| 제목 |
Histological changes and neural elements in the subacromial bursa on patients with rotator cuff tear |
| 소속 |
Daegu Catholic University Medical Center, Department of Rehabilitation Medicine1, Daegu Catholic University Medical Center, Department of Orthopedic Surgery2, Daegu Catholic University Medical Center, Department of Pathology3 |
| 저자 |
Dong Rak Kwon1†, Gi Young Park1, Chang-Hyuk Choi2, Jun Young Kim2, Hoon Kyu Oh3, Dae Gil Kwon1, Dong Han Kim1* |
Abstract
Background
There has been a debate over removing subacromial bursa (SAB) during rotator cuff repair surgery. Subacromial bursectomy is particularly considered when the bursa is recognized as the main source of pain due to chemical and neural component. However, the neural elements of the bursa are still obscure in rotator cuff tear.
Purpose
To investigate neural elements of SAB in rotator cuff tear and to find out a clinical relevance of rotator cuff treatment based on the histological results.
Study design
Case-control study
Materials and Methods
Twenty patients with rotator cuff tears were recruited and evaluated for Visual analogue scale (VAS) score, duration of symptom, range of motion (ROM) including flexion, external rotation, and internal rotation. The size of tear was measured on MRI image. SAB specimens obtained during arthroscopic rotator cuff repair were studied using routine H&E and immunohistochemistry (S-100 protein and PGP 9.5 protein). SAB specimen for control group was obtained from 2 fresh cadavers that did not meet any of exclusion criteria and two patients with acute humeral shaft fracture. Mann-Whitney U test was applied to assess the difference between histological findings of the rotator cuff tear group and the control group. The correlation between histologic findings and clinical features were evaluated by Spearman’s correlation.
Results
The mean duration of symptom was 10.2 ± 6.4 months. Pre-operative average VAS score was 2.9 ± 1.2 (Table 1). The degree of pre-operative ROM in forward flexion, external rotation and internal rotation were 143.8 ± 19.5, 49.5 ± 23.1 and -4.3 ± 4.2, respectively. The size of tear was 2.0 ± 0.9 cm. For histological findings, the number of neural elements per low power field in the rotator cuff tear group (Figure 1) was significantly less than the control group (Figure 2) in both immunohistochemical stainings (S-100: 0.5 ± 0.7 vs 2.8 ± 0.5, p < 0.01; PGP 9.5: 0.4 ± 0.7 vs 3.5 ± 0.6, p < 0.01). In correlation analysis, the number of neural elements in PGP 9.5 staining was negatively correlated with ROM in forward flexion and external rotation.
Conclusion
Neural elements of SAB decreased in rotator cuff tear. The study revealed that chronic rotator cuff tear induces the degeneration of neural elements in SAB. Since SAB provides a proprioception for shoulder movement and healing of rotator cuff tendons, rotator cuff repair should be performed in time to prevent degeneration of nerve in SAB.
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Demographic data and clinical features
Representative S-100 protein and PGP 9.5 expression in subacromial bursa of rotator cuff tear patients. A and B. a few small atrophic peripheral nerve bundles (★) in inflammatory changed fibrous stroma (A, s-100 protein, X100. B. PGP 9.5, X100). C and D. No identified peripheral nerve bundle in severe inflammatory changed bursa tissue (C, s-100 protein, X100. D. PGP 9.5, X100).
Normal structure of subacromial bursa of control cadaveric specimen. A. Villous synovial membrane (arrows) and two peripheral nerve bundles (★) in fibro-adipose connective tissue (H & E, X40). B. S-100 protein immunohistochemical stain expression in the schwann cell (X200). C. PGP 9.5 immunohistochemical stain expression in the nerve axon (X200).
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