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All-comers policy for laparoscopic exploration of the common bile duct.

BACKGROUND: Laparoscopic exploration of the common bile duct is associated with substantial variation in results suggesting that different patient populations are being reported. This report observes the results in a defined population and on an intention-to-treat basis. METHODS: All patients with suspected bile duct stones who were fit for surgery from April 1994 were offered laparoscopic bile duct exploration. There were 224 patients of mean age 56 years, of whom 174 were women. Endoscopic sphincterotomy was used in 149 patients deemed unfit for surgery. All data were recorded prospectively and checked at the time of discharge. Patients were followed up after 6 months and beyond after the operation. RESULTS: Stones were removed transcystically in 56 patients, transductally in 158 and by flushing in nine. The duct clearance rate was 96 per cent overall, 98 per cent for transcystic and 94 per cent for transductal exploration. Intracorporeal lithotripsy safely reduced the failure rate of exploration from seven of the first 28 to four of the subsequent 196 procedures. Biliary complications occurred in 16 per cent of procedures in which a T tube was used but only 4 per cent if the duct was closed by suturing. Conversion to open operation for severe gallbladder inflammation was necessary in 6 per cent of patients. There were no deaths, bile duct injuries or pancreatitis but complications occurred in 19 per cent, associated with use of T tubes and advancing age. Laparoscopic duct exploration succeeded in seven patients after previous cholecystectomy. CONCLUSION: Laparoscopic bile duct exploration is effective and safe when used for all patients. For young and fit patients it should replace endoscopic sphincterotomy.

Adolescent↗

Comparison of bilateral whisker movement in freely exploring and head-fixed adult rats.

Rats move their whiskers actively during tactile exploration of their environment. The whiskers emanate from densely innervated whisker follicles that are moved individually by intrinsic facial muscles and as a group by extrinsic muscles. Several descriptions of whisker movements in normal adult rats during unrestrained exploration indicate that rats move their whiskers in the 6-9 Hz range when exploring a new environment. The rate can be elevated to nearly 20 Hz for brief episodes just prior to making a behavioural decision. The present studies were undertaken to compare whisker dynamics in head-restrained and freely moving rats with symmetrical or asymmetrical numbers of whiskers on the two sides of their face and to provide a description of differences in whisker use in exploring rats after trimming all but two whiskers on one side of the face, a condition that has been shown to induce robust cortical plasticity. Head-fixed rats were trained to protract their whiskers against a contact detector with sufficient force to trigger a chocolate milk reward. Whisker movements were analyzed, and the results from head-fixed animals were compared with free-running animals using trials taken during their initial exploration of novel objects that blocked the rat's progress down an elevated runway. The results show that symmetrical whisker movements are modulated both by the nature of the task and the number of whiskers available for exploration. Rats can change their whisker movements when the sensitivity (threshold) of a contact detector is raised or lowered, or when the nature of the task requires bilateral input from the whiskers. We show that trimming some, but not all whiskers on one side of the face modifies the synchrony of whisker movement compared to untrimmed or symmetrically trimmed whiskers.

Animals↗

NASA's new Mars Exploration Program: the trajectory of knowledge.

NASA's newly restructured Mars Exploration Program (MEP) is finally on the way to Mars with the successful April 7 launch of the 2001 Mars Odyssey Orbiter. In addition, the announcement by the Bush Administration that the exploration of Mars will be a priority within NASA's Office of Space Science further cements the first decade of the new millennium as one of the major thrusts to understand the "new" Mars. Over the course of the past year and a half, an integrated team of managers, scientists, and engineers has crafted a revamped MEP to respond to the scientific as well as management and resource challenges associated with deep space exploration of the Red Planet. This article describes the new program from the perspective of its guiding philosophies, major events, and scientific strategy. It is intended to serve as a roadmap to the next 10-15 years of Mars exploration from the NASA viewpoint. [For further details, see the Mars Exploration Program web site (URL): http://mars.jpl.nasa.gov]. The new MEP will certainly evolve in response to discoveries, to successes, and potentially to setbacks as well. However, the design of the restructured strategy is attentive to risks, and a major attempt to instill resiliency in the program has been adopted. Mars beckons, and the next decade of exploration should provide the impetus for a follow-on decade in which multiple sample returns and other major program directions are executed. Ultimately the vision to consider the first human scientific expeditions to the Red Planet will be enabled. By the end of the first decade of this program, we may know where and how to look for the elusive clues associated with a possible martian biological record, if any was every preserved, even if only as "chemical fossils."

