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Background Surgical approaches to the third ventricle (TV) have always represented a technical challenge in neurosurgery. Virtual reality (VR) is attaining increasing relevance in training programs and preoperative planning. The aim of this study is to demonstrate the worthwhile mutual contribution of VR simulations and specimen dissections to develop a new surgical approach to the TV. Methods The transcortical endoportal subchoroidal endoscope-assisted (TEPSEA) approach was planned and simulated thanks to VR (Surgical Theater©, LLC, Cleveland, Ohio), and then implemented on cadaver specimens by using the VBAS portal system (Viewsite™ Brain Access System TC Model, Vycor Medical™ Inc). We assessed anthropometric measurements during VR planning and evaluated surgical operability during anatomical dissections. Results Surgical field depths measured between 75.6 and 85.3 mm to mammillary bodies and habenular commissure, which were in mean 20.2 mm away. An 18-mm movement was estimated for 15°-posterior tilting of a 70-mm long VBAS. Excellent exposure and maneuverability were achieved within the TV through a 2.47 cm2 portal working area. The 30°-endoscope assistance expanded the access towards the anterior and posterior walls of the TV particularly to the infundibular recess, mammillary bodies, habenular commissure and pineal recess. Conclusions We documented the utility of a step-by-step VR planning and simulation followed by anatomical dissections to study surgical approaches to deep brain areas. The TEPSEA exploits the portal system and endoscopic assistance to access the entire TV minimizing cortical and white matter manipulation.

Background Pathologies of the ventral thoracic spine represent a challenge, igniting arguments about which should be the ideal surgical approach to access this area. Anterior transthoracic thoracotomy and a number of posterolateral routes have been developed. Among the latter, costotransversectomy has demonstrated to provide good ventral exposure with a lower, but not negligible, morbidity. The optimal approach should be the one minimizing surgical morbidity on both neural and extraneural structures while optimizing exposure. Methods The authors described the combined, rib-sparing, bilateral approach (CRBA) to the ventral mid/low-thoracic spine. The technique combines a transfacet pedicle partially sparing approach on one side and a transpedicular with transverse process resection on the contralateral one. A laboratory investigation was conducted. The technique was applied in a surgical setting, and a case was reported. Results CRBA is rib-sparing, completely extracavitary, and does not require pleural exposure and paraspinal muscle splitting, thus minimizing potential morbidity. The combination of 2 corridors ensures the greatest exposure compared with standard posterolateral approaches. The only blind corner is limited to a small area just in front of the dural sac. A bimanual approach optimizes control during surgical manipulation, even if the area of maneuverability and cross-section areas of surgical corridors are slightly limited compared to traditional costotransversectomy due to the minimally invasive nature of the procedure. Conclusions CRBA represents a safe and effective option to access the ventral mid/low thoracic spine. It provides great exposure and bimanual manipulation of the surgical target, minimizes potential morbidity, and avoids entrance into the thoracic cavity and paraspinal muscle splitting.

Surgical anatomy training in a dedicated research laboratory and attendance to focused "hands-on" dissection courses are of high educational importance in order to acquire and maintain surgical expertise in skull base surgery, both for young and more experienced surgeons. Nevertheless, transitioning surgical skills and anatomic knowledge from the laboratory to the operative room it is not free of challenges, especially during skull base approaches where the three-dimensional surgical orientation can be quite complex. We present a "step-by-step" and "side-by-side" surgical anatomy report on a translabyrinthine approach that was practiced in the laboratory then performed in the operative room by the surgical team, and we compare surgical anatomy exposures while discussing intraoperative techniques, nuances and challenges, both in the laboratory and the operative room.

Inadequate temporal muscle (TM) reconstruction after surgery may hesitate in potentially severe functional and aesthetic sequelae, making it of paramount importance to carefully consider TM reconstruction even in case of small deformities.The authors describe the combined temporal muscle augmentation technique (CTMA), an innovative technique for TM augmentation for muscle reconstruction in case of small to medium substance loss.A cadaver study was conducted as preclinical validation of the technique for the assessment of CTMA coverage capability. CTMA consists in a combination of 2 techniques for muscle surface coverage (MSC) increase: the radial (RA) and the longitudinal augmentation (LA), which enables to harvest a radial (RF) and a longitudinal flap (LF), respectively.Each flap derives from a different muscle-bundle, spearing TM segmentation and functional performance, and are supplied by a specific neuro-vascular peduncle, which makes flaps functionally independent.A surgical case is reported to demonstrate the feasibility of the technique.Combined temporal muscle augmentation technique provides an overall coverage surface of 6.5 ± 0.6 cm, which corresponds to a gap distance of 2.5 ± 0.2 cm, with RF providing a statistically significant larger surface of coverage compared to LF (×2.1; P = 0.0001).Combined temporal muscle augmentation technique is easy and fast to perform displaying a good reconstructive capability with complete preservation of temporal muscle anatomic compartmentalization and segmental vasculature. It might be considered as a safe and effective alternative in the reconstruction of small-to medium TM defects.

Background A paramount concern after transmaxillary approaches has been skull base reconstruction. Regional pedicled flaps represent the best reconstructive option. We have described a technique to harvest a lateral-based multilayered vascularized flap for skull base reconstruction after resection of large tumors using the transmaxillary transpterygoid approach (TMTPA). Methods We performed a cadaver study using the TMTPA to harvest the combined temporal galeofascial flap (CTGF). The first layer, with major sealing capabilities, is composed by a temporoparietal galeal-pericranial flap. The second layer is composed by temporal muscle fascia to provide mechanical support for flap dural engrafting. Results The CTGF provides excellent coverage of both the clival dural lining and the ipsilateral pterygopalatine fossa structures (×1.6). The CTGF is pliable and easy to harvest. It offers great flexibility in flap content and design, providing a large quantity of vascularized tissue. The vascular pedicle derives from the superficial temporal vessels, which can ensure flap trophism. Conclusions CTGF represents an effective option as a regional multilayered pedicled flap for skull base reconstruction after resection of clival tumors using the TMTPA. The flap pedicle, owing to its anatomical location, will often be preserved even after repeated microsurgical or endoscopic procedures, providing a technical alternative for reconstruction even in patients who have undergone multiple surgeries with low residual availability of regional flaps.

