Gamma knife surgery of brain cavernous hemangiomas

Management of intracranial cavernous malformations using conservative vs. surgical and/or radiosurgical treatment: A systematic review and meta‑analysis

Intracranial cavernous malformations (CMs) are vascular lesions with a high bleeding rate. At present, the debate regarding their treatment is still ongoing. The present systematic review and meta-analysis aimed to evaluate the safety of surgery or radiosurgery (SRS) for the management of CMs and to determine their potential outcomes compared with conservative treatment. The present systematic review and meta-analysis investigated the relative articles involving the management of intracranial CMs, namely their natural history (conservative treatment) vs. surgical/SRS treatment through electronic databases until June, 2023. The collected variables included the first author's name, the study period covered, the year of publication, the total number of patients examined and their age, and the number of males. In total, six articles met the eligibility criteria. The total number of patients was 399 (157 in the surgery/SRS group and 242 in the conservative treatment group). The results revealed that surgical or SRS management is a safe procedure for CMs compared with conservative treatment. Notably, the use of hemosiderin in the pre-MRI, the free of seizures parameter and the neurological deficit parameters were associated with improved outcomes in the surgical or SRS group of patients.

Outcome of intracerebral cavernoma treated by Gamma Knife radiosurgery based on a double-blind assessment of treatment indication

BACKGROUND

The benefit and the risk profile of Gamma Knife radiosurgery (GKRS) for intracerebral cavernoma remains incompletely defined in part due to the natural history of low incidence of bleeding and spontaneous regression of this vascular malformation. In this study, we retrieved cases from a prospectively collected database to assess the outcome of intracerebral cavernoma treated with GKRS using a double blinded review process for treatment.

METHODS

From 2003 to 2018, there were 94 cases of cavernoma treated by GKRS in the doubly blinded assessments by two experienced neurological and approved for GKRS treatment. All the patients received GKRS with margin dose of 11-12 (Gray) Gy and afterwards were assessed for neurological outcome, radiologic response, and quality of life.

RESULTS

The median age of the patients was 48 (15-85) years with median follow up of 77 (26-180) months post SRS. The mean target volume was 1.93 ± 3.45 cc. In those who has pre-SRS epilepsy, 7 of 16 (43.7%) achieved seizure freedom (Engel I/II) and 9 of 16 (56.3%) achieved decreased seizures (Engel III) after SRS. Rebleeding occurred in 2 cases (2.1%) at 13 and 52 months post SRS. The radiologic assessment demonstrated 20 (21.3%) cases of decreased cavernoma volume, 69 (73.4%) were stable, and 5 (7.3%) increased size. Eighty-seven of 94 (92.5%) cases at the last follow up achieve improvement in their quality of life, but 7 cases (7.4%) showed a deterioration. In statistical analysis, the effective seizure control class (Engel I/II) was highly correlated with patient harboring a single lesion (p < 0.05) and deep seated location of the cavernoma (p < 0.01). New neurological deficits were highly correlated with decreased mental (p < 0.001) and physical (p < 0.05) components of quality of life testing, KPS (p < 0.001), deep seated location (p < 0.01), and increased nidus volume (p < 0.05). Quality of life deterioration either in physical component (p < 0.01), mental component (p < 0.01), and KPS (p < 0.05) was highly correlated with increased cavernoma volume.

CONCLUSION

Low margin dose GKRS for intracerebral cavernoma offers reasonable seizure control and improved quality of life while conferring a low risk of treatment complications including adverse radiation effect.

Gamma knife radiosurgery for brainstem cavernous malformations

OBJECTIVE

The goal of this retrospective study was to evaluate the efficacy and safety of gamma knife radiosurgery (GKS) for the treatment of brainstem cavernous malformations (CMs).

METHODS

Between January of 2009 and December of 2014, 43 patients (20 males and 23 females) with brainstem CMs were treated at the West China Hospital, Sichuan University, Gamma Knife Center. The mean age of these patients was 41.7 years. All of the patients experienced 1 or more episodes of symptomatic bleeding (range 1-4) before undergoing GKS. The mean volume of the malformations at the time of GKS was 442.1mm³, and the mean prescribed marginal radiation dose was 11.9Gy. The mean follow-up period after radiosurgery was 36 months (range 12-120 months).

