Case-specific protocol to reduce cerebrospinal fluid leakage after endonasal endoscopic surgery

Learning curve for the transsphenoidal endoscopic endonasal approach to pituitary tumors

INTRODUCTION

The transsphenoidal endoscopic approach is a relatively new procedure compared to the microscopic approach in pituitary adenoma resection. The endoscopic approach has shown to significantly decrease the rate of complications, time in the operating room and hospital, and patient post-op discomfort. However, this procedure requires the surgeon to make use of different visual and tactile clues that must be developed with experience. Therefore, it is important to understand the learning curve that the surgeon must overcome to become proficient with the endoscopic approach.

METHODS

Retrospective review of a single-surgeon consecutive series of 78 patients undergoing endoscopic pituitary tumor surgery from 2006 to 2012 at Rush University Medical Center has been used in this study. Patients were grouped according to an early (n = 9) and late group (n = 68) determined by a significant difference in outcomes. Our primary outcome measures were: duration of operation, CSF leak, hospital length of stay, visual field improvement, diabetes insipidus, panhypopituitarism, and subtotal resection.

RESULTS

There was a significant reduction in OR time and intraoperative CSF leaks between the early and late groups. There was no difference in hospital LOS or visual field improvement between the groups. With regards to complication rates, there was no difference found for DI, panhypopituitarism, lumbar drain placement, sinusitis, or subtotal resection between the two groups.

CONCLUSION

This study indicates that there may be a learning curve of approximately 9 cases before a surgical team can decrease OR times and reduce the rate of intraoperative CSF leaks for the endonasal endoscopic approach to pituitary adenoma resection.

Endonasal endoscopic reoperation for residual or recurrent craniopharyngiomas

OBJECTIVE Craniopharyngiomas can be difficult to remove completely based on their intimate relationship with surrounding visual and endocrine structures. Reoperations are not uncommon but have been associated with higher rates of complications and lower extents of resection. So radiation is often offered as an alternative to reoperation. The endonasal endoscopic transsphenoidal approach has been used in recent years for craniopharyngiomas previously removed with craniotomy. The impact of this approach on reoperations has not been widely investigated. METHODS The authors reviewed a prospectively acquired database of endonasal endoscopic resections of craniopharyngiomas over 11 years at Weill Cornell Medical College, NewYork-Presbyterian Hospital, performed by the senior authors. Reoperations were separated from first operations. Pre- and postoperative visual and endocrine function, tumor size, body mass index (BMI), quality of life (QOL), extent of resection (EOR), impact of prior radiation, and complications were compared between groups. EOR was divided into gross-total resection (GTR, 100%), near-total resection (NTR, > 95%), and subtotal resection (STR, < 95%). Univariate and multivariate analyses were performed. RESULTS Of the total 57 endonasal surgical procedures, 22 (39%) were reoperations. First-time operations and reoperations did not differ in tumor volume, radiological configuration, or patients' BMI. Hypopituitarism and diabetes insipidus (DI) were more common before reoperations (82% and 55%, respectively) compared with first operations (60% and 8.6%, respectively; p < 0.001). For the 46 patients in whom GTR was intended, rates of GTR and GTR+NTR were not significantly different between first operations (90% and 97%, respectively) and reoperations (80% and 100%, respectively). For reoperations, prior radiation and larger tumor volume had lower rates of GTR. Vision improved equally in first operations (80%) compared with reoperations (73%). New anterior pituitary deficits were more common in first operations compared with reoperations (51% vs 23%, respectively; p = 0.08), while new DI was more common in reoperations compared with first-time operations (80% vs 47%, respectively; p = 0.08). Nonendocrine complications occurred in 2 (3.6%) first-time operations and no reoperations. Tumor regrowth occurred in 6 patients (11%) over a median follow-up of 46 months and was not different between first versus reoperations, but was associated with STR (33%) compared with GTR+NTR (4%; p = 0.02) and with not receiving radiation after STR (67% vs 22%; p = 0.08). The overall BMI increased significantly from 28.7 to 34.8 kg/m² over 10 years. Six months after surgery, there was a significant improvement in QOL, which was similar between first-time operations and reoperations, and negatively correlated with STR. CONCLUSIONS Endonasal endoscopic transsphenoidal reoperation results in similar EOR, visual outcome, and improvement in QOL as first-time operations, with no significant increase in complications. EOR is more impacted by tumor volume and prior radiation. Reoperations should be offered to patients with recurrent craniopharyngiomas and may be preferable to radiation in patients in whom GTR or NTR can be achieved.

