Urolithiasis (2015) 43:5–12 DOI 10.1007/s00240-014-0736-2
INVITED REVIEW
Ureteropelvic obstruction and renal stones: etiology and treatment Andreas Skolarikos · Andreas Dellis · Thomas Knoll
Received: 13 October 2014 / Accepted: 23 October 2014 / Published online: 2 November 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract The simultaneous surgical management of ureteropelvic junction obstruction (UPJO) with concomitant renal stones has evolved the last 20 years; hence, the ideal minimally invasive technique is still controversial. Laparoscopic and robot-assisted laparoscopic operations allow precise surgical maneuvers and were thought to simplify the reconstruction steps of the procedure, especially in the treatment of complex cases with large stones. The aim of this study was to summarize the available perioperative and functional outcomes of minimally invasive available techniques. A non-systematic review of the literature was performed using a free-text protocol in the MEDLINE database. The terms used were “ureteropelvic junction obstruction,” “renal calculi” and “renal stones.” Furthermore, other significant relevant studies cited in the reference lists of the selected papers were also evaluated in the structure of this review. Currently, available evidence suggests that both laparoscopic and robotic-assisted techniques offer excellent surgical solutions in the field of UPJO reconstruction and renal stones removal. In the hands of experienced surgeons, laparoscopic and robotic pyeloplasty with concomitant stone removal is a safe procedure with high stone-free rates and UPJ patency. Minimally invasive pyeloplasty should constitute the first choice of treatment for concomitant renal stones and ureteropelvic junction obstruction.
Keywords Ureteropelvic junction obstruction · Renal stones · Minimally invasive pyeloplasty
Introduction Patients with primary ureteropelvic junction obstruction (UPJO) have up to 16–30 % chance of concomitant renal stones [1]. Several questions need to be addressed in these patients [2]. What is the role of UPJO in stone formation? What other predisposing factors to stone formation may be present in these patients? Do calculi contribute to the development of UPJO? How does the presence of stone influence management of UPJO and vice versa? Studies published on the combination of UPJO and renal stones represent small retrospective non-comparative series. As a consequence, providing definitive answers to these questions may be problematic. In this study, we performed a non-systematic and critical review of the literature with the aim to give proper and well-documented answers to the aforementioned questions, as well as to summarize the available relevant perioperative and functional results of minimally invasive techniques for pyeloplasty and renal stone removal.
Evidence acquisition A. Skolarikos · A. Dellis 2nd Department of Urology, Sismanoglio Hospital, Athens Medical School, Athens, Greece T. Knoll (*) Department of Urology, Klinikum Sindelfingen‑Böblingen, University of Tübingen, Sindelfingen, Germany e-mail: t.knoll@klinikverbund‑suedwest.de
We performed a non-systematic review of the literature using the MEDLINE database. Our MEDLINE search included a free-text protocol using the terms “ureteropelvic junction obstruction,” “renal calculi” and ‘‘renal stones’’ across the title and abstract field of the study records. Studies were categorized as performing laparoscopic or roboticassisted pyeloplasty and renal stone removal. Furthermore,
13
6
other significant relevant studies cited in the reference lists of the selected papers were also evaluated in the structure of this review. The following limits were used: English language; humans; publication date from 1997. Two authors (A.S. and A.D.) reviewed all the retrieved abstracts and finally selected the suitable for review papers. Other significant studies cited in the reference lists of the selected papers were also evaluated.
Evidence synthesis Lithogenesis: ureteropelvic junction obstruction Calculus formation may be predisposed in patients with UPJO due to urinary stasis and infection. Obstruction of the renal collecting system, with resultant urinary stasis and delayed washout of crystalline aggregates, promotes the process of nucleation, crystal growth, aggregation and finally stone formation. Supportive to the above pathophysiology is the fact that the recurrence of stones after the correction of UPJO is very low [3–5]. Apart from urinary stasis, metabolic abnormalities may also contribute in renal calculus formation in UPJO patients. Several facts are in favor of this theory. The majority of patients with a documented UPJO do not have renal calculi. Chemical composition of renal stones includes almost all type of stones. The incidence of metabolic abnormalities in patients with UPJO and stones, in the absence of infection or struvite calculi, was found to reach up to 76 %. The incidence increases to 87 % among patients with recurrent calculi. Up to 53 % of recurrent calculi may occur in the contralateral kidney [6–10]. Stone recurrence rate is significantly lower in patients who underwent pyeloplasty with medical treatment directed at the metabolic abnormality in comparison with patients who underwent pyeloplasty without treatment for the metabolic abnormality [11, 12]. Thus, although patients with UPJO alone may be at increased risk of stone formation, this risk is greatly enhanced if the patient already produces lithogenic urine. Hence, once must consider that even after successful treatment for UPJO with endopyelotomy or surgery, these patients may still be at risk of recurrent stone disease and treatable metabolic risk factors should be evaluated and treated [13]. The cause of primary UPJO is either intrinsic, representing a region of dysfunctional smooth muscle and excessive collagen deposition, or extrinsic including crossing aberrant blood vessels and constricting fibrous tissue bands, inflammatory diseases and malignancies [2]. No formal ultrastructural studies have examined the musculature of the UPJO in the presence of simultaneous calculus formation. In the future, such studies should differentiate the classic histologic finding of “congenital” obstruction from a true reactive stricture, resulting
