Elevated Electron Temperature Coincident with Observed Fusion Reactions in a Sheared-Flow-Stabilized Z Pinch.

The sheared-flow-stabilized Z pinch concept has been studied extensively and is able to produce fusion-relevant plasma parameters along with neutron production over several microseconds. We present here elevated electron temperature results spatially and temporally coincident with the plasma neutron source. An optical Thomson scattering apparatus designed for the FuZE device measures temperatures in the range of 1-3 keV on the axis of the device, 20 cm downstream of the nose cone. The 17-fiber system measures the radial profiles of the electron temperature. Scanning the laser time with respect to the neutron pulse time over a series of discharges allows the reconstruction of the T_{e} temporal response, confirming that the electron temperature peaks simultaneously with the neutron output, as well as the pinch current and inductive voltage generated within the plasma. Comparison to spectroscopic ion temperature measurements suggests a plasma in thermal equilibrium. The elevated T_{e} confirms the presence of a plasma assembled on axis, and indicates limited radiative losses, demonstrating a basis for scaling this device toward net gain fusion conditions.

Implementation of extreme ultraviolet spectroscopy on a sheared-flow-stabilized Z pinch.

A diagnostic for extreme ultraviolet spectroscopy was fielded on the sheared-flow-stabilized (SFS) fusion Z-pinch experiment (FuZE-Q) for the first time. The spectrometer collected time-gated plasma emission spectra in the 5-40 nm wavelength (30-250 eV) range for impurity identification, radiative power studies, and for plasma temperature and density measurements. The unique implementation of the diagnostic included fast (10 ns risetime) pulsed high voltage electronics and a multi-stage differential pumping system that allowed the vacuum-coupled spectrometer to collect three independently timed spectra per FuZE-Q shot while also protecting sensitive internal components. Analysis of line emission identifies oxygen (N-, C-, B-, Be-, Li-, and He-like O), peaking in intensity shortly after maximum current (>500 kA). This work provides a foundation for future high energy spectroscopy experiments on SFS Z-pinch devices.

Sustained Neutron Production from a Sheared-Flow Stabilized Z Pinch.

The sheared-flow stabilized Z pinch has demonstrated long-lived plasmas with fusion-relevant parameters. We present the first experimental results demonstrating sustained, quasi-steady-state neutron production from the fusion Z-pinch experiment, operated with a mixture of 20% deuterium/80% hydrogen by pressure. Neutron emissions lasting approximately 5 µs are reproducibly observed with pinch currents of approximately 200 kA during an approximately 16 µs period of plasma quiescence. The average neutron yield is estimated to be (1.25±0.45)×10^{5} neutrons/pulse and scales with the square of the deuterium concentration. Coincident with the neutron signal, plasma temperatures of 1-2 keV and densities of approximately 10^{17} cm^{-3} with 0.3 cm pinch radii are measured with fully integrated diagnostics.

C-III flow measurements with a coherence imaging spectrometer.

This work describes a coherence imaging spectrometer capable of making spatially resolved CIII flow measurements in the DIII-D lower divertor. The spectrometer exploits a periscope view of the plasma to produce line-of-sight averaged velocity measurements of CIII. From these chord averaged flow measurements, a 2D poloidal cross section of the CIII flow is tomographically reconstructed. Details of the diagnostic setup, acquired data, and data analysis will be presented, along with prospects for future applications.

Note: Electrostatic beams from a 5 T Penning-Malmberg trap.

A procedure is described to extract beams from specially tailored electron plasmas in a Penning-Malmberg trap in a 4.8 T field. Transport to 1 mT is followed by extraction from the magnetic field and electrostatic focusing. Potential applications to positron beams are discussed.

Effect of pediatric surgical practice on the treatment of children with appendicitis.

OBJECTIVE: Acute appendicitis in children is managed by both general surgeons (GSs) and pediatric surgeons (PSs). Our objective was to investigate the economics of surgical care provided by either GSs or PSs for appendicitis. METHODS: The outcome of children within our state who underwent operative treatment for appendicitis (January 1994 to June 1997) by board-certified GSs were compared with the results of PSs. Data were sorted according to patient age and diagnosis according to the International Classification of Diseases, Ninth Revision. Analysis of variance was performed on continuous data, and chi(2) analysis was performed on nominal data; data are depicted as mean +/- standard error of the mean. RESULTS: GSs (n = 2178) managed older children when compared with PSs (n = 1018; 11.0 +/- 0.1 vs 9.1 +/- 0.1 years) and less frequently treated perforated appendicitis (18.8% vs 31.9%). Independent of diagnosis (simple or perforated appendicitis), younger children (0-4 years, 5-8 years, and 9-12 years) who were treated by PSs had a significantly shorter hospital stay and/or decreased hospital charge when compared with those who were treated by GSs. However, older children (13-15 years) seemed to have comparable outcomes. CONCLUSIONS: Younger children with appendicitis have reduced hospital days and charges when they are treated by PSs.

