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

Limitations of the endonasal endoscopic approach in treating olfactory groove meningiomas

Acta Neurochir (2017) 159:1875–1885

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.

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.

Preservation of hearing following awake surgery via the retrosigmoid approach for vestibular schwannomas in eight consecutive patients

Acta Neurochir (2017) 159:1579–1585

Hearing preservation in patients with vestibular schwannomas remains difficult by microsurgery or radiosurgery.

Method: In this study, awake surgery via the retrosigmoid approach was performed for vestibular schwannomas (volume, 11.6 ± 11.2 ml; range, 1.3–26.4 ml) in eight consecutive patients with preoperative quartering of pure tone audiometry (PTA) of 53 ± 27 dB.

:Results After surgery, hearing was preserved in seven patients and improved in one patient. The postoperative quartering PTA was 51 ± 21 dB. Serviceable hearing (class A + B + C) using the American Association of Otolaryngology-Head and Neck Surgery (AAO-HNS) classification was preserved in all patients. Preoperative useful hearing (AAO-HNS class A + B) was observed in three patients, and useful hearing was preserved in all three of these patients after surgery. In addition, useful facial nerve function (House-Blackmann Grade 1) was preserved in all patients.

:Conclusions These results suggest that awake surgery for vestibular schwannomas is associated with low patient morbidity, including with respect to hearing and facial nerve function.

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.

Contralateral supraorbital keyhole approach to medial optic nerve

J Neurosurg 126:940–944, 2017

The authors describe the supraorbital keyhole approach to the contralateral medial optic nerve and tract, both in a series of cadaveric dissections and in 2 patients. They also discuss the indications and contraindications for this procedure.

METHODS In 3 cadaver heads, bilateral supraorbital keyhole minicraniotomies were performed to expose the ipsilateral and contralateral optic nerves. The extent of exposure of the medial optic nerve was assessed. In 2 patients, a contralateral supraorbital keyhole approach was used to remove pathology of the contralateral medial optic nerve and tract.

RESULTS The supraorbital keyhole craniotomy provided better exposure of the contralateral superomedial nerve than it did of the same portion of the ipsilateral nerve. In both patients gross-total resections of the pathology was achieved.

CONCLUSIONS The authors demonstrate the suitability of the contralateral supraorbital keyhole approach for lesions involving the superomedial optic nerve.

 

Safety and Efficacy of TachoSil in Patients Undergoing Skull Base Surgery: A Randomized Controlled Trial

Neurosurgery 80:847–853, 2017

Cerebrospinal fluid (CSF) leakage associated with incomplete sealing of the dura mater is a major complication of intradural procedures.

OBJECTIVE: To compare the efficacy and safety of adjunctive TachoSil (Takeda Pharma A/S, Roskilde, Denmark) with current practice for the prevention of postoperative CSF leaks in patients undergoing elective skull base surgery involving dura mater closure.

METHODS: Patients were intraoperatively randomized to TachoSil or current practice immediately before primary dura closure by suturing ± duraplasty. Choice of adjunctive treatment in the current practice group was at the surgeon’s discretion. Primary efficacy endpoint was occurrence of clinically evident verified postoperative CSF leak or clinically evident pseudomeningocele within 7 weeks after surgery or treatment failure (third application of trial treatment or use of other treatment).

RESULTS: A total of 726 patients were randomized to TachoSil (n = 361) or current practice (n = 365). More current practice patients had sutures plus duraplasty for primary dura closure compared with TachoSil (49.6% vs 35.7%) and fewer had sutures only (45.5% vs 63.2%). The primary endpoint of estimated leak rate favored TachoSil with events in 25 (6.9%) patients vs 30 (8.2%) current practice patients; however, this was not statistically significant (odds ratio: 0.82; 95% confidence interval: 0.47, 1.43; P = .485). Both treatments were well tolerated with similar frequency of adverse events.

CONCLUSION: Very low rates of postoperative CSF leaks can be achieved in patients undergoing skull base surgery of various indications. Although the study did not meet its primary endpoint, TachoSil appears to be safe and effective for the prevention of CSF leaks and associated complications.

 

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.

Unilateral endonasal transcribriform approach with septal transposition for olfactory groove meningioma: can olfaction be preserved?

unilateral-endonasal-transcribriform-approach-with-septal-transposition-for-olfactory-groove-meningioma-can-olfaction-be-preserved

Acta Neurochir (2016) 158:1965–1972

Loss of olfaction has been considered inevitable in endoscopic endonasal resection of olfactory groove meningiomas. Olfaction preservation may be feasible through an endonasal unilateral transcribriform approach, with the option for expansion using septal transposition and contralateral preservation of the olfactory apparatus.

