Shoulder pain is one of the most common causes of pain in the musculoskeletal system . Pain and restriction in active movements of the shoulder remarkably decreases the quality of life of patients . Rotator cuff pathologies and impingement syndrome are the most common causes of shoulder pain . ACJ is a small joint; however, it is an important part of the shoulder girdle complex . Pain and restriction in the arm lifting and cross body movements can manifest . The initial treatment of symptomatic ACJ disorders often involves conservative therapies. Physical therapy modalities, analgesics, non-steroid anti-inflammatory drugs (NSAIDs), and corticosteroid (CS) injections to the ACJ can be applied . Corticosteroid injections are commonly used in the management of shoulder pain thanks to their potent anti-inflammatory effects and rapid response to injection . However, the use of these injections is limited due to pain, vasovagal reactions, altered serum glucose levels, facial flushing, and systemic side effects such as osteoporosis . In addition, there are some reports suggesting that CS injections should not be performed frequently due to local complications such as tendon ruptures . The studies have shown that CS can reduce pain and increase the range of motion of the joint with sustainable effects in the long-term [5,9].
Pulsed radiofrequency (PRF) therapy has been reported to offer an effective and simple treatment method in the management of chronic shoulder pain, and a single session can provide pain relief for a long period, thereby, facilitating functional rehabilitation . It has been considered a non-destructive therapy, which does not cause neural injury . In addition, PRF has been reported to be a useful treatment option in patients who are unresponsive to conservative therapies or not suitable for surgical therapy or those who are willing to undergo non-surgical treatments for chronic shoulder pain . Although there are numerous studies in the literature reporting good outcomes with PRF application to the suprascapular nerve in the management of chronic shoulder pain [13,14], no study using PRF to the subacromial area and ACJ is available. In this study, we aimed to compare the effectiveness of CS injections and PRF therapies applied to the ACJ and the subacromial area in the long-term.
Material and Method
Medical charts of 65 patients who were admitted to the physical medicine and rehabilitation (PMR) and algology outpatient clinics of our hospital between January 2013 and December 2015 were retrospectively reviewed. The study protocol was approved by the institutional Ethics Committee (The decision number is 2011-KAEK-25 2016/15-03). The study was conducted in accordance with the principles of Declaration of Helsinki.
Inclusion criteria were: patients with chronic shoulder pain due to impingement syndrome (diagnosed with both clinical examination findings and Magnetic Resonance Imaging (MRI)) (for >3 months), and those aged between 18 and 60 years, also patients who respond to the diagnostic block by using 3 ml prilocaine (more than 50% reduction in VAS scores).
Exclusion criteria were: patients who received PMR, injections or PRF therapy to the shoulder area in the past one year, the presence of malignancy, radicular pain and cervical myofascial pain syndrome, history of acute trauma, previous history of fracture in the shoulder to be treated, previous surgery or metal implants to the affected shoulder, inflammatory rheumatic disease, uncontrolled arterial hypertension, metabolic syndrome, diabetes mellitus, mental retardation, use of antidepressants, and autoimmune diseases.
The present study examined 40 patients meeting the inclusion criteria were analyzed in 2 different groups; Group 1: CS (n=20) and Group 2: PRF (n=20). Pre-treatment (W0) and post-treatment follow-ups at one (W1), four (W4), 12 (W12) and 24 weeks (W24) were carried out using Visual Analogue Scale(VAS), Shoulder Pain And Disability Index (SPADI) scores and Beck Depression Inventory(BDI) Scale tests.
All invasive procedures were performed by the same physician. On the patient who was in prone position, the C-arm fluoroscopy was adjusted toward the lateral and cephalo-caudal direction until the ACJ was identified within sight. After cleaning the access site, local anesthesia was administered to the cutaneous and subcutaneous tissue using 3 ml prilocaine. A 22 G 10 cm needle was guided to ACJ under fluoroscopy (Figure 1).
Pulsed Radiofrequency Procedure
PRF procedure was applied with 5 mm active-tip RF needle at 45 V, 200 ms, 42 0C for 120 s (2 min) ACJ and subacromial area 120 sn (2 min) (NeuroTherm, Middleton, MA, USA).
