THORACIC COMPLICATIONS DURING UROLOGICAL LAPAROSCOPY

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1 /04/ /0 Vol. 171, , April 2004 THE JOURNAL OF UROLOGY Printed in U.S.A. Copyright 2004 by AMERICAN UROLOGICAL ASSOCIATION DOI: /01.ju SIDNEY C. ABREU, DAVID S. SHARP, ANUP P. RAMANI, ANDREW P. STEINBERG, CHRISTOPHER S. NG, MIHIR M. DESAI, JIHAD H. KAOUK AND INDERBIR S. GILL* From the Section of Laparoscopic and Minimally Invasive Surgery, Glickman Urological Institute, Cleveland Clinic Foundation, Cleveland, Ohio ABSTRACT Purpose: We documented thoracic related complications during urological laparoscopic surgery. Materials and Methods: A total of 1,129 patients underwent major urological laparoscopic procedures in a 5-year period. Operative reports and postoperative radiographic reports were retrospectively reviewed to identify patients with thoracic related medical and surgical sequelae. Of the patients 619 (55%) underwent at least 1 chest x-ray in the immediate or early postoperative period. In the remaining 510 patients (45%) there was no clinical indication to perform chest x-ray. Results: Of 619 patients undergoing chest x-ray 438 (71%) were completely normal. Medical pulmonary complications, surgical thoracic complications and subclinical, incidentally detected gas collections in the chest were identified in 12.6%, 0.5% and 5.5% of patients, respectively. Medical complications in 12.6% of cases included pulmonary infiltrate/atelectasis in 9.7%, pleural effusion in 4.8% and pulmonary embolus in 0.3%. Surgical complications included symptomatic pneumothorax in 4 patients (0.35%), hemothorax in 1 (0.08%) and chylothorax in 1 (0.08%). Subclinical abnormal thoracic gas collections were radiographically noted in 34 of the 619 patients (5.5%) on chest x-ray, including pneumomediastinum in 19 (3.1%), pneumothorax in 10 (1.6%) and pneumopericardium in 5 (0.8%). Overall 36 of 40 (90%) thoracic surgical complications (3) and subclinical, incidentally detected gas collections (33) occurred during retroperitoneal laparoscopy. Re-intervention was necessary in 6 patients (0.5%), namely pulmonary embolus requiring vena caval filter placement in 3 (0.3%), pneumothorax requiring a chest tube in 2 (0.17%) and hemothorax requiring emergency open thoracotomy in 1 (0.08%). No patient underwent open conversion to complete the initial proposed operation. Conclusions: Due to its high solubility the expectant management of incidental CO 2 pneumothorax, pneumopericardium and pneumomediastinum is recommended initially in the clinically stable patient. Inadvertent diaphragmatic entry can be satisfactorily repaired laparoscopically without open conversion. Although it is rare, surgical thoracic complications are potentially life threatening, requiring prompt identification and management. KEY WORDS: intraoperative complications, laparoscopy, urologic surgical procedures, diaphragm, thoracic injuries Laparoscopic urology has evolved from relatively simple and limited techniques to encompass a variety of sophisticated procedures. As the complexity and number of laparoscopic cases expand, an increase in the number, magnitude and spectrum of surgical related complications is inevitable. To date single and multi-institutional reviews regarding laparoscopic complications have been published, commonly focusing on vascular and visceral injuries. 1 3 Thoracic complications associated with urological laparoscopic surgery have not been reported in detail. A recent multi-institutional study focused specifically on the incidence of pleural injury during laparoscopic renal surgery. 