Operative management of chronic pancreatitis in children.

HYPOTHESIS: Chronic pancreatitis in childhood is a rare but potentially debilitating disorder, and failure of conservative therapy with chronic pain medication use is common. We hypothesize that aggressive surgical therapy may hold promise for long-term remission. DESIGN: Retrospective analysis of data collected prospectively for 12 years. SETTING: Tertiary care children's hospital. PATIENTS: Eighteen children (aged 3-13 years, 11 girls) underwent surgical treatment of chronic pancreatitis after 1 to 6 years of various medical therapies (parenteral nutrition, somatostatin, or pain medication). These patients required a mean +/- SD 6 +/- 0 hospitalizations before operation. Pancreatitis was familial in 9 patients, idiopathic in 5, and secondary to trauma and medication use in 2 each. Preoperative endoscopic retrograde cholangiopancreatography showed pancreatic duct dilatation in 7, strictures in 5, ductal stones in 4, and normal findings in 2. The operative therapy consisted of longitudinal pancreaticojejunostomy in 2 children (both children failed pancreaticojejunostomy but improved after undergoing pancreatectomy) and distal pancreatectomy with Roux-en-Y pancreaticojejunostomy in 16 children. OUTCOME MEASURES: Survival, need for rehospitalization or reoperation, and chronic pain medication requirements. RESULTS: All patients survived. Follow-up ranged from 1 to 15 years. Thirteen (72%) of 18 patients have required no further hospitalizations or medications. Two patients required a second operation to convert their longitudinal pancreaticojejunostomy to distal pancreatectomy, and 3 patients have required 2 to 5 additional hospitalizations for recurrent pancreatitis. Endoscopic retrograde cholangiopancreatography on 5 patients 2 to 4 years postoperatively showed patent distal pancreaticojejunostomy. CONCLUSIONS: This series suggests that distal pancreatectomy and pancreaticojejunostomy are effective treatments for this difficult group of patients, while longitudinal pancreaticojejunostomy was ineffective. Long-term relief of pain and reduced need for rehospitalization are the usual results after this procedure.

Glasgow Coma Scale predicts coagulopathy in pediatric trauma patients.

The aim of this study was to determine if neurologic findings at the time of initial resuscitation can predict coagulation abnormalities resulting from head injury. Fifty-three children with head injury were reviewed for Glasgow Coma Scale (GCS), prothrombin time (PT), international normalized ratio (INR), partial thromboplastin time (PTT), use of fresh frozen plasma (FFP) and outcome. Twenty-six of the 53 children (49%) presented with a GCS of 15 and 27 (51%) had a GCS less than 14. The incidence of computed tomography (CT)-documented intracranial injury was 12% in those children with a GCS of 15 versus 78% when GCS < or = 14 (P < .05). Abnormal coagulation (PT > 14.5, INR > 1.2, PTT > 38) in children with a GCS = 15 was 7% v 67% when GCS was < or = 14 (P < .05). A mean of 1 unit of FFP per patient was required in children with a GCS of < or = 14. No child with GCS of 15 and CT evidence for intracranial injury had a coagulopathy, and no child with GCS of 15 required FFP. In head injured children, significant coagulation abnormalities requiring treatment are excluded by the presence of a normal GCS at presentation. Children with GCS less than 14 are at risk for intracranial injury and coagulopathy, this risk increases inversely with the GCS. Children who present with a GCS less than 8 should have FFP prepared at the time of admission. These data may guide the use of laboratory tests and blood bank resources during trauma resuscitation.

Characteristics of pediatric cervical spine injuries.

