2.1 Patients
One hundred fifty-six patients with ventral hernia (including 12 cases combined with diastasis recti or only diastasis recti) who were recommended to undergo ESR in ten Chinese hospitals between March 2016 and July 2019 were included. Patient distribution was as follows: East Hospital affiliated to Tongji University (n = 30), Shanghai General Hospital (n = 22), Northeast International Hospital (n = 21), Linzi District People's Hospital (n = 25), Shengjing Hospital (n = 15), The First Hospital affiliated to Fujian Medical University (n = 14), Sir Run Run Shaw Hospital (n = 10), The University of Hong Kong-Shenzhen Hospital (n = 8), Weihai Central Hospital (n = 6), and Putuo Hospital (n = 5). The qualifications of the surgeons included experience with >500 inguinal hernia TEP or TAPP repairs, 50 Lap-IPOM and 50 open sublay repairs, and 5 ESRs.
2.2 Surgical procedure and technical points
2.2.1 Trocar layout
In addition to following the basic principles of the trocar layout for routine endoscopic surgery, the defect location and the dissection plane should also be considered when positioning the trocars in ESR. Specifically, in the TES procedure, the camera and the operating trocar should first be placed where the sublay plane is easy to establish. After the establishment of part retromuscular space, more operating trocars are placed at appropriate locations. The trocar layout for different defect is relatively dynamic. In this article, we summarize the typical trocar layouts for various defect regions (Figures 1 and 2). The camera trocar and the surgeon trocars can be switched when necessary.
2.2.2 The separation of the sublay plane
The sublay plane is also called the retromuscular space which includes the lateral space between the transversus abdominis and the peritoneum and the medial space between the rectus abdominis and the peritoneum.
During ESR surgery, two planes where the posterior sheath exists can be dissected: the space anterior to the sheath and the space posterior to the sheath. The former space, also called the retro-rectus space, is the one most commonly used because it is easy to access and separate. Frequently during the TES procedure, after the retro-rectus space is accessed, a 10-mm trocar is placed in front of the posterior sheath (Figures 3A) or directly in the extraperitoneal space above the pubis (Figures 3b). Then, blunt dissection using the camera is performed to obtain more space. Afterward, several 5-mm trocars are placed in appropriate locations for further separation.
Anatomically, both the medial and lateral retromuscular spaces and the retro-rectus space on both sides are separated by several natural anatomic partitions and can be connected by breaking one or more of these partitions. So, referring to the partitions, we redivide the spaces of this plane into four regions (Figure 4). We call the procedure of connecting the separated spaces by breaking partitions the “partition breaking” technique. First, the posterior sheath and the transversus abdominis behind are the partitions between Region I and the upper part of Region II “partition breaking here is carried out by cutting Line A (Figure 3c and d, this step is also called endoscopic transversus abdominis release (eTAR) (28)). Second, the skill of entering from Retzius space (Region III) to Bogros space (lower part of Region II) is precisely the same as that in TEP for inguinal hernia (breaking Line C). Third, “partition breaking for connecting Region I on both sides is carried out by cutting off Line B and then dissecting Region IV to detach the extraperitoneal fat from the linea alba (Figure 3e). The step performed from one side to another is called “crossover” (Figure 3f). Consequently, the anterior sheath of both sides is still connected with the linea alba, which is crucial for preserving the integrity of the anterior abdominal wall (Figure 3g and h). Additionally, the hernia ring and the umbilicus are both partitions too. The hernia sac reduction is easy (Figures 3i) for primary ventral hernias but difficult for incisional hernias. The umbilicus or the sac is usually transected around the umbilicus orthe hernia ring on the basis of the adhesions and scar in situ (Figures 3j). Damaging the hernia contents must be avoided. After partition breaking, a large sublay plane crossing several retromuscular regions is obtained for subsequent operation and mesh deployment.
Another retromuscular plane where the posterior sheath exists is the space posterior to the sheath (Figure 5a and b). Here the peritoneum is quite thin and difficult to separate (Figure 5b). The procedure is carried out by first creating a preperitoneal space above the pubis and then descending cephalad into the plane between the posterior sheath and the peritoneum, and further separating cranially and/or laterally (Figure 5c and d). This space also directly connects with the lateral retromuscular space and then the retroperitoneum. Anatomically, the peritoneum is just like an eggshell membrane wrapping all abdominal viscera. The peritoneum on all sides, from bottom to top and from anterior to posterior, is connected and forms a whole visceral sac. Therefore, the technique of separating the whole visceral sac at this plane is called “the total visceral sac separation (TVS), which was first proposed and implemented by Dr. Jiang HY(26). It is a brand-new technique and will be illustrated in Discussion (Section 4).
The procedure for TAS is similar to that for the inguinal hernia TAPP. After entering the abdominal cavity, adhesiolysis is performed first (Figure 6a). The peritoneum (mostly along with the posterior sheath) is then opened at least 5 cm away from the defect (Figure 6b). The retromuscular space is further separated (Figure 6c), and the range of separation includes the defect and at least 5 cm away from its margin.
2.2.3 Management of the defect
After space separation, the open peritoneum (Figure 3k) or the peritoneum with the posterior sheath is closed with a continuous suture (Figure 3l). The closure of the posterior sheath is not obligatory and is only implemented with low tension. Defect should be closed except few minor defects. The defect can be closed with either continuous suture with barbed or polyester thread (Figure 3m) or interrupted transfascial suture with a suture passer (Figures 3n and 6d).
2.2.4 Mesh deployment and fixation
After defect closure, a mesh is introduced into the separated space. The size of the mesh is related not only to the size of the defect but also to the range of the separation so that it can cover as much of the separated sublay plane as possible. At the maximum, when bilateral TAR was performed for a large midline defect, the mesh size would reach 30 × 35 cm; at the minimum, the mesh should cover not less than 5 cm away from the defect margin. The mesh can be placed without fixation (secured by just the abdominal pressure, sometimes with the central position; Figure 3o) or with fewer points of fixation by glue (Figure 3p), transfascial suture, or tackers. Self-adhesive mesh is also a good option (Figure 3q). When a relatively small mesh is used, for example, if limited space is separated during TAS, the mesh should be fixed with multipoint transfascial sutures or tackers (Figure 6e). A polypropylene mesh is used in most cases. Both normal-weight and light-weight mesh, including some partially absorbable meshes, are selected. If there are several points of small peritoneal damage, an anti-adhesion mesh is preferred.
2.2.5 Drainage and peritoneum closure
Closed drainage should be placed for patients with a large separated space, especially for the TES procedure (Figure 3p). The peritoneal flap is closed with a continuous suture at the end of the TAS procedure (Figure 6f).
2.3 Data collection and follow-up
Surgical information, postoperative recovery, and short-term (within 1 month) and long-term (after 1 month) postoperative complications were carefully collected for further evaluation.
Each patient came to the clinic at 2 and 8 weeks, 6 months, and 1 year after surgery. After that, telephone interviews were conducted every half year, and patients with complaints visited the clinic to be checked for possible complications. Chronic pain was defined as sustained pain or discomfort that lasted >3 months. The follow-up data collection was halted in October 2019, and the duration of follow-up ranged from 3 to 45 months (median 12 months; interquartile range [IQR] 5–21 months). One patient was lost to follow-up within 1 year, and five patients were lost to follow-up after 1 year.
2.4 Statistical analysis
Qualitative data are expressed as percentage (%), and quantitative data as mean ± standard deviation or median (min–max) (IQR) concerning their distribution. Statistical assessments were conducted using Excel 2010.