Celebrating the golden anniversary of anterior skull base surgery: reflections on the past 50 years and its historical evolution

Frontiers of Cranial Base Surgery: Integrating Technique, Technology, and Teamwork for the Future of Neurosurgery

The landscape of cranial base surgery has undergone monumental transformations over the past several decades. This article serves as a comprehensive survey, detailing both the historical and current techniques and technologies that have propelled this field into an era of unprecedented capabilities and sophistication. In the prologue, we traverse the historical evolution from rudimentary interventions to the state-of-the-art neurosurgical methodologies that define today's practice. Subsequent sections delve into the anatomical complexities of the anterior, middle, and posterior cranial fossa, shedding light on the intricacies that dictate surgical approaches. In a section dedicated to advanced techniques and modalities, we explore cutting-edge evolutions in minimally invasive procedures, pituitary surgery, and cranial base reconstruction. Here, we highlight the seamless integration of endocrinology, biomaterial science, and engineering into neurosurgical craftsmanship. The article emphasizes the paradigm shift towards "Functionally" Guided Surgery facilitated by intraoperative neuromonitoring. We explore its historical origins, current technologies, and its invaluable role in tailoring surgical interventions across diverse pathologies. Additionally, the digital era's contributions to cranial base surgery are examined. This includes breakthroughs in endoscopic technology, robotics, augmented reality, and the potential of machine learning and AI-assisted diagnostic and surgical planning. The discussion extends to radiosurgery and radiotherapy, focusing on the harmonization of precision and efficacy through advanced modalities such as Gamma Knife and CyberKnife. The article also evaluates newer protocols that optimize tumor control while preserving neural structures. In acknowledging the holistic nature of cranial base surgery, we advocate for an interdisciplinary approach. The ecosystem of this surgical field is presented as an amalgamation of various medical disciplines, including neurology, radiology, oncology, and rehabilitation, and is further enriched by insights from patient narratives and quality-of-life metrics. The epilogue contemplates future challenges and opportunities, pinpointing potential breakthroughs in stem cell research, regenerative medicine, and genomic tailoring. Ultimately, the article reaffirms the ethos of continuous learning, global collaboration, and patient-first principles, projecting an optimistic trajectory for the field of cranial base surgery in the coming decade.

Clinical effect of high-flow revascularization in microsurgery combined with endoscopic endonasal surgery for skull base tumors with intracranial and extracranial involvement

Background

The objective of the study is to investigate the surgical methods and clinical effects of high-flow revascularization in microsurgery combined with endoscopic endonasal surgery for skull base tumors with intracranial and extracranial involvement.

Methods

The relationships between skull base tumors and internal carotid artery (ICA), tumor location and size, and the extent of tumor invasion were assessed. Preoperative CT perfusion (CTP), magnetic resonance (MR) perfusion-weighted imaging (PWI) (MR-PWI), and digital subtraction angiography (DSA) were performed to evaluate collateral circulation and brain tissue perfusion. Then craniotomy through the fronto-orbitozygomatic approach was performed, based on which four cases received extended middle skull base approach+Dolenc approach + Fukushima bypass type I, and six cases received extended middle skull base approach+Fukushima bypass type III. After surgery, DSA, CT angiogram (CTA), and CTP/PWI were performed to evaluate the patency of the reconstructed vessels and cerebral perfusion, and contrast-enhanced MRI to evaluate the degree of tumor resection. All patients were followed up for 6-12 months.

Results

Among the 10 cases investigated, gross total resection was achieved in 8 cases, subtotal resection in 1 case, and partial resection in 1 case, as confirmed by CT and enhanced MRI. The patency of revascularization vessels was observed using fluorescein angiography during the operation in all patients and via DSA and CTA postoperatively in nine patients. One patient underwent ventilator-assisted ventilation because of respiratory failure and failed to undergo DSA and CTA. Regarding postoperative complications, one patient developed watershed cerebral infarction on the operated side but no sequelae after drug treatment, three patients developed facial numbness, which improved after 3 months, and two patients experienced worsened diplopia. After 6 to 12 months of follow-up on the nine evaluable patients, the Glasgow Outcome Scale (GOS) was 4-5 after surgery. In addition, 6-month follow-up results showed that one patient with clival chondrosarcoma developed recurrence on contrast-enhanced MRI, while no relapse was observed in the other patients.

