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Obstetric brachial plexus injury (OBPI) is rare. It occurs with an incidence of 0.1% to 0.4% of live births.1,2 Included in this incidence rate are minor birth palsies that spontaneously recover fully within the first 2 months of life. Obstetrical risk factors include prolonged labor, difficult delivery, fetal distress, breech position, shoulder dystocia, cephalopelvic disproportion, and high birth weight.3 During a difficult vertex delivery, traction forces are often applied to the brachial plexus when one shoulder is trapped behind the pubic symphysis and is freed by lateral flexion of the neck when the trunk is pulled. Difficult arm extraction in a breech delivery can result in an avulsion injury related to distraction forces on the brachial plexus when the head is delivered with strong lateral flexion of the neck by pulling the trunk. Direct contusion of the brachial plexus can also occur by contact of the forceps. Anatomical variations, such as cervical ribs or fibrous bands, can cause narrowing of the supracostoclavicular space and render the adjacent nerves more susceptible to external trauma.4 The degree of disability is related to the level and magnitude of injury to the brachial plexus. Degree of neural injury can be classified by type of injury (stretch, rupture, avulsion) and severity of injury. The severity of the neural injury determines the extent of motor and sensory loss. The most severe injuries are avulsions of the nerve roots.3 Current preventive measures and advanced quality of obstetrical care have served to decrease the severity and extent of paralysis.
OBPI is classified according to the components of the plexus that are injured and is grouped into three main types. Upper arm type (Erb Duchenne) involves injury to the upper trunk at the junction of the fifth and sixth nerve roots. Lower arm paralysis of Klumpke refers to paralysis of the eighth cervical and first thoracic nerve roots. Paralysis of the entire arm involves injury to all components of the brachial plexus. Understanding the normal anatomy of the brachial plexus is important because it supplies every muscle of the upper extremity with the exception of the trapezius. As a review of brachial plexus anatomy, C5 and C6 roots join to form the upper trunk. The C7 root becomes the middle trunk, and the C8 and T1 roots become the lower trunk. Each trunk has an anterior and posterior division. The anterior divisions of the upper and middle trunks form the anterior cord. The posterior divisions of all three trunks form the posterior cord. The anterior division of the lower trunk continues as the medial cord. The terminal branches of the cords form the major nerves for the upper extremity. With OPBI, any of these nerves can be affected. Most infants have involvement of the upper trunk (C5–6), Erb’s palsy. The most common injury is postganglionic rupture of the upper trunk.3
Many infants with OBPI recover normal function spontaneously. This generally occurs within the first 2 months of life. Prognosis by natural history has been best defined by the spontaneous recovery of muscle strength in the first 3 to 6 months of infancy.3 Permanent injury can result and is most common in infants who do not begin to experience recovery within the first 6 months of life. Gilbert and Tassain5 describe the recovery of biceps function in infancy as a predictor of the outcome of spontaneous recovery. Waters6 contributes to this outcome prediction method by showing that infants who do not recover biceps function by 3 months of life will not exhibit normal function after 2 years of age. However, this method of prediction of recovery carries a 12% error rate.7 As a method of decreasing this error rate, the Toronto scale is used, which includes measurement of return of elbow flexors and extensors, wrist extensors, finger extensors, and thumb extensors. This decreases the error rate to 5%.3 Thus, the indications for microsurgery include absence of biceps recovery, Toronto score of less than 3.5, and total plexopathy with Horner syndrome.
