Comparison of Transperitoneal Versus Retroperitoneal Laparoscopic Adrenalectomy in a Prospective Randomized Study

Introduction

With the rising costs of health care, the main concern is to reduce the patient's hospital stay and improve recovery. As a result, minimal invasive surgery has played a greater role in the treatment of various diseases.^1,2 There is no question that laparoscopy has become the surgical technique of choice for adrenalectomy in the last two decades after the introduction of this procedure by Gagner et al. ¹ Laparoscopic adrenalectomy can be performed transperitoneally or retroperitoneally. The transperitoneal approach has the benefit of a wider working space and identifiable anatomical landmarks. The retroperitoneal approach has been thought to be associated with earlier recovery of bowel functions, possibly leading to a shorter hospital stay and early recovery.^3–5 Most studies that compared the two approaches for laparoscopic adrenalectomy have been retrospective.^6–9 To date, only a few prospective, randomized comparisons of transperitoneal laparoscopic adrenalectomy (TLA) versus retroperitoneal laparoscopic adrenalectomy (RLA) have been published.^9,10

We report here our prospective, randomized comparisons of TLA versus RLA in 24 patients with medium-term follow-up.

Subjects and Methods

Between September 2008 and November 2011, 24 patients with surgical adrenal diseases were prospectively randomized to undergo TLA (Group 1, 11 patients) or RLA (Group 2, 13 patients). All patients were referred by an endocrinologist. They underwent a complete endocrinological work-up prior to surgery. The indications for laparoscopy were as follows: 7 Cushing's adenomas, 3 aldosterone-producing adenomas, 10 nonfunctional adenoma,s and 4 pheochromocytomas. Study exclusion criteria were patients with morbid obesity (body mass index >40 kg/m²), prior major abdominal surgery, clinical suspicion of malignancy, tumor size >6 cm, and bilateral adrenalectomy. Patients were prospectively randomized by a computer-generated program. All patients provided consent for either approach. The study was approved by the institutional review board of our institution (Urology, Nephrology & Kidney Transplant Research Center) and the regional ethical committee. All the surgeries were done by a single surgeon in the lateral flank position.

In the transperitoneal approach, after insufflation of the abdomen, four trocars were placed along the costal margin. The line of Toldt was incised, the left or right colon was medially mobilized, and on the right side the duodenum was dissected away by the Kocher maneuver. The adrenal vein was dissected out, ligated, and divided using surgical clips. The adrenal arterial supply was divided as the adrenal was dissected free. The remaining attachments to the kidney were divided bluntly. The specimen was placed in an endoscopic sac and extracted. The operative field was examined for bleeding with the insufflation pressure turned down to 5 mm Hg.

In the retroperitoneal approach, a 15-mm incision was made under the tip of the 12th rib. The underlying muscle and fasciae were divided with cautery, and the surgeon's index finger was inserted through the incision and used to develop a plane between the posterior Gerota's fascia and the psoas fascia and to put the trocar in position. Blunt dissection was performed under direct vision using a laparoscope. After insufflation of the retroperitoneum, a 5-mm trocar was placed at the angle of the paraspinal muscle and the origin of the 12th rib, and a 10-mm trocar was placed about two fingerwidths above the iliac crest near the anterior superior iliac spine. The rest of the procedure was the same as the transperitoneal approach.

The primary surgeon (M.R.M.-F.) was informed about the preselected laparoscopic approach for each individual patient in the operating suite just before the surgery. Intraoperative data were documented by the surgeon in the operating room immediately at the end of the procedure using a previously designed data sheet. Information that was analyzed included patient demographics, preoperative adrenal characteristics, intraoperative and postoperative outcomes, and pathological adrenal features. Tramadol (50 mg) infusion was used as the analgesia at the recovery room and every 4 hours in the early postoperative period, with a maximum dose of 400 mg/day. The primary outcome was the convalescence period, defined as the period needed for complete recovery from the physical aftereffects of surgery and return to normal personal jobs. Current follow-up was obtained by serial visits of each patient during the follow-up time.

Statistics were performed with SPSS version 16 software (SPSS Inc., Chicago, IL) using the Wilcoxon rank sum test for continuous variables and the chi-squared or Fisher's exact test for categorical variables, with P<.05 considered statistically significant.

Results

Baseline demographics were comparable in Groups 1 and 2 (Table 1) with respect to patient age (42.90 versus 42.23 years; P=.80), sex (45.5% male and 54.5% female in Group 1 versus 38.5% male and 61.5 % female in Group 2; P=.72), body mass index (26.72 versus 27.46 kg/m²; P=.62), and laterality (54.5% right and 45.5% left versus 61.5% right and 38.5% left; P=.72). Median adrenal mass size was 2.92 cm (range, 2–5 cm) in the transperitoneal group and 2.63 cm (range, 2–5 cm) in the retroperitoneal group (P=.55).

