Transpterygoid Trans-sphenoid Approach to the Lateral Extension of the Sphenoid Sinus to Repair a Spontaneous CSF Leak

How I do it? Endoscopic endonasal transpterygoid repair of sphenoid lateral recess cerebrospinal fluid leak after previous unsuccessful transcranial surgery

BACKGROUND

Direct access to the sphenoid lateral recess offers the best chance of sealing spontaneous cerebrospinal fluid (CSF) rhinorrhea caused by lateral sphenoid encephaloceles of the Sternberg canal defect.

METHOD

We present a case of spontaneous left-sided sphenoid lateral recess CSF leak after previous unsuccessful transcranial surgery managed with an endoscopic endonasal transpterygoid approach (EETA). An anatomical-based step-by-step illustration of the EETA was presented in the surgical video.

CONCLUSION

This case demonstrates the value of endoscopic endonasal transpterygoid corridor in the exposure and manipulation of the sphenoid lateral recess.

[Endonasal repair of spontaneous CSF fistulas of the lateral recess of the sphenoid sinus]

CSF fistulas of the lateral recess of the sphenoid sinus are a rare surgical pathology. Cerebrospinal fluid leak from lateral recess of the sphenoid sinus is observed with a frequency of 7.7% among all leakafe of the skull base. The article presents 3 clinical cases of patients with spontaneous cerebrospinal fluid leak from lateral recess of the sphenoid sinus and surgical treatments by transsphenoidal and transpterygoid (transpterygoid) endoscopic approaches with various postoperative results. The plastic surgery success of CSF fistulas from lateral recess of the sphenoid sinus doesn`t depend on the type of endonasal surgical approach, but on the plastic quality and the preoperative level of CSF pressure.

Endonasal Exposure of Lateral Recess of the Sphenoid Sinus: Significance of Pterygoid Process Pneumatization

Background

Caudal pneumatization of the pterygoid process may impact endonasal exposure of the lateral recess of sphenoid sinus (LRSS).

Objectives

This study aims to explore the implications of a pneumatized pterygoid process for an endonasal transpterygoid approach to the LRSS and to define strategies regarding the preservation or sacrifice of the vidian nerve.

Methods

Dissection of the LRSS (11 sides) was performed on 6 cadaveric specimens, preselected for the radiographic presence of an LRSS. In addition, the dimensions of the LRSS were measured on the deidentified CT images of 120 patients (240 sides). The sphenoid sinus was subdivided into 3 categories: Type 1 (no identifiable LRSS), Type 2 (lateral pneumatization of the greater wing above the vidian canal), and Type 3 (pneumatization of both the greater wing and the pterygoid process).

Results

On the cadaveric specimens, a Type 2 pneumatization often allowed access to the LRSS above the level of the vidian canal; thus, sparing the vidian neurovascular bundle. In Type 3 pneumatization, a frontal corridor through the pterygoid base could be created to reach the LRSS with preservation of the vidian nerve. Extreme Type 3 pneumatization, however, required the transposition or sacrifice of the vidian nerve to facilitate a full direct access to the superolateral LRSS. Measurements on CT images revealed that the extent of caudal pneumatization of the pterygoid process had no statistically significant correlation with the superolateral extension of the lateral recess in patients with Type 3 LRSS ( P > .05).

Conclusion

Pneumatization of the LRSS toward a caudal or superolateral direction may develop independent from each other. Caudal pneumatization of the pterygoid process seems to variably impact the endonasal exposure of the LRSS.

Endoscopic Repair of Spontaneous Cerebrospinal Fluid Leaks in the Lateral Recess of the Sphenoid Sinus

OBJECTIVE

This study aimed to assess the effectiveness of 3 endoscopic endonasal approaches for the management of cerebrospinal fluid (CSF) leaks and meningoencephaloceles in the lateral recess of the sphenoid sinus (LRSS).

STUDY DESIGN

Retrospective study.

SETTING

University hospital.

