Robotic Partial Nephrectomy in a Morbidly Obese Patient: A Case Report

ABSTRACT

Laparoscopic surgical management of obese patients can be challenging. Data is limited on the use of robotic-assisted laparoscopic nephrectomy and partial nephrectomy in the management of renal masses in the obese population. We report a case of a morbidly obese white male with a BMI of 56.6 kg/m2 who underwent an uncomplicated robotic partial nephrectomy for 2 right-sided renal masses. We conclude that robotic partial nephrectomy is feasible for the management of renal masses in morbidly obese patients.


Adam B Althaus, Brad M Lake, Sam B Bhayani, R Sherburne Figenshau

Washington University School of Medicine, Department of Surgery, Division of Urologic Surgery, Missouri, United States

Submitted: January 24, 2012 - Accepted for Publication: April 12, 2012


KEYWORDS: Robotic partial nephrectomy, obese

CORRESPONDENCE: Adam Althaus, Washington University School of Medicine, Department of Surgery, Division of Urologic Surgery, 4960 Children’s Place, Campus Box 8242, St. Louis, MO 63110, United States ().

CITATION: UroToday Int J. 2012 June;5(3):art 15. http://dx.doi.org/10.3834/uij.1944-5784.2012.06.02

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INTRODUCTION

Obesity is common in the United States; recent reports indicate a prevalence of 32.2% in adult men and 35.5% in adult women [1]. Evidence shows increased body mass index (BMI) is associated with an increased risk of renal cell carcinoma [2]. Surgical management of obese patients can be technically challenging and has been associated with increased complications. Mendoza et al. reported increased complication rates for markedly obese patients undergoing laparoscopic urologic surgery when compared to non-obese patients [3]. However, more recent literature reports surgery complication rates are no different for obese patients requiring laparoscopic nephrectomy when compared to non-obese patients [4,5]. Laparoscopic surgery has also been shown to be a safe option for obese patients undergoing partial nephrectomy. Naeem et al. found robotic-assisted partial nephrectomy to be safe in obese patients (BMI 30.3 to 49 kg/m2) [7]. We report a case of a robotic-assisted partial nephrectomy for a renal mass in a markedly obese patient with a BMI of 56.6 kg/m2.

CASE REPORT

A 42-year-old morbidly obese white male with a BMI of 56.6 kg/m2 (height: 73 in, weight: 495 lb) was referred for 2 right renal masses incidentally found on a nephrolithiasis work-up. The patient denied associated symptoms. On the computed tomography (CT) imaging, a 15 mm cystic lesion was seen in the superior pole and a 4.2 cm cystic lesion was seen in the inferior pole. Due to the patient’s body habitus, the masses could not be completely characterized on CT in spite of the administration of intravenous contrast (Figure 1). A renal ultrasound was obtained, which confirmed the 4.2 cm complex, predominately cystic, exophytic lesion with septations in the inferior pole of the right kidney; however, the lesion in the superior pole was not visualized (Figure 2). Given the possibility of renal cell carcinoma, the patient was counseled on treatment options, including radical nephrectomy, partial nephrectomy, percutaneous management with renal cryoablation or radiofrequency ablation, biopsy, and observation with repeat imaging. We decided to observe and obtain a follow-up ultrasound within 6 months. Weight loss was emphasized to both decrease risk of perioperative morbidity if surgery was required, and to improve future imaging.

Six and 12 month follow-up ultrasounds showed a stable 4 cm lesion in the inferior pole of the right kidney. The patient opted for continued observation. Six months later the patient presented with right-sided flank pain. At this point he had lost 66 pounds (BMI: 56.6 kg/m2), and his ultrasound showed the mass was stable at 4.2 cm in its maximum diameter. However, given the new onset of pain, the patient elected to undergo right laparoscopic robotic-assisted partial nephrectomy.

