Association of 5-aminolevulinic acid fluorescence guided resection with photodynamic therapy in recurrent glioblastoma: a matched cohort study

PURPOSE

Glioblastoma is a malignant and aggressive brain tumour that, although there have been improvements in the first line treatment, there is still no consensus regarding the best standard of care (SOC) upon its inevitable recurrence. There are novel adjuvant therapies that aim to improve local disease control. Nowadays, the association of intraoperative photodynamic therapy (PDT) immediately after a 5-aminolevulinic acid (5-ALA) fluorescence-guided resection (FGR) in malignant gliomas surgery has emerged as a potential and feasible strategy to increase the extent of safe resection and destroy residual tumour in the surgical cavity borders, respectively.

OBJECTIVES

To assess the survival rates and safety of the association of intraoperative PDT with 5-ALA FGR, in comparison with a 5-ALA FGR alone, in patients with recurrent glioblastoma.

METHODS

This article describes a matched-pair cohort study with two groups of patients submitted to 5-ALA FGR for recurrent glioblastoma. Group 1 was a prospective series of 11 consecutive cases submitted to 5-ALA FGR plus intraoperative PDT; group 2 was a historical series of 11 consecutive cases submitted to 5-ALA FGR alone. Age, sex, Karnofsky performance scale (KPS), 5-ALA post-resection status, T1-contrast-enhanced extent of resection (EOR), previous and post pathology, IDH (Isocitrate dehydrogenase), Ki67, previous and post treatment, brain magnetic resonance imaging (MRI) controls and surgical complications were documented.

RESULTS

The Mantel-Cox test showed a significant difference between the survival rates (p = 0.008) of both groups. 4 postoperative complications occurred (36.6%) in each group. As of the last follow-up (January 2024), 7/11 patients in group 1, and 0/11 patients in group 2 were still alive. 6- and 12-months post-treatment, a survival proportion of 71,59% and 57,27% is expected in group 1, versus 45,45% and 9,09% in group 2, respectively. 6 months post-treatment, a progression free survival (PFS) of 61,36% and 18,18% is expected in group 1 and group 2, respectively.

CONCLUSION

The association of PDT immediately after 5-ALA FGR for recurrent malignant glioma seems to be associated with better survival without additional or severe morbidity. Despite the need for larger, randomized series, the proposed treatment is a feasible and safe addition to the reoperation.

Pharmaceutical equivalent 5-aminolevulinic acid fluorescence guided resection of central nervous system tumors: feasibility, safeness and cost-benefit considerations

PURPOSE

5-aminolevulinic acid (5-ALA) fluorescence-guided resection (FGR) has been an essential tool in the 'standard of care' of malignant gliomas. Over the last two decades, its indications have been extended to other neoplasms, such as metastases and meningiomas. However, its availability and cost-benefit still pose a challenge for widespread use. The present article reports a retrospective series of 707 cases of central nervous system (CNS) tumors submitted to FGR with pharmacological equivalent 5-ALA and discusses financial implications, feasibility and safeness.

METHODS

From December 2015 to February 2024, a retrospective single institution series of 707 cases of 5-ALA FGR were analyzed. Age, gender, 5-ALA dosage, intraoperative fluorescence finding, diagnosis and adverse effects were recorded. Financial impact in the surgical treatment cost were also reported.

RESULTS

there was an additional cost estimated in $300 dollars for each case, increasing from 2,37 to 3,28% of the total hospitalization cost. There were 19 (2,69%) cases of asymptomatic photosensitive reaction and 2 (0,28%) cases of photosensitive reaction requiring symptomatic treatment. 1 (0,14%) patient had a cutaneous rash sustained for up to 10 days. No other complications related to the method were evident. In 3 (0,42%) cases of patients with intracranial hypertension, there was vomiting after administration.

CONCLUSION

FGR with pharmacological equivalent 5-ALA can be considered safe and efficient and incorporates a small increase in hospital expenses. It constitutes a reliable solution in avoiding prohibitive costs worldwide, especially in countries where commercial 5-ALA is unavailable.

Intracanalicular vestibular schwannomas: facial and hearing outcomes according to the location of the tumor in relation to the nerves of the internal auditory canal

OBJECTIVE

The objective was to evaluate whether the position of the nerves within the internal auditory canal (IAC) has any effect on preoperative and postoperative cochlear and facial nerve function in patients with intracanalicular vestibular schwannoma (VS) resected through the retrosigmoid transmeatal approach.

METHODS

Forty-four patients with sporadic intracanalicular VS, from a series of 710 patients with VS who underwent operations from January 1993 to April 2022, were retrospectively reviewed. The pattern of displacement of the cranial nerves and tumor within the IAC was recorded. Tumors were divided into 2 types: type T1A lesions had only anteriorly displaced nerves, and type T1B had posteriorly displaced vestibular nerves and anteriorly displaced facial and cochlear nerves. Differences in surgical outcomes between groups in terms of facial nerve function and hearing preservation were evaluated.

RESULTS

Thirty-five cases (79.5%) were T1A tumors and 9 were T1B (20.5%). Gross-total resection and anatomical preservation of the facial and cochlear nerves were achieved in all patients. Postoperatively, all patients with T1A VS maintained normal facial nerve function; however, among T1B VS patients, 6 (67%) retained House-Brackmann grade I, 2 worsened to grade II, and 1 worsened to grade III at 6 months (p = 0.006). The 27 T1A VS patients with serviceable hearing maintained this status, and an additional patient with nonserviceable hearing improved to serviceable hearing; among T1B VS patients, only 2 of the 5 patients with serviceable hearing remained as such, 2 evolved to nonserviceable hearing, and 1 lost hearing after surgery (p = 0.0022). T1B VS patients had a 24-fold risk of facial nerve deterioration (relative risk [RR] 25.2, 95% CI 1.42-448.57, p = 0.028) and a 32-fold risk of hearing deterioration (RR 32.7, 95% CI 1.93-553, p = 0.016) after surgery.

CONCLUSIONS

In intracanalicular VS, postoperative cochlear and facial nerve function are directly related to the location of the tumor in relation to the nerves, with worse outcomes in cases where the tumor is located between the vestibular and facial-cochlear nerves.

