Preoperative Considerations for Minimally Invasive Surgery

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Shawn Tsuda
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When a patient is deemed a candidate for a laparoscopic operation, the specific history relevant to this approach include the acuity and complexity of their disease process, a history of chronic obstructive pulmonary disease, cardiac disease, and prior abdominal surgeries. Pulmonary function testing and assessment of hypoxia baseline hypercarbia may be necessary, and may make laparoscopy more precarious than laparotomy in borderline cases. Cardiac risk factors are relevant to the patient’s anesthetic risk as well as the suspected insult of the planned procedure, but the reduction of cardiac output caused by pneumoperitoneum may need to be factored in. No amount of prior abdominal surgery contraindicates laparoscopy, but the location of scars and any history of adhesions encountered on prior surgeries are considered. Patient-specific variations in adhesion formation, inflammatory and infectious processes, foreign bodies such as mesh, and immunosuppession may all impact the degree of intra-abdominal scar formation. For example, colectomy required for perforated diverticulitis and frank peritonitis may indicate a more hostile abdomen then a patient who underwent an equivalent colectomy for benign disease.

Essential to the informed consent are a clear description of planned and possible port sites, risk of hernia, infection, bleeding, air embolus, pneumothorax, occult injury, and the need for open conversion. The available evidence for the benefits of laparoscopy should be outlined and an open procedure presented as an alternative. The surgeon should be prepared to answer questions regarding their experience with the surgery as well as the general volume of such cases performed at the facility.

Laparoscopy, in general, requires more space, equipment, and personnel compared to open surgery. When preparing for the operation, all of these must be carefully managed. Lack of adequate room space, failure of mechanical and electronic equipment, or discovery of inadequate number or expertise of personnel will increase the risk of operative delay, prolonged anesthesia, errors, complications, and open conversion rates.

Operating Room

The operating space has unique requirements in laparoscopy. Equipment and personnel, as well as the spacing of personnel, requires more real estate compared to open surgery. The room must accommodate at least two equipment towers on either boons or wheeled carts. The equipment towers include a video source, light source, insufflator, digital capture device, and optionally a printer, usually all on separate shelves to minimize overheating of components. There must be adequate space to move the boons or carts unobstructed from the head to the foot of the bed and with adequate clearance from the patient to avoid breaks in sterile technique. Two to three monitors are positioned either on boons, the equipment towers, or separate wheeled stands. Insufflator tubing and fiberoptic cables will run from the towers to the sterile field, effectively cutting off one route of movement between the patient and equipment. This barrier must also be considered and placed where either the circulating nurse or the scrubbed personnel do not need to past by to access necessary equipment or change positions. While most facilities house dedicated endosuites, many operating rooms are modular. When a procedure is planned, the surgeon should visit the theater and ultimately make a team-based assessment of adequate floor space for the planned procedure.

Equipment

When assessing equipment need and readiness for laparoscopic operations, a systematic preoperative approach is required. The technical complexity, increased risk of mechanical and electronic failure, and general increase of disposable equipment compared to open surgery makes this a science onto itself. Assessing the equipment from furthest to the patient and from top to bottom serves as a reliable methodology. Most equipment towers are topped by the video source. Its function should be confirmed as well as presence of a clear picture on all monitors. The light source is turned on and the expended hours checked on the bulb, which will be displayed on the device. Most modern light sources use a Xenon bulb, which carry an average of 300 usable hours. The insufflator is tested and two gas tanks confirmed full in the room. Any digital capture devices and printers should also be checked for correct operation. Energy device sources should also be turned on and undergo their functional tests. Any reposable trays and disposable staplers and graspers are confirmed, as well as type and number of ports required with adequate back-ups. The preoperative equipment check should occur prior to the patient being brought into the room. While its appropriate for the operating room staff to be trained in performing these checks, the surgeon should cross-check all of the equipment verbally with the staff prior to the patient being placed under anesthetic.

Patient Preparation

The decision to place a naso- or oro-gastric tube and foley catheter depends on the planned procedure. Procedures exceeding 1 hour will normally require both. Any surgery above the umbilicus or requiring a trocar in the upper abdomen should be preceded by gastric decompression. Similarly, low pelvic operations require bladder decompression for safety. This is particularly true for laparoscopic inguinal hernia repair or low ventral hernia repairs.

