Are there modifiable risk factors that may predict the occurrence of brachial plexus injury?

Epidemiology of Brachial Plexus Birth Injury and the Impact of Cesarean Section on Its Incidence

BACKGROUND

While prior research provided thorough analysis of the epidemiology of brachial plexus birth injury (BPBI) from 1997 to 2012, recent trends are unknown. The goal of this study was to update the understanding of the epidemiology and risk factors for BPBI.

METHODS

Installments of the Kids' Inpatient Database (1997 to 2019) were used to estimate BPBI incidence in the United States in comparison to several independent variables over time. An interaction between cesarean (C-) section and newborn weight was explored by defining BPBI rates in a stratified manner. A logistic regression model accounting for this interaction was developed to produce odds ratios for independent factors. Lastly, the temporal relationship between BPBI rates and C-section rates was explored using linear regression.

RESULTS

BPBI rates were steady around 0.9 to 1.1 per 1000 live births between 2006 and 2019. C-section rates were similarly stable between 32.3% and 34.0% over this period. Stratified analysis indicated C-section delivery was protective against BPBI across newborn weight classes, but the magnitude of this protective value was highest among newborns with macrosomia. Shoulder dystocia was the strongest risk factor for BPBI in the logistic regression model [adjusted odds ratio (AOR): 56.9, P<0.001]. The AOR for a newborn with macrosomia born through C-section (AOR: 0.581, 95% CI: 0.365-0.925) was lower than that for a normal weight newborn born vaginally (AOR: 1.000, P=0.022). Medicaid insurance coverage (AOR: 1.176, 95% CI: 1.124-1.230, P<0.001), female sex (AOR: 1.238, 95% CI: 1.193-1.283, P<0.001), and non-White race (AOR: 1.295, 95% CI: 1.237-1.357, P<0.001) were independent risk factors for BPBI. Over time, the rate of BPBI correlated very strongly with the rate of C-section (R2=0.980).

CONCLUSIONS

While BPBI and C-section rates were relatively stable after 2006, BPBI incidence strongly correlated with C-section rates. This highlights the need for close surveillance of BPBI rates as efforts to lower the frequency of C-section evolve. Female, Black, and Hispanic newborns and children with Medicaid insurance experience BPBI at a higher rate, a finding which could direct future research and influence policy.

LEVEL OF EVIDENCE

Level IV-case series.

Maternal Epidemiology of Brachial Plexus Birth Injuries in California: 1996 to 2012

OBJECTIVE

This study aimed to evaluate the incidence of brachial plexus birth injury (BPBI) and its associations with maternal demographic factors. Additionally, we sought to determine whether longitudinal changes in BPBI incidence differed by maternal demographics.

STUDY DESIGN

We conducted a retrospective cohort study of over 8 million maternal-infant pairs using California's Office of Statewide Health Planning and Development Linked Birth Files from 1991 to 2012. Descriptive statistics were used to determine BPBI incidence and the prevalence of maternal demographic factors (race, ethnicity, age). Multivariable logistic regression was used to determine associations of year, maternal race, ethnicity, and age with BPBI. Excess population-level risk associated with these characteristics was determined by calculating population attributable fractions.

RESULTS

The incidence of BPBI between 1991 and 2012 was 1.28 per 1,000 live births, with peak incidence of 1.84 per 1,000 in 1998 and low of 0.9 per 1,000 in 2008. Incidence varied by demographic group, with infants of Black (1.78 per 1,000) and Hispanic (1.34 per 1,000) mothers having higher incidences compared with White (1.25 per 1,000), Asian (0.8 per 1,000), Native American (1.29 per 1,000), other race (1.35 per 1,000), and non-Hispanic (1.15 per 1,000) mothers. After controlling for delivery method, macrosomia, shoulder dystocia, and year, infants of Black (adjusted odds ratio [AOR] = 1.88, 95% confidence interval [CI] = 1.70, 2.08), Hispanic (AOR = 1.25, 95% CI = 1.18, 1.32), and advanced-age mothers (AOR = 1.16, 95% CI = 1.09, 1.25) were at increased risk. Disparities in risk experienced by Black, Hispanic, and advanced-age mothers contributed to a 5, 10, and 2% excess risk at the population level, respectively. Longitudinal trends in incidence did not vary among demographic groups. Population-level changes in maternal demographics did not explain changes in incidence over time.

