Clin Orthop Surg.  2014 Sep;6(3):324-328. 10.4055/cios.2014.6.3.324.

Feasibility of Nerve Stimulator as a Supplemental Aid for Lumbar Transforaminal Epidural Block

• Kim DH
• Lim CH
• Heo JY
• Jang YJ
• Choi YS

• KMID: 1794715
• DOI: http://doi.org/10.4055/cios.2014.6.3.324

Abstract

BACKGROUND
The purpose of this study was to evaluate the clinical feasibility of an electric nerve stimulator in a lumbar transforaminal epidural block.
METHODS
Using an electric nerve stimulator, transforaminal epidural blocks were performed in 105 segments of 49 patients who presented with lower back pain with radiating pain to lower extremities. The contrast medium was injected to delineate the nerve root after positioning an insulated needle at the intervertebral foramen under fluoroscopic guidance. Then, the nerve root was electrically stimulated with the insulated needle to confirm whether or not the same radiating pain was evoked.
RESULTS
Of the 105 foraminal segments, the same radiating pain was evoked at 0.5 mAh in 47 segments (44.8%), at 1.0 mAh in 22 (21.0%), at 1.5 mAh in 3 (2.9%), at 2.0 mAh in 15 (14.3%), at 2.5 mAh in 4 (3.8%), and at 3.0 mAh in 5 (4.8%). No response was observed in 9 segments (8.6%). The fluoroscopy revealed successful positioning of the needle in the patients with an evoked radiating pain over 2.0 mAh. The visual analogue scale (VAS) obtained for pain improved from a mean of 7.5 to 2.7 after the block (p = 0.001). In the 9 cases without response to electrical stimulation, the patients showed an improvement on VAS from 7.8 to 3.4 (p = 0.008) also.
CONCLUSIONS
A nerve stimulator can help to predict the accuracy of needle positioning as a supplemental aid for a successful lumbar transforaminal epidural block. It is sufficient to initiate a proper stimulation amplitude of the nerve at 2 mAh.

Keyword

Lumbar; Transforaminal epidural block; Electric nerve stimulator

MeSH Terms

Adult
Aged
Aged, 80 and over
Analgesia, Epidural
*Electric Stimulation Therapy
Feasibility Studies
Female
Humans
Low Back Pain/etiology/*therapy
*Lumbar Vertebrae
Male
Middle Aged
*Nerve Block
Radiculopathy/etiology/therapy
Spinal Diseases/*complications

Figure

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  Fig. 1 An insulated needle for the electric nerve stimulation with two lines: one line is a tube to instill contrast media and medicine, and the other is an insulated electrical line connected to the nerve stimulator device.

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  Fig. 2 Anteroposterior (A) and lateral (B) radiographs show a successful transforaminal epidural block.

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  Fig. 3 The nerve stimulator was turned on and the amplitude was increased from 0.5 mAh up to 3 mAh until a response was observed.

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