Arteriovenous Malformations Treated With Frameless Robotic Radiosurgery Using Non-Invasive Angiography: Long-Term Outcomes of a Single Center Pilot Study

Objective

CT-guided, frameless robotic radiosurgery is a novel radiotherapy technique for the treatment of intracranial arteriovenous malformations (AVMs) that serves as an alternative to traditional catheter-angiography targeted, frame-based methods.

Methods

Patients diagnosed with AVMs who completed single fraction frameless robotic radiosurgery at Medstar Georgetown University Hospital between July 20, 2006 – March 11, 2013 were included in the present study. All patients received pre-treatment planning with CT angiogram (CTA) and MRI, and were treated using the CyberKnife radiosurgery platform. Patients were followed for at least four years or until radiographic obliteration of the AVM was observed.

Results

Twenty patients were included in the present study. The majority of patients were diagnosed with Spetzler Martin Grade II (35%) or III (35%) AVMs. The AVM median nidus diameter and nidal volume was 1.8 cm and 4.38 cc, respectively. Median stereotactic radiosurgery dose was 1,800 cGy. After a median follow-up of 42 months, the majority of patients (81.3%) had complete obliteration of their AVM. All patients who were treated to a total dose of 1800 cGy demonstrated complete obliteration. One patient treated at a dose of 2,200 cGy developed temporary treatment-related toxicity, and one patient developed post-treatment hemorrhage.

Conclusions

Frameless robotic radiosurgery with non-invasive CTA and MRI radiography appears to be a safe and effective radiation modality and serves as a novel alternative to traditional invasive catheter-angiography, frame-based methods for the treatment of intracranial AVMs. Adequate obliteration can be achieved utilizing 1,800 cGy in a single fraction, and minimizes treatment-related side effects.

A cross-sectional analysis of variables associated with morbidity and mortality in postoperative neurosurgical patients diagnosed with sepsis

BACKGROUND

Sepsis is a systemic, inflammatory response to infection associated with significant morbidity and mortality. There is a considerable lack of literature exploring sepsis in neurosurgery. We aimed to identify variables that were correlated with mortality and increased morbidity as defined by readmission and increased length of stay in postoperative neurosurgical patients that met a sepsis diagnosis.

METHODS

A retrospective chart review was conducted of 105 patients who underwent a neurosurgical operation at our institution from 2012 to 2017 who were discharged with at least one sepsis diagnosis code and who did not have a preoperative infection. We identified variables that were correlated with mortality, readmission, and increased length of stay.

RESULTS

Patients who survived were preferentially distributed towards lower ASA Physical Status Classification scores. A larger percentage of patients who did not survive had cranial surgery, whereas patients who survived were more likely to have undergone spinal surgery. Higher respiratory rates, higher maximum lactic acid levels, positive sputum cultures, and lower incoming Glasgow Coma Scores (GCS) were significantly correlated with mortality. A larger fraction of readmitted patients had positive surgical site cultures but had negative sputum cultures. Length of hospitalization was correlated with incoming GCS, non-elective operations, and Foley catheter, arterial line, central line, and endotracheal tube duration.

CONCLUSIONS

Neurosurgical postoperative patients diagnosed with sepsis may be risk stratified for mortality, readmission, and increased length of stay based on certain variables that may help direct their care. Further prospective studies are needed to explore causal relationships.

Long-Term Outcomes Following Conventionally Fractionated Stereotactic Boost for High-Grade Gliomas in Close Proximity to Critical Organs at Risk

Purpose/Objective: High-grade glioma is the most common primary malignant tumor of the CNS, with death often resulting from uncontrollable intracranial disease. Radiation dose may be limited by the tolerance of critical structures, such as the brainstem and optic apparatus. In this report, long-term outcomes in patients treated with conventionally fractionated stereotactic boost for tumors in close proximity to critical structures are presented.

Materials/Methods: Patients eligible for inclusion in this single institution retrospective review had a pathologically confirmed high-grade glioma status post-surgical resection. Inclusion criteria required tumor location within one centimeter of a critical structure, including the optic chiasm, optic nerve, and brainstem. Radiation therapy consisted of external beam radiation followed by a conventionally fractionated stereotactic boost. Oncologic outcomes and toxicity were assessed.

