Surgical Site Infection After Autologous Cranioplasty for Decompressive Craniectomy in Traumatic Brain Injury: A Retrospective Review of Two Level 1 Trauma Centers.

OBJECT: Surgical site infection (SSI) after cranioplasty can result in unnecessary morbidity. This analysis was designed to determine the risk factors of SSI after cranioplasty in patients who received a decompressive craniectomy with the autologous bone for traumatic brain injury (TBI). METHODS: A retrospective review was performed at two level 1 academic trauma centers for adult patients who underwent autologous cranioplasty after prior decompressive craniectomy for TBI. Demographic and procedural variables were collected and analyzed for associations with an increased incidence of surgical site infection with two-sample independent t tests and Mann Whitney U tests, and with a Bonferroni correction applied in cases of multiple comparisons. Statistical significance was reported with a P value of < 0.05. RESULTS: A total of 71 patients were identified. The mean interval from craniectomy to cranioplasty was 99 days (7-283), and 3 patients developed SSIs after cranioplasty (4.2%). Postoperative drain placement (P > 0.08) and administration of intrawound vancomycin powder (P = 0.99) were not predictive of infection risk. However, a trend was observed suggesting that administration of prophylactic preoperative IV vancomycin is associated with a reduced infection rate. CONCLUSIONS: The SSI rate after autologous cranioplasty in TBI patients is lower than previously reported for heterogeneous groups and indications, and the infection risk is comparable to other elective neurosurgical procedures. As such, the authors recommend attempting to preserve native skull and perform autologous cranioplasty in this population whenever possible.

Unusual skull tumors with psammomatoid bodies: a diagnostic challenge.

AIM: We describe a series of three diagnostically challenging, histologically similar fibro-osseous skull masses. METHODS: The cases were identified in our archives among 50,000 neuropathology specimens. A comprehensive review of the histological, immunohistochemical, ultrastructural, and imaging features as well as the clinical outcome was performed. RESULTS: The routine histology was similar in all 3 cases and showed spindle cell proliferations with frequent calcospheres or psammomatoid bodies. There was no evidence of an underlying subdural component. Immunohistochemistry for the meningioma markers EMA and SSTR2A raised the possibility of intraosseous meningioma, as all 3 lesions were convincingly positive for epithelial membrane antigen (EMA) and 1 lesion was convincingly positive for the somatostatin receptor subtype 2A (SSTR2A); weak, questionable positivity for SSTR2 was present in the remaining 2 cases. In addition, electron microscopy was available in 1 case and showed features consistent with meningioma. CONCLUSIONS: Overall, the findings were most consistent with intraosseous meningioma. Primary intraosseous meningiomas are rare lesions that may present a diagnostic challenge. It is important to consider meningiomas in the differential diagnosis, as extradural meningiomas are associated with an increased risk of recurrence and may occasionally undergo malignant transformation.
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Pre-treatment factors associated with detecting additional brain metastases at stereotactic radiosurgery.

The number of brain metastases identified on diagnostic magnetic resonance imaging (MRI) is a key factor in consideration of stereotactic radiosurgery (SRS). However, additional lesions are often detected on high-resolution SRS-planning MRI. We investigated pre-treatment clinical characteristics that are associated with finding additional metastases at SRS. Patients treated with SRS for brain metastases between the years of 2009-2014 comprised the study cohort. All patients underwent frame-fixed, 1 mm thick MRI on the day of SRS. Patient, tumor, and treatment characteristics were analyzed for an association with increase in number of metastases identified on SRS-planning MRI. 289 consecutive SRS cases were analyzed. 725 metastases were identified on pre-treatment MRI and 1062 metastases were identified on SRS-planning MRI. An increase in the number of metastases occurred in 34 % of the cases. On univariate analysis, more than four metastases and the diameter of the largest lesion were significantly associated with an increase in number of metastases on SRS-planning MRI. When stratified by the diameter of the largest lesion into <2, 2-3, or ≥3 cm, additional metastases were identified in 37, 29, and 18 %, respectively. While this increase in the number of metastases is largely due to the difference in imaging technique, the number and size of the metastases were also associated with finding additional lesions. These clinical factors may be considered when determining treatment options for brain metastases.

