|Year : 2020 | Volume
| Issue : 1 | Page : 27-33
Comparison of cervical medial branch nerve block versus trigger point injection in patients with chronic neck pain
Aftab Hussain1, Hammad Usmani1, Mohd Fakhrul Huda2, Guru Prasad Dureja3, Dhruv Bibra3
1 Department of Anaesthesiology, Pain Clinic, Jawaharlal Nehru Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
2 Department of Neurosurgery, Jawaharlal Nehru Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
3 Delhi Pain Management Centre, New Delhi, India
|Date of Submission||04-Sep-2019|
|Date of Acceptance||02-Dec-2019|
|Date of Web Publication||16-Apr-2020|
Prof. Hammad Usmani
Department of Anaesthesiology, Pain Clinic, Jawaharlal Nehru Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Background: Annual prevalence of chronic neck pain in general population averages between 30%-50%. Among various causes of chronic neck pain cervical facet joint involvement accounts for about 54% to 67%. Interventional procedures such as medial branch nerve block, trigger point injections and dry needling have been described for management of chronic neck pain. Objectives: To determine the clinical effectiveness of cervical medial branch block and trigger point injections in the management chronic neck pain. Design: Randomized, double blinded, prospective study conducted at two different centers in India, Pain Clinic, Department of Anaesthesiology, J.N. Medical College hospital, Aligarh Muslim University, Aligarh, Delhi Pain management centre, New Delhi, India. Methods: Data analysis was done from a total of 60 patients with 30 patients in each group. Group CMB received cervical medial branch block and group TP received trigger point injection with levobupivacaine (0.25%) and triamcinolone (20mg) at two different levels. There was no sham group. Outcome Measure: Numeric rating scale (NRS), Neck Pain Disability Index (NDI), weekly analgesic requirement and subjective evaluation of patients was done at 1st week, 3rd week, 6th week and 12th week of follow up and compared with the pre-procedure value. Results: Significant pain relief was observed in both the groups of study, at 1st week of study, compared to baseline. Further follow up showed significantly better pain relief in patients receiving medial branch nerve block than patient receiving tender point injections at 3rd, 6th week and 12th week. NDI score in-group CMB was significantly better as compared to group TP at 3rd, 6th and 12th week follow up. Subjective evaluation of pain showed significantly greater proportion of patient with good to excellent pain relief in group receiving medial branch block. Analgesic requirement was significantly less in group CMB compared to group TP during follow up. Conclusion: Cervical medial branch block with local anaesthetic and steroid may provide long-term relief in patients with chronic neck pain than trigger point injection with no major incidence of complications in either group.
Keywords: Cervical medial branch block, chronic neck pain, trigger point injection
|How to cite this article:|
Hussain A, Usmani H, Huda MF, Dureja GP, Bibra D. Comparison of cervical medial branch nerve block versus trigger point injection in patients with chronic neck pain. Indian J Pain 2020;34:27-33
|How to cite this URL:|
Hussain A, Usmani H, Huda MF, Dureja GP, Bibra D. Comparison of cervical medial branch nerve block versus trigger point injection in patients with chronic neck pain. Indian J Pain [serial online] 2020 [cited 2020 Jul 5];34:27-33. Available from: http://www.indianjpain.org/text.asp?2020/34/1/27/282554
Disclaimer: Editor-in-Chief had no involvement in the peer-review process of this article.
