Optimizing Quality of Life and Minimizing Morbidity through Nasal Preservation in Endoscopic Skull Base Surgery: A Contemporary Review.

Introduction Endoscopic endonasal approaches (EEAs) are increasingly utilized for intracranial pathology. As opposed to sinonasal tumors, the nasal cavity is being used as a corridor to access these intracranial tumors but is not the site of primary surgical intent. Accordingly, there has been recent interest in preserving intranasal structures not directly involved by tumor and improving postoperative sinonasal quality of life (QOL). Objectives The aim of the study is to highlight recent advances in EEA techniques focused on improving sinonasal QOL including turbinate preservation, reducing the morbidity of reconstructive techniques, and the development of alternative minimally invasive EEA corridors. Methods The method of the study involves contemporary literature review and summary of implications for clinical practice. Results Nasoseptal flap (NSF) harvest is associated with significant morbidity including septal perforation, prolonged nasal crusting, and external nasal deformities. Various grafting and local rotational flaps have demonstrated the ability to significantly limit donor site morbidity. Free mucosal grafts have re-emerged as a reliable reconstructive option for sellar defects with an excellent sinonasal morbidity profile. Middle turbinate preservation is achievable in most EEA cases and has not been shown to cause postoperative obstructive sinusitis. Recently developed minimally invasive EEA techniques such as the superior ethmoidal approach have been described to better preserve intranasal structures while allowing intracranial access to resect skull base tumors and have shown promising sinonasal QOL results. Conclusion This contemporary review discusses balancing effective skull base reconstructive techniques with associated morbidity, the role of turbinate preservation in EEA, and the development of unique EEA techniques that allow for increased nasal structure preservation.

Retrospective Review of Surgical Site Infections after Endoscopic Endonasal Sellar and Parasellar Surgery: Multicenter Quality Data from the North American Skull Base Society.

Introduction Transnasal access to the anterior skull base provides a minimally invasive approach for sellar and parasellar masses compared with its open counterparts. The unique microbiome of the sinonasal mucosa provides distinct challenges not encountered with other cranial approaches. The use of antibiotics in these cases has not been standardized, and data remain scarce regarding infectious outcomes. Methods We conducted a multicenter retrospective analysis of shared quality data points for the endoscopic endonasal approach (EEA) for pituitary adenomas, along with other sellar and parasellar region masses that were included by participating institutions. Patient and operative characteristics, perioperative and postoperative antibiotic regimens and their durations, intraoperative and postoperative cerebrospinal fluid leak, and onset of postoperative meningitis and sinusitis were compared. Results Fifteen institutions participated and provided 6 consecutive months' worth of case data. Five hundred ninety-three cases were included in the study, of which 564 were pituitary adenomectomies. The incidences of postoperative meningitis and sinusitis were low (0.67 and 2.87% for all pathologies, respectively; 0.35% meningitis for pituitary adenomas) and did not correlate with any specific antibiotic regimen. Immunocompromised status posed an increased odds of meningitis in pituitary adenomectomies (28.6, 95% confidence interval [1.72-474.4]). Conclusions The results show no clear benefit to postoperative antimicrobial use in EEA, with further larger studies needed.

Esthesioneuroblastoma (Olfactory Neuroblastoma): Overview and Extent of Surgical Approach and Skull Base Resection.

Esthesioneuroblastoma is a rare malignancy originating from the olfactory epithelium. Treatment consists of surgical resection with strong consideration for adjuvant treatment in advanced Kadish stage and high Hyams grade. In the modern era, overall outcomes for esthesioneuroblastoma are favorable compared with many other sinonasal malignancies with 5-year overall survival estimated to be 80%. When selecting the optimal surgical approach, the surgeon must consider the approach that will allow for a negative margin resection and adequate reconstruction. In appropriately selected patients, endoscopic outcomes appear at least equivalent to open approaches and unilateral endoscopic approach may be used in select olfactory preservation cases.

Contemporary Surgical Management of Juvenile Nasopharyngeal Angiofibroma.

Objectives Juvenile nasopharyngeal angiofibromas (JNAs) are uncommon tumors with an evolving treatment paradigm. The objective of this study was to compare our prior experience reported in 2005 with our most contemporary series to compare practice improvements and the impact of expanded endonasal procedures. Design Retrospective review comparing a contemporary 22 patients with JNA who underwent surgical management between 2005 and 2019, compared with a historical cohort of 65 patients from the same center. Results The most common presenting symptom was epistaxis (68%). The median maximum tumor diameter was 4.4 cm. All patients underwent preoperative embolization. An endoscopic endonasal approach (EEA) was used in 18 patients (82%), compared with 9% in the series prior to 2005. Gross total resection was achieved in all patients. The median estimated blood loss was 175 and 350 mL for EEA and open (transfacial) cases, respectively. Only two patients (9%) required a blood transfusion compared with 52% on the previous series. The median follow-up was 19 months. The overall recurrence rate was 9% in this series and 24% in the previous series. No patient required radiation therapy in follow-up compared with 3% in our historical cohort. Conclusion There have been significant changes regarding the management of patients with JNA compared with the previous Mayo Clinic experience. The EEA has become the preferred route over the transfacial approaches to treat JNA in selected patients who do not have intracranial extension. Preoperative embolization has aided in reducing the postoperative transfusion rates.

