“…PNFS has been described in a couple of case reports,58,59,67 smaller cases series,56,62,65 and some studies with higher case numbers 61,64,68. A retrospective multicentre study on 111 patients with chronic low back pain, FBSS, cervical pain, postherpetic neuralgia, tension headache, and some patients with trigeminal neuralgia or thoracic pain showed that the relatively best pain relief was obtained in patients with thoracic back pain, whereas the least pain relief was seen in patients with tension headache.…”