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PubMed1994

Effects of chronic imipramine on exploration, locomotion, and food/water intake in rats.

Three groups of rats were subjected to 15 daily injections of imipramine (10 or 20 mg/kg) or vehicle control injections, respectively. During the treatment period, both imipramine groups failed to grow while the control group gained weight normally. Both dosages of imipramine suppressed food intake significantly, while water intake was only reduced by 20 mg/kg of imipramine and only during the first 5 days of treatment. Twenty-four hours after the last imipramine injection, the animals were subjected to a test battery designed to demonstrate potential changes in locomotion and/or exploration. While locomotion appeared unaffected by both dosages of imipramine, the group receiving 20 mg/kg of imipramine demonstrated a significantly reduced exploration. The exploration of the group receiving imipramine in the concentration of 10 mg/kg was only marginally changed. The temporal pattern of exploration of the animals receiving 20 mg/kg of imipramine revealed that chronic imipramine treatment was associated with an initial "hyperexploration" followed by an "overhabituation," resulting in an overall reduction of exploration during a 15-min period.

Animals↗

PubMed2005

Positron emission tomography with F-18-fluorodeoxyglucose in a combined staging strategy of esophageal cancer prevents unnecessary surgical explorations.

Distant metastases or local invasion are frequently found during the explorative phase of surgery for esophageal cancer. This study was performed to determine the rate of patients with incurable disease encountered during exploration and to examine the impact of preoperative staging, including positron emission tomography (PET), on the number of unnecessary explorations. The records of 203 patients with esophageal cancer who were eligible for curative resection were retrospectively reviewed. The surgical reports were analyzed to obtain the reasons for abandoning resection. Furthermore, the different staging modalities according to the related time interval were reviewed for each patient to analyze the influence of them on the number of explorations. After exploratory surgery, resection was abandoned in 78 of the 203 patients (38%) because of distant metastases (n=59; 29%), metastatic spread and local irresectability (n=5; 2%), and local irresectability (n=14; 7%). In a logistic regression model with all preoperative staging modalities and the year of examination as independent variables, F-18-fluorodeoxyglucose (FDG)-PET) was the only modality that predicts intended curative resection in these patients (P<0.001). In patients with esophageal cancer who are suitable for potentially curative surgery, resection was abandoned mainly because of distant metastases encountered during exploration. The addition of FDG-PET may have reduced the rate of unnecessary surgery in this group of patients.

Adenocarcinoma↗

PubMed2006

Management of cervical stab wounds in low volume trauma centres: systematic physical examination and low threshold for adjunctive studies, or surgical exploration.

INTRODUCTION: In Nordic countries penetrating neck injuries (PNIs) are infrequent and management has traditionally been guided by surgeons' preferences. Some form of selective non-operative approach is currently practised in most urban trauma centres. OBJECTIVE: To examine demographic features and treatment outcome of non-ballistic penetrating neck injuries in southern Finland and provide management guidelines for centres with low volume of penetrating neck trauma. MATERIALS AND METHODS: Retrospective analysis of 85 platysma penetrating neck injuries in two southern Finland hospitals (Helsinki University Central Hospital, HUCH and Tampere University Hospital, TaUH) was carried out using the ICD-10 based hospital databases to identify PNI-patients. RESULTS: The incidence of admitted patients with penetrating neck injuries was 1.3/100000/year. Fifty-two (61%) injuries were caused by random acts of violence, 28 (38%) were self-inflicted and 5 (6%) were accidents. Of all 85 patients, 52 (61%) underwent operative exploration with a negative exploration rate of 65%. Hard signs for vascular or aerodigestive trauma were present in 23 (27%) patients and all of these were operated with a negative exploration rate of 30%. Two patients had no hard signs on physical examination but were operatively explored and significant injuries were found in both patients. The hospital mortality rate was 0% and the overall complication rate for operated patients was 7.7%. CONCLUSIONS: Trauma centres managing PNIs infrequently should have an individually tailored management protocol for penetrating neck injury patients. If mandatory exploration is not practised, a systematic physical examination should be the mainstay of diagnostic work up but the threshold for adjunctive studies should be low. Although not evident by the current data, protocol-based management could be useful in decreasing treatment variation and enhancing residency training.

Adult↗

PubMed2006

Exploration in outbred mice covaries with general learning abilities irrespective of stress reactivity, emotionality, and physical attributes.

