Outcomes of treatment for adult brachial plexus injuries

Section Three  Adult brachial plexus palsies

CHAPTER

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Outcomes of treatment for adult brachial plexus injuries Olawale A.R. Sulaiman, MD, PhD, FRCS(C), David G. Kline, MD

SUMMARY BOX 1. Clean, sharp lacerations of the brachial plexus should be repaired within 72 hours. Blunt transections are best repaired in a delayed fashion. 2. Progressive neurologic deficits may be indicative of an enlarging hematoma, arteriovenous fistula, or pseudoaneurysm. 3. Blunt or traction injuries of the brachial plexus that show no evidence of spontaneous recovery have favorable outcomes after surgical intervention. 4. Use of intraoperative nerve action potential recordings is critical for assessing extent of nerve injury and serves to guide the surgeon’s decision-making. 5. Functional outcomes from spontaneous recovery or operative intervention are significantly improved by the use of physical and occupational therapies and secondary reconstructive procedures.

Introduction Management of brachial plexus (BP) injuries has changed significantly over the past century, especially with regard to our understanding of neurobiology, pathophysiology, and pathology of nerve injuries and regeneration, as well as the microsurgical repair of injured nerves.1,2,3,4,5,6 Advancements in the clinical diagnosis of nerve lesions, development of comprehensive and evidence-based treatment algorithms, and optimization of the intraoperative decision-making process resulting from the introduction of intraoperative nerve action potential (NAP) recordings paved the way for better management of patients inflicted with peripheral nerve and BP injuries.2,7 Another benefit of a rather standardized treatment approach is the ability to © 2012, Elsevier Inc DOI: 10.1016/B978-1-4377-0575-1.00024-1

6. Of brachial plexus traction injuries, C5 and C6 injuries have the most favorable outcomes with regard to spontaneous recovery (30%), followed by C5, C6, C7 injuries (16%), and C5–T1 injuries (4%). 7. With brachial plexus traction injuries that progress to surgical intervention, C5 and C6 injuries have the best functional outcomes. 8. C5–T1 lesions remain difficult to repair surgically, and operations are considered salvage-like in nature. 9. Functional outcomes after brachial plexus injuries are improving with advancements in nerve transfer techniques. 10. A limited time window exists for optimal nerve regenerative support and subsequent functional recovery.

systematically study clinical outcomes of patients with nerve injuries after microsurgical repair. Multiple series of functional outcomes after nerve injuries have been reported, both in civilian populations and in war veterans.8,9,10 In this chapter, we discuss briefly our approaches in the management of patients with BP injuries, with particular emphasis on clinical outcomes after microsurgical repair.

Causes of surgical nerve injuries The BP can be injured either directly as in stab injuries where elements of the BP are sharply transected, or indirectly as in stretch injuries. Recently, traumatic nerve injuries have been classified based on the biomechanics of the injuring

Outcomes of treatment for adult brachial plexus injuries

processes (Figure 24.1 (part 1)).11 This classification is different from the neuropathologic classification of nerve injuries by Sunderland (Table 24.1), as it emphasizes the mechanism of injury, which is important in deciding the best treatment option for a given nerve injury. BP injuries most often are caused by high energy forces that result in injuries such as transection, contusion, stretch, traction, and/or avulsion. However, BP injuries may also result from compressive neuropathies such as thoracic outlet syndrome, which are due to chronic or repetitive low energy forces (Figure 24.1 (part 2)). BP injuries from injections, radiation, and thermal energy involve rather heterogenous combinations of different injuring factors, but for the purposes of analysis, they are grouped together as a complex group of nerve injuries (Figure 24.1 (part 3)).11

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Approach to clinical diagnosis As with every other surgical discipline, the importance of detailed but relevant clinical patient history and mastery of physical examination of the patient as it relates to lesions of the BP cannot be overemphasized. Mastery of these skills combined with prudent use of ancillary tests, such as electromyography (EMG) and imaging studies, will guide the treating physician to an accurate diagnosis and localization of BP injuries (Table 24.2). It is of utmost importance to entertain a broad differential diagnosis and perhaps only accept the diagnosis of BP injury once other causes of upper extremity dysfunction have been considered. This approach is especially important when dealing with controversial diagnostic entities such as Parsonage-Turner

1. Medium to high energy - mechanical

Contusion/stretch/ traction

Transection

Partial

Complete

Avulsion

With lesion – Without lesion Pre-ganglionic Post-ganglionic in-continuity – in-continuity

With lesion – Without lesion Sharp Blunt in-continuity – in-continuity transection transection

2. Low energy compressive/ischemic lesion

Compressive neuropathies

Compartment syndromes

3. Complex

Direct intraneurial

Chemical/ injection

Radiation-induced nerve injuries

Indirect perineurial

Combined

Thermal

Electrical

Combined

Figure 24.1  Classification of surgical traumatic nerve disorders. 345

Section Three  Adult brachial plexus palsies

Table 24.1  Nerve injury grading (Sunderland Grading Scale)

Injury grade

Myelin

Axon

Endoneurium

Perineurium

I (Neuropraxia)*

+/−

II (Axonotmesis)*

+

+

III

+

+

+

IV

+

+

+

+

V (Neuromesis)*

+

+

+

+

Epineurium

+

+ denotes anatomical structures affected by injury. * Seddon grading system

and thoracic outlet syndrome. Once a diagnosis of BP injury has been established, surgical treatment of the lesion is dictated by nature of the injury (open versus closed), acuity of the injury (early versus delayed presentation), and findings on clinical, electrodiagnostic, and imaging studies (Figure 24.2).

Indications and relative contraindications for surgery Lacerations of the BP Transection of the BP may occur when soft tissues surrounding the BP sustain lacerating injuries. These injuries tend to be either sharp or blunt. Sharp injuries to the BP are often caused by stab injuries inflicted by knives, falls through glass windows, or by exploding glass in factory or automobile accidents. Blunt injuries are caused by automobile metal fragments, fan or motor blades, chain saws, and animal bites around the neck. Patients with lacerating injuries to the BP often have associated vascular injuries and/or airway difficulties; therefore, all initial efforts should be directed toward stabilizing the patient’s potential life-threatening orthopedic or vascular injuries. Securing the patient’s airway, breathing, and hemodynamic stability take precedence over any nerve injuries. Once initial resuscitative efforts are completed, the fundamental goal of managing lacerating injuries of the BP is to establish an accurate diagnosis as soon as possible in an attempt to improve prognosis. Once diagnosis of a laceration of the BP has been established, urgency of treatment is dictated by the nature of the open wound and the cleanliness of the transected nerve edges: 346

Table 24.2  Role of nerve conduction studies and imaging in the diagnosis of nerve lesions With regard to EMG, the following should be emphasized:  EMG should be more than just conduction studies and must include muscle sampling.  Patients can have clinical muscle function despite de-innervational changes.  Patients can have persistent paralysis despite nascents or reduction in denervational changes, such as fibrillation and denervation potentials.  Muscles related to neighboring nerves or plexus elements can show persistent EMG changes despite good function.  Conduction studies are not always useful, especially for ulnar nerve and brachial plexus cases. Imaging studies are important, but:  MRI is most useful for tumors; occasionally it may also be useful for entrapments and injury.  To date, in most institutions, MRI is not yet a substitute for CT-myelogram, especially when investigating root avulsions.  Don’t forget plain x-rays! It is possible to pick up parrot’s beak of the C7 spinous process or humeral condyle on plain x-rays.