Management of intracranial aneurysms associated with arteriovenous malformations.

Intracranial or brain arteriovenous malformations (BAVMs) are some of the most interesting and challenging lesions treated by the cerebrovascular neurosurgeon. It is generally believed that the combination of BAVMs and intracranial aneurysms (IAs) is associated with higher hemorrhage rates at presentation and higher rehemorrhage rates and thus with a more aggressive course and natural history. There is wide variation in the literature on the prevalence of BAVM-associated aneurysms (range 2.7%-58%), with 10%-20% being most often cited in the largest case series. The risk of intracranial hemorrhage in patients with unruptured BAVMs and coexisting IAs has been reported to be 7% annually, compared with 2%-4% annually for those with BAVM alone. Several different classification systems have been applied in an attempt to better understand the natural history of this combination of lesions and implications for treatment. Independent of the classification used, it is clear that a few subtypes of aneurysms have a direct hemodynamic correlation with the BAVM itself. This is exemplified by the fact that the presence of a distal flow-related or an intranidal aneurysm appears to be associated with an increased hemorrhage risk, when compared with an aneurysm located on a vessel with no direct supply to the BAVM nidus. Debate still exists regarding the etiology of the association between those two vascular lesions, the subsequent implications for patients' risk of hemorrhagic stroke, and finally the determination of which patients warrant treatment and when. The ultimate goals of the treatment of a BAVM associated with an IA are to prevent hemorrhage, avoid stepwise neurological deterioration, and eliminate the mortality risk associated with recurrent hemorrhagic events. The treatment is only justifiable if the risks associated with an intervention are lower than or equivalent to the long-term risks of disability or mortality caused by the lesion itself. When faced with this difficult decision, a few questions need to be answered by the treating neu-rosurgeon: What is the mode of presentation? What is the symptomatic lesion? Which one of the lesions bled? What is the relationship between the BAVM and IA? Is it possible to safely treat both BAVM and IA? The objective of this review is to discuss the demographics, natural history, classification, and strategies for management of BAVMs associated with IAs.

The treatment of cavernous sinus meningiomas: evolution of a modern approach.

Cavernous sinus meningiomas (CSMs) are challenging lesions for the skull base neurosurgeon to manage given their close association with cranial nerves II-VI and the internal carotid artery. In the 1980s and early 1990s, with advancements in microsurgical techniques, increasing knowledge of the relevant microsurgical neuroanatomy, and the advent of advanced skull base surgical approaches, the treatment of CSMs involved attempts at gross-total resection (GTR). Initial fervor for a surgical cure waned, however, as skull base neurosurgeons demonstrated the limits of complete resection in this region, the ongoing issue of potential tumor recurrences, and the unacceptably high cranial nerve and vascular morbidity associated with this strategy. The advent of radiosurgery and its documented success for tumor growth control and limited morbidity in cavernous lesions has helped to shift the treatment goals for CSMs from GTR to tumor control and symptom relief while minimizing treatment- and lesion-associated morbidity. The authors review the relevant microanatomy of the cavernous sinus with anatomical and radiographic correlates, as well as the various treatment options. A modernized, multimodality treatment algorithm to guide management of these lesions is proposed.

The far-lateral approach for foramen magnum meningiomas.

Foramen magnum meningiomas (FMMs) are slow growing, most often intradural and extramedullary tumors that pose significant challenges to the skull base neurosurgeon. The indolent clinical course of FMMs and their insidious onset of symptoms are important factors that contribute to delayed diagnosis and relative large size at the time of presentation. Symptoms are often produced by compression of surrounding structures (such as the medulla oblongata, upper cervical spinal cord, lower cranial nerves, and vertebral artery) within a critically confined space. Since the initial pathological description of a FMM in 1872, various surgical approaches have been described with the aim of achieving radical tumor resection. The surgical treatment of FMMs has evolved considerably over the last 4 decades due to the progress in microsurgical techniques and development of a multitude of skull base approaches. Posterior and posterolateral FMMs can be safely resected via a standard midline suboccipital approach. However, controversy still exits regarding the optimal management of anterior or anterolateral lesions. Independently of technical variations and the degree of bone removal, all modern surgical approaches to the lower clivus and anterior foramen magnum derive from the posterolateral (or far-lateral) craniotomy originally described by Roberto Heros and Bernard George. This paper is a review of the surgical management of FMMs, with emphasis on the far-lateral approach and its variations. Clinical presentation, imaging findings, important neuroanatomical correlations, recurrence rates, and outcomes are discussed.