Elucidating the Mechanisms of Pulsed Radiofrequency for Pain Treatment

Pulsed radiofrequency is a well-documented treatment option for multiple painful conditions where pulses of energy are delivered close to neural elements. Since its earliest adoption, this technique has gained increasing acceptance as a minimally invasive procedure, and new applications are evolving. Studies have shown microscopic and biochemical changes that reflect beneficial effects; however, the exact mechanism of action is not yet completely understood. To redress this paucity, 11,476 articles of scientific relevance published between 1980 and November 2022 were mined through a search of the PubMed database, arriving at 49 studies both in animals and humans. In general, the experimental studies examined have shown that pulsed radiofrequency induces multiple changes with antinociceptive and neuromodulatory effects. These modifications include changes in neural and glial cells, synaptic transmission, and perineural space. Studies also reveal that pulsed radiofrequency regulates inflammatory responses, cellular signaling proteins, and the expression of genes related to pain transmission, acting in biological processes in structures such as myelin, mitochondria, axons, glial cells, connective tissue, regulation of proteins, ion channels, and neurotransmitters.

Trigeminal Neuralgia Due to Unilateral Early Bifurcated Superior Cerebellar Artery: Case Report and Literature Review

Trigeminal neuralgia (TN) is considered a debilitating pain syndrome resulting from a neurovascular conflict in the prepontine cistern, usually through compression of the trigeminal nerve by the superior cerebellar artery (SCA), resulting in neural pathology at the root entry zone. This is a case report of a patient whose TN symptoms were attributed to an anatomical variant of the SCA, managed successfully through conservative treatment. Anatomical variants of the SCA have been related to TN. However, this is the first reported case in the PubMed literature of primary TN due to an unilateral early bifurcated SCA treated conservatively with first-line sodium channel blockers with a good outcome.

Randomized Clinical Trials and Observational Tribulations: Providing Clinical Evidence for Personalized Surgical Pain Management Care Models

Proving clinical superiority of personalized care models in interventional and surgical pain management is challenging. The apparent difficulties may arise from the inability to standardize complex surgical procedures that often involve multiple steps. Ensuring the surgery is performed the same way every time is nearly impossible. Confounding factors, such as the variability of the patient population and selection bias regarding comorbidities and anatomical variations are also difficult to control for. Small sample sizes in study groups comparing iterations of a surgical protocol may amplify bias. It is essentially impossible to conceal the surgical treatment from the surgeon and the operating team. Restrictive inclusion and exclusion criteria may distort the study population to no longer reflect patients seen in daily practice. Hindsight bias is introduced by the inability to effectively blind patient group allocation, which affects clinical result interpretation, particularly if the outcome is already known to the investigators when the outcome analysis is performed (often a long time after the intervention). Randomization is equally problematic, as many patients want to avoid being randomly assigned to a study group, particularly if they perceive their surgeon to be unsure of which treatment will likely render the best clinical outcome for them. Ethical concerns may also exist if the study involves additional and unnecessary risks. Lastly, surgical trials are costly, especially if the tested interventions are complex and require long-term follow-up to assess their benefit. Traditional clinical testing of personalized surgical pain management treatments may be more challenging because individualized solutions tailored to each patient's pain generator can vary extensively. However, high-grade evidence is needed to prompt a protocol change and break with traditional image-based criteria for treatment. In this article, the authors review issues in surgical trials and offer practical solutions.

Retrosigmoid Craniotomy and Intradural Variations: Role of Patient-specific Preoperative Imaging to Identify Landmarks and Relevant Structures

OBJECTIVE

There are several landmarks to safely identify the limits of the retrosigmoid approach and its intradural variations, however, little has been discussed about how those landmarks may vary among patients.

METHOD

We provided a review of patient positions, surface landmarks for the retrosigmoid craniotomy, and structures to recognize for transmeatal, suprameatal, suprajugular and transtentorial extensions.

RESULTS

The position of the dural sinuses in relation with the zygomatic-inion line, and digastric notch line is readily identified on MRI. For transmeatal drilling, the position of the semicircular canals, vestibular aqueduct and jugular bulb is best evaluated on CT. For suprameatal drilling, the labyrinth and the position and integrity of the carotid canal are relevant to plan the anterior extension of the approach. For transtentorial extension, it is desirable to identify incisural structures. For suprajugular drilling, the position of the jugular bulb, invasion of venous structures, and integrity of the roof of the jugular foramen must be checked preoperatively.

CONCLUSION

The retrosigmoid approach is the workhorse of posterior skull base surgery. By recognizing patient-specific variations in known landmarks, the approach may be tailored prevent complications.

A Rare Case of an Intrasellar Arachnoid Cyst With Middle Cranial Fossa Extension

Intrasellar arachnoid cysts represent around 1% of all selar lesions. Generally, patients are asymptomatic and when they exhibit visual and/or hormonal disturbances, the indication for surgery is prompted. A 51-year-old woman with a known purely intrasellar arachnoid cyst diagnosed 23 years prior to presentation, evolved with gradual campimetric evaluation. Magnetic resonance imaging showed significant growth of the lesion, now extending into the left middle fossa through the cavernous sinus. The patient underwent cyst fenestration via the transsphenoidal approach. This is the first case in the literature of a patient with an intrasellar arachnoid cyst extending into the middle cranial fossa.

The Changing Environment in Postgraduate Education in Orthopedic Surgery and Neurosurgery and Its Impact on Technology-Driven Targeted Interventional and Surgical Pain Management: Perspectives from Europe, Latin America, Asia, and The United States

Personalized care models are dominating modern medicine. These models are rooted in teaching future physicians the skill set to keep up with innovation. In orthopedic surgery and neurosurgery, education is increasingly influenced by augmented reality, simulation, navigation, robotics, and in some cases, artificial intelligence. The postpandemic learning environment has also changed, emphasizing online learning and skill- and competency-based teaching models incorporating clinical and bench-top research. Attempts to improve work-life balance and minimize physician burnout have led to work-hour restrictions in postgraduate training programs. These restrictions have made it particularly challenging for orthopedic and neurosurgery residents to acquire the knowledge and skill set to meet the requirements for certification. The fast-paced flow of information and the rapid implementation of innovation require higher efficiencies in the modern postgraduate training environment. However, what is taught typically lags several years behind. Examples include minimally invasive tissue-sparing techniques through tubular small-bladed retractor systems, robotic and navigation, endoscopic, patient-specific implants made possible by advances in imaging technology and 3D printing, and regenerative strategies. Currently, the traditional roles of mentee and mentor are being redefined. The future orthopedic surgeons and neurosurgeons involved in personalized surgical pain management will need to be versed in several disciplines ranging from bioengineering, basic research, computer, social and health sciences, clinical study, trial design, public health policy development, and economic accountability. Solutions to the fast-paced innovation cycle in orthopedic surgery and neurosurgery include adaptive learning skills to seize opportunities for innovation with execution and implementation by facilitating translational research and clinical program development across traditional boundaries between clinical and nonclinical specialties. Preparing the future generation of surgeons to have the aptitude to keep up with the rapid technological advances is challenging for postgraduate residency programs and accreditation agencies. However, implementing clinical protocol change when the entrepreneur-investigator surgeon substantiates it with high-grade clinical evidence is at the heart of personalized surgical pain management.

