Surgical Therapy
Primary exploration of the brachial plexus is performed if any of the following conditions are evident: (1) global injury that does not improve by 3 months of age, (2) lack of motor function of 1 or more muscles (elbow flexors, shoulder abductors and external rotators, and wrist and finger flexors) at 3-6 months, or (3) extremity-muscle units with no progress at 6 months or beyond.
Primary repair of the brachial plexus is a combined procedure involving a neurosurgeon, pediatric plastic surgeon, and a pediatric neurologist performing intraoperative EMG. Depending on the injury, neuroma excision and sural interpositional nerve grafting (or neurotization in patients with avulsion) are performed.
A supraclavicular approach to the proximal brachial plexus is made through standard lateral sternocleidomastoid incision. The omohyoid is often divided. The phrenic nerve is identified and stimulated to assess diaphragmatic function. Electrophysiologic tests are performed, and proximal evoked potentials are measured by stimulating exposed nerve roots.
A conducting neuroma-in-continuity is not excised if the decrease in amplitude across the lesion is less than 50%. The surgeon performs neurolysis with fascicular grafts across the neuroma to enhance the conduction of nerve signals. C4 sensory and great auricular nerves are usually harvested. The sural nerve can also serve as a conduit. The coaptations are all performed in a tension-free fashion with 9.0 or 10.0 nylon microsuture.
When the neuroma results in poor conduction on electrophysiologic studies (>50% decrease in signal amplitude across the lesion) and when the gross appearance suggests excessive scarring, the neuroma is carefully excised. C5 and C6 lesions are the most common lesions, followed by C5, C6, and C7, and C5-T1 lesions. Isolated C8 and T1 lesions are the least common injuries. Electrophysiologic testing helps in identifying proximal donor nerves for grafting. C5 and C6 are important as donor proximal nerves to graft across the resected neuroma.
Other surgeons graft as distally as possible to the terminal cord or the end of the distal nerve. Terzis prefers to use intraplexus vascularized grafts, such as the ulnar nerve, to bridge long gaps in the reconstruction of the brachial plexus with avulsion injuries of C8 and T1. [15]
For severe avulsions involving the upper trunk, or, less commonly, the lower trunk, neurotization from the intercostal, accessory, phrenic, contralateral C7, or pectoral nerves can be used. [4]
A study by Morrow et al found that following primary nerve reconstruction to reinnervate the lower trunk in patients with complete brachial plexus birth injury, 81% had, by age 8 years, experienced enough hand function improvement “to sufficiently perform bimanual activity tasks.” Mean age of surgery was 4.1 months. [16]
Secondary reconstruction
Secondary deformities may arise from incomplete recovery after nonsurgical management or from incomplete recovery or residual dysfunction after primary reconstructions. These deformities pertain to muscular imbalances and to persistent nerve deficits that produce the posture of internal rotation and adduction of the shoulder. This posture triggers contracture formation of the subscapularis and pectoralis major and minor muscles. The muscular imbalance stimulates posterior dislocation or subluxation of the glenohumeral joint.
The surgeon considers secondary intervention when rehabilitative therapy plateaus. This is usually when the patient is 18 months of age. The surgical procedure is tailored to the patient depending on his or her deficits and limitations.
In the secondary procedure, the axilla is entered through an L -shaped, or hockey-stick, incision. The latissimus dorsi and its pedicle are identified and dissected. The subscapularis space is entered while the thoracodorsal and long thoracic nerves and the nerve to the teres major are protected. The subscapularis muscle is released along the inferior border with extraperiosteal elevation up to the glenoid fossa.
In certain cases, myotenotomy of the pectoralis major near the humeral insertion is executed if restriction or capsular contracture is present. The myotenotomy is executed near the humeral insertion in the anterior aspect of the axillary fossa through several small, partial-thickness incisions to keep the muscle in continuity. After the contracture is released, the surgeon should test the shoulder range of motion to ensure the absence of residual contracture.
The quadrangular space is then entered to find the axillary nerve, and it is stimulated with a nerve stimulator. If the degree of deltoid contraction is diminished, neurolysis along the entire nerve is carried out until the muscular response or contracture increases in response to the electrical stimulus. If the deltoid contracture is absent or severely diminished, nerve transfer or neuroplasty with branches of either the thoracodorsal nerve or the nerve to teres major is achieved.
Finally, the latissimus dorsi and teres major are disinserted from their insertions on the humerus. They are anchored and transferred to the tendon of the teres minor to aggrandize and promote shoulder external rotation.
