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Daily bibliographic review of the Neurosurgery Department. La Fe University Hospital. Valencia, Spain

Endoscopic endonasal versus transcranial approach to tuberculum sellae and planum sphenoidale meningiomas

J Neurosurg 128:40–48, 2018

Planum sphenoidale (PS) and tuberculum sellae (TS) meningiomas cause visual symptoms due to compression of the optic chiasm. The treatment of choice is surgical removal with the goal of improving vision and achieving complete tumor removal. Two options exist to remove these tumors: the transcranial approach (TCA) and the endonasal endoscopic approach (EEA). Significant controversy exists regarding which approach provides the best results and whether there is a subset of patients for whom an EEA may be more suitable. Comparisons using a similar cohort of patients, namely, those suitable for gross-total resection with EEA, are lacking from the literature.

METHODS The authors reviewed all cases of PS and TS meningiomas that were surgically removed at Weill Cornell Medical College between 2000 and 2015 (TCA) and 2008 and 2015 (EEA). All cases were shown to a panel of 3 neurosurgeons to find only those tumors that could be removed equally well either through an EEA or TCA to standardize both groups. Volumetric measurements of preoperative and postoperative tumor size, FLAIR images, and apparent diffusion coefficient maps were assessed by 2 independent reviewers and compared to assess extent of resection and trauma to the surrounding brain. Visual outcome and complications were also compared.

RESULTS Thirty-two patients were identified who underwent either EEA (n = 17) or TCA (n = 15). The preoperative tumor size was comparable (mean 5.58 ± 3.42 vs 5.04 ± 3.38 cm3 [± SD], p = 0.661). The average extent of resection achieved was not significantly different between the 2 groups (98.80% ± 3.32% vs 95.13% ± 11.69%, p = 0.206). Postoperatively, the TCA group demonstrated a significant increase in the FLAIR/edema signal compared with EEA patients (4.15 ± 7.10 vs -0.69 ± 2.73 cm3, p = 0.014). In addition, the postoperative diffusion-weighted imaging signal of cytotoxic ischemic damage was significantly higher in the TCA group than in the EEA group (1.88 ± 1.96 vs 0.40 ± 0.55 cm3, p = 0.008). Overall, significantly more EEA patients experienced improved or stable visual outcomes compared with TCA patients (93% vs 56%, p = 0.049). Visual deterioration was greater after TCA than EEA (44% vs 0%, p = 0.012). While more patients experienced postoperative seizures after TCA than after EEA (27% vs 0%, p = 0.038), there was a trend toward more CSF leakage and anosmia after EEA than after TCA (11.8% vs 0%, p = 0.486 and 11.8% vs 0%, p = 0.118, respectively).

CONCLUSIONS In this small single-institution study of similarly sized and located PS and TS meningiomas, EEA provided equivalent rates of resection with better visual results, less trauma to the brain, and fewer seizures. These preliminary results merit further investigation in a larger multiinstitutional study and may support EEA resection by experienced surgeons in a subset of carefully selected PS and TS meningiomas.

Clinical features and surgical outcomes of patients with skull base chordoma

J Neurosurg 127:1257–1267, 2017

Skull base chordoma is relatively rare, and a limited number of reports have been published regarding its clinical features. Moreover, the factors associated with extent of resection, as well as the value of marginal resection for long-term survival, are still in question for this disease. The objective of this study was to investigate these factors by evaluating their clinical features and surgical outcomes.

METHODS A retrospective analysis of 238 patients with skull base chordomas, who met the inclusion criteria, was performed. This study summarized the clinical features, selection of approaches, degree of resection, and postoperative complications by statistical description analyses; proposed modified classifications of tumor location and bone invasion; studied the contributions of the clinical and radiological factors to the extent of resection by Pearson c2, ANOVA, rank test, and binary logistic regression analysis; and estimated the differences in overall survival and progression-free survival rates with respect to therapeutic history, classification of tumor location, extent of bone invasion, and extent of tumor resection by the Kaplan-Meier method. A p value < 0.05 was considered statistically significant.

RESULTS The study included 140 male and 98 female patients with a mean age of 38.1 years. Headache and neck pain (33.2%) and diplopia (29%) were the most common initial symptoms. Sphenoclival type accounted for the largest proportion of tumor location (59.2%); endophytic chordoma was the more common type of bone invasion (81.5%). Lateral open approaches were performed in two-thirds of the study population (78.6%). The rate of marginal resection was 66%, composed of gross-total resection (11.8%) and near-total resection (54.2%). Meningitis (8%) and CSF leakage (3.8%) were the most frequent complications. The mean follow-up period was 43.7 months. The overall survival and progression-free survival rates at 5 years were 76% and 45%, respectively. Recurrent tumor and larger tumor volume (≥ 40 cm3) were identified as risk factors of marginal resection. Patients who presented with recurrent tumor and underwent intralesional resection had a worse long-term outcome.

