Satyan B. Sreenath

Endoscopic skull base reconstruction: a review and clinical case series of 152 vascularized flaps used for surgical skull base defects in the setting of intraoperative cerebrospinal fluid leak.

Endoscopic skull base surgery continues to rapidly evolve, requiring comparable advances in reconstructive techniques. While smaller skull base defects with low intraoperative CSF flow have been successfully managed with a variety of avascular and/or noncellular techniques, larger defects with high CSF flow require more robust repairs often in the form of vascularized flaps, which confer excellent success rates in this setting. Despite these successful outcomes, a paucity of data describing specific patient and operative characteristics and their effects on repair exist. Therefore, a retrospective, consecutive chart review was performed on patients who underwent endoscopic skull base reconstruction with a vascularized flap in the setting of intraoperative CSF leaks. In this series, 151 patients with a mean age of 51 years underwent 152 vascularized flap skull base reconstructions for an array of benign and malignant pathologies. These vascularized flaps included 144 nasoseptal flaps, 6 endoscopic-assisted pericranial flaps, 1 facial artery buccinator flap, and 1 inferior turbinate flap that were used throughout all regions of the skull base. Perioperative (< 3 months) and postoperative (> 3 months) flap complications were assessed and revealed 3 perioperative flap defects (2.0%) defined as a visualized defect within the substrate of the flap and a total of 5 perioperative CSF leaks (3.3%). No patient experienced flap death/complete flap loss in the cohort. Assessed postoperative flap complications included 1 case (0.7%) of mucocele formation, 8 cases (5.3%) of prolonged skull base crusting, and 2 cases (1.3%) of donor-site complication, specifically septal perforation secondary to nasoseptal flap harvest. Among the 152 cases identified, 37 patients received radiation therapy while 114 patients did not undergo radiation therapy as part of the treatment profile. No significant association was found between perioperative complication rates and radiation therapy (p = 0.634). However, a significant association was found between postoperative complication rates and radiation therapy, primarily accounted for by an increased risk for prolonged (> 6 months) skull base crusting (p = 0.025). It is clear that larger skull base defects with high intraoperative CSF flow require thoughtful approach and strong consideration for vascularized repair.

Comparison of Socioeconomic and Demographic Factors in Patients with Chronic Rhinosinusitis and Allergic Fungal Rhinosinusitis

Objective The primary objective of this study is to evaluate the differences in socioeconomic, demographic, and disease severity factors between patients with chronic rhinosinusitis (CRS) and those with allergic fungal rhinosinusitis (AFRS). Study Design A retrospective cohort analysis was performed. Setting The study was conducted at the hospital of the University of North Carolina at Chapel Hill. Subjects and Methods A total of 186 patients were included (93 AFRS, 93 CRS with and without nasal polyps). Socio- economic and demographic data were obtained from the North Carolina State Data Center. Indicators of disease severity were measured by Lund-Mackay scores, serum immunoglobulin E (IgE) levels, diagnosis of asthma and/or allergic rhinitis, and the number of surgeries and computed tomography scans performed. Associations were analyzed with Fisher’s exact, Wilcoxon rank sum, and Pearson’s correlations tests. Results Compared with patients with AFRS, patients in both CRS groups were predominantly white (P < .0001), were older at the time of diagnosis (P < .0001), had higher county-based income per capita (P = .004), had lower quantitative serum IgE level (P < .001), and had lower Lund-Mackay scores (P < .0001). No associations between disease severity, socioeconomic status, and demographic factors were found within the CRS groups. Conclusion Within our cohort of patients residing in North Carolina, those with CRS have higher income, more access to primary care, and lower markers of disease severity than those with AFRS. These data continue to support the notion that AFRS merits classification as a distinct subtype of CRS.

Endoscopic Resection of Sinonasal Malignancy A Systematic Review and Meta-analysis

