Studying the effects of McRoberts and neonate-focused maneuvers on the neonatal brachial plexus during shoulder dystocia.

Shoulder dystocia (SD) is an obstetric emergency in which the neonate's shoulder is impacted behind the symphysis pubis of the maternal pelvis. This is a highly unpredictable event, occurring in about 1.5% of vaginal deliveries. Some complications of SD for the neonate include injury to the brachial plexus (BP), humerus or clavicle fractures, and hypoxia. Clinicians then perform a series of sequential maneuvers to minimize injury to the neonate and mother. These maneuvers include the McRoberts maneuver, application of suprapubic pressure (SPP), rotational maneuvers, and delivery of the posterior arm. The maneuvers increase in invasiveness and skill level in the order in which they are attempted. The most common injury associated with SD is BP injury due to overstretch resulting from the impaction of the shoulder itself, forces applied by the mother and clinician, and/or the maneuvers to manage SD. The BP is a network of nerves beginning below the C5-T1 vertebrae and provides innervation to the arms. Neonatal brachial plexus palsy (NBPP) can result in temporary or permanent injury with loss of function of the arms. BP stretch cannot be studied in clinical deliveries due to ethical limitations, and therefore 3-dimensional computational models are utilized. Only a few such computational models are reported in the literature creating a gap to investigate them further. In this study, computational models of the neonate and maternal pelvis were developed using MADYMO, and maneuvers that are used to manage SD were simulated and their effects on BP were investigated. The models were created based on a 90th percentile neonate and a 50th percentile adult female pelvis. The BP was modeled as a 7.5 cm nonlinear spring with properties obtained from an in vitro study of the failure response of neonatal piglet BP nerves. The neonate model was subjected to forces applied by the mother due to contractions only and contractions with voluntary pushing, as well as clinician-applied traction (CAT) force to compare the resulting BP stretch. Then, maternal forces along with clinician-applied suprapubic pressures (SPP), and oblique and posterior arm maneuvers were simulated to investigate the resulting BP stretch. The simulations resulted in a decrease in CAT force and BP stretch with more advanced maneuvers such as oblique maneuver and delivery of the posterior arm. CAT force and BP stretch also decreased as SPP increased. A decrease in CAT force was observed as maternal forces increased with only a slight increase in BP stretch in all maneuvers. The trends found using these MADYMO models are valuable for determining the risk of BP injuries associated with SD maneuvers which are unable to be quantified clinically. These trends could help guide clinicians by effectively correlating magnitudes of CAT forces during maneuvers with BP stretch that are associated with SD, and also provide the data needed to create clinical training tools in the future.

Are there differences in mechanical fetal response between routine and shoulder dystocia deliveries?

Effect of clinician-applied maneuvers on brachial plexus stretch during a shoulder dystocia event: investigation using a computer simulation model

Objective The objective of the study was to determine how standard shoulder dystocia maneuvers affect delivery force and brachial plexus stretch. Study Design A 3-dimensional computer model of shoulder dystocia was developed, including both a fetus and a maternal pelvis. Application of suprapubic pressure, rotation of the infant's shoulders, and delivery of the posterior arm following shoulder dystocia were each modeled, and delivery force and brachial plexus stretch were predicted. Results Compared with lithotomy alone, all maneuvers reduced both the required delivery force and brachial plexus stretch. The greatest effect was seen with delivery of the posterior arm, which showed a 71% decrease in anterior nerve stretch (3.9% vs 13.5%) and an 80% decrease in delivery force. Conclusion The standard maneuvers met the objective of reducing the necessary delivery force compared with the lithotomy position alone. Brachial plexus stretch is also reduced when these maneuvers are used rather than continuing the delivery in lithotomy position.

Comparing mechanical fetal response during descent, crowning, and restitution among deliveries with and without shoulder dystocia

Prediction of brachial plexus stretching during shoulder dystocia using a computer simulation model

Effect of clinician applied maneuvers on fetal brachial plexus strain during shoulder dystocia delivery

The purpose of this computational study was to investigate the effects of neonate-focused clinical delivery maneuvers on brachial plexus (BP) during shoulder dystocia. During shoulder dystocia, the anterior shoulder of the neonate is obstructed behind the symphysis pubis of the maternal pelvis, postdelivery of the neonate's head. This is managed by a series of clinical delivery maneuvers. The goal of this study was to simulate these delivery maneuvers and study their effects on neonatal BP strain. Using madymo models of a maternal pelvis and a 90th-percentile neonate, various delivery maneuvers and positions were simulated including the lithotomy position alone of the maternal pelvis, delivery with the application of various suprapubic pressures (SPPs), neonate in an oblique position, and during posterior arm delivery maneuver. The resulting BP strain (%) along with the required maternal delivery force was reported in these independently simulated scenarios. The lithotomy position alone served as the baseline. Each of the successive maneuvers reported a decrease in the required delivery force and resulting neonatal BP strain. As the applied SPP force increased (three scenarios simulated), the required maternal delivery force and neonatal BP strain decreased. A further decrease in both delivery force and neonatal BP strain was observed in the oblique position, with the lowest delivery force and neonatal BP strain reported during the posterior arm delivery maneuver. Data obtained from the improved computational models in this study enhance our understanding of the effects of clinical maneuvers on neonatal BP strain during complicated birthing scenarios such as shoulder dystocia.

