Published online Nov 30, 2016.
https://doi.org/10.4111/icu.2016.57.S2.S130
Robotic assisted adrenalectomy: Is it ready for prime time?
Abstract
Adrenal surgery is undergoing continuous evolution and minimally invasive surgery is increasingly being used for the surgical management of adrenal masses. With robotic-assisted surgery being a widely accepted surgical treatment for many urological conditions such as prostate carcinoma and renal cell carcinoma, the use of the robot has been expanded to include robotic-assisted adrenalectomy, offering an alternative minimally invasive platform for adrenal surgery. We performed a literature review on robotic-assisted adrenalectomy, reviewing the current surgical techniques and perioperative outcomes.
INTRODUCTION
Adrenalectomy is generally performed for both benign and malignant indications. Prior to the first description of laparoscopic adrenalectomy by Gagner et al. [1] in 1992, adrenalectomy was traditionally performed via the open approach. In 1999, Piazza et al. [2] and Hubens et al. [3] described the first robotic assisted adrenalectomy using the AESOP 2000, a commercially available robotic platform in Europe at that time.
The war between man (conventional laparoscopy) and the robot has been waging over the last decade with the introduction of the da Vinci robotic system (Intuitive Surgical, Sunnyvale, CA, USA). Robots are seemingly emerging victorious in the frontiers of prostatectomy [4] and partial nephrectomy [5] and are beginning to make major headways along the frontlines of radical cystectomy [6] with intracorporeal urinary diversion and nephroureterectomy [7]. Along the battlefronts of extirpative surgeries like radical nephrectomy where the benefits of the robot is less pronounced, many robotic centres of excellence are starting to relegate conventional laparoscopy to the reserves. One main reason is as urologists get better in robotic assisted partial nephrectomies for increasing complex tumours, radical nephrectomies are now reserved for the most complex and largest of renal tumours and robot assistance in such cases are increasingly preferred. Adrenalectomy appears to be the final frontier of the robot's foray into urological surgeries. But is it ready for prime time yet?
This review aims to study the available evidence comparing the techniques and surgical outcomes of robotic assisted adrenalectomy and laparoscopic adrenalectomy.
METHODS
A literature review was performed using PubMed to identify relevant studies. Searches were performed with the following keywords: laparoscopic adrenalectomy and/or robotic and searches were restricted to publications in English. There were a total of 26 studies identified, reporting the techniques and perioperative outcomes of robotic assisted adrenalectomy, robotic assisted partial adrenalectomy or single port robotic assisted adrenalectomy (SPRA). The principles of the Helsinki declaration were followed in this review.
SURGICAL TECHNIQUES
Surgical management of adrenal disorders has seen a paradigm change in its approach. Many centres have performed robotic assisted adrenalectomy successfully, establishing it as a safe, feasible and effective approach. With the use of the da Vinci robotic system, challenges and limitations associated with pure laparoscopic surgery are alleviated while preserving the benefits of minimally invasive surgery. The superior ergonomics, 3-dimensional magnification of the operative field, tremor filtration and the Endowrist technology of robotic instruments providing a greater range of motion as compared to the human hand has allowed for easier handling of the fragile adrenal gland surrounded by major vessels and viscera in a confined space.
The lateral transperitoneal and the posterior retroperitoneal approaches are the commonest approaches adopted by most centers during robotic assisted adrenalectomies.
The operative details of studies reporting their techniques on robotic assisted adrenalectomy are detailed in Table 1 [8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33].
Table 1
Operative details of studies reporting their robotic assisted adrenalectomy techniques
Patient positioning
Robotic assisted or conventional laparoscopic adrenalectomy can be performed via a transperitoneal or retroperitoneal approach. The transperitoneal approach provides greater working space, facilitates orientation by providing readily identifiable anatomical landmarks and better visualisation of surrounding anatomical structures. It also provides greater versatility in the angles of approach of laparoscopic trocars and instruments. In the lateral approach, peritoneal contents fall medially to give greater surgical exposure. In the supine position, both adrenal glands can be accessed without the need for intraoperative repositioning.
For robotic assisted transperitoneal adrenalectomy, most centres describe a lateral transperitoneal technique where patients are usually positioned in the lateral decubitus or modified lateral position with varying degrees of tilt of between 30 to 60 degrees.
