Neurosurgery Blog

Neurosurgery 68:788–803, 2011 DOI: 10.1227/NEU.0b013e318207ac91

Intracranial cysts containing cerebrospinal fluid (CSF) may be developmental or acquired.

OBJECTIVE: To analyze the results of endoscopic neurosurgery in the management of intracranial CSF cysts.

METHODS: In a 7-year period, 64 consecutive patients underwent endoscopic neurosurgery for CSF cysts. Group 1 consisted of 13 patients with acquired cysts; group 2 included 51 patients with developmental cysts. In all cases, the cyst walls were fenestrated through small burr holes with frameless guided operative endoscopes. Follow-up ranged from 1 to 6 years (mean, 3.4 years).

RESULTS: There were no mortality and no permanent morbidity, apart from a patient (1.6%) who remained neurologically intact but required ventriculoperitoneal shunting because of intraoperative hemorrhage. The planned fenestrations could be performed in all patients except 2, owing to thick, opaque cyst walls. In group 1, 6 patients fully recovered and remained intact throughout the follow-up, whereas 7 improved but had various degrees of neurological disabilities that were related to their initial diseases. Radiological results were excellent in all cases. In group 2, there were 7 asymptomatic patients who remained unchanged and 44 ‘‘symptomatic’’ patients: 40 (91%) clinically improved, 4 (9%) remained unchanged, and none worsened. Cyst size decreased in 37 patients (74%) and remained unchanged in 13 (26%).

CONCLUSION: In this series, patients of different ages, harboring cysts of various sizes and locations, could be satisfactorily treated with endoscopic neurosurgery.

Acta Neurochir (2011) 153:517–526.DOI 10.1007/s00701-010-0933-x

Endoscopic and stereotactic surgery have gained widespread acceptance as minimally invasive tools for the diagnosis of intracerebral pathologies. We investigated the specific advantages and disadvantages of each technique in the assessment of periventricular lesions.

Method This study included a retrospective series of 70 patients with periventricular lesions. Endoscopic surgery was performed in 17 patients (mean age, 37 years; range, 4 months–78 years) and stereotactic biopsy in 55 patients (mean age, 63 years; range, 23–80 years), including two patients who underwent both procedures.

Results Hydrocephalus was present in 13/17 patients in the endoscopic group (77%) and in 11/55 patients in the stereotactic group (20%). Diagnosis was achieved in all patients in the endoscopic group and in all but one patient in the stereotactic group, in whom histological diagnosis was obtained by endoscopic biopsy during a second operation. In the endoscopic group, additional procedures performed included ventriculostomy (2/17), cyst fenestration (3/17), endoscopic shunt revision (3/17) and placement of Rickham reservoirs or external cerebrospinal fluid drains (6/17). Adverse events occurred in one patient after endoscopy (chronic subdural hematoma) and in two patients after stereotactic surgery (one mild hemiparesis and one transitory paresis of the contralateral leg).

Conclusions Endoscopic and stereotactic surgery have distinct advantages and disadvantages in approaching periventricular lesions. The advantages of endoscopy encompass the possibility to perform additional surgical procedures during the same session (e.g. tumour reduction, third ventriculostomy, fenestration of a cyst). The visual control reduces the hazard of injury to anatomical structures and allows for a better control of bleeding although there is a considerable blind-out in such situations. The advantages of stereotactic surgery include a smaller approach and precise planning of the trajectory. It is usually performed under local anaesthesia. Both methods provide a safe and efficient therapeutic option in periventricular lesions with low surgical-related morbidity.

Childs Nerv Syst.DOI 10.1007/s00381-011-1399-8

Endoscopic cystocisternotomy is one of three surgical methods used to treat middle cranial fossa arachnoid cysts. There is debate about which method is the best.

Objective The aim of this study is to evaluate the effectiveness and safety of endoscopic cystocisternotomy for treatment of arachnoid cysts of the middle cranial fossa.

