TABLE III.
Pre- and Postoperative Radiographic Measurements of the 5 Patients Who Underwent Application of the Tethering Device*
| Patient and Observation Period | MT Cobb Angle (deg) (% Change from Preop.) | Cobb Angle of Instrumented/Tethered Segments (deg) (% Change from Preop.) | Right Bending Cobb Angle (deg) | PT Cobb Angle (deg) (% Change from Preop.) | Lumbar Cobb Angle (deg) (% Change from Preop.) | Axial Rotation† (deg) |
| Patient 1 (closed TRC) | ||||||
| Preop. | 44.0 | 39.6 | 28.9 | 24.6 | 22.7 | 13.3 |
| 5 wk | 35.2 | 30.5 | 18.5 | 17.6 | ||
| 3 mo | 38.7 | 32.1 | 19.5 | 20.1 | ||
| 6 mo | 34.3 | 28.0 | 19.5 | 18.7 | ||
| 12 mo | 35.3 (19.8%) | 26.5 (33.1%) | 18.2 | 19.3 (21.5%) | 16.9 (25.6%) | 12.4 |
| 18 mo | 35.2 | 27.9 | 19.2 | 18.4 | ||
| 24 mo | 36.4 (17.3%) | 28.3 (28.5%) | 13.9 | 19.4 (21.1%) | 20.9 (7.9%) | 6.6 |
| 30 mo | 32.3 | 24.4 | 20.2 | 15.0 | ||
| 36 mo | 35.1 (20.2%) | 26.1 (34.1%) | 9.3 | 19.7 (19.9%) | 18.5 (18.5%) | 9.6 |
| 42 mo | 35.6 | 26.3 | 21.5 | 17.3 | ||
| 48 mo | 36.0 (18.2%) | 26.4 (33.3%) | 23.5 (4.5%) | 16.1 (29.1%) | ||
| Patient 2 (closed TRC) | ||||||
| Preop. | 43.2 | 43.5 | 30.0 | 19.1 | 31.8 | 10.8 |
| 5 wk | 42.1 | 41.9 | 14.2 | 35.0 | ||
| 3 mo | 40.5 | 39.8 | 11.0 | 33.1 | ||
| 6 mo | 42.9 | 36.7 | 9.9 | 28.6 | ||
| 12 mo | 35.4 (18.1%) | 31.2 (28.3%) | 25.7 | 7.1 (62.8%) | 29.5 (7.2%) | 6.5 |
| 18 mo | 37.6 | 30.9 | 3.2 | 30.4 | ||
| 24 mo | 28.9 (33.1%) | 26.3 (39.5%) | 23.9 | 9.4 (50.8%) | 21.7 (31.8%) | 3.8 |
| 30 mo | 38.9 | 30.5 | 3.2 | 32.3 | ||
| 36 mo | 42.9 (0.7%) | 33.5 (23.0%) | 22.3 | 0.0 (100%) | 32.1 (−0.9%) | 7.2 |
| 42 mo | 47.6 | 37.5 | 1.4 | 36.3 | ||
| 48 mo | 50.6 (−17.1%) | 39.1 (10.1%) | 6.1 (68.1%) | 32.3 (−1.6%) | ||
| 54 mo‡ | 58.0 (−34.3%) | 48.0 (−10.3%) | 5.4 (71.1%) | 43.9 (−38.1%) | ||
| Patient 3 (open TRC) | ||||||
| Preop. | 37.2 | 36.2 | 14.7 | 23.7 | 5.0 | 10.4 |
| 5 wk | 30.7 | 28.8 | 12.4 | 15.4 | ||
| 3 mo | 31.8 | 28.3 | 10.3 | 8.8 | ||
| 6 mo | 27.8 | 24.7 | 17.7 | 14.9 | ||
| 12 mo | 18.7 (49.7%) | 14.3 (60.5%) | 19.8 | 17.3 (27.0%) | 5.4 (−8.0%) | 2.1 |
| 18 mo | 22.0 | 8.5 | 6.5 | −8.7 | ||
