DR. Jamlick Micheni Muthuuri Assessment of Spino-pelvic morphometry, a predictor of lumbosacral instability DR. Jamlick Micheni Muthuuri

organization Objectives Rationale Methodology Data Analysis Results Introduction & Background Objectives Rationale Methodology Data Analysis Results Discussion Conclusion References

Introduction & Background What is spinal Balance? Both Central axis - center of mass of the human body Plumb line – drawn from body of CV7 (anteriorly) to SV1 (posteriorly)

What measurements are taken to determine the spino-pelvic morphology as a measure of spinal balance? Lumbar lordosis Sacral slope Pelvic tilt Pelvic incidence Pelvic overhang

Definitions LL = Lordosis is an increased inward curving of the lumbar spine SS = Orientation of the sacral plate in the horizontal plane PI = Anatomic constant which measures the thickness of the pelvis (distance between the centre of sacrum and the centre of hips in the sagittal plain. PT = Orientation of the pelvis in the sagittal plane, described either as anterior or posterior planes SO = Distance between the centre of the sacrum and the bicoxo-femoral axis in the horizontal plane

Objectives To determine which posture (represented by a morphometric measurement) would predict instability.

MEASUREMENTS Pelvic incidence measured using the Duval-Beaupere method: SS=Sacral Slope, PI=Pelvic Incidence, PT=Pelvic Tilt).

KEY Results Group 1 (study) Instability (L4L5 OR L5S1) Group 2 (Control) NORMAL MRI

Gender distribution Male Female Total % Group 1 24 32 56 45 Group 2 36   Male Female Total % Group 1 24 32 56 45 Group 2 36 68 55 124 100

Summary of distribution according to their age groups

BMI BMI Mean CI SD Group 1 29.2 0.1 4.9 Group 2 28.4 7.3 P VALUE   Mean CI SD P VALUE Group 1 29.2 0.1 4.9 Group 2 28.4 7.3 0.7241

Distribution of the angle of lumbar lordosis   Mean CI SD P VALUE Group 1 36.9 0.2 20.5 Group 2 41.9 0.3 22.4 0.3896

Distribution of the angle of sacral slope   Mean CI SD TTEST Group 1 33.8 0.1 13.2 Group 2 41.3 12.3 0.0232

Distribution of the angle of pelvic tilt   Mean CI SD P VALUE Group 1 24.3 0.2 12.7 Group 2 21.6 15.3 0.45030

Distribution of the angle of pelvic incidence morphological constant   Mean CI SD P VALUE Group 1 66.4 0.1 11.3 Group 2 55.2 11.9 0.00038

Distribution of the sacral overhang (displacement) SARAL OVERHANG   Mean CI SD P VALUE Group 1 45.3 mm 0.3 21.4 Group 2 39.8 mm 26.4 0.3670

Conclusion Sagittal spino-pelvic alignment is measurements are significantly different in chronic LBP There is a pattern of imbalance among those with instability Pelvic incidence is significantly higher in those with instability Positional parameters (LL, SS, and SO) are significantly reduced in those with instability, PT is increased to compensate for reduce SS.

Clinical Application The assessment of sagittal balance: essential in the predication of instability a consideration during planning for spine surgery. A simple discectomy in an instable segment Loss of lordosis in fusion

References Roussouly P, Gollogly S, Berthonnaud E, et al. Classification of the normal variation in the sagittal alignment of the human lumbar spine and pelvis in the standing position. Spine 2005;30:346–53. Berthonnaud E, Dimnet J, Roussouly P, et al. Analysis of the sagittal balance of the spine and pelvis using shape and orientation parameters. J Spinal Disord Tech 2005;18:40–7. Legaye J, Duval-Beaupere G. Sagittal plane alignment of the spine and gravity: a radiological and clinical evaluation. Acta Orthop Belg 2005;71:213–20. Rillardon L, Levassor N, Guigui P, et al. Validation of a tool to measure pelvic and spinal parameters of sagittal balance. Rev Chir Orthop Reparatrice Appar Motil 2003;89:218–27. Jackson RP, Hales C. Congruent spinopelvic alignment on standing lateral radiographs of adult volunteers. Spine 2000;25:2808–15.

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