(a) Sharp nerve transection in a stable, clean soft tissue environment requires primary end-toend neurorrhaphy within 72 hours. (b) Progressive neurologic deficit with/without progressive pain syndrome may be indicative of an enlarging hematoma, arteriovenous fistula, or pseudoaneurysm and indicates early intervention with participation by a vascular surgeon. (c) Nerve laceration within a severely contaminated wound requires aggressive and

Outcomes of treatment for adult brachial plexus injuries

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Brachial plexus injury

Open injury

Closed injury

Laceration/transection

Probable lesion in continuity from stretch/contusion, compression/ischemic, electric, injection, iatrogenic injuries

Sharp Nerve sharply divided

Blunt Nerve contused Epineurium ragged

Primary or early repair (within 72 hours)

Evaluation

‘Tack’ to adjacent planes Secondary repair at 2 to 3 weeks

Physical therapy as early as possible

Clinical assessment (motor, sensory, autonomic) Serial EMGs, radiographs, myelogram, CT, MRI, physical therapy

No regeneration (no recovery)

Focal lesion

Lengthy lesion

Follow for 2 to 3 months

Follow for 4 to 5 months

Regeneration (recovery)

Exploration/NAP recordings

+NAP (regenerative)

–NAP (non-regenerative)

Neurolysis or +NAP (preganglionic)

Resection and repair or pre-ganglionic

Nerve transfer(s)

Nerve transfer(s)

Figure 24.2  Modified algorithm for surgical management of a brachial plexus injury.

repeated irrigation and debridement of the wound to remove all necrotic tissues and eliminate risk of sepsis. Delayed repair of the nerve injury is employed, and the method of repair varies from neurolysis, direct end-toend repair, graft repair and/or nerve transfers,

depending on intraoperative findings and NAPs. (d) Blunt injury to nerve endings at the injury site requires secondary repair. If possible one can “tack down” nerve stumps with a suture to adjacent fascial or muscle planes so that 347

Section Three  Adult brachial plexus palsies

retraction of the nerves is lessened and secondary repair can be achieved by epineurial suture repair instead of graft repair.

Gunshot wound to BP Gunshot injuries to the BP constitute the second largest category of injuries involving the BP after stretch/contusion. Gunshot wounds to the BP hardly ever require immediate nerve repair because they most often cause neurmas-in-continuity, although in 10% to 15% of cases, blunt transection of BP elements occurs. Indications for elective nerve repair of gunshot injuries to the BP are listed below: (a) Complete loss of function persistent in the distribution of one or more elements. (b) No improvement detected clinically or by electrodiagnostic studies in the early months following injury. (c) Loss of function in the distribution of at least one element usually helped by operation, such as C5, C6, C7, the upper or middle trunk, or the lateral or posterior cords or their outflows. (d) Surgery is not performed on injuries restricted to the lower trunks unless pain is a severe problem. (e) Incomplete loss of function complicated with pain not alleviated pharmacologically. (f) Pseudoaneurysm, clot, or fistula involving the plexus. (g) True causalgia requiring sympathectomy.

Stretch Injuries to the BP Stretch injuries constitute the most common type of injury to the BP and are usually caused by motor vehicle accidents, particularly those involving motorcycles. Stretch injuries to the BP can occur during sports and/or recreational activities such as football, bicycling, skiing, wrestling, gymnastics, and even golf. Regardless of the cause of injury, the biomechanics of stretch injuries always involve distractive forces in which the head and neck are usually pushed in one direction and shoulder and arm in another direction. This results in severe stretch to soft tissues, including nerve and, less frequently, vessels. Management of stretch injuries to the BP has evolved significantly over the last century, beginning with predominantly non-surgical and 348

musculoskeletal reconstructive operations and amputations to direct surgical repairs. Over the last 2 decades, our understanding of the pathophysiology of poor regeneration and functional recovery has improved significantly and, with it, the evolution of innovative approaches to microsurgical management of BP injuries.1,3,12,13 Likewise, better understanding of the natural history of BP injuries with regard to the potential for spontaneous recovery and timing of microsurgical repair has improved our capability to optimize patient benefit from surgical treatment. A combination of suboptimal clinical results despite excellent direct microsurgical repair, and our appreciation of proximo-distal discrepancy in the reinnervation of denervated muscles after BP injuries, created a receptive audience for Narakas when he re-popularized neurotization (ie, nerve transfers) procedures about 3 decades ago.14 We have adopted an approach to perform direct microsurgical repair for BP injuries whenever feasible, supplemented with neurotization procedures. Our indications for surgical exploration and repair of BP stretch injuries are as follows: (a) Lack of clinical or electrodiagnostic evidence of spontaneous recovery 3 to 4 months after injury. (b) Possibility of a direct repair of at least a portion of the BP elements favorable for repair, usually C5, C6, C7 and their more distal outflows. (c) Lack of contraindications for surgical exploration.

Approach to intraoperative management of BP lesions Microsurgery The key principles in nerve surgery include (1) thorough understanding of the topographic anatomy of the injured nerve (Figures 24.3, 24.4, 24.5); (2) mastery of the required incision and surgical approaches (Figures 24.6, 24.7); (3) adequate surgical exposure of the proximal and distal stumps of the injured nerves as well as the associated nerve branches and blood vessels (Figures 24.8, 24.9); (4) adequate magnification with the use of either the operating microscope or surgical loupes; (5) use of micro-instruments to minimize surgical trauma to the already traumatized nerves and/or branches; (6) careful application of bipolar coagulation only

Outcomes of treatment for adult brachial plexus injuries Sternocleidomastoid muscle Sternocleidomastoid muscle Scalenus anticus muscle

Brachial plexus Phrenic nerve

Clavicle

Omohyoid muscle Clavicle Omohyoid fascia

First rib

Figure 24.3  The clavicular head of the sternocleidomastoid muscle on the right has been divided to illustrate the location of the phrenic nerve over the scalenus anticus. Once the phrenic nerve has been dissected free and guarded, the scalenus anticus can be divided or a section of it removed after the surgeon has seen that the subclavian artery is free from its posterior surface and the vein from its anterior surface.

to the epineurial and intrafascicular bleeding points to minimize damage to the nerve itself.

Intraoperative nerve action potential (iNAP) Lack of clinical and electrodiagnostic evidence of functional recovery 3 to 4 months after nerve injury are indications of lack of adequate reinnervation of denervated muscles and/or remyelination to generate muscle contractions. The senior author (DGK) pioneered the application of iNAP to the evaluation of axonal regeneration across a segment of damaged nerves.2,7 Intraoperative evaluation of axonal regeneration using iNAP is important, because it prevents inadvertent resection of nerves that still have the potential for spontaneous recovery. Appropriate intraoperative surgical decisions can be made with regard to the need for surgical resection of severely damaged nerves that have no response on iNAP (flat) and the subsequent need for direct or graft repair, or neurolysis, and continuation of observant non-surgical treatment if the damaged nerves have positive NAPs. Intraoperative NAPs can also help determine the proximal extent of healthy axons in injured nerves.