Results: Thirty patients eligible for study inclusion underwent resection of a high-grade glioma. The median initial adjuvant EBRT dose was 50 Gy with a median conventionally fractionated stereotactic boost of 10 Gy. All stereotactic treatments were given in 2 Gy daily fractions. Median follow-up time for the entire cohort was 38 months with a median overall survival of 45 months and 5-year overall survival of 32.5%. The median freedom from local progression was 45 months, and the 5-year freedom from local progression was 29.7%. Two cases of radiation retinopathy were identified following treatment. No patient experienced toxicity attributable to the optic chiasm, optic nerve, or brainstem and no grade 3+ radionecrosis was observed.

Conclusions: Oncologic and toxicity outcomes in high-grade glioma patients with tumors in unfavorable locations treated with conventionally fractionated stereotactic boost are comparable to those reported in the literature. This treatment strategy is appropriate for those patients with resected high-grade glioma in close proximity to critical structures.

Refractory trigeminal neuralgia treatment outcomes following CyberKnife radiosurgery

INTRODUCTION

A handful of studies have reported outcomes with CyberKnife radiosurgery (CKRS) for the treatment of trigeminal neuralgia. However, the follow-up has been short with no minimum follow-up required and have included patients with short duration of symptoms. Here we report our institutional experience on patients with a minimum follow-up of 1 year and a median follow-up of 28 months (mean 38.84 months).

METHODS

Twenty-five patients with medically and surgically intractable TN received CKRS with a mean marginal radiation dose of 64 Gy applied to an average isodose line of 86% of the affected trigeminal nerve. Follow-up data were obtained by clinical examination and telephone questionnaire. Outcome results were categorized based on the Barrow Neurological Institute (BNI) pain scale with BNI I-III considered to be good outcomes and BNI IV-V considered as treatment failure. BNI facial numbness score was used to assess treatment complications.

RESULTS

A large proportion of patients (42.9%) reported pain relief within 1 month following CKRS treatment. The mean time to recurrence of severe pain was 27.8 months (range 1-129 months). At median follow-up of 28 months (mean 38.84 months), actuarial rate of freedom from severe pain (BNI ≥ III) was 72%. At last follow-up 2 (8%) patients had freedom from any pain and no medications (BNI I) and the majority (48%) had some pain that was adequately controlled with medications. Seven patients (28%) had no response to treatment and continued to suffer from severe pain (BNI IV or V). Patient's diabetic status and overall post-treatment BNI facial numbness scores were statistically significant predictors of treatment outcomes.

CONCLUSION

CKRS represents an acceptable salvage option for with medically and/or surgically refractory patients. Even patients with severely debilitating symptoms may experience significant and sustained pain relief after CKRS. Particularly, CKRS remains an attractive option in patients who are not good surgical candidates or possibly even failed surgical therapy. This data should help in setting realistic expectations for weighing the various available treatment options.

Thoracic spine localization using preoperative placement of fiducial markers and subsequent CT. A technical report

STUDY DESIGN

A retrospective case series evaluating the use of fiducial markers with subsequent computed tomography (CT) or CT myelography for intraoperative localization.

OBJECTIVE

To evaluate the safety and utility of preoperative fiducial placement, confirmed with CT myelography, for intraoperative localization of thoracic spinal levels.

SUMMARY OF BACKGROUND DATA

Thoracic spine surgery is associated with serious complications, not the least of which is the potential for wrong-level surgery. Intraoperative fluoroscopy is often used but can be unreliable due to the patient's body habitus and anatomical variation.

METHODS

Sixteen patients with thoracic spine pathology requiring surgical intervention underwent preoperative fiducial placement at the pedicle of the level of interest in the interventional radiology suite. CT or CT myelogram was then done to evaluate fiducial location relative to the level of pathology. Surgical treatment followed at a later date in all patients.

RESULTS

All patients underwent preoperative fiducial placement and CT or CT myelography, which was done on an outpatient basis in 14 of the 16 patients. Intraoperatively, fiducial localization was easily and quickly done with intraoperative fluoroscopy leading to correct localization of spinal level in all cases. All patients had symptomatic improvement following surgery. There were no complications from preoperative localization or operative intervention.

CONCLUSIONS

Preoperative placement of fiducial markers confirmed with a CT or CT myelogram allows for reliable and fast intraoperative localization of the spinal level of interest with minimal risks and potential complications to the patient. In most cases, a noncontrast CT should be sufficient. This should be an equally reliable means of localization while further decreasing potential for complications. CT myelography should be reserved for pathology that is not evident on noncontrast CT. Accuracy of localization is independent of variations in rib number or vertebral segmentation. The technique is a safe, reliable, and rapid means of localizing spinal level during surgery.

