Supraorbital keyhole approach for removal of midline anterior cranial fossa meningiomas: a series of 20 consecutive cases

The classical supraorbital minicraniotomy to approach the areas of origin of anterior skull base meningiomas: Anatomical nuances influencing accessibility, operability, and frontal lobe retraction

Background

The classical supraorbital minicraniotomy (cSOM) constitutes a minimally invasive alternative for the resection of anterior skull base meningiomas (ASBM). Surgical success depends strongly on optimal patient selection and surgery planning, for which a careful assessment of tumor characteristics, approach trajectory, and bony anterior skull base anatomy is required. Still, morphometrical studies searching for relevant anatomical factors with surgical relevance when intending a cSOM for ASBM resection are lacking.

Methods

Bilateral cSOM was done in five formaldehyde-fixed heads toward the areas of origin of ASBM. Morphometrical data with potential relevant surgical implications were analyzed.

Results

The more tangential position of the cSOM with respect to the olfactory groove (OG) led to a reduction in surgical freedom (SF) in this area compared to others (P < 0.0001). Frontal lobe retraction (FLR) was also higher when approaching the OG (P < 0.05). Olfactory nerve mobilization was higher when accessing the planum sphenoidale (PS), tuberculum sellae (TS), and anterior clinoid process (ACP) (P < 0.0001). OG depth and the slope of the sphenoid bone between the PS and TS predicted lower SF and higher frontal retraction requirements along the OG and TS, respectively (P < 0.05). In contrast, longer distances to the ACP tip predicted lower SF over this structure (P < 0.01).

Conclusion

Although clinical validation is still needed, the present anatomical data suggest that assessing minicraniotomy's position/extension, OG depth, the sphenoid's slope, and distance to ACP-tip might be of particular relevance to predict FLR, maneuverability, and accessibility when considering the cSOM for ASBM resection, thus helping surgeons optimize patient selection and surgical strategy.

Fully Endoscopic Supraorbital Approach for Anterior Cranial Base Meningiomas

BACKGROUND

Anterior cranial base meningiomas include those meningiomas originating from the tuberculum sellae, the planum sphenoidale, or the olfactory groove, with surgical excision being the main treatment modality for these tumors. Conventional microscopic and endoscope-assisted versions of the supraorbital keyhole approach via an eyebrow incision emerged into minimally invasive options that are frequently utilized nowadays for treating these tumors. At the early attempts of endoscope-assisted cranial surgery, it was noted that rigid endoscopes enabled overcoming the problem of suboptimal visualization when small exposures are used. The technical specifications and design of the currently available rigid endoscopes are associated with a group of unique features that define the endoscopic view and lay the basis for its superiority over the microscopic view during brain surgery. Notwithstanding, the fully endoscopic or endoscope-controlled version of the supraorbital keyhole approach is not routinely practiced by neurosurgeons, with few series published so far. In this chapter we elaborate on the surgical technique and nuances of the fully endoscopic supraorbital approach for anterior cranial base meningiomas.

METHODS

From a prospective database of endoscopic procedures maintained by the senior author, clinical data, imaging studies, operative charts, and videos of cases undergoing fully endoscopic excision of anterior cranial base meningiomas via supraorbital approach were retrieved and analyzed. The pertinent literature was also reviewed.

RESULTS

The surgical technique of the fully endoscopic supraorbital approach for anterior cranial base meningiomas was formulated.

CONCLUSION

The fully endoscopic supraorbital approach for anterior cranial base meningiomas has many advantages over the conventional procedures. In our hands, the technique has proven to be feasible, efficient, and minimally invasive with excellent results.

Comparison of the Endoscopic Endonasal Approach with the Endoscopic Supraorbital Keyhole Approach to the Tuberculum Sellae Region: A Quantitatively Cadaveric Study

BACKGROUND

 The endoscopic endonasal approach (EEA) and the endoscopic supraorbital keyhole approach (eSKA) provide minimally invasive access to tuberculum sellae (TS) tumors. Evaluation of the operating maneuverability is helpful for approach selection. Herein, we compared the two approaches and aimed to provide quantitative anatomic data for surgical decision-making in the management of TS lesions.

METHODS

 Fifteen dissections were performed on five silicone-injected cadaveric heads. The EEA and eSKA (both right and left) were performed on each head. Surgical freedom and working angles in the axial and sagittal planes were calculated using the stereotactic navigation system in the selected six targets: the midpoint of the leading edge of the sphenoid sinus (leSS), the midpoint of the edge of the dorsum sellae (eDS), the ipsilateral medial opticocarotid recess (imOCR), the contralateral medial opticocarotid recess (cmOCR), the ipsilateral lateral opticocarotid recess (ilOCR), and the contralateral lateral opticocarotid recess (clOCR).

RESULTS

 The surgical freedom at the ilOCR and the axial working angles at the leSS, ilOCR, and imOCR (imOCR with excessive manipulation of the optic apparatus) were greater in the eSKA. The EEA provided greater surgical freedom and/or working angles at most targets than eSKA (the surgical freedom at the imOCR, cmOCR, clOCR, and eDS; the axial working angles at the cmOCR and clOCR; and the sagittal working angles at the leSS, imOCR, cmOCR, clOCR, and eDS).

CONCLUSION

 The EEA provides greater surgical freedom and working angles for paramedian lesions, whereas the eSKA provides better surgical maneuverability for lesions with lateral extension.