Methods Thirty-two patients with arachnoid cysts of the middle cranial fossa who had undergone endoscopic cystocisternal fenestration between 2004 and 2009 were studied retrospectively. Data were obtained on clinical and neuroradiological presentation, indications to treat, surgical technique, complications, and the results of clinical and neuroradiological follow-up.

Results Among the 27 patients with symptoms before surgery, 8 had disappearance of symptoms and 17 had improvement of symptoms. The cyst was reduced in size or it completely disappeared in 24 (75%) patients. The incidence rate of complications was 18.8%.

Conclusions Endoscopic cystocisternal fenestration is an effective treatment for symptomatic arachnoid cysts of the middle cranial fossa and should be the initial surgical procedure.

Acta Neurochir (2011) 153:1–9. DOI 10.1007/s00701-010-0788-1

Removal of tuberculum sella (TS) meningiomas is traditionally performed through transcranial approaches. Wide use of the endoscope in transphenoidal pituitary surgery is recently accessible through the tuberculum sellae with an endoscope-assisted or purely endoscopic technique. Extended endoscopic approach is an important and alternative route for meningiomas, which are located on the midline originating from the tuberculum sella. However, cerebrospinal fluid (CSF) leakage is an important problem in extended endoscopic approaches. In this report, we discuss surgical limitations and nuances of endoscopic transphenoidal approach from a retrospective analysis of nine patients with TS meningiomas.

Methods: Endoscopic transphenoidal approach was performed for seven women and two men (mean age, 51.1 years; age range, 32–78 years) with TS meningiomas between July 2007 and March 2010 in the Department of Neurosurgery, Kocaeli, Turkey.

Results: Total removal was achieved in six of nine patients. An improvement of the preoperative visual deficits was observed in six of the nine patients. Multilayer closure was performed for reconstruction, and lumbar external drainage was used for all patients for 3–5 days. CSF leakage was not seen in any of the patients after the operation and removal of the drainage.

Conclusion: Endoscopic extended transphenoidal approach is still not a standardized procedure for TS meningiomas, but it may be considered as an alternative procedure in selected cases.

Neurosurgery 68:179–187, 2011 DOI: 10.1227/NEU.0b013e3181ffae71

The endoscopic removal of third ventricular colloid cysts has been developed as an alternative to microsurgical transcortical-transventricular and transcallosal approaches.

OBJECTIVE: To examine the value of endoscopic technique by reviewing the large number of endoscopically treated patients with long-term follow-up in 2 neurosurgical centers.

METHODS: A retrospective chart review was conducted for all patients admitted for resection of a third ventricular colloid cyst to the Radboud University Nijmegen Medical Centre (Nijmegen, the Netherlands) and the Hoˆ pital Henri Mondor (Paris, France) between 1994 and 2007. Both clinical and radiological symptoms and operative results were evaluated.

RESULTS: Postdischarge clinical follow-up was available for 85 patients over a mean period of 4 years 3 months. Permanent morbidity occurred in 1 patient (persisting preoperative memory deficit). Follow-up imaging of 80 evaluable patients showed that total or nearly total cyst removal was possible in 46 individuals (57.5%). Residual cyst was present in 34 patients (42.5%), and 6 required repeated endoscopic surgery for symptomatic regrowth. Recurrent cysts were mainly seen within the first 2 years after surgery.

CONCLUSION: It is debatable whether the higher numbers of recurrent or residual cysts can be justified by the slightly lower complication rates achieved with endoscopic removal. However, results have been improving over the years. Moreover, the modifications observed on control magnetic resonance images justify the need for regular control imaging for at least the first 2 years postoperatively.

Childs Nerv Syst. DOI 10.1007/s00381-010-1339-z

As the number of endoscopic third ventriculostomy (E3V) operations increase, new rare complications are encountered. In this article, a complication caused by bone particles that migrated into the third ventricle will be described. Additionally, the methods of avoidance as well as the necessity of a new approach will be discussed.

