Pontine encephalocele and abnormalities of the posterior fossa following transclival endoscopic endonasal surgery

Special Considerations in Pediatric Endoscopic Skull Base Surgery

Originally pioneered in adults, endoscopic endonasal approaches for skull base pathology are being increasingly applied as a minimally invasive alternative for young children. Intrinsic anatomic differences between these patient populations have sparked discussions on the feasibility, safety, and efficacy of these techniques in pediatric patients. This work aims to serve as a primer for clinicians engaged in the rapidly evolving field of pediatric endoscopic skull base surgery. A succinct overview of relevant embryology, sinonasal anatomy, and diagnostic workup is presented to emphasize key differences and unique technical considerations. Additional discussions regarding select skull base lesions, reconstructive paradigms, potential surgical complications, and postoperative care are also highlighted in the setting of multidisciplinary teams.

Skull Base Reconstruction by Subsite after Sinonasal Malignancy Resection

Reconstruction after the resection of sinonasal malignancies is complex and primarily dependent on the defect size and location. While the reconstructive paradigm for sellar mass resection is well delineated, the challenges associated with reconstruction after sinonasal malignancy resection are less well described. This narrative review will address the goals of reconstruction after both endonasal endoscopic and open sinonasal malignancy resection and reconstructive options specific to these subsites. The goals of reconstruction include repairing cerebrospinal fluid leaks, restoring sinonasal function, providing a nasal airway, and optimizing the patient's quality of life. These goals are often complicated by the anatomic nuances of each involved sinus. In this review, we will discuss the methods of reconstruction specific to each sinonasal subsite and describe the factors that guide choosing the optimal reconstructive technique.

Septal rhinopharyngeal flap: a novel technique for skull base reconstruction after endoscopic endonasal clivectomies

Endoscopic endonasal reconstruction techniques have improved CSF leak rates that were initially reported after surgery for cranial base and intradural lesions. However, wide surgical defects still pose a problem, especially if located in the clival region. The authors propose and describe a novel reconstruction technique they call a septal rhinopharyngeal flap (SRF) specifically designed to address this issue. The SRF is formed by three components of mucosa: 1) septal, 2) rhinopharyngeal roof, and 3) rhinopharyngeal posterior wall components, which allows for the coverage of the tuberculum/sellar region, midclivus, and lower clivus, respectively. A step-by-step procedure is described and its results analyzed in cases in which it has been used. The SRF was performed in 8 patients, which included diagnoses of 4 chordomas, 2 petroclival meningiomas, 1 invasive pituitary adenoma, and 1 chondrosarcoma. The size of the flap was considered optimal in all patients (100%). Postoperative MRI revealed contrast enhancement covering the entire surface of the flap. No CSF leaks were encountered after at least 1 postoperative year. The SRF is a novel vascularized reconstruction technique specifically indicated for wide endosanasal clivectomies focused on the middle clivus with caudal extension into the lower clivus and craniocervical junction, as well as rostral extensions into the tubercular or planum sphenoidale. This new reconstruction technique could be added to the skull base reconstruction armamentarium as a safe and optimal option.

Endoscopic Endonasal Surgical Strategy for Skull Base Chordomas Based on Tumor Growth Directions: Surgical Outcomes of 167 Patients During 3 Years

Background

Skull base chordomas (SBCs) are rare malignant bone tumors with dismal long-term local control. Endoscopic endonasal surgeries (EESs) are increasingly adopted to resect SBCs recently. Gross total resection (GTR) favors good outcomes. However, the SBCs often invade the skull base extensively and hide behind vital neurovascular structures; the tumors were challenging to remove entirely. To improve the GTR, we established a surgical strategy for EES according to the tumor growth directions.

Methods

A total of 112 patients with SBCs from 2018 to 2019 were classified into the derivation group. We retrospectively analyzed their radiologic images and operation videos to find the accurate tumor locations. By doing so, we confirmed the tumor growth directions and established a surgical strategy. Fifty-five patients who were operated on in 2020 were regarded as the validation group, and we performed their operations following the surgical strategy to verify its value.

