Cavernous malformations of the brainstem: experience with 100 patients

Cavernous malformations of the brainstem presenting in childhood: surgical experience in 40 patients

BACKGROUND

Brainstem cavernous malformations (BSCMs) are believed to compose 9% to 35% of all cerebral cavernous malformations, but these lesions have been reported in children in very limited numbers.

OBJECTIVE

To review surgical outcomes of pediatric patients with BSCMs treated at 1 institution.

METHODS

We retrospectively analyzed the course of 40 pediatric patients (19 males, 21 females; age range, 10 months to 18.9 years; mean, 12.3 years) who underwent surgery between 1984 and 2009. Age, sex, presenting symptoms, location of lesion, surgical approach, new postoperative deficits, Glasgow Outcome Scale score, recurrences, and resolution of baseline symptoms were recorded.

RESULTS

Thirty-nine patients experienced hemorrhage before surgery. Lesion locations included the pons (n=22), midbrain (n=4), midbrain and thalamus (n=4), pontomesencephalic junction (n=3), medulla (n=3), pontomedullary junction (n=3), and cervicomedullary junction (n=1). Mean lesion size was 2.3 cm. Mean length of hospital stay was 10.7 days. The average clinical follow-up was 31.9 months in 36 patients with follow-up after discharge. At last follow-up, 5 patients had experienced symptoms and/or imaging consistent with rehemorrhage, either from a residual that enlarged or true recurrence (5.25% annual rebleed risk per patient after surgery); 2 required reoperation for further resection of cavernoma. Mean Glasgow Outcome Scale score was 4.2 on admission, 4.05 at discharge, and 4.5 at latest follow-up. Preoperative symptoms and deficits improved in 16 patients (40%). New neurological deficits developed in 19 patients (48%) and resolved in 9, leaving 10 patients (25%) with new permanent deficit.

CONCLUSION

Compared with adults, pediatric patients with BCSMs tend to have larger lesions and higher rates of recurrence (regrowth of residual lesion). Given the greater life expectancy of children, surgical treatment seems warranted in those with surgically accessible lesions that have bled. Outcomes were similar to those in our adult series of patients with BSCMs.

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.

Advances in the Treatment and Outcome of Brainstem Cavernous Malformation Surgery

BACKGROUND:

Brainstem cavernous malformations (BSCMs) are relatively uncommon, low-flow vascular lesions. Because of their relative rarity, relatively little data on their natural history and on the efficacy and durability of their treatment.

OBJECTIVE:

To evaluate the long-term durability of surgical treatment of BSCMs and to document patient outcomes and clinical complications.

METHODS:

The charts of all patients undergoing surgical treatment of BSCM between 1985 and 2009 were reviewed retrospectively. The study population consisted of 300 patients who had surgery for BSCM. Forty patients were under 19 years of age at surgery; pediatric BSCMs have been reported separately. Patient demographics, lesion characteristics, surgical approaches, and patient outcomes were examined.

RESULTS:

The study population consisted of 260 adult patients with a female-to-male ratio of 1.5 and mean age of 41.8 years. Of the 260 patients, 252 presented with a clinical or radiographic history of hemorrhage. The mean follow-up in 240 patients was 51 months. The mean Glasgow Outcome Scale on admission, at discharge, and at last follow-up was 4.4, 4.2, and 4.6. Postoperatively, 137 patients (53%) developed new or worsening neurological symptoms. Permanent new deficits remained in 93 patients 3(36%). There were perioperative complications in 74 patients (28%); tracheostomy, feeding tube placement, and cerebrospinal fluid leakage were most common. Eighteen patients (6.9%) experienced 20 rehemorrhages. Twelve patients required reoperation for residual/recurrent BSCM. The overall annual risk of postoperative rehemorrhage was 2%/patient.

CONCLUSION:

Although BSCM surgery has significant associated risks, including perioperative complications, new neurological deficits, and death, most patients have favorable outcomes. Overall, surgery markedly improved the risk of rehemorrhage and related symptoms and should be considered in patients with accessible lesions.

Spontaneous bleeding into a suprasellar cavernous angioma of a neonate: case report and literature review

INTRODUCTION

Cavernous angiomas (CA) are congenital intraparenchymal vascular malformations that contain sinusoidal spaces lined by a single-layer endothelium, separated by collagenous stroma with no intervening brain parenchyma. Despite the congenital origin of CA, they rarely present in the neonatal and prenatal period. In this paper, we present a case report of a neonatal suprasellar CA that presented with a bleed. We also present a literature review focusing on specific features of intracranial CA in the neonatal and fetal age groups.

