Laparoscopic Adrenalectomy
ARVIN K. GEORGE
LOUIS R. KAVOUSSI
Since Gagner et al. (1) first described laparoscopic adrenalectomy in 1992, this approach has become the preferred technique in the surgical management of most adrenal lesions. Laparoscopic adrenalectomy demonstrates the classical benefits of minimally invasive surgery, with multiple studies supporting reduction in postoperative pain, analgesia requirements, and postoperative morbidity with equivalent functional outcome when compared with traditional open surgery. Advances in minimally invasive surgical techniques have generated the development of multiple approaches to adrenalectomy, including transperitoneal, retroperitoneal, transthoracic/transdiaphragmatic, and most recently robot-assisted surgery. The benign nature of the majority of adrenal disease, combined with the deep retroperitoneal location of the adrenal gland, has lent itself ideally to a minimally invasive approach.
INDICATIONS
Laparoscopic adrenalectomy is a definitive surgical treatment modality for the broad spectrum of adrenal disease. It has been proven safe and effective in the management of benign functioning and nonfunctioning adrenal conditions as well as the majority of malignant neoplasms (Table 11.1). As surgeon experience has increased, the contraindications to the laparoscopic approach have decreased. In the hands of a proficient and practiced surgeon, contraindications have become relative, and the advantages of minimally invasive techniques have afforded urologists the opportunity of a more aggressive approach in treatment (Table 11.2).
DIAGNOSIS
Evaluation generally begins with serum and urine chemistry to distinguish between functioning and nonfunctioning tumors. More specific investigations, combined with the clinical presentation, assist in isolation of a specific pathology when present (Table 11.3). Imaging with computerized tomography (CT) or magnetic resonance imaging (MRI) is an integral step in preoperative assessment, as it provides detailed characterization of adrenal lesions. The presence of significant retroperitoneal and periadrenal fat allows for ready identification of the gland. CT may help delineate malignant versus benign lesions based on their attenuation characteristics, with accuracy approaching 90% in suspected adrenal disease. CT with assessment of washout is the most useful study in categorizing adrenal incidentalomas with a sensitivity and specificity of 98% and 92%, respectively (2). Attenuation of <10 Hounsfield units on noncontrast imaging is sufficient to identify lipid-rich adenomas <4 cm. Contrast-enhanced imaging at 1 and 15 minutes allows for calculation of absolute percentage washout (APW) and relative percentage washout (RPW) to help characterize lipid-poor adenomas. An APW of >60% and RPW of >40% is typical of benign adenomas (3). Chemical shift MRI with axial in- and out-of-phase images can also be used to differentiate incidental adrenal lesions. MRI has a reported sensitivity and specificity of 89% and 99%, respectively, with adenomas exhibiting a lipid-rich composition in distinction to the lipid-depleted nature of nonadenomatous lesions. Intraoperative ultrasound can elicit detailed information regarding internal acoustic appearance, tumor size, extent of invasion if present, and adjacent anatomy. Its use is a defined element in adrenal-sparing surgery and can assist in cases where it is difficult to distinguish the periadrenal fat from the gland proper. Progress in imaging techniques and their interpretation has increased diagnostic accuracy, and they are an essential adjunct in determining diagnosis, operability, and surgical approach.
TABLE 11.1 INDICATIONS FOR LAPAROSCOPIC ADRENALECTOMY | ||||||||||||||
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TABLE 11.2 CONTRAINDICATIONS TO LAPAROSCOPIC ADRENALECTOMY | ||||||||||||||||||
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ALTERNATIVE THERAPY
Alternative treatment for adrenal lesions include conventional open surgery via a transabdominal or retroperitoneal approach, radiofrequency ablation (RFA), and cryoablation (4). Ablative therapies are currently reserved for those patients who are not surgical candidates or who refuse surgery.
