Pneumomediastinum in blunt trauma: If aerodigestive injury is not seen on CT, invasive workup is not indicated.

BACKGROUND: Pneumomediastinum following blunt trauma is often observed on CT imaging, and concern for associated aerodigestive injury often prompts endoscopy and/or fluoroscopy. In recent years, adoption of multi-detector CT technology has resulted in high resolution images that may clearly identify aerodigestive injuries. The purpose of this study was to evaluate the utility of multi-detector CT in the identification of blunt aerodigestive injuries. METHODS: Over five years, patients with pneumomediastinum following blunt trauma were identified from the registry of a level 1 trauma center. All CT imaging of trauma patients during this time period was accomplished with 64-slice scanners. RESULTS: 127 patients with blunt traumatic pneumomediastinum were identified. Five airway injuries were identified, and all injuries were evident on CT imaging. No patient was found to have airway injury by endoscopy that was not evident on CT. No patient had an esophageal injury. CONCLUSION: Multi-detector CT imaging identifies aerodigestive injuries associated with pneumomediastinum following blunt trauma. The absence of a recognizable aerodigestive injury by CT effectively rules out the presence of such injury.

Visceral and gastrointestinal complications in robotic urologic surgery. / Complicaciones viscerales y gastrointestinales en la cirugía urológica robótica.

INTRODUCTION: with the widespread use of minimally invasive techniques, robot-assisted urologic surgery has become widely adopted. Despite their infrequency, visceral and gastrointestinal complications could be life-threatening. OBJECTIVES: To identify the main gastrointestinal injuries that occur in a robot-assisted urologic surgery. To know the overall incidence and how is their management. ACQUISITION OF THE EVIDENCE: Search in PubMed of articles related to visceral and gastrointestinal complications in robot-assisted urology surgery, written in English or Spanish. Relevant publications as well literature reviews and chapters from books were reviewed. SYNTHESIS OF THE EVIDENCE: Along with vascular injuries, visceral and gastrointestinal lesions are among most dangerous complications. A complete preoperative study to individualize each patient characteristics and the correct use of imaging could help us to avoid complications in the first place. To know all the risky steps in the different robotic urologic procedures will let us anticipate the damage. Knowledge of main and most dangerous injuries in the different abdominal and pelvic organs is fully recommended. Early diagnosis and evaluation of lesions will let us an acute management during surgery. Recognition delay could change a repairable injury into a life-threatening situation. CONCLUSIONS: Despite the undeniable benefits of robotic approach, there are minor and major gastrointestinal injuries that all urologic surgeons must know. Those related with trocar placement are especially important. Immediate diagnosis and management is mandatory.

General surgeon management of complex hepatopancreatobiliary trauma at a level I trauma center.

BACKGROUND: The impact of general surgeons (GS) taking trauma call on patient outcomes has been debated. Complex hepatopancreatobiliary (HPB) injuries present a particular challenge and often require specialized care. We predicted no difference in the initial management or outcomes of complex HPB trauma between GS and trauma/critical care (TCC) specialists. MATERIALS AND METHODS: A retrospective review of patients who underwent operative intervention for complex HPB trauma from 2008 to 2015 at an ACS-verified level I trauma center was performed. Chart review was used to obtain variables pertaining to demographics, clinical presentation, operative management, and outcomes. Patients were grouped according to whether their index operation was performed by a GS or TCC provider and compared. RESULTS: 180 patients met inclusion criteria. The GS (n = 43) and TCC (n = 137) cohorts had comparable patient demographics and clinical presentations. Most injuries were hepatic (73.3% GS versus 72.6% TCC) and TCC treated more pancreas injuries (15.3% versus GS 13.3%; P = 0.914). No significant differences were found in HPB-directed interventions at the initial operation (41.9% GS versus 56.2% TCC; P = 0.100), damage control laparotomy with temporary abdominal closure (69.8% versus 69.3%; P = 0.861), LOS, septic complications or 30-day mortality (13.9% versus 10.2%; P = 0.497). TCC were more likely to place an intraabdominal drain than GS (52.6% versus 34.9%; P = 0.043). CONCLUSIONS: We found no significant differences between GS and TCC specialists in initial operative management or clinical outcomes of complex HPB trauma. The frequent and proper use of damage control laparotomy likely contribute to these findings.

Conservative management of severe caustic injuries during acute phase leads to superior long-term nutritional and quality of life (QoL) outcome.