CONCLUSIONS The classifications of both tumor location and bone invasion demonstrated clinical value. Marginal resection was more likely to be achieved for primary lesions with smaller volumes (< 40 cm3). The rate of CSF leakage declined due to improved dura mater repair with free fat grafts. Marginal resection, or gross-total resection when possible, should be performed in patients with primary chordomas to achieve better long-term survival.

Efficacy and outcomes of facial nerve–sparing treatment approach to cerebellopontine angle meningiomas

J Neurosurg 127:1231–1241, 2017

Advanced microsurgical techniques contribute to reduced morbidity and improved surgical management of meningiomas arising within the cerebellopontine angle (CPA). However, the goal of surgery has evolved to preserve the quality of the patient’s life, even if it means leaving residual tumor. Concurrently, Gamma Knife radiosurgery (GKRS) has become an acceptable and effective treatment modality for newly diagnosed, recurrent, or progressive meningiomas of the CPA. The authors review their institutional experience with CPA meningiomas treated with GKRS, surgery, or a combination of surgery and GKRS. They specifically focus on rates of facial nerve preservation and characterize specific anatomical features of tumor location with respect to the internal auditory canal (IAC).

METHODS Medical records of 76 patients with radiographic evidence or a postoperative diagnosis of CPA meningioma, treated by a single surgeon between 1992 and 2016, were retrospectively reviewed. Patients with CPA meningiomas smaller than 2.5 cm in greatest dimension were treated with GKRS, while patients with tumors 2.5 cm or larger underwent facial nerve–sparing microsurgical resection where appropriate. Various patient, clinical, and tumor data were gathered. Anatomical features of the tumor origin as seen on preoperative imaging confirmed by intraoperative investigation were evaluated for prognostic significance. Facial nerve preservation rates were evaluated.

RESULTS According to our treatment paradigm, 51 (67.1%) patients underwent microsurgical resection and 25 (32.9%) patients underwent GKRS. Gross-total resection (GTR) was achieved in 34 (66.7%) patients, and subtotal resection (STR) in 17 (33.3%) patients. Tumors recurred in 12 (23.5%) patients initially treated surgically, requiring additional surgery and/or GKRS. Facial nerve function was unchanged or improved in 68 (89.5%) patients. Worsening facial nerve function occurred in 8 (10.5%) patients, all of whom had undergone microsurgical resection. Upfront treatment with GKRS for CPA meningiomas smaller than 2.5 cm was associated with preservation of facial nerve function in all patients over a median follow-up of 46 months, regardless of IAC invasion and tumor origin. Anatomical origin was associated with extent of resection but did not correlate with postoperative facial nerve function. Tumor size, extent of resection, and the presence of an arachnoid plane separating the tumor and the contents of the IAC were associated with postoperative facial nerve outcomes.

CONCLUSIONS CPA meningiomas remain challenging lesions to treat, given their proximity to critical neurovascular structures. GKRS is a safe and effective option for managing CPA meningiomas smaller than 2.5 cm without associated mass effect or acute neurological symptoms. Maximal safe resection with preservation of neurological function can be performed for tumors 2.5 cm or larger without significant risk of facial nerve dysfunction, and, when combined with GKRS for recurrence and/or progression, provides excellent disease control. Anatomical features of the tumor origin offer critical insights for optimizing facial nerve preservation in this cohort.

Surgical resection of skull-base chordomas: experience in case selection for surgical approach according to anatomical compartments and review of the literature

Acta Neurochir (2017) 159:1835–1845

Chordoma is a rare bony malignancy known to have a high rate of local recurrence after surgery. The best treatment paradigm is still being evaluated. We report our experience and review the literature. We emphasize on the difference between endoscopic and open craniotomy in regard to the anatomical compartment harboring the tumor, the limitations of the approaches and the rate of surgical resection.

Method: We retrospectively collected all patients with skullbase chordomas operated on between 2004 and 2014. Detailed radiological description of the compartments being occupied by the tumor and the degree of surgical resection is discussed.

Results: Eighteen patients were operated on in our facility for skull-base chordoma. Seventeen endoscopic surgeries were done in 15 patients, and 7 craniotomies were done in 5 patients. The mean age was 48.9 years (±19.8 years). When reviewing the anatomical compartments, we found that the most common were the upper clivus (95.6%) and lower clivus (58.3%), left cavernous sinus (66.7%) and petrous apex (∼60%). Most of the patients had intradural tumor involvement (70.8%). In all craniotomy cases, there was residual tumor in multiple compartments. In the endoscopic cases, the most difficult compartments for total resection were the lower clivus, and lateral extensions to the petrous apex or cavernous sinus.

Conclusions: Our experience shows that the endoscopic approach is a good option for midline tumors without significant lateral extension. In cases with very lateral or lower extensions, additional approaches should be added trying to achieve complete resection.

