Int Urol Nephrol DOI 10.1007/s11255-014-0726-x
UROLOGY - ORIGINAL PAPER
Hand-assisted laparoscopic radical nephrectomy in pregnancy Zsolt Domja´n • Endre Holman • Noe´mi Borda´s • Alexander Stephan Da´kay • Kiarash Bahrehmand Istva´n Buzoga´ny
•
Received: 7 March 2014 / Accepted: 21 April 2014 Ó Springer Science+Business Media Dordrecht 2014
Abstract Purpose To demonstrate the beneficial results of handassisted laparoscopic tumor nephrectomy in pregnancy and to emphasize the proper timing of such surgery for its crucial importance attempting to avoid fatal cancer-related outcomes as a result of late interventions of aggressive tumors. Methods A report of a 32-year-old woman with a 61 9 41 mm chromophobe renal cell carcinoma (RCC) successfully treated with laparoscopic transperitoneal hand-assisted nephrectomy during the 20th week of gestation is presented. Results The fetus was stable during the intervention; the postoperative period was uneventful; she had a normal vaginal delivery at term and gave birth to a healthy female
Z. Domja´n (&) A. S. Da´kay I. Buzoga´ny Department of Urology, Pe´terfy Sa´ndor Hospital, Pe´terfy Sa´ndor Str. 8-20, Budapest 1074, Hungary e-mail: [email protected] A. S. Da´kay e-mail: [email protected] I. Buzoga´ny e-mail: [email protected] E. Holman N. Borda´s Department of Urology, Semmelweis Hospital, Dr. Monszpart L. Str. 1, Kiskunhalas 6400, Hungary e-mail: [email protected] N. Borda´s e-mail: [email protected] K. Bahrehmand Department of Obstetrics and Gynecology, Pe´terfy Sa´ndor Hospital, Pe´terfy Sa´ndor Str. 8-20, Budapest 1074, Hungary e-mail: [email protected]
child. The patient remained tumor-free at her 34-month follow-up. Conclusion Although the pure laparoscopic interventions have become recognized in the treatment of RCC over the last decade, these methods have their limitations and dangers as well. The hand-assistance method makes the procedure faster and safer which is especially important during second or third trimester. Renal biopsy may play a specifically important role in predicting the malignant potential of a renal tumor, whereas postponement of this surgery until after delivery, may lead to the mother’s death. To our knowledge, this is the first report on hand-assisted laparoscopic nephrectomy in pregnancy. Keywords Renal cell carcinoma Hand-assisted laparoscopy Laparoscopic nephrectomy Renal biopsy Pregnancy
Introduction Renal cell carcinoma (RCC) is a rare tumor at childbearing age. The incidence is far below 5/100,000 cases per year [1]. Timing of operation is crucial, and loss of time may lead to fatal cancer-related consequences according to the literature [2]. Laparoscopic tumor nephrectomy seems to be an optimal choice in managing T1 renal tumors during any trimester. The benefits of laparoscopic surgery for the mother are well-known better convalescence, less wound problems, lower risk of thromboembolic events, and decreased fetal respiratory depression due to the reduction of postoperative narcotics administered for pain [3]. The debate of transperitoneal and retroperitoneal approach is ongoing—both methods have some technical limitations. Following is the explanation of the advantages and safety
123
Int Urol Nephrol
of hand-assisted laparoscopic (HAL) tumor nephrectomy in RCC during pregnancy which can be performed in any trimester.
Patients and methods A 32-year-old woman was assessed for hypertension at the 16th week of gestation of her second pregnancy. A renal ultrasonography revealed a 61 9 40 mm central mass in the left kidney. MRI described a tumor with sharp edges, impression of the renal pelvis, presumable renal cell carcinoma, but oncocytoma could not be excluded (Fig. 1). In order to get more information about the biological behavior and probable prognosis of the tumor, a renal biopsy was performed. The histological report of the first ultrasoundguided core biopsies (two biopsies, 20 mm renal tissue cylinders) made by a 18-gauge needle showed no malignancy. A second biopsy, 10 days later, revealed renal cell cancer, chromophobe type. MRI and chest X-ray was negative regarding distal metastases. Blood tests revealed no abnormalities and normal renal function. Preoperatively, the ultrasound examination showed a healthy fetus. At the 20th gestational week, a HAL radical tumor nephrectomy was performed preserving the adrenal gland. Procedure
10-mm ports were inserted, one for the camera at the midclavicular line at the level of the umbilicus, and the other laterally and distally to the first port for working instruments (Fig. 2). A surgical sponge and a bulldog clamp were inserted as well to facilitate the hand’s work. Pneumoperitoneum was created with 12 mmHg pressure. The extremely dilated left gonadal vein was ligated before hilar dissection. The operation lasted 1 h and 40 min, with blood loss less than 100 cc, and with no complications during the procedure. Removal of the specimen was through the handport. The postoperative period was uneventful, and the patient was discharged on the fourth day after the procedure.