Adrenalectomy can also be performed via the retroperitoneal approach. This approach mimics open surgery with its avoidance of the peritoneal cavity. This becomes the main advantage of this approach, as the adrenal gland is right against the thoracic cage when accessed from the back. There is also no entry into the peritoneal cavity and complications associated with intraperitoneal access such as intraperitoneal visceral injury, problems associated with pneumoperitoneum and adhesion formation are reduced. As such, it may be the preferred approach in patients requiring access to bilateral adrenal glands and in patients with multiple previous abdominal surgeries where intraperitoneal surgery may be more challenging due to previous adhesion formation. The greatest limitation with retroperitoneal adrenalectomy, however, is the limitation in working space which increases the technical difficulties of the operation.
Eight centres have described their techniques for robotic assisted posterior retroperitoneal adrenalectomy [8, 15, 17, 19, 20, 22, 25, 28, 29]. In these centres, the patients are positioned in a prone position with the table flexed into a jack knife position.
Port placement
Port placement and the choice of port size is surgeon dependent. Most techniques describe a port placement conf iguration of between 3–5 ports f or lef t sided adrenalectomy with one additional port required for right sided adrenalectomy to aid in liver retraction. More details regarding port placement are shown in Table 1. In comparison to laparoscopic surgery, 4 ports are typically used in the transperitoneal approach with an option for an additional port inserted to aid in difficult dissection. Three ports are usually utilized in adrenalectomy performed using the retroperitoneal approach.
In recent years, laparoendoscopic single site (LESS) adrenalectomy has been described based on the principle that with a smaller number of incisions and ports, enhancement of cosmesis and reduction of associated port site complications can be attained. Both the retroperitoneal and transperitoneal approaches have been described for LESS adrenalectomy with variable strategies in terms of patient positioning, incision sites and ports placement. Usually a 2- to 3-cm incision is required for the insertion of a multiport device, typically described to be placed at the umbilicus for cosmetic benefits. Careful preoperative assessment and patient selection are imperative in minimizing challenges during surgery, reducing complications and ensuring quality outcome.
The disadvantages of LESS adrenalectomy include that of reduced distance between ports and loss of instrument triangulation resulting in cross over and paradoxical movement of instruments, as well as suboptimal approach to the adrenal gland and inadequate counter-traction. Nozaki et al. [34] described their technique of intraumbilical access to solve the problem associated with crossover instrumentation during LESS adrenalectomy. This involves a longitudinal incision of the umbilicus and a wider area of subcutaneous tissue dissection to accommodate multiple ports. The incision length remains within the depression of the umbilicus therefore preserving normal umbilical appearance.
Few centres have reported their experience with robotic assisted single port adrenalectomy [26, 27, 28, 29] performed via both the transperitoneal and the retroperitoneal approaches. Park et al. [28] reported their initial experience with robotic single site posterior retroperitoneal approach, demonstrating its safety and feasibility. In their described technique, the operation is performed in the prone jack knife position, with a 3-cm transverse skin incision made just below the lowest tip of the 12th rib. For the transperitoneal approach, the patient is placed in a flexed lateral decubitus position, with a ipsilateral middle quadrant incision made for the single site port.
TRANSPERITONEAL VERSUS RETROPERITONEAL ADRENALECTOMY
Some retrospective comparisons of laparoscopic retroperitoneal and transperitoneal approaches tend to favour the retroperitoneal approach. Several operative parameters have been found to favour adrenalectomy performed via the retroperitoneal approach. These include shorter hospital stay [35, 36, 37, 38], faster resumption of oral intake [35, 38], decreased analgesic requirement and postoperative pain which in turn leads to earlier ambulation [37, 39], shorter operative time [37, 39], blood loss [38, 39], and morbidity [40] associated with the procedure. The major benefit of the retroperitoneal approach is that with the adrenal against the ribcage at the back, there was no need to move any other organs out of the way. By mimicking open surgery, the peritoneal cavity is avoided, eliminating bowel handling and potential for injury to the intra-abdominal viscera. Walz et al. [41] reported that out of 142 patients who had posterior retroperitoneal adrenalectomy, half the patients did not require any postoperative analgesia and only five required pain medication for more than 24 hours postoperatively. Faster resumption of oral intake, together with decreased analgesia requirement and postoperative pain, may all contribute towards a shorter convalescence and hospital stay. While patients with smaller tumours, lower body mass index and bilateral adrenal pathologies and having significant prior abdominal surgery tend to benefit from retroperitoneal approach, patients with a higher body mass index with larger tumours and no prior abdominal surgeries tend to benefit more from the lateral transperitoneal approach [42]. These 2 approaches were found to be complementing and not competitive to each other when certain patient selection criteria are followed.