METHODS

This study retrospectively reviewed 49 patients with CSF leaks and meningoencephaloceles in the LRSS. Three endoscopic surgical repair approaches were indicated based on 5 different Rhoton's types of the LRSS. The postoperative symptoms, complications, and follow-up outcomes were investigated and evaluated.

RESULTS

The success rate of endoscopic surgical repair was 100% at a median follow-up of 75.06 (12-203.4) months. Endoscopic approaches to the LRSS included the prelacrimal recess (PLR) (18.37%), transsphenoidal (18.37%), and transpterygoid approaches (64.26%). All patients in the PLR approach (PLRA) group and most of the patients in the transpterygoid approach group had a full lateral type LRSS. Hypoesthesia and dry eyes were reported in 5 patients (55.56%) and 1 (11.12%) patient, respectively, from the PLRA group and in 6 (19.35%) and 5 (16.12%) patients, respectively, from the transpterygoid approach group.

CONCLUSIONS

Endoscopic closure is a safe and effective method for the treatment of CSF leaks and meningoencephaloceles in the LRSS. The transpterygoid approach and PLRA offer adequate exposure of the LRSS with extensive lateral pneumatization or a full LRSS. The endoscopic route of the PLRA is more direct than that of the transpterygoid approach. Careful preoperative imaging evaluation is crucial while selecting the optimal surgical approach for the repair of a skull base defect.

Endoscopic management of lateral sphenoid cerebrospinal fluid leaks: Identifying a radiographic parameter for surgical planning

OBJECTIVE

Repair of cerebrospinal fluid (CSF) leaks of the lateral recess of the sphenoid (LRS) sinus can be challenging to accomplish via an endoscopic transphenoidal approach. The endoscopic transpterygoid approach can improve surgical access to the lateral recess but requires more extensive surgical dissection. We review our experience with LRS CSF leak repair via both techniques to determine whether preoperative radiologic data can help predict the most appropriate surgical approach.

METHODS

Electronic medical records of patients with LRS CSF leaks were retrospectively reviewed at a single tertiary referral center. Radiographic measurements from preoperative computed tomography images were reviewed.

RESULTS

Twenty-two LRS CSF leaks were identified. The transphenoidal and transpterygoid approach were used in 6 (27.3%) and 16 (72.7%) cases, respectively.The mean vidian canal to foramen rotundum angle of the repairs accessed transphenoidally as compared to the transptyergoid approach were not significantly different (41.93° ±10.91, 40.72° ±19.49, respectively; P = .63). However, the mean volume of the LRS accessed by the transpterygoid approach was significantly greater compared to those accessed through the transphenoidal approach (0.97 cm3 ± 0.48, 0.39 cm3 ± 0.40, respectively; P = .04). A LRS volume of 0.400 cm3 or greater predicted the use of the transpterygoid approach with 93.3% sensitivity and 60.0% specificity.

CONCLUSION

This study demonstrated that LRS CSF leaks that necessitated repair by the transpterygoid approach, rather than transphenoidal approach, were in the context of significantly larger lateral recess. Assessment of the LRS volume is a quantifiable parameter to aid in preoperative surgical planning.

LEVEL OF EVIDENCE

Level 4.

A Rare Case of Sphenoid Encephalocoele Presenting with Fifth Cranial Nerve Involvement

A 14-year-old girl presented with chronic headache, recurrent episodes of vomiting, fever, and two episodes of generalized tonic clonic seizure in the past 2 months. Neuroimaging revealed herniation of the brain along with the dura through a defect in the left greater wing of the sphenoid. Left pterional craniotomy was carried out. Herniation of the dural sac along with its contents through the bony defect in the greater sphenoid wing was identified lateral to the V2 nerve passing through the foramen rotundum. The dural defect was repaired. Bony defect was covered with a circular titanium plate. The patient did not have cerebrospinal fluid rhinorrhea postoperatively. At 6-month follow-up, she was asymptomatic.

