Attacking the brachial plexus injury defense.

Some obstetrical experts say brachial plexus injuries in newborns can be caused by uterine contractions alone. This self-serving theory has little scientific support.

Obstetricians refer to the difficulty in delivering the shoulders of an infant as encountering shoulder dystocia. These deliveries must be handled with extreme care. The doctor or birth attendant must use one of several approved maneuvers to dislodge the shoulder that has become stuck behind the mother's pubic bone.(1)

When excessive force is used or lateral traction is applied to the infant's head to try to free the trapped shoulder, the brachial plexus network of nerves--which conduct signals from the brain to the shoulder, arm, and hand--can be injured. Lateral traction is one form of hyperextension of the head away from the shoulder.

In most cases, the injury is temporary, and the infant regains full movement of the arm. But some infants suffer permanent nerve injuries, including paralysis, loss of muscle control or feeling, and winging of or tendon damage to the shoulder blade.(2)

Trial lawyers who represent children who have suffered these injuries as a result of medical negligence must be familiar with the literature on the subject. Most of the older literature attributes brachial plexus injuries to excessive force and lateral traction.(3)

But in the past few years, some obstetrical researchers have published reports hypothesizing that these injuries are unpredictable and are caused by uterine contractions. One recent article, by Wisconsin obstetricians Herbert Sandmire and Robert DeMott, argues that the propulsive action of the uterus is so strong it can stretch the brachial plexus nerve, causing Erb's palsy, a weakness in the upper arm.(4) Another article, by obstetrician Bernard Gonik, undergraduate student Alberta Walker, and engineer Michele Grimm, includes a mathematical model claiming to support this theory.(5)

The lack of similar writings in recently published neurological and neonatal literature suggests that these articles, and others like them, may have been published merely to help doctors and birth attendants defend lawsuits. In fact, defendants are increasingly relying on these articles and the theories they propose.

Yet they can be attacked successfully, primarily because they are largely based on circumstantial evidence and subjective observations.

Cause and effect

Shoulder dystocia occurs most often with babies who are larger than normal at the time of delivery. Women who are obese or who develop gestational diabetes are at higher risk of this complication because they often give birth to babies who weigh more than average.

When shoulder dystocia occurs, the doctor or birth attendant should follow specific procedures. First, an episiotomy is performed to reduce resistance from the mother's pelvic floor. Then pressure is applied to the area above the mother's pubic bone while the doctor or birth attendant pulls down gently on the impacted shoulder.

The mother's legs may be flexed up and onto her abdomen, changing the position of the mother's pelvis relative to her spine. This posture, known as the McRoberts maneuver, widens the angle between the pelvis and the spine, allowing more room for the infant to pass through the birth canal.

The doctor or birth attendant also can use the Woods corkscrew maneuver to apply pressure to the front of the infant's shoulder to rotate and free it. Or a hand can be inserted into the birth canal, bending the fetal forearm and sweeping it across the chest and face to deliver the arm.

A brachial plexus injury can affect fetal nerves at the C5, C6, C7, C8, or T1 levels of the spinal cord. The nerve roots at C5, C6, and C7 are affected most often. The tearing of these nerves results in an inability to move the arm away from the body. An inability to rotate the arm internally, weakness of the upper arm, or a winging of the shoulder blade may result from nerve or muscle injury less severe than a complete tear of the nerves.

An injury to nerves at C8 results in weakness and/or paralysis of the forearm and wrist with a characteristic clawlike deformity of the hand. This is known as Klumpke's palsy. Horner's syndrome, symptoms of which include a drooping eyelid, may be present with Klumpke's palsy on the affected side due to the involvement of the sympathetic nerve fibers that traverse T1.(6)

An improperly handled delivery may also cause damage to the phrenic nerve, which enervates the diaphragm. As a result, a child may experience an increase in respiratory difficulties. Finally, an injury to T1 affects the use of the medial part, or underside, of the arm.