PURPOSE: The objective of this study was to assess the mechanisms and patterns of injury and outcome in children with cervical (C) spine trauma. METHODS: We reviewed the National Pediatric Trauma Registry between April 1994 and March 1999 and identified (by ICD-9 criteria) all cases of blunt trauma victims with cervical fractures, dislocations, and spinal cord injuries without radiographic abnormality (SCIWORA). Data are shown as mean +/- SEM. RESULTS: During the 5-year period, the incidence of blunt C-spine injury was 1.6% (n = 408 of 24,740 total entries). Mean age was 10.5+/-0.3 (1 to 20) years, and 59% were boys. Leading mechanisms were motor vehicle accidents (n = 179; 44%), sports (n = 66; 16%), and pedestrian injuries (n = 57, 14%). Younger (< or =10 years) children more often sustained high (C1 to C4) vs low (C5 to C7) injuries (85% v 57%; P<.01) and also had a higher incidence of dislocations (31% v 20%; P<.01) and cord injuries (26% v 14%; P<.01), whereas older children had more C-spine fractures (66% v 43%; P<0.01). Mortality rates (overall, 17%) were higher in younger children (n = 180) when compared with older children (n = 228; 30% v 7%; P<.01). Overall, the majority of deaths (93%) were associated with brain injuries. No children with cervical dislocations had neurologic sequelae. The preponderance of children with fractures (83%) also were without neurologic injury, whereas those associated with SCIWORA usually were (80%) partial. Overall, complete cord lesions were infrequent (4%). CONCLUSIONS: These data, representing the largest series to date, confirm that blunt C-spine injuries in children are rare. Patterns of injury vary significantly according to child age. Major neurologic sequelae in survivors is uncommon, does not correlate well with cord level, and rarely is complete.

Outcome of the antegrade colonic enema procedure in children with chronic constipation.

BACKGROUND: Chronic constipation and fecal incontinence in children related to pelvic trauma, congenital anomalies, or malignancy will eventually lead to significant social and psychologic stress. Maximal medical treatment (daily enemas and laxatives) can also be difficult to maintain in many children. METHODS: At our children's hospital, 11 children with chronic constipation or fecal incontinence or both underwent the antegrade colonic enema (ACE) procedure. The operation involved constructing a conduit into the cecum using either the appendix (n = 8) or a "pseudo-appendix" created from a cecal flap (n = 3). We report our surgical results. RESULTS: Mean child age was 9.6 (5 to 18) years. With a mean follow-up of 14 (6 to 24) months, 10 of the children (91%) had significant improvement and 7 children (64%) are completely clean with no soiling and controlled bowel movements after irrigation. CONCLUSIONS: Regular colonic lavage after the ACE procedure allows children with chronic constipation and fecal incontinence to regain normal bowel habits and a markedly improved lifestyle. This procedure should be considered before colostomy in children and adults for the treatment of fecal incontinence from a variety of causes.

Acute ovarian torsion in children.

BACKGROUND: Acute ovarian torsion (OT) is an uncommon cause of abdominal pain in children and is frequently confused with other conditions. METHODS: We reviewed the records (1983 to 1999) of all children treated for acute OT at our children's hospital. RESULTS: Mean child age (n = 51) was 12.5 +/- 0.3 years. Children presented with either right-sided (n = 29) or left-sided (n = 22) pain. Diagnosis of OT was confirmed preoperatively by ultrasound (73%) or computed tomography (CT) scan (10%) while nine children (17%) with right-sided pain underwent surgery for presumed appendicitis. Despite a relatively short time from diagnosis to surgery, all 51 children required salpingooophorectomy. Contralateral biopsy was performed in 29% and 57% had an appendectomy. Younger children more commonly had either a mature cystic teratoma or torsion with no underlying abnormality as an etiology compared with OT in older children that was more likely to result from either a follicular or corpus luteal cyst. Pathologic examination of the contralateral ovary and appendix was normal in all children who underwent biopsy and appendectomy. CONCLUSION: Ultrasonography with color doppler is helpful for differentiating acute OT from appendicitis. Although the twisted ovary can rarely be salvaged, the etiology is usually benign. Preoperative serum markers and contralateral ovary biopsy may be unnecessary.

Prostatorectal fistula associated with tubular colorectal duplication.

Tubular colonic duplications are exceedingly rare. The authors present an unusual case of a boy with a persistent prostatorectal fistula resulting from a tubular colorectal duplication. The current case is unique for 2 reasons: (1) the presence of a fistula without any concomitant genitourinary anomalies and (2) the existence of a prostatorectal fistula.

The incidence of spermatic cord structures in inguinal hernia sacs from male children.

