This randomized prospective open comparative study was conducted in pain clinics of Mansoura University Hospitals from January 2022 to August 2022. The study was accepted by the Institutional Research Board of the Faculty of Medicine, Mansoura University (R.21.11.1534) on 21/12/1021 in compliance with the Helsinki Declaration and registered in the clinical trials.gov (NCT05184881) on 11/01/2022. Informed written consent was obtained from all study participants.
We included patients with cervical facet joint arthropathy not responding to conservative treatments. All patients should be more than 18 years old, and had a body mass index ˂ 30 with numeric rating scale (NRS) ≥ 4 and American society of Anesthesiology (ASA) Physical Status class I and II. Physical examination of the neck (kemp tests is a provocative test for diagnosing pain arising from facet joint by combined extension and rotation of the cervical spine) and imaging of the cervical spine (magnetic resonance imaging) were done to diagnosis the cervical facet joint arthropathy.
Patient refusal to participate, local or systemic sepsis, bleeding disorder, unstable respiratory or cardiovascular problems, history of drug abuse, allergy to used drugs, disturbed local anatomy and history of neurological or psychiatric disorders were excluded from our study.
All the patients were educated about the numerical rating score (NRS) to express their pain from zero to ten (where zero = no pain and ten = the worst pain).
Sample Size
Sample size was calculated using the Power Analysis and Sample Size software program (PASS) version 15.0.5 for windows 2017 using data got from a pilot study conducted on ten patients at Mansoura University Hospital using the numerical rating score (NRS) after injection as the primary outcome. Patients were allocated into two groups: CMBB group and the CRB group. NRS were 2.89 ± 0.23 for the CMBB group and 2.54 ± 0.53 for the CRB group. A sample size of 31 patients in each group was required to achieve 95% power (the probability of rejecting the null hypothesis when it was false or 1-β) in the proposed study using two-sided two-sample unequal-variance t-test with a significance level (the probability of rejecting the null hypothesis when it was true or α) of 5% and an effect size of 0.85. 10% drop-out was anticipated, so 35 patients were listed to each group.
Randomization
The participants were randomly grouped by a computer-generated list of random numbers on a scale of 1:1.The distribution results were placed in closed opaque envelopes and were held by the study administrator. On the day of the procedure, the anesthesiologist who performed the block took the envelope from the study manager.
Grouping (Fig. 1)
- CMBB group (n = 35): CMBB was performed at the affected dermatomal level and one level above 0.5 mL dexamethasone (4mg/1ml) and 0.5 mL 1% lidocaine in each level.
- CRB group (n = 35): CRB was performed using 2 mL dexamethasone (4mg/1ml) and 3 mL 1% lidocaine for each affected dermatomal level.
Techniques:
Patient entered the operating room, 20 G cannula was secured and 500 ml 0.9% normal saline was slowly taken. Non-invasive blood pressure, electrocardiogram (ECG) and pulse oximetry were monitored.
Cervical medial branch block (CMBB)
Patient was in the supine-position. Under fluoroscopic visualization, the waist of the articular pillars of the desired level was identified. After skin sterilization, a 25-gauge 3.5-inch spinal needle was introduced then the location of the needle tip at the mid-point of the waists of articular pillars was confirmed by fluoroscopy. After suction to avoid any blood aspiration, 0.5 mL dexamethasone (4mg/1ml) and 0.5 mL 1% lidocaine were injected at each level (Fig. 2). Because of each facet joint receives innervation from the medial branch of the same level and the one above. So the procedure was repeated at the level above the affected facet joint.
Cervical retrolaminar block (CRB)
Patient was in the prone-position. Under fluoroscopic visualization, the cervical lamina of the desired level was identified. After skin sterilization, a 25-gauge 3.5-inch spinal needle was introduced. The location of needle tip at the posterior aspect of the cervical lamina of the corresponding facet arthropathy level was assured by fluoroscopy. Aspiration was done to avoid blood suction then 2 mL dexamethasone (4mg/1ml) and 3 mL 1% lidocaine were injected (Fig. 3).
Then all patients were transferred to the postoperative care unit to be observed for half to one hour.
Outcomes
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Numerical rating score (NRS) was carried out for all patients before the procedure, 2 weeks, 2 and 3 months after the procedure (where zero equals no pain and 10 equals the worst pain).
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Neck Disability Index (NDI) was done before the procedure and 2 weeks after the procedure (8).
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Any complication has been monitored as vascular injury, pneumothorax and epidural or spinal injection.
Statistical analysis
SPSS (version 25) was used for the statistical analysis of the collected data. The normality of the data distribution was checked by Shapiro-Wilk test. Mean ± SD expressed the normally distributed continuous variables while categorical variables and non-normally distributed continuous were expressed as median and inter-quartile range or number and percentage (as appropriate). One-way ANOVA test was used for normally distributed continuous data and for abnormally distributed continuous data, Kruskal Wallis tests was used. Chi square test using the crosstabs function was used for categorical data. All tests were conducted with 95% confidence interval. Bivariate correlations using Spearman’s or Pearson’s correlation coefficient were assessed if needed depending on the nature of data. P ≤ 0.05 was considered statistically significant.