Novel Intrafraction Motion Tracking During Postoperative Spine Stereotactic Irradiation for a Patient With Carbon Fiber Fixation Hardware

Carbon-fiber reinforced (CFR) polyetheretherketone hardware is an alternative to traditional metal hardware used for spinal fixation surgeries before postoperative radiation therapy for patients with spinal metastases. CFR hardware's radiolucency decreases metal artifact, improving visualization and accuracy of treatment planning. We present the first clinical use and proof of principle of CFR spinal hardware with tantalum markers used for successful tracking of intrafraction motion (IM) using Varian TrueBeam IMR (Intrafraction Motion Review) software module during postoperative spine stereotactic radiation. A 63-year-old woman with history of endometrial cancer presented with acute back pain. Imaging demonstrated pathologic T12 vertebral fracture with cord compression. She underwent T12 vertebrectomy with circumferential decompression and posterior instrumented T10-L2 fusion at our facility using CFR-polyetheretherketone hardware with tantalum screw markers followed by postoperative stereotactic body radiation therapy to 3000 cGy in 5 fractions delivered to T11-T12. Tantalum screw markers were used for IMR tracking. During irradiation, 260 kV images were acquired, and IMR software was able to identify and track markers. During the entire treatment, the IM motions were less than 3 mm. This is the first presented case of CFR spinal hardware with tantalum markers used for successful IMR tracking of IM during daily spine stereotactic treatment. Future work will be needed to improve workflow and create a spine-specific IMR protocol.

Patient-Reported Cognitive Outcomes and Survival after Stereotactic Radiosurgery for 15 or More Brain Metastases

PURPOSE/OBJECTIVE(S)

Overall survival (OS) in metastatic cancer patients has been improving with continued advancements, necessitating greater attention to treatment related toxicities. Patients with ≥ 15 brain metastases (BM) continue to be treated with whole brain radiation therapy (WBRT), despite poor neurocognitive outcomes. We analyzed our institutional experience of treating these patients with stereotactic radiosurgery (SRS), with the aim of evaluating safety, cognitive outcomes, and survival metrics.

MATERIALS/METHODS

Patients who received SRS for ≥ 15 BMs in 1-5 fractions from 2014-2022 using the previously described single isocenter multi-target technique were included. Cognitive outcomes were objectively evaluated using serial Patient-Reported Outcome Measurement Information System (PROMIS) scores. Kaplan-Meier method was used for survival analysis and log-rank test was used for intergroup comparisons.

RESULTS

A total of 118 patients underwent 124 courses of LINAC-based SRS. The mean and median number of lesions treated per patient was 24.8 and 20, respectively (range 15 - 94). Most common primary histologies were lung (47.6%), melanoma (21.0%), and breast (14.5%). The median SRS dose was 24 Gy (range 18 - 30 Gy) with 87.9% receiving 3 fraction SRS. At the time of SRS, 19.4% patients had received prior WBRT and 24.2% had received at least one prior SRS course. The rate of any grade radiation necrosis (RN) and ≥ grade 3 RN were 15.3% and 3.2% respectively. New onset seizures were seen in 2.4%, alopecia in 2.4%, and subjective cognitive decline in 4% of patients. Median follow-up by reverse Kaplan-Meier method was 17.8 months (m). Cognitive data was available for 38 patients. Mean PROMIS scores at baseline, 3m, 6m and 9m after SRS were 32.0, 31.6, 30.4 and 28.7 out of 40, respectively. When longitudinal trends were available, 25 of 31 patients had a stable or improved PROMIS score. The 12m local control was 97.6%. Cumulative incidence of distant intracranial failure was 79.2%. One year freedom from neurological death, leptomeningeal disease, and salvage WBRT were 85.6%, 87.6% and 71.7% respectively. Median OS from brain metastases diagnosis was 11.3m (95% CI 7.2m - 15.3m) overall, while it was 9.2m (6.5 - 11.8m) after excluding patients who had prior WBRT or SRS (n = 79). One-year survival was 40% from diagnosis and 38.7% from SRS. On Cox regression analysis, prior WBRT (p = 0.002), higher KPS (p = 0.050), systemic therapy after SRS (p<0.001), and controlled extracranial disease (p = 0.007) predicted for improved OS.

CONCLUSION

We present here the largest study evaluating SRS for patients with ≥ 15 BMs. We found that SRS was safe, had favorable cognitive outcomes, and comparable survival outcomes to contemporary studies evaluating WBRT in this patient population. Treatment-naïve patients had a median survival of > 6 months, long enough to benefit from cognitive sparing with SRS. Our study supports further randomized studies comparing SRS and memory avoidance WBRT approaches for patients with ≥ 15 BMs.

Vertebral Compression Fracture Post Spine Stereotactic Body Radiotherapy: The Role of Vertebral Endplate

PURPOSE/OBJECTIVE(S)

Maintaining hydrostatic pressure -via Pascal's Principle- between vertebral bodies is essential to decrease the chance of vertebral compression fracture (VCF). Vertebral endplates (EP) play an essential role in this matter through maintaining the mechanical environment as well as the proper nutrition of avascular discs. The purpose of this study is to establish the correlation of VCF with disrupted EP by tumor involvement.

MATERIALS/METHODS

A retrospective analysis of de novo spine metastases treated with stereotactic body radiotherapy (SBRT) between 2013-2019. Patients (pts) with previous surgical intervention were excluded. VCF defined as new or progression of existing loss of vertebral body height. The vertebral EP region defined in relation to the vertebral body as superior EP vs inferior EP. Kaplan-Meier curves used to analyze the variables. A multivariate proportional hazard model used to assess the risk of all covariates.

