Blast injuries--and the pivotal role of trauma surgeons.

An explosion is the sudden release of energy and its radial propagation through air, solid structures and living tissue. Treatment of blast injuries is complex and combines the principles of penetrating and blunt trauma, chemical or thermal burns and disaster and mass casualty management. Primary blast injuries are a direct result of the explosion itself. The sudden release of energy is translated into a shock wave that travels at supersonic speed (5000 metres/second). There is a sudden and short-lived rise in pressure, followed by a prolonged negative pressure, or vacuum, responsible for additional injury. The organs most at risk for primary blast injuries are the lungs, the ears and the gastrointestinal tract. The explosion also sets solid objects in motion; these act as projectiles, and can travel over far greater distances (secondary blast injuries), and their management is no different from penetrating or blunt trauma from other causes. The explosion may cause not only "projectiles," but the body itself to be displaced: These tertiary blast injuries include traumatic amputations and crush injuries following land mine explosions. Finally, quaternary blast injuries comprise other forms of associated trauma, such as burns, asphyxia or poisoning from release of noxious substances by the blast. These injuries can be particularly taxing for rescue teams because of their tendency to affect large amounts of patients and the risk they pose to the rescuers themselves. Individual management of the blast injury victim requires a multidisciplinary team; terrorist or wartime bombings also require expertise in disaster management and triage.

Placental weight, birth weight and fetal:placental weight ratio in dichorionic and monochorionic twin gestations in function of gestational age, cord insertion type and placental partition.

INTRODUCTION: We established reference values for placental weight, birth weight, and fetal:placental weight ratio (FPR) (a possible index of placental functional efficiency) in monochorionic and dichorionic twin gestations. METHODS: Placental weight, birth weight, and FPR in function of gestational age, cord insertion type and placental sharing were determined in 151 dye-injected diamniotic-monochorionic and 198 double-disc diamniotic-dichorionic twin placentas (25-39 weeks' gestation). RESULTS: As expected, FPR values increased with gestational age in both groups. Birth weights and placental weights of monochorionic twins >28 weeks' gestation were significantly lower than those of age-matched dichorionic twins. When stratified per placental weight, the birth weights and FPR values of monochorionic twins were overall lower than those of dichorionic twins within the same placental weight category. However, in the subset of monochorionic twins with small share in unevenly partitioned placentas, birth weights and FPR values per placental weight were similar to those of dichorionic twins, and significantly higher than those of monochorionic twins with larger share or even placental sharing. Cord insertion type did not correlate with birth weight or FPR values per placental weight in either twin type. DISCUSSION: Reference values were generated for placental weight, birth weight and FPR in monochorionic and double-disc dichorionic twins. The generally lower FPR per placental weight in monochorionic twins compared with dichorionic twins is suggestive of inherently lower placental functional efficiency in monochorionic gestations. The mechanisms and clinical implications of the apparent differential modulation of FPR/efficiency in monochorionic twins according to placental partitioning remain to be determined.

Surgical and metabolic aspects of liver transplantation for tyrosinemia.

Tyrosinemia is the diagnosis of a very small percentage of patients undergoing liver transplantation worldwide. Tyrosinemia is endemic within our referral area however, and fully one-third of the liver transplantations at our institution are done for this disease. Since 1986, 15 patients with tyrosinemia (TYR) and 31 patients with various other indications (non-TYR) have undergone a total of 51 liver transplantations. The 36-month actuarial survival for TYR patients is 87%, compared with 74% for non-TYR patients. Liver transplantation for hereditary tyrosinemia and other metabolic disorders without portal hypertension or previous portohepatic operations is notably easier to perform. Intraoperative blood loss was less, length of hospital stay was shorter, and incidence of infections was lower in TYR than in non-TYR patients. Less than 10% of TYR patients had foci of hepatocellular carcinoma at the time of transplantation. For this reason, and while most patients with tyrosinemia will eventually require liver transplantation, our results do not support systematic early transplantation before the age of two years.

Fate of the type II pneumocyte following tracheal occlusion in utero: a time-course study in fetal sheep.