Timing of Postoperative CSF Leak after Endoscopic Skull Base Surgery in Patients with Obstructive Sleep Apnea.

Background There is little data regarding postoperative outcomes of patients with obstructive sleep apnea (OSA) undergoing skull base surgery. The purpose of this study is to determine an association between risk factors and proximity of cerebrospinal fluid (CSF) leak to surgery in patients with OSA undergoing endoscopic skull base surgery. Methods A retrospective review of neurosurgical inpatients, with and without OSA, at a tertiary care institution from 2002 to 2015 that experienced a postoperative CSF leak after undergoing endoscopic skull base surgery. Results Forty patients met inclusion criteria, 12 (30%) with OSA. OSA patients had significantly higher body mass index (BMI; median 39.4 vs. 31.7, p < 0.01) and were more likely to have diabetes (41.7 vs. 10.7%, p = 0.04) than non-OSA patients; otherwise there were no significant differences in clinical comorbidities. No patients restarted positive pressure ventilation (PPV) in the inpatient setting. The type of repair was not a significant predictor of the time from surgery to leak. Patients with OSA experienced postoperative CSF leak 49% sooner than non-OSA patients (Hazard Ratio 1.49, median 2 vs. 6 days, log-rank p = 0.20). Conclusion Patients with OSA trended toward leaking earlier than those without OSA, and no OSA patients repaired with a nasoseptal flap (NSF) had a leak after postoperative day 5. Due to a small sample size this trend did not reach significance. Future studies will help to determine the appropriate timing for restarting PPV in this high risk population. This is important given PPV's significant benefit to the patient's overall health and its ability to lower intracranial pressure.

A Cross-Sectional Survey of the North American Skull Base Society Part 3: The State of Lateral Skull Base Surgery Training in North America.

Introduction Optimal management of vestibular schwannoma (VS) demands involvement of an experienced multidisciplinary team. As the number of training programs in neurotology and skull base neurosurgery continues to rise, ensuring that trainees are capable of evidence-based decision-making and treatment, whether microsurgical or radiosurgical, is of paramount importance. The purpose of this study is to characterize the landscape of neurotologic and neurosurgical fellowship training programs in North America, with special reference to VS management. Methods A 64-item web-based survey assessing VS practice trends was devised by members of the North American Skull Base Society (NASBS) Research Task Force and distributed electronically to NASBS membership via SurveyMonkey as a cross-sectional study. Participation was entirely voluntary and there was no remuneration for survey completion. The survey link was active from November 29 to December 14, 2016. Results Of 719 members of the NASBS who were emailed a survey link, a total of 57 were returned (8%) completed surveys. Of all respondents, 51 (89%) claimed to have formal training in skull base neurosurgery or neurotology. Thirty-three respondents (65%) were skull base neurosurgeons while the remainder were neurotologists ( n = 18; 35%). Institutions with fellowship programs tended to have a higher surgical, radiosurgical, and overall case volume than those with a residency program alone. However, 20% of respondents at institutions with fellowship programs reported evaluating less than 50 new diagnoses of VS per year and 12% reported a surgical case volume of less than 10 cases per year. Conclusion As the number of skull base training programs expands, it is our duty to ensure that trainees gain sufficient experience to enter independent practice with the ability to exercise informed decision-making and safely perform VS surgery and radiosurgery. In the current training climate, implementing multidisciplinary care models, formalized training requirements, and emerging surgical simulators will support the development of minimum proficiencies in VS care.

Translabyrinthine Approach for Resection of Vestibular Schwannoma.

Objectives This video describes the surgical indications, relevant anatomy, and surgical steps of routine translabyrinthine surgery for gross total resection of sporadic vestibular schwannoma. Design The procedure is presented through a surgical instructional video. Setting The surgery took place at tertiary skull base referral center. Parcipant A 47-year-old patient reported with nonserviceable hearing, frequent episodes of vertigo, recurrent severe headache, and a small unilateral right sided vestibular schwannoma. Results Gross total resection with preservation of facial nerve function was achieved. Conclusion This instructional video documents the surgical steps and relevant anatomy for translabyrinthine resection of vestibular schwannoma. The link to the video can be found at: https://youtu.be/CJ2vKMLs7aI .