Results

In the derivation group, 78.6% of SBCs invade the dorsum sellae and posterior clinoid process region. 62.5% and 69.6% of tumors extend to the left and right posterior spaces of cavernous ICA, respectively. 59.8% and 61.6% of tumors extend to the left and right posterior spaces of paraclival and lacerum ICA (pc-la ICA), respectively. 30.4% and 28.6% of tumors extended along the left and right petroclival fissures that extend toward the jugular foramen, respectively. 30.4% of tumors involved the foramen magnum and craniocervical junction region. The GTR was achieved in 60.8% of patients with primary SBCs in the derivation group. Based on the tumors’ growth pattern, pituitary transposition and posterior clinoidectomy techniques were adopted to resect tumors that hid behind cavernous ICA. Paraclival ICA transposition was used when the tumor invaded the posterior spaces of pc-la ICA. Lacerum fibrocartilage resection and eustachian tube transposition may be warranted to resect the tumors that extended to the jugular foramen. GTR was achieved in 75.0% of patients with primary SBCs in the validation group.

Conclusion

Besides the midline clival region, the SBCs frequently grow into the eight spaces mentioned above. The surgical strategy based on the growth pattern contributes to increasing the GTR rate.

[Multidisciplinary management of clival chordoma]

Chordoma of the clivus belong to the rare tumors of the skull base. Due to their aggresive behaviour including intradural infiltration of neurovascular structures an interdisciplinary treatment is mandatory. This article gives an overview on current surgical concepts including the endoscopic approach as well as the postoperative radiotherapy. Novel diagnostic tools and molecular targets to optimize individual tumor therapy are discussed.

Management of anterior fossa cephaloceles

Skull base cephaloceles (SBCs) are defined as herniation of intracranial content through the skull base and are classified based on composition, etiology, and topographic location. Anterior SBCs frequently protrude in the sinonasal cavity, and consequently are at potential risk of infection. Therefore, the current recommendation is to treat SBCs with the primary intent of preventing meningitis, and surgery represents the mainstay of treatment. Anterior SBCs may display a wide spectrum of severity and complexity, and in each case the risks and benefits of surgical approaches are to be carefully weighted based on thorough assessment of symptoms, age, general conditions, location and size of the lesion, as well as expertise of the surgeon. In the last 30 years, the evolution and diffusion of transnasal endoscopic surgery have substantially changed the surgical management of the majority of SBC. In the past, they were treated exclusively with open transcranial approaches that may be burdened by relevant morbidity and risk for severe complications. The transnasal endoscopic corridor now provides easy access to the lesion and different reconstructive strategies using endonasal pedicled flaps, without any external incision, cranioplasty or brain manipulation. However, there are still scenarios in which an exclusive transnasal endoscopic route is contraindicated. The aim of the present review was to provide an overview on the comprehensive management of anterior SBC, with a particular focus on lesions suitable for endoscopic surgery. Furthermore, special aspects of SBC management in children and adults will be highlighted.

Current opinion in otolaryngology and head and neck surgery: clival chordoma and its management

PURPOSE OF REVIEW

Chordomas of the clival region are challenging tumors to treat due to their location and infiltrative behavior. The primary goal of treatment remains a gross total resection (GTR). Advances in surgical techniques, especially the adoption of endoscopic endonasal techniques, provide improved rates of surgical resection while minimizing secondary surgical morbidities.

RECENT FINDINGS

Advances in the management of clival chordomas include further development of endoscopic endonasal approaches to the clivus and petroclival region, enhanced understanding of the biologic behavior of chordomas and prognostic value of molecular markers, and increased experience with newer radiation therapy modalities such as proton beam therapy.

SUMMARY

Improved surgical techniques enhance our ability to achieve a GTR while minimizing morbidity of surgery. Molecular markers may allow stratification of patients into prognostic groups and help direct further therapy. A combination of surgery with GTR and proton beam or intensity modulated radiotherapy currently offers the best potential for cure. Therapy with new immune system modulators is promising but is reserved for clinical trials.

ICAR: endoscopic skull-base surgery

BACKGROUND

Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS).

METHODS

Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated.

CONCLUSION

A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings.

Sellar trough technique for endoscopic endonasal transclival repair

Background:

Endoscopic endonasal transclival approaches provide direct access to the ventral skull base allowing the treating of clival and paraclival pathology without the manipulation of the brain or neurovascular structures. Postoperative spinal fluid leak, however, remains a challenge and various techniques have been described to reconstruct the operative defect. The “gasket seal” has been well-described, but has anatomic challenges when applied to clival defects. We describe a modification of this technique for use in endonasal transclival approaches.