Cosmetic Outcomes of Supraorbital Keyhole Craniotomy Via Eyebrow Incision: A Systematic Review and Meta-Analysis

Background  Supraorbital eyebrow craniotomy is a minimally invasive alternative to a frontotemporal craniotomy and is often used for tumor and vascular pathologies. The purpose of this study was to investigate how patient cosmetic outcomes are affected by technique variations of this approach. Methods  PubMed, Embase, and Scopus databases were systematically searched, and results were reported according to PRISMA guidelines. For the meta-analysis portion, the DerSimonian-Laird random effects model was used, and the primary end points were patient satisfaction and percentage of permanent cosmetic complications. Results  A total of 2,629 manuscripts were identified. Of those, 124 studies (8,241 surgical cases) met the inclusion criteria. Overall, 93.04 ± 11.93% of patients reported favorable cosmetic outcome following supraorbital craniotomy, and mean number of cases with permanent cosmetic complications was 6.62 ± 12.53%. We found that vascular cases are associated with more favorable cosmetic outcomes than tumor cases ( p  = 0.0001). Addition of orbital osteotomy or use of a drain is associated with adverse cosmetic outcomes ( p  = 0.001 and p  = 0.0001, respectively). The location of incision, size of craniotomy, utilization of an endoscope, method of cranial reconstruction, skin closure, use of antibiotics, and addition of pressure dressing did not significantly impact cosmetic outcomes ( p  > 0.05 for all). Conclusions  Supraorbital craniotomy is a minimally invasive technique associated with generally high favorable cosmetic outcomes. While certain techniques used in supraorbital keyhole approach do not pose significant cosmetic risks, utilization of an orbital osteotomy and the addition of a drain correlate with unfavorable cosmetic outcomes.

Endoscopic Supraorbital Eyebrow Approach for Medium-Sized Tuberculum Sellae Meningiomas: A Cadaveric Stepwise Dissection, Technical Nuances, and Surgical Outcomes

BACKGROUND

Tuberculum sellae meningiomas (TSMs) have traditionally been removed using a transcranial approach. In recent years, endoscopic surgery for TSMs has been reported with an expansion of indications.

OBJECTIVE

We have performed a fully endoscopic supraorbital keyhole approach for small to medium-sized TSMs and performed radical tumor removal similar to conventional transcranial procedure. We report the details of this surgical procedure including cadaveric stepwise dissection and initial surgical results for small to medium-sized TSMs.

METHODS

We used an endoscopic supraorbital eyebrow approach for 6 patients with TSMs between September 2020 and September 2022. Mean tumor diameter was 16.0 mm (range, 10-20 mm). The surgical approach included an eyebrow skin incision ipsilateral to the lesion, a small frontal craniotomy, subfrontal exposure of the lesion, removal of the tuberculum sellae, unroofing of the optic canal, and resection of the tumor. The extent of resection, preoperative and postoperative visual function, complications, and operative time were evaluated.

RESULTS

Optic canal involvement was observed in all patients. Two patients (33%) showed visual dysfunction before surgery. Simpson grade 1 tumor resection was achieved in all cases. Visual function was improved in 2 cases, and remained unchanged in 4 cases. Postoperative pituitary function was preserved in all cases, with no decreases in olfaction.

CONCLUSIONS

The endoscopic supraorbital eyebrow approach for TSMs allowed resection of the lesion, including tumor extending to the optic canal, with a good surgical view. This technique is minimally invasive for patients and may represent a good surgical option for medium-sized TSMs.

Surgical Limitations of the Microscopic Transciliary Supraorbital Keyhole Approach to the Anterior and Middle Skull Base

BACKGROUND

The microscopic transciliary SupraOrbital keyhole (mtSO) approach has been used for a wide variety of anterior and middle fossa pathologies, including aneurysms, meningiomas, craniopharyngiomas, and other skull-base tumors. Several clinical series have proven its efficacy and safety, but detailed anatomical demarcations of the anterior and middle cranial base exposure are lacking. Our aim was to define the surgical limitations of the mtSO approach to the ipsilateral and contralateral anterior and middle skull base.

METHODS

Five cadaveric specimens (10 sides) were studied with image guidance to illustrate the limits of the surgical exposure. In addition, 30 dry skulls were used to measure the working distances between the craniotomy and key bony landmarks of the mtSO approach.

RESULTS

Surgical exposure at the anterior skull base covered the area between the medial half of the contra- and the medial two-thirds of the ipsilateral sphenoid wing including both optic nerves and interoptic space. The anterior limit at the midline was the sphenoethmoidal suture. Ipsilateral anterior clinoidectomy permitted exposure of the superior orbital fissure, which defined the anteromedial limit at the middle fossa, whereas the anterolateral limit was defined by the ophthalmic branch of the trigeminal nerve. Moreover, the posteromedial and posterolateral limits were the posterior clinoid process and the petrous ridge, respectively.

CONCLUSIONS

Our findings define the surgical limitations of the mtSO approach for the treatment of anterior and middle cranial base pathologies. These limits can be reliably identified on imaging studies allowing assessment of exposure to guide preoperative case selection.

Olfactory Groove Meningiomas: Comprehensive assessment between the different microsurgical transcranial approaches and the Endoscopic Endonasal Approaches, systematic review and metanalysis on behalf of the EANS skull base section

•OGM surgery is much more complex than a simple debate of "from above or from below" (transcranial vs endoscopic).•Lateral Sub-frontal and Superior Interhemispheric seem the most effective, superior and versatile approaches for OGM.•Minimally Invasive Transcranial approaches showed no inferiority in OGM sized <4 ​cm.•Endoscopic Endonasal Approaches showed inferior results in surgical and in functional outcomes for OGM.

Risk Factors for Postoperative Brain Contusion and Early Outcomes in Patients with Anterior Skull Base Meningiomas Undergoing Unifrontal Surgery: Single Center Experience with 110 Patients

Background

Though frontal lobe contusion is a major cause for morbidity and prolonged hospitalization following excision of anterior skull base meningiomas, there is only limited literature on this complication. This study aimed to find out the incidence of postoperative frontal lobe contusion, identify the risk factors for its development and its impact on early postoperative outcome.

