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Biomedical subjects

F W Poon

Publications and source records attributed to F W Poon.

9 recordsLinked to original sources
PubMed1992

Combined nuclear and digital subtraction contrast arthrography in painful knee prosthesis.

The evaluation of a painful knee prosthesis remains a difficult problem for both orthopaedic surgeons and radiologists. We have compared digital subtraction arthrography with nuclear arthrography in 7 patients with a painful knee prosthesis. Three patients showed a loose tibial component, demonstrated by both digital subtraction and nuclear arthrography. All 3 underwent revision of their prosthesis. One patient had an equivocal digital subtraction arthrogram and negative nuclear arthrogram, while both studies were negative in the 3 remaining patients. Nuclear arthrography is a simple procedure and can provide useful additional information when combined with digital subtraction arthrography.

Aged↗
PubMed1992

Videoproctography in selecting patients with constipation for colectomy.

The results of colectomy for constipation based only on evidence of delayed colonic markers have been disappointing. The operation may fail because these patients are unable to evacuate the rectum owing to outlet obstruction. In the present study, we have used a combination of videoproctography and transit marker studies in an attempt to predict patients who will have a favorable outcome after colectomy by excluding patients with outlet obstruction. Videoproctography was performed in 228 patients referred for consideration of surgery for constipation. Only 111 (38 percent) had a normal proctogram with complete evacuation of liquid barium. Of these 111 patients, 21 (19 percent) had delayed colonic marker studies. Colectomy and ileorectal anastomosis were performed in 18 of these 21 patients; two years later, 16 were symptom free, with a median daily bowel frequency of four (range, two to six). The remaining two patients failed to respond to surgery. These data suggest that true idiopathic, slow-transit constipation is uncommon, but, when identified on the basis of delayed markers and the ability to expel liquid on proctography, an excellent result can be anticipated from colectomy and ileorectal anastomosis.

Adolescent↗
PubMed1992

Vertebral metastases and an equivocal bone scan: value of magnetic resonance imaging.

To assess the value of magnetic resonance imaging (MRI) in the investigation of patients with suspected but nonproven vertebral metastases 45 consecutive patients referred in a 6 month period with known primary malignancy and back pain in whom an isotope bone scan was reported as equivocal were studied. All patients had abnormal isotope uptake localized to the spine. Twelve patients were shown to have bony metastases on plain X-ray. In the remainder, where X-rays showed normal or benign appearance, MRI of the spine was offered. Twenty-four patients underwent MRI examination which showed vertebral metastases in 11 cases. Magnetic resonance imaging is shown to be a useful, noninvasive, complementary investigation for evaluation of patients known to have malignant disease and suspected of having vertebral metastases on bone scintigraphy.

Back Pain↗
PubMed1992

A prospective randomized study of abdominal rectopexy with and without sigmoidectomy in rectal prolapse.

Eighteen patients with full-thickness prolapse of the rectum were randomized to rectopexy alone (group 1) or with sigmoidectomy (group 2). Three months postoperatively, seven patients in group 1 and two in group 2 complained of severe constipation. One patient in group 1 and three patients in group 2 remained incontinent. The results of colonic marker studies showed a significant increase in the number of markers at day 5 for those in group 1 (preoperative, 7.7 +/- 2.6; postoperative, 14.6 +/- 2.2; t test, p less than 00.1) but no significant increase in group 2 (preoperative, 4.6 +/- 2.2; postoperative 6.8 +/- 2.3; t test, p less than 0.01). No significant changes or differences between the groups were seen in the anorectal angle on videoproctogram. The results of anorectal physiologic studies done postoperatively showed no differences between the groups in maximum resting pressure, sphincter length or saline solution infusion test; however, the patients in group 1 had a significantly greater rectal compliance (group 1, 0.24 +/- 0.02 millimeters mercury per milliliter; group 2, 0.1 +/- 0.02 millimeters mercury per milliliter; p less than 00.1). This may occur because the redundant loop of sigmoid colon causes hold-up of intestinal content and kinking at the junction between the sigmoid colon and the rectum.

Aged↗
PubMed1991

Technical report: evacuating proctography--a simplified technique.

We describe a prospective study of 63 patients with proctological symptoms, comparing the radiological findings when performing evaluating proctography in both the sitting and left lateral positions. We found that although the left lateral method was slightly less sensitive, the abnormalities missed represented only minor early changes and were of no clinical significance. We conclude that the technique we have described could be adopted easily as a screening procedure for patients with unexplained anorectal symptoms.

Adolescent↗