Pediatric nephrectomy via retroperitoneal approach

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摘要

The description of the pediatric nephrectomy via retroperitoneal approach covers all aspects of the surgical procedure used for the management of dysfunctional kidney in children.
Operating room set up, position of patient and equipment, instruments used are thoroughly described. The technical key steps of the surgical procedure are presented in a step by step way: dissection of kidney, freeing of the kidney, extraction.
Consequently, this operating technique is well standardized for the management of this condition.

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刊物

2003-02

普通的

最愛

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數位出版

WeBSurg.com, Feb 2003;3(02).
URL: http://www.websurg.com/doi-ot02en280.htm

Pediatric nephrectomy via retroperitoneal approach

1. Introduction

Retroperitoneoscopy refers to the minimally invasive approach to the retroperitoneal space, developed in the early 1990s (Gaur et al., 1993; Gaur, 1995). Due to cosmetic, functional, and immunologic advantages, this approach has been gaining popularity for pediatric urologic procedures involving the upper urinary tract, which are usually approached retroperitoneally. However, compared to transperitoneal laparoscopy, retroperitoneoscopy has the disadvantage of a smaller working space, especially in children. This can hinder trocar placement and mobility. Some advantages include the avoidance of postoperative paralytic ileus, intestinal adhesions, and omental eviscerations. Retroperitoneoscopy also simplifies the approach to the kidney, which is subsequently not obstructed by the intra-abdominal organs, especially the bowel.

Retroperitoneoscopy has become an approach of choice for minimally invasive surgery of the kidney, ureters, adrenal gland and, in some cases, the aorta (Clayman et al., 1991). Unlike the peritoneal or pleural cavity, the retroperitoneal space is not an actual anatomical space. It therefore requires the creation of a ‘neocavity’ to obtain adequate working space.

2. Anatomy

• Anterior relationships

The kidneys are covered anteriorly by perirenal fat and the posterior parietal peritoneum with intraperitoneal contents.
- right kidney:
1. Inferior surface of liver
2. Second portion of duodenum
3. Hepatic flexure of colon
- left kidney:
4. Tail of pancreas
5. Inferior surface of spleen
6. Splenic flexure of colon

• Posterior relationships

1. Psoas muscle
2. Quadratus lumborum muscle
The posterior surface of the kidneys lies on a muscular plane comprised of the psoas muscle medially and the quadratus lumborum muscle laterally.

• Vascular structures

1. Left renal artery (arises from aorta at vertebral level L1/L2)
2. Left renal pelvis
3. Left lower pole artery
4. Left upper pole artery
5. Left inferior adrenal artery
6. Left adrenal vein
7. Left renal vein
The renal pedicle is comprised of the renal artery and its branches, the renal vein, and the lymphatic vessels surrounding the initial portion of the renal pelvis.

3. Indications

The indications for simple nephrectomy or nephroureterectomy apply to the retroperitoneoscopic approach: dysfunctional kidney due to post-obstructive pathology or vesicoureteral reflux, hypotrophic kidney with renovascular hypertension, or polycystic kidney, for example (Gaur, 1995; Peters, 2000; Yao et al., 2000).

The only relative contraindications are:
- recent episodes of pyelonephritis;
- xanthogranulomatous pyelonephritis;
- history of severe renal trauma that could lead to difficulties in dissection and in the creation of a working space.

4. Operating room set-up

• Patient

The child is placed in lateral decubitus position, on a lumbar support or an angulated table to open the working space between the 12th rib and the iliac crest.
Depending on the patient’s weight and age, either wide adhesive tape or cushions are used to prevent the body from moving.
Pressure points are protected.

• Team

1. Surgeon
2. Assistant
3. Scrub nurse
The surgeon and assistant stand behind the patient.
The surgeon stands at the feet and the assistant stands at the head of the patient during the vascular approach and freeing of the kidney. There may be a change in positions during the ureterectomy.

• Equipment

1. Video unit
2. Instrument table
3. Electronic devices (electrocautery, ultrasonic scalpel), suction-irrigation device
4. Anesthetic equipment
The video unit is located opposite the surgeon and assistant, at the level of the patient’s head.
It must be possible to move the video unit down toward the patient’s feet during the procedure.