RESULTS

Before GKS, 50 hemorrhages (1.2 per patient) were observed (25.0% annual hemorrhage rate). Three hemorrhages following GKS were observed within the first 2 years (3.92% annual hemorrhage rate), and 1 hemorrhage was observed in the period after the first 2 years (1.85% annual hemorrhage rate). In this study of 43 patients, new neurological deficits developed in only 1 patient (2.32%; permanent paresthesia on the left side of the face and the right lower limb of the patient). There were no deaths in this study.

CONCLUSION

GKS is a favorable alternative treatment for brainstem CMs. Using a low marginal dose treatment might reduce the rate of hemorrhage and radiation-induced complications.

Radiosurgery for symptomatic cavernous malformations: A multi-institutional retrospective study in Japan

BACKGROUND

A group study for symptomatic cavernous malformation (CM) treated with gamma knife (GK) surgery was performed.

METHODS

A total of 298 cases collected from 23 GK centers across Japan were included. Hemorrhage was the most common manifestation, followed by seizures and neurological deficits. Most of the lesions were located in the brainstem and basal ganglia, followed by the cerebral or cerebellar hemispheres. The CMs, which had a mean diameter of 14.8 mm, were treated using GK surgery with a mean marginal dose of 14.6 Gy.

RESULTS

In terms of hemorrhage-free survival (HFS), a marked dissociation was confirmed between the hemorrhage and seizure groups, while no obvious difference was noted between sexes. Superficial CMs located in cerebellum or lobar regions responded to the treatment better than deeply located CMs in the basal ganglia or brainstem. No significant difference of dose-dependent response was seen for three different ranges of marginal dose: Less than 15 Gy, between 15 and 20 Gy, and more than 20 Gy. Complications were more frequent after a marginal dose of over 15 Gy and in patients with lesions more than 15 mm in diameter. The rates of annual hemorrhage were estimated to be 7.4% during the first 2 years after radiosurgery and 2.8% thereafter. The overall hemorrhage rate after radiosurgery was 4.4%/year/patient.

CONCLUSION

The risk of hemorrhage is considerably reduced after GK treatment. The HFS as well as annual hemorrhage rate after GK treatment was apparently superior to that after conservative treatment for symptomatic CMs. To optimize the success of GK treatment, it is important to reduce the incidence of complications.

Stereotactic radiosurgery of intracranial cavernous malformations

Despite increasing worldwide experience, the role of stereotactic radiosurgery (SRS) in the management of cerebral cavernous malformations (CMs) remains controversial. Microsurgical excision of easily accessible CMs is typically safe; therefore, removal remains the gold standard for most of the symptomatic hemispheric lesions. However, there is now sufficient evidence supporting the use of SRS for the difficult cases. Waiting for the cumulative morbidity of the natural history to justify intervention does not serve the patient's interest, therefore, we argue for early radiosurgical intervention. Carefully designed randomized controlled trials might resolve controversies concerning the role of SRS in treating cerebral CMs.

Microsurgical or radiosurgical management of intracranial cavernomas

Cranial cavernous malformations (CCMs) constitute a heterogeneous group of lesions that tend to change dynamically over time with related periods of repeated exacerbation and alternating periods of remission. The decision on their management is based on estimating the inherent risk of further morbidity and the risk/benefit related to the particular treatment mode. Incidentally detected CCMs or lesions in asymptomatic patients presenting without major hemorrhage are best followed up. Complete resection of a CCM is the only healing option and is indicated for symptomatic or hemorrhagic lesions. In the large published series 83-92 % of the patients improved or remained unchanged after surgery, with only 8-11 % showing significant deterioration. For most patients, quality of life is improved. Analysis of the risk/benefit ratio for radiosurgery shows that it should not be regarded as an alternative option: It confers limited protection against bleeding and is related to a certain morbidity risk. In the subgroup of patients with symptomatic or hemorrhagic CCMs in locations that preclude surgical resection with acceptable risks, we recommend follow-up. The senior author is following a group of more than 80 such patients, and the vast majority remain free of hemorrhage and symptoms.

