Central Hypersensitivity in Patients With Subacromial Impingement Syndrome

Abstract

Objective To investigate the presence of primary and secondary hyperalgesia among subjects with chronic subacromial impingement syndrome (SIS) compared to pain-free controls. Design Cross-sectional design. Setting Outpatient rehabilitation clinic, urban, academic medical center. Participants Volunteer sample of 62 subjects (31 with SIS, 31 controls). Interventions Not applicable. Main Outcome Measures Pressure-pain thresholds (PPTs) were measured at the middle deltoid of the affected/dominant arm (primary or secondary hyperalgesia) and the middle deltoid and tibialis anterior of the unaffected/non-dominant side (secondary hyperalgesia) in SIS and healthy controls, respectively. Differences in PPTs were analyzed by Wilcoxon Rank Sum test and with linear regression analysis controlling for gender, a known confounder of PPTs. Results After adjusting for gender, subjects with SIS had significantly lower PPTs than controls at all locations. Controls had a 1.4 kg/cm2 (95% CI 1.2 – 1.5) higher PPT at their affected shoulder than those with SIS, a 0.7 kg/cm2 (95% CI 0.5 – 0.9) higher PPT at their non-affected shoulder, and a 1.1 kg/cm2 (95% CI 1.1 – 1.2) higher PPT at their contralateral tibialis anterior. Observers were not blinded to patient groupings but were blinded to level of applied pressure. Conclusion This study provides further evidence that SIS patients have significantly lower PPTs than controls in both local and distal areas from their affected arm consistent with primary and secondary hyperalgesia, respectively. Data suggest the presence of central sensitization among subjects with chronic SIS.

Topographical pressure pain sensitivity maps of the shoulder region in individuals with subacromial pain syndrome

“…Some authors suggest changes in central (Hidalgo-Lozano et al, 2010;Paul et al, 2012) and peripheral (Alburquerque-Sendín et al, 2013) nervous systems in individuals with unilateral SAPS. These previous studies observed hyperalgesic responses to different stimuli i.e., pressure and thermal, at different anatomic regions in individuals with unilateral shoulder pain compared to matched healthy controls (Alburquerque-Sendín et al, 2013;Coronado et al, 2011Coronado et al, , 2014Hidalgo-Lozano et al, 2010;Paul et al, 2012;Sanchis et al, 2015). Our results do not support the presence of these hyperalgesic responses to mechanical stimuli in patients with clinical diagnosis of SAPS.…”

“…There is evidence suggesting the presence of unilateral regional shoulder mechanical hyperalgesia in these patients (Alburquerque-Sendín et al, 2013), whereas multiregional and bilateral shoulder pain hyperalgesia has been also documented (Hidalgo-Lozano et al, 2010;Paul et al, 2012). Both peripheral (Alburquerque-Sendín et al, 2013) and central (HidalgoLozano et al, 2010;Paul et al, 2012) sensitization mechanisms are suggested in playing a role in SAPS.…”

“…Furthermore, increased mechanical sensitivity can also occur on the nonaffected side as a sign of central sensitization . Although bilateral hyperalgesia has already been identified in unilateral shoulder pain (Hidalgo-Lozano et al, 2010;Paul et al, 2012;Coronado et al, 2014;Sanchis et al, 2015), results are still conflicting which increases the interest of research in this area.…”

“…Central sensitization refers to persistent changes in the central nervous system following prolonged peripheral nociception (Arendt-Nielsen and Graven-Nielsen, 2008). Both peripheral (Alburquerque-Sendín et al, 2013) and central (Hidalgo-Lozano et al, 2010;Paul et al, 2012;Sanchis et al, 2015) sensitizations have already been identified in individuals with SAPS. It is suggested that both mechanisms can contribute to the development and maintenance of chronic pain (Graven-Nielsen and ArendtNielsen, 2010).…”

The Importance of Night Pain for the Effectiveness of Theurapotic Ultrasound in the Sub acromial Impingement Syndrome: A Randomized Controlled Trial

“…Patients with SIS have significantly lower pain pressure thresholds than do controls in both local and distal areas from their affected arm consistent with primary and secondary hyperalgesia, respectively. Data suggest the presence of central sensitization among subjects with chronic SIS [17]. Sleep disturbance which is very frequently seen in chronic pain patients can increase pain perception.…”