Purpose: A great concern in performing the extradural subtemporal approach (ESTA) is the evaluation of the actual advantage provided by zygomatic osteotomy (ZO). Complications related to zygomatic dissection have been widely reported in the literature, making it of paramount importance to balance the actual need to perform it, against the risk of maneuver-related morbidity. Authors comparatively analyze the putative advantage provided by ZO in the ESTA in terms of anatomic exposure and surgical operability. Technical limits and potentials are critically revised and discussed. Methods: A comparative microanatomical laboratory investigation was conducted. The operability score (OS) was applied for quantitative analysis of surgical operability. Results: ZO was found to provide a weakly significant improvement in the surgical angle of attack (p value 0.01) (mean increase 3°). Maneuverability arch (MAC) increase related to ZO did not reach statistical significance (p value 0.09) (mean increase 2°). The variations provided by MAC increase on the conizing effect (CE) did not lead to an actual advantage in the real surgical scenario, modifying the vision area (VA) in terms of reduction of central vision area (CA) in favor of an increase of peripheral vision area (PA) only in the most caudal part of the surgical field. Ultimately, ZO did not influence the overall OS, scoring both ESTA-ZO+ and ESTA-ZO− 2 out of 3. Conclusion: In the ESTA, ZO does not provide an actual significant advantage in terms of surgical operability on clival and paraclival areas.

Objective: Although orbital surgery has always represented a challenge for neurosurgeons, keyhole and endoscopic techniques are gradually surging in popularity maximizing functional and esthetic outcomes. This quantitative anatomical study first compared the surgical operability achieved through three endoscopic approaches within the inferior orbit: the endoscopic sublabial transmaxillary (ESTMax), the endoscopic endonasal transethmoidal (EETEth), and the endoscope-assisted lateral orbitotomy (ELO). Methods: Each of these approaches was performed bilaterally on five specimens. We described the ESTMax step-by-step, underlining its advantages and pitfalls in comparison with EETEth and ELO. Then, we assessed surgical measurements and operability in ESTMax, EETEth, and ELO. Results: The ESTMax provided the most favorable operative window (278.9 ± 43.8 mm2; EETEth: 240.8 ± 21.5 mm2, p < 0.001; ELO: 263.1 ± 19.8 mm2, p = 0.006), the broadest surgical field area (415.9 ± 26.4 mm2; EETEth: 386.7 ± 30.1 mm2, p = 0.041; ELO: 305.2 ± 26.3 mm2, p < 0.001), surgical field depths significantly shorter than EETEth (p < 0.001) but similar to ELO, the widest surgical angles of attack (45°–65°; EETEth: 20°–30°, p < 0.001; ELO: 25°–50°, p < 0.001), and the greatest surgical mobility areas (EETEth: p < 0.001; ELO: p < 0.001). Furthermore, the ESTMax allowed multi-angled exposure and handy maneuverability around all the inferior intraorbital targets. Small anterior antrostomy, blunt intraorbital dissections, direct targets’ approach, orbital floor reconstruction, and maxillary bone flap replacement may limit the ESTMax morbidity rates. Conclusions: The ESTMax is a minimally invasive “head-on” orbital approach that exploits endoscopic surgery advantages avoiding the cranio-orbital and trans-nasal approach limitations and possible complications. It represents a promising alternative to EETEth and ELO because of its optimal operability for resecting lesions extending into the entire inferior orbit.

The Myriad is an innovative, high precision tool for tumor resection, designed to work within narrow endoscopic corridors. Due to its application in technically demanding situations, the learning curve associated with its use might be extremely challenging and time-consuming. The authors describe the application of an already validated training model, the skull base injectable tumor model (ITM), to allow trainees to practice with the use of the Myriad during endoscopic skull base procedures. A formalin embalmed cadaveric head was used for technical assessment. Stratathane resin ST-504 derived polymer was injected to mimic skull base tumors and Myriad was used for tumor resection during different endoscopic procedures. An endoscopic endonasal transsphenoidal, a trans-planum trans-tuberculum, and a trans-clival approach have been performed after ITM injection. The Myriad was used for tumor debulking and blunt manipulation, qualitatively evaluating the technical challenges in performing the surgical dissection. Injectable tumor model demonstrates to be a valuable educational tool to train surgeons in the use of Myriad, potentially speeding up the learning curve in the acquirement of necessary technical skills in manipulating the instrument, even in case of demanding surgical situation.

Recent studies have demonstrated diminished cognitive function, worse quality of life, and no overall survival benefit from the addition of adjuvant whole brain radiation therapy (WBRT) to stereotactic radiosurgery (SRS) in the management of brain metastases. This study analyzes the treatment outcome of SRS, specifically CyberKnife Radiosurgery, based on the total tumor volume compared to the absolute number of lesions.A retrospective analysis of hospital records at Virginia Hospital Center for patients with brain metastases who underwent CyberKnife Radiosurgery between June 2008 and June 2014 was performed. Previous treatment history, metastatic tumor dimensions, and outcomes were recorded. Predictors of neurological defects, local tumor progression, and overall survival were assessed with univariate and multivariate analysis.We identified 130 adult patients with a median age of 61.5years and a median follow-up of 7.1months. Unfavorable outcomes such as death, tumor progression, or neurological defect showed correlation with cumulative tumor volume greater than the median volume of 7cc (p0.05). Worsening neurological defects showed an association with an increased number of lesions (p0.02) and age (p0.05). For local tumor progression, patients who have received WBRT were less likely to progress (.74, 95% CI, .48, 1.10), while those who received chemotherapy (1.48 95% CI, .98, 2.26), or surgery (1.56 95%, CI .98, 2.47) without WBRT were more likely to progress.Our data suggest that a cumulative tumor volume greater than 7cc correlates with worse outcomes following CyberKnife Radiosurgery. In addition, WBRT appears to have a role in improved survival for patients with increased tumor burden. A prospective study is warranted to validate these findings.

Clinical neurosurgery has been practiced in the US capital for just over 100 years. As former residents and fellows of Drs. Harvey Cushing and Walter Dandy moved to the region, hospitals at Georgetown and George Washington Universities became early adopters of this new surgical discipline. Later academic neurosurgery programs were established at the National Institutes of Health, Walter Reed Medical Center, and Children's National Medical Center. Neurosurgical pioneers at these institutions developed new technologies and diagnostic procedures which continue to inform our current practice. In addition, continued collaboration between the multiple training sites in Washington, DC has uniquely enriched our residents' training experience.

