Prediction of morbidity and mortality after percutaneous nephrolithotomy by using the Charlson Comorbidity Index

OBJECTIVES

To determine whether the Charlson Comorbidity Index (CCI) predicts postoperative medical complications and death in patients treated with percutaneous nephrolithotomy (PCNL).

METHODS

A total of 1406 PCNL procedures were performed at 4-stone referral centers between September 2004 and March 2011 were reviewed in this multicenter study. Variables included patient and stone characteristics, preoperative comorbidities, intraoperative data, and postoperative complications, including mortality.

RESULTS

The present study included 868 (61.7%) men and 538 (38.3%) women. Mean patient age was 44.1 years (range 1-81). CCI score was calculated as "0" for 993 patients (70.6%, called group I), "1" for 316 patients (22.5%, called group II) and"≥2" for 97 patients (6.9%, called group III). The incidence of comorbidities increased with age (P=.001). The overall postoperative complication rate was 29.3%. Life-threatening medical complications developed in 2.9% of patients in group I, 7.6% of patients in group II, and 21.6% of patients in group III, (P=.001). There were 3 deaths for an overall 0.2% mortality rate. Perioperative bleeding requiring blood transfusion was observed in 9.5% of patients, and we found an increased risk of hemorrhage associated with CCI score (P=.049). High CCI score, patient age, hemorrhage, and operative time were significantly related to higher medical complication rates after PCNL.

CONCLUSIONS

CCI is a quick, simple, and reproducible scoring system that accurately predicts the morbidity and mortality of PCNL.

Tissue effects of intracorporeal lithotripsy techniques during percutaneous nephrolithotomy: comparison of pneumatic and ultrasonic lithotripters on rat bladder

The objectives of this study were to determine the tissue effects of ultrasonic and pneumatic lithotripsy on the rat urothelium. The rats were divided into three groups. Groups I and II consisted of ten rats each that underwent intracorporeal lithotripsy (pneumatic and ultrasonic lithotripsy, respectively). Group III contained ten control rats and no lithotripsy method was used, they served as references for absence of injury. The light microscopy findings were evaluated as follows: squamous metaplasia, papillary projection, inflammation, increased stratification, and stone formation. In five (71.4%) animals of group II, bladders were edematous and hemorrhagic, macroscopically. Histologically, the bladder wall was normal in four rats of group I and in one of group II. There was a significant increase in inflammation (31.5%), squamous metaplasia (85.7%), papillary projection (71.4%), increased stratification (71.4%), and microscopic or macroscopic stone formation (85.7%) in the bladder wall of group II rats in comparison with group I and control group. In the rat model, we noted that ultrasonic devices have a potential risk for tissue injury. In turn, this was associated with a markedly increased deposition of CaOx stones in the kidney. When confronted with harder stones, pneumatic lithotripsy can be more effective while also minimizing tissue injury.