Temporal lobe injury with middle fossa approach to intracanalicular vestibular schwannomas: a systematic review

There are several surgical approaches for vestibular schwannoma (VS) resection. However, management has gradually shifted from microsurgical resection, toward surveillance and radiosurgery. One of the arguments against microsurgery via the middle fossa approach (MFA) is the risk of temporal lobe retraction injury or sequelae. Here, we sought to evaluate the incidence of temporal lobe retraction injury or sequela from a MFA via a systematic review of the existing literature. This systematic review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Relevant studies reporting temporal lobe injury or sequela during MFA for VS were identified. Data was aggregated and subsequently analyzed to evaluate the incidence of temporal lobe injury. 22 studies were included for statistical analysis, encompassing 1522 patients that underwent VS resection via MFA. The overall rate of temporal lobe sequelae from this approach was 0.7%. The rate of CSF leak was 5.9%. The rate of wound infection was 0.6%. Meningitis occurred in 1.6% of patients. With the MFA, 92% of patients had good facial outcomes, and 54.9% had hearing preservation. Our series and literature review support that temporal lobe retraction injury or sequelae is an infrequent complication from an MFA for intracanalicular VS resection.

A Nod for Meckel: A Novel Surgical Position Utilizing Meckel's Cave Anatomy for Percutaneous Glycerol Rhizotomy in Trigeminal Neuralgia

Objective  We aim to describe a novel positioning technique using a specific surgical table to achieve the optimal angle during percutaneous glycerol rhizotomy (PGR) for trigeminal neuralgia (TN). Design  This is a descriptive and photographic analysis of successful cases for future implementation. Setting  This study was conducted at a single-institution, academic center. Participants  The participants were adult patients with TN who underwent PGR and provided consent for publication. Main Outcome Measures  Primary outcomes of this study were TN symptomatic relief and surgical complications. Results  The use of a beach chair sliding headboard surgical table for PGR is plausible and ensures precise and immobile head flexion for 1 hour postglycerol injection. There were no intraoperative or postoperative complications. All patients achieved successful reduction of TN symptoms. Conclusions  Utilizing this new method of intraoperative navigation with a unique surgical table in the upright position, surgeons may achieve precise head adjustments post-PGR. Head flexion has been postulated as a means of ensuring glycerol containment in Meckel's cave. This method can help standardize this procedure for future systematic studies on the importance of head positioning post-PGR.

Significant tumor compression of the middle cerebellar peduncle is associated with worse facial nerve outcomes and lower extent of resection in surgery for medium-sized vestibular schwannomas - A radiographic analysis of a case series

BACKGROUND AND OBJECTIVE

Optimizing the extent of resection (EOR) and facial nerve outcomes (FNO) remain a challenge in medium to large vestibular schwannomas (VS). Currently, tumor size has been the only consistently reported factor predicting FNO and EOR. Here, we sought to evaluate whether the degree of the tumor's compression on the middle cerebellar peduncle (PC) influences FNO and EOR in medium to large VS.

METHODS

This retrospective case series included 99 patients who underwent surgical resection of their VSs from 2014 to 2022. Preoperative MR imaging was used to measure the degree of PC. Patient medical records were queried to determine the EOR and FNO.

RESULTS

Patients with unfavorable FNO (HB 3 +) immediately post-op had significantly greater PC than those with favorable FNO (19.9 vs. 15.4 mm, P = .047). This significance was not observed at the last follow-up but there was a trend. When medium-sized tumors (15-30 mm) were analyzed separately, patients with unfavorable FNO immediate post-op and at last follow-up had significantly greater PC than their favorable counterparts (14.1 vs 8.7 mm). Significantly greater PC was also observed in patients who underwent subtotal resection (20.7 mm) compared to near (14.3 mm) and gross total resection (10.8 mm). Multivariate analyses confirmed these findings in medium-sized tumors, but not large-sized tumors.

CONCLUSION

The degree of PC as measured on preoperative imaging can predict FNO and EOR in medium-sized vestibular schwannomas. Medium-sized tumors with > 15 mm of PC likely will have worse FNO and lower EOR.

Nasofrontal meningiomas: retrospective series and review of literature

INTRODUCTION

Lesions affecting the anterior skull base and involving the paranasal sinuses (PNS), nasal cavity (NC), and orbit are infrequent and include predominantly a wide variety of sinonasal malignancies. Less than 3% of intracranial meningiomas extend extracranially and involve PNS and NC. Given their relatively low incidence, little is known about the treatment outcome of this subset of meningiomas.

METHODS

Systematic literature and retrospective review of own institutional series of midline anterior skull base meningiomas with significant PNS and NC involvement were performed.

RESULTS

Overall, 21 patients-16 in the literature review group and 5 of our institutional series-were included. Eleven (52.4%) patients had had a prior surgery for midline anterior skull base meningioma. Of patients having reported WHO grade, two were WHO II. Gross total resection was achieved in 16 (76.2%) of patients, utilizing solely transcranial approach in 15 patients, combined endoscopic and transcranial in five patients and purely endoscopic in one patient. Postoperative radiotherapy was administered in three (14.3%) patients, all after total resection via transcranial route, without a history of prior treatment. A postoperative cerebrospinal fluid leak was reported in four (10%) patients, requiring surgical repair in two. There were no reports of postoperative meningitis. No neurological complications were observed except of a reported worsening of vision in one patient.

CONCLUSION

Midline anterior skull base meningiomas infrequently extend significantly into the PNS and NC. Despite their significant involvement, along with concomitant involvement of orbit, gross total resection is possible in the majority of cases with low morbidity using either purely transcranial or combined endoscopic/transcranial approach.