4 Our broader study documents the overall incidence of thoracic related complications associated with urological laparoscopy in 3 categories, namely medical pulmonary complications, surgical thoracic complications and subclinical, incidentally detected gas collections in the thorax. In regard to surgical thoracic complications, a detailed analysis of possible etiology, diagnosis, management and prevention is presented. Accepted for publication November 14, * Correspondence and requests for reprints: Section of Laparoscopic and Minimally Invasive Surgery, Glickman Urological Institute, A100, Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, Ohio (telephone: ; FAX: ; gilli@ccf.org) MATERIALS AND METHODS All 1,129 patients undergoing major transperitoneal and extraperitoneal laparoscopic urological procedures in the 5-year period from 1997 were included (table 1). Data were retrospectively collected from individual operative reports, hospital discharge summaries and postoperative chest x-ray reports. Pulmonary embolus was identified by reviewing patient discharge summaries. For identified patients with a thoracic related complication hospital records were reviewed to obtain relevant demographic and clinical (intraoperative and postoperative) data. In our early laparoscopic experience all patients underwent chest x-ray routinely in the recovery room. With evolving experience chest x-rays were done postoperatively only if there was any clinical suspicion of a thoracic complication. RESULTS Of the 1,129 patients chest x-ray was not deemed clinically necessary in 510 (45%). None of these patients experienced any clinically evident intraoperative or postoperative pulmonary or thoracic complication. In 619 patients (55%) at least 1 chest x-ray was performed postoperatively for various reasons. It was completely normal in 437 patients (71%). In 142 patients (12.6%) a total of 166 medical pulmonary complica-

2 1452 TABLE 1. Laparoscopic procedures Transperitoneal Extraperitoneal Total Radical nephrectomy Partial nephrectomy Nephroureterectomy Renal cryoablation Donor nephrectomy Simple nephrectomy Adrenalectomy Radical prostatectomy Totals (%) 583 (51.6) 546 (48.4) 1,129 tions occurred, including atelectasis/infiltrate in 109, pleural effusion in 54 and pulmonary embolus in 3 (tables 2 and 3). All medical pulmonary complications were managed conservatively except in the 3 patients with pulmonary embolus who underwent percutaneous placement of an inferior vena caval filter. Thoracic surgical complications occurred in 6 patients (0.5%), namely pneumothorax in 4, hemothorax in 1 and chylothorax in 1. Incidentally detected, subclinical thoracic gas collections were identified on chest x-ray in 34 of 619 patients (5.5%), including pneumomediastinum in 19, pneumothorax in 10 and pneumopericardium in 5 (tables 2 and 4). These incidental radiological findings resolved spontaneously in all 34 patients. No patient underwent open conversion to complete the initial proposed operation. Only 1 patient (0.08%) required open reexploration of the thorax in the entire series. There was no patient mortality due to a thoracic complication. Although there were an equivalent number of transperitoneal and retroperitoneal procedures, retroperitoneal laparoscopy was associated with a higher incidence of abnormal gas collections (transperitoneal 3 and retroperitoneal 33). However, all of these radiographic findings were incidental and asymptomatic, requiring no further intervention. On the other hand, the incidence of thoracic complications that required additional surgical intervention during transperitoneal and retroperitoneal laparoscopy was similar at 1 and 3 cases, respectively. Table 5 lists the details of thoracic surgical complications and incidental thoracic gas collections. Pneumothorax. Pneumothorax in 14 patients was subclinical in 10 and clinically significant in 4. Subclinical pneumothorax in 10 cases was identified incidentally on postoperative chest x-ray. In each instance the laparoscopic