What are the indications for the ilioinguinal approach?

Operative management of acetabular fractures.

The ilioinguinal approach allows for excellent access to the front of the pelvis as well as visualisation of a large area of its internal surface from the sacroiliac joint to the pubic symphysis. It can be used for virtually all fractures of the anterior column and anterior wall. The majority of both column fractures can also be treated with this approach.

Articular reductions are done indirectly. They are based on meticulous restora- tion of extra-articular anatomy, since the joint cannot be directly visualised with this approach. (NB: There is no true internervous plane for this approach – the dis- section consists of lifting off muscular, nervous and vascular structures from the inner wall of the pelvis.)

2. How would you position the patient?

I would position the patient supine on a radiolucent pelvic surgery table. I would place a sandbag under the ipsilateral buttock and insert a urinary catheter to empty the blad- der. I would check that the C-arm image intensifier can be positioned to obtain satisfac- tory obturator and iliac oblique views as well as inlet and outlet views of the pelvis.

3. Describe how you would perform the skin incision.

I would make a curved incision from the iliac crest, starting approximately 5 cm superior to the anterior superior iliac spine (ASIS), extending medially to the pubic symphysis.

4. Describe how you would perform the superficial dissection.

After dissecting down through fat, the aponeurosis of the external oblique muscle is exposed. Caution is required in the lateral portion of the wound as the lateral cutaneous nerve may be encountered due to its variable anatomy. The aponeurosis is divided in the line of its fibres from 1 cm above the superficial inguinal ring to the anterior superior iliac spine to deroof the inguinal canal. This exposes the spermatic cord (in men) or round ligament (in women) which can be mobilised and protected by a sling. The ilioinguinal nerve accompanies the spermatic cord/round ligament in the inguinal canal and this should also be identified and protected.

Medially, I would extend my dissection by dividing the anterior part of the rectus sheath to expose the rectus abdominis muscle.

Laterally, I would incise the periosteum along the iliac crest, releasing the abdom- inal and iliacus muscle insertions from the ilium and I would subperiosteally elevate the iliacus from the internal iliac fossa to the SI joint and pelvic brim (the superior edge of the pelvic inlet). I would then pack the internal iliac fossa for haemostasis.

5. Describe how you would perform the deep dissection.

Deep dissection is performed to allow access and surgery performed through three ‘operative windows’. Not all of these will necessarily be required, so the deep dissec- tion is tailored to the injury pattern. These operative windows are the lateral, middle and medial windows.

Medial Window

I would divide the rectus abdominal muscle transversely 1 cm proximal to its insertion into the symphysis pubis and utilise blunt dissection to develop the plane between the back of the pubic symphysis and the bladder (Cave of Retzius/ retropubic space), followed by protection of the bladder with a malleable retractor.

I would then cut through the fibres of the internal oblique and transversus abdominus muscles that form the posterior wall of the inguinal canal medially.

Caution: The Corona mortis (a retropubic vascular communication between the external iliac and obturator arteries) must be ligated if this anatomical variant is present.

Middle Window

I would divide the transversus abdominus and internal oblique muscles that arise from the lateral half of the inguinal ligament. I would then gently push the peritoneum upwards to reveal the femoral vessels, the femoral nerve and the tendon of iliopsoas, which I would isolate with slings.

The iliopectineal fascia separates the neural and vascular compartments and blocks access to the true pelvis from the internal iliac fossa. The fascia is delineated by careful retraction of the femoral vessels medially and the femoral nerve and iliopsoas laterally. It is then divided distally, under direct visualisa- tion, down to the pubic root. The iliopsoas is then retracted laterally, exposing the fascial attachment to the pelvic brim which can be divided safely.

Once the iliopectineal fascia has been released, the true pelvis can be entered from the internal iliac fossa.

Dissection around the iliac vessels should be minimised. This limits risk of vas- cular injury and also preserves the path of the primary lymphatic trunk to the lower extremity which passes medial to the vein.

Caution:

• The lateral cutaneous nerve of the thigh is usually encountered just deep to the con- joint tendon (of the internal oblique and the transversus abdominis), approximately 1–2 cm medial to the anterior superior iliac spine. This nerve can usually be preserved if it is mobilised as it exits the abdominal wall and enters the fascia of the thigh.
• Inferior epigastric artery crosses the posterior wall of the canal at the medial edge of the deep inguinal ring.

Lateral Window

This is developed by releasing the iliacus muscle from the inner surface of the pelvis as described previously.

Summary                                                                         

Window          Boundaries                      Access to

Lateral  Lateral to the iliopsoas tendon and femoral nerve

Middle  Between the iliopsoas tendon/ femoral nerve laterally and the femoral vessels medially

The entire internal iliac fossa from the SI joint posteriorly to the iliopectineal eminence anteriorly

Pelvic brim, quadrilateral plate, and a portion of the superior ramus

Medial  Medial to the femoral vessels   Superior pubic ramus and pubic