Across multiple learning tasks (that place different sensory, motor, and information processing demands on the animals), we have found that the performance of mice is commonly regulated by a single factor ("general learning") that accounts for 30-40% of the variance across individuals and tasks. Furthermore, individuals' general learning abilities were highly correlated with their propensity to engage in exploration in an open field, a behavior that is potentially stress-inducing. This relationship between exploration in the open field and general learning abilities suggests the possibility that variations in stress sensitivity/responsivity or related emotional responses might directly influence individuals' general learning abilities. Here, the relationship of sensory/motor skills and stress sensitivity/emotionality to animals' general learning abilities were assessed. Outbred (CD-1) mice were tested in a battery of six learning tasks as well as 21 tests of exploratory behavior, sensory/motor function and fitness, emotionality, and stress reactivity. The performances of individual mice were correlated across six learning tasks, and the performance measures of all learning tasks loaded heavily on a single factor (principal component analysis), accounting for 32% of the variability between animals and tasks. Open field exploration and seven additional exploratory behaviors (including those exhibited in an elevated plus maze) also loaded heavily on this same factor, although general activity, sensory/motor responses, physical characteristics, and direct measures of fear did not. In a separate experiment, serum corticosterone levels of mice were elevated in response to a mild environmental stressor (confinement on an elevated platform). Stress-induced corticosterone levels were correlated with behavioral fear responses, but were unsystematically related to individuals' propensity for exploration. In total, these results suggest that although general learning abilities are strongly related to individuals' propensity for exploration, this relationship is not attributable to variations in sensory/motor function or the individuals' physiological or behavioral sensitivity to conditions that promote stress or fear.

Animals↗

PubMed2004

Exploration and risk assessment: a comparative study of male house mice (Mus musculus musculus) and two laboratory strains.

The ability to gather information and assess risks in novel environments is crucial for survival and fitness in the wild. Our aim was to characterise behavioural strategies of exploration and risk assessment in novel environments and to investigate in what respects wild house mice differ from domesticated mice. A total of 39 adult male mice from three genetic backgrounds (Wild, BALB/c, and C57BL/6) were tested in three behavioural tests, the concentric square field (CSF), a modified open field (OF), and a conventional elevated plus maze (EPM). In addition to spatial measures, behavioural measures of exploration and risk assessment were registered. The parameters were categorised according to their relevance to activity, exploration, approach-avoidance, and use of open areas/shelter. Wild mice had lower activity and a higher avoidance of open areas than the laboratory strains. No differences were found in exploratory motivation. The BALB/c mice avoided risk areas and showed high risk assessment (SAP), whereas C57BL/6 mice were more explorative and risk taking and showed little risk assessment. Wild mice seemed to have a different behavioural strategy of risk assessment in being more cautious before entering a potentially dangerous zone but explored all zones after assessed as nonrisky. A principal component analysis (PCA) of the animals' behaviour in the CSF arena supported these findings by clearly separating the three strains on the basis of their behavioural performances. It is concluded that there are obvious differences in behavioural strategies related to risk assessment and risk taking among wild mice versus domesticated house mice and also among laboratory strains. The relationship between the animal's risk concern and adaptability is discussed and should be a matter of importance considering animal welfare as well as the experimental aim and protocol.

Adaptation, Psychological↗

PubMed1990

Initial failure of surgical exploration in patients with primary hyperparathyroidism.

To determine the causes of failures of cervical exploration for primary hyperparathyroidism, we reviewed 892 patients operated on by one surgeon from 1953 to 1990. Twenty-seven patients (3%) remained hypercalcemic or developed hypercalcemia within 6 months of surgery. Of these, five patients had one adenoma removed initially; at reoperation, three patients had a second adenoma that was successfully removed, whereas the other two patients had hyperplasia and required subtotal parathyroidectomies. No enlarged parathyroid glands were identified in 22 patients. Eventually, six patients became normocalcemic spontaneously, seven patients underwent re-exploration with a successful outcome in all but one case, two patients had ectopic hyperparathyroidism associated with carcinoma elsewhere, and seven patients refused reoperation and remain hypercalcemic. The failure rate of surgical exploration for primary hyperparathyroidism can be reduced by systematically exploring all four parathyroid glands. All abnormal parathyroids should be removed with histologic verification. When no abnormal glands are found, localization studies should be performed before re-exploration.

Adenoma↗

PubMed1976

Transient obstruction of the common bile duct following its exploration.