Outcomes of Arterial Bypass for Posterior Circulation Atherosclerosis: A Case Series

BACKGROUND

Extracranial-intracranial bypass is an effective treatment option for moyamoya disease and in well-selected cases of anterior circulation intracranial atherosclerotic disease; however, the effectiveness of bypass is less evident in posterior circulation atherosclerosis. Updated surgical techniques and clinical guidelines necessitate modern appraisal of arterial bypass for symptomatic patients with posterior circulation atherosclerotic disease who are refractory to medical management.

OBJECTIVE

To evaluate the complications, graft patency, and postoperative outcomes of arterial bypass for posterior circulation intracranial atherosclerotic disease.

METHODS

Perioperative records of consecutive bypass patients were retrospectively evaluated to determine the clinical course and surgical outcomes.

RESULTS

Arterial bypass was performed in 8 cases with a median age of 62 years. All 8 patients underwent direct bypass with an autologous occipital artery donor vessel. Recipient vessel selection varied on a case-by-case basis, with the superior cerebellar artery used in 4 cases, the posterior inferior cerebellar artery in 3 cases, and the anterior inferior cerebellar artery in 1 case. There were no significant intraoperative or postoperative complications. Postoperatively, all 8 patients displayed clinical improvement of their preoperative symptoms, with a significant decrease of 2.5 points on the modified Rankin Scale (P < .001). Postoperative imaging confirmed full graft patency in 7 patients and partial patency in 1 patient.

CONCLUSION

Excellent postoperative outcomes and no major complications after posterior circulation arterial bypass for intracranial atherosclerotic disease highlight the utility of this intervention for the treatment of medically refractory or symptomatic posterior circulation intracranial atherosclerotic disease. Larger studies may be valuable to validate these findings.

Postoperative magnetic resonance imaging signal changes in middle cerebral peduncle after vestibular schwannoma surgery

BACKGROUND AND PURPOSE

Preoperative compression of middle cerebellar peduncle (MCP) is often observed in vestibular schwannomas. Its re-expansion is expected after tumour resection, however, frequently its thickness remains unchanged or undergoes further atrophy. Similarly, increased MCP FLAIR signal is often observed and thought to be associated with intraoperative MCP injury. This study investigates the dynamics of MCP FLAIR signal changes over time and their implications in long-term MCP atrophy.

MATERIALS AND METHODS

Retrospective analysis of patients operated between 2011 and 2019 was performed. Measurements of FLAIR signals and MCP thickness were performed preoperatively, postoperatively and at follow-up.

RESULTS

28 patients (15 females, mean age 51.94 years) were included. The mean follow-up was 23.98 months. The mean tumour size was 2.99 cm. The MCP FLAIR signal was elevated preoperatively in 10 (35.7%) patients and further increased postoperatively in 22 (78.6%), followed by its decrease at follow up (7 patients, 25%). An immediate postoperative re-expansion of middle cerebellar peduncle was observed in 24 (85.7%) patients. No association between tumour size and preoperative FLAIR was established, however tumour size was negatively associated with the MCP thickness. A significant negative association between a postoperative FLAIR and follow-up thickness (p < 0.001) was noted, even if controlling for tumour size and both tumour size and preoperative MCP thickness.

CONCLUSION

In patients with vestibular schwannomas undergoing surgical resection, the middle cerebellar peduncle FLAIR signal seems to associated with long term thickness of MCP, regardless of its initial size, however does not seem to correlate with the clinical outcome.

The Final Cut: Evolution of Cavernous Sinus Decompression Beyond the Dolenc Cut

BACKGROUND

Meningiomas involving the cavernous sinus (CS) represent a formidable challenge to neurosurgeons. Because of high morbidity, aggressive tumor resection within the CS has been largely replaced by extracavernous tumor resection and decompression of the CS. The widely used Dolenc method involves blind dural transection over the oculomotor nerve, potentially placing the crossing trochlear nerve at risk.

OBJECTIVE

To provide a safer way for the decompression of the CS and at the same time, circumferential resection of the temporal lobe dura.

METHODS

Cadaveric dissection of 8 cadaveric heads (16 sides) was performed. Frontotemporal craniotomy with zygomatic osteotomy was performed. Extradural and intradural dissection of the lateral wall of the CS and free edge of tentorium was performed. Photographic documentation, artistic illustrations, and illustrative video cases are provided.

RESULTS

Three tether points were released: anterior-the meningo-orbital band, lateral-dura over the V2 and V3, and medial-superficial layer of the free edge of tentorium. Transection of the superficial layer of the free edge of the tentorium along its edge, in conjunction with a lateral cut over the temporal convexity, constitutes the final cut, allowing a resection of the lateral CS wall and the circumferential resection of temporal lobe dura.

CONCLUSION

Using the "final cut" technique allows for a circumferential resection of the temporal lobe dura and lateral CS wall while avoiding blind cuts that could put cranial nerves at risk. All dural transections are performed in anatomically separated layers under constant visualization.

Changing Enhancement Pattern and Tumor Volume of Vestibular Schwannomas After Subtotal Resection

BACKGROUND

Surgical strategy in vestibular schwannomas may require subtotal resection to preserve neurologic function. Residual tumor growth pattern and contrast enhancement in the immediate postresection period remain uncertain. We sought to evaluate changes in the enhancement pattern and volume of vestibular schwannomas after subtotal resection in the immediate postoperative period.

METHODS

Volumetric analysis of tumor size and enhancement patterns of vestibular schwannomas were measured on magnetic resonance imaging (MRI) scans obtained within 3 days of surgery, 3 months after surgery, and 1 year after surgery.

RESULTS

Nineteen patients were eligible for inclusion in the study (9 male and 10 female) with an average age of 47 years. Contrast enhancement was absent in 6 of 19 (32%) of cases on the immediate postresection MRI with return of expected enhancement on subsequent studies. Volumetric analysis identified that tumors decreased in size by an average of 35% in the first 3 months (P = 0.025) after resection and 46% in the first year after resection (P < 0.01).