13
Urolithiasis (2015) 43:5–12
from presumed pressure necrosis or inflammation from the stone. The high incidence of renal calculi associated with UPJO in the adult population may reflect an intimate and at times, causal association. A stone at the presence of UPJO may worsen the prognosis by increasing the amount of cicatrization in the ureteral wall [14]. Some patients with lithogenic urine may be predisposed toward intramural crystal formation within the UPJ, resulting in exuberant scarring [15]. An impacted UPJ stone may lead to considerable edema and friability contributing to the UPJO [16]. Finally, the presence of a stone at the UPJ may worsen the degree of obstruction and potentially exacerbate an already compromised renal unit [2, 15]. Once a diagnosis of UPJO and calculi has been determined, the urologist must decide among several treatment options. Cumulative data for the pediatric and adult populations suggest that the majority (up to 68 and 55 %, respectively) will have recurrent renal lithiasis when treated by observation alone. Active treatment is consequently recommended [8, 9]. Surgical techniques: endopyelotomy Occasionally, especially when the stone sits directly at the UPJ, it can be difficult to discern whether or not the UPJ is obstructed primarily or secondarily, from an impacted stone with edema. In this situation, it is best to first treat the stone percutaneously, leave a nephrostomy tube in place albeit well away from the UPJ, wait 2 weeks for resolution of the edema and then assess the drainage of the renal collecting system. This can be done using a DTPA or MAG-3 renal scan with frusemide washout, or if the nephrostomy tube has been left in place with a Whitaker test [1, 17, 18]. However, the literature is devoid of series of patients treated in such a manner [2]. Prior to deciding the best invasive treatment option for concomitant UPJO and renal calculi, urologists should take into consideration several issues regarding the success rate of UPJO therapies per se. Open pyeloplasty achieves very good (90–100 % success) results, endopyelotomy (EP) fails to match these results by 15–20 % and minimal access laparoscopic or robotic pyeloplasty produces results that are at least as good as those of open surgery but with the advantages of a minimal access approach [19]. Long-term success rates after both endopyelotomy and pyeloplasty are worse than previously reported. The estimated 3-, 5- and 10-year recurrence-free survival rates for endopyelotomy were 63, 55 and 41 %, respectively, compared with 85, 80 and 75 % for pyeloplasty (p 40 (good) 25–40 (moderate)
INVITED REVIEW
Ureteropelvic obstruction and renal stones: etiology and treatment Andreas Skolarikos · Andreas Dellis · Thomas Knoll
Received: 13 October 2014 / Accepted: 23 October 2014 / Published online: 2 November 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract The simultaneous surgical management of ureteropelvic junction obstruction (UPJO) with concomitant renal stones has evolved the last 20 years; hence, the ideal minimally invasive technique is still controversial. Laparoscopic and robot-assisted laparoscopic operations allow precise surgical maneuvers and were thought to simplify the reconstruction steps of the procedure, especially in the treatment of complex cases with large stones. The aim of this study was to summarize the available perioperative and functional outcomes of minimally invasive available techniques. A non-systematic review of the literature was performed using a free-text protocol in the MEDLINE database. The terms used were “ureteropelvic junction obstruction,” “renal calculi” and “renal stones.” Furthermore, other significant relevant studies cited in the reference lists of the selected papers were also evaluated in the structure of this review. Currently, available evidence suggests that both laparoscopic and robotic-assisted techniques offer excellent surgical solutions in the field of UPJO reconstruction and renal stones removal. In the hands of experienced surgeons, laparoscopic and robotic pyeloplasty with concomitant stone removal is a safe procedure with high stone-free rates and UPJ patency. Minimally invasive pyeloplasty should constitute the first choice of treatment for concomitant renal stones and ureteropelvic junction obstruction.
Keywords Ureteropelvic junction obstruction · Renal stones · Minimally invasive pyeloplasty
Introduction Patients with primary ureteropelvic junction obstruction (UPJO) have up to 16–30 % chance of concomitant renal stones [1]. Several questions need to be addressed in these patients [2]. What is the role of UPJO in stone formation? What other predisposing factors to stone formation may be present in these patients? Do calculi contribute to the development of UPJO? How does the presence of stone influence management of UPJO and vice versa? Studies published on the combination of UPJO and renal stones represent small retrospective non-comparative series. As a consequence, providing definitive answers to these questions may be problematic. In this study, we performed a non-systematic and critical review of the literature with the aim to give proper and well-documented answers to the aforementioned questions, as well as to summarize the available relevant perioperative and functional results of minimally invasive techniques for pyeloplasty and renal stone removal.