There have been descriptions of robotic assisted posterior retroperitoneal adrenalectomy [17, 19, 20, 22] including descriptions of robotic assisted single port retroperitoneal adrenalectomy [28, 29]. In a comparison between robotic assisted posterior retroperitoneal adrenalectomy and laparoscopic posterior retroperitoneal adrenalectomy, it was found that beyond the initial learning curve, robotic assisted posterior retroperitoneal adrenalectomy shortens the skin to skin operative time by 28 minutes when compared with the laparoscopic approach. However, this may be nullified should there be additional intraoperative time used for transportation of the robotic unit to the operating room, starting up of the system, calibration of the robotic cameras and draping of the robotic arms. There was also lower immediate postoperative pain level for patients who underwent robotic assisted posterior retroperitoneal adrenalectomy [22]. Nevertheless, more randomised controlled trials need to be performed to study more meaningful outcomes and measures before this procedure can be justified.
ROBOTIC ASSISTED PARTIAL ADRENALECTOMY
Robotic assisted laparoscopic partial adrenalectomy has been described in various studies [30, 31, 32, 33] to be safe and technically feasible with excellent short term functional and oncologic outcomes. Current indications for partial adrenalectomy include bilateral benign adrenal lesions, a solitary adrenal gland or unilateral tumours in patients with hereditary syndromes. Partial adrenalectomy has also been shown to be feasible in excision of adrenal metastasis in patients with a solitary adrenal gland. While adrenal sparing surgery offers selected patients a substantially better quality of life without the need for lifelong hormonal supplementation, the use of minimally invasive procedures in the treatment of malignant adrenal lesions have always been controversial in view of the potential problems of incomplete resection and risk of recurrence.
Certain technical modifications have been described by Asher et al. [31] to facilitate successful completion of partial adrenalectomy. Extreme flank positioning with axis of robotic ports directed at ipsilateral clavicle allows for easier access to the adrenal gland and for better visualisation of the upper retroperitoneum. The liver must also be well mobilised to allow access to the supra-adrenal vena cava on the right side so that short hepatic veins can be appreciated. Dissection should also be carried out between the pseudocapsule of the lesion and normal adrenal gland to minimise bleeding. The advantage of the robotic platform over traditional laparoscopy may best be appreciated during tumour resection whereby the articulation of the robotic instruments allows easier dissection around the tumour deep within the adrenal gland, taking care to minimize handling of normal adrenal tissue and to reduce the use of cautery to preserve adrenal blood supply.
LAPAROSCOPIC AND ROBOTIC SURGERY FOR LARGE ADRENAL TUMOURS
Minimally invasive resection of large adrenal tumours can be challenging due to a higher risk of complications and greater concerns of malignancy. The transperitoneal approach has been shown to provide greater exposure for resection of larger tumours, with studies showing preference for this approach when tumours are larger than 5 cm [43]. Resection of adrenal masses larger than 6 cm can be challenging when performed via a restricted retroperitoneal space [44]. Comparing to laparoscopic adrenalectomies for large adrenal tumour, the use of robotic assistance has been shown to shorten operative time and decreased the rate of open conversion when compared to laparoscopic adrenalectomy for tumours larger than 5 cm [8]. This can be due to the fact that the robotic instruments are wristed whereas laparoscopic instruments are rigid as well as a three dimensional view which made dissection faster and more accurate in robotic assisted adrenalectomy.