Endoscopic prelacrimal approach to lateral recess of sphenoid sinus: feasibility study

BACKGROUND

Various pathologies, including cerebrospinal fluid leaks and meningoencephaloceles, may arise in the lateral recess of the sphenoid sinus (LRSS), which may be accessed via an endonasal transpterygoid approach. The objective of this study was to evaluate the feasibility of accessing the LRSS via an endoscopic prelacrimal approach. Furthermore, we hypothesized that this approach may protect the pterygopalatine ganglion and vidian nerve.

METHODS

Five cadaveric heads (9 sides) with a well-pneumatized LRSS were identified and an endonasal prelacrimal approach was performed. The infraorbital nerve, at the orbital floor, served as a critical landmark. After identification of the foramen rotundum at the pterygoid base, the vascular compartment of the pterygopalatine fossa and the pterygopalatine ganglion were displaced inferomedially and superomedially, respectively. Drilling of the bone inferomedial to the foramen rotundum allowed entry into the LRSS.

RESULTS

The average distances from the prelacrimal window to the pterygoid base and the posterior wall of the LRSS were 6.22 ± 0.39 cm and 7.16 ± 0.50 cm, respectively. The average areas of the bony prelacrimal window and pterygoid base window were 4.33 ± 0.32 cm² and 0.73 ± 0.10 cm² , respectively. The LRSS could be accessed using a 0-degree endoscope, and pterygopalatine neurovascular structures, including the pterygopalatine ganglion and vidian nerve, could be preserved on all 9 sides.

CONCLUSION

Our findings suggest that an endonasal prelacrimal approach provides a reasonable alternative to access the LRSS while preserving the vidian nerve and pterygopalatine ganglion.

Cranial nerve V2 and Vidian nerve trauma secondary to lateral pterygoid recess encephalocele repair

BACKGROUND

The incidence of adverse sequelae related to trauma of cranial nerve V₂ (V2) and the Vidian nerve (VN) during endoscopic pterygoid recess repair (PRR) of lateral sphenoid encephalocele is insufficiently reported in the medical literature. As part of our quality assessment and improvement program we sought to analyze the incidence and severity of V2 and VN injury during a 9-year experience (2010-2018) with PRR.

METHODS

Hypoesthesia, paresthesia, and dry eye and their impact on patient quality of life were sought through chart review and a self-reported 0 to 5 Likert scale for each symptom.

RESULTS

Thirty-five patients underwent repair of spontaneous cerebrospinal-fluid (CSF) rhinorrhea, with 11 consecutive patients undergoing endoscopic PRR. Mean follow-up for PRR was 32.5 months (range, 2.4 to 103.3 months). Although definitive management resulted in 100% success, 1 required secondary treatment. Eight patients were available for long-term follow-up (72.7%) and completed a symptom severity questionnaire using a Likert-scale. All patients observed either hypoesthesia, paresthesia, or dry eye of varying gradation (scale, 0 to 5). None described disabling symptoms, and some reported gradual improvement. Numbness, paresthesia, and dry eye were reported by 6 of 8 (75%), 5 of 8 (62.5%), and 4 of 8 (50%) patients, respectively. The mean Likert score among the 8 patients who completed this questionnaire noticing hypoesthesia, paresthesia, and dry eye was 2.6, 1.3, and 1.8, respectively.

CONCLUSION

Meticulous surgical technique is paramount for successful PRR and minimizing nerve injury, yet the anatomic variation of the lateral pterygoid recess can be challenging, and neural injury is a real risk. Preoperatively, patients should be counseled that although V2 or VN injury is common, most patients describe resulting symptoms to be rarely bothersome.