Methods:

Two patients who underwent an endoscopic endonasal transclival approach for tumor resection with an intraoperative spinal fluid leak underwent a modified “gasket seal” closure technique for skull base reconstruction.

Results:

A 71-year-old woman with a petroclival meningioma and a 22 year old with a clival chordoma underwent endoscopic endonasal transclival resection with the modified repair. No new postoperative deficits occurred and no postoperative spinal fluid leak was seen with a follow-up of 17 and 23 months, respectively.

Conclusion:

We describe the successful use of a simple, low risk, and technique modification of the “gasket seal” technique adapted to the clivus that allows for hard reconstruction and facilitates placement of the nasoseptal flap.

Transclival approaches for intradural pathologies: historical overview and present scenario

Recently, endoscopic transsphenoidal transclival approaches have been developed and their role is widely accepted for extradural pathologies. Their application to intradural pathologies is still debated, but is undoubtedly increasing. In the past five decades, different authors have reported various extracranial, anterior transclival approaches for intradural pathologies. The aim of this review is to provide a historical overview of transclival approaches applied to intradural pathologies. PubMed was searched in October 2018 using the terms transcliv*, cliv* intradural, transsphenoidal transcliv*, transoral transcliv*, transcervical transcliv*, transsphenoidal brainstem, and transoral brainstem. Exclusion criteria included not reporting reconstruction technique, anatomical studies, reviews without new data, and transcranial approaches. Ninety-one studies were included in the systematic review. Since 1966, transcervical, transoral, transsphenoidal microsurgical, and, recently, endoscopic routes have been used as a corridor for transclival approaches to treat intradural pathologies. Each approach presents a curve that follows Scott's parabola, with evident phases of enthusiasm that quickly faded, possibly due to high post-operative CSF leak rates and other complications. It is evident that the introduction of the endoscope has led to a significant increase in reports of transclival approaches for intradural pathologies. Various reconstruction techniques and materials have been used, although rates of CSF leak remain relatively high. Transclival approaches for intradural pathologies have a long history. We are now in a new era of interest, but achieving effective dural and skull base reconstruction must still be definitively addressed, possibly with the use of newly available technologies.

Watertight Robust Osteoconductive Barrier for Complex Skull Base Reconstruction: An Expanded-endoscopic Endonasal Experimental Study

Endoscopic skull base reconstruction (ESBR) following expanded-endoscopic endonasal approaches (EEA) in high-risk non-ideal endoscopic reconstructive candidates remains extremely challenging, and further innovations are still necessary. Here, the aim is to study the reconstructive knowledge gap following expanded-EEA and to introduce the watertight robust osteoconductive (WRO)-barrier as an alternative durable option. Distinctively, we focused on 10 clinical circumstances. A 3D-skull base-water system model was innovated to investigate the ESBR under realistic conditions. A large-irregular defect (31 × 89 mm) extending from the crista galli to the mid-clivus was achieved. Then, WRO-barrier was fashioned and its tolerance was evaluated under stressful settings, including an exceedingly high (55 cmH₂O) pressure, with radiological assessment. Next, the whole WRO-barrier was drilled to examine its practical-safe removal (simulating redo-EEA) and the whole experiment was repeated. Finally, WRO-barrier was kept into place to value its 18-month long-term high-tolerance. Results in all experiments of WRO-barriers were satisfactorily fashioned to conform the geometry of the created defect under realistic circumstances via EEA, tolerated an exceedingly high pressure without evidence of leak even under stressful settings, resisted sudden-elevated pressure, and remained in its position to maintain long-term watertight seal (18 months), efficiently evaluated with neuroimaging and simply removed-and-reconstructed when redo-EEA is needed. In conclusion, WRO-barrier as an osteoconductive watertight robust design for cranial base reconstruction possesses several distinct qualities that might be beneficial for patients with complex skull base tumours.