Right robotic-assisted laparoscopic partial nephrectomy and cyst excision were performed. After induction of anesthesia, intubation, and oral gastric tube placement the patient was easily transferred from his hospital bed onto the operating table with the aid of an inflatable transfer mattress. Attachments to widen the operating table had to be placed to accommodate the patient. He was carefully positioned into the left lateral decubitus position. All pressure points were padded and an axillary roll was placed to avoid brachial plexus injury. The abdomen was prepared and draped in the typical sterile fashion. Veress needle insufflation was performed. Due to the patient’s obesity, the laparoscopic ports were shifted laterally (Figure 3) and long robotic trocars were utilized. The patient had a distended right colon, which occupied a significant portion of the abdominal space. In addition, there was a large amount of perinephric adipose tissue. After mobilization of the right colon along the line of Toldt, the kidney was retracted laterally and the lower pole was exposed. Intraoperative ultrasound was used to identify the lower pole renal mass. The mass was largely exophytic. While dissecting along the lower pole of the kidney, a plane between the mass and the kidney became apparent. Given the patient’s obesity, gaining exposure to the hilum proved challenging. Also, to avoid prolonged warm ischemic time given the presence of 2 masses, we decided to further develop the plane between the mass and the kidney without hilar control. This plane was advanced, and the mass was enucleated from the kidney. Hemostasis was maintained throughout the resection of the mass. Once the mass was resected the base was thoroughly cauterized followed by placement of the Floseal. The mass was placed into an entrapment sack and placed out of the operative field.

The anterior aspect of the upper pole of the kidney was then exposed to examine the additional mass that was identified by the initial CT. The mass identified appeared to be a simple cyst by ultrasound, without an identifiable solid component. Given the presentation of abdominal pain, to minimize confounding factors in follow-up care, the decision was made to excise the cyst. The procedure was done entirely off clamp. The base of the defect was cauterized. The pneumoperitoneum was decreased to 5 mm Hg and the kidney was inspected to ensure hemostasis. The abdomen was inspected. The fascia was not closed at any port site. Skin was reapproximated with a stapling device. Total operative time was 2 hours and 46 minutes. There were no intraoperative complications, and he tolerated the procedure well. Blood loss was estimated to be 100 to 150 ml. The patient’s hospital course was uneventful and he was discharged home postoperative day 1. At home, the patient’s extraction incision opened, requiring home wound care. This was due to the patient removing staples from his incision without consulting the surgical team. He followed up 6 weeks after surgery and was doing well.

Final pathology was a 3.2 cm, T3a (tumor focally penetrated the capsule into perinephric fibroadipose tissue), Fuhrman grade II-III, clear cell carcinoma in the right, lower pole, and a 3.2 cm simple cyst in the right, upper pole.

DISCUSSION

Given the high prevalence of obesity in the United States and the increased risk of renal cell carcinoma (RCC) in obese patients, optimal surgical management for this patient population needs to be defined. Historically, marked obesity was considered by some to be a relative contraindication to laparoscopic surgery [3]. In 1996, Mendoza et al. reported increased complication rates for markedly obese patients (mean BMI: 35.1 kg/m2) undergoing a variety of laparoscopic urologic surgeries when compared to non-obese patients [3]. Complications included conversion to open surgery, trocar injuries to abdominal wall vessels, bladder injury, peripheral nerve injury, DVT, wound seroma, nephrocutaneous fistula, and incisional hernia.

With technological advancement and increased surgeon experience, obesity is no longer considered a barrier for laparoscopic surgery. Recent literature on laparoscopic nephrectomy indicates that the procedure is not associated with increased complication rates for obese patients when compared to non-obese patients [4,5]. Rogers et al. demonstrated that robotic nephrectomy is recognized as a safe and feasible option for minimally invasive nephrectomy [8]. While not specifically studying obese patients, Rogers et al. had a relatively obese patient cohort with a mean BMI of 31 kg/m2 and were successful with nephrectomy in patients with a BMI as high as 44 kg/m2.

Several studies have indicated laparoscopic surgery is a reasonable option for nephrectomy in obese patients; however, these studies categorize patients as obese or not obese based on varying BMI cutoff points. It is important to consider the degree of obesity when evaluating the risks of surgery. Gong et al. were the first to study how the degree of elevated BMI affects laparoscopic renal surgery [9]. They found no statistical difference in outcomes for patients with increased BMI. Logistic regression analysis indicated there may be an association with the degree of obesity and an increase in both operation time and intraoperative complications. Therefore, patients in the extremes of obesity need to be counseled on potential increased risks of intraoperative complications and operative times, as well as conversion to an open procedure. In this case, to decrease the patient’s risks of surgical complications it was beneficial to monitor the mass and allow the patient time to lose weight.

