Open Partial Nephrectomy

PAUL RUSSO

ROY MANO

SIMON KIMM

Over the last 20 years, partial nephrectomy (PN) has emerged as a critical operation for the treatment of renal cortical tumors (1). Advances in complex stone surgery (anatrophic kidney splits, hilar clamping, ice slush, collecting system repair), trauma surgery (renorrhaphy, proximal renal hilar control, vascular repair), and kidney donor transplantation (renoprotective solutions, ice slush) set the stage for the development of contemporary controlled open PN (2,3). The rapid development of the modern imaging modalities of ultrasound, computerized tomography (CT), and magnetic resonance imaging (MRI), often ordered for nonspecific abdominal or musculoskeletal complaints or during unrelated cancer care, leads to the detection of small, asymptomatic renal masses (1), which today account for 70% of all newly diagnosed renal tumors with a median tumor size of <4 cm (T1a). Approximately 20% of these tumors are benign (i.e., oncocytoma, fat poor angiomyolipoma), 25% are indolent malignancies with limited metastatic potential (i.e., papillary type 1, chromophobe, cystic renal cell carcinoma [RCC]), and 54% are the more potentially malignant clear cell carcinoma, but at the T1 size (<7 cm), metastasis would be realized in less than 10% of patients (1). These factors, which when taken together, led to the expansion of elective PN in the late 1990s (4). Once reserved only for the essential indications of tumors in an anatomically or functionally solitary kidney, today PN can effectively achieve the same local tumor control as radical nephrectomy (RN) while maximally preserving renal function and preventing or worsening preexisting chronic kidney disease (CKD) (5). Based on common preexisting medical conditions such as diabetes, hypertension, and cigarette smoking-induced vascular disease, CKD is present in up to 30% of patients with renal cortical tumors prior to operation and is associated with subsequent cardiovascular events, increased rates of hospitalization, and worse overall survival (6). The historical use of RN for all renal tumors, regardless of size, must now be considered obsolete. We have replaced the large and painful 11th rib flank incision associated with flank bulge and hernia in up to 50% of cases (7) with a mini-flank surgical incision (8,9) which, when coupled with our rapid recovery clinical pathway (10), is a highly effective approach to PN and leads to a median 2-day hospital length of stay. This approach is an excellent alternative to the expensive and technically complex minimally invasive (laparoscopic and robotic assisted laparoscopic) PN.

INDICATIONS FOR SURGERY

In the past 20 years, PN has transitioned from an operation only performed for essential conditions (tumor in a solitary kidney, bilateral tumors, tumor in patient with preexisting medical disease) to now include elective conditions (tumor in a patient with a normal contralateral kidney). Initially, elective PN was restricted to tumors of 4 cm or less (11,12,13), but with increasing experience, surgeons approached T1b and T2-T3a tumors (14,15,16,17) when technically feasible with similar oncologic outcomes compared to RN. With the advantage of intraoperative ultrasound (18), it is now also possible to resect impalpable endophytic, renal sinus, multifocal, and perihilar tumors which previously would have been treated only by RN.

PN may also be advocated as a salvage procedure after failed thermal ablation attempts, as “redo” procedures for recurrent renal tumors in both the sporadic and hereditary RCC setting, and uncommonly as a cytoreductive procedure in metastatic patients with a small renal tumor prior to the initiation of systemic therapy. These indications pose a greater surgical challenge than primary PN with more potential for blood loss and conversion to RN if, for technical reasons, PN cannot be executed. In essence, today, all patients with kidney tumors are scrutinized closely for consideration of PN, and only those where the majority of the kidney is replaced by tumor or those with massive tumors with regional adenopathy and/or renal vein/inferior vena cava extension will undergo RN.