CONCLUSIONS

Vestibular schwannomas that undergo subtotal resection tend to decrease in size over the first 3 months after resection. Residual tumor volume may fail to enhance on the immediate postresection MRI. Both of these findings could lead surgeons to misinterpret degree of resection after surgery and have implications for clinical decision making and research reporting in the scientific literature for vestibular schwannomas after subtotal resection.

Teflon versus Ivalon in Microvascular Decompression for Trigeminal Neuralgia: A 2-Center 10-Year Comparison

BACKGROUND

Trigeminal neuralgia features jolts of pain along the distribution of the trigeminal nerve. If patients fail conservative management, microvascular decompression (MVD) is typically the next step in treatment. MVD consists of implanting a separating material, often Teflon, between the nerve and compressive lesions. A review found similar success and complication rates between Teflon and Ivalon, another commonly used material. The aim of this study was to analyze outcomes and complications associated with Teflon and Ivalon in MVD.

METHODS

We conducted a 2-center retrospective cohort study of trigeminal neuralgia treated with MVD between 2005 and 2019. Patients with no postoperative follow-up were excluded. Postoperative pain was graded using the Barrow Neurological Institute (BNI) pain intensity score. Relapse was defined as a BNI score of 4-5 during follow-up after initial pain improvement or an initial BNI score of 1-3.

RESULTS

The study included 221 MVD procedures in 219 patients. Ivalon was implanted in 121 procedures, and Teflon was implanted in 100 procedures. Multivariate analysis found that implant type had no effect on final BNI score (P = 0.305). Relapse rates were similar at 5- and 10-year follow-up (5-year: Ivalon 10.7%, Teflon 18.0%, P = 0.112; 10-year: Ivalon 11.6%, Teflon 19.0%, P = 0.123). There was no difference in postoperative immediate facial numbness (P = 0.125). Postoperative hearing difficulty was higher in the Ivalon cohort (8.4% vs. 1.0%; P = 0.016).

CONCLUSIONS

We found no significant difference in final BNI score or risk of relapse between Ivalon and Teflon. Complications were similar, although Ivalon was more associated with temporary postoperative hearing loss.

The Return Back to Typical Practice from the "Battle Plan" of the Coronavirus Disease 2019 (COVID-19) Pandemic: A Comparative Study

BACKGROUND

Every aspect of the medical field has been heavily affected by the coronavirus disease 2019 (COVID-19) pandemic, and neurosurgical services are no exception. Several departments have reported their experiences and protocols to provide insights for others impacted. The goals of this study are to report the load and variety of neurosurgical cases and clinic visits after discontinuing the COVID-19 Battle Plan at an academic tertiary care referral center to provide insights for other departments going through the same transition.

METHODS

The clinical data of all patients who underwent a neurosurgical intervention between May 4, 2020, and June 4, 2020 were obtained from a prospectively maintained database. Data of the control group were retrospectively collected from the medical records to compare the types of surgeries/interventions and clinic visits performed by the same neurosurgical service before the COVID-19 pandemic started.

RESULTS

One hundred sixty-one patients underwent neurosurgical interventions, and seven-hundred one patients were seen in clinic appointments, in the 4-week period following easing back from our COVID-19 "Battle Plan." Discontinuing the "Battle Plan" resulted in increases in case load to above-average practice after a week but a continued decrease in clinic appointments throughout the 4 weeks compared with average practice.

CONCLUSIONS

As policy-shaping crises like pandemics abate, easing back to "typical" practice can be completed effectively by appropriately allocating resources. This can be accomplished by anticipating increases in neurosurgical volume, specifically in the functional/epilepsy and brain tumor subspecialties, as well as continued decreases in neurosurgical clinic volume, specifically in elective spine.

Value of the Petromeatal Angle in Predicting Outcome of Translabyrinthine Resection of Vestibular Schwannomas

BACKGROUND

Factors associated with extent of tumor resection (EOR) and facial nerve outcomes include tumor size, anterior extension of the tumor, patient age, and surgical approach.

OBJECTIVE

To check whether preoperative measurement of the petromeatal (PMA), petroclival (PCA), and petrous-petrous (PPA) angles can help in predicting EOR, facial nerve outcome, and cerebrospinal fluid (CSF) leak occurrence in patients undergoing vestibular schwannoma (VS) surgery via the translabyrinthine approach (TLA).

METHODS

A total of 75 patients were included in this retrospective study. Preoperative magnetic resonance imaging constructive interface in steady state and postcontrast T1-weighted sequences through the internal acoustic meatus were used to measure the PMA, PCA, and PPA.

RESULTS

There was a statistically significant association between tumor size and EOR; every additional cm in tumor size decreases the odds of gross-total (GTR)/near-total (NTR) resection by 524% (P = .0000355).After controlling for tumor size, the logistic models revealed a significant effect of the angles on EOR. For example, in a patient with a 2-cm VS, every additional degree in PMA, PCA, and PPA increases the odds of GTR/NTR by 2.3% (P = .0000571), 4.05% (P = .0000397), and 0.37% (P = .0000438), respectively.After adjusting for tumor size, sex, and age, the effect of PMA on the occurrence of an immediate postoperative facial nerve deficit and CSF leak indicated a trend towards significance (P = .0581 and P = .0568, respectively).

CONCLUSION

More obtuse petrous bone angles, namely PMA, PCA, and PPA, are good predictors of GTR or NTR in patients undergoing VS surgery via TLA and may be associated with better facial nerve outcomes and lower CSF leak occurrences.

Impact of the COVID-19 Pandemic on Neurosurgical Practice at an Academic Tertiary Referral Center: A Comparative Study

BACKGROUND

Neurosurgical services have been affected by the 2019 novel coronavirus disease (COVID-19) pandemic, and several departments have reported their experiences and responses to the COVID-19 crisis in an attempt to provide insights from which other impacted departments can benefit. The goals of this study were to report the load and variety of emergent/urgent neurosurgical cases after implementing the "Battle Plan" at an academic tertiary referral center during the COVID-19 pandemic and to compare these variables with previous practice at the same institution.