Transcranial cerebellar herniation following craniotomy: Case report and literature review

To report a case of post-surgical encephalocele through craniotomy burr holes following the resection of a meningioma of the posterior fossa. A 49-year-old female presented in the emergency room with cephalea. The MRI showed a meningioma of the convexity of the posterior fossa. A resection was performed and the bone flap replaced. The patient recovered uneventfully and was discharged. After 30 days the patient consulted referring cephalea, vomiting and imbalance. Brain MRI revealed a trans-cranial cerebellar herniation through the craniotomy burr holes. An urgent surgery was performed to repair the encephalocele. Post-surgical brain MRI was performed and did not show complications. Post-surgical encephalocele is an uncommon complication after the resection of a posterior fossa lesion. To avoid this complication, it is recommended thorough dural and bony closure, particularly in the posterior fossa surgeries and in high-risk patients.

Delayed complications from expanded endonasal surgery for intracranial tumors

PURPOSE OF REVIEW

Delayed complications after endoscopic endonasal approaches to the skull base, defined as complications greater than 1 month postoperatively, are uncommon. These complications are divided into categories including sinonasal, neuroanatomic, endocrine and vascular. This review highlights the most up-to-date advancements and reviews the management of delayed complications for skull base patients.

RECENT FINDINGS

Over the last 10 years, the field of endoscopic endonasal skull base surgery has expanded with new data highlighting the long-term patient outcomes. The majority of patients experience increased quality of life (QOL) after these interventions. However, delayed complications including alterations to sinonasal function, delayed encephaloceles from the bony skull base defect and resulting endocrinopathies can significantly impact patient's QOL. Awareness of these complications and their current management is valuable for endoscopic surgeons.

SUMMARY

Endonasal approaches to the skull base are safe and well tolerated in properly selected patients. This article highlights the delayed complications that require recognition and management by skull base surgeons to ensure the best possible care for patients.

Pitfalls of skull base reconstruction in endoscopic endonasal approach

Various skull base reconstruction techniques have been developed in endoscopic endonasal approach (EEA) for skull base lesions to prevent postoperative cerebrospinal fluid (CSF) leakage. This study was performed to evaluate the efficacy and pitfalls of our method of skull base reconstruction after EEA. A total of 123 patients who underwent EEA (127 surgeries) between October 2014 and May 2017 were reviewed. Our algorithm for skull base reconstruction in EEA was categorized based on intraoperative CSF leakage graded as follows: grade 0 was excluded from this study; grade 1, dural suturing with abdominal fat graft or packing of gelatin sponge into the cavity; grade 2, method for grade 1 with addition of mucosal flap or nasoseptal flap (NSF); and grade 3, duraplasty in fascia patchwork closure with NSF. Bony reconstruction was not mandatory, and there was no postoperative bed rest or initial lumbar drainage (LD) insertion in any of the cases. Postoperative CSF leakage after EEA was mostly prevented (96.3%) by our algorithm without postoperative initial LD or bed rest. On the other hand, reconstruction surgery was required for postoperative CSF leakage in two cases-one with prior multitranssphenoidal surgery and radiotherapy and another patient with poor compliance due to communication difficulties. Both of the latter patients were obese. Greater care with regard to postoperative CSF leakage is required in patients with prior EEA with radiotherapy and obesity. In such high-risk patients, initial LD or bed rest may be required to prevent postoperative CSF leakage. It is also important to restrict activities that result in increased intracranial pressure.

Pediatric Endoscopic Endonasal Approaches for Skull Base Lesions in the Very Young: Is It Safe and Effective?

Introduction  The fully endoscopic expanded endonasal approach (EEA) has been shown to be safe and efficacious in pediatric patients. However, in the very young patient (ages six and under), the anatomical challenge of working through a small nasal corridor is problematic. The ability to repair the skull base and use a nasoseptal flap (NSF) has also been called into question. Here, we review skull base resections using EEA in patients aged 6 years and younger. Methods  A retrospective chart review was conducted on pediatric patients age 6 years and younger who underwent EEA skull base resections over a 3-year period (June 2014 through June 2017). Results  Eight children aged 6 and under with seven tumor pathologies underwent an EEA for the resection of their skull base tumors, with a mean follow-up of 1.45 years. Only chordoma cases required multiple-staged resections. There are no tumor recurrences to date. A high-flow intraoperative cerebrospinal fluid (CSF) leak was encountered in three cases, and there were no postoperative CSF leaks. CSF leaks were effectively repaired with NSFs. One patient suffered from postoperative hypopituitarism, one patient experienced recurrent epistaxis secondary to turbinate destruction by the tumor, and one patient expired 8 months postresection secondary to metastatic disease. Conclusion  In our case series, EEA for skull base tumors in children aged 6 and under was a safe and effective surgical approach. Skull base defects are able to be effectively addressed with typical repairs including NSFs. Larger studies are warranted to further investigate this technique in this pediatric population.

