Prediction of pseudoprogression in post-treatment glioblastoma using dynamic susceptibility contrast-derived oxygenation and microvascular transit time heterogeneity measures

OBJECTIVES

To evaluate the added value of MR dynamic susceptibility contrast (DSC)-perfusion-weighted imaging (PWI)-derived tumour microvascular and oxygenation information with cerebral blood volume (CBV) to distinguish pseudoprogression from true progression (TP) in post-treatment glioblastoma.

METHODS

This retrospective single-institution study included patients with isocitrate dehydrogenase (IDH) wild-type glioblastoma and a newly developed or enlarging measurable contrast-enhancing mass within 12 weeks after concurrent chemoradiotherapy. CBV, capillary transit time heterogeneity (CTH), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2) were obtained from DSC-PWI. Predictors were selected using univariable logistic regression, and performance was measured with adjusted diagnostic odds with tumour volume and area under the curve (AUC) of receiver operating characteristics analysis.

RESULTS

A total of 103 patients were included (mean age, 59.6 years; 59 women), with 67 cases of TP and 36 cases of pseudoprogression. Pseudoprogression exhibited higher CTH (4.0 vs. 3.4, p = .019) and higher OEF (12.7 vs. 10.7, p = .014) than TP, but a similar CBV (1.48 vs. 1.53, p = .13) and CMRO2 (7.7 vs. 7.3s, p = .598). Independent of tumour volume, both high CTH (adjusted odds ratio [OR] 1.52; 95% confidence interval [CI]: 1.11-2.09, p = .009) and high OEF (adjusted OR 1.17; 95% CI:1.03-1.33, p = .016) were predictors of pseudoprogression. The combination of CTH, OEF, and CBV yielded higher diagnostic performance (AUC 0.71) than CBV alone (AUC 0.65).

CONCLUSION

High intratumoural capillary transit heterogeneity and high oxygen extraction fraction derived from DSC-PWI have enhanced the diagnostic value of CBV in pseudoprogression of post-treatment IDH-wild type glioblastoma.

CLINICAL RELEVANCE STATEMENT

In the early post-treatment stage of glioblastoma, pseudoprogression exhibited both high oxygen extraction fraction and high capillary transit heterogeneity and these dynamic susceptibility contrast-perfusion weighted imaging derived parameters have added value in cerebral blood volume-based noninvasive differentiation of pseudoprogression from true progression.

KEY POINTS

• Capillary transit time heterogeneity and oxygen extraction fraction can be measured noninvasively through processing of dynamic susceptibility contrast imaging. • Pseudoprogression exhibited higher capillary transit time heterogeneity and higher oxygen extraction fraction than true progression. • A combination of cerebral blood volume, capillary transit time heterogeneity, and oxygen extraction fraction yielded the highest diagnostic performance (area under the curve 0.71).

Surgical Strategy for Petroclival Meningioma-Related Trigeminal Neuralgia: The Role of Porus Trigeminus Opening

OBJECTIVE

Petroclival meningiomas invade Meckel's cave through the porus trigeminus, leading to secondary trigeminal neuralgia. Microsurgery and stereotactic radiosurgery (SRS) are the typical treatment options. This study investigated symptom control, outcomes, and surgical strategies for PC meningioma-induced TN.

METHODS

We retrospectively analyzed 28 TN patients with PC meningiomas who underwent microsurgical nerve decompression between January 2021 and February 2023. In all patients undergoing a transpetrosal approach, the porus trigeminus was opened to enable the removal of the entire tumor within Meckel's cave. Clinical outcomes were assessed using the Barrow Neurologic Institute (BNI) pain intensity scale. Risk factors for poor TN outcomes and poor facial numbness were analyzed.

RESULTS

Among 28 patients, 21 (75%) underwent the transpetrosal approach, 5 (17.9%) underwent the retrosigmoid approach, and 2 (7.1%) underwent the Dolenc approach. Following microsurgery, 23 patients (82.1%) experienced TN relief without further medication (BNI I or II). TN recurrence occurred in 2 patients (7.1%), and 3 patients (10.7%) did not achieve TN relief. Cavernous sinus invasion was significantly correlated with poor TN outcomes (P = 0.047). A history of previous SRS (P = 0.011) and upper clivus type tumor (P = 0.018) were significantly associated with poor facial numbness.

CONCLUSIONS

Microsurgical nerve decompression is effective in improving BNI scores in patients with TN associated with PC meningiomas. Considering the results of our study, the opening of the porus trigeminus can be considered as a suggested procedure in the treatment of PC meningiomas, especially in cases accompanied by TN.

Feasibility and efficacy of endoscopic transorbital optic canal decompression for meningiomas causing compressive optic neuropathy

OBJECTIVE

The endoscopic transorbital approach (ETOA) and transorbital anterior clinoidectomy have been suggested as novel procedures through which to reach the superolateral compartments of the orbit, allowing optic canal decompression. However, there is limited literature describing the technical details and surgical outcomes of these procedures. In this study, the authors aimed to analyze the feasibility and efficacy of endoscopic transorbital decompression of the optic canal through anterior clinoidectomy for compressive optic neuropathic lesions.

METHODS

Between 2016 and 2022, the authors performed ETOA for compressive optic neuropathic lesions in 14 patients. All these patients underwent transorbital anterior clinoidectomy through the surgically defined "intraorbital clinoidal triangle," which is composed of the roof of the superior orbital fissure, the medial margin of the optic canal, the medial border of the superior orbital fissure, and the optic strut. Demographic data, tumor characteristics, pre- and postoperative imaging, pre- and postoperative visual examinations, and surgical outcomes were retrospectively reviewed.

RESULTS

The mean age at the time of ETOA was 53.3 years (range 41-64 years), and the mean follow-up was 16.8 months (range 6.7-51.4 months). The inclusion criterion in this study was having a meningioma (14 patients). In the preoperative visual function examination, 7 patients with a meningioma showed progressive visual impairment. After endoscopic transorbital optic canal decompression, visual function improved in 5 patients, remained unchanged in 8 patients, and worsened in 1 patient. No new-onset neurological deficit was associated with ETOA and anterior clinoidectomy in any patients.

CONCLUSIONS

Endoscopic transorbital decompression of the optic canal with extradural anterior clinoidectomy is a safe and feasible technique that avoids significant injury to the clinoidal internal carotid artery and surrounding neurovascular structures.

Generative AI in glioma: ensuring diversity in training image phenotypes to improve diagnostic performance for IDH mutation prediction

BACKGROUND

This study evaluated whether generative artificial intelligence-based augmentation (GAA) can provide diverse and realistic imaging phenotypes and improve deep learning-based classification of isocitrate dehydrogenase (IDH) type in glioma compared with neuroradiologists.

METHODS

For model development, 565 patients (346 IDH-wildtype, 219 IDH-mutant) with paired contrast-enhanced T1 and FLAIR MRI scans were collected from tertiary hospital and The Cancer Imaging Archive. Performance was tested on internal (119, 78 IDH-wildtype, 41 IDH-mutant [IDH1 and 2]) and external test sets (108, 72 IDH-wildtype, 36 IDH-mutant). GAA was developed using score-based diffusion model and ResNet50 classifier. The optimal GAA was selected in comparison with null model. Two neuroradiologists (R1, R2) assessed realism, diversity of imaging phenotypes, and predicted IDH mutation. The performance of a classifier trained with optimal GAA was compared with that of neuroradiologists using area under the receiver operating characteristics curve (AUC). The effect of tumor size and contrast enhancement on GAA performance was tested.

RESULTS

Generated images demonstrated realism (Turing's test: 47.5%-50.5%) and diversity indicating IDH type. Optimal GAA was achieved with augmentation with 110 000 generated slices (AUC: 0.938). The classifier trained with optimal GAA demonstrated significantly higher AUC values than neuroradiologists in both the internal (R1, P=.003; R2, P<.001) and external test sets (R1, P<.01; R2, P<.001). GAA with large-sized tumors or predominant enhancement showed comparable performance to optimal GAA (internal test: AUC 0.956 and 0.922; external test: 0.810 and 0.749).

CONCLUSIONS

Application of generative AI with realistic and diverse images provided better diagnostic performance than neuroradiologists for predicting IDH type in glioma.

Defining subventricular zone involvement to predict the survival of patients in isocitrate dehydrogenase-wild type glioblastoma: validation in a prospective registry

OBJECTIVES

The prognostic value of subventricular zone distance (SVD) is unclear because of different definitions and lack of evaluation of clinical survival models. The aim of this study was to define SVD and evaluate its prognostic value in a survival nomogram for glioblastoma.

METHODS

This retrospective study included 158 (SVD biomarker) from historical glioblastoma patients and 187 (survival modeling) with IDH-wild type glioblastoma from a prospective registry (NCT02619890). SVD was assessed by two radiologists: definition 1, the distance between the tumor edge to subventricular zone (SVZ); definition 2, the distance between the tumor centroid to SVZ; definition 3, enhancement at the ventricular wall. The associations between SVD and overall survival (OS) were evaluated using multivariable Cox proportional hazards regression analysis. Performance of an updated SVD survival model was compared with that of the Radiation Therapy Oncology Group (RTOG) 0525 nomogram.

RESULTS

SVD according to both definition 1 (hazard ratio [HR]: 0.97, 95% CI: 0.94-0.99; p = .011) and definition 2 (HR: 0.96, 0.94-0.98, p < .001) was adversely associated with OS. Definition 1 was adversely associated with PFS (HR: 0.96, 0.94-0.99, p = .008) and showed the highest reproducibility (intraclass correlation coefficient, 0.90). The SVD-updated model showed similar to better performance than the RTOG model for predicting OS of up to 3 years (AUC: 0.735-0.738 vs. 0.687-0.708), with higher time-dependent specificity for 1-year (89.9% vs. 70.6%) and 3-year OS (93.3% vs. 80.0%).