Objectives The use of endoscopic approaches for sinonasal malignancy resection has increased, but survival data are limited secondary to disease rarity and new surgical technique. Here we present a systematic review and meta-analysis of endoscopic endonasal resection of sinonasal malignancy. Data Sources MEDLINE, PubMed Central, NCBI Bookshelf, Cochrane Library, clinicaltrials.gov, National Guideline Clearinghouse. Review Methods PRISMA/MOOSE guidelines were followed. MeSH terms were “endoscopic” AND (“esthesioneuroblastoma” OR “sinonasal adenocarcinoma” OR “squamous cell carcinoma” OR “sinonasal undifferentiated carcinoma”). For studies in which individual-level data were available, results were obtained by direct pooling. For studies in which only summary Kaplan-Meier curves were available, numerical data were extracted, traced, and aggregated by fitting a Weibull model. Results Of 320 studies identified, 35 case series were included (n = 952 patients), with 15 studies analyzed via aggregate modeling and 20 studies analyzed via direct pooling. Two- and 5-year survival rates for patients in aggregate modeling were 87.5% and 72.3%, respectively (mean follow-up: 32.9 months). Two- and 5-year survival for patients in direct pooling were 85.8% and 83.5%, respectively (mean follow-up: 43.0 ± 19.5 months). Significant overall survival difference was found between low- and high-grade cancers (P = .015) but not between low- and high-stage cancers (P = .79). Conclusion Overall 2- and 5-year survival rates are comparable and sometimes greater than those from open craniofacial resection. Survival rates significantly differ by cancer grade but not stage. Journals and investigators should be encouraged to publish retrospective and prospective case series with staged survival updates based on established guidelines.

The combined endonasal and transoral approach for the management of skull base and nasopharyngeal pathology: a case series

The posterior skull base and the nasopharynx have historically represented technically difficult regions to approach surgically given their central anatomical locations. Through continued improvements in endoscopic instrumentation and technology, the expanded endonasal approach (EEA) has introduced a new array of surgical options in the management of pathology involving these anatomically complex areas. Similarly, the transoral robotic surgical (TORS) approach was introduced as a minimally invasive surgical option to approach tongue base, nasopharyngeal, parapharyngeal, and laryngeal lesions. Although both the EEA and the TORS approach have been extensively described as viable surgical options in managing nasopharyngeal and centrally located head and neck pathology, both endonasal and transoral techniques have inherent limitations. Given these limitations, several institutions have published feasibility studies with the combined EEA and TORS approaches for a variety of skull base and nasopharyngeal pathologies. In this article, the authors present their clinical experience with the combined endonasal and transoral approach through a case series presentation, and discuss advantages and limitations of this approach for surgical management of the middle and posterior skull base and nasopharynx. In addition, a presentation is included of a unique, simultaneous endonasal and transoral dissection of the nasopharynx through an innovative intraoperative setup.

Endoscopic Sinonasal Meningoencephalocele Repair A 13-Year Experience with Stratification by Defect and Reconstruction Type

Objective Sinonasal meningoencephalocele is a rare defect, with varying etiologies and treatment strategies. Here we present the largest published series from a single institution of patients with endoscopic repair. The primary goal is to examine rates of success with consideration to accompanying patient demographic data. The secondary goal is to report the results stratified by defect and reconstruction type. Design Retrospective consecutive case series. Setting Tertiary care academic center. Subjects and Methods Consecutive patients with CPT codes for skull base meningoencephalocele repair between May 2000 and March 2013 were reviewed. Patients who specifically had sinonasal defects were included. Results During the study period, 149 cases of sinonasal meningoencephaloceles were managed in 133 patients. Mean follow-up was 21.3 months (range, 0-116). There was a success rate of 88% for initial repair, with mean recurrence time of 8.3 months (range, 0-38), and a success rate of 93.8% for initial recurrence surgery, with 99.3% of ultimate successful repair. All cases were repaired endoscopically. Recurrence rate was not significantly related to location of defect (P = .682), size of defect (P = .434), particular reconstruction technique (P = .163), or etiology (trauma, P = .070). Overall complication rate was 11.3%. Conclusion Endoscopic sinonasal meningoencephalocele repair has excellent long-term results and may be considered as a primary approach. Surgeon comfort with a particular technique should be the most important factor used to guide choice of reconstruction.

A prospective randomized cohort study evaluating 3 weeks vs 6 weeks of oral antibiotic treatment in the setting of “maximal medical therapy” for chronic rhinosinusitis

Surprisingly, little literature exists evaluating the optimal duration of antibiotic treatment in “maximal medical therapy” for chronic rhinosinusitis (CRS). As such, we investigated whether 3 weeks vs 6 weeks of antibiotic therapy resulted in significant differences in clinical response.