BACKGROUND: Surgical approaches to the orbit are challenging and require combined multispecialist skills. Considering its increasing relevance in neurosurgical practice, keyhole surgery could be also applied to this field. However, mastering a minimally invasive approach necessitates an extended learning curve. For this reason, virtual reality (VR) can be effectively used for planning and training in this demanding surgical technique. OBJECTIVE: To validate the mini fronto-orbital (mFO) approach to the superomedial orbit, using VR planning and specimen dissections, conjugating the principles of skull base and keyhole neurosurgery. METHODS: Three-dimensional measurements were performed thanks to Surgical Theater (Surgical Theater© LLC), and then, simulated craniotomies were implemented on cadaver specimens. RESULTS: The mFO approach affords optimal exposure and operability in the target area and reduced risks of surrounding normal tissue injuries. The eyebrow skin incision, the minimal soft-tissue retraction, the limited temporalis muscle dissection and the single-piece craniotomy, as planned with VR, are the key elements of this minimally invasive approach. Furthermore, the “window-opening” cotton-tip intraorbital dissection technique, based on widening surgical corridors between neuromuscular bundles, provides a safe orientation and a deep access inside the orbit, thereby significantly limiting the risk of jeopardizing neurovascular structures. CONCLUSION: The mFO approach associated to the window-opening dissection technique can be considered safe, effective, suitable, and convenient for treating lesions located in the superomedial orbital aspect, up to the orbital apex.

Purpose Brain metastases have a highly variable prognosis depending on the primary tumor and associated prognostic factors. Standard of care for patients with these tumors includes craniotomy, stereotactic radiosurgery (SRS), or whole brain radiotherapy (WBRT) for patients with brain metastases. Brachytherapy shows great promise as a therapy for brain metastases, but its role has not been sufficiently explored in the current literature. Material and methods The PubMed, Cochrane, and Scopus databases were searched using a combination of search terms and synonyms for brachytherapy, brain neoplasms, and brain metastases, for articles published between January 1st, 1990 and January 1st, 2018. Of the 596 articles initially identified, 37 met the inclusion criteria, of which 14 were review articles, while the remaining 23 papers with detailing individual studies were fully analyzed. Results Most data focused on 125I and suggested that it offers rates of local control and overall survival comparable to standard of care modalities such as SRS. However, radiation necrosis and regional recurrence were often high with this isotope. Studies using photon radiosurgery modality of brachytherapy have also been completed, resulting superior regional control as compared to SRS, but worse local control and higher rates of radiation necrosis than 125I. More recently, studies using the 131Cs for brachytherapy offered similar local control and survival benefits to 125I, with low rates of radiation necrosis. Conclusions For a variety of reasons including absence of physician expertise in brachytherapy, lack of published data on treatment outcomes, and rates of radiation necrosis, brachytherapy is not presently a part of standard paradigm for brain metastases. However, our review indicates brachytherapy as a modality that offers excellent local control and quality of life, and suggested that its use should be further studied.

Background Intraventricular tumors present difficult challenges to the neurosurgeon. Neurosurgeons have begun to explore the possibilities of using the endoscope in the radical resection of solid intraventricular lesions. There is a steep learning curve when dealing with such lesions with an endoscope. Objective The aim of this study was to create a laboratory training model for neuroendoscopic surgery of intraventricular lesions guided by the navigation system. We believe this technique is more reliable than the traditional approach using contrast injection with C-arm x-ray guidance. Materials and Methods Five formalin-fixated, latex-injected cadaveric heads were used. The arterial system was injected with red latex through the common carotid arteries, and the venous system was injected with blue latex through the internal jugular veins at the C6 vertebral level. The contrast-enhancing tumor polymer, Stratathane resin ST-504-derived polymer (SRSDP), was injected into the lateral ventricle via Frazier's point under direct endoscopic visualization and real-time neuronavigation guidance. When navigation was used for trajectory planning, the peel-away sheath was registered using a frameless navigational system (BrainLAB, Feldkirchen, Germany). A questionnaire was distributed to all participants in an endoscopic cadaveric course in which the models were used to evaluate the endoscopic tumor model. Results Neurosurgeons participating in the course performed an endoscopic approach to resect the intraventricular tumor model through an ipsilateral frontal burr hole. The properties of the SRSDP mixture could be manipulated through varying concentrations of the materials used, in order to reach the desired consistency of a nodular solid lesion and possibility for piecemeal resection. The tumor model allowed participants to compare between normal and pathologic endoscopic anatomy in the same cadaveric head. Conclusion This injectable tumor model with the combination of neuroendoscopy and navigation can improve the accuracy of the endoscopic approach and minimize the risk of cadaveric brain specimen damage that in return augments the feeling of lifelike conditions. Using this endoscopic injectable tumor model technique can assist neurosurgeons' preparation for the challenges associated with an endoscopic piecemeal resection of a solid lesion in the lateral or third ventricle.

Background Surgery of the third ventricle still represents a challenge in modern neurosurgery. To optimize the surgical planning, some aspects, related to ventricular anatomy, have to be taken into consideration. An operability score could represent a preoperative tool to evaluate these variables to choose a tailored surgical approach. Methods We compared the transcallosal transforaminal approach and the combined interhemispheric subcommissural translamina terminalis approach (CISTA) to the anterior part of the third ventricle, applying the operability score. Results Compared with the transcallosal transforaminal approach, the CISTA provides a statistically significant improvement in terms of depth of surgical field, surgical angle of attack, and maneuverability arc considering as 4 approach-related critical structures: the optic chiasm (P value