procedure was uneventful and without any intraoperative or postoperative sequelae. With an apical location in 6 patients radiological pneumothorax was tiny or small in all 10 patients. Complete spontaneous resolution of pneumothorax was documented on repeat chest x-ray in all 10 patients. Clinically significant pneumothorax occurred in 4 patients, requiring intraoperative (2) or early postoperative (2) intervention. A 78-year-old male underwent uneventful retroperitoneoscopic right radical nephrectomy. Routine postoperative chest x-ray revealed extensive right pneumothorax with lung collapse. Despite the size of the pneumothorax the patient TABLE 3. Medical pulmonary complications Pleural Effusion Atelectasis/ Infiltrate Pulmonary Embolism* Total Radical nephrectomy Partial nephrectomy Nephroureterectomy Cryoablation Donor nephrectomy Simple nephrectomy 2 2 Adrenalectomy Radical prostatectomy Totals * Confirmed on ventilation-perfusion scan and all 3 patients underwent inferior vena caval filter placement without mortality. was asymptomatic. A thorocostomy tube was placed with the patient in the recovery room. A 59-year-old male underwent retroperitoneoscopic left simple nephrectomy for a nonfunctional hydronephrotic kidney. Intraoperatively sudden hypotension (systolic pressures to 90 mm Hg) occurred. Immediate desufflation rapidly stabilized the clinical condition. Intraoperative chest x-ray confirmed large left pneumothorax. Since the patient remained hemodynamically stable, the laparoscopic procedure was completed at decreased pneumoperitoneum pressure (10 mm Hg). Subsequently the retroperitoneal space was filled with irrigation fluid and air bubbles were observed originating from the vicinity of the posterior 12 mm port. On retracting this port a small pleurotomy could be clearly identified at the inferior edge of this port site. Through this port a 14Fr rubber catheter was inserted directly into the pleural space. Figure-of-8 stitches were placed laparoscopically to repair the pleural injury around the rubber catheter, which was attached to continuous water seal suction. A 74-year-old female undergoing transperitoneal partial nephrectomy for a 4.5 cm upper pole right renal tumor experienced a small diaphragmatic entry during liver retraction. Since hemodynamic and ventilatory parameters remained stable, laparoscopic partial nephrectomy was completed and the diaphragmatic rent was repaired thereafter. No chest tube was placed. Finally, a 72- year-old male, American Society of Anesthesiologists class 3 with a history of severe chronic obstructive pulmonary disease underwent retroperitoneoscopic right renal cryoablation. Postoperative chest x-ray showed persistent right infiltrate, effusion and a small (less than 20%) pneumothorax. Because he was symptomatic, a chest tube was placed. However, air leakage persisted for several days. Pleurodesis was performed on day 12 and the chest tube was removed 4 days later. Hemothorax. Acute hemothorax occurred in a 73-year-old woman undergoing retroperitoneoscopic cryoablation for a 2.6 cm tumor in a solitary left kidney. Because of her particular body habitus and obesity (body mass index 36) bony landmarks were difficult to palpate, resulting in undiagnosed supracostal placement of the posterior port. Cryoablation Pts TABLE 2. Medical and surgical thoracic complications Chest X-Ray Complications Incidental Abnormal Gas Collections Postop Normal Postop Medical Pulmonary* Surgical Thoracic Radical nephrectomy Partial nephrectomy Nephroureterectomy Renal cryoablation Donor nephrectomy Simple nephrectomy Adrenalectomy Radical prostatectomy Totals 1, (142 pts, 12.6%) 6 (1,129 pts, 0.5%) 33 (619 chest x-rays, 5.5%) * Including 3 cases of pulmonary embolism treated with inferior vena caval filter placement without mortality.

