Performance of microvascular anastomosis with a new robotic visualization system: proof of concept.

Microvascular procedures require visual magnification of the surgical field, e.g. by a microscope. This can be accompanied by an unergonomic posture with musculoskeletal pain or long-term degenerative changes as the eye is bound to the ocular throughout the whole procedure. The presented study describes the advantages and drawbacks of a 3D exoscope camera system. The RoboticScope®-system (BHS Technologies®, Innsbruck, Austria) features a high-resolution 3D-camera that is placed over the surgical field and a head-mounted-display (HMD) that the camera pictures are transferred to. A motion sensor in the HMD allows for hands-free change of the exoscope position via head movements. For general evaluation of the system functions coronary artery anastomoses of ex-vivo pig hearts were performed. Second, the system was evaluated for anastomosis of a radial-forearm-free-flap in a clinical setting/in vivo. The system positioning was possible entirely hands-free using head movements. Camera control was intuitive; visualization of the operation site was adequate and independent from head or body position. Besides technical instructions of the providing company, there was no special surgical training of the surgeons or involved staff upfront performing the procedures necessary. An ergonomic assessment questionnaire showed a favorable ergonomic position in comparison to surgery with a microscope. The outcome of the operated patient was good. There were no intra- or postoperative complications. The exoscope facilitates a change of head and body position without losing focus of the operation site and an ergonomic working position. Repeated applications have to clarify if the system benefits in clinical routine.

Evaluation of a curved surgical prototype in a human larynx.

PURPOSE: It is not always possible to create linear access to the larynx using a rigid operating laryngoscope for microlaryngoscopy. In this study, we evaluate the usability of a novel curved surgical prototype with flexible instruments for the larynx (sMAC) in a simulation dummy and human body donor. METHODS: In a user study (n = 6), head and neck surgeons as well as medical students tested the system for visualization quality and accessibility of laryngeal landmarks on an intubation dummy and human cadaver. A biopsy of the epiglottis was taken from the body donor. Photographic and time documentation was carried out. RESULTS: The sMAC system demonstrated general feasibility for laryngeal surgery. Unlike conventional microlaryngoscopy, all landmarks could be visualized and manipulated in both setups. Biopsy removal was possible. Visibility of the surgical field remained largely unobstructed even with an endotracheal tube in place. Overall handling of the sMAC prototype was satisfactorily feasible at all times. CONCLUSION: The sMAC system could offer an alternative for patients, where microlaryngoscopy is not applicable. A clinical trial has to clarify if the system benefits in clinical routine.

[Robot-assisted head and neck surgery]. / Robotik in der Kopf-Hals-Chirurgie.

Robot-assisted surgery (RAS) has already been approved for several clinical applications in head and neck surgery. In some Anglo-American regions, RAS is currently the common standard for treatment of oropharyngeal diseases. Systematic randomized studies comparing established surgical procedures with RAS in a large number of patients are unavailable so far. Experimental publications rather describe how to reach poorly accessible anatomical regions using RAS, or represent feasibility studies on the use of transoral robotic surgery (TORS) in established surgical operations. With general application of RAS in clinical practice, the question of financial reimbursement arises. Furthermore, the technical applications currently on the market still require some specific improvements for routine use in head and neck surgery.

Economic risk factors for HIV infection among women in rural Haiti: implications for HIV prevention policies and programs in resource-poor settings.

AIMS: The goals of this study were to (1) estimate the prevalence of HIV infection among women accessing services at a women's health center in rural Haiti and (2) to identify economic risk factors for HIV infection in this population. METHODS: Women who accessed healthcare services at this center between June 1999 and December 2002 were recruited to participate. The analysis was based on data from a case-control study of sexually transmitted diseases (STDs) in rural Haiti. HIV prevalence in the study population was 4%. RESULTS: In multivariate analyses, partner occupation was associated with HIV infection in women, with mechanic (OR 9.0, 95% CI 1.8-45) and market vendor (OR 4.2, 95% CI 1.6-11) reflecting the strongest partner occupational risk factors. Partner's occupation as a farmer reduced the risk of infection in women by 60% (95% CI 0.14-1.1). Factors indicating low socioeconomic status (SES), such as food insecurity (OR 2.0, 95% CI 0.75-5.6) and using charcoal for cooking (OR 1.7, 95% CI 0.72-3.8) suggested an association with HIV infection. CONCLUSIONS: Given pervasive gender inequality in Haiti, women's economic security often relies on their partners' income earning activities. Our findings show that although factors reflecting poverty are associated with HIV-positive status, stronger associations are observed for women whose partners indicated a more secure occupation (e.g., mechanic or market vendor). Policies and programs that expand access to education and economic opportunities for women and girls may have long-term implications for HIV prevention in Haiti and other resource-poor settings.