Fiber-Optic Intracranial Pressure Monitoring System Using Wi-Fi-An In Vivo Study

BACKGROUND

Continuous invasive monitoring of intracranial pressure (ICP) is essential in neurocritical care for surveillance and management of raised ICP. Fluid-based systems and strain gauge microsensors remain the current standard. In the past few decades, several studies with wireless monitoring were developed aiming to reduce invasiveness and complications.

OBJECTIVE

To describe a novel Wi-Fi fiber-optic device for continuous ICP monitoring using smartphone in a swine model.

METHODS

Two ICP sensors (wireless prototype and wire-based reference) were implanted in the cerebral parenchyma of a swine model for a total of 120 minutes of continuous monitoring. Every 5 minutes, jugular veins compression was performed to evaluate ICP changes. The experimentation was divided in 3 phases for comparison and analysis.

RESULTS

Phase 1 showed agreement in ICP changes for both sensors during jugular compression and releasing, with a positive and strong Spearman correlation (r = 0.829, P < .001). Phase 2 started after inversion of the sensors in the burr holes; there was a positive and moderately weak Spearman correlation (r = 0.262, P < .001). For phase 3, the sensors were returned to the first burr holes; the prototype behaved similarly to the reference sensor, presenting a positive and moderately strong Spearman correlation (r = 0.669, P < .001).

CONCLUSION

A Wi-Fi ICP monitoring system was demonstrated in a comprehensive and feasible way. It was possible to observe, using smartphone, an adequate correlation regarding ICP variations. Further adaptations are already being developed.

Perfusion-weighted imaging in vestibular schwannoma: the influence that cystic status and tumor size have on perfusion profiles

Objective

The perfusion profile of vestibular schwannomas (VSs) and the factors that influence it have yet to be determined.

Materials and Methods

Twenty patients with sporadic VS were analyzed by calculating parameters related to the extravascular extracellular space (EES)-the volume transfer constant between a vessel and the EES (Ktrans); the EES volume per unit of tissue volume (Ve); and the rate transfer constant between EES and blood plasma (Kep)-as well as the relative cerebral blood volume (rCBV), and by correlating those parameters with the size of the tumor and its structure (solid, cystic, or heterogeneous).

Results

Although Ktrans, Ve, and Kep were measurable in all tumors, rCBV was measurable only in large tumors. We detected a positive correlation between Ktrans and rCBV (r = 0.62, p = 0.031), a negative correlation between Ve and Kep (r = -0.51, p = 0.021), and a positive correlation between Ktrans and Ve only in solid VSs (r = 0.64, p = 0.048). Comparing the means for small and large VSs, we found that the former showed lower Ktrans (0.13 vs. 0.029, p < 0.001), higher Kep (0.68 vs. 0.46, p = 0.037), and lower Ve (0.45 vs. 0.83, p < 0.001). The mean Ktrans was lower in the cystic portions of cystic VSs than in their solid portions (0.14 vs. 0.32, p < 0.001), as was the mean Ve (0.37 vs. 0.78, p < 0.001). There were positive correlations between the solid and cystic portions for Ktrans (r = 0.71, p = 0.048) and Kep (r = 0.74, p = 0.037).

Conclusion

In VS, tumor size appears to be consistently associated with perfusion values. In cystic VS, the cystic portions seem to have lower Ktrans and Ve than do the solid portions.

Uncommon Glioneuronal Tumors: A Radiologic and Pathologic Synopsis

Glioneuronal tumors are characterized exclusively by neurocytic elements (neuronal tumors) or a combination of neuronal and glial features (mixed neuronal-glial tumors). Most of these tumors occur in young patients and are related to epilepsy. While ganglioglioma, dysembryoplastic neuroepithelial tumor, and desmoplastic infantile tumor are common glioneuronal tumors, anaplastic ganglioglioma, papillary glioneuronal tumor, rosette-forming glioneuronal tumor, gangliocytoma, and central neurocytoma are less frequent. Advances in immunohistochemical and molecular diagnostics have improved the characterization of these tumors and favored the description of variants and new subtypes, some not yet classified by the World Health Organization. Not infrequently, the histologic findings of biopsies of glioneuronal tumors simulate low-grade glial neoplasms; however, some imaging findings favor the correct diagnosis, making neuroimaging essential for proper management. Therefore, the aim of this review was to present key imaging, histopathology, immunohistochemistry, and molecular findings of glioneuronal tumors and their variants.

Retrosigmoid Infralabyrinthine (Suprajugular) Approach to the Jugular Foramen: Indications, Limitations, and Surgical Nuances

BACKGROUND

Among the several approaches described to the jugular foramen (JF), the retrosigmoid infralabyrinthine (suprajugular) approach was one of the most recently described.

OBJECTIVE

To describe the indications, limitations, and operative nuances of the suprajugular approach.

METHODS

We provided a pertinent review of the anatomy, indications, preoperative evaluation, surgical steps and nuances, and postoperative management.

RESULTS

The suprajugular approach is suitable for tumors occupying the intracranial compartment with limited extension into the JF. Volume, width, and configuration of the foramen dictate the feasibility of the approach. Tumors invading the venous system are not suitable for this approach. Preoperative 3-dimensional MRI and computed tomography are used to evaluate intrajugular extension, relationship between the tumor and the jugular bulb (JB), venous system invasion, and shape of the JF. During surgery, exposition of the entire posterior border of the sigmoid sinus is needed and removing the bone over the JB. After identification of the JF, the jugular notch and intrajugular process of the roof of the foramen are removed and intrajugular resection is completed. In cases of high-riding JB, it may be gently pushed down to allow visualization of the anterior foramen. In cases of JB laceration, it may be repaired using a muscle patch and usually does preclude further resection.

CONCLUSION

The suprajugular approach is variation of the retrosigmoid approach that, when properly indicated, provides excellent exposure of the medial JF, with most anatomical variations and intraoperative complications predicted by a comprehensive preoperative evaluation.