Mars↗

Inguinal hernias in pediatrics: initial experience with laparoscopic inguinal exploration of the asymptomatic contralateral side.

Laparoscopic inguinal "exploration" was undertaken in 22 consecutive pediatric patients to assess the value of this technique in detecting the presence or absence of occult inguinal hernias on the asymptomatic side of patients with unilateral disease. After a CO2 pneumoperitoneum was established using a Veress needle, a 2 mm 0 degree laparoscope was passed via a 3 mm cannula and both inguinal rings were inspected. Eleven cases (50%) had previously unsuspected bilateral disease diagnosed at laparoscopy and had bilateral inguinal hernias confirmed at exploration. Nine cases, in which the asymptomatic side was assessed as being negative at laparoscopy, were confirmed negative by open exploration. In one misdiagnosed case of bilateral hernias, no hernias were found at laparoscopy and one side had a non-communicating hydrocele at exploration. There was one failure, an infant less than 2 months of age, in whom the inguinal anatomy could not be adequately visualized at laparoscopy and a hernia was found at exploration. There were no complications. Thus, laparoscopic inguinal "exploration" was 96% accurate in this initial evaluation. The adoption of this approach to the assessment of the asymptomatic contralateral side in infants with unilateral hernias would eliminate many inguinal operations and the complications associated with unnecessarily manipulating the delicate cord structures.

Child↗

Directional bias of initial visual exploration. A symptom of neglect in Parkinson's disease.

In the present study, side preferences in spontaneous visual exploration were assessed systematically in 27 patients with idiopathic Parkinson's disease (IPD) and 17 age-matched controls. Assessment of initial visual exploration asymmetry (IVE) was based on the exploration of texture arrays requiring attentive oculomotor scanning. As shown in a previous study, most healthy subjects exhibit a marked asymmetry of IVE with a strong left-sided bias when assessed by this paradigm, while most neglect patients initiate exploration in the right half of the arrays. Standard assessments for symptoms of neglect (line bisection, line cancellation and double simultaneous stimulation) were performed as reference tests. In the IVE task 65% of normal controls and 69% of patients with predominantly right-sided IPD started exploration in the left half of the arrays. By contrast only 14% of patients with predominantly left-sided disease showed a leftward IVE. The majority shows an ambiguous (21%) or rightward (64%) directional bias for initial exploration and thus a behaviour that corresponds to the IVE abnormalities found in neglect patients. No abnormalities were found in the standard neglect tests in any of the groups. The atypical IVE in patients with predominantly left-sided Parkinson's disease should be interpreted in the context of recent concepts of attention postulating that a bias in early spontaneous orientation directed to the ipsilesional hemifield reflects a mild and residual manifestation of hemineglect. Since this subtle orientational bias is less subject to compensation than more conspicuous clinical signs of neglect, sensitivity is higher in IVE testing than in conventional neglect assessments in chronic disorders with subclinical neglect. The present findings contribute a new aspect to the complex picture of cognitive and visuospatial abnormalities in Parkinson's disease. Furthermore our results extend previous knowledge on the mechanisms of neglect and the role of dopamine in the mediation of attention.

Aged↗

Reassessment of the role of routine operative exploration in vascular trauma.

During the 5-year period ending December 1978, 390 patients were explored for suspected vascular injury either in the neck or in one of the extremities with 13% morbidity and a 1% mortality rate. Positive exploration for vascular injury in 139 patients (36%) resulted in 28% morbidity and 2% mortality. Negative exploration in 251 patients (64%) was associated with a 5% morbidity and 0.4% mortality. Per cent positive exploration by type of injury was: iatrogenic injury (100%), foreign body laceration (100%), blunt trauma (79%), stab wound (32%), and gunshot wound (31%). Per cent positive exploration by area was: brachium (68%), popliteal area (63%), femoral area (28%), axilla (27%), and neck (25%). Routine exploration of patients at risk for vascular injury can be accomplished with minimal morbidity and mortality but is associated with a low (36%) diagnostic yield. 'Exclusion' arteriography in hemodynamically stable patients with equivocal signs of vascular injury appears to be indicated to increase diagnostic accuracy.