A multicenter controlled trial of fetal pulse oximetry in the intrapartum management of nonreassuring fetal heart rate patterns.

OBJECTIVE: Recent developments permit the use of pulse oximetry to evaluate fetal oxygenation in labor. We tested the hypothesis that the addition of fetal pulse oximetry in the evaluation of abnormal fetal heart rate patterns in labor improves the accuracy of fetal assessment and allows safe reduction of cesarean deliveries performed because of nonreassuring fetal status. STUDY DESIGN: A randomized, controlled trial was conducted concurrently in 9 centers. The patients had term pregnancies and were in active labor when abnormal fetal heart rate patterns developed. The patients were randomized to electronic fetal heart rate monitoring alone (control group) or to the combination of electronic fetal monitoring and continuous fetal pulse oximetry (study group). The primary outcome was a reduction in cesarean deliveries for nonreassuring fetal status as a measure of improved accuracy of assessment of fetal oxygenation. RESULTS: A total of 1010 patients were randomized, 502 to the control group and 508 to the study group. There was a reduction of >50% in the number of cesarean deliveries performed because of nonreassuring fetal status in the study group (study, 4. 5%; vs. control, 10.2%; P =.007). However, there was no net difference in overall cesarean delivery rates (study, n = 147 [29%]; vs. control, 130 [26%]; P = .49) because of an increase in cesarean deliveries performed because of dystocia in the study group. In a blinded partogram analysis 89% of the study patients and 91% of the control patients who had a cesarean delivery because of dystocia met defined criteria for actual dystocia. There was no difference between the 2 groups in adverse maternal or neonatal outcomes. In terms of the operative intervention for nonreassuring fetal status, there was an improvement in both the sensitivity and the specificity for the study group compared with the control group for the end points of metabolic acidosis and need for resuscitation. CONCLUSION: The study confirmed its primary hypothesis of a safe reduction in cesarean deliveries performed because of nonreassuring fetal status. However, the addition of fetal pulse oximetry did not result in an overall reduction in cesarean deliveries. The increase in cesarean deliveries because of dystocia in the study group did appear to result from a well-documented arrest of labor. Fetal pulse oximetry improved the obstetrician's ability to more appropriately intervene by cesarean or operative vaginal delivery for fetuses who were actually depressed and acidotic. The unexpected increase in operative delivery for dystocia in the study group is of concern and remains to be explained.

Search for neutrino oscillations at the palo verde nuclear reactors

We report on the initial results from a measurement of the antineutrino flux and spectrum at a distance of about 800 m from the three reactors of the Palo Verde Nuclear Generating Station using a segmented gadolinium-loaded scintillation detector. We find that the antineutrino flux agrees with that predicted in the absence of oscillations excluding at 90% C.L. nu;(e)-nu;(x) oscillations with Deltam(2)>1.12x10(-3) eV(2) for maximal mixing and sin (2)2straight theta>0.21 for large Deltam(2). Our results support the conclusion that the atmospheric neutrino oscillations observed by Super-Kamiokande do not involve nu(e).

In utero repair of myelomeningocele: a comparison of endoscopy and hysterotomy.

OBJECTIVE: To compare endoscopic coverage of myelomeningocele with a maternal split-thickness skin graft in utero to definitive neurosurgical closure through a hysterotomy. METHODS: Four fetuses with isolated myelomeningocele underwent endoscopic coverage of the defect with a maternal split-thickness skin graft in a CO(2) environment at 22-24 weeks' gestation. Subsequently, 4 fetuses underwent standard neurosurgical closure of their myelomeningoceles at 28-29 weeks' gestation. RESULTS: The mean operating time for the endoscopic procedures was 297 +/- 69 min. Two fetal losses occurred as a result of chorioamnionitis and placental abruption, respectively. A third baby delivered at 28 weeks' gestation after prolonged disruption of the membranes. The 2 survivors required standard closure of the myelomeningocele after delivery. The mean operating time for the hysterotomy procedures was 125 +/- 8 min. No mortality occurred, and all the infants delivered between 33 and 36 weeks with well-healed myelomeningocele scars. At present, the functional levels of all infants approximate the anatomical levels of the lesions. CONCLUSION: With current technology, in utero repair of congenital myelomeningocele through a hysterotomy appears to be technically superior to procedures performed endoscopically.