METHODS

The clinical data of all patients who underwent a neurosurgical intervention between March 23, 2020, and April 20, 2020, were obtained from a prospectively maintained database. Data of the control group were retrospectively collected from the medical records to compare the types of surgeries/interventions performed by the same neurosurgical service before the COVID-19 pandemic started.

RESULTS

Over a 4-week period during the COVID-19 pandemic, 91 patients underwent emergent, urgent, and essential neurosurgical interventions. Patient screening at teleclinics identified 11 urgent surgical cases. The implementation of the Battle Plan led to a significant decrease in the caseload, and the variation of cases by subspecialty was evident when compared with a control group comprising 214 patients.

CONCLUSIONS

Delivery of optimal care and safe practice and education at an academic neurosurgical department can be well maintained with proper execution of crisis protocols. Teleclinics proved to be efficient in screening patients for urgent neurosurgical conditions, but in-person clinic visits may still be necessary for some cases in the immediate postoperative period.

Human stem cells transplanted into the rat stroke brain migrate to the spleen via lymphatic and inflammation pathways

Despite mounting evidence of a massive peripheral inflammatory response accompanying stroke, the ability of intracerebrally transplanted cells to migrate to the periphery and sequester systemic inflammation remains unexamined. Here, we tested the hypothesis that human bone marrow mesenchymal stromal cells intracerebrally transplanted in the brain of adult rats subjected to experimental stroke can migrate to the spleen, a vital organ that confers peripheral inflammation after stroke. Sham or experimental stroke was induced in adult Sprague-Dawley rats by a 1 hour middle cerebral artery occlusion model. One hour after surgery, rats were intracerebrally injected with human bone marrow mesenchymal stromal cells (3×10⁵/9 μL), then euthanized on day 1, 3, or 7 for immunohistochemical assays. Cell migration assays were performed for human bone marrow mesenchymal stromal cells using Boyden chambers with the bottom plate consisting of microglia, lymphatic endothelial cells, or both, and treated with different doses of tumor necrosis factor-α. Plates were processed in a fluorescence reader at different time points. Immunofluorescence microscopy on different days after the stroke revealed that stem cells engrafted in the stroke brain but, interestingly, homed to the spleen via lymphatic vessels, and were propelled by inflammatory signals. Experiments using human bone marrow mesenchymal stromal cells co-cultured with lymphatic endothelial cells or microglia, and treated with tumor necrosis factor-α, further indicated the key roles of the lymphatic system and inflammation in directing stem cell migration. This study is the first to demonstrate brain-to-periphery migration of stem cells, advancing the novel concept of harnessing the lymphatic system in mobilizing stem cells to sequester peripheral inflammation as a brain repair strategy.

Indications and Safety of the Zygomatic Osteotomy in Middle Cranial Fossa Surgery: A Retrospective Cohort Review

Background  Zygomatic osteotomy, an adjunct to middle cranial fossa (MCF) surgical approaches, improves the superior-inferior angle of approach and minimizes temporal lobe retraction. However, a decision-making algorithm for selective use of the zygomatic osteotomy and the impact of the zygomatic osteotomy on surgical complications have not been well documented. Objective  We described an algorithm for deciding whether to use a zygomatic osteotomy in MCF surgery and evaluated complications associated with a zygomatic osteotomy. Methods  A retrospective review of MCF cases over 11 years at our academic tertiary referral center was conducted. Demographic variables, tumor characteristics, surgical details, and postoperative complications were extracted. Results  Of the 87 patients included, 15 (17%) received a zygomatic osteotomy. Surgical trajectory oriented from anterior to posterior (A-P) was significantly correlated with the use of the zygomatic osteotomy. Among the cases approached from A-P, we found (receiver-operating characteristic curve) that the cut-off tumor size that predicted a zygomatic osteotomy was 30 mm. Of the 87 cases included, 15 patients had a complication. The multivariate logistic regression model failed to reveal any significant correlation between complications and zygomatic osteotomies. Conclusions  We found that the most important factor determining the use of a zygomatic osteotomy was anticipated trajectory. A-P approaches were most highly correlated with zygomatic osteotomy. Within those cases, a lesion size cut-off of 30 mm was the secondary predicting factor of zygomatic osteotomy use. The odds of suffering a surgical complication were not significantly increased by use of zygomatic osteotomy.

The working road map in a neurosurgical Hybrid Angio-Surgical suite------ development and practice of a neurosurgical Hybrid Angio-Surgical suite

Background

The concept of a Hybrid Angio-Surgical Suite (HASS) has emerged as a solution to the complexity of cerebrovascular surgery and the need for immediate intraoperative feedback. When to use it, what cases are suitable for its use, who can use it and how to use it remain debatable.

Objective

Provide the information regarding the application of the HASS for hospital, neurosurgeon and interventionalist.

Methods

We review the literatures of case reports and studies on the use of the hybrid angio-sugical suite along with application of HASS in our own practice.

Results

Indications for using HASS on different types of cerebral vascular disease, including cerebral aneurysm, AVM, DAVF, carotid and vertebral stenosis/occlusion, are addressed. The application of HASS for other non-cerebral vascular diseases, such as trauma, spine and skullbase cases, is reviewed and discussed.

Conclusion

HASS has made many surgical procedures safer and many difficult or previously untreatable conditions much more tractable and cost-effective. Other than used in cerebral vascular disease, HASS has much more applications, such as trauma, spine and other neurosurgical diseases.