Methods

Data from 110 patients who underwent excision of anterior skull base meningiomas through a unilateral supraorbital craniotomy from 2001 to 2018 were retrospectively analyzed. The risk factors analyzed for development of postoperative contusion were tumor location, size, volume, peritumoral edema, tumor consistency, extent of resection, tumor grade and type of retraction used.

Results

Simpson grade II excision was achieved in ninety-two patients (83.6%). There was no frontal lobe contusion in eighty-two patients (74.5%). Frontal lobe contusion was noted in twenty-eight patients (25.5%), but was severe in only four patients (3.6%). On multivariate analysis, fixed retractor use (OR 11.56 [1.21-110.03]; P =0.03) and WHO grade II tumor (OR 3.29 [1.11-9.77]; P =0.03) were independently associated with postoperative frontal lobe contusion. Patients with higher contusion grade had significantly longer postoperative hospitalization (P =.02) and lower KPS score at discharge (P =.01).

Conclusions

Unilateral supraorbital craniotomy and lateral subfrontal approach is an excellent procedure for excision of anterior skull base meningiomas with minimal postoperative complications related to frontal lobe retraction. Frontal lobe contusion should be avoided with the use of dynamic retraction, since postoperative contusion prolongs hospitalization and worsens the functional outcome at discharge.

The Endoscopic-Assisted Supraorbital Approach for Resection of Anterior Skull Base Meningiomas: A Large Single-Center Retrospective Surgical Study

Objective The endoscopic-assisted supraorbital approach (eSOA) constitutes a minimally invasive strategy for removing anterior skull base meningiomas (ASBM). We present the largest retrospective single-institution and long-term follow-up study of eSOA for ASBM resection, providing further insight regarding indication, surgical considerations, complications, and outcome.

Methods We evaluated data of 176 patients operated on ASBM via the eSOA over 22 years.

Results Sixty-five tuberculum sellae (TS), 36 anterior clinoid (AC), 28 olfactory groove (OG), 27 planum sphenoidale, 11 lesser sphenoid wing, seven optic sheath, and two lateral orbitary roof meningiomas were assessed. Median surgery duration was 3.35 ± 1.42 hours, being significantly longer for OG and AC meningiomas (p <0.05). Complete resection was achieved in 91%. Complications included hyposmia (7.4%), supraorbital hypoesthesia (5.1%), cerebrospinal fluid fistula (5%), orbicularis oculi paresis (2.8%), visual disturbances (2.2%), meningitis (1.7%) and hematoma and wound infection (1.1%). One patient died due to intraoperative carotid injury, other due to pulmonary embolism. Median follow-up was 4.8 years with a tumor recurrence rate of 10.8%. Second surgery was chosen in 12 cases (10 via the previous SOA and two via pterional approach), whereas two patients received radiotherapy and in five patients a wait-and-see strategy was adopted.

Conclusion The eSOA represents an effective option for ASBM resection, enabling high complete resection rates and long-term disease control. Neuroendoscopy is fundamental for improving tumor resection while reducing brain and optic nerve retraction. Potential limitations and prolonged surgical duration may arise from the small craniotomy and reduced maneuverability, especially for large or strongly adherent lesions.

Supraorbital Keyhole Craniotomy via Eyebrow Incision: A Systematic Review and Meta-Analysis

BACKGROUND

Supraorbital eyebrow keyhole craniotomy is a minimally invasive alternative to a frontotemporal craniotomy and is often used for tumor resection and aneurysm clipping. The purpose of this study is to provide a contemporary review on the outcomes related to this approach and to determine whether they vary with the type of pathology and the addition of an endoscope.

METHODS

PubMed, Embase, and Scopus databases were systematically searched, and results were reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. For the meta-analysis portion, the DerSimonian-Laird random effects model was used.

RESULTS

A total of 2629 manuscripts were identified. of those, 124 studies (8241 surgical cases) met the inclusion criteria. Mean total complication rate was 26.7 ± 25.7% and the mean approach-related mortality rate was 1.3 ± 2.8%. Technical success, defined as gross total tumor resection or complete aneurysm clipping, was achieved in 83.6 ± 21.5% of the cases. Vascular pathologies were associated with greater technical success, lower total complications, and longer length of hospital stay compared with tumor cases (P < 0.05 for all). For vascular cases, addition of the endoscope yielded lower technical success (P = 0.001) and lower complication rate (P = 0.041). The use of the endoscope for tumor pathologies did not affect technical success, complications, mortality, length of hospital stay, operative time, or reoperation rate (P > 0.05).

CONCLUSIONS

The supraorbital craniotomy via an eyebrow incision is a feasible minimally invasive approach with an overall high technical success rate for both vascular and tumor pathologies.

Keyhole Superior Interhemispheric Approach to Midline Meningiomas of the Far Frontal Region of the Anterior Skull Base: Cadaveric Study and Illustrative Cases

OBJECTIVE

Unique challenges can present in the treatment of small to mid-sized meningiomas that arise from the region of the anterior most aspect of the falx cerebri including its junction with the anterior skull base, what we call the far frontal region. Although this region of the anterior skull base is considered in the surgical approach of olfactory groove meningiomas invading this space, important differences exist between these tumors and those of the far frontal region.

METHODS

Toward refining surgical selection, our cadaveric study details a minimally invasive keyhole superior interhemispheric approach to the far frontal region and 2 illustrative cases show the feasibility of this approach.

RESULTS

Our cadaveric study defines 5 steps of the approach from the incision, craniectomy, dural opening, approaching the skull base and ipsilateral exposure, and finally falcine resection and bilateral skull base exposure. Two illustrative cases with the approach confirmed visualization of the full extent of tumor and gross total resection with preservation of the unaffected olfactory bulb.

