Virtual reality and robotic technologies in adrenal surgery

Abstract

Despite the introduction of laparoscopy, which has revolutionized the practice and concepts of adrenal surgery, several issues still need to be addressed. For instance, in many cases, current diagnostic tools do not allow the accurate prediction of the risk of malignancy in pheochromocytomas; in addition, adrenocortical carcinoma is very rarely diagnosed at an early and potentially curable stage. These limitations become even more important in the era of laparoscopic adrenalectomy since adrenal cancer is considered an absolute contraindication for a laparoscopic approach due to the risk of dissemination. Although recent reports suggest that fears about the oncologic inadequacy of laparoscopic adrenalectomy might be unjustified [1], there is no question that operating an adrenal cancer laparoscopically is much more challenging than operating on a small benign lesion. The surgeon would ideally like to know about the presence of a cancer prior to operation. Furthermore, even the most experienced surgeon would agree that vena caval invasion contraindicates a laparoscopic approach. Unfortunately, this prediction is not possible in all patients. The management of adrenal incidentalomas is also controversial. Incidentalomas have a frequency of about 1.3% of all patients undergoing abdominal computerized tomographic examinations; this incidence rises to 8% in necropsy series. The incidence of adrenocortical carcinoma, however, is extremely rare at about 1/800,000. Larger adrenal lesions are associated with increased risk of cancer,and incidentalomas larger than 6 cm should be removed; there is general consensus that tumors smaller than 3 cm do not represent an indication for surgery,whether the operation is performed laparoscopically or not.However,there is a tendency to consider the decreased invasiveness of laparoscopic surgery as an argument to broaden surgical indications for smaller sized incidentalomas. Miccoli et al. [2] documented an increase in the number of patients referred for adrenalectomy after the introduction of laparoscopic adrenalectomy,and,in particular more patients were referred who had adrenal metastases and incidentalomas. Is it justifiable to operate on patients with/and for smaller incidentalomas? Proponents of this strategy argue that this may be the only way to "pick up" adrenal cancers at an earlier stage, and that the minimally invasive removal of an adrenal mass may be preferable to lifelong follow-up, where the likelihood of malignancy is assessed by size on CT scanning, a somewhat arbitrary approach. Furthermore, different size criteria have in fact been used when determining surgical indications in different centers. Importantly, some reports suggest that the cross-sectional anatomy represented by 2-dimensional CT studies may be inaccurate and therefore result in an inadequate estimation of the actual adrenal size and surgical indications which may be inappropriate for the individual patient [3-5].Thus, better criteria for establishing when incidentalomas should be removed are highly desirable. There are, in addition, technical issues about adrenal surgery for consideration. Since the initial report by Gagner in 1992 [6],laparoscopic adrenalectomy has rapidly become the surgical procedure of choice for the treatment of benign adrenal lesions. However, la-paroscopic adrenalectomy can at times be challenging. This is the case in obese patients,where even tumoral glands may be very difficult to identify. Previous surgery on the kidney,pancreas,or spleen may render the transperitoneal approach challenging especially for surgeons with limited laparoscopic experience.In general, the advent of minimally invasive techniques has further emphasized the importance and potential danger to patients of the learning curve in surgery, creating a need for alternative training models and improvement in surgical education to enhance patient safety. The introduction of new technologies may possibly help surgeons address and hopefully solve many of the issues mentioned. In recent years, computer-based image acquisition modalities have matured to the point that they are now capable of accurate 3D reconstructions of an organ system or body region.The advantages of these virtual reality (VR) systems consist in the creation of a virtual environment where complex structures are represented in a fully 3-dimensional manner, which gives the surgeon the ability to interact with the image as if it truly exists, understanding the anatomy of a structure, the features of a lesion,performing tasks and manipulations, as well as navigation within the lumen of blood vessels.