RFA provokes local ion agitation and heat, inducing coagulative tissue necrosis. In one recent study, Mayo-Smith and Dupuy (5) demonstrated the successful treatment of hormonally active tumors and small (5 cm) solitary adrenal metastases/adrenocortical carcinoma. RFA has also shown promise in the management of adrenal metastases and select patients with functional masses. In a study of 23 ablations, technical success and good local control in 81% of patients with short-term follow-up was reported, but eventual disease progression occurred in 16 of 19 patients treated for metastatic disease (6).
Cryoablation relies on the Joule-Thomson effect, or the change in temperature that accompanies expansion of a gas (argon) with resultant cooling and formation of intracellular ice crystals. Munver et al. (7) described the first case of cryoablation as an adrenal-sparing procedure for hyperaldosteronism, with subsequent reduction in the need of antihypertensives postoperatively. A retrospective series of 12 patients undergoing cryoablation for adrenal metastases demonstrated local control in 92% of patients, although 50% experienced
hypertensive crisis highlighting the need for preoperative alpha blockade (8).
hypertensive crisis highlighting the need for preoperative alpha blockade (8).
TABLE 11.3 DIAGNOSIS OF ADRENAL LESIONS | ||||||||
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RFA and adrenal cryoablation show potential as less invasive surgical alternatives for small lesions and adrenalsparing procedures in patients who are not ideal surgical candidates. The current experience as described in the literature is limited and further evaluation of such alternative therapies is needed.
SURGICAL TECHNIQUES
The transperitoneal approach is preferred by most surgeons due to the greater working space and familiarity of anatomic landmarks. Retroperitoneoscopic adrenalectomy is generally considered by the more experienced surgeon but may prove useful in patients with significant prior intra-abdominal surgery and/or morbid obesity. Thoracoscopic adrenalectomy was described by Gill et al. (9) for the treatment of select patients with adrenal pathology and significant abdominal and retroperitoneal scarring from previous surgery through access via the virgin thoracic cavity and transdiaphragmatic approach. In an effort to further minimize operative morbidity and improve cosmesis, the introduction of laparoendoscopic single-site (LESS) adrenalectomy has been evaluated. A systematic review of LESS adrenalectomy versus conventional laparoscopic adrenalectomy revealed equivalent complication, conversion, and transfusion rates despite a longer operative time in those undergoing a single-site procedure, likely related to the early experience of this novel technique (10). Additionally, there were comparable cosmetic satisfaction scores, although LESS adrenalectomy demonstrated lower visual analog pain scores. The introduction of robotic technology in the minimally invasive arena has proven to be a successful alternative to other surgeries with specific benefits. Robotic systems aid in eliminating surgeon fatigue, tremor, and provide a three-dimensional visualization of the operative field. However, they represent a more costly option to the healthcare system and require additional training by the surgeon. A prospective trial of laparoscopic versus robot-assisted adrenalectomies failed to show significant benefit in the latter (11). The study demonstrated that robot-assisted adrenalectomy is a feasible alternative to standard laparoscopic surgery with appropriate robotic experience. Ultimately, the choice of surgical technique is dependent on surgeon experience, the patient’s past surgical history, and preoperative findings.
Preoperative Considerations
Prior to operative intervention, metabolic abnormalities associated with hormonally active tumors must be addressed to optimize the patient for surgery. A multidisciplinary approach integrating the patient’s primary care provider, endocrinologist, and urologist ensures appropriate care in the preoperative setting and maintains follow-up after surgery. Hypertension and hypokalemia seen with aldosteronomas are managed with spironolactone. The patient should be maintained normoglycemic with cortisol-secreting adenomas, and stress-dose steroid administration must occur perioperatively. The preoperative management of pheochromocytomas requires special consideration, as inadequate blockade of circulating catecholamines can trigger hypertensive crises secondary to anesthesia or intraoperative manipulation. Patients should receive 14 days of blockade with phenoxybenzamine hydrochloride titrated to control blood pressure. Additional blockade may be indicated if arrhythmias persist or prior treatment proves insufficient.
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