Background Anterolateral skull base surgery in the sellar and parasellar regions has always represented a technical challenge for neurosurgeons. The microscopic endoscope-assisted transmaxillosphenoidal approach (MEMSA) affords a direct surgical corridor free from critical skull base structures. Here we describe and critically evaluate the use of MEMSA to access the sellar and parasellar areas, in terms of surgical exposure and operability. Methods Six cadaveric heads were examined. A stepwise dissection using MEMSA was performed. Relevant anatomy and surgical technique were critically described and comparatively reviewed. The operability score was applied for quantitative analysis of surgical operability. Results MEMSA provides wide bilateral surgical exposure and vascular control of the sellar, suprasellar, and parasellar regions, achieving the highest operability on the midline and in the parasellar region. The approach can be tailored to the lesion, with the surgical corridor easily widened toward the contralateral pterygopalatine fossa. Anatomic knowledge of maxillary sinus landmarks is key to the use of this approach. Favorable sphenoidal anatomy is the main limiting factor, making MEMSA a surgical alternative to endoscopic endonasal routes in situations where those routes are not feasible, and the approach of choice in selected cases of primarily sellar lesions widely extending contralaterally to the approached maxillary sinus. Conclusions MEMSA is a safe and effective technique that provides access to the sellar, suprasellar, and contralateral parasellar areas via a direct, minimally disruptive surgical corridor. The preservation of nasal anatomy ensures the availability of mucosal flaps for use in further reconstruction. © 2016 Elsevier Inc.

Background Technical advancements in spine surgery have made possible the treatment of increasingly complex pathologies with less morbidity. Time constraints in surgeons' training have made it necessary to develop new training models for spine pathology. Objective To describe the application of a novel compound, Stratathane resin ST-504 derived polymer (SRSDP), that can be injected at different spinal target locations to mimic spinal epidural, subdural extra-axial, and intra-axial pathologies for the use in advanced surgical training. Material and Methods Fresh-frozen thoracolumbar and cervical spine segments of human and sheep cadavers were used to study the model. SRSDP is initially liquid after mixing, allowing it to be injected into target areas where it expands and solidifies, mimicking the entire spectrum of spinal pathologies. Results Different polymer concentrations have been codified to vary adhesiveness, texture, spread capability, deformability, and radiologic visibility. Polymer injection was performed under fluoroscopic guidance through pathology-specific injection sites that avoided compromising the surgical approach for subsequent excision of the artificial lesion. Inflation of a balloon catheter of the desired size was used to displace stiff cadaveric neurovascular structures to mimic pathology-related mass effect. Conclusion The traditional cadaveric training models principally only allow surgeons to practice the surgical approach. The complex spine pathology simulator is a novel educational tool that in a user-friendly, low-cost fashion allows trainees to practice advanced technical skills in the removal of complex spine pathology, potentially shortening some of the aspects of the learning curve of operative skills that may otherwise take many years to acquire. © Georg Thieme Verlag KGStuttgart New York.

Background: Skull-base reconstruction represents a concern after resection of middle fossa (MF) tumors by the extradural subtemporal transzygomatic approach (ESTZ). Regional pedicled flaps appear to be the best option. This study describes a technique for temporal myofascial segmentation to harvest a multilayered vascularized flap for MF reconstruction, which might preserve temporal muscle (TM) function and its blood supply. Methods: The technique to harvest a combined segmented temporal myofascial flap (CSTMF) is described. The flap consists in a temporal fascial (TFF) and a muscle flap (TMF), composed by TM anterior-medial bundle (AMB). Results: CSTMF provides wide coverage of dural lining, through the TFF, and of dead-space, through the TMF. The possibility to tailor TMF according to the need, anatomically preserving the blood supply, enables to significantly increase its volume. Conclusion: CSTMF represents an effective option as regional multilayered pedicled flap for MF reconstruction, potentially preserving TM function and minimizing the cosmetic impact.

OBJECTIVE: Anterior craniovertebral junction (CVJ) surgery has continued to be one of the most debated neurosurgical topics. The transoral approach (TOA) has been considered the choice for this region. However, it has some limitations and a not negligible degree of surgery-related morbidity. With the advent of endoscopy, the endoscopic endonasal approach (EEA) was developed, which minimized morbidity and improved exposure. To the best of our knowledge, despite the extensive reported data, a comparative anatomical study has not been performed and no definitive consensus has been reached on the indications for both approaches. METHODS: We compared the TOA and EEA to the CVJ using the previously described operability score (OS), calculated at 4 different targets: the C1 tubercle (C1), the lowest exposed point of the odontoid process (C2), the basion (BS) and the middle clivus (MC). The higher the OS for the selected targets, the more favorable the approach. RESULTS: The TOA had higher OSs at the MC, C1, and C2 targets, and the EEA showed greater OSs at MC and C1. The TOA and EEA had similar OSs at the BS. These results have shown that the OS is more favorable at C1-C2 using the TOA and the OSs at the MC and BS were similar. CONCLUSIONS: The OS is an effective method to compare surgical approaches. The present study demonstrated the maximal exposure capability of the 2 approaches. The TOA seemed to be superior for lower targets and the EEA for upper targets. Because of the strong variability in the CVJ anatomy and pathological features, we suggest considering the OS as a further tool to better define the best surgical approach.

Background Treatment modalities for degenerative cervical spine disease are widely debated and refined as new surgical techniques are developed. The current case series compares two common cervical spine procedures, anterior cervical discectomy and fusion (ACDF) and minimally invasive posterior keyhole foraminotomy (MIPKF). The decision making process of the two surgical approaches is discussed, and the long term outcomes are presented. Methods A retrospective chart review of surgical patients having either an ACDF or MIPKF with an extensive chart review. Over 570 patient charts were identified and reviewed between 1994 and 2011. After exclusion, a total of 268 patients were identified in the ACDF group, and 112 patients were identified in the MIPKF group. Primary outcome measurement was the need for any reoperation, whether at the same level or adjacent levels due to recurrence of disease or adjacent level disease. Results An average follow-up of 11.8 (± 3.0) years in the ACDF group and 6.4 (± 4.4) years in the MIPKF group was determined over a 17 year period. There was a reoperation rate of 2.6% in the ACDF group and 2.7% in the MIPKF group during the 17 year time period. Conclusion ACDF has been demonstrated to be an effective surgical procedure in treating degenerative spine disease in patients with radiculopathy and/or myelopathy. However, in a population with isolated radiculopathy and radiological imaging confirming an anterolateral disc or osteophyte complex, the MIPKF can provide similar results without the associated risks that accompany an anterior cervical spine fusion.

