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Thomas Frede

Publications and source records attributed to Thomas Frede.

21 records · Page 2Linked to original sources
PubMed2003

Oncological safety of laparoscopic surgery for urological malignancy: experience with more than 1,000 operations.

PURPOSE: Although laparoscopy is being increasingly used to treat urological malignancies, there is still concern regarding the induction of local recurrence and port site metastasis. To our knowledge no major clinical study with long-term followup has been presented in the field of urological laparoscopy. We assessed the oncological safety of laparoscopy with emphasis on incidence of local recurrence and port site metastasis, analyzing the risk factors for such events based on a 10-year experience. MATERIALS AND METHODS: From June 1992 to May 2002 we performed 1,098 laparoscopic procedures for urological malignancies, including 450 radical prostatectomies, 478 pelvic and 80 retroperitoneal lymph node dissections, 45 radical nephrectomies, 22 radical nephroureterectomies, 12 partial nephrectomies and 11 adrenalectomies. In 418 cases of laparoscopic radical prostatectomy pelvic lymphadenectomy was done simultaneously. Of the procedures 917 were performed transperitoneally, including 181 via retroperitoneal or extraperitoneal access. A total of 567 procedures were performed in case of histologically proven cancer, whereas 531 represented only staging operations. RESULTS: Median followup was 58 months (range 4 to 127). Eight local recurrences were observed (0.73% overall, 1.41% of histologically proven cases). There were recurrences after nephroureterectomy for transitional cell carcinoma of the ureter in 1 patient, after radical nephrectomy for renal cell carcinoma in 1, growing teratoma after retroperitoneal lymph node dissection in 2, local recurrence of prostate cancer in 3 and after removal of an adrenal metastasis of melanoma in 1. Two port site metastases (0.18% overall, 0.35% of histologically proved cases) occurred, including metastasis of small cell lung carcinoma after adrenalectomy and a residual mass following 2 cycles of chemotherapy after retroperitoneal lymph node dissection. CONCLUSIONS: According to our experience the incidence of local recurrence and the risk of port site metastases is low and seems to be mainly related to the aggressiveness of the tumor and immunosuppression status of the patient, respectively rather than to technical aspects of the laparoscopic approach.

Adrenalectomy↗
PubMedDate not supplied

Robotics, telesurgery and telementoring--their position in modern urological laparoscopy.

OBJECTIVES: Laparoscopic surgery in general is handicapped by the reduction of the range of motion from six to four degrees of freedom. This has a major impact on technically difficult procedures such as laparoscopic radical prostatectomy. Solutions for this problems include the understanding of the geometry of laparoscopy with sophisticated training programs, but lie also in newly developed surgical robots, computer simulators and telementoring. This article evaluates the value of these alternatives based on own experiences and an analysis of the current literature. METHODS: Own experiences with robot-assisted surgery include 406 laparoscopic radical prostatectomies using a voice-controlled camera-arm (AESOP) as well as 6 telesurgical interventions with the Da Vinci-system. Additionally, substantial experimental studies have been performed focussing on the geometry of laparoscopy and new training concepts such as perfused pelvitrainers and computer simulation. Moreover, the current literature of the last 10 years on telesurgery and telementoring has been reviewed. RESULTS: The geometry of laparoscopy includes the angles between the instruments which have to be in a range of 25 degrees to 45 degrees; the angles between the instrument and the working plane that should not exceed 55 degrees; and the angle between the shaft of the needle holder and the needle which has to be adapted according to the anatomical situation in range of 90 to 110 degrees. 3-D-systems did not yet proved to be effective due to handling problems such as shutter glasses, video-helmets or reduced brightness. At the moment, there are only two robotic surgical systems (ZEUS, Da Vinci) in clinical use for telesurgery, of which only the Da Vinci provides stereovision and all six degrees of freedom (DOF). In the meantime, more than 200 laparoscopic radical prostatectomies have been performed with this system. Until now, however, there was no evidence of any advantages over the conventional laparoscopic approach. The ZEUS in combination with the telecommunication system SOKRATES is the only device enabling to realize telemanipulation and telementoring over long distances (i.e. transatlantic). CONCLUSION: Robotic surgery represents a turning point of surgical research. However, broad use of robotic systems is limited mainly because of the high investment and running costs. Whereas there will be a clear role of audio-visual telementoring in future training concepts, the need of telemanipulation/telesurgery has not yet been clarified. New technological concepts promote the development of hand-held mechanical manipulators (i.e. 6-DOF-needle-holder) used in combination with mono-tasking computerized robots (i.e. AESOP) resulting in a significant cost reduction.

Computer Simulation↗