Design of a new instrumented forceps: application to safe obstetrical forceps blade placement.

Today, medical simulators are increasingly gaining appeal in clinical settings. In obstetrics childbirth simulators provide a training and research tool for comparing various techniques that use obstetrical instruments or validating new methods. Especially in the case of difficult deliveries, the use of obstetrical instruments-such as forceps, spatulas, and vacuum extractors-has become essential. However, such instruments increase the risk of injury to both the mother and fetus. Only clinical experience acquired in the delivery room enables health professionals to reduce this risk. In this context, we have developed, in collaboration with researchers and physicians, a new type of instrumented forceps that offers new solutions for training obstetricians in the safe performance of forceps deliveries. This paper focuses on the design of this instrumented forceps, coupled with the BirthSIM simulator. This instrumented forceps allows to study its displacement inside the maternal pelvis. Methods for analyzing the operator repeatability and to compare forceps blade placements to a reference one are developed. The results highlight the need of teaching tools to adequately train novice obstetricians.

A new obstetric forceps for the training of junior doctors: a comparison of the spatial dispersion of forceps blade trajectories between junior and senior obstetricians.

OBJECTIVE: The purpose of this study was to create a new instrument for the training of doctors in the use of forceps and to compare the trajectories of forceps blades between junior and senior obstetricians. STUDY DESIGN: We equipped a simulator and forceps with spatial location sensors. The head of the fetus was in an occipitoanterior location, at a "+5" station. Forceps blade trajectories were analyzed subjectively with the 3-dimensional spatial graph and objectively based on 3 points of special interest. Each obstetrician performed 4 forceps blades placements. We compared the trajectories of junior and senior obstetricians. RESULTS: For senior operators, spatial dispersion was "excellent," "very good," or "good" in 92% of cases, whereas this was the case for only 38% of junior doctors (92% vs 38%; P < .001). CONCLUSION: A new instrument has been designed to demonstrate the trajectory of forceps blades during application in a simulator. The instrument captures the difference in experience between senior and junior clinicians.

Birth simulator: reliability of transvaginal assessment of fetal head station as defined by the American College of Obstetricians and Gynecologists classification.

OBJECTIVE: This study was undertaken to investigate the reliability of transvaginal assessment of fetal head station by using a newly designed birth simulator. STUDY DESIGN: This prospective study involved 32 residents and 25 attending physicians. Each operator was given all 11 possible fetal stations in random order. A fetal head mannequin was placed in 1 of the 11 American College of Obstetricians and Gynecologists (ACOG) stations (-5 to +5) in a birth simulator equipped with real-time miniaturized sensor. The operator then determined head position clinically using the ACOG classification. Head position was described as: (1) "engaged" or "nonengaged" (engagement code); (2) "high," "mid," "low," or "outlet" (group code); and (3) according to the 11 ACOG ischial spine stations (numerical code). Errors were defined as differences between the stations given by the sensor and by the operator. We determined the error rates for the 3 codes. RESULTS: "Numerical" errors occurred in 50% to 88% of cases for residents and in 36% to 80% of cases for attending physicians, depending on the position. The mean "group" error was 30% (95% CI 25%-35%) for residents and 34% (95% CI 27%-41%) for attending physicians. In most cases (87.5% for residents and 66.8% for attending physicians) of misdiagnosis of "high" station, the "mid" station was retained. Residents and attending physicians made an average of 12% of "engagement" errors, equally distributed between false diagnosis of engagement and nonengagement. CONCLUSION: Our results show that transvaginal assessment of fetal head station is poorly reliable, meaning clinical training should be promoted. The choice not to perform vaginal delivery when the fetus is in the "mid" position strongly decreases the risk of applying instruments on an undiagnosed "high" station. Conversely, obstetricians who perform only "low" operative vaginal deliveries also deliver unrecognized "mid" station fetuses. Therefore, residency programs should offer training in "mid" pelvic operative vaginal deliveries. Birth simulators could be used in training programs.

Comparison of "instrument-associated" and "spontaneous" obstetric depressed skull fractures in a cohort of 68 neonates.

OBJECTIVE: A depressed skull fracture is an inward buckling of the calvarial bones and is referred to as a "ping-pong" fracture. This study aimed to look at differences between "spontaneous" and "instrument-associated" depressed skull fractures. STUDY DESIGN: This retrospective, case-control analysis included every neonate who was admitted with a depressed skull fracture between 1990 and 2000. Cases after a spontaneous vaginal delivery, elective cesarean delivery, or cesarean delivery that was performed during labor without previous instrument use were classified as "spontaneous" (n = 18 cases). Cases after a delivery in which forceps or a vacuum cup had been used either successfully or unsuccessfully were classified as "instrument-associated" (n = 50 cases). Continuous data were analyzed with 2-tailed unpaired t tests; chi 2 analysis was used for nominal data. A probability value of <.05 was considered statistically significant. RESULTS: Fifty depressed skull fractures were associated with an instrument delivery, and 18 depressed skull fractures were classified as "spontaneous." The only obstetric parameter that differed significantly between the 2 groups was the length of the active phase. Among the 68 neonates, 15 neonates underwent prolonged second stage, forceps or manual head rotation, or forceps use during elective cesarean delivery. All "instrument-associated" cases were caused by forceps application or sequential instrument use; depressed skull fractures never occurred after isolated vacuum extraction. Every type of forceps was involved. Intracranial lesions were significantly more frequent in the instrument-associated group (30% vs 0%; P = .02). Two infants sustained persistent severe motor disabilities. CONCLUSION: Depressed skull fractures occur in the setting of spontaneous and operative deliveries, although the incidence is higher in the latter case. Depressed skull fractures that are associated with instrumental deliveries are significantly more likely to be associated with intracranial lesions. Persistent disabilities are rare.