Journal of Clinical Medicine Article Embryological Development and Topographic Anatomy of Pelvic Compartments—Surgical Relevance for Pelvic Lymphonodectomy Andreas Bayer 1,†, Tillmann Heinze 1,† , Ibrahim Alkatout 2,*, Daniar Osmonov 3 , Sigmar Stelzner 4 and Thilo Wedel 1,* 1 Kurt Semm Center for Minimally Invasive and Robotic Surgery, Center of Clinical Anatomy, Institute of Anatomy, Kiel University, 24098 Kiel, Germany; [email protected] (A.B.); [email protected] (T.H.) 2 Kurt Semm Center for Minimally Invasive and Robotic Surgery, Department of Obstetrics and Gynecology, Campus Kiel, University Hospital Schleswig Holstein, 24105 Kiel, Germany 3 Kurt Semm Center for Minimally Invasive and Robotic Surgery, Department of Urology, Campus Kiel, University Hospital Schleswig Holstein, 24105 Kiel, Germany; [email protected] 4 Department of General Surgery, Hospital Dresden-Friedrichstadt, 01067 Dresden, Germany; [email protected] * Correspondence: [email protected] (I.A.); [email protected] (T.W.); Tel.: +49-431-500-21450 (I.A.); +49-431-880-2489 (T.W.) † Contributed equally to the study. Abstract: Background: The oncological outcome of surgery for the treatment of pelvic malignancies can be improved by performing pelvic lymphonodectomy. However, the extent and regions of lymph node harvest are debated and require profound knowledge of anatomy in order to avoid collateral damage. Methods: The embryological development and topographic anatomy of pelvic compartments in relation to pelvic lymphonodectomy for rectal, uterine, and prostate cancer are Citation: Bayer, A.; Heinze, T.; reviewed. Based on pre-dissected anatomical specimens, lymph node regions and drainage routes Alkatout, I.; Osmonov, D.; Stelzner, S.; of the posterior and urogenital pelvic compartments are described in both genders. Anatomical Wedel, T. Embryological landmarks are highlighted to identify structures at risk of injury during pelvic lymphonodectomy. Development and Topographic Results: The ontogenesis of urogenital and anorectal compartments and their lymphatic supply are Anatomy of Pelvic key factors for adequate lymphonodectomy, and have led to compartment-based surgical resection Compartments—Surgical Relevance strategies. However, pelvic lymphonodectomy bears the risk of injury to somatic and autonomic for Pelvic Lymphonodectomy. J. Clin. nerves, vessels, and organs, depending on the regions and extent of surgery. Conclusion: Embryolog- Med. 2021, 10, 708. https://doi.org/ ically defined, compartment-based resection of pelvic malignancies and their lymphatic drainage 10.3390/jcm10040708 routes are based on clearly delineated anatomical landmarks, which permit template-oriented pelvic lymphonodectomy. Comprehensive knowledge of pelvic anatomy, the exchange of surgical concepts Academic Editor: Angelo Cagnacci Received: 19 November 2020 between specialties, and minimally invasive techniques will optimize pelvic lymphonodectomy and Accepted: 4 February 2021 reduce complications. Published: 11 February 2021 Keywords: pelvic compartments; embryologic development; oncologic surgery; pelvic lymphonodec- Publisher’s Note: MDPI stays neutral tomy; topographic anatomy; autonomic pelvic nerves; rectal cancer; uterine cancer; prostate cancer with regard to jurisdictional claims in published maps and institutional affil- iations. 1. Introduction 1.1. Lymphonodectomy Surgery for the treatment of malignant disease is not limited to the affected organ Copyright: © 2021 by the authors. alone. According to clinical guidelines across surgical specialties, surgery performed with Licensee MDPI, Basel, Switzerland. a curative intention consistently involves the removal of lymph nodes along lymphatic This article is an open access article drainage routes. Different types of lymphonodectomy (e.g., systematic, therapeutic, sen- distributed under the terms and tinel, sampling, debulking) have been described [1]. These are viewed as an integral part conditions of the Creative Commons of the surgical procedure and the overall therapeutic concept for the underlying malignant Attribution (CC BY) license (https:// disease. In radical surgery, the purpose of removing locoregional lymph node metastases creativecommons.org/licenses/by/ is to improve the prognosis of disease. Moreover, lymphonodectomy allows exact post- 4.0/). J. Clin. Med. 2021, 10, 708. https://doi.org/10.3390/jcm10040708 https://www.mdpi.com/journal/jcm J. Clin. Med. 2021, 10, x FOR PEER REVIEW 2 of 17 drainage routes. Different types of lymphonodectomy (e.g., systematic, therapeutic, sen- tinel, sampling, debulking) have been described [1]. These are viewed as an integral part J. Clin. Med. 2021, 10, 708 2 of 16 of the surgical procedure and the overall therapeutic concept for the