PURPOSE: Best clinical management of severe caustic injury is still a subject of debate. Most surgical teams consider severe caustic injury as an indication for emergency surgery. But, under certain circumstances, conservative management is feasible, avoids the need for gastrectomy, and has a low mortality rate. Postponed reconstructive surgery is usually performed several months after caustic ingestion to restore intestinal continuity or to treat stricture sequelae. This study aimed to investigate long-term nutritional and quality of life (QoL) outcomes after reconstructive surgery for high-grade esophageal and gastric caustic injury. METHODS: Twenty-one patients were assessed for biological and nutritional parameters, physical findings, and quality of life surveys at least 25 months after reconstructive surgery among patients who have required emergency surgery (n = 10) and patients who did not undergo emergency surgery (n = 11). RESULTS: After median follow-up of 74 months (after caustic ingestion) and 67 months (after reconstructive surgery), patients who avoided emergency surgery experienced faster oral diet resumption (49 vs. 157 days, p = 0.004), less weight loss (0.3 vs. 20 kg, p = 0.002), greater body fat percentage (22 vs. 18 %, p = 0.046), better nutritional and physical status (SF12 PCS 51 vs. 43, p = 0.036), and less trouble eating (EORTC QLQ-OG 25 31 vs. 56, p = 0.01). CONCLUSIONS: Our study is the first to evaluate long-term nutritional and QoL outcomes, following severe caustic injury. It demonstrates better long-term nutritional outcomes and QoL in patients suitable for initial conservative management. These results support full functional recuperation of spared organs, even severely burned. In the absence of clinical or biological signs necessitating immediate surgery, conservative management should be advocated.

Pneumomediastinum following blunt trauma: Worth an exhaustive workup?

BACKGROUND: Incidental pneumomediastinum is a common radiologic finding following blunt thoracic injury; however, the clinical significance of pneumomediastinum on screening imaging is poorly defined (Curr Probl Surg. 2004;41(3):211-380; Injury. 2010;41(1):40-43). The purpose of this study was to define the incidence of aerodigestive injuries in patients with pneumomediastinum after blunt thoracic and neck injury. METHODS: After institutional review board approval was obtained, a retrospective review was performed of all patients admitted to Los Angeles County + University of Southern California Medical Center with blunt neck and/or thoracic injuries between January 2007 and December 2012. All patients with pneumomediastinum on radiologic investigation were included. Data accrued included demographics, admission clinical data, injury severity patterns, incidence of aerodigestive injuries, operative findings, morbidity, mortality, as well as intensive care unit and hospital lengths of stay. RESULTS: A total of 9,946 patients were included in the study. The predominant mechanism was motor vehicle collision (49%), disproportionately male (76%). Overall, 258 patients (2.6%) had a pneumomediastinum: 65 (25%) and 193 (75%) were diagnosed on a chest x-ray or on a computed tomography (CT) scan, respectively. A total of 21 patients (8.1%) had an aerodigestive workup with bronchoscopy, esophagram, and/or esophagoscopy. Overall, four aerodigestive lesions (1.6%) were diagnosed. Three tracheobronchial injuries were identified on CT scan, and one esophageal injury was diagnosed on an esophagram. Two tracheobronchial injuries required surgery, while the remaining cases were managed nonoperatively. The overall mortality in this cohort was 10.9%. CONCLUSION: Isolated findings of pneumomediastinum on screening chest x-ray or CT following blunt trauma is a poor predictor of an aerodigestive injury. Highly selective workup in this clinical setting is warranted. LEVEL OF EVIDENCE: Prognostic/epidemiologic study, level III; therapeutic study, level IV.

Perforations following endoscopic retrograde cholangiopancreatography: a single institution experience and surgical recommendations.

BACKGROUND: Perforation after endoscopic retrograde cholangiopancreatography (ERCP) is uncommon, and its management is dependent on the mechanism and the graded classification of injury. METHODS: Records of patients undergoing ERCP were analyzed over a 16-year period, patterning the types of injuries, diagnosis, management, and patient outcome. Type I injuries damage the medial or lateral duodenal wall before sphincter cannulation. Type II injuries are periampullary and occur as a result of a precut or a papillotomy. Type III injuries occur secondary to guidewire insertion or stone extraction from the common bile duct. Type IV injuries are probably microperforations that are noted on excessive insufflation during and after ERCP withdrawal. RESULTS: Between 1995 and 2011, 27 perforations were identified from 1,638 ERCP procedures (1.6%). Nearly half of the procedures were regarded as difficult by the endoscopist, with 70% of the ERCPs (19 of 27) being for therapeutic indications. There were 5 type I, 12 type II, 5 type III, and 5 type IV perforations, of which 18 cases were diagnosed at the time of ERCP. Delayed diagnosis of type I perforations that were associated with free intraperitoneal air and contrast leakage proved fatal. Most type II perforations required immediate surgery with pyloric exclusion; delayed surgery with simple drainage had a high mortality rate. Most type III and type IV injuries can successfully be managed conservatively without delayed sepsis. CONCLUSIONS: In perforation, the mechanism of injury during ERCP predicts the need for surgical management. Type I and type II injuries require early diagnosis and aggressive surgery, whereas type III and type IV injuries may be managed conservatively.