RESULTS

A total of 111 pts were treated with SBRT with a median dose of 27 Gy (10-35 Gy). Median follow-up was 18 months (1.2-107). The median age was 60 years (24-87) and 59 were males (53%) and 52 were females (47%). The median body mass index (BMI) was 27 kg/m2 (16-47). Almost 9 pts diagnosed with osteoporosis prior radiation. Twelve pts received prolonged steroids. Twenty pts received bisphosphonate and 8 pts received denosumab. The median PTV was 50cc (8-465) and median Conformity Index was 1.05 (0.42-1.4). Almost 75% of pts received >95% of the dose covering 100% of the PTV. The most common histopathologies were renal cell carcinoma (25%), lung (13%) and breast (11%). Most of the pts (77%) had SINS score of 7 or less. 48 pts (43%) had either superior or inferior EP disruption secondary to the tumor at the time of radiation. Twenty pts (18%) had both superiorly and inferiorly disrupted EP. Around 20 pts (18%) developed VCF. The median time to VCF was 5.2 months (1.1-57.4). The one-year cumulative incidence of VCF was 18%. The 1-year cumulative incidence of VCF with either superiorly and/or inferiorly disrupted EP was 29% vs 6%, p value <0.001. The 1-year cumulative incidence of VCF with both superiorly and inferiorly disrupted EP was 57% vs 7% (p value <0.001). The median time to VCF was earlier in pts with both disrupted EP (2.4 months vs 5.7 months, p value <0.05). Other risk factors like SINS score of >7 and local recurrence (LR) associated with higher risk of VCF. On multivariate analysis, LR (HR 8.2 [CI 2.4-28, p- value <0.001]), tumor disrupting the EP (HR 4.5 [CI 1.3-16, p-value<0.018]) and SINS score of seven and above (HR 1.7 [CI 1.3-2.25, p-value <0.001]) correlated with the VCF risk.

CONCLUSION

In this retrospective analysis, tumor disrupting the EP, disease recurrence and high SINS score increased the risk of VCF. Cement augmentation either prophylactically or immediately following SBRT is currently being studied in a prospective trial within our institution.

Feasibility, safety, and efficacy of circumferential spine stereotactic body radiotherapy

Background

With advances in systemic therapy translating to improved survival in metastatic malignancies, spine metastases have become an increasingly common source of morbidity. Achieving durable local control (LC) for patients with circumferential epidural disease can be particularly challenging. Circumferential stereotactic body radiotherapy (SBRT) may offer improved LC for circumferential vertebral and/or epidural metastatic spinal disease, but prospective (and retrospective) data are extremely limited. We sought to evaluate the feasibility, toxicity, and cancer control outcomes with this novel approach to circumferential spinal disease.

Methods

We retrospectively identified all circumferential SBRT courses delivered between 2013 and 2019 at a tertiary care institution for post-operative or intact spine metastases. Radiotherapy was delivered to 14-27.5 Gy in one to five fractions. Feasibility was assessed by determining the proportion of plans for which ≥95% planning target volume (PTV) was coverable by ≥95% prescription dose. The primary endpoint was 1-year LC. Factors associated with increased likelihood of local failure (LF) were explored. Acute and chronic toxicity were assessed. Detailed dosimetric data were collected.

Results

Fifty-eight patients receiving 64 circumferential SBRT courses were identified (median age 61, KPS ≥70, 57% men). With a median follow-up of 15 months, the 12-month local control was 85% (eight events). Five and three recurrences were in the epidural space and bone, respectively. On multivariate analysis, increased PTV and uncontrolled systemic disease were significantly associated with an increased likelihood of LF; ≥95% PTV was covered by ≥95% prescription dose in 94% of the cases. The rate of new or progressive vertebral compression fracture was 8%. There were no myelitis events or any grade 3+ acute or late toxicities.

Conclusions

For patients with circumferential disease, circumferential spine SBRT is feasible and may offer excellent LC without significant toxicity. A prospective evaluation of this approach is warranted.

Comparing Pre-Operative Versus Post-Operative Single and Multi-Fraction Stereotactic Radiotherapy for Patients with Resectable Brain Metastases

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Pre-operative radiation therapy for brain metastases may reduce meningeal disease.

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Pre-operative radiation therapy for brain metastases may reduce radionecrosis.

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Fractionated radiation therapy for brain metastases may reduce local failure.

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Fractionated pre-operative radiation therapy requires prospective validation.

Background

The standard treatment for patients with large brain metastases and limited intracranial disease is surgical resection and post-operative stereotactic radiosurgery (SRS). However, post-operative SRS still has elevated rates of local failure (LF) and is complicated by radiation necrosis (RN), and meningeal disease (MD). Pre-operative SRS may reduce the risk of RN and MD, while fractionated therapy may improve local control through delivering a higher biological effective dose. We hypothesize that pre-operative fractionated stereotactic radiation therapy (FSRT) will have less toxicity compared to patients who receive post-operative SRS or FSRT.

Methods

A multi-institutional analysis was conducted and included patients who had surgical resection and stereotactic radiation therapy to treat at least one brain metastasis. Pertinent demographic, clinical, radiation, surgical, and follow up data were collected for each patient. The primary outcome was a composite endpoint defined as patients with one of the following adverse events: 1) LF, 2) MD, and/or 3) Grade 2 or higher (symptomatic) RN.

Results

279 patients were eligible for analysis. The median follow-up time was 9 months. 87 % of patients received fractionated treatment. 29 % of patients received pre-operative treatment. The composite endpoint incidences for post-operative SRS (n = 10), post-operative FSRT (n = 189), pre-operative SRS (n = 27), and pre-operative FSRT (n = 53) were 0 %, 17 %, 15 %, and 7.5 %, respectively.

Conclusions

In our study, the composite endpoint of 7.5% for pre-operative FSRT compares favorably to our post-operative FSRT rate of 17%. Pre-operative FSRT was observed to have low rates of LF, MD, and RN. Prospective validation is needed.

Spine Stereotactic Body Radiotherapy to Three or More Contiguous Vertebral Levels

Background

With survival improving in many metastatic malignancies, spine metastases have increasingly become a source of significant morbidity; achieving durable local control (LC) is critical. Stereotactic body radiotherapy (SBRT) may offer improved LC and/or symptom palliation. However, due to setup concerns, SBRT is infrequently offered to patients with ≥3 contiguous involved levels. Because data are limited, we sought to evaluate the feasibility, toxicity, and cancer control outcomes of spine SBRT delivered to ≥3 contiguous levels.