Endoscopic endonasal resection of a medullary cavernoma: a novel case

Brainstem cavernomas can present very challenging operative problems. Endoscopic endonasal approaches to these lesions in the mesencephalon and pons have been described. In this article the authors present the first case of a medullary cavernoma resected by an endoscopic transclival approach. A 26 year-old woman with a 1.5 cm medullary cavernoma presented with imbalance, swallowing difficulty, and right hemibody weakness. She was taken to the operating room for endoscopic endonasal transclival resection. Her pre-existing neurologic deficits worsened initially after surgery, but at three-month follow-up she had made a full neurologic recovery.

Anterior Extension of Tumor is as Important as Tumor Size to Facial Nerve Outcome and Extent of Resection for Vestibular Schwannomas

Objectives  We examined vestibular schwannoma tumor dimension and direction of growth to determine whether these correlate with facial nerve outcome as well as extent of resection (EOR). Design  Retrospective review of prospectively maintained databases. Participants  206 patients were a part of this study. Main Outcome Measures  Tumor dimensions were measured using preoperative magnetic resonance imaging, and a series of ratios were then calculated to further characterize tumor dimension. Regression analyses were performed to investigate correlation with facial nerve outcome and EOR. Results  Patients with tumor extending >1.5 cm anterior to the internal auditory canal (IAC) (AB measurement) were three times more likely to have postoperative House-Brackman grades of 3 or worse. We also found that an EB/BF ratio (representing elongated growth parallel to the IAC axis) ≥1.1 was associated with half the risk of poor facial nerve outcome. Tumors with anterior-posterior diameter (AC measurement) >1.9 cm were five times less likely to undergo gross total resection (GTR). Furthermore, an increased degree of tumor extension into the IAC (DE measurement >2.4 cm) or an increased amount of brainstem compression (EB measurement >1.1 cm) were each associated with a nearly 3-fold decrease in the likelihood of GTR. Conclusion  Our study demonstrates that anterior extent of the tumor is as important as tumor size to facial nerve outcome and degree of resection for vestibular schwannomas.

Paraclival or Cavernous Internal Carotid Artery: One Segment but Two Names

BACKGROUND

The anatomy of the carotid artery has traditionally been understood into segments that correspond to the surrounding relevant anatomy. Transcranial surgery favors the seven segments classification initially posited by our group in 1996. With the advent of endoscopic approaches a new term has been added to the carotid anatomy lexicon "the paraclival internal carotid artery (ICA)." This "paraclival" carotid is a very familiar segment for all endoscopically trained skull base surgeons but a clear correlate to the transcranial anatomy has not been described. The purpose of our study is to improve the communication between endoscopic and open trained skull base surgeons by correlating the endoscopic paraclival ICA to the transcranial segments of the ICA.

METHODS

Two cadaveric specimens underwent both endoscopic and transcranial dissection. Aneurysm clips were placed in the proximal and the distal extent of the paraclival ICA as described in previous literature. The clip positions were visualized and correlated to open anatomical landmarks.

RESULTS

The proximal clip was located just medial to the origin of the petrolingual ligament, while the distal clip was placed just inferior to the posterior genu of the cavernous ICA.

CONCLUSION

The paraclival ICA corresponds to lacerum segment of ICA and vertical cavernous ICA.

"Inverted Gull Wing" Dural Closure and Middle Fossa Floor Reconstruction After Transzygomatic Infratemporal Fossa Approach

BACKGROUND

Ineffective closure of complex skull base approaches leads to wound complications and cerebrospinal fluid (CSF) leak. This can result in protracted hospital stays, additional procedures, delayed postoperative recovery, and increased cost of care. Removal of large middle fossa-infratemporal fossa tumors are particularly problematic as they result in a large dead space with gravity-facilitated CSF leakage into the cavity. In this report we describe the use of a novel technique, the "inverted gull wing" titanium mesh reconstruction.

METHODS

Attempts to address this problem have focused primarily on closure and the use of myocutaneous flaps. Patients who have had multiple prior treatments are often afflicted with significant tissue attenuation that preclude dural closure or the use of local flaps. Although vascularized free flaps are an effective option in this scenario, they can add significant operative time and often yield suboptimal cosmetic results. We describe the use of the inverted gull wing titanium mesh reconstruction in the closure of 2 patients who underwent complex transzygomatic infratemporal fossa approaches for tumor with dural and sinonasal transgression.

RESULTS

Postoperatively, there were no pseudomeningoceles, CSF leaks, or technique-related morbidities.

CONCLUSIONS

The inverted gull wing technique represents a simple, fast, and effective closure for complex transzygomatic infratemporal fossa approaches.

The Subtemporal Approach to Retroinfundibular Craniopharyngiomas: A New Look at an Old Approach

BACKGROUND

Retrochiasmatic, retroinfundibular craniopharyngiomas are surgically challenging tumors. Anterolateral, posterolateral, and endoscopic endonasal approaches represent the most commonly used techniques to access these tumors, but all require an extensive exposure time, and each has its own risks and limitations. The subtemporal approach is a well-known neurosurgical approach that is rarely described for craniopharyngiomas.

OBJECTIVE

To assess the feasibility, advantages, and disadvantages of a subtemporal approach for craniopharyngiomas.

METHODS

Five patients with retrochiasmatic craniopharyngiomas where the majority of the tumor extended behind the dorsal clival line underwent a subtemporal approach for resection. Extent of resection, degree of temporal lobe injury, visual and endocrine outcomes, and time to recurrence were analyzed.

RESULTS

Average tumor volume was 6.4 cm3. Near-total resection was achieved in 80% (4/5) and subtotal in 20% (1/5). All patients had stable or improved vision. There was 1 new permanent endocrine deficiency. Minimal temporal lobe edema was observed in 80% (4/5) of patients. Three patients required postoperative radiation.