Endoscopic Endonasal Repair of Spontaneous and Traumatic Cerebrospinal Fluid Rhinorrhea: A Review and Local Experience

This article presents an overview of endoscopic endonasal repair of cerebrospinal fluid (CSF) rhinorrhea. In recent years, endoscopic repair has become the standard of care for managing this condition, because it gradually replaces the traditional open transcranial approach. Discussion includes the etiologic classification of CSF rhinorrhea, management paradigm for each category, diagnosis algorithm, comprehensive description of the surgical technique, and an updated review of the literature regarding the safety and efficacy of this procedure. In addition, the authors present their experience, including 2 surgical videos demonstrating endoscopic repair of CSF rhinorrhea in 2 distinct clinical scenarios.

Extended endoscopic endonasal transsphenoidal approach for retrochiasmatic craniopharyngioma: Surgical technique and results

Objective:

Surgical treatment of retrochiasmatic craniopharyngioma still remains a challenge. While complete removal of the tumor with preservation of the vital neurovascular structures is often the goal of the treatment, there is no optimal surgical approach available to achieve this goal. Transcranial and transsphenoidal microsurgical approaches, commonly used in the past, have considerable technical limitations. The extended endonasal endoscopic surgical route, obtained by removal of tuberculum sellae and planum sphenoidale, offers direct midline access to the retrochiasmatic space and provides excellent visualization of the undersurface of the optic chiasm. In this report, we describe the technical details of the extended endoscopic approach, and review our results using this approach in the surgical management of retrochiasmatic craniopharyngiomas.

Methods:

Fifteen children, including 9 girls and 6 boys, aged 8 to 15 years underwent surgery using extended endoscopic transsphenoidal approach between 2008 and 2014. Nine patients had a surgical procedure done previously and presented with recurrence of symptoms and regrowth of their residual tumors.

Results:

A gross total or near total excision was achieved in 10 (66.7%) patients, subtotal resection in 4 (26.7%), and partial removal in 1 (6.7%) patient. Postoperatively, headache improved in 93.3%, vision recovered in 77.3%, and the hormonal levels stabilised in 66.6%. Three patients (20%) developed postoperative CSF leaks which were managed conservatively. Three (20%) patients with diabetes insipidus and 2 (13.3%) with panhypopituitarism required long-term hormonal replacement therapy.

Conclusions:

Our early experience suggests that the extended endonasal endoscopic approach is a reasonable option for removal of the retrochiasmal craniopharyngiomas. Compared to other surgical approaches, it provides better opportunities for greater tumor removal and visual improvement without any increase in risks.

Sensitivity and specificity of intrathecal fluorescein and white light excitation for detecting intraoperative cerebrospinal fluid leak in endoscopic skull base surgery: a prospective study

OBJECT

The intraoperative detection of CSF leaks during endonasal endoscopic skull base surgery is critical to preventing postoperative CSF leaks. Intrathecal fluorescein (ITF) has been used at varying doses to aid in the detection of intraoperative CSF leaks. However, the sensitivity and specificity of ITF at certain dosages is unknown.

METHODS

A prospective database of all endoscopic endonasal procedures was reviewed. All patients received 25 mg ITF diluted in 10 ml CSF and were pretreated with dexamethasone and Benadryl. Immediately after surgery, the operating surgeon prospectively noted if there was an intraoperative CSF leak and fluorescein was identified. The sensitivity, specificity, and positive and negative predictive power of ITF for detecting intraoperative CSF leak were calculated. Factors correlating with postoperative CSF leak were determined.