Results The histology report verified chromophobe cell type renal cell carcinoma, Fuhrman grade II, pT1b. The remainder of the pregnancy was uncomplicated. She had a normal vaginal delivery at term, giving birth to a healthy female child. The patient was without tumor recurrence at her 34-month follow-up.
Discussion Cancer is the second most common cause of the mother’s death in pregnancy. This malignancy accounts for only
An 8-cm-long laparotomy was performed in the midline above the umbilicus to place the hand port (Dextrus, Ethicon Endo-Surgery LLC) into the abdominal wall. Two
Fig. 1 MRI of left central renal mass
123
Fig. 2 Schematic figure of the handport and trocar placement
Int Urol Nephrol
50 % of renal masses during pregnancy, while angiomyolipomas occur in 23 % [4], oncocytomas in 3–7 % [5], and the remaining percentages are of other aggressive tumor types occuring during the childbearing ages. Timing of surgery depends on the malignant potential of the renal masses. In case of benign lesions, surgery may be postponed until after delivery. Since the mother’s welfare is the primary concern, surgery should not be delayed with malignant tumors, especially renal cell cancer or sarcomatoid tumors. Two publications were found when aggressive tumors caused metastatic disease with fatal outcome due to late intervention [1, 2]. Time of surgery is influenced by the age of gravidity as well. The clinician’s primary responsibility is the mother, though management must take into account her wishes regarding the welfare of the fetus. The risk of spontaneous abortion is higher in first trimester; therefore, a detailed counseling is needed to inform the parents about the risks of operation and delayed procedure. Based on historical recommendations, it is best to perform operations during the second trimester. To avoid the danger of preterm labor in the third trimester, watchful waiting up until the 28th week is recommended, whereas afterward inducing term labor is a reasonable option when neonatal survival rates are over 90 % due to improvements in neonatal care [6, 7]. Minimal invasive solutions became widely used in pregnant patients as well as increasing experience and technical advances in laparoscopic surgery [8, 9]. According to novel literature in different fields of surgery, laparoscopy is markedly less stressful than open surgery as investigated by measurements of cytokines after the procedures [10, 11]. This may have a greater importance in the gestational period, as the immune system has tolerance for antigenic tissues, although manifested immune deficiencies have not been demonstrated [12]. The additional benefits of laparoscopy in pregnant patients include decreased respiratory depression due to reduced postoperative narcotics requirements, the lower risk of wound complications and incisional hernia, and decreased postoperative maternal hypoventilation. Technical advantages of this approach are responsible for lower rates of spontaneous abortion and preterm delivery, particularly avoiding uterine manipulations due to improved visualization. The Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) recommend that laparoscopic intervention can be performed in any trimester of pregnancy without any increased risk to the mother or fetus [9]. Increased abdominal pressure may lead to alteration of placental perfusion and must be kept below 15 mmHg according to SAGES’s advocation in order to prevent low cardiac output and a disturbing acid-based balance in the fetus [9]. This is the reason why Reedy and Holthausen have not found a difference in fetal outcomes between open and
laparoscopic nonobstetric surgery in their reviews of a large number of patients [3, 13]. Only a few case reports of laparoscopic tumor nephrectomy are available in literature, due to the rare occurrence of renal tumors during the gestational period. At first, the authors performed the transperitoneal approach [14, 15], while other physicians using the retroperitoneal route [16, 17] later published reports about its success. The transperitoneal method provides a useful larger working space in cases of an enlarged uterus. The retroperitoneal approach, on the other hand, makes a direct access to vessels without bowel manipulation and minimizes the uterine irritation [14, 17]. In the case of this patient, a safe and relatively timesparing procedure was carried out on a verified chromophobe cell carcinoma in the left kidney during her 20th week of pregnancy. Hand-assisted laparoscopy (HAL) has several advantages over the pure laparoscopical methods, especially in gravidity. In the study mentioned above, authors recommended an open placement of the first trocar because of complications due to Veress needle insertions after reviewing more than 2 million procedures [15]. Nonetheless, removal of the specimen at the end of the intervention needs a minilaparotomy, reducing the real value of pure laparoscopy. In the authors’ opinions, making an 8-cm-long laparotomy first insures a safe introduction into the abdominal cavity which is desirable in cases of an enlarged pregnant uterus (Fig. 3). Use of a hand in the abdomen may accelerate manipulations, thus shortening the time of increased abdominal pressure and anesthesia. HAL radical tumor nephrectomy renders the advantages of both transperitoneal laparoscopic and open procedures. The authors believe that HAL nephrectomy should be one of
Fig. 3 The patients abdominal scars at 38th weeks of pregnancy
123
Int Urol Nephrol
the most preferred methods of surgery during pregnancy, for it combines maximum safety with the advantages of minimal invasive techniques. Conflict of interest
None.
