Table 5.

The equation of epidural needle depth using weight and height

Vertebral level and oblique angle	Epidural needle depth (mm)
Bilateral L5 TFEI at 15°	68.11 – 0.18 × height (cm) + 0.53 × weight (kg)
Bilateral L5 TFEI at 20°	72.65 – 0.21 × height (cm) + 0.56 × weight (kg)
Bilateral L5 TFEI at 25°	78.00 – 0.23 × height (cm) + 0.58 × weight (kg)
Bilateral L4 TFEI at 15°	72.29 – 0.23 × height (cm) + 0.58 × weight (kg)
Bilateral L4 TFEI at 20°	74.10 – 0.23 × height (cm) + 0.58 × weight (kg)
Bilateral L4 TFEI at 25°	77.70 – 0.25 × height (cm) + 0.61 × weight (kg)

TFEI: transforaminal epidural injection.