The two approaches were similar in operative times (129 versus 128 minutes; P=.22), estimated blood loss (66.36 versus 65.83 mL; P=.83), time to ambulation (1.7 versus 1.4 days; P=.21), hospital stay (3.63 versus 3.08 days; P=0.25), analgesic (tramadol 50 mg) requirements (2.8-mg versus 2.4-mg doses; P=.4), and postoperative pain graded on a visual analog scale index (5.54 vs. 4.75; P=.4).

However, the time to oral intake resumption (20 versus 8.25 hours; P=.001) and convalescence (4.45 versus 2.25 weeks; P=.002) were significantly shorter in the retroperitoneal group (Table 2). Laparoscopic adrenalectomy was successfully performed in 24 patients, with one open conversion in Group 2 because of the failure to progress. The open conversion in Group 2 was in a patient with a 5-cm right pheochromocytoma with dense inferior vena cava adhesion. Pathological data on the intact extracted specimens were similar in the two groups (81.8% adrenal adenoma and 18.2% pheochromocytoma versus 84.6% adrenal adenoma and 15.4% pheochromocytoma; P=.90) (Table 3). Postoperative complications (low-grade fever) occurred in 1 patient from each group (8.3%). Need for blood transfusion, hematuria, and urinary retention did not occur in any group. So, all of the complications were limited to Grade I of the modified Clavien system. The mean follow-up was 9 months in both the retroperitoneal and transperitoneal groups. During this time, there were no late complications such as portal-site hernia, and no patient died.

Discussion

Minimally invasive techniques have profoundly changed the surgical approach to the adrenal gland. The clear discrepancy between the relative small size of the target organ and the extent of the incision necessary to provide adequate exposure is not be found in any other urologic ablative procedure compared with adrenal surgery. Because of the establishment of the laparoscopic approach that circumvents this drawback (while incorporating all advantages of the open approach), it has become the general accepted standard of care for surgical management for the vast majority of cases in little over a decade. ³

Surgery of the adrenal gland consists of operative procedures to correct endocrine abnormalities or to treat malignant diseases. Various adrenal disorders can be identified and treated medically. When medical therapy is ineffective or does not exist for a particular adrenal disease, surgery becomes necessary.

There are four laparoscopic approaches to the adrenal gland: the transperitoneal approach, the retroperitoneal approach, hand-assisted surgery, and the robotic adrenalectomy technique. In all laparoscopic adrenalectomy approaches, the anterior side of the adrenal gland is accessed, and the early identification and ligation of adrenal vascular supply are facilitated. ¹¹

In the case of laparoscopic adrenalectomy, both the transperitoneal and retroperitoneal approaches have proven to be feasible and safe. ¹² TLA can be performed either through an anterior supine approach or a lateral approach, whereas retroperitoneal access could be achieved by either the posterior or lateral approach. ⁹

The transperitoneal approach provides the largest working space, facilitates orientation by providing readily identifiable anatomic landmarks, and affords greater versatility in angles under the direction of laparoscopic trocars and instruments, resulting in the smallest size and number of ports. The equipment is mature, and techniques are well defined, but like any other approach, it requires significant expertise in instrument manipulation and suturing. The major benefit of the retroperitoneal approach is that the surgeon does not need to move any other organs out of the way (i.e., spleen, liver, pancreas, colon, etc.) because the adrenal gland lies right against the ribcage in the back. This technique means that it may be performed faster than the traditional transabdominal approach. In addition, this may be a better technique for patients having both adrenal glands removed (because the patient does not need to be “flipped over” in order to get to the other side) and for those with extensive scar tissue in their abdomen from previous surgery. In addition, some surgeons believe that patients have less postoperative pain. The retroperitoneal approach mimics open surgery because the peritoneal cavity is avoided. This creates a potential space to visualize the surgical field and avoids bowel handling and the potential for injury to the intra-abdominal viscera. It may be preferred for selected cases of laparoscopic patients who have undergone multiple prior abdominal surgeries.^3,11

In the realm of urology, it is safe to state that today's adrenal surgery is the success story of laparoscopy. This prospective randomized study was designed to objectively assess whether the transperitoneal versus the retroperitoneal approach for laparoscopic adrenalectomy translated into any practical clinical differences in patient outcomes. To this end, specific factors that were known to increase the difficulty of either approach, such as morbid obesity and prior surgery in the area of interest, were excluded from the study. All the surgeries were done by a single surgeon (M.R.M.-F.) in the lateral flank position. Patient demographics and baseline characteristics were comparable and showed no significant differences. Our study found no significant differences in operative time, estimated blood loss, or complication rates between the two groups. These data confirmed that, with the constraints of a limited working space not withstanding, the retroperitoneal approach is technically more efficient because it takes advantage of naturally existing anatomical planes.