Clavipectoral fascia Pectoralis major muscle Pectoralis minor muscle

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Scalenus posterior muscle Scalenus medius muscle Levator scapula muscle Upper trunk Middle trunk Lower trunk Subclavian artery Subclavian vein Subclavius muscle First rib

Figure 24.4  Sagittal section of left neck at midclavicular level. The spinal nerves that make up the brachial plexus reside in the posterior triangle of the neck by running posterior to the scalenus anticus and anterior to the scalenus medius. The phrenic nerve is bound to the anterior aspect of the scalenus anticus.

In addition, iNAP allows for early evaluation of nerve injuries and a determination of the extent of nerve damage. It can be applied 2 to 3 months after most focal injuries, and 3 to 4 months in less-focal lesions caused by stretch/contusion or gunshot injuries. With its application, the surgeon can sort out the management strategy for approximately 70% of nerve injuries in which nerve segments appear continuous with a variable amount of swelling and/or epineurial scar and yet are nonfunctional. NAP recordings can document the extent of a partial injury or prove that there is a neurapraxic block in the early weeks after the injury. When iNAP is applied months after injury, it can differentiate an axonotmetic lesion (positive NAP across the lesion) from a neurotmetic injury (negative NAP across the lesion).2,7

Nerve repair techniques and nerve grafts The surgical objective of the repair of any severed peripheral nerve involves either microsurgical realignment of the injured nerve stumps (ie, primary neurorrhaphy) or the use of an autologous nerve graft to bridge a larger defect. A thorough understanding of the surgical anatomy of BP exposure at supraclavicular, clavicular, and infraclavicular levels allows the surgeon to expose key elements 349

Section Three  Adult brachial plexus palsies Figure 24.5  The infraclavicular brachial plexus resides underneath the pectoralis minor, which need to be mobilized and divided in order to expose the plexus elements.

Coracoid process

Pectoralis minor muscle

Short head, biceps muscle

Upper trunk Middle trunk Lower trunk Clavicle

Long head, biceps muscle Short head, biceps muscle

Pectoralis minor muscle

Triceps muscle

Figure 24.6  Positioning and incision for anterior exposure of supraclavicular and infraclavicular plexus. Neck incision is just lateral to sternocleidomastoid muscle, angling over clavicle to reach the shoulder. In the shoulder region, the incision runs in the deltopectoral groove.

350

Figure 24.7  Incision for exposure of the infraclavicular brachial plexus. Incision begins below the clavicle, is in the deltopectoral groove, and runs toward the axillary level.

Outcomes of treatment for adult brachial plexus injuries C8 root

24

Phrenic nerve T1 root

Omohyoid muscle Transverse cervical artery and vein

C7 root C6 root C5 root Upper trunk Accessory nerve

Suprascapular artery and vein Lower trunk

Descending cervical plexus

Dorsal scapular artery Transverse cervical artery and vein

Omohyoid muscle Middle trunk

Figure 24.8  Dissection of supraclavicular plexus on the right side, depicting exposure of spinal nerves, trunks, and divisions of the plexus. The take-off of the phrenic nerve from C4 and the descending plexus are seen, as well as contributions from C5, C6, C7, C8, and T1 to form the upper (C5 + C6), middle (C7), and lower (C8 + T1) trunks of the brachial plexus. Triceps muscle Antebrachial cutaneous nerve Ulnar nerve Medial cord to ulnar nerve Pectoral nerve branches

Radial nerve Triceps branches

Posterior humeral circumflex artery Latissimus dorsi muscle Axillary nerve

Axillary artery Pectoralis minor muscle

Medial nerve Anterior humeral circumflex artery Posterior division contribution of lower trunk to posterior cord

Coracobrachialis muscle

Posterior division contribution of upper trunk to posterior cord

Musculocutaneous nerve

Deltopectoral vein

Profunda artery Nerve to Pectoralis minor muscle coracobrachialis muscle

Lateral cord to median nerve

Figure 24.9  Exposure of the entire right infraclavicular plexus. Dissection at this site is difficult as well as tedious. This is especially so when there is scar from prior surgery or extensive injury involving major vessels. Cords of the plexus are positioned around the axillary artery. Note 1) position of the profundus arterial branch between the radial and axillary nerves, 2) medial pectoral branches arising from the medial cord and their interplay with the lateral cord pectoral branches, and 3) origin of the coracobrachialis branch and musculocutaneous nerve from the lateral cord just before the median is formed. 351

Section Three  Adult brachial plexus palsies Sternocleidomastoid muscle

Omohyoid muscle

External jugular vein Transverse cervical artery and vein

Scalenus anticus muscle Phrenic nerve

Pectoralis major muscle

Scalenus medius muscle Transverse cervical artery and vein

Clavicle Suprascapular artery and vein

Figure 24.10  Supraclavicular dissection on the right side. The cervical fat pad is being dissected away from underlying transcervical vessels and the omohyoid. The clavicle is displaced inferiorly by a large vein retractor to expose the suprascapular artery and vein. The external jugular vein is retracted superiorly. The phrenic nerve can be seen lying anterior to the scalenus anticus.

of the BP, even after stretch injuries where there is abundant scar tissue formation (Figures 24.10, 24.11, 24.12, 24.13, 24.14, 24.15). Wide exposure of BP elements and the application of iNAP guide the surgeon’s decision-making process with regard to microsurgical repair of injured nerves with or without nerve grafting. The nerve grafting technique was first reported between the years 1870 and 1900, but Hanno Millesi3 re-popularized the concept of using nerve grafts to bridge large defects to avoid the detrimental effects of suturing nerve stumps under tension.15 His work demonstrated that nerve grafting without tension was superior to epineurial suture under tension, and that tension at the repair site induces scar formation. Therefore, nerve repair without tension is most desirable, because the more scar tissue present at the repair site, the less satisfactory is functional recovery. Tension across a direct suture repair decreases blood flow and promotes proliferation of connective tissue within the nerve, which may block effective axonal regeneration.6,15 Acute, excessive stretch may cause intraneural hemorrhage resulting in scar formation and axoplasmic degeneration; subsequent maturation of scar tissue may shrink and constrict nerve fibers and may result in formation of a neuroma-in-continuity.6 352

Middle trunk

Lower trunk

Suprascapular artery and vein Upper trunk

Suprascapular Dorsal scapular nerve artery

Omohyoid muscle

Figure 24.11  The right clavicle has been displaced inferiorly in order to visualize the suprascapular vein and artery, around which a Munyon is placed and ligated. An arterial branch (dorsal scapular) from the subclavian artery lies superior to the lower and middle trunks at a divisional level, and in this drawing goes between the divisions of the upper trunk. In this case, the scalenus anticus has been displaced along with the overlying phrenic nerve anteriorly.

Outcomes of treatment for adult brachial plexus injuries

However, whenever there are small-to-moderate gaps, it may be preferable to mobilize nerve ends to allow direct nerve repair (without tension), which results in better functional recovery than graft repair. Nerve grafting techniques include the use of either a free nerve graft or a vascularized nerve graft in the form of pedicle grafts or as a free

Pectoralis major muscle

Pectoralis minor muscle Deltopectoral vein Figure 24.12  The pectoralis major muscle is split in the direction of its fibers. Muscle both medial and lateral to the split is detached from the inferior surface of the clavicle. The deltopectoral artery and vein are ligated and the pectoralis minor is visualized.

