RoboTar

Rachel Alt MD, Francesca Lombardo MD, Joao Grossi MD, Conrad Ballecer MD, FACS
Rachel Alt MD
Maricopa Integrated Health System
Aaron Hechtman DO
Maricopa Integrated Health System
Francesca Lombardo MD
General Surgery Resident at Insubria University (Varese)
Joao Vicente Grossi MD
Department of General and Digestive Surgery at São Lucas Hospital of PUCRS – Porto Alegre – Brazil, Surgeon at Hospital Moinhos de Vento – Porto Alegre – Brazil
Conrad Ballecer MD, FACS
Co-director of the Center for Minimally Invasive and Robotic Surgery, Attending Faculty at Maricopa Integrated Health System

Abstract

Robotic ventral hernia repair, combining principles of laparoscopic and open ventral hernia repair, is an emerging approach to the management of ventral hernias. This technique has been growing in popularity for both large and small defects due to the enhanced 3D visualization, improved ergonomics and precise instrumentation. In this chapter, we will discuss the anatomical details and technical approaches of the robotic Transversus Abdominis Release (RoboTar or r-TAR).

Robotic transversus abdominis release (RoboTar or r-TAR)

Introduction

The Transversus Abdominis Release (TAR) is a form of posterior component separation first described by Novitsky et al (1). The tenets of the approach were designed to follow the principles put forth by Professors Rives and Stoppa for the treatment of large incisional hernias or those with lateral defects (2). The first step of the repair involves incision of the posterior sheath and subsequent dissection from the rectus abdominis muscle (3,4). This dissection plane is carried laterally to the linea semilunaris; entry into the pre-transversalis or preperitoneal plane is facilitated by division of the transversus abdominis muscle (5). These steps allow for the medialization of the recti muscles to reconstitute linea alba while creating an extraperitoneal plane for the placement of a large prosthetic; thereby reinforcing the entire visceral sac – giant prosthetic reinforcement of the visceral sac (6,7,8).

RoboTar adheres to the approach established by Novitsky et al., while bringing it into the realm of minimally invasive surgery. Though most recent reports have shown longer operative times with robotic TAR (r-TAR) compared to open approaches, this is expected due to inexperience with the technique. Indeed, operative times will continue  to decrease as surgeons gain experience until open versus robotic times will become nearly equivalent. The overall value of r-TAR could be established, with appropriate training, in terms of quality outcomes, shorter convalescence, patient satisfaction, and cost savings. Our experience with the use of robotics was associated with decreased intraoperative blood loss, fewer systemic complications, decreased wound morbidity, decreased postoperative pain, as well as decreased hospital length of stay and elimination of readmissions. Interestingly, there have been studies with encouraging results that included higher risk patients: BMI>30, Diabetes mellitus, and current tobacco use (9,10,11). Of note, the r-TAR can be performed in other countries with the learning curve similar to that found in other recent articles (12).

Preoperative considerations

Robotic retromuscular hernia repair employing the TAR for posterior component separation requires an extensive knowledge of the individual layers of the abdominal wall. Hernia repair by way of abdominal wall reconstruction and component separation should be regarded as the definitive repair for large hernias. Therefore, it is mandatory that surgeons performing RoboTar are not only experienced in the open counterpart, but also well experienced on the robotic platform.

Obtaining a thorough history and physical is mandatory to coordinate an operative plan. Specifically, co-morbidities such as diabetes, obesity, smoking, and collagen vascular disease may critically affect the operative plan. Preoperative optimization is vital to achieve a durable repair while minimizing the risks of postoperative complications (8,11). Although patients may not be able to reach the ideal BMI, they must show they are committed to making lifestyle changes and are willing to participate in their post-operative care.

A CT scan of the abdomen and pelvis is critical to preoperative planning; allowing for anatomic visualization, delineation of hernia defect, and evaluation for any previously placed mesh. The ideal candidates for r-TAR are patients with mid-abdominal wall defects measuring between 8 and 16 cm wide. Factors such as body habitus and abdominal wall compliance must be taken into account during preoperative evaluation. Additional indications for r-TAR include lateral defects such as ostomy site hernias, which require lateral overlap beyond the level of the linea semilunaris.

Relative contraindications to note when planning r-TAR include hernias with significant loss of abdominal wall domain, defects that extend from flank to flank, and significant dystrophic or ulcerated skin requiring excision.