Failure of the contrast medium to enter the duodenum during the operative cholangiography following the common bile duct exploration and instrumentation may be caused by transient obstruction of the common bile duct. It is attributed to spasm and oedema of the sphincter choledochus of Boyden and not of the sphincter of Oddi. The knowledge of the possibility of the pseudo-obstruction of the common bile duct following its exploration may save the surgeon from unnecessary re-exploration and performing sphincterotomy or choledochoduodenostomy. The exploration is unnecessary if, during the common duct exploration, the dilators and the catheter passes easily into the duodenum and on the cholangiogram the obstructed area is smooth and there is no filling defect. A normal cholangiogram performed 8-10 days following the operation proves that the obstruction was transient and not caused by calculus stricture or tumour.

Aged↗

PubMed2000

Testicular damage after surgical groin exploration for elective herniorrhaphy.

BACKGROUND/PURPOSE: Controversy exists whether to explore the contralateral groin in boys during unilateral herniorrhaphy. Proponents claim there is minimal risk of injury to the cord structures and developing testicle with contralateral exploration. However, findings have shown testicular atrophy occurred in 1% to 2% of patients after herniorrhaphy, and vasal damage is possible after routine manipulation of the spermatic cord. This study investigated the effect of routine surgical exploration of the prepubertal groin on testicular development and future fertility. METHODS: Twenty-four prepubertal Wistar rats were divided equally into 2 groups. Group 1 (sham) rats underwent unilateral inguinoscrotal incision only. Group 2 (experimental) rats underwent unilateral inguinoscrotal exploration with manipulation of the cord structures as in human inguinal exploration. At maturation, the fertility and fecundity of the males were assessed. After mating, testes were examined for mass, volume, mean seminiferous tubule diameter (MSTD), and mean testicular biopsy score (MTBS). The vasa were examined for histological injury and vasal diameter. Statistical comparisons were made by paired t test and Mann-Whitney rank sum test. RESULTS: There was a difference between the volumes of the testes when comparing the operative and nonoperative side of the 2 groups (experimental, deltavol = -0.063+/-0.123; sham, deltavol = +0.067+/-0.137; P = .029). There also was a trend toward a smaller testicular mass when comparing the two sides (experimental, deltamass = -0.045+/-0.101; sham, Amass = +0.048+/-0.123; P = .057) but did not reach significance. The MSTD and MTBS were similar between the ipsilateral and contralateral testes in both groups. Likewise, the MSTD and MTBS were similar when comparing the 2 groups. All male rats in both groups were fertile. The number of offspring produced and the number of female rats impregnated were similar between the 2 groups. There was no histological evidence of vasal injury in any of the experimental spermatic cords. The vasal diameters were similar between the 2 groups. CONCLUSION: Surgical manipulation of the prepubertal spermatic cord imparts a small, but statistically significant morphological change in testicular size without a deleterious effect on testicular development, fertility, or fecundity.

Animals↗

PubMed2002

Impaired metabolic capacity in the perirhinal and posterior parietal cortex lead to dissociation between attentional, motivational and spatial components of exploration in the Naples High-Excitability rat.

This study aimed at investigating the neural substrates of spatial and non-spatial Behavioural components of exploration to novelty by a neurogenetic approach. Thus, functional imaging and Behavioural analysis were carried out in the Naples High-Excitability (NHE) rats, a model of hyperactivity and attention-deficit. Quantitative cytochrome oxidase (C.O.) histochemistry was used to measure the basal metabolic capacity of different forebrain structures. In parallel experiments, exploration in an 8-arm radial maze (Olton-maze) with extra-maze cues was used to measure attentional, motivational and spatial components of Behaviour after feeding rats' ad-libitum or at a reduced diet. Functional imaging analysis: brains from naive rats were stained for quantitative C.O. histochemistry along with standards. NHE rats showed lower C.O. activity in perirhinal and posterior-parietal cortex (all layers) and cortical amygdala, and greater activity in entorhinal cortex (superficial layers). The outer granular cell layer of the dentate gyrus had greater activity in NHE. Behavioural analysis: at low and high motivational level, maze exploration was reinforced during shaping throughout and then only a single arm. The Behaviour was monitored by a CCD camera and videotaped. (i) There was no line difference in working memory during non reinforced maze exploration, independent of the motivational level; (ii) during shaping with all baited arms, there was no line difference in working memory, but NHE rats showed a very low or lower food consumption at low and high motivational level, respectively; (iii) rats showed a higher working memory in finding the single baited arm at high motivational level; (iv) NHE rats paid little attention towards reinforcement upon visiting the baited arm only at low motivational level. Thus, Behavioural and functional neuroimaging analysis suggests the neural substrates of spatial and non-spatial components of exploration to be underlined by different network operations in the neocortical and limbic cortices in the NHE rat lines. Therefore, they appear as an useful tool to the understanding of Attention-Deficit Hyperactivity Disorder (ADHD) in children.

