The Effect of Pain Reduction during Headframe Fixation for Stereotactic Radiosurgery by the Preceded Local Anesthesia under the Needle Cap Guidance

Background

Gamma knife radiosurgery (GKRS) has become a major alternative in the neurosurgical field. However, many patients complained of considerable discomfort during the fixation of rigid headframe. This study investigated whether our modified procedure could reduce fixation-related pain.

Methods

Sixty-six patients who underwent GKRS were enrolled in this study. Thirty-one patients (Group A) underwent the conventional subcutaneous infiltration technique, and 35 patients (Group B) did the modified procedure. In group A, the headframe was held in position by an assistant, and local anesthetics were injected subcutaneously using a 23-gauge spinal needle at pinning sites. Subsequently, pins were applied according to measurements based on spinal needle depth. In group B, with the frame held in position by an assistant, pin sites were marked with a surgical pen under the guidance of needle cap placed on the pin holes. The head frame was then removed, and local anesthetics were injected subcutaneously and periosteally at each marked pin site using a 26-gauge needle. The headframe was then repositioned 5 minutes after local infiltration, and pins were applied according to measurements based on spinal needle depth. To evaluate pain severity during procedures, visual analogue scale (VAS) scores were recorded during local infiltration and frame placement with pins. The pain scores of the two groups were analyzed statistically.

Results

Group B had a significantly lower VAS score during frame placement than group A (7.26 vs. 3.61; p<0.001), and mean VAS score at local infiltration was also significantly lower in group B (4.74 vs. 3.74; p=0.008).

Conclusion

Patients in group B experienced significantly less pain than those in group A during pin placement. Pre-fixation time advanced local anesthesia might reduce pain during stereotactic procedures, and the use of a 26-gauge needle appeared in less pain during local infiltration.

Radiosurgical techniques for the treatment of brain neoplasms: A short review

Radiotherapy has long been used as an adjunct to neurosurgery for the treatment of malignant and benign intracranial tumors and other intracranial lesions. Intracranial tumors can be irradiated in three different ways: I) fractional radiotherapy, II) stereotactic radiotherapy and III) stereotactic radiosurgery. The third is most often by means of a gamma knife or a specially designed linear accelerator. Additionally, radiosurgery is increasingly used in combination with systemic therapy to treat metastases.

Preliminary results of contrast-enhanced sonography in the evaluation of the response of uveal melanoma to gamma-knife radiosurgery

PURPOSE

Our aim was to prospectively analyze the use of contrast-enhanced ultrasound (CEUS) in the quantitative assessment of the response of uveal melanoma (UM) to gamma-knife radiosurgery (GKR), investigating whether changes in tumor vascularization precede thickness reduction, which on average occurs at 12 months after GKR.

METHODS

Ten patients with UM treated with GKR underwent sonography (US) and CEUS at baseline and at 3, 6, and 12 months after GKR. The transverse diameter, thickness, and quantitative parameters of the UM (ie, area under the curve in the wash-in phase, wash-in perfusion index, peak enhancement, and wash-in rate) were calculated by using dedicated software and compared by using Wilcoxon's signed-rank test.

RESULTS

The mean tumor thickness on US was significantly less at both 6 (6.6 mm) and 12 months after GKR (5.8 mm) than it was at baseline (8.3 mm; p < 0.05, both comparisons). Compared with baseline data, the median flow quantitative parameters on CEUS were significantly changed as follows: the peak enhancement (in arbitrary units [au]) at baseline was 5 × 10(6) ; 6 months after GKR, it was 2 × 10(1) (p < 0.05), and 12 months after GKR, it was 4 × 10(1) (p < 0.05). The wash-in rate (in au) at baseline was 1 × 10(6) ; 6 months after GKR, it was 2.1 (p < 0.05), and 12 months after GKR, it was 9.3 (p < 0.05). The wash-in perfusion index (in au) at baseline was 2 × 10(7) ; 6 months after GKR, it was 7 × 10(1) (p < 0.05), and 12 months after GKR, it was 1 × 10(2) (p < 0.05). The area under the curve during the wash-in phase (in au) at baseline was 1 × 10(8) ; 12 months after GKR, it was reduced to 6 × 10(2) (p < 0.05).

