Pre-operative Computed Tomographic(CT) Scan Templating in Adolescent Idiopathic Scoliosis(AIS): Is it Really Necessary

Transcription

1 Pre-operative Computed Tomographic(CT) Scan Templating in Adolescent Idiopathic Scoliosis(AIS): Is it Really Necessary Mark BH TAN Senior Resident, Department of Orthopaedic Surgery, TTSH Reuben CC SOH Consultant, Department of Orthopaedic Surgery, KKH Visiting Consultant, Spine Service, Department of Orthopaedic Surgery, SGH, TTSH Adj Asst Prof, Duke-NUS Graduate Medical School 1

2 Background Current Utilization of Prone CT scans in Pre-operative Planning for Spinal Fusion in AIS Pedicle Morphology: Height, Length, Width Rotation of Vertebral Body Cephalo-caudal Pedicle Trajectory Routine use of CT scans raises concerns regarding the high dose of ionizing radiation in the developing child 2

3 Aims Compare Pedicle Width, Height and Length Measurements on Plain Radiographs to the same Parameters evaluated on CT scans Determine if CT scans can add more information to Pre-operative planning in routine AIS cases 3

4 Inclusion Criteria AIS Patients who underwent Spinal Fusion between 2012 and 2014 in KK Women s and Children s Hospital Pre-operative Standing PA, Lateral and Side Bending Radiographs Pre-operative CT scans for Surgical Planning 4

5 Methodology Under the Study Protocol, 2 Surgical Residents and 1 Senior Surgeon reviewed all radiographs and CT scans of 54 Patients T12 and L1 Vertebrae were used as surrogates for comparison for pedicle height, width and length Largest T12 and L1 vertebrae heights and widths measured on Standing PA and Lateral Bending Radiographs used for comparison to parameters measured on CT scan L1 Pedicle Length measured on Lateral Radiographs compared to dimensions determined by CT scan 5

6 Standing and Lateral Bending Films Largest Visible T12 and L1 Pedicles Used for Measurements E.g. Left Bending Film used for the below Measurement 6

7 Parameters Measured on XR and CT Example (Same Patient) Plain XR L1 Vertebrae Height: 14.26mm Width: 4.98mm Length: 48.50mm CT Scan L1 Vertebrae Height: 14.05mm Width: 4.96mm Length: 48.38mm 7

8 Results Retrospective Review of 54 Patients with an average Cobb angle of 61.5 ( ) Pedicle Height and Width on Plain Radiographs of the T12 vertebrae showed good correlation with dimensions measured on CT scan (p<0.001) T12 Pedicle Width showed Mean Difference of 0.57mm T12 Pedicle Height showed Mean Difference of 3.11mm T12 Pedicle Width Measured on XR compared to CT scan Bland- Altman Plot of T12 Pedicle Width Difference : Average T12 Pedicle Width Measured on XR Difference on XR compared to CT T12 Pedicle Width Measured on CT Average T12 Pedicle Height Measured on XR compared to CT scan Bland- Altman Plot of T12 Pedicle Height Difference : Average T12 Pedicle Height Measured on XR Difference on XR compared to CT T12 Pedicle Height Measured on CT Average 8

9 Results Pedicle Height and Width Measurements on Plain Radiographs of the L1 vertebrae showed good correlation with dimensions measured on CT scans (p<0.001) L1 Pedicle Width showed Mean Difference of 0.38mm L1 Pedicle Height showed Mean Difference of 2.89mm L1 Pedicle Width Measured on XR compared to CT scan Bland- Altman Plot of L1 Pedicle Width Difference : Average L1 Pedicle Width Measured on XR Difference on XR compared to CT L1Pedicle Width Measured on CT Average L1 Pedicle Height Measured on XR compared to CT scan Bland- Altman Plot of L1 Pedicle Height Difference : Average L1 Pedicle Height Measured on XR Difference on XR compared to CT L1Pedicle Height Measured on CT Average 9

10 Results L1 Pedicle Length showed Mean Difference of 5.50mm L1 Pedicle Length Measured on XR compared to CT scan Bland- Altman Plot of L1 Pedicle Length Difference : Average L1 Pedicle Length Measured on XR Difference on XR compared to CT L1Pedicle Length Measured on CT Average 10

11 Conclusion Study supports the use of pre-operative plain radiographs to obtain measurements in the estimation of pedicle screw size and insertion Given the distinct disadvantage of Ionizing Radiation and Cost, it is reasonable to avoid routine CT imaging of the spine in AIS patients planned for spinal fusion 11

12 Disclosure Declaration The authors declare that there are no potential conflicts of interest The authors are the current copyright hold of the E- poster presentation created and hereby license the work to EUROSPINE, the Spine Society of Europe according to the Eurospine License Agreement 12