The aim of the present investigation is to study the status of the blood-nerve barrier in the carpal tunnel syndrome and cubital tunnel syndrome using gadolinium enhanced MRI. The subjects were 68 patients (92 hands) with idiopathic carpal tunnel syndrome and 21 patients (23 elbows) with cubital tunnel syndrome. The MRI equipment used was a 0.3-T permanent magnet. Using the SE method, T1-weighted axial images were obtained. Then, we intravenously injected gadolinium for enhanced images. We studied the relationship between nerve enhancement and the symptoms of the patients. Out of 92 hands with carpal tunnel syndrome, 74 hands (80%) showed enhancement of the median nerve. The patients had 58 hands classified as Grade I (sensory disturbance only) out of which 44 hands (76%) showed nerve enhancement , as did 25 out of 29 hands (86%) classified as Grade II (I + thenar muscle atrophy) and all 5 hands (100%) classified as Grade III (II + disturbance of opposition). Enhancement was more prominent in the patients with thenar muscle atrophy. All 23 elbows with cubital tunnel syndrome revealed enhancement of the ulnar nerve. Two elbows were categorized as grade I (sensory disturbance only), 12 as grade II (I + 1’st inter-osseus muscle atrophy), and 9 as grade III (II + claw finger deformity) In general, capillaries exist inside the endoneurial spaces of peripheral nerves. Intraneural homeostasis is maintained by the perineurium as a diffusion barrier and by the blood-nerve barrier existing in the endothelium. MRI could demonstrate intraneural enhancement at the site of nerve entrapment where intraneural edema resulted from an increase in the vascular permeability of the endoneurium. We conclude that gadolinium-enhanced MR imaging can detect morphological and functional changes of peripheral nerve in patients with entrapment neuropathy.
Periprosthetic osteolysis has attracted attention as a cause of loosening after arthroplasty. The aim of the present study was to examine inflammatory cell localization and the occurrence of apoptosis in granulation tissue from patients who required revision arthroplasty due to loosening caused by osteolysis. 7 patients were studied comprising 3 patients who underwent FHR and 4 patients who underwent THR. Their mean age at the time of surgery was 63.6 years. The mean period from their previous operation to revision was 8.8 years. Granulation tissue was collected from around the loosened implant fixed in 4% paraformaldehyde and embedded in paraffin. Sections were cut and were first stained with hematoxylin and eosin. Next, immunohistochemical studies were performed using the avidin-biotin complex method. CD45 was used as the primary antibody to detect T cells, and CD68 was used to detect macrophage-like cells. The activity of the macrophage-like cells was assessed with anti-I-NOS and anti-MMP-9. Apoptosis was investigated using anti-single-stranded DNA (ssDNA). Using another granulation tissue was stored at −80%C, DNA was extracted, and the presence of DNA fragmentation was detected by agarose gel electrophoresis. Vascularization and infiltration by a large number of inflammatory cells were seen along with large multinucleated osteoclas-like cells. Immunohistochemical studies revealed CD45-positive cells primarily around the blood vessels. The CD68-positive cells were mainly multinucleated cells. The multinucleated cells were i-NOS-positive in 4 patients, and were MMP-9-positive in 5 patients. The nuclei of many of the multinucleated cells were positive for ssDNA. Agarose gel electrophoresis of DNA showed a marked ladder pattern at the 170 base pair region. This finding indicated DNA fragmentation or apoptosis. Apoptotic cells were seen in granulation tissue harvested from around loosened implants suggesting that apoptosis may play a role in the pathophysiology of osteolysis.
