whereas the position of the distal preaortic portion of the vein hardly changed because of the mesenteric a. and reno-
hemi -azygo-lumbar trunk linking it to the posterior abdominal wall. The viewing axis was orientated toward the reno-
hemi -azygo-lumbar trunk (Fig. 3 ), which could easily be confused with the distal renal v., as it continued in this position
in the same direction as the proximal portion of the vein. The renal a. could also be partly hidden by the reno-hemi-
azygo-lumbar trunk as it passed beneath it. If the latter was confused with the renal v. the unusual aspect of a pre -venous
artery may have been seen (Fig. 3b). A reno-hemi -azygo-lumbar trunk was found in all but one of the five dissections in
which case the left renal v. had a retroaortic position and no parietal tributary.
The termination of the left gonadal v. into the renal vein was a valuable marker for locating the suprarenal v., which
joined the renal v. superomedially. Owing to the inferior approach to the pedicle the suprarenal v. was only visible after
ligation or upward retraction of the renal a. The most appropriate way of approaching the left suprarenal v., as in
adrenalectomy, was to separate the renal a. and v. and follow the upper brim of the renal v. medially to the termination of
the left gonadal v.
On the right the inferior vena cava was easily identifiable on the medial edge of psoas major after opening Gerota's
fascia. Gradual dissection of the inferior vena cava from inferior to superior revealed successively, as during
lumboscopy, the gonadal, renal and suprarenal vv., which were all located in the same plane. No reno-azygo-lumbar
trunk was found on the right side. Because of its retrocaval position the renal a. appeared to wind around the inferior vena
cava when the kidney was mobilized ventrally (Fig. 2b).
Discussion
Compared with open surgery laparoscopic surgery is associated with lower operative blood loss, reduction in
postoperative analgesia requirements and a shortened hospital stay [1, 2, 8]. The laparoscopic approach to the
retroperitoneum can be achieved by the retroperitoneal route (lumboscopy) or by the transperitoneal route the choice
between the two techniques depending on the condition and the surgeon's experience. Studies comparing these two
approaches have shown that lumboscopy reduces the time taken to resume normal oral intake and postoperative analgesia
requirements. However, transperitoneal laparoscopy and lumboscopy have similar results in terms of complication rates
and length of hospital stay [8, 14, 18].
The view of the retroperitoneum provided by the transperitoneal route is similar to that of open surgery because
intraperitoneal insufflation does not modify the position of the retroperitoneal organs. During lumboscopy the approach
to the renal compartment necessitates insufflation of the posterior pararenal space, which modifies the position of kidney
and its pedicle as well as changing the anatomical landmarks.
Anatomical landmarks of lumboscopy
Digital dissection of the posterior pararenal space permits palpation of psoas major and the posterior aspect of the kidney,
as well as beginning lateral detachment of the renal compartment with the assurance that one is in the correct cleavage
plane. The digital approach behind the posterior axillary line avoids damaging the peritoneum, the reflection of which is
always located more anteriorly [7].
Several techniques have been described to detach the posterior pararenal space, the principal ones being digital dissection
and balloon dissection [3, 10 , 11 , 15 , 20 ]. Balloon dissection, introduced by Gaur [11], is widely used, but it does not
appreciate the medial limit for detachment between the parietal fascia and the posterior layer of the renal fascia, the
fusion of which can occur at various levels between quadratus lumborum and psoas major [16, 17, 19]. Moreover, poor
placement of the balloon can lead to rupture or tissue damage [11, 20].
Outside the kidney, the lateroconal fascia separates the posterior and anterior pararenal spaces and thus protects the
retroperitoneal digestive organs (duodenum, pancreas and colon). During insufflation of the posterior pararenal space, the
lateroconal fascia is condensed and insinuates itself into the space between the kidney posteriorly and the colon anteriorly
[15 ]. In radical nephrectomy this fascia has to be collapsed in order to approach the anterior pararenal space, but owing to
its thinness there is considerable risk of entering the peritoneal cavity, especially in the abdominal midline where the
plane of dissection is the least apparent [24]. Meticulous dissection of the peritoneum is required to remain within the
anterior pararenal space, however it may be preferable to enter the perirenal space to avoid laceration of the digestive
tract.
A key safety measure is to avoid dissecting the area of the retroperitoneal vessels until psoas major has been accurately
identified. During initial digital dissection its palpation provides the medial limit of blunt dissection. After introduction of
different trocars psoas major must be visualized as laterally it limits the area of the retroperitoneal vessels. On the left the
renal pedicle can be approached by opening Gerota's fascia anterior to psoas major. On the right the inferior vena cava is
usually readily identified at the medial edge of psoas major progressive upward dissection enables the successful
identification of the gonadal v., renal pedicle and the suprarenal v.
Description of the renal pedicle in lumboscopy