underlying malig- nant disease. In radical surgery, the purpose of removing locoregional lymph node me- tastases is to improve the prognosis of disease. Moreover, lymphonodectomy allows exact postoperativeoperative staging staging of the of underlyingthe underlying malignant malignant disease disease and and provides provides a basis a basis for adjuvantfor adju- vanttherapy therapy [2,3]. [2,3]. Lymphatic drainagedrainage of of a a given given organ organ mainly mainly occurs occurs in centripetalin centripetal direction direction and and follows fol- lowsits blood its blood supply supply which, which, in turn, in turn, is determined is determined by the by embryologicalthe embryological development development of the of theorgan. organ. Therefore, Therefore, the the extent extent and and regions region ofs of lymphonodectomy lymphonodectomy must must bebe basedbased onon the ontogenesis of the affected organ as well as the corresponding anatomical compartment. This concept concept is is especially especially true true of of intrapelvic intrapelvic malignancies malignancies because because pelvic pelvic organs organs have have dif- ferentdifferent embryological embryological origins origins and and are arearranged arranged in predefined in predefined compartments. compartments. Figure Figure 1 pro-1 providesvides a summary a summary of major of major pelvic pelvic lymph lymph node node regions regions in the in thefemale female and and male male pelvis. pelvis. Figure 1. Schematic diagram of pelvic lymph node compartments.compartments. Mediolateral view of a right-sided male (A)) and female ((B)) hemipelvishemipelvis withwith pelvicpelvic organsorgans andand supplyingsupplying arteries.arteries. RegionalRegional lymph nodes are colored differently (inserted legend in (A). Modified according to the Committee on Classification of Regional Lymph Nodes of the Japan Society of Clinical in (A). Modified according to the Committee on Classification of Regional Lymph Nodes of the Japan Society of Clinical Oncology [4]. Oncology [4]. 1.2. Pelvic Compartments The pelvicpelvic cavitycavity is is subdivided subdivided into into two two (male) (male) or three or three (female) (female) compartments. compartments. While Whilethe posterior the posterior compartment compartment corresponds corresponds to the anorectum, to the anorectum, the anterior the compartmentanterior compart- com- prisesment comprises the bladder the and bladder the prostate/seminal and the prostate/sem vesiclesinal in vesicles males. Ininfemales, males. In the females, additional the additionalmiddle compartment middle compartment consists of the consists uterovaginal of the complexuterovaginal and thecomplex adnexa. and Based the onadnexa. onto- Basedgenetic on development, ontogenetic development, each of these compartmentseach of these compartments is marked by organ-specificis marked by organ-spe- lymphatic cificdrainage lymphatic routes, drainage which have routes, led towhich specific have surgical led to approachesspecific surgical for lymphonodectomy. approaches for lym- phonodectomy.Despite the diverse concepts and extent of pelvic lymphonodectomy propagated in colorectal,Despite the gynecologic, diverse concepts and urologic and extent cancer of surgery,pelvic lymphonodectomy similar technical challengespropagated are in colorectal,faced in all gynecologic, of these surgical and urologic specialties. cancer On surgery, the one similar hand, technical the removal challenges of lymph are nodes faced inshould all of bethese asradical surgical as specialties. necessary. On On the the one other hand, hand, the functional removal of and lymph structural nodes damage should beshould as radical be as as minimal necessary. as possible.On the other A prerequisitehand, functional for the and achievement structural damage of these should aims be is profoundas minimal knowledge as possible. of both,A prerequisite the ontogenetic for the and achievement topographic of anatomy these aims of pelvic is profound organs. Theseknowledge aspects of willboth, be the addressed ontogenetic in the and present topographic work by anatomy briefly recapitulatingof pelvic organs. embryologic These as- pectsorigins, will describing be addressed the in anatomical the present features work by of briefly each pelvicrecapitulating compartment, embryologic and surgicalorigins, concepts derived from these. Anatomical landmarks that must be preserved during pelvic lymphonodectomy are given special attention. Although the anatomical features apply to all types of surgery (open, laparoscopic, robot-assisted approaches), they are particularly important for minimally invasive techniques because the surgeon’s topographic orientation must be aligned to the limited