Transfacial and Craniofacial Approaches for Resection of Sinonasal and Ventral Skull Base Malignancies

Malignancies of the paranasal sinuses and ventral skull base present unique challenges to physicians. A transfacial or craniofacial approach allows for wide, possibly en bloc, resection and is ideal for tumors that involve surrounding soft tissue, the palate, the orbit, anterolateral frontal sinus, and lateral dura. Transfacial approaches include a lateral rhinotomy often combined with a medial, subtotal, or total maxillectomy. Reconstruction is most commonly performed with a pericranial flap to separate the intranasal and intracranial compartments. These approaches have evolved and been refined but now are usually reserved for advanced tumors not amenable to endoscopic resection.

The Expanded Endoscopic Endonasal Approach to Anterior Communicating Artery Aneurysms: A Cadaveric Morphometric Study

OBJECTIVE The purpose of this study was to explore the endoscopic endonasal approach to the anterior communicating artery complex. DESIGN Anatomic, morphometric analysis of human cadaver heads. SUBJECTS Fifteen latex-injected adult cadaver heads. MAIN OUTCOME MEASURES The anatomic boundaries of the operative field and the dimensions of exposure of the anterior communicating artery (ACoA) complex were measured and clip placement feasibility was assessed. RESULTS Exposure of the ACoA and bilateral A1 and A2 segments was accomplished in all 15 cadaver heads. Average length of the exposed ACoA was 3 ± 1 mm, the left A1 was 5 ± 3 mm and right A1 was 5 ± 1 mm, while the A2 segment was 5 ± 2 mm bilaterally. The average distance from the alar floor to the ACoA was 95 mm, while proximal lateral limit measured between the alar floor margins was 36 mm. The distal lateral limit as defined by the distance between the lateral most exposed margins of the chiasm was 19 mm. Clip placement was accomplished for the ACoA and the A1 and A2 segments bilaterally in all specimens. CONCLUSION The endoscopic, endonasal transtuberculum, transplanum approach is an anatomically feasible alternative to treating select aneurysms of the ACoA complex.

A New Window for the Treatment of Posterior Cerebral Artery, Superior Cerebellar Artery, and Basilar Apex Aneurysm: The Expanded Endoscopic Endonasal Approach

OBJECTIVE To explore the feasibility of an endoscopic endonasal transclival approach to treat aneurysms arising in the basilar apex, posterior cerebral arteries, and superior cerebellar arteries. STUDY DESIGN Cadaveric anatomical study. PARTICIPANTS Fifteen cadaveric specimens. MAIN OUTCOME MEASURES Degree of surgical exposure of each artery attained, distance from the nasal vestibule to these three arteries, and feasibility of clipping these vessels using standard vascular clip applicators. RESULTS Both posterior cerebral arteries were exposed, 0.67 cm (standard deviation [SD]: 0.2) on the right side and 0.59 cm (SD: 0.2) on the left side. Both right and left superior cerebral arteries were exposed, 0.6 cm (SD: 0.2) and 0.7 cm (SD: 0.3), respectively. The length of the basilar artery exposed was 2.6 cm (SD: 0.3). The distance from the nasal vestibule to the posterior cerebral artery, superior cerebellar artery, and basilar apex was 10 cm with an SD of ± 0.7, 0.6, and 0.8 cm, respectively. We were able to apply clips on each of these three vessels with a minimal alteration of surrounding normal tissue. CONCLUSION The endoscopic endonasal transclival approach represents a potentially feasible surgical corridor to treat aneurysms arising from these vessels.

The Reverse-Flow Facial Artery Buccinator Flap for Skull Base Reconstruction: Key Anatomical and Technical Considerations

Objective To highlight key anatomical and technical considerations for facial artery identification, and harvest and transposition of the facial artery buccinator (FAB) flap to facilitate its future use in anterior skull base reconstruction. Only a few studies have evaluated the reverse-flow FAB flap for skull base defects. Design Eight FAB flaps were raised in four cadaveric heads and divided into thirds; the facial arterys course at the superior and inferior borders of the flap was measured noting in which incisional third of the flap it laid. The flaps reach to the anterior cranial fossa, sella turcica, clival recess, and contralateral cribriform plate were studied. A clinical case and operative video are also presented. Results The facial artery had a near vertical course and stayed with the middle (⅝) or posterior third (⅜) of the flap in the inferior and superior incisions. Seven of eight flaps covered the sellar/planar regions. Only four of eight flaps covered the contralateral cribriform region. Lastly, none reached the middle third of the clivus. Conclusions The FAB flap requires an understanding of the facial arterys course, generally seen in the middle third of the flap, and is an appropriate alternative for sellar/planar and ipsilateral cribriform defects.