CONCLUSION

The subtemporal approach represents a feasible approach for retrochiasmatic, retroinfundibular craniopharyngiomas when gross total resection is not mandatory. It provides rapid access to the tumor and a caudal-to-cranial visualization that promotes minimal manipulation of critical neurovascular structures, particularly the optic apparatus.

Bone marrow-derived stem cell therapy for metastatic brain cancers

We propose that stem cell therapy may be a potent treatment for metastatic melanoma in the brain. Here we discuss the key role of a leaky blood-brain barrier (BBB) that accompanies the development of brain metastases. We review the need to characterize the immunological and inflammatory responses associated with tumor-derived BBB damage in order to reveal the contribution of this brain pathological alteration to the formation and growth of brain metastatic cancers. Next, we discuss the potential repair of the BBB and attenuation of brain metastasis through transplantation of bone marrow-derived mesenchymal stem cells with the endothelial progenitor cell phenotype. In particular, we review the need for evaluation of the efficacy of stem cell therapy in repairing a disrupted BBB in an effort to reduce neuroinflammation, eventually attenuating brain metastatic cancers. The demonstration of BBB repair through augmented angiogenesis and vasculogenesis will be critical to establishing the potential of stem cell therapy for the treatment/prevention of metastatic brain tumors. The overarching hypothesis we advanced here is that BBB breakdown is closely associated with brain metastatic cancers of melanoma, exacerbating the inflammatory response of the brain during metastasis, and ultimately worsening the outcome of metastatic brain cancers. Abrogating this leaky BBB-mediated inflammation via stem cell therapy represents a paradigm-shifting approach to treating brain cancer. This review article discusses the pros and cons of cell therapy for melanoma brain metastases.

Surgical clipping of a basilar perforator artery aneurysm: a case of avoiding perforator sacrifice

BACKGROUND

Aneurysms arising from basilar perforator arteries are very rare. A primary goal of surgery is always preservation of perforator flow. However, in most surgically managed cases in the literature, sacrifice of the perforator was reported. It is important for the literature to demonstrate that patency of the perforator is an achievable goal.

OBJECTIVE

To present the second reported case of perforator flow preservation in the surgical management of basilar perforator artery aneurysms.

CLINICAL PRESENTATION

A 45-year-old woman presented with World Federation of Neurologic Surgeons grade 1 subarachnoid hemorrhage. Digital subtraction angiography ultimately revealed a 2-mm aneurysm of the basilar artery arising from a perforator after an initially negative angiogram. Clipping was performed with perforator patency confirmed on direct inspection and intraoperative angiography. The patient's postoperative course was uneventful, and postoperative magnetic resonance imaging (MRI) showed no evidence of brainstem stroke.

CONCLUSION

Although patency of the perforator is a rather obvious goal of cerebrovascular surgery, the current literature does not reflect an ability to do so in the case of basilar perforator aneurysms. We present only the second reported case of maintenance of perforator flow after clipping of a basilar perforator artery aneurysm.

Surgical Management of Trigeminal Neuralgia

BACKGROUND:

Trigeminal neuralgia is a relatively common neurosurgical pathology with multiple management options. Microvascular decompression (MVD) is nonablative and is considered the gold standard. However, stereotaxic radiosurgery (SRS) and percutaneous stereotaxic rhizotomy (PSR) are 2 noninvasive but ablative options that have rapidly gained support.

OBJECTIVE:

To use Medicare claims data in conjunction with a literature review to assess the usage, effectiveness, and cost-effectiveness of the 3 different invasive treatments for trigeminal neuralgia.

METHODS:

All of the claims of trigeminal neuralgia treatment were extracted from the 2011 5% Inpatient and Outpatient Limited Data Set. Current Procedural Terminology, 4th Edition/International Classification of Diseases, Ninth Revision codes for the 3 different surgical treatment modalities were used to further classify these claims. Kaplan-Meier survival curves in key articles were used to calculate quality-adjusted life years and cost-effectiveness for each procedure.

RESULTS:

A total of 1582 claims of trigeminal neuralgia were collected. Ninety-four (6%) patients underwent surgical intervention. Forty-eight (51.1%) surgical patients underwent MVD, 39 (41.5%) underwent SRS, and 7 (7.4%) underwent PSR. The average weighted costs for MVD, SRS, and PSR were $;40 434.95, $;38 062.27, and $;3910.64, respectively. The quality-adjusted life years were 8.2 for MVD, 4.9 for SRS, and 6.5 for PSR. The cost per quality-adjusted life year was calculated as $;4931.1, $;7767.8, and $;601.64 for MVD, SRS, and PSR, respectively.

CONCLUSION:

This study shows that the most frequently used surgical management of trigeminal neuralgia is MVD, followed closely by SRS. PSR, despite being the most cost-effective, is by far the least utilized treatment modality.

Pediatric intracranial aneurysms: current national trends in patient management and treatment

PURPOSE

Pediatric intracranial aneurysms constitute a medical disease process with many unique features that present unique challenges in orchestrating their treatment. Conflicts exist in pediatric aneurysm literature as to whether endovascular therapy is equivalent to surgical therapy in assuring durable aneurysm obliteration in this population.

MATERIALS AND METHODS

The national Healthcare Cost and Utilization Project (HCUP) Kid's Inpatient Dataset was queried using the HCUPnet system. Overall trends in length of stay (LOS), associated charges, and in-hospital deaths were analyzed for both subarachnoid hemorrhage (SAH) and nonruptured aneurysms from 2000 to 2009. Trends in the type of procedure, associated LOS, and charges were analyzed for SAH from 2003 to 2009. A p value <0.05 was considered statistically significant.

RESULTS

Mean LOS for SAH patients was an additional 7-10 days compared to patients discharged with nonruptured aneurysms. Costs of surgery showed a slight increase, while endovascular procedures also rose 50 % from 2006 to 2009. Interestingly, mean length of stay increased for endovascular procedures from 16.5 to 17.2 days and decreased for surgical procedures from 20.4 to 14.7 days (p < 0.001).