Tracheal occlusion in utero has been shown to cause accelerated fetal lung growth and is now being considered as a therapeutic modality for pulmonary hypoplasia. We report the effects of tracheal ligation on the surfactant-producing type II pneumocyte population. Three groups of fetal lambs underwent tracheal ligation of 2 weeks', 4 weeks' and 6 weeks' duration, respectively, and all were sacrificed at 136 days' gestation (9 days pre-term). Nonoperated twins served as controls. The type II pneumocyte population was studied morphometrically using a combination of anti-surfactant protein B immunohistochemistry and computer-assisted stereologic morphometry at light and electron microscopic levels. Single-factor ANOVA was used for statistical analysis. Two weeks of tracheal ligation resulted in doubling of the total lung volume as a result of airspace distension and, to lesser extent, growth of the tissue compartment. With increasing duration of tracheal ligation, there was no additional lung growth. However, more prolonged tracheal occlusion was found to result in significant reduction of the surfactant system, as reflected in the marked decrease of total pneumocyte type II volume (3.14 cm3, 0.95 cm3, and 0.46 cm3, after 2, 4, and 6 weeks of ligation, compared with 5.96 cm3 for controls) and total pneumocyte type II number (13.9 x 10(9), 3.8 x 10(9), and 2.4 x 10(9), compared with 53.2 x 10(9) for controls). Ultrastructural analysis of the type II cells in obstructed lungs showed vacuolar degenerative changes that, after 6 weeks of ligation, were apparently irreversible. In utero tracheal ligation causes fetal lung hyperplasia, but results in reduction of and injury to the surfactant-producing cell population. Before tracheal occlusion can find wide-spread clinical application, its pathophysiology needs to be further elucidated.

Small-bowel obstruction by an inflatable penile prosthesis reservoir.

Early experience with the inflatable penile prosthesis has been plagued with high failure rates. With improvements in design and surgical technique, the relative incidence of mechanical failures has decreased from 69.9% of all complications to 38.2%, increasing the relative importance of pathologic failures (from 27.3% to 56.4%). The overall complication rate has decreased from an initial 32.5% to 9.0% in recent series. A unique case of small-bowel obstruction caused by intraluminal migration of the reservoir of an inflatable penile prosthesis is described. It was successfully managed by resection of the affected bowel loop and extraperitoneal reimplantation of the reservoir. Although general surgeons are not involved in the placement of these devices, it is important for us to be aware of the possibility of erosion and migration of the component parts, which may result in potentially lethal gastrointestinal and other complications that we may be called on to assess.

Adult foregut duplication.

We report a gastric duplication in a 23-year-old man. The case is unique because the stomach is the rarest location for enteric duplication, the duplication almost never occurs in adults, and the duplication consisted exclusively of pancreatic tissue. This extreme example illustrates the close embryologic and anatomic association between stomach and pancreas. A case is made for the use of the general term of foregut duplication to avoid confusing nomenclature.

Short-term tracheal occlusion corrects pulmonary vascular anomalies in the fetal lamb with diaphragmatic hernia.

BACKGROUND: Sustained fetal tracheal occlusion (TO) results in accelerated lung growth but causes severe type II cell depletion. Temporary TO fails to cause lung growth in a congenital diaphragmatic hernia (CDH) model but preserves type II cells and corrects pulmonary hypertension. Herein, we study the pulmonary vascular changes caused by temporary TO. METHODS: CDH was created in 12 fetal lambs (65-70 d; term, 145 days). In 6 lambs, the trachea was occluded for 2 weeks (CDH + TO; 108-122 d). Animals were killed at 136 days. The lungs were processed with elastin stains and anti-alpha-smooth muscle actin antibody. Partial or circumferential presence of inner and outer elastic lamina was used to determine muscularization of pulmonary arterioles. The percent of medial wall thickness was plotted against vessel diameter for each group. RESULTS: Lung weight/body weight was smaller in lambs with CDH (1. 35% +/- 0.56%) and CDH + TO (1.70% +/- 0.34%) than in control lambs (3.55% +/- 0.56%; P <.05, single-factor analysis of variance). The smallest muscularized vessel was 113 +/- 50 microm, and the largest nonmuscularized vessel was 138 +/- 49 microm in lambs with CDH, significantly different from control lambs (185 +/- 69 microm and 350 +/- 116 microm, respectively) and lambs with CDH + TO (185 +/- 97 microm and 245 +/- 100 microm, respectively; P <.05). In lambs with CDH, only 25% of vessels of less than 60 microm were nonmuscularized, compared with 81% in control lambs (P <.05) and 74% in lambs with CDH + TO.Conclusions. Temporary tracheal occlusion, from 108 to 122 days, corrects the abnormal muscularization of pulmonary arterioles seen in CDH. These morphometric findings parallel physiologic results at birth and further suggest that short-term occlusion, which preserves surfactant-producing type II pneumocytes without lung growth, may be sufficient to improve neonatal outcome of diaphragmatic hernia.

