Article
The scintigraphic examination of swallowing: an alternative method for the screening of a suspected fistula?
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Published: | July 23, 2012 |
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Introduction: After laryngectomy or endoscopic surgery for a Zenker diverticulum it is common practice to perform postoperatively a modified barium swallow with water soluble contrast media in order to rule out a fistula or an extravasation. The exposure of the patient to radiation corresponds to approximately 15 chest radiographs. The oropharyngooesophagoscintigraphy (OPOS) is a nuclear medical examination with a low radiation exposure. In our study we examined whether the OPOS can replace the modified barium swallow as a screening method in the postoperative setting.
Methods: 15 laryngectomized patients and 6 patients which underwent endoscopic surgery for a Zenker diverticulum had postoperatively an OPOS examination. In the first group of patients the radioactivity at the tracheal cannula was measured after oral ingestion of radioactive material. In the second group the course of the radioactive material in the upper aerodigestive tract was recorded and a late image was taken, scanning for extravasation in the mediastinum. If the test result was positive, it was confirmed with a modified barium swallow.
Results: The OPOS showed postoperatively no extravasation in all patients with a Zenker's diverticulum. In 3 of the 15 laryngectomized patients highly increased radioactivity (compared to the background radioactivity level) was registered at the tracheal cannula, in three other patients only moderately elevated levels were shown. The presence of a fistula was confirmed only in the first three cases by a modified barium swallow.
Conclusions: The OPOS has compared to the modified barium swallow – the gold standard examination – a sensitivity of 100% and a specificity of 83%. The low specificity is due to its hypersensitivity, it can register extravasations of only a few molecules, which are without clinical relevance. The OPOS is thus equivalent to the modified barium swallow if cut-off values are set. The exposure to radiation is smaller by a factor of 10.