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Biomedical subjects

T S Chow

Publications and source records attributed to T S Chow.

4 recordsLinked to original sources
PubMed2001

Nanoadhesion between rough surfaces.

A model is developed to describe the adhesion between deformable fractal surfaces over the mesoscopic realm that covers the familiar range of interest in nanotechnology from atomic dimensions to microns. This model helps us gain a quantitative understanding of the variation of adhesion with surface energy, with microstructure of rough surfaces, and with bulk deformability. The present analysis goes beyond the Gaussian distribution of asperity heights by investigating the influence of the microstructure of self-affine fractal surfaces. Our calculation reveals that orders of magnitude increase in adhesion are possible as the roughness exponent decreases.

Journal Article↗
PubMed1997

Unusual foreign body causing quadriparesis: case report.

OBJECTIVE AND IMPORTANCE: An unusual foreign body traversing the spinal canal at the foramen magnum level is described. Interesting radiological findings and a review of nonmissile penetrating injuries are presented. This case demonstrates the importance of a thorough physical examination and the use of neurodiagnostic imaging in an inebriated, uncooperative patient with neurological dysfunction. CLINICAL PRESENTATION: The patient presented with quadriparesis confounded by cocaine intoxication. A physical examination revealed only a small punctate lesion in the posterior occipital region. INTERVENTION: After detection of the foreign body, the patient underwent immediate surgical exploration and removal of the object. The dura was repaired primarily, and the patient was maintained on intravenous antibiotics for 7 days. CONCLUSION: With physical therapy, the patient was walking with assistance at 2 weeks postsurgery. Upper extremity strength, especially intrinsic hand movement, was most severely affected. At 10 months' follow-up, the patient's only deficits were mild intrinsic hand weakness and incoordination with fine finger movements. Immediate surgical exploration is indicated for patients with retained fragments and progressive neurological dysfunction.

Adult↗
PubMed1996

The surgical treatment of metastatic spinal tumors within the intradural extramedullary compartment.

The authors retrospectively reviewed the surgical outcomes in 10 cases of symptomatic intradural extramedullary spinal metastases of nonneurogenic origin because the collective experience in treating this rare manifestation of systemic cancer is limited. Pain and weakness were the presenting complaints in 70% of the patients and sensory changes were found in all cases. Cytological tests on one specimen of cerebrospinal fluid (CSF) from each of seven patients showed malignant cells in two cases. Gadolinium contrast-enhanced biplanar magnetic resonance (MR) imaging was effective in localizing the lesion and showed evidence of leptomeningeal carcinomatosis in two cases; myelography showed leptomeningeal carcinomatosis in one case and erroneously identified the lesion as intramedullary in the other. Eight of 10 cases had antecedent intracranial metastatic foci with the interval from presentation of the intracranial lesion to appearance of the spinal disease ranging from 3 to 51 months. The majority of the spinal lesions occurred in the thoracolumbar area. The most frequent histological type was adenocarcinoma and the most frequent source was the lung. In all cases laminectomies, intradural exploration, and biopsy or subtotal excision aided by microscopy and ultrasonography were performed. Results of surgical decompression were poor with only 30% of the patients showing improvement, at a 20% risk of perioperative mortality and a 60% risk of morbidity. Plans for surgical intervention in patients with intradural extramedullary metastases from a distant noneurogenic source should be weighed against the high association with intracranial lesions, overall poor prognosis, and modest symptomatic results of decompression. Comprehensive evaluation including multiple specimens of CSF for cytology and contrast-enhanced MR imaging should be undertaken to exclude patients with diffuse leptomeningeal involvement, who should be treated by means other than surgery.

Adult↗