Case report of patient with neuropathic thigh pain succesfully treated with local injection

15th March 2007 at 12:41 GMT by Dr Christopher A. Jenner MB BS, FRCA. Permalink.

Case report of patient with neuropathic thigh pain succesfully treated with local injection of the lateral cutaneous nerve of the thigh

Case report of patient with neuropathic thigh pain succesfully treated with local injection

A 59 year old lady presented to the Pain Clinic with pain in the left anterior thigh. In her past medical history she had had breast cancer some 4 years earlier. This had been treated with a mastectomy, local radiotherapy and chemotherapy. Unfortunately, approximately 2 years later, she was found to have a single metastatic nodule which was found in the pubic bone, which gave her pain.

Local radiotherapy treatment

She was treated with local fractions of radiotherapy to this single metastasis. The radiotherapy was beneficial and the pain from the metastasis diminished. However, unfortunately, she was left with pain in the left thigh. This pain was described as a constant, burning pain in the left part of the left anterior thigh.

Examination findings in patients with neuropathic thigh pain

On examination, she had burning pain and pain on light touch (allodynia) and exaggerated pain on pin prick (hyperalgesia) over the anterolateral part of the left thigh, corresponding with the L1/2 dermatome and the territory of the lateral cutaneous nerve of the thigh.

Diagnosis of neuropathic thigh pain

My impression was that this lady had had radiation damage to the lateral cutaneous nerve of the thigh when this was applied to the solitary pubic metastasis. The lady was already on Gabapentin 300 mg three times a day. This was increased to 400 mg twice a day and a lateral cutaneous nerve of the thigh block was performed.

Lateral cutaneous nerve of the thigh block

This involved identifying the exit point of this nerve which is approximately 10 cm inferior and medial to the anterior superior iliac spine. The procedure was performed using aseptic technique, 2 mls of 1% Lignocaine was infiltrated into the skin and then a small 23 gauge needle was inserted underneath the skin and a mixture of 3 mls of 0.5% Bupivicaine and 80 mg Depo-Medrone was carefully infiltrated into the area where the lateral cutaneous nerve of the thigh exits through the skin. The discomfort immediately started to dissipate.

Follow-up after lateral cutaneous nerve of the thigh block

The patient was seen for follow up at 3 months and reported that the pain had entirely subsided. The patient was discharged from the clinic.