CONCLUSIONS

To the best of our knowledge, our anatomic study is distinctively unique in quantifying the working distance of the keyhole superior interhemispheric exposure and refining visualization of the far frontal region. We discuss these benefits and limitations (i.e., substantial involvement of tumor beyond midline) and differences with large meningiomas of the olfactory groove and far frontal region with significant posterior or lateral extension for which conventional exposures are appropriate.

The endoscope-assisted supraorbital "keyhole" approach for anterior skull base meningiomas: an updated meta-analysis

INTRODUCTION

The gold-standard treatment for symptomatic anterior skull base meningiomas is surgical resection. The endoscope-assisted supraorbital "keyhole" approach (eSKA) is a promising technique for surgical resection of olfactory groove (OGM) and tuberculum sellae meningioma (TSM) but has yet to be compared with the microscopic transcranial (mTCA) and the expanded endoscopic endonasal approach (EEA) in the context of existing literature.

METHODS

An updated study-level meta-analysis on surgical outcomes and complications of OGM and TSM operated with the eSKA, mTCA, and EEA was conducted using random-effect models.

RESULTS

A total of 2285 articles were screened, yielding 96 studies (2191 TSM and 1510 OGM patients). In terms of effectiveness, gross total resection incidence was highest in mTCA (89.6% TSM, 91.1% OGM), followed by eSKA (85.2% TSM, 84.9% OGM) and EEA (83.9% TSM, 82.8% OGM). Additionally, the EEA group had the highest incidence of visual improvement (81.9% TSM, 54.6% OGM), followed by eSKA (65.9% TSM, 52.9% OGM) and mTCA (63.9% TSM, 45.7% OGM). However, in terms of safety, the EEA possessed the highest cerebrospinal fluid leak incidence (9.2% TSM, 14.5% OGM), compared with eSKA (2.1% TSM, 1.6% OGM) and mTCA (1.6% TSM, 6.5% OGM). Finally, mortality and intraoperative arterial injury were 1% or lower across all subgroups.

CONCLUSIONS

In the context of diverse study populations, the eSKA appeared not to be associated with increased adverse outcomes when compared with mTCA and EEA and offered comparable effectiveness. Case-selection is paramount in establishing a role for the eSKA in anterior skull base tumours.

Eyebrow supraorbital keyhole craniotomy for olfactory groove meningiomas with endoscope assistance: case series and systematic review of extent of resection, quantification of postoperative frontal lobe injury, anosmia, and recurrence

BACKGROUND

Olfactory groove meningiomas (OGMs) are commonly treated with open craniotomy. Endonasal approaches have also been described.

OBJECTIVE

To present clinical and radiographic outcomes for the minimally invasive eyebrow incision supraorbital keyhole approach with endoscopic assistance for OGMs.

METHODS

We performed a retrospective single-center cohort study and a systematic literature review.

RESULTS

Fifteen patients were identified, all with Grade I meningiomas. Radiographic gross total resection of enhancing tumor was achieved in all patients. Mean frontal lobe fluid-attenuated inversion recovery volume decreased from 11.1 ± 18.3 cm³ preoperatively to 9.9 ± 11.4 cm³ immediately postoperatively, and there was minimal new restricted diffusion (3.2 ± 2.2 cm³; max 7.5 cm³). Median length of stay was 3 days (range 2-8). Vision was improved in 4 (80%) and stable in 1 (20%) of 5 patients with a preoperative deficit. New postoperative anosmia occurred in 3 (23%) of 13 patients with any preoperative olfaction. All patients were satisfied with their cosmetic result at 3 months. After a median follow-up of 32.2 months, there were 2 (13.3%) asymptomatic radiographic recurrences, 1 treated with radiosurgery and the other with endoscopic endonasal approach (EEA). No patients required further craniotomy. Systematic review revealed the present series to be the largest to date reporting disaggregated outcomes for the eyebrow approach to OGM.

CONCLUSION

The eyebrow incision supraorbital keyhole craniotomy with endoscopic assistance is a safe and effective approach to OGM with tumor control rates similar to more invasive open approaches and better than the endonasal approach. Rates of frontal lobe injury, CSF leak and anosmia are comparatively low.

The endoscopic transpterional port approach: anatomy, technique, and initial clinical experience

OBJECTIVE

The evolution of microsurgical and endoscopic techniques has allowed the development of less invasive transcranial approaches. The authors describe a purely endoscopic transpterional port craniotomy to access lesions involving the cavernous sinus and the anterolateral skull base.

METHODS

Through single- or dual-port incisions and with direct endoscopic visualization, the authors performed an endoscopic transpterional port approach (ETPA) using a 4-mm straight endoscope in 8 sides of 4 formalin-fixed cadaveric heads injected with colored latex. A main working port incision is made just below the superior temporal line and behind the hairline. An optional 0.5- to 1-cm second skin port incision is made on the lateral supraorbital region, allowing multiangle endoscopic visualization and maneuverability. A 1.5- to 2-cm craniotomy centered over the pterion is done through the main port, which allows an extradural exposure of the cavernous sinus region and extra/intradural exposure of the frontal and temporal cranial fossae. The authors present a pilot surgical series of 17 ETPA procedures and analyze the surgical indications and clinical outcomes retrospectively.

RESULTS

The initial stage of this work on cadavers provided familiarity with the technique, standardized its steps, and showed its anatomical limits. The clinical ETPA was applied to gain access into the cavernous sinus, as well as for aneurysm clipping and meningioma resection. Overall, perioperative complications occurred in 1 patient (6%), there was no mortality, and at last follow-up all patients had a modified Rankin Scale score of 0 or 1.

CONCLUSIONS

The ETPA provides a less invasive, focused, and direct route to the cavernous sinus, and to the frontal and temporal cranial fossae, and it is feasible in clinical practice for selected indications with good results.

