https://orcid.org/0000-0001-8778-4415
Abstract
An interparietal hernia (IPH) involves the invasion of the hernia sac into various muscle layers and the fascia of the abdominal wall. An 82-year-old man presented with lower abdominal pain lasting 2 weeks. Computed tomography (CT) scans suggested IPH, and the patient then underwent elective surgery. Intraperitoneal findings showed a bilocular interstitial hernia, with the hernial sac extending from between the transverse abdominis and internal oblique muscles into the inguinal canal, and an internal inguinal hernia. The transabdominal preperitoneal repair (TAPP) method was used to repair the hernias. With recent improvements in the diagnostic accuracy of abdominal CT scans and the widespread use of laparoscopic surgery, reports of inguinal IPH repairs have been increasing. In cases with complex hernial sacs, such as that presented herein, the TAPP method is useful for accurately diagnosing and identifying the hernial orifice.
Introduction
Interparietal hernia (IPH) is a rare hernia type in which the sac extends into various anatomical layers and the fascia of the abdominal wall within the inguinal region [1]. Bartolin first reported IPH in 1661, which was subsequently defined into three types by Lower et al. [1] as preperitoneal, interstitial, or superficial. Reports of IPH in Japan have become more frequent as laparoscopic hernia repairs have become more common.
Herein, we report a case of simultaneous left internal inguinal hernia and bilocular left inguinal IPH that was successfully repaired using the transabdominal preperitoneal repair (TAPP) method.
Case presentation
An 82-year-old man presented to the emergency department with complaints of lower abdominal pain during the 2 weeks prior to his visit. He was taking oral medication for hypertension, which was well-controlled. Although the patient’s abdominal pain intensified the day prior to his presentation, it showed improvement at the time of initial evaluation. Upon physical examination, a bulge was noted in the left groin while standing, suggesting a spontaneous reduction of the incarcerated left inguinal hernia. Computed tomography (CT) of the abdomen and pelvis conducted on the day of presentation showed two hernia sacs (Fig. 1). One of these appeared to be an internal inguinal hernia medial to the inferior epigastric artery and vein. The lateral hernia sac with a prolapsed small bowel did not run through the inguinal canal. The patient was suspected of having a left inguinal IPH concomitant with an internal inguinal hernia and then underwent elective surgery. A laparoscopic examination of the abdominal cavity showed two hernias (Fig. 2). Visualization of the orifices through a peritoneal incision indicated one internal and one lateral inguinal hernia. The lateral inguinal hernia contained a hernia sac extending toward the inguinal canal located between the transverse abdominis and internal oblique muscles. Based on these findings, the patient was diagnosed with a bilocular interstitial hernia concomitant with an internal inguinal hernia, which was repaired using the TAPP method. The patient was discharged 2 d after surgery and has remained recurrence- and adverse event-free for >9 months after the repair.
CT images. The hernia sac is seen on the lateral (arrowhead) and medial (arrow) sides of the inferior epigastric artery and vein on the axial view. The lateral hernia sac (arrowhead) is observed outside the inguinal canal with the prolapse of the small intestine on the sagittal view.
Intraoperative findings peritoneal dissection showed an internal inguinal hernia with a hernia orifice lateral to it. From the lateral hernia orifice, one hernia sac extends toward the inguinal canal, and one extends between the transverse abdominis and internal oblique muscles. Mesh repair was performed on both hernia orifices.
Discussion
A rare hernia in which the sac extends into various anatomical layers as well as the fascia of the abdominal wall within the inguinal region, IPH is classified into three types depending on the layers involved: (i) preperitoneal, prolapse between the peritoneum and transversus fascia (20%); (ii) interstitial, prolapse between the transversus abdominis and internal oblique or internal and external oblique muscles (60%); and (iii) superficial, prolapse between the external oblique muscle and skin (20%) [1, 2]. The etiology of IPH is thought to be both mechanical and congenital [1]. Mechanical causes include obstruction of the inguinal canal by undescended testicles, causing an IPH (abdominal wall hernia) in each anatomically vulnerable layer as the hernia sac progresses [3]. In congenital hernias, the absence or narrowing of the external ring may be responsible for arresting the hernia in its usual path [4, 5]. IPH may not always result from a single factor and may involve multiple factors.