A 3-ml of the mixture of bupivacaine 0.25% (4 mL) and methylprednisolone 40 mg (1mL) was administered to the subacromial area, and a 2-ml of the mixture was administered into the ACJ. In both groups, no posttreatment complications were observed during the follow-ups.
The VAS score was used to evaluate the pain severity, the SPADI for to measure shoulder discomfort and BDI for to evaluate depression.SPADIs’ evaluation includes two parts: pain and disability. Part 1 (shoulder pain index (SPI)) includes five questions in the pain subgroup and measures the pain experienced by the patient over the previous week using VAS (0 no pain, to 10 most severe pain). Part 2(shoulder disability index (SDI)) is the disability subgroup and includes eight questions and measures the degree of difficulty (0 no difficulty, to 10, requires help) in the shoulder movements of the patient during the last week. SPADI includes 13 questions, and zero point refers to maximal well-being, and 130 points refers to maximal sickness. We evaluated each part of the SPADI; SPI, SDI, and total SPADI separately. The validity of SPADI was demonstrated .
The Beck depression inventory (BDI) aims to measure behavioral findings of the depression in adults and adolescents. This inventory is composed of 21 items each ranked from mild to severe disease form. The patients are asked to mark the item that best fits their situation, and the total score is calculated by the sum of scores achieved in each item. 0-13 points indicate no depression, 14-19 points indicate mild depression, 20-28 points indicate moderate depression, and 29-63 points indicate severe depression. The total score on this scale is 63 points .
In addition, the patients did not receive any additional analgesic agents, PMR, or another intervention during follow-up.
Analysis of the collected data was performed using IBM SPSS 22.0 statistical package program. When the study data were evaluated, the Pearson chi square (χ2) or Yates χ2 tests were used in the comparison of the qualitative variables, in addition to descriptive statistical methods (frequency, percentage, mean and standard deviation). Normal distribution of the data was tested using Shapiro-Wilk test. Independent Samples t-test (t-test for independent groups) was used in between-groups comparisons while variables were found normally distributed. When a normal distribution was not found, the Wilcoxon signed rank test for group comparisons and Mann Whitney U test for comparisons between groups were used. Variance analysis with repeated measurement (ANOVA) was used in in-group comparisons. Values with a probability of (P) α<0.05 was accepted as significant.
Of 40 patients, 14 were males, and 26 were females. There was no statistically significant difference between the two groups concerning age, gender, body mass index (BMI), duration of pain, side and week 0 (W0) values of VAS, SPI, SDI, SPADI and BDI (p<0.05) (Table 1). There was a statistically significant improvement in all the evaluation parameters at W1, W4, W12, and W24 compared to W0 in both groups (p<0.05) (Table 2).
The comparison of the groups with each other there was no statistically significant difference between the VAS, SPI, SDI, SPADI and BDI values at W1, W4, W12, W24 (p>0.05) (Table 2).
Although the present study showed significantly successful outcomes with both procedures, compared to baseline values, there was no statistically significant difference in the outcomes at W0, W1, W4, W12, and W24 follow-up visits between the two groups.
Impingement syndrome accounts for 44 to 65% of patients with chronic shoulder pain . Initial therapy in impingement syndrome involves a conservative approach, whereas CS injections are commonly used . Many studies have attempted to reveal the efficacy of CS injections commonly used in the management of chronic shoulder pain [18,19]. Among these studies, Göksu et al. included 61 patients in their study in which one group received triamcinolone acetonide + bupivacaine injection to the subacromial area, while the other group received Kinesio-taping three times with three days off . The patients were assessed using the VAS, Passive range of motion (PROM), and SPADI. The authors found a statistically significant difference in the efficacy of CS injections at 4 weeks after therapy. Similarly, another study evaluated the outcomes of CS injections to the subacromial area under the guidance of ultrasonography, and the authors reported that this approach was effective in the short-term at 6 weeks during follow-up .
Furthermore, several studies have addressed possible local and systemic side effects of CS injections to the subacromial area [7,20,21]. In a study, Hong et al. showed no statistically significant difference between 20 mg and 40 mg doses and concluded that preferred use of a low dose at the initial stage . In another study, 40 patients were divided into two groups: Group 1 received tenoxicam injections to the subacromial area once weekly for three weeks, and Group 2 received a single dose of methylprednisolone to the subacromial area.Both groups showed that these therapies were effective. However, the authors recommended tenoxicam as the first-line therapy thanks to its superior safety profile . In the present study, patients who were considered to have a higher risk due to side effects of CS were excluded, and patients included in the study received a single CS injection.