Each patient is splinted in shoulder abduction, full external rotation, and full elbow extension for 4-6 weeks. Physical therapy is then started.
Additional procedures
The shoulder and elbow should be treated before the forearm, wrist, and hand. Rehabilitation and continuous physical therapy are essential for recovery and muscle strengthening. Many patients require augmentation procedures to enhance nerve transfers and/or tendon transfers to manage avulsions of the upper roots and loss of the critical biceps function. Partial triceps transfers or triceps lengthening may augment arm function. Transfer of the latissimus dorsi muscle to augment biceps functions has also been used, with excellent results. The surgeon may also use selective nerve transfers to restore function of individual muscles. End-to-side radial sensory to median nerve transfer has been reported to improve sensation and to relieve pain in C5 and C6 nerve root avulsion. [17]
When severe avulsion injuries to the lower roots occur with no return of hand function, many reconstructive options are available (see the Table).
Table. Surgical Treatments and Secondary Procedures (Open Table in a new window)
Condition or Deficit |
Surgical Treatment and Secondary Procedures |
Internal rotation, shoulder adduction |
Muscle releases: subscapularis, pectoralis major and minor Muscle transfers to the teres minor: latissimus dorsi, teres major Neurolysis and decompression of the axillary nerve |
Poor elbow extension |
Nerve exploration and neuroplasty of the radial nerve with or without tendon transfers |
Poor extension of the wrist and digits |
Muscle transfers
|
Poor extension of the wrist and fingers if flexors are weak |
Musculocutaneous nerve transfer Placation or tenodesis of the extensor digitorum communis Wrist fusion and tendon transfers Free muscle transfer |
Poor elbow flexion, poor supination |
Exploration and neuroplasty of the radial and musculocutaneous nerves with or without nerve transfers Oberlin technique Double nerve transfer Fascicular transfers
|
Elbow flexion contracture |
Lengthening of the biceps if serial casting is unsuccessful [18] |
Poor flexion of the wrist and fingers |
Nerve exploration and neuroplasty of the median and order nerves Once muscle transfer |
Forearm supination contracture |
Rerouting of the biceps Rerouting of the supinator |
Forearm pronation contracture |
Rerouting of the pronator teres |
Microsurgical free muscle transplantation with muscles such as the gracilis is used to restore finger and thumb flexion and extension when tendon transfer is impossible or ineffective. [19]
When all other options are exhausted, palliative tenodesis of the wrist extensors and wrist and interphalangeal arthrodesis may need to be considered.
Postoperative Details
Patients are admitted for a mean stay of 2 days. During this time, the patient is monitored and the drain is removed on the second postoperative day. The therapist designs an orthoplastic splint to maintain the shoulder with sufficient abduction and external rotation.
Complications
Surgical complications occur relatively infrequently and include wound infection, hematoma, and seroma. Depending on the severity of the original injury, various degrees of functional improvement can be expected.
Future and Controversies
Early intervention can be preventive in some patients with obstetrical brachial plexus palsy. Prompt evaluation and management revolves around diligent education of both pediatricians and parents. The creation of multidisciplinary centers has greatly improved treatment outcomes in patients with brachial plexus palsy. A wide array of primary and secondary procedures has evolved to combat the sine que non and deficits of brachial plexus palsy.
Tables
Condition or Deficit |
Surgical Treatment and Secondary Procedures |
Internal rotation, shoulder adduction |
Muscle releases: subscapularis, pectoralis major and minor Muscle transfers to the teres minor: latissimus dorsi, teres major Neurolysis and decompression of the axillary nerve |
Poor elbow extension |
Nerve exploration and neuroplasty of the radial nerve with or without tendon transfers |
Poor extension of the wrist and digits |
Muscle transfers
|
Poor extension of the wrist and fingers if flexors are weak |
Musculocutaneous nerve transfer Placation or tenodesis of the extensor digitorum communis Wrist fusion and tendon transfers Free muscle transfer |
Poor elbow flexion, poor supination |
Exploration and neuroplasty of the radial and musculocutaneous nerves with or without nerve transfers Oberlin technique Double nerve transfer Fascicular transfers
|
Elbow flexion contracture |
Lengthening of the biceps if serial casting is unsuccessful [18] |
Poor flexion of the wrist and fingers |
Nerve exploration and neuroplasty of the median and order nerves Once muscle transfer |
Forearm supination contracture |
Rerouting of the biceps Rerouting of the supinator |
Forearm pronation contracture |
Rerouting of the pronator teres |
