Minimally invasive adrenalectomy (MIA) has become the favored approach for resection of adrenal tumors that are benign. Some indeterminate adrenal masses can also be resected via minimally invasive approaches as long as the masses can be resected completely without capsular violation. The excellent outcomes of MIA have been demonstrated in the hands of experienced surgeons, with fewer complications and shorter recovery compared to open surgery. Since 1992, when Gagner et al. described the first transabdominal laparoscopic adrenalectomy [1], surgeons have explored a range of minimally invasive approaches for adrenalectomy: accessing the adrenal gland via the abdomen or retroperitoneum, using laparoscopic instruments or robotic systems, and applying hand-assisted or single-incision variations. These different approaches to MIA have advantages and limitations that should be considered when develo** an optimal operative plan. Here, we present our approach based on our extensive experience of adrenalectomy over two decades (Table 1).

Table 1 Tumor- and patient-related factors to consider when determining the optimal approach for adrenalectomy
Full size table

Laparoscopic transabdominal approach

The earliest MIA was the laparoscopic transabdominal approach developed in the early 1990s, which typically employs three or four ports along the right or left subcostal margin to expose and resect the adrenal gland. This approach uses an operating space that is similar to other minimally invasive abdominal surgeries, thereby easing the learning curve. Advantages of the laparoscopic transabdominal approach include a larger operating space, access to adjacent organs, and easy conversion to open surgery if necessary. We prefer this approach for patients who have large adrenal tumors generally > 6-8 cm, very anteriorly located adrenal tumors in relation to the kidney (particularly on the left side), body habitus that would make a posterior approach difficult (such as severe scoliosis), back issues, severe morbid obesity, or scenarios where another concomitant abdominal procedure is indicated. Additional ports can be added for ease of resection, as well as placement of hand-assisted ports as an intermediary step between fully laparoscopic or fully open resection.

Hand-assisted MIA

When resecting larger adrenal tumors laparoscopically, surgeons may opt for a hand-assisted variation in which the surgeon inserts their hand into the insufflated abdomen through a hand port in the medial, subcostal position. Most often, surgeons will start with a purely laparoscopic approach and then convert to a hand-assisted approach intraoperatively to facilitate the procedure.

Hand-assisted laparoscopic adrenalectomy draws on the advantages of both open and laparoscopic surgery. The surgeon can improve their tactile sense, allowing for better manipulation of the tumor while minimizing the risk of tumor spillage. Placing a hand port also can help the surgeon gain exposure in the operative field while avoiding an open incision. We do not recommend morcellating adrenal masses and practice intact, touch-free tumor extraction. If the tumors are > 12 cm and do not suggest local invasion by imaging, we often plan an up-front hand-assisted approach. Since our hand port incision is approximately 5 cm in length, it would facilitate both surgery and specimen extraction through this port. There are limited published data on the hand-assisted laparoscopic adrenalectomy, but in our experience, the postoperative recovery is similar to that of the purely laparoscopic approach.

Posterior retroperitoneoscopic adrenalectomy

In the late 1990s, soon after laparoscopic transabdominal adrenalectomy was introduced, posterior retroperitoneoscopic adrenalectomy (PRA) gained acceptance as another minimally invasive approach. Bonjer et al. first performed PRA in the lateral decubitus position, and Walz et al. then popularized PRA using a prone position [2, 3]. PRA is generally performed by inserting three trocars below the twelfth rib and lateral to the sacrospinal muscles and psoas muscle in order to access the retroperitoneal space and adrenal gland. PRA generally is recommended for patients with adrenal tumors up to 6–8 cm or a history of extensive abdominal surgeries, since intraabdominal adhesions can be avoided with this approach. Bilateral adrenalectomy also is easier via a prone approach, as the patient does not need to be repositioned during the case.

However, the main limitation of PRA is the confined operating space, which deters resection of larger tumors or those that are very friable, such as pheochromocytoma. While operating in a confined space, friable tumors are at greater risk of capsule rupture and tumor implantation. Larger, friable tumors generally would be better served by the anterior approach. The authors also examine the patient’s body habitus, assuring that there is at least a 4 cm distance between the 12th rib and the posterior iliac spine to allow insertion of the trocars. Factors that may deter us from pursuing a posterior approach include a very anteriorly positioned left adrenal mass, severe scoliosis to the side of the tumor, very significant retroperitoneal adipose tissue with a small adrenal mass or thick subcutaneous tissue coupled with limited space below the 12th rib, and the presence of severe restricted lung disease or COPD (due to the potential for hypercarbia and difficulty ventilating). Hand-assisted PRA can also be performed by placing a hand port in the flank/lateral incision area. Conversion to an open procedure is more difficult in the prone position, and open posterior adrenalectomy requires excision of the 12th rib in most cases.

Robotic adrenalectomy

Robotic adrenalectomy was first described in 2001 by Horgan and Vanuvo [4]. Compared to laparoscopic instruments, the robot system has the advantages of a three-dimensional visual field, wrist movements, and an ergonomic console for the surgeon to operate from. Also, the surgeon is also able to control all aspects of the case, including the camera arm, two working arms, and a fourth arm that acts as a retractor. These advantages are countered by the higher cost and longer operating time of robotic adrenalectomy, compared to the laparoscopic approach. Like laparoscopy, robotic adrenalectomy can be performed via the transabdominal and retroperitoneal approaches. Perioperative complications have been shown to be comparable between robotic and laparoscopic procedures. The robotic approach may be especially well suited for cases in which cortical sparing adrenalectomy, in which the magnified, three-dimensional visualization may aid preservation of the adrenal cortex.

Single-incision laparoscopic and robotic adrenalectomies

Single-incision laparoscopic and robotic adrenalectomies have also been described. Single-incision adrenalectomy has been advocated as a means to minimize potential complications related to trocar placement, such as injury to viscera, incisional hernia, and surgical site infection. Studies have shown similar outcomes for MIA using a single incision versus multiple incisions, but these studies are small, retrospective, single-institution studies. In the absence of robust data demonstrating benefit to single-incision surgery, surgeon experience is paramount. Surgeons who perform robotic PRA have recommended selecting patients with lower BMI and smaller tumors for those who are learning single-port robotic PRA.

Whether laparoscopic or robotic, transabdominal or retroperitoneal, multiport or single incision, or hand-assisted, tailoring the optimal approach for MIA means that a surgeon should be familiar with the range of available operative options that are described above. They also should perform a high volume of adrenalectomies as part of their practice, as higher case volume has been associated with lower complication rates [5]. Surgeons should choose their approach for minimally invasive adrenalectomy based on their operative experience, patient anatomy and comorbidities, and, importantly, tumor characteristics, with the goals of providing a surgery that is safe, complete, and expeditious.