CONCLUSION

SVZ distance is an independent adverse prognostic factor in patients with IDH-wild type glioblastoma. Updating the survival model with SVZ provides better time-dependent specificity and reproducibility.

KEY POINTS

• Subventricular zone distance (SVD) measurement from tumor edge showed high reproducibility. • Longer SVD was independently associated with longer overall survival. • Adding SVD improved time-dependent specificity for survival model in a prospective registry.

Indications and outcomes of endoscopic transorbital surgery for trigeminal schwannoma based on tumor classification: a multicenter study with 50 cases

OBJECTIVE

Trigeminal schwannoma is a rare CNS tumor and involves the multicompartmental skull base. Recently, the endoscopic transorbital approach (ETOA) has emerged as a technique for minimally invasive surgery. The objective of this study was to evaluate the optimal indications and clinical outcomes of the ETOA for trigeminal schwannomas based on their tumor classification.

METHODS

Between September 2016 and February 2022, the ETOA was performed in 50 patients with trigeminal schwannoma at four tertiary hospitals. There were 15 men and 35 women in the study, with a mean age of 46.9 years. All tumors were classified as type A (predominantly involving the middle cranial fossa), type B (predominantly involving the posterior cranial fossa), type C (dumbbell-shaped tumors involving the middle and posterior fossa), or type D (involvement of the extracranial compartment). Type D tumors were also subclassified by ophthalmic division (D1), maxillary division (D2), and mandibular division (D3). Clinical outcome was analyzed, including extent of resection and surgical morbidities.

RESULTS

In this study, overall gross-total resection (GTR) was performed in 35 (70.0%) of 50 patients and near-total resection (NTR) in 9 patients (18.0%). The mean follow-up period was 21.9 (range 1-61.7) months. There was no tumor regrowth or recurrence during the follow-up period. Based on the classification, there were 17 type A tumors, 20 type C, and 13 type D. There were no type B tumors. Of the 13 type D tumors, 7 were D1, 1 D2, and 5 D3. For type A tumors, GTR or NTR was achieved using an ETOA in 16 (94.1%) of 17 patients. Eighteen (90.0%) of 20 patients with type C tumors attained GTR or NTR. Ten (76.9%) of 13 patients with type D tumors underwent GTR. Statistical analysis showed that there was no significant difference in the extent of resection among the tumor subtypes. Surgical complications included transient partial ptosis (n = 4), permanent ptosis (n = 1), transient diplopia (n = 7), permanent diplopia (n = 1), corneal keratopathy (n = 7), difficulties in mastication (n = 5), and neuralgic pain or paresthesia (n = 14). There were no postoperative CSF leaks or enophthalmos during follow-up.

CONCLUSIONS

This study showed that trigeminal schwannomas can be effectively treated with a minimally invasive ETOA in all tumor types, except those predominantly involving the posterior fossa (type B). For the extracranial compartments, D2 or D3 tumor types often require an ETOA combined with the endoscopic endonasal approach, while D1 tumor types can be treated using an ETOA alone.

Corrigendum: Vestibular schwannoma associated with neurofibromatosis type 2: Clinical course following stereotactic radiosurgery

[This corrects the article DOI: 10.3389/fonc.2022.996186.].

Sphero-Conical Modeling for the Estimation of Very Long Baseline Interferometry Invariant Point

A geodetic reference frame is a fundamental element in geoinformation fields such as autonomous navigation and digital twins. The international terrestrial reference frame is established and maintained using several space-geodetic techniques, including very long baseline interferometry (VLBI) and satellite laser ranging (SLR). For several decades, geodesists have been devoted to connecting these two sensors at a site (local tie). The reference point of the VLBI antenna and SLR telescope, called invariant point (IVP), should be precisely determined to connect these two solutions. We developed an innovative integrated model to estimate the IVP, which is composed of spherical and conical models, depending on the rotational axis. In this model, all target points in 3D spaces were directly connected to the IVP; thus, the stability and robustness of the system were secured. Furthermore, all inherent errors in the coordinates were predicted by applying the total least-squares approach.

Differences in stromal component of chordoma are associated with contrast enhancement in MRI and differential gene expression in RNA sequencing

Chordoma is a malignant bone neoplasm demonstrating notochordal differentiation and it frequently involves axial skeleton. Most of chordomas are conventional type with varying amount of myxoid stroma. Previously known prognostic factors for conventional chordoma are not specific for chordoma: old age, metastasis, tumor extent, and respectability. Here, we aimed to investigate the histologic, radiologic, and transcriptomic differences in conventional chordoma based on the stromal component. A total of 45 patients diagnosed with conventional chordoma were selected between May 2011 and March 2020 from a single institution. Electronic medical records, pathology slides, and pretreatment magnetic resonance imaging (MRI) scans were reviewed. Of the 45 patients, ten cases (4 stroma-rich and 6 stroma-poor tumor) were selected for RNA sequencing, and available cases in the remainder were used for measuring target gene mRNA expression with qPCR for validation. Differential gene expression and gene set analysis were performed. Based on histologic evaluation, there were 25 (55.6%) stroma-rich and 20 (44.4%) stroma-poor cases. No clinical differences were found between the two groups. Radiologically, stroma-rich chordomas showed significant signal enhancement on MRI (72.4% vs 27.6%, p = 0.002). Upregulated genes in stroma-rich chordomas were cartilage-, collagen/extracellular matrix-, and tumor metastasis/progression-associated genes. Contrarily, tumor suppressor genes were downregulated in stroma-rich chordomas. On survival analysis, Kaplan–Meier plot was separated that showed inferior outcome of stroma-rich group, although statistically insignificant. In conclusion, the abundant stromal component of conventional chordoma enhanced well on MRI and possibly contributed to the biological aggressiveness that supported by transcriptomic characteristics. Further extensive investigation regarding radiologic-pathologic-transcriptomic correlation in conventional chordoma in a larger cohort could verify additional clinical significance.

Vestibular schwannoma associated with neurofibromatosis type 2: Clinical course following stereotactic radiosurgery

Objective

A lack of understanding of the clinical course of neurofibromatosis type 2 (NF2)-associated vestibular schwannoma (VS) often complicates the decision-making in terms of optimal timing and mode of treatment. We investigated the outcomes of stereotactic radiosurgery (SRS) in this population.

Methods

We retrospectively analyzed NF2 patients treated with Gamma-Knife SRS for VS in our tertiary referral center. A total of 41 treated lesions from 33 patients were collected with a follow-up period of 69.1 (45.0-104.8) months. We reviewed the treatment history, hearing function, and other treatment-related morbidities in individual cases. We also analyzed pre- and post-treatment tumor volumes via imaging studies. Longitudinal volumetric analyses were conducted for the tumor volume response of the 41 treated lesions following SRS. The growth pattern of 22 unirradiated lesions during an observation period of 83.4 (61.1-120.4) months was separately evaluated.

Results

Most treated lesions showed effective tumor control up to 85% at 60 months after SRS, whereas unirradiated lesions progressed with a relative volume increase of 14.0% (7.8-27.0) per year during the observation period. Twelve (29%) cases showed pseudoprogression with significant volume expansion in the early follow-up period, which practically reduced the rate of tumor control to 57% at 24 months. Among the patients with serviceable hearing, two (20%) cases lost the hearing function on the treated side during the early follow-up period within 24 months.

Conclusions

Progressive NF2-associated VS can be adequately controlled by SRS but the short-term effects of this treatment are not highly advantageous in terms of preserving hearing function. SRS treatment candidates should therefore be carefully selected.

Thirty-year clinical experience in gamma knife radiosurgery for trigeminal schwannomas

We aimed to evaluate the radiographic and clinical outcomes after gamma knife radiosurgery (GKRS) for trigeminal schwannomas (TSs). A total of 87 patients who underwent GKRS for TSs between 1990 and 2020 were enrolled. The mean tumor volume was 4.3 cm³. The median prescribed dose for the margins of the tumor was 13 Gy. The median follow-up duration was 64.3 months (range 12.0–311.5 months). The overall local tumor control rate was 90%, and the symptom response rate was 93%. The response rate for each symptom was 88% for facial pain, 97% for facial sensory change, and 86% for cranial nerve deficits. Nineteen (22%) patients showed transient swelling, which had regressed at the time of the last follow-up. Cystic tumors were associated with transient swelling (p = 0.04). A tumor volume of < 2.7 cm³ was associated with local tumor control in univariable analysis. Transient swelling was associated with symptom control failure in both univariable and multivariable analyses (p = 0.04, odds ratio 14.538). GKRS is an effective treatment for TSs, both for local control and symptom control.

Development of 3-dimensional printed simulation surgical training models for endoscopic endonasal and transorbital surgery

Background

Endoscopic skull base surgery (ESBS) is complex, requiring methodical and unremitting surgical training. Herein, we describe the development and evaluation of a novel three-dimensional (3D) printed simulation model for ESBS. We further validate the efficacy of this model as educational support in neurosurgical training.

Methods

A patient-specific 3D printed simulation model using living human imaging data was established and evaluated in a task-based hands-on dissection program. Endoscopic endonasal and transorbital procedures were simulated on the model by neurosurgeons and otorhinolaryngology surgeons of varying experience. All procedures were recorded using a high-definition camera coupled with digital video recorder system. The participants were asked to complete a post-procedure questionnaire to validate the efficacy of the model.

