an operating microscope.

Discussion
In panbrachial plexus injury root avulsions are common and at times associated with injury to the donor nerves (e.g phrenic and SAN). Histomorphometric studies have suggested an adequacy of myelinated axons in the distal part of spinal accessory nerve. Based on this we have used the contralateral SAN lengthened with a graft to reinnervate the injured SSN. We consider the use of contralateral SAN is a viable option in restoration of shoulder function.

Secondary surgery for late obstetric brachial plexus palsy

Introduction
The incidence of obstetric brachial plexus palsy (OBPP) ranges globally from 0.5 to 2 per 1000 births with the higher numbers in under developed countries. A majority of them progress to complete recovery, other may improve slowly but incompletely. The rate of complete, spontaneous recovery varies in the literature from 30 % to 95 %. Factors associated with OBPP include large birth weight, breech delivery and shoulder dystocia.

Microsurgical reconstruction of OBPP is a relatively new area of work in the peripheral nerve surgery. There is a great dispute amongst the clinicians regarding the surgical indications and timing of surgery. Many still advise the parents to adhere with the physiotherapy programme even for the cases not showing recovery after a reasonable period of time. This ultimately leaves many children with deformities in the shoulder, elbow and forearm. Such children are unable to perform self care activities, such as grooming, feeding and washing themselves, because of limited active external rotation, abduction, elbow flexion, and pronation contracture in forearm. These children, though, will improve significantly with the muscle release and tendon transfer surgery, but results will always be inferior to a primary nerve surgery performed in the early infantile age.

Subscapularis release
In this lateral decubitus position, a longitudinal incision is made along the lateral border of the scapula and dissection is carried down to the latissimus dorsi muscle, the fibres of which cover the lateral aspect of scapula. This muscle is retracted inferiorly and the inferior angle of scapula is stabilized with a strong suture or towel clips.

The subscapularis muscle is elevated from the anterior surface of the scapula with the use of electrocautery or a periosteal elevator. Dissection is performed in a subperiosteal fashion, progressing from the inferior angle upwards. An external rotatory force on the humerus is applied through out

the release to confirm adequate release. Care is taken to avoid injury to the subscapularis vessels and nerve running from anteromedial to the glenoid neck and anterior to the subscapularis muscle as well as injury to suprascapular vessels and nerve running from anterior to posterior over the scapular notch. The wound is closed over a suction drain and arm splinted to abduction and external rotation. This splint is maintained full time for three months, removing it only to bath and for gentle range of motion exercises, which are begun at 6 weeks.

Transfer of the conjoint tendon of latissimus dorsi and teres major to the rotator cuff

The patient is placed in the lateral decubitus position. An incision is made in the axilla in a transverse direction. Pectoralis major muscle, if contracted, is released from its insertion. If the pectoralis muscle is not contracted, a single transverse incision is made in the posterior axilla. Subscapularis muscle is released if indicated. The tendons of latissimus dorsi and teres major are released with protection of radial nerve and the contents of the quadrilateral space. The interval between the posteroinferior margin of deltoid muscle and the rotator cuff is developed and the arm is maximally abducted and externally rotated. The released tendons of the latissimus dosri and the teres major are next transferred posterior to the long head of the triceps muscle and sutured as superiorly as possible to the rotator cuff.Two longitudinal incisions are made in the cuff, and the tendons are pulled through these incisions and sutured to themselves, thereby converting the latissimus dorsi and teres major muscles in to external rotators of the shoulder.  A shoulder spica is fitted with the shoulder in 60 to 90 degrees of abduction and external rotation. This splint is continued full time for three months and only at night for an additional three months.


Lateral shifting of clavicular origin of pectoralis major and transfer of teres major muscle to the infraspinatus muscle

Clavicular orgin of pectoralalis major is erased from the clavicle and after mobilization sutured to the periosteum on the later third of the clavicle. Through a posterior incision, teres major muscle is divided at its insertion, separated from the latissimus dorsi muscle and sutured superiorly to the infraspinatus muscle. Immobilization is maintained as per the previous techniques.

Derotation Osteotomy of the humerus
Through an anterior incision in the deltopectoral groove with its extension into upper arm, proximal humerus is exposed between the anterior border of the deltoid and the biceps. The osteotomy is performed between the insertions of the pectoralis major and the deltoid. The elbow is maintained in a flexed position while the distal fragment of the humerus is rotated laterally and kept adjacent to the body until the hand could be brought to the mouth. Osteotomy site is fixed with a 4 or 5 hole plate with screws.No drains were kept. A plaster spica is applied with the shoulder in 90 degrees of abduction and full external rotation, the elbow in 90 degrees of flexion and the forearm in full supination. The cast is maintained for 6 weeks.

