Background: Postherpetic neuralgia (PHN) is often refractory to existing treatments. Pulsed radiofrequency
(PRF) is known to be effective for treating neuropathic pain. In common, the targets of PRF treatment were
the segmental dorsal root ganglion (DRG) neurons responsible for the pain. A potential complication that
can occasionally occur with PRF treatment is damage to the adjacent tissue and organ. The effectiveness of
the angulus costae as a puncture site for PRF has not been tested in thoracic PHN treatment.
Objective: The goal of this study was to investigate the therapeutic efficacy and safety of PRF for
treating thoracic PHN through the puncture of the angulus costae.
Study Design: Prospective, randomized, double-blinded study.
Setting: Department of Anesthesiology, Xinhua Hospital, Shanghai Jiaotong University School of
Medicine.
Methods: Ninety-six patients with thoracic (T2-11) PHN were equally randomized assigned into 2
groups. The electrode needle punctured through the angulus costae of each patient guided by x-ray; PRF
at 42°C for 120 seconds was applied after inducing paresthesia involving the affected dermatome area.
PRF was applied in the PRF group (n = 48) twice. It was also applied in the sham group (n = 48) twice
without radiofrequency energy output. The treatment was done once a week for 3 weeks. Tramadol was
used for flare pain when the visual analog scale (VAS) ≥ 3.
Outcomes Assessment: The therapeutic effect was evaluated by VAS, SF-36 health survey
questionnaire, side effects (type, frequency, and onset time) before treatment, at days 3, 7, and 14,
and at months one, 2, 3 and 6 after PRF. The average of tramadol (mg/d) administrated within the first
month after treatment was also recorded.
Results: The postprocedure VAS scores in the PRF group were significantly lower than those in the sham
group and lasted for 6 months after treatment (P < 0.05). The SF-36 score, such as physical functioning,
physical role, bodily pain, general health perceptions, social function, emotional role, and mental health index
were significantly improved until 6 months after treatment in the PRF group compared to the sham group (P <
0.01-0.05). The average dosage of tramadol administered (mg/d) within the first month after treatment was
also significantly reduced in the PRF group compared to the sham group (P < 0.05). There were no obvious
signs of pneumothorax, bleeding, infection, or other severe side effects in either group (P > 0.05).
Limitations: Single center study, relatively small number of patients.
Conclusions: The strategy that the angulus costae be used as the PRF puncture point of an electrode
needle and the final localization of the needle tip as determined by sensory testing is an effective and
safe therapeutic alternative for thoracic PHN treatment. Benefits include that the procedure is minimally
invasive, provides short-term pain relief, and improves quality of life.
Clinical Trial Registration: NO ISRCTN25588650.
Key words: Thoracic, postherpetic neuralgia, pulsed radiofrequency, angulus costae
Efficacy and safety of pulsed radiofrequency modulation of thoracic dorsal root ganglion or intercostal nerve on postherpetic neuralgia in aged patients: a retrospective study