Endoscopic Endonasal Transpterygoid Approach to Sphenoid Sinus Lateral Recess Defects

Background  Lesions affecting sphenoid sinus lateral recess (SSLR) are difficult to visualize and manipulate through the transnasal routes, especially when the sinus is highly pneumatized. External approaches to this area involve extensive surgery and are associated with significant morbidity. The aims of this study are to present our experience with the endoscopic transpterygoid approach as a method for approaching lesions of the SSLR and to evaluate the outcomes of this procedure. Methods  Clinical charts of patients who had lesions in the SSLR and who were treated at our institution from September 1998 to June 2018 were retrospectively reviewed. All these patients were managed by the endoscopic endonasal transpterygoid approach. Results  Thirty-nine patients were identified. No cerebrospinal fluid leak recurrences were observed during follow-up (range: 1-19.7 years; median: 2.3 years). Hypoesthesia (temporary, 1; persistent, 4) in the region innervated by the maxillary branch of the trigeminal nerve was detected in five (12.8%) patients, while symptoms due to the Vidian nerve damage (dry eye, 3; dry nasal mucosa, 1) were present in four (10%) patients. Conclusions  Although the endoscopic endonasal transpterygoid approach is an excellent corridor for dealing with lesions of the SSLR, limited rate of neurologic and lacrimal complications was observed. Potential morbidity of the intervention should be discussed during preoperative counselling.

Spontaneous CSF rhinorrhea from the trigeminal canal in an adolescent

We report a case of a seventeen-year old, healthy, non-obese young woman who presented with retro-orbital headaches and metallictasting, left-sided rhinorrhea. Computed tomography revealed a defect along the medial wall of the canal of V2 within a well-pneumatized lateral recess of the left sphenoid sinus. Prior imaging obtained 4 years earlier in the context of nasal trauma showed no such defect - thus lending support for the arachnoid granulation hypothesis of spontaneous CSF leaks from the sphenoid sinus. We perform a literature review and describe a successful repair through an endoscopic transpterygoid approach, which allowed for resolution of symptoms with minimal postoperative morbidity.

A Case of Evolving Bilateral Sphenoidal Meningoencephaloceles: Case Report and Review of the Literature

BACKGROUND

The evolution of sphenoid sinus meningoencephaloceles and cerebrospinal fluid (CSF) rhinorrhea is poorly understood.

CASE DESCRIPTION

We present a case demonstrating the gradual evolution of encephaloceles from both the lateral walls of a previously normal sphenoid sinus in a patient with dural arteriovenous fistula; the CSF leak that developed after staged embolization of the dural arteriovenous fistula was managed by an endoscopic endonasal transpterygoid approach.

CONCLUSIONS

We suggest that over a period of time, chronic elevation of intracranial pressure can result in gradual erosion of the lateral wall of the sphenoid with development of meningoencephaloceles and CSF leaks.

The Pedicled Buccal Fat Pad: Anatomical Study of the New Flap for Skull Base Defect Reconstruction After Endoscopic Endonasal Transpterygoid Surgery

Objectives To evaluate the efficacy and safety of using a buccal fat pad for endoscopic skull base defect reconstruction. Design Descriptive anatomical study with an illustrative case presentation. Setting Anatomical study was performed on 12 fresh human cadaver specimens with injected arteries (24 sides). Internal carotid artery was exposed in the coronal plane via the endoscopic transpterygoid approach. The pedicled buccal fat pad was used for reconstruction. Participants: 12 human cadaver head specimens; one patient operated using the proposed technique. Main outcome measures: Proximity of the buccal fat pad flap to the defect, compliance of the flap, comfort and safety of harvesting procedure, and compatibility with the Hadad-Bassagasteguy nasoseptal flap. Results: Harvesting procedure was performed using anterior transmaxillary corridor. The pedicled buccal fat pad flap can be used to pack the sphenoid sinus or cover the internal carotid artery from cavernous to upper parapharyngeal segment. Conclusion The buccal fat pad can be safely harvested through the same approach without external incisions and is compliant enough to conform to the skull base defect. The proposed pedicled flap can replace free abdominal fat in central skull base reconstruction. The volume of the buccal fat pad allows obliteration of the sphenoid sinus or upper parapharyngeal space.