Conclusion

For skull base tumors with intracranial and extracranial invasion and involving the ICA, revascularization might improve the total resection rate and reduce the recurrence rate and risk of intraoperative bleeding and postoperative ischemia.

The efficacy of function-preservation in treating paranasal sinus and nasal cavity neoplasms

Background

Craniofacial resection (CFR) has been regarded as the gold standard for paranasal sinus and nasal cavity (PNSNC) neoplasms. The improvement of surgical procedures has been ongoing in recent years. We analyzed the clinical curative effects of the function-preservation therapy that was mainly using nasal endoscopic surgery along with appropriate radiotherapy and chemotherapy as applicable.

Methods

We performed a retrospective analysis of factors that influence the survival time of the 28 patients with PNSNC neoplasms who underwent nasal endoscopic surgery. All patients with tumor lesions underwent a complete resection in en bloc or piecemeal resection. Five cases did not undergo radiotherapy or chemotherapy; the remaining 23 patients had multimodality therapy.

Results

The median follow-up time was 41.5 (range = 14-97) months. The overall 3-year survival rate was 78.57% for T3 cancer and 50% for those with T4. T classification (P = 0.031) and multimodality therapy (P = 0.038) were independent prognostic factors for postoperative 3-year survival rate of patients with PNSNC neoplasms.

Conclusion

Function-preservation therapy based on the minimally invasive endoscopic resection (MIER) with appropriate adjuvant therapy not only prolonged the overall survival time but also provided an opportunity to preserve organ function at the same time, which helped to improve the patients' quality of life.

The Application of Three-Dimensional Technology Combined With Image Navigation in Nasal Skull Base Surgery

Three-dimensional (3D) technology including 3D reconstruction and 3D printing technology, has been widely used in clinical treatment, especially in surgical planning, and image navigation technology, which can make surgical procedures more accurate, now is also increasingly favored by surgeons. But the combination of those 2 technologies was rarely reported. Thus, this study will preliminarily investigate the feasibility and the effect of the combination of 2 technologies in endonasal skull base surgery. Eight patients were involved in this study (from October 2016 to July 2017 at The Affiliated Hospital of Qingdao University), 5 cases of nasal skull base tumors and 3 cases of foreign body perforation. All operations were done under the assistance of 3D technology and image guidance system. Surgical discussion with patient, preoperative planning and clinical teaching were investigated between 2D images and 3D models by voting. For all cases, 3D reconstruction model and 3D printed model were deemed to be more helpful than CT/MRI images in surgical discussion with the patient; surgical simulation on 3D model in preoperative planning was largely deemed to be helpful and very helpful; and in clinical teaching, 3D models combined with image guidance system were deemed to be more helpful in understanding the disease than using 2D images. Besides, all patients recovered well after surgery, no recurrence and complications were found in the follow-up. The combination of 3D technology and electromagnetic image guidance system could improve surgical efficiency and the quality of clinical teaching.

Utility of early postoperative imaging after combined endoscopic and open ventral skull base surgery

PURPOSE

Immediate postoperative imaging is frequently obtained after combined skull base surgery (SBS) with endoscopic endonasal and open transcranial approaches. The importance of early postoperative imaging for detecting complications in these patients is still debatable. In this study, we investigated the clinical utility of early postoperative imaging after combined SBS for determination of postoperative complications.

METHODS

A retrospective chart analysis of 21 cases of combined SBS between 2009 and 2015 was performed. Data on postoperative computed tomography (CT) and magnetic resonance imaging (MRI), and the hospital course were collected. We separated interpretations of postoperative imaging into two groups: (1) when using the radiologist's interpretation alone, and (2) when using the surgeon's knowledge of the case in conjunction with imaging.

RESULTS

Forty-two postoperative scans were obtained (21 CT, 21 MRI) within 48 hours of surgery. There was a significant statistical difference between imaging interpretation by surgeons and radiologists for CT interpretation only. For CT interpretation the true positive (TP), false positive (FP), true negative (TN), and false negative (FN) rates for radiologists (TP, 0/21; FP, 6/21; TN, 11/21; FN, 4/21) slightly deviated from surgeons' interpretation (TP, 1/21 [p = 0.9999]; FP, 0/21 [p = 0.0207]; TN, 17/21 [p = 0.1000]; FN, 3/21 [p = 1.000]). Rates for MRI interpretation by both groups were nearly identical, with no significant difference found. Overall, four patients experienced seven postoperative complications, which led to a complication rate of 19.0% (4/21). The patients exhibited clinical symptoms in all instances of postoperative complications that required further intervention.