Multimodality Treatment of Skull Base Chondrosarcomas

Neurosurgery 81:520–530, 2017

Limited data exist to guide the multimodality management of chondrosarcomas (CSAs) arising in the skull base.

OBJECTIVE : To determine the impact of histological subtype/grade on progression-free survival (PFS) and the indications for surgery, radiation, and chemotherapy based on histology.

METHODS: A retrospective review was performed of 37 patients (conventional type: 81%, mesenchymal: 16.2%, dedifferentiated: 2.7%) treated at The University of Texas M.D. Anderson Cancer Center. Of the conventional subtype, 23% were grade 1, 63% were grade 2, and 14% were grade 3. In addition to surgery, mesenchymal/dedifferentiated CSAs (18% of the cohort) underwent neoadjuvant chemotherapy and 48.6% of the overall cohort received adjuvant radiotherapy. Histological grade/subtype and treatment factors were assessed for impact on median PFS (primary outcome).

RESULTS: Conventional subtype vs mesenchymal/dedifferentiated was positively associated with median PFS (166 vs 24 months, P < .05). Increasing conventional grade inversely correlated with median PFS (P < .05). Gross total resection positively impacted PFS in conventionalCSAs (111.8 vs 42.9months, P=.201) and mesenchymal/dedifferentiated CSAs (58.2 vs 1.0 month, P < .05). Adjuvant radiotherapy significantly impacted PFS in conventional grades 2 and 3 (182 vs 79 months, P < .05) and a positive trend with mesenchymal/dedifferentiated CSAs (43.5 vs 22.0 months). Chemotherapy improved PFS for mesenchymal/dedifferentiated CSAs (50 vs 9 months, P = .089).

CONCLUSION: There is a potential need for histological subtype/grade specific treatment protocols. For conventional CSAs, surgery alone provides optimal results grade 1 CSAs, while resection with adjuvant radiotherapy yields the best outcomefor grade 2 and 3 CSAs. Improvements in PFS seen with neoadjuvant therapy in mesenchymal/dedifferentiated CSAs indicate a potential role for systemic therapies. Larger studies are necessary to confirm the proposed treatment protocols.

Optimal treatment of jugular foramen schwannomas

Acta Neurochir (2017) 159:1517–1527

The goal of treatment for jugular foramen schwannomas (JFSs) is to achieve complete tumor removal with cranial nerve preservation. However, achieving this goal remains a challenge despite the advances in microsurgical techniques. The aim of this study was to determine optimal treatment strategies for JFSs based on a review of a series of 29 surgical cases in our institute.

Materials and methods: Between 1997 and 2013, 29 patients with JFSs underwent surgical treatment by multidisciplinary otoneurosurgical approaches. We retrospectively evaluated various clinical outcomes including the extent of tumor resection, postoperative cranial nerve deficits, and the recurrence rate. Tumor extension was classified using the Kaye and Pellet classification (KPC) system, and the extent of tumor resection was graded as gross total resection (GTR), near total resection (NTR), and subtotal resection (STR). We utilized the House- Brackmann facial nerve grading system (HBFNGS), the average pure-tone audiometry and speech audiometry (PTA/SA) tests, and the American Speech-Language-Hearing Association National Outcome Measurement System (ASHA NOMS) swallowing scale (ASHA level) for assessment of functional outcomes.

Results: The extent of tumor resection was not related to the degree of immediate postoperative cranial nerve deficits. However, the surgical approach was significantly related to postoperative hearing status and immediate postoperative facial function. Also, among the ten patients who were below the level of acceptable facial function immediately postoperatively, nine patients (90%) recovered to acceptable facial function by the last follow-up. Concerning postoperative swallowing status, all 21 patients recovered swallowing function by the last follow-up. Postoperative Gamma Knife stereotactic radiosurgery (GKRS) was performed for three recurrent and seven residual tumors, and recurrence was not observed in the mean 36-month follow-up period.

Conclusions: A surgical strategy should be tailored to the individual case, and clinicians should consider the possibility of recurrence and further adjuvant treatment.

Craniotomy for perisellar meningiomas: comparison of simple (appropriate for endoscopic approach) versus complex anatomy and surgical outcomes

J Neurosurg 126:1191–1200, 2017

Microsurgical resection of perisellar meningiomas has remained the gold standard for treatment, with extended endoscopic endonasal surgery emerging as a viable alternative. Historical microsurgical series do not distinguish based on tumor anatomy, but are being used as a comparison against endonasal surgery. In this study, the authors retrospectively reviewed and compared the anatomy of perisellar meningiomas seen at their institution. The tumors were separated into 2 groups based on whether they would be appropriate for endoscopic resection, and the authors compared the surgical outcomes.

METHODS Between 2001 and 2013, 53 patients (73.6% women) with perisellar meningiomas underwent open microsurgical resection at Vancouver General Hospital performed by the senior author (R.A.). These tumors were separated into 2 groups based on their anatomy, and the authors analyzed the resection rates, surgical results, patient quality of life, and complications.