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vascularized graft transfer.15 Nerve grafts can be classified according to their biological origin. Autografts are harvested from the same individual, allografts (or homografts) come from an individual of the same species, and xenografts (or heterografts) originate from another species. Autografts, which are the “gold standard” for nerve grafting surgery, are harvested from the same patient and do not pose immunological problems. Currently, donor nerves used for nerve grafting are commonly expendable sensory nerves that can be harvested without significant morbidity, except for some loss of sensation at the donor site. Commonly used donor nerves include the sural nerve, lateral antebrachial cutaneous nerve, anterior division of the medial antebrachial cutaneous nerve, dorsal cutaneous branch of the ulnar nerve, and superficial sensory branch of the radial nerve. The choice of donor nerve to be used is dictated by the crosssectional area of the nerve to be repaired, length of the nerve gap, and extent of donor site morbidity. The primary donor nerve for free grafting is the sural nerve, which can be harvested to a length of 30  cm or more and is easily accessible.6,13,15,16 The use of nerve grafts obtained from another human being is warranted in situations when repair of a large defect created by a BP or sciatic nerve injury is limited by an inadequate number of

Pectoralis major muscle

Deltopectoral vein Pectoralis minor muscle Right anterior axilla Figure 24.13  A finger can be inserted under the tendon of the anterior-lying pectoralis minor from both superior and inferior aspects. Once the tendon is divided, the pectoralis minor can be retracted with self-retaining retractors, thereby revealing infraclavicular plexus elements. 353

Section Three  Adult brachial plexus palsies

Medial cord Pectoral nerve branches Antebrachial cutaneous nerve Ulnar nerve Radial nerve Median nerve Musculocutaneous nerve Axillary vein Axillary artery Nerve to coracobrachialis muscle Lateral cord Figure 24.14  Weitlaner retractors are placed in the pectoralis major and sometimes on either side of the transected pectoralis minor, and opened to expose the infraclavicular plexus and vessels. A vein retractor is displacing the inferior portion of the axillary vein. This permits dissection of distal medial cord branches, such as its contribution to the median nerve and the antebrachial cutaneous and ulnar nerves.

Deltoid Deltopectoral Pectoralis major muscle vein (cut) muscle Coracobrachialis muscle Musculocutaneous nerve

Subclavius muscle Lateral cord contribution to median nerve

Pectoralis major muscle

Triceps muscle Biceps brachii muscle Median nerve

Long thoracic nerve Nerve to latissimus dorsi muscle Subscapular artery Latissimus dorsi muscle

Figure 24.15  Both the pectoralis major and pectoralis minor have been sectioned to expose the lateral and medial cords and their relationships to the axillary vein and artery and some of the structures on the lateral chest wall.

available segments from autograft. However, because allografts trigger immunological response and there is risk of rejection, the use of immunosuppressive treatment is required to prevent rejection. Hence, patients receiving this type of nerve graft must be willing to accept the potentially 354

dangerous side effects of the chemotherapeutic agents used. Xenografts are derived from animals of another species and are also used in situations similar to that for allografts and also require the use of immunosuppressive therapy.2 The use of xenografts is, thus far, limited to experimental studies in animals. A posterior subscapular approach to the supraclavicular BP is not used as often as anterior approaches but provides an excellent surgical option to gain access to supraclavicular BP (Figures 24.16–24.21).

Postoperative management Follow-up may be necessary by other specialists as well as by the surgeon. Timing of follow-up visits varies depending on initial outcome, length of time predicted for useful regeneration, and need for physical and occupational therapies (PT/OT) and secondary procedures. The tensile strength of neural repairs is maximal at 3 weeks, so active PT/OT can usually begin after that. On the other hand, if the initial regenerative input is a year away, saving some PT/OT may be necessary, depending on insurance coverage.

Outcomes of treatment for adult brachial plexus injuries

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Levator scapulae muscle

Rhomboid minor muscle

Rhomboid major muscle

Figure 24.16  Posterior subscapular approach to the supraclavicular brachial plexus. The shoulder is abducted and the flexed elbow and forearm are placed on a Mayo stand adjacent to the operating table. This can be lowered or elevated to change position of the scapula. The incision is curved around the medial edge of the scapula. It is usually placed halfway between the scapular edge and the thoracic spinous processes so that the mid-section of the rhomboid muscles can be exposed. Incision extends to the posterolateral aspect of the lower neck.

Trapezius muscle

Figure 24.17  Trapezius muscle is divided halfway between medial edge of the scapula and spine.

Figure 24.18  After division of trapezius, rhomboids are sequentially clamped with large Kelly clamps or Serats and divided. Muscle edges are then marked laterally and medially by heavy sutures, which are tied but not cut. This is done so that rhomboids can be reapproximated with relative accuracy during closure.

Outcomes assessments It is of utmost importance that a universally acceptable numerical grading system for nerve pathologies and outcomes be developed to elevate the field to the scientific level it deserves, and to assist us in the development of management strategies based on reliable data. The most popular grading scale is the British Medical Research Council (MRC) grading system. However, this system has shortcomings, some of which have been addressed in the more recent American systems, such as the Louisiana State University Health Sciences Center (LSUHSC) grading systems. New generation grading systems, which may be borne out of a combination of the above-mentioned systems, must further reflect the lifestyle or practical use of the limb that injury and/or its recovery permits. Published reports on nerve injuries and repairs from both the war era and from civilian experience are invaluable with regard to obtainable treatment goals. The 355

Section Three  Adult brachial plexus palsies Brachial plexus Subclavian artery Subclavian vein

C8 C7 C6 Right posterior approach

Subclavian artery Subclavian vein

First rib

Figure 24.19  A chest retractor has been placed with the blades near the upper thoracic spinous processes and under the scapula. As the retractor is opened, the scapula is rotated laterally to expose posterior aspects of upper ribs. The posterior scalene is detached from the superior surface of the first rib. The more medial segments of the scalenes are removed to begin exposure of the plexus.

Figure 24.20  Intercostal muscle is cleared from inferior and posterolateral aspects of the first rib using a periosteal elevator or Doyen rib dissectors. Sometimes a Munyon passed under the rib can also help clear its muscular attachments.

availability of more sophisticated data gathering and analysis software now facilitates outcome research in times of either war or peace. Given the tremendous advancements in the field of nerve regeneration strategies, nerve conduits, and pain management, analysis of outcomes has never been more important than now.

Functional outcomes after BP repair Based on over 30 years of evaluating and treating over 2500 patients with BP lesions, a standardized (LSUHSC) grading system was developed and used for assessing outcome of surgical patients (Table 24.3).8 This system differs from the MRC system in that the LSUHSC grade 3 includes at least some muscle contraction against mild resistance as well as gravity, whereas grade 2 is against gravity only, which is equivalent to an MRC grade 3. Favorable outcomes are, in our view, patients with element(s) recovering to an LSUHSC grade of 3 or better level. 356

Figure 24.21  Either Leksell rongeurs or a rib cutter is used to resect the rib to and including some of its transverse process medially and to the axillary level laterally. A Weitlaner retractor can be placed with one set of blades on the second rib and another on the soft tissues of the superior neck. The retractor is then opened to expose more of the thoracic outlet region.

