Shoulder pain is one of the most common musculoskeletal complaints and its prevalence
varies between 7-26%. Although some of the patients with shoulder pain show complete
recovery, pain persists in some of them. One of the most common sources of pain in these
patients is subacromial impingement syndrome (SIS) leading to rotator cuff pathology. The
multifactorial nature of pain in these patients makes the treatment of SIS difficult.
Central sensitization (CS) has been reported as one of the factors associated with
persistence of pain in patients with shoulder pain in different etiologies, especially in
the SIS. CS can be summarized as an increase in the response of neurons located in the
central nervous system to subthreshold stimuli and is the source of chronic pain in many
diseases. A decrease in the pressure pain threshold was observed in the painful shoulder
of 58 patients with experimental pain response in the shoulder.
In a meta-analysis of patients with shoulder pain, a decrease in pressure pain threshold
was found in 29-77% of patients, while SS was found in 11-24% of patients. The authors
emphasized the significant correlation of CS with poor treatment response. There is
increasing evidence that CS negatively affects various pain treatment responses,
including surgery. Considering the frequency of CS in patients with shoulder pain, it is
likely to have a negative impact on treatment response in these patients as well. One of
the most common treatments for SIS is subacromial/ intra-articular shoulder injection.
Although several factors have been identified in the prediction of shoulder injection
outcomes, the effect of pain sensitization on these procedures is not yet known.
This study was designed as a prospective single-center study. Patients aged 18-65 years
with rotator cuff lesions lasting more than three months and presenting to our physical
medicine and rehabilitation outpatient clinic will be included. Patients who have
received medical treatment as part of routine practice and have not had an adequate
response will be evaluated before and after injection. Injection preference will be
determined according to the patient primary complaint and lesion and will be administered
into the subacromial space or into the shoulder joint. There is no additional
interventional procedure due to the study. Patients will be divided into 2 groups with
and without central sensitization. A total of 18 patients were planned for each group.
The study will be conducted between March 2023 and June 2024.
Within the scope of the study, age, gender, body mass index, marital status, education
level and occupation of the participants will be recorded as demographic data. Clinical
evaluation includes pain duration, treatments received, pain intensity (numeric pain
scale 0-10), disease-related MRI/USG findings and the following evaluations.
All patients will be evaluated before injection, 1 week, 1 and 3 months after injection.
Within the scope of evaluation, Central Sensitization Scale, Quick DASH, SF-36 and
Hospital Anxiety and Depression questionnaire, pressure pain threshold, goniometric
shoulder range of motion measurement, hand grip strength (with Jamar hydraulic hand
dynamometer), numeric pain scale (no pain: 0- unbearable pain: 10) and pain intensity
will be recorded at each visit.
Data analysis will be performed by using the Statistical Package for the Social Sciences
(SPSS, version 23.0, IBM Corp., Armonk, NY, USA).
