Rolf Herrmann Ringert

A new method for conservative renal surgery — experimental and first clinical results

ZusammenfassungZur Verlängerung der renalen Ischämie stehen bisher zwei Verfahren zur Verfügung: 1) eine Oberflächenkilhlüng mit Eis and 2) eine Perfusionskühlung mit einer extrazellulären Losung. Beide Methoden nutzen nur das Prinzip der Stoffwechselsenkung durch Kühlung. Während der Wiedererwärmung bei der Operation geht der Ischämieschutz verloren oder die Niere muß erneut gekiihlt werden. Deshalb sollte eine neue Protektionslösung den Energieverbrauch zusätzlich zur Kühlung auch durch ihre Zusammensetzung senken. Bei offenen Herzoperationen wird die HTK-Lösung nach Bretschneider bereits klinisch angewendet. In 71 Experimenten an Hundenieren wurde die Ischämiezeit durch diese Lösung von 15 auf 120 min bei 35°C and von 45 auf 360 min bei 25°C. verlängert. Nach 120 min Ischämie bei 30°C betrug die glomeruläre Filtrationsrate ca. 20 ml/min 100gFG innerhalb von 3 h Reperfusion. Nach 6 Tagen postoperativ war die GFR wieder 40 ml/min 100gFG. Es konnte kein ischämischer Schaden durch histologische Untersuchungen mehr festgestellt werden. Der klinische Nutzen dieser Methode konnte in 7 klinischen Anwendungen gezeigt werden. Die Ischamiezeit betrug bis zu 113 min and das Kreatinin lag zwischen 0,8 and 2,4 mg% am 6. postoperativen Tag. Dieses Protektionsverfahren führt also zu einer verbesserten Nierenfunktion in der postoperativen Phase. Eine längere Ischämiezeit wird von der Niere vertragen, and unter Anwendung dieser Technik wird eine ausgezeichnete Übersichtlichkeit während der Nierenoperation erreicht, was eine radikale Tumorexzision erleichtert.SummarySo far two methods for prolonging the tolerance of renal ischemia are available: 1) surface cooling with crushed ice and 2) perfusion cooling with an extracellular-like solution. Both methods use only the principle of reducing metabolism through cooling. While rewarming during surgery the ischemic protection is lost, or the kidney must be cooled once again. Therefore, a new preservation solution should reduce energy consumption due to its composition in addition to cooling. For open heart surgery, the HTK solution by Bretschneider is already used clinically. In 71 dog kidney experiments, the ischemic time kidneys could tolerate was prolonged by this solution from 15 to 120 min at 35°C and from 45 to 360 min at 25°C. After 2h of ischemia at 30°C glomerular filtration rate was about 20 ml/min · 100 gww within 3 h of reperfusion. After six postoperative days the filtration rate was 40 ml/min · 100 gww. No ischemic damage could be recognized by histological investigations. The clinical effectiveness of this method was shown in 7 clinical applications. Ischemic duration lasted up to 113 min, and blood creatinine was between 0.8 and 2.4 mg% at the 6th postoperative day. Use of this preservation technique thus leads to improved kidney function immediately following operation. Longer ischemia can be tolerated by a kidney thus protected, and using this technique excellent visibility can be achieved during intrarenal surgery, simplifying, for example, tumor extirpation.

Laser-supported partial laparoscopic nephrectomy for renal cell carcinoma without ischaemia time

BackgroundTo date, elective nephron-sparing surgery is an established method for the exstirpation of renal tumors. While open partial nephrectomy remains the reference standard of the management of renal masses, laparoscopic partial nephrectomy (LPN) continues to evolve. Conventional techniques include clamping the renal vessels risking ischaemic damage of the clamped organ. Thus, new techniques are needed that combine a sufficient tissue incision for exstirpation of the tumor with an efficient coagulation to assure haemostasis and abandon renal vessel clamping in LPN. Laser-excision of renal tumors during laparoscopic surgery seems to be a logical solution.MethodsWe performed nephron-sparing surgery without clamping of the renal vessels in 11 patients with a renal tumor in exophytic position (mean size 32 mm, ranging 8–45 mm) by laser-supported LPN.ResultsRegular ultrasound monitoring and insertion of a temporary drainage showed no evidence of postoperative hemorrhage. All tumors were removed with a histopathologically confirmed surrounding margin of normal renal tissue (R0 resection). Serum creatinine, hemoglobin, and hematocrit were nearly unaltered before and after surgery.ConclusionsThe experience won in these patients have confirmed that laser-assisted LPN without clamping of the renal vessels could be a safe and gentle alternative to classic partial nephrectomy in patients with exophytic position of renal tumors.

Improvement of In Situ Renal Protection Against Complete Ischemia Through the Replacement of Chloride by Aspartate in the HTK Solution of Bretschneider

The cardioplegia solution, HTK (histidine-tryptophan-ketoglutarate) (Bretschneider et al. 1975, 1984; Bretschneider 1980), was primarily developed to improve myocardial protection, as compared with periods of ischemia, during artificial cardiac arrest in open heart surgery. It has since become a routine clinical procedure (Preusse et al. 1987). According to our results, this solution also significantly improves ischemic tolerance of kidneys (Kallerhoff et al. 1985a, b, 1986, 1987c). The superiority over simple ischemia or over the Euro Collins solution holds for “cold” as well as for “warm” ischemia (Kallerhoff et al. 1988a). Renal ischemic tolerance was increased from 15–20 min to 2 h at normothermia (Kallerhoff et al. 1986). There have now been several clinical applications of this method (Blech et al. 1988; Kallerhoff et al. 1988b).