Postoperative or recovery grades for the various patterns of supraclavicular stretch injuries after surgery are initially calculated for each element, usually at root or spinal nerve level. These grades (ranging from 0 to 5) are then added together and average

Outcomes of treatment for adult brachial plexus injuries

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Table 24.3  Louisiana State University Health Sciences Center grading system by element of brachial plexus

Overall grading

Grade

Evaluation

Description

0

Absent

No muscle contraction

1

Poor

Proximal muscles contract but not against gravity

2

Fair

Proximal muscles contract against gravity and distal muscles do not contract; sensory grade, if applicable, is usually <2

3

Moderate

Proximal muscles contract against gravity and some resistance; some distal muscles contact against gravity; sensory grade, if applicable is usually 3

4

Good

All muscles contract against gravity and some resistance; sensory grade, if applicable, is 3 or 4

5

Excellent

All muscles contract against moderate resistance; sensory grade, if applicable, 4

Sensory grading

Grade

Evaluation

Description

0

Absent

No response to touch, pin, or pressure

1

Poor

Testing produces hyperesthesias or paresthesias; deep pain recovery in autonomous zones

2

Fair

Sensory response sufficient for grip and slow protection, sensory stimuli mislocalized with some overresponse

3

Moderate

Response to touch and pin in autonomous zones, sensation mislocalized and not normal, with overresponse

4

Good

Response to touch and pin in autonomous zones, response localized but not normal; however, there is no overresponse

5

Excellent

Near-normal response to touch and pin in entire field of plexus element including autonomous zones; stimuli were accurately localized

From Kim D, Midha R, Murovic J, Spinner R: Kline & Hudson’s Nerve Injuries: Operative Results for Major Nerve Injuries, Entrapments, and Tumors. 2nd edition, Elsevier 2008

to obtain the overall grade. For example, if the postoperative grades in a patient with a C5 and C6 stretch injury are 3.5 in the C5 distribution and 4.0 in the C6 distribution, then the average is 3.75, and the overall grade will be 3 to 4. If the initial lesion is a C5, C6, and C7 stretch injury and postoperative grades are C5 = 2, C6 = 4, and C7 = 3, then the average grade will be 3.

Lacerations of the BP At the LSUHSC, 71 patients with lacerations involving the BP were examined and a total of 201 plexus elements were judged to be seriously injured.8 Onethird of patients with lacerating injuries to the BP underwent urgent surgical exploration because

of suspected or angiographically proven vascular injuries. Of the 201 plexus elements, 83 were sharply transected and 61 sustained blunt transaction. There were 57 plexus elements in 20 patients in whom the lesions were in some degree of continuity, despite a lacerating or penetrating mechanism. Twenty-six elements were associated with a positive NAP across the lesion and were treated with neurolysis. Functional outcome is dictated by both the acuity of nerve repair and type of repair. Patients who had only neurolysis or urgent (within 72 hours) and direct repair of the lacerated nerves had the best outcome. Of the 26 elements that underwent neurolysis, 24 (92%) recovered to a grade 3 or better level of function (Table 24.4). Twenty-five (81%) 357

Section Three  Adult brachial plexus palsies

Table 24.4  Outcomes of surgery for patients with brachial plexus lacerations using Louisiana State University Health Sciences Center Scale (n = 71; total number of patients/patients recovering to grade ≥ 3)

In continuity

Sharp transection

Blunt transection

Totals

No. of operative plexus cases

20

28

23

71

No. of plexus elements

57

83

61

201

Neurolysis/results

26/24

0/0

0/0

26/24

Primary suture results

0/0

31/25

0/0

31/25

Secondary suture/results

9/7

12/8

5/3

26/18

Secondary graft/results

22/17

40/21

56/25

118/63

Total elements/results

57/48

83/54

61/28

201/130

Reproduced with permissions from Kline and Hudson’s Nerve Injuries: operative results for major nerve injuries, entrapments and tumors, 2008, with permission)

of 31 primary suture repairs recovered to a grade 3 or better level of function. Patients who had delayed suture repair and graft repair recovered to a grade 3 or better in 78% and 77%, respectively. A grade 3 or better recovery was achievable in 48 (84%) of the 57 involved elements in-continuity and conducted a NAP through their lesion. On the other hand, when referrals were delayed, graft repair was often necessary because of stump retraction and the overall recovery to a grade 3 or better was only 53%. Repairs were delayed by choice in lesions from blunt transections because the extent of damage was initially difficult to assess accurately. Thus, 56 of 61 blunt transections required graft repair, of which 25 (45%) had a grade 3 or better functional outcome. Secondary end-to-end suture was possible in only 5 cases, and 3 (60%) of these had grade 3 or better level of functional recovery. In this category, 28 (46%) of 61 blunt transections had overall recovery of grade 3 or better level of function (Table 24.4).

Gunshot injury to the BP There were 293 plexus elements injured due to gunshot wound in 118 patients.8 Most of the 293 plexus elements that were surgically treated had some gross continuity found on surgical exposure. Only 8% of elements with complete loss distal to the lesion were found to have total physical disruption during surgical exploration. Some lesions-incontinuity recovered spontaneously, and others showed no sign of reversal or reinnervation after 358

several months. In these cases, exploration and intraoperative NAP recording were performed. Of the 293 in-continuity elements that were explored and evaluated, 120 had recordable NAPs and, in response to neurolysis, function improved to grade 3 or better in 94% of these cases (Table 24.5). Elements that did not have early evidence of regeneration usually required repair. Thus, 156 (77%) of the 202 elements suspected to have complete injury required resection and repair, as indicated by intraoperative electrical evaluation. Repairs were relatively effective for predictable elements such as the upper trunk and the C5 and C6 nerve roots, and for lateral and posterior cords and their outflows. Acceptable results were achieved in 73 (54%) of 135 lesions with complete loss repaired by grafts, and in 14 (67%) of 21 cases repaired by end-to-end suturing. In this series, functional outcomes of graft repair were as satisfactory as end-to-end suture repair, perhaps because the grafts used were relatively short (i.e., 1 to 2.5 inches). Recovery occurred in severe C8, T1, lower trunk, and medial cord injuries when the nerve was in-continuity and NAPs were recordable. Graft or end-to-end suture repair of these elements did not result in useful recovery, except in a few pediatric cases. Therefore, surgery is warranted in select cases of gunshot wound to the plexus (Table 24.5).

Stretch injuries to the BP Supraclavicular stretch injuries involved spinal nerves C5-C6 (15%), C5–C7 (20%) and C5–T1

24

Outcomes of treatment for adult brachial plexus injuries

Table 24.5  Outcomes of surgery for 118 patients with gunshot wound injuries to the brachial plexus (n = 293 elements)

Type of lesion

Neurolysis*

Suture**

Graft**

Lesions w/ complete loss (202 elements)

46/42 (91%)

21/14 (67%)

135/73 (54%)

Lesions w/ incomplete loss (91 elements)

82/78 (95%)

6/5 (83%)

3/2 (67%)

Total

128/120 (94%)

27/19 (70%)

138/75 (54%)

Results are given as the total number of elements/ the number of elements recovering to ≥ grade 3 by Louisiana State University Health Sciences Center Scale. * Neurolysis was based on the presence of an NAP across a lesion in continuity. ** Suture or graft repair was based on the absence of an NAP across a lesion in continuity. A few graft repairs were performed in lesions conducting an NAP in which split graft repairs were carried out. Reproduced with permissions from Kline and Hudson’s Nerve Injuries: operative results for major nerve injuries, entrapments and tumors, 2008)