Results

Fourteen experts and 22 trainees participated in simulations, and the 32 participants completed the post-procedure survey. The anatomical realism was scored as 4.0/5.0. The participants rated the model as helpful in hand-eye coordination training (4.7/5.0) and improving surgical skills (4.6/5.0) for ESBS. All participants believed that the model was useful as educational support for trainees (4.7 [ ± 0.5]). However, the color (3.6/5.0) and soft tissue feedback parameters (2.8/5) scored low.

Conclusion

This study shows that high-resolution 3D printed skull base models for ESBS can be generated with high anatomical accuracy and acceptable haptic feedback. The simulation program of ESBS using this model may be supplemental or provide an alternative training platform to cadaveric dissection.

Extended endoscopic transorbital approach with superior-lateral orbital rim osteotomy: cadaveric feasibility study and clinical implications (SevEN-007)

OBJECTIVE

The endoscopic transorbital approach (ETOA) has been developed, permitting a new surgical corridor. Due to the vertical limitation of the ETOA, some lesions of the anterior cranial fossa are difficult to access. The ETOA with superior-lateral orbital rim (SLOR) osteotomy can achieve surgical freedom of vertical as well as horizontal movement. The purpose of this study was to confirm the feasibility of the ETOA with SLOR osteotomy.

METHODS

Anatomical dissections were performed in 5 cadaveric heads with a neuroendoscope and neuronavigation system. ETOA with SLOR osteotomy was performed on one side of the head, and ETOA with lateral orbital rim (LOR) osteotomy was performed on the other side. After analysis of the results of the cadaveric study, the ETOA with SLOR osteotomy was applied in 6 clinical cases.

RESULTS

The horizontal and vertical movement range through ETOA with SLOR osteotomy (43.8° ± 7.49° and 36.1° ± 3.32°, respectively) was improved over ETOA with LOR osteotomy (31.8° ± 5.49° and 23.3° ± 1.34°, respectively) (p < 0.01). Surgical freedom through ETOA with SLOR osteotomy (6025.1 ± 220.1 mm3) was increased relative to ETOA with LOR osteotomy (4191.3 ± 57.2 mm3) (p < 0.01); these values are expressed as the mean ± SD. Access levels of ETOA with SLOR osteotomy were comfortable, including anterior skull base lesion and superior orbital area. The view range of the endoscope for anterior skull base lesions was increased through ETOA with SLOR osteotomy. After SLOR osteotomy, the space for moving surgical instruments and the endoscope was widened. Anterior clinoidectomy could be achieved successfully using ETOA with SLOR osteotomy. The authors performed ETOA with SLOR osteotomy in 6 cases of brain tumor. In all 6 cases, complete removal of the tumor was successfully accomplished. In the 3 cases of anterior clinoidal meningioma, anterior clinoidectomy was performed easily and safely, and manipulation of the extended dural margin and origin dura mater was possible. There was no complication related to this approach.

CONCLUSIONS

The authors evaluated the clinical feasibility of ETOA with SLOR osteotomy based on a cadaveric study. ETOA with SLOR osteotomy could be applied to more diverse disease groups that do not permit conventional ETOA or to cases in which surgical application is challenging. ETOA with SLOR osteotomy might serve as an opportunity to broaden the indication for the ETOA.

Pedicled frontal periosteal rescue flap via eyebrow incision for skull base reconstruction (SevEN-002)

Purpose

Cerebrospinal fluid (CSF) leakage is one of the major complications after endoscopic endonasal surgery. The reconstructive nasoseptal flap is widely used to repair CSF leakage. However, it could not be utilized in all cases; thus, there was a need for an alternative. We developed a pericranial rescue flap that could cover both sellar and anterior skull base defects via the endonasal approach. A modified surgical technique that did not violate the frontal sinus and cause cosmetic problems was designed using the pericranial rescue flap.

Methods

We performed 12 cadaveric dissections to investigate the applicability of the lateral pericranial rescue flap. An incision was made, extending from the middle to the lateral part of the eyebrow. The pericranium layer was dissected away from the galea layer, from the supraorbital region towards the frontoparietal region. With endoscopic assistance, the periosteal flap was raised, the flap base was the pericranium layer at the eyebrow incision. After a burr-hole was made in the supraorbital bone, the pericranial flap was inserted via the intradural or extradural pathway.

Results

The mean size of the pericranial flap was 11.5 cm × 3.2 cm. It was large enough to cross the midline and cover the dural defects of the anterior skull base, including the sellar region.

Conclusion

We demonstrated a modified endoscopic technique to repair the anterior skull base defects. This minimally invasive pericranial flap may resolve neurosurgical complications, such as CSF leakage.

Regrowth factors of WHO grade I skull base meningiomas following incomplete resection

OBJECTIVE

The role of adjuvant radiation therapy following incomplete resection of WHO grade I skull base meningiomas (SBMs) is controversial, and little is known regarding the behavior of residual tumors. The authors investigated the factors that influence regrowth of residual WHO grade I SBMs following incomplete resection.

METHODS

From 2005 to 2019, a total of 710 patients underwent surgery for newly diagnosed WHO grade I SBMs. The data of 115 patients (16.2%) with incomplete resection and without any adjuvant radiotherapy were retrospectively assessed during a mean follow-up of 78 months (range 27-198 months). Pre-, intra-, and postoperative clinical and molecular factors were analyzed for relevance to regrowth-free survival (RFS).

RESULTS

Eighty patients were eligible for analysis, excluding those who were lost to follow-up (n = 10) or had adjuvant radiotherapy (n = 25). Regrowth occurred in 39 patients (48.7%), with a mean RFS of 50 months (range 3-191 months). Significant predictors of regrowth were Ki-67 proliferative index (PI) ≥ 4% (p = 0.017), Simpson resection grades IV and V (p = 0.005), and invasion of the cavernous sinus (p = 0.027) and Meckel's cave (p = 0.027). After Cox regression analysis, only Ki-67 PI ≥ 4% (hazard ratio [HR] 9.39, p = 0.003) and Simpson grades IV and V (HR 8.65, p = 0.001) showed significant deterioration of RFS. When stratified into 4 scoring groups, the mean RFSs were 110, 70, 38, and 9 months for scores 1 (Ki-67 PI < 4% and Simpson grade III), 2 (Ki-67 PI < 4% and Simpson grades IV and V), 3 (Ki-67 PI ≥ 4% and Simpson grade III), and 4 (Ki-67 PI ≥ 4% and Simpson grades IV and V), respectively. RFS was significantly longer for score 1 versus scores 2-4 (p < 0.01). Tumor consistency, histology, location, peritumoral edema, vascular encasement, and telomerase reverse transcriptase promoter mutation had no impact on regrowth.

CONCLUSIONS

Ki-67 PI and Simpson resection grade showed significant associations with RFS for WHO grade I SBMs following incomplete resection. Ki-67 PI and Simpson resection grade could be utilized to stratify the level of risk for regrowth.

Combined petrosal approach for a huge retroclival meningioma preserving the cranial nerves

Surgery for petroclival meningioma is challenging because cranial nerve preservation during tumor removal can be very complex. For small- to medium-sized tumors, the anatomical relationship between tumor and neurovascular structures can be assessed before surgery. However, in large tumors, cranial nerves usually cannot be seen in preoperative images. The authors present a case of a 65-year-old woman who presented with gait disturbance and hearing loss and was diagnosed with huge retroclival meningioma involving the cavernous sinus, Meckel’s cave, and internal acoustic meatus. In this video, they explain the radiographical, anatomical, and surgical considerations and demonstrate the surgical technique.

The video can be found here: https://stream.cadmore.media/r10.3171/2022.1.FOCVID21221

Surgical Outcomes of Sphenoid Wing Meningioma with Periorbital Invasion

Objective

The aim of this study was to evaluate the clinical outcome of sphenoid wing meningioma with periorbital invasion (PI) after operation.

Methods

Sixty one patients with sphenoid wing meningioma were enrolled in this study. Their clinical conditions were monitored after the operation and followed up more than 5 years at the outpatient clinic of a single institution. Clinical and radiologic information of the patients were all recorded including the following parameters : presence of PI, presence of peri-tumor structure invasion, pathologic grade, extents of resection, presence of hyperostosis, exophthalmos index (EI), and surgical complications. We compared the above clinical parameters of the patients with sphenoid wing meningioma in the presence or absence of PI (non-PI), then linked the analyzed data with the clinical outcome of the patients.

Results

Of 61 cases, there were 14 PI and 47 non-PI patients. PI group showed a significantly higher score of EI (1.37±0.24 vs. 1.00±0.01, p<0.001), more frequent presence of hyperostosis (85.7% vs. 14.3%, p<0.001), and lower rate of gross total resection (GTR) (35.7% vs. 68.1%, p=0.032). The lower score of pre-operative EI, the absence of both PI and hyperostosis, smaller tumor size, and the performance of GTR were associated with lower recurrence rates in the univariate analysis. However, in the multivariate analysis, the performance of GTR was the only significant factor to determine the recurrence rate (p=0.043). The incidences of surgical complications were not statistically different between the subtotal resection (STR) and GTR groups, but it was strongly associated tumor size (p=0.017).

Conclusion

The GTR group showed lower recurrence rate than the STR group without differences in the surgical complications. Therefore, the GTR is strongly recommended to treat sphenoid wing meningioma with PI for the better clinical outcome.