RESULTS Among the 53 patients who presented with perisellar meningiomas, the authors were able to identify 18 lesions with “simple” anatomy suitable for endoscopic resection and 35 lesions with “complex” anatomy suitable for craniotomy resection. The mean age of patients in the study cohort was 57.4 years (range 33–91 years), and most patients presented with visual loss (68.0%) and visual field restriction (64.2%). There were no major differences in patient demographic data between the 2 groups. Patients with simple anatomy had smaller lesions (2.1 vs 3.5 cm; p = 0.004), no optic canal invasion (89% vs 26%; p < 0.0001), minimal vascular encasement (cortical cuff 83% vs 9%; p < 0.0001), and a rounded tumor shape (100% vs 31.8%; p = 0.0001) when compared with those with complex anatomy. The majority of lesions originated from the tuberculum sellae and planum sphenoidale. A greater degree of resection was achieved in the favorable anatomy group (99% vs 87.1%; p < 0.0001). Vision was improved or normalized in 96.6% of patients. Patients in the cohort with complex anatomy had more transient complications; there were no incidents of surgical-site infection, meningitis, or death in this series. One patient who underwent removal of a recurrent lesion experienced a CSF leak that required endoscopic repair. The overall persisting complications rate was higher in the group with complex anatomy (11.1% vs 37.1%; p = 0.0498); overall, 28.3% of patients experienced disabling complications. Patient-perceived quality of life improved in the simple anatomy group following surgery (DSF-36 +16.6 vs -8.4; p = 0.0045).

CONCLUSIONS Extended endoscopic surgery is emerging as a viable alternative to microsurgical resection of perisellar meningiomas. The authors identified 2 patient groups based on tumor anatomy, with distinctly separate surgical outcomes. In the future, patients considered for endoscopic resection should be compared against the surgical group with simple anatomy that includes smaller tumors, no vascular encasement, and limited optic canal invasion.

 

 

Lateral Orbitotomy Approach for Lesions Involving the Middle Fossa

Neurosurgery 80:309–322, 2017

Classically used for treatment of orbital lesions,the lateral orbitotomy with cantholysis can be combined with a temporal craniectomy for lesions involving the middle cranial fossa.

OBJECTIVE: To present a single-center experience with the lateral orbitotomy approach for lesions involving the middle fossa.

METHODS: Twenty-five patients underwent lateral orbitotomies from April 2012 to July 2015. Excluding patients with solely intraorbital pathologies, 13 patients’clinical and radio- graphic records were retrospectively reviewed.

RESULTS: Signs/symptoms in the 13 patients (ages 28-81) included proptosis (69%), decreased visual acuity (31%), diplopia (54%), and afferent pupillary defect (69%). Pathologies were meningioma (8), esthesioneuroblastoma, lymphoma, chordoma, Ewing’s sarcoma, and squamous cell carcinoma. Surgical goals were maximal safe resection in 8 patients, palliative debulking in 3 patients, and cavernous sinus biopsy in 2 patients. In 8 patients for whom maximal resection was the goal, 2 had gross total resection, while 6 had near-total resection. All patients (3) for whom palliation was the goal had symptomatic improvement. Both cavernous sinus biopsies obtained diagnostic tissue without complications. All patients with proptosis (n = 9) and diplopia (n = 7), and 2 of 4 patients with decreased visual acuity had improvement in their symptoms. No patient reported worsening of their symptoms. Mean follow-up was 12 mo (2-30 mo). Complica- tions included oculorrhea (1), pseudomeningocele (2), transient ptosis (2), and forehead numbness (1).

CONCLUSION: The lateral orbitotomy is a promising approach for carefully selected lesions with involvement of both the lateral orbit and middle cranial fossa. It provides minimally invasive access for biopsy, decompression, or resection.

Occipitocervical Instability After Far-Lateral Transcondylar Surgery

Neurosurgery 80:140–145, 2017

After a far-lateral transcondylar approach, patients may maintain neutral alignment in the immediate postoperative period, but severe occipitoatlantal subluxation may occur gradually with cranial settling and possible neurological injury. Previous research is based on assumptions regarding the extent of condylar resection and the change in biomechanics that produces instability.

OBJECTIVE: To quantify the extent of bone removal during a far-lateral transcondylar approach, determine the changes in range of motion (ROM) and stiffness that occur after condylar resection, and identify the threshold of condylar resection that predicts alterations in occipitocervical biomechanics.

METHODS: Nine human cadaveric specimens were biomechanically tested before and after far-lateral transcondylar resection extending into the hypoglossal canal (HC). The extent of condylar resection was quantified using volumetric comparison between pre- and postresection computed tomography scans. ROM and stiffness testing were performed in intact and resected states. The extent of resection that produced alterations in occipitocervical biomechanics was assessed with sensitivity analysis.