How I do it: endoscopic endonasal approach to the inferior third of the clivus

BACKGROUND

Nowadays, endoscopic endonasal expanded approach targeting for the clival lower third is well described in literature. Nonetheless, great variations can be found among surgical groups, specially during the earlier stages of this procedure.

METHOD

We present a step by step description of the clival lower third approach until entering the dural space, setting its bony limits. We describe the basipharyngeal flap tailoring as a helpful option for latter reconstruction. The study of cadaveric specimens adds clarifying dissections.

CONCLUSIONS

The expansion in the coronal plane is providential in most of the intradural lesions of the inferior clivus. Basipharyngeal flap may help seal the surgical defects in this area.

Endoscopic Resection of Clival Malignancies

Surgical management of clival lesions presents numerous therapeutic challenges because of the close proximity of surrounding critical structures. With a detailed understanding of the endoscopic endonasal approach and relevant considerations, appropriate lesions can be removed in a safe and minimally invasive manner. Use of this technique as a primary approach represents the standard of care for many lesions at leading skull base centers, although adjunct techniques may be necessary in extensive lesions and those with significant lateral extension.

Nasoseptal flap necrosis: a rare complication of endoscopic endonasal surgery

OBJECTIVE The vascularized nasoseptal flap (NSF) has become the workhorse for skull base reconstruction during endoscopic endonasal surgery (EES) of the ventral skull base. Although infrequently reported, as with any vascularized flap the NSF may undergo ischemic necrosis and become a nidus for infection. The University of Pittsburgh Medical Center's experience with NSF was reviewed to determine the incidence of necrotic NSF in patients following EES and describe the clinical presentation, imaging characteristics, and risk factors associated with this complication. METHODS The electronic medical records of 1285 consecutive patients who underwent EES at the University of Pittsburgh Medical Center between January 2010 and December 2014 were retrospectively reviewed. From this first group, a list of all patients in whom NSF was used for reconstruction was generated and further refined to determine if the patient returned to the operating room and the cause of this reexploration. Patients were included in the final analysis if they underwent endoscopic reexploration for suspected CSF leak or meningitis. Those patients who returned to the operating room for staged surgery or hematoma were excluded. Two neurosurgeons and a neuroradiologist, who were blinded to each other's results, assessed the MRI characteristics of the included patients. RESULTS In total, 601 patients underwent NSF reconstruction during the study period, and 49 patients met the criteria for inclusion in the final analysis. On endoscopic exploration, 8 patients had a necrotic, nonviable NSF, while 41 patients had a viable NSF with a CSF leak. The group of patients with a necrotic, nonviable NSF was then compared with the group with viable NSF. All 8 patients with a necrotic NSF had clinical and laboratory evidence indicative of meningitis compared with 9 of 41 patients with a viable NSF (p < 0.001). Four patients with necrotic flaps developed epidural empyema compared with 2 of 41 patients in the viable NSF group (p = 0.02). The lack of NSF enhancement on MR (p < 0.001), prior surgery (p = 0.043), and the use of a fat graft (p = 0.004) were associated with necrotic NSF. CONCLUSIONS The signs of meningitis after EES in the absence of a clear CSF leak with the lack of NSF enhancement on MRI should raise the suspicion of necrotic NSF. These patients should undergo prompt exploration and debridement of nonviable tissue with revision of skull base reconstruction.