Objectives Comparative anatomical studies have proved to be invaluable in the evaluation of advantages and drawbacks of single approaches to access established target areas. Approach-related exposed areas do not necessarily represent useful areas when performing surgical manoeuvres. Accordingly the concept of "operability" has recently been introduced as a qualitative assessment of the ability to execute surgical manoeuvres. The authors propose an innovative model for the quantitative assessment of the operability, defined as "operability score" (OS), which can be effectively and easily applied to comparative studies on surgical anatomy. Methods A microanatomical study was conducted on six cadaveric heads. Results Morphometric measurements were collected and operability scores in selected target points of the surgical field were calculated. As illustrative example, the operability score was applied to the extradural subtemporal transzygomatic approach (ESTZ). Conclusion The operability score is effective in grading system of surgical operability, and instruments manipulation capability. It is a useful tool to evaluate, in a single approach, areas that can be exposed, and to quantify how those areas are suitable for surgical manoeuvres. © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights.

Accurately localizing a spine level in the thoracic spine is often not easily achieved with the existing imaging modalities available in the operating room. The coordination of the preoperative imaging pathology with intraoperative imaging is even more difficult in patients with challenging anatomy. Using standard percutaneous techniques, the authors placed a radiopaque embolization coil into the pedicle of interest under biplanar fluoroscopy in 1 patient. Thoracic spine MRI along with scout MRI was then performed to confirm coil marker placement in relation to the actual spine pathology prior to surgical intervention. No complications were observed during placement of the radiopaque marker. Intraoperatively, the marker was immediately and easily visualized, leading to a confident identification of the correct thoracic spinal level. The preoperative placement of a radiopaque marker into the vertebral pedicle of the identified pathological level combined with postplacement MRI verification provides an advantage over previously proposed techniques in the literature.

"Objective: We describe a variant of the interhemispheric translaminaterminalis approach for the resection of large suprasellar craniopharyngiomas. The approach is a translaminaterminalis route performed below and above the anterior communicating artery (ACoA). A cadaveric microanatomic study was conducted to describe the surgical technique. Methods: Four cadaveric specimens fixed with gluteraldehyde and injected with latex were dissected to illustrate the approach. Results: The surgical steps of the approach are reported. The ACoA anatomy was studied. In particular, the surgical route in-between and lateral to the first and second segments of the anterior cerebral artery and the ACoA complex were examined. The approach was adopted in a clinical setting; two illustrative cases regarding the removal of large craniopharyngiomas with suprasellar extension through this route are described. Conclusions: The approach with preservation of the ACoA may represent a possible route to manage large suprasellar lesions. Combination of the unilateral interhemispheric corridor with the subfrontal and the trans-sylvian routes allows for a safe and radical resection of large suprasellar craniopharyngiomas. © 2013 Elsevier Inc. All rights reserved.. . "

Background A frontal sinus infection, following a transsinus skull base procedure, portends potentially life-threatening complications, making surgical revision mandatory in refractory infections. The authors describe the application of the bilateral temporal myofascial flap (BTMF) as a valuable option for frontal sinus reconstruction, when pericranial or galeal-frontalis myofascial flap (GFMF) is no longer available. Methods A microanatomic laboratory cadaver investigation was conducted to obtain anthropometric measurements. Surgical technique is described, and intraoperative images are provided. Results The surgical steps of this technique and the related intraoperative images are reported. One case illustration regarding frontal sinus reconstruction following a postoperative infection, as a complication after a transsinus procedure, is reported. Conclusion The BTMF should be considered as a valuable option for frontal sinus reconstruction after transsinus skull base procedures when GFMF is not available.

Background: The posterior fusiform gyrus lies in a surgically challenging region. Several approaches have been described to access this anatomical area. The paramedian supracerebellar transtentorial (SCTT) approach benefits from minimal disruption of normal neurovascular tissue. The aim of this study was to demonstrate its application to access the posterior fusiform gyrus. Methods: Three brains and six cadaveric heads were examined. A stepwise dissection of the SCTT approach to the posterior fusiform gyrus was performed. Local cortical anatomy was studied. The operability score was applied for comparative analysis on surgical anatomy. Results: The major posterior landmark used to identify the fusiform gyrus with respect to the medial occipitotemporal gyrus was the collateral sulcus, which commonly bifurcated at its caudal extent. Compared with other surgical approaches addressed to access the region, SCTT demonstrated the best operability in terms of maneuverability arc. Favorable tentorial anatomy is the only limiting factor. Conclusions: The supracerebellar transtentorial approach is able to provide access to the posterior fusiform gyrus via a minimally disruptive, anatomic, microsurgical corridor. © 2016, Springer-Verlag Wien.

Background and Study Objective Several surgical approaches have been previously reported for the treatment of olfactory groove meningiomas (OGM). The trans-frontal-sinus subcranial approach (TFSSA) for the removal of large OGMs is described, comparing it with other reported approaches in terms of advantages and drawbacks. Material and Methods The TFSSA was performed on cadaveric specimens to illustrate the surgical technique. Results The surgical steps of the TFSSA and the related anatomical pictures are reported. The approach was adopted in a clinical setting; a case illustration is reported to demonstrate the feasibility of the described approach and to provide intraoperative pictures. Conclusion The TFSSA represents a possible route to treat large OGMs. The subcranial approach provides early devascularization of the tumor, direct tumor access from the base without traction on the frontal lobes, good overview of dissection of the optic nerves and anterior cerebral arteries, and dural reconstruction with pedicled pericranial flap.

Purpose To evaluate the correlation between vagus nerve stimulation (VNS) efficacy and partial seizures originating from different brain regions. Materials and methods The authors retrospectively analyzed the data of 46 subjects with medically intractable epilepsy who had insertion of VNS between April 1999 and July 2005. The clinical outcome was assessed with Engel classification. Subjects were divided into group A (Engel I, II, and III) and group B (Engel IV) for statistical analysis. Group A was referred as a satisfactory outcome. The statistical analysis of the data was assessed whether these parameters such as age, type of seizure, age at insertion of VNS, and lengths of follow-up affect the outcome. Results Nineteen patients (41.3%) had a satisfactory outcome (Engel II, III). The analysis of VNS efficacy demonstrated that 65% of the patients with frontal lobe epilepsy and only 15% of the patients with temporal lobe epilepsy (TLE) had a satisfactory outcome. There was a statistically significant difference between these types of epilepsyand VNS outcomes (Fisher exact test, P = 0.004). Conclusion VNS is more effective in frontal lobe epilepsy than in temporal lobe epilepsy. Further studies are warranted to verify our findings and the correlation between types of epilepsy and VNS outcome.