Flawed conclusions

In their article, Sandmire and DeMott argue that the propulsive action of the uterus is strong enough to stretch the nerves of the brachial plexus, causing the nerve damage at C5 and C6 that typically results in Erb's palsy. The authors drew their conclusions from the works of other researchers who reviewed the records of infants who were born with brachial plexus injuries and whose obstetricians or birth attendants did not document shoulder dystocia at the time of birth.(7) Because shoulder dystocia was not diagnosed in these cases, the authors concluded, the infants' brachial plexus injuries must have been caused by something else.

Yet closer examination of the materials Sandmire and DeMott relied on show why this conclusion is flawed. The presence or absence of shoulder dystocia in the cases reviewed was noted in the patients' records by the clinicians who delivered the infants, not by objective observers.

In one article that Sandmire and DeMott relied on, the researchers found that the mothers in cases where shoulder dystocia was diagnosed--and the mothers in cases where shoulder dystocia was not recorded but whose infants still suffered brachial plexus injuries--often had similar conditions, such as obesity, that put their babies at a higher risk of developing shoulder dystocia.(8) This finding suggests that many of these births may have been complicated by shoulder dystocia but that it simply was not recorded.

Another study confirms this. Researchers who reviewed the records of 26,033 vaginal births concluded that shoulder dystocia was underreported because the diagnosis relies on retrospective and subjective information provided by the clinician.(9)

Gonik and some of his colleagues in earlier works have suggested that subtle cases of shoulder dystocia can go unrecognized(10) and that clinicians may not note it in a patient's medical record.(11) Some researchers also have concluded that more brachial plexus injuries have occurred in cases where shoulder dystocia was not recognized and the appropriate maneuvers were not used, as compared to cases in which doctors correctly diagnosed shoulder dystocia and took the proper steps.(12)

Contrary to the conclusions reached by Sandmire and DeMott, these older articles indicate that the births of many injured infants probably were complicated by shoulder dystocia even though it was riot entered in the record.

Sandmire and DeMott also suggest that a rapid second stage of labor causes brachial plexus injuries.(13) The authors base this conclusion on another study that found that a rapid second stage may prohibit the fetal shoulders from entering the pelvic inlet at the proper oblique angle.(14) The researchers in that study had observed that 6.7 percent of the infants who were delivered precipitously experienced shoulder dystocia and of that group 31.8 percent suffered Erb's palsy.(15)

Contrary to Sandmire and DeMott's thesis, the logical conclusion from these data is not that a rapid second stage causes brachial plexus injuries. This study shows merely that there is an increased incidence of shoulder dystocia in cases involving a rapid second stage of labor, and that delivery of the infant using excessive force following the shoulder dystocia was the likely cause of the injuries.

Sandmire and DeMott also conclude that because some injuries involve the posterior arm when the anterior shoulder is impacted, uterine pressure on the posterior arm caused these injuries.(16) This conclusion is based on three articles written by expert witnesses who frequently testify for the defense in medical negligence cases. One article focuses on a single anecdotal case.

Several alternate theories can better explain these injuries. In some cases, it is likely that the posterior arm was forcefully maneuvered because the anterior arm could not be reached. Or the injuries may have been caused by upward rather than downward traction on the impacted shoulder. And, of course, in a few cases, the records may have been falsified.

Sandmire and DeMott also conclude that injuries can occur when obstetrical maneuvers like placing the mother in the McRoberts position are employed.(17) But again, this conclusion is unsupported. The likely cause of injury is excessive traction applied either before or during the maneuver.

New math

Based on the hypothesis that brachial plexus injuries can occur in births uncomplicated by shoulder dystocia, Gonik, Walker, and Grimm recently attempted to create a mathematical model to show that these injuries could be caused by compression due to uterine forces on brachial plexus nerves.(18) In developing the model to simulate the forces applied to the fetus by the mother and the physician during labor, the researchers used data from a 1960 study that measured the amount of pressure contractions exerted on the largest part of the fetal head during the first and second stages of labor. That study examined only 36 patients.(19)

From these data, Gonik and his colleagues estimated the amount of pressure that would be applied against the neck of a fetus whose passage was blocked by shoulder dystocia. They attempted to hypothesize force to the part of the fetal neck overlying the roots of the brachial plexus, from a study that measures maternal forces applied only to the large part of the fetal head.(20) These two pressures are not likely to be similar.

