The TEP repair for Inguinal Hernia

The TEP repair for Inguinal Hernia
S J Nixon

Some Basic Facts and Myths exposed

Dissection proceeds from the mid line laterally towards the anterior superior iliac spine, keeping in the roof of the exposed pre-peritoneal space avoiding injury to the iliac vessels. In thin patients it may be possible to see the femoral canal and adjacent iliac vein and artery although these structures are avoided rather than exposed. The three hernial defects are shown as the deep inguinal ring in blue, a direct defect in yellow and the the site of a femoral hernia in green.

One 10 mm metal port with a conical shoulder and long, blunt introducer (eg Aesculap EJ441R)

Two 5 mm metal ports preferably with an outer spiral thread to aid fixation (eg Aesculap EJ701R)

Precise entry into the preperitoneal space is paramount at the outset. Accidental entry into the peritoneal cavity, provocation of significant bleeding and displacement of the inferior epigastric vessels from the abdominal wall lead to significant increase in the technical difficulty of the operation. The (right handed) surgeon stands on the patient's left side. A 2-3 cms horizontal incision is made just below the umbilicus and deepened by blunt dissection to expose the linea alba between Langenbeck retractors. This is picked up between 2 forceps and a midline, vertical incision, one centimetre in length is made through it to enter the pre-peritoneal space. A curved, large artery forceps is passed, curve upwards, beneath the linea alba and towards the pubic bone, to begin to develop the space. Care is taken not to enter the peritoneal cavity by keeping in a plane just deep to the linea alba. If the peritoneum is entered this is usually obvious to the surgeon as the forcep passes down in the pelvic cavity. If this occurs then remove the forcep and reinsert it carefully keeping in a more superficial plane. When placed in the correct space, downwards pressure on the forceps results in depression of the overlying skin. The blunt introducer with the 10mm port is then placed into the space and passed inferiorly until the pubic bone is felt in the mid line. The left hand of the operator is place on the pubic bone to help guide the trochar. Again care should be taken not to pass the trochar too deeply risking injury to the bladder and peritoneum.
(video of approach) WM56modem WMBroadband

Limited blunt dissection is performed in the mid line with this trochar to develop the space further. The port is advanced on the trochar which is then removed.

The port is sutured to the skin using a vycryl J suture to help reduce gas leakage and prevent accidental removal. Insufflation is started using a pressure of 10 millimetres of mercury. Higher pressure is avoided at it can lead to surgical emphysema.

A 10mm, straight telescope is introduced through the port and the pubic bone should be visible is most cases. The pre peritoneal space is further enlarged with the telescope, now under vision. A 5mm port is then placed in the midline, 3 finger-breadths above the pubic bone. If placed too low, this port will impede positioning of the mesh later in the operation. A second 5 mm. port is placed in the midline midway between the other two ports. Accurate positioning of these ports is helped by using the telescope or 10mm port as a guide. They cannot be placed under direct vision as the preperitoneal space is compressed as the ports are inserted. An inexperienced surgeon may be helped by prior insertion of a standard green needle under vision to judge the correct angle and depth.

Now under vision, 2 blunt atraumatic graspers are passed through the 5 mm ports. If the surgeon loses direction then these instruments should be reinserted in the midline towards the pubic bone and not laterally where they might cause bleeding. The surgeon and camera assistant move to the side opposite the hernia to be dissected.

The midline space is further developed by blunt dissection. The curve of the pubic arch is cleared of flimsy attachments well across the midline as the mesh should be positioned so .that it just crosses the midline

. The pubic bone acts as the horizon for surgeon and camera man. All subsequent dissection should take place above the level of this bone remembering that the direct hernial defects and the deep inguinal ring lie above this level whilst the iliac vessels lie inferiorly. By blunt dissection, working in the roof of the space, the surgeon progresses laterally, pulling the preperitoneal structures down from their loose attachments to the anterior abdominal wall. The basic technique is to use the lower of the two dissecting instruments to elevate the abdominal wall in the roof of the dissection whilst using the upper of the dissectors to pull the preperitoneal tissues downwards. The actions of the left and right hands of the surgeon are reversed for right and left sided herniae. A valuable technique is to place the two dissectors with their ends touching and then spread them outwards firstly along the plane being dissected and then at right angles to this plane.