Cost-effectiveness of laparoscopy in children.

BACKGROUND: Laparoscopy may offer fast recovery and improved cosmesis, but its cost has been perceived as excessive. OBJECTIVE: To analyze the total hospital costs of laparoscopy vs open surgery. DESIGN: Retrospective cost-effectiveness analysis evaluating all cases performed in a 36-month period (September 1995 to August 1998). Cases were evaluated for operative time, itemized cost of supplies, and length of hospitalization. SETTING: Operations performed by pediatric surgeons in a tertiary care children's hospital. PATIENTS: Consecutive children undergoing laparoscopic or open appendectomies, cholecystectomies, fundoplications, and splenectomies. Patients were not randomized to laparoscopy, or open surgery. INTERVENTIONS: Laparoscopic procedures performed with a core set of reusable equipment and a limited number of disposable instruments. MAIN OUTCOME MEASURES: Cost surplus of laparoscopy was evaluated, and compared with savings associated with decreased hospital stay, to obtain cost-effectiveness of laparoscopy per procedure. RESULTS: There were 26 laparoscopic and 359 open appendectomies; 33 laparoscopic and 3 open cholecystectomies; 16 laparoscopic and 18 open fundoplications; and 16 laparoscopic and 7 open splenectomies. Excess operating costs per procedure were $442.00 for appendectomy, $634.60 for fundoplication, $847.50 for cholecystectomy, and $1551.30 for splenectomy. Hospital stay was decreased for all laparoscopies, resulting in an overall savings per laparoscopic procedure of $2369.90 for appendectomy, $5390.90 for fundoplication, $1161.00 for cholecystectomy, and $858.90 for splenectomy. CONCLUSIONS: Laparoscopy is cost-effective, particularly for fundoplication, appendectomy, and cholecystectomy. Detailing the costs of supplies, operating time, and length of stay allows interinstitutional comparison and critical cost-analysis of laparoscopy. With a more selective use of reusable instruments and further shortening of operative time, the global savings of laparoscopy may increase.

Natural protective mechanisms against endoscopic white-light injury in the fetal lamb eye.

OBJECTIVE: To evaluate light transmission, possible light trauma, and techniques for protection of the fetal eyes during intrauterine videoendoscopic surgery in a sheep model. METHODS: In vitro studies were done at various gestational ages, including spectrometry of light output by a halogen light source and telescope and light transmission by spectrophotometry in the range of 180-3000 nm through amniotic fluid (AF) and fetal eyelids. In vivo electron-microscopic, morphologic analysis of the retinas of 65-, 95-, 108-, and 112-day-old fetal lambs with (n = 8) and without (n = 8) 30 minutes' light exposure to the open eye was also done. RESULTS: The light spectrum at the tip of the telescope was 400-750 nm, with a maximum irradiance of 3x10(-3) W/cm2 at 580 nm. In the ultraviolet spectrum (less than 300 nm), irradiance was less than 0.5x10(-3) W/cm2. Light transmission through ovine AF ranged from 30% at 300 nm to 89% at 700 nm at 84 days' gestation, decreasing to less than 0.01% (300 nm) and 70% (700 nm) at 112 days. Fetal eyelids did not transmit more than 1% of light (any wavelength). After direct in vivo light exposure, no retinal damage was found. Photoreceptors were present from 108 days onward, but chromophores were scant or absent at all ages studied. CONCLUSION: The light spectrum of a standard endoscope is limited to 400-750 nm; ultraviolet light is filtered out. The AF transmits harmful blue light poorly. Fetal eyelids seem to protect the eye by extremely low transmission and light dispersion. Even with the eye open, no morphologic retinal damage was found. The strong light sources used with fetal endoscopy did not appear to pose a threat to the fetal retina.