3 1453 TABLE 4. Surgical thoracic complications and abnormal gas collections in the chest Chest Tube Pneumothorax No Chest Tube Hemothorax Chylothorax Pneumomediastinum Pneumopericardium Radical nephrectomy Partial nephrectomy 5* 6 11 Nephroureterectomy Cryoablation Donor nephrectomy Simple nephrectomy 1* 1 2 Adrenalectomy Radical prostatectomy 1 1 Totals * Intraoperative diaphragmatic repair in 1 patient. Concomitant pneumothorax in 1 patient. Concomitant pneumomediastinum in 1 patient. Total TABLE 5. Impact of laparoscopic technique on thoracic complications and abnormal gas accumulation in chest Access Transperitoneal Retroperitoneal pts Pneumothorax: Radical nephrectomy 3* Partial nephrectomy 2 3 Renal cryoablation 3* Donor nephrectomy 1 Simple nephrectomy 1 Radical prostatectomy 1 Pneumomediastinum: Radical nephrectomy 1 3 Partial nephrectomy 6 Nephroureterectomy 2 Renal cryoablation 3 Donor nephrectomy 2 Adrenalectomy 2 Pneumopericardium: Nephroureterectomy 1 Renal cryoablation 1 Donor nephrectomy 1 Adrenalectomy 2 Chylothorax, simple nephrectomy 1 Hemothorax, renal cryoablation Totals (%) 4 (0.7) 36 (6.6) Of the 40 surgical complications and abnormal intrathoracic gas collections 4 (10%) and 36 (90%) occurred following transperitoneal and 36 retroperitoneal laparoscopy, respectively. * Chest tube in 1 patient. Intraoperative repair of diaphragmatic entry in 1 patient. was completed successfully. In the recovery room the patient was hypotensive and chest x-ray demonstrated whiteout of the left hemithorax. A tube thoracostomy was inserted with the return of fresh blood. Emergency open thoracotomy identified an intercostal arterial bleeder, which was suture ligated. In addition, a 3 cm diaphragmatic rent created by the supracostal port was identified and suture repaired. A chest tube was inserted, which was removed on postoperative day 6. Chylothorax. A 40-year-old female with diabetes, hypertension and a well functioning kidney transplant underwent synchronous bilateral retroperitoneal laparoscopic native nephrectomy for large, locally symptomatic autosomal dominant polycystic kidneys. On day 4 postoperatively the patient returned to the emergency room complaining of sharp left pleuritic pain with mild shortness of breath. Chest computerized tomography (CT) scan revealed a large left pleural effusion causing collapse of the left lower lung. Abdominal CT did not reveal any retroperitoneal fluid collection. Pleurocentesis retrieved 300 cc of milky chylous fluid high in chylomicrons and triglyceride. Chylothorax was treated conservatively with a low fat diet and medium chain triglyceride supplementation. Pneumomediastinum and pneumopericardium. Routine postoperative chest x-rays identified a small incidental pneumomediastinum in 19 patients (3.1%). Of these patients 18 (93%) had undergone a retroperitoneoscopic procedure. Pneumopericardium was radiologically identified incidentally in 5 asymptomatic cases (0.8%) following retroperitoneoscopic procedures. None of these 24 patients had any cardiopulmonary sequelae and no additional intervention was required. DISCUSSION Pneumothorax following abdominal laparoscopic procedures can result from a variety of causes. In our series 10 patients had pneumothorax without obvious iatrogenic pleural or diaphragmatic injury. Congenital diaphragmatic defects, such as a patent pleuroperitoneal canal or attenuated areas in the diaphragm due to improper embryonic fusion, may allow peritoneal CO 2 to gain access into the pleural space. 5 7 Retroperitoneally insufflated CO 2 can dissect along natural musculofascial planes into the mediastinal space. After it is inside the mediastinum CO 2 can gain entry into the pleural cavity through the pulmonary hilum, dissecting along pulmonary vasculature, or through a rupture in the mediastinal pleura, resulting in pneumothorax formation. 5, 7 Apical pneumothorax can occur due to the rupture of apical blebs from barotrauma (positive pressure during mechanical ventilation). 