5. Trocars/instruments

• Optical

1. Mid-axillary line
2. Sacro-lumbar paravertebral muscles
3. 12th rib
4. Iliac crest
A 10 or 12 mm trocar is inserted at the tip of the 12th rib.

• Posterior trocar

A 5 or 3 mm trocar is positioned on the lateral edge of the sacro-lumbar muscles, 2 to 3 cm above the iliac crest, to allow for adequate mobility of the instruments.
This trocar accommodates:
1. Grasping forceps
2. Atraumatic graspers
3. Dissector
4. Ultrasonic dissectors
5. Bipolar forceps
6. Ultrasonic scalpel
7. Suction-irrigation device

• Anterior trocar

A 5 mm trocar is introduced on the mid-axillary line, 2 to 3 cm above the iliac crest. It accommodates:
1. Grasping forceps
2. Dissector
3. Scissors

6. Trocar placement

• Optical trocar

1. Kidney
2. Parietal peritoneum
3. Psoas major muscle
4. Kelly forceps
5. Beginning of dissection
After making a 10 to 12 mm incision at the tip of the 12th rib, the musculofascial planes are dissected and exposed using Farabeuf retractors with a long, narrow blade. The fascia and perirenal fat are incised. A gauze wad (about 8 mm) placed on a Kelly forceps is introduced. The dissection begins with the gauze wad, caudally and posteriorly, until the anterior surface of the psoas major muscle is reached. The dissection is then continued along this muscle, as inferiorly as possible. The detachment is carefully pursued anterior to the psoas major muscle, permitting retraction of the parietal peritoneum.
A 10 mm trocar is placed. A purse string is fashioned. The trocar is attached to the wall by a suture to prevent gas leak and to exert traction on the wall, as is done in parietal suspension techniques.
A 10 mm, 0° laparoscope is introduced.
The laparoscope is introduced and the pneumodissection of the retroperitoneal space can begin, following the plane of the psoas major muscle.

• Posterior trocar

1. Creation of working space
2. Electrocautery scissors via posterior trocar
3. Anterior surface of psoas major muscle
The posterior operating trocar is introduced as soon as possible. After making the skin incision, a fine grasper (Kocher or Halstead) creates a passage in the musculofascial plane under laparoscopic guidance, enabling the surgeon to safely place the trocar without having to force it in. The creation of the working space is greatly facilitated by using a combination of the laparoscope, gas insufflation, and the electrocautery scissors inserted through the posterior trocar.
A 5 mm laparoscope is introduced through this trocar at the end of the procedure during extraction of the operative specimen.

• Anterior trocar

1. Psoas major muscle
2. Musculofascial plane
3. Anterior trocar
The parietal peritoneum is retracted anteriorly with a fenestrated atraumatic grasper to allow for the insertion of the anterior operating trocar under visual control without rupturing the peritoneum.

7. Dissection of kidney

1. Parietal peritoneum
2. Working space
3. Inferior pole of left kidney
4. Left ureter
5. Psoas major muscle
6. Posterior dissection
It is mandatory to identify the ureter before approaching the kidney and freeing its posterior surface. The posterior surface of the kidney is progressively dissected free from the perirenal fat. This step involves no particular technical difficulties. The dissection begins on the posterior surface, and is pursued to the level of the poles. During dissection of the superior border, the surgeon must remain in constant contact with the renal capsule to avoid getting lost in the adrenal fossa.

Total mobilization of the kidney is not advisable. The kidney should remain attached by its anterior peritoneal attachments. This facilitates the exposure of the renal pedicle and avoids having to immobilize an instrument that would otherwise be allocated solely for maintaining traction on the kidney.

Initial dissection of the anterior surface of the kidney involves a risk of peritoneal rupture:
- if a very slight gas leak occurs, the surgeon can choose between a simple repair, achieved by fashioning a purse string with absorbable suture, or evacuating the leak with an intraperitoneal needle, which prevents the retroperitoneal space from caving in.
- if there is extensive rupture of the peritoneum, the surgeon must warn the anesthesiologist of the passage from a retroperitoneal approach to an intraperitoneal procedure, with the risk of rapid increase in the ETCO2 and ventilation pressures. Furthermore, the area of the rupture must be enlarged considerably to avoid being continually hindered by the peritoneal flap.
In our experience, rupture of the peritoneum has never led to the need for conversion.

