Management of Brachial Plexus Birth Injuries at British Columbia Children's Hospital

Abstract

A multidisciplinary team at BC Children's Hospital provides brachial plexus birth injury management for our provincial catchment area. Although compared with many centers we service a relatively small clinic population, we have the benefit of universal health care, province-wide reach, and accessible research infrastructure. In 2008, we created the Sup-ER protocol, which includes an orthosis that passively positions the neonatal shoulder into more idealized glenohumeral contact during early growth. We have since shown that our Sup-ER patients have better shoulder outcomes, require less brachial plexus surgery, and need fewer shoulder tendon transfers than those patients treated in our clinic prior to 2008. We have also found that the rate and degree of elbow flexion contractures are reduced compared with results reported in the literature.

In British Columbia, the incidence of brachial plexus birth injuries (BPBIs) is 1.24/1,000 live births occurring in a provincial population of a little over 5 million. ¹ Pre-, peri-, and postnatal care is covered by public universal health insurance, and except for time and travel expenses, cost of care for the BPBI patient is not borne by the family. Almost all BPBIs of significance in the province are referred to our center, where a multidisciplinary brachial plexus clinic has been active since 1996. This clinic and its care pathways were initially modeled after the Hospital for Sick Children (HSC) methodology. ² Our clinic population averages ∼15 unique new patient referrals each year.

Although the first decade of our clinic followed the HSC conceptual pathways, ² our approaches, focus, and concepts of care eventually evolved to also consider the shoulder musculoskeletal unit more comprehensively. Early internal rotation–related joint changes appeared to be as or more important as a cause of poor active movement in the shoulder and the elbow than the actual nerve injuries themselves. Brachial plexus nerve–based surgery would not help the shoulder joint move better, and shoulder internal rotation could affect elbow flexion. Our clinic pathways gradually evolved to focus on early internal rotation contracture prevention, and we have seen reduced overall surgical requirements, more ability to implement simpler distal nerve transfers, and overall improved functional outcomes. ^{3 4 5} We hope and expect that further evolution of care will continue as ongoing evidence indicates.

Our regular team members include those certified in physiotherapy, occupational therapy, plastic surgery, and orthopaedics, and we have close connections and referral pathways to radiologists experienced in brachial plexus shoulder ultrasound and magnetic resonance imaging (MRI), anesthesiologists, neurologists, and the chronic pain team. Patients are evaluated in the brachial plexus clinic by plastic surgeon(s) and therapists and will see our orthopaedic surgeon separately if required. Close mentorship and communication with community-based therapists are maintained, and under their guidance, family caregivers provide the primary therapy. In-person evaluations are preferred, but in pandemic isolation conditions, or when travel is difficult or dangerous in our province, virtual sessions may be arranged through confidential online meeting platforms, sometimes with the community therapist present with the family. Multidisciplinary clinics occur ∼3 days per month, varying with volume, and longer occupational therapy-only appointments are booked to coincide whenever possible.

In ideal conditions, newborn referrals are triaged to have the first consultation occur at ∼3 weeks of age and later referrals are triaged to as soon as they can be seen. As most families are first seeking information, along with the appointment time, a short educational “packet” is provided by email to the family, describing the basics of the condition and diagrams of simple range-of-motion exercises to be started even before the first appointment. We also maintain a website that provides information for parents and health care professionals, as well as describes research studies. ⁶ In ideal conditions, patients are seen approximately once per month following initial consult, and when their recovery has stabilized, at least once per year until they graduate from our pediatric hospital.

Prenatal and birth history, initial presentation, comorbidities, and clinical and developmental progress are documented, and patients are evaluated using the HSC Active Movement Scale (AMS). ⁷ Our clinic has modified the measurement and AMS documentation of external/internal rotation and supination/pronation to additionally include the degrees from neutral zero. ⁴ We have recently started to proactively record passive elbow range. ⁵ We maintain a longitudinal database that captures these data prospectively.

Neurapractic Injuries

If a patient has near or full recovery of all movements (6 or 7/7 on the AMS) at initial 3-week consult, families are reassured of the likelihood of a good long-term prognosis. A full explanation of the injury with images is presented. A hands-on demonstration and teaching of range-of-motion exercises and monitoring of early tightness is also undertaken. These patients are seen 1 month later, and if all movements are still full with no tightness, they are seen again at ∼5 to 6 months of age at which point they are usually discharged, in the absence of any new clinical concerns. Contact information for the clinic is provided should there be further follow-up questions.