Factors Associated With Abducens Nerve Palsy in Patients Undergoing Surgery for Petroclival Meningiomas

BACKGROUND

During the surgical resection of petroclival meningiomas, preserving the cranial nerves is crucial. The abducens nerve is particularly vulnerable during surgery. However, the preoperative risk factors and postoperative prognosis of abducens nerve palsy (ANP) are poorly understood.

METHODS

We retrospectively analyzed 70 patients who underwent surgery for petroclival meningiomas between May 2010 and December 2019, divided into gross-total resection (GTR) and subtotal resection (STR) groups. The relationship of preoperative clinical factors with the incidence and recovery of postoperative ANP was analyzed.

RESULTS

Postoperative ANP was observed in 23 patients (32.9%). Multivariable logistic regression revealed that the tumor-to-cerebellar peduncle T2 imaging intensity index (TCTI) (P < 0.001) and internal auditory canal invasion (P = 0.033) contributed to postoperative ANP. GTR was achieved in 37 patients (52.9%), and 10 (27.0%) of them showed ANP. STR was achieved in 33 patients (47.1%), and 13 (39.4%) of them showed ANP. Recovery from ANP took a median of 6.6 months (range, 4.5-20.3 months). At 6 months after the operation, recovery of the abducens nerve function was observed in 16 patients (69.0%); of whom, 4 (40.0%) were in the GTR group and 12 (92.3%) were in the STR group (P = 0.025).

CONCLUSIONS

TCTI and internal auditory canal invasion were the risk factors for postoperative ANP. Although intentional STR did not prevent ANP immediately after the operation, recovery of the abducens nerve function after surgery was observed more frequently in the STR group than in the GTR group.

Endoscopic Transorbital Approach to Mesial Temporal Lobe for Intra-Axial Lesions: Cadaveric Study and Case Series (SevEN-008)

BACKGROUND

Endoscopic transorbital approach (ETOA) has been proposed as a minimally invasive technique for the treatment of skull base lesions located around mesial temporal lobe (MTL), mostly extra-axial pathology.

OBJECTIVE

To explore the feasibility of ETOA in accessing intraparenchymal MTL with cadaveric specimens and describe our initial clinical experience of ETOA for intra-axial lesions in MTL.

METHODS

Anatomic dissections were performed in 4 adult cadaveric heads using a 0° endoscope. First, a stepwise anatomical investigation of ETOA to intraparenchymal MTL was explored. Then, ETOA was applied clinically for 7 patients with intra-axial lesions in MTL, predominantly high-grade gliomas (HGGs) and low-grade gliomas (LGGs).

RESULTS

The extradural stage of ETOA entailed a superior eyelid incision followed by orbital retraction, drilling of orbital roof, greater and lesser wing of sphenoid bone, and cutting of the meningo-orbital band. For the intradural stage, the brain tissue medial to the occipito-temporal gyrus was aspirated until the temporal horn was opened. The structures of MTL could be aspirated selectively in a subpial manner without injury to the neurovascular structures of the ambient and sylvian cisterns, and the lateral neocortex. After cadaveric validation, ETOA was successfully performed for 4 patients with HGGs and 3 patients with LGGs. Gross total resection was achieved in 6 patients (85.7%) without significant surgical morbidities including visual field deficits.

CONCLUSION

ETOA provides a logical line of access for intra-axial lesions in MTL. The safe and natural surgical trajectory of ETOA can spare brain retraction, neurovascular injury, and disruption of the lateral neocortex.

EPID-13. PREDICTIVE VALUE OF SERUM PROLACTIN LEVEL TO THE TUMOR SIZE RATIO FOR PREOPERATIVE DIAGNOSIS OF PROLACTIN-PRODUCING PITUITARY ADENOMA

PURPOSE

Preoperative diagnosis of prolactinomas is critical because medication of dopamine agonists instead of surgical resection has been regarded as a primary treatment. However, serum prolactin level alone is suboptimal for differentiating the prolactin producing adenoma or hyperprolactinemia-causing NFPAs. The author investigated the use of ratio of PRL levels to the tumor size as the optimal cutoff value for prolactin-producing tumor, comparing with the NFPA.

METHOD

We performed a retrospective review of patients who underwent the transsphenoidal surgery (TSS) for pituitary lesions in the single institute between January 2015 to May 2020. A total of 223 patients with hyperprolactinemia at the initial diagnosis were analyzed in the study, including NFPA patients (n=175) and prolactinoma patients (n=48). Receiver operating curve (ROC) analyses were performed for serum prolactin levels (PRL) and serum prolactin levels/tumor maximal diameter (PRL/MD).

RESULT

Prolactinoma group showed higher median values in serum PRL (258.6 μg/L) and smaller maximal tumor diameter (16.6 mm), compared to those of NFPA group (serum PRL 44.4 μg/L, p-value = 0.002 and MD 23.9 mm, p-value &lt; 0.001). A moderate correlation was found between serum prolactin level and maximal diameters in prolactinomas (r=0.43, p=0.002), whereas a weak relationship was confirmed in NFPAs (r=0.17, p=0.028). The cutoff was 8.93 μg/L*mm (area under the curve [AUC] = 0.94) for PRL/MD and 99.43 μg/L for PRL (AUC = 0.91). In prolactinomas, there was no statistical difference between the PRL/MD of macroadenomas (n=36, 21.7μg/L*mm) and microadenoma (n=12, 16.8μg/L*mm) (p=0.109).

CONCLUSION

The serum PRL levels and tumor size exhibited stronger linear correlation in prolactinomas than in NFPAs. The PRL/MD ratio showed better diagnostic value for differentiating two pathologies than the serum PRL levels alone. These findings suggest PRL/MD ratio may be an alternative method to preoperative diagnosis of prolactinomas differentiating from hyperprolactinemia-causing NFPAs.

A Rare Case of Metastatic Brain Tumor From Classic Biphasic Pulmonary Blastoma Presented as Intracerebral Hemorrhage

Pulmonary blastoma is a rare type of primary lung cancer that accounts for only 0.25%-0.5% of all lung malignancies. Pulmonary blastoma consists of three subgroups: classic biphasic pulmonary blastoma (CBPB), pleuropulmonary blastoma, and well-differentiated fetal adenocarcinoma. Due to the rarity of the tumor, metastatic brain tumor from CBPB is extremely rare, and only 13 cases, including our case, have been reported. A 60-year-old woman who underwent left upper lobectomy of the lung because of pathologically diagnosed as CBPB 5 months ago, suddenly lost consciousness and presented with stupor mental status. The emergent CT scan showed a large, 51 mL, intracerebral hemorrhage on left parieto-occipital lobe with midline shifting. The patient underwent emergent craniotomy, and a hypervascular tumor was identified during the operation. Histopathologic examination reported metastatic pulmonary blastoma, CBPB. The patient has been in a vegetative state, but there has been no evidence of recurrence over a 6-month follow-up period. We report a rare case of brain metastasis from CBPB presenting with altered mentality due to massive tumor bleeding. This is the only reported case of brain metastasis from CBPB presenting with acute intracerebral hemorrhage.

Clinical applications of the endoscopic transorbital approach for various lesions

BACKGROUND

The endoscopic transorbital approach (ETOA) was recently added to the neurosurgical armamentarium. Although this approach could result in less injury to normal brain tissue, shorter operation times, and smaller scars, its clinical applications have not been fully investigated. We, therefore, sought to share our unique experiences of exploring the application of this approach in various diseases.

METHODS

From June 2017 to March 2019, we conducted ETOAs via the superior eyelid crease in 22 patients for the treatment of lesions confined to the middle fossa with and without slight extension to the posterior fossa. These lesions included 5 gliomas, 11 meningiomas, 3 schwannomas, 1 lymphoma, 1 cavernous hemangioma in the orbital wall, and 1 hemangiopericytoma mimicking schwannoma. Perioperative radiologic findings and clinical outcomes were recorded.

RESULTS

Gross total resection was accomplished in three (60%) patients with gliomas, nine (81.8%) with meningiomas, two (66.7%) with schwannomas, and one (33.3%) with another lesion. The mean bleeding count was 1051.4 ± 961.1 cc, and major complications were observed in only two (9.1%) cases (one major cerebral artery infarction and one reoperation due to a large amount of bleeding). A cerebrospinal fluid leak was reported in two (9.1%) patients, and transient eye movement palsy was noted in four (18.2%) patients without permanent disability.

CONCLUSIONS

The endoscopic transorbital approach could be considered to be feasible for various lesions with different characteristics. After carefully considering the lesion anatomy, consistency, and vascular relationships, using this approach, we could achieve a satisfactory extent of resection without severe complications.

Virtual dissection of the real brain: integration of photographic 3D models into virtual reality and its effect on neurosurgical resident education

OBJECTIVE

Virtual reality (VR) is increasingly being used for education and surgical simulation in neurosurgery. So far, the 3D sources for VR simulation have been derived from medical images, which lack real color. The authors made photographic 3D models from dissected cadavers and integrated them into the VR platform. This study aimed to introduce a method of developing a photograph-integrated VR and to evaluate the educational effect of these models.

METHODS

A silicone-injected cadaver head was prepared. A CT scan of the specimen was taken, and the soft tissue and skull were segmented to 3D objects. The cadaver was dissected layer by layer, and each layer was 3D scanned by a photogrammetric method. The objects were imported to a free VR application and layered. Using the head-mounted display and controllers, the various neurosurgical approaches were demonstrated to neurosurgical residents. After performing hands-on virtual surgery with photographic 3D models, a feedback survey was collected from 31 participants.