6 Needle aspiration of pneumothorax could determine whether it occurred due to endotracheal anesthesia and positive pressure ventilation or to tissue propagation of carbon dioxide. Other anesthesia related issues, such as pleural injury during central line placement or elevated maximum end tidal CO 2 pressure, can be potentially causative. 6 In our series 11 of 14 patients (79%) with pneumothorax had undergone retroperitoneal laparoscopy (table 5). During retroperitoneoscopy subcutaneous emphysema extending up to the neck could potentially allow CO 2 to enter the superior mediastinum and apical pleural space. 5 7 Asymptomatic CO 2 pneumothorax usually reabsorbs readily, lending itself to conservative management. In our series complete spontaneous resolution of asymptomatic pneumothorax occurred in all 10 patients. Inadvertent pleural or diaphragmatic injury is an obvious cause of pneumothorax during open or laparoscopic renal surgery. 8 In a series of 253 open flank operations pleural injury occurred in 63 (25%). 9 In another series of 130 open extraperitoneal live donor nephrectomies pleurotomy occurred in 11 (8.5%). 8 Pleural or diaphragmatic injuries can occur during 2 specific aspects of a laparoscopic procedure, namely port insertion and tissue dissection. Del Pizzo et al recently documented pleural injury in 0.6% of 1,765 patients undergoing laparoscopic renal surgery at 4 institutions. 4 Pleurotomy occurred during transperitoneal laparoscopy (8 patients), while mobilizing the kidney (6) or liver (2) and during retroperitoneal port placement (2). In our series 2

4 1454 pleural/diaphragmatic injuries occurred during port insertion for retroperitoneoscopy. In 1 patient morbid obesity prevented adequate palpation and identification of the 12th rib, resulting in supracostal port placement with subsequent pleural and diaphragmatic injury. In our second case the posterior 12 mm port transgressed the most inferior edge of the pleura, resulting in pneumothorax. Following the precise identification of pleural entry it was successfully repaired laparoscopically. An additional 2 patients experienced large pneumothorax that was recognized only postoperatively, necessitating chest tube drainage. In each case, although no frank pleural or diaphragmatic injury was detected intraoperatively, we cannot rule it out. In an open series of 253 flank procedures 2 patients had postoperative pneumothorax without any intraoperative recognition of pleurotomy. 9 As such, a high index of suspicion should be maintained since pleural or diaphragmatic injury may not always be recognized intraoperatively. Chylothorax, defined as an accumulation of pleural fluid rich in lipids, is a rare, surgical related thoracic complication. To our knowledge there is no previous report of chylothorax following a laparoscopic renal procedure. A review of the literature revealed a single case of concomitant chylothorax and chyloretroperitoneum following open radical nephrectomy. 10 In this case a small incidental pleurotomy had occurred and been repaired intraoperatively. The authors hypothesized that primary chyloretroperitoneum formed, which then entered the chest. In our case no concomitant chyloretroperitoneum was evident on abdominal CT and no diaphragmatic rent was evident during the laparoscopic operation. However, extensive bilateral retroperitoneal dissection had been necessary to circumferentially mobilize the 2 large specimens (right kidney cm and 1.8 kg, and left kidney cm and 1.5 kg). It is possible that such wide dissection may have injured a sizable retroperitoneal lymphatic channel that communicated with the pleural cavity, resulting in chylothorax. Additional possible etiologies for chylothorax include iatrogenic cisterna chyli obstruction and spontaneous chylothorax. 11 Our case was successfully managed by pleurocentesis and dietary manipulation with a low fat, medium chain triglyceride diet. Pneumomediastinum was another incidental roentgenogram abnormality in our study. For pneumomediastinum to occur during transperitoneal laparoscopy abdominally insufflated CO 2 must track through the aortic and esophageal hiatus into the mediastinum. 