Gamma knife radiosurgery of brain cavernomas

PURPOSE

Radiosurgery of cavernomas should prevent rebleeding, growth of the lesion, and deterioration of clinical symptoms. However, there is no direct diagnostic tool to verify the endpoints of treatment. At present, the positive effects of radiosurgery are identified by clinical observation and analysis of imaging changes on magnetic resonance imaging during a sufficiently long follow-up period.

METHODS

Between 1992 and 2000, a total of 112 patients with brain cavernomas were treated with Gamma Knife radiosurgery at our center. In all, 59 patients experienced bleeding before radiosurgery; the remainder did not. The median age of patients was 42 years, the median volume of the cavernomas was 0.9 cm(3), and the median applied marginal dose was 16 Gy.

RESULTS

After a 2-year latent interval after treatment (median follow-up 84 months), the risk of bleeding in the group of patients with bleeding before radiosurgery had decreased from 3.7 % to 0.2 %. For the patients without bleeding before radiosurgery, the annual risk of bleeding was 0.8 %. The cavernoma size decreased in 53.0 % of cases and increased in 6.4 %. Epilepsy, if present before the treatment, was alleviated in 45 % of cases. The risks of temporary or permanent morbidity caused by radiosurgery were 14.6 % and 0.9 %, respectively.

CONCLUSION

Radiosurgery of cavernomas was associated with a low risk of permanent morbidity. The risk of rebleeding after the 2-year latent interval after radiosurgery had decreased. Treatment of cavernomas with no history of bleeding was halted at our center.

Surgical treatment of symptomatic cerebral cavernous malformations in eloquent brain regions

BACKGROUND

Despite the increased risk of hemorrhage and deteriorating neurological function of once-bled cerebral cavernous malformations (CM), the management of eloquently located CMs remains controversial.

METHODS

All eloquently located CMs (n = 45) surgically treated between 03/2006 and 04/2011 in our department were consecutively evaluated. Eloquence was characterized according to Spetzler and Martin's definition. The following locations were approached: brainstem, n = 16; sensorimotor, n = 8; visual pathway, n = 7; cerebellum (deep nuclei and peduncles), n = 7; basal ganglia, n = 4, and language, n = 3. Follow-up data was available for 41 patients (91 %) with a median interval of 14 months. Outcomes were evaluated according to the Glasgow outcome and the modified Rankin scale.

RESULTS

Immediately after surgery, 47 % (n = 21) had a new deficit. At follow-up, 80 % (n = 36) recovered to at least preoperative status or were better than before surgery, 9 % (n = 4) exhibited a slight, and 7 % (n = 3) had a moderate neurological impairment. Only two cases (4 %) with a new permanent severe deficit were observed, both related to dorsal brainstem surgery. The outcome after the surgery of otherwise located brainstem CMs was as beneficial as that for non-brainstem CMs. Patients with initially poor neurological performance fared worse than oligosymptomatic patients.

CONCLUSIONS

Despite the high postoperative transient morbidity, the majority improved profoundly during follow-ups. Compared with natural history, surgical treatment should be considered for all eloquent symptomatic CMs. Dorsal brainstem location and poor preoperative neurological status are associated with an increased postoperative morbidity.

Stereotactic LINAC radiosurgery for the treatment of brainstem cavernomas

BACKGROUND

The management of deep-seated cerebral cavernous malformations (CCMs) is still controversial. Although surgery remains the treatment of choice in patients with recurrent hemorrhage, patients with CCMs located in the brainstem are in many cases not eligible for resection due to high procedure-related morbidity and mortality. We evaluated the long-term outcome of LINAC radiosurgery (LINAC-RS) for the treatment of brainstem CCMs.

PATIENTS AND METHODS

Between December 1992 and March 2008, 14 patients (6 men, 8 women) harboring brainstem CCMs underwent LINAC-RS. Pretreatment neuroimaging showed no associated developmental venous angiomas (DVAs) in any of our patients. Prior to treatment, all patients suffered at least from one symptomatic hemorrhage (median 1.8, range 1–3). A median follow-up of 7.1 years (range 2.0–16.8 years) could be obtained in 12 patients. We applied a median tumor surface dose of 13.9 Gy (range 11–18 Gy; median tumor volume 1.6 ml, range 0.4–4.3 ml).

