This article is part of the operation script for grafting an abdominal aortic aneurysm. The article can be used on its own, or to go to the next part of the operation, click on NEXT PART OF THE OPERATION at the bottom of this page.
AORTIC ANEURYSM 230 SECTION 11.00 - OPENING THE ANEURYSM
STEP 11.01 INTRODUCTION
- The aneurysm is opened primarily to gain control of the lumbar arteries.
- The aneurysm may contain thrombus which needs to be removed.
- The surgeon needs to be ready to control bleeding into the aneurysm from vessels probably in the following order:
- Incompletely clamped aorta and iliac arteries.
- Rare sources such as an aorto-caval fistula.
- Lumbar arteries.
STEP 11.02 GO TO THE UPPER END OF THE AORTA
- Use the Deaver retractor to expose the aorta and the upper end of the aneurysm.
STEP 11.03 CHECKS BEFORE OPENING THE ANEURYSM
- Check there is a large bowl available for the blood clot and platelet thrombus from the aneurysm.
- Check the scrub nurse has:
- A 16 FG Foley catheter:
- Balloon checked by inflating to 30ml. with saline.
- Arterial clamp for the distal end of the catheter.
- A 50ml. Luer lock syringe of saline.
- Two spare Foley catheters, in case the balloon on the first one bursts, or the iliac vessels need control with the catheters
- Three stitches of eg 3/0 Vicryl (Ethicon W9136) on the scrub table, one mounted on a long needle holder.
- These stitches will be to underrun any bleeding lumbar arteries in the back wall of the aneurysm.
- There may be as many as six or more.
- They may bleed very near the planned anastomosis at the upper end of the aneurysm.
- Be prepared to underrun the rarer median sacral artery.
- Check the anaesthetist is happy that the patient can stand some blood loss.
STEP 11.04 OPEN THE ANEURYSM LONGITUDINALLY
- Use a scalpel with a No. 15 Swann Morton blade.
- Make a longitudinal incision into the front wall of the aorta.
- Start 5 cm. above the bifurcation.
- Finish 5 cm. below the aortic clamp.
STEP 11.05 REMOVE THE ANEURYSM CONTENTS
- Scoop out blood clots, yellow platelet thrombus and blood with your hand.
- Have a large pack available to pack into the lower part of the aneurysm while you deal with any serious bleeding from above.
STEP 11.06 CONTROL ANY AORTIC BLEEDING
- If there is aortic bleeding:
- The aortic clamp is not tight or not properly positioned.
- Try putting more clicks on the aortic clamp.
- If this controls the bleeding:
- Continue the operation.
- If not:
- Place a second clamp proximal to the first.
- Press the second clamp even more firmly onto the vertebral column than the first, before closing the jaws.
- If the second clamp has controlled the bleeding:
- Remove the first clamp.
- If control is still inadequate:
- Clamp the aorta above the renal arteries and reposition the subrenal clamp.
- If this does not control the bleeding:
- Compress the aorta in the lesser sac with an aorta compressor.
- Insert a Foley catheter 10cm. up the aorta through the aneurysmal incision.
- Inflate the balloon with up to 30ml. of saline to control the bleeding.
- Clip off the filling tube with an artery forcep.
- Make sure the main catheter tube is clamped with the extra arterial clamp.
STEP 11. 07 CONTROL ANY ILIAC ARTERY BACK BLEEDING
- Localise the site of bleeding using swabs, packs and the sucker.
- Tighten the responsible iliac clamp(s).
- Check that they are clamping the common iliac arteries completely.
- Check that they are not just clamping the internal or external iliac arteries only.
- Check that the iliac arteries are not torn.
- If the iliac arteries are torn:
- Double clamp the artery and repair the tear with a continuous suture of eg 4/0 Polypropylene (Ethicon W8935).
- If that does not work:
- Consider tying the iliac arteries off and using a Y graft to the femoral arteries.
STEP 11.08 CLEAN OUT THE ANEURYSM
Remove residual platelet thrombus, blood clot and atheromatous debris.
STEP 11.09 LOOK FOR AN AORTO-CAVAL SHUNT
- This will be on the right hand side of the aorta.
- Stitch the defect in the caval wall with 4/0 Prolene.
- If the caval wall defect is too large for 2-3 free stitches.
- Clamp the defect with a Satinsky clamp to obtain control and then stitch it off.
STEP 11.10 CONTROL LUMBAR ARTERIES
- The lumbar arteries, if not blocked, will be bleeding from the back wall of the aneurysm.
- The vessels are arranged in pairs – up to 6 pairs, corresponding to the vertebrae.
- The aortic clamp may compress the lining of the aorta and hide the uppermost two.
- Complete control of bleeding is essential to prevent blood obscuring the suturing of the anastomoses, as well as causing hypovolaemia.
STEP 11.11 UNDER-RUN ANY LUMBAR ARTERIES
- Excise flaps of atheroma holding the arterial orifices open, before stitching the vessels off.
- Use criss-cross stitches of eg 3/0 Vicryl (Ethicon W1936).
- You should now have a relatively bloodless field inside the aneurysm sac.
- A minute or two spent controlling minor bleeders at this point is well worth the extra effort.
STEP 11.12 EXTEND THE AORTIC INCISION
- Use Metzenbaum scissors.
- Cut the aneurysm wall distally down to 2cm. from the bifurcation of the aorta.
- Remove thrombus from here.
STEP 11.13 INSERT A RETRACTOR INTO THE ANEURYSM
- Use a Travers self-retaining retractor.
- Place the handles distally, so that they do not impede making the upper anastomosis.
- Open the jaws to display the inside of the aneurysm.
- Stitch off any residual lumbar arteries.
STEP 11.14 ANTICOAGULATE THE ILIAC ARTERIES AGAIN
- Use the 20ml. syringe with a blunt bulb adaptor (blob) containing heparin saline.
- Temporarily open the iliac clamps in turn to flush 3 syringefuls of heparin saline down each common iliac artery.
STEP 11.15 PROGRESS SO FAR
- You should now have control of bleeding and a cleaned out aneurysmal sac.
- There is always some seepage of blood from retroperitoneal haematomas.
STEP 11.16 WAIT UNTIL THE ANAESTHETIST HAS CAUGHT UP WITH ANY BLOOD LOSS
STEP 11.17 THE NEXT STEP
- Checking the iliac arteries.
- Read on.
