Objective
This study investigated the association in pressure pain threshold (PPT) of affected upper extremity with range of motion (ROM) and numeric pain rating scale (NRS) of shoulder movements. We hypothesized the low value of PPT of affected upper extremity was associated with disability or limited ROM of shoulder joint and pain during shoulder movements.
Methods
Ten patients who visited outpatient in department of rehabilitation medicine after more than 1 month of breast cancer surgery were included We excluded patients with shoulder pain or other neuromuscular problems in shoulder joints prior to breast cancer surgery.
All patients were assessed Questionnaire about Disabilities of the Arm, Shoulder and Hand (Quick DASH) score, ROM and NRS at shoulder flexion, abduction, external rotation, internal rotation. The PPT was determined by using the Algometry (Commander®, JTECH Medical, Midvale, UT, United States) to gradually increase the pressure on both supraspinatus muscles (middle point over the fossa of the scapula), pectoralis major muscles (middle point under clavicle), biceps brachii muscles (halfway between the coracoid process and the radial head), lateral epicondyles (2cm distal to the epicondyle), masseter muscles (muscle belly of masseter), 3rd finger metacarpal (MCP) joints which were determined by reference to fibromyalgia criteria, and was obtained by measuring the mean pressure 3 times when the patients began to feel pain at first. We calculated the ratio value of PPT using following method; unaffected side-affected side/unaffected side.
The relationship between the score of Quick DASH, ROM, and NRS of shoulder and PPT was statistically analyzed using SPSS version 20.0 (IBM SPSS Inc., Armonk, NY, USA).
Results
The ROM at shoulder flexion was strong correlation with PPT of pectoralis major muscle (r=0.893, p<0.01). There was a statistically significant correlation between Quick DASH score and PPT of pectoralis major muscle (r=0.770, p<0.05). However, there was no statistically significant relationship between NRS in shoulder movements and PPT of all assessed muscles.
Conclusion
The decrease in shoulder flexion after breast cancer surgery is more severe when pectoralis major muscle is susceptible to pressure pain. Therefore, shoulder flexion exercise should be prioritized among the shoulder movements after breast cancer surgery, and it is also important to treat pain of pectoralis major muscle among the muscle around the shoulder preferentially. Further study is needed to larger sample size after breast cancer surgery. |