Fetoscopy-guided fetal endoscopy in a sheep model.

Video-endoscopic surgical treatment of the fetus may, in the future, become an alternative to open fetal operation. Six 95-day-old fetal lambs were examined through intrauterine endoscopy using amnioinfusion and specially designed balloon-tipped cannulas. The fetuses were monitored endoscopically for oxygen saturation, heart rate and temperature throughout the procedure. With a rigid 5 millimeter telescope and a flexible 3 millimeter endoscope, the respiratory and upper gastrointestinal tracts could be examined. No mucosal or other trauma was noted upon completion of the endoscopy; all lambs survived the procedure. While the applications of fetal endosurgery are likely to be similar to those of open fetal operation, fetal endoscopy (looking in the fetus) is a new entity for which clinical relevance (rather than mere feasibility) remains to be demonstrated. This technique, however, could become a valuable research tool to study fetal gastrointestinal and pulmonary physiologic factors in situ.

Selective use of ultrasonography for acute appendicitis in children.

BACKGROUND: To evaluate the role of ultrasonography in children with equivocal signs of acute appendicitis, and correlate with initial clinical impression and pathological findings. METHODS: This is a prospective evaluation of all children presenting with a possible diagnosis of appendicitis during a 14-month study period. Patients with unequivocal clinical signs of appendicitis underwent appendectomy without ultrasonography. Patients with equivocal signs had documentation of the clinical impression and subsequent abdominal ultrasound. Statistical analysis of results was performed using the chi-square test (P <0.05 significant). RESULTS: Two hundred fifteen consecutive children were enrolled. Signs were unequivocal in 116 and equivocal in 99. Seven patients in the first group had a normal appendix at operation. Of the 99 patients with equivocal signs, there were 28 true positives, 3 false positives, 64 true negatives, and 4 false negatives. In equivocal cases, sensitivity of the initial clinical impression versus ultrasound was 50% and 88%, respectively (P <0.05). Specificity was 85% and 96%, respectively. The positive and negative predictive values improved from 63% to 90% and 78% to 94%, respectively, with the use of ultrasonography. CONCLUSIONS: The low false positive rate (6%) in clinically obvious cases of appendicitis does not, in our opinion, warrant ultrasonography. In clinically equivocal cases, ultrasonography is a fast, sensitive, and specific diagnostic modality to diagnose or rule out appendicitis, avoiding the need for prolonged observation and/or hospitalization.

Open and laparoscopic appendectomy are equally safe and acceptable in children.

BACKGROUND: The aim of this study was to evaluate prospectively whether laparoscopic (LA) and open appendectomy (OA) are equally safe and feasible in the treatment of pediatric appendicitis. METHODS: A total of 517 children with acute appendicitis were randomly assigned to undergo LA or OA appendectomy, based on the schedule of the attending surgeon on call. Patient age, sex, postoperative diagnosis, operating time, level of training of surgical resident, length of postoperative hospitalization, and minor and major postoperative complications were recorded. Chi-square analysis and the Student t-test were used for statistical analysis. RESULTS: In all, 376 OA and 141 LA were performed. The two groups were comparable in terms of patient demographics and the incidence of perforated appendicitis. The operative time was also similar (47.3 +/- 19.7 vs 49.9 +/- 12.9 min). The overall incidence of minor or major complications was 11.2% in the OA group and 9.9% in the LA group. CONCLUSION: Pediatric patients with appendicitis can safely be offered laparoscopic appendectomy without incurring a greater risk for complications. Nevertheless, a higher (but not significantly higher) abscess rate was found in patients with perforated appendicitis who underwent laparoscopy.

Requirements for fetal surgery: the diaphragmatic hernia model.

