The purpose was to evaluate differences in dynamic changes of the lung aeration (air-tissue ratio) between augmented modes of ventilation (AMV) and controlled mechanical ventilation (CMV) in normal subjects. 4 volunteers, ventilated with the different respirator protocols via face mask, were scanned using the EBCT in the 50 ms mode. A software analyzed the respirator's digitized pressure and volume signals of two subsequent ventilation phases. Using these values it was possible to calculate the onset of inspiration or expiration of the next respiratory phase. The calculated starting point was then used to trigger the EBCT. The dynamic changes of air- tissue ratios were evaluated in three separate regions: a ventral, an intermediate and a dorsal area. AMV results in increase of air-tissue ratio in the dorsal lung area due to the active contraction of the diaphragm, whereas CMV results in a more pronounced increase in air-tissue ratio of the ventral lung area. This study gives further insight into the dynamic changes of the lung's biomechanics by comparing augmented ventilation and controlled mechanical ventilation in the healthy proband.
In 1998, laparoscopic radical prostatectomy with primary access to the seminal vesicles was introduced. In 1999, we developed a laparoscopic technique similar to the classic retropubic radical prostatectomy. We focus here on the continuous technical evolution of our technique.From March 1999 to May 2002, we performed 450 laparoscopic radical prostatectomies. All important data of the patients; data concerning the performance of the procedure, including technical modifications, conversion, reintervention, and complication rate; as well as follow-up information were documented contemporaneously. The patients were divided into three groups of 150 individuals each in order to analyze the influence of the technical evolution of the procedure. Additionally, we studied the transferability of our technique, comparing the learning curves of the three surgeons involved in the program.The technical modifications included the routine use of a voice-controlled robot (AESOP) for the camera, exposure of the apex with 120 degrees retracting forceps, a free-hand suturing technique instead of the Endostitch device for the dorsal vein complex, 5-mm clipping instead of bipolar coagulation for the nerve-sparing technique, initial 6 o'clock suturing of the urethra before complete division, control of the prostatic pedicles by use of 12-mm Hemo-lok clips instead of the Ultracision or Endo-GIA, the bladder neck-sparing technique in cases of T(1c) and T(2a) tumors, and interrupted instead of continuous sutures for the vesicourethral anastomosis. All these modifications resulted in a significant decrease in operating time and the rates of transfusion, open conversion, and reintervention. The introduction of the nerve-sparing technique increased the number of tumor-positive margins. The mean operating time of the third surgeon was significantly less than that of the first surgeon, but the transfusion, conversion, and reintervention rates did not differ significantly among the surgeons.Laparoscopic radical prostatectomy has undergone continuous technical evolution resulting in a significant improvement of the operative results. Although we were able to demonstrate the transferability of this difficult procedure, we feel that it should be performed only at centers of expertise.
The successful introduction of laparoscopic radical prostatectomy at the end of the last millennium represented a quantum leap in the technical development of minimally invasive surgery in urology. Therefore it seemed a logical step that, at the beginning of this millennium, first centers reported their initial experience with laparoscopic radical cystectomy. Based on more than 2000 laparoscopic radical prostatectomies, two centers have performed this procedure in 48 patients including a variety of urinary diversion (i.e. ileal conduit, ileal neobladder, sigmoid neobladder). In this article, all important surgical steps of laparoscopic radical cystectomy are presented, including the description of the most important techniques of urinary diversion. Based on our own experience, the results of 238 cases presented in the current literature are reviewed. The operating time mainly depended on the type and technique of urinary diversion and ranged between 352 and 430 minutes for ileal conduit, and between 478 and 649 minutes for orthotopic neobladder. The complication rate ranged between 16 and 18%, and the reintervention rate was 4-6%. Long-term follow-up is not available, disease-free survival after three years in a limited number of series ranges between 50 and 67%. No port site metastases have been reported so far. Even for the experienced surgeon laparoscopic radical cystectomy with urinary diversion represents a technically challenging procedure. Nevertheless, feasibility and safety have been proved by various authors. However, larger studies with long-term clinical outcome are necessary to determine the final value of the procedure.