Patient positioning, trocar placement and docking

For the majority of patients with large midline defects, supine positioning with the arms tucked is preferred. Trocars are placed in the lateral abdomen similar to conventional laparoscopic repair (Fig 1). Measures such as raising the kidney rest and or flexing the bed can increase the distance between the costal margin and the iliac crest to afford adequate space for trocar placement and separation. The use of bariatric length trocars is also helpful to minimize robotic arm collisions with legs or trunk. The robot is docked over the contralateral abdomen (Fig 2).

Figure 1 Port Positioning

Figure 2 Docking

Posterior sheath mobilization

After safe adhesiolysis, the hernia defect is evaluated and the rectus abdominis muscle is identified (Fig 3 a-d). It is not necessary to dissect the hernia sac unless this tissue will be required to achieve tension free closure of the posterior sheath. The retromuscular space is accessed by incision and subsequent mobilization of the posterior sheath from the overlying rectus abdominis muscle. Below the arcuate line, the peritoneum and transversalis fascia are mobilized in a similar fashion. The degree of cranial-caudal dissection is based on the size of the defect as well as on the length of the midline incision. The dissection must create a space large enough to allow the reinforcement of the entire previous midline incision (not just the hernia defect) with a minimum of 5-8 cm overlap. This often mandates inferior dissection into the space of Retzius and superior dissection to the level of the central tendon of the diaphragm.

Figure 3a Hernia-defect

Figure 3b Incision of the posterior sheath

Figure 3c Mobilization of the posterior sheath

Figure 3d Arcuate line

Transversus abdominis release (TAR)

Top-down technique

Posterior sheath dissection is carried out laterally to the level of the linea semilunaris. The neurovascular bundles serving the rectus abdominis muscle are exposed and preserved (Fig 4). In the upper third of the abdomen the transversus abdominis (TA) inserts more medially on the posterior sheath. Medial to the semilunar line and neurovascular bundles, the posterior lamella of the internal oblique is incised thereby exposing the medial insertion of the TA muscle (Fig 5). After transecting the muscle fibers, the transversalis fascia is preserved and dissected off the TA laterally thereby creating a pocket. This pocket is developed in a caudal direction in order to mobilize the TA from the posterior elements (transversalis fascia and peritoneum) which will facilitate its subsequent division. The TA is then divided along the cephalo-caudal extent of posterior sheath mobilization (Fig 6 a-b). In the lower abdomen, the transversus muscle becomes aponeurotic and is divided, accordingly. Lateral and posterior mobilization of the posterior sheath is carried out to the level of the retroperitoneal fat and psoas muscle. Adequate dissection is achieved when the posterior sheath lays flat over the visceral content (Fig 7 a-b). Peritoneal defects are closed with absorbable suture.

Figure 4 Upper third of the abdomen

Figure 5 Exposure of transversus abdominis by division of the posterior leaflet of the internal oblique

Figure 6a Division of the transversus abdominis

Figure 6b Division of the transversus abdominis

Figure 7a Posterior sheath mobilization

Figure 7b Final posterior sheath mobilization

Bottom-up technique

The authors of the chapter believe that the division of the TA muscle is facilitated by executing the procedure in a caudal to cephalad direction that starts at the level of the myopectineal orifice below the arcuate line (Fig 8 a-d). This belief is supported by a number of factors including the prominence of preperitoneal fat in the lower abdomen facilitating posterior sheath mobilization, the observation that the peritoneum is often thicker in the lower abdomen reducing the risk of creating peritoneal rents, and division of the aponeurotic TA is technically easier than division of the TA muscle belly which inserts more medially in the upper abdomen. However, the approach may be determined by patient factors such as scarring from prior hernia repairs, and a combination of top down and bottom up approaches may be required. Therefore it is important to understand both approaches.

After posterior sheath mobilization, the space of Retzius is entered centrally, and the myopectineal orifice is exposed laterally.  Any concomitant inguino-femoral hernias are reduced. Below the arcuate line, the transversalis fascia is incised and the preperitoneal plane is entered, dissected, and a large pocket is created with lateral and cephalad dissection (Fig 9 a-c). This mobilizes the aponeurotic TA away from the preserved posterior elements, facilitating its subsequent division. As dissection progresses cephalad, the TA becomes muscular (Fig 10 a-b). Mobilization of the posterior sheath is deemed complete when it lies flat atop the viscera.

