Patient preparation and positioning for laparoscopic and robotic urologic surgery

Introduction

Appropriate patient selection, thorough preparation, and careful patient positioning are essential in achieving a safe and successful outcome in laparoscopic surgery. Regardless of a particular surgeon’s technical expertise, inadequate execution of these important surgical preludes can result in unnecessary complications, extend operative time, and challenge the course of recovery. Moreover, during surgery, the surgeon must continuously evaluate for adequate forward progress to warrant continuing the case laparoscopically versus converting to open surgery. A surgeon will never be faulted for converting to open surgery for failure to progress laparoscopically. However, fault can be found for those surgeons pushing forward when there has been no technical progress in a case or in a case where they have little experience, resulting in unnecessary complications or extended operative times beyond what would be considered acceptable. Recognizing these situations during patient selection and proceeding with these cases with a healthy dose of surgical humility are fundamental in avoiding major complications and achieving a successful outcome.

Patient selection

Preparation for laparoscopic surgery begins first and foremost with appropriate patient selection. It is worth mentioning that the most experienced laparoscopic surgeons in the world are also experts at patient selection. Each case must be carefully considered prior to reaching the operating room. Relative contraindications to laparoscopy should be considered. The most significant of these result from the altered physiology of pneumoperitoneum, the potential for prolonged procedure time during a team’s early learning curve, and the dangers of minimally invasive abdominal access. As urologists have become more proficient in laparoscopy, traditional absolute contraindications have evolved to become relative contraindications; yet, these factors need to be considered, and the decision to proceed with laparoscopy should be based on surgeon skill, experience, and comfort.

Pneumoperitoneum of laparoscopy can significantly alter cardiopulmonary physiology. Therefore an experienced anesthesia team is vitally important. Several medical conditions are worthy of special mention and should prompt a careful review by both the surgical and anesthesia teams. These include but are not limited to chronic obstructive pulmonary disease (COPD), restrictive lung disease, active cardiac disease, obesity, glaucoma, and cerebrovascular disease. Carbon dioxide (CO ₂ ) is the gas of choice for pneumoperitoneum because it is readily available, cost-effective, resistant to combustion, and easily absorbed by tissues, and it has a high diffusion coefficient and is quickly released via respiration. However, patients with pulmonary compromise present unique challenges during particularly long surgical cases. Insufflation of the peritoneum with CO ₂ can exacerbate hypercarbia in a patient with COPD with a severe ventilation-perfusion mismatch. Hypercapnia (arterial CO ₂ > 60 mm Hg) is cardio-depressive and can lead to acidosis and cardiac arrhythmias if left untreated. The typical approach for hypercarbia is for the anesthesia team to increase the ventilation rate and/or tidal volume and for the surgical team to reduce intraabdominal pressure (from 15 mm Hg down to 8–12 mm Hg). During surgery, the anesthesia team can easily monitor end-tidal CO ₂ , which is proportional to arterial CO ₂ . It should be noted, however, that in patients with impaired pulmonary gas exchange (e.g., obstructive lung disease, low cardiac output, or pulmonary embolism), arterial CO ₂ can be significantly greater than end-tidal CO ₂ . For these patients, measurement of arterial blood gas is recommended during prolonged cases for more accurate monitoring of arterial CO ₂ . After laparoscopic surgery, patients with pulmonary compromise should be closely monitored for signs of hypercapnia.

Patients with cardiac disease are also at unique risk during laparoscopy. In particular, patients with cardiomyopathy, congestive heart failure, and ischemic heart disease require close monitoring as a result of the altered physiology of pneumoperitoneum. Increased intraabdominal pressure due to insufflation is exerted directly on the vasculature, decreasing venous return and preload, as well as systemic vascular resistance and afterload. These conditions can be further exacerbated by decreased myocardial contractility induced by hypercapnia, ultimately leading to decreased stroke volume and cardiac output. Accordingly, careful fluid resuscitation by the anesthesiologist and attentive control of bleeding by the surgeon are warranted to prevent hypovolemia in these patients.