Recent advances in brachial plexus surgery

Traditionally, spinal accessory to suprascapular nerve transfers have been performed by anterior approaches. However transection of spinal accessory nerve at proximal level leads to denervation of upper trapezius, which plays an important role in shoulder function. Distal transection spares the important branches to trapezius and preserves its function of shoulder stabilization and elevation.

Dorsal/ Posterior approach in suprascapular reinnervation
Dorsal or posterior approach in spinal accessory nerve in to the suprascapular nerve is expected to lack some of the drawbacks of the anterior transfers. This technique neurotizes suprascapular nerve by distal spinal accessory nerve through a transverse incision over the scapular spine.Hence function of most of trapezius is preserved.The distal transfer is close to the target muscles and identifies, if any, a distal injury to the suprascapular nerve (e.g, near the suprascapular notch). In addition the dissection is in a safe and relatively avascular zone. This technique is gaining popularity as a standard technique in spinal accessory nerve to suprascapular nerve transfer.

New nerve transfers
Transfer of a single fascicle of ulnar nerve to the motor branch of biceps  and a fascicle of median nerve to the brachialis motor branch  have produced the most promising results in elbow flexion in partial plexus injuries. This technique is simple and requires no special re-education of the muscle. Sparing of 1 or 2 fascicle from the ulnar and median nerves does not result in any subjective deficit of hand function.

Axillary nerve neurotization through the anterior approach not only requires nerve grafts but also results in dilution of nerve fibers reaching the deltoid muscle. A posterior approach allows the transfer of long head of triceps branch to the anterior branch of axillary nerve.

Serratus anterior muscle has been reinnervated by transfer of either medial or lateral branch of the thoraco- dorsal nerve to the long thoracic nerve with promising results.

In the management of isolated lower trunk injury brachialis muscle branch of musculocutoneous nerve is transferred to the posterior fascicular group of median nerve. Posterior fascicular group is mainly composed of anterior interosseous nerve innervating the finger flexors. To restore finger flexion, motor branch to the brachioradialis muscle has been transferred to the anterior interosseous nerve in the management of lower plexus lesions.

Contralateral C7 nerve transfer by prespinal route
To reduce the distance to the target nerves, grafts connected with the contralateral nerve root, have been placed underneath the anterior scalene and longus colli muscles, and then passed through the retro-esophageal space to neurotize the recipient nerve.

Nerve allografts
The use of allografts has been practiced by Mackinnon et al in the humans and the groups involved in hand transplanation.  Nerve allografts act as a temporary scaffold across which axons regenerate.

Fibrin glue in nerve coaptation
Nerve repairs performed with fibrin sealants produce less inflammatory response and fibrosis and result in better axonal regeneration and better fiber alignment than the nerve repairs performed with microsutures alone.  In addition, the fibrin glue repairs are faster and easier to perform.

Brachial plexus surgery: Its past, present and future

Background-Traumatic brachial plexus injury is a devastating condition resulting   mainly from motor cycle accidents and primarily affecting the young adults. In the past there was a pessimistic attitude in the management of these injuries. However in last two decades with the introduction of microsurgical techniques and advancements in imaging modalities, these injuries are being explored and repaired early with satisfactory to good functional out comes.

Methods-Neurolysis, nerve repair, nerve grafting, nerve transfer, pedicle muscle transfer and functioning free-muscle transfer are the main surgical procedures in the management of brachial plexus injury. An immediate intervention is considered in stab or iatrogenic injuries. All other common high velocity traction injuries are initially observed for a spontaneous recovery. If there are no signs of recovery by three months, surgery is indicated, as further delay will affect the ultimate results. In global brachial plexus palsy with all root avulsions, intervention is even earlier, as chances of spontaneous recovery are practically nil. Nerve allografts with new immunosuppressant (FK-506) are being used where there is paucity of autografts. Direct replantation of avulsed spinal roots into the spinal cord is a new area of research in brachial plexus reconstruction. Use of fibrin glue in nerve coaptation has considerably reduced the operating time

Results– Good results are expected with early intervention in upper plexal lesions. Results are favorable with short nerve grafts, distal nerve transfers, and intraplexal neurotization. The aim in global brachial plexus palsy is to restore the elbow flexion and provide a stable shoulder. Restoration of a fully functional and sensate hand is still far from being a reality.

Conclusion– The management of brachial plexus injury remains a challenging problem. Functional results have considerably improved in the past two decades with the incorporation of microsurgical techniques in nerve surgery, and advancements in anesthesia. Following microsurgical reconstruction many of these patients are expected to return to their original work and amputation is no longer considered a treatment option. However, despite advances in understanding of pathophysiology of nerve injuries and advent of microsurgical techniques, the outcomes of repair have still not reached its zenith.