ALTERNATIVE THERAPIES

Patients with small renal tumors are eligible for active surveillance, or surgery (PN or RN) by either open or minimally invasive approaches. In general, for older patients (>75 years) or those with serious medical comorbidities and a limited life expectancy, active surveillance is recommended due to the low likelihood of disease progression in the patient’s lifetime and significant risks associated with surgical intervention (19,20). Active surveillance, even with small renal tumors, is more difficult to propose in young and healthy patients with a long life expectancy because on rare occasions, rapid tumor growth and metastatic disease can ensue. Thermal ablation (radiofrequency ablation [RFA], cryoablation) procedures are associated with far greater rates of persistent and recurrent disease (21), and patients deemed likely candidates for ablation are generally the same that we recommend for active surveillance.

PREOPERATIVE PLANNING AND PATIENT PREPARATION

Preoperative assessment begins with a careful history, with a special emphasis on medical comorbidities affecting the cardiovascular and renal function, and a thorough physical examination. Correctable and potentially life-threatening cardiovascular disease should be addressed (i.e., carotid endarterectomy, coronary revascularization) prior to PN. A baseline
calculation of estimated glomerular filtration rate (eGFR) should be done using the following web link for the MDRD or CKD-EPI equation (http://www.nephron.com/MDRD_ GFR.cgi). Preoperative renal protocol CT imaging must have noncontrast views in search of microscopic fat or pseudo enhancement with volume averaging to exclude benign angiomyolipoma and hemorrhagic cyst, respectively, which would warrant nonoperative management (22). A contrast-enhanced study (MRI, CT, or renal perfusion/excretion nuclear scan) is required to document bilateral renal function. Renal ultrasound with Doppler imaging is an effective way to assess the lesion for vascular flow (23), can fully characterize cystic lesions, and serves as a template for intraoperative ultrasound in order to locate small, endophytic, impalpable subcortical renal tumors (18). In general, preoperative renal tumor biopsy is considered only when this information could dramatically change management if, for example, an infiltrative mass is identified and a renal lymphoma is suspected.

We conduct in-depth discussions describing the anticipated degree of surgical difficulty in completing an anticipated PN, the renal functional result, and a full description of potential complications including bleeding, infection, urinary fistula, the need for a prolonged perinephric drainage, and conversion to RN, if for technical reasons, a PN cannot be executed. A preoperative nomogram can reassure patients with small renal masses that a favorable long-term prognosis is achievable with an effective resection (24). A nephrometry scoring system (R.E.N.A.L.) can categorize the degree of surgical difficulty for a planned PN (25). The likelihood of a subsequent ipsilateral (<5%) or contralateral (<5%) tumor recurrence in a patient’s lifetime and the need for lifetime kidney imaging is also discussed.

FIGURE 2.1 Patient positioning. The patient is carefully positioned in standard flank position, using approximately 50 to 60 degrees of flank elevation. The patient should be centered on the operating table with the upper brim of the iliac crest below the table break to avoid direct gluteal pressure. An axillary roll is placed. A beanbag is used to hold the patient in position. After rolling to the flank position, the legs are flexed and separated by two pillows, avoiding adduction strain on the upside leg. The leg in contact with the table is flexed to a greater degree with additional padding placed at the hip, knee, and ankle pressure zones. The downside arm is cushioned on an armboard with the elbow flexed. The upside arm is suspended in a foam cradle in neutral position. The patient is secured to the table at the hip with 2-inch fabric tape. Padding is used on the skin such that the adhesive surface of the tape does not come in contact with the skin. A padded safety strap is used to further secure the lower extremities. ASIS, anterior superior iliac spine.

The anticipated length of the hospital stay and postoperative recovery are described. The importance of walking on the first postoperative day (14 laps around the floor is a mile) to prevent deep venous thrombosis and deep breathing with incentive spirometry to prevent atelectasis and pneumonia is stressed. We rapidly advance patients to a regular diet with conversion to oral pain medication and continued vigorous walking by the second day. The vast majority of patients are discharged on the second postoperative day (10). This regimen of vigorous walking continues at home with a switch to over-the-counter pain medications as soon as possible. We encourage three protein-rich meals per day to maximize healing and continued walking at least 30 minutes twice per day with avoidance of heavy lifting for 3 months.