RESULTS

Following LINAC-RS, neurological outcome improved in 4 (33.3%) and remained unchanged in 8 patients (66.7%). Rebleeding with subsequent transient neurological status deterioration occurred in 4 patients (33.3%), leading to additional surgical resection in 2 patients (16.7%). The corresponding annual hemorrhage rate was 4.8% (4/82.8 patient–years). Adverse radiation effects (ARE, defined by perilesional hyperintensity on T2-weighted MR images) were revealed in 3 patients (25%), leading to transient neurological deficits in 2 patients (16.7%). There were no procedure-related complications leading to either permanent morbidity or mortality.

CONCLUSION

Our results support the role of LINAC-RS as an efficient and safe treatment to significantly reduce the annual hemorrhage rate in patients suffering from brainstem CCMs not eligible to microsurgery. Compared with radiosurgery for arteriovenous malformations (AVMs), the intervention-related morbidity is higher.

Comparison of serum zinc levels measured by inductively coupled plasma mass spectrometry in preschool children with febrile and afebrile seizures

Background

Changes in levels of trace elements have been proposed to underlie febrile seizures. Particularly, low zinc levels have been proposed as related factor of febrile seizure. In this study, we investigated whether mean serum zinc levels differed between children with febrile seizure and afebrile seizure.

Methods

Using inductively coupled plasma mass spectrometry, serum zinc levels were measured in 288 children who had been diagnosed with febrile seizures (N=248) and afebrile seizures (N=40). Mean serum zinc levels were compared between the 2 groups.

Results

Mean serum zinc level was 60.5±12.7 µg/dL in the febrile seizure group and 68.9 ±14.5 µg/dL in the afebrile seizure group. A significant difference in serum zinc levels was observed between the febrile and afebrile seizure groups (P<0.001).

Conclusions

Zinc levels in children with febrile seizure were significantly lower than those in children with afebrile seizure.

Stereotactic radiosurgery for deep-seated cavernous malformations: a move toward more active, early intervention. Clinical article

OBJECT

The role of radiosurgery in the treatment of cavernous malformations (CMs) remains controversial. It is frequently recommended only for inoperable lesions that have bled at least twice. Rehemorrhage can carry a substantial risk of morbidity, however. The authors reviewed their practice of treating deep-seated inoperable CMs to assess the complication rate of radiosurgery, the impact that radiosurgery might have on rebleeding, and whether a more active, earlier intervention is justified in managing this condition.

METHODS

The authors performed a retrospective analysis of 113 patients with 79 brainstem and 39 thalamic/basal ganglia CMs treated with Gamma Knife surgery. Lesions were stratified into 2 groups: those that might be lower risk with no more than 1 symptomatic bleed before radiosurgical treatment and those deemed high risk with multiple symptomatic hemorrhages before treatment.

RESULTS

Forty-one CMs had multiple symptomatic hemorrhages before radiosurgery with a first-ever bleed rate of 2.9% per lesion per year, a rebleed rate of 30.5% per lesion per year, and a median time of 1.5 years between the first and second bleeds. In this group the rebleed rate decreased to 15% for the first 2 years after radiosurgery and declined further to 2.4% thereafter. Pretreatment multiple bleeds led to persistent deficits in 72% of the patients. Seventy-seven CMs had no more than 1 symptomatic bleed before radiosurgery, making for a lifetime bleed rate of 2.2% per lesion per year. The short period between the presenting bleed and treatment (median 1 year) makes the natural history in this group uncertain. The rate of hemorrhage in the first 2 years after treatment was 5.1%, and 1.3% thereafter. Pretreatment hemorrhages resulted in permanent deficits in 43% of the patients in this group, a rate significantly lower than in the multiple-bleeds group (p < 0.001). Posttreatment hemorrhages led to persistent deficits in only 7.3% of the patients. Permanent adverse radiation effects were rare (7.3%) and minor in both groups.

CONCLUSIONS

Stereotactic radiosurgery is a safe management strategy for CMs in eloquent sites with the marked advantage of reducing rebleed risks in patients with repeated pretreatment hemorrhages. The benefit in treating CMs with a single bleed is less clear. Note, however, that repeated hemorrhage carries a significant risk of increased morbidity far in excess of any radiosurgery-related morbidity, and the authors assert that this finding justifies the early active management of deep-seated CMs.

