Morphometric Description of Thoracic Vertebral Pedicles in Adult Malawian Cadavers and Implications for Transpedicular Spine Fixation

Thoracic pedicles are important during the surgical repair of the thoracic spine deformities. Individuals show considerable differences in the asymmetric dimensions of the thoracic pedicles across populations. The purpose of this study was to determine the thoracic pedicle size and angle in adult Malawian cadavers and to suggest the clinical implications associated particularly the transpedicular fixation of spinal deformities. Adult thoracic vertebra from undetermined sex specimens (n=227) from the skeletal collection in the Anatomy Division, Biomedical Sciences Department, College of Medicine, University of Malawi were measured to assess the pedicle width, pedicle height, chord length, transverse diameter, interpedicular distance, transverse and sagittal pedicle angles. The mean pedicle width was 4.71 ± 1.83 mm (left side) and 4.82 ± 1.77 mm (right side) and the mean pedicle height was 12.63 ± 2.61 mm (left side) and 12.60 ± 2.54 mm (right side). The mean transverse pedicle angle was 12.22 ± 2.30 degrees (left side) and 12.46 ± 2.34 degrees (right side). The mean sagittal pedicle angle was 9.24 ± 2.67 degrees (left side) and 9.40 ± 2.76 degrees (right side). The mean interpedicular distance was 16.67 ± 2.23 mm. Our sample population generally showed smaller thoracic pedicle dimensions than those reported in other populations. Prior knowledge of the variations regarding the thoracic pedicle dimensions is vital for the determination of the pedicle screw size and design. Most importantly the information helps surgeons during preoperative planning of the transpedicular thoracic spine fixation and radiological interpretation.