La radiochirurgie dans le traitement des cavernomes. Expérience de 17 lésions traitées chez 15 patients

Cavernomas: Outcomes after gamma-knife radiosurgery in Iran

Background:

Treatment of cavernomas remains a challenge in surgically inaccessible regions. The purpose of this study was to evaluate outcomes after gamma-knife surgery (GKS) for these patients.

Materials and Methods:

A retrospective review of 100 patients treated between 2003 and 2011 was conducted in order to evaluate hemorrhage rates, complications, radiation effects after GKS. Dosage at the tumor margin was stratified into two groups: those that received ≤13 Gy; and those who received >13 Gy. The demographic and clinical characteristics of patients including age, gender, and hemorrhage rates were extracted from care records.

Results:

The median age was 32.5 years (ranging from 15 to 79). 44% were female. The median follow-up time was 42.2 months (ranging from 24 to 90). The median volume of the lesions was 1050.0 mm³ (ranging from 112.0 to 4100.0) before GKS. A reduction of 27.5% in median size of cavernomas was achieved at the last follow-up. There was 12% treatment-related morbidity after GKS. The hemorrhage rate in the first 2 years after GKS was 4.1% and 1.9% thereafter. There was no mortality due to GKS, and 93 patients were alive at the last follow-up. The radiation-related complication developed with marginal dose 13 Gy.

Conclusion:

The GKS for cavernomas appears to be a safe and beneficial in carefully selected patients. Low-dose GKS may be effective for the management of cavernous malformations.

Symptomatic cavernous malformations of the brainstem: functional outcome after microsurgical resection

Brainstem cavernous malformations are associated with a considerable risk of hemorrhage and subsequent morbidity. This study provides a detailed work-up of clinical and radiological outcome as well as identification of prognostic factors in patients who had suffered from symptomatic hemorrhages. Patients who had undergone surgery of symptomatic BSCMs were evaluated pre- and postoperatively both neurologically and neuroradiologically supplemented by telephone interviews. Additionally, patients were scored according to the Scandinavian Stroke Scale. Multiple uni- and multivariate analyses of possible clinical and radiological prognostic factors were conducted. The study population comprised 35 patients. Mean age at operation was 39.3 ± 13.0 years with microsurgical resection of a total of 37 different BSCMs between 2002 and 2011. Median clinical follow-up was 44.0 months (range 8-116 months). Postoperative MRI showed eventually complete resection of all BSCMs. Postoperative overall outcome revealed complete resolution of neurological symptoms for 5/35 patients, 14/35 improved and 9/35 remained unchanged. 7/35 suffered from a postoperative new and permanent neurological deficit, mostly affecting the facial nerve or hemipareses with mild impairment. Pre- and postoperative Scandinavian Stroke Scale scores were 11.0 ± 2.4 and 11.4 ± 2.2 (p = 0.55). None of the analyzed factors were found to significantly correlate with patients' clinical outcome. Complete resection of brainstem cavernous malformations can be achieved with an acceptable risk for long-term morbidity and surgery-related new deficits (~20 %). Neurological outcome is mainly determined within the first 6 months after surgery. Surgical treatment of brainstem cavernous malformations is recommended in symptomatic patients, in whom the lesion is accessible for surgery.

Surgical management of brainstem cavernous malformations

Bleeding from brainstem cavernomas may cause severe deficits due to the absence of non-eloquent nervous tissue and the presence of several ascending and descending white matter tracts and nerve nuclei. Surgical removal of these lesions presents a challenge to the most surgeons. The authors present their experience with the surgical treatment of 43 patients with brainstem cavernomas. Important aspects of microsurgical anatomy are reviewed. The surgical management, with special focus on new intraoperative technologies as well as controversies on indications and timing of surgery are presented. According to several published studies the outcome of brainstem cavernomas treated conservatively is poor. In our experience, surgical resection remains the treatment of choice if there was previous hemorrhage and the lesion reaches the surface of brainstem. These procedures should be performed by experienced neurosurgeons in referral centers employing all the currently available technology.

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.

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.

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.

CAVERNOUS MALFORMATIONS OF THE BASAL GANGLIA AND THALAMUS

CAVERNOUS MALFORMATIONS OF the basal ganglia and thalamus present a unique therapeutic challenge to the neurosurgeon given their unclear natural history, the risk of surgical treatment, and the unproven efficacy of radiosurgical therapy. Via a PubMed search of the English and French literature, we have systematically reviewed the natural history and surgical and radiosurgical management of these lesions reported through April 2008. Including rates cited for “deep” cavernous malformations, annual bleeding rates for these lesions varied from 2.8% to 4.1% in the natural history studies. Across surgical series providing postoperative or long-term outcome data on 103 patients, we found an 89% resection rate, a 10% risk of long-term surgical morbidity, and a 1.9% risk of surgical mortality. The decrease in hemorrhage risk reported 2 years after radiosurgery might be a result of natural hemorrhage clustering, underscoring the unproven efficacy of this therapeutic modality. Given the compounded risks of radiation-induced injury and post-radiosurgical rebleeding, radiosurgery at modest dosimetry (12–14 Gy marginal doses) is only an option for patients with surgically inaccessible, aggressive lesions.

SYMPTOMATIC BRAINSTEM CAVERNOMAS

OBJECTIVE

The goal of this study was to analyze the natural history of symptomatic brainstem cavernomas (medulla, pons, or midbrain) and outcome after surgical resection.

METHODS

We retrospectively analyzed clinical data of all patients who presented to our institution with symptomatic brainstem cavernomas between 1995 and 2007 (n = 44).

RESULTS

After a first neurological event, the median event-free interval was 2 years, with an annual event rate of 42%. After a second neurological event (new neurological deficit or significant worsening of the previous deficit), the median event-free interval was only 5 months, with a monthly event rate of 8%. After an observation period of up to 8 years, all patients ultimately underwent surgery. In 95% of the patients, surgery successfully prevented further events during a median follow-up period of 11 months (1 month–7 years; P &lt; 0.001). The postoperative event rate was 5% per year in the first 2 years and 0% thereafter. In the multivariate analysis, only the preoperative modified Rankin scale score was predictive of the surgical outcome (odds ratio, 36.7; P = 0.015). The conditions of 2 patients (5%) were clinically worse compared with their preoperative conditions during the 1-year follow-up period; in one of these patients, this was caused by recurrent events. There was no mortality.

CONCLUSION

The event rate of symptomatic lesions seems to be high, particularly after recurrent events. Surgical morbidity can be low. Timely and complete surgical resection is recommended for symptomatic brainstem cavernomas to prevent patients' functional decline owing to recurrent events.