Pregnancy was previously considered a contraindication to laparoscopy due to concern for placental ischemia in response to pneumoperitoneum; however, pneumoperitoneum has been shown to be safe in pregnant women at standard pneumoperitoneum. It is recommended to proceed with the lowest acceptable pressure of pneumoperitoneum that the case allows. Additionally, during the third trimester, initial intraperitoneal access via Veress needle has been shown to have a higher rate of uterine insufflation due to the elevated fundus; thus, it is prudent to obtain access via an open (Hasson) approach in these patients. Despite the proposed safety of laparoscopy during pregnancy, the indications must be weighed carefully with the risks of the procedure, as the majority of urologic laparoscopic procedures can be delayed until postpartum.

Obesity is no longer considered a contraindication for laparoscopic surgery. In fact, with robotic assistance, some laparoscopic cases such as radical prostatectomy or uncomplicated partial nephrectomy may be technically easier than open or pure laparoscopy due to improved visualization and wrist articulation. However, prolonged positioning for complex laparoscopy combined with obesity in a patient may increase the risk of pressure injury, neuropraxia, or even rhabdomyolysis. If positioning is steep Trendelenburg (ST), increased intraocular pressure can lead to ischemic optic neuropathy and postoperative vision loss in patients with glaucoma. Patients with cerebrovascular disease should be carefully selected as ST positioning can contribute to increased intracranial pressure. The astute urologist should not hesitate to seek specialty evaluation for any of these comorbidities prior to proceeding with surgery.

Patients with previous history of abdominal surgery or peritonitis should be carefully considered for laparoscopy. These conditions can result in the formation of a significant number of adhesions involving intraabdominal viscera, presenting unique challenges and dangerous pitfalls for trocar placement. Veress needle placement for insufflation can be used away from the known surgical scars if the surgeon has experience with this technique. If not, then an open Hasson technique should be used for initial access. Regardless of insufflation method, no ports should ever be placed without direct visualization or blindly, including the initial abdominal access port. There are several varieties of visual obturator trocars available, which provide safer options for abdominal access by allowing a camera to be placed into the obturator, displaying the abdominal layers during access to an insufflated abdomen. Moreover, subsequent trocars should always be placed under direct vision after adhesions are cleared from the abdominal wall. Retroperitoneal or preperitoneal access can be considered in patients with a history of multiple complicated surgeries. Experience and additional training with these techniques is recommended. In the authors’ experience, retroperitoneal access is exceedingly challenging in patients with a BMI > 35 and should be undertaken cautiously.

Patient preparation

Prior to surgery, all patients should be evaluated by an anesthesia team, and appropriate specialty clearance should be obtained. Preoperative testing, including electrocardiogram (ECG), laboratory tests, and urinalysis and cultures, should be performed if appropriate. Patients should be appropriately counseled on the risks and benefits of the surgery; informed consent should be obtained prior to the day of surgery to limit anxiety. For patients on anticoagulants, the decision to stop anticoagulation is often a multidisciplinary decision between surgery, anesthesia, and cardiology. Surgical teams should not hesitate to communicate regarding this issue. In general, antiplatelet therapy such as aspirin may slightly increase the risks of perioperative bleeding events; however, in high-risk cardiac patients, most surgeons will choose to continue low-dose aspirin without clinically significant bleeding risk. Patients who have recently experienced acute coronary syndrome or recent cardiac stent are often on dual antiplatelet therapy for 6-12 months. If possible, one should consider delaying surgery until after this period. Instructions for stopping anticoagulation agents and antiplatelet agents should be clearly conveyed to the patient. If an ostomy is planned, the patient should be evaluated by an ostomy nursing team, and potential ostomy sites should be marked bilaterally for placement. Preoperative ostomy education can be reviewed, and supplies such as ostomy pouches, thromboembolism-deterrent (TED) hose, and chlorhexidine body scrubs can be provided at this time.