References 1. Schno¨ller TJ, Jentzmik F, Al Ghazal A et al (2011) Renal masses in pregnancy. Diagnostics and therapeutic management. Urol A 50(9):1064–1067 2. Bettez M, Carmel M, Temmar R et al (2011) Fatal fast-growing renal cell carcinoma during pregnancy. Obstet Gynecol Can 33(3):258–261 3. Reedy MB, Ka¨lle´n B, Kuehl TJ (1997) Laparoscopy during pregnancy: a study of five fetal outcome parameters with use of the Swedish Health Registry. Am J Obstet Gynecol 177:673–679 4. Siesling S, van Dijk JA, Visser O, Coeberg JW (2003) Working group of Netherlands Cancer Registry: trends in the incidence of, and mortality from cancer in the Netherlands in the period 1989–1998. Eur J Cancer 39:2521 5. Wentzel SW, Vermeulen LP (2012) Bilateral multifocal renal oncocytoma in pregnancy. Rare Tumors 4(4):e54 6. Oelsner G, Stockheim D, Soriano D et al (2003) Pregnancy outcome after laparoscopy or laparotomy in pregnancy. J Am Assoc Gynecol Laparosc 10:200–204 7. Gladman MA, MacDonald D, Webster JJ, Cook T, Williams G (2002) Renal cell carcinoma in pregnancy. J R Soc Med 95(4):199–201
123
8. O’Connor JP, Biyani CS, Taylor J et al (2004) Laparoscopic nephrectomy for renal-cell carcinoma during pregnancy. J Endourol 18:871–874 9. SAGES (2008) Guidelines for diagnosis, treatment, and use of laparoscopy for surgical problems during pregnancy. Surg Endosc 22:849–861 10. Wang SZ, Chen Y, Lin HY, Chen LW (2010) Comparison of surgical stress response to laparoscopic and open radical cystectomy. World J Urol 28(4):451–455 11. Veenhof AA, Sietses C, von Blomberg BM et al (2011) The surgical stress response and postoperative immune function after laparoscopic or conventional total mesorectal excision in rectal cancer: a randomized trial. Int J Colorectal Dis 26(1):53–59 12. Donegan WL (1983) Cancer and pregnancy. CA Cancer J Clin 33:194–214 13. Holthausen UH, Mettler L, Troidl H (1999) Pregnancy: a contraindication? World J Surg 23:856–862 14. O’Connor JP, Biyani CS, Taylor J, Agarwal V, Curley PJ, Browning AJ (2004) Laparoscopic nephrectomy for renal-cell carcinoma during pregnancy. J Endourol 18(9):871–874 15. Sainsbury DC, Dorkin TJ, MacPhail S, Soomro NA (2004) Laparoscopic radical nephrectomy in first-trimester pregnancy. Urology 64(1231):e7–e8 16. Van Basten JPA, Knipscheer B, De Kruif J (2006) Retroperitoneoscopic tumor nephrectomy during pregnancy. J Endourol 20(3):186–187 17. Stroup SP, Altamar HO, L’Esperance JO, Auge BK (2007) Retroperitoneoscopic radical nephrectomy for renal-cell carcinoma during twin pregnancy. J Endourol 21:735–737
UROLOGY - ORIGINAL PAPER
Hand-assisted laparoscopic radical nephrectomy in pregnancy Zsolt Domja´n • Endre Holman • Noe´mi Borda´s • Alexander Stephan Da´kay • Kiarash Bahrehmand Istva´n Buzoga´ny
•
Received: 7 March 2014 / Accepted: 21 April 2014 Ó Springer Science+Business Media Dordrecht 2014
Abstract Purpose To demonstrate the beneficial results of handassisted laparoscopic tumor nephrectomy in pregnancy and to emphasize the proper timing of such surgery for its crucial importance attempting to avoid fatal cancer-related outcomes as a result of late interventions of aggressive tumors. Methods A report of a 32-year-old woman with a 61 9 41 mm chromophobe renal cell carcinoma (RCC) successfully treated with laparoscopic transperitoneal hand-assisted nephrectomy during the 20th week of gestation is presented. Results The fetus was stable during the intervention; the postoperative period was uneventful; she had a normal vaginal delivery at term and gave birth to a healthy female