Electronic fetal heart rate monitoring: early neonatal outcomes associated with normal rate, fetal stress, and fetal distress.

OBJECTIVE: The purpose of this study was to test the ability of a clearly defined classification system for electronic fetal heart rate monitoring to predict early neonatal outcome. STUDY DESIGN: All labors of women with singleton pregnancies > or = 32 weeks' gestation electronically monitored at 2 institutions were examined. Tracings in the final hour before delivery were defined as normal, fetal stress, or fetal distress. After delivery, Apgar scores, cord blood gas values, and admission to the neonatal intensive care unit were examined as measures of early neonatal outcome. RESULTS: Among the 898 patients who qualified for study, 627 (70%) had tracings classified as normal, 263 (29%) had tracings classified as fetal stress, and 8 (1%) had tracings classified as fetal distress. There was a significant worsening of neonatal outcome across these 3 groups with regard to depressed Apgar scores 1 minute (5.1%, 18.3%, and 75.0%; P <.05), depressed Apgar scores at 5 minutes (1.0%, 3.8%, and 37.5%; P <.05), and admission to the neonatal intensive care unit (5.6%, 10.6%, and 37.5%; P <.05). There was also a progressive worsening of cord blood pH (7.27 +/- 0.06, 7.21 +/- 0.08, and 7.06 +/- 0.14; P <.05), a progressive increase in PCO (2) (53.39 +/- 8.34 mm Hg, 58.51 +/- 10.55 mm Hg, and 78.31 +/- 20.35 mm Hg; P <.05), and a progressive decline in base excess (-3.18 +/- 2.02 mEq/L, -5. 11 +/- 3.11 mEq/L, and -9.07 +/- 4.59 mEq/L; P <.05). CONCLUSION: This simple classification system for interpreting fetal heart rate tracings accurately predicts normal outcomes for fetuses as well discriminating fetuses in true distress. Further, it identifies an intermediate group of fetuses with a condition labeled fetal stress who might benefit from additional evaluation and possibly from expeditious delivery.

Speech rehabilitation using a voice prostheses following laryngectomy.

The most serious consequence for patients following laryngectomy is the restriction of verbal communication. Since the introduction of laryngectomy significant concerns have already been focused on the field of speech rehabilitation. The operational procedures for the speech rehabilitation include training of the oesophageal voice speech and the voice prostheses. Speech prostheses are available in our hospital since 1983. The speech quality of the speech prostheses is compared with the classical oesophageal voice or to the voice by means of a Provox speech help. Bacteriological and mycological colonisation as a function of the length of implantation are defined. Our approach to the voice rehabilitation after a laryngectomy by use of a spacer during the laryngectomy has proven successful. As a result patients do not fall into a "hole" of non verbal communication. The aim of our efforts is always to create a functioning oesophageal voice after leaving the care of the hospital.

Intrapartum fetal heart rate monitoring.

Intrapartum fetal heart rate monitoring is commonly used to evaluate fetal status in labor, despite a lack of convincing randomized studies to support its use. The National Institutes of Health have helped standardize fetal heart rate monitoring terminology with their 1997 task force report, which will aid clinicians and scientists in their goal of providing quality care and research. The American College of Obstetricians and Gynecologists has recommended the term nonreassuring fetal status for electronic fetal monitor patterns that are not normal; however, Vanderbilt continues to use the terms fetal stress and fetal distress, using specific criteria for each. The approximately 30% of fetal heart rate tracings labeled as fetal stress (or nonreassuring fetal status) can be evaluated further by the use of fetal pulse oximetry, a new technology currently under evaluation in this country.

The Tulipan-Bruner trocar for uterine entry during fetal surgery.

OBJECTIVE: Our goal was to compare the use of a specially designed trocar for initial uterine entry with standard entry by electrocautery in creation of a hysterotomy for fetal surgery. STUDY DESIGN: Ten consecutive patients undergoing hysterotomy for intrauterine repair of myelomeningocele were randomized to initial uterine entry with electrocautery or with the Tulipan-Bruner trocar. Timing of initial uterine entry with electrocautery began with incision into the uterine serosa and ended with incision of the chorioamnionic membranes. Timing of initial uterine entry with the Tulipan-Bruner trocar began with placement of stay sutures and ended with removal of the central introducer from the peel-away sheath. Blood loss was estimated by the primary surgeon. All of the participating surgeons judged the convenience and ease of each technique. The times required for initial uterine entry were compared with an unpaired t test. Statistical significance was set at P <.05. RESULTS: The time required for initial uterine entry with electrocautery was 231 +/- 63 (mean +/- SD) seconds compared with 146 +/- 51 seconds with the trocar (P <.05). The total blood loss for all 10 cases was <50 mL, but the presence of blood in the wound was judged much more inconvenient when electrocautery was used. Finally, electrocautery required 2 surgical assistants in every case, whereas the trocar was readily placed with only a single assistant. CONCLUSION: The Tulipan-Bruner trocar provides quicker, less traumatic uterine entry during creation of a hysterotomy, as compared with electrocautery.