Relationship between Signal Intensity of the Labyrinth and Cochleovestibular Testing and Morphologic Features of Vestibular Schwannoma

Objectives The aim of this article was to evaluate the relationship between signal intensity of the labyrinth and vestibulocochlear function and morphologic features of vestibular schwannoma (VS).

Design Cross-sectional Study.

Setting Tertiary referral center.

Participants Fifty-four patients with sporadic, untreated VS.

Main Outcome Measure Signal intensity of the cochlea and vestibule (SIRc and SIRv: signal intensity of cochlea/vestibule compared with cerebellar signal intensity; AURc and AURv: SIRc/SIRv of the affected side compared with the unaffected side) in 1.5T T2-weighted images was correlated with size (Hannover classification), cystic status, distance from the fundus of the internal auditory canal, video head impulse test (vHIT), and audiometry.

Results Signal intensity of the vestibule was higher than that of the cochlea (p < 0.01). Large tumors had lower SIRc than smaller tumors (p = 0.03); Hannover T1 tumors had higher SIRc (p < 0.01), SIRv (p < 0.01), AURc (p < 0.01) and AURv (p < 0.01) than the rest; heterogenous and cystic tumors had higher SIRv than solid large tumors (p = 0.02); superior vestibular nerve pattern on vHIT had higher SIRv and AURv than inferior vestibular nerve and mixed patterns (p = 0.03 and 0.004, respectively); and there was a weak correlation between AURv and speech discrimination (r = 0.33, p = 0.04).

Conclusion A more abnormal signal intensity of the labyrinth is associated with larger size and solid status of VS. There was a positive relationship between signal intensity of the labyrinth and speech discrimination scores on audiogram.

Management of jugular bulb injury during retrosigmoid transmeatal resection of vestibular schwannoma

Inadvertent laceration of the jugular bulb is a potentially serious complication of the retrosigmoid transmeatal approach to vestibular schwannomas. Here, the authors present the case of a 51-year-old woman with a right Hannover T4a vestibular schwannoma and bilateral high-riding jugular bulb, which was opened during drilling of the internal auditory canal (IAC). They highlight the immediate management of this complication, technical nuances for closing the defect without occluding the jugular bulb, and modifications of the standard technique needed to continue surgical resection. The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID2155.

Dorsal displacement of the facial nerve in vestibular schwannoma surgery

The course of the facial nerve (FN) has been extensively investigated in patients with vestibular schwannomas (VSs). FN running dorsally to the tumor capsule accounts for less than 3% of the cases. Diffusion tensor imaging (DTI)–based fiber tracking helps to preoperatively identify the FN. During surgery, a higher risk of injury is associated with the dorsal location of the FN. The authors demonstrate the nuances and tricks to identify and preserve a dorsal displaced FN during resection of a large VS, T3b according to the Hannover classification, through the retrosigmoid-transmeatal approach.

The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID2182

Brainstem hyperintensity in patients with vestibular schwannoma is associated with labyrinth signal on magnetic resonance imaging but not vestibulocochlear tests

OBJECTIVES

Focal hyperintensity in the dorsal brainstem (HDB) has been described in large cerebellopontine angle tumours and is thought to represent vestibular nuclei degeneration, but its functional significance has not been thoroughly investigated. Our aim was to analyse its relationship to imaging characteristics of the tumour and inner-ear structures and to vestibulocochlear functional tests.

METHODS

We retrospectively reviewed 54 patients with a histological diagnosis of vestibular schwannoma (VS). Magnetic resonance imaging tumour characteristics (size, cystic composition and distance from the cochlear aperture), signal intensity ratio of the cochlea and vestibule in fluid-attenuated inversion recovery (FLAIR) and fast imaging employing steady-state acquisition (FIESTA)/fast spin-echo imaging with variable flip angles (CUBE) and vestibulocochlear function tests (audiometry, auditory brainstem response (ABR) and video head impulse testing (vHIT)) were obtained. Statistical analyses were performed to evaluate their relation to focal HDB.

RESULTS

Focal HDB was found in 22% of VS. It was significantly associated with large (p < 0.001) and cystic (p = 0.004) tumours and also with tumours located further from the cochlear aperture (p = 0.039). The signal intensity ratio of the cochlea on FLAIR was higher in patients with HDB (p < 0.014), but this difference was not observed in FIESTA/CUBE (p = 0.981). Audiometry, ABR and vHIT results did not significantly differ in patients with HDB, but ABR results were worse in patients with higher cochlear signal intensity on FLAIR sequences (p = 0.026).

CONCLUSIONS

Focal HDB in patients with VS was associated with increased signal intensity ratio of the cochlea on FLAIR in patients with VS but not directly to the results of vestibulocochlear function tests.

Correlation of Intraoperative Neurophysiological Parameters and Outcomes in Patients with Intramedullary Tumors

Introduction

Intramedullary spinal cord tumors (IMSCT) account for about 2%-4% of all central nervous system tumors. Surgical resection is the main treatment step, but might cause damage to functional tissues. Intraoperative neuromonitoring (IONM) is an adopted measure to decrease surgical complications. Below, we describe the results of IMSCT submitted to surgery under IONM at a tertiary institution.

Methods

The sample consisted of consecutive patients with IMSCT admitted to the Neurological Institute of Curitiba from January 2007 to November 2016. A total of 47 patients were surgically treated. Twenty-three were male (48.9%) and 24 were female (51.1%). The mean age was 42.77 years. The mean follow-up time was 42.7 months.

Results

Neurological status improved in 29 patients (62%), stable in 6 (13%), and worse in 12 (25%). Patients who presented with motor symptoms at initial diagnosis had a worse outcome compared to patients with sensory impairment and pain (P = 0.026). Patients with a change in electromyography had worse neurological outcomes compared to patients who did not show changes in monitoring (P = 0.017).

Discussion and Conclusion

No prospective randomized high evidence study has been performed to date to compare clinical evolution after surgery with or without monitoring. In our sample, surgical resection was well succeeded mainly in oligosymptomatic patients with low preoperative McCormick classification and no worsening of IONM during surgery. We believe that microsurgical resection of IMSCT with simultaneous IONM is the gold standard treatment and achieved with good results.

