The Effect of Prolonged Pre-Operative Halo Gravity Traction for Severe Spinal Deformities on the Cervical Spine Radiographs

Abstract

Study design: Retrospective review of consecutive series.

Objective: The study sought to assess the effect of prolonged pre-operative halo gravity traction (HGT) on the c-spine radiographs.

Methods: Data of 37 pediatric and adult patients who underwent ≥ 12wks pre-op HGT prior to definitive spine surgery from 2013-2015 at a single site in West Africa was reviewed. Radiographic assessment of the c-spine including ADI, SVA and C2-C7 Lordosis were done at pre HGT and at 4 weekly intervals. Paired T-Test was performed to evaluate changes in these parameters during HGT.

Results: 37pts, 18/19 (F/M). Average age 18.2yrs. Diagnoses: 22 idiopathic, 6 congenital, 3 Post TB, 2 NM and 4 NF. Average duration of HGT: 125 days. Baseline coronal Cobb:130 deg, corrected 30% in HGT; baseline sagittal Cobb:146 deg, corrected 32% post HGT. Baseline ADI (3.17 ± 0.63 mm) did not change at 4wks (P > 0.05) but reduced at 8wks (2.80 ± 0.56 mm) and 12wks (2.67 ± 0.51 mm) post HGT (P < 0.05). Baseline HGT SVA (20.7 ± 14.98 mm) significantly improved at 4wks (11.55 ± 10.26 mm), 8wks (7.54 ± 6.78 mm) and 12wks (8.88 ± 4.5 mm) (P < 0.05). Baseline C2-C7 lordosis (43 ± 20.1 deg) reduced at 4wks (26 ± 16.37 deg), 8wks (17.8 ± 14.77 deg) and 12wks (16.7 ± 11.33 deg) post HGT (P < 0.05). There was no incidence of atlanto-axial instability on flexion extension radiographs at any interval.

Conclusion: Prolonged HGT, while providing partial correction of severe spine deformities, also appeared to have no adverse effect on atlanto-axial stability or cervical alignment. Therefore, HGT can be safely applied for several weeks in the preoperative management of severe spine deformities in pediatric/adult patients.

Keywords: atlanto-dental interval; cervical spine; halo gravity traction; sagittal; sagittal balance; vertical axis.

Figure 1.

Shows the measurement of Atlanto dental interval (ADI): ADI was measured as the distance between the midpoint of the posterior border of the anterior tubercle of C1 and the anterior margin of the odontoid. ADI was measured as the distance between the 2 lines. The line drawn was kept perpendicular to the posterior border of anterior tubercle of C1.

Figure 2.

Showing the measurement of C2-C7 Sagittal Vertical Axis (SVA). C2-C7 SVA was measured as the horizontal distance between the antero-inferior edges of C2 and C7.

Figure 3.

Showing the measurement of C2-C7 Lordosis using computer assisted digital radiography system. The C2-C7 Cobb angle was measured as the angle subtended between the inferior end plate of C2 and the inferior end plate of C7.