Anterolateral Retroperitoneal Incision 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
 www.vumc.org/global-surgical-atlas  
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
Introduction 
Accessing the retroperitoneal space with a 
peritoneum-sparing incision through the lateral 
abdominal wall muscles can make exposure much 
easier than a trans- peritoneal approach. The intra-
abdominal contents are held back by the peritoneum 
itself, so retraction is much simpler. This is the 
approach of choice for open access to mid-ureteric 
stones, psoas abscesses, the iliac vessels or even (in 
experienced hands) the infrarenal aorta. Another 
well-described use of this approach is an incision 
above the inguinal ligament, accessing the external 
iliac artery without entering the abdominal cavity, to 
gain proximal control of a femoral artery injury in the 
groin. This incision is also used for kidney 
transplant;  the kidney is placed in the lateral 
retroperitoneal / retropelvic space after the renal 
vessels are anastomosed to the iliac artery and vein, 
and the ureter is implanted into the bladder. This 
approach is sometimes called the Gibson incision.  
This approach makes use of the fact that there 
is a distinct and non-adherent plane between the 
peritoneum and the internal oblique muscle. This 
plane can often be developed even in the presence of 
inflammation; the peritoneum is surprisingly tough. 
The key to this approach is to keep in mind the layers 
of the lateral abdominal wall and to be aware of 
which one is being divided or retracted.  
 
Cross section of the right abdomen just above the anterior 
superior iliac spine shows the path of dissection after division 
of the three layers of the lateral abdominal wall. The Red line 
follows dissection through the extraperitoneal fat below the 
transversus abdominis muscle (Red dot) until the peritoneum is 
reached. This is then retracted medially off the psoas muscle 
(Blue dot) allowing dissection of the plane between the 
peritoneum and the psoas muscle all the way to the vertebral 
body. The iliacus muscle (Green dot) will be at the floor of the 
dissection and may be seen as well. Source: National Library 
of 
Medicine 
Visual 
Human 
Project 
https://www.nlm.nih.gov/research/visible/visible_human.html  
 
It is best to avoid entering into the inguinal 
canal, so the lowest this incision should be made is 
about 4cm above the inguinal fold. It is possible to 
reach deep into the pelvis including structures such 
as the psoas muscle, iliac arteries, bladder, and distal 
ureter with this incision. 
Psoas abscesses will sometimes present with 
a fluctuant mass just medial to the anterior superior 
iliac spine. These are easily drained with a small skin 
incision. In effect, as the abscess expanded it 
followed in reverse the sequence of dissection 
described here, moving through the retroperitoneal 
plane and then the lateral abdominal wall muscles 
until it reached the skin.  
The incision proceeds in the following steps:  
● Transverse or oblique incision lateral to the 
rectus abdominis muscle 
● Sharp 
division 
of 
the 
external 
oblique 
aponeurosis 
● Blunt or electrocautery division of the internal 
oblique and transversus abdominis muscles, 
taking care not to enter the peritoneum. 
● Dissection of the peritoneum off of the 
transversus abdominis muscle proceeding in a 
medial, then posterior direction until the 
pathology is reached.  
● Blunt dissection with retraction, within the 
retroperitoneum to further expose the area to be 
operated.  
 
Steps:  
1. Decide the location of the incision, based on 
imaging. A CT scan is best for this: by carefully 
examining the axial and coronal images, the 
location of the incision can be chosen based on 
external landmarks such as the anterior superior 
iliac spine. Alternatively, an abdominal x-ray 
Anterolateral Retroperitoneal Incision 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
 www.vumc.org/global-surgical-atlas  
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
that shows the location of the pathology can help 
you visualize its precise level.  
 
One 
example of a patient who would benefit from this incision. This 
intravenous pyelogram shows a stone impacted where the ureter 
crosses over the pelvic rim (Blue arrow.) To access this location, 
make an incision adjacent to the upper anterior superior iliac spine 
(Blue dot,) a palpable landmark. Case courtesy of Dr Aditya Shetty. 
From the case https://radiopaedia.org/cases/27748?lang=us  
 
 
Incision location for open ureterolithotomy in the patient above. The 
anterior superior iliac spine (Red Dot) is a palpable landmark that 
is also visible on x-ray. The incision is placed within Langer’s lines 
for cosmesis. (For further information about ureteral stone disease 
see the Section on Urinary Tract Stones.)  
 