LESS ADRENALECTOMY
Meta-analysis comparing LESS adrenalectomy versus conventional laparoscopic surgery showed no significant difference in estimated blood loss, time to oral intake resumption, complications, conversion and transfusion rates between the 2 groups [45, 46, 47, 48]. However, patients who have undergone LESS adrenalectomy have a significantly lower postoperative visual analog pain score [46] or had less analgesia demand [47]. Hospital stay was also found to be similar [46] or shorter [45, 47, 48] when LESS adrenalectomy was performed. Operative time was however, found to be longer, though Ishida et al. [48] noted that when LESS adrenalectomy was performed, adjustment of the roticulator took an addition of 14.5±8.1 minutes, and in their retrospective case control study, when this time was taken off operative time for LESS adrenalectomy, the operative time was more comparable when compared to conventional adrenalectomy (76.7 minutes vs. 74.3 minutes, p=0.880). LESS adrenalectomy has been proven to be a safe and feasible alternative. Apart from superior cosmesis, current evidence appears to also offer an advantage of shorter convalescence and decreased postoperative pain when compared to conventional laparoscopic adrenalectomy.
SPRA has also been described using both the transperitoneal and retroperitoneal approach [26, 27, 28, 29]. While most perioperative outcomes of SPRA were comparable to laparoscopic adrenalectomy, it was found that operative times were shorter for unilateral adrenalectomy (130±8 minutes for SPRA and 188±12 minutes for laparoscopic adrenalectomy) and there was also statistically significant lower narcotic use in the first 24 hours after surgery. While length of hospital stay as well as cost trended to be lower for robotic single port adrenalectomy, these results were not found to be statistically significant [27].
SURGICAL OUTCOMES
Systematic reviews and meta-analyses of current evidence available have demonstrated the safety and efficacy of robotic assisted adrenalectomy when compared to laparoscopic adrenalectomy.
COMPARING ROBOTIC AND LAPAROSCOPIC ADRENALECTOMY
In 2004, Morino et al. [13] in a prospective randomized controlled study comparing robotic and laparoscopic adrenalectomy concluded that laparoscopic adrenalectomy was superior to robotic assisted adrenalectomy in terms of feasibility, morbidity and cost in view of longer operative time, higher 30-day complication rate and a similar length of hospital stay. However, since then, many subsequent retrospective studies and meta-analyses have been performed comparing the outcomes of robotic versus laparoscopic adrenalectomy which demonstrates equivalence if not superior outcomes for robotic assisted adrenalectomy.
Perioperative outcomes of the robotic assisted adrenalectomy studies are presented in Table 2 [8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33]. Perioperative outcomes for laparoscopic adrenalectomy within the same study were also included.
Table 2
Reported perioperative outcomes of robotic assisted adrenalectomy studies, including studies which provided a comparison to perioperative outcomes after laparoscopic adrenalectomy within the same study
Operative times
There is a wide range of operative times reported by different centres with a mean reported time of between 98 to 234.4 minutes. Brunaud et al. [12] identified several criteria that had an impact on operative time such as surgeon experience, first assistant training level as well as tumour size, with tumours less than 4.5 cm having a shorter operative time. Longer operative times were typically demonstrated in the initial part of the learning curve. This can be partly attributed to time spent docking the robot. Once the ports are placed in traditional laparoscopic surgery, the operation commences. However, in robotic surgery, after the ports are placed, the robot tower must then be docked with instruments inserted, and this has been found to increase operative time by between 15–40 minutes [24] with initial docking time to be reported to be as long as 1 hour [12]. While these can be streamlined with increasing experience, this is still an extra step when compared to laparoscopic surgery. However, beyond the initial learning curve, Agcaoglu et al. [22] reported a significant improvement in operative time after the 10th procedure, and the difference in operative time can be eliminated from as early as the 20th operative case [12]. They reported that the mean operative time decreased 134 minutes in the last 45 cases compared with first 50 cases and by multiple regression analysis, surgeons experience, first assistant level and tumour size were independent predictors of operative time. Brandao et al. [49] in a meta-analysis comparing robotic and laparoscopic adrenalectomy found no statistical difference between the operative times between the 2 procedures. Karabulut et al. [19] also found that the time spent for individual steps of procedure was similar between the laparoscopic and the robotic group and even though the tumour size was larger in the robotic groups.
Duration of hospital stay
The duration of hospital stay in the robotic assisted studies reported a mean range of 1.1 to 6.4 days. Perioperative outcome studies have reported a shorter hospital stay when robotic assisted adrenalectomy is performed when compared to laparoscopic adrenalectomy [15, 19, 49]. Karabulut et al. [19] found that in their cohort of patients, the main reasons for hospital stay in the robotic group was for nausea, atelectasis and the need for pain control, and all patients were discharged within 2 days. This is in comparison to their patients who underwent laparoscopic adrenalectomy who stayed between 1–4 days. This shorter hospital stay is possibly the result of a combination of various improved outcomes such as a shorter operative time and lesser blood loss, though hospital stay can be an unreliable outcome parameter for comparison as it can be confounded by many factors.