The authors say their model likens the fetus and uterus to the hard surface of a piston.(21) The authors readily admit that the model does not take into account how soft tissue would absorb and dissipate the force of uterine contractions.(22)

Additionally, the authors' model fails to account for the resistance supplied by the sacrum, or tailbone, during delivery. As a result, the model predicts forces on the impacted shoulder that are almost two times too high.(23)

Following the publication of the Gonik, Walker, and Grimm article, obstetricians Robert Allen and Stuart Edelberg wrote a letter to the American Journal of Obstetrics and Gynecology detailing the engineering flaws in the proposed mathematical model.(24) In addition to pointing out that the model incorrectly doubles the load of maternal forces placed on the impacted shoulder, Allen and Edelberg noted it violates Newton's equilibrium law.

Moreover, the article never passed engineering peer review and could not have been published in an engineering journal. Yet earlier articles written by Gonik and Allen showing that a great amount of force used by a doctor or delivery attendant resulted in injury to the fetal brachial plexus did pass engineering peer review.

Allen's and Edelberg's criticism of the article is supported by the testimony of one of its authors, Michele Grimm, in a deposition taken earlier this year.(25) In that deposition, Grimm, a bioengineer at Wayne State University in Detroit, revealed that the mathematical model was created by another of the article's authors, Alberta Walker, who is one of Grimm's undergraduate students.(26)

Grimm confirms in her deposition that Newton's equilibrium law was not met by the model because it did not take into account moment equilibrium.(27) "Moment equilibrium" is an engineering term; a moment is force that is applied at some distance from the center of rotation.(28)

Grimm admitted that there is no medical literature that says compression from maternal forces results in permanent brachial plexus injuries--and that an avulsion, or complete tear, of the brachial plexus nerves from the spinal cord is unlikely to be caused by maternal forces of compression.(29)

Forceful facts

The details of a delivery are recorded after it is over and the outcome is known. Some obstetricians believe they can hide their negligence and better defend themselves by leaving certain facts, like the occurrence of shoulder dystocia, out of the record.

In some cases where there is no record of shoulder dystocia, parents or other people who witnessed a delivery in cases we have handled have said or told us they knew from the discussion and action in the delivery room that the infant's shoulder had become stuck in the birth canal. Occasionally, a videotape of a delivery will record an undocumented case of shoulder dystocia.

Some doctors and birth attendants are not aware that shoulder dystocia has occurred. They may experience difficulty with the delivery but not recognize or label the problem as shoulder dystocia. In these cases, the attendant may inadvertently apply increasing amounts of lateral traction to the fetal head.(30)

Therefore, researchers should not automatically conclude that an infant who suffered a brachial plexus injury during a birth with no record of shoulder dystocia must have been injured by something other than a mismanaged attempt to free a stuck shoulder. As researchers have noted, the reporting of shoulder dystocia varies from 0.6 percent to 2.8 percent in nonbreech vaginal deliveries.(31)

Even when all objective evidence shows that a birth was not complicated by shoulder dystocia, a mishandled delivery can still result in brachial plexus injuries. For example, a doctor or birth attendant can apply excessive force with downward traction or lateral traction in other situations, such as when the mother is unable to push.

The worse the injury to the child, the more likely that it was caused by excessive force on the part of the obstetrician or delivery attendant. For example, if a child's nerves are found to be avulsed in a subsequent surgery for repair, it is virtually certain that the injury was caused by obstetrical negligence. No reported cases--or even any theoretical articles--attribute such a devastating injury to the natural forces of labor, as engineer Grimm confirmed in her recent deposition.

