Table 1.
Patient demographics
| Variable | Group A (n=16) | Group B (n=33) | p-value |
|---|---|---|---|
| PJK | Non-PJK | ||
| Sex (male: female) | 2: 14 | 4: 29 | 0.104 |
| Age (mean, years) | 62.5 (56–69) | 61.9 (54–69) | 0.408 |
| Mean follow up period (months) | 47.7±23.4 | 45.6±25.6 | 0.392 |
| BMD (T score) | −2.30±0.85 | −1.01±0.67 | 0.027 |
| C7PL in Pre-Op (mm) | 89.85±51.60 | 58.97±66.98 | 0.111 |
| C7PL in FF (mm) | 71.96±58.04 | 55.83±37.00 | 0.423 |
| UIV distance to C7PL in EP (mm) | 1.9±6.0 | 0.5±3.0 | 0.444 |
| UIV distance to C7PL in FF (mm) | −5.5±5.4 | −2.5±3.4 | 0.019 |
| SS in Pre-OP (°) | 15.38±5.88 | 16.91±6.59 | 0.433 |
| PT in Pre-Op (°) | 42.06±12.00 | 41.21±9.16 | 0.785 |
| PI in Pre-Op (°) | 57.94±12.70 | 58.45±8.37 | 0.865 |
| Anterior-posterior | 6 (37.5) | 16 (48.4) | 0.468 |
| Use of cross-links | 13 (81.2) | 26 (78.8) | 0.841 |
| Screw & rod fracture | 5 (31.2) | 10 (30.0) | 0.946 |
| UIV Level (T10) | 2 (12.5) | 5 (15.1) | 0.804 |
| UIV Level (T11) | 3 (18.8) | 4 (12.2) | 0.534 |
| UIV Level (T12) | 5 (31.2) | 12 (36.3) | 0.724 |
| UIV Level (L1) | 4 (25.0) | 6 (18.2) | 0.579 |
| UIV Level (L2) | 2 (12.5) | 6 (18.2) | 0.614 |
| Muscle volume, T10 (mm2) | 1042±149 | 1315±143 | <0.001 |
| Muscle volume, T11 (mm2) | 1113±101 | 1445±176 | <0.001 |
| Muscle volume, T12 (mm2) | 1227±111 | 1603±230 | <0.001 |
| Muscle volume, L1 (mm2) | 1333±99 | 1783±326 | <0.001 |
| Muscle volume, L2 (mm2) | 1443±175 | 1905±303 | <0.001 |
Values are presented as number (%) or mean±standard deviation. PJK: proximal junctional kyphosis, BMD: bone mineral density, UIV: upper instrumented vertebra, C7PL: C7 plumb line, EP: early post-op, FF: final follow-up, SS: sacral slope, PT: pelvic tilt, PI: pelvic incidence