CONCLUSION

The benefit of early postoperative imaging to detect complications after combined SBS was limited. In this cohort of patients, positive imaging findings' effects on patient management were dictated by the presence of supporting clinical symptoms.

Management of Skull Base Defects After Surgical Resection of Sinonasal and Ventral Skull Base Malignancies

Over the past 2 decades, there has been a significant increase in the resection of larger and more complex ventral skull base malignancies. The resection of these lesions has resulted in the creation of larger and more difficult to repair skull base defects. There are many available options for ventral skull base reconstruction. Despite the variety of reconstructive options, the key objective is to eliminate any communication between the intracranial space and the sinonasal cavity. This article discusses some of the more common techniques currently used for repair of these skull base defects.

Minimally invasive endoscopic resection for the treatment of sinonasal malignancy: the outcomes and risk factors for recurrence

Purpose

The role of minimally invasive endoscopic resection (MIER) in the treatment of sinonasal malignancy is controversial. Herein, we performed a retrospective review of a large case series of sinonasal malignancy patients treated with MIER aimed at evaluating the outcomes and identifying the risk factors for recurrence.

Methods

Patients with sinonasal malignancy who underwent MIER from March 2000 to May 2015 were enrolled, and their clinical data were collected. The clinical outcomes were evaluated by determining the 5-year overall survival (OS) and disease-free survival (DFS). The predictive factors for survival and potential independent risk factors for recurrence were explored.

Results

A total of 120 patients were enrolled, including 62 males and 58 females. The mean follow-up period was 51.4 (95% confidence interval: 44.0–59.1) months. The most frequent histological type was mucosal malignant melanoma. The positive margin rate was 19.2% (23/120). Seventy-one patients had the safety anatomic plane (SAP). Age ≥50 years, nodal metastasis, and not having the SAP were found to be predictive factors for survival, and absence of SAP was found to be an independent risk factor for recurrence.

Conclusion

Our study indicated that MIER is an effective and safe surgical procedure in appropriately selected patients. Tumor resection with a safety anatomic boundary is likely to lead to improved survival and decreased recurrence. However, a larger sample and long-term prospective observation are still required to establish the role of MIER in treatment of sinonasal malignancy.

Variations of mucosal-sparing septectomy for endonasal approach to the craniocervical junction

OBJECTIVES/HYPOTHESIS

Recent advances in surgical techniques have rendered the craniocervical junction (CCJ) accessible transnasally. Endoscopic endonasal transclival and transodontoid approaches are routinely performed in leading skull base centers. Usually, these approaches involve a posterior bony and mucosal septectomy, which may compromise the vascularized pedicled nasoseptal flap (PNSF), a robust reconstructive option for repair of large skull base defects. With the possibility of an intraoperative cerebrospinal fluid leak and the reported success of the PNSF for repair of these defects, preserving the integrity of the PNSF is beneficial during the endoscopic endonasal approach to the CCJ. We describe three new variations/refinements of the endoscopic endonasal approach to the CCJ that preserve the mucosal integrity of the posterior nasal septum and PNSF.

METHODS

Photo and video documentation of cadaveric dissections.

RESULTS

The steps required for the different variations in approaching the CCJ are demonstrated. These three options are: 1) nonopposing Killian incisions with submucosal elevation of PNSFs laterally under the inferior turbinates (the PNSFs are retracted laterally and left attached superiorly onto the nasal septum and laterally under the inferior turbinate); 2) bilateral non-opposing PNSFs tucked beneath their respective middle turbinate or into the sphenoid sinus; and 3) a hybrid approach combining option 1 performed on one side and option 2 on the contralateral side. All three options allowed for a mucosal-sparing septectomy to provide ample access to the CCJ.

CONCLUSION

These variations/refinements of the mucosal-sparing approach to the CCJ allowed adequate surgical access with sufficient maneuverability while preserving both PNSFs.

LEVEL OF EVIDENCE

NA. Laryngoscope, 126:2220-2225, 2016.

Advantage of Extended Craniofacial Resection for Advanced Malignant Tumors of the Nasal Cavity and Paranasal Sinuses: Long-Term Outcome and Surgical Management

OBJECTIVE

Craniofacial resection (CFR) for advanced sinonasal malignant tumors (SNMTs) is mandatory for radical resection. Surgeons must be aware of perioperative complications and long-term outcome because this procedure is extremely invasive, especially when the tumor involves the anterior skull base.

