Force controlled and teleoperated endoscopic grasper for minimally invasive surgery--experimental performance evaluation.

Minimally invasive surgery generates new user interfaces which create visual and haptic distortion when compared to traditional surgery. In order to regain the tactile and kinesthetic information that is lost, a computerized force feedback endoscopic surgical grasper (FREG) was developed with computer control and a haptic user interface. The system uses standard unmodified grasper shafts and tips. The FREG can control grasping forces either by surgeon teleoperation control, or under software control. The FREG performance was evaluated using an automated palpation function (programmed series of compressions) in which the grasper measures mechanical properties of the grasped materials. The material parameters obtained from measurements showed the ability of the FREG to discriminate between different types of normal soft tissues (small bowel, lung, spleen, liver, colon, and stomach) and different kinds of artificial soft tissue replication materials (latex/silicone) for simulation purposes. In addition, subjective tests of ranking stiffness of silicone materials using the FREG teleoperation mode showed significant improvement in the performance compared to the standard endoscopic grasper. Moreover, the FREG performance was closer to the performance of the human hand than the standard endoscopic grasper. The FREG as a tool incorporating the force feedback teleoperation technology may provide the basis for application in telesurgery, clinical endoscopic surgery, surgical training, and research.

Prospective study of surgical resection of duodenal and pancreatic gastrinomas in multiple endocrine neoplasia type 1.

BACKGROUND: The role of surgical resection of gastrinoma in multiple endocrine neoplasia type 1 (MEN 1) is controversial because of low biochemical cure rates, but with adequate duodenal exploration higher cure rates may be possible. METHODS: We have prospectively evaluated this proposal in ten consecutive patients with MEN 1 and Zollinger-Ellison syndrome who underwent surgical exploration for gastrinoma resection including a detailed evaluation of the duodenum by palpation, intraoperative endoscopy with transillumination, and duodenotomy. RESULTS: Duodenal tumors were present in seven patients. Six of seven patients had metastatic deposits in lymph nodes, and two of seven had synchronous pancreatic tumors. Three patients had a single duodenal tumor, one patient had two tumors, and three patients had more than 20 duodenal tumors. Positive gastrin staining by use of immunohistochemistry was seen in all duodenal tumors. None of these seven patients were biochemically cured. Of three patients with negative duodenal explorations, two had single pancreatic tumors removed and one had only lymph node gastrinoma. No patients were biochemically cured. CONCLUSIONS: Not all patients with MEN 1 and Zollinger-Ellison syndrome have duodenal gastrinomas. In the 70% of patients with duodenal tumors, even extensive duodenal exploration with removal of positive lymph nodes does not result in cures because 86% of tumors had metastasized to lymph nodes and 43% of patients had large numbers of tumors.

The hematologic toxicity of interleukin-2 in patients with metastatic melanoma and renal cell carcinoma.

BACKGROUND: High dose interleukin-2 (IL-2) has been found to produce durable antitumor responses in some patients, benefiting most greatly those patients with melanoma and renal cell carcinoma. In this paper, the hematologic toxicity and changes resulting from high dose IL-2 alone administered by intravenous bolus are discussed. METHODS: One hundred ninety-nine consecutive patients treated with high dose IL-2 alone from January 1, 1988 to December 31, 1992 were included in this study. All patients had a diagnosis of metastatic melanoma or metastatic renal cell carcinoma and were treated at the National Cancer Institute (Bethesda, MD). RESULTS: Anemia, requiring erythrocyte transfusions, occurred in 14% of all treatment courses, with a median of two units of erythrocytes transfused. Severe leukopenia ( < 1,000 leukocytes/mm3) was rare (1.5% of all patients) and was not associated with any infectious complications. Severe thrombocytopenia ( < 30,000 platelets/mm3) occurred in 2.2% of all treatment cycles, with two patients experiencing a grade 3 hemorrhage, defined as gross blood loss, and one patient experiencing a grade 4 hemorrhage, defined as a debilitating blood loss. Defects in the coagulation pathway were common: abnormal partial thromboplastin time and prothrombin time values occurred in 64% and 25% of the treatment cycles, respectively. In addition, a mean clearance of 93% of lymphocytes from the peripheral blood was observed within 24 hours after initiating IL-2 therapy. This was followed by rebound lymphocytosis to a mean of 198% of baseline on posttreatment Day 4. There were no treatment-related deaths. CONCLUSIONS: During IL-2 therapy, adverse sequelae of anemia, thrombocytopenia, coagulopathy, and leukopenia were usually mild, transient and rarely limited therapy. A profound decrease in lymphocytes in the peripheral circulation occurred within 24 hours after initiating therapy, with a rebound occurring after stopping IL-2. No specific hematologic parameter was associated significantly with a patient's increased probability of responding to therapy.

Renal dysfunction associated with the administration of high-dose interleukin-2 in 199 consecutive patients with metastatic melanoma or renal carcinoma.