Fetal surgery for myelomeningocele and the incidence of shunt-dependent hydrocephalus.

CONTEXT: Intrauterine closure of exposed spinal cord tissue prevents secondary neurologic injury in animals with a surgically created spinal defect; however, whether in utero repair of myelomeningocele improves neurologic outcome in infants with spina bifida is not known. OBJECTIVE: To determine whether intrauterine repair of myelomeningocele improves patient outcomes compared with standard care. DESIGN: Single-institution, nonrandomized observational study conducted between January 1990 and February 1999. SETTING: Tertiary care medical center. PARTICIPANTS: A sample of 29 study patients with isolated fetal myelomeningocele referred for intrauterine repair that was performed between 24 and 30 gestational weeks and 23 controls matched to cases for diagnosis, level of lesion, practice parameters, and calendar time. All infants were followed up for a minimum of 6 months after delivery. MAIN OUTCOME MEASURES: Requirement for ventriculoperitoneal shunt placement, obstetrical complications, gestational age at delivery, and birth weight for study vs control subjects. RESULTS: The requirement for ventriculoperitoneal shunt placement for decompression of hydrocephalus was significantly decreased among study infants (59% vs 91%; P = .01). The median age at shunt placement was also older among study infants (50 vs 5 days; P = .006). This may be explained by the reduced incidence of hindbrain herniation among study infants (38% vs 95%; P<.001). Following hysterotomy, study patients had an increased risk of oligohydramnios (48% vs 4%; P = .001) and admission to the hospital for preterm uterine contractions (50% vs 9%; P = .002). The estimated gestational age at delivery was earlier for study patients (33.2 vs 37.0 weeks; P<.001), and the birth weight of study neonates was less (2171 vs 3075 g; P<.001). CONCLUSIONS: Our study suggests that intrauterine repair of myelomeningocele decreases the incidence of hindbrain herniation and shunt-dependent hydrocephalus in infants with spina bifida, but increases the incidence of premature delivery.

The clinical significance of intermittent sinusoidal fetal heart rate.

Sinusoidal fetal heart rate may have a spectrum of occurrence that indicates degree of fetal morbidity. Twelve cases of intermittent sinusoidal fetal heart rate were reviewed for fetal outcome. Findings of anemia, low umbilical cord pH, and large base excess support that intermittent sinusoidal fetal heart rate may be an early indicator of impending fetal compromise.

Prevention of preterm birth. Role of daily telephone contact.

OBJECTIVE: To compare the effectiveness of routine management of patients at high risk for preterm delivery to the effectiveness of routine management in combination with daily telephone nursing contact. STUDY DESIGN: The control group, 1 (n = 21), had education and frequent prenatal visits and cervical examinations. The study group, 2 (n = 21), had education, frequent prenatal visits and cervical examination, and daily telephone contact. Group 3 (n = 22) received education but refused to participate. RESULTS: There were no significant differences (SD) between groups in race, smoking, age, multiple gestation, visits, diagnosis of premature labor, mean days gained after diagnosis of premature labor, tocolytic use or bed rest. There was also no SD in preterm birth rate, mode of delivery, number of maternal or neonatal hospital days, mean neonatal weight or gestational age at delivery between groups. While not reducing the overall incidence of preterm birth, this management for all groups resulted in a more advanced gestational age at the time of delivery (mean change = 7.5 weeks, P < .0001) when compared to the patient's first preterm birth. CONCLUSION: This study indicated that daily contact, while providing reassurance and support, did not change the outcome when the study group was compared to women managed similarly but without daily contact.

Placenta previa increta diagnosed at 18 weeks' gestation. Report of a case with sonographic and pathologic correlation.

BACKGROUND: Placenta previa incerta, although uncommon, assumes considerable clinical significance because of the morbidity associated with severe hemorrhage, uterine perforation and infection. The majority of cases are unanticipated and initially identified intraoperatively. CASE: Placenta accreta was diagnosed sonographically at 18 weeks' gestation in a multipara who had previously undergone cesarean delivery. Additionally, the gestation was complicated by chronic renal failure secondary to systemic lupus erythematosus. After appropriate counseling, total abdominal hysterectomy was performed prior to fetal viability. CONCLUSION: Early sonographic evaluation of the placenta is recommended for those at significant risk of invasive placentation. Timely detection facilitates proper preparation and should reduce maternal morbidity.