Evaluating risk of recurrence in patients with meningioma.

OBJECTIVE: Meningioma prognostication and treatment continues to evolve with an increasing understanding of tumor biology. In this study, the authors aimed to test conventional predictors of meningioma recurrence, histopathology variables for which there exists some controversy (brain invasion), as well as a novel molecular-based location paradigm. METHODS: This is a retrospective study of a consecutive series of patients with WHO grade I-III meningioma resected at The University of Texas Southwestern Medical Center between 1994 and 2015. Time to meningioma recurrence (i.e., recurrence-free survival [RFS]) was the primary endpoint measured. Kaplan-Meier curves were constructed and compared using log-rank tests. Cox univariate and multivariate analyses were performed to identify predictors of RFS. RESULTS: A total of 703 consecutive patients with meningioma underwent resection at The University of Texas Southwestern Medical Center between the years 1994 and 2015. A total of 158 patients were excluded for insufficient follow-up (< 3 months). The median age of the cohort was 55 years (range 16-88 years) and 69.5% (n = 379) were female. The median follow-up was 48 months (range 3-289 months). There was not a significantly increased risk of recurrence in patients with evidence of brain invasion, in patients with otherwise WHO grade I meningioma (Cox univariate HR 0.92, 95% CI 0.44-1.91, p = 0.82, power 4.4%). Adjuvant radiosurgery to subtotally resected WHO grade I meningiomas did not prolong the time to recurrence (n = 52, Cox univariate HR 0.21, 95% CI 0.03-1.61, p = 0.13, power 71.6%). Location (midline skull base, lateral skull base, and paravenous) was significantly associated with RFS (p < 0.01, log-rank test). In patients with high-grade meningiomas (WHO grade II or III), location was predictive of RFS (p = 0.03, log-rank test), with paravenous meningiomas exhibiting the highest rates of recurrence. Location was not significant on multivariate analysis. CONCLUSIONS: The data suggest that brain invasion does not increase the risk of recurrence in otherwise WHO grade I meningioma. Adjuvant radiosurgery to subtotally resected WHO grade I meningiomas did not prolong the time to recurrence. Location categorized by distinct molecular signatures did not predict RFS in a multivariate model. Larger studies are needed to confirm these findings.

Endoscopic endonasal approach to the craniovertebral junction.

The surgical approach to lesions of the ventral craniovertebral junction (CVJ) has evolved significantly in the last several years with the advent of endoscopic skull base surgery. Differing pathologies of the CVJ can result in irreducible compression of the cervicomedullary region. The endoscopic endonasal approach lends itself well to this region due to the ventral location, and while there is a steep learning curve, is a safe and effective way to perform decompression of the cervicomedullary region. Herein, we discuss the anatomy of the CVJ, preoperative evaluation and surgical considerations, our surgical approach, complications, and outcomes.

Hearing Preservation After Intervention in Vestibular Schwannoma.