CONCLUSIONS

At 6 months after GKR, a reduction of tumor thickness, as detected on US, occurred in 6 of the 10 patients, whereas a reduction in all the quantitative parameters measured on CEUS occurred in all 10 patients. However, a larger population is needed to investigate whether CEUS could become the first-choice technique for monitoring the response of UM to GKR.

Intrafraction variations in linac-based image-guided radiosurgery of intracranial lesions

PURPOSE

This study investigated image-guided patient positioning during frameless, mask-based, single-fraction stereotactic radiosurgery of intracranial lesions and intrafractional translational and rotational variations in patient positions.

PATIENTS AND METHODS

A non-invasive head and neck thermoplastic mask was used for immobilization. The Exactrac/Novalis Body system (BrainLAB AG, Germany) was used for kV X-ray imaging guided positioning. Intrafraction displacement data, obtained by imaging after each new table position, were evaluated.

RESULTS

There were 269 radiosurgery treatments performed on 190 patients and a total of 967 setups within different angles. The first measured error after each table rotation (mean 2.6) was evaluated (698 measurements). Intrafraction translational errors were (1 standard deviation [SD]) on average 0.8, 0.8, and 0.7mm for the left-right, superior-inferior, and anterior-posterior directions, respectively, with a mean 3D-vector of 1.0mm (SD 0.9mm) and a range from -5mm to +5mm. On average, 12%, 3%, and 1% of the translational deviations exceeded 1, 2, and 3mm, respectively, in the three directions.

CONCLUSION

The range of intrafraction patient motion in frameless image-guided stereotactic radiosurgery is often not fully mapped by pre- and post-treatment imaging. In the current study, intrafraction motion was assessed by performing measurements at several time points during the course of stereotactic radiosurgery. It was determined that 12% of the intrafraction values in the three dimensions are above 1mm, the usual safety margin applied in stereotactic radiosurgery.

Seizures in low-grade gliomas: natural history, pathogenesis, and outcome after treatments

Seizures represent a common symptom in low-grade gliomas; when uncontrolled, they significantly contribute to patient morbidity and negatively impact quality of life. Tumor location and histology influence the risk for epilepsy. The pathogenesis of tumor-related epilepsy is multifactorial and may differ among tumor histologies (glioneuronal tumors vs diffuse grade II gliomas). Gross total resection is the strongest predictor of seizure freedom in addition to clinical factors, such as preoperative seizure duration, type, and control with antiepileptic drugs (AEDs). Epilepsy surgery may improve seizure control. Radiotherapy and chemotherapy with alkylating agents (procarbazine + CCNU+ vincristine, temozolomide) are effective in reducing the frequency of seizures in patients with pharmacoresistant epilepsy. Newer AEDs (levetiracetam, topiramate, lacosamide) seem to be better tolerated than the old AEDs (phenobarbital, phenytoin, carbamazepine), but there is lack of evidence regarding their superiority in terms of efficacy.

Intracranial metastatic neuroblastoma treated with gamma knife stereotactic radiosurgery: report of two novel cases

Intracranial metastasis of neuroblastoma (IMN) is associated with poor survival. No curative therapy for the treatment of IMN currently exists. Unfractionated radiotherapy may be beneficial in the treatment of IMN given the known radiosensitivity of neuroblastoma as well as its proclivity to metastasize as discrete lesions. We present two patients with IMN treated with Gamma Knife stereotactic radiosurgery (SRS). Single-fraction radiotherapy yielded temporary reduction of tumor burden and stability of disease in both patients. SRS may be a useful palliative tool in the treatment of IMN and expands the overall treatment options for this disease.

