Frederick Yoo
University of California, Los Angeles
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Frederick Yoo.
International Forum of Allergy & Rhinology | 2018
Frederick Yoo; Elisabeth H. Ference; Edward C. Kuan; Jivianne T. Lee; Marilene B. Wang; Jeffrey D. Suh
Functional endoscopic sinus surgery (FESS) is an effective treatment for chronic rhinosinusitis (CRS). Postoperative management strategies after FESS often vary from surgeon to surgeon. Recent data suggests that nasal saline irrigation following FESS is almost universally recommended; however, patient adherence has not been formally evaluated. The purpose of this study is to evaluate postoperative nasal irrigation practices and its effects on short‐term outcomes in post‐FESS patients.
Skull Base Surgery | 2016
Edward C. Kuan; Frederick Yoo; Jennifer Chyu; Marvin Bergsneider; Marilene B. Wang
Objectives Rathkes cleft cysts (RCC) are benign cystic lesions of the sella resulting from incomplete obliteration of Rathkes cleft. Symptomatic lesions often require surgical decompression, which is often amenable to a transnasal, transsphenoidal (TNTS) approach. We report our experience with marsupialization of RCC and describe a novel technique to promote re‐epithelization of the cyst cavity. Design Retrospective review. Setting Tertiary academic medical center. Participants Patients who underwent TNTS for RCC between 2007 and 2015. Main Outcome Measures Demographics, lesion characteristics, and reconstruction and treatment outcomes. Results In total, 52 patients were identified. The mean age was 41 ± 18 years. The mean RCC size was 13 ± 5 mm. Intraoperative cerebrospinal fluid (CSF) leak was encountered in 14 (27%) patients; all were repaired. There were six complications (12%) and no deaths. Mean follow‐up was 20 ± 18 months, with five (10%) recurrences. RCC size was associated with intraoperative CSF leak (p = 0.04). In 12 patients, the marsupialized cyst cavity was lined with a free mucosal graft (FMG) to promote healing and re‐epithelialization. Conclusions The TNTS approach is safe and effective in surgical decompression of RCC. Lining the exposed cyst cavity with an FMG is a simple intervention without added morbidity that may promote formation of an epithelialized tract. Level of Evidence Not applicable.
Skull Base Surgery | 2016
Frederick Yoo; Marilene B. Wang; Marvin Bergsneider; Jeffrey D. Suh
Objectives Bilateral anterior skull base (ASB) defects following endoscopic endonasal tumor resection are most commonly repaired utilizing multilayered reconstruction with a vascularized mucosal flap. Single‐layer closure of large ASB defects has been described in the literature but this technique has yet to gain a widespread use. We report our experience with a series of patients who underwent reconstruction of large ASB defects using a single‐layer intradural graft, without nasoseptal flaps. We also compared the use of acellular dermal matrix (AlloDerm, LifeCell, Branchburg, New Jersey, United States) or collagen matrix xenograft (Duramatrix, Stryker, Kalamazoo, Michigan, United States) as the graft biomaterial. Design A retrospective case series. Setting Tertiary academic medical center. Main Outcome Measures Postoperative cerebrospinal fluid leak, the number of postoperative debridements, the number of postoperative infections, and time to remucosalization. Results Two patients were reconstructed with AlloDerm and three with Duramatrix, with all patients receiving postoperative external beam radiation. There were no postoperative cerebrospinal fluid leaks identified in these patients during follow‐up. The AlloDerm group showed increased postsurgical crusting, the number of clinically apparent postoperative infections, and an increased time to remucosalization. Conclusions Single‐layer repair without a vascularized mucosal flap is a viable method of skull base repair for large ASB defects. We found repair with Duramatrix was superior, with less graft crusting and infection, requiring fewer debridements.
Skull Base Surgery | 2017
Edward C. Kuan; Frederick Yoo; Pratik B. Patel; Brooke M. Su; Marvin Bergsneider; Marilene B. Wang
Objectives/Hypotheses The endoscopic endonasal approach (EEA) is the workhorse endoscopic procedure for sellar and parasellar pathology. Various reconstruction techniques have been reported following EEA surgery, ranging from no reconstruction to vascularized flaps. We review our institutions experience with sellar reconstruction following EEA and propose an evidence‐based algorithm. Design Retrospective review. Setting Tertiary academic medical center. Participants Patients who underwent endoscopic EEA surgery for sellar or parasellar pathology between March 1, 2013 and August 31, 2016. Main Outcome Measures Patient demographic and clinicopathologic data were collected. Outcome measures included intraoperative and postoperative cerebrospinal fluid (CSF) leak rates and extent of resection (gross or subtotal). Results Three hundred consecutive patients were included. Depending on the presence and grade of intraoperative CSF leak, cases were reconstructed using either a free mucosal graft (FMG) or nasoseptal flap (NSF). Intraoperative and postoperative CSF leak rates were 30.7% and 2.3%, respectively. Multivariable logistic regression found that intraoperative CSF leak was associated with recurrent disease (odds ratio [OR] 2.47, p = 0.004), with no apparent predictors of postoperative CSF leak. Conclusions Based on this large series, we propose the following algorithm for sellar reconstruction: FMG for no CSF leak; fat graft + FMG ± rigid fixation for low‐grade leaks; and fat graft + NSF ± rigid fixation for high‐grade leaks.