Methods An expanded unilateral endonasal transcribriform approach with septal transposition was performed in five cadaver heads. The approach was applied in a surgical case of a 24 × 26-mm olfactory groove meningioma originating from the right cribriform plate with partially intact olfaction.

Results The surgical approach offered adequate exposure to the anterior skull base bilaterally. The nasal/septal mucosa was preserved on the contralateral side. Gross total resection of the meningioma was achieved with the successful preservation of the contralateral olfactory apparatus and preoperative olfaction. Six months later, the left nasal cavity showed no disruption of the mucosal lining and the right side was at the appropriate stage of healing for a harvested nasoseptal flap. One year later, the preoperative olfactory function was intact and favorably viewed by the patient. Objective testing of olfaction showed microsomia.

Conclusions Olfaction preservation may be feasible in the endoscopic endonasal resection of a unilateral olfactory groove meningioma through a unilateral transcribriform approach with septal transposition and preservation of the contralateral olfactory apparatus.

Endoscopic endonasal anatomy of the ophthalmic artery in the optic canal

Endoscopic endonasal anatomy of the ophthalmic artery in the optic canal

Acta Neurochir (2016) 158:1343–1350

The endoscopic endonasal opening of the optic canal has been recently proposed for tumors with medial invasion of this canal, such as tuberculum sellae meningiomas. Injury of the ophthalmic artery represents a dramatic risk during this maneuver. Therefore, the aim of this study was to analyze the endoscopic endonasal anatomy of the precanalicular and canalicular portion of this vessel, discussing its clinical implication.

Methods The course of the ophthalmic artery was analyzed through five endoscopic endonasal dissections, and 40 nonpathological consecutive MRAs were reviewed.

Results The ophthalmic artery arises from the intradural portion of the supraclinoid internal carotid artery, in 93%of cases about 1.9 mm (range: 1–3) posterior to the falciform ligament. At the entrance into the optic canal, the ophthalmic artery is located infero-medially to the optic nerve in 13 % of cases. In 50 % of these cases the artery moves infero-laterally along its course, remaining in a medial position in the others. In cases with an non medial entrance of the ophthalmic artery, it runs infero-lateral to the optic nerve for its entire canalicular portion, with just one exception.

Conclusion The endoscopic endonasal approach gives a direct, extensive and panoramic view of the course of the precanalicular and canalicular portion of the ophthalmic artery. Dedicated high-field neuroimaging studies are of paramount importance in preoperative planning to evaluate the anatomy of the ophthalmic artery, reducing the risk of jeopardizing the vessel, particularly for those uncommon cases with an infero-medial course of the artery.

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.

Identification of cranial nerves around trigeminal schwannomas using diffusion tensor tractography

Identification of cranial nerves around trigeminal schwannomas using diffusion tensor tractography

Acta Neurochir (2016) 158:429–435

There are no large series studies identifying the locations of cranial nerves (CNs) around trigeminal schwannomas (TSs); however, surgically induced cranial neuropathies are commonly observed after surgeries to remove TSs. In this study, we preoperatively identified the location of CNs near TSs using diffusion tensor tractography (DTT).

Methods An observational study of the DTT results and intraoperative findings was performed. We preoperatively completed tractography from images of patients with TSs who received surgical therapy. The result was later validated during tumorectomy.

Results A total of three consecutive patients were involved in this study. The locations of CNs V-VIII in relation to the tumor was clearly revealed in all cases, except for CN VI in case 3.The predicted fiber tracts were in agreement with intraoperative observations.

Conclusions In this study, preoperative DTT accurately predicted the location of the majority of the nerves of interest. This technique can be applied by surgeons to preoperatively visualize nerve arrangements.

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.

Full endoscopic endonasal transsellar-transclival approach: the modularity concept

Full endoscopic endonasal transsellar-transclival approach- the modularity concept

Acta Neurochir (2016) 158:437–439

Endoscopic endonasal approaches (EEAs) constitute a reasonable option for the treatment of lesions that involve the sellar and clival regions.

Methods We describe, step by step, the full EEA expanded to the middle and lower clivus for the treatment of perisellar lesions. Delimiting different modules around the sellar region is useful in establishing the best endoscopic approach for each tumor.

A craniopharyngioma (CP) with clival extension will be used as an illustrative example of the modularity concept of these approaches.

Conclusions Transsellar-transclival EEA allows complete resection of lesions located in the sellar and infrasellar region with a low rate of complications.