Adolescent↗

Directed parathyroid exploration: evolution and evaluation of this approach in a single-institution review of 346 patients.

OBJECTIVES/HYPOTHESIS: Critical evaluation of a directed exploration protocol used by a single surgeon in the management of surgical parathyroid disease. STUDY DESIGN: Retrospective chart review was made of patients surgically managed for hyperparathyroidism at an academic tertiary care center. METHODS: Three hundred forty-six patients were evaluated for biochemically proven hyperparathyroidism between March 1995 and February 2002. A directed exploration protocol was implemented in appropriately selected patients with primary hyperparathyroidism and in patients with secondary or tertiary hyperparathyroidism requiring repeat operation. The protocol included preoperative technetium-99m sestamibi imaging for hyperfunctional parathyroid localization, targeted neck exploration, rapid intraoperative parathyroid hormone determination, and limited-stay discharge from the ambulatory surgical recovery unit. Data collection was accomplished by entering patient evaluation, management, and outcome information prospectively into collective case report forms. A retrospective analysis of the data was conducted for the purpose of evaluating the effectiveness of the protocol. RESULTS: Sustained normocalcemia beyond 6 months postoperatively was achieved in 323 of 327 (99%) patients with primary hyperparathyroidism. Eighty-four percent (84%) of patients with secondary or tertiary hyperparathyroidism achieved normocalcemia or had resolution of symptoms as a measure of therapeutic success. The complication rate for the entire series of patients was 2.8%. Ninety-two percent of positive findings on sestamibi scan correctly predicted the location of an adenoma, whereas a negative finding accurately predicted the absence of an enlarged gland in a "usual" location in 81% of patients. Twenty-six patients (9%) had a false-positive finding on the scan, whereby a solitary adenoma was found contralateral to the side indicated by the scan. Overall, the positive predictive value for sestamibi imaging in the series was 91%. Intraoperative parathyroid hormone determination yielded an overall rate of reduction of 80% from preoperative levels during directed exploration. Sustained normocalcemia was achieved in all patients in whom intraoperative parathyroid hormone determination demonstrated a minimum decline of 50% from preoperative levels following resection of hyperfunctional parathyroid tissue (adenoma[s]). The majority (72%) of patients were managed in an outpatient (ambulatory surgery) setting and were discharged to home within 8 to 12 hours after surgery. CONCLUSION: The directed exploration protocol for surgical management of hyperparathyroidism generated surgical rates of success that were as good as and, in most cases, improved over that of traditional bilateral exploration. This achievement was associated with low morbidity and reduced time and facility utilization, conveying improved cost-effectiveness. This surgical strategy should serve to enhance the capability of the surgeon to safely and efficiently manage the majority of patients with surgical parathyroid disease.

Adolescent↗

Penetrating neck injuries: experience with selective exploration.

Although many authors have stated that surgical exploration should be mandatory for all neck wounds that penetrate the platysma, recent reports from many centers now claim that selective exploration is both safe and reasonable. A policy of selective exploration based on clinical presentation, anatomic location, and results of diagnostic studies has been followed at The Cooper Green Hospital in Birmingham, Alabama, for the past 13 years. We report a study of penetrating neck wounds in 136 consecutive patients admitted to The Cooper Green Hospital from 1972 to 1984. Seventy-seven patients (57%) had exploration immediately, with one death, while the remaining 59 (43%) were admitted and observed. Of these 59 patients, ten had arch aortography and nine had esophagography, all of which yielded normal results. The remainder of the patients observed had no clinical signs or symptoms to suggest a major injury. There were no deaths or complications related to the neck wounds in the 59 patients observed. Results of 27 explorations (35%) were negative. We conclude that selective exploration of penetrating neck wounds is both safe and reasonable.

Adolescent↗

Diagnostic and therapeutic laparoscopy for trauma: a technique of safe and systematic exploration.

