Elsevier

European Urology

Volume 53, Issue 1, January 2008, Pages 184-190
European Urology

Stone Disease
Classification of Percutaneous Nephrolithotomy Complications Using the Modified Clavien Grading System: Looking for a Standard

https://doi.org/10.1016/j.eururo.2007.06.049Get rights and content

Abstract

Objectives

A classification (modified Clavien system) has been proposed to grade perioperative complications. We reviewed our experience with percutaneous nephrolithotomy (PNL), grading the complications according to this new classification.

Methods

A total of 811 PNLs were performed between 2003 and 2006, and charts were retrospectively reviewed focusing on complications observed. According to the modified Clavien classification system, perioperative complications were stratified into five grades. Grade 1 defined all events that, if left untreated, would have a spontaneous resolution or needed a simple bedside intervention. Grade 2 complications required specific medication, including antibiotics and blood transfusion. Grade 3 complications necessitated surgical, endoscopic, or radiologic intervention (3a without general anesthesia, 3b under general anesthesia). Neighboring organ injuries and organ failures were classified as grade 4, and death was considered a grade 5 complication. Kidney stones treated with PNL were also classified as simple and complex and complication rates were compared.

Results

A total of 255 perioperative complications were observed in 237 (29.2%) patients. There were 33 grade 1 (4%), 132 grade 2 (16.3%), 54 grade 3a (6.6%), 23 grade 3b (2.8%), 9 grade 4a (1.1%), and 3 grade 4b (0.3%) complications, and 1 death (0.1%). Most complications were related to bleeding and urine leakage. Grade 2 and 3a complications were significantly more common in patients with complex renal stones.

Conclusions

A graded classification scheme for reporting the complications of PNL may be useful for monitoring and reporting outcomes. However, minor modifications concerning auxiliary treatments are needed and further studies are awaited.

Introduction

High success rates exceeding 90% are being reported with percutaneous nephrolithotomy (PNL) and modifications have further decreased the morbidity while maintaining efficacy [1], [2], [3]. However, complications after or during PNL may occur with an overall complication rate of up to 83%, including urinary extravasation (7.2%), bleeding necessitating transfusion (11.2–17.5%), and postoperative fever (21–32.1%), whereas major complications, such as septicemia (0.3–4.7%) and colonic (0.2–0.8%) or pleural injury (0.0–3.1%) are rare [4]. Comorbidities such as renal insufficiency, diabetes, morbid obesity, or cardiopulmonary diseases increase the risk of complications [5].

Although results from several large series on PNL from outstanding centers are reported in the literature, there is still no consensus on how to define complications and stratify them by severity. This hampers comparison of outcome data and generates difficulties in informing patients about PNL complications [1], [6], [7]. Several structured classifications of surgical complications exist in the literature, but none of them has been validated prospectively and their reproducibility is questionable [8], [9], [10], [11]. A new classification (modified Clavien system) has been proposed to grade perioperative complications of general surgery and has been validated in a cohort of 6336 patients [12]. The same classification system has recently been used by urologists to grade perioperative complications following laparoscopic radical prostatectomy, laparoscopic live donor nephrectomy, and retroperitoneoscopy [13], [14], [15].

Herein, we review our experience with PNL, to grade perioperative complications according to this new classification.

Section snippets

Patients and methods

Between 2003 and 2006, 811 PNL procedures were performed at our institution. Patient data, which was entered and maintained prospectively in our PNL registry, was evaluated in this study.

Preoperative complete blood count, serum creatinine, platelet count, bleeding and coagulation profile, and urine cultures were obtained from all patients. The use of anticoagulant drugs was stopped at least 1 wk before the operation. Radiologic evaluation included intravenous urography (IVU) and urinary tract

Results

Descriptive data of the cohort and the overall postoperative outcome are summarized in Table 2. At the 3-mo follow-up, an overall success rate of 91%, including CIRFs observed in 19.7%, was achieved. Auxiliary treatment alternatives, including SWL in 85, re-PNL in 22, and ureterorenoscopy (URS) in 7 patients, were performed in a total of 114 (14%) patients. Success rate for simple stones was 97% and 85% for complex stones.

A total of 255 complications were encountered in 237 (29%) patients.

Discussion

Despite high success rates, major concerns in percutaneous renal surgery involve serious complications such as blood loss, adjacent organ injuries, and life-threatening infections [5], [7], [17], [18], [19], [20]. Stratifying complications of PNL as major and minor ones, Lee et al reported major complications (ie, death, bleeding necessitating intervention, significant infection, urinary tract injury, and injuries to adjacent organs) in 6% of patients and minor complications (ie, postoperative

Conclusions

The modified classification presented in this report is the first of its kind for the PNL procedure. A graded classification scheme for reporting the complications of PNL may be useful for monitoring and reporting outcomes. It is also helpful in informing patients. The broad implementation of this classification may facilitate the evaluation and comparison of surgical outcomes among different surgeons and centers. However, minor modifications, especially concerning auxiliary treatments, are

Conflicts of interest

The authors have nothing to disclose.

References (26)

  • A. Srivastava et al.

    Vascular complications after percutaneous nephrolithotomy: are there predictive factors?

    Urology

    (2005)
  • R. Kukreja et al.

    Factors affecting blood loss during percutaneous nephrolithotomy: prospective study

    J Endourol

    (2004)
  • W.J. Lee et al.

    Complications of percutaneous nephrolithotomy

    AJR Am J Roentgenol

    (1987)
  • Cited by (0)

    Presented at the 22nd Annual European Association of Urology Congress, Germany, 21–24 March 2007.

    View full text