Certain technical aspects of the retroperitoneal approach require emphasis. In this approach with the patient in the full lateral position, with hips flexed and the kidney rest elevated, a 15-mm incision was made on the 2-cm point below the tip of the 12th rib, between the rib and the anterior superior iliac spine. The index finger was inserted through the incision and used for blunt dissection to create a hole from the skin through the muscle into the retroperitoneal space to put the trocar in position. After initial dissection of the retroperitoneum (without using balloon dilation, due to anatomical landmarks such as the psoas muscle posterior, Gerota's fascia anterior, and the diaphragm superior), all operations were performed in the retroperitoneum. The retroperitoneal approach can be applied with equivalent efficacy to the right or left adrenal gland. We believe that in the obese patients, especially on the right side, retroperitoneal adrenalectomy may be somewhat technically simpler than the transperitoneal approach. This is due to the fact that in the case of some morbidly obese patients, the abdominal pannus fat tends to fall away from the operative site when the patient is in the full 90° flank position, making the transperitoneal approach complicated, especially when there is a big fatty liver.

In 2000 Terachi et al. ¹³ published a retrospective multi-institutional study, comparing the results of 370 patients who underwent RLA and TLA. They believed that the procedure in the RLA group had a lower morbidity rate than in the TLA group. They also commented that more skill is required to overcome the drawback of the narrower working space and fewer anatomical landmarks in the RLA procedure.

Some retrospective comparisons of retroperitoneal with transperitoneal laparoscopy tended to favor the retroperitoneal approach. Bonjer et al. ¹⁴ showed an advantage in operative time (75 minutes versus 150 minutes; P=.005), blood loss (20 mL versus 150 mL; P=.01), postoperative analgesia (6 mg versus 20 mg of morphine sulfate; P=.003), and hospital stay (4 versus 6 days; P=.027) for the retroperitoneal over the transperitoneal approach. Suzuki ¹⁵ also found less blood loss, shorter convalescence, and faster resumption of oral intake with retroperitoneal surgery than with anterior and lateral transperitoneal procedures.

In 2005 Rubinstein et al. ⁹ published an exclusive prospective article with long-term follow-up of TLA versus RLA comparisons. In their study, all operative parameters, baseline demographics, and preoperative and postoperative data (including the time to oral intake) were similar in the transperitoneal and retroperitoneal approaches, although they noted convalescence was significantly more rapid in the retroperitoneal group. They revealed that in most benign adrenal lesions that required surgery, laparoscopic adrenalectomy can be performed safely and effectively by the transperitoneal or the retroperitoneal approach.

Berber et al. ¹⁶ published a retrospective research in 2009 that compared patients with an adrenal mass who underwent laparoscopic adrenalectomy between 1994 and 2008, using the posterior retroperitoneal and lateral transperitoneal approaches. With that experience, they showed that the lateral transperitoneal and posterior retroperitoneal techniques have a similar postoperative outcome when patients were selected based on certain criteria. They claimed that patients with small tumors, lower body mass index, and bilateral adrenal pathologies and having significant prior abdominal surgeries will benefit from the retroperitoneal approach. On the other hand, the transperitoneal approach was beneficial to patients with higher body mass index and carrying larger tumors who had had no prior abdominal surgeries. In their study, the estimated blood loss and duration of hospital stay were shorter in the retroperitoneal group. At the end, they concluded that the lateral transperitoneal and posterior retroperitoneal approaches were complementing and not competitive to each other when certain patient selection criteria are followed. ¹⁶

We started our study in September 2008. Up until November 2011, we gathered data on 24 patients. Our results showed no significant differences in baseline demographics and preoperative and postoperative data between the two groups. All operative parameters were similar in the two groups except the convalescence and time to oral intake resumption, which were significantly shorter in the retroperitoneal group. Our study showed different results in comparison with the study of Rubinstein et al. ⁹ in terms of time to oral intake resumption, which was significantly shorter in our retroperitoneal group. The criteria to permit oral intake resumption were based on patients passing gas and serial bowel sound examination.

The analgesic requirements, postoperative pain according to a visual analog scale index, and time to ambulation after surgery showed better results in the retroperitoneal group in our study, although the differences were not significant.

It seems that RLA for benign adrenal masses with small sizes (less than 6 cm) correlates with better results in terms of time to oral intake resumption and convalescence. But, to improve this theory, more cases have to be studied. In this study, it must be recognized that the retroperitoneal approach was done by an expert surgeon who is extensively experienced and facile with the retroperitoneal approach.

Finally, we know that in our study the number of patients was few, and follow-up time was short, which compromised our results. However, it is important to note that prospective, randomized studies comparing the transperitoneal versus the retroperitoneal approach for laparoscopic adrenalectomy are difficult to perform and therefore are rarely found in the literature. ⁹

We propose that future studies should compare the robotic-assisted versus conventional laparoscopic adrenalectomy procedures in this area.

Conclusions

Laparoscopic adrenalectomy is a viable treatment option to remove benign adrenal lesions that can be performed safely and effectively by the transperitoneal or the retroperitoneal approach. The best laparoscopic approach to the adrenals is still a controversial issue because both transperitoneal adrenalectomy and retroperitoneal adrenalectomy have specific advantages and disadvantages. An appropriate selection of patients and adequate access secure successful treatment outcomes. In conclusion, the decision on which approach to use would depend on personal preferences and the skills of the surgeon.