RESULTS

Of 419 patients, 35.8% of patients did not show a CSF leak. Fluorescein-tinted CSF (true positive) was noted in 59.7% of patients and 0 false positives were encountered. CSF without fluorescein staining (false negative) was noted in 4.5% of patients. The sensitivity and specificity of ITF were 92.9% and 100%, respectively. The negative and positive predictive values were 88.8% and 100%, respectively. Postoperative CSF leaks only occurred in true positives at a rate of 2.8%.

CONCLUSIONS

ITF is extremely specific and very sensitive for detecting intraoperative CSF leaks. Although false negatives can occur, these patients do not appear to be at risk for postoperative CSF leak. The use of ITF may help surgeons prevent postoperative CSF leaks by intraoperatively detecting and confirming a watertight repair.

Principles in Skull Base Reconstruction following Expanded Endoscopic Approaches

OBJECTIVES

This study aims to describe the types of anterior skull base defects following expanded endoscopic approaches (EEA) and to outline the techniques involved in the repair of these defects.

DESIGN

We retrospectively analyzed 63 cases of endoscopic skull base reconstruction (ESBR) following tumor excision, done from September 2011 to January 2015. These tumors consisted of 14 pituitary adenomas, 20 craniopharyngiomas, and 29 other miscellaneous tumors. The classification of skull base defects by Tabaee et al and the classification of cerebrospinal fluid (CSF) leaks by Esposito et al were considered during the ESBR. Recurrence of CSF leak was considered as failure of reconstruction.

RESULTS

The 63 skull base defects included in this study occurred following EEA for tumor excision. Failure of reconstruction occurred in 6 six patients. All were successfully repaired, however, three patients in this series died due to tumor-related complications.

CONCLUSION

The adherence to the general principles of reconstruction, appreciating the subtle differences in the nature of the various defects and the ability to adopt different strategies are the prerequisites for the successful closure of skull base defects.

Endoscopic Endonasal Reconstruction of Skull Base: Repair Protocol

Background Endoscopic endonasal skull base reconstructions have been associated with postoperative cerebrospinal fluid (CSF) leaks. Objective A repair protocol for endoscopic endonasal skull base reconstruction is presented with the objective of decreasing the overall leak rate. Methods A total of 180 endoscopic endonasal skull base reconstructions were reviewed. Reconstructions were classified I to IV according to the reconstruction method, determined by severity of intraoperatively encountered CSF leaks for types I to III, and planned preoperatively for type IVs, which required nasoseptal flap. Results A total of 11 patients(6%) had postoperative leaks: 0 in type I (0%), 2 in type II (5%), 7 in type III (18%), and 2 (4%) in type IV reconstruction. Type III leak rate was higher than all other reconstructions. Total 31 intraoperative and 16 postoperative lumbar drains were placed. More patients had lumbar drains placed postoperatively for type III and intraoperatively for type IV than all other groups. There were significant overall differences in postoperative CSF leaks and lumbar drain placement between the four reconstruction types. No patient with type III reconstruction and intraoperative lumbar drain had postoperative CSF leak. Conclusions A repair protocol for endoscopic endonasal reconstructions determined by intraoperative CSF leak and preoperative planning minimizes unnecessary repair materials and additional morbidity. Our experience leads to a routine prophylactic lumbar drain placement in all type III leak and reconstructions. We also favor the type III reconstruction for minor intraoperative leaks, and a more generous use of type IV reconstructions in expectation of significant intraoperative CSF leak. The option of rescue flap technique in type III leaks should be strongly considered.

Preservation of Pituitary Function after Endonasal Craniopharyngioma Surgery: Case Report and Review of the Literature

Craniopharyngiomas comprise approximately 3% of all intracranial tumors. Preservation of pituitary function after resection represents a significant challenge due to their location in the anterior skull base and aggressive local behavior. We report a case of a 79-year-old woman with a large suprasellar craniopharyngioma who presented with visual loss. MRI revealed a suprasellar cystic mass with mass effect on the optic chiasm and pituitary gland. Following endoscopic endonasal gross total resection of the tumor, the patient’s pituitary function returned to normal. 