Fetal surgery for congenital diaphragmatic hernia and other fetal conditions can only be considered if (1) the morbidity of antenatal intervention is acceptable, (2) the diagnosis of the condition can be made accurately, (3) the condition can be differentiated from other, non-surgical anomalies. In addition, (4) the natural evolution of the disease, if left untreated, should be predictable, and the condition should be lethal or severely debilitating, (5) there should not exist adequate postnatal treatment, and (6) the proposed in utero operation should be technically feasible. Open fetal surgery has proven too invasive to be justified for the treatment of diaphragmatic hernia, and progress in postnatal therapy (including ECMO) has dramatically improved the neonatal outcome in all but a severe subgroup of patients. Recently, advances in endoscopic fetal surgery (which appears to be less stressful for the fetus and the gravid uterus) and a new approach to accelerate fetal lung growth and maturation have renewed the feasibility of in utero intervention for diaphragmatic hernia.

Experience with a multidisciplinary antenatal diagnosis and management model in fetal medicine.

BACKGROUND: Fetal medicine is a new and evolving specialty. Complex fetal conditions may require the multidisciplinary input of clinicians from many different specialties. METHODS: Referral of fetal patients was made to a multidisciplinary antenatal diagnosis and management (MADAM) board if more than one specialty (in addition to maternal-fetal medicine) needed to be intimately involved in the evaluation or care of the fetus; consultation would probably lead to alterations in fetal or perinatal management; or development or revision of management guidelines was anticipated. The case log of the MADAM conferences was reviewed retrospectively for number and type of fetal anomalies, and outcome of the presentation to the MADAM board. RESULTS: During a 5-year period, 1% of 25654 pregnant women who were evaluated required consultations with individual pediatric and pediatric surgical specialists. Of these, 114 patients were referred to one of 77 MADAM conferences for consensus recommendation. Of these 77 discussions, 32 (42%) led to an alteration in prenatal management, 14 (18%) led to co-ordination of postnatal management and 12 (16%) led to the establishment of a new treatment guideline, or the modification of an existing one. In all, perinatal management was altered in 75% of cases. CONCLUSION: The MADAM model functions as a forum for exchange of up-to-date scientific information, development of evidence-based treatment protocols and continuity of care through the pre-, peri- and postnatal periods.

Anterior perineal approach and three-flap anoplasty for imperforate anus: optimal reconstruction with minimal destruction.

Despite progress in the treatment of imperforate anus, anal stenosis, rectal prolapse, and other late complications may still arise. In 1987, we described the three-flap anoplasty for the treatment of rectal prolapse following pull-through operations. Since 1986, we have performed 14 three-flap anoplasties in combination with an anterior perineal rectal pull-through for primary treatment of imperforate anus. The mean age at definitive repair was 4.4 months (range, 0 to 14 months). Eleven of the 14 primary pull-through procedures could be performed through a perineal approach only. There were no deaths. At a mean follow-up of 24.2 months, none of the patients has developed prolapse, and only one has had a temporary stenosis. Three children are already fully continent, and soiling is absent in 12. All have a good sphincter tone. Although it is too early to evaluate long-term results, it appears that the three-flap anoplasty prevents mucosal prolapse through the interposition of a skin-lined anal canal. Moreover, a combination of this technique with the anterior perineal approach provides an excellent exposure with minimal dissection of the perineal and pelvic musculature and allows for easy and safe pull-through of the rectal pouch, making an abdominal counterincision unnecessary in most cases. It reproduces at the same time a normal anatomy while taking advantage of all existing structures.

Cholelithiasis in newborns and infants.

Cholelithiasis in infants is rare, and has usually been associated with hemolysis, ileal disease, congenital anomalies of the biliary tree, hyperalimentation, and prolonged fasting. With the increased use of abdominal ultrasonography (US), more cases of cholelithiasis are being discovered. We report our experience with 13 infants diagnosed on abdominal US to have gallstones. There were 9 boys and 4 girls with an average age at diagnosis of 2.6 months (range, 0 to 9 months). Predisposing factors could be identified in only 6 of the 13 patients. Two patients with obstructive jaundice underwent cholecystectomy and common bile duct exploration. One patient with choledocolithiasis and common bile duct dilatation was observed. His stone passed spontaneously, with resolution of symptoms. Ten patients without cholestasis remained asymptomatic, with disappearance of lithiasis in five of them. Neonatal cholelithiasis is more common than previously suspected; it seems to affect males more often than females and is usually not associated with known predisposing factors. It appears to be a temporary, self-limiting phenomenon, and an aggressive approach is not warranted in the asymptomatic infant. Surgical or radiological intervention should be reserved for the symptomatic patients or those with underlying lithogenic disorders.