Initial deployment and fixation of mesh, placement of trocars on the contralateral abdomen, and re-docking

The cranio-caudal extent of dissection is measured as is the distance between the extent of flank dissection to the midline. These measurements are utilized to choose an appropriately sized mesh, which is deployed into the retromuscular and preperitoneal/pretransversalis space (Fig 11 a-b). The rolled mesh is then fixated with sutures or tacks along the postero-lateral abdominal wall. The “Suture trick” involves the placement of an absorbable suture in the top midline of the mesh, which  facilitates unrolling of the mesh after the posterior sheath is approximated and the linea alba is reconstituted.

The robot is undocked and under direct vision, mirror image trocars are placed on the contralateral abdomen (Fig 12 a-b). The trocars are placed above the posterior sheath and the scrolled mesh in the retromuscular position. The patient is rotated and the robot is re-docked. The Xi has the ability to rotate around a vertical axis, thereby, eliminating the requirement of rotating the patient.

Figure 8a Bottom s up

Figure 8b Myopectineal orifice and space of Retzius

Figure 8c Myopectineal orifice

Figure 8d Myopectineal orifice

Figure 9a Development of the preperitoneal pocket

Figure 9b Development of the preperitoneal pocket

Figure 9c Development of the preperitoneal pocket

Figure 10a Division of the muscular belly of the transversus abdominis

Figure 10b Division of the muscular belly of the transversus abdominis

Figure 11a Initial deployment of mesh

Figure 11b Initial deployment of mesh

Figure 12a Port position and double dock

Figure 12b Port position and double dock

Contralateral dissection

Contralateral and symmetrical TAR dissection is performed as described above. The initial trocars placed ultimately reside in the retromuscular space. Retroxiphoidal or retropubic dissection is performed as indicated to achieve sufficient overlap of the hernia defect as well as the overlying midline incision (Fig 13 a-b). Completion of adequate TAR dissection is confirmed when the two leaves of the posterior sheath rests flat against the abdominal viscera and can be approximated without undue tension.

Figure 13a Retroxiphoid dissection

Figure 13b Space of Retzius

Closure of the posterior sheath, final deployment of mesh, and restoration of the linea alba

Running suture is used to re-approximate the posterior sheath. Utilization of barbed suture may facilitate re-approximation (Fig 14 a-b). The authors prefer a Connel stitch to minimize contact between barbed suture and bowel. Any peritoneal defects are closed with absorbable suture, keeping in mind to avoid injury to the underlying viscera. The previously placed mesh is un-scrolled by the “suture trick” – pulling on the suture that was placed in the midline of the mesh. This can be done before or after restoration of the linea alba. Once flat, the mesh is secured to the abdominal wall using tacks or sutures (Fig 15 a-b).

The anterior fascia is re-approximated with barbed suture (Fig 16 a-b), which is facilitated by reducing the level of pneumoperitoneum to 6-8 mmHg. The dome of the defect is incorporated within anterior sheath closure to obliterate the dead space anteriorly. After the Linea alba is restored and the rectus is returned to the midline, retromuscular drains are placed under direct vision through one of the available ports.

Figure 14a Closure of the posterior sheath

Figure 14b Closure of the posterior sheath

Figure 15a Suture trick

Figure 15b Final mesh fixation

Figure 16a Closure of the anterior sheath

Figure 16b Closure of the anterior sheath

Postoperative care

Patients are immediately started on an early mobilization and diet pathway. All patients are provided with abdominal binders and drain care is taught as appropriate. Patients are discharged when they demonstrate per oral tolerance, are ambulating, and their pain is well controlled on oral medications. Patients are typically discharged on post-operative day one.

Concluding Remarks

The technical success of r-TAR is dependent upon preoperative optimization and adhering to well-established principles of both open and conventional laparoscopic repair. This includes but is not limited to careful adhesiolysis, primary closure of defects without undue tension, and sufficient overlap of reinforcing mesh. R-TAR as in the open counterpart, should be considered to be the ultimate definitive procedure for the treatment of large incisional hernias. This technique should not be overused and the anatomical planes of dissection must be respected. When performed appropriately, all the expected patient benefits of minimally invasive surgery should result.

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