| Introduction|| |
Chronic neck pain is a common phenomenon second only to low back pain in its frequency. Evidence indicate an annual prevalence of neck pain averages between 30% and 50%. This entity is not only a common cause of disability but also causes a significant social, economic, and health impact on our society.,,
There are no specific epidemiologic studies to describe the frequency of causes of neck pain. However, various studies have implicated zygapophysial (facet joints) as the source of pain in 54%–67% of patients with chronic neck pain.,,,,, Based on responses to control diagnostic block in accordance with the criteria established by the International Association for the Study of Pain, facet or the zygapophysial joints have been implicated as the source of chronic pain in 39%–67% of patients with chronic neck pain of heterogeneous origin.,
Cervical facet joints are synovial joints with fibrous capsules located in pairs on the back of the spine. The nerves supplying the facet joints are the medial branches of cervical dorsal rami. When the joints are damaged or inflamed, this nerve may get irritated causing pain in the neck, shoulders, and arms.,, Cervical medial branch (CMB) nerve blocks are believed to interrupt nociceptive discharge, block of reflex arc of the afferent limb neurons, and axonal transport mechanism.,
Tender points are discrete, focal, hyperirritable spots located in a taut band of skeletal muscle which act as trigger points (TrPs). Acute trauma or repetitive microtrauma may lead to the development of stress on muscle fibers and the subsequent formation of TrPs. Palpation of the TrP elicits pain directly over the affected area or causes radiation of pain toward a reference zone and a local twitch response.
TrP injection has been shown to be one of the most effective treatment modalities to inactivate TrPs and provide prompt relief of symptoms.,,
The present study was designed to evaluate the comparative efficacy of therapeutic CMB block and TrP injection with local anesthetic and steroid in patients of chronic neck pain.
| Materials and Methods|| |
The present study entitled “Comparison of cervical medial branch nerve block versus trigger point injection in patients with chronic neck pain” was conducted at two interventional pain management centers in India: Pain Clinic, Department of Anaesthesiology, Jawaharlal Nehru Medical College and Hospital, Aligarh Muslim University (AMU), Aligarh, and Delhi Pain Management Centre, New Delhi, India, during February 2014 to October 2016.
Selection of patients
Following approval by the board of studies, Department of Anaesthesiology, and Ethical Committee of J. N. Medical College and Hospital, AMU, Aligarh (BOS: 22/02/14), sixty patients suffering from chronic neck pain of at least 3-month duration attending the Pain Clinic at either of the centers between February 2014 and October 2016 were enrolled for this study. Patients were equally divided into two groups of thirty patients each.. Written and informed consent was taken from each patient after explaining the procedure and the risk involved.
Inclusion criteria consisted of patients over 18 years of age with neck pain of at least 3-month duration, nonradiating nature, following dermatomal distribution & not associated with discogenic symptoms and neck stiffness. American Society of Anesthesiologists (ASA) Grade I and II, with neuroradiologic studies that rule out presence of any invasive lesion or disc-related disease, and willingness of patients to actively participate in this study.
Exclusion criteria include patients aged >75 years, patients receiving anticoagulants or hypersensitivity to local anesthetic agents, patients with coagulopathies or history of recent surgical procedure in the cervical spine (within last 3 months), infection overlying the entry area, psychiatric disorders or major depression, or other severe medical illness, and pregnant or lactating mothers.
A sample size of 30 patients in each group was based on power analysis in which alpha level was fixed at 0.05 and anticipated estimate of effect for a desired statistical power level of 0.8. A minimum required sample size per group was calculated to be 30 and minimum total required sample size was calculated to be 60. After obtaining written informed consent, 60 ASA I and II patients were randomly divided into two equal groups of 30 each using a computer-generated randomized schedule.
In Group CMB (n = 30), patients received CMB nerve blocks, whereas in Group TP (n = 30), patients received TrP injections. All the patients were reassessed at least 1 week before the procedure. They were started on fixed-dose regimen of pregabalin 150 mg/day in 2–3 divided doses and tablet tramadol (37.5 mg) and paracetamol (325 mg) combination (Ultracet) on, as and when required basis.
The patients were trained in the Numeric Pain Rating Scale (NRS) of 0–10 score to describe the extent of pain before and pain relief after the block was performed. The pain level of the patients was assessed in pre- and posttreatment period using the NRS and Neck Pain Disability Index (NDI) score. The patients were also asked to express their level of satisfaction through a set of questionnaire at the 1st, 3rd, 6th, and 12th weeks of follow-up visits.
