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The Modified Lithotomy: A Surgical Position for Lower Extremity Wound Care Procedures in Super Morbidly Obese Patients. A Case Study

Case Report

The Modified Lithotomy: A Surgical Position for Lower Extremity Wound Care Procedures in Super Morbidly Obese Patients. A Case Study

Index: Wound Management & Prevention 2019;65(7):30–34 doi: 10.25270/wmp.2019.7.3034

Abstract

Operative positioning of morbidly obese patients presents unique challenges and can cause complications, especially when the operative field involves the proximal lower extremity or genitoperineal region. PURPOSE: The purpose of this case study was to describe a modified lithotomy operative positioning technique that has helped the authors improve care of these patients. METHODS: Double-layer, foam padding at least 4 inches thick is secured to the top and sides of 2 small rolling preparation tables using 3-inch silk tape to create “lithotomy” leg holders, the operating table is raised appropriately, the abducted legs are placed onto the padded prep tables, and the footboard is carefully lowered to provide access to the groin and medial thighs. CASE STUDY: A super morbidly obese (body mass index 74), 47-year-old African American man with a history of hypertension and type 2 diabetes controlled on oral medications presented to the authors’ wound care clinic with 2 large, medial left thigh lymphedema masses requiring resection. Both procedures were successfully completed using the modified lithotomy position. No adverse events occurred. CONCLUSION: The modified lithotomy is easy to implement, does not require unique equipment, improves access to the surgical site, and may reduce the risk of complications. Larger and longer-term follow-up studies are needed to monitor the outcomes of this positioning technique.   

Introduction

Surgical management of morbidly obese patients requires extensive preoperative planning. Additional weight and body mass place additional burdens on staff and the patient, and improper technique can lead to injury of either party.1 One challenge requiring careful attention is positioning. Standard operating tables usually can hold 450 to 500 lb, and special bariatric tables and equipment may be needed in the super morbidly obese (body mass index [BMI] >50).1-3 Large scale retrospective studies have shown a larger body mass also can predispose patients to positioning-related nerve and soft tissue damage, necessitating careful consideration, particularly in longer procedures.2,4 Intraoperative nerve injury accounts for 15% of malpractice suits against anesthesiologists.5,6 Appropriate padding with viscoelastic polymer gels or 4 inches of foam must maintain pressure <32 mm Hg to reduce risk of intraoperative pressure ulcers.2,7-8 

Surgical intervention in the super morbidly obese can be challenging in any case because of issues related to access to the peritoneal and thoracic cavities as well as orthopedic intervention on the back or spine.7,9-11 Effective exposure of the operative site can be uniquely challenging due to body mass and patient habitus, including lower extremity wound care procedures near the genitoperineal region. Methods such as retracting soft tissues with tape, hanging tissue from overhead lighting, and connecting 2 operating room (OR) tables together have been suggested for operative positioning of morbidly obese patients; however, positioning for effective exposure of the genitoperineal region for surgical access in these morbidly obese patients remains largely undocumented.1,2 

Surgical intervention on hidradenitis suppurativa or proximal thigh lymphedema can be particularly burdensome in terms of operative positioning. Sistrunk wedge resection for proximal thigh lymphedema involves excising soft tissue and lymphedema masses down to underlying fascia, a procedure that can be particularly burdensome in the obese patient. The lierature12 has shown the use of more traditional techniques such as standard lithotomy or harnesses to elevate extremities to appropriate levels for operation, or even the presence of additional assistants during the procedure, can increase the cost burden in terms of operative time and equipment and risks injury to both the patient and operative staff. 

The purpose of this case study was to describe a modified lithotomy operative positioning technique that has helped the authors improve care of these patients. 