METHODS

Thirty-eight consecutive surgical patients with advanced SNMT of T4 stage or Kadish stage C (31 men and 7 women; mean age, 55 years; range: 19-76 years) treated with CFR in the past 28 years were followed up for 59.4 months. In cases of unilateral orbital extension, en-bloc resection was achieved using several neurosurgical techniques (extended CFR) from 2005 onwards. Herein, we evaluated the safety and effectiveness of surgery by comparing survival data between 2 time periods (first stage: 1984-2004, second stage: 2005-2012).

RESULTS

Squamous cell carcinoma was the most common histological type observed (65.8%), followed by esthesioneuroblastoma (15.8%). Using a combination of adjuvant radiation therapy, the 5-year overall survival and the 5-year disease-specific survival rates were 55.5% and 59.4%, respectively. Sarcomatous histology was a poor prognostic factor. The 5-year disease-specific survival rate was 48.9% in the first stage and improved to 82.1% in the second stage (P = 0.057); this was related to improvements in local control rate.

CONCLUSIONS

CFR and postoperative radiotherapy are safe and effective for treating advanced SNMTs. Extended CFR, including radical orbital exenteration, may contribute to good long-term outcomes. A diverse surgical team may help perform radical resection and reconstruction in patients with advanced tumors.

Monitor height ergonomics: A comparison of operating room video display terminals

A surgeon's eyes should be positioned 1 meter (m) distant and no more than 15° below the top of an operating monitor (0.27 m). We sought to determine which operating room video display terminal can best accommodate ergonomically optimized gaze during surgery. Floor to eye height was measured for surgeons in seated, perched, and standing positions. These ranges were then compared to vertical displacement ranges for monitors measured from floor to top of the screen. Eye height was measured for standing (1.56-1.80 m), perched (1.40-1.65 m), and seated (1.10-1.32 m) positions. The minimum distance (min) between the floor and the top of the monitor and the vertical mobility range (VR) of the monitor were measured throughout a tertiary medical center including towers with boom arms (TcB) (min: 1.58 m, VR: 0.37 m), towers without booms (TsB) (min: 1.82 m, VR: 0.025 m), ceiling mounted booms (CMB) (min: 1.34 m:, VR: 1.04 m), and portable monitors (PM) (min: 1.73 m, VR: 0.04 m). The tangent of 15° declination was used to calculate a correction factor to determine the minimum optimal ergonomic display height. The correction factor was subtracted from the eye height at each position to determine the lowest target height and the highest target floor to eye distance for each position. Analysis of variance with least significant difference post hoc testing identified all minimum distances and vertical ranges to be statistically different (p < 0.001). Monitor vertical displacement varied between styles of carts. CMB video display terminal systems can accommodate standing, perched and the tallest seated surgeons. TcB, TsB and PM systems cannot adequately accommodate all standing, perched or seated surgeons.

Anterior skull-base surgery: current opinion

PURPOSE OF REVIEW

The field of anterior skull-base surgery has undergone rapid advancement in the last 10-15 years. As a result, tumors of the anterior skull base that were once considered inoperable are now routinely resected with reliable results and decreasing morbidity. The purpose of this review is to highlight the most up-to-date opinions and advancements within the field, and to evaluate the recent advances in the surgical management of anterior skull-base tumors.

RECENT FINDINGS

In the last year, the body of literature in anterior skull-base surgery has been expanded with new anatomic insights, surgical techniques, and data on patient outcomes and quality of life. Much of this literature is focused on minimally invasive, endoscopic techniques, which have expanded greatly in the last decade.

SUMMARY

This article summarizes the most current opinion in the field of anterior skull-base surgery. Recent literature regarding new anatomic insights, surgical techniques (resection and reconstruction), and outcomes data are outlined.

Schwannomas of the sinonasal tract and anterior skull base: a systematic review of 94 cases

BACKGROUND

Schwannomas of the anterior skull base (ASB) and sinonasal tract are extremely rare. These lesions mimic other pathologies such as olfactory groove meningiomas, hemangiopericytomas, and esthesioneuroblastomas. Because of their low incidence, ASB and sinonasal tract schwannomas have not been well characterized. A systematic review of ASB and sinonasal tract schwannomas was conducted to further elucidate the presentation and surgical management of these lesions.

METHODS

A MEDLINE/PubMed search was performed, identifying 71 articles representing 94 cases of ASB and sinonasal schwannomas. Each case was analyzed for demographics, clinical presentation, anatomic location, radiographic features, and surgical treatment.