With the limitations of laparoscopy regarding reduced ability to retract and reduced visualization, gravity becomes an important tool for improving access to the quadrant of interest. For foregut, biliary, and diaphragmatic procedures, the reverse trendelenburg position is essential. At times, the operating table may be tilted to maximum, approaching 70 degrees. A footboard, bed straps, and a bean bag will help keep the patient from sliding off the bed. Arms and legs should be padded and either taped, wrapped, or bucked in place. The arm boards may be out in these cases, as the surgeons and assistants will be facing the patients head, from either side or between split legs.

For adrenal, kidney, or splenic surgery, a lateral decubitus position is best – with the exception of cases involving splenomegaly greater than 20 cm, as the weight of the spleen can make it unmanageable to control with laparoscopic instruments. The patient is positioned on their left or right side opposite the pathology. The arms are placed on an armboard and an airplane rest or on a pillow. A bean bag is essential. The patient is placed with the iliac crest over the break in the bed and a kidney bump may help. The leg laying on the bottom is bent at the knee at 60 degrees and the upper leg placed over pads or pillows at a slight flex. Body straps are used. This positioning requires multiple personnel, vigilance over the airway and accounting for all pressure points to avoid ulcers or nerve injury.

For surgery in the mid and lower abdomen, the arms should be tucked to the patient’s side, and secured as described above in anticipation of a steep Trendelenburg positioning. Failure to secure the arms can place the surgeon at an awkward position to access the pelvis or require an assistant to reach across the patient to drive the camera, which will be counterintuitive and suboptimal for comfort. For unilateral operations such as appendectomy, just the contralateral arm can be tucked at the patients side, allowing at least two personnel to comfortably position themselves across from the quadrant of interest.

Personnel

Besides the most Spartan environments that may include but one surgeon, one surgical technologist, and one circulating nurse, even the most basic laparoscopic operations are best served by at least a third scrubbed assistant, resident, or surgeon to accommodate the camera driving and possible assistant instrument. Fixed or robotic-controlled camera and instrument holders are commercially available but expensive and used on a widespread basis. On the opposite spectrum, academic teaching centers may have residents, students, and additional observers present as the video-based nature of laparoscopy make them ideal for observing cases akin to the operating auditoriums of old. The anticipated personnel should be considered into the floor space and positioning of equipment in the room.

The rule for positioning of personnel follows that the surgeon should be on the side opposite the intended surgical quadrant, or between the legs if a split leg technique is used for foregut surgery. The camera driver is usually on the same side as the surgeon, as the camera angle optimally follows the surgeon’s instruments. The assistant will be on the patient’s contralateral side. A surgical technologist’s position and equipment table is sometimes dictated by the limitations of floor space, but is often best when placed across from the surgeon, or on the same side if the surgical technologist also functions as camera driver. All other observing personnel are positioned so as not to impair passing of instruments, block view of the monitors, or jeopardize the sterile field. If these criteria cannot be met, they should not be a part of the sterile team and positioned well-away from the operative field. Figure 1 demonstrates operating room configurations for upper, lower, and retroperitoneal or splenic laparoscopic procedures.

Port Placement

Laparoscopic port placement should follow a defined methodology based on tried principles. The primary principle is triangulation. This dictates that the distance between two working ports and the target tissue have adequate distance between them, at least 15 cm. This allows for an angle between two instruments to be at least 30 degrees in relation to the perpendicular axis between the target tissue and the surgeon’s center for adequate counter-traction, retraction, or complex maneuvers like intracorporeal suturing. Other pertinent principles are the avoidance of existing scars and suspected abdominal wall adhesions for initial trocar access, and avoidance of structures susceptible to injury such as the bladder for supra-pubic ports, and the pleural cavity for superiorly-placed ports.

The port anticipated for camera placement can be placed in the midline, such as the umbilicus, to facilitate the widest range of view, or on the side of the working instruments to minimize collision. When possible, it should be placed lateral to the surgeon’s working ports, but occasionally and according to surgeon preference, the camera can be placed between two working ports – which provides the best angle of view and the maximum triangulation of instruments, but at the expense of crowding of the surgeon and the camera driver, whose arm must then past beneath that of the surgeon’s. The assistant ports can be one or two, and are on the side of the assistant, not passing the midline. This may require the assistant to assist with a reversed camera view in some cases. Figure 2 demonstrates a variety of port configurations.