Risk factors associated with postoperative cerebrospinal fluid leak after endoscopic endonasal skull base surgery

OBJECTIVE The aim in this paper was to determine risk factors for the development of a postoperative CSF leak after an endoscopic endonasal approach (EEA) for resection of skull base tumors. METHODS A retrospective review of patients who underwent EEA for the resection of intradural pathology between January 1997 and June 2012 was performed. Basic demographic data were collected, along with patient body mass index (BMI), tumor pathology, reconstruction technique, lumbar drainage, and outcomes. RESULTS Of the 615 patients studied, 103 developed a postoperative CSF leak (16.7%). Sex and perioperative lumbar drainage did not affect CSF leakage rates. Posterior fossa tumors had the highest rate of CSF leakage (32.6%), followed by anterior skull base lesions (21.0%) and sellar/suprasellar lesions (9.9%) (p < 0.0001). There was a higher leakage rate for overweight and obese patients (BMI > 25 kg/m²) than for those with a healthy-weight BMI (18.7% vs 11.5%; p = 0.04). Patients in whom a pedicled vascularized flap was used for reconstruction had a lower leakage rate than those in whom a free graft was used (13.5% vs 27.8%; p = 0.0015). In patients with a BMI > 25 kg/m², the use of a pedicled flap reduced the rate of CSF leakage from 29.5% to 15.0% (p = 0.001); in patients of normal weight, this reduction did not reach statistical significance (21.9% [pedicled flap] vs 9.2% [free graft]; p = 0.09). CONCLUSIONS Preoperative BMI > 25 kg/m² and tumor location in the posterior fossa were associated with higher rates of postoperative CSF leak. Use of a pedicled vascularized flap may be associated with reduced risk of a CSF leak, particularly in overweight patients.

Outcomes in transcranial microsurgery versus extended endoscopic endonasal approach for primary resection of adult craniopharyngiomas

OBJECTIVE Craniopharyngiomas have historically been resected via transcranial microsurgery (TCM). In the last 2 decades, the extended endoscopic endonasal (transtuberculum) approach to these tumors has become more widely accepted, yet there remains controversy over which approach leads to better outcomes. The purpose of this study is to determine whether differences in outcomes were identified between TCM and extended endoscopic endonasal approaches (EEEAs) in adult patients undergoing primary resection of suprasellar craniopharyngiomas at a single institution. METHODS A retrospective review of all patients who underwent resection of their histopathologically confirmed craniopharyngiomas at the authors' institution between 2005 and 2015 was performed. Pediatric patients, revision cases, and patients with tumors greater than 2 standard deviations above the mean volume were excluded. The patients were divided into 2 groups: those undergoing primary TCM and those undergoing a primary EEEA. Preoperative patient demographics, presenting symptoms, and preoperative tumor volumes were determined. Extent of resection, tumor histological subtype, postoperative complications, and additional outcome data were obtained. Statistical significance between variables was determined utilizing Student t-tests, chi-square tests, and Fisher exact tests when applicable. RESULTS After exclusions, 21 patients satisfied the aforementioned inclusion criteria; 12 underwent TCM for resection while 9 benefitted from the EEEA. There were no significant differences in patient demographics, presenting symptoms, tumor subtype, or preoperative tumor volumes; no tumors had significant lateral or prechiasmatic extension. The extent of resection was similar between these 2 groups, as was the necessity for additional surgery or adjuvant therapy. CSF leakage was encountered only in the EEEA group (2 patients). Importantly, the rate of postoperative visual improvement was significantly higher in the EEEA group than in the TCM group (88.9% vs 25.0%; p = 0.0075). Postoperative visual deterioration only occurred in the TCM group (3 patients). Recurrence was uncommon, with similar rates between the groups. Other complication rates, overall complication risk, and additional outcome measures were similar between these groups as well. CONCLUSIONS Based on this study, most outcome variables appear to be similar between TCM and EEEA routes for similarly sized tumors in adults. The multidisciplinary EEEA to craniopharyngioma resection represents a safe and compelling alternative to TCM. The authors' data demonstrate that postoperative visual improvement is statistically more likely in the EEEA despite the increased risk of CSF leakage. These results add to the growing evidence that the EEEA may be considered the approach of choice for resection of select confined primary craniopharyngiomas without significant lateral extension in centers with experienced surgeons. Further prospective, multiinstitutional collaboration is needed to power studies capable of fully evaluating indications and appropriate approaches for craniopharyngiomas.

Brain Herniation After Endoscopic Transnasal Resection of Anterior Skull Base Malignancies

BACKGROUND

Endoscopic endonasal approaches, when appropriate, allow a less invasive method to remove anterior skull base cancer than traditional external transfacial/craniofacial approaches. The resultant skull base defect can be significantly large, potentially extending from the posterior table of the frontal sinus to the tuberculum sellae in the sagittal plane, and from one lamina papyracea to the other in the coronal plane. However, frontal lobe herniation after such expanded endoscopic resection has been considered more of a theoretical than a practical occurrence.

