Recent Advances in the Diagnosis of Myofascial Pain Syndrome

Dear Editor, I had the privilege of reading the review article titled ‘Myofascial Pain Syndrome: A Comprehensive Systematic Literature Review on Diagnostic Approaches, Treatment Modalities and Recent Advances’ (doi: 10.4103/ijpmr.ijpmr_76_24). It is indeed a comprehensive work that thoughtfully describes the recent treatment modalities for Myofascial Pain Syndrome (MPS). However, I felt that the diagnostic approaches could have been addressed in greater depth, and my purpose in writing this letter is precisely to highlight that aspect. Since there are no universally accepted, objective and standardised criteria, the diagnosis of MPS remains largely based on subjective clinical evaluation, which is inherently challenging and variable across clinicians.[1] Recent research has attempted to develop more objective diagnostic measures. Methods involving controlled stimuli and pain responses – such as quantitative sensory testing, algometry and conditioned pain modulation – offer insights into sensory abnormalities associated with MPS. Imaging modalities, including thermography (liquid crystal and infrared), have been explored to visualise muscle tissue changes, assess blood flow and measure stiffness differences in taut bands. Vibration elastography provides another non-invasive approach to assess stiffness variations. Electromyography has identified spontaneous electrical activity at trigger points, and certain biomarkers have also been studied as potential indicators of myofascial trigger points (MTrPs).[1,2] Despite their promise, these modalities have not yet gained widespread clinical adoption, primarily due to practical limitations. I would particularly like to highlight infrared thermography (IRT), which has demonstrated potential but is accompanied by challenges. By mapping skin surface isotherms through infrared emission detection, IRT provides proportional information about local skin temperature. A strong correlation exists between temperature variations and pressure pain thresholds in MPS. Being non-invasive, IRT employs infrared cameras with subsequent image analysis. Notably, thermal asymmetries >0.5°C–0.7°C are associated with musculoskeletal dysfunction, including MTrPs, and dynamic thermography can enhance the precision of assessing pathological skin microcirculation.[3] For the accuracy of thermal imaging studies, strict adherence to technical, individual and environmental conditions is essential. These include standardised room conditions, patient preparation, acclimatisation periods and consistency in equipment calibration and region-of-interest selection. Guidelines for such protocols have been developed by thermography associations such as the American Academy of Thermology, the European Thermological Society and the Polish Society of Thermographic Diagnostics in Medicine. For instance, acclimatisation periods between 5 and 20 min, and controlled room temperatures between 18°C and 25°C are recommended. Non-compliance with these conditions significantly reduces the specificity of IRT in detecting MTrPs.[3] Pressure algometry has also been studied for assessing both localised and widespread musculoskeletal pain. By quantifying the pain pressure threshold, it provides a numerical measure of MTrP sensitivity.[4] Although algometry is more reliable than manual palpation, it cannot differentiate active from latent trigger points. Nevertheless, it remains valuable for evaluating the therapeutic efficacy of interventions and demonstrates a positive correlation with thermography findings.[3] In conclusion, while the reviewed article offers important insights into the therapeutic management of MPS, I believe that highlighting diagnostic modalities would further enrich its clinical impact. Objective diagnostic tools – including quantitative sensory testing, algometry, electromyography, elastography, and especially IRT – hold promise for reducing variability and enhancing diagnostic reliability. Yet, their optimal use demands adherence to standardised protocols and awareness of methodological limitations. I sincerely commend the authors for their meticulous review and thank you, respected Editor, for the opportunity to contribute these reflections. I hope that this perspective adds constructively to the ongoing dialogue on improving diagnostic accuracy in MPS. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.