γ knife surgery versus reoperation for recurrent glioblastoma multiforme

BACKGROUND

The optimal management of patients with recurrent glioblastoma multiforme (GBM) is a subject of controversy. These patients may be candidates for both reoperation and/or gamma knife surgery (GKS). Few studies have addressed the role of GKS for relapsing gliomas, and the results have not been compared with reoperation. To validate the efficacy and safety of GKS, we compared the survival and complication rates of GKS and reoperation for recurrent GBMs.

METHODS

This study retrospectively reviewed 77 consecutive patients with histopathologically confirmed GBMs retreated for recurrent GBM between 1996 and 2007. Thirty-two patients underwent GKS, 26 reoperation and 19 both procedures.

RESULTS

The median time from the second intervention to tumor progression was longer after GKS than after resection, P = 0.009. Median survival after retreatment was 12 months for the 51 patients receiving GKS compared with 6 months for reoperation only (P = 0.001, hazard ratio [HR] 2.4), and 19 months versus 16 months from the time of primary diagnosis (P = 0.021, HR 1.8). A multivariate analysis adjusted for possible confounding factors (tumor volume, recursive partitioning analysis class, neurological deficits, time to recurrence, adjuvant therapy, and tumor location) showed significantly longer survival for patients treated with GKS, both from retreatment (P = 0.013, HR 4.1) and from primary diagnosis (P = 0.002, HR 5.8). The adjusted results were still significant after separate analysis according to tumor volume <5 mL, 5 to 20 mL, and >20 mL. The complications rate was 9.8% after GKS and 25.2% after reoperation.

CONCLUSIONS

GKS may be an alternative to open surgery for small GBMs at the time of recurrences, with a significantly lower complication rate and a possible survival benefit compared with reoperation.

Combining brain diagnosis and therapy in a single strategy: the safety, reliability, and cost implications using same-day versus separate-day stereotactic procedures

BACKGROUND

A therapeutic radiosurgery procedure usually follows a separate diagnostic stereotactic procedure after days or weeks.

OBJECTIVES

To define the clinical reliability, safety, and cost implications of same-day diagnostic stereotactic biopsy and therapeutic radiosurgery.

METHODS

During an 8-year interval, 26 patients underwent stereotactic brain biopsy followed by immediate therapeutic stereotactic radiosurgery in a single-day combined procedure. The intraoperative diagnosis was determined using standard histopathological techniques. Diagnostic accuracy, hospital costs, and contribution margins associated with this treatment strategy were compared to those of 26 case-matched patients (controls) who underwent a stereotactic diagnostic procedure followed by a separate-day outpatient SRS procedure within 6 weeks during the same time interval.

RESULTS

The intraoperative diagnosis correlated with the final histopathological diagnosis in 96% of the patients. Biopsy-related morbidity did not occur in this series. The mean total costs of same-day patients was significantly lower than the costs of patients who had two-stage procedures (USD 9,077 ± 2,366 vs. 11,284 ± 3,025; p = 0.008). The net contribution to the hospital margin of USD 13,736 was not significantly different between the two management strategies.

CONCLUSIONS

The advantages of the same-day approach included a single stereotactic head frame application, reduced total admission time, consecutive histopathological diagnosis and therapy in a single hospital admission, and reduced total hospital costs. For patients who are highly suspected to have a brain tumor for which SRS is likely to be an effective therapeutic strategy, same-day diagnostic stereotactic biopsy followed by therapeutic SRS proved to be a safe, reliable, and cost-effective management strategy.