Blood loss
One other significant outcome in favour of robotic surgery was the lower estimated blood loss. Reported mean blood loss ranged from less than 50 mL to 576 mL, with most centres reporting mean blood loss of less than 100 mL. Bilateral adrenalectomies tend to result in greater blood losses. Lee et al. [26] reported a mean of 1,698 mL (150–6,140 mL) in their 5 cases of bilateral robotic assisted single site adrenalectomy that were performed. Pineda-Solís et al. [50] in their retrospective study found that the blood loss tended to be lower in the robotic group versus the laparoscopic group (30±5 mL vs. 55±74 mL, p=0.07) though this was not statistically significant. Other studies also reported equivalence in terms of intraoperative blood loss [14, 21]. Brandao et al. [49] in their meta-analysis comparing outcomes between robotic assisted adrenalectomy and laparoscopic adrenalectomy, found that 7 out of 9 studies reported less bleeding for the robotic group with a statistically significant difference between the 2 groups. However, this difference may not be clinically significant and that both techniques can be performed with minimal associated blood loss.
Conversion rates
In current literature, low conversion rates have been reported for both robotic and laparoscopic adrenalectomy [49]. Conversion rate for robotic assisted adrenalectomy were reported to range between 0% to 40% for laparoscopic conversion and 0% to 10% for open conversion while open conversion rates in the laparoscopic studies ranged between 0% to 10.5%. Of note, in both groups, there were many studies which reported a 0% conversion rate. Common reasons for conversion in robotic cases cited included adherence of the tumour to surrounding structures or adhesions (5 cases) or bleeding (4 cases). Other reasons included poor visualisation of structures (2 cases), technical difficulties resulting in incomplete isolation, camera malfunction and failure to progress (1 case each). Conversion rate for robotic cases was found to decrease with increasing surgical experience [13].
Complication rates
Studies comparing robotic and laparoscopic adrenalectomy reported same or superior results for the robotic group in postoperative complications rate (7% vs. 11%) [11]. Meta-analysis [49] performed comparing these outcomes also showed a nonstatistically significant difference in a higher complication rate in the laparoscopic group (6.8% vs. 3.6%, p=0.05) There were more reported severe complications in the laparoscopic groups including grade 4 and 5 complications according to the Clavien-Dindo classification system grading system. Reported complications in the robotic group were generally of a lesser degree of severity [49]. Postoperative morbidity and mortality have been demonstrated to be comparable to conventional laparoscopy [13].
LEARNING CURVE
It is well known that being early in a surgeon's learning curve is associated with worse perioperative outcomes and increased complications. It has been estimated that the learning curve of laparoscopic adrenalectomy is between 20–40 cases [51, 52] while that of robot-assisted transperitoneal adrenalectomy is only about half, ranging between 10–20 cases [12, 22]. This is especially important for lower volume surgeons as the inherent advantages of the robotic platform may help surmount the initial learning curve faster, leading to better perioperative outcomes and reduced complications.
COST AND QUALITY OF LIFE ASSESSMENTS
One of the major points of criticism with robotic surgery has always been the higher cost factor. Brunaud et al. [53] found that when cost evaluation was performed using baseline cost in their hospital, robotic adrenalectomy was 2.3 times more costly than laparoscopic adrenalectomy. (4,102 euro vs. 1,799 euro). Total cost was found to be most affected by the total number of robotic cases per year and depreciation of the robotic system. Operative time, in contrast, was found to only play a minor role in the overall cost. This finding was also echoed by Morino et al. [13] who found a difference of $729 excluding the capital investment of the da Vinci robotic system. This increased expense was mainly due to the use of semidisposable robotic instruments and longer operative time. However, it is to be noted that these studies were performed in the earlier era of robotic assisted adrenalectomy. With increasing volumes and improved outcomes associated with robotic assisted adrenalectomy, more up to date cost analysis studies should be performed to evaluate this parameter. Arghami et al. [27] analysed the cost associated with single-port robotic adrenalectomy and found that in their health system, as there are no specific billing codes for robotic assisted adrenalectomy with similar reimbursement compared to the laparoscopic technique, a robotic procedure adds about $950 to the cost compared to laparoscopic adrenalectomy. However, they found that the total bill cost for single port robotic adrenalectomy was 16% lesser than laparoscopic adrenalectomy, which may be related to shorter hospital stay and an approximately 50% reduction in narcotic use. Probst et al. [54], in a recent paper comparing costs of robotic adrenalectomy and open adrenalectomy demonstrated that the additional costs of robotic surgery were equalized if at least 150 cases of robotic procedures were performed per year based on certain healthcare cost assumptions within the healthcare system.