Stereotactic radiosurgery for the treatment of symptomatic brainstem cavernous malformations

Object

The authors performed a retrospective review of prospectively collected data to evaluate the safety and efficacy of stereotactic radiosurgery (SRS) for the treatment of patients harboring symptomatic solitary cavernous malformations (CMs) of the brainstem that bleed repeatedly and are high risk for resection.

Methods

Between 1988 and 2005, 68 patients (34 males and 34 females) with solitary, symptomatic CMs of the brainstem underwent Gamma Knife surgery. The mean patient age was 41.2 years, and all patients had suffered at least 2 symptomatic hemorrhages (range 2–12 events) before radiosurgery. Prior to SRS, 15 patients (22.1%) had undergone attempted resection. The mean volume of the malformation treated was 1.19 ml, and the mean prescribed marginal radiation dose was 16 Gy.

Results

The mean follow-up period was 5.2 years (range 0.6–12.4 years). The pre-SRS annual hemorrhage rate was 32.38%, or 125 hemorrhages, excluding the first hemorrhage, over a total of 386 patient-years. Following SRS, 11 hemorrhages were observed within the first 2 years of follow-up (8.22% annual hemorrhage rate) and 3 hemorrhages were observed in the period after the first 2 years of follow-up (1.37% annual hemorrhage rate). A significant reduction (p < 0.0001) in the risk of brainstem CM hemorrhages was observed following radiosurgical treatment, as well as in latency period of 2 years after SRS (p < 0.0447). Eight patients (11.8%) experienced new neurological deficits as a result of adverse radiation effects following SRS.

Conclusions

The results of this study support a role for the use of SRS for symptomatic CMs of the brainstem, as it is relatively safe and appears to reduce rebleeding rates in this high-surgical-risk location.

Anterior transpetrosal and subtemporal transtentorial approaches for pontine cavernomas

OBJECTIVE

Pontine cavernomas are benign vascular lesions whose surgical treatment is challenging due to their localization. We report our experience in the surgical management of these lesions exclusively using a lateral, subtemporal transtentorial approach in high pontine lesions and an anterior petrosal approach in low pontine lesions.

METHODS

We performed a retrospective study on a series of patients who were operated on for a pontine cavernoma in our neurosurgery department between 1987 and 2007. In the study, we detail the patients' clinical and preoperative radiological data and compare the two surgical techniques we used. Finally, we analyze the postoperative follow-up, the morbidity encountered according to the surgical approach used, and the long-term outcomes.

RESULTS

We enrolled nine patients into the study. Six patients were operated on using an anterior petrosal approach. None of the patients died. Five patients were able to resume their former professional activity after surgery and were clearly improved following surgery. One patient was worse after surgery (hemiplegia and deafness). We used a subtemporal transtentorial approach in three of the patients. None of the patients died. Two of the patients were able to resume their prior professional activities without any sequels, and the third patient's condition worsened following surgery (temporal hematoma).

CONCLUSION

The lateral surgical approach for pontine cavernomas constitutes a reasonable surgical alternative to the transventricular, suboccipital, retromastoid, or transclival approaches. Patient morbidity in both approaches is acceptable, and the long-term outcome is satisfactory with respect to sequels and the resumption of prior professional activity.

Stereotactic radiosurgery for symptomatic solitary cerebral cavernous malformations considered high risk for resection

Object

A retrospective study was conducted to reassess the benefit and safety of stereotactic radiosurgery (SRS) in patients with solitary cerebral cavernous malformations (CCMs) that bleed repeatedly and are poor candidates for surgical removal.

Methods

Between 1988 and 2005 at the University of Pittsburgh, the authors performed SRS in 103 evaluable patients (57 males and 46 females) with solitary symptomatic CCMs. The mean patient age was 39.3 years. Ninety-eight percent of these patients had experienced 2 or more hemorrhages associated with new neurological deficits. Seventeen patients (16.5%) had undergone attempted resection before radiosurgery. Ninety-three CCMs were located in deep brain structures and 10 were in subcortical lobar areas of functional brain importance. The median malformation volume was 1.31 ml, and the median tumor margin dose was 16 Gy.