A modification of endoscopic endonasal approach for management of encephaloceles in sphenoid sinus lateral recess

Spontaneous cerebrospinal fluid leak with meningoencephaloceles in sphenoid sinus lateral recess is challenging. Transnasal visualization of this area is difficult, especially when large pneumatization is present. External approaches to this region involve aggressive surgery and are often associated with significant morbidity. The aim of this study is to assess the real effectiveness of a modification of the endoscopic endonasal approach for their management. This is a prospective case series study and was conducted at Otolaryngology department, Ain Shams University Hospitals, Cairo, Egypt. Seven patients with spontaneous cerebrospinal fluid leak with meningoencephaloceles in the sphenoid sinus lateral recess were included. Diagnosis was confirmed by: analysis for beta-2 transferrin and imaging. They were managed with endoscopic endonasal retrograde trans-sphenoid approach described in this study with multilayered reconstruction of the defect. Mean age of our patients was 40.14 ± 8.35 years; mean BMI was 36.37 ± 2.59 kg/m². Primary empty sella was present and osteodural defect was identified in superior wall of sphenoid sinus lateral recess with punched out and regular smooth edges. Mean intra-cranial pressure was (26.42 ± 3.87 mmH₂O) and size of defect was less than 10 mm, mean 7.85 ± 1.34. Mean-operative time was 169.28 ± 21.87 min. The mean hospital stay was 7.42 ± 1.39 days. No cerebrospinal fluid leak recurrences were observed during follow-up period that ranged from 37 to 48 months. Endoscopic endonasal retrograde trans-sphenoid approach provides a wide, safe, and direct route to the management of sphenoid sinus lateral recess cerebrospinal fluid leak.

Comprehensive review on endonasal endoscopic sinus surgery

Endonasal endoscopic sinus surgery is the standard procedure for surgery of most paranasal sinus diseases. Appropriate frame conditions provided, the respective procedures are safe and successful. These prerequisites encompass appropriate technical equipment, anatomical oriented surgical technique, proper patient selection, and individually adapted extent of surgery. The range of endonasal sinus operations has dramatically increased during the last 20 years and reaches from partial uncinectomy to pansinus surgery with extended surgery of the frontal (Draf type III), maxillary (grade 3-4, medial maxillectomy, prelacrimal approach) and sphenoid sinus. In addition there are operations outside and beyond the paranasal sinuses. The development of surgical technique is still constantly evolving. This article gives a comprehensive review on the most recent state of the art in endoscopic sinus surgery according to the literature with the following aspects: principles and fundamentals, surgical techniques, indications, outcome, postoperative care, nasal packing and stents, technical equipment.

Transorbital neuroendoscopic surgery for the treatment of skull base lesions

Transorbital neuroendoscopic surgery (TONES) is a relatively new technique that not only allows access to the contents of the orbit but also the intracranial compartment, including the anterior cranial fossa, middle fossa and lateral cavernous sinus. In this study, we aimed to retrospectively review the largest experience to our knowledge with regards to surgical outcomes of skull base pathologies treated with a TONES procedure. Forty patients (aged 3-89 years) underwent 45 TONES procedures between the years of 2006-2013. Pathologies were cerebrospinal fluid leak repair (n=16), traumatic fracture (n=8), tumor (n=11), meningoencephalocele (n=5), hematoma (n=1), and infection (n=4). Three patients had a persistent complication at 3 months, including a case each of enophthalmos (unnoticed by patient), epiphora (delayed presentation at 2 months requiring dacryocystorhinostomy), and ptosis (improved at 1 year). Surgical success was achieved in all patients. Of special import, there were no cases of visual decline, diplopia, or stroke. There was no mortality. To our knowledge this is the first study and largest experience of TONES (level 4 evidence) to detail outcomes with respect to skull base pathologies. Our results indicate that TONES procedures can be performed with minimal morbidity. Further studies are needed to assess equivalency with craniotomy based approaches though this initial report is encouraging.

Endoscopic transpterygoid approach and skull base repair after sphenoid meningoencephalocele resection. Our experience

INTRODUCTION AND OBJECTIVES

Cerebrospinal fluid leaks associated to meningoencephaloceles of the sphenoid lateral recess are rare entities. A congenital bony defect at this level results in the persistence of Sternberg's canal, or a lateral craniopharyngeal canal, which is supposed to be the origin of these lesions. Our objective was to show that the endoscopic transpterygoid approach is an effective technique for their treatment.