Shoulder dystocia is an uncommon and unpredictable obstetric emergency. It is associated with significant neonatal, maternal and medico-legal consequences. To ascertain the impact shoulder dystocia has on severe neonatal and maternal outcomes specific to the type of manoeuvre. This was a retrospective study of 48021 term singleton vaginal deliveries the Mater Mothers' Hospital in Brisbane between 2007 and 2015. Maternal and neonatal outcomes were compared between deliveries complicated by shoulder dystocia and those uncomplicated. Deliveries complicated by shoulder dystocia are associated with low Apgar scores (≤3) at five minutes (odds ratio (OR) 5.25, 95% CI 3.23-8.56, P<0.001), acidosis (OR 3.10, 95% CI 2.76-3.50, P<0.001), postpartum haemorrhage (OR 2.28, 95% CI 1.90-2.75, P<0.001) and perineal trauma (OR 1.92, 95% CI 1.54-2.39, P<0.001). Compared to McRoberts' manoeuvre and suprapubic pressure alone, the odds of serious neonatal outcome are increased with internal rotational manoeuvres (OR 3.82, 95% CI 2.54-5.74, P<0.001) and delivery of the posterior arm (OR 4.49, 95% CI 3.54-5.69, P<0.001). The OR of maternal injury is 2.07 (95% CI 1.77-2.45, P<0.001), 2.26 (95% CI 1.21-4.21, P<0.001) and 2.29 (95% CI 1.58-3.32, P<0.001) with McRoberts'/suprapubic pressure, internal rotation and posterior arm delivery, respectively. Brachial plexus injuries and fractures complicate 1.4 and 0.9% of deliveries, with the risk of injury increasing when greater than one manoeuvre is required. The risk of neonatal and maternal trauma is strongly associated with the number and types of manoeuvres. Given the associated implications, adequate antenatal counselling, simulation training and enhanced labour surveillance are essential.

Diabetes is associated with increased risk of stillbirth and shoulder dystocia. Compared with uncomplicated pregnancies, diabetic patients have a 4-6x risk of stillbirth and 2-3x risk of shoulder dystocia. A 34 yo G2P0010 presented with a 40+3 wga IUFD with nonstandard antenatal glucose screening. Admission labs included a hemoglobin A1c of 6.6. She had a vaginal delivery complicated by a 30-minute shoulder dystocia that was not relieved by McRoberts, suprapubic pressure, Rubin II, Wood's Screw, or posterior arm delivery. Nitroglycerine was administered, after which Wood's Screw was successful resulting in delivery of an infant weighing 4190 grams (85th percentile for gestational age). A 31 yo G1 presented with a 37+1 wga IUFD. Her 28 wga three-hour GTT was notable for an elevated value at one hour (216 mg/dL). Admission labs included a hemoglobin A1c of 6.6. She had a vaginal delivery complicated by a 30-minute shoulder dystocia that was relieved via posterior axillary sling after failure of McRoberts, suprapubic pressure, Rubin II, Wood's Screw, and Gaskin's, resulting in the delivery of an infant weighing 3590 g (92nd percentile for gestational age). We present two cases of severe shoulder dystocia in patients who both presented with term IUFD and diabetic-range hemoglobin A1c. There is minimal literature on diabetic patients with pregnancies affected by both stillbirth and shoulder dystocia. These cases underscore the importance of glucose screening and control to prevent catastrophic obstetric outcomes.

299: Association of maternal body mass index with shoulder dystocia management

Shoulder dystocia is an emergency and risky situation that most likely directly involves midwives. The aim of this study is to determine the effects of simulation training with a high fidelity mannequin on midwives' shoulder dystocia management. This study utilized a quantitative, quasi-experimental research design. No sample selection was made. The study included all midwives (n:16) working in the maternity unit of Manisa Province Hospital, Turkey. Management of shoulder dystocia was lectured both theoretically and practically, using a high fidelity simulation. Midwives' shoulder dystocia management skills and knowledge were evaluated before and after training using shoulder dystocia knowledge form and management skill checklist. There was a statistically significant increase in their shoulder dystocia management knowledge scores and management skills after simulation-based shoulder dystocia training (P < 0.05). Before the training, the midwives (62.5%) mostly used the McRoberts maneuver and suprapubic pressure as the primary interventions in shoulder dystocia management. After training, all the midwives were able to apply secondary maneuvers (Wood's or Rubin's maneuvres or posterior arm delivery) along with the primary maneuvers, in accordance with the shoulder dystocia management algorithm. Using a high fidelity simulation model in training increased midwives' shoulder dystocia management skills and knowledge.

Shoulder dystocia outcomes associated with structured prenatal counseling

A critical evaluation of the external and internal maneuvers for resolution of shoulder dystocia

To evaluate the different types and sequences of manoeuvres to overcome shoulder dystocia and the rates of associated fetal injury. Retrospective review. A university hospital. Pregnancies complicated with shoulder dystocia from 1995 to 2009. Cases were identified from the hospital electronic delivery records. The success rate between McRoberts' manoeuvre, rotational methods and posterior arm delivery, and the incidences of brachial plexus injury (BPI), clavicular fracture (CF) and humeral fracture (HF) according to the types and sequences of manoeuvres applied to overcome shoulder dystocia. Among 205 cases identified, McRoberts' manoeuvre was successful initially in 25% of cases, of which 7.8% suffered from BPI and 3.9% suffered from CF, but none had HF. In the failed cases, subsequent rotational methods and posterior arm delivery were similarly successful (72.0 versus 63.6%), whereas the former was associated with less BPI (4.4 versus 21.4%) and HF (1.1 versus 7.1%) despite similar risk of CF (5.6 versus 7.1%). The rotational methods were not associated with a higher fetal injury risk compared with McRoberts' manoeuvre. The remaining cases were managed by applying the third yet untried manoeuvre, and posterior arm delivery and rotational methods had similar success (77.1 versus 62.5%). The cumulative success rates after the second and the third manoeuvres were 79.0 and 94.6%, respectively. Following the failure of McRoberts' manoeuvre, subsequent application of rotational methods and posterior arm delivery have similarly high success rates but the former may be associated with less fetal injury.