When appropriate, nephron-sparing surgery (NSS) is the preferred management of patients with RCC [10]. However, this may increase the complexity of an already difficult surgery in the obese population. Colombo et al. demonstrated laparoscopic partial nephrectomy as a safe option for obese patients [6]. Naeem et al. compared 49 obese patients with an average BMI of 36.2 kg/m2 (range 30.3 to 49) to 48 non-obese patients with an average BMI of 25.7 kg/m2 (range 20.5 to 29.7) who underwent robot-assisted partial nephrectomy. There were no differences in intraoperative or postoperative complications. They found obese patients had a larger estimated blood loss (150 versus 100 ml) and an insignificant trend toward longer median operative time and median warm ischemia time [7]. To our knowledge there is no report of robotic-assisted partial nephrectomy in a patient with a BMI as high as 56.6 kg/m2. This case demonstrates that even in morbidly obese patients, robotic-assisted partial nephrectomy is a reasonable therapeutic option. Long-term follow-up is necessary to assess an oncological outcome, but we anticipate that it would be similar to robotic partial nephrectomy in non-obese persons. Ten months after the surgery the patient has no evidence of tumor recurrence.

This case also demonstrates key modifications that must be made when approaching robotic-assisted surgery in obese patients. The aid of an inflatable mattress allows for easier transfer onto the operating table. Additional attachments can be helpful to widen the operating table. The patient is prepped in the lateral decubitus position, which leads to a lateral shift of the patient’s pannus. Thus, trocar sites need to be shifted laterally, away from the umbilicus to account for this (Figure 3). Due to the patient’s thick subcutaneous tissue layer and oftentimes larger abdominal cavity, longer trocars should be available to allow manipulation of deeper structures. Also, given the potential for longer operation time, care should be taken when positioning and securing the patient to prevent tissue necrosis and rhabdomyolysis. Our patient experienced minor wound complications at the extraction site during recovery. There is currently no consensus on closing port fascia in obese patients. Phillips et al. analyzed studies of obese patients who underwent bariatric procedures. They found some studies indicate closing the fascia predisposes patients to incisional hernias, while other studies show no difference in incisional hernias with or without fascial closure [11].

REFERENCES

  1. Flegal, K. M., M. D. Carroll, et al. (2010). “Prevalence and trends in obesity among US adults, 1999-2008.” JAMA 303(3): 235-241. 
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  2. Bergstrom, A., C. C. Hsieh, et al. (2001). “Obesity and renal cell cancer--a quantitative review.” Br J Cancer 85(7): 984-990. 
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  3. Mendoza, D., R. C. Newman, et al. (1996). “Laparoscopic complications in markedly obese urologic patients (a multi-institutional review).” Urology 48(4): 562-567. 
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  4. Kapoor, A., A. Nassir, et al. (2004). “Comparison of laparoscopic radical renal surgery in morbidly obese and non-obese patients.” J Endourol 18(7): 657-660. 
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  5. Fugita, O. E., D. Y. Chan, et al. (2004). “Laparoscopic radical nephrectomy in obese patients: outcomes and technical considerations.” Urology 63(2): 247-252; discussion 252. 
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  6. Colombo, J. R., Jr., G. P. Haber, et al. (2007). “Laparoscopic partial nephrectomy in obese patients.” Urology 69(1): 44-48. 
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  7. Naeem, N., F. Petros, et al. (2011). “Robot-assisted partial nephrectomy in obese patients.” J Endourol 25(1): 101-105. 
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  8. Rogers, C., R. Laungani, et al. (2008). “Robotic nephrectomy for the treatment of benign and malignant disease.” BJU Int 102(11): 1660-1665. 
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  9. Gong, E. M., M. A. Orvieto, et al. (2007). “Analysis of impact of body mass index on outcomes of laparoscopic renal surgery.” Urology 69(1): 38-43. 
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  10. Campbell, S. C., A. C. Novick, et al. (2009). “Guideline for management of the clinical T1 renal mass.” J Urol 182(4): 1271-1279.
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  11. Phillips, E., D. Santos, and S. Towfigh. (2011). “Working Port-Site Hernias: To Close or Not to Close? Does it Matter in the Obese?” Bariatric Times 8(6):24-30.
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