RESULTS

Photographic 3D models were seamlessly integrated into the VR platform. Various skull base approaches were successfully performed with photograph-integrated VR. During virtual dissection, the landmark anatomical structures were identified based on their color and shape. Respondents rated a higher score for photographic 3D models than for conventional 3D models (4.3 ± 0.8 vs 3.2 ± 1.1, respectively; p = 0.001). They responded that performing virtual surgery with photographic 3D models would help to improve their surgical skills and to develop and study new surgical approaches.

CONCLUSIONS

The authors introduced photographic 3D models to the virtual surgery platform for the first time. Integrating photographs with the 3D model and layering technique enhanced the educational effect of the 3D models. In the future, as computer technology advances, more realistic simulations will be possible.

Differences in surgical outcome between petroclival meningioma and anterior petrous meningioma

BACKGROUND

Petroclival meningiomas (PC MNGs) and anterior petrous meningiomas (AP MNGs) have similar locations. However, these are different tumors clearly divided by the trigeminal nerve. There has never been a study on the comparison of the surgical outcomes of these two meningiomas. In this study, we compared and analyzed the surgical outcome of PC MNGs and AP MNGs.

METHODS

The charts of 85 patients diagnosed with PC MNGs of AP MNGs who underwent surgical treatment were retrospectively reviewed. And we analyzed the characteristics of 49 PC MNGs (57.6%) and compared them with those of 36 AP MNGs.

RESULTS

Preoperative brainstem edema was observed in 11 patients (22.4%) of the PC MNG group and 1 patient (2.8%) of the AP MNG group (p = 0.024). Total tumor removal was achieved in 21 patients (58.3%) of the AP MNG group, but only 17 patients (34.7%) of the PC MNG group were able to completely (p = 0.047). In addition, sixth cranial nerve palsy occurred in 17 patients (34.7%) of the PC MNG group and 4 patients (11.1%) of the AP MNG group (p = 0.025).

CONCLUSIONS

In this study, we found that PC MNGs has a worse surgical outcome than AP MNGs, because PC MNGs were difficult to completely remove and were more likely to damage abducens nerve.

The behavior of residual tumors following incomplete surgical resection for vestibular schwannomas

The management of vestibular schwannoma (VS) with residual tumor following incomplete resection remains controversial and little is known regarding postoperative tumor volume changes. The behavior of residual tumors was analyzed for 111 patients who underwent surgery for newly diagnosed VS between September 2006 and July 2017. The postoperative tumor volume changes were assessed during a mean follow-up of 69 months (range 36–147 months). Fifty-three patients underwent imaging surveillance following incomplete resection. There was no residual tumor growth in 44 patients (83%). A significant regression of residual tumor volume was noted in the no growth group at postoperative 1 year (p = 0.028), 2 years (p = 0.012), but not from 3 years onwards. Significant predictors of regrowth were immediate postoperative tumor volume ≥ 0.7 cm³ (HR 10.5, p = 0.020) and residual tumor location other than the internal auditory canal (IAC) (HR 6.2, p = 0.026). The mean time to regrowth was 33 months (range 5–127 months). The 2-, 5-, and 10-year regrowth-free survival rates were 90.6%, 86.8%, and 83%, respectively. In conclusion, significant residual tumor regression could occur within 2 years for a VS with an immediate postoperative tumor volume less than 0.7 cm³ or residual tumor in IAC.

Optimization of orbital retraction during endoscopic transorbital approach via quantitative measurement of the intraocular pressure - [SevEN 006]

Background

Increased use of the transorbital approach (TOA) warrants greater understanding of the risk of increased intraocular pressure (IOP) and intraorbital pressure (IORP) due to orbital compression. We aimed to investigate the changes in IOP and IORP in response to orbital retraction in TOA and establish a method for the continuous measurement of intraoperative IORP.

Methods

We assessed nine patients who underwent TOA surgery from January 2017 to December 2019, in addition to five cadavers. IORP and IOP were measured using a cannula needle monitor, tonometer, cuff manometer, and micro strain gauge monitor.

Results

In all nine clinical cases and five cadavers, increased physical compression of the orbit increased the IOP and IORP in a curvilinear pattern. In clinical cases, when the orbit was compressed 1.5 cm from the lateral margin in the sagittal plane, the mean IOP and IORP were 25.4 ± 5.2 mmHg and 14 ± 9.2 mmH₂O, respectively. The IORP satisfactorily reflected the IOP (Pearson correlation coefficient = 0.824, p < 0.001).

Conclusion

We measured IOP and IORP simultaneously during orbital compression to gain basic information on pressure changes. In clinical cases, the change in the IOP could be conveniently and noninvasively monitored using continuous IORP measurements.

Anterior skull base reconstruction using nasoseptal flap: cadaveric feasibility study and clinical implication [SevEN-001]

BACKGROUND

Pedicled nasoseptal flap (PNSF) has significantly improved the surgical outcomes of endoscopic endonasal approach (EEAs) by reducing cerebrospinal fluid (CSF) leakage. The purpose of this study is to assess the feasibility of using a PNSF for anterior skull base (ASB) reconstruction and to describe a method to compensate for a short flap based on our results.

METHODS

In this cadaveric study, ASB dissection without sphenoidotomy was performed using 10 formalin-fixed and 5 fresh adult cadaver specimens, and the sufficiency of the PNSF to cover the ASB was assessed. After the sphenoidotomy, the length by which the PNSF fell short in providing coverage at the posterior wall of the frontal sinus (CPFS), and the extent of the anterior coverage from the limbus (CL) of the sphenoid bone was measured.

RESULTS

Without sphenoidotomy, the mean length of the remaining PNSF after the coverage of the posterior wall of the frontal sinus was 0.67 cm. After sphenoidotomy, the PNSF fell short by a mean length of 2.10 cm, in providing CPFS. The CL was 1.86 cm. Based on these findings, defects resulting from an endoscopic resection of ASB tumors were reconstructed using PNSF without total sphenoidotomy in 3 patients. There were no postoperative CSF leaks or complications.

CONCLUSIONS

The use of PNSF for ASB reconstruction may be insufficient to cover the entire ASB defect after removal of large lesions which need total sphenoidotomy. When possible, by leaving some portion of the anterior sphenoid wall for supporting the PNSF, successful ASB reconstruction could be achieved in endoscopic resection of ASB tumors. Additional methods might be needed in some cases of large ASB lesions wherein the anterior sphenoid wall should be removed totally and the ASB defect is too large.

Biportal endoscopic transorbital approach: a quantitative anatomical study and clinical application

BACKGROUND

We devised a biportal endoscopic transorbital approach (BiETOA) to gain surgical freedom by making a port for the endoscope and investigated the benefits and limitations of BiETOA.

METHODS

A cylindrical port was designed and 3-D printed using biocompatible material. The port was inserted through a keyhole between the superolateral side of the orbital rim and the temporal muscle. An endoscope was inserted through the port, and other instruments were inserted through the conventional transorbital route. BiETOA was used to dissect eight cadaveric heads, and the angle of attack and surgical freedom were assessed.

RESULTS

The mean maximal angle of attack was significantly different in BiETOA and endoscopic transorbital approach (ETOA) (P < 0.01) but not in BiETOA and ETOA lateral orbital rim (LOR) osteotomy (P = 0.207, P = 0.21). The mean surgical freedom was significantly different in BiETOA and ETOA (P < 0.01) and in BiETOA and ETOA LOR osteotomy (P < 0.01). In the clinical cases, tumors were removed successfully without any complications.

CONCLUSIONS

BiETOA provided increased surgical freedom and better visibility of deep target lesion and resulted in good surgical and cosmetic outcomes.

Endoscopic transorbital and endonasal approach for trigeminal schwannomas: a retrospective multicenter analysis (KOSEN-005)

OBJECTIVE

Trigeminal schwannomas are rare neoplasms with an incidence of less than 1% that require a comprehensive surgical strategy. These tumors can occur anywhere along the path of the trigeminal nerve, capable of extending intradurally into the middle and posterior fossae, and extracranially into the orbital, pterygopalatine, and infratemporal fossa. Recent advancements in endoscopic surgery have suggested a more minimally invasive and direct route for tumors in and around Meckel's cave, including the endoscopic endonasal approach (EEA) and endoscopic transorbital superior eyelid approach (ETOA). The authors assess the feasibility and outcomes of EEA and ETOA for trigeminal schwannomas.

METHODS

A retrospective multicenter analysis was performed on 25 patients who underwent endoscopic surgical treatment for trigeminal schwannomas between September 2011 and February 2019. Thirteen patients (52%) underwent EEA and 12 (48%) had ETOA, one of whom underwent a combined approach with retrosigmoid craniotomy. The extent of resection, clinical outcome, and surgical morbidity were analyzed to evaluate the feasibility and selection of surgical approach between EEA and ETOA based on predominant location of trigeminal schwannomas.

RESULTS

According to predominant tumor location, 9 patients (36%) had middle fossa tumors (Samii type A), 8 patients (32%) had dumbbell-shaped tumors located in the middle and posterior cranial fossae (Samii type C), and another 8 patients (32%) had extracranial tumors (Samii type D). Gross-total resection (GTR, n = 12) and near-total resection (NTR, n = 7) were achieved in 19 patients (76%). The GTR/NTR rates were 81.8% for ETOA and 69.2% for EEA. The GTR/NTR rates of ETOA and EEA according to the classifications were 100% and 50% for tumors confined to the middle cranial fossa, 75% and 33% for dumbbell-shaped tumors located in the middle and posterior cranial fossae, and 50% and 100% for extracranial tumors. There were no postoperative CSF leaks. The most common preoperative symptom was trigeminal sensory dysfunction, which improved in 15 of 21 patients (71.4%). Three patients experienced new postoperative complications such as vasospasm (n = 1), wound infection (n = 1), and medial gaze palsy (n = 1).

