FLEX January 2024

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Otolaryngology–Head and Neck Surgery 164(2)

Figure1. Subtotal resection (type 1, T1-weighed postcontrast). Large paraganglioma centered in the left jugular foramen (A). Tumor com ponent within the internal jugular vein (B). Postoperative imaging showing resection of most of the lesion (C).

predictors of successful local control using volumetric analy sis as well as preservation of swallowing and voice function.

these cases, disease in the jugular bulb was not resected ( Figure 3A-C ).

Radiation Linear accelerator-based stereotactic radiosurgery (SRS) or intensity-modulated radiotherapy (IMRT) was used either in the adjuvant or salvage settings after multidisciplinary review. All patients received pretreatment contrast-enhanced thin-slice magnetic resonance imaging or magnetic resonance angiogra phy, which was subsequently co-registered with high-resolution computed tomography (CT) for radiation treatment–planning purposes and for contour delineation. Brainlab iPlan (Brainlab AG, Munich, Germany) or Eclipse software was used for dosi metric planning and evaluation. Earlier patients were treated with frame-based immobilization using a Clinac 4 (Varian, Palo Alto, CA), while more recent patients were treated with mask-based (aquaplast) immobilization on a Novalis TX linear accelerator (Varian). ExacTrac orthogonal imaging was used to confirm proper patient alignment during treatment (Brainlab AG, Munich Germany). Volumetric Analysis Pre- and posttreatment enhanced CT and magnetic resonance studies were used to calculate tumor volumes (cm 3 ) and linear dimensions using semiautomated manual tracing of tumor margins using syngo.via postprocessing, thin-client software (Siemens, Erlangen, Germany, version VB30, MM Reading Workflow) by an experienced neuroradiologist (J.M.A.). For volume measurements, the tumor was segmen ted using the volume of interest freehand manual tracing tool in the optimal axial or coronal plane, and the volume was calculated by the software ( Figure 4A , B ). Jugular PGL have complex geometrical shapes and can have intraluminal disease in the venous sinus and jugular bulb ( Figure 4C ). For linear dimensions, the largest dimension in the axial plane was measured using a linear caliper, followed by the largest perpendicular dimension on the same image slice. Similarly, the largest craniocaudal dimension was measured in the coronal plane.

Methods After institutional review board approval (Vanderbilt University Medical Center, IRB 181441), retrospective chart review was carried out to extract data related to patient, disease, and treatment factors. Patient variables included age, gender, laterality, family history, synchronous PGL, prior surgical or radiation treatment, and presentation. Tumor characteristics and treatment records were reviewed including staging (Glasscock-Jackson), 1 preoperative embolization, surgical approach, extent of resection (EOR), adjuvant or salvage radiation, and final tumor control. Facial nerve function was documented using the House Brackmann (HB) grade. Lower cranial nerves (CN IX, X, XI and XII) were assessed at the time of initial presentation and after any intervention. Treatment-related complications (dys phagia requiring percutaneous gastrostomy tube [PEG], need for medialization laryngoplasty for new-onset CN X dys function, cerebrospinal fluid leak, or surgical site infection) were documented. Surgical Details Microsurgical resection was performed according to the stage of disease. In advanced disease, patients underwent a combined approach by neurotology and head and neck surgi cal teams via an infratemporal fossa type A (IFTA) approach with or without facial nerve mobilization. Three types of STR were performed. Extended STR (type 1) was used when the aim was to remove the middle ear, mastoid, cervi cal, and infratemporal fossa component while preserving the medial wall of the jugular bulb and pars nervosa ( Figure 1A-C ). Posterior fossa craniotomy-based STR (type 2) was used when the main objective was to decrease tumor burden in the posterior cranial fossa and decompress the brainstem ( Figure 2A-C ). Limited STR (type 3) was employed when middle ear and mastoid disease was removed using an otolo gic approach without any concomitant cervical approach. In