Complications of Gamma Knife surgery: an early report from 2 Canadian centers

Severe pneumocranium after gamma knife stereotactic radiosurgery for brain metastasis: A case report and literature review

RATIONALE

Gamma knife stereotactic radiosurgery (GKRS) is a recognized safe and effective treatment for brain metastasis; however, some complications can present significant clinical challenges. This case report highlights a rare occurrence of cerebrospinal fluid (CSF) leakage and pneumocranium following GKRS, emphasizing the need for awareness and prompt management of these complications.

PATIENT CONCERNS

A 35-year-old male with a history of malignant neoplasm of the lip in 2015 and perineural spread of malignancy into the left cavernous sinus was treated with GKRS in 2017. The patient was admitted emergently 39 days after discharge due to persistent headache and dizziness.

DIAGNOSES

Brain computed tomography (CT) revealed diffuse bilateral pneumocranium alongside an observation of CSF leakage.

INTERVENTIONS

A surgical procedure involving a left frontal-temporal craniotomy was performed to excise a residual skull base tumor and repair the dura, guided by a navigator system. The conclusive pathological assessment revealed the presence of squamous cell carcinoma markers.

OUTCOMES

The patient exhibited excellent tolerance to the entire procedure and experienced a prompt and uneventful recovery process. After surgery, the symptoms alleviated and CSF leak stopped. The follow-up image showed the pneumocranium resolved.

LESSONS

Pneumocranium due to early-stage post-GKRS is uncommon. The rapid tumor shrinkage and timing of brain metastasis spreading through the dura can lead to CSF leak and pneumocranium. We reviewed current treatment options and presented a successful craniotomy-based dura repair case.

Hypofractionated frameless gamma knife radiosurgery for large metastatic brain tumors

Hypofractionated stereotactic radiosurgery has become an alternative for metastatic brain tumors (METs). We aimed to analyze the efficacy and safety of frameless hypofractionated Gamma Knife radiosurgery (hfGKRS) in the management of unresected, large METs. All patients who were managed with hfGKRS for unresected, large METs (> 4 cm³) between June 2017 and June 2020 at a single center were reviewed in this retrospective study. Local control (LC), progression-free survival (PFS), overall survival (OS), and toxicities were investigated. A total of 58 patients and 76 METs with regular follow-up were analyzed. LC rate was 98.5% at six months, 96.0% at one year, and 90.6% at 2 years during a median follow-up of 12 months (range, 2-37). The log-rank test indicated no difference in the distribution of LC for any clinical or treatment variable. PFS was 86.7% at 6 months, 66.6% at 1 year, and 58.5% at 2 years. OS was 81% at 6 months, 63.6% at one year, and 50.7% at 2 years. On the log-rank test, clinical parameters such as control status of primary cancer, presence of extracranial metastases, RTOG-RPA class, GPA group, and ds-GPA group were significantly associated with PFS and OS. Patients presented with grade 1 (19.0%), grade 2 (3.5%) and grade 3 (5.2%) side effects. Radiation necrosis was not observed in any patients. Our current results suggest that frameless hfGKRS for unresected, large METs is a rational alternative in selected patients with promising results.

Labiomental sensation after segmental mandibulectomy and inferior alveolar nerve preservation for osteoradionecrosis

Advanced mandibular osteoradionecrosis requires a segmental mandibulectomy with reconstruction using a free fibular flap. The conservation of labiomental sensation by lateralization of the inferior alveolar nerve is unusual during a segmental mandibulectomy. A protocol for the evaluation of labiomental sensation has been created for the clinical follow-up of operated patients. The patients included were patients with mandibular osteoradionecrosis who underwent a segmental mandibulectomy with reconstruction by free fibular flap and whose pre-operative labiomental sensation was preserved. All patients were followed-up by the same examiner and operated on by the same surgeon. The neuro-sensitive examination analyses the different forms of sensation at 1 week and at 12 months postoperatively. Between May 2017 and May 2018, 3 consecutive patients were assessed. The results of the labiomental sensitive evaluation using our evaluation protocol attest to the preservation of labiomental sensation. The operating time was increased by an average of 35 min per surgical procedure. The conservation and re-routing of the inferior alveolar nerve in segmental mandibulectomy with fibula free flap reconstruction in patients with osteoradionecrosis allows for the preservation of labiomental sensation, which improves the quality of life of patients. Our protocol can be used in all surgical procedure that affect sensibility.