Evidence acquisition A. Skolarikos · A. Dellis 2nd Department of Urology, Sismanoglio Hospital, Athens Medical School, Athens, Greece T. Knoll (*) Department of Urology, Klinikum Sindelfingen‑Böblingen, University of Tübingen, Sindelfingen, Germany e-mail: t.knoll@klinikverbund‑suedwest.de
We performed a non-systematic review of the literature using the MEDLINE database. Our MEDLINE search included a free-text protocol using the terms “ureteropelvic junction obstruction,” “renal calculi” and ‘‘renal stones’’ across the title and abstract field of the study records. Studies were categorized as performing laparoscopic or roboticassisted pyeloplasty and renal stone removal. Furthermore,
13
6
other significant relevant studies cited in the reference lists of the selected papers were also evaluated in the structure of this review. The following limits were used: English language; humans; publication date from 1997. Two authors (A.S. and A.D.) reviewed all the retrieved abstracts and finally selected the suitable for review papers. Other significant studies cited in the reference lists of the selected papers were also evaluated.
Evidence synthesis Lithogenesis: ureteropelvic junction obstruction Calculus formation may be predisposed in patients with UPJO due to urinary stasis and infection. Obstruction of the renal collecting system, with resultant urinary stasis and delayed washout of crystalline aggregates, promotes the process of nucleation, crystal growth, aggregation and finally stone formation. Supportive to the above pathophysiology is the fact that the recurrence of stones after the correction of UPJO is very low [3–5]. Apart from urinary stasis, metabolic abnormalities may also contribute in renal calculus formation in UPJO patients. Several facts are in favor of this theory. The majority of patients with a documented UPJO do not have renal calculi. Chemical composition of renal stones includes almost all type of stones. The incidence of metabolic abnormalities in patients with UPJO and stones, in the absence of infection or struvite calculi, was found to reach up to 76 %. The incidence increases to 87 % among patients with recurrent calculi. Up to 53 % of recurrent calculi may occur in the contralateral kidney [6–10]. Stone recurrence rate is significantly lower in patients who underwent pyeloplasty with medical treatment directed at the metabolic abnormality in comparison with patients who underwent pyeloplasty without treatment for the metabolic abnormality [11, 12]. Thus, although patients with UPJO alone may be at increased risk of stone formation, this risk is greatly enhanced if the patient already produces lithogenic urine. Hence, once must consider that even after successful treatment for UPJO with endopyelotomy or surgery, these patients may still be at risk of recurrent stone disease and treatable metabolic risk factors should be evaluated and treated [13]. The cause of primary UPJO is either intrinsic, representing a region of dysfunctional smooth muscle and excessive collagen deposition, or extrinsic including crossing aberrant blood vessels and constricting fibrous tissue bands, inflammatory diseases and malignancies [2]. No formal ultrastructural studies have examined the musculature of the UPJO in the presence of simultaneous calculus formation. In the future, such studies should differentiate the classic histologic finding of “congenital” obstruction from a true reactive stricture, resulting
13
Urolithiasis (2015) 43:5–12
from presumed pressure necrosis or inflammation from the stone. The high incidence of renal calculi associated with UPJO in the adult population may reflect an intimate and at times, causal association. A stone at the presence of UPJO may worsen the prognosis by increasing the amount of cicatrization in the ureteral wall [14]. Some patients with lithogenic urine may be predisposed toward intramural crystal formation within the UPJ, resulting in exuberant scarring [15]. An impacted UPJ stone may lead to considerable edema and friability contributing to the UPJO [16]. Finally, the presence of a stone at the UPJ may worsen the degree of obstruction and potentially exacerbate an already compromised renal unit [2, 15]. Once a diagnosis of UPJO and calculi has been determined, the urologist must decide among several treatment options. Cumulative data for the pediatric and adult populations suggest that the majority (up to 68 and 55 %, respectively) will have recurrent renal lithiasis when treated by observation alone. Active treatment is consequently recommended [8, 9]. Surgical techniques: endopyelotomy Occasionally, especially when the stone sits directly at the UPJ, it can be difficult to discern whether or not the UPJ is obstructed primarily or secondarily, from an impacted stone with edema. In this situation, it is best to first treat the stone percutaneously, leave a nephrostomy tube in place albeit well away from the UPJ, wait 2 weeks for resolution of the edema and then assess the drainage of the renal collecting system. This can be done using a DTPA or MAG-3 renal scan with frusemide washout, or if the nephrostomy tube has been left in place with a Whitaker test [1, 17, 18]. However, the literature is devoid of series of patients treated in such a manner [2]. Prior to deciding the best invasive treatment option for concomitant UPJO and renal calculi, urologists should take into consideration several issues regarding the success rate of UPJO therapies per se. Open pyeloplasty achieves very good (90–100 % success) results, endopyelotomy (EP) fails to match these results by 15–20 % and minimal access laparoscopic or robotic pyeloplasty produces results that are at least as good as those of open surgery but with the advantages of a minimal access approach [19]. Long-term success rates after both endopyelotomy and pyeloplasty are worse than previously reported. The estimated 3-, 5- and 10-year recurrence-free survival rates for endopyelotomy were 63, 55 and 41 %, respectively, compared with 85, 80 and 75 % for pyeloplasty (p 40 (good) 25–40 (moderate)