RESULTS: Bone removal during condylar resection into the HC was 15.4%-63.7% (mean 35.7%). Sensitivity analysis demonstrated that changes in biomechanics may occur when just 29% of the occipital condyle was resected (area under the curve 0.80-1.00).

CONCLUSION: Changes in occipitocervical biomechanics may be observed if one-third of the occipital condyle is resected. During surgery, the HC may not be a reliable landmark to guide the extent of resection. Patients who undergo condylar resections extending into or beyond the HC require close surveillance for occipitocervical instability.

A checklist for endonasal transsphenoidal anterior skull base surgery

Intraoperative MRI for transsphenoidal pituitary surgery

J Neurosurg 124:1634–1639, 2016

Approximately 250 million surgical procedures are performed annually worldwide, and data suggest that major complications occur in 3%–17% of them. Many of these complications can be classified as avoidable, and previous studies have demonstrated that preoperative checklists improve operating room teamwork and decrease complication rates. Although the authors’ institution has instituted a general preoperative “time-out” designed to streamline communication, flatten vertical authority gradients, and decrease procedural errors, there is no specific checklist for transnasal transsphenoidal anterior skull base surgery, with or without endoscopy. Such minimally invasive cranial surgery uses a completely different conceptual approach, set-up, instrumentation, and operative procedure. Therefore, it can be associated with different types of complications as compared with open cranial surgery. The authors hypothesized that a detailed, procedure-specific, preoperative checklist would be useful to reduce errors, improve outcomes, decrease delays, and maximize both teambuilding and operational efficiency. Thus, the object of this study was to develop such a checklist for endonasal transsphenoidal anterior skull base surgery.

Methods An expert panel was convened that consisted of all members of the typical surgical team for transsphenoidal endoscopic cases: neurosurgeons, anesthesiologists, circulating nurses, scrub technicians, surgical operations managers, and technical assistants. Beginning with a general checklist, procedure-specific items were added and categorized into 4 pauses: Anesthesia Pause, Surgical Pause, Equipment Pause, and Closure Pause.

Results The final endonasal transsphenoidal anterior skull base surgery checklist is composed of the following 4 pauses. The Anesthesia Pause consists of patient identification, diagnosis, pertinent laboratory studies, medications, surgical preparation, patient positioning, intravenous/arterial access, fluid management, monitoring, and other special considerations (e.g., Valsalva, jugular compression, lumbar drain, and so on). The Surgical Pause is composed of personnel introductions, planned procedural elements, estimation of duration of surgery, anticipated blood loss and fluid management, imaging, specimen collection, and questions of a surgical nature. The Equipment Pause assures proper function and availability of the microscope, endoscope, cameras and recorders, guidance systems, special instruments, ultrasonic microdoppler, microdebrider, drills, and other adjunctive supplies (e.g., Avitene, cotton balls, nasal packs, and so on). The Closure Pause is dedicated to issues of immediate postoperative patient disposition, orders, and management.

Conclusions Surgical complications are a considerable cause of death and disability worldwide. Checklists have been shown to be an effective tool for reducing preventable errors surrounding surgery and decreasing associated complications. Although general checklists are already in place in most institutions, a specific checklist for endonasal transsphenoidal anterior skull base surgery was developed to help safeguard patients, improve outcomes, and enhance teambuilding.

Endo ICG videoangiography: localizing the carotid artery in skull-base endonasal approaches

Endo ICG videoangiography- localizing the carotid artery in skull-base endonasal approaches

Acta Neurochir (2016) 158:1351–1353

In this work, the applicability of ICG-VA to skull base endoscopic surgery and its capacity to locate the internal carotid artery are shown.

Methods: An adapted optical module to perform ICG-VA was used to perform endoscopic procedures. There were two intraoperative phases of interest that were used to evaluate the ICA: upon exposure of the skull base and during the intradural exploration.

This new tool for obtaining ICA images in real time (as opposed to with navigation), and it is demonstrated that this tool provides a superior ability to detect the margins of the ICA compared with the Doppler technique. On the other hand, the present technique also provides enhancement of the artery through the bone of the skull base without the need for drilling.

Conclusions: ICG-VA is a safe and effective technique for locating the ICA in skull-base expanded endonasal surgery. Furthermore, this technique can provide real-time guidance for the surgeon and increase safety for the patient.

Comparative analysis of outcomes following craniotomy and expanded endoscopic endonasal transsphenoidal resection of craniopharyngioma and related tumors

Endoscopic endonasal surgery for craniopharyngiomas

J Neurosurg 124:627–638, 2016

Craniopharyngiomas and similar midline suprasellar tumors have traditionally been resected via transcranial approaches. More recently, expanded endoscopic endonasal transsphenoidal approaches have gained interest. Surgeons have advocated for both approaches, and at present there is no consensus whether one approach is superior to the other. The authors therefore compared surgical outcomes between craniotomy and endoscopic endonasal transsphenoidal surgery (EETS) for suprasellar tumors treated at their institution.

