General information regarding LAP-Band™ (LASGB)
LAP-Band System technical data
The stomach band (Kuzmak band) was initially implanted using open techniques and later on modified for laparoscopic use (Laparoscopic Adjustable Silicon Gastric Banding, LASGB). The band is made of a silicon elastomer, a material known for its good tissue compatibility. It does not contain any latex or natural rubber materials. It measures 13mm in width, and the inner diameter of a closed band is 9.75 or 10cm in a slightly larger version. The inner membrane of the band can be filled to a maximum of 5ml when the inner diameter is constricted. Recently a new wider band (11cm) was made available, which can be filled to a maximum of 8ml. The band is connected to the injection reservoir (reservoir, port) using a 50cm-long hose (catheter) via a stainless-steel adapter piece. The band, catheter, and port are x-ray positive. The port is manufactured from titanium and is compatible with visualisation procedures like MRT (magnetic resonance tomography). The chamber system utilises a high-pressure membrane (plastic-septum), which can be punctured with a specially designed 20-gauge needle up to a thousand times even under high pressure, without becoming damaged.
Positioning
The patient is placed on an operating table suitable for his/her weight on his/her back with legs spread. Active participation by the patient may be advantageous for weight reasons, so anaesthesia should be delayed. To allow the fat-tissue to shift downwards thus allowing a better view into the upper abdomen, the patient is positioned in a semi-upright position during the operation (anti-Trendelenburg position). The operating table (load capacity greater than 200kg) and personnel may have technical difficulties preventing the patient from shifting or slipping.
Equipment
In most cases, specially designed long laparoscopic instruments (trocars, other instruments) will not be required, but they should be available. A wide variety of laparoscopic instruments and technical equipment as found in visceral-surgical centres concentrating on laparoscopic surgery are required for the operation. Otherwise, only a few additional special instruments like an articulate dissector, used to pull the band retro-gastrically, are necessary.
Positions for the surgical team
The operating surgeon stands between the patients legs, while the first assistant is on the right functioning as camera operator, and the second assistant, whose primary task is to hold the liver, is on the left. The scrub nurse stands to the left of the operating surgeon thus enabling the nurse to hand instruments to the surgeon’s right hand in an ergonomically efficient fashion. The monitor is positioned to the left thus providing a clear view to the operating surgeon and camera operator. Experience has shown that this positioning is only of slight disadvantage to the 2nd assistant, who will have to observe the operation either over his/her left shoulder, or on an additional monitor installed to the right of the patient.
Fig. 8: Positioning of the surgical team
O = Operating surgeon
1 = Camera operator, (1st Assistant)
2 = 2nd Assistant
S = Scrub nurse
A = Anaesthetist
M = Monitor to the left of patient, possibly second monitor to patient’s right.
Laparoscopic entry points
Entry points must be positioned far enough up the upper abdomen, depending on the degree of morbid adiposity and body type, to keep the distance to operational areas as short as possible and to avoid material strain on the lever-action of the instruments. The positions marked on the abdominal wall will shift downwards by several centimetres once the pneumoperitoneum is in place depending on the size of the abdominal cavity. Fig. 9 shows our entry points.
Fig. 9: trocar positions:
A: 12mm (working cannula)
B: 5-10mm: Liver retractor
D: 12mm (working cannula)
C: 10mm (optical entry point)
E: 5-12mm (working cannula, facultative)