Prognostic factors of craniopharyngioma with special reference to autocrine/paracrine signaling: underestimated implication of growth hormone receptor

Prognostic factors of craniopharyngioma with special reference to autocrine-paracrine signaling

Acta Neurochir (2015) 157:1731–1740

Craniopharyngioma is a slow-growing tumor classified as benign, but tight adhesion and significant local infiltration to the vital structures are common. In spite of improvement of modern microsurgery techniques and precise anatomical understanding not few cases of this tumor recur, and long-termtumor control and maintenance of quality of life are sometimes difficult. However, very little is known about the effects of the molecular characters of craniopharyngioma on the prognosis.

Methods Ninety eight cases of craniopharyngioma surgically treated at the Department of Neurosurgery, Tohoku University Hospital and Kohnan Hospital from April 1996 to May 2014, 45 males and 53 females aged from 2 to 80 years (mean, 40.84 years) were retrospectively reviewed, and postoperative outcomes and the possible involvement of the autocrine/ paracrine mechanism were investigated. The patients were followed up at intervals of 6 months to assess tumor recurrence, and clinical outcomes were correlated with the findings of immunohistochemical examinations used growth hormone receptor (GHR) and downstream hormones. The follow-up period ranged from 3 to 209 months.

Results Hormone expression was examined in 88 patients, of which 46 specimens (52.3 %) showed high expression of GHR. The GHR high expression group had a significantly shorter duration of postoperative stable disease compared with the low expression group (logrank test, p=0.007). Simultaneous high expression of growth hormone (GH) and GHR was found in 33 specimens (37.5 %), and the high expression group had a significantly shorter duration of postoperative stable disease compared with the low expression group (logrank test, p=0.011). No other hormones showed statistically significant differences in outcomes.

Conclusions High expression of GHR is associated with shorter duration of postoperative stable disease in patients with craniopharyngioma. If the surgical specimens were craniopharyngiomas with high GHR expression, GH supplementation would be introduced quite prudently.

Utility of dynamic computed tomography angiography in the preoperative evaluation of skull base tumors

Utility of dynamic computed tomography angiography in the preoperative evaluation of skull base tumors

J Neurosurg 123:1–8, 2015

The anatomical complexity of skull base tumors mandates detailed preoperative planning for safe resection. In particular, the location of critical vascular and bony structures can influence the surgical approach. Traditional methods, such as MRI, MR angiography and/or venography (MRA/MRV), CT angiography and/or venography (CTA/CTV), and digital subtraction angiography, each have their limitations. One alternative that combines the benefits of both detailed anatomy compatible with intraoperative image guidance and visualization of the vascular flow is the 320–detector row dynamic volume CTA/CTV. The authors investigated this technique’s impact on the surgical approach used in a series of complex intracranial tumors.

Methods All patients with complex intracranial tumors who had undergone preoperative dynamic CTA/CTV as well as MRI in the period from July 2010 to June 2012 were retrospectively reviewed. Those in whom only routine CTA/CTV sequences had been obtained were excluded. Clinical records, including imaging studies, operative reports, and hospital course, were reviewed. Ease in detecting specific major arterial and venous tributaries using dynamic CTA/CTV was graded for each case. Furthermore, 2 skull base neurosurgeons projected a desired surgical approach for each tumor based on MRI studies, independent of the CTA/CTV sequences. The projected approach was then compared with the ultimately chosen surgical approach to determine whether preoperative awareness of vasculature patterns altered the actual operative approach.

Results Sixty-four patients were eligible for analysis. Dynamic CTA/CTV successfully demonstrated circle of Willis arteries, major draining sinuses, and deep internal venous drainage in all cases examined. The superior petrosal sinus, vein of Labbé, tentorial veins, and middle fossa veins were also identified in a majority of cases, which played an important role in preoperative planning. Visualization of critical vascular—especially venous—anatomy influenced the surgical approach in 39% (25 of 64) of the cases.

Conclusions Dynamic CTA/CTV has been applied to few neurosurgical disease pathologies to date. This noninvasive technology offers insight into vascular flow patterns as well as 3D anatomical relationships and provides thin-cut sequences for intraoperative navigation. The authors propose dynamic CTA as an addition to the preoperative planning for complex skull base tumors.

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.

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

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Blister Aneurysms of the Internal Carotid Artery

Bypass for Complex Basilar Aneurysms

Basilar Invagination and Atlanto-Axial Dislocation Video 1

Indocyanine Green Videoangiography “In Negative” Video 2

Indocyanine Green Videoangiography “In Negative” Video 1

Management of a Recurrent Coiled Giant Posterior Cerebral Artery Aneurysm

Bypass for Complex Basilar Aneurysms

Expanded Endonasal Approach for 2012 MERC

Endoscopic Endonasal Middle Clinoidectomy Video 1

Endoscopic Endonasal Middle Clinoidectomy Video 2

Neurosurgery CNS: Flash Fluorescence for MCA Bypass Video 2

Neurosurgery CNS: Flash Fluorescence for MCA Bypass Video 1

Neurosurgery CNS: Endoscopic Transventricular Lamina Terminalis Fenestration Video 2