Differentiating the type of IPH based on physical findings alone is often difficult. In some cases, CT scans may be inadequate, with poor negative predictive value for the presence of various types of hernias [4]. However, with the recent increase in reported IPH cases, awareness and a better understanding of the anatomy of IPH have led to cases in which preoperative diagnosis using CT scans, especially sagittal images, is possible [5–7].
Treatment methods for IPH include the TAPP and anterior approaches. The TAPP method may be inadequate to diagnose IPH if the periphery of the hernia sac is not identified, which may occur because of the circular incision made in the peritoneum [3]. The TAPP method is useful for cases of complex IPH, such as bilocular hernias. It is also helpful for cases complicated by the presence of other inguinal hernias, including occult hernias, such as internal inguinal and femoral hernias [7]. An intraperitoneal approach facilitates repair similar to that of hernias with the internal inguinal ring as the hernial orifice. Therefore, the TAPP method facilitates simple and rapid exposure of the hernial orifice, potentially enabling more reliable reinforcement with surgical mesh.
In Japan, 23 cases of adult IPH have been reported by the nonprofit organization, Japan Medical Abstract Society, 10 of which were bilocular, including the present case (Table 1). The median age was 77 years (range, 59–89) [8–15], and males predominated (eight men and two women). Of the bilocular cases, the IPH type was interstitial in eight and superficial in two cases. All the patients underwent preoperative CT, and preoperative diagnoses were made in eight cases. Treatment strategies included TAPP in eight cases and an anterior approach in two cases, one of which required laparoscopic observation. In that case [12], only laparoscopic observation was conducted due to difficulties in pre-operative diagnosis and the inability to perform surgery under general anesthesia. After confirming the diagnosis of IPH, surgery was performed via an anterior approach.
Ten cases of bilocular IPH in Japan
| Author/publication year | Age | Sex | Site | Symptom | IPH type | Treatment |
|---|---|---|---|---|---|---|
| Yamamoto et al. [8] | 73 | Man | Right | Swelling, pain | Interstitial | TAPP |
| Murao et al. [9] | 77 | Woman | Bilateral | Pain | Right: interstitial+femoral hernia Left: interstitial+femoral, obturator hernia | TAPP |
| 71 | Man | Left | Groin mass | Interstitial | TAPP | |
| Kano et al. [10] | 77 | Man | Left | Swelling | Interstitial | TAPP |
| Taira et al. [11] | 59 | Man | Left | Swelling | Superficial | TAPP |
| Hirajima et al. [12] | 77 | Man | Left | Swelling | Interstitial | Laparoscopic observation ⇒ Direct Kugel |
| Kobayashi and Takagawa [13] | 75 | Man | Right | Swelling | Interstitial+internal inguinal hernia | TAPP |
| Takayama [14] | 89 | Woman | Left | Pain | Interstitial | Lichtenstein |
| Matsuoka et al. [15] | 86 | Man | Right | Pain | Superficial | TAPP |
| Our case, 2025 | 83 | Man | Left | Swelling, pain | Interstitial + internal inguinal hernia | TAPP |
IPH: interparietal hernia, TAPP: transabdominal preperitoneal repair
As laparoscopy facilitates accurate visualization of the hernial orifice and the direction of hernia sac progression, with a high possibility of identifying occult hernias, TAPP is extremely useful for the treatment of IPH.
Conflicts of interest
The authors declare no conflicts of interest for this article.
Funding
None declared.
Data availability
Data sharing is not applicable to this article, as no datasets were generated or analyzed in the current study.
Ethics statement
Written informed consent was obtained from the patient for the publication of this case report and any accompanying images.