Brachial plexus injuries: An overview

A brachial plexus injury results from the injury to the network of the nerves and manifests as impairment of motor and sensory functions of the involved upper limb. Brachial plexus injury is usually sustained in high speed motor bike accidents. These injuries occur in approximately 4.2% of motor cycle accidents.1 Other less common modes of injury include automobile accidents, falls, sports injury, bicycle and pedestrian accidents, stab and gunshot wounds, inflammation ( Brachial neuritis or Parsonage Turner syndrome) and compression by tumors. The magnitude of injury may vary in severity from a mild stretch to the nerve root tearing away from the spinal cord.

Brachial plexus injury leads to weakness or a partial or complete paralysis of the involved upper limb depending on the nerves injured. There may be an impairment or a total loss of sensation. Few patients experience burning or crushing kind of pain in the affected extremity.

Anatomy of brachial plexus
The brachial plexus is a network of nerves that originate from the spinal cord (5th to  8th  cervical (C5–C8), and 1st  thoracic (T1) spinal nerves)  and  control the movement and sensation in the upper limb. The brachial plexus is formed by a union of anterior rami of the lower four cervical (C5 through C8) and the first thoracic (T1) spinal nerves between the anterior and middle scalene muscles. Some nerve fibers to the plexus may originate from the fourth cervical (C4, prefixed) or from the second thoracic (T2, post fixed) nerves. The sympathetic ganglion is in close relation to the T1 root. Three nerves receive contributions at the root levels; dorsal scapular nerve (C5,C6) supplying the levator scapulae and the rhomboid muscles, long thoracic nerve( C5,C6,C7) which supplies the serratus anterior muscle, and phrenic nerve (C3,C4,C5).

The anterior rami of C5 and C6 join to form the upper trunk. The suprascapular nerve arises from the superolateral aspect of the upper trunk. The C7 ramus continues   as the middle trunk, and C8 and T1 combine to form the lower trunk. Each trunk divides retroclavicularly into anterior and posterior divisions. The anterior divisions of the upper and middle trunks unite to form the lateral cord. The anterior division of the lower trunk continues as the medial cord. The posterior divisions of all trunks join to form the posterior cord. The lateral pectoral nerve arises from the lateral cord. The medial cord gives off medial pectoral nerve, medial cutaneous nerve of arm and medial cutaneous nerve of forearm. Three nerves take origin from the posterior cord; the upper subscapular nerve, lower subscapular nerve, and the thoracodorsal nerve.

The cords eventually divide into terminal branches. The lateral cord divides in to the musculocutaneous nerve and lateral root of the median nerve. The medial cord gives off the medial root of the median nerve and continues as the ulnar nerve. The median nerve is formed by the union of medial and lateral cord contributions. The posterior cord terminates into the axillary and radial nerves.

Types of BPI

As per severity

1. Neuropraxia – It is caused   by stretching of nerves and usually recovers spontaneously.

2. Rupture – The nerve is torn but maintains its attachment to the spinal cord.

3. Avulsion – The nerve is torn away from its attachment at the spinal cord. It is the severest form of injury and presents as partial drooping of upper eyelid, if roots involved are C8 and T1 (Horner’s syndrome).

As per involvement of nerves

1. Upper brachial plexus injury – It involves the C5, C6 spinal nerves and presents with a weak shoulder and elbow. Functions of hand remain intact. In obstetric group it is called Erb’s palsy. Involvement of C7 nerve is termed as an extended upper plexus injury.

2. Total brachial plexus lesion – It affects almost all the nerves of the plexus and presents with a flail limb without sensations.

3. Lower brachial plexus injury– This type of injury involves the infraclavicular part of plexus. Shoulder functions are intact but elbow and hand are paralysed.

Surgery for brachial plexus injury: Clinical examination

A patient with brachial plexus injury is likely to have sustained other concomitant injuries; head injury, fractures in the cervical spine, clavicle, scapula, and extremities, chest and abdominal trauma and vascular injuries. The neurological examination should determine the specific motor and sensory deficits. The British Medical Research Council grading system is used to measure the motor strength of each muscle.

A detailed neurological examination helps in identifying the site and severity of the injury and dictates the treatment algorithm. In partial injuries some of the functions in limb are intact. In upper brachial plexus palsy (C5, C6) shoulder and elbow functions are poor, however hand functions are preserved. Extended upper plexus palsy (C5,6,7) has additional weakness wrist and finger extension. Lower brachial plexus palsy (C8-T1) presents with poor hand functions with normal shoulder and elbow functions.