Endoscopic Endonasal Management of Metastatic Lesions of the Anterior Skull Base: Case Series and Literature Review

BACKGROUND

The anterior skull base is an uncommon site for brain metastases. A limited number of cases have been reported where a region of the skull base is accessed through an expanded/extended transsphenoidal route. In addition, reports of overall and progression-free survival rates are lacking.

OBJECTIVE

To report progression-free and overall survival rates for skull base metastases treated with aggressive endoscopic endonasal surgery and radiation therapy.

METHODS

We retrospectively review a prospective database of patients at New York Presbyterian Hospital undergoing expanded endoscopic endonasal surgery from 2004 to 2014. From this database, we identified all patients whose final pathology revealed a metastatic lesion in the midline skull base.

RESULTS

Seven hundred forty-nine patients underwent endonasal endoscopic surgery. Final pathology in 12 patients (1.6%) revealed metastasis to the sellar or parasellar region. Tumors were located in the sella, suprasellar cistern, clivus, ethmoid sinuses, sphenoid sinus, cavernous sinus, and craniovertebral junction. Breast and lung cancers were the most common primary diagnoses. Gross total resection was achieved in 41.6% of patients. There were no postoperative cerebrospinal fluid leaks. Adjuvant radiation therapy was used in 92% of cases. Median follow-up was 14 months (range, 1-55). Median progression-free and overall survival were 18 and 16 months, respectively.

CONCLUSIONS

The range of anterior skull base metastatic lesions that can be managed endonasally has increased with the advent of extended endonasal endoscopic surgical approaches. Favorable results can be obtained with this surgical approach as part of the overall management paradigm for patients with skull base metastases.

Endoscopic extended transsphenoidal resection of craniopharyngiomas: nuances of neurosurgical technique

Endoscopic approaches to the midline ventral skull base have been extensively developed and refined for resection of cranial base tumors over the past several years. As these techniques have improved, both the degree of resection and complication rates have proven comparable to those for transcranial approaches, while visual outcomes may be better via endoscopic endonasal surgery and hospital stays and recovery times are often shorter. Yet for all of the progress made, the steep learning curve associated with these techniques has hampered more widespread implementation and adoption. The authors address this obstacle by coupling a thorough description of the technical nuances for endoscopic endonasal craniopharyngioma resection with detailed illustrations of the important steps in the operation. Traditionally, transsphendoidal approaches to craniopharyngiomas have been restricted to lesions mostly confined to the sella. However, recently, endoscopic endonasal resections are more frequently employed for extrasellar and purely third ventricle craniopharyngiomas, whose typical retrochiasmatic location makes them ideal candidates for endoscopic transnasal surgery. The endonasal endoscopic approach offers many advantages, including direct access to the long axis of the tumor, early tumor debulking with minimal manipulation of the optic apparatus, more precise visualization of tumor planes, particularly along the undersurface of the chiasm and the roof of the third ventricle, and a minimal-access corridor that obviates the need for brain retraction. Although much emphasis has been placed on technical tenets of exposure and "how to get there," this article focuses on nuances of tumor resection "when you are there." Three operative videos illustrate our discussion of technical tenets.

Surgical management of trigeminal schwannomas: defining the role for endoscopic endonasal approaches

OBJECT

Because multiple anatomical compartments are involved, the surgical management of trigeminal schwannomas requires a spectrum of cranial base approaches. The endoscopic endonasal approach to Meckel's cave provides a minimal access corridor for surgery, but few reports have assessed outcomes of the procedure or provided guidelines for case selection.

METHODS

A prospectively acquired database of 680 endoscopic endonasal cases was queried for trigeminal schwannoma cases. Clinical charts, radiographic images, and long-term outcomes were reviewed to determine outcome and success in removing tumor from each compartment traversed by the trigeminal nerve.

