Histology of the parietal peritoneum: a systematic review of the microstructural basis of the preperitoneal (deep rectus sheath) block

This project aims to conduct a systematic review investigating the histological and microanatomical characteristics of the abdominal parietal peritoneum, in animal models and also in humans, with particular focus on structures relevant to the pre-peritoneal (deep rectus sheath) block. The pre-peritoneal block involves the injection of local anesthetic into the tissue plane between the posterior rectus sheath and the abdominal parietal peritoneum. Although this technique has been increasingly described in clinical practice for abdominal wall and peri-visceral analgesia, the micro-structural features of the parietal peritoneum and the adjacent pre-peritoneal space remain incompletely characterized, in particular the autonomic innervation. This systematic review will synthesize evidence from histological studies (animal and human), cadaveric dissections, and experimental investigations examining the micro-anatomy, innervation, vascularization, connective tissue architecture, and structural organization of the abdominal parietal peritoneum. Particular attention will be given to studies describing nerve fibers, nociceptive pathways, and tissue interfaces that may contribute to the mechanism of action of local anesthetic deposited in the pre-peritoneal plane. The goal of this project is to provide a comprehensive synthesis of the micro-structural basis underlying the pre-peritoneal (deep rectus sheath) block, improving the anatomical understanding of this regional anesthesia technique and supporting its rational clinical application.