Neonatal gastrointestinal perforations.

Neonatal gastrointestinal perforation has been associated with mortality rates of 40% to 70%. Over the past 20 years, 81 infants (46 boys and 35 girls) were treated for a gastrointestinal perforation at this institution. Perforation occurred from birth to 50 days (average, 8.2 days). Etiologies included necrotizing enterocolitis (NEC) (68%), meconium ileus (10%), and idiopathic gastric perforation (7%). Seventy-six infants underwent surgical exploration and five infants, considered too small or too sick to withstand a laparotomy, were treated with peritoneal lavage only. There were 29 deaths, an overall mortality of 36%. Ninety percent of the death occurred in patients with NEC, while all patients with gastric perforations survived. There has not been a significant improvement in survival in recent years, partly because of an increase in the proportion of NEC-related perforations. However, there is a narrowing of the mortality gap between low birth weight and normal weight infants. As the risk inherent to laparotomy in neonates is decreasing, other factors, such as the underlying etiology or the site of perforation, play a more important prognostic role.

Surgical indications in antenatally diagnosed ovarian cysts.

The antenatal diagnosis of ovarian cysts poses a therapeutic dilemma because the natural history of these lesions is not well known. A retrospective review from 1980 to 1989 showed 29 ovarian cysts in 27 patients diagnosed by prenatal ultrasonography performed between 28 and 36 weeks of gestation. Nineteen cysts were initially observed. Eleven cysts resolved (diameter less than 2 cm), three are decreasing, three were lost to follow-up, and two underwent resection. Eight patients underwent surgical exploration immediately following birth. The diagnosis of benign ovarian cyst was confirmed histologically in all cases. A review of the literature showed an additional 230 cases of antenatally diagnosed ovarian cysts. Simple cysts of the ovary tend to resolve spontaneously and, therefore, may be treated conservatively. Serial ultrasonography allows accurate diagnosis and long-term assessment of ovarian cysts in the neonate and may prevent unnecessary oophorectomy. Patients with cysts larger than 4 cm may be candidates for percutaneous aspiration, or should undergo removal of the cyst because of a significant risk of torsion. Complex cystic masses, symptomatic ovarian cysts, and cysts that do not resolve should be removed.

Benign liver tumors in children: a 25-year experience.

The most common benign liver tumors are hemangiomas and hamartomas, both of mesenchymal origin. Mortality for patients with these tumors has traditionally been substantial despite benign histology. Between 1965 and 1989, 22 patients were treated for a benign liver tumor. This represents 42% of all primary neoplasms of the liver observed during this period. Incidental findings of liver tumors at autopsy were excluded from this series. There were 9 boys and 13 girls with a mean age at presentation of 2.3 years (range, birth to 14 years). Sixteen had hemangiomas and presented earlier in life (mean age, 4.4 months). In this subgroup, high-output cardiac failure was present in 58% of the newborns. Seven hemangiomas were resected, four were observed, three were treated with digitalis, diuretics, and steroids, and one received epsilon-aminocaproic acid. Nonhemangiomatous tumors included four hamartomas, one focal nodular hyperplasia, and one nodular transformation. All six were resected. There was one death early in the series. At a mean follow-up of 38 months, 21 of the 22 patients are cured or asymptomatic. In the past, mortality rates of close to 90% have prompted many investigators to advocate resection of every symptomatic hemangioma. With the availability of more sophisticated imaging techniques and refinements in the treatment of cardiac failure, surgery can be used more selectively. Hepatic resections, once considered heroic, can now be performed with minimal morbidity and virtually no mortality. The 96% survival in this series of benign liver tumors contrasts with high mortality rates reported in the literature and illustrates the spectacular improvements that have been made in the diagnosis and management of these once ill-reputed tumors.