Laparoscopic Anatrophic Nephrolithotomy a Feasible Option in Staghorn Calculi

Management of stag horn calculi is still a big challenge for urologist dedicated to stone treatment, even with the recent advances in endourology it is difficult to obtain a stone free rate of 100% with a single procedure. Endourological techniques have revolutionized the treatment of urinary stones to the point that open surgery has become anachronistic [1]. Laparoscopic surgery could be considered in selected patients like those who has a big stone burden, associated renal malformations, or in those who endourological techniques has previously failed or will require multiple endourology procedures [2-4]. Stag horn calculi are defined as those stones that fill up the majority of renal collecting system, occupying renal pelvis and branching out into most calyces [3]. In the present study we describe our results, surgical technique and we made a literature research and review, with the purpose to compare ours results to previous case series already published in PubMed.


Introduction
Management of stag horn calculi is still a big challenge for urologist dedicated to stone treatment, even with the recent advances in endourology it is difficult to obtain a stone free rate of 100% with a single procedure. Endourological techniques have revolutionized the treatment of urinary stones to the point that open surgery has become anachronistic [1]. Laparoscopic surgery could be considered in selected patients like those who has a big stone burden, associated renal malformations, or in those who endourological techniques has previously failed or will require multiple endourology procedures [2][3][4]. Stag horn calculi are defined as those stones that fill up the majority of renal collecting system, occupying renal pelvis and branching out into most calyces [3]. In the present study we describe our results, surgical technique and we made a literature research and review, with the purpose to compare ours results to previous case series already published in PubMed.

Patients and Methods
We included all patients with a stag horn calculi diagnosis and undergo laparoscopic anatrophic nephrolithotomy (LAN) between January 2014 to January 2015 at Hospital Civil Fray Antonio Alcalde. In this study we reported our initial experience with this procedure, patient characteristics that were evaluated include demographic data (age) stone features (size, volume, density, laterality), intra operative variables (surgical time, blood loss, transfusion rate, complications), post operative variables (hospitalization days, complications, transfusion and stone free rate). It is worth highlighting that all procedures were done by the same surgeon and all patients signed informed consent before surgery, were undergone to preoperative anesthesia evaluation and to a CT scan with non-contrast with the purpose to evaluate stone size and anatomical features.
All patients were admitted on the day before surgery and every one received prophylaxis with intravenous antibiotics [1] hour before surgery. In the postoperative period patients were subjected to a non-contrast low dose CT scan to confirm stone free rate (defined as no fragments of >4mm) [5]. In all patients Foley catheter was removed before the discharge, Jackson-Pratt type drainage was removed when the 24 hour output was less than 50ml and the double J catheter was removed two weeks after procedure with local anesthesia if the patients was 100% Stone free rate. We performed a research for the serial cases publish in the data base PubMed texting the words "Laparoscopic" AND "Anatrophic AND "Nephrolithotomy" with the filter in article type selecting Journal Article, we excluded those articles with only one patient (case reports) and the surgeries performed with the robot.

Laparoscopic technique
All procedures were performed under general anesthesia and a double J catheter was placed in all cases at the beginning of surgery, thereafter every patient was placed in lateral decubitus position. For left side we used 4 trocars, but if the procedure is on the right side we added a 5mm trocar with the purpose of liver retraction. The first trocar placed is a 10mm trocar, that is used for the 30 degrees lens, and anatomically it is placed in the pararectal line 3-4cm above the navel, the second trocar is a 10mm diameter and it is inserted 8-9cm to the right of the first trocar, the third trocar is of 5mm and placed to the left of the first trocar about 8-9cm so these three trocars form an imaginary triangle. The fourth trocar, occasionally, is placed on the axillary posterior line as a support, for renal retraction and if the procedure is on the right side, an additional 5mm trocar is placed to retract the liver. A transperitoneal approach was performed in all patients and the first step once trocars are placed is to fall out told's fascia, with mobilization of colon and other structures such as duodenum and liver if we are on the right side. Dissection was continued until the renal hilum was exposed so can be adequately prepared to be clamped. Thereafter the dissection of the perirenal fat of the anterior and posterior segment was done with the purpose of discover the renal capsule and could have an adequate exposure of both sides of the kidney and renal hilum. The next step was to clamp the renal artery (only) with a bulldog clamp Figure 1 and to increase the pneumoperitoneum to 20mmHg, to reduce the bleeding with by an increase peritoneal pressure (the rest of the surgery worked with 14mmHg).   Once intra abdominal pressure increase to 20mmHg a laparoscopic scalpel (blade number 11) was prepared to perform the incision in the renal parenchyma and a 3-4cm renal incision was performed trying to identify the avascular line of Brodel, which is difficult to identify because of its irregularities in its path [6]. Once the collector system is opened and the stone is exposed, an Alice clamp is introduced to release the stone, taking care of remove the stone in one piece (Figure 2). Thereafter collector system is then explored with a 30-degree lens for residual stone. As a final step prior to removal of the bulldog clamp, renal parenchyma is sutured with a 2-0 polyglactin reinforced with a hem-o-lock (Figure 3), after completing the suture, the bulldog clamp was removed with the purpose of evaluate presence of bleeding, there was some bleeding detected, additional "X" suture points and Gelfoam were placed at the site of renal parenchyma incision (Figure 4). It is very important to consider that warm ischemia should be less than 30 minutes because previous reports, have postulated that a prolonged ischemia causes greater renal damage [6]. Finally Jackson-Pratt type drainage was left in place.