[Experience of open renal trauma in a urology service]. / Experiencia de traumatismo renal abierto en un servicio de urología.

INTRODUCTION: Opened renal trauma in urban areas reaches 15 to 20% of all renal traumas. It is mainly caused by gunshot wounds or knifes. Gunshot wounds are classified as high energy trauma and are usually associated to other organ injuries. We present our experience in opened renal trauma in the last 24 months. MATERIAL AND METHODS: Retrospective study: patients with thoracic, abdominal and thoraco-abdominal trauma admitted to the emergency room between July 2009 and June 2011 were studied. Fourteen patients were identified with opened renal trauma, with diagnostic confirmation by imaging study or during surgery. RESULTS: Ages ranged from 16 to 37 years, with a mean age of 24.5 years. Thirteen patients were males. The mechanism of injury was produced by gunshot in 71% (10/14) and by knife in 29% (4/14). The opened renal traumas were classified according to the American Association for the Surgery of Trauma. Of these, 3/14 (21%) belonged to grade II, 4/14 (29%) to grade III, 4/14 (29%) to grade IV and 3/14 to grade V (21%). Fall in hematocrit ranged from 1% to 27%, with an average of 13.9%. Expectant management was done in six patients, however, this management did not take into account those surgeries performed due to non-urologic organ injuries. Six patients (42%) required nephrectomy. Thoraco-abdominal injuries were associated in 11 patients (79%). CONCLUSIONS: Despite the low incidence of opened renal trauma, many patients are observed when other national reports are considered, probably due to the socio-cultural characteristics of this hospital.

Esophagogastroduodenoscopy-associated gastrointestinal perforations: a single-center experience.

BACKGROUND: Esophagogastroduodenoscopy (EGD) is commonly used in the diagnosis and treatment of gastrointestinal (GI) disorders. Our aim was to define the risk of perforation associated with EGD and identify patients who required operative intervention. METHODS: We retrospectively reviewed 72 patients from our institution plus 5 transferred patients who sustained EGD-associated perforations from January 1996 through July 2008. Percutaneous endoscopic gastrostomy, endoscopic ultrasonography, endoscopic retrograde cholangiopancreatography, transthoracic echocardiography, and concurrent colonoscopy procedures were excluded. RESULTS: Perforations in 72 of 217,507 EGD procedures were identified (incidence, 0.033%); 124,844 EGDs included an interventional procedure and 92,663 were examination only. The incidence of perforation was similar whether an interventional procedure was performed or not (0.040% vs 0.029%; P = .181). The esophagus was injured most commonly (51%), followed by the duodenum (32%), jejunum (6%), stomach (3%), and common bile duct (3%). Overall mortality after perforation was 17% with a morbidity rate of 40%. Thirty-eight patients (49%) were initially treated nonoperatively, 7 of whom (18%) failed nonoperative management. The only factors we could determine that were associated with failure were free fluid or contrast extravasation on computed tomography (75% vs 23% [P < .005] and 33% vs 0% [P = .047], respectively). The morbidity of failures was equivalent to those who underwent initial operative management (63% vs 61%; P = .917), with mortality seeming to be greater (43% vs 21%; P = .09). CONCLUSION: EGD is safe in the majority of patients; however, iatrogenic perforation is associated with considerable morbidity and mortality. Nonoperative management of GI perforation can be successful if there is no evidence of contrast extravasation or free fluid on radiographic studies. If nonoperative management fails, the outcomes may be worse than those treated initially with operative repair.

La colonoscopia: ¿es un estudio pre-operatorio indispensable para la restitución del tránsito intestinal en pacientes jóvenes: portadores de colostomía por traumatismo abdominal penetrante? / Colonoscopy: is a necessary pre-operatory study for intestinal transit restitution in young patients carrying a colostomy by penetrating abdominal trauma?

