The Evaluation of Erector Spinae Plane Block for the Pain Control of Thoracic Postherpetic Neuralgia

Erector spinae plane block is new interfascial plane block, and can be applied to management of thoracic neuropathic pain syndromes. The target of needle is deeper(or anterior) to the erector spinae muscle. So it is more safe and simple technique than prior technique, thoracic paravertebral block. The aim of this study is the evaluation of erector spinae plane block comparison to prevertebra block.

This study is single-blind because it is not possible to blind the practitioner performing the injection. Subjects were randomly assigned to the erector spinae plane block group (group E) and the thoracic paravertebral block group (group P) by a random random number table, and the possibilities for belonging to any group were all the same and can not be artificially controlled by researchers. Before the procedure, a resident who does not know of this study records the patient's pain and painDETECT. and on follow-up four weeks visits, PGIC scale is checked. The erector spinae plane block or thoracic paravertebral block should be performed after receiving the informed consent of the patient. Because of the large difference between the skilled and unskilled patients, the procedure in this study is performed by only one skilled practitioner.

The subjects were randomly assigned to erector spinae plane block group (group E) and thoracic paravertebral block group (group P), and the assigned results are unknown. The Outcomes Assessor is not related to the study, and does not know its contents.

In group E, The patient was placed in a sitting position and a high-frequency linear ultrasound transducer was placed in a longitudinal orientation 3 cm lateral to the thoracic spinous process. Three muscles were identified superficial to the hyperechoic transverse process shadow as follows: trapezius, rhomboid major, and erector spinae. An 8-cm 22-gauge block needle was inserted in a cephalad-to-caudad direction until the tip lay in the interfascial plane between transverse process and erector spinae muscles, as evidenced by visible linear spread of fluid between erector spinae muscles and the bony acoustic shadows of the transverse process. A total of 20 mL of 0.25% ropivacaine with dexamethasone 5mg was injected here.

2) In group P, an appropriate thoracic spinous precess is located by positioning the probe in the transverse plane. Then the probe is moved laterally to locate the transverse process. The probe is manipulated slightly caudad or cephala to locate the intercostal space. The transverse process is visualized medially with the pleura dipping under the inferolateral aspect. The internal intercostal membrane, which is contiguous with the superior costotransverse ligament, was generally seen as a thin, radiopaque line extending from the transverse process, creating a wedge-shaped pocket, which represents the thoracic paravertebral space. A 22-gauge, facet-tip needle is advanced, in plane, from the lateral aspect of the ultrasound probe. When the needle pierced the internal intercostal membrane, and after aspiration demonstrated the absence of air or blood, 10 mL 0.25% ropivacaine with dexamethasone 5mg deposited in 5-mL increments.

1. in both groups, the patient is asked to score the pain before the procedure and 4 weeks later. And then the change of pain score is recorded. NRS(numeric rating scale, on a scale of 0 to 10, with 0 being no pain at all and 10 being the worst pain imaginable)

2. the patient is asked to painDETECT score the pain before the procedure and 4 weeks later. And then the change of painDETECT score is recorded. painDETECT Questionnaire. The first five questions ask about the gradation of pain, scored from 0 to 5 (never = 0, hardly noticed = 1, slightly = 2; moderately = 3, strongly = 4, very strongly = 5). Question 6 asks about the pain course pattern, scored from -1 to 2, depending on which pain course pattern diagram is selected. Question 7 asks about radiating pain, answered as yes or no, and scored as 2 or 0 respectively. The total score summed each subscales is between -1 and 38, indicates the likelihood of a neuropathic pain component. A score less than 12 indicates that pain is unlikely to have a neuropathic component, while a score more than 19 suggests that pain is likely to have a neuropathic component.

3. the patient is asked to PGIC, 7 scales about overall improvement of pain relief 4 weeks later. Patient's global impression of change(PGIC) scale. Since beginning treatment at this clinic, the change (if any) in ACTIVITY LIMITATIONS, SYMPTOMS, EMOTIONS, and OVERALL QUALITY OF LIFE, related to your painful condition. (No change =1, almost the same = 2, a little better = 3, somewhat better =4, moderate better =5, better =6, a great deal better =7)

Inclusion Criteria: 1. Inclusion criteria were patients who had chest wall post herpetic neuralgia, with moderate and severe pain and received appropriate antiviral therapy. Exclusion Criteria: Patient refusal Patients who did not receive appropriate antiviral therapy Patients with mild pain Heavy skin eruption (no healthy area for needle entry) and infection at site of injection. Patients with history of renal, hepatic diseases, coagulopathy, diabetes Patients taking chemotherapy and/or radiotherapy Patients with history of steroid therapy Patients taking narcotic analgesics Patient who does not understand the study because of illiteracy or language problems. Abnormal findings in peripheral blood test (CBC, ESR, CRP, PT/aPTT)