Laparoscopy has a limited role in the evaluation of a stable trauma patient. The main concern addressed in the literature is a significant potential for missed visceral injury and a minimal role for therapeutic application. We present a simple technique for systematic abdominal exploration for a suspected intraabdominal injury in a series of three consecutive trauma patients (two penetrating injuries, one blunt) at a level-one trauma center. Three 5-mm ports and a 30-degree laparoscope were used for exploration. Additional ports for retraction were used as needed for therapeutic procedures. All patients underwent complete exploration of the abdominal cavity. Therapeutic procedures consisted of suturing an intraperitoneal bladder rupture, draining a lacerated tail of the pancreas, and cauterizing an actively bleeding penetrating wound to the left lobe and caudate lobe of the liver. All patients experienced prompt and uncomplicated recovery. There were no missed injuries. The presented technique enables a systematic laparoscopic exploration of the abdomen, which follows the same principles as open exploration. The role of laparoscopy in the treatment of a stable trauma patient is likely to increase as more surgeons acquire advanced laparoscopic skills, and as systematic exploration techniques are used.

Accidents, Traffic↗

Dorsal vein injuries observed during penile exploration for suspected penile fracture.

INTRODUCTION: Penile fracture is a rare injury, bearing potential impairment of erectile function if not treated. Patients with clinical presentation of a penile fracture commonly undergo early surgical exploration with the intention to repair a tunica albuginea tear. AIM: We present a group of men who presented with a penile hematoma following trauma to the erect penis. Exploration revealed an intact tunica albuginea and a dorsal vein tear. METHODS: Eighteen men (mean age 38 years, range 20-55) presented with suspected penile fracture during an 8-year period. One man presented twice. Two of the patients were managed expectantly and the remaining 16 patients underwent 17 immediate surgical explorations. Explorations were performed under general anesthesia, using a circumferential subcoronal incision and degloving of the penile skin. The tunica albuginea of both penile sides as well as the penile urethra were examined for injuries. MAIN OUTCOME MEASURES: Medical records were retrospectively reviewed for etiology, symptoms, signs of physical examination, and information on findings of surgical exploration. Data on erectile function, medical treatment for erectile dysfunction, and penile curvature were obtained during follow-up. RESULTS: In nine of the 17 procedures the tunica albuginea was intact and the only pathological finding was a ruptured dorsal vein. One procedure was negative for both tunical and vascular injury. A tunical tear was detected in the remaining seven procedures. At a mean follow-up of 40 months (range 4-91), five patients required medical treatment for erectile dysfunction, including the two who were managed expectantly, two with a tunical tear, and one with a venous tear. CONCLUSIONS: Dorsal vein tears may mimic penile fracture. Suggestive findings following trauma to the erect penis prompted exploration for suspected tunica albuginea tear. In less than half of the men was the diagnosis of penile fracture established and treated at surgery.

Adult↗

Is computed tomographic scanning necessary in patients with tentorial herniation? Results of immediate surgical exploration without computed tomography in 100 patients.

Computed tomographic (CT) scans are performed on virtually all patients with severe head injury at the time of admission. Because of the time involved in obtaining these studies, the evacuation of significant intracranial mass lesions is delayed. To avoid such delays, the authors performed burr-hole exploration for the diagnosis of intracranial hematomas before CT scans were obtained in 100 consecutive head-injured patients with clinical signs of tentorial herniation or upper brain stem dysfunction upon admission to the emergency room. Patients in whom a hematoma was discovered had a craniotomy for evacuation of the clot; those in whom the exploration was negative had a CT brain scan immediately after operation. Burr-hole exploration revealed extracerebral mass lesions in 56 patients. In 38 patients, the exploration was negative, and postoperative CT scanning showed no significant hematoma. Of 6 patients in whom the CT scan demonstrated extraaxial hematomas requiring surgical evacuation, 4 had subdural hematomas that were missed because the exploration was incomplete; 1 patient had an epidural hematoma and 1 had a subdural hematoma contralateral to a craniotomy on the side of a positive initial burr-hole exploration. Our results indicate that the relatively small subgroup of head-injured patients with early tentorial herniation or upper brain stem compression have a high incidence of immediate extraaxial hematomas and a low incidence of intracerebral hematomas. This is particularly true of patients over 30 years of age and those who suffer low speed trauma, such as falls and vehicle-pedestrian accidents.