Results
A total of eight patients were undergo to laparoscopic anatrophic nephrolithotomy, mean patients age were 42.1 years, stone diameter was 52.6mm, 5 stones (62.5%) were found in left topography and 3 stones (37.5%) were in the right topography, mean surgical time 127.5 minutes [7,8], warm ischemia time 29.5 minutes, blood loss average 218.7ml, transfusion rate 0%, 2 complications (25%), we decided to perform a nephrectomy in a patient due to prolonged ischemia and one patient was discharge with no complications but he returns to the emergency room with gross hematuria [9] days postoperatively, which did not yield to medical treatment also the non-availability to performed an angiography + embolization (high suspicion of pseudoaneurisma). Stone free rate was 75%, length in hospital were 3.5 days. The same surgeon performed all the surgeries (Table 1). In our research in PubMed we obtain 14 results of those we only found 4 serial cases that performed LAN: Simforoosh [5,6] number of patients 24, mean surgical time 202 minutes, ischemia 30 minutes, stone burden 61 mm, stone free rate 88%, no complications; Zhou [8] number of patients 11, mean surgical time 139, ischemia 31 minutes; stone burden 52 mm, stone free rate 90.9%, complications 3 urinary leakage.

Discussion
We know that stag horn calculi is a real challenge for all urologists that are dedicated to renal stone management, the main purpose treatment is to obtain a complete clearance (stone free rate of 100%), because they are related to infection an incomplete removal will produce recurrence [10,11], staghorn renal calculi can destroy not only renal function, but also general health. American Urological Association guidelines 2016 state that the first line treatment for stag horn calculi is percutaneous nephrolithotomy [12] (PCNL) because in respect to open surgery, PCNL has demonstrated comparable stone-free rates but it offers lower morbidity evidenced by decreased intra operative and postoperative complications, decreased length of hospital stay, earlier return to work, and much smaller surgical incision [13][14][15].
Multiple treatments have been proposed for stag horn calculi in an older trail comparing PNCL in combination with shock wave lithotripsy (SWL) and SWL as monotherapy, Meretyk et al. [16] found a better free stone rates with combination therapy, and the rate of sepsis was higher in monotheraphy. In our study we found that in the index data they are only 5 studies (including ours) with a total of 61 patients undergo LAN, in this data the who has more experience is Simforoosh et al. [5] with 24 patients; the mean surgical time in our study was 127.5 minutes, compared with the mean time in the other studies 168 minutes (range 139-202 minutes). The highest Stone rate was achieved by Zhou et al. [8] with a 90.9%, where in a low range with 75% this may be due some studies use alternatives options and do not performed CT scan for Stone free rate evaluation.
There's big laparoscopic series like Qin who performed 75 cases, in patients with a large stone but the surgery they apply was pyelolithotomy with a 92% stone free rate, but with a high rate of complications [13]. It's no easy to get a high free stone rate King et al. [17] performed seven robot-assisted anatrophic nephrolithotomy achieve only 27%. Making a comparison between LAN and open anatrophic nephrolithotomy (OAN) in stone free rate OAN reported 71% [16], the rate obtained with LAN is 80.4% (average of 5 studies). Similar results in stone free rate but as we can see in this study decreased length of hospital stay (3.5 days), less pain, less transfusion rate, make LAN a feasible option to treat stag horn calculi in experimented laparoscopic centers. The laparoscopic approach is a minimally invasive alternative to endourologic treatment in some special conditions for example: Stag horn calculi + retrocaval ureter, stones surgery that need an extra ablative and reconstructive therapy (like pyeloplasty [15,18], patient do not accept multiple procedures with PCNL or if the kidney had unusually complex anatomy [19], multiple failed endourological procedures, etc. Many treatments have been proposed to treat stag horn calculi, but there no one that achieve a 100% stone free rate, all procedures have complications, so patient and doctor will have to discuss all available options and choose the best option for each case [20][21][22].

Conclusion
LAN could be feasible option, in those patients who are no candidates to PCNL or other endourologic procedures, achieving a reasonable stone free rate with a single procedure [23]. It should be noted that LAN is an advanced laparoscopic procedure and should be performed by expert laparoscopists. Furthermore it is necessary a randomize controlled trial comparing percutaneous nephrolithotomy and laparoscopic anatrophic nephrolithotomy to evaluate real advantages and disadvantages.