Object The authors describe a modified Le Fort I maxillotomy with medial and posterior antrectomy and removal of the pterygoid plates, aimed at improving the lateral surgical exposure during open transmaxillary surgery for pathological conditions involving the clivus. A cadaveric microanatomical study was conducted to compare the planimetric exposures allowed by the transmaxillary transpterygoid (TMTP) approach and the standard Le Fort I maxillotomy (STM). Methods Six cadaveric specimens that had been fixed with glutaraldehyde and injected with latex were dissected to obtain morphometric measurements after both TMTP and STM approaches. The anatomical areas exposed by the surgical approaches were calculated using ImageJ 1.37a software. Results As expected, the TMTP approach allowed for a greater surgical exposure, with an incremental area exposed ranging from 4.9 to 7.6 cm2 (mean ± standard deviation 6.4 ± 1.2 cm2, 95% CI 5.4–7.4 cm2). The amount of additional anatomical area visualized, as recorded as a percentage increase after the TMTP approach when compared with the STM approach, ranged from 83 to 109% (mean 99%). Conclusions The lateral surgical exposure allowed by the STM approach is limited by the pterygoid plates. The TMTP approach significantly improves the exposure of the anatomical regions lateral to the clivus, allowing access to the pterygopalatine and medial infratemporal fossae. In comparison with the STM, the TMTP approach allows for a surgical exposure that is nearly double. The authors conclude that the TMTP approach provides a significant improvement in the surgical exposure of the lateral paraclival areas, when compared with the STM approach.

The pterygopalatine fossa (PPF) is a small anatomic region of particular interest in cranial base surgery. Infectious diseases and malignancy may spread through the PPF to contiguous areas as a result of the low resistance offered by the numerous foramina and fissures that surrounds the fossa. We present an anatomic report on the PPF. Twelve sides of six fixed cadaveric heads were dissected through a LeFort I maxillary osteotomy with transantral exposure of the neurovascular content of the PPF. Arterial vascular patterns of the maxillary artery were observed. The pterygopalatine fossa is a deeply located small anatomic region with a rich neurovascular content. The third portion of the maxillary artery in the PPF may demonstrate a variable vascular morphology. A correct understanding and knowledge of the anatomic structures lodged into the PPF, as well as their relationships and functions, remain crucial to minimizing postsurgical morbidity and intraoperative complications.

With advancing technology, the sensitivity of computed tomography (CT) for the detection of traumatic subarachnoid hemorrhage (tSAH) continues to improve. Increased resolution has allowed for the detection of hemorrhage that is limited to one or two images of the CT exam. At our institution, all patients with a SAH require intensive care unit (ICU) admission, regardless of size. It was our hypothesis that patients with small subarachnoid hemorrhage experience favorable outcomes, and may not require the intensive monitoring offered in the ICU. This retrospective study evaluated 62 patients between 2011 and 2014 who presented to our Level I trauma center emergency room for acute traumatic injuries, and found to have subarachnoid hemorrhages on CT examination. The grade of subarachnoid hemorrhage was determined using previously utilized scoring systems, such as the Fisher, Modified Fisher, and Claassen grading systems. Electronic medical records were used to evaluate for medical decline, neurological decline, neurosurgical intervention, and overall hospital course. Admitting co-morbidities were noted, as were the presence of patient intoxication and use of anticoagulants. Patient outcomes were based on discharge summaries upon which the neurological status of the patient was assessed. Each patient was given a score based on the Glasgow outcome scale. The clinical and imaging profile of 62 patients with traumatic SAH were studied. Of the 62 patients, 0 % underwent neurosurgical intervention, 6.5 % had calvarial fractures, 25.8 % had additional intracranial hemorrhages, 27.4 % of the patients had significant co-morbidities, and 1.6 % of the patients expired. Patients with low-grade tSAH spent less time in the ICU, demonstrated neurological and medical stability during hospitalization. None of the patients with low-grade SAH experienced seizure during their admission. In our study, patients with low-grade tSAH demonstrated favorable clinical outcomes. This suggests that patients may not require as aggressive monitoring as is currently provided for those with tSAH.

With advancing technology, the sensitivity of computed tomography (CT) for the detection of subdural hematoma (SDH) continues to improve. In some cases, the finding is limited to one or 2 images of the CT examination. At our institution, all patients with an SDH require intensive care unit (ICU) admission, regardless of size. In this report, we tested the hypothesis that patients with a small traumatic SDH on their presenting CT examination do not require the intensive monitoring offered in the ICU and can instead be managed on a hospital unit with a lower level of monitoring. This is a retrospective study of patients evaluated and treated at a level I trauma center for acute traumatic intracranial hemorrhage between 2011 and 2014. The clinical and imaging profile of 87 patients with traumatic SDH were studied. Patients with small isolated traumatic subdural hemorrhage (tSDH) (

The present study sought a clearer understanding of spatial memory function consequent to temporal lobe resection, and, in particular, of spatial memory function with respect to two- as well as three-dimensional frames of reference. Relative to a group of 15 control participants, a group of 15 epilepsy patients with right temporal resections demonstrated deficits of memory for locations in a two-dimensional display. A group of 13 epilepsy patients with left temporal resections did not demonstrate such deficits. The right and the left resection groups both demonstrated deficits of memory for item-location relationships in a two-dimensional display. The right but not the left resection group demonstrated deficits of memory for item-location relationships in a three-dimensional display. The differing results that were observed for item-location relationships in two- and three-dimensional displays were attributed to differences in the way item information is bound with location information concerning two- and three-dimensional domains.