OBJECTIVE: This study aimed to assess the durability of audiological outcomes after radiation and surgery in the management of vestibular schwannoma. STUDY DESIGN: Retrospective review. SETTING: Tertiary academic center. PATIENTS: Adults with sporadic vestibular schwannoma and serviceable hearing at the time of intervention. INTERVENTIONS: Gamma Knife, middle cranial fossa, or retrosigmoid approaches. MAIN OUTCOME MEASURES: Pure-tone audiometry and speech discrimination scores. RESULTS: Postintervention serviceable hearing (class A/B) was preserved in 70.4% (n = 130; mean follow-up, 3.31 yr; range, 0-15.25 yr). Of the 49 patients treated with radiation, 19 (39.6%) had serviceable hearing at last follow-up, compared with 38 (46.9% of 81) who underwent retrosigmoid (n = 36 [44.4%]) and middle cranial fossa (n = 45 [55.6%]) approaches (odds ratio [OR], 1.40; 95% confidence interval [CI], 0.67-2.82; p = 0.47). A matched analysis by age, tumor volume, and preintervention hearing (n = 38) also found no difference in hearing preservation (HP) likelihood between surgery and radiation (OR, 2.33; 95% CI, 0.24-35.91; p = 0.59). After initial HP, 4 (9.5%) surgical versus 10 (37.0%) radiated patients subsequently lost residual serviceable (A/B) hearing (OR, 0.18; 95% CI, 0.06-0.69; p = 0.01) at a mean 3.74 ± 3.58 and 4.73 ± 3.83 years after surgery and radiation, respectively. Overall, 5- and 10-year HP rates (A/B) after initially successful HP surgery were 84.4 and 63.0%, respectively. However, survival estimates declined to 48.9% at 5 years and 32.7% at 10 years when patients with immediate postoperative serviceable hearing loss were also included, which were comparable to radiation-HP rates at 5 and 10 years of 28.0 and 14.2%, respectively ( p = 0.75). CONCLUSIONS: After vestibular schwannoma intervention, overall HP was similar between radiated and surgical cohorts. However, when successful, surgical approaches offered more durable hearing outcomes at long-term follow-up.

Distant Pituitary Adenoma Spread: A Systematic Review and Report of 2 Cases.

BACKGROUND: Distant spread of pituitary adenoma outside the sellar/suprasellar region is classified as pituitary carcinoma. Cerebrospinal fluid (CSF)-born spread of pituitary adenoma can occur after tumor cell spillage into the CSF space after surgery, irradiation, or apoplexy and is not necessarily related to intrinsic tumor biology. OBJECTIVE: To systematically review the literature and describe the clinical characteristics and treatment strategies of patients with pituitary carcinomas. We further present 2 cases from our institution. METHODS: A single-center retrospective review of patients with pituitary adenoma spread to distant intracranial locations between 2000 and 2020 was performed. Electronic databases were searched from their inception to May 25, 2021, and studies describing patients with pituitary spread to distant locations were included. RESULTS: Of 1210 pituitary adenoma cases reviewed, 2 (0.16%) showed tumor spread to distant locations. We found 134 additional cases (from 108 published articles) resulting in a total of 136 cases (61.9% were male). The time to tumor spread ranged between 0 and 516 months (median: 96 months). The follow-up duration ranged between 0 and 240 months (median: 11.5 months). All but 2 patients (98.5%) underwent surgical resection before adenoma spread. The 2 exceptions included a patient with evidence of an apoplectic event on autopsy and another patient with leptomeningeal pituitary spread but an unclear history of apoplexy. Elevated tumor markers were not linked to poor outcomes. CONCLUSION: Distant spread of pituitary adenoma may occur after surgery, irradiation, or apoplexy. It is not necessarily associated with a malignant clinical course.

Facial Nerve Outcomes After Vestibular Schwannoma Microsurgical Resection in Neurofibromatosis Type 2.

OBJECTIVE: The aim of this study is to investigate facial nerve outcomes after microsurgical resection in neurofibromatosis type 2 (NF2) compared to sporadic tumors. STUDY DESIGN: Single institutional retrospective chart review. SETTING: Tertiary referral center. METHODS: All adult patients with NF2 vestibular schwannoma (VS) or sporadic VS who underwent microsurgical resection from 2008 to 2019 with preoperative magnetic resonance imaging (MRI) and 1 year of postsurgical follow-up were included. The primary outcome measure was postoperative House-Brackmann (HB) facial nerve score measured at first postoperative visit and after at least 10 months. RESULTS: In total, 161 sporadic VSs and 14 NF2 VSs met inclusion criteria. Both median tumor diameter (NF2, 33.5 mm vs sporadic, 24 mm, P = .0011) and median tumor volume (NF2, 12.4 cm3 vs sporadic, 2.9 cm3, P = .0005) were significantly greater in patients with NF2. The median follow-up was 24.9 months (range, 12-130.1). Median facial nerve function after 1 year for patients with NF2 was HB 3 (range, 1-6) compared to HB 1 (range, 1-6) for sporadic VS (P = .001). With multivariate logistic regression, NF2 tumors (odds ratio [OR] = 13.9, P = .001) and tumor volume ≥3 cm3 (OR = 3.6, P = .025) were significantly associated with HB ≥3 when controlling for age, sex, extent of tumor resection, translabyrinthine approach, and prior radiation. CONCLUSION: Tumor volume >3 cm3 and NF2 tumors are associated with poorer facial nerve outcomes 1 year following microsurgical resection.