Methods: A retrospective review of patients undergoing resection of suprasellar lesions at Cedars-Sinai Medical Center between 2000 and 2013 was performed. Patients harboring suspected craniopharyngioma were selected for extensive review. Other pathologies or predominantly intrasellar masses were excluded. Cases were separated into 2 groups, based on the surgical approach taken. One group underwent EETS and the other cohort underwent craniotomy. Patient demographic data, presenting symptoms, and previous therapies were tabulated. Preoperative and postoperative tumor volume was calculated for each case based on MRI. Student t-test and the chi-square test were used to evaluate differences in patient demographics, tumor characteristics, and outcomes between the 2 cohorts. To assess for selection bias, 3 neurosurgeons who did not perform the surgeries reviewed the preoperative imaging studies and clinical data for each patient in blinded fashion and indicated his/her preferred approach. These data were subject to concordance analysis using Cohen’s kappa test to determine if factors other than surgeon preference influenced the choice of surgical approach.

Results: Complete data were available for 53 surgeries; 19 cases were treated via EETS, and 34 were treated via craniotomy. Patient demographic data, preoperative symptoms, and tumor characteristics were similar between the 2 cohorts, except that fewer operations for recurrent tumor were observed in the craniotomy cohort compared with EETS (17.6% vs 42.1%, p = 0.05). The extent of resection was similar between the 2 groups (85.6% EETS vs 90.7% craniotomy, p = 0.77). An increased rate of cranial nerve injury was noted in the craniotomy group (0% EETS vs 23.5% craniotomy, p = 0.04). Postoperative CSF leak rate was higher in the EETS group (26.3% EETS vs 0% craniotomy, p = 0.004). The progression-free survival curves (log-rank p = 0.99) and recurrence rates (21.1% EETS vs 23.5% craniotomy, p = 1.00) were similar between the 2 groups. Concordance analysis of cases reviewed by 3 neurosurgeons indicated that individual surgeon preference was the only factor that determined surgical approach (kappa coefficient -0.039, p = 0.762)

Conclusions: Surgical outcomes were similar for tumors resected via craniotomy or EETS, except that more CSF leaks occurred in the EETS cohort, whereas more neurological injuries occurred in the craniotomy cohort. Surgical approach appears to mostly reflect surgeon preference rather than specific tumor characteristics. These data support the view that EETS is a viable alternative to craniotomy, providing a similar extent of resection with less neurological injury.

Surgical management of medium and large petroclival meningiomas: a single institution’s experience of 199 cases with long-term follow-up

Surgical management of medium and large petroclival meningiomas

Acta Neurochir (2016) 158:409–425

Petroclival meningiomas (PCMs) were once regarded as ‘inoperable’ due to their complex anatomy and limited surgical exposure. This study aimed to evaluate the long-term outcomes of surgically treated PCMs larger than 2 cm.

Methods A series of 199 consecutive patients (137 females, 68.8 %) with PCMs larger than 2 cm from between 1993 and 2003 were included. The clinical charts, radiographs, and follow-ups were evaluated.

Results Gross total resection (GTR) was achieved in 111 (55.8 %) patients, subtotal resection (STR) in 65, and partial resection (PR) in 23. Cranial nerve dysfunctions were the most common complications and occurred in 133 (66.8 %) cases. The surgical mortality was 2.0 %. The Karnofsky Performance Scale (KPS) scores significantly decreased 1 month after the operations (preoperative KPS=76.8 and postoperative KPS = 64.8; p = 0.011, Paired-samples t test). Long-term follow-ups were obtained in 142 patients, the follow-up duration was 171.6 months, and the most recent KPS was 83.2. Permanent morbidities remained in 24 patients (18.9 %). Multivariate analysis revealed that brainstem edema and tumors larger than 4 cm in diameter were independent risk factors in terms of outcomes (KPS < 80). The recurrence/ progression rates were 14.5, 31.8, and 53.3 % for the GTR, STR, and PR cases, respectively (p =0.002, Pearson χ2 test). Gamma Knife radiosurgery for the remnants exhibited good tumor control.

Conclusions Favorable outcomes and low mortality were achieved with the microsurgical management of medium and large PCMs; however, the rates of cranial nerves dysfunction remained high. Radically aggressive resection might not be judicious in terms of postoperative morbidity. The preoperative evaluations and intraoperative findings were informative regarding the outcomes. The low follow-up rate likely compromised our findings, and additional consecutive studies were required.

Morphometric analysis of the medial opticocarotid recess and its anatomical relations relevant to the transsphenoidal endoscopic endonasal approaches

Morphometric analysis of the medial opticocarotid recess

Acta Neurochir (2016) 158:319–324

The medial opticocarotid recess (MOCR) is located in the posterior wall of the sphenoid sinus, medial to the junction of the optic canal (OC) and the carotid prominence (CP). There is controversy in the literature in relation to the presence of the MOCR and its constancy, which is relevant when approaching the skull base through an endoscopic route.

