A fascial reinterpretation of the classical female pelvic surgical anatomy: seeing things from a different angle.

STUDY OBJECTIVE The classical surgical anatomy of the female pelvis was born with radical hysterectomy [1] and focused on the pivotal role of the lateral parametrium, a conceptually complex structure, artifact of surgical anatomy [2] , without which, the whole classical model would collapse. Here, using natural planes, we tried to simplify the puzze of virtual spaces surrounding this structure [ 3 , 4 ]. With the aim of better conceptualizing the classical model of female pelvic surgical anatomy, we broadened its perspective, narrowed on the historical gynecological setting, by developing a comprehensive model of pelvic retroperitoneal compartmentalization. This dissection was based on invariable anatomical (fasciae), rather than surgical-anatomical (parametrium) structures and aims at providing a holistic, more user-friendly approach, intended for surgical and educational purposes [5] . As each compartment has its own surgical function (hence the name), the excavation of a single compartment may be used as a rational guide to tailor surgery to the site of the pathology to be treated or the type of procedure required; while their sequential development may be useful in planning surgical strategies. Redefining the classical model according to the anatomical fascial planes of dissection, potentially allows for an intrinsic surgical reproducibility, minimizing dissective bias. A reinterpretation of known anatomy is required to enhance education. The breaking down of such a complex system (the pelvis) into smaller parts (compartments) will hopefully provide a useful guide to conceptualize and navigate; surgical navigation requires a holistic mental map and a few invariable anatomical reference points or landmarks. DESIGN a step-by-step laparoscopic demonstration of the fascial model, developed on a fresh frozen female pelvis and its correlation with the classical female retroperitoneal surgical anatomy.. SETTING Cadaver Lab, Legal Medicine, University of Turin. INTERVENTIONS The first part of the video shows the progressive development of the three hemi-compartments in the right hemipelvis and of the fourth median compartment, after the identification of three invariable anatomical reference points: the obliterated umbilical artery, the ureter and the sacrouterine ligament as superficial landmarks of 3 deeper fascial-ligamentous structures: the umbilicovesical fascia, the urogenital-hypogastric fascia, the sacropubic ligament, respectively. The areas delimited by the aforementioned deep fascial ligamentous structures have been called compartments: - the right parietal hemi-compartment, as it is bordered by the sidewall of the pelvis, laterally to the umbilicovesical fascia - the right vascular hemi-compartment, so-called because of the presence of the internal iliac vessel visceral branches, between the umbilicovesical fascia and the urogenital-hypogastric fascia - the visceral compartment, as it contains the pelvic organs, between the sacropubic ligaments - the right neural hemi-compartment, because of the presence of the organ-specific vegetative bundles, medially to the urogenital-hypogastric fascia. The second part of the video describes the retrorectal, presacral and retropubic connection areas between the neural, vascular and parietal hemi-compartments of each hemipelvis, justifying their overall crescent shape. Lastly, the spaces of classical surgical anatomy included in each hemi-compartment are listed not only according to their anatomical but also functional criterion. In fact, the parietal compartment should be developed for the evaluation of pelvic lymph node status or during exenterative and urogynecological procedures. The vascular compartment must be prepared when sectioning of the vascular visceral pedicles at their origin is required. Development of the neural compartment is required whenever visceral neural components are to be spared. The visceral compartment has to be developed for a complete organ mobilization and exposure. CONCLUSION Taken as a whole, our four-compartment model of pelvic anatomical surgery is intended for use in planning and optimizing surgical strategies. Moreover, it is potentially able to simplify surgical teaching and training, allowing to fit puzzle-like pieces of disjointed organ-specific retroperitoneal spaces together, according their function. Correlation of this approach to clinical outcomes is still being determined.