Methods

We retrospectively identified all SBRT courses delivered between 2013 and 2019 at a tertiary care institution for postoperative or intact spine metastases. Radiotherapy was delivered to 14-35 Gy in 1-5 fractions. Patients were stratified by whether they received SBRT to 1-2 or ≥3 contiguous levels. The primary endpoint was 1-year LC and was compared between groups. Factors associated with increased likelihood of local failure (LF) were explored. Acute and chronic toxicity was assessed. In-depth dosimetric data were collected.

Results

Overall, 165 patients with 194 SBRT courses were identified [54% were men, median age was 61 years, 93% had Karnofsky Performance Status (KPS) ≥70, and median follow-up was 15 months]. One hundred thirteen patients (68%) received treatment to 1-2 and 52 to 3-7 (32%) levels. The 1-year LC was 88% (89% for 1-2 levels vs. 84% for ≥3 levels, p = 0.747). On multivariate analysis, uncontrolled systemic disease was associated with inferior LC for patients with ≥3 treated levels. No other demographic, disease, treatment, or dosimetric variables achieved significance. Rates of new/progressive fracture were equivalent (8% vs. 9.5%, p = 0.839). There were no radiation-induced myelopathy or grade 3+ acute or late toxicities in either group. Coverage of ≥95% of the planning target volume with ≥95% prescription dose was similar between groups (96% 1-2 levels vs. 89% ≥3 levels, p = 0.078).

Conclusions

For patients with ≥3 contiguous involved levels, spine SBRT is feasible and may offer excellent LC without significant toxicity. Prospective evaluation is warranted.

Dose-escalated accelerated hypofractionation for elderly or frail patients with a newly diagnosed glioblastoma

BACKGROUND

The standard of care for elderly glioblastoma patients is 40 Gy in 15 fraction radiotherapy with temozolomide (TMZ). However, this regimen has a lower biologic equivalent dose (BED) compared to the Stupp regimen of 60 Gy in 30 fractions. We hypothesize that accelerated hypofractionated radiation of 52.5 Gy in 15 fractions (BED equivalent to Stupp) will have superior survival compared to 40 Gy in 15 fractions.

METHODS

Elderly patients (≥ 65 years old) who received hypofractionated radiation with TMZ from 2010 to 2020 were included in this analysis. Overall survival (OS) and progression free survival were defined as the time elapsed between surgery/biopsy and death from any cause or progression. Baseline characteristics were compared between patients who received 40 and 52.5 Gy. Univariable and multivariable analyses were performed.

RESULTS

Sixty-six newly diagnosed patients were eligible for analysis. Thirty-nine patients were treated with 40 Gy in 15 fractions while twenty-seven were treated with 52.5 Gy in 15 fractions. Patients had no significant differences in age, sex, methylation status, or performance status. OS was superior in the 52.5 Gy group (14.1 months) when compared to the 40 Gy group (7.9 months, p = 0.011). Isoeffective dosing to 52.5 Gy was shown to be an independent prognostic factor for improved OS on multivariable analysis.

CONCLUSIONS

Isoeffective dosing to 52.5 Gy in 15 fractions was associated with superior OS compared to standard of care 40 Gy in 15 fractions. These hypothesis generating data support accelerated hypofractionation in future prospective trials.

Malignant ossifying fibromyxoid tumor of the brain treated with post-operative fractionated stereotactic radiation therapy: A case report and literature review

Background:

Ossifying fibromyxoid tumor (OFMT) is a rare musculoskeletal soft-tissue neoplasm of uncertain histogenesis most frequently occurring in the lower extremities. Conventionally, considered benign, these tumors are often managed by surgical resection followed by surveillance. However, malignant OFMTs with an increased propensity for local recurrence and distant metastasis have been recently identified, and the role of adjuvant therapy in these more aggressive cases is unclear.

Case Description:

We present, to the best of our knowledge, the first reported case of a primary, malignant, and intracranial OFMT. A 29-year-old female presented with recurrent headaches secondary to a large mass in her right frontal lobe. She underwent gross total resection of the brain mass with final pathology consistent with malignant OFMT demonstrating high-risk features including increased cellularity, grade, and mitotic activity. Due to these high-risk features, she received postoperative fractionated stereotactic radiation therapy (FSRT) to the resection cavity, and to the best of our knowledge, she represents the only known patient with OFMT to be treated with adjuvant FSRT. She tolerated the adjuvant treatment well with no acute or late toxicities and remains disease-free over 5 ½ years after resection.

Conclusion:

Adjuvant FSRT appears to be a safe and efficacious approach for managing this rare intracranial disease presentation. We review this patient’s clinical course in the context of the literature to demonstrate the difficulties associated with accurate diagnosis of this rare tumor and the controversial role of adjuvant therapy in preventing disease recurrence in this patient population.

Postoperative Stereotactic Body Radiotherapy for Spinal Metastasis and Predictors of Local Control

BACKGROUND

Spine surgery is indicated for select patients with mechanical instability, pain, and/or malignant epidural spinal cord compression, with or without neurological compromise. Stereotactic body radiotherapy (SBRT) is an option for durable local control (LC) for metastatic spine disease.

OBJECTIVE

To determine factors associated with LC and progression-free survival (PFS) for patients receiving postoperative stereotactic spine radiosurgery.

METHODS

We analyzed consecutive patients from 2013 to 2019 treated with surgical intervention followed by SBRT. Surgical interventions included laminectomy and vertebrectomy. SBRT included patients treated with 1 to 5 fractions of radiosurgery. We analyzed LC, PFS, overall survival (OS), and toxicity. Univariate and multivariate analyses were performed.

RESULTS

A total of 63 patients were treated with a median follow-up of 12.5 mo. Approximately 75% of patients underwent vertebrectomy and 25% underwent laminectomy. One-year cumulative incidence of local failure was 19%. LC was significantly improved for patients receiving radiosurgery ≤40 d from surgery compared to that for patients receiving radiosurgery ≥40 d from surgery, 94% vs 75%, respectively, at 1 yr (P = .03). Patients who received preoperative embolization had improved LC with 1-yr LC of 88% vs 76% for those who did not receive preoperative embolization (P = .037). Significant predictors for LC on multivariate analysis were time from surgery to radiosurgery, higher radiotherapy dose, and preoperative embolization. The 1-yr PFS and OS was 56% and 60%, respectively.