CONCLUSIONS

ETOA provides adequate access and resectability for trigeminal schwannomas limited in the middle fossa or dumbbell-shaped tumors located in the middle and posterior fossae, as does EEA for extracranial tumors. Tumors predominantly involving the posterior fossa still remain a challenge in endoscopic surgery.

Radiosurgery vs. microsurgery for newly diagnosed, small petroclival meningiomas with trigeminal neuralgia

Trigeminal neuralgia (TN) is an excruciating pain that can occur with petroclival meningiomas (PCMs). Gamma knife radiosurgery (GKRS) is an appealing option for small PCMs, but the role of microsurgery (MS) compared to GKRS is not well defined for small PCMs with regard to TN relief. From January 2009 to September 2019, 70 consecutive patients were treated by GKRS or MS for newly diagnosed, small (< 3.5 cm) PCMs with TN. GKRS or MS were performed for 35 patients each. The surgical outcome and TN control according to Barrow Neurological Institute (BNI) score were retrospectively analyzed and compared between GKRS and MS. The predominant origin of PCMs was upper clival (49%) with trigeminal nerve compression at the medial dorsal root entry zone. Tumor control rates were equally 94% with GKRS or MS for a mean tumor size and volume of 2.3 cm and 5.3 cm³, respectively. The preoperative BNI scores were mostly II (40%) and IV (37%) with GKRS and MS, respectively. TN relief without medications (BNI scores I and II) was achieved in 13 of 35 patients (37%) with GKRS and 32 of 35 patients (91%) with MS during a mean follow-up of 50.5 months. The most common complications after GKRS and MS were dysesthesia (23%) and diplopia (9%), respectively. MS could be more effective than GKRS in providing prompt, medication-free pain relief from TN for small PCMs. The risks of MS have to be considered carefully in experienced hands, especially for small PCMs.

Association between survival and levetiracetam use in glioblastoma patients treated with temozolomide chemoradiotherapy

This study was conducted to assess whether levetiracetam (LEV) affects the survival of patients with glioblastoma (GBM) treated with concurrent temozolomide (TMZ) chemotherapy. To this end, from 2004 to 2016, 322 patients with surgically resected and pathologically confirmed isocitrate dehydrogenase (IDH)-wildtype GBM who received TMZ-based chemoradiotherapy were analysed. The patients were divided into two groups based on whether LEV was used as an anticonvulsant both at the time of surgery and the first visit thereafter. The median overall survival (OS) and progression-free survival (PFS) were compared between the groups. The OS was 21.1 and 17.5 months in the LEV (+) and LEV (−) groups, respectively (P = 0.003); the corresponding PFS was 12.3 and 11.2 months (P = 0.017). The other prognostic factors included age, extent of resection, O⁶-methylguanine-DNA methyltransferase (MGMT) promoter methylation status, and Karnofsky Performance Status (KPS) score. The multivariate analysis showed age (hazard ratio [HR], 1.02; P < 0.001), postoperative KPS score (HR 0.99; P = 0.002), complete tumour resection (HR 0.52; P < 0.001), MGMT promoter methylation (HR 0.75; P < 0.001), and LEV use (HR 0.72; P = 0.011) were significantly associated with OS. In conclusion, LEV use was associated with prolonged survival in patients with GBM treated with concurrent TMZ chemoradiotherapy.

Optimal indications and limitations of endoscopic transorbital superior eyelid surgery for spheno-orbital meningiomas

OBJECTIVE

Spheno-orbital meningiomas (SOMs) are complicated tumors that involve multiple structures at initial presentation, such as the orbit, temporalis muscle, sphenoidal bone, cavernous sinus, and temporal or infratemporal fossa. The infiltrative growth and complexity of this type of meningioma make total resection impossible. In this study, the authors evaluated the surgical outcome of the endoscopic transorbital approach (eTOA) for SOM. In addition, they identified optimal indications for the use of eTOA and analyzed the feasibility of this approach as a minimally invasive surgery for SOMs of varying types and locations at presentation.

METHODS

Between September 2016 and December 2019, the authors performed eTOA in 41 patients with SOM with or without orbital involvement at 3 independent tertiary institutions. The authors evaluated the surgical outcomes of eTOA for SOM and investigated several factors that affect the outcome, such as tumor volume, tumor location, and the presence of lateral orbitotomy. Gross-total resection (GTR) was defined as complete resection of the tumor or intended subtotal resection except the cavernous sinus. This study was undertaken as a multicenter project (006) of the Korean Society of Endoscopic Neurosurgery (KOSEN-006).

RESULTS

There were 41 patients (5 men and 36 women) with a median age of 52.0 years (range 24-73 years). Twenty-one patients had tumors that involved the orbital structure, while 14 patients had tumors that presented at the sphenoidal bone along with other structures, such as the cavernous sinus, temporal fossa, and infratemporal fossa. Fifteen patients had the globulous type of tumor and 26 patients had the en plaque type. Overall, GTR was achieved in 21 of 41 patients (51.2%), and complications included CSF leaks in 2 patients and wound complications in 2 patients. Multiple logistic regression analysis showed that the en plaque type of tumor, absence of lateral orbital rim osteotomy, involvement of the temporal floor or infratemporal fossa, and involvement of the orbit and medial one-third of the greater sphenoidal wing were closely associated with lower GTR rates (p < 0.05). Multivariate analysis revealed that the en plaque type of tumor and the absence of lateral orbital rim osteotomy were significant predictors for lower GTR rate.

CONCLUSIONS

The en plaque type of SOM remains a challenge despite advances in technique such as minimally invasive surgery. Overall, clinical outcome of eTOA for SOM was comparable to the transcranial surgery. To achieve GTR, eTOA is recommended, with additional lateral orbital rim osteotomy for globulous-type tumors, without involving the floor of the temporal and infratemporal fossa.

Comparative Analysis of Endoscopic Transorbital Approach and Extended Mini-Pterional Approach for Sphenoid Wing Meningiomas with Osseous Involvement: Preliminary Surgical Results

OBJECTIVE

Sphenoid wing meningiomas (SWMs) can be treated with complete surgical resection and the recently introduced endoscopic transorbital approach (ETOA) offers a minimally invasive alternative. In this study, the surgical outcome of ETOA and the extended mini-pterional approach (eMPTA) for SWMs with osseous involvement is compared.

METHODS

From October 2015 to May 2019, 24 patients underwent surgery for SWMs with osseous involvement. Among them, tumor resection was performed by ETOA for 11 patients (45.8%) and eMPTA for 13 patients (54.2%). The tumor characteristics, surgical outcome and morbidity, and approach-related aesthetic outcome were analyzed and compared retrospectively between ETOA and eMPTA based on SWM classification.

RESULTS

The location of SWMs was mostly the middle sphenoid ridge (group III) (45.8%), followed by the greater sphenoid wing (group IV) (29.2%). Simpson resection grades I/II were achieved in 9 of 11 patients (81.8%) with ETOA and 11 of 13 patients (84.6%) with eMPTA. There were no differences in tumor characteristics between the 2 approaches. Surgery time, surgical bleeding, and hospital length of stay were significantly shorter with ETOA. Three patients had transient surgical morbidities such as diplopia (n = 1), ptosis (n = 1), and cerebrospinal fluid leak (n = 1) after ETOA. No differences could be seen in surgical morbidities between ETOA and eMPTA.

CONCLUSIONS

ETOA can provide direct access to the sphenoid bone and resectability with a more rapid and minimally invasive exposure than does eMPTA. Maximal subtotal resection with extensive sphenoid bone decompression for tumors with cavernous sinus infiltration is the key to a good clinical outcome, regardless of the surgical approach.

Rete middle cerebral artery anomalies: a unifying name, case series, and literature review

OBJECTIVE

Rete middle cerebral artery (MCA) is extremely rare and has not been frequently discussed. Rete MCA is a weblike anomaly of the MCA that does not coalesce and forms a prominent, large single branch from the plexiform vessels in the fetal stage. The purpose of this study was to further elucidate the clinical and radiological characteristics of patients with rete MCA.

METHODS

A total of 2262 cerebral digital subtraction angiography procedures were performed on 1937 patients at the authors' institution from February 2013 to May 2017. Data analysis included age, sex, clinical symptoms, underlying diseases, coexisting cerebral arterial anomalies, and operative methods and findings.

RESULTS

Rete MCAs were found in 13 patients, and the incidence of this anomaly was 0.67% (13 of 1937) in this study. Of the 13 patients, 3 had hemorrhagic strokes, 6 had ischemic strokes, and 4 had no symptoms. Eight patients underwent conservative treatment, and 5 patients underwent surgical treatment. Rete MCA is considered a congenital disease of the cerebral vasculature with the possibility of an acquired abnormality, such as an aneurysm, caused by hemodynamic stress. Although an epidemiological survey of rete MCA was not conducted, it is assumed that rete MCA has a high prevalence in Asia. Ischemic and hemorrhagic stroke events are fairly common in rete MCA.

CONCLUSIONS

Clinicians should understand the radiological and clinical features of patients with rete MCA to avoid misdiagnosis and unnecessary treatment. This anomaly should be differentiated from other vascular diseases and patients presenting incidentally should be carefully monitored because of their vulnerability to both hemorrhagic and ischemic strokes.