Fragile foundation

No studies conclusively show that brachial plexus injuries are caused by anything other than excessive force or lateral neck traction, whether these are applied to free a blocked shoulder or for some other reason. A malpractice defense based on the recent nonscientific, subjective articles saying otherwise is built on pillars of sand.

Sound reason and the weight of the evidence are on the side of plaintiff lawyers in these cases. They should not hesitate to use both to bring the foundations of these misplaced and self-serving theories tumbling to the ground.

Prepare your obstetrical negligence case with documents available from the ATLA Exchange

The documents listed below and many others on topics pertaining to medical negligence litigation are available from the ATLA Exchange. For more information, visit the Exchange Web site at http://exchange.atla.org, or contact the Exchange by phone at [phone] or by fax at [phone].

Brown v. HCA Highland Hospital Services. The plaintiffs' supplemental petition on breach of contract, damages, attorney fees, medical negligence, and loss of consortium in a case in which they alleged hospital liability for failure to monitor fetal distress. (No. LR2499.)

Hull v. Cohen. The defendant's deposition in a case alleging use of excessive force in a delivery. (No. LR379.)

Lopez v. Mission Hospital. The deposition of the defendant obstetrician's expert in a case alleging mismanagement of a prolapsed umbilical cord. (No. LR2731.)

Marlin v. Murdoch. The plaintiffs' trial brief in a case alleging negligent delivery of an infant when shoulder dystocia was encountered. (No. LR2109.)

Murdock v. Texarkana Memorial Hospital. The charge to the jury and the plaintiffs' amended petition in a case alleging failure to suction an infant. (No. LR2112.)

Pearston v. St. John & West Shore Hospital. The plaintiffs' trial brief alleging failure to recognize fetal distress and discontinue Pitocin. (No. LR1972.)

Pisco v. Maternity Infant Care Family Planning Project. The plaintiffs obstetrical expert's trial testimony in a case alleging negligent failure to rule out placenta previa or timely administer tocolytic drugs. (No. LR458.)

Reece v. Jackson. An expert's deposition in a case alleging failure to diagnose that an infant would be macrosomic. (No. LR2026.)

Rodriguez v. Mother Frances Hospital. The plaintiffs' second and fourth amended petitions in a case alleging failure to timely perform a cesarean section. (No. EX1444.)

Romero v. Kaplan. The plaintiffs' motion to preclude the testimony of the defendant's vocational rehabilitation expert and the depositions of that expert and the defendant in a case in which the plaintiffs alleged failure to diagnose, and negligent delivery of, a macrosomic infant. (No. LR397.)

Sargood v. Clements & Ashmore, PA. The plaintiffs' complaint in a case alleging improper monitoring and failure to perform a timely cesarean section. (No. LR2710.)

Wade v. United States. The plaintiffs' trial brief alleging that a military obstetrician had negligently failed to properly manage a high-risk twin pregnancy. (No. EX1394.)

Wingo v. Rockford Memorial Hospital. Expert depositions in a case alleging improper discharge of a pregnant woman with ruptured membranes. (No. LR538.)

L2601MMA 

Notes

(1.) JAMES J. NOCON & LES WEISBROD, Shoulder-Dystocia, in OPERATIVE OBSTETRICS 339, 33953 (John Patrick O'Grady & Martin L. Gimovsky eds., 1995).

(2.) Id. at 341.

(3.) American College of Obstetricians and Gynecologists, Intrapartum Management, in PRECIS: AN UPDATE IN OBSTETRICS & GYNECOLOGY 85, 95-96 (1998).

(4.) Herbert F. Sandmire & Robert K. DeMott, Erb's Palsy: Concepts of Causation, 95 OBSTETRICS & GYNECOLOGY 941, 941 (2000).

(5.) Bernard Gonik et al., Mathematic-Modeling of Forces Associated with Shoulder Dystocia: A Comparison of Endogenous and Exogenous Sources, 182 AM. J. OBSTETRICS & GYNECOLOGY 689 (2000).

