Let me describes the principles of mobilization of the nerves, as described by Butler.

The intensity of the maneuver should be related to the irritability of the tissue, patient response and change in symptom. The greater is the irritability, the more gentle is the response.

If the restriction is primarily tension, the stretch force is applied into the tissue resistance, held for 15 to 20 seconds, released and then repeated several times.

Neurological symptoms of tingling or increased numbness should not last when the stretch is released.

The application of the techniques requires positioning the individual at the point of tension (symptoms just begin), then either passively or having the patient actively move one joint in pattern in such a ways to stretch, then release the tension. Moving different joints in patterns, while maintaining the elongated position on the other joints, changes forces on the nerves.

After several treatments and tissue response is known, the patient is taught self stretching.

Have a look over the techniques for mobilizing the lower quadrant and sciatic nerve.

Straight Leg raising with Ankle Dorsiflexion:

Patient position and procedure.
Supine with lower extremity in straight leg raising position (SLR), add ankle dorsiflexion. Several variations may be done; ankle dorsiflexion, ankle plantar flexion with inversion, hip adduction, hip medial rotation and passive neck flexion. The maneuver may also be performed long sitting (slump sitting position) and side lying. These various positions of lower extremity and neck are used to differentiate tight and strained hamstrings from possible sites of restrictions or nerve mobility in the lumbosacral plexus and sciatic nerve.

Once the position that places tension on the involved neurological tissue is found, maintain the stretch position, and then move one of the joint a few degree in and out of stretch position, such ankle plantar flexion and dorsiflexion, or knee flexion and extension.

Ankle dorsiflexion and eversion places more tension on tibial tract.

Ankle dorsiflexion and inversion places tension on the sural nerve.

Ankle plantar flexion with inversion places tension on the common peroneal tract.

Adduction of one hip while doing the SLR places further tension on the nervous system because sciatic nerve is lateral to the ischial tuberosity; medial rotation of hip while doing SLR also increases tension on sciatic nerve.

Passive neck flexion while doing SLR pulls spinal cord cranially and places the entire nervous system on stretch.

Slump Sitting Stretch:

Patient position and procedure.
Slump sitting with neck, thorax, and low back flexed. Extend the Knee and dorsiflexion the ankle just to the point of tissue resistance and symptoms reproduction. Increase and release the stretch force by moving one joint in the chain a few degrees, such knee flexion and extension, or ankle dorsiflexion and plantar flexion.

Prone Knee Stretch:

Patient Position and procedure.
Prone the spine neutral (not extended) and the hips extended to 0 degree. Flex the knee to the point of resistance and symptom reproduction. Pain in the lower back or the neural signs are considered positive for upper lumber nerve roots and femoral nerve tension. Thigh pain could be rectus femoris tightness. It is important to not hyperextend the spine to avoid confusion with facet or compression pain. Flex and extend knee a few degrees to apply and release the tension.

Alternate position and procedure.
Side lying with the involved hip upper most. Stabilize the pelvis and extend the hip with knee flexed until symptoms are reproduced. Maintain the knee flexion, release, and apply tension across the hip by moving it a few degrees at a time.

Prevention:

These maneuvers especially the SLR with repetitive ankle dorsiflexion and plantar flexion, and the respective upper quadrant maneuvers may be used to prevent restrictive adhesions from developing if done early on in treatment after an acute injury or surgery.

Precautions and contraindications to Nerve tension Testing and Treatment:

Butler Cautions that there is incomplete scientific understanding of pathology and mechanisms occurring when mobilizing the nervous system. The clinician should always use caution.

Precautions:

Know what other tissues are affected by the position and maneuvers.
Recognize of irritability of the tissue involved and do not aggravate the symptoms.
Identify whether or not the condition is worsening and the rate of worsening. A rapid worsening condition requires greater care than a slowly progressing condition.
Use care if there is active disease or pathology affecting the nervous system.
Watch signs of vascular compromise. The vascular system is in close proximity with nervous system and at no time should show signs of compromise when mobilizing the nervous system.

Contraindications:

Acute or unstable neurological signs

Cauda equina symptoms related to spine including changes in bowel and bladder function and perineal sensation.

Spinal cord injury and symptoms.