Methods After the video images of the first and second operations of a patient who was subjected to E3V twice were compared, it was discovered that one of the bone particles within the ventricle had occluded the ostium after the second operation. Most of the bones were removed and their pathological investigations were performed.

Results Video images of the patient, surgical observations of the second operation, emergence of the time of dysfunction, and other similar cases in the literature were assessed, and it was concluded that the bones that localized intraventricularly were living tissues.

Discussion Abandoning usage of bone dust for sealing burr holes is a solution to avoid this complication. In addition, it should be kept in mind that intraventricular bone particles might grow and lead to obstructions. If such particles are detected, removal of the bones in certain locations before formation of neovascularization can be an option.

J Neurosurg Pediatrics 6:000–000, 2010. (DOI: 10.3171/2010.9.PEDS10267)

Surgery for medically intractable epilepsy secondary to unihemispheric pathology has evolved from more aggressive hemispherectomy to less aggressive variations of hemispherotomy. The authors propose a novel minimally invasive endoscopic hemispherotomy that should give results comparable to conventional open craniotomy and microsurgery.

Methods. Endoscopic transventricular hemispherotomy was performed in 5 silicon-injected cadaveric heads in the authors’ minimally invasive neurosurgery laboratory. The lateral ventricle was accessed endoscopically through a frontal and occipital bur hole. White matter disconnections were performed to unroof the temporal horn and to disconnect the frontobasal region, corpus callosum, and fornix.

Results. Using an endoscopic transventricular approach, all white matter disconnections were successfully performed in all 5 cadavers.

Conclusions. The authors have demonstrated the feasibility of endoscopic transventricular hemispherotomy in a cadaveric model. The technique is simple and could be useful in a subgroup of patients with parenchymal volume loss and ventriculomegaly.

Neurosurgery 67[ONS Suppl 2]:ons321–ons324, 2010 DOI: 10.1227/NEU.0b013e3181f74548.

Neuroendoscopy is increasingly used as an adjunctive tool in intracranial aneurysm surgery.

OBJECTIVE: To assess the versatility of a prototype continuously variable-view rigid endoscope in visualizing the anterior cerebral artery complex.

METHODS: In 5 formaldehyde-fixed, arterially injected specimens, a standard frontolateral approach was used on both sides. After meticulous microsurgical dissection using this approach, the prototype of a multivariable rigid endoscope (EndoCAMeleon; Karl Storz GmbH & Co, Tuttlingen, Germany) was inserted. It is a rigid endoscope that is capable of changing its angle of view while remaining stationary and shape invariant. We inspected the anterior cerebral artery complex, using and testing the capabilities of the device.

RESULTS: The continuously variable viewing mechanism enables the surgeon to adjust the field of view continuously and to optimize the visualization of the neurovascular structures. Because of the rigid tip combined with the continuously variable viewing mechanism, the need to move the endoscope within the surgical field was minimal. The field of view changes, but the tip itself hardly moves. The EndoCAMeleon was able to enhance both the visibility of the anterior cerebral artery complex and the accessibility of the A1 and A2 arterial walls to a range of approximately 270 degrees.

CONCLUSION: The EndoCAMeleon enhances the visibility of the anterior cerebral artery complex and facilitates endoscope-assisted inspection, planning of clip application, and clip control.

J Neurosurg 113:1100–1105, 2010. (DOI: 10.3171/2010.3.JNS09453)

Endoscopic endonasal transsphenoidal surgery (ETSS) is an effective, minimally invasive approach for the resection of anterior skull base tumors. Cerebrospinal leakage is a common complication, and repair of the anterior skull base defect with alloplastic materials has been used to minimize the risk of postoperative CSF rhinorrhea and meningitis. Injectable cements, such as low-viscosity polymethylmethacrylate (PMMA), are useful for cranial base reconstruction because they are easy to shape to the contour of the defect. These low-viscosity materials, however, are more susceptible to leakage into the nasal cavity prohibiting their use and are prone to cracking upon hardening. Cement extravasation not only obstructs the operator’s view during placement, but it is also associated with significant local and systemic complications. High-viscosity (HV) PMMA–based cement and its specialized delivery system have recently been shown to be safe and effective in human applications. Moreover, its constant high viscosity significantly reduces cement leakage and its associated complications.

