The anatomy of the male inferior hypogastric plexus: What should we know for nerve sparing surgery.

The aim of this study was to investigate the nerve supply to the structures in the male lesser pelvis and review its clinical relevance, especially during nerve sparing surgery. Three formalin-embalmed and 16 Thiel-embalmed male hemipelves were used. They were microdissected after repeated treatments with nitric acid diluted 1:10 with milliQ-water. The inferior hypogastric plexus (IHP) is a fan-like structure lateral from the rectum on the fascia of the levator ani. Nerves emerging from the proximal, solid part of the plexus follow the internal iliacal vessels and reach the prostate from dorsolateral. The innervation of the urethra and the corpora cavernosa derives from two origins: one follows the ejaculatory duct and the seminal vesicle, reaching the proximal urethra and the prostate from dorsal; the other follows the inferior vesical artery to reach the prostate from lateral, and then forms the neurovascular bundle on both sides of the prostatic fascia, spreading to the pelvic floor muscles and the corpora cavernosa along with the distal urethra. A connection between the two parts was demonstrated in approximately one third of the samples investigated. The nerve supply to the urinary bladder, the urethra, and the corpora cavernosa emerges mainly from the IHP. The innervation of the proximal urethra and its autonomic muscular structures has a dorsal (ejaculatory duct) and lateral (inferior vesical artery) origin. To maintain good erectile and continence function it is important to save both the dorsal and lateral neurovascular roots. Clin. Anat. 31:788-796, 2018. © 2018 Wiley Periodicals, Inc.

Combined maceration procedure permits advanced microsurgical dissection of Thiel-embalmed specimens.

INTRODUCTION: Due to the realistic colour, texture conservation and preservation of biomechanical properties, Thiel-embalming is becoming the main embalming procedure for clinical courses and research based on human cadaver material. The aim of this study is to establish a new procedure that allows advanced microdissection of small vessels and intraorganic nerves in Thiel-embalmed material. MATERIAL AND METHODS/RESULTS: After a classical gross anatomical dissection, human hemipelves underwent repetitive application of 3 consecutive steps: (i) maceration with alloy of nitric acid and MiliQ water 1:10 for 24-48h. (ii) Immersion: the hemipelves were rinsed under tap water for 20-30min. and placed in a water bath for 1h. The nerves become more prominent due to the swelling and increased water content. (iii) microdissection under surgical microscope. To facilitate the organ visualization perfusion with polyurethane (Pu4ii, VasQtec®, Switzerland) in red/blue for arteries/veins respectively has been performed. CONCLUSION: By using the proposed procedure, we performed satisfactory microdissection on Thiel-embalmed samples. The combination with polyurethane vascular casting permits visualization of small arterioles and venules in a range of 20-25µm. The method is very suitable for demonstration of somatic and vegetative nerves. Branches of the sacral plexuses and autonomic nerves from the superior and inferior hypogastric plexus have been tracked up to the smallest intraorganic branches in a range of 12.5-15µm. In conclusion, the established combined procedure offers a new possibility for advanced microdissection, which will allow acquisition of clinically relevant information about organ specific micro- vascularization and innervation.