Patients with More Severe Injuries

Patients with a flail limb, hand or wrist weakness, or significantly reduced shoulder and elbow function are also treated initially with the same caregiver range-of-motion exercises and referral to a community therapist. They are followed up in our clinic at ∼6 weeks of age. If at that time shoulder external rotation scores are 2 or less on the AMS scale, or there is joint tightness, they will be fitted with a long arm extension orthosis and start a passive supination and shoulder external rotation positioning protocol (Sup-ER) ( Fig. 1 ). ^{4 8} A shoulder ultrasound determining α angle is ordered as contemporaneously as possible, including imaging in and out of splint. An α angle of ∼30 degrees is our accepted goal of “normal.” ^{9 10}

Fig. 1.

The Sup-ER orthosis with a custom volar thermoplastic elbow extension splint and a separate neoprene waist belt. The arm splint is secured with Fabrifoam SuperWrap and Velcro straps. (Reproduced with permission from Verchere et al. ³ )

Sup-ER Protocol

Since 2008, ∼15% of clinic patients present with BBPI severe enough to have been treated with our protocol of passive positioning into shoulder external rotation and forearm full (or neutral) supination. ⁴ If started at 6 to 8 weeks of age, we encourage 20 to 22 hours per day of orthosis wear, with full range-of-motion stretches at intervals throughout the day with breaks from orthosis. ⁸ This takes advantage of the long newborn sleep periods and allows maximized glenohumeral contact time during a period of rapid growth, a concept similar to the Pavlik harness for hips. ³ Follow-up by phone or video with the occupational therapist at ∼2 weeks is recommended to make sure that orthosis wear and range of motion are appropriate, and full clinic follow-up with ultrasound is planned monthly after the orthosis is initiated.

With the institution of the Sup-ER protocol, we have seen sustained improvement in external rotation and supination AMS scores at 2 years, a reduction in brachial plexus exploration and grafting surgical indications, a reduction in internal rotation contractures (both in surgical indications and better outcomes of active motion; Figs. 2 and 3 ), and a decrease in elbow flexion contractures ( Fig. 4 ). ^{3 4 5 11}

Fig. 2.

Mean AMS scores by age and by historical (before Sup-ER protocol) and recent (Sup-ER protocol) groups for external rotation, supination, and elbow flexion. Dotted lines represent 95% confidence intervals. (Reproduced with permission from Wong et al. ¹¹ )

Fig. 3.

Pre- and postoperative active external rotation in patients with tendon transfer surgeries by historical (before Sup-ER protocol) and recent (Sup-ER protocol) groups. (Reproduced with permission from Wong et al. ¹¹ )

Fig. 4.

Elbow extension passive range of motion of children with brachial plexus injuries reported in comparable case series. ^{13 14} (Reproduced with permission from Yefet et al. ⁵ )

Babies that show monthly improvement in their active range, no sign of tightness, improvement or stability of their α angle, and progression of developmental skills will have their orthosis time gradually decreased to nights and naps until they no longer tolerate the orthosis. ³ Range-of-motion exercises remain an important part of care. The position of the forearm is monitored, and oversupination can be avoided by modifying the forearm part of the splint toward neutral where indicated. ⁸ Early prototypes of the Sup-ER splint positioned the elbow in flexion, but tendency toward elbow flexion contractures caused us to change to extended elbow splints ^{3 8} ; ultrasound confirms that effectiveness of glenohumeral position is maintained. Generally, the recommended duration of orthosis use ranges from 8 to 12 months. ³ Once patients have three consecutive acceptable α angle measurements, we discontinue the screening ultrasounds. We have anecdotally observed that many patients will correct their α angles within 1 or 2 monthly Sup-ER protocol visits.

At 3 months of age, patients with evidence of significant hand and wrist weakness, absence of elbow flexion, flail limb, or other signs of multiroot avulsion will be recommended for surgical exploration and grafting of the brachial plexus with or without accessory nerve transfer. ⁴ (Please see technical detail section that follows). Upper plexus–injured patients making progress in shoulder and elbow recovery will continue to be followed monthly in the clinic.

As early as 4 to 5 months of age, if a patient has tightness of internal rotation, or is developing an elbow forward habit, an active-use humeral-constraint band may be recommended to limit shoulder forward flexion and encourage active external rotation during play ( Fig. 5 ). ⁴ Prior to our clinic's use of this band, we recommended Botox injection into the pectoralis major and subscapularis muscles guided by electric stimulation in the operating room, followed by a 3-week external rotation cast. ⁴ More recently, the latter treatment is indicated only if the constraint band is noneffective, or the shoulder is significantly tight, subluxed, or dislocated. Rarely, a patient may have enough unresponsive tightness that surgical shoulder release is required as early as 6 months of age. ⁴

Fig. 5.