The authors hypothesized that this type of cement would therefore be ideal for ETSS to repair anterior skull base defects. The authors report their experience using HV-PMMA to reconstruct the anterior skull base in 12 patients following ETSS. The unique puttylike consistency of this material is easy to work, malleable, does not leak into the nasal cavity, does not aspirate into suction tubing, and hardens without cracks in less than 10 minutes. None of the 12 patients suffered postoperative CSF leaks or infections more than 8 months, on average, after surgery.

Although not necessary in all cases of ETSS, the authors conclude that HV-PMMA, if needed, may be an excellent choice for reconstructing the anterior skull base after ETSS. Further studies are needed to better assess the long-term outcomes of HV-PMMA cement and its use in repairing skull base defects after extended ETSS.

J Neurosurg 113:967–974, 2010. DOI: 10.3171/2009.10.JNS09157

In this paper the authors’ goal was to present their clinical experience with lesions of the pterygopalatine fossa, infratemporal fossa, lateral sphenoid sinus, cavernous sinus, petrous apex, and Meckel cave using simple and extended endoscopic transpterygoid approaches to the lateral skull base.

Methods. Simple and expanded endoscopic transpterygoid approaches were performed in a series of 13 patients with varying pathology that included lateral sphenoid sinus encephaloceles, benign and malignant sinonasal tumors, and lesions of neural origin.

Results. A gross-total resection was achieved in 5 of 9 patients, while a subtotal resection for tissue diagnosis and cytoreduction prior to further adjuvant treatment was performed in the remaining patients. Sphenoid sinus encephaloceles were successfully repaired via a transpterygoid approach in all 4 patients. The skull base defect was reconstructed using a multilayered closure. One patient developed a postoperative CSF leak, which was successfully treated conservatively. The mean follow-up time was 16 months. Five patients complained of recurrent sinusitis. One patient experienced xerophthalmia and palate numbness. Three patients had died by the time of this report. Two patients died of unrelated causes. The third patient died of progression of an aggressive pterygopalatine osteosarcoma despite undergoing cytoreductive surgery and adjuvant chemotherapy.

Conclusions. An endoscopic transpterygoid approach is a minimally invasive endoscopic approach for lesions located or extending to the pterygopalatine fossa, infratemporal fossa, petrous apex, Meckel cave, and other regions of the paramedian skull base.

J Neurosurg Pediatrics 6:000–000, 2010. DOI: 10.3171/2010.8.PEDS08491

In this paper, the authors’ goal was to evaluate the role of neuroendoscopy in the treatment of arachnoid cysts of the quadrigeminal cistern.

Methods. Between March 1995 and February 2008, 14 patients affected by arachnoid cysts of the quadrigeminal cistern were treated endoscopically. The cysts were classified according to their anatomical and radiological appearance. The most frequent form (Type I) extended infratentorially and supratentorially with a dumbbell shape. Type II cysts were confined to the infratentorial space and were associated with the most severe and acute form of hydrocephalus. Type III cysts presented a significant asymmetric expansion toward the temporal fossa. Ten patients underwent an endoscopic procedure as primary treatment and 4 as an alternative to shunt revision. In 6 cases, the first endoscopic procedure was ventriculocystostomy (VC) together with endoscopic third ventriculostomy (ETV). In the other 8 cases, the first endoscopic procedure was VC alone.

Results. In the 6 cases in which VC was performed with an ETV, the procedure was successful, and the patients did not require further surgery. Of the 8 cases in which the first endoscopic procedure performed was VC without ETV, 7 underwent reoperation. Four of these patients underwent endoscopic procedures (by reopening the obstructed VC and performing ETV or cystocisternostomy) 2, 4, 4, and 5 months later with final success in all cases. Three patients (all of whom were previously treated using ventriculo- or cystoperitoneal shunts) required shunt reimplantation (complete failure). Subdural collection developed in 1 case, which was managed by transient insertion of a subduroperitoneal shunt. Neurological and developmental outcomes were good except for 1 patient who did not show improvement in preoperative developmental delay. No transient or permanent morbidity or mortality was observed.