Adult↗

Are two hands better than one? assessing information acquired from one- and two-handed haptic exploration of random forms.

15 male undergraduates were presented with 10-sided random forms which they explored visually, or one-handed haptically, or two-handed haptically. Forms were exposed for various durations and subjects were required to draw each form immediately after its removal. The results indicated that 30 sec. of one-handed exploration and 20 and 30 sec. of two-handed exploration produced performance comparable to just 2 sec. of visual exploration. Two-handed exploration was significantly superior to one-handed exploration only at the 20-sec. exposure duration. These results illustrate the disparity in the information-gathering capabilities between the visual and haptic systems.

Form Perception↗

Unilateral versus bilateral neck exploration in parathyroid surgery: an assessment of 55 cases.

We retrospectively evaluated the cases of 55 patients who had undergone surgery for primary hyperparathyroidism at our institution to determine whether their parathyroid glands were abnormal on both sides. Thirty-six of these patients had undergone a bilateral neck exploration, and 19 had had a unilateral investigation. Of the 36 bilaterally explored patients, 30 had a solitary adenoma and no parathyroid pathology on the opposite side, five patients had hyperplastic glands with more than one gland involved, and one patient had two adenomas. In the unilaterally explored group, all 19 patients had a solitary adenoma. There were no failures in the way of persistent hypercalcemia in either group. Based on our findings, we conclude that a unilateral neck exploration should be performed during surgery for primary hyperparathyroidism whenever a large parathyroid adenoma and a normal parathyroid gland are found on the same side. Bilateral exploration should be reserved for patients in whom pathology cannot be found on the initially explored side during surgery and for patients who have obvious parathyroid hyperplasia.

Adenoma↗

On the potential value and limitations of emphasis change and other exploration-enhancing training methods.

Two experiments are presented that examine the efficiency of training methods that force trainees to explore the possible strategy space. Both experiments used a 2-dimensional search task. Experiment 1 studies a method that enforces exploration by preventing repetitions within short sequences. It shows that the effect of this "enhanced exploration" method in the abstract setting is similar to the effect of "emphasis change" training (see D. Gopher, 1993) in high cognitive workload tasks. This finding appeared only in strategic spaces where intuitive exploration converges to a local optimum. Experiment 2 compares the effect of exploration enhancement with the effect of guided instruction. The results of the experiments, which are captured well by a generalization of I. Erev and D. A. Gopher's (1999) model of the conditions for the success of emphasis change training, shed light on the limitations and potential of exploration-enhancing training methods.

Adult↗

Re-exploration for hemorrhage following open heart surgery differentiation on the causes of bleeding and the impact on patient outcomes.

OBJECTIVES: To differentiate surgical bleeding requiring re-exploration from postoperative coagulopathy and determine the differences in patient outcomes. METHODS: This was a retrospective chart review of 2,263 adult patients undergoing elective and emergency open heart procedures encompassing coronary artery bypass, valvular, and a combined procedure to determine the impact of source of bleeding leading to re-exploration. RESULTS: Eighty-two patients (3.6%) required re-exploration. Sixty-six percent had surgical bleeding; the remaining 34% were coagulopathic. Postoperative coagulopathy was associated with preoperative heparin use (37% vs. 19.9% for controls p<0.05). Re-operative procedures combined bypass/ valve (p<0.001) and prolonged cardiopulmonary bypass and aortic cross-clamp times (p<0.05) were more prevalent in the coagulopathy group. Postoperative inotrope use was increased in patients who were re-explored (p<0.001), as were cardiac, pulmonary, renal and abdominal complications (p<0.001), and in all cases those patients with medically related bleeding had worse acute outcomes than the group with surgical causes for re-exploration. The hospital stay was prolonged for both patients with surgical bleeding (23.5 days) and patients with coagulopathy (27.1 days) compared to patients not undergoing re-exploration for bleeding (12.0 days, p<0.001). Survival was 91.3% for patients with surgical bleeding, 87.5% for patients with coagulopathy, and 98.0% for all others (p<0.01). CONCLUSIONS: Severe postoperative hemorrhage is associated with significant morbidity and increased mortality. Postoperative hospital stay, morbidity, and mortality were significantly worse in patients suffering from coagulopathy when compared to those patients with hemorrhage from surgical causes.