Serial Tap Test of patients with idiopathic normal pressure hydrocephalus: impact on cognitive function and its meaning

Background

Idiopathic normal pressure hydrocephalus (INPH) is characterized by gait disturbance, urinary incontinence and cognitive decline. Symptoms are potentially reversible and treatment is based on cerebrospinal fluid shunting. The tap test (TT) is used to identify patients that will benefit from surgery. This procedure consists of the withdrawal of 20 to 50 mL of cerebrospinal fluid (CSF) through a lumbar puncture (LP) after which the symptoms of the triad are tested. Improvement in the quality and speed of gait are already recognized but cognitive improvement depends on several factors such as tests used, the time elapsed after LP for re-testing, and the number of punctures. Serial punctures may trigger similar conditions as external lumbar drainage (ELD) to the organism.

Objective

This study aimed to identify how serial punctures affect cognition to increase the sensitivity of the test and consequently the accuracy of surgical indication.

Methods

Sixty-one patients with INPH underwent baseline memory and executive tests repeatedly following the 2-Step Tap Test protocol (2-STT – two procedures of 30 mL lumbar CSF drainage separated by a 24-h interval). The baseline scores of INPH patients were compared with those of 55 healthy controls, and with intragroup post-puncture scores of the 2-STT.

Results

The group with INPH had lower performance than the control group in all cognitive tests (RAVLT, Stroop, CFT, FAR-COWA, FAB, MMSE, orientation, mental control), except for the forward digit span test (p = 0.707). After conducting LP procedures, the Stroop test (words, colors and errors), RAVLT (stage A1, A6 and B1), and CFT (immediate and delayed R) scores were equal to those of the control group (p > 0.05). The INPH group presented significant improvement after the first puncture in MMSE (p = 0.031) and in the Stroop Test (points) (p < 0.001). After the second puncture, subjects improved in orientation, MMSE, RAVLT (B1), Stroop (points, words, errors) and CFT (IR).

Conclusion

Progressive cognitive improvement occurred over the 2-STT and changes were more significant after the second LP in all cognitive domains except for RAVLT (A7). Encephalic alert system ‘arousal’ seems to participate in early improvements observed during 2-STT. The second LP increased the sensitivity of the drainage test to detect changes in cognitive variables, and consequently improved the quality of the method.

Using Cranial Sutures in a Single-Step Frame-Guided Resection and Reconstruction for Intraosseous Meningiomas: Technical Note

BACKGROUND

Single-stage surgical treatment of cranial intraosseous meningiomas includes complete tumor resection followed by aesthetic reconstruction. Tailored tumor resection with a computer-aided design/computer-aided manufacturing custom-made implant for the defect has been advocated in recent years to achieve a satisfactory cosmetic result with reduced operative time and fewer complications. However, several technical nuances related to the area of osseous removal may compromise cranioplasty.

METHODS

We present 2 cases of intraosseous meningiomas (sphenoid wing and retromastoid) to illustrate a step-by-step approach, from preoperative planning to single-step surgery.

RESULTS

For each case, a customized frame template delimiting bone removal was designed using cranial sutures as anatomical landmarks for precise placement of the cranioplasty template over the area of interest.

CONCLUSIONS

Custom templates based in cranial sutures may benefit single-step frame-guided resection and reconstruction of intraosseous tumors with compelling results.

Cranioplasty with three-dimensional customised mould for polymethylmethacrylate implant: a series of 16 consecutive patients with cost-effectiveness consideration

Background

Different methods of cranioplasty for the reconstruction of bony skull defects exist. In the absence of the autologous bone flap, a customised manufactured implant may be the optimal choice, but this implant has several limitations regarding its technical standardisation and better cost-effectiveness.

Methods

This study presents a series of 16 consecutive patients who had undergone cranioplasty with customised three-dimensional (3D) template moulds for polymethylmethacrylate (PMMA) implants manufactured after 3D modelling on a specific workstation. The virtual images were transformed into a two-piece physical model using a 3D printer for the biomaterials. PMMA implant was produced intraoperatively with the custom mould. Cosmetic results were analysed by comparing pre- and postoperative 3D computed tomography (CT) images and asking if the patient was satisfied with the result.

Results

The average total time for planning and production of customised mould was 10 days. The 16 patients were satisfied with the result, and CT images presented harmonious symmetry when comparing pre- and postoperative scans. Cases of postoperative infection, bleeding, or reoperation in this series were not observed.

Conclusion

Cranioplasty with high-technology customised 3D moulds for PMMA implants can allow for an aesthetic reconstruction with a fast and cost-effective manufacturing process and possibly with low complication rates.

Image Fusion in Neurovascular Compression Syndrome Related to Hemifacial Spasm

Neurovascular compression syndromes have well characterized clinical symptoms, but precise identification of the pathologic contact between the nerves and vessels can be challenging at neuroimaging. Considering that neurovascular contacts are frequent imaging findings in asymptomatic patients, correct visualization of pathological contact is crucial for the diagnosis and surgical planning. We have used magnetic resonance imaging fusion by overlaying color-coded T1-weighted postcontrast onto high-resolution T2-weighted images to better delineate imaging findings by enhancing vascular structures.

CGRP: from history to clinical application - A review

The role of calcitonin gene-related peptide (CGRP) and its receptor have played an important role in migraine for the last decades due to development of therapies that target their receptors at the trigeminal pain system, aiming at prevention or relief of acute migraine attacks. At first, CGRP receptor antagonists, called gepants have demonstrated appropriate effectiveness. In addition, they did not cause vasoconstriction, one of the drawbacks of triptans. However, their use had to be discontinued due to the risk of liver toxicity. Humanized monoclonal antibodies towards CGRP and the CGRP receptor have been developed as an alternative approach to block CGRP transmission. Still, there are some questions not fully answered as where CGRP and its receptor are located, how they influence the mechanisms of migraine attacks and if the blood brain barrier has any sort of importance. There is still much to learn about CGRP and migraine pathophysiology, especially its anatomical target sites and anti-CGRP agents. This paper presents a review of CGRP, including a brief history, focusing in CGRP mechanism, updates and future treatments.

Video Head Impulse Test to Preoperatively Identify the Nerve of Origin of Vestibular Schwannomas

BACKGROUND

Identification of the nerve of origin in vestibular schwannoma (VS) is an important prognostic factor for hearing preservation surgery. Thus far, vestibular functional tests and magnetic resonance imaging have not yielded reliable results to preoperatively evaluate this information. The development of the video head impulse test (vHIT) has allowed a precise evaluation of each semicircular canal, and its localizing value has been tested for some peripheral vestibular diseases, but not for VS.

OBJECTIVE

To correlate patterns of semicircular canal alteration on vHIT to intraoperative identification of the nerve of origin of VSs.