5, 7 During retroperitoneal laparoscopy the lack of subdiaphragmatic peritoneum may facilitate cephalad tracking of CO 2 along the aorta and vena cava toward the mediastinum. 5, 7 Therefore, pneumomediastinum may be more likely to occur during retroperitoneoscopy. In reviewing 63 chest x-rays following laparoscopic renal surgery Wolf et al identified asymptomatic pneumomediastinum not related to iatrogenic pleural injury in 8 cases (13%). 12 Incidental pneumomediastinum occurred more commonly after extraperitoneal procedures compared to transperitoneal laparoscopy (30% vs 4.6%). Of the 19 patients with pneumomediastinum in our series 18 (93%) had undergone retroperitoneal laparoscopy. Pneumopericardium was incidentally noted on chest x-ray in 5 asymptomatic patients in our series, of which the etiology is unclear. Persistent embryological communication between the pericardial and peritoneal cavities or the rupture of accumulated mediastinal CO 2 beside a blood vessel is a possible etiological mechanism. 5, 6, Although pneumopericardium could potentially result in cardiac tamponade syndrome, none of our patients had any related clinical symptoms. In our study 76% of chest x-rays were done in the recovery room with a portable x-ray machine. We recognize that the patient head was only moderately elevated for these studies and inadequate inspiration due to postoperative pain may have further compromised the quality of the radiographs. It is conceivable that if upright anteroposterior and lateral chest x-rays had been obtained in all patients, the incidence of subclinical thoracic abnormalities may have been higher. Nevertheless, we believe that this 5.5% incidence of subclinical abnormal thoracic gas accumulations is as accurate as possible without a prospective study. The complication rate reported in this study is favorable compared to that in similar studies of open urological procedures (table 6). Based on our experience certain preventive strategies can be proposed. During transperitoneal laparoscopy care should be taken not to injure the diaphragm while mobilizing the spleen and liver. If a diaphragmatic or pleural injury is recognized intraoperatively, the anesthesiologist should be notified immediately. Usually with careful adjustment of ventilatory parameters the patient remains clinically stable, allowing completion of the proposed laparoscopic procedure and repair of the diaphragmatic rent. During port placement for retroperitoneal laparoscopy in obese patients when the bony landmarks are not clearly identifiable, intraoperative ultrasonography can be done to locate precisely the 12th rib, thus, avoiding inadvertent supracostal port placement. When creating the retroperitoneal space, the balloon dilator should be positioned anterior to the psoas muscle and fascia. This maneuver prevents stripping the psoas muscle of its investing fascia and minimizes cephalad tracking of CO 2 along the psoas muscle fibers into the thoracic cavity. 7 We routinely use a Bluntip trocar (United States Surgical Corp., Norwalk, Connecticut) as the primary port to prevent subcutaneous emphysema. 7 This trocar has an internal fascial retention balloon and an external adjustable foam cuff, which combine to achieve an airtight seal, thus, eliminating air leakage at the primary port site. Additional recommendations for preventing abnormal thoracic gas collections during transperitoneal and retroperitoneal laparoscopy include full relaxation of the abdominal muscles as well as the avoidance of coughing and straining during laparoscopic procedures. 13 These precautions avoid sudden elevations of abdominal pressure above 20 mm Hg, which may potentially force abdominal CO 2 through the diaphragmatic hiatus into the mediastinum. TABLE 6. Thoracic complications associated with open renal surgery References Open Pts Intraop Pleural Injury Pneumothorax Chest Tube Olsson et al 8 Radical nephrectomy Poore et al 9 Flank operation * Dunn et al 16 Nephrectomy Not reported Farrell et al 17 Live donor nephrectomy Uehling et al 18 Live donor nephrectomy Weinstein et al 19 Live donor nephrectomy Scott and Selzman 20 Live donor nephrectomy Totals 1, (10%) 14 (1.2%) * Needle aspiration.