The next anatomical structure identified may be a direct hernia if present. The surgeon often sees a white, sac like structure perplexingly coming towards the camera, out of the muscles, with adherent fatty tissue. We call this the "reverse sac" of a direct hernia. It is in fact the posterior aspect of the transversalis fascia which can look surprisingly like the peritoneum. As the fatty tissue is separated and pulled back into the abdomen, the gas pressure blows the direct hernial defect outwards, clearly demonstrating the weakness. In a

direct hernia, its content is usually composed of fatty tissue and the peritoneum is not seen. The entire content of the hernia is reduced fully exposing the muscle defect. (video of direct hernia repair)WM56modem WMBroadband

Dissection proceeds more laterally to expose the inferior epigastric artery and vein. Care needs to be taken not to pull these structures downwards from the abdominal wall. To avoid this, as soon as they are identified, the lower dissector is placed under the vessels, gently elevating them whilst adherent tissues are dissected downwards. Continuing more laterally, the spermatic cord structures, and indirect hernial sac if present, come into view. The spermatic cord can be grasped with the atraumatic forceps and elevated to separate it from flimsy attachments. Its structures can be teased apart to exclude the presence of an indirect sac. If no sac is found, dissection continues laterally towards the anterior superior iliac spine. This creates a space for the mesh to lie in. It is often possible to see the peritoneal reflection as a white line which can be grasped and dissected away from the deep inguinal ring again to allow the mesh to lie unimpeded.

In the case of an indirect inguinal hernia, the sac of the hernia lies above and in front of the spermatic cord which is initially hidden from view. The sac is grasped using the lower dissector and pulled towards the mid line, opening a space lateral to the sac but keeping as close as possible to the wall of the sac. In most cases, dissecting behind the sac will expose the spermatic cord structures at the lowest point of dissection. The sac is now retracted laterally and cleared of adherent structures medially until the vas and other cord structures are identified at its lower margin. A window is developed between the hernial sac above and the cord structures below as shown on the left.. The sac is then pulled out from the deep

inguinal ring, progressively separating it from the cord and adhesions to the deep inguinal ring. Once the end of the sac is reached it can usually be pulled apart from its final attachments and delivered back into the abdomen. The fully reduced sac is shown on the right.. In most cases, blunt dissection only is required. When an extremely long and large indirect sac is found, after some dissection to deliver part of the sac from the deep inguinal ring, it is occasionally necessary to divide the sac using diathermy scissors. There is no need to close either end of the divided sac. Accidental opening of the peritoneum is relatively common and, whilst it does result in contraction of the preperitoneal space, loss of vision and increased technical difficulty, I make no attempt to close the peritoneum and conversion to open surgery should not be required. Very occasionally, if pneumoperitoneum causes complete loss of vision, I stop insufflation, place a Verres needle in the abdomen to release the abdominal pressure and then restart insufflation, leaving the Verres needle in position. (video of indirect repair)WM56modem WMBroadband

In the case of a bilateral hernia, the surgeon and camera operator now move to the opposite side and repeat the steps above

Once dissection is complete the telescope is removed and a 15x10 centimetre, polypropylene patch inserted through the 10 millimetre port. I hold what I intend to be the medial lower corner and avoid wrapping the patch in any way as this only needs to be unwrapped once inside the patient. Part of the mesh will still be in the 10mm port and needs to pushed down using the telescope then grasped with the upper dissector and placed as far down as possible away from the telescope and two dissectors. My normal plan is to identify the lower medial corner and place this behind the pubic bone slightly across the midline. I then identify the medial upper corner and straighten the short, medial edge of the mesh. I then progress laterally by identification of the upper and lower edges, spreading the mesh against the abdominal wall but taking care not to pull the mesh towards the camera, nor to push the mesh too far down into the retropubic space, nor too far laterally so that the medial border no longer crosses to the contralateral side. In effect, due to variable folding of the mesh on insertion, this part of the operation is one of most difficult technical aspects to master but becomes easier with experience.

With the mesh in ideal position, it should cover all three potential hernial defects ; direct, indirect and femoral. No fixation is necessary. In the case of bilateral herniae, I simply insert two 15x10 meshes. On average, bilateral repair takes 6 minutes longer than unilateral surgery.

20mls of 0.5% bupivacaine is placed in the preperitoneal space using a quill inserted via the lower 5 mm port. Insufflation is discontinued and the gas allowed to escape under vision. I prefer to hold the lower edge of the mesh in position during desufflation to prevent it being rolled upwards.

The three ports are removed. The sub-umbilical incision is closed with the remainder of the Number 1 Vycryl suture on a J needle used to secure the 10mm port. 10 mls of 0.5% bupivacaine are injected into the three small incisions and the skin closed with steristrips.