CASE REPORT

A 27-day-old neonate presented with a left eye ptosis for 2 days, followed by a generalized seizure. A head computed tomography revealed a suprasellar hematoma with intraventricular and subarachnoid extension. Brain magnetic resonance imaging revealed hemorrhages of various ages. Magnetic resonance angiography did not reveal any vascular malformation. Surgical exploration of the suprasellar mass revealed a capsulated dense hematoma. Postoperatively, the neonate was weaned of artificial ventilation over a protracted period and remained hemiparetic with signs of third nerve palsy. Pathology revealed a CA. CA presenting as a suprasellar bleed with subarachnoid and intraventricular extension is very rare especially among neonates. To the best of our knowledge, 20 cases of CA have been reported in the neonatal and fetal period in the English literature. Neonatal CA in general and suprasellar location in particular are extremely rare lesions. Neonatal/fetal CA seems to present more aggressively and have a worse prognosis compared to those presenting at a later age.

Cavernous malformations

Cavernous malformations (CMs) are vascular lesions found in the central nervous system (CNS) and throughout the body and have been called cavernomas, cavernous angiomas, and cavernous hemangiomas. This article discusses the epidemiology, natural history, diagnosis, treatment and follow-up of children who are found to harbor these lesions. CMs affect children by causing hemorrhage, seizure, focal neurologic deficits, and headache. Diagnosis is best made with magnetic resonance imaging. Patients with multiple lesions should be referred for genetic evaluation and counseling. Individuals with symptomatic, growing, or hemorrhagic malformations should be considered for surgical resection. Close follow-up after diagnosis and treatment is helpful to identify lesion progression or recurrence.

Modern management of brainstem cavernous malformations

Over the last 2 decades, there have been dramatic advancements in our understanding of and the ability to treat brainstem cavernous malformations (BCMs). Once thought untreatable, BCMs are now being more aggressively and safely treated microsurgically as a result of advances in monitoring and imaging technologies, as well as refinement of surgical techniques. BCMs deemed inoperable are being treated with radiosurgery, and experience with dosing and targeting has improved the safety of this treatment modality as well. Much work remains to be done, and prospective randomized trials would undoubtedly further existing knowledge.

Retrosigmoid suprafloccular transhorizontal fissure approach for resection of brainstem cavernous malformation

OBJECTIVE

This study examined the usefulness of a surgical approach (retrosigmoid suprafloccular transhorizontal fissure approach) for resection of brainstem cavernous malformations (CMs).

METHODS

An anatomic study concerning the retrosigmoid suprafloccular transhorizontal fissure approach was performed with 3 cadaveric heads. Clinical course was retrospectively reviewed for 10 patients who underwent microsurgical resection of brainstem CMs with this approach. Medical, surgical, and neuroimaging records of these patients were evaluated.

RESULTS

In the anatomic study, after standard suboccipital retrosigmoid craniotomy, the horizontal fissure on the petrosal surface of the cerebellum was dissected between the superior semilunar lobule and flocculus. With this approach, the root entry zone of the trigeminal nerve and the middle cerebellar peduncle could be exposed by superior retraction of the superior semilunar lobule. The lateral surface of the pons was then easily visible around the root entry zone. When this approach was used for 10 brainstem CMs, complete resection was achieved in 9 patients (90%). No mortality was encountered in this study. New neurological deficits occurred in the early postoperative period for 4 patients but were transient in 3 patients. Neurological status at final follow-up was improved in 4 patients (40%), unchanged in 5 patients (50%), and worse in 1 patient (10%) compared with preoperative conditions.

CONCLUSION

The retrosigmoid suprafloccular transhorizontal fissure approach is useful for the resection of lateral pontine CMs.

Update on the natural history of cavernous malformations and factors predicting aggressive clinical presentation

Cavernous malformations (CMs) are angiographically occult, low-pressure neurovascular lesions with distinct imaging and clinical characteristics. They present with seizure, neurological compromise due to lesion hemorrhage or expansion, or as incidental findings on neuroimaging studies. Treatment options include conservative therapy, medical management of seizures, surgical intervention for lesion resection, and in select cases stereotactic radiosurgery. Optimal management requires a thorough understanding of the natural history of CMs including consideration of issues such as mode of presentation, lesion location, and genetics that may impact the associated neurological risk. Over the past 2 decades, multiple studies have been published, shedding valuable light on the clinical characteristics and natural history of these malformations. The purpose of this review is to provide the reader with a concise consolidation of this published material such that they may better understand the risks associated with CMs and their implications on patient treatment.