OBJECTIVE

To report the occurrence of frontal lobe herniation into the sinonasal cavity after expanded endonasal approaches, and to analyze causes and pathogenetic mechanisms of this unusual complication, proposing how it could have been prevented.

METHODS

Two cases have been observed in 2 different skull base referral centers in the United States and Italy. Surgical and perioperative complications, postoperative course, and need for revisions were analyzed.

RESULTS

Available data support the hypothesis that this complication is not attributable to the size of the anterior skull base defect, to the surgical technique, or to the materials used for the reconstruction. We found that 1 possible contributing factor may be the presence of increased intracranial pressure associated with obesity and obstructive sleep apnea, observed in both patients.

CONCLUSION

Frontal lobe herniation must be considered as a possible, albeit rare, complication of expanded endoscopic anterior skull base resection. Preoperative investigations concerning the presence of obstructive sleep symptoms as well as proper identification of neuroimaging signs of intracranial hypertension are recommended for such cases.

Endoscopic Endonasal Anterior Skull Base Surgery: A Systematic Review of Complications During the Past 65 Years

BACKGROUND

Endoscopic skull base surgery is becoming more popular as an approach to the anterior skull base for tumors and cerebrospinal fluid (CSF) fistulae. It offers the advantages of better cosmesis and improved quality of life after surgery. We reviewed the complication rates reported in the literature.

METHODS

A literature search was performed in the electronic database Ovid MEDLINE (1950 to August 25, 2015) with the search item "([Anterior] AND Skull base surgery) AND endoscopic."

RESULTS

We identified 82 relevant studies that included 7460 cases. An average overall complication rate of 17.1% (range 0%-68.0%) and a mortality rate of 0.4% (0%-10.0%) were demonstrated in a total of 82 studies that included 7460 cases. The average CSF leak rate for all studies was 8.9% (0%-40.0%) with meningiomas and clival lesions having the greatest CSF leak rates. The most frequent benign pathology encountered was pituitary adenomas (n = 3720, 49.8% of all cases) and the most frequent malignant tumor was esthesioneuroblastoma (n = 120, 1.6% of all cases). Studies that included only CSF fistula repairs had a lower average total complication rate (12.9%) but a greater rate of meningitis compared with studies that reported mixed pathology (2.4% vs. 1.3%). A trend towards a lower total complication rate with increasing study size was observed.

CONCLUSIONS

The endoscopic approach is an increasingly accepted technique for anterior skull base tumor surgery and is associated with acceptable complication rates. Increasing experience with this technique can decrease rates of complications.

The expanding role of the endonasal endoscopic approach in pituitary and skull base surgery: A 2014 perspective

BACKGROUND

The past two decades have been the setting for remarkable advancement in endonasal endoscopic neurosurgery. Refinements in camera definition, surgical instrumentation, navigation, and surgical technique, including the dual surgeon team, have facilitated purely endonasal endoscopic approaches to the majority of the midline skull base that were previously difficult to access through the transsphenoidal microscopic approach.

METHODS

This review article looks at many of the articles from 2011 to 2014 citing endonasal endoscopic surgery with regard to approaches and reconstructive techniques, pathologies treated and outcomes, and new technologies under consideration.

RESULTS

Refinements in approach and closure techniques have reduced the risk of cerebrospinal fluid leak and infection. This has allowed surgeons to more aggressively treat a variety of pathologies. Four main pathologies with outcomes after treatment were identified for discussion: pituitary adenomas, craniopharyngiomas, anterior skull base meningiomas, and chordomas. Within all four of these tumor types, articles have demonstrated the efficacy, and in certain cases, the advantages over more traditional microscope-based techniques, of the endonasal endoscopic technique.

CONCLUSIONS

The endonasal endoscopic approach is a necessary tool in the modern skull base surgeon's armamentarium. Its efficacy for treatment of a wide variety of skull base pathologies has been repeatedly demonstrated. In the experienced surgeon's hands, this technique may offer the advantage of greater tumor removal with reduced overall complications over traditional craniotomies for select tumor pathologies centered near the midline skull base.