Table 5.

Studies using paravertebral steroid injection/chemical neurolysis; stellate ganglion blocks; and RFA for PHN

Study	Interventional technique	Study design	Inclusion group	Method	Observations	Affiliation or disclosure
Naja et al.[30]	Paravertebral block	Case report	Mainly T1 extending to T4	Single injection at T1-T2 levels paravertebral catheter placement at T3 level. Bupivacaine 0.5% (19 mL) and clonidine 150 μg/mL (1 mL); repeated injection of same solution QOD for 3 weeks.	Before: VAS 7–8/10 with mood changes and sleep disturbance even while using ACT, NSAIDs, tramadol, carbamazepine 1200 mg/day, amitriptyline 30 mg/day, and gabapentin 3600 mg/day. After: pain free during an 8-month follow-up period.	Nil
Ding et al.[33]	SGB and SG-pulsed RFA followed for 6 months duration	RCT total 84, 48 each in two groups	PHN on the face or upper limbs more than 1 month duration	CT-guided SGB vs. SG-pulsed RFA, only once	VAS decreased in both groups (P < 0.05). In the SG-B group, VAS increased after 1 month, whereas in the SG-P group, VAS gradually decreased at later follow-up time points. VAS decreased more significantly in the SG-P group (P < 0.05). The total effective rates of the SG-B and SG-P groups were 64.3 and 83.3%, respectively.	This study was supported by the Natural Science Foundation of Liaoning Province (No. 20170541032) and Shenyang Young and Middle-aged Science and Technology Innovation Talent Support Plan (No. RC170045).
Milligan and Nash[34]	SGB	Observational study, 34 had PHN more 1 year duration and 8 had PHN < 1 year duration	PHN of thoracic, cervical, or trigeminal distribution.	65 SGB done on 42 patients.	Landmark-based SGB: anterior paratracheal approach to the ganglion was used, and 10 mL 0.25% bupivacaine injected.	12 (29%) showed no improvement, 11 (26%) were improved, and 19 (45%) had a good result. Patients with PHN < 1-year duration had better results.
				One patient received nine blocks.

ACT = acetaminophen, QOD = once every 2 days