CONCLUSION

Although BPBI incidence has decreased in California, demographic disparities exist. Infants of Black, Hispanic, and advanced-age mothers are at increased BPBI risk compared with White, non-Hispanic, and younger mothers.

KEY POINTS

· The incidence of BPBI has decreased over time.. · Demographic disparities in BPBI incidence and risk exist.. · Infants of Black, Hispanic, and advanced age mothers are at greatest risk of BPBI..

Radiographic imaging modalities for perinatal brachial plexus palsy: a systematic review

PURPOSE

Perinatal brachial plexus palsy (PBPP) has a wide spectrum of clinical symptoms that can range from incomplete paresis of the affected extremity to flaccid arm paralysis. Although there is a high rate of spontaneous recovery within the first two years of life, it remains challenging to determine which patients will benefit most from surgical intervention. The diagnostic and predictive use of various imaging modalities has been described in the literature, but there is little consensus on approach or algorithm. The anatomic, pathophysiological, and neurodevelopmental characteristics of the neonatal and infant patient population affected by PBPP necessitate thoughtful consideration prior to selecting an imaging modality.

METHODS

A systematic review was conducted using six databases. Two reviewers independently screened articles published through October 2021.

RESULTS

Literature search produced 10,329 publications, and 22 articles were included in the final analysis. These studies included 479 patients. Mean age at time of imaging ranged from 2.1 to 12.8 months and investigated imaging modalities included MRI (18 studies), ultrasound (4 studies), CT myelography (4 studies), and X-ray myelography (1 study). Imaging outcomes were compared against surgical findings (16 studies) or clinical examination (6 studies), and 87.5% of patients underwent surgery.

CONCLUSION

This systematic review addresses the relative strengths and challenges of common radiologic imaging options. MRI is the most sensitive and specific for identifying preganglionic nerve injuries such as pseudomeningoceles and rootlet avulsion, the latter of which has the poorest prognosis in this patient population and often dictates the need for surgical intervention.

Maternal body-mass-index and neonatal brachial plexus palsy in a California cohort

OBJECTIVE

To evaluate risk factors and describe the association between maternal pre-pregnancy body-mass-index (BMI) and neonatal brachial plexus palsy (BPP) in vaginal deliveries with and without shoulder dystocia.

METHODS

This is a retrospective cohort study of singleton, non-anomalous, term vaginal deliveries in California (2007-2011). Deliveries were classified as with or without shoulder dystocia. Our primary outcome was BPP and the independent variable of interest was maternal pre-pregnancy BMI, which was categorized as underweight (<18.5 kg/m²), normal weight (18.5-24.9 kg/m²), overweight (25-29.9 kg/m²), obesity I (30-34.9 kg/m²), obesity II (35-39.9 kg/m²) and obesity III (≥40 kg/m²). We evaluated demographics, maternal, labor, and neonatal characteristics using chi-squared tests and assessed the association of pre-pregnancy BMI with BPP using multivariable logistic regression models.

RESULTS

In our cohort of 1,395,761 women, there were 21,463 deliveries with shoulder dystocia and 1,374,298 deliveries without shoulder dystocia. Among deliveries with shoulder dystocia, BPP was observed more frequently in neonates born to women with BMI categorized as overweight (32% vs. 29%; p < .001), obesity I (22% vs. 14%; p < .001), obesity II (10% vs. 6%; p < .001), and obesity III (8% vs. 3%; p < .001). After adjusting for confounders, the odds of BPP in deliveries with shoulder dystocia was significantly higher for women who were overweight (aOR = 1.65; 95% CI: 1.35-2.01), obesity I (aOR = 2.33; 95% CI: 1.86-2.90), obesity II (aOR = 2.56; 95% CI: 1.92-3.40), and obesity III (aOR = 3.80; 95% CI: 2.75-5.25). In deliveries without shoulder dystocia, BPP was more common in women with a BMI that was overweight (29% vs. 25%; p < .001), obesity I (17% vs. 11%; p < .001), obesity II (9% vs. 4%; p < .001), and obesity III (8% vs. 2%; p < .001). In this cohort, multivariable regression model showed similar results in women with a BMI that was overweight (aOR = 1.47; 95% CI: 1.19-1.81), obesity I (aOR = 1.99; 95% CI: 1.55-2.54), obesity II (aOR = 2.79; 95% CI: 2.04-3.83), and obesity III (aOR = 5.05; 95% CI: 3.63-7.03).