RESULTS

In 94 patients with ASB and sinonasal schwannomas, 44 (46.8%) were exclusively sinonasal, 30 cases (31.9%) were exclusively intracranial, 12 (12.8%) were primarily intracranial with extension into the paranasal sinuses, and 8 (8.5%) were primarily sinonasal with intracranial extension. Headaches and nasal obstruction were the most common presenting symptoms occurring in 30.9 and 29.8% of cases, respectively. Magnetic resonance imaging typically showed a hyperintense mass on T2-weighted imaging (70%) and hypointense (41%) on T1-weighted imaging. Most patients underwent surgical gross total resection via craniotomy, endoscopic endonasal approach, rhinotomy, or other sinonasal approaches. Recurrence occurred in three cases ranging from 4 months to 13 years. Postoperative complications included cerebral spinal fluid leakage, bacterial meningitis, epidural hematoma, and pneumocranium.

CONCLUSION

ASB and sinonasal schwannomas are rare lesions and should be considered in the differential diagnosis of ASB masses involving the cribriform plate with sinonasal extension. Gross total resection of these lesions should be considered the goal of operative management.

Immediate postoperative imaging after uncomplicated endoscopic approach to the anterior skull base: is it necessary?

BACKGROUND

Postoperative imaging is frequently performed to assess for intracranial complications following anterior skull base (ASB) surgery. However, there is little data to suggest that radiologic studies change the management of complications. In this study, the utility of postoperative imaging within 72 hours after uncomplicated ASB surgery was examined.

METHODS

A retrospective review was conducted of 143 patients who underwent endoscopic ASB surgery between 2007 and 2013 at Loyola University Medical Center. The main outcomes measures included the ability of head computed tomography (CT) scan to identify postoperative complications and hallmark symptoms associated with complications.

RESULTS

Seventy-nine patients underwent postoperative imaging within 72 hours of the initial surgery. The most common finding was pneumocephalus (35/79; 44%). Expanding pneumocephalus requiring surgical intervention developed in 3 cases. Cerebrospinal fluid (CSF) leak was the most common complication, occurring in 22 of 143 (15%) of the patients. Of the 24 patients who developed a postoperative complication, all had clinical signs or symptoms indicative of the need for surgical or medical intervention. The positive predictive value for a head CT scan to detect a complication was 12%, negative predictive value was 92%, and sensitivity and specificity were 63% and 48%, respectively.

CONCLUSION

Routine postoperative imaging may be unnecessary after uncomplicated endoscopic ASB surgery because (1) it may not alter patient management; (2) it may not detect the most common complication (CSF leak); and (3) when imaging is positive, the patient has clinical symptoms suggesting a need for intervention.

Subcranial craniotomy approach for frontobasal fracture correction

OBJECTIVE

Frontobasilar fracture types and the outcome of patients after management with the subcranial approach technique were evaluated.

MATERIAL AND METHODS

A retrospective analysis of 48 patients (45 males, mean age 38,5 years; range 16-82 years) who had a subcranial approach for frontal base fracture correction between April 1996 and April 2011 at a tertiary care academic hospital in Turku, Finland.

RESULTS

Sixteen (33%) patients had fractures including all frontobasilar fracture types (Type I-IV) i.e. fractures that involved frontal sinuses, orbital roofs, ethmoidal region, cribriform plate and sphenoidal region. Twenty-seven (56%) patients were considered to have had brain damage at presentation. Forty percent of patients were suffering from synchronous trauma. Peroperatively, 31 (65%) patients had exposure or defect of the dura due to bone dehiscence but only two patients suffered from cerebrospinal fluid (CSF) fistula following surgery. CSF fistulae were covered by pericranium in most of the cases (68%). There was no postoperative meningitis. Thirty-eight percent of the patients needed further operation with a subcranial craniotomy following primary reconstruction. At the last follow-up visit 35% were suffering from permanent neurological problems following brain injury.

CONCLUSIONS

Subcranial approach seemed successful in the management of all frontobasilar fractures in this series with reasonably low complication rate. Therefore, we would recommend it as the technique of choice in multiple and even in the most complicated frontal base fractures.