Frameless Fractionated Gamma Knife Radiosurgery with ICON™ for Large Metastatic Brain Tumors

BACKGROUND

Recently, a new generation of gamma knife radiosurgery (GKRS) equipped with a frameless immobilization system has encouraged the use of fractionated GKRS as an increasingly favorable treatment option. We investigated the preliminary outcome of efficacy and toxicity associated with frameless fractionated gamma knife radiosurgery (FF GKRS) for the treatment of large metastatic brain tumors.

METHODS

Fifteen patients with 17 lesions were treated using FF GKRS and included in this study, because of the large tumor size of more than 10 cm³. FF GKRS was performed based on a thermoplastic mask system for 3 to 5 consecutive days.

RESULTS

The mean duration of clinical follow-up was 12 months (range, 4-24), and the local control rate was 100%. Tumor volume decreased in 13 lesions (76.5%), and remained stable in 4 lesions (23.5%). One patient was classified as new lesion development because of the occurrence of leptomeningeal seeding regardless of the tumor volume change. Compared with the initial volume at the time of FF GKRS, tumor volume change at the last follow-up was 62.32% ± 29.80%. Cumulative survival rate at 12 months was 93.3% ± 6.4%. One patient died during the follow-up period because of the progression of the primary disease. No patient showed radiation necrosis on the follow-up images.

CONCLUSION

Daily FF GKRS by gamma knife ICON™ revealed satisfactory tumor control rate and low morbidity, despite the short follow-up period. Further prospective studies and a longer follow-up of a large cohort of patients diagnosed with brain metastases are required to elucidate the effect of FF GKRS in brain metastases.

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.

Shared decision making and decisional conflict in the Management of Vestibular Schwannoma: a prospective cohort study

Background

Patients with vestibular schwannomas (VS) are faced with complex management decisions. Watchful waiting, surgical resection, and radiation are all viable options with associated risks and benefits. We sought to determine if patients with VS experience decisional conflict when deciding between surgery or non-surgical management, and factors influencing the degree of decisional conflict.

Methods

A prospective cohort study in two tertiary ambulatory skull-base clinics was performed. Patients with newly diagnosed or newly growing vestibular schwannomas were recruited. Patients were given a demographic form and the decisional conflict scale (DCS), a validated measure to assess the degree of uncertainty when making medical decisions. The degree of shared decision making (SDM) experienced by the patient and physician were assessed via the SDM-Q-10 and SDM-Q-Doc questionnaires, respectively. Non-parametric statistics were used. Questionnaires and demographic information were correlated with DCS using Spearman correlation coefficient and Mann-Whitney U. Logistic regression was performed to determine factors independently associated with DCS scores.

Results

Seventy-seven patients participated (55% female, aged 37–81 years); VS ranged in size from 2 mm–50 mm. Significant decisional conflict (DCS score 25 or greater) was experienced by 17 (22%) patients. Patients reported an average SDM-Q-10 score of 86, indicating highly perceived level of SDM. Physician and patient SDM scores were weakly correlated (p = 0.045, Spearman correlation coefficient 0.234). DCS scores were significantly negatively correlated with a decision to pursue surgery, presence of a trainee, and higher SDM-Q-10 score. DCS was higher with female gender. Using logistic regression, the SDM-Q-10 score was the only variable associated with significantly reduced DCS.

Conclusions

About one fifth of patients deciding how to manage their vestibular schwannoma experienced a significant degree of decisional conflict. Involving the patients in the process through shared decision-making significantly reduced the degree of uncertainty patients experienced.

Completion of Gamma Knife radiosurgery for AVM treatment after unplanned interruption-technical note

BACKGROUND AND IMPORTANCE

Gamma Knife radiosurgery is an established technique for non-urgent treatment of various intracranial pathologies. Intra-procedural dislodgement of the stereotactic frame is an uncommon occurrence that could lead to abortion of ongoing treatment and necessitate more invasive treatment strategies.