CONCLUSION

Rising maternal pre-pregnancy BMI is associated with an increased risk of BPP in vaginal deliveries with and without shoulder dystocia. Preconception interventions targeting weight management may be beneficial in reducing BPP in all deliveries.

Risk factors for neonatal brachial plexus palsy: a systematic review and meta-analysis

AIM

To provide a comprehensive update on the most prevalent, significant risk factors for neonatal brachial plexus palsy (NBPP).

METHOD

Cochrane CENTRAL, MEDLINE, Web of Science, Embase, and ClinicalTrials.gov were searched for relevant publications up to March 2019. Studies assessing risk factors of NBPP in relation to typically developing comparison individuals were included. Meta-analysis was performed for the five most significant risk factors, on the basis of the PRISMA statement and MOOSE guidelines. Pooled odds ratios (ORs), 95% confidence intervals (CIs), and across-study heterogeneity (I² ) were reported. Reporting bias and quality of evidence was rated. In addition, we assessed the incidence of NBPP.

RESULTS

Twenty-two observational studies with a total sample size of 29 419 037 live births were selected. Significant risk factors included shoulder dystocia (OR 115.27; 95% CI 81.35-163.35; I² =92%), macrosomia (OR 9.75; 95% CI 8.29-11.46; I² =70%), (gestational) diabetes (OR 5.33; 95% CI 3.77-7.55; I² =59%), instrumental delivery (OR 3.8; 95% CI 2.77-5.23; I² =77%), and breech delivery (OR 2.49; 95% CI 1.67-3.7; I² =70%). Caesarean section appeared as a protective factor (OR 0.13; 95% CI 0.11-0.16; I² =41%). The pooled overall incidence of NBPP was 1.74 per 1000 live births. It has decreased in recent years.

INTERPRETATION

The incidence of NBPP is decreasing. Shoulder dystocia, macrosomia, maternal diabetes, instrumental delivery, and breech delivery are risk factors for NBPP. Caesarean section appears as a protective factor.

WHAT THIS PAPER ADDS

The overall incidence of neonatal brachial plexus palsy is 1.74 per 1000 live births. The incidence has declined significantly. Shoulder dystocia, macrosomia, maternal diabetes, instrumental delivery, and breech delivery are the main risk factors. Prevention is difficult owing to unpredictability and often labour-related risk.

A Study of the Diagnostic Accuracy of an Existing Multivariable Test to Predict Shoulder Dystocia

Objectives  To evaluate the diagnostic accuracy of a multivariable prediction model, the Shoulder Screen (Perigen, Inc.), and compare it with the American College of Obstetricians and Gynecologists (ACOG) guidelines to prevent harm from shoulder dystocia. Study Design  The model was applied to two groups of 199 patients each who delivered during a 4-year period. One group experienced shoulder dystocia and the other group delivered without shoulder dystocia. The model's accuracy was analyzed. The performance of the model was compared with the ACOG guideline. Results  The sensitivity, specificity, positive, and negative predictive values of the model were 23.1, 99.5, 97.9, and 56.4%, respectively. The sensitivity of the ACOG guideline was 10.1%. The false-positive rate of the model was 0.5%. The accuracy of the model was 61.3%. Conclusion  A multivariable prediction model can predict shoulder dystocia and is more accurate than ACOG guidelines.

An Update on the Management of Neonatal Brachial Plexus Palsy-Replacing Old Paradigms: A Review

IMPORTANCE

Neonatal brachial plexus palsy (NBPP) can result in persistent deficits for those who develop it. Advances in surgical technique have resulted in the availability of safe, reliable options for treatment. Prevailing paradigms include, "all neonatal brachial plexus palsy recovers," "wait a year to see if recovery occurs," and "don't move the arm." Practicing by these principles places these patients at a disadvantage. Thus, the importance of this review is to provide an update on the management of NBPP to replace old beliefs with new paradigms.

