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Letters to the Editor to:

Scientific Articles:
Susan L. Foad, Charles T. Mehlman, and Jun Ying
The Epidemiology of Neonatal Brachial Plexus Palsy in the United States
J Bone Joint Surg Am 2008; 90: 1258-1264 [Abstract] [Full text] [PDF]
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Electronic letters published:

[Read Letter to the Editor] Dr. Foad and colleagues respond to Dr. Alfonso
Susan L Foad, MPH, Charles T. Mehlman, DO, MPH and Jun Ying, PhD   (24 September 2008)
[Read Letter to the Editor] Causes and Factors Involved In Neonatal Brachial Plexus Palsy
Israel Alfonso, Andrew E. Price, John A. I. Grossman   (26 August 2008)

Dr. Foad and colleagues respond to Dr. Alfonso 24 September 2008
Previous Letter to the Editor Top
Susan L Foad, MPH,
Outcomes Coordinator
Cincinnati Children's Hospital Medical Center,
Charles T. Mehlman, DO, MPH and Jun Ying, PhD

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Re: Dr. Foad and colleagues respond to Dr. Alfonso

susan.foad{at}cchmc.org Susan L Foad, MPH, et al.

We thank Dr. Alfonso for his comments and we are pleased to respond. Following in the footsteps of our colleagues at The Texas Scottish Rite Hospital (1), we prefer to use the term "neonatal brachial plexus palsy" to describe such brachial plexus injuries in infants. The term “obstetrical brachial plexus palsy” is an out dated term that unfairly implies causation. Just as “Pediatrician hip dysplasia” is a term that would never be accepted to describe developmental dysplasia of the hip, we feel that we are at a point in time where we should no longer accept “obstetrical brachial plexus palsy.” We feel that our paper further supports this contention because the majority (54%) of infants with documented brachial plexus injuries had no identifiable risk factors

Cases of neonatal brachial plexus palsy were identified using ICD-9 code(2), age of admission and type of admission from the Kids’ Inpatient Data Base (KIDS). The ICD-9 code 767.6 was defined as an injury to the brachial plexus, palsy or paralysis: brachial, Erb (Duchenne). Tumors, inflammation, or nondelivery–related trauma were not specified in the KIDS and hence could not be excluded in analyses. Nevertheless, we believe that they were rare cases and that their potential effects on our results would be trivial.

Dr. Alfonso, has identified a limitation of utilizing a large national database. Data analysis is limited to variables that are collected in the database. Risk factors identified in our study from KIDS were limited only to variables contained in the infant discharge summary. Data regarding length of labor, space abnormalities, uterine malformation, etc would be reported in the mother’s discharge data and this data is not available from this database.

1. Smith NC, Rowan P, Benson LJ, Ezaki M, Carter PR. Neonatal Brachial Plexus Palsy. Outcome Of Absent Biceps Function At Three Months Of Age. JBJS-A. 2004:86-A:2163-70.

2. Hart AC, Hopkins CA ,eds. ICD-9-CM Expert for Physicians Volume 1 & 2. Ingenix; 2005.
Causes and Factors Involved In Neonatal Brachial Plexus Palsy 26 August 2008
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Israel Alfonso,
Pediatric Neurologist
Miami Children's Hospital and Florida International University,
Andrew E. Price, John A. I. Grossman

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Re: Causes and Factors Involved In Neonatal Brachial Plexus Palsy

ialfonso{at}pediatricneuro.com Israel Alfonso, et al.

To the Editor:

We read with interest the article by Foad, et al(1). The authors appear to use the term neonatal brachial plexus palsy as a synonym for obstetrical brachial plexus palsy or brachial plexus birth injury. Were there any nonobstetrical causes of brachial plexus palsy, such as brachial plexus tumors, inflammation, or nondelivery-related trauma in their population?

The article states that 54% of children with neonatal brachial plexus palsy had no known risk factors for this condition, yet the authors limited the studied variables to factors related to the magnitude of the stretching force acting upon the brachial plexus at the time of delivery: shoulder dystocia, instrumented delivery, breech delivery, cesarean delivery, an exceptionally large baby (an infant weighing >4.5 kg), heavy for dates (a fetus or infant larger for dates regardless of period of gestation) and twin or multiple birth-mate babies. This approach reduces the percentage of patients with known risk factors by ignoring conditions such as ultrashort second stage of labor, supracostoclavicular space abnormalities, conditions that limit arm motility during late gestation, maternal uterine malformations, and familial predisposition.(2-4). Can these risk factors be retrospectively analyzed in the study population?

At our program we have taken a wider approach to the search for possible risk factors based on the following consideration and formula. The probability (p) of an obstetrical brachial plexus injury (obpi) is directly proportional to the magnitude of stretching force, which consists of the sum of the propulsive and traction forces exerted on the brachial plexus (pf + tf), the acceleration of the stretching force (a), and the parallelism (cos of ∠) between the vector of the stretching force and the axis of the most vulnerable brachial plexus segment (@ bp); and inversely proportional to the resistance (r) of the brachial plexus nerve bundles (n), shoulder girdle muscles (m) , joints (j) and bones (b).

p of obpi = (pf + tf) a (cos of ∠) @ bp / r (n + m + j + b)

This approach has led to the discovery of risk factors not related to the magnitude of the stretching force in some of our patients.

The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated.

REFERENCES

1.Susan L. Foad, Charles T. Mehlman, and Jun Ying The Epidemiology of Neonatal Brachial Plexus Palsy in the United States J Bone Joint Surg Am 2008; 90: 1258-1264.

2. Sandmire HF, DeMott RK. Erb’s palsy causation: A historical perspective. Birth. 2002;29 (1):52-54.

3. Becker MH, Lassner F, Bahm J, Ingianni G, Pallua N. The cervical rib. A predisposing factor for obstetric brachial plexus lesions. J Bone Joint Surg Br. 2002;84(5):740-743.

4. Alfonso I, Diaz-Arca G, Alfonso DT, Shuhaiber HH, Papazian O, Price AE, Grossman JA. Fetal deformations: A risk factor for obstetrical brachial plexus palsy? Pediatr Neurol. 2006;35(4):246-249.