| 24 mo | 14.9 (59.9%) | −0.7 (101.9%) | 4.2 | 7.4 (68.8%) | −11.8 (336%) | 6.4 |
| 30 mo | 31.7 | −4.5 | −0.8 | −29.1 | ||
| 36 mo§ | 21.0 (43.5%) | −7.9 (121.8%) | 5.7 | −4.9 (120.7%) | −49 (1,080%) | 5.2 |
| 42 mo | 43.5 | −10.0 | 0.1 | −31.7 | ||
| 48 mo§ | 41.1 (−10.5%) | −3.3 (109.1%) | −2.8 (111.8%) | −31.5 (730%) | ||
| Patient 4 (closed TRC) | ||||||
| Preop. | 37.9 | 36.0 | 25.2 | 15.3 | 24.8 | 10.0 |
| 5 wk | 29.0 | 26.1 | 23.0 | 21.5 | ||
| 3 mo | 31.9 | 28.8 | 15.9 | 22.3 | ||
| 6 mo | 33.1 | 29.9 | 13.2 | 20.0 | ||
| 12 mo | 28.2 (25.6%) | 28.0 (22.2%) | 13.0 | 15.1 (1.3%) | 10.6 (57.2%) | 4.5 |
| 18 mo | 34.1 | 31.0 | 15.1 | 2.5 | ||
| 24 mo | 34.8 (8.2%) | 31.4 (12.8%) | 8.2 | 12.9 (15.7%) | 7.9 (68.1%) | 5.4 |
| 30 mo | 36.2 | 33.9 | 17.9 | 8.5 | ||
| 36 mo | 39.1 (−3.2%) | 35.3 (1.9%) | 11.9 | 17.3 (−13.1%) | 4.1 (83.5%) | 0.5 |
| 42 mo | 38.6 | 35.7 | 22.4 | 11.4 | ||
| 48 mo | 38.1 (−0.5%) | 36.0 (0%) | 27.5 (−79.7%) | 18.7 (24.6%) | ||
| Patient 5 (open TRC) | ||||||
| Preop. | 38.0 | 37.2 | 29.4 | 19.4 | 19.1 | 5.4 |
| 5 wk | 18.2 | 16.5 | 9.2 | 15.5 | ||
| 3 mo | 19.5 | 19.5 | 10.5 | 10.0 | ||
| 6 mo | 16.8 | 16.0 | 8.7 | 11.0 | ||
| 12 mo | 14.2 (62.6%) | 8.3 (77.7%) | 23.7 | 7.1 (63.4%) | 4.9 (74.3%) | 4.3 |
| 18 mo | 10.8 | 4.8 | 5.6 | −2.1 | ||
| 24 mo | 12.0 (68.4%) | −1.7 (104.6%) | 28.0 | 1.0 (94.8%) | −3.4 (117.8%) | 3.2 |
| 30 mo | 0.0 | −1.6 | −5.9 | −8.6 | ||
| 36 mo | −2.8 (107.4%) | −10.0 (126.9%) | 29.3 | −4.3 (122.2%) | −15.2 (179.6%) | 0.0 |
| 42 mo | −15.2 | −15.2 | −4.7 | −20.8 | ||
| 48 mo | −12.4 (132.6%) | −12.4 (133.3%) | −4.6 (123.7%) | −21.9 (214.7%) |
*
Negative Cobb angles indicate reversal of curve, i.e., from right-sided to left-sided curve. MT = main thoracic, PT = proximal thoracic, and TRC = triradiate cartilage.
†
Measured from axial MRI scans of the apical vertebra with reference to the horizon.
‡
Underwent posterior spinal fusion at 55 months for curve progression and distal decompensation.
§
Underwent tether removal at 38 months, for overcorrection and distal decompensation, and posterior spinal fusion at 52 months.