CLINICAL PRESENTATION

In this case report, we describe a novel method for resumption of Gamma Knife treatment after an unplanned intra-procedural interruption. The case example involves a radiosurgical treatment of a Spetzler-Martin grade I arteriovenous malformation.

CONCLUSION

Our technique involves integration of scans and coordinate systems from two imaging sessions using the composite isodose line to resolve translational differences, thereby limiting delivery of remaining shots to the untreated region of the lesion. MRI follow-up at 13 months showed a reduction in the nidus size with no evidence of any radiation injury to the surrounding brain parenchyma. We believe this technique will allow care teams to effectively salvage interrupted Gamma Knife procedures and reduce progression to more invasive treatment options.

Focused Ultrasound for Essential Tremor: Review of the Evidence and Discussion of Current Hurdles

Background

While there is no breakthrough progress in the medical treatment of essential tremor (ET), in the past decades several remarkable achievements happened in the surgical field, such as radiofrequency thalamotomy, thalamic deep brain stimulation, and gamma knife thalamotomy. The most recent advance in this area is magnetic resonance-guided focused ultrasound (MRgFUS).

Methods

The purpose of this review is to discuss the new developments and trials of MRgFUS in the treatment of ET and other tremor disorders.

Results

MRgFUS is an incisionless surgery performed without anesthesia and ionizing radiation (no risk of cumulative dose and delayed side effects). Studies have shown the safety and effectiveness of unilateral MRgFUS-thalamotomy in the treatment of ET. It has been successfully used in a few patients with Parkinson’s disease-related tremor, and in fewer patients with fragile X-associated tremor/ataxia syndrome. The safety and long-term effects of the procedure are still unclear, as temporary and permanent adverse events have been reported as well as recurrence of tremor.

Discussion

MRgFUS is a promising new surgical approach with a number of unknowns and unsolved issues. It represents a valuable option particularly for patients who refused or could not be candidates for other procedures, deep brain stimulation in particular.

Metastasis of an occult pulmonary carcinoma into meningioma: a case report

Tumour-to-tumour metastasis is an infrequent pathological phenomenon. Meningioma is the most common intracranial tumour where metastatic deposits may be found, the majority of which arise from breast and lung cancers. We describe an unusual case of occult pulmonary carcinoma metastasis into the intracranial meningioma. A 77-year old lady presented with acutely deteriorating hemiparesis. Her previous medical history was unremarkable. Radiological imaging revealed an expansive lesion, classified as meningioma, which was located parasagittally in the right premotor area. A well-capsulated tumour attached to the dura was removed surgically. The pathological examination demonstrated a mixture of angiomatous meningioma and pulmonary adenocarcinoma. Possible explanations for the development of a composite tumour and pathophysiology are described.

Lethal intratumoral haemorrhages of brain metastases during radiosurgery: case reports and literature review

Gamma Knife surgery (GKS) is an effective and important treatment modality in the management of brain metastases. The short-term complication rate is low and the tumour control rate high. Complications caused by acute radiation-induced oedema are rare and usually benign. In this article, two cases of lethal haemorrhagic event immediately following GKS are described from two centres, which had prompted us to review the literature.

Hydrogen is neuroprotective against surgically induced brain injury

Background

Neurosurgical operations cause unavoidable damage to healthy brain tissues. Direct surgical injury as well as surgically induced oxidative stress contributes to the subsequent formation of brain edema. Therefore, we tested the neuroprotective effects of hydrogen (H₂) in an established surgical brain injury (SBI) model in rats.

Materials and methods

Adult male Sprague - Dawley rats (weight 300-350g) were divided into three groups to serve as sham operated, SBI without treatment, and SBI treated with H₂ (2.9%). Brain water content, myeloperoxidase (MPO) assay, lipid peroxidation (LPO), and neurological function were measured at 24 hrs after SBI.

Results

SBI resulted in localized brain edema (p = < 0.001). Hydrogen (2.9%) administered concurrently with surgery significantly decreased the formation of cerebral edema (p = 0.028) and improved neurobehavioral score (p = 0.022). However, hydrogen treatment failed to reduce oxidative stress (LPO assay) or inflammation (MPO assay) in brain tissues.

