Communication issue - What should the radiologist report before functional endoscopic sinus surgery

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1 Communication issue - What should the radiologist report before functional endoscopic sinus surgery Poster No.: C-0509 Congress: ECR 2015 Type: Educational Exhibit Authors: A. M. Dobra 1, C. A. Badiu 1, A. Balint 2, I. Barsan 1, M. Buruian 1, G. Keywords: DOI: Muhlfay 1 ; 1 Targu Mures/RO, 2 Bistrita/RO Ear / Nose / Throat, Anatomy, CT, Diagnostic procedure, Surgery, Normal variants, Education and training /ecr2015/C-0509 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 13

2 Learning objectives The aim of this poster is to improve communication between radiologist and ENT surgeon, by presenting a systematic approach in the computed tomography evaluation of paranasal sinuses prior to functional endoscopic sinus surgery. Background FUNCTIONAL ENDOSCOPIC SINUS SURGERY (FESS) is a minimally-invasive surgical procedure which aims to restore normal sinus drainage and ventilation. It involves removal of diseased mucosa and bone in order to reestablish the normal flow of mucosal secretions. INDICATIONS for FESS include: - chronic sinusitis refractory to medical treatment - recurrent sinusitis - nasal polyposis - sinus mucoceles - selected tumors excision - cerebrospinal fluid leak closure - orbital decompression - optic nerve decompression - foreign body removal COMPLICATIONS associated with FESS vary from minor and temporary to permanent. Anatomical variants predispose certain structures to injury during FESS. Possible complications include: - hemorrhage - recurrent inflammatory disease - synechiae formation - orbital injury Page 2 of 13

3 - diplopia - orbital hematoma - nasolacrimal duct injury - CSF leak - intracranial complications Today, MULTIDETECTOR COMPUTED TOMOGRAPHY is the reference standard, mandatory in the preoperative evaluation of paranasal sinuses. Patient preparation prior to paranasal sinus MDCT evaluation is very important. If signs of acute sinusitis are present, mucosal abnormalities and inflammatory fluids will distort the anatomy encountered by ENT surgeon after resolution of acute inflammatory phase. Imaging of paranasal sinuses involves scanning in axial plane. From the raw data additional MPR images are obtained in coronal and sagittal planes, using both bone and soft tissue windows. Coronal plane is preferred because it simulates the plane seen by the ENT surgeon. In the majority of patients evaluated for sinusitis only unenhanced scans are performed but if a neoplastic process is suspected intravenous contrast is given. RADIOLOGIC REPORT should include information about 4 key points: - the pathological transformation of the normal anatomy - anatomical variants if they are present - evaluation of critical variants - condition of soft tissues of brain, neck and orbits Findings and procedure details Using a 64-slice CT scanner we will present a systematic approach that will guide radiologist to give the best clues to the surgeon before a functional endoscopic sinus surgery. Page 3 of 13

4 Based on the key points that have to be included in the radiological report and the structures encountered in FESS technique we will make a stepwise presentation. A systematic approach is required in interpreting MDCT scans. Reading the scans has to be organized from top to bottom (on axial plane) and from anterior to posterior (on coronal plane) in order to analyze all the structures. In order to offer to the ENT surgeon a preoperative anatomical road-map, the radiologist has to know the NORMAL ANATOMY. It is also mandatory for the radiologst to identify ANATOMICAL VARIANTS and their implications. These can have intraoperative consequences affecting operative techniques or postoperative effects predisposing to possible complications. NASAL SEPTUM - one of the first structures encountered, intraoperatively, on entering nasal cavity - forms the medial border of nasal cavity and has two parts: o soft mobile septum (anterior) o hard portion (posterior) - extends to the perpendicular plate of the ethmoid bone postero-superiorly and the vomer postero-inferiorly [Figure 1] SEPTAL DEVIATION may cause nasal cavity obstruction and may limit endoscopic visualization and access during procedure. Septoplasty in conjunctions with FESS may be needed. [Figure 2] INFERIOR TURBINATE - first structure encountered intraoperatively, beside nasal septum - extends along the inferior nasal wall posteriorly towards the nasopharynx [Figure 1] - the nasolacrimal duct opens in the posterior part of inferior meatus Edematous and enlarged inferior turbinate may be present in patients with allergic component in their disease. Turbinate reduction in conjunction with FESS may be benefic. Page 4 of 13