Object. The goal of this study was to investigate survival and functional outcomes in patients with high-grade intracranial astrocytomas as a function of the location of the lesion in the dominant or nondominant hemisphere (DH and NDH, respectively), and to suggest management strategies for such patients based on these data. Methods. Data were collected from the Glioma Outcomes Project database, a longitudinal database of demographic, clinical, and outcome data for patients with high-grade intracranial gliomas. From the entire database of 788 patients, a subset of all 280 right-handed patients with newly diagnosed, unilateral gliomas involving potentially eloquent cortex was selected as the sample population. Two cohorts were defined based on the location of the tumor in the right or left cerebral hemisphere. All other relevant demographic and clinical data were nearly identical between the cohorts. A Kaplan—Meier analysis was conducted to assess survival, and Karnofsky Performance Scale scores assigned at 6 and 12 months postoperatively were compared as a measure of functional outcome. The analysis demonstrated no difference in survival between patients with lesions in the DH and those with tumors in the NDH. Additionally, no statistically significant difference in functional outcomes was observed between the two groups. Conclusions. Laterality of high-grade gliomas is not an independent prognostic factor for predicting survival or functional outcome. The findings in this study demonstrate that fears of increased postoperative morbidity or mortality in otherwise resectable tumors of the DH are unfounded, and the authors therefore advocate that the surgeon's decision to operate be guided by validated outcome predictors and not biased by tumor lateralization.

Thoracic disc herniation has always carried with it the potential for serious adverse neurological consequences if not treated appropriately. The authors review the historical evolution of treatment for thoracic disc herniation from the early surgical series using dorsal approaches (which were known to involve a significant risk of paraplegia) to later surgical series in which lateral and then ventral approaches to the disc were increasingly emphasized, with significant improvement in patient outcome. The evolution of minimally invasive thoracoscopic techniques is discussed, together with the results of several surgical series demonstrating significant reductions in morbidity compared with more traditional methods. The technique of thoracoscopic discectomy is presented in detail.

Object. Cervical radiculopathy caused by either soft herniated disc material or foraminal stenosis is a common problem. Anterior and posterior surgical approaches are commonly used to decompress the nerve root. The authors undertook a study to establish the feasibility of performing a microendoscopic posterior approach for cervical foraminotomy in the clinical setting. Methods. The authors performed an endoscopic posterior foraminotomy technique in which they used a rigid endoscope, in both a cadaver model and in three clinical cases, including one in which a multiple-level procedure was undertaken. Postoperatively, all patients returned to functional work status within 4 weeks. The mean length of hospitalization was 1.3 days. Conclusions. The advantages to this technique include improved intraoperative visualization, a smaller incision, and significantly less postoperative discomfort compared with a traditional keyhole approach.

Background: Intradural pathology in the region of the cauda equina is uncommon and generally comes to attention secondary to pain or neurologic deficit. A number of surgeons choose to excise these lesions under EMG monitoring of the nerve roots supplying the lower extremity muscles, anal sphincter, and detrusor muscle. In this article, the authors describe a detrusor muscle monitoring technique that has been found to be simple, reliable, and cost-effective in the management of intradural pathology of the cauda equina. Methods: Fourteen consecutive patients with tumors of the cauda equina who underwent surgical management performed using the standard Foley catheter monitoring technique were included in this study and their outcomes analyzed. Results: In 86% of patients, a gross total resection was achieved. Subtotal resections were performed in 2 patients because of involvement of critical nerve roots. In all cases, the nerve roots supplying the detrusor muscle were successfully identified using this technique. No patient suffered a clinically apparent decline in bladder function during the postoperative period. Conclusion: The standard Foley catheter detrusor monitoring technique is a simple, reliable, and cost-effective method to identify and prevent injury to the sacral nerve roots innervating the urinary bladder during intradural exploration of the cauda equina.

The objective of this study was to improve the ability to detect cerebrovascular complications in patients undergoing complicated neurosurgical procedures using on-line monitoring of cerebral pH with in vivo microdialysis. We employed on-line pH monitoring in patients with a variety of neurosurgical procedures including high-flow bypass surgery, aneurysm clipping, and temporal resection in epilepsy treatment. The pH was monitored with a microdialysis probe, usually inserted into the frontal cortex and pH of the dialysate was measured on-line with a pH electrode. We monitored 17 cases: 12 high-flow extracranial-intracranial (EC-IC) bypass procedures, 3 surgeries to clip large basilar tip aneurysms under protection of hypothermic circulatory arrest, and 2 surgeries for intractable seizure disorders. In the patients undergoing high-flow bypass, the pH remained stable in 5 patients and all had an uneventful outcome. In 3 patients, the pH decreased during surgery. One patient had a severe hemiparesis on awaking from anesthesia. The fall in pH in another patient was corrected when the blood pressure was raised during surgery. The pH was also responsive to changes in intraoperative ventilation and probably also to brain edema with elevation of pH values. In the three patients undergoing basilar tip aneurysm clipping under hypothermic circulatory arrest, the pH fell to 6.41 in one patient. This patient awoke with a mild hemiparesis. In the other two patients, the pH was stable during the hypothermia and neither patient had complications. In the patients undergoing temporal lobectomy and hippocampectomy, the pH fell rapidly with the onset of ischemia. We conclude that it is possible to monitor the cerebral extracellular pH with on-line microdialysis. The information obtained may alert the surgeon to the possibility of impending cerebral ischemia or other complications. However, further experience is needed before the technique can be recommended for general use.

Background and Objectives Few simulation models are available that provide neurosurgical trainees with the challenge of distorted skull base anatomy despite increasing importance in the acquisition of safe microsurgical and endoscopic techniques. We have previously reported a unique training model for skull base neurosurgery where a polymer is injected into a cadaveric head where it solidifies to mimic a skull base tumor for resection. This model, however, required injection of the polymer under direct surgical vision via a complicated alternative approach to that being studied, prohibiting its uptake in many neurosurgical laboratories. Conclusion We report our updated skull base tumor model that is contrast-enhanced and may be easily and reliably injected under fluoroscopic guidance. We have identified a map of burr holes and injection corridors available to place tumor at various intracranial sites. Additionally, the updated tumor model allows for the creation of mass effect, and we detail the variation of polymer preparation to mimic different tumor properties. These advancements will increase the practicality of the tumor model and ideally influence neurosurgical standards of training. © Georg Thieme Verlag KG.