Elbow forward constraint band on a patient who had external rotation AMS score of 4/7 and an elbow forward habit 1 month prior. At this assessment, a 7/7 external rotation AMS score was maintained. (Reproduced with permission from Wong et al. ¹¹ )

Patients with incomplete nerve recovery are followed monthly with the orthosis and its wear time modified as needed, based on clinical assessment and developmental progression. At ∼9 months of age, we attempt “the cookie test” described by Clarke and Curtis. ¹² If a patient has weakness of elbow flexion in the presence of good shoulder recovery and joint anatomy, we will recommend an Oberlin nerve transfer between 10 and 12 months of age, and occasionally, where shoulder weakness indicates, triceps to axillary nerve transfer may be added. ¹¹ Since the institution of the Sup-ER protocol, our clinic patients have not met the indications for exploration and grafting of the plexus later than the 3 to 4 months of age time period. ¹¹

Brachial Plexus Exploration Technique

Patients have a preoperative MRI under general anesthesia to determine levels of root avulsion for surgical planning. We do not have access to preoperative or intraoperative electrodiagnostic studies for brachial plexus surgery, with the exception of intraoperative hand-held nerve stimulators.

Patients are positioned supine on gel, with a small gel bolster between the scapulae, and the head supported on a small gel donut, slightly extended and turned away from the operative site. The shoulder, neck, upper chest, and lower face are prepped with aqueous chlorhexidine or povidone, and both legs are prepped and free-draped to the top of the thighs. Preoperative cefazolin is usually prescribed.

A low unilateral transverse neck crease incision is used for access, and sural nerves are harvested after exposure and resection of the indicated neuroma. Neuromata-in-continuity are initially excised at the point where the nerve transitions to visibly normal. Phrenic nerves are protected throughout dissection. Clavicles are usually easily mobilized inferiorly and anteriorly for access and have not required osteotomy. Inked specimens of resected neuroma ends are examined by the pathologist to indicate absence of scar and presence of healthy axons at all resection sites. Re-resection is undertaken until satisfactory pathology findings are reported. Neurolysis of roots and divisions that have visible longitudinal continuity and good nerve stimulation is undertaken where indicated. The resection nerve gaps are measured in centimeters with the patient resting in the maximally stretched position. These gap lengths are used to determine the most efficient patterns of grafting. When transferred, the accessory nerve is found on the anterior surface of the trapezius with the nerve stimulator and dissected inferiorly as far as possible. Then, branches are divided from the lower muscle in a retrograde direction, dividing only enough to allow for the nerve to be mobilized into a position to coapt with the suprascapular nerve.

Harvesting of each of the sural nerves is undertaken in a flexed hip supine position, with sterile tourniquets, without endoscopy, using a posterior malleolar incision, midcalf transverse incision, and a transverse popliteal crease incision. In 3-month-old patients, our transverse incisions are 1.5 to 2 cm long, and we can usually harvest 10 to 11 cm lengths of sural grafts.

Grafts are placed retrograde one by one into the nerve defects to satisfy as many exposed nerve root and distal fascicles as possible and are cross-grafted and allowed space between them for revascularization. Coaptation is completed under the microscope, placing grafts directly on exposed fascicles and fixating with fibrin glue alone.

After assuring on multiple occasions that external rotation of the shoulder does not affect the tension of the grafted plexus, patients are now taped postoperatively into the Sup-ER position (shoulder external rotation, elbow extension, forearm supination) with elastic-fabric tape on protective transparent dressing film for 3 weeks ( Fig. 6 ). Caregivers are advised to avoid movements or positions that pull the shoulder far away from the ear, but the neck is not immobilized and babies can move their head within their supported normal range. After the postoperative tape is removed, they return to the Sup-ER protocol.

Fig. 6.

Upper limb positioning with elastic-fabric tape on protective transparent dressing film postbrachial plexus exploration. (Reproduced with permission from Wong et al. ¹¹ )

Shoulder Contracture Surgery

As early as 1 to 2 years of age, if there has been little recovery of active shoulder external rotation, significant subluxation, or (especially in late referred patients) glenohumeral dislocation, our orthopaedic colleagues become actively involved. Ultrasound-confirmed closed reduction with Botox and external rotation cast for 3 weeks is attempted, with subscapularis slide and casting as a second-tier option, and release of subscapularis and latissimus dorsi tendon transfer to the posterior capsule as a third-tier option for more severe cases. Subscapularis slide surgery can be undertaken as early as 4 months of age, and tendon transfers usually after 2 years of age. Glenoid osteotomy with tendon transfer has been undertaken for patients with severe glenohumeral dysplasia, but rarely in the Sup-ER protocol era. The last glenoid osteotomy was done 11 years ago, and humeral de-rotational osteotomy has not been undertaken in our clinic patients since 2001. ¹¹

Conclusion

In conclusion, although our clinic population is very small, we have a structured management pathway universally accessible to our patients with BPBIs that involves a multidisciplinary team, proactive database documentation, and provision of consistent innovative evidence-based care. The introduction of the Sup-ER protocol early in the neonatal period has provided long-term benefit to our patients' outcomes.