 
Non-contrast CT in a patient with right sided abdominal pain shows 
an air and fluid collection (Red dot) below the internal oblique 
muscle, likely in the retroperitoneal space and displacing the 
peritoneum medially. 
 
 
For the patient above, a flank incision was planned around the level 
of the umbilicus.  
 
Anterolateral Retroperitoneal Incision 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
 www.vumc.org/global-surgical-atlas  
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
2. After skin incision, with proper retraction, divide 
the external oblique aponeurosis. If the incision 
is at or below the anterior superior iliac spine, 
you may see the iliohypogastric   and ilioinguinal 
nerves (the iliohypogastric is more cranial.) Take 
care to avoid injury to this structure. If the 
incision is not located near the inguinal canal, 
such precautions are not necessary as there are no 
nerves running deep to the external oblique 
aponeurosis. 
 
After skin incision, the subcutaneous fat including Scarpa’s fascia 
is divided and the external oblique aponeurosis is cleared. As the 
inguinal canal is nearby, the aponeurosis should be divided sharply 
with scalpel and scissors, to avoid injury to the ilioinguinal or 
iliohypogastric nerves. The anterior superior iliac spine is indicated 
by the Red dot. The inguinal fold is indicated by the Red line. 
 
After sharp division of the external oblique aponeurosis, the internal 
oblique muscle, coursing from inferolateral to superomedial, is 
visible. The iliohypogastric nerve, covered by fibrous tissue, is 
visible (Blue arrow.) Injury to this structure should be avoided, both 
at this stage and later on in the operation.  
 
3. Identify and separate, either bluntly or with 
diathermy if necessary, the fibers of the internal 
oblique muscle. Frequently reposition the 
retractors to keep the structures clear. Careful 
retraction, hemostasis, and attention to detail 
allow the surgeon to recognize each muscle layer 
based on their orientation: The internal oblique 
muscle 
fibers 
run 
from 
inferolateral 
to 
superomedial. 
The 
transversus 
abdominis 
muscles run straight transverse from medial to 
lateral. (This anatomy is reviewed in the chapter 
Approach to Abdominal Incisions.)  
Anterolateral Retroperitoneal Incision 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
 www.vumc.org/global-surgical-atlas  
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
The internal oblique fibers have been bluntly separated, with 
the iliohypogastric nerve (Blue arrow) being swept downwards. 
The transversely oriented fibers of the transversus abdominis 
muscle is visible at the base of the wound.  The internal oblique 
muscle should be further separated laterally, either bluntly or 
with electrocautery, but care must be taken to avoid injury to 
the nerve.  
 
 
For the second patient described in Step 1, the external oblique 
aponeurosis (Green dots) and the internal oblique muscle (Blue 
dots) have been divided, revealing the transversely oriented 
fibers of the transversus abdominis (Black dot.)  
 
4. Insert a clamp between the fibers of the 
transversus abdominis and gently dissect the 
space posterior to it. If you can separate them 
bluntly, do so. Otherwise, elevate the fibers so an 
assistant can divide them by diathermy. At this 
point the pre-peritoneal fat and possibly the 
peritoneum can be seen; elevate the muscle away 
from these structures so they are not injured 
while dividing the muscle. Continue the 
dissection until the transversus abdominis has 
been divided or separated for the whole length of 
the incision. If using diathermy, be mindful of 
any nerves you have previously seen and 
retracted.  
 
The transversus abdominis muscle has been separated bluntly 
and the fat in the preperitoneal space is visible. Dissection will 
now proceed bluntly, between the fat and the transversus 
abdominis muscle, proceeding in the plane and direction shown 
by the green arrow.  
 