Table 24.6  Overall postoperative functional grades in patients with 366 supraclavicular plexus stretch injuries

Initial loss of function

Postoperative grade

0 a

C5–6 C5–7

a

C5–T1 C5–8

a

a

1

1-2

2

2-3

3

3-4

4

4-5

Totals

1

0

0

0

6

14

18

9

7

55

1

0

0

2

14

23

20

9

6

75

21

8

15

29

62

40

20

13

0

208

0

0

0

0

0

1

1

0

0

2

C6–T1

a

0

0

0

1

0

2

1

0

0

4

C7–T1

a

0

0

0

0

1

1

0

0

0

2

C8–T1

a

2

3

2

2

0

2

0

0

0

11

C8–T1

b

0

0

0

0

0

0

2

2

3

7

C7–T1

b

0

0

0

0

0

1

1

0

0

2

25

11

17

34

83

84

63

33

16

366

Total a

Complete or nearly complete loss. Incomplete loss. Reproduced with permissions from Kline and Hudson’s Nerve Injuries: operative results for major nerve injuries, entrapments and tumors, 2008) b

(57%) or other more unusual patterns such as nerves at C8–T1 or C7–T1 (8%).8 Table 24.6 illustrates the overall postoperative grades at 18 or more months after surgery in 366 supraclavicular stretch injuries with various preoperative distributions where direct repair and limited nerve transfers were done. For clarity and to guide the treating physicians managing patients with stretch injuries to the BP, we have divided the clinical outcomes in operated cases into 3 categories based on the plexus elements that were afflicted and potential for useful functional recovery.8

Surgical results for C5 and C6 stretch injuries There were 55 patients in this category. All sustained complete loss in the C5–C6 distribution (no supra- or infraspinatus, and no deltoid, biceps, brachioradialis, or supinator function), and the loss persisted for 4 or more months prior to surgery in virtually all cases. Most (43 patients) of these patients who did not have avulsed nerve roots required graft repair with outflows from C5 and C6 to anterior and posterior divisions of the upper 359

Section Three  Adult brachial plexus palsies

Table 24.7  Outcomes of surgery for 55 stretch injuries to the C5 and C6 nerves with complete loss of function

Operation

No. of patients

Average outcome (no. of patients)

Grafts of C5 & C6 nerves

34

Grade 3 (19) Grade 3–4 (7) Grade 4 (8)

C5 nerve grafts, C6 nerve avulsed, descending cervical plexus used*

5

Grade 2–3

C5 nerve avulsed, C6 nerve grafts, descending cervical plexus used†

2

Grade 3–4

C5 and C6 neurolysis (NAPs present)

12

Grade 3–4

2

Grade 3–4

C5 neurolysis, C6 nerve grafts

* Patients who underwent these procedures might have done better had medial pectoral branch transfer to musculocutaneous nerve been added. † Patients who underwent these procedures might have done better had accessory nerve transfer to suprascapular nerve been added. Reproduced with permissions from Kline and Hudson’s Nerve Injuries: operative results for major nerve injuries, entrapments and tumors, 2008)

trunk. The results were generally very good in these 43 patients, with useful function obtained in the vast majority. For instance, 9 patients recovered to grade 3, 8 patients to grade 4, and 7 patients to grade 3 to 4. Patients with avulsed nerve roots underwent direct repair from the non-avulsed roots to anterior and/or posterior divisions of the upper trunks supplemented with nerve transfers, with the objective of restoring shoulder and elbow function (see below). Finally, there were 12 cases in which both C5 and C6 spinal nerves had recordable NAPs, despite being 4 to 8 months after injury with complete clinical and EMG loss. These patients underwent neurolysis alone, and recovered to grade 3 to 4 (Table 24.7). Although results were generally good with C5–C6 stretch repairs, recovery was not uniform in this distribution. Forearm flexion was almost always better than shoulder abduction. The latter was seldom good enough to raise the shoulder above horizontal. Thus, it remains important to identify patients with early spontaneous recovery 360

and spare them from surgery (Table 24.7). Results may have been better had additional transfers been done. Summary of results of surgery for C5 and C6 lesions. (1) Distribution of loss is very predictable: supraand infraspinatus, deltoid, biceps/brachialis, brachioradialis, and supinator. (2) Almost 30% show signs of spontaneous recovery by 3 to 4 months after injury. (3) Despite apparent clinical and (preoperative) electrical sparing, C7 may be found to be seriously involved at operation in 15% of cases. If C7 is resected because of an absent NAP in this setting, postoperative loss is not increased and yet C7 can be used to supplement the repair. (4) This is the most favorable group of serious stretch injuries to repair with direct nerve grafts. (5) Direct repair of one or both spinal nerves is likely. Supplementation with neurotization, especially spinal accessory to suprascapular and medial pectoral or ulnar fasicle(s) to musculocutaneous may be beneficial in restoring arm abduction and elbow flexion.

Surgical results for C5, C6, and C7 stretch injuries This group of patients not only had a C5–C6 pattern of loss, but had some weakness of triceps, wrist, and sometimes finger extension. Loss of wrist and finger extension and weakness of the flexor profundi muscle varied because of dominant input of the C8 nerve to these muscles in some patients. There were 75 patients in this group who were selected for surgical exploration and repair because they suffered complete or persistent severe clinical loss, at least in the C5–C6 distribution. Most of the C5, C6, and C7 stretch injuries selected for operation required graft repairs. There were, however, important exceptions, based on intraoperative NAP studies that supported regeneration or nerve root avulsion. If 2 of the 3 involved roots could have a neurolysis based on a positive NAP despite complete clinical and electrical loss, results were also predictably good. Where only one spinal nerve had a neurolysis, average recovery in that spinal nerve distribution was grade 3 to 4. Overall, slightly less than 25% of surgical patients in this category had neurolysis, not only because of physical continuity of the stretched elements, but because of present (regenerative) NAPs. This was despite the fact that loss clinically and electrically in their distribution was complete. These patients

Outcomes of treatment for adult brachial plexus injuries

Table 24.8  Outcomes of surgery for 75 stretch injuries to the C5-C7 nerves with complete loss of function

Operation

No. of patients

Average outcome

Grafts of C5, C6, & C7 nerves

31

Grade 3–4

C5 nerve grafts, C6 & C7 nerves avulsed, descending cervical plexus used*

10

Grade 2–3

C5 and C6 nerve grafts, C7 nerve avulsed, descending cervical plexus used

10

Grade 3

C5 nerve avulsed, C6 & C7 nerve grafts, descending cervical plexus used†

6

Grade 3–4

C5, C6, & C7 neurolysis (NAPs present)

18

Grade 4

* Patients who underwent these procedures might have done better had medial pectoral branch transfer to musculocutaneous nerve been added. † Patients who underwent these procedures might have done better had accessory nerve transfer to suprascapular nerve been added. Reproduced with permissions from Kline and Hudson’s Nerve Injuries: operative results for major nerve injuries, entrapments and tumors, 2008).

had very good outcomes, achieving grade 4 overall results (Table 24.8). The second factor playing a significant role in the outcome of these cases was the presence of avulsion injury extending to the level of the dura. This usually affected 1 root (16 instances). However, in 10 cases, such injury affected 2 roots. As a result, in 26 cases, nerve repair was performed with grafts from only 1 or 2 proximal spinal nerves. Grafts were not only led distally to where the root normally innervated, but also to adjacent outflows in which proximal counterparts had been avulsed. These direct repairs were supplemented with by use of descending cervical plexus. For instance, in 10 cases of isolated C7 avulsions, direct graft repairs from C5 and C6 nerves to the anterior and posterior divisions of the upper and middle trunks resulted in an average recovery of grade 3. Recovery in an avulsed root’s distribution by transfer of grafts from other roots ranged from grade 1 to 4, but averaged at grade 2 to 3. Thus, avulsive root injuries usually lowered the overall grades for repair of C5, C6, and C7 injuries (Table 24.8). Results may have been better had additional transfers been done.