In total palsy entire limb is flail and insensate, superficial sensations being present only in the inner aspect of arm which receives innervation from the T2 dermatome. The limb hangs by the side of the body with arm and forearm being internally rotated. A positive Horner’s sign (Fig 1) indicates C8, T1 nerve root injuries with involvement of cervical sympathetics. Examination of individual muscle helps in indentifying the site of injury and forms a baseline to assess recovery. The neurological examination should determine the specific motor and sensory deficits. The British Medical Research Council (BMRC) grading system is used to measure the motor and sensory functions of the extremity (Table 1).

Table 1- Assessment of motor power by the British Medical Research Council grading system

Muscle Grade Description
5 Full range of movements against gravity with full resistance
4 Full range of movements against gravity with some resistance
3 Full range of movements against gravity
2 Full range of movements with gravity eliminated
1 Flicker of contraction
0 No contraction

Sensory examination is performed using two-point discrimination or Semmes Weinstein monofilament testing (Table 2).
Table 2- Assessment of sensory functions by the British Medical Research Council grading system

Grading Description
S0 No sensation
S1 Recovery of deep cutaneous pain sensibility
S2 Recovery of superificial cutaneous pain sensibility
S2+ Same as S2, only with over response
S3 Pain and touch sensibility with a disappearance of over response. Two-point discrimination > 15 mm
S3+ Same as S3, only localization of the stimulus is good. Two-point discrimination 7 to 15 mm
S4 Recovery of complete sensation. Two-point discrimination 2 to 6 mm

An examination of individual muscles helps in indentifying the site of injury and forms a baseline to assess recovery (Table 3).
Table 3 – Brachial plexus examination sheet

General Clinical examination
Sign Implications
Horner Sign Sympathetic ganglion injury (T1)

Diaphragmatic palsy

Phrenic nerve injury (C3-C5)

Tinel sign in neck

Root rupture (Proximal root stump may be present)
Deafferentation pain Root avulsion
Winged scapula Long thoracic nerve injury(C5-C7)
Muscle Root value Remarks (Bulk & Power)
Trapezius C3,C4, Spinal accessory nerve  
Levator scapulae C3,C4,C5  
Rhomboids C4,C5  
Supraspinatus C5,C6  
Infraspinatus C5,C6  
Serratus anterior C5,C6,C7  
Teres major C5,C6  
Subscapularis C5,C6,C7  
Pectoralis major clavicle C5,C6,C7  
Pectoralis major sternocostal C6,C7,C8 T1  
Latissimus dorsi C6,C7,C8  
Biceps and brachialis C5,C6  
Deltoid C5,C6  
Teres minor C5,C6  
Pronator quadratus C7,C8,T1  
Pronator teres C6,C7  
Flexor carpi radialis C6,C7  
Flexor digitorum profundus II, III C7,C8,T1  
Flexor digitorum superficialis C7,C8,T1  
Flexor pollicis longus C7,C8,T1  
Abductor pollicis brevis C6,C7,C8,T1  
Opponens pollicis C8,T1  
Lumbricals C8,T1  
Triceps C6,C7,C8  
Supinator C5,C6  
Brachioradialis C5,C6  
Extensor carpi radialis longus C6,C7  
Extensor carpi radialis brevis C6,C7,C8  
Extensor carpi ulnaris C7,C8  
Extensor digitorum communis C7,C8  
Extensor digiti minimi C7,C8  
Extensor indicis C7,C8  
Extensor pollicis longus C7,C8  
Abductor pollicis longus C6,C7  
Flexor carpi ulnaris C7,C8,T1  
Abductor digiti minimi C8,T1  
Flexor digitorum prof. IV, V C7,C8,T1  
Abductor pollicis C8,T1  
Opponens digiti C8,T1  
Interossei C8,T1  

 

 

Surgery for brachial plexus injury: Techniques

Timing of Repair
The commonly seen closed injuries are initially managed conservatively. Some of them are neuropraxic injuries and recover in few weeks time. Other injuries should be observed up to 10 to 12 weeks for spontaneous recovery. During this period passive range of joints is maintained. After one month of injury an electromyography and CT myelography / MR myelography is performed. Patients with clinical (flail and anaesthetic limb, Horner’s sign, severe deafferentation pain) and radiological evidence of root avulsions( pseudomeningoceles) can be operated at this time. Other patients should be followed for another 6 to 8 weeks for neurological recovery. If there is no recovery, surgery should not be delayed further as results of surgery deteriorate with passage of time. If partial recovery has occurred, exploration and reconstruction of the nerves that are not recovering is indicated. Management of missile injury of the brachial plexus differs considerably from the traction injuries. The tissues are crushed and burnt from a direct contact with the missile and stretched via temporary cavitation. Wounds are heavily contaminated with virulent organisms.These injuries are better treated as delayed repair if there is little or no recovery.