5. Bluntly dissect the peritoneum off of the 
transversus abdominis laterally and posteriorly, 
entering the retroperitoneal space. If necessary, 
divide or separate the internal oblique and 
transversus abdominis muscles until they are 
separated for the entire length of the incision. A 
narrow malleable or narrow Deaver retractor can 
be helpful with this dissection. If you are at or 
below the level of the anterior superior iliac 
spine, you will be dissecting medially and 
posteriorly along the iliacus muscle. If you are 
above the level of the iliac wing, you will be 
dissecting along the medial aspect of the 
transversus abdominis. 
Anterolateral Retroperitoneal Incision 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
 www.vumc.org/global-surgical-atlas  
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
Incision for the second patient discussed in Step 1. After the 
transversus abdominis muscle was divided, the abscess cavity 
was encountered immediately below this structure. The Green 
dot represents the peritoneum, thickened from inflammation, 
displaced medially by the purulent fluid, which has been 
evacuated.  
 
6. For a psoas abscess or other retroperitoneal 
abscess, dissection in this area may be difficult. 
For other conditions such as approach to the 
ureter or vascular access, it is easy to bluntly 
dissect within the retroperitoneum with proper 
retraction and illumination. There may be a small 
amount of inflammation around a ureteric stone, 
this will signal that you have reached the correct 
location.  
 
Blunt dissection in the extraperitoneal plane towards the psoas 
muscle becomes increasingly more difficult until the psoas is 
reached. Sometimes the psoas muscle can be bluntly dissected 
off the peritoneum. At other times the abscess ruptures into the 
surgical field, as above. In either case, the abscess cavity can 
be entered bluntly with a fingertip and then irrigated.  
 
 
Left sided extraperitoneal exploration after iatrogenic ureteral 
injury. The bladder (opened)  and the course of the left ureter 
are exposed through this incision. The retractor shown by the 
Red dot retracts the peritoneum superomedially. Source: 
Shekar, P.A., Kochhar, G., Reddy, D. et al. Management of 
ureteric avulsion during ureteroscopy: a systematic review and 
our 
experience. 
Afr 
J 
Urol 
26, 
58 
(2020).  
https://doi.org/10.1186/s12301-020-00078-x  
Anterolateral Retroperitoneal Incision 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
 www.vumc.org/global-surgical-atlas  
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
7. Place a drain if indicated. A Penrose drain (or 
cut part of a sterile glove) can be brought out 
through the lateral aspect of the incision and 
sutured to the skin. A closed suction drain can 
be brought out through a separate stab 
incision.  
8. Close the external oblique aponeurosis with 
absorbable suture, taking care not to entrap 
any nerves underneath it. If excessive 
diathermy division of the internal oblique or 
transversus 
abdominis 
muscles 
was 
performed, these can be reapproximated, also 
taking care not to entrap any nerves in the 
closure.  
 
Closure of the external oblique aponeurosis followed by skin 
closure. If a Penrose drain is used, the lateral portion of the 
wound can be left open to allow passage of the drain.  
 
Pitfalls:  
● Placing the incision in the wrong location. If you 
find that you are slightly too high or too low, you 
can increase visibility by extending your incision 
laterally, through the lateral abdominal wall 
muscles, and dissecting the retroperitoneum off 
of the transversus abdominis muscle further.  
● Inadequate hemostasis during the approach will 
make visualization of the tissue planes very 
difficult; take your time and use diathermy, 
suction, and a sponge to keep the plane clean and 
dry.  
● Inadequate lighting will make it difficult to work: 
this approach inevitably creates a deep hole. 
Position the overhead lights before surgery 
keeping in mind where this hole will be. Wear a 
headlight if you have one.  
● Severe inflammation in the retroperitoneum, as 
in a psoas abscess or other perforated viscus or 
tumor, will make this dissection very difficult. 
When draining a psoas abscess by this approach, 
it is rarely possible to dissect around the psoas 
muscle; inevitably the abscess is entered during 
the approach to the muscle. 
● Inadvertent entry into the peritoneal cavity is not 
a problem. A small hole in the peritoneum does 
not need to be closed, either during or at the end 
of the surgery. If the hole is large enough that it 
allows bowel to enter and block your view, close 
the peritoneum with a running absorbable suture.  
 
Richard Davis, MD FACS FCS(ECSA) 
AIC Kijabe Hospital  
Kenya 
 
May 2022 
 