Inguinal herniorrhaphy is a common surgical procedure in children. Controversy exists regarding the usefulness of microscopic examination of hernia sacs, and changes in reimbursement schemes have heightened this controversy. We summarize our experience with histologic examination of these specimens to establish benchmarks for the number of spermatic cord structures in inguinal hernia sacs from male children. A 14 1/2 consecutive calendar year review of pathology reports and histologic sections of hernia sacs was conducted at a tertiary care children's hospital. Of 7,314 males (range newborn to 19 years old), 65% had bilateral and 29% had unilateral herniorrhaphy (6% unknown). Seventeen cases contained vas deferens (0.23%); 22 had epididymis (0.30%); and 30 had embryonal rests (0.41%). Either vas deferens or epididymis was found in 0.53% of patients. No cases contained bilateral vas deferens, bilateral epididymis, or vas deferens in one side with epididymis in the contralateral side. Three hernia sacs contained co-existing vas deferens and epididymis. Our study helps to provide surgeons with information for preoperative counseling regarding potential injury to the vas deferens or epididymis. This study provides baseline comparison data for quality improvement programs. We believe that each institution should weigh the costs, risks, and benefits of performing microscopic examinations on hernia sacs, depending on their own experience and data.

Rollover injuries in residential driveways: age-related patterns of injury.

BACKGROUND: The major objective of the present study was to determine the severity of nonfatal injuries sustained by children (<16 years old) when a motor vehicle rolls over them. We also sought to determine whether younger children (<24 months old) demonstrated different patterns of injury and/or a worse outcome, compared with older children (>24 months old). METHODS: We reviewed the medical records of 3971 consecutive admissions to a single trauma service at an urban children's hospital between March 1990 and October 1994. During this time period, 26 (0.7%) children presented with rollover injuries incurred by motor vehicles in residential driveways. Outcome was measured by length of both intensive care unit admission and hospitalization. RESULTS: Two children died shortly after admission and were excluded from the remainder of the study. Younger children (<24 months old) had significantly higher injury severity scores and lower pediatric trauma scale scores. Both the duration in the intensive care unit and the length of hospitalization were significantly longer in younger children, compared with children >24 months old. One explanation for these observations was that younger children had a significantly higher incidence of both head and neck and extremity injury but a similar incidence and severity of chest and abdominal trauma, compared with older children. Injuries requiring operative intervention were rare. CONCLUSION: Younger patients sustaining rollover injuries in the residential driveway have a worse outcome, in part, because of the head and neck or extremity injures that they incur. The majority of rollover injuries can be managed conservatively. pediatric trauma, driveway, pedestrian events, rollover injuries, injury severity score, pediatric trauma scale.

Toupét fundoplication for gastroesophageal reflux in childhood.

HYPOTHESIS: Gastroesophageal reflux (GER) is a common condition in childhood that frequently requires operative treatment. The 360 degrees Nissen fundoplication (NF) has been the standard operation for GER, but is associated with substantial rates of recurrence, "gas bloat," gagging, and dysphagia. I believe that the Toupet fundoplication (TF), a 270 degrees posterior wrap originally described in conjunction with myotomy for achalasia, has fewer complications, and its longterm outcome in children compared with NF is favorable. DESIGN: Nonrandomized controlled trial. SETTING: Tertiary care children's hospital. PATIENTS: Two hundred fifty-six children (aged 3 months to 16 years) with GER disease unresponsive to nonoperative therapy who underwent either NF (n = 102) or TF (n = 154). INTERVENTION: Operative repair of GER disease by either NF or TF. MAIN OUTCOME MEASURES: Time to first feeding, time to discharge from the hospital, postoperative dysphagia complications, recurrence, and rehospitalization and reoperation rates for each fundoplication technique. RESULTS: The 2 fundoplication techniques had equivalent recurrence rates, but TF had significantly lower rates of postoperative dysphagia (P = .008) and rehospitalization/reoperation rates (P = .005) and significantly shorter times to discharge from the hospital (P = .01) and to the first feeding (P = .02). CONCLUSIONS: These data show that both NF and TF are effective procedures for GER in children, with acceptable recovery times and low recurrence rates. However, TF results in earlier feeding and discharge from the hospital and has a significantly lower incidence of dysphagia, gagging, and gas bloat, resulting in fewer rehospitalizations. In this population, TF seems to be superior to NF.

The impact of intraoperative culture on treatment and outcome in children with perforated appendicitis.

