Neurologic Complications of Percutaneus Nephrolithotomy

Corresponding author: Hakan Öztürk Department of Urology, Sifa University School of Medicine, Fevzipasa Boulevard No: 172/2, 35240, Basmane-Konak, Izmir, Turkey Tel: +902324460880 / Fax: +902324460770 E-mail: [email protected] Submitted: January 21, 2014 / Accepted after revision: February 19, 2014 To the editor: Percutaneous nephrolithotomy (PCNL) was first reported by Fernstrom et al. [1] in 1976. After being defined as a novel extraction technique, the method has gained popularity by urologists. The technique has evolved over time and is still being advanced today. The main goal of researchers is to reduce undesirable outcomes of the technique and facilitate interventions for complex conditions including horseshoe kidneys and ectopic kidneys. With the introduction of laparoscopy-assisted PCNL techniques in recent years, the success rate of PCNL has increased. However, it should be noted that complication rates may have increased with these recent developments. PCNL-related complications are categorized according to the Clavien classification system. This system is treatment-oriented, which allows identification of procedure-related complications and management of the condition. The primary goal of the system modification is to standardize treatment approaches for urological diseases. PCNL-related complications vary widely from basic medical treatment and follow-up, to fatal events. The major and minor complication rate of PCNL is as high as 83% [2]. According to the Clavien grading system, grade I defines all events requiring a simple medical treatment. Bleeding requiring blood transfusion is one of the most frequently seen grade II PCNL complications (5.8%). The rate of mortality, which is defined as a grade V complication, is 0.1%. PCNL-related neurological complications are very rarely seen, with an incidence of below 0.1% (Table 1). However, such complications are of utmost importance, as they are extremely severe and early diagnosis can be difficult. Air embolisms were first defined as PCNL-related complications in 1984 by Miller et al. [3]. To date, the utilization of the pyelographic media, chemolytic agents, irritant solutions, and coagulating agents have been thoroughly scrutinized in the literature [3]. The first case of sudden death due to venous air embolism after PCNL was reported in 1985 [4]. Since then, air embolisms have been recognized as a complication of PCNL. In 2007, PCNL-induced paradoxical air embolism was defined. In this case, neurological complications resulted from an air embolism entering the paradoxical arterial system through a patent foramen ovale, which was essential for fetal circulation [5]. Paradoxical air embolisms may be caused by barotrauma/decompression sickness, penetrating trauma injuries, as well as during intracardiac shunting or cardiac surgery. It occurs when gas entering into the vein or the left heart and, thereby, systemic circulation, may lead to an arterial embolism [6,7]. Air embolisms are a very rare complication of PCNL. The most common causes of air embolism include direct airing of the venous system and utilization of air retrograde pyelogram during the procedure. Complication-related morbidity and mortality are associated with the air drift velocity, drifting volume pressure, patient poLetter