RESULTS

Four patients had undergone endoscopic resection of trigeminal schwannomas via the transpterygoid approach (mean follow-up 37 months). All patients had disease within Meckel's cave, and 1 patient had extension into the posterior fossa. Gross-total resection was achieved in 3 patients whose tumors were purely extracranial. One patient with combined Meckel's cave and posterior fossa tumor had complete resection of the extracranial disease and 52% resection of the posterior fossa disease. One patient with posterior fossa disease experienced a sixth cranial nerve palsy in addition to a corneal keratopathy from worsened trigeminal neuropathy. There were no CSF leaks. Over the course of the study, 1 patient with subtotal resection required subsequent stereotactic radiosurgery for disease progression within the posterior fossa.

CONCLUSIONS

Endoscopic endonasal approaches appear to be well suited for trigeminal schwannomas restricted to Meckel's cave and/or extracranial segments of the nerve. Lateral transcranial skull base approaches should be considered for patients with posterior fossa disease. Further multiinstitutional studies will be necessary for adequate power to help determine relative indications between endoscopic and transcranial skull base approaches.

Endoscopic Endonasal Resection of Trigeminal Schwannomas

The surgical management of trigeminal schwannomas (TNs) entails the use of a variety of cranial base approaches for their effective surgical management. Although an extended middle fossa or posterior petrosal approach may be more appropriate for disease with primarily posterior fossa involvement, the expanded endoscopic approaches are suited for tumors with predominately middle fossa and/or extracranial involvement along the V2 and V3 divisions and limited posterior fossa extension. The endoscopic endonasal resection of TNs within the middle fossa, pterygopalatine fossa, and infratemporal fossa is reviewed in this article with a brief discussion of reported outcomes.

Long-term quality of life after endonasal endoscopic resection of adult craniopharyngiomas

OBJECT

Craniopharyngiomas are benign parasellar tumors for which surgical removal, although potentially curative, often leads to morbidity with resulting decreases in quality of life (QOL). The endonasal endoscopic approach is a minimal-access technique for removing these tumors and may reduce postoperative morbidity. The QOL following this method for resection of craniopharyngiomas has not been documented.

METHODS

The authors reviewed a database of consecutive endonasal endoscopic surgeries done at Weill Cornell Medical College. Adult patients with histologically proven craniopharyngiomas were included who had completed either only postoperative (> 9 months) or both pre- and postoperative QOL forms, the Anterior Skull Base Quality of Life (ASBQ) questionnaire, and the 22-Item Sinonasal Outcome Test (SNOT-22). Rates of gross-total resection (GTR), complications, and visual and endocrine function were collected. Retrospective independence (Wen score) was also assigned. A contemporaneous group of patients undergoing endonasal endoscopic pituitary macroadenoma resection was used as a control.

RESULTS

This study included 33 procedures performed in 31 patients. The average postoperative ASBQ score was 3.35 and the SNOT-22 score was 19.6. Better QOL was associated with GTR and postoperative radiation. Worse QOL was associated with persistent visual defects, hypopituitarism, tumor recurrence, increase in body mass index, and worsening Wen score. In a subset of 10 patients, both pre- and postoperative (> 9 months) QOL scores were obtained. Both ASBQ and SNOT-22 scores showed stability and a trend toward improvement, from 2.93 ± 0.51 to 2.96 ± 0.47 (ASBQ) and 23.7 ± 10.8 to 18.4 ± 11.6 (SNOT-22). Compared with 62 patients undergoing endoscopic pituitary macroadenoma resection, patients with craniopharyngiomas had worse postoperative QOL on the ASBQ (3.35 vs 3.80; p = 0.023) and SNOT-22 (19.6 vs 13.4; p = 0.12).

CONCLUSIONS

This report of validated site-specific QOL following endoscopic surgery for craniopharyngiomas shows an overall maintenance of postoperative compared with preoperative QOL. Better QOL could be seen in patients with GTR and radiation therapy, and worse QOL was found in patients with visual or endocrine deficits. Nevertheless, patients with craniopharyngiomas still had worse QOL than those undergoing similar surgery for pituitary macroadenomas, confirming the worse prognosis of craniopharyngiomas even when removed via a minimally invasive approach. These measures should serve as benchmarks for comparison with open transcranial approaches to similar tumors.