Determinar el impacto de la colonoscopia como procedimiento preoperatorio requisito para la restitución del tránsito intestinal en una población portadora de colostomía por un traumatismo abdominal penetrante. Estudio descriptivo, retrospectivo observacional, donde se evalúan informes de endoscopias digestivas inferiores realizadas por el servicio de Gastroenterología del Hospital General del Oeste "Dr. José Gregorio Hernández" de Caracas, como requisito preoperatorio para la restitución del transito intestinal en pacientes portadores de colostomía por traumatismo abdominal penetrante, en el período comprendido entre enero 2004 y diciembre 2008. De una población total de 46 pacientes, se les realizó una colonoscopia a 34 (73,91%). Los 12 restantes (26,08%), no cumplían con los criterios de inclusión. de los 34 pacientes incluidos para evaluación, 22 (64,70%), presentaron colitis y recidivas por deprivación, 7 (20,59%) con estudio normal y 4 (11,76%) presentaron alguna alteración en la endoscopia digestiva inferior. En este estudio no hay evidencia que sugiera que la realización de una colonoscopia preoperatoria en la cirugía electiva de restitución de tránsito intestinal, evite la aparición de complicaciones, ni permita el diagnóstico de patologías de relevancia en la población estudiada, no teniendo ésta la importancia que se le ha otorgado hasta la actualidad.

To determine the impact of the colonoscopy as pre-operating procedure as a requirement in the population carrying of colostomy by abdominal penetrating trauma for the restitution of the intestinal transit. Descriptive, retrospective and observational study, where the inferior digestive endoscopy made by the service of Gastroenterology in Hospital General del Oeste "Dr. José Gregorio Hernández", Caracas, was valued as pre-operating requirement in carrying patients of colostomy by abdominal penetrating trauma for the restitution of the intestinal transit, in the period between January 2004 to December 2008. In a population of 46 patients, only 34 (73.91%) were included to do the colonoscopy, the others 12 (26,08%) didn't fulfill the inclusion criteria. Of the 34 patients included, 22 (64.70%) were displayed colitis and rectitis by deprivation, 7 (20.59%) were normal study and 4 (11.76%) presented others alteration in the inferior digestive endocopy. In this study there is not evidence to suggest that the realization of preoperatory colonoscopy for surgery in the restitution of intestinal transit, avoid complications or permit diagnosis of diseases in the study population, doing less important the evidence exposed until present.

Caustic ingestions in children.

PURPOSE OF REVIEW: The purpose of this review is to outline the current epidemiology, mechanism of injury, clinical manifestations, management and long-term complications of caustic ingestions in pediatric patients. RECENT FINDINGS: Recent data suggest that more than 200 000 exposures to household or industrial cleaning products occur annually in the United States. It is difficult to determine what fraction of these exposures represents caustic ingestions. Caustic ingestions occur most commonly in children less than age 6 years. Because of the accidental nature of the ingestions, the case fatality rate for pediatric patients is significantly less than that of adolescents and adults. Despite laws to limit the concentration of household cleaning products, farm and industrial products and products stored in nonoriginal containers represent a significant source of caustic agents. Endoscopy remains the preferred method of staging injury. In children the absence of symptoms does not predict lack of relevant injury. However, the presence of three or more symptoms is associated with a high likelihood of significant injury. Long-term complications in pediatric patients may be severe and include esophageal cancer. SUMMARY: Caustic ingestions remain a significant cause of pediatric morbidity in the United States and abroad. Endoscopy is the primary method of staging injury following a caustic ingestion. Extent of injury at initial evaluation remains the best predictor of morbidity and mortality in pediatric patients following an accidental caustic ingestion.

Clinical characteristics and complications in oral caustic ingestion in children.

The aim of this study is to evaluate the prevalence of gastrointestinal symptoms in caustic ingestion, the severity of lesions and the role of early conducted endoscopy in prediction of outcome. In a cross-sectional study all children hospitalized for caustic ingestion during two years, aged 12 years and younger were evaluated for clinical history, endoscopic findings, method of treatment and observed complications. Out of 51 children, 8 consumed acidic and 43 alkaline materials. The mean age of the children was 35.9 +/- 18 months. Thirty four (66.7%) patients were male and 17 (33.3%) were female. In endoscopic survey, 38% had grade 1 and 62% had a burning intensity of grade 2 or higher. During the follow-up, esophageal structure developed in 5 cases and Gastric Outlet Obstruction (GOO) in 1 case. Two of 5 patients with stricture were treated by endoscopic dilatation and 3 of them underwent colon transposition surgery. Gastrectomy was done for the patient with GOO. Esophageal structure as a complication had a more incidence in acid ingestion. Gastric Otlet Obstruction (GOO) occurred in a case of acid ingestion. One of the patients died. Positive statistical relation between early endoscopic findings and complications found in control endoscopy suggest that early endoscopy probably is safe and provides important prognostic information. The role of prevention as a comprehensive strategy promoted by medical councils and the mass media is imperative.