(6.) NOCON & WEISBROD supra note 1, at 341.

(7.) See Robert B. Gherman et al., Spontaneous Vaginal Delivery: A Risk Factor for Erb's Palsy? 178 AM. J. OBSTETRICS & GYNECOLOGY 423, 423 (1998); Robert B. Gherman et al., Brachial-Plexus Palsy Associated with Cesarean Section:An In Utero Injury? 177 AM. J. OBSTETRICS & GYNECOLOGY 1162, 1163 (1997); Raymond J. Jennett et al., Brachial Plexus Palsy:An Old Problem Revisited, 166 AM. J. OBSTETRICS & GYNECOLOGY 1673, 1673-74 (1992).

(8.) Gherman et al., Spontaneous Vaginal-Delivery: A Risk Factor for Erb's Palsy?, supra note 7, at 424.

(9.) Bernard Gonik et al., Shoulder Dystocia Recognition: Differences in Neonatal Risks for Injury, 8 AM. J. PERINATOLOGY 31, 31, 33-34 (1991).

(10.) See id. at 33.

(11.) See id. at 34.

(12.) Susan J. Gross et al., Shoulder Dystocia: Predictors and Outcome, 156 AM. J. OBSTETRICS & GYNECOLOGY 334, 336 (1987).

(13.) Sandmire & DeMott, supra note 4, at 941.

(14.) David B. Acker et al., Risk Factors for Erb-Duchenne Palsy, 71 OBSTETRICS & GYNECOLOGY 389, 392 (1988).

(15.) Id. at 390.

(16.) Sandmire & DeMott, supra note 4, at 941; see also Gherman, Spontaneous Vaginal Delivery, supra note 7, at 425; Gary D.V. Hankins & Steven L. Clark, Brachial Plexus Palsy Involving the Posterior Shoulder at Spontaneous Vaginal Delivery, 12 AM. J. PERINATOLOGY 44 (1995); Joseph G. Ouzounian et al., Permanent Erb Palsy: A Traction-Related Injury? 89 OBSTETRICS & GYNECOLOGY 139, 139 (1997).

(17.) Sandmire & DeMott, supra note 4, at 941 (citing Robert B. Gherman et al., Obstetric Maneuvers for Shoulder Dystocia and Associated Fetal Morbidity, 178 AM. J. OBSTETRICS & GYNECOLOGY 1126, 1128-29 (1998)).

(18.) Gonik et al., supra note 5.

(19.) Lennart Lindgren, The Causes of Foetal Head Moulding in Labour, 39 ACTA OBSTETRICIA & GYNECOLOGICA SCANDINAVICA 46, 61 (1960).

(20). See Robert H. Allen & Stuart C. Edelberg, A Problematic Model to Predict Intrauterine Forces During Shoulder Dystocia, 184 AM. J. OBSTETRICS & GYNECOLOGY 514 (2001).

(21.) Gonik et al., supra note 5, at 690.

(22.) Id.

(23.) Allen & Edelberg, supra note 20.

(24.) Id.

(25.) Deposition of Michelle Grimm, Bajic v. Patel, No. 97-L-3609 (Ill., Cook County Cir. Ct. Jan. 17, 2001).

(26.) Id. at 27-28.

(27.) Id. at 78-80.

(28.) Id. at 78.

(29.) Id. at 40-41.

(30.) Bernard Gonik et al., Objective Evaluation of the Shoulder Dystocia Phenomenon: Effect of Maternal Pelvic Orientation on Force Reduction, 74 OBSTETRICS & GYNECOLOGY 44, 47 (1989).

(31.) Barbara B. Bennett, Shoulder Dystocia: An Obstetric Emergency, 26 OBSTETRICS & GYNECOLOGY CLINICS N. AM. 445, 445 (1999).

Les Weisbrod is a partner with Morgan & Weisbrod in Dallas. Pat Stein is a law clerk with the firm.