METHODS

We present a series of 5 cases of meningoencephaloceles of the sphenoid lateral recess treated with endoscopic sinus surgery (4 women and one man; mean age=59, range 37-72 years). Cerebrospinal fluid rhinorrhoea was present in all of them and they all underwent a transpterygoid approach with reconstruction of the skull base. We describe the surgical technique and review the literature.

RESULTS

No complications were observed during surgery or the postoperative period. After a mean follow-up of 81 months, only one recurrence was seen.

CONCLUSIONS

The transpterygoid approach has proven to be effective for the treatment of meningoencephaloceles of the sphenoid lateral recess. Providing wide access to identify the defect, followed by meningoencephalocele ablation, is the key for successful surgery.

Spontaneous sphenoid wing meningoencephaloceles with lateral sphenoid sinus extension: the endoscopic transpterygoid approach

Spontaneous meningoencephalocele (SME) of the sphenoid wing is a rare cause of cerebrospinal fluid (CSF) leakage. Surgical closure of the fistula is usually required. The approach taken depends on the location of the defect and the extension of the meningoencephalocele. The endoscopic transpterygoid approach may be useful. We prospectively analyzed the three cases of SME of the sphenoid wing with lateral sphenoid sinus extension treated endoscopically at Stanford over the last 3 years with regard to imaging findings, operative technique, and operative morbidity. In our three cases, the extent of pterygopalatine fossa (PPF) exposure undertaken, complete in one and partial in two, depended on the defect site. Follow-up ranged from 17 to 25 months. The fistula was completely closed in all three cases. Extant literature reports a 97% rate of successful closure (N = 65 of 67, with a mean follow-up of 25 months) and no major complications. Endoscopic transpterygoid repair is a useful, safe alternative to traditional approaches for repair of SME of the sphenoid wing. Its feasibility depends on the site of the defect, which can be identified by preoperative imaging. Larger PPF exposure and postoperative lumbar drainage of CSF can be useful and have a low risk of morbidity.

Surgical nuances for the endoscopic endonasal transpterygoid approach to lateral sphenoid sinus encephaloceles

Lateral sphenoid encephaloceles of the Sternberg canal are rare entities and usually present with spontaneous CSF rhinorrhea. Traditionally, these were treated via transcranial approaches, which can be challenging given the deep location of these lesions. However, with advancements in endoscopic skull base surgery, including improved surgical exposures, angled endoscopes and instruments, and novel repair techniques, these encephaloceles can be resected and successfully repaired with purely endoscopic endonasal approaches. In this report, the authors review the endoscopic endonasal transpterygoid approach to the lateral recess of the sphenoid sinus for repair of temporal lobe encephaloceles, including an overview of the surgical anatomy from an endoscopic perspective, and describe the technical operative nuances and surgical pearls for these cases. The authors also present 4 new cases of lateral sphenoid recess encephaloceles that were successfully treated using this approach.

Endoscopic repair of anterior or middle skull base cerebrospinal fluid leaks after tumour resection

OBJECTIVES

This study analysed the factors influencing the risk of recurrence following endoscopic repair of CSF leaks of the anterior and middle skull base after endonasal skull base tumour resection.

PATIENTS AND METHODS

A retrospective review was conducted on 17 patients operated between May 2007 and December 2010 by endonasal endoscopic resection of anterior or middle skull base tumour who presented an intraoperative CSF leak. Epidemiological data (body mass index [BMI], age, gender) and type of leak (site, size) were studied.

RESULTS

CSF leaks involved the roof of the ethmoid sinus (one patient), cribriform plate (three), posterolateral wall of the sphenoid sinus (six) or the sella turcica (seven). The CSF leak recurrence rate after the first endoscopic procedure was 29.4% (5/17). Failures were not influenced by gender, age, BMI or size of the leak. All recurrences involved the sella turcica or the lateral wall of the sphenoid sinus. The success rate after a second endoscopic procedure was 88.2%.