After completely explaining the procedure and written informed consent, patients in Group TP received TrP injection with triamcinolone (20 mg) and levobupivacaine (0.25%) at two levels. Patients in Group CMB received CMB blocks at two levels with triamcinolone (20 mg) and levobupivacaine (0.25%).
The CMB was performed in lateral position with patients lying with their painful side uppermost [Figure 1]. The procedure was carried out under the guidance of fluoroscopy. Each median branch nerve was infiltrated with 1 ml of levobupivacaine (0.25%) and triamcinolone (Kenacort 20 mg) at two levels. A 3-cm long, 22-gauge needle was used to perform medial branch block through lateral approach. Needle placement was confirmed fluoroscopically before injecting the drug [Figure 2].
A similar approach was followed for TrP injection patients for blinding of the study groups. Once a TrP has been located, we isolate that point with a pinch between the thumb and the index finger or between the index and middle fingers. Using sterile technique, a 22-gauge, 3-cm needle is then inserted 1–2 cm away from the TrP so that the needle may be advanced into the TrP at an acute angle of 30° to the skin.
Follow-up was done at the 1st, 3rd, 6th, and 12th weeks through pain clinic visits. Parameters recorded were NRS, NDI score, subjective evaluation of pain, requirement of analgesics, and complication, if any.
Statistical analysis was done using SPSS 20 (IBM Corp., Armonk, N.Y., USA) and MS Excel and MS office 2010 (Redmond, WA, USA). Patients' demographic characteristics were analyzed using unpaired t-test and Chi-square test. The results were expressed in numbers, percentage, mean, and standard deviation as appropriately.
The NRS and NDI measurement for pain after the block at different time points was compared with the preprocedure values. A paired t-test was used to assess the pre- and posttreatment NRS scores and NDI measurements at baseline versus 1st, 3rd, 6th and 12th weeks. Subjective evaluation of the patients was evaluated using Fisher's exact test.
The t-test was used to compare the mean pain scores between the groups at the 1st, 3rd, 6th, and 12th weeks. Analysis of variance was used for comparison of mean among the groups.
The difference between the two groups in the study was explored in terms of estimate of effect, appropriate confidence interval, and P value. For all statistical analyses, the confidence interval was set at 95% (P < 0.05).
| Observation and Results|| |
[Figure 3] illustrates the participant flow and their random allocation into two groups of 30 patients each. The demographic profile of the patients was comparable in the two study groups [Table 1].
In Group CMB block, NRS scores at the 1st, 3rd, 6th, and 12th weeks showed a significant reduction in pain scores from baseline [Table 2]. There was a considerable reduction in pain score in Group TP injection during the 1st week of the study period; however, at the 3rd, 6th, and 12th weeks of follow-up, pain relief was not statistically significant [Table 3].
|Table 2: Numeric Pain Rating Scale scores in cervical medial branch group before and after treatment|
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|Table 3: Numeric Pain Rating Scale scores in trigger point group before and after treatment|
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A comparison of NRS scores between the two groups did not show significant differences during the 1st week after treatment. However, at the 3rd, 6th, and 12th weeks of follow-up period, significant differences in NRS scores were observed between the two study groups [Figure 4].
|Figure 4: Numeric Pain Rating Scale scores in study groups before and after treatment|
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NDI scores showed a significant reduction in scores in Group CMB at the 1st, 3rd, 6th, and 12th weeks, as compared to baseline [Table 4].
|Table 4: Neck Pain Disability Index scores in cervical medial branch group before and after treatment|
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However, in Group TP, the NDI score was not statistically significant compared from baseline at the 3rd, 6th, and 12th weeks of follow-up [Table 5]. Intergroup comparison of NDI scores also showed significantly more improvement at the 3rd, 6th, and 12th weeks of follow-up in Group CMB as compared to Group TP [Figure 5].
|Table 5: Neck Pain Disability Index scores in trigger point group before and after treatment|
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|Figure 5: Neck Pain Disability Index scores in study groups before and after treatment|
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Patient satisfaction score at the 3rd, 6th, and 12th weeks of follow-up showed significant differences between the two groups, with Group CMB scoring above Group TP [Table 6]. Only eight patients required rescue analgesics in Group CMB as compared to 18 in Group TP [Table 7]. Minor complications such as pain and tenderness at injection site were noted in few patients in both the groups which were found to be statistically insignificant. No major complication was noted in any of the patients in either study group.