Stents metálicos autoexpansibles de vías digestivas: experiencia, complicaciones y manejo endoscópico / Slef expandable metal stents of gastric tracts: experience, complications and management

Los stents metálicos autoexpansibles han sido ampliamente utilizados en los últimos años para paliación de síntomas obstructivos secundarios a enfermedad maligna de vías digestivas. Se presenta la experiencia y el manejo de complicaciones en la Unidad de Exploraciones Digestivas del Hospital de Clínicas Caracas. Se colocaron 60 stents metálicos autoexpansibles por estenosis malignas en pacientes con enfermedad avanzada: 22 en esófago, 8 en estómago, 8 en duodeno, 5 en colon y 17 en vías biliares. Se logró paliación de los síntomas en todos los casos. Se presentaron complicaciones en el 33 por ciento. Estas fueron manejadas endoscópicamente en el 92 por ciento de los casos. Las prótesis metálicas autoexpansibles son una alternativa eficiente en la paliación de estenosis malignas de vías digestivas en pacientes con enfermedad avanzada. El endoscopista debe conocer minuciosamente las indicaciones, los detalles de los sistemas de colocación y los mecanismos de liberación de los dispositivos para minimizar las posibles complicaciones. La mayoría de las complicaciones pueden ser manejadas endoscopicamente

Presencia de helicobacter pylori en mucosa gástrica en pacientes VIH+ y VIH- con síntomas gastrointestinales altos / Presence of helicobacter pylori in HIV positive and negative patients with upper gastrointestinal symptoms

El sistema gastrointestinal alto se encuentra comprometido frecuentemente en los pacientes infectados por VIH, sintomas como náuseas, vómitos, epigrastralgia, llenura post prandial, son referidos por los pacientes. En ellos, la mucosa gastrointestinal esta constantemente agredida por el uso de fármacos y agentes infecciosos entre los que se encuentra el Helicobacter pylori (Hp). La infección por Hp es alta en países en desarrollo e inversamente proporcional al status socio-económico. La prevalencia de Hp es muy variable, por lo que se ideó este proyecto con el objeto de relacionar la presencia de Hp en pacientes con síntomas del tracto gastrointestinal superior en la población seropositiva y seronegativa para el virus de inmunodeficiencia. 54 pacientes fueron estudiados a través de endoscopia digestiva superior y biopsia de antro gástrico. De los cuales 27 pacientes fueron VIH+, subdividiéndolo de acuerdo al contaje celular (TCD4) en grupo A menor de 200 cel/1, grupo B mayor de 200 cel/1, y el restante 27 casos (50 por ciento) seronegativos se llamó grupo C. Género masculino 35 casos (64,8 pór ciento), femenino 19 (35,2 por ciento). De acuerdo a la sintomatología 44 presentaron epigastralgia (80.4 por ciento), dolor abdominal 9 (16.6 por ciento), disfagia 7 (12.9 por ciento), llenura post pradial 6 casos (11.1 por ciento). Endoscopia: reportó gastritis antral en: grupo A, 8 casos (88,8 por ciento), grupo B, 17 casos (94,4 por ciento) y grupo C, 27 casos (100 por ciento). Al estudio histopatológicvo se encontró gastritis crónica: grupo A,8 casos (88,8 pór ciento), grupo B, 17 (94,4 por ciento), y el grupo C el 100 por ciento de los casos (27 paicentes). En cuanto al Hp, este estuvo positivo en : grupo A, 7 casos (77,7 por ciento), grupo B, 16 casos (88,8 por ciento), y grupo C, 14 pacientes (51.8 por ciento). La prevalecencia de Hp en mucosa gástrica en pacientes con síntomas gastrointestinales superiores en VIH + fue mayor que lo reportado en VIH-

Management of cervical aerodigestive injuries.

The management of patients with cervical injuries is highly controversial. Some authorities advocate mandatory exploration for all such injuries, while others advocate selective exploration. This paper will objectively review the evidence supporting each approach. The non-operative approach may be pursued through a variety of diagnostic modalities and this paper will also review the evidence supporting their use in cervical trauma. A clear understanding of these modalities and their relative merits is mandated by the potential severity of cervical injuries and their need for rapid intervention.