American Journal of Otolaryngology | 2017
Pratik B. Patel; Edward C. Kuan; Kevin A. Peng; Frederick Yoo; Scott D. Nelson; Elliot Abemayor
PURPOSE Angiosarcoma of the tongue is an exceedingly rare malignancy of the head and neck. Such lesions can be primary in nature or occur in a previously irradiated field. We examine a series of cases with relation to clinical presentation, diagnosis, management, and outcomes. MATERIALS AND METHODS Retrospective chart review of all patients with angiosarcoma of the tongue at a tertiary academic institution yielded a single case between 2005 and 2016. The MEDLINE database was additionally searched for all case series or reports of angiosarcoma arising in the tongue, and pertinent clinical data were extracted. RESULTS The clinical presentation, disease course, and management of a patient with angiosarcoma of the tongue are presented. Institutional and literature search yielded a total of eight patients with angiosarcoma of the tongue. The most common primary sites were dorsal and lateral oral tongue. Treatment consisted of surgical resection in 63% of cases with adjuvant therapy administered in 75% of cases. Follow-up times varied per patient, but 63% had persistent or recurrent disease and 67% died of or with disease within two years of index presentation. CONCLUSION Angiosarcoma of the tongue is a rare and highly aggressive tumor, accounting for fewer than 1% of all head and neck malignancies. The mainstay of treatment is surgical resection with negative margins followed by adjuvant chemoradiation for high-risk features. Due to rarity of the disease, consensus on optimal treatment approach is lacking, and multi-center prospective studies would be helpful to set clinical guidelines.
Skull Base Surgery | 2016
Edward C. Kuan; Frederick Yoo; Won Kim; Karam W. Badran; Thomas E. Heineman; Ali R. Sepahdari; Marvin Bergsneider; Marilene B. Wang
Objectives/Hypotheses Functioning pituitary adenomas may produce endocrinopathies such as acromegaly and Cushing syndrome. Both conditions lead to characteristic anatomic variations as a result of hormonally induced abnormal soft tissue deposition. We evaluate the anatomic differences between acromegalics and Cushing disease patients and compare these dimensions to controls. Design Radiographic review of preoperative magnetic resonance images (MRI) of the pituitary gland. Setting Tertiary academic medical center. Participants Patients who underwent transnasal, transsphenoidal surgery for pituitary adenomas found to have acromegaly or pituitary Cushing between January 1, 2007 and September 1, 2015. A total of 15 patients with similar MRIs and no history of pituitary or sinonasal disease were selected as controls. Main Outcome Measures Dimensions assessed were intercarotid distance; carotid canal width; piriform aperture width; distance from the piriform aperture to the anterior face of the sphenoid; sphenoid sinus height, width, and length; angle from anterior nasal spine to anteroinferior face of sphenoid sinus; choanal height; and nasal cavity height at the level of the vertical segment of the middle turbinate. Sphenoid sinus pneumatization patterns were recorded. Results There were 30 acromegalics and 31 Cushing disease patients. When compared with controls, both acromegalics and Cushing disease patients had significantly wider piriform apertures and a longer distance from the piriform aperture to the anterior face of the sphenoid sinus (p < 0.05). Acromegalics had a significantly less acute angle (19 ± 3 degrees) from the anterior nasal spine to the sphenoid (p < 0.05). Cushing disease patients had significantly lower sphenoid sinus length and shorter nasal cavity height (p < 0.05). There were no differences in intercarotid distance or carotid canal width. Conclusions As acromegalics and Cushing disease patients have known anatomic variations, the skull base surgeon should be aware of these differences and adapt their techniques and approaches as needed.
Current Opinion in Otolaryngology & Head and Neck Surgery | 2016
Frederick Yoo; Jeffrey D. Suh
Purpose of review To perform analysis of evidence in current literature on the topic of genetics and chronic rhinosinusitis (CRS), with a particular focus on recent findings in the cystic fibrosis transmembrane regulator (CFTR), genes associated with primary ciliary dyskinesia, and taste receptor T2R38. Other genes that have been found to have association with CRS are also presented and discussed. Recent findings Recent studies in CFTR and CRS research have investigated possible CFTR-potentiators for treatment of refractory CRS. The T2R38 gene has been shown to be applicable in the clinical setting with a testable phenotype and may have a role in the prognosis and influencing management strategies of CRS patients. Many genes of the immune system have been studied, with genome-wide association studies and candidate-gene approaches identifying new associations that will need replication and further elucidation. Summary CRS is a multifactorial disease, with strong evidence of a genetic component in its pathophysiology for some cases. Currently, there are over 70 genes that have been genetically associated with CRS in the past 15 years. Future investigations into genetic causes and predispositions of CRS may allow for improved prognostication and development of disease-prevention strategies as well as novel therapeutic targets.
Skull Base Surgery | 2016
Frederick Yoo; Edward C. Kuan; Marvin Bergsneider; Marilene B. Wang
Pituitary | 2018
Frederick Yoo; Edward C. Kuan; Anthony P. Heaney; Marvin Bergsneider; Marilene B. Wang
Skull Base Surgery | 2017
Edward C. Kuan; Frederick Yoo; Pratik B. Patel; Brooke M. Su; Marvin Bergsneider; Marilene Wang