Significance of the Pseudosac During Inguinal Hernia Repair

Inguinal hernia repair is one of the most common general surgical procedures in Western countries, with the laparoscopic approach widely adopted for its reduced pain and faster recovery [1]. The inguinal canal is a deceptively complex anatomical tunnel which transmits the spermatic cord or round ligament through the lower abdominal wall, and thus is predisposed to hernia formation. Indirect hernias are characterised by a true peritoneal sac which protrudes into the deep ring, whereas direct hernias emerge through a weakness within Hesselbach's triangle bordered by the rectus abdominis medially, the inferior epigastric vessels laterally and the inguinal ligament inferiorly [2]. Within the preperitoneal space (accessed via the totally extraperitoneal [TEP] or transabdominal preperitoneal [TAPP] approach) a highly reliable sign of a direct hernia is the pseudosac. This is a localised thickening of transversalis fascia which we conceptualise as a ‘reverse sac’ since it reduces anteriorly instead of posteriorly as observed with a true peritoneal sac of an indirect hernia. The pseudosac of a direct hernia is a significant but often under-recognised structure which confirms a medial defect [3]. As a teaching point for trainees, this can and should be identified early in the procedure even prior to commencing dissection (Figure 1) and enables the operator to distinguish between direct and indirect hernias with confidence. Misidentifying a pseudosac for a peritoneal sac may lead to unnecessary dissection or inadvertent injuries. A prominent pseudosac can obscure deeper structures such as Cooper's ligament, the pubic tubercle or the medial edge of the internal ring. This becomes particularly important in bilateral repairs, recurrent hernias, or patients with distorted anatomy where traditional landmarks may be obscured. Intraoperatively, precise blunt dissection is generally sufficient to separate the pseudosac from surrounding preperitoneal tissues, particularly when it is clearly delineated and not densely adherent. In cases where the pseudosac is thin-walled, collapsed and non-prominent following reduction, no further intervention is usually required. However, when the pseudosac is broad-based or redundant, it may contribute to a persistent dead space and predispose to postoperative seroma or bulging. In this scenario, plication using intracorporeal sutures or an Endoloop can be employed to invert and flatten the pseudosac against the posterior wall. Alternatively, it may be inverted and fixed with a suture or tack to Cooper's ligament or the pubic tubercle. Surgeons must be aware of the potential tack-related risks of neurovascular or bony irritation and chronic pain [4, 5]. These manoeuvres obliterate the potential dead space and also reinforce the medial compartment, which is most vulnerable to recurrence. Excision or fenestration of the pseudosac is rarely indicated and is generally reserved for cases where the tissue is fibrotic, thickened or contributes to a palpable bulge that cannot be adequately addressed by plication [6]. Without careful reduction or management of the pseudosac, mesh placement may be compromised particularly in the medial compartment. The importance of achieving broad, tension-free mesh coverage cannot be overstated as this remains a critical determinant in the long-term durability of inguinal hernia repair [7]. Early intraoperative identification of a ‘reverse sac’ or pseudosac is therefore a critical step. If inadequately addressed, it may contribute to medial recurrence, become a seroma cavity or cause postoperative bulges misinterpreted as recurrence [4, 6]. For all skill levels, it serves as a tangible, reproducible structure that reinforces key anatomical concepts such as the boundaries of the myopectineal orifice, the role of transversalis fascia in hernia formation and the three-dimensional nature of the inguinal region [7]. Mina Sarofim: visualization, writing – review and editing, conceptualization. Nimalan Pathma-Nathan: supervision. The authors have nothing to report. Open access publishing facilitated by The University of Sydney, as part of the Wiley - The University of Sydney agreement via the Council of Australasian University Librarians. The authors have nothing to report. Intraoperative photographs used with patient consent. The authors declare no conflicts of interest. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.