The Association of Vestibular Schwannoma Volume With Facial Nerve Outcomes After Surgical Resection.

OBJECTIVE: To explore the relationship between tumor size and facial nerve outcomes following vestibular schwannoma (VS) resection. STUDY DESIGN: Single institutional retrospective chart review of all adult patients with untreated sporadic VS who underwent surgical resection from 2008 to 2018 with preoperative magnetic resonance imaging (MRI) and 1 year of follow-up. The primary outcome measure was facial nerve outcome as assessed by the House-Brackmann facial nerve grading system. RESULTS: One hundred sixty-seven patients, 54.5% female, with a median age of 49 years (20-76 years), were identified who underwent VS resection. Surgical resection was performed by translabyrinthine (76.7%), middle cranial fossa (14.4%), retrosigmoid (7.2%), and transpromontorial (1.8%) approaches. The median tumor diameter and volume were 25.3 mm (range: 4.1-47.1 mm) and 3.17 cm3 (range: 0.01-30.6 cm3 ), respectively. The median follow-up was 24.2 months (range: 12-114.2 months). Gross total resection was performed in 79% of cases, with residual tumor identified on MRI in 17% of cases. For patients with tumors <3 cm3 , 92.7% had grade 1 or 2 facial function after at least 1 year follow-up, compared to 81.2% for those with tumors >3 cm3 (univariate logistic regression OR = 2.9, P = .03). Tumor volume >3 cm3 was predictive of facial weakness on multivariate regression analysis (OR = 7.4, P = .02) when controlling for surgical approach, internal auditory canal extension, anterior extension, age, gender, and extent of resection. CONCLUSIONS: Tumor volume >3 cm3 is associated with worse facial nerve outcomes 12 months following surgical resection. LEVEL OF EVIDENCE: IV Laryngoscope, 131:E1328-E1334, 2021.

Biplane Fluoroscopic-Guided Balloon Rhizotomy for Trigeminal Neuralgia: A Technical Note.

BACKGROUND: The classic percutaneous technique used to cannulate the foramen ovale for the treatment of trigeminal neuralgia can place important anatomic structures, such as the distal cervical internal carotid artery, at risk. OBJECTIVE: To use fixed anatomic landmarks to safely and reliably locate the foramen ovale on anteroposterior (AP) fluoroscopy. METHODS: Locating the foramen ovale was initially tested using AP fluoroscopy on cadaveric skulls in the neurosurgical simulation lab. Fluoroscopic landmarks were identified and utilized to assist in successfully locating the foramen ovale during percutaneous balloon rhizotomy procedures in patients with trigeminal neuralgia. This technique has been successfully used in multiple patients. In this report, we describe our technique in detail. RESULTS: The AP fluoroscopy is directed laterally in the coronal plane until a line drawn inferiorly from the lateral orbital rim bisects the inner concavity of the mandibular angle. Fluoroscopy is then directed inferiorly until the top of the petrous ridge bisects the mandibular ramus. The foramen ovale will come into view within the window between the mandibular ramus and hard palate. Two case illustrations are provided. CONCLUSION: Balloon rhizotomy is a commonly used treatment option for trigeminal neuralgia. Direct visualization of the foramen ovale can reliably be achieved on AP fluoroscopy using specific anatomic landmarks. This technique can be utilized to increase the accuracy and safety of the procedure.

Retrosigmoid Craniectomy for Vestibular Schwannoma with Hearing Preservation.