Fascia patchwork closure for endoscopic endonasal skull base surgery

With the development of endoscopic technology and surgery, resection of midline skull base tumors has been achieved using endoscopic endonasal skull base (EESB) approaches. EESB approaches reportedly have a greater risk of postoperative cerebrospinal fluid (CSF) leakage. Recently, the introduction of the nasoseptal flap (NSF) decreased dramatically the incidence of CSF leakage, but the use of an NSF increases the risk of disturbing the function of the nose. Here, we report our new technique called "fascia patchwork closure" for closure after EESB surgery and its outcome. All 48 cases involved midline skull base tumors resected via EESB approaches. Of them, 32 cases were closed by the fascia patchwork technique after tumor resection, and there was no incidence of CSF leakage. Moreover, 6 of the 32 cases were closed without the use of an NSF, indicating that the fascia patchwork closure approach is effective as part of a multilayer closure for the prevention of CSF leakage. The establishment and popularization of this technique might result in the further development of EESB surgery and also an improvement of postoperative nasal function.

Primary sphenoid sinus meningioma resection via transnasal transsphenoid approach: a case report

Meningiomas are slow-growing benign lesions that constitute ∼ 25% of primary intracranial tumours. Extracranial meningioma of the sphenoid sinus is extremely rare and may arise from ectopic arachnoid nests left behind during embryonic development. We present the case of a 61-year-old woman with left oculomotor nerve paralysis. Magnetic resonance imaging (MRI) revealed a 43 × 31 × 33 mm mass in the sphenoid sinus invading anteriorly into the posterior ethmoid sinus and superiorly into the base of the anterior cranial fossa. Microscopic transnasal transsphenoidal surgery was performed with multilayer reconstruction to the cranial base. Postoperative MRI confirmed total resection and recovery was uneventful. The pathological diagnosis was grade I meningothelial meningioma. Meningioma should be included in the differential diagnosis of sphenoid sinus mass. Surgery is the first-choice treatment and a transnasal transphenoidal approach is recommended. Cranial base reconstruction is important to avoid postoperative cerebrospinal fluid leakage.

Endoscopic endonasal skull base surgery: advantages, limitations, and our techniques to overcome cerebrospinal fluid leakage: technical note

In recent years, resections of midline skull base tumors have been conducted using endoscopic endonasal skull base (EESB) approaches. Nevertheless, many surgeons reported that cerebrospinal fluid (CSF) leakage is still a major complication of these approaches. Here, we report the results of our 42 EESB surgeries and discuss the advantages and limits of this approach for resecting various types of tumors, and also report our technique to overcome CSF leakage. All 42 cases involved midline skull base tumors resected using the EESB technique. Dural incisions were closed using nasoseptal flaps and fascia patch inlay sutures. Total removal of the tumor was accomplished in seven pituitary adenomas (33.3%), five craniopharyngiomas (62.5%), five tuberculum sellae meningiomas (83.3%), three clival chordomas (100%), and one suprasellar ependymoma. Residual regions included the cavernous sinus, the outside of the intracranial part of the internal carotid artery, the lower lateral part of the posterior clivus, and the posterior pituitary stalk. Overall incidence of CSF leakage was 7.1%. Even though the versatility of the approach is limited, EESB surgery has many advantages compared to the transcranial approach for managing mid-line skull base lesions. To avoid CSF leakage, surgeons should have skills and techniques for complete closure, including use of the nasoseptal flap and fascia patch inlay techniques.

Pneumocephalus patterns following endonasal endoscopic skull base surgery as predictors of postoperative CSF leaks

OBJECTIVES

Postoperative pneumocephalus is a common occurrence after endoscopic endonasal skull base surgery (ESBS). The risk of cerebrospinal fluid (CSF) leaks can be high and the presence of postoperative pneumocephalus associated with serosanguineous nasal drainage may raise suspicion for a CSF leak. The authors hypothesized that specific patterns of pneumocephalus on postoperative imaging could be predictive of CSF leaks. Identification of these patterns could guide the postoperative management of patients undergoing ESBS.