Children with chronic upper trunk plexopathy may go on to experience external rotation weakness and internal rotation contractures about the shoulder. This muscle imbalance can alter the structure of the glenohumeral joint. There can be incongruence of the joint with definite anatomical changes. The glenoid fossa becomes broad and flattened. This glenoid flattening is proportional to the lack of active muscle activity necessary to stimulate normal development of the joint structure. With persistent internally rotated and adducted position of the shoulder, and fixed contracture of the subscapularis and pectoralis, the humeral head tends to displace posteriorly. The posterior lip of the glenohumeral joint becomes hypoplastic, allowing further posterior displacement. Bony deformities include an elongated coracoid process whereby it hooks downward and laterally and pushes the humeral head posteriorly. The scapula becomes smaller and higher in position. These bony deformities of the acromion and coracoid process further limit external rotation and extension of the shoulder. Function, especially with the arm in above-head horizontal activities, is impaired. In young children with nearly normal glenohumeral joints, the modified L’Episcopo procedure—involving anterior release of the pectoralis major, subscapularis lengthening and transfer of the latissimus dorsi and teres major to the rotator cuff—improves function.8,9 The muscle balance that this transfer restores equalizes the forces on the shoulder and carries the secondary benefit of potentially restoring normal anatomy, preventing progressive glenohumeral joint deformity, and permitting glenohumeral joint remodeling.3
PREOPERATIVE CLINICAL PICTURE
Before surgery, the most commonly seen clinical picture includes the shoulder in an adducted and internally rotated position. The elbow tends to remain slightly flexed with the forearm held in pronation. Often there is spontaneous use of the hand, and the child may have the ability to grasp and release objects. Abduction and external rotation contracture also may be seen because of inferior subluxation or dislocation of the glenohumeral joint. This is related to contracture of the denervated supraspinatus, infraspinatus, and teres minor, as well as changes in glenoid morphology. Paralysis of the supraspinatus, infraspinatus, teres minor, and posterior and middle deltoid is paired with normal function of the antagonistic muscles. The pectoralis major, subscapularis, teres major, and latissimus dorsi all function normally, thereby overpowering the denervated muscles. With abduction and external rotation contracture, there is winging of the scapula with the arm positioned at the side. The glenohumeral joint is markedly limited in range of motion in abduction/adduction and external rotation. Limited abduction, external rotation, and extension of the shoulder make it difficult for the patient to bring the hand to the top of the head or the back of the neck.
Surgical management for these children uses a modified L’Episcopo procedure that requires two incisions. The first is an anterior incision in the deltopectoral interval in the shoulder. This allows exposure of the pectoralis major tendon on the proximal humerus, which is typically tight, limiting external rotation and abduction of the arm. This tendon is released from the humerus. The next deeper layer is subscapularis, part of the anterior capsule of the shoulder. This is Z lengthened to allow for increased external rotation while also maintaining the integrity of the anterior shoulder and preventing instability. Next the latissimus dorsi and teres major tendons that pass inferior to the humeral head, from posterior to anterior, and are conjoined at their insertion on the anterior humerus, are identified and tagged with suture. They are then released, passed posteriorly, and reinserted on the posterolateral aspect of the rotator cuff. This changes their action from internal rotators and extenders of the shoulder to external rotators and abductor/flexors of the shoulder. This is done with the arm in maximal abduction and external rotation (ball throwing position), which will be held after surgery by the orthosis. The wounds are then closed and the arm immobilized for 6 weeks full time, followed by nocturnal immobilization only.
PREOPERATIVE MEASUREMENT/MOLDING PROCESS
Before surgery, the functional limitations of these children may preclude an ideal opportunity to measure or mold secondary to range-of-motion limitations. The inability to position the child in the anticipated improved postoperative position may decrease the accuracy of the final fit of the orthosis. Thus, it is necessary to include in the design a method for adjusting the amount of both abduction and external rotation. The outcome of the procedure may dictate the ability to brace the child in, what is predicted to be, a significantly improved position. Our experience has been that preoperative molding is the most appropriate method of ensuring an accurate postoperative fit. Our patient population has ranged in age from 18 months to 29 months, with the mean age being 24.7 months. This translates as our first orthotic challenge. The ability of a child this age to allow an intricate mold to be done is entirely dependent on the child’s tolerance and patience level. This, in turn, may be complicated by an aversion to the hospital environment secondary to multiple visits or previous negative experiences.
Of the four cases presented, all were molded at a preoperative visit and then fit under anesthesia immediately before the surgical procedure. The first two patients were placed in shoulder spica plaster casts immediately after the surgery; final fit with the custom orthosis was done 6 weeks after surgery, after cast removal. With successful positional outcome of the first two cases using the custom orthosis, the second two cases were placed immediately into the custom orthosis, eliminating the need for the plaster cast. Immediate postoperative fitting with the child anesthetized allowed increased cooperation, increased relaxation of the muscles, and more accurate positioning.
