Feasibility of balloon sinuplasty in patients with chronic rhinosinusitis: the Graz experience

BACKGROUND

Balloon sinuplasty (BSP) is a catheter-based technique to dilate sinus ostia and drainage pathways to create ventilation and drainage. The aim of this study was to evaluate the feasibility of BSP in routine treatment of patients suffering from chronic rhinosinusitis (CRS).

METHODOLOGY

Patients with CRS refractory to medical therapy who had been scheduled for endoscopic sinus surgery between 2009 and 2011 were included in this study.

RESULTS

Forty-five consecutive patients were included in this study, in whom 112 sinuses were approached by BSP. Of the 112 sinuses, 68 (60%) were planned as a "Balloon-Only" procedure and 44 (40%) were planned as a "Hybrid" procedure. Of the 68 sinuses in the "Balloon-Only" group, in 44 sinuses BSP failed, equating to a failure rate of 65%. Forty-four sinuses were planned for "Hybrid" procedures. In 29 of these sinuses BSP failed, giving a failure rate of 66%.

CONCLUSION

According to literature, BSP can be a useful adjunct technique to standard FESS. In our experience, however, a failure rate of 65% for "Balloon-Only" and of 66% for "Hybrid" procedures occurred, which was regarded as unacceptable by the study group. Therefore, the study initially scheduled for 200 consecutive patients, was abandoned.

Cholesterol granulomas of the petrous apex; endonasal endoscopic approach

OBJECTIVE

Cholesterol granulomas are benign lesions that sometimes occur on the petrous apex (PA). We report our experience using an endoscopic endonasal approach to remove PA cholesterol granulomas.

MATERIAL AND METHODS

A retrospective patient chart analysis was conducted at a tertiary care university hospital.

RESULTS

Four patients (3 females, 1 male) were included in this study. Patients' ages ranged from 27 to 78 years. Computed tomography (CT) and magnetic resonance imaging (MRI) for diagnosis and computer-assisted navigation were performed. The most common symptom was abducens nerve palsy. The largest granuloma measured 5 x 2 cm and was located on the left side. An endoscopic endonasal approach was chosen and navigation was applied (3/4 patients) to identify the optimal area for opening the granuloma. No complications occurred, and patients were free from recurrence during the follow-up period.

CONCLUSION

The endoscopic endonasal approach to PA cholesterol granulomas is feasible and safe. Intra-operative navigation is recommended to identify the position of the internal carotid artery and determine the safest area for opening the granuloma without damaging the artery. Another advantage of this approach is an easier follow-up through diagnostic nasal endoscopy.

The influence of the heel effect in cone-beam computed tomography: artifacts in standard and novel geometries and their correction

For decades, the heel effect has been known to cause an angular dependence of the emitted spectrum of an x-ray tube. In radiography, artifacts were observed and attributed to the heel effect. However, no problems due to the heel effect were discerned in multi-slice computed tomography (MSCT) so far. With flat-detector CT (FDCT), involving larger cone angles and different system geometries, the heel effect might cause new artifacts. These artifacts were analyzed in this paper for system geometries different from the ones widely used nowadays. Simulations and measurements were performed. Simulations included symmetric as well as asymmetric detector layouts and different x-ray tube orientations with respect to the detector plane. The measurements were performed on a micro-CT system in an asymmetric detector layout. Furthermore, an analytical correction scheme is proposed to overcome heel effect artifacts. It was shown that the type of artifact greatly depends on the orientation of the x-ray tube and also on the type of detector alignment (i.e. symmetric or different types of asymmetric alignment). Certain combinations exhibited almost no significant artifact while others greatly influenced the quality of the reconstructed images. The proposed correction scheme showed good results that were further improved when also applying a scatter correction. When designing CT systems, care should be taken when placing the tube and the detector. Orientation of the x-ray tube like in most MSCT systems seems advisable in asymmetric detector layouts. However, a different type of tube orientation can be overcome with suitable correction schemes.

New measures of multimodality for the detection of a ghost stochastic resonance

Large-amplitude (10-15 K) millennial-duration warming events, the Dansgaard-Oeschger (DO) events, repeatedly occurred in the North Atlantic region during ice ages. So far, the trigger of these events is not known. To explain their recurrence pattern, a ghost stochastic resonance (GSR) scenario has been suggested, i.e., a dynamical scenario in which the events represent the subharmonic response to centennial-scale solar forcing plus noise. According to this hypothesis a multimodal phase distribution of the events is expected, which should be tested on the basis of climate records by means of time series analysis. A major obstacle in these tests, however, is the need of a statistical measure of regularity that can distinguish between a random occurrence of DO events and a GSR scenario. Here we construct and compare three new measures of phase multimodality. In a Monte Carlo simulation with a simple conceptual model of DO events we simulate probability distributions of the measures under both scenarios for realizations of only 11 DO events. Based on these distributions we find that our measures are able to distinguish between a random occurrence and a GSR scenario. We further apply our measures to analyze the recurrence pattern of the last 11 DO events in the North Greenland Ice Core Project deep ice core from Greenland.