The VLVCI group's outcome was similar to that of the HVCI group's, indicating that it might be used routinely in treating subacromial impingement syndrome. We found that the VLVCI had the same therapeutic and diagnostic effect as those of the HVCI, which has been a commonly used standard in general orthopedics. It was found that for the VLVCT group, 15 minutes post-injection of HVCI of mixed lidocaine solution, lidocaine overdose in blood serum could cause allergy, vasovagal syncope, or severe consequence complications. The difference in the VAS percentage after 15 minutes was not significant, indicating that the VLVCI could be used as an impingement test in the same way that a traditional impingement test with a main lidocaine solution component would be used. There has never been a study comparing VLVCI or pure corticosteroid without a mixed anesthetic solution. This is the first study to use VLVCI to increase the most potential steroid concentration effect, while avoiding the complications associated with lidocaine, the main component of HVCI and other different volume SCI comparative studies.
Triamcinolone acetonide (TMC) is a kind of corticosteroid that is commonly used in orthopedic procedures. Through reducing inflammatory mediators and influencing the cells engaged in inflammatory responses, the therapeutic effects affected both anti-inflammation and direct analgesic benefits [8]. This study assessed the efficacy of corticosteroid (TMC) injections at two different volumes, which are the most commonly utilized in subacromial injections for patients with subacromial impingement syndrome. Short-half-life steroids like TMC are often used in very low-volume corticosteroid injections. Despite the fact that the general results of the steroid shoulder injection in instances of shoulder pain are deemed good at this time. The injection of 1 ml (40 mg) TMC, both without lidocaine in addition to assessing mainly the response to the corticosteroid, resulted in improved range of motion (33 percent) and pain relief (61 percent) at the 2-week follow-up. From the theory, the onset of the action of corticosteroid is 24–48 hours, and the duration of action is approximately 2–3 weeks [9]. The short-term pharmacologic action of TMC in therapy seems to have a more rapid effect response, as evidenced by a comparison study of methylprednisolone (MTP) and triamcinolone (TMC), MTP or TMC, both without lidocaine, in evaluating only the corticosteroid response. Corticosteroid injections were delivered into the subacromial space in this study. When compared to the VAS pre-injection record, the VAS improved by 43 percent at 10 minutes post-injection, and the ROM improved by about 25 percent in TMC groups [10] even without the use of lidocaine, commonly combined with corticosteroids injections in pain relief in patients with shoulder pain due to be related to the TMC's high anti-inflammatory potency [11].
The signs and symptoms of lidocaine intoxication, which rely on plasma levels larger than 5 mcg/mL, include slurred speech, tinnitus, circumoral paresthesia, and feeling faint, are difficult to predict. If the concentration is higher than 10 mcg/mL, the patient may experience seizures or lose consciousness. At 15 mcg/mL, the heart and central nervous system become more depressed, leading to cardiac arrhythmias, respiratory arrest, and cardiac arrest at 20 mcg/mL [12]. Furthermore, an aminoamide local anesthetic group impaired the rotator cuff tendon fibroblast's cytotoxic mechanism and caused cell death by increasing the generation of reactive oxygen species, such as ropivacaine, bupivacaine, and lidocaine [12, 14].
Corticosteroid injections can also induce transient pain, skin atrophy, depigmentation, and septic arthritis, as well as have detrimental effects on intra-articular cartilage or tendon degeneration and even tendon ruptures [15]. When compared to low-volume CI, however, high-volume CI of lidocaine is associated with a higher risk of consequences (soft tissue irritation). Likewise, when corticosteroids are at lower concentrations, the steroid effect decreases. Subacromial injection was developed to reach a high drug concentration at the site of pathology while using less overall drug to avoid systemic side effects [4]. Currently, a combination of corticosteroid solution and local anesthetics is injected into a local soft tissue inflammatory site in clinical practice. However, the appropriate dosage, concentration, and volume in the SCI are still debatable. According to the study results of our previous systematic review and meta-analysis, high volumes (greater than or equal to 5 cc) of lidocaine in combination with corticosteroids for injection in subacromial impingement syndrome had a lower ASES, pain VAS, and risk of complications when compared to lower volumes (less than 5 cc). Low-volume CI may be a viable alternative as an injectable agent in subacromial impingement syndrome, considering its non-inferiority in terms of pain VAS score [7].
For subacromial impingement syndrome, the clinical outcome of ultrasound-guided subacromial injections was compared to blind subacromial injections. After a short-term follow-up, blind injections into the subacromial bursa were just as successful as ultrasound-guided injections in reducing pain and function in subacromial impingement syndrome. As a result, ultrasonography guiding for subacromial injections is no longer required [16]. The difference in injection precision, on the other hand, could be a source of heterogeneity. There is no significant difference in pain between high-corticosteroid injections using ultrasound guidance or landmark-guided injections using the posterior approach injection technique [17]. When comparing low-corticosteroid injections with ultrasound guidance to low-corticosteroid injections with landmark guidance, there is a significant difference in pain. As a result, we recommend using an ultrasound-guided approach for low corticosteroid injections to improve the outcome of corticosteroid injections in subacromial impingement syndrome, or a landmark-guided technique can be used in the case of high corticosteroid injections [4].
Our study's strengths include a prospective randomized control trial, long-term and short-term follow-up, and the use of a standardized and validated VAS, WORC, and DASH scores. This is the first study to compare the efficacy of corticosteroid injections in the subacromial impingement syndrome using HVCI and VLVCI (pure corticosteroid injection without analgesic solution combination). Data regarding all possible adverse effects were also collected. The follow-up rate was of a reasonably standard range, at approximately 85 percent in both of groups. We only had one patient that we were unable to include, due to the patient's decision to undergo the procedure on her own. Across all samples, less than 5 percent of participants to dropped out. In treatment of subacromial impingement syndrome. The follow-up period was short to long-term (6 months). Hence, the long-term effectiveness and adverse effects of treatment could be assessed.
The study's limitations were that firstly, the blinding technique was ineffective, as only assessors were used, and secondly, the trial was single-blinded, which may have resulted in underpowering for the primary and secondary outcomes. Different surgeons administered the corticosteroid injections. Although some publications suggested that low-volume corticosteroid injection (less than 5 ml) be utilized with the USG technique in low-CI, in order to improve the outcome, we only had a limited medical device and landmark guide injection was still a widespread practice among orthopedists in routine practice.