Analysis of the first 100 cases of percutaneous nephrolithotomy in the learning curve

Ahmet Yaser MÜSLÜMANOĞLU,Ahmet TEFEKLİ,Aytül TAŞ,Timuçin ÇAKIR,Ömer SARILAR

Abstract

Introduction: Due to problems in equipment supply, percutaneous nephrolithotomy (PCNL), a standard treatment alternative in many renal stones, is only performed in selected centers in our country. In this report, we assessed our initial results of 100 cases performed in a 10-month period. Materials and Methods: During a period between October 2002 and August 2003, a total of 100 patients underwent PCNL. Percutaneous renal access was done under C-armed flouroscopy with patient in prone position. The tract was dilated with a balloon dilatator and a 30F Amplatz sheet was placed. Percutaneous stone disintegration and removal was performed with a 26 Fr rigid nephroscope and pneumatic lithotriptor. A 14F nephrostomy tube was placed at the end of each procedure. Results of the first and last 50 cases were compared. Results: The mean age of patients enrolled to the study was 41.1±13.5 (range: 18-75) years. There were 46 women and 54 men. The size of stones treated ranged between 2 to 20 cm2. There were 33 isolated renal pelvis stones, 15 isolated caliceal stones, 3 caliceal diverticular stones, 2 upper ureteral stones, 5 partial and 7 complete staghorn stones, 20 renal pelvis stones accompanying lower caliceal stones and 15 renal pelvis stones accompanying multiple caliceal stones. Percutaneous renal access was performed below the 12th rib in all cases, except 1. Overall, the preparation and positioning period ranged between 30 to 45 minutes, and the mean percutaneous procedure time was 53.4±32.5 (range: 25-150) minutes. Mean preparation and procedure times were both longer in 1st fifty cases (p<0.05). Need for accessory treatment was also higher in the former group. Overall, a complete stone-free rate of 60% was achieved, and clinically insignificant residual fragments were observed in 31%. Stone-free rates were 50% and 70% in the 1st and last 50 cases, respectively (p<0.05). PCNL resulted in failure in 6% of cases in the latter group, while 12% of cases in the former group resulted in failure (p<0.05). Stone-free rates in simple, isolated stones and complex stones were 79.2% and 38.3%, respectively. PCNL treatment did not result in failure in any case with simple, isolated stone, while unsuccessful outcome was observed in 19.3% of cases with complex stones. Immediate open surgical exploration was not indicated in any case. Complication rates did not significantly differ in between groups. Bleeding necessitating blood transfusion was observed in 6%, perinephritic abscess formation in 1% and hydrotorax in 1%. Conclusion: As evident in the literature, success rates with PCNL may exceed 90%. Our results indicate that stone-free rates increase while operation times and need for accessory treatment decrease with increasing experience following 50 cases, and that complex stones significantly diminish success rates in the learning curve.

Özet

Ülkemizde sayılı merkezde perkütan nefrolitotomi (PCNL) uygulanabilmektedir. Çalışmamızda, 10 ayda uyguladığımız 100 olgunun sonuçlarını irdeledik. Ekim 2002- Ağustos 2003 tarihleri arasında 100 hastaya PCNL uygulandı. C-kollu floroskopi cihazı olan ürolojik masada perkütan olarak böbreğe giriş yapıldı ve balon dilatatör ile 30 F kılıfın yerleşeceği yol hazırlandı. İşlemler 26 F nefroskopla yapıldı ve taşların parçalanmasında pnömotik litotriptör kullanıldı. İlk 50 ve son 50 olgunun sonuçları karşılaştırıldı. Tedavi edilen olguların yaş ortalaması 41.1±13.5 yıl (18-75 yıl) olup, 46’sı bayan, 54’ü erkekti. Taşların boyutu 2-20 cm2 arasında değişmekteydi. Perkütan böbrek girişlerin 1’i hariç tümü 12. kotun altından yapıldı. PCNL için hazırlık süresi 30-45 dakika arasındaydı ve cerrahi işlem süresi ortalama 53.4±32.5 dakikaydı (25-150 dakika). Gerek hazırlık gerekse işlem süresi ilk 50 olguda anlamlı olarak daha uzundu (p<0.05). Ek tedavi gereksinimi ilk 50 olguda daha fazlaydı. Olguların toplam %60’ında taşsızlık sağlanırken, %31’inde klinik önemi olmayan reziduel fragmanlar gözlendi. Taşsızlık oranları, ilk 50 olguda %50, son 50 olguda ise %70’di (p<0.05). Son 50 olgunun %6’sında PCNL başarısızlıkla sonuçlanırken, ilk 50 olguda bu oran %12’ydi (p<0.05). Komplikasyon oranları açısından gruplar arasında fark gözlenmedi. Böbrek taşlarının PCNL ile tedavisinde %90 başarı sağlanmakta, artan tecrübeyle taşsızlık oranın artmakta, işlem süresinin kısalmakta ve ek tedavi gereksiniminin azalmaktadır.