Results

The follow-up ranged from 2 to 20 years. The annual hemorrhage rate—that is, a new neurological deficit associated with imaging evidence of a new hemorrhage—before SRS was 32.5%. After SRS 22 hemorrhages were observed within 2 years (10.8% annual hemorrhage rate) and 4 hemorrhages were observed after 2 years (1.06% annual hemorrhage rate). The risk of hemorrhage from a CCM was significantly reduced after radiosurgery (p < 0.0001). Overall, new neurological deficits due to adverse radiation effects following SRS developed in 14 patients (13.5%), with most occurring early in our experience. Modifications in technique (treatment volume within the T2-weighted MR imaging–defined margin, use of MR imaging, and dose reduction for CCM in critical brainstem locations) further reduced risks after SRS.

Conclusions

Data in this study provide further evidence that SRS is a relatively safe procedure that reduces the rebleeding rate for CCMs located in high-surgical-risk areas of the brain.

Surgical treatment of brainstem cavernous malformations

BACKGROUND

The contemporary neurosurgeon is often confronted by cavernous malformations. Those located in the brainstem are particularly challenging

METHODS

This article reviews published series on the natural history and surgical outcomes of these lesions and discusses the surgical approaches used at our institution for their resection.

RESULTS

Despite their challenging location in the brainstem, appropriately selected lesions can be resected surgically with acceptable rates of morbidity and mortality.

CONCLUSIONS

Our institutional philosophy on the surgical treatment of brainstem cavernous malformations reflects the substantial surgical experience of the senior author.

Radiosurgery for angiographically occult vascular malformations

The use of radiosurgery for angiographically occult vascular malformations (AOVMs) is a controversial treatment option for those that are surgically inaccessible or located in eloquent brain. To determine the efficacy of this treatment, the authors reviewed the literature reporting hemorrhage rates, seizure control, and radiation-induced morbidity. They found overall hemorrhage rates of 2-6.4%, overall postradiosurgery hemorrhage rates of 1.6-8%, and stratified postradiosurgery hemorrhage rates of 7.3-22.4% in the period immediately to 2 years after treatment; these latter rates declined to 0.8-5.2% > 2 years after treatment. Of 291 patients presenting with seizure across 16 studies, 89 (31%) attained a seizure-free status and 102 (35%) had a reduction in seizure frequency after radiosurgery. Overall radiation-induced morbidity ranged from 2.5 to 59%, with higher complication rates in patients with brainstem lesion locations. Researchers applying mean radiation doses of 15-16.2 Gy to the tumor margin saw both low radiation-induced complication rates (0-9.1%) and adequate hemorrhage control (0.8-5.2% > 2 years after treatment), whereas mean doses >or= 16.5 Gy were associated with higher total radiation-induced morbidity rates (> 17%). Although the use of stereotactic radiosurgery remains controversial, patients with AOVMs located in surgically inaccessible areas of the brain may benefit from such treatment.

Does conservative management for brain stem cavernomas have better long-term outcome?

There has been a controversy in the last 15 years on the correct management of brain stem cavernomas. We have reviewed our experience of the last 10 years in a single Institution and reviewed related literature published in the last 15 years. We recorded the demographics, clinical presentation, rebleeding episodes, incidence of neurological events and outcome assessed by recording the change of the modified Rankin scale in 21 cases. Univariate analysis was applied to test the effect of demographics, and presentation on the incidence and timing of rebleeding, chance of having a new neurological event, the number of subsequent neurological events and outcomes. Six cases were treated with surgery and 15 cases were managed conservatively. We obtained follow-up data in 20 patients (95%). Mean follow-up period was 79.7 months (range: 6-244, median 70 months). There were 0.05 rebleeding events per patient-year and 0.1 episodes of neurological deterioration per patient-year. No mortality was noted in either the surgical or the non-surgical group. Three of the six surgical cases had a reoperation. The outcome was improved in one patient, unchanged in 1, and worse in 3 surgical patients. In the case of conservative management the outcome was improved in two patients, unchanged in five patients, and worse in eight patients. Outcome was worse in the case of multiple cavernomas (p = 0.012). Our findings suggest that conservative management may be appropriate in individual cases when compared with surgery, but this difference was not statistically significant enough in order to support a change in practice. The natural history of brain stem cavernomas appears more benign than previously thought.