8. Freeing of the kidney

• Renal pedicle

1. Dissection of renal pedicle
2. Renal pedicle
3. Posterior surface of kidney
4. Left ureter
5. Psoas major muscle
6. Parietal peritoneum
The vessels of the renal pedicle are approached posteriorly, below the kidney. The dissection is carried out as low as possible, away from the kidney and its arterial and venous hilar branches. If possible, the artery is divided first.
Intracorporeal or extracorporeal ligation is performed with absorbable suture. Alternatively, clips can be used. The same technique is then used to ligate the vein. In children, depending on the size of the vessels, the nephrectomy of a hypotrophic, damaged kidney can be done after simple electrocautery of the vessels with either bipolar forceps or ultrasonic scalpel.
In case of difficulty in exposing the vessels, the ureter is an easy landmark to find. It should be followed cranially, up to the renal hilum.

• Freeing of the kidney

1. Division of anterior peritoneal attachments
2. Posterior surface of left kidney
3. Psoas major muscle
4. Parietal peritoneum
The kidney is freed from its remaining anterior peritoneal attachments to allow for complete mobilization.

• Ureter

1. Freeing of left ureter
2. Posterior surface of left kidney
3. Psoas major muscle
4. Parietal peritoneum
5. Division of ureter
The ureter is followed and freed as distal as possible. It is then divided after performing ligation with absorbable suture.

9. Extraction

The 10 mm laparoscope is replaced by a 5 mm laparoscope, which is introduced through the posterior trocar. The retroperitoneal space is washed with lukewarm saline. Before extracting the operative specimen, a small caliber drain (eg, Redon CH8) can be placed through the anterior trocar.
We use a retrieval bag introduced through the trocar at the tip of the 12th rib. The operative specimen, which is small in children, can usually be extracted without having to enlarge the initial incision.

10. Postop period

Food intake may be resumed on POD1.
The need for analgesics (continual administration of morphine IV during the first 12 hours, replaced by continual administration of nalbuphine IV, which is stopped at the patient’s request) is usually of short duration in children, rarely lasting more than 36 hours.
The drain and IV are usually removed on POD2.
The patient leaves the hospital on POD2 or POD3 and can resume normal activities a week after discharge.

Specific complications are rare:
- bleeding due to ligature failure on a renal pedicle is a theoretical risk whose occurrence is exceptional;
- a hematoma or wound infection is always possible;
- a urinoma can occur in the retroperitoneal space in cases of vesicoureteral reflux if no ureteral ligature was performed (or if the ligature fails).

Published studies (El Ghoneimi, 1998; Shanberg et al., 2001) all underline the feasibility of nephrectomies by retroperitoneoscopy in children and infants, as well as a very low complication rate.

11. Reference

Clayman RV, Kavoussi LR, Soper NJ, Dierks SM, Meretyk S, Darcy MD et al. Laparoscopic nephrectomy:
initial case report. J Urol 1991;146:278-82.
El-Ghoneimi A, Valla JS, Steyaert H, Aigrain Y. Laparoscopic renal surgery via a retroperitoneal approach
in children. J Urol 1998;160:1138-41.
Gaur DD. Retroperitoneal surgery of the kidney, ureter and adrenal gland. Endosc Surg Allied Technol
1995;3:3-8.
Gaur DD, Agarwal DK, Purohit KC. Retroperitoneal laparoscopic nephrectomy: initial case report. J Urol
1993;149:103-5.
Peters CA. Laparoendoscopic renal surgery in children. J Endourol 2000;14:841-7; discussion 847-8.
Shanberg AM, Sanderson K, Rajpoot D, Duel B. Laparoscopic retroperitoneal renal and adrenal surgery in
children. BJU Int 2001;87:521-4.
Yao D, Poppas DP. A clinical series of laparoscopic nephrectomy, nephroureterectomy and
heminephroureterectomy in the pediatric population. J Urol 2000;163:1531-5.

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