CONCLUSIONS

First, in-hospital mortality and hospital length of stay for pediatric subarachnoid hemorrhage have not significantly declined since 1997. Second, in-hospital charges for the management of both ruptured and nonruptured aneurysms rose by over 200 % from 2000 to 2009. Surgical procedures saw a 6 % increase in price, while endovascular procedures sharply rose in costs by 50 %. Finally, endovascular therapy has increased in utilization, while the frequency of surgical therapy has not changed significantly since 2003.

Stroke in the eye of the beholder

The pathophysiological changes that occur during ischemic stroke can have a profound effect on the surrounding nerve tissue. To this end, we advance the hypothesis that retinal damage can occur as a consequence of ischemic stroke in animal models. We discuss the preclinical evidence over the last 3 decades supporting this hypothesis of retinal damage following ischemic stroke. In our evaluation of the hypothesis, we highlight the animal models providing evidence of pathological and mechanistic link between ischemic stroke and retinal damage. That retinal damage is closely associated with ischemic stroke, yet remains neglected in stroke treatment regimen, provides the impetus for recognizing the treatment of retinal damage as a critical component of stroke therapy.

Cerebral aneurysm as an exacerbating factor in stroke pathology and a therapeutic target for neuroprotection

Stroke remains a major cause of death in the US and around the world. Despite major scientific advances in our understanding of stroke pathology, the only FDA-approved drug for ischemic stroke is tissue plasminogen activator (tPA). Moreover, the therapeutic window for tPA is confined to the acute phase of stroke, thereby greatly limiting its benefits to less than 3% of ischemic stroke patients. Many treatment strategies for stroke have targeted the subacute or chronic phase in an effort to abrogate the secondary cell death that ensues after the initial stroke insult. Here, we advance the hypothesis that blood vessel disruption, or aneurysm, in the brain is an exacerbating factor for stroke, especially in the evolution of the penumbra or peri-infarct area. A better understanding of aneurysm, specifically its dynamic onset and juxtaposition to the ischemic brain tissue should facilitate the development of novel strategies for attenuating the secondary cell death associated with stroke. To this end, we discuss the laboratory and clinical evidence implicating aneurysm formation in stroke and also provide insights on how stem cell therapy may prove efficacious in combating aneurysm and stroke.

Nestin overexpression precedes caspase-3 upregulation in rats exposed to controlled cortical impact traumatic brain injury

Our understanding of biological mechanisms and treatment options for traumatic brain injury (TBI) is limited. Here, we employed quantitative real-time PCR (QRT-PCR) and immunohistochemical analyses to determine the dynamic expression of cell proliferation and apoptosis in an effort to provide insights into the therapeutic window for developing regenerative strategies for TBI. For this purpose, young adult Sprague-Dawley rats were subjected to experimental TBI using a controlled cortical impactor, then euthanized 1-48 hours after TBI for QRT-PCR and immunohistochemistry. QRT-PCR revealed that brains from TBI exposed rats initially displayed nestin mRNA expression that modestly increased as early as 1-hour post-TBI, then significantly peaked at 8 hours, but thereafter reverted to pre-TBI levels. On the other hand, caspase-3 mRNA expression was slightly elevated at 8 hours post-TBI, which did not become significantly upregulated until 48 hours. Immunofluorescent microscopy revealed a significant surge in nestin immunoreactive cells in the cortex, corpus callosum, and subventricular zone at 24 hours post-TBI, whereas a significant increase in the number of active caspase-3 immunoreactive cells was only found in the cortex and not until 48 hours. These results suggest that the injured brain attempts to repair itself via cell proliferation immediately after TBI, but that this endogenous regenerative mechanism is not sufficient to abrogate the secondary apoptotic cell death. Treatment strategies designed to amplify cell proliferation and to prevent apoptosis are likely to exert maximal benefits when initiated at the acute phase of TBI.

Immediate, but not delayed, microsurgical skull reconstruction exacerbates brain damage in experimental traumatic brain injury model

Moderate to severe traumatic brain injury (TBI) often results in malformations to the skull. Aesthetic surgical maneuvers may offer normalized skull structure, but inconsistent surgical closure of the skull area accompanies TBI. We examined whether wound closure by replacement of skull flap and bone wax would allow aesthetic reconstruction of the TBI-induced skull damage without causing any detrimental effects to the cortical tissue. Adult male Sprague-Dawley rats were subjected to TBI using the controlled cortical impact (CCI) injury model. Immediately after the TBI surgery, animals were randomly assigned to skull flap replacement with or without bone wax or no bone reconstruction, then were euthanized at five days post-TBI for pathological analyses. The skull reconstruction provided normalized gross bone architecture, but 2,3,5-triphenyltetrazolium chloride and hematoxylin and eosin staining results revealed larger cortical damage in these animals compared to those that underwent no surgical maneuver at all. Brain swelling accompanied TBI, especially the severe model, that could have relieved the intracranial pressure in those animals with no skull reconstruction. In contrast, the immediate skull reconstruction produced an upregulation of the edema marker aquaporin-4 staining, which likely prevented the therapeutic benefits of brain swelling and resulted in larger cortical infarcts. Interestingly, TBI animals introduced to a delay in skull reconstruction (i.e., 2 days post-TBI) showed significantly reduced edema and infarcts compared to those exposed to immediate skull reconstruction. That immediate, but not delayed, skull reconstruction may exacerbate TBI-induced cortical tissue damage warrants a careful consideration of aesthetic repair of the skull in TBI.