Modified subtotal-Lothrop procedure for extended frontal sinus and anterior skull-base access: a case series

BACKGROUND

The endoscopic modified Lothrop procedure (EMLP) is well established for resistant frontal sinus disease and anterior skull base (ASB) exposure. However, this technique may be unnecessarily aggressive by removing avoidable sinonasal structures in select cases. Previously, in a cadaveric study, we proposed a modification of the EMLP, termed the modified subtotal-Lothrop procedure (MSLP), to access the ASB and to address complex frontal sinus disease, for which access to the bilateral frontal sinus posterior table is required. This study provides a step-by-step description of this technique, and presents our experience in 5 patients who underwent this approach.

METHODS

A retrospective analysis was performed at a tertiary referral center on all patients undergoing endoscopic ASB resection and complex frontal sinus surgeries between May 2011 and May 2013. Of 8 patients identified who underwent an MSLP, 5 had at least 1-year follow-up.

RESULTS

All patients underwent successful ASB exposure via the MSLP without complications and preservation of one frontal sinus recess. Adequate access to the bilateral posterior frontal sinus table was achieved in all cases. A patent frontal sinus drainage pathway could be assessed endoscopically after a mean follow-up of 18.6 (range, 12-27) months.

CONCLUSION

The MSLP is a feasible approach for exposure of the ASB and accessing complex frontal sinus pathology. This modification provides adequate ASB exposure and surgical maneuverability similar to the EMLP, while preserving one frontal sinus recess. This modification was successful in providing adequate exposure and maneuverability as well as maintaining frontal sinus patency in this small cohort.

Endoscopic endonasal technique: treatment of paranasal and anterior skull base malignancies

Objective

Method

Conclusion

Assessment of mucocele formation after endoscopic nasoseptal flap reconstruction of skull base defects

Advances in endoscopic skull base (SB) surgery have led to the resection of increasingly larger cranial base lesions, resulting in large SB defects. These defects have initially led to increased postoperative cerebrospinal fluid (CSF) leaks. The development of the vascularized pedicled nasoseptal flap (PNSF) has successfully reduced postoperative CSF leaks. Mucocele formation, however, has been reported as a complication of this technique. In this study, we analyze the incidence of mucocele formation after repair of SB defects using a PNSF. A retrospective review was performed from December 2008 to December 2011 to identify patients who underwent PNSF reconstruction for large ventral SB defects. Demographic data, defect site, incidence of postoperative CSF leaks, and rate of mucocele formation were collected. Seventy patients undergoing PNSF repair of SB defects were identified. No postoperative mucocele formation was noted at an average radiological follow-up of 11.7 months (range, 3–36.9 months) and clinical follow-up of 13.8 months (range, 3–38.9 months), making the overall mucocele rate 0%. The postoperative CSF leak rate was 2.9%. Proper closure of SB defects is crucial to prevent CSF leaks. The PNSF is an efficient technique for these repairs. Although this flap may carry an inherent risk of mucocele formation when placed over mucosalized bone during repair, we found that meticulous and strategic removal of mucosa from the site of flap placement resulted in a 0% incidence of postoperative mucocele formation in our cohort.

Early harvesting of the vascularized pedicled nasoseptal flap during endoscopic skull base surgery

PURPOSE

The vascularized pedicled nasoseptal flap (PNSF) represents a successful option for reconstruction of large skull base defects after expanded endoscopic endonasal approaches (EEA). This vascularized flap can be harvested early or late in the operation depending on the anticipation of high-flow CSF leaks. Each harvesting technique (early vs. late) is associated with different advantages and disadvantages. In this study, we evaluate our experience with early harvesting of the PNSF for repair of large skull base defects after EEA.

METHODS

A retrospective review was performed at a tertiary care medical center on patients who underwent early PNSF harvesting during reconstruction of intraoperative high-flow CSF leaks after EEA between December 2008 and March 2012. Demographic data, repair materials, surgical approach, and incidence of PNSF usage were collected.

RESULTS

Eighty-seven patients meeting the inclusion criteria were identified. In 86 procedures (98.9%), the PNSF harvested at the beginning of the operation was used. In 1 case (1.1%), the PNSF was not used because a high-flow intraoperative CSF leak was not encountered. This patient had recurrence of intradural disease 8months later, and the previously elevated PNSF was subsequent used after tumor resection.

CONCLUSION

Based on our data, a high-flow CSF leak and need for a PNSF can be accurately anticipated in patients undergoing EEA for skull base lesions. Because of the advantages of early harvesting of the PNSF and the high preoperative predictive value of CSF leak anticipations, this technique represents a feasible harvesting practice for EEA surgeries.