SURGICAL TECHNIQUE

Supra-11th Rib Mini-flank Surgical Incision

The traditional 11th rib flank incision provided wide exposure, but patients complained of significant postoperative pain, prolonged recovery, and for up to 50%, an uncomfortable and unsightly flank bulge usually caused by denervated muscle often with associated paresthesia and neuralgic pain (7). For the surgeon, rib resection and closure of this large incision also added significant operating time. We developed the “mini-flank” supra-11th rib incision as an effective alternative to standard flank incision or laparoscopic PN (8,9).

The patient is placed in the standard flank position (Fig. 2.1). An 8- to 10-cm extraperitoneal incision is made between the bed of the 10th and 11th ribs (Fig. 2.2). Intercostal ligaments
are sharply divided, allowing for further separation of the ribs and rapid exposure to the retroperitoneum without rib resection (Fig. 2.3). The latissimus dorsi, external oblique, and internal oblique muscles are transected, and the transversus abdominis is divided in the direction of its fibers while preserving the intercostal neurovascular bundle. Using blunt dissection, the peritoneal cavity is mobilized medially, the perinephric soft tissues laterally, and the diaphragmatic fibers and pleural superiorly. A small incision in the plane between the soft tissues overlying the psoas muscle (Fig. 2.4A) and Gerota fascia is then bluntly developed, creating a flap of peritoneum (Fig. 2.4B) that is retracted medially and exposes the kidney, ureter, and ipsilateral great vessel (vena cava on the right, aorta on the left). The Bookwalter retractor (Codman and Shurtleff, Inc, Raynham, Massachusetts) is placed using the bladder blade to retract the 10th rib and peritoneal flap superiorly and medially which allows the kidney and perinephric soft tissues to move caudally into the wound. The short right-angle blade retracts the 11th rib laterally. Following blunt dissection of the intestinal contents, deeper malleable blades are placed to expose the great vessels by retracting intestines medially (Fig. 2.5). The ureter is isolated with a yellow vessel loop (Fig. 2.6A),
and careful division of lymphatic channels and soft tissues allow isolation of the renal artery and vein with red and blue vessel loops, respectively (Fig. 2.6B). For tumors located in a polar position, once the renal hilar vessels are isolated, it is not necessary to mobilize the opposite pole from the surrounding soft tissues (and adrenal for upper pole). We do not perform mass renal pedicle clamping with vascular clamps during cold ischemia. On the left side, the gonadal and adrenal veins are usually ligated and divided to liberate the tethered renal vein to allow enhanced upward lifting of the kidney and improved access to the renal artery. The upward mobilization of the kidney decreases venous bleeding later during the tumor resection and facilitates identification and repair of rents in renal sinus veins (Fig. 2.7). The upper pole of the kidney is separated from the adrenal using blunt dissection, and perforating vessels are ligated and divided with the LigaSure (Covidien, Mansfield, Massachusetts).

FIGURE 2.2 Mini-flank incision. An 8- to 10-cm extraperitoneal incision is made between the bed of the 10th and 11th ribs. White broken line, lower boundaries of the thoracic cage.

FIGURE 2.3 Intercostal ligaments are cut, allowing more space between ribs and easy access to retroperitoneum. The latissimus dorsi, external oblique, and internal oblique muscles are transected, and the transversus abdominus is divided in the direction of its fibers.

FIGURE 2.4 A: A small incision is made in the soft tissues posterior to Gerota fascia which overly the psoas muscle (Ps). B: Gerota fascia is then bluntly developed and gathered with the peritoneum to create a flap of tissue (asterisk) that is retracted medially for exposure.

FIGURE 2.5 The Bookwalter retractor is deployed to assist in exposure. Superior and medial retraction of the 10th rib and peritoneal flap is provided by the bladder blade. The short right-angle blade provides lateral retraction of the 11th rib. Right-angle or malleable blades provide inferior and medial retraction.