Cyclosporine-A as a neuroprotective agent against stroke: its translation from laboratory research to clinical application

Stoke remains a leading cause of death and disability with limited treatment options. Extensive research has been aimed at studying cell death events that accompany stroke and how to use these same cell death pathways as potential therapeutic targets for treating the disease. The mitochondrial permeability transition pore (MPTP) has been implicated as a major factor associated with stroke-induced neuronal cell death. MPTP activation and increased permeability has been shown to contribute to the events that lead to cell death. Cyclosporine A (CsA), a widely used immunosuppressant in transplantation and rheumatic medicine, has been recently shown to possess neuroprotective properties through its ability to block the MPTP, which in turn inhibits neuronal damage. This newfound CsA-mediated neuroprotection pathway prompted research on its use to prevent cell death in stroke and other neurological conditions. Preclinical studies are being conducted in hopes of establishing the safety and efficacy guidelines for CsA use in human trials as a potential neuroprotective agent against stroke. In this review, we provide an overview of the current laboratory and clinical status of CsA neuroprotection.

A Review of Laboratory and Clinical Data Supporting the Safety and Efficacy of Cyclosporin A in Traumatic Brain Injury

For decades, cyclosporin A (CsA) has proved to be safe and effective for use in transplantation. In the past 10 years, this agent has shown neuroprotective effects in animal models of traumatic brain injury (TBI). This review article provides a critical overview of the literature on CsA neuroprotective effects in animal studies and current findings of clinical trials in the treatment of TBI with an emphasis on the possible CsA molecular mechanism of action. Animal data provide compelling evidence of the therapeutic benefits of CsA in TBI, but the outcome indices are heterogeneous with respect to the animal model of TBI as well as the route, dose, and timing of CsA administration. Similarly, clinical studies (phase II trials) adapting almost identical patient inclusion criteria have demonstrated the safety of CsA use in TBI, but the clinical trials are also heterogeneous based on study design, especially with regard to the variable timing of CsA administration after TBI. In view of the translational shortcomings of the preclinical studies and the rather pilot nature of the limited clinical trials that recently reached phase III, we offer guidance on the future directions of laboratory investigations on CsA that could improve the safety and efficacy of this agent in subsequent larger clinical trials.

Interfascial technique for vertebral artery exposure in the suboccipital triangle: the road map

BACKGROUND

The extradural portion of the vertebral artery (VA-V3) has a unique anatomy at the craniovertebral junction. The exposure of V3 can be accompanied by profuse bleeding from the venous plexus in addition to the potential risk of inadvertent injury of the VA during surgery at the craniovertebral junction. The natural tissue planes represent a road map to the safe exposure of the VA in the suboccipital triangle.

OBJECTIVE

To describe the microsurgical anatomy of the tissue planes in the suboccipital region.

METHODS

The suboccipital region was bilaterally dissected in 6 fresh silicone-injected cadaver heads. An interfascial technique was used to expose the VA-V3 following a tissue plane between the deep suboccipital muscular fascia dorsally and posterior atlantooccipital membrane, the C1 periosteal membrane, and the membrane covering the VA and venous plexus ventrally. The craniovertebral junction was harvested from 2 heads and prepared for histological sections. The same technique was applied in 25 operative cases.

RESULTS

The anatomic dissections confirmed the existence of an interfascial plane that can be dissected in a blunt fashion to reach as far lateral as the transverse processes of C1 and C2. Application of the dissection technique did not require diathermy coagulation in the operating room. In 25 cases, there was no injury of the VA or bleeding from the venous plexus.

CONCLUSION

Vertebral artery exposure in the suboccipital triangle (V3) can be achieved safely with minimal blood loss using a technique that follows the natural tissue plane between the deep suboccipital muscle fascia, the posterior atlantooccipital membrane, the membrane covering VA/venous plexus, and the periosteum of the C1 and C2 laminae.

Insertion of Intracranial Pressure Monitors in Fulminant Hepatic Failure Patients

BACKGROUND

Cerebral edema contributes to the high morbidity and mortality of fulminant hepatic failure (FHF).

OBJECTIVE

We report the results of our early experience with insertion of intraparenchymal intracranial pressure (ICP) monitors in these highly coagulopathic patients.

METHODS

Eleven consecutive patients with FHF met the criteria for invasive ICP monitoring. Recombinant activated factor VII (rFVIIa) was administered at an average dose of 3 mg intravenous bolus (average, 36.7 μg/kg). We inserted the intraparenchymal ICP monitor within 15 minutes to 2 hours after rFVIIa administration, without waiting for the repeat coagulation results. Postprocedure computed tomographic scans of the brain were obtained in all patients.

RESULTS

No hemorrhagic complications were detected on the immediate postprocedure computed tomographic scans. There were no thrombotic complications in this group of patients.

CONCLUSION

In this group of patients with FHF, placement of an ICP monitor without hemorrhagic or thrombotic complications was feasible after administration of rFVIIa. This is a report of our early experience, and caution is advised. Further collaborative randomized studies are needed to prove the efficacy, optimal dosing, and cost effectiveness of rFVIIa for the placement of ICP monitors in this group of patients.

Graft selection in cerebral revascularization

Cerebral revascularization constitutes an important treatment modality in the management of complex aneurysms, carotid occlusion, tumor, and moyamoya disease. Graft selection is a critical step in the planning of revascularization surgery, and depends on an understanding of graft and regional hemodynamics, accessibility, and patency rates. The goal of this review is to highlight some of these properties.

Surgical management of moyamoya disease

Moyamoya disease (MMD) is a progressive, occlusive disease of the distal internal carotid arteries associated with secondary stenosis of the circle of Willis. Symptoms include ischemic infarcts in children and hemorrhages in adults. Bypass of the stenotic vessel(s) is the primary surgical treatment modality for MMD. Superficial temporal artery-to-middle cerebral artery bypass is the most common direct bypass method. Indirect techniques rely on the approximation of vascularized tissue to the cerebral cortex to promote neoangiogenesis. This tissue may be in the form of muscle, pericranium, dura, or even omentum. This review highlights the surgical options available for the treatment of MMD.