Methods

When the standard lithotomy position is predicted to fail to provide adequate exposure of the operative site, poses risks to patient or staff, or simply is not feasible due to extreme patient habitus, operating room staff prepare to use the “modified lithotomy” position. The patient is placed supine on a specialty bariatric table or 2 OR tables.1 Operative positioning is initiated once the patient is placed under general anesthesia. Double-layer foam padding at least 4 inches in thickness is secured to the top and sides of 2 small rolling preparation tables using 3-inch silk tape. These rolling stands serve as the “lithotomy” leg holders. The operating table is raised to the level of the stands, which are placed at the level of the mid to distal lower extremities. The abducted legs are placed onto the padded prep tables (see Figure 1), and the footboard is carefully lowered to provide access to the groin and medial thighs (see Figure 2A,B). The legs can be fully prepped into the operative field or segmentally exposed by placing a split sheet at the most distal aspect of the surgical site. The leg holders can be secured to the operating table with silk tape; the authors have found it advantageous to let them roll free to facilitate repositioning to access different operative sites during the procedure. Overabduction has not been an issue, because the downward weight of the extremity seems to limit inadvertent splaying of the extremity. The feet can be secured to the rolling prep tables with additional foam padding and silk tape if this will not interfere with the operative field. The surgeon can easily access the genitoperineal region by sitting on a stool or more anterior aspects of the thigh by standing between the 2 abducted legs. The modified lithotomy has become the most commonly utilized position in the authors’ practice for proximal thigh or perineal surgery in the super morbidly obese patient.

Case Report

Mr. K, a super morbidly obese (BMI 74), 47-year-old African American man with a history of hypertension and type 2 diabetes mellitus controlled on oral medications, presented to the authors’ wound care clinic in the fall of 2017 with complaints of a large, medial left thigh lymphedema mass that inhibited his ability to walk. He had a 10-year history of obesity and concurrent stage III lymphedema of his lower extremities, resulting in lymphostatic elephantiasis and the development of enlarging left thigh masses (see Figure 1). He had undergone complete decongestive therapy including scheduled lymphatic massage and compression leg wraps with a lymphedema therapist for 6 months prior to the authors’ evaluation. On examination, Mr. K had 2 large medial left thigh lymphedema masses with overlying fibrotic skin changes and hyperkeratosis. Compression seemed to control edema and stasis changes of the distal extremities. Mr. K had no open wounds on exam. Physicians decided to pursue staged Sistrunk wedge resection for the lymphedema masses to address lymphatic outflow, improve ambulatory status, and enhance patient hygiene.13

Mr. K was taken to the OR for the planned inpatient staged resection procedure. The larger, more proximal mass on left thigh was addressed first. The modified lithotomy position was utilized successfully in both resection operations (see Figure 2). The first procedure involved resection using bovie cautery and Harmonic Ultrasonic Scalpel (Stryker, Kalamazoo, MI) of the proximal mass. Following resection, negative pressure wound therapy (NPWT) set at -125 mm Hg of continuous pressure was applied to the resection site to allow drainage of additional lymphedema fluid to aid in closure. Three (3) days after the first stage of resection, Mr. K returned to the OR for removal of the NPWT system and the second procedure that involved resection of the more distal thigh mass, tissue rearrangement, and complex closure over 2 Blake drains of the entire resection site. A Prevena Plus Customizable (Acelity, San Antonio, TX) incisional wound NPWT device was applied at the conclusion of the second surgery, set to -125 mm Hg of continuous pressure and left in place for 7 days until removal, at which time the wounds were left open to air. In each procedure, placement of NPWT also was aided by the utilization of the modified lithotomy positioning. 

Mr. K was able to ambulate in the hall of the hospital without assistance before discharge home after 2 weeks of inpatient physical therapy. He had no signs of breakdown of the wound dehiscing upon discharge. Drains were removed in the outpatient clinic when wound fluid output decreased to <15 cc/day, approximately 3 weeks after the final operation. Mr. K lost a total of 50 lb in both soft tissue and fluid following the procedure and was very satisfied with the aesthetic and functional results of the operation (see Figure 3). Mr. K continued weekly visits with a lymphedema therapist and long-term follow-up with the wound care clinic for a year following surgery. Small regions of incision breakdown approximately 2 months after the operation were treated conservatively with local wound care and healed uneventfully. 