5 MIDDLE TURBINATE - next structure encountered as the endoscope is advanced through nasal cavity [Figure 1] - it has three anatomical parts: o anterior third runs vertically from posterior to anterior; superior it is attached at the lamina cribrosa of the cribriform plate to the skull base o middle third inserts laterally on lamina papyracea o posterior third becomes horizontal and attaches to the lateral nasal wall - the cranial part referred to as BASAL LAMELLA divides the anterior and posterior ethmoid air cells [Figure 3] - represents the landmark for access to the posterior ethmoidal air cells CONCHA BULLOSA represents pneumatized middle turbinate and is a relatively common anatomical variant. It may cause obstruction of ethmoid infundibulum. [Figure 4] PARADOXICAL MIDDLE TURBINATE appears when the convexity of the bone is directed laterally (unlike the normal situation when the convexity of middle turbinate is deviated medially). This may lead to obstruction of middle meatus. UNCINATE PROCESS - the next key structure encountered in FESS - it is a L-shaped bone of the lateral nasal wall, part of the ethmoid bone - it runs along the inferior margin of the ethmoid infundibulum or hiatus semilunaris, which is the location of osteomeatal complex (OMC), where the ostium of the maxillary sinus opens [Figure 5] - it has a complex attachment: o anteriorly - to nasolacrimal apparatus o inferiorly - to ethmoidal process of the inferior turbinate o posteriorly - it has a free margin o superiorly - variable to the middle turbinate, lamina papyracea or skull base Page 5 of 13

6 - surgically, the uncinate must be removed in order to gain access to the ethmoid infundibulum; maxillary sinus ostium can be visualized and enlarged by a maxillary antrostomy Uncinate process may be deviated laterally causing narrowing of the hiatus semilunaris and infundibulum. If it is too laterally, there is a risk of entry into the orbit, and subsequent risk of loss of vision. MAXILLARY SINUS - with an approximate volume of 15 ml, it is bordered by: o superiorly: inferior orbital wall o medially: lateral nasal wall o inferiorly: alveolar portion of maxillary bone [Figure 1] ETHMOID SINUS - consists of a variable number of air cells (7-15) - it is bounded: o laterally: lamina papyracea o superiorly: the floor of the anterior cranial fossa - the basal lamella of the middle turbinate separates the anterior ethmoid air cells from the posterior ethmoid air cells [Figure 3] - anterior ethmoid cells drain to the middle meatus and posterior ethmoid cells drain into the superior meatus Due to the location and close relationship with the orbit and anterior skull base, intraoperative there is a risk of penetration superiorly into the floor of anterior cranial fossa or laterally through lamina papyracea. ETHMOID BULLA - reliable surgical landmark in FESS - it is the largest and most constant anterior ethmoid air cell [Figure 1] Page 6 of 13

7 - located on the lateral wall of the middle meatus, it is bounded inferiorly by the ethmoid infundibulum into which it drains AGGER NASI CELL is the most anterior ethmoid air cell, present anterior to the attachment of middle turbinate and frontal recess. They are consistent findings and if they are large they may cause medial displacement of the middle turbinate causing narrowing of the frontal recesess. HALLER CELL represents ethmoidal air cells located into the roof of maxillary sinus or into the floor of the orbit. If they are large they may obstruct maxillary sinus ostium. ONODI CELL is the most posterior ethmoid air cell which extends superiorly and laterally to the sphenoid sinus lying medial to the optic nerve. Intraoperative entering sphenoid sinus through what is thought to be the most posterior ethmoid cell rather than an Onodi cell may cause damage to the optic nerve and internal carotid artery. The radiologist also has to identify and evaluate the following CRITICAL VARIANTS: LAMINA PAPYRACEA - congenital or posttraumatic dehiscence of the lamina papyracea has to be identified because it provides direct route for sinus surgery instruments intro the orbit and increases the risk of orbital content damage [Figure 6] CRIBRIFORM PLATE - the lateral lamella is the thinnest part of the cribriform plate and it is at risk of fracture during FESS - anatomic variations as olfactory fossae depth or asymmetry may increase the risks of intracranial penetration and anterior or posterior ethmoidal artery damage [Figure 7] - Keros classification describes the position of the cribriform plate relative to the fovea ethmoidalis: o Keros I: 1-3mm o Keros II: 3-7mm o Keros III: 7-16mm SPHENOID SINUS Page 7 of 13

