Table II.
Baseline characteristics of the patients.*
| Characteristic | Without spondylolisthesis | With spondylolisthesis | ||
|---|---|---|---|---|
| Fusion | Decompression alone | Fusion | Decompression alone | |
| Patients, n | 44 | 48 | 59 | 60 |
| Mean age, yrs (SD) | 65 (9) | 65 (8) | 67 (7) | 67 (7) |
| Female sex, n (%) | 26 (59) | 25 (52) | 44 (75) | 50 (83) |
| Smoker, n (%) | 7 (16) | 8 (17) | 9 (16) | 8 (14) |
| ASA grade, n (%) | ||||
| 1 or 2 | 36 (82) | 40 (87) | 48 (83) | 45 (76) |
| 3 | 8 (18) | 6 (13) | 10 (17) | 14 (24) |
| Mean ODI (SD) | 43 (16) | 40 (15) | 41 (13) | 41 (13) |
| Mean EQ-5D score (SD) | 0.39 (0.32) | 0.37 (0.31) | 0.37 (0.31) | 0.36 (0.29) |
| Mean VAS score for back pain (SD)† | 60 (25) | 59 (25) | 64 (21) | 64 (23) |
| Mean VAS score for leg pain (SD)† | 65 (19) | 60 (24) | 64 (22) | 65 (23) |
| Mean vertebral slip, mm (SD)‡ | 1.7 (2.3) | 0.6 (1.4) | 7.4 (2.8) | 7.4 (3.1) |
| Levels of surgery, n (%) | ||||
| 1 | 22 (50) | 27 (56) | 41 (69) | 39 (65) |
| 2 | 22 (50) | 21 (44) | 18 (31) | 21 (35) |
| Stenosis grade operated level(s) ‡ | n = 58* | |||
| Area ≤ 75, n (%) | 40 (91) | 46(96) | 56 (97) | 57 (95) |
| Schizas C-D, n (%) | 38 (88) (n = 43)** | 41 (85) | 51 (88) | 51 (85) |
| Mean dural sac area, mm2 (SD) | 43 (18) | 41 (18) | 38 (15) | 41 (17) |
| Disc degeneration adjacent level | n = 58* | |||
| Type I, n (%) | 0 (0) | 1 (2) | 0 (0) | 0 (0) |
| Type II, n (%) | 3 (7) | 4 (8) | 2 (3) | 6 (10) |
| Type III, n (%) | 20 (45) | 18 (38) | 23 (40) | 24 (40) |
| Type IV, n (%) | 19 (43) | 20 (42) | 29 (50) | 30 (50) |
| Type V, n (%) | 2 (5) | 5 (10) | 4 (7) | 0 (0) |
| Method of surgery, n (%) § | ||||
| Bilateral laminotomies | 10 (21) | 12 (20) | ||
| Central decompression | 38 (79) | 48 (80) | ||
| Uninstrumented PLF | 2 (5) | 4 (7) | ||
| Instrumented PLF | 41 (93) | 51 (86) | ||
| PLIF | 1 (2) | 4 (7) | ||
| Stenosis grade adjacent level (186 pts) ¶ | n = 40 | n = 44 | n = 51 | n = 51 |
| Area ≤ 75 mm, n (%) | 3 (8) | 4 (9) | 2 (4) | 3 (6) |
| Schizas C-D, n (%) | 1 (3) (n = 39)** | 3 (7) | 0 (0) | 2 (4) |
| Mean dural sac area, mm2 (SD) | 126 (38) | 123 (37) | 130 (34) | 138 (46) |
1 missing patient. Baseline MRI could not be localized.
Scores on the VASs for back pain and leg pain range from 0 to 100, with higher scores indicating more severe pain.
Only the narrowest/most slipped level is analyzed in cases of two level surgery.
All fusion patients also had central decompression. PLIF means Instrumented PLF+interbody fusion, posterior approach.
MRI axial cut lines of adjacent level were missing for 25 patients.
1 missing value. T2 axial not available. Area assessed from T1.
ASA, American Society of Anesthesiologists; EQ-5D, EuroQol five-dimension index; ODI, Oswestry Disability Index; PLF, posterolateral fusion; PLIF, posterior lumbar interbody fusion; SD, standard deviation; VAS, visual analogue scale.