CONCLUSION

Postoperative radiosurgery has excellent and durable LC for spine metastasis. An important consideration when planning postoperative radiosurgery is minimizing delay from surgery to radiosurgery. Preoperative embolization and higher radiotherapy dose were associated with improved LC warranting further study.

Linear accelerator-based radiosurgery is associated with lower incidence of radionecrosis compared with gamma knife for treatment of multiple brain metastases

BACKGROUND

Gamma knife (GK) and linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) both offer excellent local control in the management of multiple brain metastases. The efficacy and toxicity of LINAC and GK SRS have not been directly compared in the modern era. We studied outcomes in patients treated with LINAC SRS and GK at two separate institutions.

METHODS

We identified patients treated with either LINAC or GK who were treated to ≥2 lesions and had available follow up. LINAC patients were treated using single-isocenter multitarget technique. We used Cox regression, Fine and Gray competing risks regression, and nearest neighbor propensity score matching to account for confounders and imbalance between cohorts. Kaplan-Meier curves were used to estimate overall survival and rates of radionecrosis.

RESULTS

We identified 391 patients who were treated in 537 courses to a total 2699 lesions (LINAC: 1014, GK: 1685). After propensity score matching, GK was associated with similar overall survival (HR = 0.86; 95% CI 0.59-1.24; p = 0.41) and higher rate of radionecrosis (HR = 3.83; 95% CI 1.66-8.84; p = 0.002) compared to LINAC. In a secondary propensity score matched analysis comparing radionecrosis in single-fraction LINAC and GK, GK remained associated with higher incidence of radionecrosis (HR = 4.42; 95% CI 1.28-15.29; p = 0.019).

CONCLUSIONS

In this multi-institutional study, we found similar overall survival with lower incidence of radionecrosis in patients treated with LINAC compared to GK SRS. These findings are hypothesis generating and should be validated in an independent cohort.

Durable complete responses in some recurrent high-grade glioma patients treated with Toca 511 + Toca FC

Background

Vocimagene amiretrorepvec (Toca 511) is an investigational gamma-retroviral replicating vector encoding cytosine deaminase that, when used in combination with extended-release 5-fluorocytosine (Toca FC), results preclinically in local production of 5-fluorouracil, depletion of immune-suppressive myeloid cells, and subsequent induction of antitumor immunity. Recurrent high-grade glioma (rHGG) patients have a high unmet need for effective therapies that produce durable responses lasting more than 6 months. In this setting, relapse is nearly universal and most responses are transient.

Methods

In this Toca 511 ascending-dose phase I trial (NCT01470794), HGG patients who recurred after standard of care underwent surgical resection and received Toca 511 injected into the resection cavity wall, followed by orally administered cycles of Toca FC.

Results

Among 56 patients, durable complete responses were observed. A subgroup was identified based on Toca 511 dose and entry requirements for the follow-up phase III study. In this subgroup, which included both isocitrate dehydrogenase 1 (IDH1) mutant and wild-type tumors, the durable response rate is 21.7%. Median duration of follow-up for responders is 35.7+ months. As of August 25, 2017, all responders remain in response and are alive 33.9+ to 52.2+ months after Toca 511 administration, suggesting a positive association of durable response with overall survival.

Conclusions

Multiyear durable responses have been observed in rHGG patients treated with Toca 511 + Toca FC in a phase I trial, and the treatment will be further evaluated in a randomized phase III trial. Among IDH1 mutant patients treated at first recurrence, there may be an enrichment of complete responders.

Single-Isocenter Multitarget Stereotactic Radiosurgery Is Safe and Effective in the Treatment of Multiple Brain Metastases

Purpose

Multiple studies have reported favorable outcomes for stereotactic radiosurgery (SRS) in the treatment of limited brain metastases. An obstacle of SRS in the management of numerous metastases is the longer treatment time using traditional radiosurgery. Single-isocenter multitarget (SIMT) SRS is a novel technique that permits rapid therapy delivery to multiple metastases. There is a lack of clinical evidence regarding its efficacy and safety. We report the outcomes of patients treated with this technique.

Methods and Materials

We reviewed the records of patients with intact or resected brain metastases treated with SRS in 1 to 5 fractions using SIMT technique at our institution, with at least 1 available follow-up brain magnetic resonance imaging. Survival, disease control, and toxicity were evaluated using Cox regression, logistic regression, and Kaplan-Meier analysis.

Results

We identified 173 patients with 1014 brain metastases. Median follow up was 12.7 months. Median beam-on time was 4.1 minutes. The median dose to the brain was 219.4 cGy. Median overall survival and freedom from intracranial progression were 13.2 and 6.3 months, respectively. Overall survival did not differ between patients treated with greater than or less than 4 lesions (hazard ratio, 1.03; 95% confidence interval 0.66-1.61; P = .91). Actuarial 1- and 2-year local control were 99.0% and 95.1%, respectively. Rates of grade 2 and grade 3 or higher radionecrosis were 1.4% and 0.9%, respectively.

Conclusions

SIMT radiosurgery delivered in 1 to 5 fractions offers excellent local control and acceptable toxicity in the treatment of multiple intact and postoperative brain metastases. This technique should be evaluated prospectively.

Stabilization of Tumor-Associated Craniovertebral Junction Instability: Indications, Operative Variables, and Outcomes

BACKGROUND

Whether primary or metastatic, tumors of the craniovertebral junction (CVJ) are rare and challenging.

OBJECTIVE

To examine the surgical indications, operative variables, and outcomes in patients with tumors of the CVJ undergoing occipitocervical (OC) stabilization.

METHODS

A single-institution, retrospective case series was performed from a prospectively maintained spine database. Patients with primary or metastatic tumors of the CVJ who underwent OC stabilization were identified. Out of 46 patients who underwent OC fusion, 39 were for tumor. Paired t -tests and Wilcoxon rank-sum tests were performed to assess for postoperative changes.