Surgical management of Tuberculum sellae Meningiomas: Myths, facts, and controversies

BACKGROUND

The optimal management of tuberculum sellae (TS) meningiomas, especially the surgical strategy, continues to be debated along with several controversies that persist.

METHODS

A task force was created by the EANS skull base section committee along with its members and other renowned experts in the field to generate recommendations for the surgical management of these tumors on a European perspective. To achieve this, the task force also reviewed in detail the literature in this field and had formal discussions within the group.

RESULTS

The constituted task force dealt with the practice patterns that exist with respect to pre-operative radiological investigations, ophthalmological and endocrinological assessments, optimal surgical strategies, and follow-up management.

CONCLUSION

This article represents the consensually derived opinion of the task force with respect to the surgical treatment of tuberculum sellae meningiomas. Areas of uncertainty where further clinical research is required were identified.

Current decision-making in meningiomas

The incidence of meningiomas is rising and the number of incidental cases is increasing steadily. The efficiency and the safety of each treatment strategy are also improving over time. Therefore the indications to treat meningiomas are constantly changing. The aim of meningioma treatment is keeping the patient fully functional while achieving long-term relief or prevention from problems related to intracranial tumor growth. This chapter reviews the natural history and treatment results and aims to put together the information for the most objective decision-making in treating meningiomas. Factors acting on the treatment decision such as anatomical localization, symptomatology, variations in tumor biology, recurrence status, age and co-morbidities, operative gains, and patient preference are individually discussed.

Supraorbital keyhole approach: Pure endoscopic and endoscope-assisted perspective

OBJECTIVE

To assess the assumed advantages of pure endoscopic and endoscope-assisted methods for the supraorbital keyhole approach. The aim is to demonstrate visibility and accessibility of the pure endoscope approach as a possible standard approach for the supraorbital keyhole approach.

PATIENTS AND METHODS

We performed eight dissections on four cadaver heads using an operating microscope, an endoscope, and neuronavigation. The visibility and accessibility of the anterior and middle cranial fossae regions were compared for each. Special structures were defined to assess their preservation in both approaches. We used pure endoscopy on the eight sides and with a microscope on those same eight sides. Accessibility was quantified for key structures using linear measurements taken with the navigation system. In addition, we present clinical cases in which an endoscope-assisted supraorbital approach was employed.

RESULTS

Our measurements have been reported for each side in the formalin-fixed heads as the mean ± SD (in mm) from the bone margin to selected regions. Moreover, image analysis was performed using ImageJ software to compare selected surface area measurements between the endoscope and microscope images on each side for all cadaveric available specimens. There were no significant statistical differences between visualization of the selected areas. This means that by visual analysis both endoscopic and microscopic images can provide the surgeon nearly the same visibility and accessibility of a selected region.

CONCLUSION

A pure endoscopic method can be used to conduct the supraorbital keyhole approach when the endoscope is used as a primary tool. Our recommendation is to use the measurements described in this study for preoperative planning of the keyhole approach. We believe that with advances in neuro-endoscope technology, and instrumentations, the endoscopic approach may replace the microscopic approach in the near future.

Decision-making algorithm for minimally invasive approaches to anterior skull base meningiomas

OBJECTIVE Anterior skull base meningiomas are benign lesions that cause neurological symptoms through mass effect on adjacent neurovascular structures. While traditional transcranial approaches have proven to be effective at removing these tumors, minimally invasive approaches that involve using an endoscope offer the possibility of reducing brain and nerve retraction, minimizing incision size, and speeding patient recovery; however, appropriate case selection and results in large series are lacking. METHODS The authors developed an algorithm for selecting a supraorbital keyhole minicraniotomy (SKM) for olfactory groove meningiomas or an expanded endoscopic endonasal approach (EEA) for tuberculum sella (TS) or planum sphenoidale (PS) meningiomas based on the presence or absence of olfaction and the anatomical extent of the tumor. Where neither approach is appropriate, a standard transcranial approach is utilized. The authors describe rates of gross-total resection (GTR), olfactory outcomes, and visual outcomes, as well as complications, for 7 subgroups of patients. Exceptions to the algorithm are also discussed. RESULTS The series of 57 patients harbored 57 anterior skull base meningiomas; the mean tumor volume was 14.7 ± 15.4 cm³ (range 2.2-66.1 cm³), and the mean follow-up duration was 42.2 ± 37.1 months (range 2-144 months). Of 19 patients with olfactory groove meningiomas, 10 had preserved olfaction and underwent SKM, and preservation of olfaction in was seen in 60%. Of 9 patients who presented without olfaction, 8 had cribriform plate invasion and underwent combined SKM and EEA (n = 3), bifrontal craniotomy (n = 3), or EEA (n = 2), and one patient without both olfaction and cribriform plate invasion underwent SKM. GTR was achieved in 94.7%. Of 38 TS/PS meningiomas, 36 of the lesions were treated according to the algorithm. Of these 36 meningiomas, 30 were treated by EEA and 6 by craniotomy. GTR was achieved in 97.2%, with no visual deterioration and one CSF leak that resolved by placement of a lumbar drain. Two patients with tumors that, based on the algorithm, were not amenable to an EEA underwent EEA nonetheless: one had GTR and the other had a residual tumor that was followed and removed via craniotomy 9 years later. CONCLUSIONS Utilizing a simple algorithm aimed at preserving olfaction and vision and based on maximizing use of minimally invasive approaches and selective use of transcranial approaches, the authors found that excellent outcomes can be achieved for anterior skull base meningiomas.