Animals↗

PubMed2003

Bidirectional modulation of long-term potentiation by novelty-exploration in rat dentate gyrus.

Previous studies have shown that exploration of a novel environment reverses hippocampal long-term potentiation (LTP). Here we demonstrate a bidirectional modulation of LTP measured in the dentate gyrus of freely moving rats by means of novelty exploration. A transient form of LTP lasting about 6 h was induced in perforant path-granular cell-synapses by a weak tetanization protocol (three bursts of 15 pulses at f=200 Hz). LTP was reversed when non-restricted exploration of a novel environment started 2 min after LTP induction. In contrast, using the same interval and limiting the exploration duration to 1 min led to LTP-prolongation. Furthermore, LTP-reinforcement was also obtained when a not-restricted exploration started within 2 min before tetanization. The observed interplay of LTP-impairing and -enhancing factors may be relevant for the modulation of memory formation by novelty.

Animals↗

PubMed1996

Is inguinal exploration for the impalpable testis an outdated operation?

OBJECTIVE: To evaluate the reliability of open inguinal exploration for the investigation of the impalpable testis by reviewing laparoscopic findings after previous negative inguinal exploration. PATIENTS AND METHODS: Laparoscopy was performed in 18 boys (with a total of 22 impalpable testes) in whom previous inguinal exploration in their referring hospitals had yielded negative or inconclusive findings. Subsequent management of the impalpable testes was based on laparoscopic findings. RESULTS: Despite previous negative surgical findings at inguinal exploration, laparoscopy revealed that 13 of the 22 impalpable testes (59%) were present, 12 within the abdomen and one in the inguinal canal. Absence of the remaining nine testes was positively confirmed by visualizing confluent blind ending vas and vessels. CONCLUSION: Inguinal exploration is an unreliable method of investigating the impalpable testis, with an unacceptably high incidence of false-negative or inconclusive findings. Laparoscopy should be undertaken as the initial diagnostic manoeuvre of choice.

Adolescent↗

PubMed2000

Sestamibi scan-directed unilateral neck exploration for primary hyperparathyroidism due to a solitary adenoma.

AIM: To evaluate the accuracy of Tc-99m sestamibi scintography in pre-operative localization of a single parathyroid adenoma and to determine if neck exploration can be limited to the side of the adenoma. METHODS: Over a period of 4 years, 30 patients with primary hyperparathyroid disease underwent surgical treatment in the form of unilateral neck exploration after localization by Tc-99m sestamibi scintigraphy. The scan findings were interpreted by one radiologist with a special interest in parathyroid imaging and the operative findings were correlated with scan findings. RESULTS: Tc-99 sestamibi scan localized a single parathyroid adenoma in 29 patients. There was doubtful uptake of isotope in one patient. Unilateral cervical exploration confirmed isotope scan findings in 29 patients with a positive scan, and these were subsequently proven by histology. In the patient with doubtful sestamibi scan, bilateral neck exploration was undertaken and three enlarged glands were excised. All the three glands were reported to be abnormal, consistent with either adenomas or hyperplasia. All the patients were normocalcaemic after 6 months follow-up. CONCLUSIONS: Our results demonstrate that Tc-99m sestamibi scintigraphy is highly accurate in pre-operative localization of a single parathyroid adenoma when performed by an experienced radiologist. Unilateral cervical exploration, as directed by a positive Tc-99m sestamibi scintigram, seems to be a logical approach for the patients with primary hyperparathyroid disease due to solitary adenoma.

Adenoma↗

PubMed1999

[Ultrasound investigation of cervical lymph node metastases: conception and results of a histopathological exploration].