Clinical and ophthalmological outcome of endoscopic transorbital surgery for cranioorbital tumors

OBJECTIVE

Cranioorbital tumors are complex lesions that involve the deep orbit, floor of the frontal bone, and lesser and greater wing of the sphenoid bone. The purpose of this study was to describe the clinical and ophthalmological outcomes with an endoscopic transorbital approach (TOA) in the management of cranioorbital tumors involving the deep orbit and intracranial compartment.

METHODS

The authors performed endoscopic TOAs via the superior eyelid crease incision in 18 patients (16 TOA alone and 2 TOA combined with a simultaneous endonasal endoscopic resection) with cranioorbital tumors from September 2016 to November 2017. There were 12 patients with sphenoorbital meningiomas. Other lesions included osteosarcoma, plasmacytoma, sebaceous gland carcinoma, intraconal schwannoma, cystic teratoma, and fibrous dysplasia. Ten patients had primary lesions and 8 patients had recurrent tumors. Thirteen patients had intradural lesions, while 5 had only extradural lesions.

RESULTS

Of 18 patients, 7 patients underwent gross-total resection of the tumor and 7 patients underwent planned near-total resection of the tumor, leaving the cavernous sinus lesion. Subtotal resection was performed in 4 patients with recurrent tumors. There was no postoperative CSF leak requiring reconstruction surgery. Fourteen of 18 patients (77.8%) had preoperative proptosis on the ipsilateral side, and all 14 patients had improvement in exophthalmos; the mean proptosis reduced from 5.7 ± 2.7 mm to 1.5 ± 1.4 mm. However, some residual proptosis was evident in 9 of the 14 (64%). Ten of 18 patients (55.6%) had preoperative optic neuropathy, and 6 of them (60.0%) had improvement; the median best-corrected visual acuity improved from 20/100 to 20/40. Thirteen of 18 patients showed mild ptosis at an immediate postoperative examination, all of whom had a spontaneous and complete recovery of their ptosis during the follow-up period. Three of 7 patients showed improvement in extraocular motility after surgery.

CONCLUSIONS

Endoscopic TOA can be considered as an option in the management of cranioorbital tumors involving complex anatomical areas, with acceptable sequelae and morbidity.

Real-Time Noninvasive Intracranial State Estimation Using Unscented Kalman Filter

Intracranial pressure (ICP) monitoring is desirable as a first-line measure to assist decision-making in cases of increased ICP. Clinically, non-invasive ICP monitoring is also required to avoid infection and hemorrhage in patients. The relationships among the arterial blood pressure (ABP), ICP, cerebral blood flow, and its velocity ( [Formula: see text]) measured by transcranial Doppler ultrasound measurement have been reported. However, real-time non-invasive ICP estimation using these modalities is less well documented. This paper presents a novel algorithm for real-time and non-invasive ICP monitoring with [Formula: see text] and ABP, called direct-current (DC)-ICP. The technique was compared with invasive ICP for 10 acute-brain-injury patients admitted to Cheju Halla Hospital and Gangnam Severance Hospital from July 2017 to June 2018. The inter-subject correlation coefficient between true and estimate was 0.75 and the AUCs of the ROCs for prediction of increased ICP for the DC-ICP methods were 0.83. Thus, [Formula: see text] monitoring can facilitate reliable real-time ICP tracking with our novel DC-ICP algorithm, which can provide valuable information under clinical conditions.

In vitro and in vivo experiments of a novel intra-arterial neurovascular decompressor for treating neurovascular compression syndromes: a brief report

Objectives: Neurovascular compression syndromes (NVCS) could be cured with an intravascular device that releases compression of the root entry zone of cranial nerves by changing the course of offending vessels. The purpose of this study was to report our results of in vitro and in vivo experiments with a novel intra-arterial neurovascular decompressor (IA-NVD) for NVCS. Methods: A nitinol-based IA-NVD was developed to release pressure applied to the root entry zone of cranial nerves by changing the course or angle of an offending vessel, which can possibly cure NVCS. We performed in vitro tests for safety and feasibility and preliminary in vivo tests up to 4 weeks for safety. Results: The bending stiffness of the device was similar to but slightly stronger than that of current, closed-cell intracranial stents. Hemocompatibility tests showed no significant thrombogenesis in whole blood. After the 4-week follow-up, all animals (20-month-old female Gottingen mini-pigs weighing 15-18 kg, n = 4) had a normal upright position and gait. Scanning electron microscopy images and H&E staining of arteries containing the devices showed good neointima formation on the devices. Intima hyperplasia occurred over wires and connecting tubes, but it did not interrupt the patency of the arterial lumen. Discussion: An IA-NVD was created and tested to demonstrate its functionality and biocompatibility in the present experiments. The device may be safely applied to intracranial arteries, providing us a chance to test the efficacy of an upgrade version of the device on changing the course of an artery that compresses a cranial nerve. Abbreviations: CN = cranial nerve; EVT = endovascular treatment; H&E = hematoxylin and eosin; HFS = hemifacial spasm; IA-NVD = intra-arterial neurovascular decompressor; MVD = microvascular decompression; NVCS = neurovascular compression syndrome; REZ = root entry zone; SEM = scanning electron microscopy; TN = trigeminal neuralgia.

Survival benefit of lobectomy over gross-total resection without lobectomy in cases of glioblastoma in the noneloquent area: a retrospective study

OBJECTIVE

Following resection of glioblastoma (GBM), microscopic remnants of the GBM tumor remaining in nearby tissue cause tumor recurrence more often than for other types of tumors, even after gross-total resection (GTR). Although surgical oncologists traditionally resect some of the surrounding normal tissue, whether further removal of nearby tissue may improve survival in GBM patients is unknown. In this single-center retrospective study, the authors assessed whether lobectomy confers a survival benefit over GTR without lobectomy when treating GBMs in the noneloquent area.

METHODS

The authors selected 40 patients who had undergone GTR of a histopathologically diagnosed isocitrate dehydrogenase (IDH)-wild type GBM in the right frontal or temporal lobe and divided the patients into 2 groups according to whether GTR of the tumor involved lobectomy, defined as a supratotal resection (SupTR group, n = 20) or did not (GTR group, n = 20). Progression-free survival (PFS), overall survival (OS), and Karnofsky Performance Status (KPS) scores were compared between groups (p ≤ 0.05 for statistically significant differences).

RESULTS

The median postoperative PFS times for each group were as follows: GTR group, 11.5 months (95% CI 8.8-14.2) and SupTR group, 30.7 months (95% CI 4.3-57.1; p = 0.007). The median postoperative OS times for each group were as follows: GTR group, 18.7 months (95% CI 14.3-23.1) and SupTR group, 44.1 months (95% CI 25.1-63.1; p = 0.040). The mean postoperative KPS scores (GTR, 76.5; SupTR, 77.5; p = 0.904) were not significantly different. In multivariate analysis, survival for the SupTR group was significantly longer than that for the GTR group in terms of both PFS (HR 0.230; 95% CI 0.090-0.583; p = 0.002) and OS (HR 0.247; 95% CI 0.086-0.704; p = 0.009).

CONCLUSIONS

In cases of completely resectable, noneloquent-area GBMs, SupTR provides superior PFS and OS without negatively impacting patient performance.

Endoscopic transorbital surgery for Meckel's cave and middle cranial fossa tumors: surgical technique and early results

OBJECTIVE

Tumors involving Meckel's cave remain extremely challenging because of the surrounding complex neurovascular structures and deep-seated location. The authors investigated a new minimal-access technique using the endoscopic transorbital approach (eTOA) through the superior eyelid crease to Meckel's cave and middle cranial fossa lesions and reviewed the most useful surgical procedures and pitfalls of this approach.

METHODS

Between September 2016 and January 2018, the authors performed eTOA in 9 patients with tumors involving Meckel's cave and the middle cranial fossa. The lesions included trigeminal schwannoma in 4 patients, meningioma in 2 patients, metastatic brain tumor in 1 patient, chondrosarcoma in 1 patient, and dermoid cyst in 1 patient. In 7 of the 9 patients, eTOA alone was performed, while the other 2 patients underwent a combined eTOA and endoscopic endonasal approach or retrosigmoid craniotomy. Data including details of surgical techniques and clinical outcomes were recorded.

RESULTS

Gross-total resection was performed in 7 of the 9 patients (77.8%). Four patients underwent extended eTOA (with lateral orbital rim osteotomy). Drilling of the trapezoid sphenoid floor, a middle fossa "peeling" technique, and full visualization of Meckel's cave were applied to approach the lesions. Tumors were exposed and removed extradurally in 3 patients and intradurally in 6 patients. There was no postoperative CSF leak.

CONCLUSIONS

The eTOA affords a direct route to access Meckel's cave and middle cranial fossa lesions. With experience, this novel approach can be successfully applied to selected skull base lesions. To achieve successful removal of the tumor, emphasis should be placed on the importance of adequately removing the greater sphenoid wing and vertical crest. However, because of limited working space eTOA may not be an ideal approach for posterior fossa lesions.

The timing of fusion surgery for clival chordoma with occipito-cervical joint instability: before or after tumor resection?