Conclusions. The analysis of this series suggests that arachnoid cysts of the quadrigeminal cistern and the associated hydrocephalus can be effectively treated by endoscopy; this approach allows the patient to be shunt independent in more than 78% of the cases. If endoscopy is used as first option, the success rate of endoscopic procedures observed in this series was 90%. Endoscopic third ventriculostomy should be associated with a VC to offer the highest success rate with a single procedure.

Neurosurg Focus 29 (4):E5, 2010. DOI: 10.3171/2010.7.FOCUS10153

Using strict biochemical remission criteria, the authors assessed surgical outcomes after endoscopic transsphenoidal resection of growth hormone (GH)–secreting pituitary adenomas and identified preoperative factors that significantly influence the rate of remission.

Methods. A retrospective review of a prospectively maintained database was performed. The authors reviewed cases in which an endoscopic resection of GH-secreting pituitary adenomas was performed. The cohort consisted of 26 patients who had been followed for 3–60 months (mean 24.5 months). The thresholds of an age-appropriate, normalized insulin-like growth factor–I concentration, a nadir GH level after oral glucose load of less than 1.0 μg/l, and a random GH value of less than 2.5 μg/l were required to establish biochemical cure postoperatively.

Results. Overall, in 57.7% of patients undergoing a purely endoscopic transsphenoidal pituitary adenectomy for acromegaly, an endocrinological cure was achieved. The mean clinical follow-up duration was 24.5 months. In patients with microadenomas (4 cases) the cure rate was 75%, whereas in patients harboring macroadenomas (22 cases) the cure rate was 54.5%. Cavernous sinus invasion (Knosp Grades 3 and 4) was associated with a significantly lower remission rate (p = 0.0068). Hardy Grade 3 and 4 tumors were also less likely to achieve biochemical cure (p = 0.013). The overall complication rate was 11.5% including 2 incidents of transient diabetes insipidus and 1 postoperative CSF leak, which were treated nonoperatively.

Conclusions. A purely endoscopic transsphenoidal approach to GH-secreting pituitary adenomas leads to similar outcome for noninvasive macroadenomas compared with traditional microsurgical techniques. Furthermore, this approach may often provide maximal visualization of the tumor, the pituitary gland, and the surrounding neurovascular structures.

Neurosurgery 67:824-836, 2010 DOI: 10.1227/01.NEU.0000377852.75544.E4

Surgical treatment of arachnoid cysts remains under debate. Although many authors favor endoscopic techniques, others attribute a higher recurrence rate to the endoscope.

OBJECTIVE: The authors report their experience with endoscopic procedures for arachnoid cyst.

METHODS: All pure endoscopic procedures for arachnoid cysts performed by the authors were analyzed. Particular reference was given to surgical complications and patient outcome in relation to cyst location and endoscopic technique.

RESULTS: Sixty-six endoscopic procedures were performed in 61 patients (mean age, 28 years; range, 23 days to 74 years; 35 males, 26 females). The main presenting symptoms were cephalgia (61%), hemisymptoms (18%), and macrocephalus (18%). Cyst location was temporobasal (34%), suprasellar (21%), at the cisterna quadrigemina (18%), paraxial supratentorial (16%), and various (10%). Thirty cystocisternostomies, 14 ventriculocystostomies, 12 cystoventriculostomies, and 10 ventriculocystocisternostomies were performed. The overall clinical success rate was 90%. The endoscopic technique was abandoned in 4 cases (7%). Postoperative complications were found in 16%; there was only one permanent deficit (2%). Five recurrences (8%) occurred up to 7 years after the first procedure. Of the various locations, the temporobasal cysts were the most difficult to treat with lowest clinical success (81%), highest recurrence (19%), and highest complication rate (24%). Of the various endoscopic techniques, ventriculocystostomy and ventriculocystocisternostomy reached the highest success rates with 100%.