RESULTS

Ten patients (26%) harbored primary tumors, and the remaining 29 (74%) had metastatic disease. Of the metastatic patients, 14 had a neurological deficit, 10 had severe neck pain, and 5 were deemed mechanically unstable. Postoperative visual analog pain scores were significantly reduced at all 3 follow-up times ( P < .001, 95% confidence interval [CI; 3.2, 6.0]; P = .001, 95% CI [2.6, 7.7]; P = .020, 95% CI [0.6, 5.5]). The percentage of patients who were ambulatory and neurologically improved or intact remained stable postoperatively with no significant declines. There were 2 perioperative mortalities (5%), and 13 patients (33%) experienced a major complication.

CONCLUSIONS

In patients with primary or metastatic tumor of the CVJ, OC stabilization using a cervical screw-rod system affixed to a midline-keel buttress plate, with or without posterior decompression, is a reliable method for CVJ stabilization in the oncologic setting. Improvement in pain and preservation of neurological function was seen.

Quantitative validation of anti-PTBP1 antibody for diagnostic neuropathology use: Image analysis approach

Traditional diagnostic neuropathology relies on subjective interpretation of visual data obtained from a brightfield microscopy. This approach causes high variability, unsatisfactory reproducibility, and inability for multiplexing even among experts. These problems may affect patient outcomes and confound clinical decision-making. Also, standard histological processing of pathological specimens leads to auto-fluorescence and other artifacts, a reason why fluorescent microscopy is not routinely implemented in diagnostic pathology. To overcome these problems, objective and quantitative methods are required to help neuropathologists in their clinical decision-making. Therefore, we propose a computerized image analysis method to validate anti-PTBP1 antibody for its potential use in diagnostic neuropathology. Images were obtained from standard neuropathological specimens stained with anti-PTBP1 antibody. First, the noise characteristics of the images were modeled and images are de-noised according to the noise model. Next, images are filtered with sigma-adaptive Gaussian filtering for normalization, and cell nuclei are detected and segmented with a k-means-based deterministic approach. Experiments on 29 data sets from 3 cases of brain tumor and reactive gliosis show statistically significant differences between the number of positively stained nuclei in images stained with and without anti-PTBP1 antibody. The experimental analysis of specimens from 3 different brain tumor groups and 1 reactive gliosis group indicates the feasibility of using anti-PTBP1 antibody in diagnostic neuropathology, and computerized image analysis provides a systematic and quantitative approach to explore feasibility.

Local disease control after decompressive surgery and adjuvant high-dose single-fraction radiosurgery for spine metastases

Object

Adjuvant radiation following epidural spinal cord decompression for tumor is a powerful tool used to achieve local disease control and preserve neurological function. To the authors' knowledge, only 1 published report addresses adjuvant stereotactic radiosurgery after this procedure, but that study used significantly lower doses than are currently prescribed. The authors review their experience using high-dose single-fraction radiosurgery as a postoperative adjuvant following surgical decompression and instrumentation to assess long-term local tumor control, morbidity, and survival.

Methods

A retrospective chart review identified 21 patients treated with surgical decompression and instrumentation for high-grade, epidural, spinal cord compression from tumor, followed by single-fraction high-dose spinal radiosurgery (dose range 18–24 Gy, median 24 Gy). Spinal cord dose was limited to a cord maximal dose of 14 Gy. Tumor histologies, time between surgery and radiosurgery, time to local recurrence after radiosurgery as assessed by serial MR imaging, and time to death were determined. Competing risk analysis was used to evaluate these end points.

Results

In this series, 20 tumors treated (95%) were considered highly radioresistant to conventional external beam radiation. The planning target volume received a high dose (24 Gy) in 16 patients (76.2%), and a low dose (18 or 21 Gy) in 5 patients (23.8%). During the study, 15 (72%) of 21 patients died, and in all cases death was due to systemic progression as opposed to local failure. The median overall survival after radiosurgery was 310 days (range 37 days to not reached). One patient (4.8%) underwent repeat surgery for local failure and 2 patients (9.5%) underwent spine surgery for other reasons. Local control was maintained after radiosurgery in 17 (81%) of 21 patients until death or most recent follow-up, with an estimated 1-year local failure risk of 9.5%. Of the failures, 3 of 4 were noted in patients receiving low-dose radiosurgery, equaling an overall failure rate of 60% (3 of 5 patients) and a 1-year local failure estimated risk of 20%. Those patients receiving adjuvant stereotactic radiosurgery with a high dose had a 93.8% overall local control rate (15 of 16 patients), with a 1-year estimated failure risk of 6.3%. Competing risk analysis showed this to be a significant difference between radiosurgical doses. One patient experienced a significant radiation-related complication; there were no wound-related issues after radiosurgery.

Conclusions

Spine radiosurgery after surgical decompression and instrumentation for tumor is a safe and effective technique that can achieve local tumor control until death in the vast majority of patients. In this series, those patients who received a higher radiosurgical dose had a significantly better local control rate.

Postoperative continuous paravertebral anesthetic infusion for pain control in posterior cervical spine surgery: a case-control study

INTRODUCTION

Patients who undergo posterior cervical spinal fusion procedures frequently experience significant postoperative pain. Use of a local anesthetic continuous infusion pump after surgery may improve these outcome variables.

METHODS

After posterior cervical spine fusion procedures, 25 consecutive patients received continuous infusion of 0.5% bupivacaine into the subfascial aspects of the wound via an elastomeric pump. Data were collected prospectively by third party assessment using standard nursing protocols. This included numeric pain scores and opiate use over the first 4 postoperative days (PODs), length of hospitalization, and complications. In a retrospective analysis, we compared each study patient to a control patient who did not receive the continuous infusion of bupivacaine. Demographic variables and surgical procedure were similar among matched cases.

RESULTS

Patients receiving continuous local anesthetic infusion used significantly less narcotics (P < .05) during the first 4 PODs: 24.4% on day 1, 34.1% on day 2, 53.5% on day 3, and 58.1% on day 4. A lower average pain score was observed among study patients on each POD (P < .05): 31.5% less on day 1, 13.0% on day 2, 24.0% on day 3, and 35.7% on day 4. Patients with the infusion device were discharged home earlier (POD 4.9 versus 6.7; P = .024) and demonstrated improvement in time to ambulation, first bowel movement, and discontinuation of the patient-controlled analgesia machine. No complications were associated with the device.