Cranial irradiation leads to acute and persistent neuroinflammation with delayed increases in T-cell infiltration and CD11c expression in C57BL/6 mouse brain

Radiotherapy is commonly employed to treat cancers of the head and neck and is increasingly used to treat other central nervous system (CNS) disorders. Exceeding the radiation tolerance of normal CNS tissues can result in sequelae contributing to patient morbidity and mortality. Animal studies and clinical experience suggest that neuroinflammation plays a role in the etiology of these effects; however, detailed characterization of this response has been lacking. Therefore, a dose-time investigation of the neuroinflammatory response after single-dose cranial irradiation was performed using C57BL/6 mice. Consistent with previous reports, cranial irradiation resulted in multiphasic inflammatory changes exemplified by increased transcript levels of inflammatory cytokines, along with glial and endothelial cell activation. Cranial irradiation also resulted in acute infiltration of neutrophils and a delayed increase in T cells, MHC II-positive cells, and CD11c-positive cells seen first at 1 month with doses ≥ 15 Gy. CD11c-positive cells were found almost exclusively in white matter and expressed MHC II, suggesting a "mature" dendritic cell phenotype that remained elevated out to 1 year postirradiation. Our results indicate that cranial irradiation leads to persistent neuroinflammatory changes in the C57BL/6 mouse brain that includes unique immunomodulatory cell populations.

Epilepsy and brain tumors

PURPOSE OF REVIEW

To present an overview of the recent findings in pathophysiology and management of epileptic seizures in patients with brain tumors.

RECENT FINDINGS

Low-grade gliomas are the most epileptogenic brain tumors. Regarding pathophysiology, the role of peritumoral changes [hypoxia and acidosis, blood-brain barrier (BBB) disruption, increase or decrease of neurotransmitters and receptors] are of increasing importance. Tumor-associated epilepsy and tumor growth could have some common molecular pathways. Total/subtotal surgical resection (with or without epilepsy surgery) allows a seizure control in a high percentage of patients. Radiotherapy and chemotherapy as well have a role. New antiepileptic drugs are promising, both in terms of efficacy and tolerability. The resistance to antiepileptic drugs is still a major problem: new insights into pathogenesis are needed to develop strategies to manipulate the pharmakoresistance.

SUMMARY

Epileptic seizures in brain tumors have been definitely recognized as one of the major problems in patients with brain tumors, and need specific and multidisciplinary approaches.

Precision of navigated stereotactic probe implantation into the brainstem

OBJECT

The indications for stereotactic biopsies or implantation of probes for local chemotherapy in diffuse brainstem tumors have recently come under debate. The quality of performing these procedures significantly depends on the precision of the probes' placement in the brainstem. The authors evaluated the precision of brainstem probe positioning using a navigated frameless stereotactic system in an experimental setting.

METHODS

Using the VarioGuide stereotactic system, 33 probes were placed into a specially designed model filled with agarose. In a second experimental series, 8 anatomical specimens were implanted with a total of 32 catheters into the pontine brainstem using either a suboccipital or a precoronal entry point. Before intervention in both experimental settings, a thin-sliced CT scan for planning was obtained and fused to volumetric T1-weighted MR imaging data. After the probe positioning procedures, another CT scan and an MR image were obtained to compare the course of the catheters versus the planned trajectory. The deviation between the planned and the actual locations was measured to evaluate the precision of the navigated intervention.

RESULTS

Using the VarioGuide system, mean total target deviations of 2.8 +/- 1.2 mm on CT scanning and 3.1 +/- 1.2 mm on MR imaging were detected with a mean catheter length of 151 +/- 6.1 mm in the agarose model. The catheter placement in the anatomical specimens revealed mean total deviations of 1.95 +/- 0.6 mm on CT scanning and 1.8 +/- 0.7 mm on MR imaging for the suboccipital approach and a mean catheter length of 59.5 +/- 4.1 mm. For the precoronal approach, deviations of 2.2 +/- 1.2 mm on CT scanning and 2.1 +/- 1.1 mm on MR imaging were measured (mean catheter length 85.9 +/- 4.7 mm).

CONCLUSIONS

The system-based deviation of frameless stereotaxy using the VarioGuide system reveals good probe placement in deep-seated locations such as the brainstem. Therefore, the authors believe that the system can be accurately used to conduct biopsies and place probes in patients with brainstem lesions.

Predictors of efficacy after stereotactic radiosurgery for medial temporal lobe epilepsy

BACKGROUND

Stereotactic radiosurgery (RS) is a promising treatment for intractable medial temporal lobe epilepsy (MTLE). However, the basis of its efficacy is not well understood.