CONCLUSIONS: Endoscopic techniques provide very good results in arachnoid cyst treatment. The most frequent cyst location is the most difficult to treat. A long-term follow-up is recommended since recurrences can occur many years after the procedure

Neurosurgery 67:588-593, 2010 DOI: 10.1227/01.NEU.0000373199.79462.21

Endoscopic third ventriculostomy (ETV) has preferentially been offered to patients with more favorable prognostic features compared with shunt.

OBJECTIVE: To use advanced statistical methods to adjust for treatment selection bias to determine whether ETV survival is superior to shunt survival once the bias of patientrelated prognostic factors is removed.

METHODS: An international cohort of children (≤ 19 years of age) with newly diagnosed hydrocephalus treated with ETV (n = 489) or shunt (n = 720) was analyzed. We used propensity score adjustment techniques to account for 2 important patient prognostic factors: age and cause of hydrocephalus. Cox regression survival analysis was performed to compare time-to-treatment failure in an unadjusted model and 3 propensity score—adjusted models, each of which would adjust for the imbalance in prognostic factors.

RESULTS: In the unadjusted Cox model, the ETV failure rate was lower than the shunt failure rate from the immediate postoperative phase and became even more favorable with longer duration from surgery. Once patient prognostic factors were corrected for in the 3 adjusted models, however, the early failure rate for ETV was higher than that for shunt. It was only after about 3 months after surgery did the ETV failure rate become lower than the shunt failure rate.

CONCLUSIONS: The relative risk of ETV failure is initially higher than that for shunt, but after about 3 months, the relative risk becomes progressively lower for ETV. Therefore, after the early high-risk period of ETV failure, a patient could experience a long-term treatment survival advantage compared with shunt. It might take several years, however, to realize this benefit.

Neurosurgery 67[ONS Suppl 1]:ons00-ons00, 2010. DOI: 10.1227/01.NEU.0000354351.00684.B9

To describe a transnasal endoscopic route to the jugular foramen and the endoscopic anatomy of the infratemporal fossa.

CLINICAL PRESENTATION: Endoscopic transnasal dissection of the infratemporal fossa was performed in 3 injected fresh heads (1 head only in arteries and 2 heads in arteries and veins). Two other double-injected specimens were dissected externally (2 of them side laterally and 1 anteriorly) to compare the different views and better understand the 3-dimensionality of the region. Detailed endoscopic anatomy of the infratemporal fossa was clearly observed. The realization of a septal and posterior maxillary window allows surgeons to gain space to the jugular foramen. The ability to manage the vessels, especially the veins, and identify the muscles is mandatory. The fundamental role of the vidian canal in targeting the anterior genu of the internal carotid artery is confirmed. The role of the maxillary and mandibular branches of the trigeminal nerve and the eustachian tube in this kind of approach is critical.

CONCLUSION: A fully transnasal endoscopic route to the jugular foramen is feasible. The most important landmark for this kind of approach is the eustachian tube.

J Neurosurg 112:1333–1339, 2010. DOI: 10.3171/2009.10.JNS09348

Acta Neurochir (2010) 152:1015–1020. DOI 10.1007/s00701-010-0629-2

The endoscopic endonasal transsphenoidal approach (EETA) to the pituitary is performed by ear, nose, and throat (ENT) surgeons in collaboration with neurosurgeons but also by neurosurgeons alone even though neurosurgeons have not been trained in rhinological surgery.

Purpose To register the frequency of endonasal anatomical variations and to evaluate whether these variations hinder the progress of EETA and require extra rhinological surgical skills.

Methods A prospective cohort study of 185 consecutive patients receiving an EETA through a binostril approach was performed. All anatomical endonasal variations were noted and the relevance for the progress of surgery evaluated.

