technique of percutaneous iliosacral screw fixation of sacroiliac disruptions with the patient in su

TECHNIQUE OF PERCUTANEOUS ILIOSACRAL SCREW FIXATION OF

SACROILIAC DISRUPTIONS WITH THE PATIENT IN SUPINE POSITION

Dr. Libin Thomas ManatharaKOACON Regn. no. 50083

Dr. Libin Thomas Manathara, KOACON 2016 Regn. No. 50083

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CASE PRESENTATION• 39yr old female nurse involved

in a road traffic accident complaining of severe lower back pain and inability to move the right hip

• Initial radiogrpahs revealed a right sacroiliac joint disruption and right inferior pubic ramus fracture. A CT taken confirmed the same. A 3D reconstruction image is displayed

• After pre op evaluation she was planned for a right percutaneous sacroiliac screw fixation using a modification of the Routt et al technique with patient in supine position


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• It is important to note that the normal sacral ala has an inclined anterosuperior surface, the sacral alar slope, that extends from proximal-posterior to distal-anterior

• It is because of this slope that we use 3 different AP views to confirm our guide wire is in the right place

• Anterior to the sacral ala in this region run the L5 nerve root and the iliac vessels

• The cortex of the alar slope forms the anterior boundary of the “ safe zone ” for passage of iliosacral screws into the body of S1

• The posterior boundary of the safe zone is formed by the foramen of the S1 nerve root

• The sacral alar slope can be estimated on a true lateral fluoroscopic view of the sacrum by identifying the iliac cortical density (ICD), which demarcates the anterior cortical thickening of the iliac portion of the sacroiliac joint

THE ANATOMY OF THE SACRAL ALA


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With the patient in supine position, the landmarks iliac crest and greater trochanter were marked and a C- arm was used to identify the entry port. The entry port would be created with a vertical arm and an intersecting horizontal arm. A K wire was used to aid us in this process. Here you can see the K wire being placed over the hip to mark the vertical arm


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Marking the vertical arm of the entry point

• The C arm images showing the K wire in the right place in a true AP and a 40 degree caudal view are displayed

• Our marking on the patient is also shown, both lines would intersect at a point on the lateral aspect of pelvis marking the vertical arm of the entry point


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Varying views to identify the vertical arm of the entry point

• The anteroposterior view, 40 degrees cephalad and 40 degrees caudal views were used to ascertain that the vertical arm remains in the sacral promontory

• This is due to the sacral alar slope as described earlier


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Marking the horizontal arm of the entry point

• This is done using a K wire as shown previously, the mark is kept in the safe zone, as described earlier, just behind the iliac cortical density (ICD) and in front of the foramina of the S1 nerve root


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The guide wire is advanced and its position too is confirmed in the manner used previously. A 6.5 by 110mm cannulated partially threaded cancellous screw with a washer was also advanced after drilling over the guide wire and taking appropriate measurements


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Intra operative C arm images of the screw in place

• The image on the left shows the screw in the safe zone of the sacral ala just behind the iliac cortical density (ICD)

• Anteroposterior view is also seen, the washer is also clearly visible


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Immediate post operative x ray shows a satisfactory placement of the screw in anteroposterior view


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35th post operative day follow up

• The patient was seen on the 35th post op day and she has a significant decrease in pain

• The early follow up X rays show good reduction with proper screw placement

• The patient was allowed weight bearing 3 months after the date of surgery

technique of percutaneous iliosacral screw fixation of sacroiliac disruptions with the patient in su

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