Transsphenoidal versus Transcranial Approach for Treatment of Tuberculum Sellae Meningiomas: A Systematic Review and Meta-analysis of Comparative Studies

There is controversy regarding the surgical route selection for tuberculum sellae meningiomas (TSMs): the transsphenoidal (TS) or transcranial (TC) approach? We conducted a systematic review and meta-analysis to compare clinical outcomes and postoperative complications between two surgical approaches. Literature search was performed. Relevant articles were selected and evaluated. Data were extracted and analyzed. Eight articles comprising 550 patients met the inclusion criteria. Traditionally, the rates of gross total resection, tumor recurrence, visual improvement, and cerebrospinal fluid leakage were the most common outcomes of interest. We demonstrated that the TS approach was significantly associated with better visual outcomes but more frequent cerebrospinal fluid leakage, while the rates of tumor resection and recurrence showed no significant difference between groups. In addition to surgical results that were consistent with previous studies, we further evaluated the impact of approach selection on common postoperative complications, which were closely related to the recovery course and quality of life. We revealed that the risk of dysosmia was significantly higher in the TS group. There was no significant difference between groups regarding infection, intracranial hemorrhage, and endocrine disorders. Because of the relatively low evidence levels of included retrospective studies, it was difficult to reach a categorical conclusion about the optimal surgical approach for TSMs. Finally, we recommended that the TS approach was an alternative option in patients with smaller TSMs (<30 mm) and limited invasion of optic canals in experienced neurosurgical centers.

Surgical outcome of tuberculum sellae and planum sphenoidale meningiomas based on Sekhar-Mortazavi Tumor Classification

BACKGROUND

Results from surgical series of tuberculum and planum sphenoidale meningiomas tends to be heterogeneous. Sekhar-Mortazavi tumor classification system has been recently proposed in order to predict the surgical risk and outcome.

METHODS

We retrospectively reviewed a consecutive series of tuberculum and planum sphenoidale meningioma operated at our institution between 2009 and 2016. Sekhar-Mortazavi Tumor Classification was applied to classify these tumors and evaluate the outcome.

RESULTS

Twenty-seven patients were included in the study. There were 22 females (81%) and 5 males (19%). The mean age was 54 years (range 33-78). According to Sekhar-Mortazavi Tumor Classification: 14 patients (51.85%) were class I, 11 (40.74%) patients were in class II and 2 patients (7.41%) were in class III. Twenty-one patients (77.7%) presented with visual symptoms and deficits at preoperative neuro-ophthalmological examination. Sekhar-Mortazavi class I tumors had a postoperative visual improvement in 77.7% of cases while patients in Sekhar-Mortazavi class II-III had a postoperative visual improvement in 66.6% of cases (P=0.5). No patient had deterioration of optic nerve/chiasmal function following surgery. Gross total resection was obtained in 25 patients (92.5%) without any significative difference between class I and Class II-III tumors. Permanent endocrine dysfunction was observed only in one patient in SM Class II tumor. 3 patients (11%) showed a postoperative persistent cranial nerve deficit (2 patients were anosmic and one patient had a trochlear nerve deficit). None of the patients showed postoperative CSF leak. No onset of new seizures was observed postoperatively. There was no mortality or major morbidity in this series.

CONCLUSIONS

Transcranial surgery provided very satisfying results with respect to visual and endocrine outcomes with very low surgical morbidity. The Sekhar-Mortazavi classification showed a trend towards better visual outcomes in Class I tumors. The classification system is easy to apply and could therefore prove useful to compare results between studies reported in literature, especially when comparisons are made between transcranial and endonasal surgery.

[A supraorbital trans-eyebrow approach in surgery of chiasmatic-sellar and anterior cranial fossa tumors]

OBJECTIVE

to analyze 31 resections of chiasmatic-sellar region (CSR) and anterior cranial fossa (ACF) tumors using the supraorbital trans-eyebrow approach (STA).

MATERIAL AND METHODS

We analyzed medical histories of 31 patients who underwent tumor resection using STA in the period between October 2013 and April 2017. We analyzed the age and gender of patients, size and location of the tumor, presence of a neurological deficit, vision and olfactory functions before and after surgery, surgery duration, amount of intraoperative blood loss, rate of frontal sinus trephination and nasal liquorrhea, hemorrhagic and ischemic complications after surgery, Simpson grade of tumor resection, patient's condition before and after surgery (Glasgow Outcome Scale and Karnofsky Scale), and degree of patient satisfaction with the cosmetic result of surgery. A total of 26 meningiomas (20 sphenoid plate, tubercle, and diaphragm tumors, 3 lesser sphenoid wing meningiomas, 2 orbital roof tumors, and 1 anterior clinoid process meningioma), 3 frontal lobe gliomas, and 2 pituitary adenomas were resected.

RESULTS

In all 31 operations, the approach was adequate and enabled tumor resection without lethal outcomes. The mean surgery duration was 174.6±64.4 min. The mean blood loss was 190±96.6 mL (50-380 mL). After surgery, none of the patients developed motor deficits and new epileptic seizures. Neurological deficit aggravation in the form of impaired vision and mental disorders occurred in 8 (25.8%) patients. Vision impaired in 4 (12.9%) patients, improved in 6 (19.3%) patients, and remained unchanged in 21 (67.7%) patients. An endocrinological deficit in the form of partial hypopituitarism developed in 3 (9.6%) patients; in 4 (12.9%) patients, there were mental disorders that regressed by the end of the first month of therapy. There were no intracerebral and subarachnoid hemorrhages. In 2 (6.4%) patients, small epidural hematomas were diagnosed, which did not require surgical treatment. There were only good outcomes (a GOS score of 4 or 5). After surgery, the median Karnofsky index in the STA group was 90±7. In all 31 (100%) patients, the postoperative wound healed by primary intention, without infectious complications and wound liquorrhea. One (4%) patient developed eyebrow palsy; 3 (12%) patients had hypoesthesia in the supraorbital region. The mean VAS score of patient satisfaction with the cosmetic result was 9.36 (median 10±1). The mean follow-up period was 16.2±13.5 months (2-38 months).