BACKGROUND: Ultrasound (US) is one of the most important methods for detection of cervical lymph node metastases in malignancies of the head and neck. In our study, the specificity of ultrasound was explored by a special, histopathological exploration considering the anatomical regions of the neck. METHODS: Thirty-eight patients were studied (5 female, 33 male, age: 38-86 years) with different histology and incidence of metastatic spread of head and neck cancers. Forty-six neck dissections were performed (30 radical and 16 selective). Histological exploration was performed after pinning the neck soft tissue with needles to anatomical live drawings of the lymph node regions, a modification of the Medina procedure. This procedure allowed a correct topographical assignment of lymph node metastases and comparison of preoperative sonographical findings with histopathological results. RESULTS: We isolated 1333 lymph nodes, 137 of them infiltrated by metastases. These lymph node metastases were found in 28 of 46 neck dissections. The number of lymph nodes in radical neck dissections ranged from 21 to 60 (mean: 36), in selective neck dissection from 1 to 43 (mean: 16). Sensitivity, specificity, and accuracy of ultrasound reached 96%, 69%, and 78%, respectively. Seventy-two lymph node metastases (52%) of 12 neck dissections could not be evaluated by ultrasound. CONCLUSIONS: Our results confirm the reliability of ultrasound regarding sensitivity, specificity and accuracy of US-detectable cervical lymph nodes as reported in world literature. However, we were able to demonstrate in special histopathological explorations, that ultrasound did not detect more than 50% of present lymph node metastases in our series. We consider it essential to perform histopathological explorations of the soft tissue of the neck as described in our study to evaluate the efficacy and reliability of US, CT, and MRI in detecting lymph node metastases of head and neck malignancies.

Adult↗

PubMed1999

Unilateral neck exploration under local anesthesia: the approach of choice for asymptomatic primary hyperparathyroidism.

BACKGROUND: Conventional parathyroidectomy involves a bilateral neck exploration with the patient under general anesthesia with a thorough search for all parathyroid tissue. The purpose of this study was to assess the efficacy and safety of unilateral neck exploration under local anesthesia in patients with asymptomatic primary hyperparathyroidism (first-degree hyperparathyroidism). METHODS: Of 679 patients who underwent parathyroidectomy for first-degree hyperparathyroidism from July 1989 to June 1997, 230 asymptomatic patients underwent unilateral neck exploration under local anesthesia. Selection criteria for this approach included the successful identification of a solitary parathyroid adenoma on preoperative imaging, no thyroid disease, and no family history of multiple endocrine neoplasia. Intact parathyroid hormone levels were monitored during the operation. RESULTS: Total serum calcium levels were normal in 220 patients (96%) 3 to 6 months after surgery. Ten patients (4%) experienced persistent hypercalcemia, 8 of whom had multiple gland disease and 2 of whom had false-positive imaging. Two of these patients underwent bilateral neck exploration under general anesthesia and were cured, although 8 patients remained asymptomatic and were followed up non-operatively. The mean operating time was 30 minutes (range, 12-65 minutes). There were two complications (0.87%) including one wound hematoma and one transient recurrent laryngeal nerve palsy. CONCLUSIONS: Unilateral neck exploration under local anesthesia is an efficacious and safe approach to the treatment of first-degree hyperparathyroidism and should be considered in all patients with asymptomatic disease.

Adenoma↗

PubMed2001

Laparoscopic common bile duct exploration.

BACKGROUND: Laparoscopic common bile duct (CBD) exploration is gaining favor in the treatment of patients with gallstones and CBD stones. Our aim is to report our results with this procedure, focusing on the technical aspects. PATIENTS AND METHODS: All patients with proven CBD stones undergo laparoscopic transcystic CBD exploration, preferably, or a choledochotomy if the former is not feasible. According to CBD stone load and diameter, a biliary drainage tube is positioned for postoperative biliary decompression. RESULTS: Among 284 patients who underwent laparoscopic CBD exploration, 4 (1.4%) were converted to open surgery. Transcystic CBD exploration was feasible in 163 cases (58.2%), but a choledochotomy was required in 117 (41.8%). Biliary drains were positioned in 204 patients (72.8%). Minor complications included hyperamylasemia (11; 3.9%) and minor subhepatic bile collection (7; 2.5%). Major complications were bile leakage (5; 1.8%), hemoperitoneum from cystic artery bleeding (2; 0.7%), subhepatic abscess (2; 0.7%), acute pancreatitis (1; 0.3%), and jejunal perforation (1; 0.3%). Retained CBD stones in 15 patients (5.3%) were removed through the biliary drainage sinus tract (8) or after endoscopy and sphincterotomy (6). In one patient, a small stone passed spontaneously (overall success rate 94.6%). Death from a cardiovascular complication was observed in one elderly high-risk patient (0.3%). Recurrent ductal stones in 5 patients (1.8%) were treated with ERCP and endoscopic sphincterotomy. One patient with re-recurrent ductal stones underwent hepaticojejunostomy. CONCLUSIONS: Laparoscopic CBD exploration during LC in unselected patients solves two problems during the same anesthesia with high success rates (94.6%), low minor (6.4%) and major (3.8%) morbidity rates, and a low mortality rate (0.3%). Standardization of the technique is mandatory to achieve high success rates.