Prevention of surgical site infections begins preoperatively and includes skin treatment, mechanical bowel preparation when necessary, and antibiotic prophylaxis. On the evening prior to surgery, the patient should be instructed to shower with a chlorhexidine body scrub and to refrain from waxing, shaving, or trimming the surgical site to prevent microtrauma to the skin. For the same reason, body hair should not be shaved with a blade, but rather trimmed with mechanical clippers, which have been demonstrated to decrease the risk of surgical site infection. After the patient has been positioned, abdominal surgical sites should be sterilized with chlorhexidine, and genitalia with povidone-iodine solution.

If the bowel will be manipulated, mechanical bowel preparation with polyethylene glycol or sodium phosphate can be administered the evening prior to surgery. The constipated patient can be administered enemas or manually disimpacted. The rationale for mechanical bowel preparation includes reduction of fecal flora, easier manipulation of bowel, improved visualization, and easier anastomotic stapling. However, meta-analyses of colorectal surgery have not identified a clear statistical benefit to mechanical bowel preparation. Cochrane reviews were able to demonstrate trends towards decreased rates of anastomotic leakage with mechanical bowel prep, though they did not reach statistical significance. Maneuvers for aggressive bowel preparation were further detracted by potentially morbid colonic mucosal changes, fluid shifts, and electrolyte derangements. Similar controversy exists surrounding the administration of oral antibiotic bowel preparation or selective decontamination of the digestive tract with regimens such as tobramycin, polymyxin E, and amphotericin-B. In general, parenteral antibiotic prophylaxis is used in lieu of these agents. At our institution, for pelvic surgery (eg., cystectomy, prostatectomy) we ask patients to follow a clear liquid diet the day before surgery and perform a sodium phosphate enema the evening before surgery. No other oral antibiotics or oral mechanical agents are used.

There is less controversy regarding parenteral antibiotic prophylaxis prior to incision. For laparoscopic procedures without entry into the digestive or urinary tract, American Urological Association guidelines recommend perioperative administration of a first-generation cephalosporin or clindamycin as an alternative in patients allergic to penicillin. If the urinary tract will be entered, a first-generation cephalosporin or sulfamethoxazole-trimethoprim is recommended. Ampicillin/sulbactam or an aminoglycoside (eg., aztreonam) with metronidazole or clindamycin can be used as an alternative regimen. For cases involving the small bowel, first-generation cephalosporin is recommended. Alternative regimens include clindamycin/aminoglycoside and second-generation cephalosporin. For cases involving the large bowel, preferred regimens are first- or second-generation cephalosporin with metronidazole or ertapenem alone. Alternative antimicrobial prophylaxis includes ampicillin/sulbactam, ticarcillin/clavulanate, and piperacillin/tazobactam. Preoperative antimicrobial prophylaxis may be altered based on your institution’s antibiogram. At our institution, first-generation cephalosporin is used for the majority of cases; first-generation cephalosporin is combined with metronidazole for all cases involving the bowel. All antibiotics should be administered 30 to 60 minutes prior to incision and should be continued for no more than 24 hours if there is no gross contamination during the procedure.

Preoperative preparation should also include measures to prevent venous thromboembolism (VTE), a common cause of preventable death in surgical patients. The American College of Chest Physicians have developed evidence-based clinical guidelines for nonorthopedic surgical patients. Intermittent pneumatic compression (IPC) should be applied to all laparoscopy patients prior to induction of anesthesia. For patients at moderate and high risk for VTE without high risk of bleeding complications, subcutaneous heparin or low-molecular weight heparin (LMWH) should be administered. For high-risk cancer patients, extended-duration prophylaxis with LMWH, 40 mg subcutaneously once daily for 3–4 weeks, is recommended. Patients at high risk for bleeding complications can have pharmacologic prophylaxis withheld, though they should have mechanical prophylaxis with IPC preoperatively and should initiate pharmacologic prophylaxis when the risk of bleeding diminishes. Pharmacologic prophylaxis should be administered 2 hours preoperatively, though LMWH appears to be effective 12 hours preoperatively.

Alvimopan is peripherally acting μ-opioid antagonist that competitively binds to the μ-opioid receptor in the gastrointestinal tract. It is designed to reduce the gastrointestinal side effects, such as ileus from opiates. Alvimopan was approved by the FDA in 2008, and it has been shown to accelerate upper and lower gastrointestinal recovery following surgeries involving the gastrointestinal tract; in urology, it has been shown to reduce hospital stay and reduce overall cost after radical cystectomy and urinary diversion. It should be administered orally prior to receiving any opiates; ideally it is given in the preoperative area for patients undergoing bowel diversion at least 30 minutes prior to incision.

