Medical Care
The financial implications for treatment of postherpetic neuralgia (PHN) are becoming more important as the population ages. Dworkin et al examined annualized costs for persistent pain in patients with herpes zoster. Annualized costs were $4917 for commercially insured patients, $2696 for Medicare patients and $9310 for Medicaid patients. [7]
A clinical trial has shown that a live-attenuated varicella-zoster virus vaccine is effective against herpes zoster (HZ) and postherpetic neuralgia (PHN). Brisson estimates that for 65-year-olds, the number needed to vaccinate (HZ vaccine efficacy = 63%, PHN vaccine efficacy = 67%, no waning) to prevent a case of HZ, a case of PHN, an HZ death, a life-year lost, and a quality-adjusted life-year lost is estimated to be 11 (90% Crl: 10-13), 43 (90% Crl: 33-53), 23,319 (90% Crl: 15,312-33,139), 3762 (90% Crl: 1650-4629), and 165 (90% Crl: 105-197), respectively. Results of this study show that the main benefit of HZ vaccination is prevention of morbidity caused by pain. [8]
In 2011, the Food and Drug Administration (FDA) lowered the approved age for use of Zostavax to 50-59 years. Zostavax was already approved for use in individuals aged 60 years or older. Annually, in the United States, shingles affects approximately 200,000 healthy people aged 50-59 years. Approval was based on a multicenter study, the Zostavax Efficacy and Safety Trial (ZEST). [9] The trial was conducted in the United States and 4 other countries in 22,439 people aged 50-59 years. Participants were randomized in a 1:1 ratio to receive either Zostavax or placebo. Participants were monitored for at least 1 year to see if shingles developed. Compared with placebo, Zostavax significantly reduced the risk of developing zoster by approximately 70%.
In 2017, the FDA approved Shingrix (zoster vaccine recombinant, adjuvanted) for the prevention of shingles in adults aged ≥50 years. Approval is based on findings from a Phase III clinical trial program assessing its efficacy, safety, and immunogenicity in 38,000 patients. Data from a pooled analysis of 2 clinical trials demonstrated efficacy against shingles greater than 90% across all age groups, as well as sustained efficacy over a follow-up period of 4 years. [10, 11, 12]
Chen et al found vitamin C plasma concentrations are lower in 38 patients with postherpetic neuralgia compared with 39 healthy volunteers (P< .001). In this study, restoration of vitamin C concentrations decreased spontaneous pain (but not brush-evoked pain) by 3.1 on a numeric pain scale in the postherpetic neuralgia group compared with placebo treatment (P< 0.001). The authors concluded that vitamin C status is a component in postherpetic neuralgia and is a component involved in spontaneous pain relief. [13]
In a small study by Kanai et al, lidocaine 4% ophthalmic drops were administered to 24 patients with ophthalmic postherpetic neuralgia in a crossover manner. A significant reduction in eye and forehead pain was observed in patients who received the lidocaine ophthalmic drops. Analgesic onset was noted via a visual analog scale within 15 minutes after administration and persisted for a median of 36 hours (range, 8-96 h). [14]
Surgical Care
See the list below:
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Dorsal root entry zone (DREZ) lesions have been used.
Efficacy - Improvement rate is 20% in long-term studies.
Complications - Gait disturbances are experienced by 12% of treated patients.
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Hypopigmented rash in thoracic dermatome of postherpetic lesion.