Surgical approaches to brainstem cavernous malformations

Brainstem cavernous malformations (CMs) are low-flow vascular lesions in eloquent locations. Their presentation is often marked with symptomatic hemorrhages that appear to occur more frequently than hemorrhage from supratentorial cavernomas. Brainstem CMs can be removed using 1 of the 5 standard skull-base approaches: retrosigmoid, suboccipital (with or without telovelar approach), supracerebellar infratentorial, orbitozygomatic, and far lateral. Patients being referred to a tertiary institution often have lesions that are aggressive with respect to bleeding rates. Nonetheless, the indications for surgery, in the authors' opinion, are the same for all lesions: those that are symptomatic, those that cause mass effect, or those that abut a pial surface. Patients often have relapsing and remitting courses of symptoms, with each hemorrhage causing a progressive and stepwise decline. Many patients experience new postoperative deficits, most of which are transient and resolve fully. Despite the risks associated with operating in this highly eloquent tissue, most patients have had favorable outcomes in the authors' experience. Surgical treatment of brainstem CMs protects patients from the potentially devastating effects of rehemorrhage, and the authors believe that the benefits of intervention outweigh the risks in patients with the appropriate indications.

Operative management of brainstem cavernous malformations

Brainstem cavernous malformations (CMs) are complex lesions associated with hemorrhage and neurological deficit. In this review, the authors describe the anatomical nuances relating to the operative techniques for these challenging lesions. The resection of brainstem CMs in properly selected patients has been demonstrated to reduce the risk of rehemorrhage and can be achieved relatively safely in experienced hands.

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.

The presigmoid approach to anterolateral pontine cavernomas. Clinical article

OBJECT

Anterolateral cavernomas of the pons have been surgically removed via a variety of approaches, commonly retrosigmoid or transventricular. The goal in this study was to evaluate the presigmoid approach as an alternative.

METHODS

Clinical data were reviewed in 9 patients presenting with anterolateral pontine cavernomas between 1999 and 2007.

RESULTS

All patients were treated via a presigmoid approach, which provided a nearly perpendicular trajectory to the anterolateral pons. The brainstem was entered through a "safe zone" between the trigeminal nerve and the facial/vestibulocochlear nerve complex. Complete resection was achieved in all cases. No patient experienced recurrent events during follow-up (1-24 months). The patients' modified Rankin Scale score improved within 1 year of surgery (1.7 ± 0.4) compared with baseline (2.6 ± 0.2; p < 0.05). Only one patient experienced a new deficit (decreased hearing), which was corrected with a hearing aid.

CONCLUSIONS

The presigmoid approach is recommended for the resection of anterolateral pontine cavernomas. With this approach, the need for cerebellar retraction is nearly eliminated. The lateral "presigmoid" entry point creates a trajectory that allows complete resection of even deep lesions at this level, or anterior to the internal acoustic meatus.

Cavernous malformations

Cavernous malformations (CMs) are a subset of neurovascular malformations, which include arteriovenous malformations (AVMs), venous malformations, and capillary telangiectasias. CMs are referred to by many names, which may contribute to their being mistaken for malignant entities such as angiomas or hemangiomas. They are not, however, neoplastic; they are true vascular malformations with their own natural history and treatment. This article describes CMs and their clinical manifestations, methods of diagnosis, and types of treatment. CMs exist in both sporadic and familial forms. Nurses caring for patients with CMs should be aware of the specific characteristics of CMs that differentiate them from other neurovascular lesions.

Advances in the biology of cerebral cavernous malformations

OBJECT

To provide a review of current, high-impact scientific findings pertaining to the biology of cerebral cavernous malformations (CCMs).

METHODS

A comprehensive literature review was conducted using PubMed to examine the current literature regarding the molecular biology and pathophysiology of CCMs.

RESULTS

In this literature review, a comprehensive approach is taken to review the current scientific status of CCMs. This includes discussion of molecular biology and animal models, ultrastructure and angioarchitectural features and immunological methods and hypotheses.

