| Group A (landmark based) | Group B (USG guided) | P value | |
| Age (years) | 53.35 (10.43) | 52.15 (11.15) | 0.186 |
| Gender | 0.069 | ||
| · Male | 132 (57.4) | 151 (65.7) | |
| · Female | 98 (42.6) | 79 (34.4) | |
| BMI (kg/m2) | 25.78 (4.61) | 26.69 (4.67) | 0.229 |
| Surgical discipline | 0.056 | ||
| · General Surgery | 124 (53.9) | 104 (45.2) | |
| · Obstetrics and Gynaecology | 3 (1.3) | 6 (2.6) | |
| · Surgical oncology | 1 (0.4) | 2 (0.9) | |
| · Orthopaedics | 79 (34.3) | 101 (43.9) | |
| · Urological surgery | 5 (2.2) | 9 (3.9) | |
| · Vascular surgery | 18 (7.8) | 8 (3.5) | |
| ASA grade | 0.427 | ||
| · 1 | 128 (55.7) | 115 (50) | |
| · 2 | 101 (43.9) | 113 (49.1) | |
| · 3 | 1 (0.4) | 2 (0.9) | |
| Ease of palpation of spine | 0.5 | ||
| · Easy | 103 (44.8) | 95 (41.3) | |
| · Moderate | 117 (50.9) | 120 (52.2) | |
| · Difficult | 10 (4.3) | 15 (6.5) |