Laparoscopic Resection of Renal Masses


Benign

Malignant

Angiomyolipoma

Wilms’ tumor (unilateral or bilateral)

Renal pseudotumor

Clear cell tumor

Metanephric adenoma

Renal cell carcinoma

Multicystic nephroma

Mesoblastic nephroma

Reninoma

Rhabdoid tumor

Ossifying renal tumor of infancy

Multilocular cystic nephroma





Anesthetic Consideration s


Laparoscopy is generally well tolerated by children; however, several anatomic and physiologic differences exist in comparison to adults (see Chap. 1).

Neonates and infants exhibit reduced ventricular compliance, possess a short trachea, and incur increased intra-abdominal pressure resulting in a decrease in functional residual capacity. Hypoxia or visceral stimulation can potentially elicit bradycardia as well [9].

Laparoscopic renal surgery in children can be performed by both retroperitoneal and transperitoneal approaches. The retroperitoneal approach may lead to increased CO2 absorption and elevated pulmonary artery pressure. These effects are primarily seen in children with central nervous system and/or cardiorespiratory dysfunction [9, 10].


Laparoscopic Radical Nephrectomy



Transperitoneal Approach



Patient Positioning


One must take into consideration patient body habitus, size/location of the renal lesion, and exposure needs when deciding on patient positioning (Fig. 50.1). Positioning can vary from supine to partial flank to full flank. Most cases can be completed in the supine position with a bump placed under the side of the lesion.

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Fig. 50.1.
Patient positioning for Laparoscopic Nephrectomy. From Valla JS. Basic Technique: Retroperitoneoscopic Approach in the Lateral Position. In: Endoscopic Surgery in Infants and Children. Bax KMA, et al., eds. 2008:633–638. Reprinted with permission from Springer.

In order to increase operative space, the bed may be flexed and/or kidney rest elevated to help widen the angle between the lower ribs and pelvic brim. This may be less beneficial in the younger population due to limited body habitus.

Proper padding of boney sites and soft tissues to ensure patient safety is imperative. The patient is strapped with sturdy cloth tape to allow stability and safety with bed movement.


Port Placement


We find the most predictable point of entry into the peritoneal cavity to be through the umbilical region using an open or Veress needle technique (Fig. 50.2). Either a 5-mm or 10-mm laparoscopic trocar is placed with a 0° scope within the port to allow for direct visualization during entry when using the Veress needle.

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Fig. 50.2.
Trocar placement for LN. From Shenoy MU. Total Nephrectomy: Transperitoneal Approach. In: Endoscopic Surgery in Infants and Children. Bax KMA, et al., eds. 2008:639–642. Reprinted with permission from Springer.

Insufflation is started at a pressure of 12 mmHg or less dependent on the age and weight of the patient, with incremental flow of 1–3 L/min. If necessary, higher pressure (up to 15 mmHg) can be used for port placement, after which the pressure should be decreased to the lowest pressure that maintains good visualization.

Two accessory ports are then placed under direct observation after anesthetizing the skin. One working port is placed along the ipsilateral rectus border. The third port can be placed in the midline below the xiphoid. When necessary, an additional port to allow for liver or splenic retraction can be placed subxiphoid as well. Alternatively the original subxiphoid port can be used for retraction and an additional port placed inferiorly based on the anatomy.


Colon Mobilization


We begin with mobilization of the colon overlying the kidney while maintaining the lateral renal attachments.

The colon is dissected along the white line of Toldt from the splenic flexure on the left or hepatic flexure on the right. Dissection can be performed using harmonic scalpel, cold scissors, or cautery.

Once the ureter is identified as it courses over the psoas muscle, it is followed cephalad to the renal hilum and can be used for retraction. All effort is made to keep Gerota’s fascia intact when removing a possible malignant lesion.


Renal Hilum


The ureter and gonadal vein are secured and divided. The hilum should be carefully dissected using gentle technique. Dissection can be performed using a variety of devices. The author’s preference is to initially use harmonic scalpel for gross dissection, followed by hook electrocautery for fine dissection using a suction/irrigator with hook attachment. The latter device allows for precise dissection and suction without repeatedly changing instruments.

Efforts should be made to isolate the artery first and vein second. Once isolated, the vessels can be ligated separately with clips. If a 12-mm port is in place, a laparoscopic stapling device with vascular staple load can be used. When difficulty is encountered separating the artery and vein, the entire hilum can be stapled as one, provided adequate visualization. It is important to remember that one can staple or clip across staples, but one cannot staple across previously placed clips.

Secondary renal hilar vessels should be identified and controlled appropriately, with care taken to observe for and control adrenal branches.


Specimen Removal


In the setting of benign indications , the kidney can be extracted from the umbilical region. A 5-mm lens allows visualization through a working port during extraction. The specimen can be divided into smaller pieces laparoscopically or morcellated within a specimen retrieval bag.

If the specimen is possibly malignant or too large for morcellation, a retrieval bag can be deployed and the specimen removed through a Pfannenstiel incision or extension of a port site(s).


Complication s


The smaller working space in pediatric patients yields an increased risk of abdominal organ or vascular injury during laparoscopic surgery. Although rare, injury occurring during placement of the initial trocar is a likely cause [11]. Injuries detected intraoperatively should be addressed and repaired. Laparoscopic experience has been found to be the strongest predictor of complication rate during laparoscopic urologic procedures [12].


Retroperitoneal Approach


This approach is preferred by many surgeons due to its convenient access to the renal hilum. The limited retroperitoneal fat in many children can further enhance this advantage. Due to unfamiliar anatomy, fewer landmarks, and limited space, this approach can be technically challenging and is best reserved for experienced laparoscopic surgeons or those who have specific training in its use. Retroperitoneal techniques can be performed in either the lateral or prone position. Both approaches have been reported to have similar outcomes and complication rates [13].


Lateral Approach


We place the patient in the flank position and flex the bed to aid in widening the operative field (Fig. 50.3). The patient is safely secured and pressure points are appropriately padded.
Oct 25, 2017 | Posted by in PEDIATRICS | Comments Off on Laparoscopic Resection of Renal Masses
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