CONCLUSIONS

Studies examining the molecular biology of CCMs have shown that genes involved in angiogenesis, blood-brain barrier formation, cell size regulation, vascular permeability and apoptosis play critical roles in the ontogeny of this disease. In vivo work suggests the likelihood of a "two-hit mechanism" resulting in somatic mosaicism and biallelic loss of angiogenic genes. The etiological effects of angioarchitecture and immune response within these lesions further complicate the pathophysiology. Future treatment endeavors will necessitate exploitation of the multiple facets of CCM formation to maximize success at CCM prevention or obliteration.

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.

Cavernous malformations of the optic pathway and hypothalamus: analysis of 65 cases in the literature

Object

Cavernous malformations (CMs) of the optic pathway and hypothalamus (OPH) are extremely rare. Patients with these lesions typically present with chiasmal apoplexy, characterized by sudden visual loss, acute headaches, retroorbital pain, and nausea. Surgical removal is the recommended treatment to restore or preserve vision and to eliminate the risk of future hemorrhage. However, the anatomical location and eloquence of nearby neural structures can make these lesions difficult to access and remove. In this study, the authors review the literature for reported cases of OPH CMs to analyze clinical and radiographic presentations as well as surgical approaches and neurological outcomes.

Methods

A MEDLINE/PubMed search was performed, revealing 64 cases of OPH CMs. The authors report an additional case in the study, making a total of 65 cases. Each case was analyzed for clinical presentation, lesion location, radiographic features, treatment method, and visual outcome.

Results

In 65 patients with OPH CMs, the optic chiasm was affected in 54 cases, the optic nerve(s) in 35, the optic tract in 13, and the hypothalamus in 5. Loss of visual field and acuity was the most common presenting symptom (98%), followed by headache (60%). The onset of symptoms was acute in 58% of patients, subacute in 15%, and chronic progressive in 26%. Computed tomography scans revealed hyperdense suprasellar lesions, with calcification visible in 56% of cases. Magnetic resonance imaging typically demonstrated a heterogeneous lesion with mixed signal intensities suggestive of blood of different ages. The lesion was often surrounded by a peripheral rim of hypointensity on T2-weighted images in 60% of cases. Minimal or no enhancement occurred after the administration of gadolinium. Hemorrhage was reported in 82% of cases. Most patients were surgically treated (97%) using gross-total resection (60%), subtotal resection (6%), biopsy procedure alone (6%), biopsy procedure with decompression (23%), and biopsy procedure followed by radiation (2%). Those patients who underwent gross-total resection had the highest rate of visual improvement (85%). Two patients were treated conservatively, resulting in complete blindness in 1 patient and spontaneous recovery of vision in the other patient.

Conclusions

Cavernous malformations of the OPH are rare and challenging lesions. Gross-total resection of these lesions is associated with favorable visual outcomes. Emergent surgery is warranted in patients presenting with chiasmal apoplexy to prevent permanent damage to the visual pathway.

Brainstem cavernous malformations: anatomical, clinical, and surgical considerations

Symptomatic brainstem cavernous malformations carry a high risk of permanent neurological deficit related to recurrent hemorrhage, which justifies aggressive management. Detailed knowledge of the microscopic and surface anatomy is important for understanding the clinical presentation, predicting possible surgical complications, and formulating an adequate surgical plan. In this article the authors review and illustrate the surgical and microscopic anatomy of the brainstem, provide anatomoclinical correlations, and illustrate a few clinical cases of cavernous malformations in the most common brainstem areas.

Brainstem cavernous malformations: a review with two case reports

Central nervous system (CNS) cavernous malformations (CMs) are developmental malformations of the vascular bed with a highly variable clinical course due to their dynamic nature. We present one case of 'de novo' brainstem cavernous malformation after radiation therapy adding to the increasing number of reported cases in the medical literature, and the case of a pregnant patient with symptomatic intracranial hemorrhage related to brainstem CMs to illustrate the complex nature in management of these patients, followed by a review of clinical and radiographic characteristics. CMs account for 8-15% of all intracranial and intraspinal vascular malformations. Although traditionally thought to be congenital in origin, CMs may present as acquired lesions particularly after intracranial radiation therapy. Clinical manifestations are protean and surgical treatment should be considered for patients with progressive neurologic deficits.

