Black or white?

LETTERS TO THE EDITORS Brachial plexus impairment-A birth trauma? To the Editors: The article by Jennett et al. Qennett RJ, Tarby TJ, Kreinick CJ. Brachial plexus palsy: An old problem revisited. AM J OBSTET GYNECOL 1992; 166: 1673-7) is important because it suggests a role for intrauterine maladaptation in brachial plexus impairment. We agree that factors other than birth trauma, mostly in combination with asphyxia, have to be considered. One might assume that intrauterine maladaptation, and, consequently, pressure neuropathy have a better prognosis; this is confirmed by the fact that all the children in the series had a favorable outcome and that there were no lesions of Klumke's type. This experience, however, differs from that in the literature surveys, which estimate the incidence of brachial plexus impairment to be between 0.5 and 3 per 1000 live births in the hospital, with persistent disability in between 4% and 20%. '·4 It is a fact that the incidence and severity of obstetric plexus brachial is palsy have decreased in recent years, in all probability because of improved obstetric care and rehabilitation by intensive physiotherapy. It is difficult to reconcile these differences except to point out the difficulty in judging results without uniform tests. In our own series of 223 obstetric cases in which the patients were referred to this hospital for evaluation, 86 children were operated on according to the criteria of Gilbert et al. 5 and Hentz and Meyer. 6 Neuromas, ruptures, or signs of avulsion were found in all these patients. The obstetric history of each patient mentioned risk factors such as shoulder dystocia with extreme lateral traction of the fetal head or a difficult breech delivery, in most cases combined with asphyxia. A. CJ. Slooff, MD, PhD Department of Neurosurgery, De Wever Hospital, P.O. Box 4446, 6401 ex Heerlen, The Netherlands

J.M.H. Ubachs, MD, PhD Department of Obstetrics and Gynaecology, De Wever Hospital, P.O. Box 4446, 6401 ex Heerlen, The Netherlands

careful clinical evaluation has added an important dimension to the management of neonatal brachial plexus impairment. We do not see a conflict, regarding incidence or outcome, between our results and those from the literature. The incidence of brachial plexus impairment in our series was 0.7 cases per 1000 live births. This compares well with the range quoted by Sloof and Ubachs. We did not ascertain long-term outcome or disability in our series but suspect, as do Sloof and Ubachs, that there may be a difference in prognosis between the frank shoulder dystocia group and that group with no identified shoulder dystocia. This expected difference may be obscured by a real, if not apparent, difference in the conditions necessary for shoulder dystocia in the primiparous delivery. However, antenatally derived brachial plexus impairment is not universally transitory. One of us (T..J.T.) has recently seen a 7 -year-old patient with residual brachial plexus impairment from an insult that occurred antenatally. This patient had been noted to have atrophy in the affected arm within 24 hours of delivery. Raymond J. Jennett, MD, Theodore J. Tarby, MD, and Carol J. Kreinick, MA 2601 E. Beekman Place Phoenix, AZ 85016-7450

Black or white? To the Editors: I have read with interest the article by Johnson et al. Qohnson MJ, Paine LL, Mulder HH, Cezar C, Gegor C, Johnson TRB. Population differences of fetal biophysical and behavioral characteristics. AM J OBSTET GYNECOL 1992;166:138-42). This otherwise excellent article suffers from the same problem that has occurred in many others recently published: To wit, how does one define "black" and "white"? A statement by the authors as to their criteria for this distinction would be most welcome. Bruce A. Harris, Jr., MD The University of Alabama, PJOO Volker Hall, 1600 University Blvd., UAB Station, Birmingham, AL 35294-0019

REFERENCES 1. Hardy AE. Birth injuries of the brachial plexus: incidence and prognosis. J Bone Joint Surg 1981 ;63b:98-10 1. 2. Greenwald AG, Schutte PC, Shiveley JL. Brachial plexus birth palsy. J Pediatr Orthop 1984;4:689-92. 3. Painter M. Brachial plexus injuries in neonates. Int Pediatr 1988;3:120-4. 4. Jahnke AH Jr, Bovill DF, McCarroll HR Jr, James P, Ashley RK. Persistent brachial plexus birth palsies. J Pediatr Orthop 1991;11:533-7. 5. Gilbert A, Brockman R, Carlioz H. Surgical treatment of brachial plexus birth palsy. Clin Orthop 1991;264:39-47. 6. Hentz VR, Meyer RD. Brachial plexus microsurgery in children. Microsurgery 1991; 12: 175-85.

Reply To the Editors: We thank Slooff and Ubachs for their comments regarding the incidence of surgical lesions in infants failing to recover promptly from neonatal brachial plexus impairment. Surgical intervention after

230

Reply To the Editors: We appreciate the interest of Harris in our recent article. The race of the study patients was determined first by examination of the medical record. This was then verified by the mother before enrollment in the study. No attempt was made to record the race of the father, although we acknowledge that in future studies this would be an important variable. Mary Jo Johnson, MD Division of Maternal-Fetal Medicine, Houck 228, 600 N. Wolfe St., Baltimore, MD 21205

The obstetric bonnet is not a new instrument To the Editors: Elliott et al. in their article regarding the "obstetric bonnet" (Elliott BD, Ridgway, LE, Berkus MD, Newton ER, Peairs W. The development and