© Borgis - New Medicine 3/2008, s. 77-79
*Lechosław P. Chmielik, Anna Chmielik1, Jolanta Jadczyszyn, Magdalena Żabicka1, Mieczysław Chmielik
USEFULNESS OF INTRAOPERATIVE NAVIGATION IN SINUS OPERATIONS ON CHILDREN
Department of Paediatric ENT, Warsaw Medical University, Poland
Head of Department: Prof. Mieczysław Chmielik, MD, PhD
1Medical Radiology Unit, Military Medical Institute, Warsaw, Poland
Head of Radiology Unit: Ass. Prof. Romana Bogusławska, MD
Summary
Introduction: Progress in medicine depends largely on development in the fields of engineering and computer science. It the nineteen seventies, the invention of computed tomography allowed the possibility of identifying previously unknown pathological situations.
Among actions designed to reduce the risk of complications during PESS, we must include appropriate training for the surgeon and the application of instrumentation adapted specially for children. In the very difficult operative field found in children intraoperative navigation facilitates intervention. The navigation can operate on the optical or electromagnetic principle, and is mainly applied in neurosurgery and ENT.
Aim: To analyse the value of intraoperative navigation during PESS.
Material and method: Ten children underwent PESS with the use of intraoperative navigation in the Paediatric ENT Department of the Warsaw Medical University.
Results: All parameters significantly improved postoperatively compared to the preoperative values. During measurements made in 95% the error of the measurement was 0 mm. In 5% the error of the measurement did not exceed 2 mm. The operative strategy was changed by the introduction of navigation.
Conclusions: 1. Intraoperative navigation is a method considerably facilitating the sense of direction in the operative field. 2. Applying it can reduce the risk of post-operative complications appearing. 3. Error of the measurement reaching 2 mm is a limitation.
INTRODUCTION
Progress in medicine depends largely on developments in the fields of engineering and computer science. It the nineteen seventies, the invention of computed tomography allowed the possibility of identifying previously unknown pathological situations. This resulted in the introduction of new therapeutic methods such as endoscopic operation techniques.
However, every medical action carries the risk of complications. Among actions designed to reduce the risk of complications during PESS, we must include appropriate training for the surgeon and the application of instrumentation adapted specially for children. In the very difficult operative field found in children intraoperative navigation facilitates intervention. The navigation can operate on the optical or electromagnetic principle, and is mainly applied in neurosurgery, ENT and maxillofacial surgery (1, 2, 3, 4, 6, 7, 8, 9, 10, 11).
aim
To analyse the value of intraoperative navigation during PESS.
MATERIAL
Ten children underwent PESS with the use of intraoperative navigation in the Paediatric ENT Department of the Warsaw Medical University.
METHOD
Children were qualified for paranasal sinus surgery due to chronic inflammation. They had a CT examination directly before the operation. Spiral computed tomography with secondary multilevel reconstruction was used, with slice thickness of 0.625 mm, at the Medical Radiology Unit of the Military Medical Institute in Warsaw. The examination results were taken on CD for installation in FUSION ENT Navigation (electromagnetic navigation) equipment (Medtronic). During the operation the accuracy of the navigation in locating anatomical structures and identifying pathological changes was assessed.
RESULTS
The operation was concerned with removing pathological changes and extending ostium-ductal complexes. In one child additional surgery was done as a double-sided operation of the sphenoid sinus, in two children on the ethmoid sinus opening. One case was a reoperation of the maxillary sinuses. Stricture of the natural ostium of the maxillary sinuses was found in all ten cases, inflammatory changes of the mucous membrane in seven children (in three swellings, in four widened blood vessels of the mucous membrane), one child had a cyst, and in three patients polyps were found. During measurements in 95% the error of the measurement was 0 mm.
In 5% the error of the measurement did not exceed 2 mm and it reduced after correcting the location of the navigating tool.
DISCUSSION
The literature shows reports of problems encountered by surgeons in functional endoscopic sinus surgery. The basic knowledge which the operator must have includes an outstanding acquaintance of anatomy and the appropriate preoperative practice. One of the more frequent problems during PESS is bleeding. This can result in loss of the spatial image in the operative field. The lack of the sense of direction in the operative field can cause the appearance of complications or need to stop the surgery (2, 5, 6, 11).
Taking the computed tomography sinus examination directly before PESS is one of the elements in reducing the risk of appearance of complications. For that reason surgery which is based on the out-of-date CT examination does not consider all changes, since the pathological process can still act and destroy neighbouring structures. In such a case after removing pathological changes the surgeon unexpectedly can, without knowledge about this fact, be inside an important anatomical structure. In the operative field navigation involves use of a device facilitating the sense of direction during the operation. Thanks to analysis of the preoperative computed tomography or the magnetic resonance scans, the system locates the tool in the operative field. The tool is identified by the location in the horizontal coronal, axial planes, and in 3D reconstruction (photo 1). The error of the measurement does not exceed 2 mm and decreases as the CT slices become thinner (acceptable are slices from 0.5 to 2.7 mm). The distance of the tool from the electromagnet being the point of reference is the second factor playing a role in reducing the error of the measurement. So, slices of 0.625 mm used in sinus CT and the field of size 40 x 40 cm in which the tools were applied gave a small error of the measurement not exceeding 2 mm (2, 5, 7, 11).
Photo 1. Identification of maxillar´s polyps.
CONCLUSIONS
1. Intraoperative navigation is a method considerably facilitating the sense of direction in the operative field.
2. Applying it can reduce the risk of post-operative complications appearing.
3. Error of the measurement reaching 2 mm is a limitation.
Piśmiennictwo
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