Adverse radiation effects after Gamma Knife Surgery in relation to dose and volume

INTRODUCTION

The relationship between target volume and adverse radiation effects (AREs) at low prescription doses requires elucidation. The development of AREs in three series of patients treated in the Gamma Knife is analysed in relation to prescription dose and target volume.

MATERIALS AND METHODS

There were three groups. In group 1, there were of 275 patients with meningiomas; in group 2, 132 patients with vestibular schwannomas; and in group 3, 107 patients with arteriovenous malformations (AVMs). The minimum follow-up for each group was more than 24 months. All patients were followed up at six monthly intervals. The patients with tumours received a prescription dose of 12 Gy, which was varied to protect normal structures but not in relation to tumour volume per se. The desired AVM prescription dose was 25 Gy, but this was also reduced to protect normal structures and to keep the total dose within certain pre-defined limits. All AREs refer to intra-parenchymal increased perilesional T2 signal on MR irrespective of clinical correlation.

RESULTS

There was no relationship between tumour volume and the development of ARE in the tumour groups. There was a highly significant relationship between target volume and the development of ARE for the AVMs with their much higher dose. Radiation-induced clinical trigeminal and facial nerve deficits with both vestibular schwannomas and meningiomas were always associated with an increased T2 signal in the neighbouring brainstem parenchyma.

CONCLUSIONS

The relationship between target volume and the risk of adverse radiation effects may not apply with lower prescription doses. Individual radiosensitivity may explain why a minority suffer AREs unrelated to target volume. It is possible that radiation-induced brainstem parenchymal damage with concomitant cranial nerve deficits may be commoner after radiosurgery than is usually thought. If tumour control with lower doses is adequate, radiosurgery could be safely considered for larger targets associated with a high risk from microsurgery.

Cavernous angioma of the vestibular nerve: case report and literature review

BACKGROUND

To date, 50 cases of cavernous angioma in the CPA have been reported, and previous reports did not describe the tumor's site of origin. We describe a case of a small, extraaxial cavernous angioma of the vestibular nerve. We also propose a reclassification system for cavernous angioma of the CPA based on the tumor's site of origin.

CASE DESCRIPTION

A 39-year-old female patient had recurrent deteriorating vertigo and a right hearing disturbance. Magnetic resonance imaging revealed a cavernous angioma of the right CPA. Surgery was performed through a right lateral suboccipital approach. In the present case, the mass was attached to and covered the cisternal portion of the vestibular nerve, and it contained microvessels that were fed from the vascular plexus of the vestibular nerve. The tumor was resected en bloc, and the microvessels feeding it were cauterized.

CONCLUSIONS

On the basis of our review of 50 cases of cavernous angioma of the CPA, we propose that these tumors can be classified according to whether they develop from the venous plexus of the dura matter or of a cranial nerve. We also suggest that the site of origin affects the postoperative symptoms.

[Role of radiosurgery in the management of intracranial cavernomas. Review of the literature]

From a review of the literature dealing with radiosurgery of cavernous malformations, we have analyzed its impact on hemorrhagic risk, epilepsy, histological modifications, morbidity and potential indications of treatment. Radiosurgery could significantly reduce the hemorrhagic risk, in a selected population with a high risk of hemorrhage, after an interval of about 2 years, but cannot provide protection against rebleeding. As for epilepsy related to the lesion, a significant reduction of seizures has been observed in certain cases, with better control in case of recent evolution and simple seizures linked to the site of the vascular malformation. Histologic lesions are vascular fibrosis, fibrinoid necrosis and ferrugination, without good correlation with results of CT scan or MRI. Morbidity of radiosurgery seems higher compared to other diseases with similar doses and target volumes. The rate of transient complications was about 25%, with permanent sequelae in 5 to 10% of patients. This would be due to a radiosensitizing effect of the hemosiderin halo around the lesion. Radiosurgery can be proposed for non-surgical lesions with a high risk of hemorrhage, nevertheless the superiority of the technique over conservative treatment has to be proven. Without long-term prospective studies, the efficiency of RS for cavernomas remains questionable and subject to debate. New imaging methods proving the obstruction of the cavernous malformation are needed.