Rationale for stereotactic body radiation therapy in treating patients with oligometastatic hormone-naïve prostate cancer

Despite advances in treatment for metastatic prostate cancer, patients eventually progress to castrate-resistant disease and ultimately succumb to their cancer. Androgen deprivation therapy (ADT) is the standard treatment for metastatic prostate cancer and has been shown to improve median time to progression and median survival time. Research suggests that castrate-resistant clones may be present early in the disease process prior to the initiation of ADT. These clones are not susceptible to ADT and may even flourish when androgen-responsive clones are depleted. Stereotactic body radiation therapy (SBRT) is a safe and efficacious method of treating clinically localized prostate cancer and metastases. In patients with a limited number of metastatic sites, SBRT may have a role in eliminating castrate-resistant clones and possibly delaying progression to castrate-resistant disease.

Five fraction image-guided radiosurgery for primary and recurrent meningiomas

PURPOSE

Benign tumors that arise from the meninges can be difficult to treat due to their potentially large size and proximity to critical structures such as cranial nerves and sinuses. Single fraction radiosurgery may increase the risk of symptomatic peritumoral edema. In this study, we report our results on the efficacy and safety of five fraction image-guided radiosurgery for benign meningiomas.

MATERIALS/METHODS

Clinical and radiographic data from 38 patients treated with five fraction radiosurgery were reviewed retrospectively. Mean tumor volume was 3.83 mm(3) (range, 1.08-20.79 mm(3)). Radiation was delivered using the CyberKnife, a frameless robotic image-guided radiosurgery system with a median total dose of 25 Gy (range, 25-35 Gy).

RESULTS

The median follow-up was 20 months. Acute toxicity was minimal with eight patients (21%) requiring a short course of steroids for headache at the end of treatment. Pre-treatment neurological symptoms were present in 24 patients (63.2%). Post treatment, neurological symptoms resolved completely in 14 patients (58.3%), and were persistent in eight patients (33.3%). There were no local failures, 24 tumors remained stable (64%) and 14 regressed (36%). Pre-treatment peritumoral edema was observed in five patients (13.2%). Post-treatment asymptomatic peritumoral edema developed in five additional patients (13.2%). On multivariate analysis, pre-treatment peritumoral edema and location adjacent to a large vein were significant risk factors for radiographic post-treatment edema (p = 0.001 and p = 0.026 respectively).

CONCLUSION

These results suggest that five fraction image-guided radiosurgery is well tolerated with a response rate for neurologic symptoms that is similar to other standard treatment options. Rates of peritumoral edema and new cranial nerve deficits following five fraction radiosurgery were low. Longer follow-up is required to validate the safety and long-term effectiveness of this treatment approach.

Fiducial-free CyberKnife stereotactic body radiation therapy (SBRT) for single vertebral body metastases: acceptable local control and normal tissue tolerance with 5 fraction approach

This retrospective analysis examines the local control and toxicity of five-fraction fiducial-free CyberKnife stereotactic body radiation therapy (SBRT) for single vertebral body (VB) metastases. All patients had favorable performance status (ECOG 0-1), oligometastatic disease, and no prior spine irradiation. A prescribed dose of 30-35 Gy was delivered in five fractions to the planning target volume (PTV) using the CyberKnife with X-sight spine tracking. Suggested maximum spinal cord and esophagus point doses were 30 and 40 Gy, respectively. A median 30 Gy (IQR, 30-35 Gy) dose was delivered to a median prescription isodose line of 70% (IQR, 65-77%) to 20 patients. At 34 months median follow-up (IQR, 25-40 months) for surviving patients, the 1- and 2-year Kaplan-Meier local control estimates were 80 and 73%, respectively. Two of the five local failures were infield in patients who had received irradiation to the gross tumor volume and three were paravertebral failures just outside the PTV in patients with prior corpectomy. No local failures occurred in patients who completed VB radiation alone. The 1- and 2-year Kaplan-Meier overall survival estimates were 80 and 57%, respectively. Most deaths were attributed to metastatic disease; one death was attributed to local recurrence. The mean maximum point doses were 26.4 Gy (SD, 5.1 Gy) to the spinal cord and 29.1 Gy (SD, 8.9 Gy) to the esophagus. Patients receiving maximum esophagus point doses greater than 35 Gy experienced acute dysphagia (Grade I/II). No spinal cord toxicity was documented. Five-fraction fiducial-free CyberKnife SBRT is an acceptable treatment option for newly diagnosed VB metastases with promising local control rates and minimal toxicity despite the close proximity of such tumors to the spinal cord and esophagus. A prospective study aimed at further enhancing local control by targeting the intact VB and escalating the total dose is planned.