Methods The morphometric relations of the MOCR with the surrounding structures were studied in 18 cadaveric specimens after endoscopic endonasal approach (EEA).

Results The distance between both MOCR was 11.06± 1.14 mm; the distance between the MOCR and the lateral opticocarotid (LOCR) recess was 5.56 ± 0.85 mm; the distance between the MOCR and the suprasellar recess was 3.72±0.49 mm; the angle between the MOCR plane and the OC 13.32±2.30°; the angle between the MOCR plane and the CP 13.50±2.68° and; the angle between the OC and the CP 26.81±4.26°. All measurements showed low variability, with low standard deviation and interquartile range. No relations were found between any of the measurements.

Conclusions The MOCR may be used as a reference point for precise location of structures during EEA. Objective measurements may be especially useful in cases with distorted sphenoid bone anatomy.

Cochlear line: a novel landmark for hearing preservation using the anterior petrosal approach

Cochlear line- a novel landmark for hearing preservation using the anterior petrosal approach

J Neurosurg 123:9–13, 2015

The goal of this study was to develop a practical landmark for the safe and easy identification of the cochlea when performing anterior petrosectomy based on cadaver dissection results.

Methods The cochlear line was defined as the line drawn from the crossing point between the greater superficial petrosal nerve (GSPN) and the petrous internal carotid artery to the line drawn over the apex of the superior circumference of the dura of the internal auditory canal at a right angle. The validity of the cochlear line marking the anteromedial perimeter of the cochlea at the angle of the GSPN and the internal acoustic canal as a practical landmark were evaluated using 5 cadaver heads.

Results The mean distance (± SD) measured from the cochlear line to the margin of the cochlear cavity was 2.25 ± 0.51 mm (range 1.50–3.00 mm).

Conclusions Anterior petrosectomy can be performed more efficiently by using the cochlear line as a key landmark to preserve the cochlea.

Quantitative analysis of the Kawase versus the modified Dolenc-Kawase approach for middle cranial fossa lesions with variable anteroposterior extension

The_Middle_Fossa_Approach_and_Extended_Middle

J Neurosurg 123(1):14-22

The surgical corridor to the upper third of the clivus and ventral brainstem is hindered by critical neurovascular structures, such as the cavernous sinus, petrous apex, and tentorium. The traditional Kawase approach provides a 10 × 5–mm fenestration at the petrous apex of the temporal bone be tween the 5th cranial nerve and internal auditory canal. Due to interindividual variability, sometimes this area proves to be insufficient as a corridor to the posterior cranial fossa. The authors describe a modification to the technique of the extradural anterior petrosectomy consisting of additional transcavernous exploration and medial mobilization of the cisternal component of the trigeminal nerve. This approach is termed the modified Dolenc-Kawase (MDK) approach.

METHODS
The authors describe a volumetric analysis of temporal bones with 3D laser scanning of dry and drilled bones for respective triangles and rhomboid areas, and they compare the difference of exposure with traditional versus modified approaches on cadaver dissection. Twelve dry temporal bones were laser scanned, and mesh-based volumetric analysis was done followed by drilling of the Kawase triangle and MDK rhomboid. Five cadaveric heads were drilled on alternate sides with both approaches for evaluation of the area exposed, surgical freedom, and angle of approach.

RESULTS
The MDK approach provides an approximately 1.5 times larger area and 2.0 times greater volume of bone at the anterior petrous apex compared with the Kawase’s approach. Cadaver dissection objectified the technical feasibility of the MDK approach, providing nearly 1.5–2 times larger fenestration with improved view and angulation to the posterior cranial fossa. Practical application in 6 patients with different lesions proves clinical applicability of the MDK approach.

CONCLUSIONS
The larger fenestration at the petrous apex achieved with the MDK approach provides greater surgical freedom at the Dorello canal, gasserian ganglion, and prepontine area and better anteroposterior angulation than the traditional Kawase approach. Additional anterior clinoidectomy and transcavernous exposure helps in dealing with basilar artery aneurysms.

Keywords: Kawase,Dolenc,petrous,cadaver,quantitative,petrosectomy,skull base

Endoscopic endonasal resection of skull base chondrosarcomas

Endoscopic endonasal resection of skull base chondrosarcomas- technique and early results

J Neurosurg 122:735–742, 2015

The authors of this study sought to report the technique and early clinical outcomes of a purely endonasal endoscopic approach for resection of petroclival chondrosarcomas.

Methods Between 2010 and 2014, 8 patients (4 men and 4 women) underwent endonasal endoscopic operations to resect petroclival chondrosarcomas at 2 institutions. The patients’ mean age was 44.8 years (range 30–64 years). One of the patients had previously undergone radiation therapy and another a staged craniotomy. Using volumetric software, an independent neuroradiologist assessed the extent of the resections on MRI scans taken immediately after surgery and at the 3-month follow-up. Immediate complications and control of symptoms were also recorded. In addition, the authors reviewed the current literature on surgical treatment of chondrosarcoma.