PURPOSE: To describe the incidence and management of renal dysfunction associated with the use of high-dose interleukin-2 (IL-2) (as is currently approved) in the treatment of cancer patients. PATIENTS AND METHODS: One hundred ninety-nine consecutive patients with metastatic renal carcinoma or melanoma were treated with intravenous bolus infusions of IL-2 alone (720,000 IU/kg) every 8 hours. RESULTS: Patients received 310 courses (589 cycles) of therapy and most experienced oliguria, hypotension, and weight gain; 13% of cycles were discontinued due to increased serum creatinine levels. Creatinine values (mean pretherapy, 1.2 mg/dL) increased during therapy and peaked (mean, 2.7 mg/dL) approximately 1 day after discontinuation of the second cycle of IL-2. Off therapy, toxicities reversed promptly and creatinine values returned to baseline. Higher peak creatinine values occurred in patients with renal carcinoma (v melanoma), older patients, males (v females), and those who had undergone prior nephrectomy. These same patient subsets received fewer doses of IL-2, but clinical responses were not associated with creatinine values or number of IL-2 doses administered. Urinalyses showed the appearance of protein, bilirubin, RBCs, WBCs, and granular casts during therapy, which cleared completely on follow-up evaluation. CONCLUSION: High-dose IL-2 can be safely administered to cancer patients. The associated renal dysfunction is transient and without evidence of intrinsic long-term renal damage. Practical guidelines for patient management have been identified.

Use of preoperative fine-needle aspiration in patients undergoing reoperation for primary hyperparathyroidism.

BACKGROUND: Neck reexploration for primary hyperparathyroidism has a lower success rate and greater morbidity than initial exploration because of scarring and distortion of tissue planes and the possibility of a parathyroid neoplasm located in an ectopic or unusual position. Although the use of standard noninvasive imaging studies for reoperative parathyroid surgical procedure is well accepted, the use of invasive studies to localize parathyroid neoplasms, particularly percutaneous aspiration of potential lesions, is controversial. In this report we analyze the results and morbidity in patients undergoing fine-needle aspiration before neck reexploration. METHODS: From 1982 to 1993, 255 patients underwent reexploration for persistent or recurrent hyperparathyroidism at the National Institutes of Health. Of these 255 patients 42 underwent 44 preoperative fine-needle aspirations by ultrasonography or computed tomography guidance in an attempt to localize a parathyroid neoplasm. The aspirated contents were then analyzed for parathyroid hormone content. RESULTS: Of the 44 aspirations 26 (59%) were true positives with no false positives. Of 18 negative fine-needle aspirations, 11 (25%) were false negatives, and seven (16%) were true negatives. The specificity and sensitivity of percutaneous fine-needle aspiration were 100% and 70%, respectively. CONCLUSIONS: Percutaneous fine-needle aspiration for parathyroid hormone is a safe, well-tolerated technique that is highly specific and allows a directed surgical resection avoiding further invasive workup when the aspirate is positive.

Cardiopulmonary toxicity of treatment with high dose interleukin-2 in 199 consecutive patients with metastatic melanoma or renal cell carcinoma.

BACKGROUND: Administration of recombinant interleukin-2 (rIL-2) can mediate tumor regression in patients with metastatic melanoma and renal cell carcinoma. In response to recent FDA approval of high dose rIL-2 for use in renal cell carcinoma, the authors recent experience with the cardiopulmonary toxicity associated with high dose IL-2 therapy is reviewed. METHODS: The treatment courses of all patients receiving high dose intravenous bolus rIL-2 from January, 1988, until December, 1992, were evaluated for cardiopulmonary toxicity. RESULTS: One hundred ninety-nine patients received 310 courses of treatment. There were no treatment-related deaths. Respiratory distress occurred in 3.2% of the courses, requiring intubation in one patient. Three obtunded patients were endotracheally intubated for airway control. Arrhythmias occurred in 6% of the courses (18 patients) with hypotension developing in two of the 199 patients as a result. Eleven of these patients were retreated and recurrent atrial fibrillation developed in two. One episode of significant ventricular tachycardia was noted. Hypotension occurred in 53% of courses; no patients developed hypotension unresponsive to vasopressors. There were no myocardial infarctions; however, 2.5% of patients experienced elevated creatine phosphokinase levels associated with elevated MB isoenzymes attributed to cardiac toxicity. Only one of these patients developed symptoms. Response rates of 19.6% and 15.7% were noted in patients with renal cell carcinoma and melanoma, respectively. Hypotension requiring vasopressors was associated with a significantly improved rate of response in patients with melanoma compared with patients not requiring vasopressors (23.2% vs. 6.5%, P2 = 0.037). CONCLUSIONS: Although high dose intravenous rIL-2 therapy can be associated with cardiopulmonary toxicity, toxic side effects generally are not severe and are rapidly reversible.