FLEX January 2024

10976817, 2021, 2, Downloaded from https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599820938660 by UNIVERSITY OF MINNESOTA 170 WILSON LIBRARY, Wiley Online Library on [24/09/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License

Manzoor et al

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lumbar drain. Two patients developed surgical site infections (5%). There were no cases of meningitis, intracranial bleed ing, or mortality. Discussion Jugular PGL are the most common tumors involving the jugular foramen, and management requires a complex recon ciliation of multiple patient and disease variables. 1,3 While GTR has historically advocated for complete resection of tumor, its resultant morbidity has given way to more conser vative approaches for management of jugular PGL. 1,6-9 STR has yielded a lower incidence of new-onset LCN. In cases of remnant growth or recurrence, salvage radiation can be used for optimal control of tumor, with resultant excellent local control in most patients. 8-10 STR can be tailored to the extent of disease and patient goals. Extended STR is usually employed for high-volume disease with a significant cervical and infratemporal fossa component. The principle of these resections is to remove the disease lateral to the medial wall of the jugular bulb while preserving lower cranial nerves ( Figure 1A-C ). Limited STR is usually employed in the removal of the middle ear and mastoid tumor component or for the targeted removal of posterior fossa tumor in cases of significant intra cranial extension with brainstem compression ( Figures 2 and 3 ). Various lateral and posterolateral skull base approaches can be used for management of the intracranial component. In the presence of functional lower cranial nerves, utmost care is taken to preserve the cisternal component of the lower cra nial nerves. Patients with a limited volume of disease in the middle ear can be treated either with a transcanal endoscopic approach or with a tympanomastoidectomy with extended facial recess in the setting of substantial middle ear and mastoid disease. The jugular bulb is not resected in these limited STR approaches. Instead, surgery seeks to control debilitating pulsa tile tinnitus and improve conductive hearing loss by the tar geted removal of middle ear disease In this study, we found that STR provides effective dis ease control and allows for individualized treatment strate gies tailored to the extent and volume of disease. Most patients in the STR cohort received a combined skull base and cervical approach, optimizing tumor access while pre serving lower CNs. In select cases, limited resection of middle ear and mastoid PGL components was performed. Patients presenting with significant intracranial tumor invol vement also benefitted from a multidisciplinary approach with microsurgical removal of the intracranial component to relieve brainstem compression. There was no difference in terms of new-onset cranial neuropathies between different types of STR. In the present study, we found lower rates of new lower cranial neuropathies following STR compared with those reported after GTR. 4,5,11 Specifically, postoperative neuropa thy involving CN X and XII occurred in 3 (7%) and 1 (2%) patients, respectively. In a previously reviewed cohort from our institution (1971-2006, n = 238), 90% of patients

underwent GTR, with a 60% LCN rate after surgery (IX = 40%, X = 24%, XI = 26%, XII = 21%). 3 In one of the largest operative series of jugular PGL treated primarily with GTR, Bacciu et al 5 reported LCN rates between 22.8% and 50%, similar to other large institutional series. 5 Overall, there was 100% local control in patients treated with combined modality treatment. Two patients with single modality treatment were awaiting salvage treatment at the time of study conclusion. Type 1 STR was associated with increased risk of regrowth, although there was no statisti cally significant differences in terms of preoperative and postoperative tumor volumes or disease stage (Glasscock Jackson) between cohorts. There was no difference in the need for adjuvant radiation or salvage therapy–free survival between types of STR. We did not use disease-free interval or progression-free survival analysis to limit immortal time bias, which is inherent in this cohort treated with multiple and variable techniques at heterogenous time points. EOR was also not a significant predictor of regrowth or need for salvage radiation, but this may reflect a statistical limitation related to the present analysis usage of an actuarial volumetric estimation of EOR. In contrast, Wanna et al 1 pre viously noted regrowth in cases that had more than 20% of residual tumor using an ellipsoid-based estimation of tumor volume. 1 Further high-powered studies contrasting EOR using different methods of volumetric estimation will yield more insight about this predictor. The role of radiation (stereotactic or IMRT) therapy in a salvage or adjuvant setting has recently been reviewed with resultant excellent local control of disease and minimal associated toxicity. 12 Previous reports have also highlighted STR with targeted radiation for optimal tumor The present study reports outcomes of conservative surgical approaches for neural preservation in jugular PGL. This is the first study that uses actuarial volumetric analysis of these complex tumors to ascertain predictors of tumor regrowth and need for postsurgical intervention. Major limitations include the inability to assess the preintervention growth rate as most of these lesions presented at advanced stage and lacked preoperative, serial imaging. There was also lack of genetic information (presence and type of succinate dehydro genase mutation). We were also able to analyze volumetric data for only 21 of the 32 patients who underwent STR, hence limiting the sample size in each type of STR. The rel atively small sample size prevented the use of multivariate regression. Larger pooled studies with meta-analysis are needed to analyze these predictors. Conclusion Conservative surgical management of jugular PGL with tar geted STR based on the extent and location of tumor yields in lower new-onset LCN. Local tumor control can be achieved with radiation therapy in both salvage and adjuvant settings at short-term follow-up. Studies with longer control with minimal morbidity. 6,9 Strengths and Limitations