24

Summary of results of surgery for C5, C6, C7 lesions. (1) Loss involves triceps in addition to shoulder muscles, biceps/brachialis, brachioradialis, and supinator. Loss of finger extension, flexor profundi, and wrist extension is variable, because C8 input to these muscles is dominant in some patients. (2) A few cases of serious C5, C6, C7 injury (16%) improve spontaneously in the early months after injury. (3) Despite sparing of C8–T1 muscle function, opportunities for effective substitutive procedures are limited. For example, it is difficult to substitute for loss of shoulder and upper arm function. As a result, operation to attempt direct repair of the plexus with or without the addition of neurotization is usually indicated. (4) The incidence of root avulsions is much higher in this group than with C5–C6 stretch injuries. (5) In circumstances when only neurolysis is required, or 2–3 spinal nerves are available for direct graft, the outcomes are very satisfactory. (6) Direct repair of only one element frequently needs to be supplemented by neurotization. (7) Outcome is usually best for biceps/brachialis, but imperfect return there can be affected adversely by partial recovery of triceps. Supraspinatus recovery is usually better than that for deltoid.

Surgical results for C5–T1 stretch injuries This group represents the most common stretch injury and was seen in 208 patients (57%). The presenting and usually persistent symptom was total upper extremity paralysis or flail arm. This group of patients had the lowest spontaneous recovery rate (4%). Criteria used to select these C5–T1 stretches for operation included preservation of rhomboid, serratus anterior, and diaphragmatic function. Patients with a meningocele of C4–C5, cervical myelopathy, overwhelming medical problems, or who were evaluated by us a year or more after injury were excluded. Not unexpectedly, approximately half of the spinal nerves or roots evaluated at the operating table had proximal irreparable damage or were avulsed at the dural level. This was despite the fact that some attempt was made to select the more favorable patients for operation and to visualize the root or spinal nerve as close to the dural level as possible in these patients. On the other hand, despite this large number of avulsed and irreparable spinal nerves, an almost equal number were reparable or, in some instances, had a regenerative NAP. Evidence of regeneration 361

Section Three  Adult brachial plexus palsies

or reparability due to a more lateral lesion was most frequent for C5 and/or occasionally C6 or even C7. There were 1,040 spinal nerves evaluated in 208 patients, both preoperatively and at the operating table. Despite attempts to select favorable cases for repair, 470 elements had irreparable proximal damage, usually due to avulsion: 35% at the C7–C8 level, 35% at the C7–T1 level, and only 10% at the C5 level. Direct graft repairs were performed on the remaining 570 spinal nerves. Graft repair of 2 spinal nerves per patient was performed in 54 cases, and 3 or more spinal nerves per patient were repaired in 76 cases. Because regenerative NAPs were measured distal to their lesions, 35 of the patients required only neurolysis without graft repairs on one or more plexus elements. Nine patients underwent split graft repair of the C5 or C6 nerve and its outflows. The C5–T1 lesions or flail arms were especially difficult to manage effectively. Restoration of function was often quite limited, even after an attempt was made to select patients for their operability. Although some restoration of shoulder abduction and flexion of the elbow was obtained in approximately 40% of cases and some triceps function in 30%, these operations were often salvage-like in nature. Useful wrist or finger motion was seldom obtained. Most of the better functional grades were due to shoulder and upper arm recovery rather than distal function. In the few exceptions, presence of not only continuity but a non-preganglionic and regenerative NAP led to neurolysis of one or more lower elements and, because of spontaneous regeneration, some subsequent degree of useful recovery of hand function occurred. A large subgroup of injuries had reparable or regenerating C5 and C6 roots despite proximal avulsions of C7, C8, and T1 roots. In summary of all 31 patients regardless of length of follow-up, average recovery in the C5 distribution was grade 2.2. Recovery averaged grade 2.3 in the C6 distribution and only grade 1.4 in the C7 distribution. However, after follow-up of 30 months and more, average C5 recovery was grade 2.7, C6 recovered to grade 2.9, and C7 to grade 1.6. The largest subset of C5–T1 stretch injury patients receiving surgery were those with either regenerating or reparable C5, C6, and C7 nerve roots found at the operating table. In these 34 cases, C8 and T1 were not reparable, but C5 recovery averaged grade 2.4, C6 was grade 2.7, and C7 was grade 1.9. In this category of patients who had 24 or more months of follow-up, C5 362

averaged grade 2.6, C6 was grade 2.9, and C7 remained grade 1.9. As can be seen in Table 24.6, only about a third of all C5–T1 stretch injury patients gained an overall grade of 3 or better outcome. As a result, in the last few years, most patients with C5–T1 stretch injuries or flail arms have undergone more robust neurotization (nerve transfers) in addition to any direct graft repairs. These transfers usually required accessory nerve to suprascapular nerve or posterior division of upper trunk and intercostal nerves to musculocutaneous nerve. As a result, grades for shoulder and biceps muscles have increased by an average of 0.85 (see below). It should be stressed that if iNAP recordings are used in evaluating supraclavicular stretch injuries, there are 5 possible situations: (1) a normal iNAP for an intact element; (2) a near-normal iNAP or a fast iNAP and one that transmits far distal to where regeneration could have been expected to reach for a preganglionic lesion; (3) A small, slowly conducting regenerative NAP; (4) a flat trace associated with a lateral neurotmetic lesion or a combined pre- and postganglionic lesion. Summary of results of surgery for C5, C6, C7, C8, and T1 lesions. (1) This most frequent pattern of loss due to stretch seen in this series of patients unfortunately produces a totally paralyzed or flail arm. (2) The incidence of spontaneous recovery of function is the lowest (only about 4%) for all patterns of severe stretch injury. (3) A combination of severe paraspinal denervation, positive sensory NAPs from several nerves, or meningoceles at 3 or more levels (especially if upper levels are involved), stands against success with attempted direct repair. (4) These patients are difficult to help by either direct repair and/or neurotization, and these operations are often only salvage-like in nature. (5) About one-third of patients obtain useful recovery by direct repair. Selective nerve transfers appear to improve outcomes for shoulder and elbow function in an additional number of patients. A combination of direct repair supplemented by nerve transfer appears to give the best outcome for nerve recovery.