Esthesioneuroblastoma and Olfactory Preservation: Is it Reasonable to Attempt Smell Preservation?

Objective Olfactory preservation after resection of esthesioneuroblastoma (ENB) has been reported, however, the ability to predict tumor involvement of the olfactory system is critical to this surgical strategy. This study aims to answer the question: Can a surgeon predict, based on preoperative imaging, whether there is unilateral involvement of the olfactory system allowing for safe attempt of olfactory preservation? Methods This is a retrospective review of post-resection ENB meeting inclusion criteria of having bilateral olfactory tracts and bulbs submitted at the time of primary resection for pathologic margins. Five board-certified skull base surgeons blinded to the pathology individually reviewed the preoperative MRI scans to predict degree of tumor involvement. Results Olfactory bulb involvement occurred in both bulbs in 35% of cases and unilateral in 39% of cases, and there was no involvement in 26% of cases sampled. When comparing physician prediction of involved tracts or bulbs, involvement was appropriate or over-called (i.e., called positive when pathology was in fact negative) in 96% of cases. Conclusion This study demonstrates unilateral or no pathologic olfactory involvement of the olfactory system in 65% of cases. Our ability to predict this involvement, which may allow for a management strategy that attempts to preserve olfactory function, was accurate at 96%. Therefore, interpretation of imaging and proceeding with smell preservation in ENB appears reasonable in this cohort. LEVEL OF EVIDENCE: Level 2b.

Endoscopic and Microscopic Transsphenoidal Surgery of Craniopharyngiomas: A Systematic Review of Surgical Outcomes Over Two Decades.

OBJECTIVE: Few studies have compared transsphenoidal endoscopic (TE) and transsphenoidal microscopic (TM) techniques for the treatment of craniopharyngiomas. DESIGN: We performed a systematic review of published series. The results were stratified in two time periods from 1995 to 2016. RESULTS: A total of 48 articles and 1,186 patients met the inclusion criteria. Overall, 60% of endoscopic cases were supradiaphragmatic, and 76% of microsurgical cases were infradiaphragmatic. Mean tumor size was 3 cm and 2.4 cm in the TE and TM series, respectively (p = 0.008). Total resection rate was similar (66%) between TE and TM. Considering the surgical outcome for different tumor locations, total resection rate was slightly higher in the TE for supradiaphragmatic lesions (59% versus 42.5%; p = 0.26). Recurrence rate was higher in the endoscopic series (21.7% versus 12%). Mortality and the overall complication rates were similar (p = 0.84). However, hydrocephalus (7.6%) and cognitive dysfunction (15.8%) were more common in TE, and meningitis (6%) and endocrinologic complications were more common in the TM series. In the past 6 years, the rate of cerebrospinal fluid leak in TE was significantly lower (13%) and was comparable between TE and TM. CONCLUSION: Both techniques appear comparable for infradiaphragmatic lesions; however, TE seems to yield better results for supradiaphragmatic tumors. In conclusion, more complex lesions with difficult locations can be effectively treated with endoscopic surgery.

Morbid obesity increases risk of morbidity and reoperation in resection of benign cranial nerve neoplasms.

OBJECTIVE: Obesity has been associated with increased risk for postoperative CSF leak in patients with benign cranial nerve tumors. Other measures of postoperative morbidity associated with obesity have not been well characterized. METHODS: Patients enrolled in the American College of Surgeons' National Surgical Quality Improvement Program (ACS-NSQIP) from 2007 to 2013 with a diagnosis code of a benign neoplasm of a cranial nerve were included. The primary outcome of postoperative morbidity was analyzed as well as secondary outcomes of readmission and reoperation. The main covariate of interest was body mass index (BMI). RESULTS: A total of 561 patients underwent surgery for a benign cranial nerve neoplasm between 2007 and 2013. Readmission data, available for 2012-2013(n=353), revealed hydrocephalus, facial nerve injury, or CSF leak requiring readmission or reoperation occurred in 0.85%, 1.42%, and 3.12%, respectively. Composite morbidity included wound complications, infection, respiratory insufficiency, transfusion requirement, stroke, venous thromboembolism, coma and cardiac arrest. On multivariable analysis patients with class I (BMI 30-34.9) and II (BMI 35-39.9) obesity showed trends towards increasing return to operating room, though not significant, but there was no trend for composite complications in class I and II obesity patients. However, class III obesity, BMI≥40, was associated with increased odds of composite morbidity (OR 4.40, 95% CI 1.24-15.88) and return to the operating room (OR 5.97, 95% CI 1.20-29.6) relative to patients with a normal BMI, 18.5-25. CONCLUSIONS: Obesity is an independent and important risk factor for composite morbidity in resection of benign cranial nerve neoplasms, and as such, merits discussion during preoperative counseling.