In terms of quality of life assessment, no significant difference was observed for all Short Form 36 health survey scores between patients after laparoscopic or robotic adrenalectomy except for role limitations due to emotional problems. These were increased after 6 weeks in patients who underwent robotic adrenalectomy. There was also no significant difference regarding state and trait anxiety, postoperative pain, quality of sleep and sleep duration [53].
CONCLUSIONS
Current evidence has shown that robot assisted adrenalectomy can be performed safely and effectively with equivalent or even superior outcomes compared to laparoscopic adrenalectomy with potential advantages of shorter operative times in high volume centres, reduced blood losses, shorter hospital stay and decreased intraoperative blood loss.
However, there is still a paucity of reports on perioperative and long term outcomes these needs to be evaluated in well-designed prospective randomized controlled trials with adequate power and follow-up. Further more detailed cost analysis are also required to justify the higher costs associated with robotic assisted adrenalectomy.
And so it seemed that it is a stalemate in the war between robot and man along the frontlines of adrenalectomy at this point in time. As to who will ultimately emerge victor, only time will tell.
CONFLICTS OF INTEREST:The authors have nothing to disclose.
References
-
Piazza L, Caragliano P, Scardilli M, Sgroi AV, Marino G, Giannone G. Laparoscopic robot-assisted right adrenalectomy and left ovariectomy (case reports). Chir Ital 1999;51:465–466.
-
-
Hubens G, Ysebaert D, Vaneerdeweg W, Chapelle T, Eyskens E. Laparoscopic adrenalectomy with the aid of the AESOP 2000 robot. Acta Chir Belg 1999;99:125–127.
-
-
D'Annibale A, Lucandri G, Monsellato I, De Angelis M, Pernazza G, Alfano G, et al. Robotic adrenalectomy: technical aspects, early results and learning curve. Int J Med Robot 2012;8:483–490.
-
-
Akarsu C, Dural AC, Kankaya B, Çelik MF, Köneş O, Mert M, et al. The early results of our initial experience with robotic adrenalectomy. Ulus Cerrahi Derg 2014;30:28–33.
-
-
Okoh AK, Berber E. Laparoscopic and robotic adrenal surgery: transperitoneal approach. Gland Surg 2015;4:435–441.
-
-
Park JH, Walz MK, Kang SW, Jeong JJ, Nam KH, Chang HS, et al. Robot-assisted posterior retroperitoneoscopic adrenalectomy: single port access. J Korean Surg Soc 2011;81 Suppl 1:S21–S24.
-
-
Terachi T, Yoshida O, Matsuda T, Orikasa S, Chiba Y, Takahashi K, et al. Complications of laparoscopic and retroperitoneoscopic adrenalectomies in 370 cases in Japan: a multi-institutional study. Biomed Pharmacother 2000;54 Suppl 1:211s–214s.
-
-
Wu S, Lai H, Zhao J, Chen J, Mo X, Zuo H, et al. Laparoendoscopic single-site adrenalectomy versus conventional laparoscopic adrenalectomy: an updated meta analysis. Urol J 2016;13:2590–2598.
-
-
Pineda-Solís K, Medina-Franco H, Heslin MJ. Robotic versus laparoscopic adrenalectomy: a comparative study in a high-volume center. Surg Endosc 2013;27:599–602.
-
-
Probst KA, Ohlmann CH, Saar M, Siemer S, Stoeckle M, Janssen M. Robot-assisted vs. open adrenalectomy: evaluation of cost effectiveness and perioperative outcome. BJU Int. 2016 May 12; [doi: 10.1111/bju.13529][Epub].
-
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