Among 59 patients with the presence of CRPS following a cerebrovascular accident (CVA), patients whose CVA occurred in 2009 or 2010 were selected.
The inclusion criteria were the presence of regional pain and sensory changes of hemiplegic unilateral upper extremity following a stroke; pain was associated with findings such as abnormal skin color, temperature change, abnormal sudomotor activity or edema; no distribution of the pain of a single nerve in the extremity. Seventeen subjects were excluded from this study if they had a history of upper extremity cellulitis, other autonomic nerve disease, peripheral nerve disease, bleeding disorder or severe cognitive impairment.
We therefore studied 42 patients with CRPS following stroke [19 right (45.3%) and 23 left (54.7%)] and patient signed informed consent. All 42 patients had the modified diagnostic criteria for CRPS as International Association for the Study of Pain (IASP).14
Twenty-five patients were women (59.6%) and 17 (40.4%) were men. All patients were divided randomly into US-guided SGB group (22 patients) and blind SGB group (20 patients). The mean age was 61.3±5.6 (range 34-77) years and 59.1±4.5 (range 36-71) years and the mean duration since stroke occurred were 2.8±1.1 (range 1-7) months, 2.3±0.9 (range 1-6) months, respectively ().
Clinical Characteristics of Subjects
Kapral et al.12
reported that US-guided SGB, by comparing with the blind technique, used a lower volume of local anesthetics and proved to be more effective. In this study, the blind SGB group patients and US-guided SGB group patients received the procedure using a volume of 10 ml of 0.5% lidocaine or 5 ml of 0.5% lidocaine, respectively. SGB was performed two times with an interval of 1 week between each treatments.12
The anterior paratracheal approach was used in the procedure on the cervical sympathetic chain without fluoroscopic guidance in blind group. A 22-gauge, 5-cm needle was perpendicularly inserted to the skin until bone contact was made and then withdrawn to rest anteriorly to the precervical fascia. The patient was encouraged to lie in the supine position for 3 minute after the injection and then developed injected-sided Horner's syndrome.15
In US-guided group, procedure was performed using same needle at same posture. After passing through the skin and subcutaneous tissue and stabilizing the needle, a 3-12 MHz linear array probe of HD11-XE® (Philips, Washington, USA) was used to verify the position of the needle. The needle was shown to be aiming towards the thyroid tissue anteriorly and then the esophagus posteriorly. At this point the needle was withdrawn, reinserted obliquely, and advanced with real-time US so that the needle tip lay anterior to the longus coli muscle (anterior to C6 transverse process) (). After negative aspiration, 5 ml of lidocaine 0.5% were injected.
Fig. 1 Ultrasonography imaging of the left stellate ganglion & prevertebral fascia (asterisks). Needle was advanced with real-time ultrasonography so that the needle tip will lie anterior to the longus coli. Th: Thyroid, LCo: Longus coli muscle, LCp: (more ...)
The primary outcome was evaluated by pain intensity and the amount of hand swelling. Pain intensity was evaluated by using a 10 cm visual analog scale (VAS) in which 0 represents 'no pain' and 10 represents 'the highest pain'. Determination of the volume of the hands (hand volume) was assessed by a hand volumeter. The hand volumeter set (8×13×28 cm) used was made of translucent material (acrylic), "Hand Volumeter" (Volumeter Unlimited, Phoenix, USA) and filled with room temperature water.
The volunteer was positioned beside the instrument during the procedure and the hand also positioned vertically, to avoid contact with the sides of the equipment. The hand was immersed slowly into the volumeter until it was immersed into water 2 cm above wrist crease. Additionally, the severity score for CRPS that was introduced by Harden in 2010 was evaluated as secondary outcome measure (Appendix 1
All these parameters were checked before procedure, after 2 weeks and 4 weeks following the SGB.
Statistical analysis was performed using Statistical Package for Social Sciences 11.0 version SPSS V11.0K (SPSS Inc., Chicago, USA). The Wilcoxon signed-rank test was used to compare VAS values and difference of hand volume before, 2 weeks and 4 weeks after the blockade for all patients and for each group. The Mann-Whitney U test was used for group comparisons on the mean differences of VAS values, hand volume and score of CRPS clinical severity. Null hypotheses of no difference were rejected if p-values were less than 0.05.