5 1455 CONCLUSIONS Due to its high solubility expectant management of CO 2 pneumothorax, pneumopericardium and pneumomediastinum in the select clinically stable patient with close monitoring and serial chest x-rays is advocated with more aggressive measures reserved for the symptomatic patient. Intraoperatively identified, inadvertent pleural or diaphragmatic entry can usually be repaired laparoscopically without open conversion. Although small, asymptomatic, subclinical, spontaneously resolving gas collections in the chest are more common with retroperioneoscopy, the incidence of symptomatic or serious thoracic complications is similar between transperitoneal and retroperitoneal laparoscopy. REFERENCES 1. Bishoff, J. T., Allaf, M. F., Kirkels, W., Moore, R. G., Kavoussi, L. R. and Schroder, F.: Laparoscopic bowel injury: incidence and clinical presentation. J Urol, 161: 887, Siqueira, M. T., Jr., Kou, R. L., Gardner, T. A., Paterson, R. F., Stevens, L. H., Lingeman, J. E. et al: Major complications in 213 laparoscopic nephrectomy cases: the Indianapolis experience. J Urol, 168: 1361, Meraney, A. M., Abd-el Samee, A. and Gill, I. S.: Vascular and bowel complications during retroperitoneal laparoscopic surgery. J Urol, 168: 1941, Del Pizzo, J. J., Jacobs, S. C., Bishoff, J. T., Kavoussi, L. R. and Jarrett, T. W.: Pleural injury during laparoscopic renal surgery: early recognition and management. J Urol, 169: 41, Wolf, J. S., Jr. and Stoller, M. L.: The physiology of laparoscopy: basic principles, complications and other considerations. J Urol, 152: 294, Venkatesh, R., Kibel, A. S., Lee, D., Rehman, J. and Landman, J.: Rapid resolution of carbon dioxide pneumothorax (capnothorax) resulting from diaphragmatic injury during laparoscopic nephrectomy. J Urol, 167: 1387, Ng, C. S., Gill, I. S., Sung, G. T., Whalley, D. G., Graham, R. and Schweizer, D.: Retroperitoneoscopic surgery is not associated with increased carbon dioxide absorption. J Urol, 162: 1268, Olsson, L. E., Swana, H., Friedman, A. L. and Lorber, M. I.: Pleurotomy, pneumothorax, and surveillance during living donor nephroureterectomy. Urology, 52: 591, Poore, R. E., Sexton, W. J., Hart, L. J. and Assimos, D. G.: Is radiographic evaluation of the chest necessary following flank surgery? J Urol, 155: 849, Cespedes, R. D., Peretsman, S. J. and Harris, M. J.: Chylothorax as a complication of radical nephrectomy. J Urol, 150: 1895, Garcia Restoy, E., Bella Cueto, F., Espejo Arenas, E. and Aloy Duch, A.: Spontaneous bilateral chylothorax: uniform features of a rare condition. Eur Respir J, 1: 872, Wolf, J. S., Jr., Monk, T. G., McDougall, E. M., McClennan, B. L. and Clayman, R. V.: The extraperitoneal approach and subcutaneous emphysema are associated with greater absorption of carbon dioxide during laparoscopic renal surgery. J Urol, 154: 959, Doctor, N. H. and Hussain, Z.: Bilateral pneumothorax associated with laparoscopy. A case report of a rare hazard and review of literature. Anesthesia, 28: 75, Nicholson, R. D. and Berman, N. D.: Pneumopericardium following laparoscopy. Chest, 76: 605, Knos, G. B., Sung, Y. F. and Toledo, A.: Pneumopericardium associated with laparoscopy. J Clin Anesth, 3: 56, Dunn, M. D., Portis, A. J., Shalhav, A. L., Elbahnasy, A. M., Heidorn, C., McDougall, E. M. et al: Laparoscopic versus open radical nephrectomy: a 9-year experience. J Urol, 164: 1153, Farrell, R. M., Stubenbord, W. T., Riggio, R. R. and Muecke, E. C.: Living renal donor nephrectomy: evaluation of 135 cases. J Urol, 110: 639, Uehling, D. T., Malek, G. H. and Wear, J. B.: Complications of donor nephrectomy. J Urol, 111: 745, Weinstein, S. H., Navarre, R. J., Loening, S. A. and Corry, R. J.: Experience with live donor nephrectomy. J Urol, 124: 321, Scott, R. F., Jr. and Selzman, H. M.: Complications of nephrectomy: review of 450 patients and a description of a modification of the transperitoneal approach. J Urol, 95: 307, 1966