Objectives To describe a retrosigmoid craniectomy, hearing-preservation approach for resection of vestibular schwannoma. Design/Setting/Participants A video of a single patient undergoing the above approach at a tertiary care skull base surgery program. Results This video demonstrates a retrosigmoid craniectomy approach for resection of an enlarging intracanalicular vestibular schwannoma in a patient with normal hearing. The video highlights the pertinent surgical anatomy and outlines in a step-by-step fashion the surgical steps. The patient obtained a gross total resection with preservation of hearing. Conclusion A retrosigmoid craniectomy approach for vestibular schwannoma offers a potentially hearing preservation approach for selected tumors. The link to the video can be found at: https://youtu.be/VM663XztRZw .

Transcanal Microscopic Transpromontorial Approach for Vestibular Schwannoma.

Objectives This video demonstrates the transcanal transpromontorial approach for resection of vestibular schwannoma. Design/Setting/Participants Present study is based on a video of a single patient undergoing the above approach at a tertiary care skull base surgery program. Results This video demonstrates a transcanal microscopic transpromontorial approach for resection of an enlarging intracanalicular vestibular schwannoma in a young patient with nonserviceable hearing. The video highlights the pertinent surgical anatomy and outlines, in a step-by-step fashion, the approach to the internal auditory canal via this minimally invasive approach. The surgical indications and reconstructive techniques are also discussed ( Fig. 1 ). Conclusions A transcanal microscopic transpromontorial approach for vestibular schwannoma is feasible and offers a minimally invasive option for patients electing for microsurgical resection. The link to the video can be found at: https://youtu.be/-oKkRooytws .

Combined Microsurgical, Endovascular, and Endoscopic Approach to the Treatment of a Giant Vertebrobasilar Aneurysm.

BACKGROUND: Dolichoectasia is defined as elongation and dilatation of a blood vessel. In the intracranial circulation, the basilar artery is affected in 80% of cases. These are challenging lesions with an aggressive natural history, and treatment carries a relatively high rate of morbidity and mortality. We describe a case of multimodal treatment including endovascular, open microsurgical, and endoscopic endonasal approach (EEA) for management. OBJECTIVE: To describe the technical nuance of the addition of the EEA for management of posterior circulation dolichoectasia. METHODS: A 44-yr-old Hispanic woman with a 2-mo history of progressive headaches, gait disturbance, and lower cranial nerve dysfunction presented with acute neurologic decline. MRI demonstrated a dolichoectatic vertebrobasilar system with a giant 4.5-cm fusiform basilar aneurysm. RESULTS: She underwent concomitant endovascular bilateral vertebral artery sacrifice with suction decompression and trapping by clip ligation distal to the lesion. Postoperatively, she developed symptomatic pontine compression. She was then taken for a transclival EEA for intra-aneurysmal thrombectomy. Thereafter, she made a significant functional recovery. CONCLUSION: The addition of endoscopic reconstruction to the treatment of a dolichoectatic basilar aneurysm is an operative nuance that can be employed in treating these highly morbid lesions. This case describing a multimodal treatment paradigm including EEA reconstruction can serve as an example for the future of treatment select cases of dolichoectasia of the vertebrobasilar complex.

Fractionated CyberKnife Stereotactic Radiotherapy for Perioptic Pituitary Adenomas.

OBJECTIVE: Stereotactic radiosurgery (SRS) is the reference standard for radiotherapy for pituitary adenomas but has been limited to lesions with sufficient distance (i.e., >3 mm) from the optic apparatus. We used marginless, fractionated (i.e., 25-28 fractions) stereotactic radiotherapy and the CyberKnife to treat pituitary adenomas that were not eligible for SRS. We present the clinical outcomes, including local control, endocrine function, and toxicity from modern fractionated radiotherapy. METHODS: A total of 53 patients were treated for pituitary adenomas within 3 mm of the optic apparatus. The primary endpoint was tumor control with the secondary endpoints of vision and pituitary function preservation and endocrine control in hormone-secreting tumors. RESULTS: The tumor control rate as measured on magnetic resonance imaging as either stable or decreased in size was 98.1% (52 of 53) at a mean follow-up of 32.5 months (range, 3-77). All patients experienced preservation or improvement of their preexisting vision status. No change in pituitary function was noted in 52 of the 53 patients (98.1%). One patient experienced worsening of pituitary function secondary to pituitary apoplexy that occurred 4 months after treatment. The endocrine control rate in hormone-secreting tumors was 75% (6 of 8). CONCLUSIONS: Marginless, fractionated CyberKnife radiotherapy demonstrated excellent local tumor control and endocrine control rates, comparable to those with SRS, with preservation of vision in patients with adenomas in close proximity to the optic pathway.