Results In 48% of patients, anatomical variations were recognized, the majority of which were spinae septi and septum deviations. In 5% of patients, the planned binostril approach had to be converted into a mononostril approach; whereas in 18% of patients with an anatomical variation, a correction had to be performed. There was no difference between the ENT surgeon and the neurosurgeon performing the approach. Complications related to the endonasal phase of the surgery occurred in 3.8%. Fluoroscopy or electromagnetic navigation has been used during 6.5% of the surgeries.

Conclusion Although endonasal anatomical variations are frequent, they do not pose a relevant obstacle for EETA.

Neurosurgery 66:883-892, 2010 DOI: 10.1227/01.NEU.0000368395.82329.C4

The anterior skull base, in front of the sphenoid sinus, can be approached using a variety of techniques including extended subfrontal, transfacial, and craniofacial approaches. These methods include risks of brain retraction, contusion, cerebrospinal fluid leak, meningitis, and cosmetic deformity. An alternate and more direct approach is the endonasal, transethmoidal, transcribriform, transfovea ethmoidalis approach.

METHODS: An endoscopic, endonasal approach was used to treat a variety of conditions of the anterior skull base arising in front of the sphenoid sinus and between the orbits in a series of 44 patients. A prospective database was used to detail the corridor of approach, closure technique, use of intraoperative lumbar drainage, operative time, and postoperative complications. Extent of resection was determined by a radiologist using volumetric analysis.

RESULTS: Pathology included meningo/encephaloceles (19), benign tumors (14), malignant tumors (9), and infectious lesions (2). Lumbar drains were placed intraoperatively in 20 patients. The CSF leak rate was 6.8% for the whole series and 9% for intradural cases. Leaks were effectively managed with lumbar drainage. Early reoperation for cerebrospinal fluid (CSF) leak occurred in 1 patient (2.2%). There were no intracranial infections. Greater than 98% resection was achieved in 12 of 14 benign and 5 of 9 malignant tumors.

CONCLUSION: The endoscopic, endonasal, transethmoidal, transcribriform, transfovea ethmoidalis approach is versatile and suitable for managing a variety of pathological entities. This minimal access surgery is a feasible alternative to transcranial, transfacial, or combined craniofacial approaches to the anterior skull base and anterior cranial fossa in front of the sphenoid sinus. The risk of CSF leak and infection are reasonably low and decrease with experience. Longer follow-up and larger series of patients will be required to validate the long-term efficacy of this minimally invasive approach.

J Neurosurg Pediatrics 5:02050–200540, 2010. DOI: 10.3171/2009.10.PEDS09187

Neurosurgery. 66(4):797-816, April 2010. doi: 10.1227/01.NEU.0000367619.24800.B1

The transsphenoidal approach has been extended in recent years from tumors of the sellar region to lesions involving other areas bordering the sphenoid sinus including the cavernous sinus, Meckel’s cave, middle cranial fossa, planum sphenoidal, suprasellar region, and clivus. The goal of this study was to examine various pneumatized extensions of the sphenoid sinus that may facilitate extended approaches directed through the sinus.

METHODS: The sphenoid sinus and its surrounding structures were examined in 18 cadaver heads, and the results were correlated with the findings from 100 computed tomography images of the sinus. The sellar type of the sphenoid sinus in which the pneumatization extended beyond the anterior sellar wall was further classified according to the various extensions of the sinus.

RESULTS: The sellar type of the sphenoid sinus was classified into the following 6 basic types based on the direction of pneumatization: sphenoid body, lateral, clival, lesser wing, anterior, and combined. The recesses and prominences, formed by pneumatization of the sinus, act as “windows” opening from the sinus in different areas of the cranial base and may facilitate minimally invasive access to lesions in the corresponding areas.

CONCLUSION: The variations in the extensions of pneumatization of the sphenoid sinus may facilitate entry into areas bordering the sphenoid sinus and play a role in the selection of a surgical approach to lesions bordering the sinus.