8 - the most posterior of the sinuses [Figure 8] - it is related to important, potentially hazardous structures including: o internal carotid artery: typically the most postero-lateral structure within sphenoid sinus o optic nerve: produces a antero-posterior indentation in the roof of the sphenoid Description of PATHOLOGICAL TRANSFORMATIONS should include the extent of sinus opacification and opacification of sinus drainage pathways. It is important to delimitate an acute sinusitis from chronic conditions. CT findings in acute sinusitis include sinus opacification, air-fluid levels, and thickened localized mucosa. In chronic sinusitis suggestive imaging findings include mucosal thickening, opacified air cells, bony remodeling. Bony erosion may occur in cases associated with polyps and mucoceles. Bone destruction raises the suspicion of tumors or granulomatous disease processes. Polyps appear as rounded masses and may cause mass effect, obstruction and secondary infections. Images of SURROUNDING TISSUES should be obtained using soft tissue windows, in order to detect and evaluate the extrasinus extension of disease in the orbit, neck and brain. Pathologic findings may lead to contrast administration and further investigations. Images for this section: Page 8 of 13

9 Fig. 1: Coronal CT image shows normal anatomy: nasal septum (NS), inferior turbinate (IT), middle turbinate (MD), ethmoid bulla (BE) and maxillary sinus (Max). References: Department of Radiology, Emergency Clinical County Hospital of Targu Mures. Fig. 2: Coronal CT image shows nasal septum deviation from right to left. References: Department of Radiology, Emergency Clinical County Hospital of Targu Mures. Fig. 3: Axial CT image shows basal lamella (arrow) that separates the anterior ethmoid air cells (AnE) from the posterior ethmoid air cells (PoE). Note the nasolacrimal duct (circle). References: Department of Radiology, Emergency Clinical County Hospital of Targu Mures. Page 9 of 13

10 Fig. 4: Coronal CT image shows an anatomic variant - concha bullosa representing pneumatized middle turbinate. References: Department of Radiology, Emergency Clinical County Hospital of Targu Mures. Fig. 5: Coronal CT image shows normal aspect of the osteomeatal complex (OMC) which consists of four structures: hiatus semilunaris (circle), uncinate process (arrow), Page 10 of 13

11 infundibulum (line) and maxillary sinus otarstium (star). References: Department of Radiology, Emergency Clinical County Hospital of Targu Mures. Fig. 6: Coronal CT image shows lamina papyracea (LP) one of the structures that can be potentially hazardous during FESS, especially when it is dehiscent. References: Department of Radiology, Emergency Clinical County Hospital of Targu Mures. Page 11 of 13

12 Fig. 7: Coronal CT image shows fovea ethmoidalis (FE), crista galli (CG) and another structure that can be critical during FESS - the cribriform plate (CP). According to the depth of the olfactory fossa (line) in this case the CP belongs to Keros II. References: Department of Radiology, Emergency Clinical County Hospital of Targu Mures. Fig. 8: Axial CT image shows sphenoidal ostium (arrow) and sphenoid sinus (SS), one of the potentially hazardous structures during FESS, because of its close relationship with internal carotid artery and optic nerve. References: Department of Radiology, Emergency Clinical County Hospital of Targu Mures. Page 12 of 13

13 Conclusion In order to decrease possible intraoperative and postoperative complications, the radiologist has to give precise clues to the surgeon. The preoperative report should include not only details about the existing pathology but also information about anatomy, including: anatomical variants, critical variants and surrounding tissues. An accurate approach is compulsory in the preoperative imaging evaluation but the postoperative feedback from the ENT surgeon to the radiologist can be an important step for better results in the future. Personal information References 1. Jenny K, James D, Christopher L, et al. Multiplanar Sinus CT: A Systematic Approach to Imaging Before Functional Endoscopic Sinus Surgery. AJR June; 194(6) 2. Cashman E, MacMahon P, Smyth D. Computed tomography scans of paranasal sinuses before functional endoscopic sinus surgery. World J Radiol August; 3(8): Vaid S, Vaid N, Rawat S, et al. An imaging checklist for pre-fess CT: framing a surgical relevant report. Clin Radiol May; 66(5): Uma D, Bhawna D. Pictorial essay:anatomical variations of paranasal sinuses on multidetector computed tomography - how does it help FESS surgeons? Indian J Radiol Imaging Oct-Dec; 22(4): Ankit P, Lanny G, Francisco T, et al. Functional Endoscopic Sinus Surgery. Medscape Chong V, Fan Y, Lau D, et al. Functional Endoscopic Sinus surgery (FESS): What Radiologists Need to Know. Clin Radiol. 1998; 53: Kazakayasi M, Karadenis Y, Arikan O. Anatomic variations of the sphenoid sinus on computed tomography. Rhinology June; 43(2): Page 13 of 13