The type and size of ports are dictated by availability and surgeon’s preference. Almost any kind of instrument except for surgical staplers and tissue removal bags have 5-mm port counterparts. Microports for 2 or 3 mm instruments are also available. Non-disposable trocars may save on cost. Bladed trocars are less common, as they cause an incised defect in the abdominal fascia, while blunt-tipped trocars or trocars that follow a needle-deployed sheath may reduced the risk of hernia by using a fascia and muscle-splitting mechanism.

Initial Trocar Placement

The choice for initial trocar placement is governed by surgeon preference, the patient’s specific surgical history, body habitus, and the planned abdominal quadrant(s) of surgery. The choices are, in order of least risk for major bowel or vascular injury, open-cutdown, insufflating needle followed by optical trocar placement, needle insufflation with blind trocar placement, optical trocar placement without prior needle insufflation, and blind trocar placement (Table 2). An open cut-down approach is classically performed at the umbilicus, but can be duplicated anywhere on the abdominal wall. An incision is made in the skin, and the anterior fascia identified. A Kocher clamp, or number-0 sutures can be used to elevate the fascia as a vertical incision is made in the midline. Each layer is visualized, and if the peritoneum found to be intact, it can secondarily be grasped by clamps to raise it off the underlying viscera while it is incised carefully with dissecting scissors. Once there is visual confirmation of the intra-abdominal cavity indicated by visible omentum or intestines, a 10 to 15 mm trocar is placed in the defect and secured by the stay sutures on the anterior fascia or directly to the skin. Some surgeons may choose to digitally explore the cut-down incision and assure there are no adhesions around the circumferential underside of the abdominal wall. This maneuver may be unnecessary in the virgin abdomen if there is visual confirmation of entry.

An equally common technique for first entry into the abdomen is needle insufflation. The insufflating needle is a spring-retracting 14 to 18 gauge needle. The technique for placement involves making a 5 mm skin incision and passing the needle through the layers of the abdominal wall. The Scarpa’s fascia, anterior fascia, and peritoneum will confer three tactile ‘pops’ which is followed by aspiration with a prefilled syringe to exclude blood, bile, or other bowel contents. A brisk injection of 1 cc of saline followed by removal of the syringe to confirm the fall of the visible fluid column is called the drop test. Occasionally, subtle relaxation on the needle to separate it from underlying bowel or omentum is required to realize the drop of the fluid column. Connecting the insufflation tubing will reveal an immediate pressure that must be between 0 and 10 mmHg to assure the needle tip is not incorrectly placed within the abdominal wall or in the pre-peritoneal space. The flow of carbon dioxide will be limited by the diameter of the needle to 2-3 liters per minute. A higher rate of major vascular structures, particularly the iliac vein or artery, has made other locations for the insufflating needle more commonplace. Palmer’s point, which is along the left subcostal margin, just lateral to the midclavicular line to avoid the superior epigastric vessels, may provide a safer buffer for needle entry. The rib cage serves as a natural tenting structure and there is usually protective omentum overlying the stomach and colon. Gastric decompression is mandatory. A careful history and examination should exclude splenomegaly, hepatomegaly, or nearby masses before choosing this site. While any other location on the abdomen can be considered a potential site for insufflating needle insertion, especially when prior surgical scars are present, the umbilicus or Palmer’s point should be the primary candidates. The right upper quadrant is not idea as the gallbladder and larger right lobe of the liver can be particularly prone to injury, or a history of cholecystectomy will make potential adhesions a relative contraindication in that quadrant.

In the virgin abdomen and absence of known bowel obstruction or other precarious pathology such as a known large mass or organomegaly, blind trocar insertion can be performed once insufflation is achieved to the desired pressure, usually 15 mm Hg. However, most commercial 10, and some 5, mm trocars have ports for a camera where direct visualization of the abdomen is possible during entry. With the camera focused on a near aperture, the subcutaneous tissue, muscle, and peritoneum can be easily identified and a controlled entry into the now insufflated space safely achieved. Although theoretically less safe, using the optical trocar without pre-insufflation, or placing trocars blindly without insufflation are also feasible techniques.