Discussion

The modified lithotomy position has been used successfully for several of the authors’ morbidly obese wound care patients undergoing surgical intervention on the proximal thighs or genitoperineal region. This case demonstrates the use of the positioning in one of the more challenging cases. When planning operative positioning, the surgeon must consider which method will most effectively expose the operative site while minimizing harm to the patient. 

Although the primary benefit of the modified lithotomy position is the excellent exposure to the operative site, other factors also may be advantageous. The modified lithotomy position allows an effective distribution of the extremity mass on a foamed surface, which reduces risk of soft tissue and nerve damage. In standard lithotomy, the possibility of compressive damage to the common peroneal, sciatic, obturator, and lateral femoral cutaneous nerves must be taken into account.7,14 Hip flexion and use of stirrups in the standard lithotomy have been shown in retrospective litigation reviews14,15 to be associated with lateral femoral cutaneous nerve damage and compartment syndrome. Proper use of the modified lithotomy should lead to lower rates of iatrogenic neuropraxia and other more permanent nerve injuries. 

In addition to nerve compression, the surgeon must be wary of lower back injury during movement of the legs in the lithotomy position. If both legs are not raised or lowered concurrently, torsion to the lumbar spine may occur.16 Although this risk remains in the modified lithotomy, it should be significantly decreased because the hips are not in significant flexion. Additionally, the lack of hip flexion prevents loss of the natural lordotic curvature of the lower back, which may be of significant benefit to patients with any history of low back pain.14 In general, overabduction of the legs has not been experienced in the authors’ practice. If that becomes an issue, securing the rolling prep tables to the operative table could be considered, but keeping them mobile has been helpful in many cases. 

It is important to note that operative positioning also can affect the patient’s physiology, which is of particular concern during administration of anesthesia. In the standard lithotomy position, leg elevation increases preload, which in turn increases cardiac output, blood pressure, and intracranial pressure. Particularly in obese patients, intra-abdominal pressure is increased, which can result in increased airway pressure, reduced chest wall compliance, and decreased functional residual capacity, predisposing the patient to hypoxia.17 Lowering the legs at the end of surgery then can decrease cardiac output and hypotension transiently, although sometimes severely.14 When the legs are not positioned in stirrups, as in the modified lithotomy, these problems are eliminated.

Limitations

Limitations of this technique for positioning are primarily centered on not being able to reposition the operative table during surgery. The operative table is locked after placement of the legs on the padded stands. Because the leg holders are a free-standing appliance, any movement of the OR table, including changes in elevation or rotation, risks nerve or musculoskeletal injury to the patient. Once the patient is initially positioned, the operating table must remain locked throughout the entirety of the operation. 

Conclusion

This case represents one possible application of the modified lithotomy position for Sistrunk wedge resection of lymphedema in a super morbidly obese patient. The authors have utilized this position for a variety of other morbidly obese patients requiring groin hidradenitis suppurativa excision or perineal skin grafting or altered for use in the prone position in patients with surgical sites in the more posterior region. Further data collection on the use and outcomes of this technique will be helpful in uncovering any unforeseen disadvantages of the position. Future applications of the modified lithotomy position could include patients with normal BMI undergoing lower extremity orthopedic surgery or proximal thigh flap harvest for plastic and reconstructive surgery such as the gracilis flap. 

As the rates of obesity and morbid obesity continue to rise, novel techniques and ideas will need to be developed to ensure quality care is consistently provided. In the authors’ experience, the modified lithotomy helps optimize care of morbidly obese patients who require proximal lower extremity or groin area surgery

Affiliations

Dr. Googe is a resident physician, University of Mississippi Medical Center, Division of Plastic Surgery, Jackson, MS. Ms. Lackey is a medical student, Florida State University College of Medicine, Tallahassee, FL. Dr. Arnold is a Professor and Chief, University of Mississippi Medical Center, Division of Plastic Surgery. Dr. Vick is an Associate Professor, University of Mississippi Medical Center, Department of General Surgery.

Correspondence

Please address correspondence to: Benjamin Googe, MD, 2500 North State Street, Jackson, MS 39216; email: bgooge@umc.edu.