Conclusions

Hydrogen appears to be promising as an effective, yet inexpensive way to reduce cerebral edema caused by surgical procedures. Hydrogen has the potential to improve clinical outcome, decrease hospital stay, and reduce overall cost to patients and the health care system.

Initial experience with the use of remote control monitoring and general anesthesia during radiosurgery for pediatric patients

The demand for general anesthesia in pediatric radiosurgery has been increasing, but the issues involved are not highlighted well in the medical literature. We developed remotely controlled monitoring and anesthesia techniques, and applied our system to three pediatric patients who underwent Gamma Knife radiosurgery with automated settings. Based on the perioperative safety management, the following issues are of considerable concern: to avoid emotional trauma associated with the treatment, to secure airway patency in a variety of head positions, and to apply all standard monitors. In this report, we describe the details of our project with a comprehensive literature review.

Stereotactic radiotherapy and radiosurgery in pediatric patients: analysis of indications and outcome

INTRODUCTION

We describe indications, outcomes, and risk profiles of fractionated stereotactic radiotherapy (SRT) and single fraction "radiosurgery" (SRS) in pediatric patients compared to the adult population and evaluate the causal role of SRS and SRT in inducing new neurological complications.

MATERIALS AND METHODS

Six children with AVMs and 12 children with neoplastic diseases were prospectively followed for >2 years after SRT/S. The survival, control of pathology, and specified neurological complications were analyzed. In tumor patients, the median overall survival time was 45 months (range 5-103) and the median progression free survival time was 35 months (range 5-98).

RESULTS

Control or regression of the tumor was obtained in 83% of patients with neoplastic disease. Three patients with malignant tumors died from disease progression. In AVMs the median time follow up was 52 months (range 27-100). All AVMs were obliterated. New neurological deficits occurred in 67%. SRT/S was considered the direct cause in 25%. All the neurological deficiencies related to SRT/S were focal and related to the irradiated areas. In tumor patients, midline lesions, malignant diagnosis, and additional treatment with surgery, chemotherapy, and craniospinal irradiation seemed to increase the risk of new deficits after SRT/S. In AVM patients, a high Spetzler-Martin grade seemed to carry a higher complication risk.

CONCLUSION

The risk of uncontrolled tumor disease or the risk of hemorrhage of non-obliterated AVM must be balanced against the overall risks and benefits of SRT/S. Following SRT/S, the risk of worsening pre-existing deficits is relatively high. The risk of inducing new long-term deficits is relatively low.

Long-term Outcomes of Stereotactic Radiosurgery for Arteriovenous Malformations in the Thalamus

BACKGROUND

Arteriovenous malformations (AVMs) in the thalamus carry a high risk of hemorrhage. Although stereotactic radiosurgery (SRS) is widely accepted because of the high surgical morbidity and mortality of these lesions, precise long-term outcomes are largely unknown.

OBJECTIVE

To review our experience with SRS for thalamic AVMs based on the latest follow-up data.

METHODS

Forty-eight patients with thalamic AVMs were treated by SRS using the Leksell Gamma Knife and were followed. Long-term outcomes including the obliteration rate, hemorrhage after treatment, and adverse effects were retrospectively analyzed.

RESULTS

The annual hemorrhage rate before SRS was 14%. The mean follow-up period after SRS was 66 months (range 6–198 months). The actuarial obliteration rate confirmed by angiography was 82% at 5 years after treatment, and the annual hemorrhage rate after SRS was 0.36%. Factors associated with higher obliteration rates were previous hemorrhage (P = .004) and treatment using new planning software (P = .001). Persistent worsening of neurological symptoms was observed in 17% and more frequently seen in patients who were treated using older planning software (P = .04) and a higher margin dose (P = .02). The morbidity rate for patients who received treatment planned using new software with a margin dose not more than 20 Gy was 12%.

CONCLUSION

SRS for thalamic AVMs achieved a high obliteration rate and effectively decreased the risk of hemorrhage, with less morbidity compared with other modalities. Longer follow-up to evaluate the risk of delayed complications and the effort to minimize the morbidity is necessary.