CyberKnife enhanced conventionally fractionated chemoradiation for high grade glioma in close proximity to critical structures

Introduction

With conventional radiation technique alone, it is difficult to deliver radical treatment (≥ 60 Gy) to gliomas that are close to critical structures without incurring the risk of late radiation induced complications. Temozolomide-related improvements in high-grade glioma survival have placed a higher premium on optimal radiation therapy delivery. We investigated the safety and efficacy of utilizing highly conformal and precise CyberKnife radiotherapy to enhance conventional radiotherapy in the treatment of high grade glioma.

Methods

Between January 2002 and January 2009, 24 patients with good performance status and high-grade gliomas in close proximity to critical structures (i.e. eyes, optic nerves, optic chiasm and brainstem) were treated with the CyberKnife. All patients received conventional radiation therapy following tumor resection, with a median dose of 50 Gy (range: 40 - 50.4 Gy). Subsequently, an additional dose of 10 Gy was delivered in 5 successive 2 Gy daily fractions utilizing the CyberKnife^® image-guided radiosurgical system. The majority of patients (88%) received concurrent and/or adjuvant Temozolmide.

Results

During CyberKnife treatments, the mean number of radiation beams utilized was 173 and the mean number of verification images was 58. Among the 24 patients, the mean clinical treatment volume was 174 cc, the mean prescription isodose line was 73% and the mean percent target coverage was 94%. At a median follow-up of 23 months for the glioblastoma multiforme cohort, the median survival was 18 months and the two-year survival rate was 37%. At a median follow-up of 63 months for the anaplastic glioma cohort, the median survival has not been reached and the 4-year survival rate was 71%. There have been no severe late complications referable to this radiation regimen in these patients.

Conclusion

We utilized fractionated CyberKnife radiotherapy as an adjunct to conventional radiation to improve the targeting accuracy of high-grade glioma radiation treatment. This technique was safe, effective and allowed for optimal dose-delivery in our patients. The value of image-guided radiation therapy for the treatment of high-grade gliomas deserves further study.

Surgical resection of intrinsic insular tumors: complication avoidance

OBJECT

Surgical resection of tumors located in the insular region is challenging for neurosurgeons, and few have published their surgical results. The authors report their experience with intrinsic tumors of the insula, with an emphasis on an objective determination of the extent of resection and neurological complications and on an analysis of the anatomical characteristics that can lead to suboptimal outcomes.

METHODS

Twenty-two patients who underwent surgical resection of intrinsic insular tumors were retrospectively identified. Eight tumors (36%) were purely insular, eight (36%) extended into the temporal pole, and six (27%) extended into the frontal operculum. A transsylvian surgical approach, combined with a frontal opercular resection or temporal lobectomy when necessary, was used in all cases. Five of 13 patients with tumors located in the dominant hemisphere underwent craniotomies while awake. The extent of tumor resection was determined using volumetric analyses. In 10 patients, more than 90% of the tumor was resected; in six patients, 75 to 90% was resected; and in six patients, less than 75% was resected. No patient died within 30 days after surgery. During the immediate postoperative period, the neurological conditions of 14 patients (64%) either improved or were unchanged, and in eight patients (36%) they worsened. Deficits included either motor or speech dysfunction. At the 3-month follow-up examination, only two patients (9%) displayed permanent deficits. Speech and motor dysfunction appeared to result most often from excessive opercular retraction and manipulation of the middle cerebral artery (MCA), interruption of the lateral lenticulostriate arteries (LLAs), interruption of the long perforating vessels of the second segment of the MCA (M2), or violation of the corona radiata at the superior aspect of the tumor. Specific methods used to avoid complications included widely splitting the sylvian fissure and identifying the bases of the periinsular sulci to define the superior and inferior resection planes, identifying early the most lateral LLA to define the medial resection plane, dissecting the MCA before tumor resection, removing the tumor subpially with preservation of all large perforating arteries arising from posterior M2 branches, and performing craniotomy with brain stimulation while the patient was awake.

CONCLUSIONS

A good understanding of the surgical anatomy and an awareness of potential pitfalls can help reduce neurological complications and maximize surgical resection of insular tumors.