METHODS

The authors queried a prospectively acquired database of 526 consecutive ESBS cases at a single center between December 1, 2003, and May 31, 2012, and identified 258 patients with an intraoperative CSF leak documented using intrathecal fluorescein. Postoperative CT and MRI scans obtained within 1-10 days were examined and pneumocephalus was graded based on location and amount. A discrete 0-4 scale was used to classify pneumocephalus patterns based on size and morphology. Pneumocephalus was correlated with the surgical approach, histopathological diagnosis, and presence of a postoperative CSF leak.

RESULTS

The mean follow-up duration was 56.7 months. Of the 258 patients, 102 (39.5%) demonstrated pneumocephalus on postoperative imaging. The most frequent location of pneumocephalus was frontal (73 [71.5%] of 102), intraventricular (34 [33.3%]), and convexity (22 [21.6%]). Patients with craniopharyngioma (27 [87%] of 31) and meningioma (23 [68%] of 34) had the highest incidence of postoperative pneumocephalus compared with patients with pituitary adenomas (29 [20.6%] of 141) (p < 0.0001). The incidence of pneumocephalus was higher with transcribriform and transethmoidal approaches (8 of [73%] 11) than with a transsellar approach (9 of [7%] 131). There were 15 (5.8%) of 258 cases of postoperative CSF leak, of which 10 (66.7%) had pneumocephalus, compared with 92 (38%) of 243 patients without a postoperative CSF leak (OR 3.3, p = 0.027). Pneumocephalus located in the convexity, interhemispheric fissure, sellar region, parasellar region, and perimesencephalic region was significantly correlated with a postoperative CSF leak (OR 4.9, p = 0.006) and was therefore termed "suspicious" pneumocephalus. In contrast, frontal or intraventricular pneumocephalus was not correlated with postoperative CSF leak (not significant) and was defined as "benign" pneumocephalus. The amount of convexity pneumocephalus (p = 0.002), interhemispheric pneumocephalus (p = 0.005), and parasellar pneumocephalus (p = 0.007) (determined using a scale score of 0-4) was also significantly related to postoperative CSF leaks. Using a series of permutation-based multivariate analyses, the authors established that a model containing the learning curve, the transclival/transcavernous approach, and the presence of "suspicious" pneumocephalus provides the best overall prediction for postoperative CSF leaks.

CONCLUSIONS

Postoperative pneumocephalus is much more common following extended approaches than following transsellar surgery. Merely the presence of pneumocephalus, particularly in the frontal or intraventricular locations, is not necessarily associated with a postoperative CSF leak. A "suspicious" pattern of air, namely pneumocephalus in the convexity, interhemispheric fissure, sella, parasellar, or perimesencephalic locations, is significantly associated with a postoperative CSF leak. The presence and the score of "suspicious" pneumocephalus on postoperative imaging, in conjunction with the learning curve and the type of endoscopic approach, provide the best predictive model for postoperative CSF leaks.

Endoscopic extended transsphenoidal resection of tuberculum sellae meningiomas: nuances of neurosurgical technique

Over the past decade, advances in endoscopic microsurgical techniques have resulted in an increasingly aggressive endonasal approach to tumors of the midline skull base. Meningiomas of the tuberculum sellae are often closely associated with cerebrovascular structures, and their removal has traditionally required a transcranial approach. An endonasal approach offers many advantages, including early tumor devascularization and tumor debulking (without manipulation of the optic apparatus), direct access to the medial optic canal, and a minimal-access corridor.

Although recent articles have focused on techniques for reaching and approaching the area of the pathology (how to get there), the authors of this report discuss the technical nuances of endoscopic microsurgery when the operator is already “there.” They describe their 6-step technique for endoscopic skull base bone removal, tumor dissection/resection, and closure. They also augment their description with elaborate illustrations.