Results The mean preoperative tumor diameter and volume were 3.4 cm and 9.8 cm3, respectively. Six patients presented with cranial neuropathies. Endonasal endoscopic surgery achieved > 95% resection in 5 of the 8 patients and < 95% resection in the remaining 3 patients. One of the 6 neuropathies resolved, and the remaining 5 partially improved. One instance of postoperative CSF leakage required a reoperation for repair; no other complications associated with these operations were observed. All of the patients underwent adjuvant radiotherapy.

Conclusions According to the authors’ experience, the endoscopic endonasal route is a safe and effective approach for the resection of appropriately selected petroclival chondrosarcomas.

An Experimental Feasibility Study on Robotic Endonasal Telesurgery

Robotic teleneurosurgery

Neurosurgery 76:479–484, 2015

Novel robots have recently been developed specifically for endonasal surgery. They can deliver several thin, tentacle-like surgical instruments through a single nostril. Among the many potential advantages of such a robotic system is the prospect of telesurgery over long distances.

OBJECTIVE: To describe a phantom pituitary tumor removal done by a surgeon in Nashville, Tennessee, controlling a robot located approximately 800 km away in Chapel Hill, North Carolina, the first remote telesurgery experiment involving tentacle-like concentric tube manipulators.

METHODS: A phantom pituitary tumor removal experiment was conducted twice, once locally and once remotely, with the robotic system. Robot commands and video were transmitted across the Internet. The latency of the system was evaluated quantitatively in both local and remote cases to determine the effect of the 800-km distance between the surgeon and robot.

RESULTS: We measured a control and video latency of ,100 milliseconds in the remote case. Qualitatively, the surgeon was able to carry out the experiment easily and observed no discernable difference between the remote and local cases.

CONCLUSION: Telesurgery over long distances is feasible with this robotic system. In the longer term, this may enable expert skull base surgeons to help many more patients by performing surgeries remotely over long distances.

Solitary lesions of the clivus: what else besides chordomas?

Clivus lesions

Solitary non-chordomatous lesions of the clivus are rare pathologies, which represent a diagnostic challenge. This study provides an overview of the clinical, radiological and prognostic characteristics of non-chordomatous clival lesions, highlighting current therapeutic options.

Methods Twenty-two non-chordomatous lesions of the clivus were collected. A retrospective analysis of clinical and radiological patterns as well as survival data was conducted.

Results Clinical presentation was a result of local mass effect. Imaging features, although mainly specific, were not always diagnostic. Extent of surgery was gross total in 45.5 % of cases. Depending on the histology, biological behaviour and presence of seeding, adjuvant treatment was performed, tailoring the treatment strategy to the single patient.

Conclusions Solitary non-chordomatous lesions of the clival bone are more prevalent than expected. They should be approached with a correct differential diagnosis, considering specific epidemiological, radiological, and histopathological characteristics, to minimise diagnostic bias and allow the planning of the best treatment strategy.

Extended endoscopic transsphenoidal approach infrachiasmatic corridor

EE transsphenoidal approach infrachiasmatic corridor

Neurosurg Rev (2015) 38:137–147

An extended endoscopic transsphenoidal approach is required for skull base lesions extending to the suprasellar area. Inferior approach using the infrachiasmatic corridor allows access to the lesions through the tumor growth that is favorable for the extended transsphenoidal approaches. Infrachiasmatic corridor is a safer route for the inferior approaches that is made up by basal arachnoid membrane and Liliequist’s membrane with its leaves (diencephalic and mesencephalic leaf). This area extends from the optic canal and tuberculum sella to the corpus mamillare.

We performed extended endoscopic approach using the infrachiasmatic corridor in 52 cases, including tuberculum sella meningiomas (n:23), craniopharyngiomas (n:16), suprasellar Rathke’s cleft cyst (n:6), pituitary adenoma (n:2), fibrous dysplasia (n:1), infundibular granulosa cell tumor (n:2), and epidermoid tumor (n:2). Total resection was achieved in 17 of 23 (74 %) with tuberculum sellae meningioma using infrachiasmatic approach. Twenty patients presented with visual disorders and 14 of them improved. There were two postoperative cerebrospinal fluid (CSF) leakages and one transient diabetes insipidus and one permanent diabetes insipidus. Sixteen patients were operated on by the infrachiasmatic approach for craniopharyngiomas. Improvement was reached in seven of eight patients presented with visual disorders. Complete tumor resection was performed in 10 of 16 cases and cyst aspiration in 4 cases, and there were remnants in two cases. Postoperative CSF leakage was seen in two patients.

Infrachiasmatic corridor provides an easier and safer inferior route for the removal of middle midline skull base lesions in selected cases.

Neurosurgery Department. “La Fe” University Hospital. Valencia, Spain

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