In all four cases, molds were taken before surgery of the child’s arm with the elbow flexed to 90° and the shoulder externally rotated to accurately reflect the humeral shape. The wrist was included in the mold; however, the fingers and thumb were left free. The forearm and wrist were molded in a functional position. The material used for molding was flexible fiberglass, which allowed delayed removal without a cast saw. With the arm mold still in place, the torso was addressed. The torso mold was taken with the patient in a standing position. Waist creases were molded in on both sides for orientation, although the design of the orthosis included only one waist crease on the affected side. The mold was extended over the anterior superior iliac spine and as high into the axilla as anatomically feasible. With both separate torso and arm molds in place, the child was placed supine on a piece of tracing paper, and the relationship between the arm and the torso was drawn. The arm, with the child lying supine on the tracing paper, was positioned as abducted and externally rotated as range-of-motion limitations allowed. Measurements were taken for length of elbow to axilla and axilla to waist. The child was then moved to a sitting position, the lubricated cutting tube removed, and the arm mold snipped with blunt-edge scissors and then removed. The torso mold was marked for midline and removed in a similar fashion.
All of the orthoses used on the four children were custom molded because of the intimate fitting required to match the size of an 18- to 29-month-old child. The use of prefabricated shoulder abduction-rotation designs is also feasible; however, until recently they were not commercially available. Prefabricated designs are limited by the inability to scale down to the size needed for a child as young as 18 months. The custom design presented includes a molded copolymer torso and arm section. The arm component can be fabricated with a solid elbow (standard) or an articulated elbow, depending on the presence of contracture at the elbow (Figure 1). The upper extremity component extends over the wrist to place the forearm and wrist in a functional position. The fingers and thumb are left free. The torso section of the orthosis includes a midtorso trim line with accentuation of the waist crease and inferior flaring below the waist crease. Two Dacron torso straps secure the shell and extend across the body with Velcro closures. Adjustable position pads are attached to disperse pressure and facilitate a secure position of the orthosis because movement of the torso component of the orthosis away from the torso results in decreased relative abduction. Both copolymer components are padded and ventilated. A modified housing is positioned on the cast and vacuum formed into the plastic on both the torso and the arm section (Figure 2). The position of the housing on the arm component is on the posterior surface of the humerus, and the position of the housing on the torso is on the medial aspect of the torso. This housing is sized to accept a tubular aluminum bar stock at both ends that is secured into each housing with two Allen wrench set screws. (The housing used was a modified cut-down twister cable attachment from Becker Orthopaedic [Troy, MI].) Design of the orthosis must take into account that differences from pre- to postoperative position and range of motion require that the orthosis accommodate adjustment of both abduction and rotation. Interchangeable aluminum rods of variable lengths were fabricated to facilitate increases in abduction if needed. Adjustment for increases in rotation are simply made by loosening the set-screw on the humeral section and rotating the arm component around the bar stock. The shoulder is positioned in approximately 100° abduction and maximal external rotation (usually, 90°–100°; Figure 3). A shoulder strap is added across the contralateral shoulder to decrease migration of the orthosis and assist with balance (Figure 4).
POSTOPERATIVE MANAGEMENT PROTOCOL
The postoperative protocol for the first two cases (AA, MC) included 6 and 8 weeks, respectively, of immediate postoperative shoulder spica casting. After 6 weeks, the cast was removed. Clinically there was a marked increase of range of motion. The most significant increases in range of motion were seen in shoulder external rotation and shoulder abduction. At the time of cast removal and orthosis fitting, there was evidence of active shoulder abduction, flexion, and external rotation. Both children were able to functionally bring the hand to the back of the head, as well as perform an overhand throw (Figure 5). The custom shoulder abduction rotation orthosis was applied and worn full time, and an active occupational therapy program was initiated. At 12 weeks after surgery, AA and MC were weaned to nighttime use of the orthosis, and 18 weeks after the initial surgery date, they were free from the orthosis. For the other two children (NA and NP), the postoperative protocol was modified to eliminate the immediate postoperative shoulder spica cast. Final fit of the orthosis occurred immediately after the surgical procedure. They were seen 2 weeks after surgery and found to have increased range of motion, as well as active abduction, external rotation, and flexion. Occupational therapy was initiated at 4 weeks after surgery. Continued postoperative regimen included 4 to 6 weeks of full-time orthosis use, followed by 6 weeks of part-time orthosis use (Table 1).