CONCLUSION

Patients with the local anesthetic continuous infusion device required less narcotics and reported lower pain scores than control patients on each of the first 4 PODs. These results suggest that continuous infusion of local anesthetic into the paravertebral tissue during the immediate postoperative period is a safe and effective technique that achieves lower pain scores and narcotic use and improves multiple postoperative outcome variables.

The biological restoration of central nervous system architecture and function: part 1-foundations and historical landmarks in contemporary stem cell biology

Since their discovery, stem cells have fascinated scientists with their ultimate potential: the ability to cure disease, repair altered physiology, and reverse neurological deficit. Stem cell science unquestionably promises to eliminate many of the tragic limitations contemporary medicine must acknowledge, and cloning may provide young cells for an aging population. Although it is widely believed that stem cells will transform the way medicine is practiced, therapeutic interventions using stem cell technology are still in their infancy. The 3 most common stem cell sources studied today are umbilical cord blood, bone marrow, and human embryos. Although cord blood is currently used to treat dozens of disorders and bone marrow stem cells have been used clinically since the 1960s, human embryonic stem cells have yet to be successfully applied to any disease. Undeniably, stem cell therapy has the potential to be one of the most powerful therapeutic options available. In this introductory article of a 5-part series on stem cells, we narrate the evolution of modern stem cell science, delineating major landmarks that will prove responsible for taking stem cell technology from the laboratory into revolutionary clinical applications: from the first milestone of identifying the mouse hematopoietic stem cell to the latest feats of producing pluripotent stem cells without embryos at all. In Part 2, we present the evidence demonstrating the certainty of adult mammalian neurogenesis; in Parts 3 and 4, we describe neurosurgical applications of stem cell technology; and in Part 5, we discuss the philosophical and ethical issues surrounding stem cell therapy, as well as future areas of exploration.

ABERRANT ANGIOGENIC CHARACTERISTICS OF HUMAN BRAIN ARTERIOVENOUS MALFORMATION ENDOTHELIAL CELLS

OBJECTIVE

To identify and characterize the phenotypic and functional differences of endothelial cells derived from cerebral arteriovenous malformations (AVM), as compared with endothelial cells derived from a normal brain.

METHODS

Isolated AVM brain endothelial cells and control brain endothelial cells were evaluated immunohistochemically for expression of the endothelial cell markers von Willebrand factor and CD31, as well as angiogenic factors including vascular endothelial growth factor A, interleukin-8, and endothelin-1. Vascular endothelial growth factor receptors 1 and 2 were also evaluated using immunohistochemistry techniques. Functional assays evaluated cell proliferation, cytokine production, tubule formation, and cell migration using the modified Boyden chamber technique.

RESULTS

Endothelial cells derived from AVMs expressed high levels of vascular endothelial growth factor A and significantly overexpressed the vascular endothelial growth factor receptors 1 and 2 (P &lt; 0.05), as compared with control endothelial cells. In addition, comparison to control brain endothelial cells demonstrated that AVM brain endothelial cells proliferated faster, migrated more quickly, and produced aberrant tubule-like structures.

CONCLUSION

Endothelial cells derived from cerebral AVMs are highly activated cells overexpressing proangiogenic growth factors and exhibiting abnormal functions consistent with highly activated endothelial cells.

The alchemy of ideas

This article presents an assessment of the power of ideas and their role in initiating change and progress. The enormous potential cascade effect is illustrated by examining the movement of Modernism in the arts. Next, the immense scope and capabilities of the modern scientific endeavor-with robotic space exploration at the scale of 10 meters at one extreme and the wonders of nanoscience at the scale of 10 m at the other-are examined. The attitudes and philosophies of neurological surgery are related to those involved in the Modernist movement and placed on the defined scale of contemporary scientific activity.

PRINCIPLES OF GROWTH MODULATION IN THE TREATMENT OF SCOLIOTIC DEFORMITIES

INTRAOPERATIVE MANIPULATION TO correct scoliotic deformities relies upon spinal instrumentation for stabilization and fusion. However, novel strategies and innovative implant biotechnologies have emerged, applying natural growth and elongation of the immature spine for the treatment of scoliosis in young patients. In this work, we review the principles of growth modulation and the Hueter-Volkmann law as it applies to experimental models of scoliosis formation and correction. Current implant technologies, including shape memory alloy vertebral staples, growing rods, and vertical expandable titanium prosthetic ribs, are explored, with regards to implant design, surgical techniques, and clinical investigations. An exciting area of spinal implant technology is now becoming available to expand the surgical armamentarium for treating severe scoliotic deformity in young patients.

Novel Use of an Endovascular Embolectomy Device for Retrograde Suction Decompression-Assisted Clip Ligation of a Large Paraclinoid Aneurysm: Technical Case Report

Objective:

Several different methodologies for proximal occlusion and retrograde suction decompression of large paraclinoid aneurysms have been reported previously. In this article, we describe the novel use of an endovascular embolectomy device (F.A.S.T. funnel catheter; Genesis Medical Interventional, Inc., Redwood City, CA) for temporary internal carotid artery occlusion and suction decompression of an intracranial aneurysm to facilitate surgical clip ligation. The combination of atraumatic occlusion technology and large lumen size makes this technique safer and easier.

Clinical Presentation:

A 53-year-old woman with progressive headaches underwent computed tomographic angiography, which revealed an unruptured large left paraclinoid aneurysm. Cerebral angiography confirmed the diagnosis. The patient did not tolerate a balloon test occlusion for therapeutic Hunterian internal carotid occlusion. The patient was subsequently taken to the operating room for a craniotomy and clip ligation of the aneurysm.

Intervention:

A standard left pterional craniotomy was performed with opening of the sylvian fissure and exposure of the left paraclinoid aneurysm. Intraoperative angiography with introduction of a new endovascular embolectomy device was performed. The device was deployed to achieve temporary occlusion of the cervical internal carotid artery, and aspiration through the central lumen allowed for retrograde suction decompression of the aneurysm. Collapse of the aneurysm through this technique permitted visualization of the aneurysmal neck with successful clip ligation.

