[Analysis of brachial plexus injuries reported to MRM].

Field: Medicine (Health Sciences)

Upper-arm weakness (paresis) or paralysis in the newborn (Erb's palsy) usually indicates peripheral-nerve damage to the brachial plexus. Its location lateral to the lower cervical spine (C5-T1) renders it susceptible to injury by pressure or traction during pregnancy, labor or delivery. The Medical Risk Management (MRM), a "Madanes" group company, routinely receives adverse events reports from medical centers covered by its medical malpractice insurance. In the current study, the authors analyzed 536 reports of Erb's palsy in the newborn, with varying degrees of severity, which were reported to MRM during the years 1993-2004. A dedicated questionnaire with approximately 30 relevant variables was formed in order to analyze these reports. Reference values for pregnancies and deliveries in the general population were obtained from the Israeli Central Statistics Bureau, Information Department in the Ministry of Health, the Israeli Society of Maternal-Fetal Medicine, as well as relevant data in the medical literature. It was found that during the analyzed period of time, the reporting rate for Erb's palsy varied between 0.5-1.2 cases per 1,000 newborns. Compared with the general Israeli population, women in the study group were older, overweight, with higher parity and have diabetic traits. The authors noted a systematic error of underestimation of fetal weight, compared to the actual birth weight in our study group. Although, the majority of the Erb cases followed vaginal deliveries at term, 3% of the cases followed Cesarean sections, the majority of which were either elective or in early labor. A quarter of the Erb cases followed instrument delivery, while the rate of instrumental deliveries in the general population averaged only 5% throughout the study period. In half of the Erb cases, difficulty in extraction of the shoulder (shoulder dystocia) of the involved arm was found in the delivery medical record, but reference to shoulder or head extraction was noted in only half of the cases following vaginal deliveries. However, the rate of medical records with adequate reference to shoulder or head extraction increased from 44% in the beginning, to 74% at the end of the analyzed study period. The average birth weight of our study group was 3888+569 grams, which is significantly higher than the average birth weight in the general population. It was also noted that birth weights of Erb cases are of higher percentiles on the Israeli nomogram of gestational age adjusted birth weights. Thus, 53% of the newborns in our study group were above the 90th percentile and 31% above the 97th percentile of the general population nomogram. Various risk factors for brachial plexus injury were found in this large sample of Erb's palsy cases in Israel. However, the relative importance of each of these factors cannot be determined due to lack of an appropriate control group and valid reference data for the general population of pregnancies and deliveries during the analyzed study period. Nonetheless, the dedicated questionnaire, which was developed for this analysis, may assist in compiling real-time data to support the findings of this study.