Neoadjuvant Stereotactic Radiosurgery Before Surgical Resection of Cerebral Metastases.

OBJECTIVE: Stereotactic radiosurgery (SRS) has redefined the treatment paradigm for cerebral metastases. The benefits of SRS after surgical resection of a metastatic brain tumor have been well-defined. However, it is unclear whether preoperative SRS can improve the outcomes in select patients. The present study examined the safety and efficacy of preoperative neoadjuvant SRS (NaSRS) for the treatment of cerebral metastases. METHODS: We performed a retrospective review of 12 patients treated at The University of Texas Southwestern Medical Center. All patients underwent NaSRS, followed by surgical resection of a cerebral metastasis, from 2011 to 2015. Recurrence and overall survival were characterized using Kaplan-Meier and log-rank analyses. RESULTS: The mean age was 57.5 years (range, 39-69). The median follow-up period was 13 months (range, 1-22.6). The median maximum tumor diameter was 3.66 cm (range, 2.19-4.85). The 6- and 12-month local control rates were 81.8% and 49.1%, respectively. The distant disease control rates were 72.7% and 14.5% at 6 and 12 months, respectively. Overall survival was 83.3% and 74.1% at 6 and 12 months, respectively. Two patients developed leptomeningeal disease at a mean of 11.3 months. A trend toward increased local failure was seen with larger tumor volumes and diameters (P = 0.06). CONCLUSIONS: NaSRS is a promising new approach for the treatment of select cerebral metastases that require surgical intervention. The approach is safe and effective at achieving local control. Further randomized studies with larger patient cohorts are necessary to determine whether the long-term outcomes are improved.

Calcified Middle Cranial Fossa Mass.

A 21-year-old male presented for evaluation of transient loss of consciousness and was found to have a hyperdense mass in the left middle fossa. He underwent craniotomy for tumor resection. Intra- and extradural invasion was noted. Gross total resection was achieved. Pathology demonstrated a densely cellular neoplasm with predominately spindle cell morphology in a collagen-containing stroma, areas of vascular proliferation, focal mineralization, and regions of cartilage formation. High mitotic index and regions of necrosis were seen. Based on the final diagnosis of osteosarcoma, the patient was referred for chemotherapy and radiation. Intracranial osteosarcoma is a nonmeningiomatous mesenchymal tumor. Most osteosarcomas are meningeal-based and supratentorial. Presentation depends on tumor location and may include focal neurologic deficits, cranial neuropathy, seizures, or symptoms of increased intracranial pressure. Given the relative rarity of intracranial osteosarcoma, there are no established guidelines for treatment, and therapy is guided by experience with systemic osteosarcoma. Gross total resection is recommended whenever feasible. Both chemotherapy and radiation therapy are used as adjuvant therapy. Regardless of treatment, osteosarcoma remains a highly aggressive malignancy with a poor prognosis. Morbidity and mortality may be the result of local recurrence or development of pulmonary or skeletal metastasis.

Symptomatic Parietal Intradiploic Encephalocele-A Case Report and Literature Review.

Encephalocele is a rare condition that consists of herniation of cerebral matter through openings of dura and skull. A majority of encephaloceles are congenital and manifest in childhood. We present a case of a 45-year-old man presenting with contralateral hemiparesis and found to have an extremely rare phenomenon of a symptomatic posttraumatic parietal intradiploic encephalocele (IE) manifesting 36 years following pediatric traumatic head injury. Computed tomography and magnetic resonance imaging confirmed herniation of brain tissue into the intradiploic space. Surgical treatment with reduction of the encephalocele achieved near resolution of preoperative hemiparesis on follow-up. The pathogenesis and a literature review of IE are discussed.