Neurosurgery CNS: Endoscopic Transventricular Lamina Terminalis Fenestration Video 1

Neurosurgery CNS: Surgery for Giant PCOM Aneurysms Video 2

Neurosurgery CNS: Surgery for Giant PCOM Aneurysms Video 1

NeurosurgeryCNS: Endovascular-Surgical Approach to Cavernous dAVF

Neurosurgery CNS: Lateral Supraorbital Approach Applied to Anterior Clinoidal Meningiomas Video 4

Neurosurgery CNS: Lateral Supraorbital Approach Applied to Anterior Clinoidal Meningiomas Video 3

Neurosurgery CNS: Lateral Supraorbital Approach Applied to Anterior Clinoidal Meningiomas Video 2

Neurosurgery CNS: Lateral Supraorbital Approach Applied to Anterior Clinoidal Meningiomas Video 1

NeurosurgeryCNS: Surgery of AVMs in Motor Areas

NeurosurgeryCNS: The Fenestrated Yaşargil T-Bar Clip

NeurosurgeryCNS: Cotton-Clipping Technique to Repair Intraoperative Aneurysm Neck Tear Video 3

NeurosurgeryCNS: Cotton-Clipping Technique to Repair Intraoperative Aneurysm Neck Tear Video 2

NeurosurgeryCNS: Cotton-Clipping Technique to Repair Intraoperative Aneurysm Neck Tear Video 1

NeurosurgeryCNS. ‘Double-Stick Tape’ Technique for Offending Vessel Transposition in Microvascular Decompression

NeurosurgeryCNS: Advances in the Treatment and Outcome of Brain Stem Cavernous Malformation Surgery: 300 Patients

3T MRI Integrated Neuro Suite

NeurosurgeryCNS: 3D In Vivo Modeling of Vestibular Schwannomas and Surrounding Cranial Nerves Using DIT

NeurosurgeryCNS: Microsurgery for Previously Coiled Aneurysms: Experience on 81 Patients: Video 7

NeurosurgeryCNS: Microsurgery for Previously Coiled Aneurysms: Experience on 81 Patients: Video 6

NeurosurgeryCNS: Microsurgery for Previously Coiled Aneurysms: Experience on 81 Patients: Video 5

NeurosurgeryCNS: Microsurgery for Previously Coiled Aneurysms: Experience on 81 Patients: Video 4

NeurosurgeryCNS: Microsurgery for Previously Coiled Aneurysms: Experience on 81 Patients: Video 3

NeurosurgeryCNS: Microsurgery for Previously Coiled Aneurysms: Experience on 81 Patients: Video 2

NeurosurgeryCNS: Microsurgery for Previously Coiled Aneurysms: Experience on 81 Patients: Video 1

NeurosurgeryCNS: Corticotomy Closure Avoids Subdural Collections After Hemispherotomy

NeurosurgeryCNS: Operative Nuances of Side-to-Side in Situ PICA-PICA Bypass Procedure

NeurosurgeryCNS. Waterjet Dissection in Neurosurgery: An Update After 208 Procedures: Video 3

NeurosurgeryCNS. Waterjet Dissection in Neurosurgery: An Update After 208 Procedures: Video 2

NeurosurgeryCNS. Waterjet Dissection in Neurosurgery: An Update After 208 Procedures: Video 1

NeurosurgeryCNS: Fusiform Aneurysms of the Anterior Communicating Artery

NeurosurgeryCNS. Initial Clinical Experience with a High Definition Exoscope System for Microneurosurgery

NeurosurgeryCNS: Endoscopic Treatment of Arachnoid Cysts Video 2

NeurosurgeryCNS: Endoscopic Treatment of Arachnoid Cysts Video 1

NeurosurgeryCNS: Typical colloid cyst at the foramen of Monro.

NeurosurgeryCNS: Neuronavigation for Neuroendoscopic Surgery

NeurosurgeryCNS:New Aneurysm Clip System for Particularly Complex Aneurysm Surgery

NeurosurgeryCNS: AICA/PICA Anatomical Variants Penetrating the Subarcuate Fossa Dura

Craniopharyngioma Supra-Orbital Removal

NeurosurgeryCNS: Use of Flexible Hollow-Core CO2 Laser in Microsurgical Resection of CNS Lesions

NeurosurgeryCNS: Ulnar Nerve Decompression

NeurosurgeryCNS: Microvascular decompression for hemifacial spasm

NeurosurgeryCNS: ICG Videoangiography

NeurosurgeryCNS: Inappropiate aneurysm clip applications


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