Adolescent↗

PubMed1993

Complete abdominal exploration is unnecessary during the treatment of cholelithiasis.

The development of laparoscopic and non-operative methods for the management of cholelithiasis has been based on the premise that abdominal exploration during cholecystectomy is unnecessary. In the current study, 305 patients undergoing complete abdominal exploration during routine cholecystectomy were evaluated to assess the incidence and significance of intraabdominal pathology found at the time of exploration. While 41 patients (13.4%) were found to have additional diagnosis at the time of exploration, the majority of these were either minor in nature or would easily have been recognized utilizing laparoscopic techniques. Only one patient would have had significant intraabdominal pathology missed by laparoscopic techniques. It can be concluded that abdominal exploration at the time of treatment of cholelithiasis is unnecessary and that laparoscopic cholecystectomy will not compromise patient care in this regard.

Cholecystectomy, Laparoscopic↗

PubMed1978

Microsurgical anatomy of the orbital apex and principles of transcranial orbital exploration.

Although many problems may present with unilateral proptosis, a careful clinical investigation can narrow the differential diagnosis to those problems which can be treated best by the neurosurgeon. The primary indication for transcranial exploration is when the pathological process is found to involve both the orbit and the cranial cavity as in all cases of optic nerve glioma, orbital meningioma, encephalocele, and some mucoceles, hemangiomas, aneurysmal bone cysts, and ossifying fibromas. Transcranial exploration may also be indicated for some tumors which crowd the orbital apex, such as, neurofibromas and osteomas; tumors in this location can be more widely exposed and safely dealt with by this route. A prime objective in these cases, however, must be preservation of function with a good cosmetic result. It is of equal importance to be aware that many conditions producing exophthalmos can be cured by direct orbital exploration, radiotherapy, or medical management. Malignant orbital tumors should never be exposed to the cranial cavity by transcranial exploration, whereas, radical exenteration may be curative in some carefully studied cases. Accuracy in clinical diagnosis and the proper selection of treatment modality for conditions in the orbit requires a clear understanding of this regional anatomy. I hope that this brief review of the pertinent microsurgical anatomy of the orbital apical region has helped to substantiate a strong neurosurgical claim to all primary optic nerve tumors; and, incidentally, I hope it provides an explanation for why I sent so many other patients back to Dr. Algernon Reese with the recommendation that transcranial surgery did not seem indicated. The success of this attitude may be attested to by the fact that we performed no unnecessary craniotomies nor did we pass by problems which would have best been treated by transcranial orbital exploration.

Cranial Nerve Neoplasms↗

PubMed1980

The value of choledochoscopy in exploration of the common bile duct.

Direct visualization of the biliary tree using choledochoscopy has been recommended as a technique to improve the accuracy of common duct exploration. In several series the incidence of retained biliary calculi has been dramatically reduced using choledochoscopy, and some authors have reported the findings of other unsuspected benign and malignant lesions as well. During an eight-year period 288 patients underwent exploration of the common bile duct specifically for calculous disease. Operative rigid choledochoscopy was performed in 140 patients in this group, with 79 found to have choledocholithiasis; seven retained stones occurred in this group for an incidence of 8.9%. Routine common duct exploration in the other 148 patients revealed 67 to have choledocholithiasis; six retained stones occurred in this group for an incidence of 9.0%. Though there was no difference in the incidence of retained stones with or without choledochoscopy, 20 patients were found to have stones missed during routine exploration once the rigid choledochoscope was inserted. In addition to the obvious value of the choledochoscope in identifying and removing common duct stones, it was also found to be an aid in removing stones in the intra-hepatic ducts and in clarifying atypical anatomy. Other causes of biliary obstruction such as a liver fluke, benign polyp, benign strictures, and ductal carcinomas were identified by use of biopsy forceps inserted through the choledochoscope. It is recommended that routine choledochoscopy be performed during common duct explorations and that surgical training programs insure that residents learn the technique of operative choledochoscopy.

Cholestasis, Extrahepatic↗