Often subacromial area is evaluated in the impingement syndrome, and the therapy is directed to this area. It has been reported that rotator cuff problems can be avoided if ACJ OA is treated in the early period. In the study by Hossain et al. which evaluated the efficacy of CS injections to the ACJ, 25 patients with primary ACJ OA received intra-articular CS injections and were followed for five years . The authors reported that CS injections in the treatment of primary isolated ACJ OA had prolonged effects sustaining up to 12 months. In another study, 58 patients with isolated ACJ symptoms received lidocaine + CS injection. In the study above, favorable outcomes at one month were observed in 28% of the patients. The patients who benefited from the injections were also followed for 42 months, and favorable outcomes were sustained in the long-term in most cases . The present study attempted to increase the efficacy of therapy using injections to the subacromial area and ACJ in patients with chronic shoulder pain due to impingement syndrome.
Furthermore, as a novel treatment modality, PRF therapy is commonly used in the management of pain in today’s practice. It is a non-neurolytic, effective, and easily applicable method which offers long-term relief with a single session of therapy [10,11]. This type of therapy to the nerves has also been reported to stimulate nociceptive nerve endings and, thereby, prolonged depression in the first synapses. In addition, PRF therapy has been suggested to increase the production of anti-inflammatory cytokines by producing an electric field on the immune cells, and progression of this process is regulated by increasing levels of pro-inflammatory cytokines such as interleukin (IL)-1b, tumor necrosis factor-alpha (TNF-α), and IL-6 . However, intra-articular use of PRF therapy in pain management is limited to case reports in the literature [8,22]. In a report of three cases who received therapy to the glenohumeral joint, Ozyuvaci et al. reported PRF therapy as a recommendable treatment modality .
In addition, PRF studies in the management of chronic shoulder pain often evaluated the application to the suprascapular nerve rather than application into and around the joints [14,23]. In a series of 40 patients who received PRF therapy to the suprascapular nerve due to impingement syndrome, the patients were evaluated using the Likert scale and Oxford Shoulder Score for six months, and it was found to be an effective treatment modality and the effects of this therapy were sustained in the long term . In another study including 57 patients with chronic shoulder pain resistant to medical treatment, PRF was applied to the suprascapular nerve for 480 seconds, indicating a statistically significant recovery during follow-up .
Moreover, in a randomized controlled trial carried out by Gofeld et al. in 22 patients with chronic shoulder pain, the first group received lidocaine and the second group received lidocaine + PRF therapy to the suprascapular nerve during a six-month follow-up . The authors reported significantly better outcomes in the PRF group. Another study which induced lesion using PRF to the suprascapular nerve under fluoroscopy in 13 patients with chronic shoulder pain showed that this therapy could be a potential treatment option in patients suffering from chronic shoulder pain, provided long-term pain control, and reduced the amount of analgesics .
In the present study, PRF therapy was applied to the subacromial area and ACJ. The success of the present study can be attributed to the effects of therapy on nerve endings in the ACJ and subacromial area. The discussion in this manuscript was limited due to lack of studies in the literature that evaluated the application of this therapy to the subacromial area and ACJ.
Small sample size and lack of a placebo group were the main limitations of the present study.
In conclusion, our study results showed that CS injections and PRF therapy applied to the ACJ and subacromial area were effective during six- month follow-up in patients with chronic shoulder pain due to impingement syndrome. But statistical significance superiority to each other was not determined.
Scientiﬁc Responsibility Statement
The authors declare that they are responsible for the article’s scientiﬁc content including study design, data collection, analysis and interpretation, writing, some of the main line, or all of the preparation and scientiﬁc review of the contents and approval of the ﬁnal version of the article.
Animal and human rights statement
All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. No animal or human studies were carried out by the authors for this article.
Conflict of interest
None of the authors received any type of financial support that could be considered potential conflict of interest regarding the manuscript or its submission.
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