METHODS

A total 31 patients with sporadic VSs were preoperatively evaluated with vHIT (gain of vestibule-ocular reflex, overt and covert saccades on each semicircular canal) and then the nerve of origin was surgically identified during surgical resection via retrosigmoid approach. vHIT results were classified as normal, isolated superior vestibular nerve (SVN) pattern, isolated inferior vestibular nerve (IVN) pattern, predominant SVN pattern, and predominant IVN pattern. Hannover classification, cystic component, and distance between the tumor and the end of the internal auditory canal were also considered for analysis.

RESULTS

Three patients had a normal vHIT, 12 had an isolated SVN pattern, 5 had an isolated IVN pattern, 7 had a predominant SVN pattern, and 4 had a predominant IVN pattern. vHIT was able to correctly identify the nerve of origin in 89.7% of cases (100% of altered exams).

CONCLUSION

The pattern of semicircular canal dysfunction on vHIT has a localizing value to identify the nerve of origin in VSs.

Facial Nerve Adherence in Vestibular Schwannomas: Classification and Radiological Predictors

Background Facial nerve palsy is one of the most frequent complications after resection of vestibular schwannomas (VS). Several mechanisms have been implicated in the poor postoperative facial nerve outcome. Adherence between the facial nerve and tumor capsule is one of the most relevant factors. There is no clear preoperative parameter permitting identification of these adhesions.

Objective The aim of this study was to identify the correlation between the grade of adherence of the facial nerve to the tumor capsule and its functional outcome after VS resection.

Methods A total of 26 patients with sporadic VS (tumor sized T3, T4A, and T4B according to Hannover classification) were evaluated. Grade of adherence of the facial nerve to the tumor capsule was checked during surgery and graduated according to a proposed scale into 1 to 3 different grades. Facial nerve function was assessed postoperatively and after 1-year follow-up. Size of tumor according to Hannover classification, presence of cystic components, “cerebrospinal fluid (CSF) cleft sign,” and the contour of tumor capsule were tested as radiological predictors of grade of adherence to the facial nerve.

Results and Conclusion Only Grade 2 (11 cases) and 3 (15 cases) of adherence were seen in large VS. Lower grade of adherence was associated with good facial nerve outcome after 1-year follow-up (p = 0.029). Presence of the “CSF cleft sign” and regular contour of tumor capsule were independent predictors of adherence. When both factors were associated, sensitivity and specificity of this method were 83 and 80%, respectively.

Microsurgical Anatomy of the Jugular Foramen Applied to Surgery of Glomus Jugulare via Craniocervical Approach

The jugular foramen remains one of the most complex regions of the human body. Approaching lesions in this area requires extensive anatomical knowledge and experience, due to the many critical neurovascular structures passing through or around the jugular foramen. Here, we present a concise review of the microsurgical anatomy of the jugular foramen in relation to the craniocervical approach.

Video Head Impulse Test in Vestibular Schwannoma: Relevance of Size and Cystic Component on Vestibular Impairment

OBJECTIVES

Tumor factors that influence vestibular function in vestibular schwannoma (VS) have not been properly described. We evaluated whether cystic VSs have different vestibular function than solid VS. Tumor size on vestibular function was also evaluated.

STUDY DESIGN

Cross-sectional study.

SETTING

Tertiary referral center.

PATIENTS

Forty-one cases of sporadic, untreated VS.

INTERVENTION

Evaluation with video head impulse test and MRI.

MAIN OUTCOME MEASURES

Tumors were classified as solid, heterogeneous, or cystic and by size using the Hannover classification. Vestibulo-ocular reflex (VOR) gain was correlated to tumor size and cystic status.

RESULTS

Large VS had worse VOR gain than small lesions (p < 0.001). Cystic lesions had lower VOR gain than all other tumors (p = 0.001), Hannover T3 and T4 (p = 0.014), Hannover T4 (p = 0.015), solid tumors (p < 0.001), solid Hannover T3 and T4 (p = 0.003), and solid Hannover T4 (p = 0.008). Heterogeneous VSs had lower VOR gain compared to solid tumors (p = 0.02), solid Hannover T3 and T4 (p = 0.08), and solid Hannover T4 (p = 0.14). Heterogeneous and cystic VSs had lower VOR gain than solid tumors (p < 0.001), solid Hannover T3 and T4 (p = 0.004), and solid Hannover T4 (p = 0.02). VOR gain of solid T4 lesions was not significantly lower than solid Hannover T1-T3 (p = 0.33).

CONCLUSION

Cystic status is directly associated with a worse vestibular dysfunction. Size did not significantly impact vestibular function in solid VS.

Gamma knife radiosurgery for trigeminal neuralgia: first case series from Latin America

INTRODUCTION

Gamma Knife® radiosurgery (GKRS) for trigeminal neuralgia is an effective treatment with at least a 50% reduction of pain in 75-95% of patients.

OBJECTIVE

To present the first series of patients treated for trigeminal neuralgia using GKRS in Latin America.

METHODS

Retrospective analysis. Analysis consisted of time to improvement of symptoms, best Barrow Neurological Institute scale (BNI) score after procedure, time without pain, time to recurrence and post-procedural hypoesthesia.

RESULTS

Nineteen cases of classical trigeminal neuralgia were analyzed and three cases of symptomatic trigeminal neuralgia were described. Mean time from symptom onset to radiosurgery was 99.6 months, and 78.9% of patients had undergone invasive procedures before treatment. Patients were followed for a mean of 21.7 months. BNI I was achieved in 36.8%, IIIa in 21.1%, IIIb in 21.1%, IV in 5.3% and V in 15.7%. New hypoesthesia developed in 12.1% patients, which was associated with achieving BNI I after the procedure (p < 0.05). Time from diagnosis to GKRS was higher in patients who failed to achieve BNI I (143 vs. 76 months). The distance from the root entry zone in patients who achieved BNI I was greater than patients who did not (1.94 vs. 1.14 mm). Mean distance from the root entry zone in patients with new hypoesthesia was 2.85 mm vs. 1.06 mm (p = 0.06).

CONCLUSION

Clinical response to GKRS is related to the time between diagnosis and procedure, thus its indication should be considered early in the management of these patients.

