Key concept : Understand the utility as well as the limitations of BMI as it pertains to various categories of patients .

While Chap. 2 of this textbook provides a more compre- hensive risk assessment for all patients, it is worth highlight­ing a few things as it pertains to the obese population. As with any patient, initial work-up includes a general history and physical examination. Your goals should be to both identify how to manage the disease you are presented with and also implement an appropriate time line. A perforated obstructing cancer requires immediate intervention, but identifying that the patient has pulmonary issues, underlying cardiac disease, or adrenal insuffi ciency may alter the way you manage them perioperatively. For elective operations, a standardized approach through a preoperative evaluation clinic is a mean­ingful method of assessing all high-risk surgical candidates. Obese, and particularly morbidly obese, patients should always be considered higher risk and evaluated through a standardized setting when possible [ 6 ]. Preoperative educa- tion and counseling helps to defi ne goals of postoperative outcomes and expectations to minimize complications. In this arena you can discuss several things that may arise that are more common in obese patients. For example, it is imper­ative to inform the obese patient that they have a higher likeli­hood of needing to open the wound for a wound infection and will need to pack the wound postoperatively. For those with pulmonary issues, you should discuss the increased chance of needing to stay intubated for longer cases or the need for pro­longed DVT chemoprophylaxis—even after discharge. It is also an opportunity to ensure that you have special wheel­chairs, beds, and trapeze available to help your get out of bed, ambulate, and move around the hospital.

Pulmonary : Preoperative pulmonary evaluation should include an assessment of undiagnosed obstructive sleep apnea, for which the risk factor most closely associated is

weight, and adhesions. Unfortunately, the instrumentation that we use often adds to the complexity. The long thin min­iature shaft and narrow end effectors used for grasping and dissection prove mechanically disadvantaged when attempt­ing to manipulate the increased volume and weight of organs involved. Lastly, the use of gravity as the additional retractor in laparoscopic surgery poses signifi cant issues in the morbidly obese. In order to adequately expose the oper­ative fi eld, extremes of body positioning with steep Trendelenburg and “reverse T” along with lateral tilt are needed. In reality, some of these are nearly impossible with the extremes of weight and poses hazards to peripheral nerves and even dislodgement of the patient (Fig. 26.1 ). Not surprisingly, the initial reports of laparoscopic colectomy often cited severe obesity as a relative contraindication to this technique.

As in any other operation, preparation for a laparoscopic colectomy in the obese patient remains paramount. First, you must mentally prepare and comprehend that these cases possess unique challenges that increase in complexity as BMI increases. Also, you must be realistic by consider­ing your own laparoscopic experience and where you are on the learning curve. Identifying a complex operation involves consideration of patient characteristics such as obesity, severity of pathologic condition, urgency, prior abdominal operations, and type of colectomy planned. Conversion serves as a surrogate marker for the degree of technical diffi culty of a procedure but also may be a marker for good judgment on your part. In a study of nearly 1,000 laparoscopic colectomies, the authors identifi ed surgeon experience, left-sided resection, fi stula and abscess, and obesity as risk factors for conversion. Furthermore, there is an exponentially greater risk of conversion (vs. simply cumulative) when multiple factors are present. For exam­ple, an obese patient requiring sigmoidectomy for divertic­ulitis complicated by colovesical fi stula will be a daunting task for any surgeon but especially for the surgeon with limited laparoscopic experience. This is not to say that you should not attempt a diagnostic laparoscopy, proceed with initial dissection, and perform the operation laparoscopi­cally to the extent you feel safe and comfortable. This is often a great objective, at any point along your learning curve. One effective strategy is to set a time limit and deter­mine ahead of time that if you are not making progress by the end that you will convert. Another operative approach in the patient described above or other complicated left­sided resections is to focus on the splenic fl exure and colon mobilization. After that is performed, the fi stula and resec­tion can be approached through a low midline or Pfannenstiel incision under direct vision. Remember, a splenic fl exure takedown in a morbidly obese patient with a heavy, thick body wall that has to be retracted in the open setting is not easy either.