| Discussion|| |
Chronic neck pain is a common ailment in adult population, second only to low back pain in frequency., Linton et al. described chronic neck pain as disabling as low back pain. The lifetime prevalence of chronic neck pain has been reported between 26% and 71% with a 12-month prevalence ranging from 30% to 50%., Various studies on impact of chronic neck pain on general health showed 14% of the patients reporting Grade II to IV neck pain with high pain intensity and disability.,,, Facet joints have been implicated as the source of chronic pain in 54%–67% of the patients.,, Thus, it is clear that chronic neck pain is a nonfatal chronic pain condition associated with a significant economic, social, and health impact on our society.
Although many patients get pain relief from conservative measures, some have intractable pain, which is not responsive to oral analgesics. More aggressive treatment options have been considered for such patients. Different interventional procedures used to manage chronic neck pain include tender or TrP injections, dry needling, facet joint injections, medial branch nerve blocks, and radiofrequency nerve ablation of medial branch nerves. The use of steroid with local anesthetics is justified by various studies supporting its role in dampening C-fibers and suppressing neuronal discharge.,,
TrP injections are commonly performed interventional pain procedure; however, objective diagnostic criteria for TrP are still lacking. The prevalence of TrPs in patients varies anywhere between 30% and 93%. Hong reported that either injections lidocaine or dry needling of TrP provided immediate pain relief if local twitch response is elicited.,
The evidence for long-term benefits of medial branch nerve blocks is strengthened by various studies., CMB blocks are technically easier to perform than intra-articular joint blocks. The medial branch is located at the waist of the articular pillar and is more easily accessible than the joint, which can be narrowed by degenerative changes.
Bogduk and Marshalnd, Dwyer et al., and Barnsley et al. performed CMB blocks for the diagnosis as well as for the treatment of chronic neck pain. They also confirmed the hypothesis of the cervical zygapophysial joint as a source of chronic neck pain.
A systematic review of the therapeutic studies conducted by Falco et al. showed that the evidence for CMB blocks is Level II-1 with a strong recommendation of 1B or 1C. Therapeutic medial branch blocks demonstrated effective short- and long-term pain relief for chronic cervical facet joint neck pain.
The outcome results of our randomized, controlled trial of therapeutic CMB nerve blocks and tender point injection in patients with function-limiting chronic neck pain showed a significant pain relief and improvement in functional status at the 1st week of follow-up in 93% of the patients in the group which received CMB block and 86% in the group treated with TrP injection. However, at the 3rd, 6th, and 12th weeks of follow-up, 87%, 86%, and 83% of the patients treated with CMB block (Group CMB) showed a significant relief in pain and disability, whereas only 56%, 54%, and 47% of the patients treated with TrP injections (Group TP) showed a significant relief at the 3rd, 6th, and 12th weeks of follow-up, respectively. These observations demonstrated the potential usefulness of CMB blocks in providing long-term pain relief in patients of chronic neck pain not relieved by conservative and pharmacological measures.
Barnsley et al., described the specificity of CMB block with small dose of local anesthetic in diagnosis of cervical facet joint pain. The drug always reached the target nerve, and it did not affect any other diagnostically important structures. This was further evaluated by injecting contrast medium. Windsor et al. studied the electrical stimulation referral pattern of CMB producing a discrete reproducible referral pain pattern differing from other etiologies causing the pain.
Our study showed consistent pain relief in 90%–83% of the patients who received CMB block at the 1st, 3rd, 6th, and 12th weeks of follow-up period. None of the patients received a repeat block during the 12-week follow-up period of study.