Emergency management of fetal stress and distress in the obstetric patient.

The clinical use of intrapartum fetal heart rate monitoring remains controversial. Because of its widespread use in this country, interpretation skills must be maintained. Clear and concise criteria for the diagnosis of fetal stress and distress are presented in this article, and the management of fetal distress is discussed.

The umbilical artery Doppler ultrasonographic gradient: confirmation, cause, and comparison of continuous-wave and duplex ultrasonographic pulsed-wave measurements.

The umbilical artery Doppler ultrasonographic gradient has been described, and the need for site-specific nomograms has been pointed out. However, controversy still exists about the cause of this phenomenon and the optimal site for obtaining umbilical artery Doppler ultrasonographic measurements. Cross-sectional measurements of umbilical artery flow velocity waveform (FVW) systolic/diastolic (S/D) ratios were therefore made in 35 gravid women during the second or third trimester of pregnancy with both duplex pulsed-wave (PW) and free-standing continuous-wave (CW) Doppler ultrasonographic equipment. Multiple duplex PW Doppler ultrasonographic signals were recorded at the abdominal cord insertion, placental cord insertion, and free cord sites. Multiple CW Doppler FVWs were obtained from four quadrants, in decreasing order of ease of measurement. Repeated-measures analysis of variance demonstrated a statistically significant decrease in mean and median values of the umbilical artery S/D ratio from the abdominal cord insertion site to the placental cord insertion site. The reduction in the value of the S/D ratio as the placental cord insertion site is approached results more from a decrease in the peak systolic maximum velocity envelope than from an increase in diastolic velocities. Moreover, mean and median CW Doppler ultrasonographic values correlate most closely with corresponding PW measurements of the free cord segment. These data confirm the presence of the umbilical artery Doppler ultrasonographic gradient. Decreasing values of the S/D ratio from the fetal abdomen to the placenta are a result of attenuation of the systolic maximum velocity envelope.(ABSTRACT TRUNCATED AT 250 WORDS)

Phenytoin protects against hypoxia-induced death of cultured hippocampal neurons.

The neuroprotective actions of the anticonvulsant phenytoin (diphenylhydantoin, PHT) were evaluated using 3 week old primary hippocampal cultures derived from 19 day embryonic rat. When added to the culture medium prior to a hypoxic insult, PHT increased neuronal viability two-fold. Doubling extracellular Mg2+ concentration was similarly neuroprotective. In contrast, PHT was unable to protect against hypoxia-induced death in one week old cultures, nor was PHT protective against N-methyl-D-aspartate (NMDA)-induced neurotoxicity in cultures of either age. These findings suggest that non-NMDA receptor mechanisms are important in hypoxia-induced neuronal death, and may have important implications for the treatment of stroke.

Clinical experience with the Hewlett-Packard M-1350A fetal monitor: correlation of Doppler-detected fetal body movements with fetal heart rate parameters and perinatal outcome.

OBJECTIVE: Our purpose was to correlate measures of Doppler-detected fetal movements with standard fetal heart rate parameters and perinatal outcomes. STUDY DESIGN: This prospective, multiinstitutional trial used the Hewlett-Packard M1350A monitor to record simultaneous fetal heart rate baseline, variability, accelerations, decelerations, and number of fetal movements, and duration and percent of total time. These data were compared at 10- and 30-minute intervals during nonstress tests and were correlated with fetal heart rate baseline parameters and maternally perceived fetal movements and with outcomes of infants delivered within 7 days of the last test. RESULTS: At six centers 1704 actocardiograms from 884 third-trimester patients were analyzed. Doppler-detected fetal movement counts, durations, and percent of total time correlated weakly with all baseline fetal heart rate parameters (all values < 0.20). All fetal movement parameters increased significantly in successive 10-minute blocks and in periods of increased or normal fetal heart rate variability compared with those with fetal heart rate variability. The sensitivity, specificity, and predictive values of the percent of total movement time were comparable to those of standard nonstress test parameters. The risk of poor perinatal outcomes after nonreactive nonstress tests was lower in cases with fetal movements than in those without. CONCLUSIONS: Doppler actocardiography may help to discriminate fetal states during antepartum testing. It may prevent inappropriate diagnosis of fetal compromise when the nonstress test is nonreactive or nonreassuring.