Obstetrical brachial plexus injury is rare; however, it leads to significant functional limitations in children who do not experience spontaneous recovery. A modified L’Episcopo procedure in conjunction with a postoperative protocol that includes a custom adjustable rotation/abduction orthosis can produce an exceptional result with significant functional improvement. Previous case reports have recommended delaying surgery until the patient is 3 to 4 years old to allow compliance with treatment.9 The University of Michigan’s Department of Orthopaedic Surgery is performing modified L’Episcopo procedures on children as young as 18 months with continued success and adherence to the postoperative protocol. Four patients maintained consistent orthosis wear for the duration of treatment with no incidences of skin breakdown. No child was successful in ability to self remove the orthosis. Parents whose child experienced the initial postoperative plaster spica cast followed by the custom orthosis claimed that the orthosis was easier to care for and lighter and more maneuverable for the child. No compromises in postoperative position were made in transition from cast to custom orthosis. Although well-designed prefabricated orthoses exist, their limitation is the inability to fit them appropriately to children as young as 18 months, which necessitates custom-fabricated orthoses. The use of an appropriately fitting custom orthosis as part of the postoperative regimen for an already well-documented successful surgical procedure produces the optimum clinical success.
Use of this custom orthosis may eliminate the need for postoperative spica casting, which presents significant benefit to the child and the caregiver. Debate may exist as to the cost-effectiveness of the use of a custom orthosis as opposed to a shoulder spica cast. In assessing cost-effectiveness, the quality of life for the patient must be considered. It is also proposed that the increased intimacy of fit throughout the 6-week postoperative period increases comfort and thereby compliance. As the child loses or gains weight, or experiences atrophy of the musculature, the orthosis can be adjusted to reflect the size and shape of the patient. Maintenance of skin integrity and the ability to perform hygiene with the orthosis also increases the quality of life and comfort during this difficult postoperative period. The patient also can be weaned to nocturnal use of the custom orthosis with no compromise of position if extended wear is prescribed by the physician.
The weight of a plaster shoulder spica cast may also interfere with balance and the ability to participate in age-appropriate activities. Questions may arise as to the ability of a child of this young age to maintain compliance, given the opportunity for self removal of the orthosis, and the possibility of loss of postoperative position. Child-proofing techniques can be incorporated into the design, as necessary. These techniques include relocating chafes to open posteriorly, as well as designing trim-lines to extend dorsally over the arm to maintain containment. Buckles can also be added to replace Velcro closures.
The use of this custom-molded orthosis, including preoperative molding and the immediate preoperative procedure fit of this orthosis with the child anesthetized, is vital for successful clinical outcomes, particularly when used in place of initial 6-week shoulder spica cast.
The authors recognize the University of Michigan Orthotics & Prosthetics Center, with particular thanks to Jill Petkash, RTO, and Ammanath Peethambaran, MS, CO, for their contributions to the development of the design of this orthosis.
1.Adler J. Erb’s palsy: long term result of treatment in 88 cases. J Bone Joint Surg Am
2.Hardy AE. Birth injuries of the brachial plexus: incidence and prognosis. J Bone Joint Surg Br
3.Morrissey RT, Weinstein SL. Lovell & Winter’s Pediatric Orthopaedics
, 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2001.
4.Becker L. The cervical rib. A predisposing factor for obstetric brachial plexus lesions. J Bone Joint Surg Br
5.Gilbert A, Tassain JL. Reparation chirurgicale du Brachial dans la paralysis obstetricale. Chirurgie
6.Waters PM. Comparison of the natural history, the outcome of microsurgical repair, and the outcome of operative reconstruction in brachial plexus birth palsy. J Bone Joint Surg Am
7.Michelow BJ, Clarke HM, Curtis CG, et al. The natural history of obstetrical brachial plexus palsy. Plastic Reconstr Surg
8.Hoffer MM, Wickenden R, Roper B. Brachial plexus birth palsies: result of tendon transfers to the rotator cuff. J Bone Joint Surg Am
9.Covey DC, Riordan DC, Milstead ME, Albright JA. Modification of the L’Episcopo procedure for brachial plexus birth palsies. J Bone Joint Surg Br