Conclusion:

A new endovascular embolectomy device can be used to safely perform suction decompression of large paraclinoid aneurysms to facilitate clip ligation.

Neurosurgery in the realm of 10(-9), part 1: stardust and nanotechnology in neuroscience

Nanotechnology as a science has evolved from notions and speculation to emerge as a prominent combination of science and engineering that stands to impact innumerable aspects of technology. Medicine in general and neurosurgery in particular will benefit greatly in terms of improved diagnostic and therapeutic capabilities. The recent explosion in nanotechnology products, including diverse applications such as beauty products and medical contrast agents, has been accompanied by an ever increasing volume of literature. Recent articles from our institution provided an historical and scientific background of nanotechnology, with a purposeful focus on nanomedicine. Future applications of nanotechnology to neuroscience and neurosurgery were briefly addressed. The present article is the first of two that will further this discussion by providing specific details of current nanotechnology applications and research related to neuroscience and clinical neurosurgery. This article also provides relevant perspective in scale, history, economics, and toxicology. Topics of specific importance to developments or advances of technologies used by neuroscientists and neurosurgeons are presented. In addition, advances in the field of microelectromechanical systems technology are discussed. Although larger than nanoscale, microelectromechanical systems technologies will play an important role in the future of medicine and neurosurgery. The second article will discuss current nanotechnologies that are being, or will be in the near future, incorporated into the armamentarium of the neurosurgeon. The goal of these articles is to keep the neuroscience community abreast of current developments in nanotechnology, nanomedicine, and, in particular, nanoneurosurgery, and to present possibilities for future applications of nanotechnology. As applications of nanotechnology permeate all forms of scientific and medical research, clinical applications will continue to emerge. Physicians of the present and future must take an active role in shaping the design and research of nanotechnologies to ensure maximal clinical relevance and patient benefit.

Primary intraosseous meningioma

✓Primary intraosseous meningiomas are a subtype of primary extradural meningiomas and constitute fewer than 2% of meningiomas overall, but they represent approximately two thirds of all extradural meningiomas. These types of meningiomas originate within the bones of the skull and thus can have a clinical presentation and radiographic differential diagnosis that is different from those for intradural meningiomas.

Primary intraosseous meningiomas are classified based on their location and histopathological characteristics. Treatment primarily involves resection with wide margins if possible. Very little literature exists regarding the use of adjuvant therapies such as radiation and chemotherapy for these tumors. In fact, the literature regarding primary intra-osseous meningiomas consists mostly of clinical case reports and case series. This literature is reviewed and summarized in this article.

Lack of B7 expression, not human leukocyte antigen expression, facilitates immune evasion by human malignant gliomas

OBJECTIVE

Lack of human leukocyte antigens and costimulatory molecules have been suggested as mechanisms by which human malignant gliomas avoid immune recognition and elimination.

METHODS

Using quantitative multiparameter flow cytometric analysis, tumor cells from patients with glioblastoma multiforme (n = 18) were examined ex vivo for the expression of human leukocyte antigen Class I and II molecules and the costimulatory molecules B7-1 and B7-2. They were compared with reactive astrocytes from peritumoral brain metastases (n = 7), and astrocytes removed during nontumor surgery (n = 5).

RESULTS

In contrast to the vast majority of solid peripheral human tumors, these results demonstrate that glioblastoma multiforme frequently express both human leukocyte antigen Class I and II molecules. Like most solid peripheral tumors, glioblastoma multiforme tumor cells express few or no B7 costimulatory molecules. Functional assays using heterogeneous ex vivo tumor preparations or pure populations of ex vivo tumor cells and microglia obtained using fluorescence-activated cell sorting indicate that CD4+ T-cells are activated by tumor cells only in the presence of exogenous B7 costimulation (provided by addition of soluble agonist anti-CD28 monoclonal antibody).

CONCLUSION

Thus, in contrast to many solid peripheral tumors, failure to present tumor antigens is not a likely impediment to immunotherapeutic strategies against malignant gliomas. Rather, immunotherapeutic strategies need to overcome low levels of B7 costimulation.

Giant cell tumor of the skull in pediatric patients

Giant cell tumors of the bone are rare, locally aggressive lesions that primarily affect the epiphyses of long bones. These tumors can occur in the skull, principally in the sphenoid and temporal bones. Symptoms of these tumors depend on their site of origin but typically include headache, pain, visual field defects, and conductive hearing loss. Histologically, these tumors consist of three cell types: osteoclast-like multinucleated giant cells; round mononuclear cells resembling monocytes; and spindle-shaped, fibroblast-like stromal cells. Radiographically, the tumors appear osteolytic and radiolucent without a sclerotic border. These tumors typically present in the third to fourth decades of life and rarely occur in patients under 20 years of age. The small number of studies of giant cell tumors of the skull has focused on the adolescent and adult populations. The authors report two cases of giant cell tumors of the skull in pediatric patients. In the first case, a 2-year-old girl presented with swelling behind the right ear. In the second case, a 7-week-old girl presented with a mass within the external auditory canal. Both patients underwent metastatic workup and biopsy procedures before resection of the tumor. Both case reports contribute to the literature of giant cell tumors of the skull by describing this condition in pediatric patients. To the authors' knowledge, these cases represent the youngest two patients with giant cell tumors of the skull yet described.

Primary colorectal tumors fail to express the proapoptotic mediator PTAG and its reexpression augments drug-induced apoptosis

Genes implicated in tumor evolution and progression, including those in apoptotic pathways, are associated with methylation-associated gene silencing in different tumor types. By exploiting differential methylation we recently isolated a novel pituitary tumor derived apoptosis gene (PTAG) that augments drug-induced apoptosis. The importance of PTAG was determined in other tumor types, and these studies show that the majority of primary colorectal tumors fail to express the PTAG gene, indicating an important role for PTAG in colorectal tumorigenesis. The effects of expression of PTAG were examined through stable transfection of the colorectal cell lines HCT116 and SW480. Expression of PTAG, per se, had no discernible effects on cell viability or cell kinetics. In contrast to these findings, in cells subject to drug challenges that engaged either a death-receptor mediated or mitochondrial pathway, all of the experiments indicated a role for PTAG in the intrinsic pathway of apoptosis. Loss of PTAG therefore contributes to a blunted apoptotic response and is likely to predispose cells toward malignant transformation and resistance to chemotherapeutic interventions.