METHODS

Thirty patients with MTLE were prospectively randomized to receive 20 or 24 Gy 50% isodose RS centered at the amygdala, 2 cm of the anterior hippocampus, and the parahippocampal gyrus. Posttreatment MRI was evaluated quantitatively for abnormal T2 hyperintensity and contrast enhancement, mass effect, and qualitatively for spectroscopic and diffusion changes. MRI findings were analyzed for potential association with radiation dose and seizure remission (Engel Ib or better outcome).

RESULTS

Despite highly standardized dose targeting, RS produced variable MRI alterations. In patients with multiple serial imaging, the appearance of vasogenic edema occurred approximately 9-12 months after RS and correlated with onset of seizure remission. Diffusion and spectroscopy-detected alterations were consistent with a mechanism of temporal lobe radiation injury mediated by local vascular insult and neuronal loss. The degree of these early alterations at the peak of radiographic response was dose-dependent and predicted long-term seizure remission in the third year of follow-up. Radiographic changes were not associated with neurocognitive impairments.

CONCLUSIONS

Temporal lobe stereotactic radiosurgery resulted in significant seizure reduction in a delayed fashion which appeared to be well-correlated with structural and biochemical alterations observed on neuroimaging. Early detected changes may offer prognostic information for guiding management.

High-precision radiosurgical dose delivery by interlaced microbeam arrays of high-flux low-energy synchrotron X-rays

Microbeam Radiation Therapy (MRT) is a preclinical form of radiosurgery dedicated to brain tumor treatment. It uses micrometer-wide synchrotron-generated X-ray beams on the basis of spatial beam fractionation. Due to the radioresistance of normal brain vasculature to MRT, a continuous blood supply can be maintained which would in part explain the surprising tolerance of normal tissues to very high radiation doses (hundreds of Gy). Based on this well described normal tissue sparing effect of microplanar beams, we developed a new irradiation geometry which allows the delivery of a high uniform dose deposition at a given brain target whereas surrounding normal tissues are irradiated by well tolerated parallel microbeams only. Normal rat brains were exposed to 4 focally interlaced arrays of 10 microplanar beams (52 µm wide, spaced 200 µm on-center, 50 to 350 keV in energy range), targeted from 4 different ports, with a peak entrance dose of 200Gy each, to deliver an homogenous dose to a target volume of 7 mm³ in the caudate nucleus. Magnetic resonance imaging follow-up of rats showed a highly localized increase in blood vessel permeability, starting 1 week after irradiation. Contrast agent diffusion was confined to the target volume and was still observed 1 month after irradiation, along with histopathological changes, including damaged blood vessels. No changes in vessel permeability were detected in the normal brain tissue surrounding the target. The interlacing radiation-induced reduction of spontaneous seizures of epileptic rats illustrated the potential pre-clinical applications of this new irradiation geometry. Finally, Monte Carlo simulations performed on a human-sized head phantom suggested that synchrotron photons can be used for human radiosurgical applications. Our data show that interlaced microbeam irradiation allows a high homogeneous dose deposition in a brain target and leads to a confined tissue necrosis while sparing surrounding tissues. The use of synchrotron-generated X-rays enables delivery of high doses for destruction of small focal regions in human brains, with sharper dose fall-offs than those described in any other conventional radiation therapy.

Stereotactic radiosurgery and stereotactic radiotherapy in the treatment of skull base meningiomas

Meningiomas are the most common nonglial brain tumors. They tend to be slow growing and benign and can reach substantial sizes before becoming symptomatic. Complete surgical resection of intracranial meningiomas remains the treatment of choice. Location of a meningioma within the cranial vault may make complete surgical resection unlikely; tumors arising from the dura of the skull base are particularly challenging. Advances in radiation therapy, including stereotactic techniques, can expand the options for treatment available in these situations. They may be used as adjuncts to surgery or as alternative modalities in the treatment of these complex tumors.