Corrosive ingestion in adults.

Ingestion of a corrosive substance can produce severe injury to the gastrointestinal tract and can even result in death. The degree and extent of damage depends on several factors like the type of substance, the morphologic form of the agent, the quantity, and the intent. In the acute stage, perforation and necrosis may occur. Long-term complications include stricture formation in the esophagus, antral stenosis and the development of esophageal carcinoma. Endoscopy should be attempted and can be safely performed in most cases to assess the extent of damage. Procedure-related perforation is rare. Stricture formation is more common in patients with second and third degree burns. Corticosteroids may help prevent stricture formation. Esophageal carcinoma may develop beginning 30 to 40 years after the time of injury.

Immunonutrition: problematic or problem solving?

The addition of immune-modulating nutrients to enteral formulas has been examined in clinical trials and meta-analyses. Enhancing immunity through diet is generally done by adding n-3 fatty acids, arginine, and nucleotides to an otherwise nutritionally complete formula. Despite flaws in many studies, a consistent trend to reduced infectious complications has been seen with immunonutrition, especially in patients undergoing surgery for upper gastrointestinal cancer or trauma. In critical care populations, however, the results have been mixed. In this review, we analyze these studies and focus on select clinical points that may explain the variation. One common flaw has been a failure to deliver an adequate nutrition volume. Few patients, especially in the earliest studies, received even close to goal feeding. A minimum quantity of immunonutrition may be required for effective reduction in infections. When feeding volumes are low, immunonutrition is usually not better than an isonitrogenous control. In more recent studies, practitioners have been increasingly aggressive with enteral feeding, and this has been reflected in improved outcomes from immunonutrition. Early delivery of immunonutrition (preoperatively in surgical patients with cancer) might be particularly beneficial. Another consideration is illness severity: we discuss evidence that the use of immunonutrition in moderate illness is more likely to be helpful, whereas severe sepsis is probably beyond the reach of any nutritional intervention, and mild illness is more likely to improve irrespective of feeding. If future trials can consider these vital points, level 1 recommendations in favor of immunonutrition might be justified, although presently such evidence is lacking for most clinical indications.

How safe is high-power ultrasonic dissection?

OBJECTIVE: To evaluate the safety of ultrasonic dissection. SUMMARY BACKGROUND DATA: High-power ultrasonic dissection is in widespread use for both open and laparoscopic operations and is generally perceived to carry a low risk of collateral damage, but there is no published evidence for this. METHODS: Under controlled experimental conditions, ultrasonic dissections were performed in pigs using Ultracision (Ethicon) or Autosonix (Tyco/USSC) at the three power settings (3, 4, and 5) in random fashion to mobilize the cardia and fundus, bile duct, hepatic artery, portal vein, aorta from the inferior vena cava, renal vessels, colon, and ureters. The dissections (open and laparoscopic) were carried out on pigs at each power setting with each device. Thermal mapping of the tissues during dissection was performed with an infrared thermal camera and associated software. The animals were killed at the end of each experiment and specimens were harvested for quantitative histology. RESULTS: Extreme and equivalent temperature gradients were generated by ultrasonic dissection with both systems. Heat production was directly proportional to the power setting and the activation time. The core body temperature of the animals after completion of the laparoscopic dissections rose by an average of 2.3 degrees C. The zone around the jaws that exceeded 60 degrees C with continuous ultrasonic dissection for 10 to 15 seconds at level 5 measured 25.3 and 25.7 mm for Ultracision and Autosonix, respectively. At this power setting and an activation time of 15 seconds, the temperature 1.0 cm away from the tips of the instrument exceeded 140 degrees C. Although there was no discernible macroscopic damage, these thermal changes were accompanied by significant histologic injury that extended to the media of large vessels and caused partial- to full-thickness mural damage of the cardia, ureter, and bile duct. Collateral damage was absent or insignificant after dissections at power level 3 with both systems and an activation time not exceeding 5 seconds. CONCLUSIONS: High-power ultrasonic dissections at level 5 and to a lesser extent level 4 result in considerable heat production that causes proximity collateral damage to adjacent tissues when the continuous activation time exceeds 10 seconds. Ultrasonic dissections near important structures should be conducted at level 3. At power levels of 4 and 5, the ultrasonic energy bursts to the tissue should not exceed 5 seconds at any one time.