Clival chordoma with occipito-cervical (OC) joint invasion can result in preoperative and postoperative instability. The authors investigate the appropriate timing of OC fusion to prevent instability-, fusion-, and surgery time-related morbidity. Twenty-two consecutive patients underwent surgery for clival chordoma from December 2008 to September 2014. OC fusion was performed for patients with OC joint invasion and instability due to preoperative destruction of the occipital condyle or extensive postoperative condylectomy. The data in relation to OC joint instability, fusion, and surgery time were analyzed retrospectively and compared between OC fusion before and after tumor resection. Of the 22 patients, 8 with tumor invasion of the OC joint underwent OC fusion. OC fusion was performed after tumor resection in one-stage for four patients and before tumor resection in two-stage for four patients. There was OC joint instability from tumor destruction of the occipital condyle in seven patients (87.5%). Patients with OC fusion after tumor resection encountered complications such as surgery site wound dehiscence, encephalitis, and cardiac arrest with consequent mortality in one patient. These complications were avoided in subsequent patients where OC fusion was performed before tumor resection. There were no differences in the extent of tumor resection between OC fusion before and after tumor resection. Two-stage OC fusion before tumor resection can reduce instability-, fusion-, and surgery time-related morbidity and achieve feasible tumor resection when OC joint instability is expected. The extent of tumor invasion and brain stem compression should be considered when fusion precedes tumor resection.

Radiographic and microsurgical characteristics of proximal (A1) segment aneurysms of the anterior cerebral artery

BACKGROUND

Proximal A1 segment aneurysms of the anterior cerebral artery (ACA) radiologically resemble internal carotid artery bifurcation (ICBIF) aneurysms because of their anatomical proximity. However, proximal A1 aneurysms exhibit distinguishing features, relative to ICBIF aneurysms. We report our experience of managing proximal A1 aneurysms, then compare them to ICBIF aneurysms.

METHODS

Among 2191 aneurysms treated between 2000 and 2016 in a single institution, we retrospectively reviewed 100 cases categorized as ICBIF or A1 aneurysms. We included aneurysms originating from the ICBIF and ACA, proximal to the anterior communicating artery (A1 segment) and divided them into two groups: proximal A1 (n = 32) and ICBIF (n = 50). If any portion of the aneurysm involved the ICBIF, it was classified as ICBIF. Aneurysms wholly located in the A1 segment were classified as proximal A1. Patient factors and angiographic factors were evaluated and compared.

RESULTS

The proximal A1 group exhibited differences in aneurysm size (p = 0.013), posterior aneurysm direction (p = 0.001), and A1 perforators as incorporating vessels (p = 0.001). The proximal A1 group tended to rupture more frequently when the aneurysm was smaller (p = 0.046). One case of morbidity occurred in the proximal A1 group.

CONCLUSION

Compared to ICBIF aneurysms, proximal A1 aneurysms were smaller and directed posteriorly, with incorporating perforators. Because of these characteristics, it may be difficult to perform clipping with 360° view in microsurgical field. Therefore, when planning to treat proximal A1 aneurysms, different treatment strategies may be necessary, relative to those used for ICBIF aneurysms.

Selection of endoscopic or transcranial surgery for tuberculum sellae meningiomas according to specific anatomical features: a retrospective multicenter analysis (KOSEN-002)

OBJECTIVE

The endoscopic endonasal approach (EEA) and the transcranial approach (TCA) are good options for the treatment of tuberculum sellae (TS) meningiomas. The objective of this study was to identify the key anatomical features in TS meningiomas and compare the two surgical approaches.

METHODS

The authors retrospectively reviewed clinical data in 178 patients with TS meningiomas treated at 3 institutions between January 2010 and July 2016. Patients with tumors encasing the internal carotid artery or anterior cerebral artery or involving the anterior clinoid process or cavernous sinus were excluded. Tumors were classified as high-lying or low-lying based on their location, and involvement of the optic canal was evaluated. The surgical outcomes of EEA and TCA were analyzed according to the relevant anatomical features.

RESULTS

During the study period, 84 patients underwent EEA and 94 patients underwent TCA. Based on preoperative MR images, 43 (24.2%) meningiomas were classified as high-lying tumors, 126 (70.8%) as low-lying, and 9 (5.0%) as nonspecific. Gross-total resection (GTR) was performed in 145 patients (81.5%); the GTR rate did not differ significantly between the EEA and TCA groups. Of 157 patients with preoperative visual disturbance, 140 had improved or stable vision postoperatively. However, 17 patients (9.6%) experienced some visual deterioration after surgery. The TCA group had a worse visual outcome than the EEA group in patients with preoperative optic canal involvement (77.6% vs 93.2%, p = 0.019), whereas there was no significant difference in visual outcome based on whether tumors were high-lying or low-lying.

CONCLUSIONS

The results of this study support EEA over TCA, at least with respect to visual improvement with acceptable complications, although TCA is still an effective approach for TS meningioma.

Multi-institutional study of treatment patterns in Korean patients with WHO grade II gliomas: KNOG 15-02 and KROG 16-04 intergroup study

INTRODUCTION

We performed this study to identify the treatment patterns of patients with low-grade gliomas (LGG) in Korea.

METHODS

A total of 555 patients diagnosed as WHO grade II gliomas between 2000 and 2010 at 14 Korean institutions were included. The patients were divided into four adjuvant treatment groups: adjuvant fractionated radiotherapy (RT, N = 204), adjuvant chemotherapy (N = 20), adjuvant fractionated RT and chemotherapy (N = 65), and non-adjuvant treatment (N = 266) groups. We examined differences among the groups and validated patient/tumor characteristics associated with the adjuvant treatments.

RESULTS

Astrocytoma was diagnosed in 210 patients (38%), oligoastrocytoma in 85 patients (15%), and oligodendroglioma in 260 patients (47%). Gross total resection was performed in 200 patients (36%), subtotal resection in 153 (28%), partial resection in 71 patients (13%), and biopsy in 131 patients (24%). RT was most commonly applied as an adjuvant treatment. The use of chemotherapy with or without RT decreased after 2008 (from 38 to 4%). The major chemotherapeutic regimen was procarbazine, lomustine, and vincristine (PCV); however, the proportion of temozolomide increased since 2005 (up to 69%). Patient/tumor characteristics related with RT were male gender, non-seizure, multiple lobes involvement, and non-gross total resection. Chemotherapy was associated with non-gross total resection and non-astrocytoma.

CONCLUSIONS

A preference for RT and increased use of temozolomide was evident in the treatment pattern of LGG. The extent of resection was associated with a decision to perform RT and chemotherapy. To establish a robust guideline for LGG, further studies including molecular information are needed.

Metronome vs. Popular Song: A Comparison of Long-Term Retention of Chest Compression Skills after Layperson Training for Cardiopulmonary Resuscitation

Introduction

Long-term retention of cardiopulmonary resuscitation (CPR) skill is challenging for layperson trainees. This study compared the long-term retention of chest compression skills after either metronome-guided (MG) or popular song-guided (PG) CPR training.

Methods

This was a prospective randomised simulation trial. Untrained laypersons were randomly allocated to MG (n=61) or PG (n=68) groups at CPR training sessions. After CPR training, each participant performed 5-cycle CPR using a manikin with a Skill-Reporter™ immediately and six months afterwards.

Results

Immediately after training, the mean compression rate (MCR) was slightly higher in the PG than the MG group (107.4 vs. 102.2/min; p<0.0001), but there was no significant difference in the proportions of participants with an appropriate chest compression rate (100-120/min) (PSACCR) between the MG and PG (53/61 (86.9%) vs. 65/68 (95.6%); p=0.114). Six months later, MCR was faster in the MG than the PG (124.8 vs. 110.0/min; p<0.0001), and PSACCR in the PG was higher than that in the MG (62/68 (91.2%) vs. 25/61 (41.0%); p<0.0001). In both tests, there were no significant differences in other chest compression parameters of between the two groups, except for a minimal difference in incomplete chest release.

Conclusion

CPR training using a popular song is more effective than metronome-guided training in helping laypersons to maintain recommended compression rates after 6 months. (Hong Kong j.emerg.med. 2016;23:145-152)

Maximum surgical resection and adjuvant intensity-modulated radiotherapy with simultaneous integrated boost for skull base chordoma

BACKGROUND

Local recurrence is common after surgical resection of clivus chordoma. We report the results of maximum surgical resection followed by intensity-modulated radiotherapy with simultaneous integrated boost (IMRT-SIB).

METHODS

We reviewed 14 consecutive clivus chordoma cases undergoing postoperative IMRT-SIB using the institutional protocol between 2005 and 2013. Total and near-total resections were achieved in 11 patients (78.6 %), partial in 2 patients (14.3 %), and 1 patient (7.1 %) received RT for recurrent tumor after total resection. Gross residual or the high-risk area defined the planning target volume (PTV)1; PTV2 was the postoperative tumor bed plus a 3-5-mm margin, and PTV3 was PTV2 plus a 5-10 mm margin. A moderate hypofractionation schedule was used: doses to PTV1, PTV2 and PTV3 were 3.9 Gy, 3.15 Gy and 2.8 Gy through 15 fractions for the first two patients, and the rest received 2.5 Gy, 2.2 Gy and 1.8 Gy through 25 fractions. The biologically equivalent dose in 2-Gy fractions (EQD2) was 65-68 Gy for PTV1, 52-56 Gy for PTV2, and 44.3-44.8 Gy for PTV3.

RESULTS

Median follow-up was 41 months. Eight patients were free of disease for median 42.5 months (range 23-91 months), four patients had stable disease for median 60.5 months (range 39-113 months), and 1 patient showed partial response for 38 months after RT. Local progression was seen in one patient who received EQD2 67.8 Gy after partial resection. Estimated 5-year progression-free and overall survival rates were 92.9 %. Surgery improved the neurologic deficit in six patients, and IMRT-SIB was well tolerated without lasting toxicity.

CONCLUSION

Our experience suggests that maximum resection and high-dose IMRT-SIB can achieve local control without significant morbidities.