Modified Craniocervical Approach for Resection of the Styloid Process in Patients with Eagle's Syndrome

Objective  Surgical treatment of Eagle's syndrome remains the mainstay of treatment. Palsy of the marginal mandibular branch of the facial nerve is the most significant complication encountered in transcervical resections, due to direct compression during the approach. We proposed a modification of the craniocervical approach to the jugular foramen to resect the styloid process avoiding the marginal mandibular branch and subsequent palsy. Design  This is a single-center retrospective cohort study. Setting  The research was conducted at a tertiary medical center. Participants  From November 2008 to October 2018, 12 patients with Eagle's syndrome underwent treatment using our modified approach. Main Outcome Measures  Demographic data, type of Eagle's syndrome, symptomatic side, size of the styloid process, clinical outcomes, and complications were analyzed. Results  Mean size of the styloid processes was of 3.34 cm on the operated side (2.3-4.7 cm) and 2.98 cm on the other (2-4.2 cm). Intraoperative facial nerve irritation occurred in one case. Resection of the entire styloid process was achieved in all cases. Eight cases experienced complete improvement, three cases had a partial response, and one case failed to improve. There were no cases of recurrence. Two patients presented transient postoperative auricular paresthesia. There were no cases of mandibular branch palsy, nor any other complications in our series. Conclusions  Our modified transcervical approach is effective in avoiding the marginal mandibular branch of the facial nerve, avoiding postoperative palsy.

How I do it: retrosigmoid suprajugular approach to the jugular foramen

BACKGROUND

The retrosigmoid suprajugular approach provides a less-aggressive approach for a subset of tumors of the jugular foramen.

METHOD

We described the retrosigmoid suprajugular approach with its advantages, caveats, and indications. A Samii-B2 glossopharyngeal nerve schwannoma is shown to exemplify the procedure.

CONCLUSION

The retrosigmoid suprajugular approach provides an excellent option for tumors with a variable extension into the cerebellopontine cistern and limited extension into the jugular foramen. It is less destructive than the other approaches and allows a good exposure to the posterior part of the jugular foramen.

Salomón Hakim: the man behind normal pressure hydrocephalus

The illustrious Colombian Professor Salomón Hakim provided the annals of neurology with one of the most brilliant and original bodies of research on record, developing the concept of normal pressure hydrocephalus, as well as proving that ventricular shunting is an effective treatment. Thus, Professor Hakim proved that some of the dementias, at that time considered senile, could be successfully treated. Here the authors present an historical review of his main contributions, which continue to influence the study of dementia to this day.

Cerebellopontine angle schwannomas arising from the intermediate nerve: a scoping review

Intermediate nerve schwannomas (INS) are extremely rare lesions in literature. They have been described mimicking facial nerve schwannomas, but not vestibular schwannomas (VS). We aimed to review the previously published cases, as well as the evidence to believe that they are far more common, though usually misdiagnosed as facial or VS. We performed a review of PubMed/Medline and Embase of "intermediate nerve schwannoma," "facial nerve schwannoma," "greater superficial petrosal nerve schwannoma," "geniculate ganglion schwannoma," and "chorda tympani schwannoma" to identify all cases of INS, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) statement. Furthermore, 2 cases operated at our center are shown to exemplify the proposed hypotheses. No article was excluded from review. Thirteen cases of INS, 11 cases of chorda tympani schwannoma, and 18 cases of greater superficial petrosal nerve schwannoma were found in literature. In facial nerve schwannomas, the predilection of schwannomas for sensory nerves, and the ability to preserve the motor facial nerve during tumor resection support the hypothesis of intermediate nerve as the nerve of origin. For VSs, the different arachnoidal arrangement of medial VS, the sharing of pia mater by the intermediate nerve and vestibular nerve, and the medial Obersteiner-Redlich zone of the intermediate nerve, support the hypothesis of intermediate nerve origin of some VS. The correct identification of the intermediate nerve as a nerve of origin of cerebellopontine angle schwannomas is of uttermost importance, especially when mistaken for VS, as this may account for the heterogeneity of facial and cochlear outcomes after surgery.

Retrosigmoid Transmeatal Approach with 360-Degree Drilling of the Internal Auditory Canal for the Resection of Intracanalicular Meningioma

Introduction  Vestibular schwannomas are the most common lesions occupying the internal auditory canal (IAC); however, almost in 4 to 5% of meningiomas, metastases, cysts, lipomas, and cavernous malformations have been found in this location, mimicking schwannomas. Even though cerebellopontine angle (CPA) meningiomas with the involvement of the IAC are frequently encountered, the presence of a primary intracanalicular meningioma is rare. Objective  To show the technical nuances of the retrosigmoid-transmeatal approach to successfully achieve gross total resection (GTR) with preservation of facial and auditory function. Case Report  We present a left intracanalicular meningioma on a 60-year-old man with history of tinnitus and hearing loss. Magnetic resonance imaging (MRI) showed a left intracanalicular lesion completely obliterating the IAC and with minor extension to the CPA cistern, with the vestibulocochlear complex dislocated posteriorly, initially diagnosed as a Hannover's T2 vestibular schwannoma. The patient underwent a left retrosigmoid approach, and during the exposure of the lesion, the diagnosis of a meningioma became evident. The transmeatal phase of the approach was modified with a wide opening of the canal, including the anterior wall. Closure was performed using a muscle graft, duramater flap, and fibrin glue. Results  GTR was achieved and the patient developed a mild facial palsy (House-Brackmann grade III) which completely recovered within 3 months. Conclusions  The retrosigmoid transmeatal approach is suitable to achieve GTR in intracanalicular meningiomas. Some modifications of the approach intended for vestibular schwannomas are necessary and may be performed during the procedure. The link to the video can be found at: https://youtu.be/A9OXRFIl1e8 .

Gait in normal pressure hydrocephalus: characteristics and effects of the CSF tap test

ABSTRACT Normal pressure hydrocephalus (NPH), described by Hakim and Adams in 1965, is characterized by gait apraxia, urinary incontinence, and dementia. It is associated with normal cerebrospinal fluid (CSF) pressure and ventricular dilation that cannot be attributed to cerebral atrophy. Objectives: To evaluate gait characteristics in patients with idiopathic NPH and investigate the effect of the CSF tap test (CSF-TT) on gait. Methods: Twenty-five patients diagnosed with probable idiopathic NPH were submitted to the CSF-TT. The procedure aimed to achieve changes in gait parameters. Results: Fifteen gait parameters were assessed before and after the CSF-TT. Five showed a statistically significant improvement (p < 0.05): walking speed (p < 0.001), cadence (p < 0.001), step length (p < 0.001), en bloc turning (p = 0.001), and step height (p = 0.004). Conclusion: This study demonstrated that gait speed was the most responsive parameter to the CSF-TT, followed by cadence, step length, en bloc turning, and step height.