Patient positioning considerations

Prevention of positioning-related injuries should be of primary consideration when manipulating the anesthetized patient. Required pharmacologic paralysis for laparoscopic surgery compounds the risk of injury as a result of decreased muscular tone. These injuries can be broadly categorized into peripheral nerve injuries, vascular-mediated injuries, and skin injuries, all of which can result in significant morbidity and mortality to the patient. Recognition of risk factors for positioning-related injuries and diligent prevention are key to avoiding these complications.

Injuries to peripheral nerves are a result of stretching or compression at susceptible nerve segments, which can compromise neural blood supply, tear neural tissue, and disrupt axoplasmic flow. When positioning the patient, care should be taken to ensure adequate padding at the elbow to avoid ulnar nerve compression at the cubital tunnel. If the arms are not tucked at the side, abduction at the shoulder should be limited to less than 90 degrees to prevent stretching of the brachial plexus over the humeral head. In the ST position, shoulder bracing should be avoided to prevent further loading of the brachial plexus. While in the full flank position, an axillary roll should be placed one hand’s breadth inferior to the axilla to support these important structures. When positioning the patient’s lower extremities, close attention should be directed to the peroneal nerve, which can be compressed at the head of the fibula, and the median nerve, which can be injured at the medial tibial condyle.

Vascular-mediated injuries such as compartment syndrome and rhabdomyolysis are not unique to laparoscopic urology, but their risks may be exacerbated by insufflation, ST positioning, long operative times, and patient factors such as obesity. One possible contributing factor is ST position. With the legs elevated in the lithotomy position, perfusion pressure at the calf is reduced, which may increase the risk for compartment syndrome. Insufflation has also been theorized to contribute to decreased lower limb perfusion, while obesity may increase forces exerted on the gluteal and back muscles. Long operating times (> 4–5 hours) have also been associated with the development of rhabdomyolysis. Prevention of compartment syndrome and rhabdomyolysis should focus on limiting the degree of ST inversion and limiting operating time in morbidly obese patients.

The patient’s skin should be closely examined, and any preexisting lesions should be noted. Then all bony protuberances should be comfortably supported to distribute any forces that could lead to skin ischemia during a prolonged case. Similarly, any foreign bodies placed against the patient’s skin, such as pulse oximeter connectors and IV access ports, should also be padded. Gel pads, foam pads, egg crate foam, gauze, and towels can all serve in this capacity. To protect the patient from electrical burns, the electrocautery grounding pad should be well adhered across its entire surface to the patient’s skin. If necessary, body hair should be clipped to improve pad adherence. All patient jewelry should be removed, and the grounding pad should be placed as close to the operative field as possible to prevent alternate site burns.

Patient positioning—laparoscopic pelvic surgery

Patient positioning for laparoscopic pelvic surgery has traditionally been the lithotomy position in ST. While this allows the small bowel to fall away from the surgical site, affording increased working space and improving visualization, the position has numerous disadvantages. Chief among these are the risks to the patient as a result of the steep, inverted position, resulting in decreased perfusion pressure of the lower extremities and increased intracranial and intraocular pressures.

Keeping the patient safely secured to the operating table and preventing an intraoperative fall is also a major consideration. Many devices and materials have been developed specifically for this application. Examples include vacuum bean bag immobilizers, high friction gel or foam pads (The Pink Pad, Xodus Medical Inc, New Kensington, PA), and restraint systems such as the TrenGuard cervical bump (D.A. Surgical, Chagrin Falls, OH) ( Fig. 1.1 ). In addition to these restraint methods, taping is often needed for extra support. Prior to prepping and draping, a full tilt test should be performed, by placing the table in the maximum Trendelenburg position, to ensure the patient does not significantly shift or slide. Familiarity with the patient securement system of choice is absolutely necessary to prevent slipping or falling.