| Neural Block and Partial Radiofrequency Lesioning on Dorsal Root Ganglion for the Management of Chronic Persistent Postherpetic Neuralgia |
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Jung Yul Park, Sang Dae Kim, Sang-Hyun Keem, Se Hoon Kim, Dong Jun Lim |
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Department of Neurosurgery, Korea University Medical Center, Ansan Hospital, Seoul, Korea |
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| Abstract |
Objective
Substantial number of patients with postherpetic neuralgia experience chronic, persistent pain of neuropathic nature
despite various treatments available. Thus, successful management of these patients is very challenging even to those
specializing pain. The object of this study was to validate usefulness of dorsal root ganglion (DRG) blocks followed by percutaneous radiofrequency (RF) lesioning in thes chronically disabling patients.
Materials and Method: A total of 40 patients, 26 males and 14 females, aged between 47 to 72 years old were included in
this study. All patients suffered from severe, intractable postherpetic neuralgia, all in the thoracic dermatome, more than 6
months (average 14.6 mos). These pains became refractory to medications and peripheral nerve blocks performed elsewhere.
DRG blocks and RF DR lesioning were performed in corresponding levels under local anesthetics. First, with patient prone,
DRGs were targeted with 22G electrodes, with 5-mm bared tips, and these were confirmed radiographically with injection of
contrast dye. Then, 3cc mixture of steroid and lidocaine, in case with blocks, were injected transforaminally. RF lesioning was
done followed by physiologic testings and instillation of 0.5mL of lidocaine. Lesions comprised of 42℃ initially, for the testing,
then 67 degrees for 90 seconds for final lesioning. Successful pain relief was considered when more than 50% of pain relief
from previous pain. All patients were followed more than six months.
Results
All patients tolerated well from both procedures. Initial diagnostic/therapeutic DRG blocks showed more than 50% of
pain relief in 32 patients, but with varying degree in duration of pain relief, ranging 2 days to 3 months. Average 2.5 blocks were
performed in these patients before RF lesioning was performed. Four of 8 patients, who showed no significant pain relief
initially showed more than 50% of pain relief from second procedure. Remaining four patients showed no change. In overall,
DRG blocks followed by RF DRG lesioning provided significant pain relief in 32 of 40 patients (80%) for more than 6 months.
Two of these patients underwent radiofrequency thalamotomy with successful results. Remaining 2 patients who showed about
30-40% pain relief are under consideration for either DREZtomy or spinal cord stimulation but refused any further therapeutic
modalities. There were no complications related to procedures. However, 6 patients complained transient exacerbation of pain
or soreness that persisted for about a week.
Conclusion
Series of DRG blocks and percutaneous RF DRG angliotomies seemed to provide significant pain relief in majority
of patients with intractable postherpetic neuralgia involving thoracic region. Therefore, they should be considered next when
conservative measurements, including peripheral nerve blocks, fail to relieve pain or become refractory. |
| Key Words:
Postherpetic neuralgia, Dorsal root ganglion, Nerve block, Radiofrequency, Lesioning. |
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