Z. Domja´n (&) A. S. Da´kay I. Buzoga´ny Department of Urology, Pe´terfy Sa´ndor Hospital, Pe´terfy Sa´ndor Str. 8-20, Budapest 1074, Hungary e-mail: [email protected] A. S. Da´kay e-mail: [email protected] I. Buzoga´ny e-mail: [email protected] E. Holman N. Borda´s Department of Urology, Semmelweis Hospital, Dr. Monszpart L. Str. 1, Kiskunhalas 6400, Hungary e-mail: [email protected] N. Borda´s e-mail: [email protected] K. Bahrehmand Department of Obstetrics and Gynecology, Pe´terfy Sa´ndor Hospital, Pe´terfy Sa´ndor Str. 8-20, Budapest 1074, Hungary e-mail: [email protected]
child. The patient remained tumor-free at her 34-month follow-up. Conclusion Although the pure laparoscopic interventions have become recognized in the treatment of RCC over the last decade, these methods have their limitations and dangers as well. The hand-assistance method makes the procedure faster and safer which is especially important during second or third trimester. Renal biopsy may play a specifically important role in predicting the malignant potential of a renal tumor, whereas postponement of this surgery until after delivery, may lead to the mother’s death. To our knowledge, this is the first report on hand-assisted laparoscopic nephrectomy in pregnancy. Keywords Renal cell carcinoma Hand-assisted laparoscopy Laparoscopic nephrectomy Renal biopsy Pregnancy
Introduction Renal cell carcinoma (RCC) is a rare tumor at childbearing age. The incidence is far below 5/100,000 cases per year [1]. Timing of operation is crucial, and loss of time may lead to fatal cancer-related consequences according to the literature [2]. Laparoscopic tumor nephrectomy seems to be an optimal choice in managing T1 renal tumors during any trimester. The benefits of laparoscopic surgery for the mother are well-known better convalescence, less wound problems, lower risk of thromboembolic events, and decreased fetal respiratory depression due to the reduction of postoperative narcotics administered for pain [3]. The debate of transperitoneal and retroperitoneal approach is ongoing—both methods have some technical limitations. Following is the explanation of the advantages and safety
123
Int Urol Nephrol
of hand-assisted laparoscopic (HAL) tumor nephrectomy in RCC during pregnancy which can be performed in any trimester.
Patients and methods A 32-year-old woman was assessed for hypertension at the 16th week of gestation of her second pregnancy. A renal ultrasonography revealed a 61 9 40 mm central mass in the left kidney. MRI described a tumor with sharp edges, impression of the renal pelvis, presumable renal cell carcinoma, but oncocytoma could not be excluded (Fig. 1). In order to get more information about the biological behavior and probable prognosis of the tumor, a renal biopsy was performed. The histological report of the first ultrasoundguided core biopsies (two biopsies, 20 mm renal tissue cylinders) made by a 18-gauge needle showed no malignancy. A second biopsy, 10 days later, revealed renal cell cancer, chromophobe type. MRI and chest X-ray was negative regarding distal metastases. Blood tests revealed no abnormalities and normal renal function. Preoperatively, the ultrasound examination showed a healthy fetus. At the 20th gestational week, a HAL radical tumor nephrectomy was performed preserving the adrenal gland. Procedure
10-mm ports were inserted, one for the camera at the midclavicular line at the level of the umbilicus, and the other laterally and distally to the first port for working instruments (Fig. 2). A surgical sponge and a bulldog clamp were inserted as well to facilitate the hand’s work. Pneumoperitoneum was created with 12 mmHg pressure. The extremely dilated left gonadal vein was ligated before hilar dissection. The operation lasted 1 h and 40 min, with blood loss less than 100 cc, and with no complications during the procedure. Removal of the specimen was through the handport. The postoperative period was uneventful, and the patient was discharged on the fourth day after the procedure.