Surgical techniques: Exposure of brachial plexus
Exploration of plexus is done under general anesthesia through a reverse C shaped incision with its horizontal limb about 1 cm above and parallel to the clavicle and the vertical extension along the posterior border of the sternocleidomastoid muscle. The supraclavicular pad of fat is reflected downwards and laterally from the posterior border of sternocleidomastoid muscle. The inferior belly of omohyoid muscle is divided and plexal elements are identified in the space between the anterior and middle scalene muscles. Their absence suggested root avulsions.

The suprascapular nerve is located along the lateral aspect of the upper trunk. Often its proximal end is involved in the upper trunk neuroma. In severe traction injuries suprascapular nerve is retracted distally and might be located in the retro- or infraclavicular region. The spinal accessory nerve is located, once the deep fascia is incised along the anterior border of the trapezius muscle. The phrenic nerve is located on the anterior surface of scalenus anterior muscle and identified by its vertical course and contractions of diaphragm on electrical stimulation.  It is dissected distally and then divided and moved laterally for transfer. Infraclavicular plexus is explored through an incision in the deltopecteral groove with its distal extension in the inner aspect of the arm. Exposure of the cords and their terminal branches usually need the division of pectoralis major and minor muscles.

Surgical techniques: Nerve related procedures
1. Direct nerve repair – A direct nerve repair without nerve grafts is possible in only sharply transected injuries (stab and iatrogenic injuries) provided the proximal and distal ends can be approximated without the tension. In more common traction injuries nerve ends are retracted apart and a direct coaptation is not feasible.

2. Nerve grafting – Nerve grafting is the predominant technique employed in brachial plexus repair. Nerve grafts are required in traction injuries to bridge the nerve defects once the neuromas are resected. The commonly used donor nerves are the sural nerve, medial cutaneous nerve of the forearm, lateral cutaneous nerve of the forearm and ipsilateral ulnar nerve as a pedicled vascularized nerve graft in lower root avulsions.

The nerve graft should be 20% longer than the length of the nerve defect.  Vascuarized nerve grafts may be more suitable in a scarred bed and at reconstructing large nerve defects.  In global brachial plexus with C8 and T1 root avulsions, pedicled vascularized ulnar nerve has been used for a contralateral C7 root transfer to the median nerve.

3. Nerve transfers– Nerve transfer or nerve bypass procedure involves transfer of a functional but less important nerve to the distal injured nerve usually within a period of 6 to 9 months after the injury. Nerve transfers are performed for repair of severe brachial plexus injury in which the proximal spinal nerve roots have been avulsed from the spinal cord.  The use of nerve transfers has been a major advance in the field of brachial plexus reconstruction with many different donor nerves being used to restore the desired function.

In partial brachial plexus injuries, both extraplexal and intraplexal nerve transfers, result in good functional outcomes. An important aspect in nerve transfer is to reinnervate the target muscle close to its motor end plates. This reduces the denervation period and functional gains are superior when compared to proximal nerve transfer.

In extraplexal neurotization a non brachial plexus component nerve is transferred to an injured nerve. One of the most commonly performed extraplexal nerve transfer is between the spinal accessory nerve  and the suprascapular nerve. This restores useful degree of shoulder abduction and external rotation by reinnervating the supraspinatous and infraspinatous muscles. A simultaneous transfer to the axillary nerve yields much better results in shoulder abduction and is best achieved following a nerve transfer between the triceps branch of radial nerve and the axillary nerve.

Donor nerves in restoration of elbow flexion include ulnar and or median nerve fascicles , medial pectoral nerve , intercostal nerves  , phrenic nerve  , thoracodorsal nerve, and spinal accessory nerve . An intercostal nerve contains no more than 500 motor fibers , hence at least two or three intercostals nerves (T3, T4 and T5) are transferred to the musculocutaneous nerve. Chuang et al  and Gu et al  have popularized the transfer of phrenic nerve to musculocutaneous nerve (either directly or with a sural nerve graft).Phrenic nerve to  spinal accessory nerve transfer  has the disadvantage of requiring a long nerve graft to reach the musculocutaneous nerve . In the exposure of intercostals nerves a semicircular incision is extended from axilla to the chest along the infraareolar region. In restoration of elbow flexion, the deep central branches of the third, fourth and fifth intercostals nerves are dissected up to the costochondral junction and transferred laterally to the musculocutaneous nerve.

Fascicular nerve transfers (ulnar and median)– A longitudinal incision is made along the anteromedial aspect of upper arm. The musculocutaneous nerve is identified after it has traversed the coracobrachialis muscle. In its distal course the musculocutaneous nerve gives off its motor branches to the biceps and brachialis muscles. A longitudinal epineurotomy is made in the ulnar nerve at the level of the biceps motor branch and an isolated fascicle of the ulnar nerve is sutured end to end to the biceps motor branch. In a similar fashion a fascicle of the median nerve is coapted with the motor branch to the brachialis muscle.

