Image guided endoscopic sinus surgery

Rationale: Paranasal sinus malignant neoplasms constitute a group of tumours that present often at an advanced stage. Their surgical management can therefore be challenging, regarding also their proximity to significant structures like the orbit and the brain. Particularly, cases with extensive disease and recurrent tumours are often incompletely resected and local treatment failure is commonly observed.

Objective: The primary objective of this study is to assess the feasibility of utilizing intraoperative cone-beam CT (CBCT) to verify the intended excision volume of paranasal sinus malignant tumours. CBCT images will be matched with a preoperative planning of the resection volume on the preoperative MRI or CT. This study will be the first step before conducting a randomised control study that will evaluate the efficacy of CBCT verified resection.

Study design: Exploratory pilot study.

Study population: A total number of 6 patients, above 18 years old, with paranasal sinus cancer suitable for management with endoscopic sinus surgery will be included. All patients will undergo a pre-operative MRI scan of the maxilla for the evaluation of the local extent of the tumour. In this MRI, the tumour volume that is indented to be resected will be segmented.

The patients will be studied in two distinct phases:

1. Three patients will undergo the standard endoscopic sinus surgery and intra-operative control with CBCT, however without any further resection

2. Three patients that will undergo the endoscopic sinus surgery and intra-operative CBCT and additional excision, in case that residual tumour is observed based on the preoperative MR resection planning.

Main study parameters/endpoints: The main parameter of this pilot study is the technical success of implementing CBCT during endoscopic sinus surgery as an additional tool for the control of the resection. Operating time will be recorded and the mean duration of the procedure will be calculated. Assessment of the possible residual tumour volume will be also performed based on the intraoperative CBCT, as well as comparison to the planned resection volume as calculated in the preoperative imaging planning. The quality of CBCT and MRI scan matching will also be evaluated. No correlation to clinicopathological parameters will be established in this study.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The burden for the individual patient is the extra operating time it takes (approximately 15 minutes for each CBCT scan). The only extra risk involves the additional exposure to ionizing radiation, although the dose of a CBCT scan is significantly lower than that of a conventional CT of the head (approximately 1/3 to 1/6 of the dose). Endoscopic sinus surgery itself is a well-established, routine treatment modality used as a standard procedure in patients with paranasal sinus malignancy. The potential benefits for the patients are also considerable. Till now the surgeon’s experience in recognizing potential residual tumour is the main factor for a successful endoscopic sinus surgery. The intra-operative use of CBCT can potentially verify the complete tumour resection, minimizing the risk of residual tumor and local treatment failure.

Intraoperative verification of paranasal sinus malignancy resection with cone-beam computed tomography will lead to a higher rate of radical resection

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