Association pour la réparation des atteintes du plexus brachial et pour la prévention des risques associés lors des naissances
Obstetrical brachial plexus paralysis (OBPP) refers to partial or complete paralysis of the arm and hand due to injuries to the upper nerve roots during birth. Paralysis is usually noted at the time of child delivery, affecting one newborn out of 2000. In general, there is substantial spontaneous recovery in the majority of cases. The degree of recovery depends primarily on the severity of the lesion (permanent, temporary, partial or complete paralysis).
What is the brachial plexus?
Brachial plexus (figure 1) is a network of nerves that is located roughly at the base of the neck, and innervates upper limbs. Each brachial plexus is formed by the union of the last four cervical nerves (originating in the cervical region of the spinal cord, called C5 to C8 levels) and the first dorsal nerve root (D1). Some forms of paralysis affect all the roots and others only a few.
Figure 1: Location of brachial plexus
Plexus brachial: Brachial plexus
Moelle épinière: Spinal Cord
What are the clinical signs of OBPP?
One of the newborn's arm is paralyzed (paralysis is generally unilateral). It is often the result of a complicated delivery, due to a combination of high birth weight, assisted delivery with forceps, difficulty delivering the shoulders, obstetrical maneuvers, etc. Once the diagnosis is validated, an assessment of lesions allows the identification of which nerve roots were damaged, but not their precise cause.
Complementary examinations may be considered: radiographic examination is generally used to detect associated injuries (clavicle fracture); EMG evaluates the electrical activity of the nerves and identifies the site of lesions (at the end of the first month of life); myelography— a type of radiographic examination of the spinal cord—is used to look for typical signs of nerve injury. In severe forms, these examinations allow the localization and assessment of the nature of damage.
Descriptive clinical presentation
Signs and symptoms may vary significantly:
- In paralysis located in the upper levels (75% of cases), the shoulder is inactive, the arm hangs down passively along the side of the body, the wrist may be affected, but the hand function is preserved. Then, paralysis extends to C5 and C6 (figure 2) and sometimes C7 level (Erb-Duchenne paralysis results from injury to the C5 and C6 levels).
- In paralysis located in lower levels (affecting C8 to D1 levels), the arm paralysis is associated with partial or complete paralysis of the hand.
- Complete and permanent paralysis (C5 to D1 levels) is rare
- Other disorders are possible: sensory and vasomotor (limb pallor) disorders, associated fracture (clavicle, humerus), and impaired diaphragm (when C4 level is affected, resulting in respiratory distress), Claude Bernard-Horner syndrome (eye impairment).
Figure 2: The brachial plexus
Racines : Nerve roots
Paralysies hautes : Paralysis to upper levels
Paralysies basses : Paralysis to lower levels
Paralysies totales : Complete paralysis
Clavicule : Clavicle
What are the causes?
Nerves are damaged when excessive traction is placed on the baby's head at birth, whether it is in vertex or breech presentation (buttocks first) during delivery of the head or arms. Excessive tractions may cause nerves to become stretched. In fact, nerve roots can be stretched, ruptured, or avulsed.
How does the disease progress?
In the first days of life, making an accurate prognosis is extremely difficult. Spontaneous recovery—by nerve regeneration—depends on the severity of lesions. Many babies fully recover from OBPP resulting from excessive stretching in the first weeks following birth. Full recovery is usually observed in babies aged less than 3 months. In the other cases likely to cause permanent paralysis, a precise diagnosis can be reached only after several months. At that point, surgical interventions to repair or compensate nerve function may be considered. After six months of age, muscles that did not fully recover do not get back to normal.
The final disability depends on the level of recovery. In the most critical cases, the arm and hand functions are compromised. In the majority of cases, however, only the hand remains functional and, the mobility and strength of the arm may be reduced. Paralysis, if persistent, does not get aggravated, but sequelae due to complications may appear: muscle shortening, contraction, osteo articular deformities, and limb disuse. We must prevent muscle shorthening, muscular imbalance in the shoulder must, and maintain the range of motion. OBPP does not seem painful to newborns. However, some constraints (pain, tingling sensation) are reported in adults who sustained brachial plexus paralysis (accidentally caused).
What are the suggested treatments and management strategies?
Prevention involves the prenatal detection of any lack of proportion between the size of the foetus and the mother's pelvis through ultrasound examination or other methods. When a lack of proportion can be validated by radiographic measurement of the pelvis size, a caesarean section is performed. In extreme cases, vaginal delivery may be attempted with caesarean section if necessary. Predictable birth weight of more than 4 kg (8 lbs), prior complicated deliveries, and family history of OBPP (on the mother's side) require careful monitoring.
The child must be monitored in the very first weeks. Helpful treatments to be used may include: physical therapy (daily exercise sessions during the period of spontaneous recovery, basically the first year of life), and following the eventual surgical interventions; temporary postural control (bandages, splints); electro-stimulation of muscles; nerve grafts (from three months of age, and ideally during the first year of life; grafts come from the child); muscle transfers; palliative surgical interventions (elimination of discomforting postures or awkward movements due to muscle shortening for instance).
There is a scarcity of research in brachial plexus paralysis. In terms of prevention, the 1991 edition of French journal "Mises à jour en Gynécologie Obstétrique" (cf. below) bring clarifications about the procedures undertaken when the risk has been identified. In terms of recovery, on the other hand, nerve microsurgery has only been available since the beginning of the 1980's.
Role of family and friends
When children are young, it is important to place their affected arm onto their trunk while carrying them. When lying in bed, one of their pyjama's sleeves can be tied to their stomach to allow them to play with their hands. If their arm is not fully paralyzed, elastic bandages can be used to bring their arms in a position allowing active muscles to work. Toys manipulated with both hands are an excellent source of stimulation to exert their affected arm.
For more information
A-BRAS : Association pour la réparation des atteintes du plexus brachial et pour la prévention des risques associés lors des naissances, 41 rue Saint Liesne, 77000 Melun.
Publications (for physicians and paramedics, in French only)
Burger-Wagner A. et coll., Rééducation en orthopédie pédiatrique. Paris, Masson, 1991.
Gilbert A., Dumonfier C., Paralysie ostetricale : évolution et traitement chirurgicale. La Revue du praticien, n° 30, 21 déc. 1989, 2707-2712.
Schall J.-P. et coll., La disproportion fœto-pelvienne. Mise à Jour en Gynécologie et Obstétrique, Collège National des Gynécologues et Obstétriciens Français, 215-245, Paris, Vigot, 1991.