First case of V180I rare mutation in a Brazilian patient with Creutzfeldt-Jakob disease

Here, we report the first case of V180I rare mutation in a Brazilian woman whose clinical condition started with memory impairment for recent events and insomnia with 2 months of evolution, without any other alterations in neurological examination. Both the electroencephalogram (EEG) and the routine biochemical examination of cerebrospinal fluid (CSF) were normal. CSF 14-3-3 protein search was positive. Magnetic resonance imaging (MRI) of the encephalon showed findings suggestive of Creutzfeldt-Jakob disease, confirmed by sequencing of PRNP gene that reveal V180I mutation also homozygosity for methionine at codon 129 (M129M).

Spontaneous intracranial epidural hematoma during rivaroxaban treatment

According to our research, this is the first case described in the literature of spontaneous intracranial epidural hematoma secondary to the use of Xareltor. Spontaneous intracranial epidural hematomas are rarely described in the literature. They are associated with infectious diseases of the skull, coagulation disorders, vascular malformations of the dura mater and metastasis to the skull. Long-term post-marketing monitoring and independent reports will probably detect the full spectrum of hemorrhagic complications of the use of rivaroxaban.

Elastomers three-dimensional biomodels proven to be a trustworthy representation of the angiotomographic images

ABSTRACT Intracranial aneurysm (IA) rupture is responsible for 80% of spontaneous arachnoid hemorrhages and associated with an extremely high mortality rate. Two possible surgical interventions are endovascular embolization and microsurgical clipping. Three-dimensional (3D) prototyping models help in surgical planning minimizing perioperative risks in both methods and reducing operating time. Methods 3D biomodels were printed with flexible material (elastomer) using angiotomographic DICOM acquired images and compared to 3D digital subtraction angiography (DSA) images. Results 3D biomodels represented the aneurysm angioarchitecture exactly, especially the neck and domus features. Conclusion Elastomers 3D biomodels proved to be a trustworthy representation of the angiotomographic images and could be used to help surgical planning in IA treatment.

Embolization of a giant hypervascularized choroid plexus papilloma with onyx by direct puncture: a case report

BACKGROUND

Choroid plexus papilloma is a rare intracranial neoplasm derived from choroid plexus epithelium accounting for less than 1 % of all brain tumors. These tumors are highly vascularized, and tumor resection is difficult, especially in small children, due to severe intraoperative bleeding. Preoperative embolization is helpful to reduce intraoperative bleeding, but it may not be possible in small children or if the tumor has no suitable feeding vessels for embolization.

METHODS

We present the case of a 2-year-old girl with a giant choroid plexus papilloma. An attempt of tumor resection was previously performed in another clinic, but the surgery was aborted due to massive intraoperative bleeding and only a biopsy was done. Angiography showed no suitable vessels for embolization. A new attempt of tumor removal was carried out, but again, severe intraoperative bleeding occurred and only a partial resection was possible. Intratumoral embolization with onyx through direct percutaneous puncture was performed.

RESULTS

Radical tumor removal was possible after two additional surgeries. Intraoperative blood loss was 345 ml (first surgery = only partial removal), 250 ml (second procedure = 1/3 of tumor volume resected), and 250 ml (third surgery = total removal). The patient presented no additional deficits.

CONCLUSIONS

Intratumoral percutaneous embolization with onyx was very helpful in reducing intraoperative bleeding in this case. Safe radical tumor resection was possible. This technique may be useful for those surgeons dealing with highly vascularized tumors, especially in small children. No report of intratumoral embolization with onyx in cases of intracerebral tumors could be found in the literature.

Surgical exposure of the internal auditory canal through the retrosigmoid approach with semicircular canals anatomical preservation

OBJECTIVE

Evaluate the feasibility of an adequate exposure with anatomical preservation of labyrinth structures through retrosigmoid transmeatal approach (RSA) in surgeries for resection of acoustic neuromas/vestibular schwannomas (VS).

METHOD

Thirty patients underwent surgical resection and were preoperatively evaluated with fine slice high definition CT scans and 3D-MRI volumetric reconstructions. Extension of internal auditory canal (IAC) opening during surgery was measured using 3 mm right-angle calibrated hook and neuronavigation parameters. Postoperatively, the extension of IAC opening and integrity of the labyrinth were confirmed through preoperatively images procedures.

RESULTS

The preoperative length of IACs varied between 7.8 and 12.0 mm (mean 9.3 mm, SD 0.98, 95%CI 8.9 to 9.6, and median 9.0 mm). Postoperative images demonstrated adequate opening of the IAC and semicircular channels integrity.

CONCLUSION

A complete drilling of the posterior wall of IAC through the RSA is feasible and allows direct visualization of the IAC-fundus without damaging the semicircular canals.

Microsurgical training model with nonliving swine head. Alternative for neurosurgical education

PURPOSE

This paper proposes a practical model of microneurosurgical training using a nonliving swine head.

METHODS

Fresh porcine heads were obtained from butchery and dissected at our Laboratory of Microsurgery. Brain and skull base surgery were trained under microscopic magnification.

RESULTS

Several neurosurgical procedures could be simulated in the nonliving pig model, including transcallosal approach to the lateral ventricle, lateral sulcus and middle fossa dissection, and posterior fossa surgery.

CONCLUSION

The swine model perfectly simulates standard microneurosurgical procedures, and is a useful tool for developing and refining surgical skills.

Rapid prototyping of three-dimensional biomodels as an adjuvant in the surgical planning for intracranial aneurysms

PURPOSE

To fabricate a three-dimensional biomodels of intracranial aneurysms, using rapid prototyping technology, to facilitate optimal anatomical visualization of aneurysms prior to and during surgery.

METHODS

Four intracranial aneurysms cases were selected for this study. Using CT angiography images, the rapid prototyping process was completed using a PolyJet technology machine. The size and morphology of the prototypes were compared to brain digital subtraction arteriography of the same patients.

RESULTS

The biomodels reproduced the exact location and morphology of the intracranial aneurysms, particularly the necks, in life-size dimensions and exactly the same as measured by digital subtraction arteriography. The arterial segments adjacent to the aneurysm and arteries anatomically known by the surgeon were also shown, which could guide the surgeon to the aneurysmal segment. The models showed an average unit cost of US$ 130 and each one took an average of 20 hours to be fabricated.

CONCLUSIONS

It is possible to fabricate 3D physical biomodels of intracranial aneurysms from CT angiography images. These prototypes may be useful in the surgical planning for intracranial aneurysms to clarify the anatomy, define surgical techniques and facilitate the choice of suitable materials, such as clips and clip appliers.