Cardiac Surgical Procedures↗

[Surgical treatment of primary hyperparathyroidism: minimally invasive if possible, conventional neck exploration if necessary].

OBJECTIVE: To determine the results of surgical treatment of patients with primary hyperparathyroidism by means of a protocol consisting of preoperative imaging, perioperative parathormone (PTH) measurement, and a minimally invasive approach in the case of a solitary parathyroid adenoma being unequivocally identified and a conventional neck exploration in all other cases. DESIGN: Prospective and descriptive. METHODS: A total of 100 consecutive patients with primary hyperparathyroidism underwent neck imaging (ultrasound, CT) according to a fixed protocol. When a solitary parathyroid adenoma could be unequivocally identified, patients underwent minimal invasive surgery. All other patients underwent a conventional systematic neck exploration. If during the minimally invasive approach the parathyroid adenoma could not be found or the PTH level did not exhibit a decrease of more than 50% perioperatively, the procedure was converted to a conventional neck exploration. A successful operation was defined as a persistent normocalcaemia. RESULTS: In 74 patients preoperative imaging was performed with ultrasound and CT, in 20 patients only ultrasound was used, 4 patients underwent CT in combination with scintigraphy and 2 patients only CT. In 72 of the 100 patients a minimally invasive approach was carried out and for 6 of these the procedure was converted to a conventional neck exploration (in 4 patients the adenoma was not found, in 2 there was an insufficient decrease in PTH level). A primary conventional exploration was carried out in 28 patients. Normocalcaemia was achieved in 98 of the 100 patients. In 2 patients the hypercalcaemic state persisted (in one due to iatrogenic failure, in one due to a mediastinal adenoma). CONCLUSION: The protocol presented had a 98% success rate. Therefore, a conventional neck exploration is no longer the procedure of first choice in the surgical treatment of primary hyperparathyroidism; in two thirds of cases a minimally invasive technique suffices.

Adenoma↗

[Mediastinal exploration by sternotomy in surgery of hyperparathyroidism. 36 cases].

Mediastinal exploration by sternotomy was carried out 36 times in 35 patients with evidence of hyperparathyroidism amongst a group of 1,461 operations for hyperparathyroidism between 1962 and 1987. The exploration was indicated 30 times as re-operation for hyperparathyroidism persistent after one or more negative cervicotomy procedures or recurrent, and 6 times from the outset, (5 in a context of acute hypercalcemia). Exploration was positive 20 times (16 adenomas, 2 hyperplasias, 2 metastases of a parathyroid carcinoma), but negative 16 times (3 diagnostic errors, 6 cervical lesions discovered subsequently, 7 explorations totally negative). The site of mediastinal parathyroid lesions is usually intrathymic (13 cases) but may sometimes (3 cases) be in the middle mediastinum. Pre-operative investigation to identify the site of a possible mediastinal lesion, in re-operation surgery, remains unreliable, the best investigation in this series being thoracic CT scan with 63% true positives. Thallium-Technetium subtraction isotope scan, carried out once with a good result, should now have a place amongst investigations. The principal post-operative complication is hypoparathyroidism which can be prevented by cryopreservation of a fragment of the lesion for possible subsequent reimplantation. Mediastinal exploration is rarely indicated in hyperparathyroid surgery and should be undertaken only after meticulous cervical exploration.

Adenoma↗

The necessity of mandatory exploration of penetrating zone II neck injuries.

To reevaluate the validity of our policy of mandatory surgical exploration of penetrating zone II neck injuries, the charts of 110 patients who underwent surgical exploration for such injuries were reviewed. Fifty-three percent of the patients had normal findings at exploration, whereas 33% had injuries involving vascular structures of the neck and 14% had nonvascular injuries. Injuries were not suspected on clinical grounds preoperatively in 23% of the patients in whom surgical exploration revealed injury. The injuries most likely to escape preoperative diagnosis were isolated venous injuries and isolated pharyngoesophageal injuries. Arteriography yielded false-negative results in two arterial injuries. No deaths and only a 5% incidence of minor complications occurred in the group with no injuries detected at exploration. We conclude that surgical exploration of penetrating zone II neck injuries is safe and appropriate.

Adolescent↗