The results of our study were comparable to previously published prospective studies illustrating the effectiveness of therapeutic CMB blocks in patients with chronic neck pain. Manchikanti et al. conducted a trial on effectiveness of CMB blocks in patients with chronic neck pain. One hundred consecutive patients receiving CMB blocks were followed up for 12 months, and a significant relief varied from 92% at 3 months to 56% at 12 months. Another study conducted by Machikanti et al. in patients of chronic neck pain showed that CMB block was found to provide significant relief in 80%–93% of the patients at 3 months, 6 months, and 12 months of follow-up period. However, during the follow-up period, patients were offered repeated block as and when required, and there was also a lack of randomization in their study. There was a significant improvement in employment status among the patients.
A similar study conducted by Tsai et al. in patients who received CMB block for shoulder pain observed a significant decrease in NRS scores from baseline (7.0 ± 1.4 to a score of 1.2 ± 1.7; P < 0.05) at 1-month follow-up. In our study, pain scores in patients receiving CMB block (NRS and NDI) had significantly decreased at the end of 12 weeks of follow-up period.
In 1994, Hong investigated the effects of injection of local anesthetic agent or dry needling into a TrP of the upper trapezius muscle in 58 patients. TrP injection with 0.5% lidocaine was recommended because of reduction in the intensity and duration of postinjection soreness compared with that produced by dry needling. Hong and Hsueh compared the responses to TrP injection between patients having both myofascial pain syndrome caused by active TrPs and fibromyalgia syndrome and vice versa. Outcome was assessed by subjective pain intensity and pain threshold, and range of motion was assessed before, immediately after, and 2 weeks after TrP injection. TrP injection was found to be a valuable procedure for pain relief for patients in both the groups. Muñoz-Muñoz et al. investigated the presence of active TrP in greater number and relation to TrP to pain. They concluded that referred pain elicited by the TrPs resulted in symptoms of neck pain.
A recent prospective study by Xie et al. on the efficacy of lidocaine injection in the treatment of chronic neck pain caused by TrP showed that lidocaine injection therapy for TrP significantly reduces degree and frequency of neck pain at 6-month follow-up. In our study, 86% of the patients receiving TrP injection showed a significant pain relief at the 1st-week follow-up, but only 56%, 54%, and 47% of the patients treated with TrP injections (Group TP) showed a significant pain relief at the 3rd, 6th, and 12th weeks of follow-up period.
Both the procedures used in our study were of low risk and can be administered multiple times to provide relief in patients of chronic neck pain. Complications observed during the procedures could be mostly procedure related. Minor complications such as postinjection soreness and tenderness at the injection site were observed in two patients in Group CMB and one patient in Group TP for a few hours. No major complication involving neurovascular structures was observed in any of the patients in our study.
The limitations of our study include its short-duration follow-up, a relatively smaller number of patients in each group, and lack of a placebo group. Since this study was designed as a randomized, blinded trial, enrolling a smaller number of patients was acceptable in evaluation of effectiveness of the interventional techniques.,,, In practice, controlled comparative blocks are easier to perform and thus more likely to be used by a physician not able to perform placebo-controlled blocks. The issue of ethics, feasibility, and cost also pose challenges to the inclusion of a placebo group. Further, when compared with placebo-controlled blocks, the false-positive rate has been shown to be very low. Therefore, a diagnosis and treatment based on comparative blocks is unlikely to be wrong.
Another limitation of our study was that of lesser accuracy as the sample size of 30 was calculated using an a = 0.05 and power of study 80%. Precision and accuracy could have been better and had the sample size been calculated using a power of 90%.
| Conclusions|| |
To conclude, CMB block provided significantly better pain relief in patients of chronic neck pain as compared to TrP injection. The quality of life also improved significantly in patients treated with CMB block. However, large-scale randomized, controlled clinical trials are needed to further study the role of cervical facet joints in the pathogenesis of myofascial TrPs in patients of chronic neck pain.
Financial support and sponsorship
Conflicts of interest
Dr. Aftab Hussain is an Associate Editor & Prof. (Dr.) Hammad Usmani is Editor-in Chief of IJPN. They have no involvement in peer review process of article.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]