Surgical complications for bp stretch/ contusion injuries Due to the complexity of BP stretch injuries, the distorted anatomy, and extensive scar tissue, many complications can be encountered. In our series,

Outcomes of treatment for adult brachial plexus injuries

these included phrenic paralysis, which in most instances reversed in time but did persist beyond one year in 3 cases. Some experienced postoperative pneumothorax requiring placement of a chest tube postoperatively, and some patients needed thoracocentesis. Wound infections did occur, but none were deep and none required irrigation and debridement. Several seromas were aspirated in the early postoperative period and fortunately did not recur. Two patients required serial aspirations of collections of lymph, but the wounds subsequently healed with the help of compressive dressings. Two patients collected cerebrospinal fluid at their wound sites, and these resolved by recurrent local aspiration and compressive dressing. In the earlier years of this series, the clavicle was sometimes divided. Despite fixation, malunion occurred in several instances. In the last 20 years, the clavicle has been cleared of soft tissues, encircled by sponges, and drawn up superiorly and then down inferiorly to complete the necessary dissection of plexus beneath it. Bleeding from the vertebral artery at a foraminal level led to its surgical occlusion in 5 cases; in other instances bleeding was stopped by the use of bipolar forceps and Oxycel cotton. Vertebral occlusion, if necessary, was usually tolerated well. In one case, vertebral occlusion led to a delayed cerebellar and brainstem stroke in a patient who had undergone prior treatment of an ipsilateral carotid cavernous fistula by a balloon technique, and the internal carotid had subsequently occluded.

Results of direct plexus element repairs supplemented with nerve transfers In recent years, we began to supplement direct BP element repairs with nerve transfers. Recent analysis of the results of this operative strategy shows a trend towards better functional outcome in this group of patients. A major advantage of nerve transfer as compared to nerve grafting or primary repair is the ability to convert a proximal high-level nerve injury to a low-level nerve injury.14,16,17,18,19 Donor nerves are selected based on proximity to the motor end-plates, and the repair is performed without tension or grafts whenever feasible.19,20 The primary functional goals of nerve transfer techniques are restoration of elbow flexion and shoulder abduction.20,21

24

In an attempt to restore elbow flexion, we employed 2 types of nerve transfers to the musculocutaneous nerve, namely, medial pectoral and intercostal nerves with 56 and 18 patients in each group, respectively. With regard to elbow flexion, 90% of patients in our series recovered to LSUHSC grade 2 and 60% to LSUHSC grade 3 after a mean follow-up period of 3.5 years. Return of elbow flexion in our 18 patients who had intercostal to musculocutaneous nerve transfers showed that about 60% of the patients recovered to LSUHSC grade 2 over the follow-up period, but only 22% recovered to LSUHSC grade 3 as opposed to 60% after medial pectoral to musculocutaneous nerve transfers. Of course, medical pectoral transfers can only be used in patients with S5, T1 sparing. Overall, recovery of elbow flexion to M3 can be expected in 60% of patients after intercostal to musculocutaneus nerve transfers and 90% of patients after medial pectoral to musculocutaneous nerve transfers.22 We believe our results are slightly better than some other reported series because we performed direct repair of the plexus elements in addition to nerve transfers. The addition of direct proximal plexus element repair may also explain the significantly better results (90% recovery of useful elbow flexion) obtained with medial pectoral nerve transfer, which represents an intraplexal type of nerve transfer as compared to the intercostal, which is extraplexal. In other words, concordant reinnervation of the denervated muscles by plexus-derived axons (from direct repair and nerve transfer) may have provided a better regenerative environment than a mixture of extraplexal (intercostal nerve transfer) and direct repair.21,23,24 For restoration of shoulder abduction, we used spinal accessory to suprascapular nerve transfer in 57 patients. Recovery of supra- and infraspinatus muscle function varies significantly, with 95% of patients recovering grade 2 supraspinatus muscle strength and only 50% of patients achieving the same level of strength in the infraspinatus muscle. Furthermore, 77% of patients recovered to LSUHSC grade 3 of supraspinatus, but only 21% of patients regained a grade 3 of infraspinatus muscle strength.22 The reason for this discrepancy in the recoverability of supra- and infraspinatus is unclear. There were 8 patients who had thoracodorsal-to-axillary nerve transfers, and recovery to LSUHSC grade 2 was achieved in 36% of patients; only 25% of patients recovered to LSUHSC grade 3 in our series. These results are not as robust as for other nerve transfers. 363

Section Three  Adult brachial plexus palsies

Conclusions Significant advances have been made in microsurgical management of the injured BP, as this chapter attests. However, restoration of fully functional upper extremities in patients who have sustained a BP injury is still suboptimal, especially for those patients with pan-plexus injuries. Nerve transfer techniques offer alternatives to nerve repair strategies for plexus injuries, either as a stand-alone technique or as a supplement to direct repair of plexus elements (Tables 24.9A and 24.9B).

Clinical observations and animal experimentation have identified time and distance as 2 major factors that contribute to poor functional recovery.3,4,5,25 In essence, there seems to be a limited time window of opportunity when support for regenerating axons is optimal and the potential for functional recovery is maximal, but the slow rate of axonal regeneration (1–3  mm/d) after injury results in delayed reinnervation of Schwann cells of the distal nerve stumps and deprives the regenerating neurons of access to neurotrophic support.3,4,5 Hence, Schwann cells become chronically denervated, and the neurons are chronically

Table 24.9A  Repair preferences for C5/C6 stretch or C5/C6/C7 stretch injuries

Intraoperative findings

Recommended procedure

Comments

Positive NAPs (not caused by preganglionic injury)

Neurolysis

Positive NAPs indicate regeneration

Flat NAPs + good proximal fascicular structure on sectioning spinal nerve

Direct repair plus addition of medial pectoral to split musculocutaneous nerve (for C6 avulsion) or accessory to suprascapular nerve (for C5 avulsion)

NAP studies indicate preganglionic lesion, or sectioning indicates pre- and postganglionic lesions of C5 and C6.

Spinal accessory and medial pectoral transfers and, less frequently, descending cervical plexus transfers.

An alternative to MP to musculocutaneous transfer is the Oberlin transfer (ulnar to musculocutaneous transfer).

NAP = nerve action potential

Table 24.9B  Repair preferences for C5–T1 stretch injuries or flail arm

Intraoperative findings

Recommended procedure

Comments

Positive NAPS (not due to preganglionic injury)

Neurolysis

This finding is infrequent but does occur.

Negative NAPs but fascicular structure is found proximally

Direct graft repair and (a) accessory to suprascapular nerve; (b) descending cervical plexus to posterior division of upper trunk or middle trunk and its divisions; (c) intercostals (3 or 4) to a longitudinally split portion of musculocutaneous nerve.

Grafts are from proximal spinal nerves to divisions or cords.

All 5 plexus roots avulsed

Nerve transfers options: (a) accessory nerve to suprascapular, (b) intercostal nerves to musculocutaneous nerve, and (c) either descending cervical plexus or accessory nerve input to sternocleidomastoid muscle placed to posterior division of upper trunk.

NAP = nerve action potential From Kim D, Midha R, Murovic J, Spinner R: Kline & Hudson’s Nerve Injuries: Operative Results for Major Nerve Injuries, Entrapments, and Tumors. 2nd edition, Elsevier 2008

364

Outcomes of treatment for adult brachial plexus injuries

axotomized, which results in reduced regenerative capacity and functional recovery. The proven added benefits of nerve transfers underscore the roles that distance and time play in the regenerative capacity of injured nerves. Timing of the window of opportunity for optimal regenerative support and subsequent functional recovery is known to be between 1 to 8 weeks in rat experiments3 and has been suggested to be 12 to 18 months for humans.20 Therefore, further research into other clinically applicable means of optimizing axonal regeneration during the limited time window may go a long way toward improving functional outcome in patients with BP injuries.12,26,27

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