Results The histology report verified chromophobe cell type renal cell carcinoma, Fuhrman grade II, pT1b. The remainder of the pregnancy was uncomplicated. She had a normal vaginal delivery at term, giving birth to a healthy female child. The patient was without tumor recurrence at her 34-month follow-up.
Discussion Cancer is the second most common cause of the mother’s death in pregnancy. This malignancy accounts for only
An 8-cm-long laparotomy was performed in the midline above the umbilicus to place the hand port (Dextrus, Ethicon Endo-Surgery LLC) into the abdominal wall. Two
Fig. 1 MRI of left central renal mass
123
Fig. 2 Schematic figure of the handport and trocar placement
Int Urol Nephrol
50 % of renal masses during pregnancy, while angiomyolipomas occur in 23 % [4], oncocytomas in 3–7 % [5], and the remaining percentages are of other aggressive tumor types occuring during the childbearing ages. Timing of surgery depends on the malignant potential of the renal masses. In case of benign lesions, surgery may be postponed until after delivery. Since the mother’s welfare is the primary concern, surgery should not be delayed with malignant tumors, especially renal cell cancer or sarcomatoid tumors. Two publications were found when aggressive tumors caused metastatic disease with fatal outcome due to late intervention [1, 2]. Time of surgery is influenced by the age of gravidity as well. The clinician’s primary responsibility is the mother, though management must take into account her wishes regarding the welfare of the fetus. The risk of spontaneous abortion is higher in first trimester; therefore, a detailed counseling is needed to inform the parents about the risks of operation and delayed procedure. Based on historical recommendations, it is best to perform operations during the second trimester. To avoid the danger of preterm labor in the third trimester, watchful waiting up until the 28th week is recommended, whereas afterward inducing term labor is a reasonable option when neonatal survival rates are over 90 % due to improvements in neonatal care [6, 7]. Minimal invasive solutions became widely used in pregnant patients as well as increasing experience and technical advances in laparoscopic surgery [8, 9]. According to novel literature in different fields of surgery, laparoscopy is markedly less stressful than open surgery as investigated by measurements of cytokines after the procedures [10, 11]. This may have a greater importance in the gestational period, as the immune system has tolerance for antigenic tissues, although manifested immune deficiencies have not been demonstrated [12]. The additional benefits of laparoscopy in pregnant patients include decreased respiratory depression due to reduced postoperative narcotics requirements, the lower risk of wound complications and incisional hernia, and decreased postoperative maternal hypoventilation. Technical advantages of this approach are responsible for lower rates of spontaneous abortion and preterm delivery, particularly avoiding uterine manipulations due to improved visualization. The Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) recommend that laparoscopic intervention can be performed in any trimester of pregnancy without any increased risk to the mother or fetus [9]. Increased abdominal pressure may lead to alteration of placental perfusion and must be kept below 15 mmHg according to SAGES’s advocation in order to prevent low cardiac output and a disturbing acid-based balance in the fetus [9]. This is the reason why Reedy and Holthausen have not found a difference in fetal outcomes between open and
laparoscopic nonobstetric surgery in their reviews of a large number of patients [3, 13]. Only a few case reports of laparoscopic tumor nephrectomy are available in literature, due to the rare occurrence of renal tumors during the gestational period. At first, the authors performed the transperitoneal approach [14, 15], while other physicians using the retroperitoneal route [16, 17] later published reports about its success. The transperitoneal method provides a useful larger working space in cases of an enlarged uterus. The retroperitoneal approach, on the other hand, makes a direct access to vessels without bowel manipulation and minimizes the uterine irritation [14, 17]. In the case of this patient, a safe and relatively timesparing procedure was carried out on a verified chromophobe cell carcinoma in the left kidney during her 20th week of pregnancy. Hand-assisted laparoscopy (HAL) has several advantages over the pure laparoscopical methods, especially in gravidity. In the study mentioned above, authors recommended an open placement of the first trocar because of complications due to Veress needle insertions after reviewing more than 2 million procedures [15]. Nonetheless, removal of the specimen at the end of the intervention needs a minilaparotomy, reducing the real value of pure laparoscopy. In the authors’ opinions, making an 8-cm-long laparotomy first insures a safe introduction into the abdominal cavity which is desirable in cases of an enlarged pregnant uterus (Fig. 3). Use of a hand in the abdomen may accelerate manipulations, thus shortening the time of increased abdominal pressure and anesthesia. HAL radical tumor nephrectomy renders the advantages of both transperitoneal laparoscopic and open procedures. The authors believe that HAL nephrectomy should be one of
Fig. 3 The patients abdominal scars at 38th weeks of pregnancy
123
Int Urol Nephrol
the most preferred methods of surgery during pregnancy, for it combines maximum safety with the advantages of minimal invasive techniques. Conflict of interest
None.