The authors describe the extradural subtemporal transzygomatic (ESTZ) approach and its variants to expose the clival and paraclival areas. A microanatomical study was conducted to quantify the clival and paraclival exposure and the maneuverability areas obtained by microscope and endoscope using the ESTZ approach. Section versus preservation of the third trigeminal branch (V3) and petrous apicectomy to obtain a wider clival exposure and a better internal carotid artery control are discussed. Eight cadaveric specimens were dissected to obtain morphometric measurements after performing the ESTZ approach and its variants. Anatomic areas exposed by the approaches were calculated using the ImageJ 1.37a software. The ESTZ approach performed with sectioning of V3 and petrous apicectomy allowed for a mean incremental exposed area of 1.8 cm2 (range, 1.24-2.43 cm2). The mean amount of additional anatomic areas visualized after the ESTZ approach with petrous apicectomy if compared with the ESTZ approach without petrous apicectomy was 24% (range, 14.4%-37.5%). The mean percentage increase of maneuverability area after petrous apicectomy was 69.9% (range, 43.8%-96.6%). The ESTZ approach is suitable when dealing with extradural tumors of the middle-upper clivus extending into the ipsilateral paraclival area. V3 section and petrous apicectomy increase the operability, the surgical exposure, and the maneuverability area and improve vascular control on the internal carotid artery. Application of endoscopy does not impact on the maneuverability area but enhances the visualization of blind corners; endoscopic surgical view without drilling the petrous apex is comparable to that obtained by the microscope after petrous apicectomy.

Objective: To analyze long-term results and to determine prognostic factors on seizure outcome in a series of patients with temporal lobe epilepsy (TLE) who underwent anteromedial temporal lobectomy (AMTL). Materials and methods: From 1995 to 1998 forty-two patients suffering from non-lesional TLE underwent tailored AMTL at our Institution. We retrospectively reviewed surgical results and calculated predictive factors of good outcome in the long term. Results: Sixty-four percent of patients were rendered seizure free (median follow up 60 months). Eleven cases (26.2%) had a significant reduction of disabling epileptic episodes. Poor seizure control was observed in four patients (9.5%). Overall surgical morbidity was 4.7%. Medial temporal sclerosis (MTS) was the most common histopathological finding (69% of cases). The presence of unilateral hippocampal abnormalities on qualitative MRI was significantly associated with excellent postoperative outcome (p < 0.011). Qualitative preoperative MRI had a positive predictive value of 83% in detecting both MTS at pathological examination and excellent outcome. Conclusions: Tailored AMTL is a safe and effective procedure in the treatment of selected patients with medically refractory TLE. Data from preoperative qualitative MRI well correlated with histopathological findings. The presence of unilateral hippocampal atrophy on qualitative MRI was predictive of excellent outcome in the long-term follow up.

Transitional cell carcinoma (TCC) of the ureter is an uncommon urologic malignancy, with approximately 150 cases diagnosed annually. Metastatic brain disease from ureteral TCC is exceedingly rare. To our knowledge, our case report represents only the second report of brain metastasis from ureteral TCC and the only reported patient to undergo resection of their TCC brain metastasis.

BACKGROUND Knowing the location of the venous sinuses in the combined lateral posterior fossa and lateral cranial base approach is important to prevent their inadvertent injury. The identification of surface landmarks related to these structures is useful in planning such surgical approaches. METHODS Twelve injected adult cadaver specimens and 10 dried skulls were used to study the relationship of the venous sinuses to various surface anatomic structures. RESULTS The asterion was not clearly seen in 60% of the studied cadaver sides. The asterion was always clearly seen in the dry skull preparations. The upper margin of the superior nuchal line was found to range from 1.5 mm to 14 mm inferior to the lower margin of the lateral transverse sinus. In 85% of our specimens, the mastoid groove was found to completely overlie the sigmoid sinus. CONCLUSIONS The asterion was found to be variable in its anatomic relations to other identifiable structures. This variability in relation to other posterior fossa bony landmarks limits its overall usefulness as a consistently stable marker for intracranial structures. The first and most superolateral burr hole for lateral posterior fossa procedures can be safely placed 1 cm below the superior nuchal line and 1 cm medial to the top of the mastoid groove. A burr hole in this location will avoid the transverse and sigmoid sinuses, as well as the transverse-sigmoid junction, yet will be high enough and lateral enough to provide easy exposure of these venous sinuses for all lateral posterior fossa procedures.

Object. The aim of this study was to describe six variations of the extreme-lateral craniocervical approach, their application, and treatment results. Methods. During a 4-year period 69 patients underwent surgery in which six variations of the extreme-lateral craniocervical approach were performed. The variations included: the transfacetal approach (TFA), performed to treat four lesions in the upper cervical spine anterior or anterolateral to the spinal cord; the retrocondylar approach, to treat five intradural lesions located anterolateral to the medulla oblongata and six vascular lesions to expose the extradural segment of the vertebral artery (VA); the partial transcondylar approach (PTCA), to treat 18 intradural lesions located anterior to the medulla oblongata; the complete transcondylar approach (CTCA), to treat 13 extradural lesions that involved the lower clivus and anterior upper cervical spine; the extreme-lateral transjugular approach, to treat 14 jugular foramen tumors; and the transtubercular approach with or without division of the sigmoid sinus, to treat complex VA and vertebrobasilar junction aneurysms. An anatomical prosection was performed to study the surgical exposure of each of the six variations of the extreme-lateral craniocervical approach. Total removal was achieved in 35 (69%) of the patients with tumor; subtotal resection was achieved in 16 (31%) of those patients. In the 12 patients with VA aneurysms, seven underwent clipping, three underwent trapping and a vein graft bypass procedure, and two underwent trapping without the use of a bypass procedure. In five other patients, different cystic, inflammatory, and other vascular lesions were successfully treated. Fifty percent of the patients who underwent surgery via the TFA, 83% via the of the CTCA, and 11% via the PTCA required an occipitocervical fusion procedure. The mean Karnofsky Performance Scale score was 74.7 preoperatively and 76.4 postoperatively. Major complications were hydrocephalus (nine patients), cerebrospinal fluid leakage (seven patients), worsened cranial nerve function (seven patients), vertebrobasilar vasospasm (one patient), and sigmoid sinus thrombosis (one patient). Conclusions. To treat lesions in the region of the foramen magnum and surrounding areas, the approach should be tailored to each specific lesion to provide the needed exposure without unnecessary operative steps.