Background and Aims Herpes Zoster reactivation causes inflammatory and hemorrhagic reaction in the posterior roots of spinal nerves and sensitive ganglia. Postherpetic neuralgia (PHN)¹ is a neuropathic pain that occurs in 25% of patients older than 50^2,3. Pharmacological therapy is often uneffective; intrathecal steroid injections and nerve blocks may be tried⁴. Serratus anterior plane block (SAPB)⁵ could provide effective analgesia.

Methods We treated 2 female patients with PHN, unresponsive to medical therapies, 56 and 74 yo; pain was localized in the antero-lateral area of thorax, limiting free movements of ipsilateral arm. Pain was strong (NRS score 8 and 10), stabbing and burning, exacerbating in absence of stimuli and without relief during the night.

We performed an ultrasound-guided SAPB with 0.25%-levobupivacaine 30 ml and dexamethasone 8 mg at 5^th intercostal space.

Results Both patients had immediate pain relief: NRS was 2–3 after 10 minutes, 0–1 after 2 hours. Benefit was substantially maintained over time: at 48 hours, resumption of pain was mild (NRS 2) in the first patient, moderate (NRS 4–5) in the second; in this patient we decided to perform another injection. NRS finally decreased to 2–3 and there was no need for further injections. At two months there was absence of pain for both.

Conclusions Long-lasting SAPB with local anesthetic and steroids could be a safe and effective way to treat resistant PHN, and it should be performed as soon as possible to avoid incipit of chronic pain and improve patient quality of life and outcome. Further studies are necessary to confirm our preliminary data.