References 1. Schno¨ller TJ, Jentzmik F, Al Ghazal A et al (2011) Renal masses in pregnancy. Diagnostics and therapeutic management. Urol A 50(9):1064–1067 2. Bettez M, Carmel M, Temmar R et al (2011) Fatal fast-growing renal cell carcinoma during pregnancy. Obstet Gynecol Can 33(3):258–261 3. Reedy MB, Ka¨lle´n B, Kuehl TJ (1997) Laparoscopy during pregnancy: a study of five fetal outcome parameters with use of the Swedish Health Registry. Am J Obstet Gynecol 177:673–679 4. Siesling S, van Dijk JA, Visser O, Coeberg JW (2003) Working group of Netherlands Cancer Registry: trends in the incidence of, and mortality from cancer in the Netherlands in the period 1989–1998. Eur J Cancer 39:2521 5. Wentzel SW, Vermeulen LP (2012) Bilateral multifocal renal oncocytoma in pregnancy. Rare Tumors 4(4):e54 6. Oelsner G, Stockheim D, Soriano D et al (2003) Pregnancy outcome after laparoscopy or laparotomy in pregnancy. J Am Assoc Gynecol Laparosc 10:200–204 7. Gladman MA, MacDonald D, Webster JJ, Cook T, Williams G (2002) Renal cell carcinoma in pregnancy. J R Soc Med 95(4):199–201
123
8. O’Connor JP, Biyani CS, Taylor J et al (2004) Laparoscopic nephrectomy for renal-cell carcinoma during pregnancy. J Endourol 18:871–874 9. SAGES (2008) Guidelines for diagnosis, treatment, and use of laparoscopy for surgical problems during pregnancy. Surg Endosc 22:849–861 10. Wang SZ, Chen Y, Lin HY, Chen LW (2010) Comparison of surgical stress response to laparoscopic and open radical cystectomy. World J Urol 28(4):451–455 11. Veenhof AA, Sietses C, von Blomberg BM et al (2011) The surgical stress response and postoperative immune function after laparoscopic or conventional total mesorectal excision in rectal cancer: a randomized trial. Int J Colorectal Dis 26(1):53–59 12. Donegan WL (1983) Cancer and pregnancy. CA Cancer J Clin 33:194–214 13. Holthausen UH, Mettler L, Troidl H (1999) Pregnancy: a contraindication? World J Surg 23:856–862 14. O’Connor JP, Biyani CS, Taylor J, Agarwal V, Curley PJ, Browning AJ (2004) Laparoscopic nephrectomy for renal-cell carcinoma during pregnancy. J Endourol 18(9):871–874 15. Sainsbury DC, Dorkin TJ, MacPhail S, Soomro NA (2004) Laparoscopic radical nephrectomy in first-trimester pregnancy. Urology 64(1231):e7–e8 16. Van Basten JPA, Knipscheer B, De Kruif J (2006) Retroperitoneoscopic tumor nephrectomy during pregnancy. J Endourol 20(3):186–187 17. Stroup SP, Altamar HO, L’Esperance JO, Auge BK (2007) Retroperitoneoscopic radical nephrectomy for renal-cell carcinoma during twin pregnancy. J Endourol 21:735–737