Surgery for brachial plexus injury: Management strategy

C5 – C6 and upper truncal injury
An upper truncal injury with intact nerve roots is amenable to nerve graft repair. In C5-C6 root avulsion injury nerve transfers offer far superior results over tendon/ muscle transfers or shoulder arthrodesis . Nerve transfer between the distal spinal accessory nerve and the suprascapular nerve through the posterior approach restores useful range of shoulder abduction and external rotation. A simultaneous axillary nerve neurotization in the quadrilateral space further improves the range of shoulder abduction by reinnervating the deltoid muscle.

Elbow flexion is best achieved either by biceps reinnervation, or both biceps and brachialis reinnervation. In C5-C6 injuries intraplexal donor nerves provide better functional results than the extraplexal nerves (spinal accessory, phrenic, or intercostal nerves).The bifascicular nerve transfer between the ulnar and median nerves and the biceps and brachialis branches of the musculocutaneous nerve, has become a standard procedure in restoration of elbow flexion in C5- C6 root avulsion injuries. Sparing of single fascicle from the ulnar or median nerve does not result in any subjective deficit in hand function. Preoperative and postoperative evaluation of pinch strength, grip strength and two point discrimination at the pulp of little and index fingers usually remain unaltered .There is no added advantage in fascicular selection using a nerve stimulator while performing the fascicular nerve transfers.

C5 – C7 injury
In addition to the deficits observed in C5-C6 injuries these patients find difficulty in extension of elbow and wrist. Therefore triceps branch of radial nerve cannot be used for neurotization of axillary nerve. The lack of elbow extension leads to difficulty in putting the hand in space and reaching out on objects which affects prehensile functions. In these injuries reconstruction is similar to C5-C6 injuries, however long head triceps branch can be neurotized by 3rd & 4th intercostals nerves. When C6 root is available, it can be used to reconstruct the radial nerve. However it is important to note that delicate balance is required between elbow flexion and extension. If triceps becomes too powerful, it may adversely affect elbow flexion.

C5 – T1 injury
This is a severe injury characterized by flail upper limb. The first priority of reconstruction is elbow flexion followed by shoulder abduction. The hand reanimation is aimed at achieving protective sensation and some finger flexion. In these patients regaining some useful function for their daily activities is aimed at. In case of preganglionic injuries where no graftable root is available, nerve transfers is undertaken to achieve above reconstruction. A single stage reconstruction can be performed in 3 to 5 months post injury. The spinal accessory is used to neurotize  suprascapular nerve and 3rd,4th,& 5th Intercostal nerves are used to neurotize musculocutaneous nerve. To regain protective sensation in hand and achieve finger flexion contralateral C7 (CC7) is used to neurotize median nerve using vascularised  ulnar nerve graft.17 Later to achieve hand stability wrist arthrodesis and thumb fusion can be performed.  Due to long graft and prolonged regeneration time the results of vascularised ulnar graft are unpredictable. Wang et al reported the use of direct cooptation of contralateral C7 root to injured lower trunk by a modified prespinal route. Out of 75 patients 35 also required humerus shortening by 3 to 4.5cms. In 47 patients they also used CC7 to neurotize musculocutanaous nerve through bridging antebrachial cutanous nerve arising from lower trunk. They reported successful outcomes in more than 50% of patients with greater than M3+ power in target muscles. Doi et al have described double free functioning muscle transfer using gracilis for achieving hand prehension, elbow flexion in total palsy. The details of this procedure are described in the succeeding paragraphs. They have reported that most of the patients were able to hold a can and could lift heavy objects.  In post ganglionic injuries where graft-able roots are available, cable nerve grafts are used to reconstruct shoulder and elbow functions. Bertelli et al in their cohort of patients with total palsy 87% had graft-able roots. When C5 root is available, this root is used for neurotization of distal muscles. To achieve shoulder functions we transfer spinal accessory to suprascapular nerve and if C5 root is found graftable then it is neurotized to lateral cord using long cable grafts from sural nerve. When C6 is also found to be graftable it is used to neurotize the posterior cord using cable grafts. Our preference is therefore for shorter cable grafts.

