Endoscopic Approaches to Adrenal Surgery

Abstract

Endoscopic adrenal surgery has revolutionized the management of adrenal disorders by offering minimally invasive alternatives to open adrenalectomy. This review critically appraises the current evidence on endoscopic approaches, including laparoscopic and retroperitoneoscopic techniques, for adrenalectomy. We discuss epidemiological trends, pathophysiological considerations, risk factors, clinical presentation, diagnostic strategies, and the evolution of surgical management, with an emphasis on recent advances, outcomes, and guideline-driven best practices. The article aims to provide clinicians with an up-to-date, mechanism-based understanding of endoscopic adrenal surgery to inform practice and optimize patient outcomes.

Introduction

Adrenalectomy is indicated for a spectrum of adrenal pathologies, including hormonally active tumors, incidentalomas, and malignancies. The adoption of endoscopic approaches—principally laparoscopic transperitoneal and posterior retroperitoneoscopic adrenalectomy—has supplanted open techniques in most elective settings due to superior perioperative profiles and improved recovery. This review synthesizes current literature to guide clinicians in selecting and executing the optimal surgical approach for adrenal lesions.

Epidemiology / Disease Burden

Adrenal masses are found in up to 4% of abdominal imaging studies, with a prevalence increasing with age. Most lesions are benign and nonfunctioning, but approximately 15-20% are hormonally active, necessitating surgical intervention. The incidence of adrenalectomy has increased, paralleling enhanced detection of adrenal incidentalomas. Pheochromocytomas, aldosteronomas, and adrenocortical carcinomas remain principal indications for surgical removal. The burden of disease underscores the importance of safe and effective surgical strategies, particularly as the population ages and imaging utilization rises.

Pathophysiology

Adrenal pathologies requiring surgery primarily include functional adenomas (producing aldosterone, cortisol, or catecholamines), nonfunctional adenomas with suspicious radiologic features, and primary malignancies. Functional tumors disrupt endocrine homeostasis through autonomous hormone secretion, leading to clinical syndromes such as Cushing’s, Conn’s, or pheochromocytoma. Malignant lesions may exhibit local invasion or metastasis, necessitating timely resection. Understanding tumor biology and hormone excess mechanisms is critical for surgical planning and perioperative management.

Risk Factors

Risk factors for adrenal neoplasms include genetic syndromes (e.g., MEN1, MEN2, von Hippel-Lindau disease), family history, advanced age, hypertension, and metabolic syndrome. Chronic ACTH stimulation, prior malignancies, and certain environmental exposures have also been implicated. Identification of risk factors aids in patient selection, surveillance, and surgical decision-making, particularly for incidentally discovered lesions.

Clinical Features

Clinical manifestations of adrenal tumors are determined by hormonal activity and mass effect. Functional tumors present with features of hormone excess: hypertension, hypokalemia (aldosteronoma), Cushingoid features (cortisol-producing adenoma), or paroxysmal hypertension, palpitations, and diaphoresis (pheochromocytoma). Nonfunctional tumors are often asymptomatic and detected incidentally. Large or malignant lesions may cause flank pain, fullness, or symptoms from local invasion. Thorough clinical assessment is essential for appropriate workup and operative planning.

Diagnosis

Diagnosis involves biochemical evaluation to assess hormonal activity, including aldosterone-renin ratio, dexamethasone suppression testing, plasma metanephrines, and catecholamines. Imaging modalities such as CT and MRI characterize lesion size, morphology, and invasiveness. Functional imaging (e.g., MIBG, PET) may be employed for indeterminate or metastatic lesions. Preoperative assessment also includes evaluation of surgical risk based on comorbidities and tumor characteristics, guiding the choice of endoscopic approach.

Treatment & Management

Endoscopic adrenalectomy is the standard of care for most benign and select malignant adrenal tumors, offering reduced morbidity, shorter hospital stay, and faster return to normal activity compared to open surgery. The laparoscopic transperitoneal approach provides wide exposure and is favored for larger tumors, while the retroperitoneoscopic approach offers direct access with less manipulation of intra-abdominal organs, reducing postoperative pain and ileus. Preoperative preparation, especially for pheochromocytoma (alpha-adrenergic blockade), is crucial. Intraoperative considerations include meticulous dissection, early adrenal vein control, and avoidance of tumor rupture. Conversion to open surgery may be necessary for technical difficulty or oncologic concerns.

Recent Advances / Emerging Therapies

Robotic-assisted adrenalectomy, single-site surgery, and mini-laparoscopic techniques represent evolving modalities aimed at further reducing invasiveness and enhancing precision. Robotic platforms offer improved dexterity, visualization, and ergonomics, particularly in complex or obese patients, albeit with increased cost and operative times. Image-guided navigation, intraoperative ultrasound, and enhanced recovery protocols are being integrated to optimize outcomes. Oncologic outcomes for minimally invasive resection of selected adrenocortical carcinomas and large tumors are being actively investigated, with early data suggesting feasibility in high-volume centers with rigorous patient selection.

Guideline Recommendations

Current guidelines from the European Society of Endocrine Surgeons (ESES), Endocrine Society, and American Association of Clinical Endocrinologists (AACE) endorse minimally invasive adrenalectomy for lesions <6 cm with benign radiological appearance and no evidence of local invasion. Open resection is reserved for suspected adrenocortical carcinoma, large invasive tumors, or cases with significant local adhesions. Laparoscopic and retroperitoneoscopic approaches are both acceptable; selection should be tailored to tumor size, location, patient anatomy, and surgeon expertise. Preoperative hormonal workup and perioperative management according to best practice guidelines are emphasized to minimize complications.

Conclusion

Endoscopic adrenalectomy has become the preferred technique for most adrenal tumors, offering substantial perioperative and postoperative benefits over open surgery. Advances in technology and perioperative care continue to expand the indications and safety profile of minimally invasive adrenal surgery. Rigorous patient selection, adherence to guidelines, and multidisciplinary collaboration are imperative to optimize outcomes. Ongoing research into robotic and image-guided techniques promises further refinement, but open surgery remains essential for complex or malignant cases. Clinicians must remain abreast of evolving evidence to deliver personalized, safe, and effective care for patients with adrenal disease.