BACKGROUND: Most protocols for the operative treatment of perforated appendicitis use a routine culture. Although isolated studies suggest that routine culture may not be necessary, these recommendations generally are not based on objective outcome data. METHODS: The authors reviewed the records of 308 children who underwent operative treatment for perforated appendicitis between 1988 and 1998 to determine if information gained from routine culture changes the management or improves outcome. Inclusion criteria included either gross or microscopic evidence of appendiceal perforation. RESULTS: Mean patient age was 7.5 years, 51% were boys, and there was no mortality. The majority of children (96%) underwent culture that was positive for either aerobes (21%), anaerobes (19%), or both (57%). Antibiotics were changed in only 16% of the patients in response to culture results. The use of empiric antibiotics, as compared with modified antibiotics, was associated with a lower incidence of infectious complication, shorter fever duration, and decreased length of hospitalization. We also investigated the relationship between culture isolates and antibiotic regimens with regard to outcome. The utilization of antibiotics suitable for the respective culture isolate or organism sensitivity was associated with an increased incidence of infectious complication and longer duration of both fever and length of hospitalization. Finally, the initial culture correlated poorly with subsequent intraabdominal culture (positive predictive value, 11%). CONCLUSION: These outcome data strongly suggest that the practice of obtaining routine cultures can be abandoned, and empiric broad spectrum antibiotic coverage directed at likely organisms is completely adequate for treatment of perforated appendicitis in children.

Reoperation for Hirschsprung's disease.

BACKGROUND/PURPOSE: Reoperation for Hirschsprung's disease traditionally has been used for patients with anastomotic leaks or stricture or with severe constipation from retained aganglionic segment or neuronal dysplasia, but there is little information regarding its use for other complications and the long-term outcome in these patients. METHODS: In a 23-year period, 107 infants and children underwent Soave (68 patients) or Duhamel (39 patients) pull-through procedures. The age at operation was newborn to 6 years (mean, 10 months). Eighty percent had aganglionosis limited to the rectosigmoid colon. Follow-up was by office visit or telephone (mean, 8.5 years). RESULTS: Twenty-three of the 68 patients with Soave pull-through (34%) underwent reoperation for intractable enterocolitis (10 patients, all 10 cured); anastomotic stenosis (four patients, three cured, one continued diversion); anastomotic leak (four patients, four cured); retained aganglionic segment (three patients, three cured); one necrosis of pull-through converted to Duhamel and cured; and one rectal prolapse that was diverted. Fifteen of the 39 patients with Duhamel procedure (38%) underwent reoperation for severe constipation (seven patients, six cured, one diverted); persistent rectal septum (four patients, 4 cured); and intractable enterocolitis (four patients, three cured, one diverted). Overall, 21 of 23 patients (91%) with reoperation after Soave procedures were cured, whereas 13 of 15 patients (87%) who underwent reoperation after Duhamel procedure were cured, and four patients remain diverted. CONCLUSIONS: These data show that aggressive reoperation can result in a high cure rate in Hirschsprung's disease. Although there is no significant difference in the rate of reoperation after Duhamel and Soave procedures, the patients with Soave pull-through required more complex reoperations, with several requiring more than one procedure. An aggressive approach to reoperation in patients with Hirschsprung's disease clearly is justified.

A state-wide evaluation of appendectomy in children.

BACKGROUND: Traditional management of appendicitis in children involves open appendectomy (OA), an operation that is relatively inexpensive and carries few risks and complications. However, little information is available regarding the use, cost, and complication of laparoscopic appendectomy (LA) in children. METHODS: Our initial aim was to determine if LA is frequently performed in children (<15 years). We then compared the surgical results of OA versus LA. In conjunction with the Missouri Department of Health, we evaluated 793 children treated for appendicitis throughout the state between January 1997 and June 1997. The authors were blinded to the patient, surgeon, and hospital; no children were excluded. RESULTS: LA was infrequently performed in children with advanced disease. Overall, children undergoing LA were older and had a shorter hospitalization but no difference in hospital charge. When separated by child age, LA was associated with a shorter length of stay in all groups (0 to 5, 6 to 10, and 11 to 15 years) but only children in the 6 to 10 year range had a lower hospital charge when compared with patients undergoing OA. CONCLUSIONS: LA is becoming a common surgical approach for older children with simple appendicitis. Furthermore, these data suggest that LA, independent of individual surgeon or medical center, is associated with a decreased length of hospitalization without a significant difference in hospital charge.