C8 – T1  injury
These are uncommon injuries accounting for about 3% of all brachial plexus injuries.Hand functions are poor with preserved shoulder and elbow functions. The reconstruction aims to achieve prehension with protective sensation. Nerve transfers in form brachialis branch of musculocutaneous nerve to anterior interosseous nerve can be done to achieve grasp functions of hand.18 This however requires an interposition nerve graft. Alternatively brachialis branch can be transferred to posterior fascicular group of median nerve. The posterior fascicular group at brachialis group is composed of anterior interosseous nerve responsible for finger flexion. To restore finger flexion, motor branch to the brachioradialis muscle has been transferred to the anterior interosseous nerve in the management of lower plexus lesions.19

Prespinal route in contralateral C7
To reduce the distance to the target nerves, grafts connected with the contralateral nerve root, have been placed underneath the anterior scalene and longus colli muscles, and then passed through the retro-esophageal space to neurotize the recipient nerve.20

Infraclavicular injury
These are stretch injuries of brachial plexus and involve the peripheral nerves like axillary,musculocutaneous or radial nerves. Cord injuries may also occur in presence of severe trauma. They account for about 15% of all brachial plexus injuries. They are often associated with shoulder dislocation, or fractures of scapula and humerus and vascular injuries. Hence these injuries are challenging to deal with. Surgical exposure is by infraclavicular incision along the deltopectoral groove and pectoralis major is required to be detached from its insertion. The dissection is often tedious due to extensive scarring, previous surgeries and major vessels of upper limb in closed vicinity entrapped in dense fibrosis. Surgical options in their management include neurolysis, direct nerve repair and nerve grafting.

Secondary procedures in brachial plexus injury
A sizable number of patients fail to recover following primary nerve reconstruction. Also there is a group of patients who report more than a year after injury when nerve repair is not feasible. Such cases can be rehabilitated by secondary procedures such as tendon or muscle transfers, free functioning muscle transfers, osteotomies and arthrodesis.

Conclusion
In the management of brachial plexus injuries, an incorporation of micro surgical techniques in neurolysis, nerve repair, nerve grafting and nerve transfer has made possible to restore a functioning limb in many of the patients with brachial plexus injuries, which was considered a difficult or an impossible task just two decades back. An early repair within 6 months of injury is important for a successful outcome. Patients reporting late may be benefited with secondary muscle and skeletal procedures.

Surgery for brachial plexus injury: Upper root avulsions

In C5,C6 root avulsions the proximal root stumps are not available for grafting, hence repair is based on nerve transfer or neurotization. Restoration of elbow flexion takes priority in functional reconstruction, followed by shoulder abduction and external rotation. Reinnervation of musculocutaneous nerve has been achieved with transfer of a variety of donor nerves; the spinal accessory nerve, the medial pectoral nerve, the phrenic nerve, the thoracodorsal nerve and the intercostals nerves. The functional results have been unpredictable with the use of phrenic nerve, medial pectoral nerve and the thoracodorsal nerve. Use of distal end of spinal accessory nerve requires long nerve graft and results are far from satisfactory. Multiple donor nerves are required while using the intercostals nerves.

Selective neurotization of biceps and brachialis muscles with part of ulnar and median nerves have produced consistently good functional results without notable impairment of hand function.

Transfer of the spinal accessory nerve to the suprascapular nerve produces an average of 45 degrees of shoulder abduction (range from less than 20 to 80 degrees). Recently many surgeons have recommended nerve transfers to both the suprascapular and axillary nerves to achieve better results. Transfer of motor branch to long head of triceps to anterior branch of axillary nerve produces minimal functional loss and is compensated easily by the remaining of the triceps and the teres muscle group.

C5 and C6 palsies occur in 15 to 20 percent of supraclavicular plexus injuries.Repair of these injuries offer good prognosis because the hand functions are preserved. If the injury is in the roots in the scalenic area or upper trunk, there is a good possibility for nerve repair with a satisfactory result. In C5 and C6 root avulsions, nerve repair is not possible and nerve

transfers offer far superior results over tendon/ muscle transfers or shoulder arthrodesis. It is well accepted that the two main priorities in nerve transfers are the restoration of elbow flexion and shoulder abduction. Elbow flexion has been achieved with many donor nerves including the intercostal nerves, medial pectoral nerve, phrenic nerve, thoracodorsal nerve, spinal accessory nerve and recently introduced Oberlin transfer. An intercostal nerve contains no more than 500 motor fibers, hence at least two or three intercostals nerves (T3, T4 and T5) are coapted with the motor component of musculocutaneous nerve. Some surgeons do not recommend intercostals to musculocutaneous transfer as the surgery is challenging and time consuming, results are not consistent, and life threatening complications have been observed.

Transfer of medial pectoral nerve to the musculocutaneous nerve is one of the most controversial procedures. In 1948, Lurje described the use of this nerve as a donor in patients with Erb’s palsy. Thereafter only a few reports of the use of this nerve transfer were published. Some authors do not recommend this type of nerve transfer at all. Chuang et al and Gu et al  have popularized the transfer of phrenic nerve to musculocutaneous nerve (either directly or with a sural nerve graft). This procedure again has not gained wide acceptance amongst the western surgeons as it sacrifices an important motor nerve, contraindicated in children and can not be combined with simultaneous intercostals nerve transfer.

