The value of detailed strength testing monthly, up to 6 months of age, in predicting complete recovery was determined in a prospective study of 80 infants with brachial plexus injury followed at the Brachial Plexus Palsy Center, St Louis Children’s Hospital, MO. Strength was determined using the British Medical Research Council Scales: 0 = no contraction, 1 = trace contraction, 2 = active movement with gravity eliminated, 3 = active movement against gravity, 4 = active movement against gravity and resistance, 5 = normal. Range of motion and developmental skills were also assessed monthly up to 6 months, and then every 3 to 6 months, until complete recovery or absence of further improvement to age 2 years. Therapy was conducted at home and at the center.
The serial clinical examinations clearly differentiated patient outcomes: 53 (66%) showed complete recovery, 9 (11%) had mild weakness (4/5 strength), 7 (9%) moderate weakness (3/5 strength), and 11 (14%) severe weakness (0-2/5 strength). The permanently disabled infants were followed for a mean of 4.4 years. All of the infants with complete recovery had developed antigravity strength in biceps, triceps, and deltoid muscles by 4.5 months of age, and the majority by 3 months. Distal weakness resolved more rapidly, by 4 to 8 weeks. Of the 11 with severe residual disability, none had better than 2/5 strength in proximal muscles at age 6 months, and 64% had 0-1/5 strength in wrist and fingers. 
COMMENT. In infants with neonatal brachial plexus palsy, a detailed clinical examination with strength testing up to 6 months of age may distinguish the two-thirds who will make complete recovery from the 14% of infants left with a permanent severe disability. The early identification of those with a poor outcome may help in selection of patients for surgery at or after 6 months. In some studies, recovery has continued up to 9 months, and surgical intervention at an earlier age would be advised only rarely, with total plexus lesions.
The outcome in this study is at variance with that of 149 patients followed and treated conservatively at the Children’s National Medical Center, Washington, DC. (Eng GD et al. 1996; see Progress in Pediatric Neurology III, 1997;357-9). Only 6 (4%) showed complete recovery, and 92 (62%) had mild impairments of strength and function. The initial clinical impairment ratings at <3 months of age correlated closely with later exams and with serial electrodiagnostic studies. Selection criteria for surgery were not clearly defined.
Strombeck C et al, at Stockholm, recommend that surgery for OBP should be delayed until after 6 to 9 months. They examined the functional outcome at age 5 years of 247 children with OBP, with or without microsurgical reconstruction. The only benefit of operation was an improved shoulder range of movement, when compared to non-operated patients. Outcome was not correlated with timing of operation, before or after 6 months. (see Ped Neur Briefs April 2000;14:25-26).