Surgical treatment of symptomatic cavernous malformations of the brainstem

INTRODUCTION AND OBJECTIVES

Cavernous malformations (CM) at the level of the brainstem, continue to present a challenge in therapeutic terms and are an important source of controversy. Here we present our experience and the results obtained by adopting surgical treatment.

MATERIALS AND METHODS

The results of a consecutive series of 17 patients were studied. The surgical intervention was designed after: 1. A neurological examination. 2. MRI and cerebral angiography. 3. Correlation with anatomical brainstem maps. The surgical intervention was approached from the most damaged zone or through a zone which was functionally least important.

RESULTS

Complete extirpation was achieved in 15 patients without mortality. In a few patients the surgical intervention temporarily aggravated the prior lesion of the cranial nerves (2/17) or damage new sensory tracts (2/17). The functional post-operative recovery was good, in terms of consciousness (4/5), cranial nerves (11/17), the pyramidal tract (3/5) and the cerebellum (2/4). Of the patients that were operated, 14 of 17 returned to their professional activities.

CONCLUSIONS

The results of surgery can surpass the morbidity-mortality of the natural history or treatment with radiosurgery. There is a clear consensus in recommending surgical intervention for CMs that are superficially located, in young patients and in those with a risk of further bleeding. It is probably best that the surgery is performed during the subacute period, when the MRI offers a clear image confirming the presence of the CM.

Neurovascular radiosurgery

SUMMARY

This article focuses on the treatment of neurovascular diseases, in particular brain arteriovenous malformations (BAVMs), with radiosurgery. The target group for this review is physicians who manage patients with neurovascular diseases, but are not actively engaged in radiosurgery. Radiosurgery for BAVMs is an established treatment with clearly defined risks and benefits. The efficacy of radiosurgery for dural arteriovenous shunts (DAVSs) is probably similar but the treatment has not yet gained the same acceptance. Radiosurgical treatment of cavernomas (cavernous hemangiomas) remains controversial. Well founded predictive models for BAVM radiosurgery show: * The probability of obliteration depends on the dose of radiation given to the periphery of the BAVM. * The risk of adverse radiation effects depends on the total dose of radiation, i.e. the amount of energy imparted into the tissue. The risk is greater in centrally located lesions. The risk of damage to brainstem nucleii and cranial nerves must be added to the risk predicted from current outcome models. * The risk of hemorrhage during the time span before obliteration depends on the BAVM volume, the dose of radiation to the periphery of the lesion and the age of the patient. Central location is a probably also a risk factor.

LINAC radiosurgery for intracranial cavernous malformation: 10-year experience

BACKGROUND

The annual hemorrhage rate of intracranial cavernous malformation (CM) is reported to range from 0.23% to 1.1%. Because of the low hemorrhage rate, operating on a deep symptomatic lesion with or without hemorrhage is considered controversial. For the prevention of hemorrhage, radiosurgery is an alternative method, targeting smaller lesions and delivering higher doses of radiation. Linear accelerator (LINAC) radiosurgery, aside from the gamma knife (GK), is not often discussed in the treatment of CM.

PATIENTS AND METHODS

From 1995 to 2005, 30 patients presenting with hemorrhage or seizures, aged 14-79 years (mean 24.0 years) with single (27 patients) or multiple (three patients) CMs received LINAC radiosurgery at our institute. Six patients received LINAC radiosurgery following craniotomy for residual lesions revealed by the follow-up MRI. The temporal lobe was the most common site for CM in this series (n=8), followed by the brain stem (n=7). Thirty patients received 34 radiosurgery treatments with peripheral doses ranging from 800 cGy to 2200 cGy. The mean follow-up time was 59.9 months (range 1-122 months).

RESULTS

One patient re-bled post-radiosurgery (0.67% in 149.75 observation-years). Two patients had asymptomatic post-LINAC edema (6.7%). Those three patients were symptom-free during the follow-up period.

CONCLUSION

We suggest that LINAC radiosurgery is a relatively safe technique for treating deep or residual CM, although the actual effectiveness for CM obliteration is not known.