Surgical interventions for primary central nervous system lymphoma

Early diagnosis is central to proper management of primary central nervous system lymphomas (PCNSLs). Surgical intervention hinges on initial entertainment of a diagnosis of a PCNSL, based on acute neurological presentation and neuroimaging findings. Unless there is an urgent need for surgical decompression, a biopsy to obtain a diagnosis of PCNSL is the first step in surgical management. Repeated biopsy may be necessary in patients who have received preoperative steroid therapy. Patients with PCNSL may also present with leptomeningeal involvement, resulting in the need for an Ommaya reservoir for intrathecal chemotherapy. In cases in which hydrocephalus develops, placement of a ventriculoperitoneal shunt may be necessary. Two case studies are presented to highlight the role of surgical intervention in PCNSL.

Polymorphisms in the glutathione S-transferase mu cluster are associated with tumour progression and patient outcome in colorectal cancer

Glutathione S-transferase (GST) enzymes catalyse the detoxification of by-products of reactive oxygen species and are thus important in cellular defence mechanisms. The GSTs are polymorphic with allelic variants encoding isoforms with functional differences. GST polymorphism has been associated with susceptibility and clinical outcome in patients with cancer. In this retrospective cohort, we have investigated associations between common GSTM1, GSTM3 and GSTP1 polymorphisms with factors known to influence clinical out-come and patient survival in colorectal cancer. Significant linkage disequilibrium was demonstrated between GSTM1 and GSTM3 alleles (P< or =0.001). We identified no significant associations between the GSTP1(Ile105Val105) polymorphism and any clinical outcome parameters or patient survival. However significant associations were demonstrated with mu class GSTs. Those patients who were GSTM1 null presented less frequently with poorly-differentiated tumours (P=0.038). Furthermore, patients who were GSTM3 AA were less likely to present with advanced stage tumours (T-stage, P=0.036 and Dukes' classifications, P=0.012) or distant metastases (P=0.017) when examined alone. Upon further examination of the effect of linkage disequilibrium, we found that, in GSTM1 null individuals, GSTM3 AA (compared with other GSTM3 genotypes combined) had longer disease-free survival (HR=0.54, 95% CI 0.30-0.98, P=0.044). Thus, the GSTM3 AA genotype is associated with improved prognosis especially in those with GSTM1 null. Our findings suggest that the GST mu gene cluster mediates tumour characteristics and survival in patients with colorectal cancer.

Glutathione S -transferase T1 polymorphisms are associated with outcome in colorectal cancer

Colorectal cancer (CRC) remains a significant cause of mortality accounting for approximately 10% of all deaths from malignancy in the western world. Polymorphism in the glutathione S-transferase GSTT1 gene has been associated with CRC risk in some but not all studies. In this study, we examined associations between GSTT1 genotypes and CRC risk, and prognosis in 361 cases and 881 unrelated controls. GSTT1 null was associated with a small but significant increase in risk (P = 0.0006, odds ratio (OR) = 1.65, 95% confidence interval (CI) = 1.22-2.24). GSTT1 null was also associated with a significantly younger age at diagnosis (mean 65.2 years) compared with GSTT1 A (mean 67.6 years, P = 0.031). There were no significant associations between GSTT1 genotypes and clinical factors (e.g. Dukes stage, differentiation and tumour node metastasis classification) in the total case group. However, following stratification by age (<70 versus > or =70 years at diagnosis), in the patients diagnosed <70 years of age, GSTT1 null was more common in Dukes grade A/B tumours (P = 0.046), stage T1/T2 tumours (P = 0.053) and those with a pushing margin (P = 0.066). We also identified associations between GSTT1 null and increased prevalence of host lymphocyte response, particularly in the younger patients (P = 0.036). Furthermore, GSTT1 null was associated with improved survival in younger patients (P = 0.017, hazards ratio (HR) = 0.52, 95% CI = 0.31-0.89) but poorer survival in older patients (P = 0.017, HR = 1.89, 95% CI = 1.12-3.20). We proposed a model based on the dual functionality of GSTT1 to explain these contrasting results. We suggest that the null genotype is associated with improved immune response in younger patients, but poorer detoxification in older patients. These findings may also provide an explanation for the contrasting finding of other studies on the role of this gene in CRC.

p16INK4a polymorphism: associations with tumour progression in patients with sporadic colorectal cancer

Deregulated tumour expression of p16INK4a has previously been described in association with clinical progression in sporadic colorectal cancer patients (CRC). Furthermore, p16INK4a promoter hypermethylation leading to gene silencing has been shown to occur in advanced colorectal tumours and has been associated with patient survival. p16INK4a is polymorphic, with variant alleles being associated with tumour progression in melanoma. In this study we have examined p16INK4a polymorphism as a marker of tumour progression in sporadic CRC. Polymorphic sites G/A(442), C/G(500), and C/T(540), were studied, these alleles obeyed Hardy Weinberg equilibrium in a control group, but not in the CRC cases. G/A(442) and CG(500) alleles were in linkage disequilibrium in both cases and controls. In controls the C/T(540) alleles demonstrated no linkage with either other site, whilst an association was demonstrated between C/G(500) and C/T(540) alleles in the cases (p=0.011). Furthermore, the distribution of C/T(540) genotypes was different between the groups (p=0.002). Within the CRC cases, patients with the GG(442) genotype were more commonly associated with decreased tumour differentiation (p=0.018), advancing Dukes' stage (p=0.006) and T-stage (p=0.007) than patients with the GA(442) and AA(442) genotypes. Patients with the CC(500) genotype were more commonly associated with decreased tumour differentiation (p=0.012), advancing Dukes' stage (p=0.015), and N-stage (p=0.031). No associations between patient C/T(540) genotype and clinical prognostic parameters were found. An analysis of patient tumour expression with p16INK4a genotype revealed patients with the CC(500) genotype were more commonly associated with reduced tumour p16 expression (p=0.046). In summary our data indicate that p16INK4a polymorphism is associated with tumour progression in patients with sporadic CRC.