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The Laterally Extended Parametrectomy
(LEP)
108
László Pálfalvi, MD, PhD
László Ungár, MD, PhD, MHCOG
is the mid part of the pelvic side wall, corresponding to
the lateral insertion of the parametrium, exactly where the
gluteal superior, inferior and pudendal lymph nodes are
located. Incomplete resection of this region is a limitation
of the classical Wertheim procedure.
2. The aim of the radical hysterectomy is not only the
removal of the central cervical tumour with adequate free
margin, but the removal of preferably all pelvic ways of
tumour spreading. Several studies have documented the
location of parametrial positive lymph nodes, and found
them randomly distributed, with an almost equal number
of metastatic parametrial lymph nodes in the medial and
lateral parametria (2,3).
3. Reiffenstuhl in his classic study of the lymphatics of
the female genital organs, describes efferent lymph
channels from the cervix to the superior and inferior
gluteal nodes (4). These nodes also represent primary
lymph nodes draining the cervix. The classical class IIIIV radical hysterectomy does not remove the connective
tissue situated lateral to the hypogastric vessels, that
contains these nodes. Admittedly, this is a week point
in the performance of pelvic lymphadenectomy and in
attempting to remove all nodes that represent primary
station to which cancer from the cervix may metastasize.
Surgical Technique.
Introduction
The laterally extended parametrectomy (LEP) is a new radical
technique for pelvic side wall dissection in cervical cancer
operations.
Since Ernst Wertheim and Friderich Shauta, there
has been a continuous debate amongst gynaecological
oncologists about the role and correct extent of pelvic
parametrectomy and lymphadenectomy. For the past century
the Wertheim radical hysterectomy has been the gold
standard for the surgical treatment of cervical cancer.
Local control remained a problem, however, as most
tumour recurrences occurred in the pelvis with most patients
dying from local recurrence. Thus, it is evident that improving
local control in the treatment of cervical cancer could also
improve survival. In 1993 we introduced a more extensive
surgical technique at St. Stephen’s Hospital Budapest for the
treatment of lymph node positive stage Ib cervical cancers
and all cancers of stage IIb. The intervention, which we call
“Laterally Extended Parametrectomy” (LEP), is aimed at
removing all the lymphatic tissue from the pelvic side wall.
This procedure removes parametrial tissue not removed by a
conventional class III-IV Wertheim hysterectomy by extending
the lateral limits of the dissection to the true boundaries of the
pelvic side wall, rather than the medial surface of the internal
iliac vessels.
The dissection of the pelvic side wall begins with a
meticulous pelvic lymphadenectomy. The external iliac,
common iliac, obturator and presacral nodes are dissected.
In order to remove all lymphatic fatty tissue surrounding the
vessels, we mobilise the iliac vessels from the psoas muscle,
displacing them medially, preserving the genitofemural nerve.
Connective tissue between the vessels is dissected, so that
the entire circumference of the external and common iliac
arteries and veins are free. As the vessels are retracted from
the psoas muscle, (a small vascular branch from the iliac
vessels to the muscle is usually divided here), the lateral
or “deep” common iliac nodes can be dissected. In fact the
nodes include the gluteal superior and iliolumbar nodes.
There is no well defined limit between the “lateral common
iliac” nodes and the cranial part of the obturator nodes. In
this way the fatty tissue between the common iliac vein and
the sacrum can also be removed. This part of the pelvic fatty
Theoretical Considerations
The LEP procedure is based on three theoretical
considerations; namely that most of the treatment failures
in cervical cancer are due to pelvic side wall recurrences,
that lymph node metastases can be located anywhere in the
parametrium or pelvic side wall lymph nodes, and that the
connective tissue containing lymph nodes situated laterally
to the internal iliac vessels was considered technically
inaccessible in most of gynaeco-oncological centres.
1. In most cervical cancer patients who experience relapse,
recurrence is located in the small pelvis, with most of these
occurring on the pelvic side wall. Höckel showed that
approximately 80% of the pelvic side wall recurrences are
situated in the “infrailiac - acetabular” region, based on a
study of autopsy data from 138 patients (1). This region
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The Laterally Extended Parametrectomy (LEP) u
Figure 1. Dividing the parietal branches of the hypogastric vessels:
(1) The obturator vessels. (2) The external iliac vessels. (3) The
obturator nerve. (4) The ureter. (5) The gluteal superior vessels, (6)
The hypogastric vessels. (7) The gluteal inferior vessels.
tissue is a bridge between the “deep” or lateral common
iliac nodes and the presacral nodes. Without discussing the
anatomical terminology of the different lymph node stations,
the pelvic lymphadenectomy is complete when the vessels
are totally free all around their circumference, the obturator
nerve is visualised posterior until its retro-psoas portion, and
the fatty tissue around the obturator nerve has been removed
such that the superior branch of the sacral plexus is visible.