The spinal accessory nerve has the disadvantage of requiring a long nerve graft to reach the musculocutaneous nerve.

Transfer of a single fascicle of ulnar nerve to the motor branch of biceps and a fascicle median to the brachialis have produced the most promising results as there is no wastage of any donor nerve fibers to the sensory part of musculocutaneous nerve. Since the nerve transfer is performed close to

the target muscle, the return of function is faster. This technique requires no special re-education of the muscle. Sparing of 1 or 2 fascicle form the ulnar and median nerves does not result in any subjective deficit of hand function. Preoperative and postoperative evaluation of pinch strength, grip strength and two point discrimination at the pulp of little and index fingers remain unaltered.

Shoulder stability and abduction can be restored by arthrodesis, muscle tendon transfer and nerve transfers. Shoulder arthrodesis yields a poor range of motion. It is difficult to achieve satisfactory abduction by muscle/ tendon transfers with use of trapezius, levater scapulae, sternocleidomastoid or latissimus dorsi muscles. Nerve transfer, however, provides good range of shoulder abduction and stability. Transfer of distal spinal accessory nerve to the suprascapular nerve restores an average of 450 of abduction and some external rotation by reactivating the supraspinatous and infraspinatous muscles. A simultaneous transfer of suprascapular nerve and axillary nerve yields much better results when adequate donors are available. Axillary nerve neurotization can be performed through an anterior approach using phrenic nerve, distal spinal accessory nerve, intercostal nerves or medial pectoral nerve as donor nerves. This approach not only requires nerve grafts but also results in dilution of nerve fibers entering the deltoid muscle. A posterior approach allows the transfer of nerve to the long head of triceps (which contains mainly motor fibers) to the anterior branch of axillary nerve which innervates the anterior and middle deltoid muscle. This transfer avoids the misdirection of the regenerated axons in to the cutaneous branch and teres minor. The functional loss is minimal and is compensated by remaining 2 heads of triceps and the teres muscle group.

CONCLUSION
Selective neurotizations closer to the motor end plates allow an early return of function. The return of power is much superior to the other conventional methods of nerve transfers. The functional loss is minimal. Multiple nerve transfers are preferred in the management of C5,C6 root avulsion injuries.

Surgery for brachial plexus injury: Posterior approaches

Spinal accessory nerve to suprascapular nerve transfer
Patient is placed in the lateral position with head of the operating table raised by 40 degrees . An incision is made parallel to the spine of scapula. The trapezius muscle is elevated from the scapular spine and the space between the trapezius and the supraspinatus muscles is exposed. A thin layer of adipose tissue may occasionally be observed between the two muscle layers. Neurovascular structures covered by a thin epimysium are identified on the undersurface of the trapezius. The SAN is then cautiously isolated from the thin vessels and looped in a vascular tape. The nerve is then traced as distally as possible in order to allow a tension-free anastomosis with the SSN, and finally sectioned with a pair of sharp scissors.

Working laterally along the upper border of scapula, a strong downward traction is applied on the upper border of the supraspinatus muscle to reveal the glistening white suprascapular ligament overlying the suprascapular notch. Suprascapular vessels running superficial to the suprascapular ligament are clipped, and the ligament is divided under direct vision safeguarding the underlying SSN. The nerve is isolated in the fatty tissue just proximal to the suprascapular notch, and divided. The SAN is sutured to the distal segment of the SSN with 10-0 nylon suture under an operating microscope . The trapezius muscle is then sutured back to the spine of scapula using a 3-0 polyglactin suture. Finally, the skin incision is closed without a drain.

Triceps branch of radial nerve to axillary nerve transfer (Somsak transfer)
Patient is placed in the supine position with a silicone pad beneath the affected shoulder, and the affected arm resting on the chest. An incision is made along the posterolateral aspect of the arm, with the upper part of incision curving along the posterior border of the deltoid, and the lower part centered over the triangular space in between the long and lateral heads of the triceps muscle.

The radial nerve and its branch to the long head of triceps are identified in the triangular space. A partial division of the lower edge of teres major enhances the exposure of the motor branch to the long head of triceps muscle. This motor branch that usually terminates into two or three smaller branches is sectioned close to the triceps muscle.

The upper part of the incision exposes the quadrilateral space and the AXN, dividing into its anterior and posterior branches. The anterior branch is dissected intraneurally and transected as proximally as possible.

The triceps branch to the long head is then flipped 1800 and sutured to the anterior branch of the axillary nerve with 10-0 nylon suture under an operating microscope and skin incision is closed without a drain.