CONCLUSION

Endonasal endoscopic repair of anterior and middle skull base meningeal injuries after tumour resection is a minimally invasive and effective technique. The main challenge of this method consists of ensuring effective control of the postoperative defect after tumour resection in the sphenoidal region, as this region was the only potential risk factor for recurrence identified in this study.

Sternberg's canal as a cause of encephalocele within the lateral recess of the sphenoid sinus: A report of two cases

Background:

Intrasphenoidal encephaloceles are extremely rare findings. Sternberg's canal is a lateral craniopharyngeal canal resulting from incomplete fusion of the greater wings of the sphenoid bone with the basisphenoid. It acts as a weak spot of the skull base, which may lead to develop a temporal lobe encephalocele protruding into the lateral recess of the sphenoid sinus (SS).

Case Description:

We present two cases of intrasphenoidal encephalocele due to persistence of the lateral craniopharyngeal canal. The first case presented with cerebrospinal fluid (CSF) rhinorrhea and the second one was referred to the neurosurgical department with CSF rhinorrhea and meningitis. Radiological investigations consisted of computed tomography (CT) scan, CT cisternography and magnetic resonance images in both cases. These imaging studies identified a herniated temporal lobe through a bony defect which communicates the middle cranial fossa with the lateral recess of the SS. Both patients underwent a transcranial repair of the encephalocele because of the previous failure of the endoscopic surgery. There was no complication related to the surgical procedure and no recurrence of CSF leakage occurred 2 and 3 years after surgery, respectively.

Conclusion:

Encephalocele within the lateral recess of the SS is a rare entity which must be suspected in patients who present with spontaneous CSF rhinorrhea. Congenital intrasphenoidal encephaloceles, which are located medial to the foramen rotundum, seem to be due to persistence of the Sternberg's canal. Transcranial approach is a good option when a transnasal approach had failed previously.

Temporal lobe encephalocele in the lateral recess of the sphenoid sinus presenting with intraventricular tension pneumocephalus

A basal encephalocele often shows an insidious clinical course. Only two cases of temporal lobe encephalocele accompanied with tension pneumocephalus have previously been reported. In this paper, we describe a case of lateral sphenoid sinus encephalocele presenting with intraventricular tension pneumocephalus. A 54-year-old man was referred to our institution presenting with intraventricular tension pneumocephalus. He had undergone ventriculoperitoneal shunt placement for postmeningitis hydrocephalus 3 months before this admission. Precise imaging examinations detected evidence suggestive of a lateral sphenoidal sinus recess encephalocele. Endoscopic transnasal approach was performed for surgical repair of the encephalocele. The encephalocele was removed with subsequent repair of the bony defect. Histological examination showed that the encephalocele includes a part of the ventricular system. This indicates that air might enter directly into the ventricular system after rupture of the temporal lobe encephalocele. A lateral sphenoid sinus encephalocele would potentially cause intraventricular tension pneumocephalus, although pneumocephalus is an extremely unusual complication of this type of basal encephaloceles.

Spontaneous cerebrospinal fluid rhinorrhea associated with a far lateral temporal encephalocele--case report

A 35-year-old female complained of right-sided watery nasal discharge persisting for 2 weeks. Neuroimaging investigations revealed a defect in the lateral side of middle cranial fossa, temporal lobe encephalocele protruding into the lateral extension of the sphenoid sinus, and cerebrospinal fluid (CSF) collection on the right side of the sphenoid sinus. The transcranial approach was performed for resection of the encephalocele and obliteration of the cranial base defect anterolateral to the foramen spinosum with transcranial multilayered closure of the defect using autologous fat, cranial bone graft, and vascularized split temporal muscle. At 1-year follow up, the CSF rhinorrhea had not recurred. Transcranial multilayered closure of the defect is safe and reliable, particularly for large CSF fistula at the far lateral sphenoid sinus.