CONCLUSION

The STA is adequate for removal of CSR and ACF tumors under proper selection of patients. It provides an adequate view of anatomical structures and enables successful tumor resection through a less traumatic access.

Limitations of the endonasal endoscopic approach in treating olfactory groove meningiomas. A systematic review

OBJECTIVE

To review current management strategies for olfactory groove meningioma (OGM)s and the recent literature comparing endoscopic endonasal (EEA) with traditional transcranial (TCA) approaches.

METHODS

A PubMed search of the recent literature (2011-2016) was performed to examine outcomes following EEA and TCA for OGM. The extent of resection, visual outcome, postoperative complications and recurrence rates were analyzed using percentages and proportions, the Fischer exact test and the Student's t-test using Graphpad PRISM 7.0Aa (San Diego, CA) software.

RESULTS

There were 444 patients in the TCA group with a mean diameter of 4.61 (±1.17) cm and 101 patients in the EEA group with a mean diameter of 3.55 (± 0.58) cm (p = 0.0589). GTR was achieved in 90.9% (404/444) in the TCA group and 70.2% (71/101) in the EEA group (p < 0.0001). Of the patients with preoperative visual disturbances, 80.7% (21/26) of patients in the EEA cohort had an improvement in vision compared to 12.83%(29/226) in the TCA group (p < 0.0001). Olfaction was lost in 61% of TCA and in 100% of EEA patients. CSF leaks and meningitis occurred in 25.7% and 4.95% of EEA patients and 6.3% and 1.12% of TCA patients, respectively (p < 0.0001; p = 0.023).

CONCLUSIONS

Our updated literature review demonstrates that despite more experience with endoscopic resection and skull base reconstruction, the literature still supports TCA over EEA with respect to the extent of resection and complications. EEA may be an option in selected cases where visual improvement is the main goal of surgery and postoperative anosmia is acceptable to the patient or in medium-sized tumors with existing preoperative anosmia. Nevertheless, based on our results, it seems more prudent at this time to use TCA for the majority of OGMs.

Frontobasal Midline Meningiomas: Is It Right To Shed Doubt on the Transcranial Approaches? Updates and Review of the Literature

BACKGROUND

Traditionally, the surgical removal of tuberculum sellae meningioma (TSM) and olfactory groove meningioma (OGM) requires transcranial approaches and microsurgical techniques, but in the last decade endoscopic expanded endonasal approaches have been introduced: transcribriform for OGMs and transtuberculum-transplanum for TSM. A comparative analysis of the literature concerning the two types of surgical treatment of OGMs and TSM is, however, difficult.

METHODS

We conducted a literature search using the PubMed database to compare data for endoscopic and microsurgical techniques in the literature. We also conducted a retrospective analysis of selected cases from our series presenting favorable characteristics for an endoscopic approach, based on the criteria of operability of these lesions as generally accepted in the literature, and we compared the results obtained in these patients with those in the endoscopic literature.

RESULTS

We believe that making the sample more homogeneous, the difference between microsurgical technique and endoscopic technique is no longer so striking. A greater radical removal rate, a reduced incidence of cerebrospinal fluid fistula and, especially, the possibility of removing lesions of any size are advantages of transcranial surgery; a higher percentage of improvement in visual outcome and a lower risk of a worsening of a pre-existing deficit or onset of a new deficit are advantages of the endoscopic technique.

CONCLUSION

At present, the microsurgical technique is still the gold standard for the removal of the anterior cranial fossa meningiomas of all sizes, and the endoscopic technique remains a second option in certain cases.

Fully endoscopic supraorbital keyhole approach to the anterior cranial base: A cadaveric study

Introduction:

The supraorbital keyhole approach for anterior cranial base lesions has been increasingly used in clinical practice. Anatomical studies focusing on the endoscopic anatomy via this approach are few, although the microscopic anatomy has been well studied. The aim of this study is to describe the anatomical features and surgical exposure provided by the endoscopic supraorbital keyhole approach using quantitative measurements.

Materials and Methods:

Nine formalin-fixed human cadavers from the inventory of the Anatomy department were used. A total of 18 supraorbital keyhole cranitomies were conducted. The distances between the target anatomical structures and the dura mater at the craniotomy site, and the distances between deep anatomical structures were measured with purpose-designed hooks.

Results:

The distance between the dura mater and optic canal was measured as 69.5 ± 6.7 mm (62–83 mm); optic chiasm as 76.2 ± 5.4 mm (67–86 mm); anterior communicating artery as 82.6 ± 6.1 mm (71–93 mm); internal carotid artery (ICA) bifurcation as 74.7 ± 6.0 mm (66–84 mm) and the basilar tip as 94.9 ± 7.0 mm (87–111 mm). The mean diameter of the optic canal was 7.4 ± 1.3 mm (6–11 mm), whereas the mean diameter of diaphragma sellae was measured as 8.4 ± 1.1 mm (7–10 mm).

Conclusions:

The results of this study showed that the anterior and medial aspects of the anterior cranial fossa can be visualized properly. Dissection of the ipsilateral arteries of Circle of Willis can be performed easily using an endoscopic supraorbital keyhole approach.

Septal transposition: a novel technique for preservation of the nasal septum during endoscopic endonasal resection of olfactory groove meningiomas

Endonasal resection of olfactory groove meningiomas allows for several advantages over transcranial routes, including a direct approach to the bilateral anterior cranial base and dura mater, early tumor devascularization, and avoidance of brain retraction. Although considered minimally invasive, the endoscopic approach to the cribriform plate typically requires resection of the superior nasal septum, resulting in a large superior septal perforation. The septal transposition technique improves preservation of sinonasal anatomy through the elimination of a septal perforation while allowing for wide exposure to the midline anterior cranial base and harvest of a nasal septal flap. Herein, the authors describe a 39-year-old female who presented with a progressively enlarging olfactory groove meningioma. An endoscopic endonasal resection with a septal transposition technique was performed. On follow-up, the nasal cavity had completely normal anatomy with preservation of the turbinates and nasal septum. The authors conclude that septal transposition is a useful technique that allows wide exposure of the anterior cranial base with maximal preservation of normal nasal anatomy and avoidance of a large septal perforation.