The essence of the laterally extended parametrectomy
(LEP) is using a different dissection plane than in the
conventional radical hysterectomy. Not the visceral branches
of the internal iliac vessels are sectioned, but the parietal
branches are clipped and divided at the point where they
leave or enter the pelvis (Figure 1).
Thus the entire hypogastric system is removed, and no
connective tissue is left on the pelvic side wall. The technique
is the following: after completing the lymphadenectomy,
we clip and divide the iliolumbar, and the gluteal superior
vessels, and dissect free the superior branch of the sacral
plexus. Anterior, the obturator vessels are also ligated and
divided on the surface of the obturator internus muscle.
We ligate and divide the internal iliac artery and vein. With
slight medial traction on the dissected internal iliac vessels,
the sacral plexus with the piriformis muscle between and
under its branches can be dissected free, using hemoclips
for the variable number of parietal vessels of this region.
Finally, we clip and divide the pudendal and gluteal inferior
vessels at their entrance/exit from the pelvis. At the end of
this procedure, the following structures of the pelvic wall
can be seen clearly from antero-inferior to postero-superior
direction, with no connective tissue intervening: the levator
ani and the internal obturator muscles, the linea arcuata,
above it the psoas muscle, under it the piriformis muscle with
645
Figure 2. The “true” pelvic side wall: (1) Gluteal superior artery. (2)
Ligated hypogastric vessels. (3) Branches of the sacral plexus. (4)
Ureter. (5) The hypogastric vessels. (6) Pudendal artery. (7) Arcus
tendineus. (8) Linea arcuata. (9) Obturator nerve.
the convergent branches of the sacral plexus, posterior the
sacrum (Figure 2).
The main technical difficulty of the procedure results from
the variable number and calibre of the pelvic side wall veins.
Heavy bleeding may occur and electrocautery can not be
used because of the nervous plexus. Suture ligation or the
application of hemoclips to bleeding vessels may be required
for haemostasis. In one case we had to pack the small pelvis
in order to stop bleeding. The gauze packing was removed on
the 4th post operative day. The patient recovered without any
further complications.
Discussion
The aim of surgical treatment of cervical cancer in patients
in whom tumour has spread beyond the cervix is to resect all
the connective tissue of the pelvis, (“pelvic fascia”, or “corpus
intrapelvinum”, as named by Hafferl cited by Burghardt)
(7). The standard class III- IV technique, which dissects the
parametrium step by step and divides the parametrial vessels
at their origin from the internal iliac vessels can remove most
of the parametrium, but not all of the connective and lymphatic
tissue of the pelvic side wall. The internal iliac vein which
remains does not represent the “pelvic wall” as maintained
in most of the publications. The true pelvic side wall in this
region is represented by the linea arcuata, the piriformis
muscle and the large branches of the sacral plexus, lying
on the piriformis muscle. When all of these structures are
dissected free of lymphatic tissue, we consider the resection
of the parametrium to be “complete”. All of our cases also
included thorough paraaortic lymphadenectomy.
The LEP procedure can be performed unilaterally or
bilaterally, depending on the presence of tumour positive
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u The Laterally Extended Parametrectomy (LEP)
lymph nodes, or parametrial infiltration on the side in question.
A class II-IV Wertheim hysterectomy is performed in the case
of stage Ib tumours on the side with negative lymph nodes
on intraoperative histology, or the side with no parametrial
infiltration in case of IIb patients. Bilateral LEP procedures
were done in 15 cases and no complication arose from the
ligation of both hypogastric arteries. In two cases of bilaterally
performed LEP, the inferior mesenteric artery was also ligated
during the paraaortic lymphadenectomy but no complications
occurred, although the blood supply of the entire left colon
was dependent upon the marginal artery.
As practically no connective tissue remains on the pelvic
side wall after the LEP procedure we did not measure the
length of the parametrium removed or the number of pelvic
lymph nodes as recommended by Benedetti-Panici (8). The
number of nodes counted depends also on the “radicality” of
the pathologist, and the parametrium, extirpated “en block”
with the entire hypogastric system can not be compared to
the conventional techniques as its “length” measured in vitro
is unrealisticly long.
In lymph node positive or in stage IIb cases, the long-term
disease free survival seems to be better than that obtained
with conventional surgery plus irradiation or irradiation alone
(9). Our 15 years of experience with this technique have
established the feasibility of the method with an acceptable
complication rate. The amount of blood loss is higher than
in the conventional radical hysterectomy, but decreases
substantially with increased experience of the surgeon.
References
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