OBSERVATIONS

Changes within denervated muscle begin at the moment of injury, but without reinnervation become irreversible 18 to 24 months following denervation. These time-sensitive, irreversible changes are the scientific basis for the recommendations herein for the early management of NBPP and put into question the old paradigms. Early referral has become increasingly important because improved outcomes can be achieved using new management algorithms that allow surgery to be offered to patients unlikely to recover sufficiently with conservative management. Mounting evidence supports improved outcomes for appropriately selected patients with surgical management compared with natural history. Primary nerve surgery options now include nerve graft repair and nerve transfer. Specific indications continue to be elucidated, but both techniques offer a significant chance of restoration of function.

CONCLUSIONS AND RELEVANCE

Mounting data support both the safety and effectiveness of surgery for patients with persistent NBPP. Despite this support, primary nerve surgery for NBPP continues to be underused. Surgery is but one part of the multidisciplinary care of NBPP. Early referral and implementation of multidisciplinary strategies give these children the best chance of functional recovery. Primary care physicians, nerve surgeons, physiatrists, and occupational and physical therapists must partner to continue to modify current treatment paradigms to provide improved quality care to neonates and children affected by NBPP.

Risk factors for persistent disability in children with obstetric brachial plexus palsy

OBJECTIVE

Obstetric brachial plexus palsy (OBPP) at birth, is a serious neurologic injury that may lead to a long lasting disability. We aimed to examine the occurrence and risk factors associated with disability lasting >1 year.

STUDY DESIGN

A retrospective cohort study conducted between 1993 and 2012 included individuals with diagnosis of OBPP at birth. Affected individual's motor function was evaluated by a direct physical exam based on a muscle grading system of the limb, shoulder, elbow and hand. When not feasible a telephone questionnaire was used. Participants reported on activities of daily living, disability duration and any type of intervention. Stepwise logistic regression model was used to identify demographic and obstetric risk factors for disability lasting >1 year.

RESULTS

Of all 83 806 deliveries during this period, 144 OBPP cases were identified (1.7/1000). Of the 91 (63.2%) individuals located 42 (46.2%) were evaluated by a physical exam and 49 (53.8%) answered a telephone questionnaire. In 12 (13.2%) disability lasted >1 year. Significant predictors for disability lasting >1 year included birthweight >4 kg (P=0.02; odds ratio (OR) 6.17; 95% confidence interval (CI) 1.33-28.65) and younger maternal age (P=0.02; OR 0.84; 95% CI: 0.73-0.97). OBPP decreased 16% per 1 year increase in maternal age.

CONCLUSIONS

OBPP is a transient injury in most cases. Birthweight over 4 kg and younger maternal age maybe associated with disability lasting >1 year.

Peripartum and neonatal factors associated with the persistence of neonatal brachial plexus palsy at 1 year: a review of 382 cases

OBJECTIVE Neonatal brachial plexus palsy (NBPP) occurs due to the stretching of the nerves of the brachial plexus before, during, or after delivery. NBPP can resolve spontaneously or become persistent. To determine if nerve surgery is indicated, predicting recovery is necessary but difficult. Historical attempts explored the association of recovery with only clinical and electrodiagnostic examinations. However, no data exist regarding the neonatal and peripartum factors associated with NBPP persistence. METHODS This retrospective cohort study involved all NBPP patients at the University of Michigan between 2005 and 2015. Peripartum and neonatal factors were assessed for their association with persistent NBPP at 1 year, as defined as the presence of musculoskeletal contractures or an active range of motion that deviated from normal by > 10° (shoulder, elbow, hand, and finger ranges of motion were recorded). Standard statistical methods were used. RESULTS Of 382 children with NBPP, 85% had persistent NBPP at 1 year. A wide range of neonatal and peripartum factors was explored. We found that cephalic presentation, induction or augmentation of labor, birth weight > 9 lbs, and the presence of Horner syndrome all significantly increased the odds of persistence at 1 year, while cesarean delivery and Narakas Grade I to II injury significantly reduced the odds of persistence. CONCLUSIONS Peripartum/neonatal factors were identified that significantly altered the odds of having persistent NBPP at 1 year. Combining these peripartum/neonatal factors with previously published clinical examination findings associated with persistence should allow the development of a prediction algorithm. The implementation of this algorithm may allow the earlier recognition of those cases likely to persist and thus enable earlier intervention, which may improve surgical outcomes.