The supraorbital endoscopic approach for tumors

OBJECTIVE

To describe the indications, technical nuances, and techniques for complication avoidance for the supraorbital keyhole approach with endoscopic assistance. The supraorbital eyebrow craniotomy provides minimally invasive access to a wide range of frontal fossa, parasellar, and some middle and posterior fossae tumors. This approach is considered ideal for removal of many, if not most, planum and tuberculum sellae meningiomas, some olfactory groove meningiomas, and suprasellar craniopharyngiomas, particularly tumors with far lateral extensions. It is also ideal for many intraaxial tumors, including metastases and gliomas arising from the orbitofrontal, frontal pole, and medial temporal lobe regions. The use of endoscopy further extends the range and versatility of this keyhole approach and is considered an essential adjunct for allowing safe and maximal tumor removal.

A panoramic view of the skull base: systematic review of open and endoscopic endonasal approaches to four tumors

Endoscopic endonasal surgery has been established as the safest approach to pituitary tumors, yet its role in other common skull base lesions has not been established. To answer this question, we carried out a systematic review of reported series of open and endoscopic endonasal approaches to four major skull base tumors: olfactory groove meningiomas (OGM), tuberculum sellae meningiomas (TSM), craniopharyngiomas (CRA), and clival chordomas (CHO). Data from 162 studies containing 5,701 patients were combined and compared for differences in perioperative mortality, gross total resection (GTR), cerebrospinal fluid (CSF) leak, neurological morbidity, post-operative visual function, post-operative anosmia, post-operative diabetes insipidus (DI), and post-operative obesity/hyperphagia. Weighted average rates for each outcome were calculated using relative study size. Our findings indicate similar rates of GTR and perioperative mortality between open and endoscopic approaches for all tumor types. CSF leak was increased after endoscopic surgery. Visual function symptoms were more likely to improve after endoscopic surgery for TSM, CRA, and CHO. Post-operative DI and obesity/hyperphagia were significantly increased after open resection in CRA. Recurrence rates per 1,000 patient-years of follow-up were higher in endoscopy for OGM, TSM, and CHO. Trends for open and endoscopic surgery suggested modest improvement in all outcomes over time. Our observations suggest that endonasal endoscopy is a safe alternative to craniotomy and may be preferred for certain tumor types. However, endoscopic surgery is associated with higher rates of CSF leak, and possibly increased recurrence rates. Prospective study with long-term follow-up is required to verify these preliminary observations.

The anterior interhemispheric approach: a safe and effective approach to anterior skull base lesions

BACKGROUND

Many approaches to the anterior skull base have been reported. Frequently used are the pterional, the unilateral or bilateral frontobasal, the supraorbital and the frontolateral approach. Recently, endoscopic transnasal approaches have become more popular. The benefits of each approach has to be weighted against its complications and limitations. The aim of this study was to investigate if the anterior interhemispheric approach (AIA) could be a safe and effective alternative approach to tumorous and non-tumorous lesions of the anterior skull base.

METHODS

We screened the operative records of all patients with an anterior skull base lesion undergoing transcranial surgery. We have used the AIA in 61 patients. These were exclusively patients with either olfactory groove meningioma (OGM) (n = 43), ethmoidal dural arteriovenous fistula (dAVF) ( n = 6) or frontobasal fractures of the anterior midline with cerebrospinal fluid (CSF) leakage ( n = 12). Patient records were evaluated concerning accessibility of the lesion, realization of surgical aims (complete tumor removal, dAVF obliteration, closure of the dural tear), and approach related complications.

RESULTS

The use of the AIA exclusively in OGMs, ethmoidal dAVFs and midline frontobasal fractures indicated that we considered lateralized frontobasal lesions not suitable to be treated successfully. If restricted to these three pathologies, the AIA is highly effective and safe. The surgical aim (complete tumor removal, complete dAVF occlusion, no rhinorrhea) was achieved in all patients. The complication rate was 11.5 % (wound infection (n = 2; 3.2 %), contusion of the genu of the corpus callosum, subdural hygroma, epileptic seizure, anosmia and asymptomatic bleed into the tumor cavity (n = 1 each). Only the contusion of the corpus callosum was directly related to the approach (1.6 %). Olfaction, if present before surgery, was preserved in all patients, except one (1.6 %).

CONCLUSIONS

The AIA is an effective and a safe approach to tumorous, vascular and traumatic pathologies of the midline anterior skull base. This approach should be part of the armamentarium of skull base surgeons.

The Supraorbital Keyhole Craniotomy through an Eyebrow Incision: Its Origins and Evolution

In the modern era of neurosurgery, the use of the operative microscope, rigid rod-lens endoscope, and neuronavigation has helped to overcome some of the previous limitations of surgery due to poor lighting and anatomic localization available to the surgeon. Over the last thirty years, the supraorbital craniotomy and subfrontal approach through an eyebrow incision have been developed and refined to play a legitimate role in the armamentarium of the modern skull base neurosurgeon. With careful patient selection, the supraorbital "keyhole" approach offers a less invasive but still efficacious approach to a number of lesions along the subfrontal corridor. Well over 1000 cases have been reported in the literature utilizing this approach establishing its safety and efficacy. This paper discusses the nuances of this approach, including the benefits and limitations of its use described through our technique, review of the literature, and case illustration.