Susceptibility weighted magnetic resonance imaging of cerebral cavernous malformations: prospects, drawbacks, and first experience at ultra–high field strength (7-Tesla) magnetic resonance imaging

High-resolution susceptibility weighted MR imaging at high field strength provides excellent depiction of venous structures, blood products, and iron deposits, making it a promising complementary imaging modality for cerebral cavernous malformations (CCMs). Although already introduced in 1997 and being constantly improved, susceptibility weighted imaging is not yet routine in clinical neuroimaging protocols for CCMs. In this article, the authors review the recent literature dealing with clinical and scientific susceptibility weighted imaging of CCMs to summarize its prospects and drawbacks and provide their first experience with its use in ultra–high field (7-T) MR imaging.

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.

Supratentorial cavernous malformations in eloquent and deep locations: surgical approaches and outcomes. Clinical article

OBJECT

Resection of cavernous malformations (CMs) located in functionally eloquent areas of the supratentorial compartment is controversial. Hemorrhage from untreated lesions can result in devastating neurological injury, but surgery has potentially serious risks. We hypothesized that an organized system of approaches can guide operative planning and lead to acceptable neurological outcomes in surgical patients.

METHODS

The authors reviewed the presentation, surgery, and outcomes of 79 consecutive patients who underwent microresection of supratentorial CMs in eloquent and deep brain regions (basal ganglia [in 27 patients], sensorimotor cortex [in 23], language cortex [in 3], thalamus [in 6], visual cortex [in 10], and corpus callosum [in 10]). A total of 13 different microsurgical approaches were organized into 4 groups: superficial, lateral transsylvian, medial interhemispheric, and posterior approaches.

RESULTS

The majority of patients (93.7%) were symptomatic. Hemorrhage with resulting focal neurological deficit was the most common presentation in 53 patients (67%). Complete resection, as determined by postoperative MR imaging, was achieved in 76 patients (96.2%). Overall, the functional neurological status of patients improved after microsurgical dissection at the time of discharge from the hospital and at follow-up. At 6 months, 64 patients (81.0%) were improved relative to their preoperative condition and 14 patients (17.7%) were unchanged. Good outcomes (modified Rankin Scale score ≤ 2, living independently) were achieved in 77 patients (97.4%). Multivariate analysis of demographic and surgical factors revealed that preoperative functional status was the only predictor of postoperative modified Rankin Scale score (OR 4.6, p = 0.001). Six patients (7.6%) had transient worsening of neurological examination after surgery, and 1 patient (1.3%) was permanently worse. There was no surgical mortality.

CONCLUSIONS

The authors present a system of 13 microsurgical approaches to 6 location targets with 4 general trajectories to facilitate safe access to supratentorial CMs in eloquent brain regions. Favorable neurological outcomes following microsurgical resection justify an aggressive surgical attitude toward these lesions.

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.

MR imaging of midbrain pathologies

The spectrum of pathologic processes affecting the midbrain features some differences to other brain areas. The midbrain is exposed to traumatic alterations due to its position between the tentorial edges, and some neurodegenerative and metabolic-toxic diseases may typically involve the midbrain. Isolated midbrain ischemia is rare, whereas the midbrain is typically part of the "top of the basilar" syndrome. Primary midbrain tumors are also infrequent and often show a benign clinical course. Apart from multiple sclerosis other inflammatory autoimmune processes and some infectious agents predominantly affect the brainstem including the midbrain. This review discusses the different pathologic processes of the midbrain, i.e., infarction, hemorrhage and trauma, inflammation, toxic and metabolic diseases, neurodegeneration, neoplastic diseases, as well as pathologies typically involving the perimesencephalic cisterns.

Supracerebellar-Supratrochlear and Infratentorial-Infratrochlear Approaches

OBJECTIVE

Lateral supracerebellar-infratentorial approaches are established for lesions in ambient cistern and posterolateral midbrain, but published surgical experiences do not describe results with this approach in the sitting position. Gravity retraction of the cerebellum opens this surgical corridor and dramatically alters exposure, creating 2 variations of the lateral supracerebellar-infratentorial approach: the supracerebellar-supratrochlear approach and the infratentorial-infratrochlear approach.

METHODS

We reviewed our experience treating cavernous malformations and arteriovenous malformations (AVMs) of the posteroinferior thalamus and posterolateral midbrain by use of supracerebellar-supratrochlear and infratentorial-infratrochlear approaches. Microsurgical technique, clinical data, radiographic features, and neurological outcomes were evaluated.

RESULTS

During an 11-year surgical experience with 341 cavernous malformation patients and 402 AVM patients, 8 patients were identified, 6 with cavernous malformations and 2 with AVMs. Infratentorial-infratrochlear approaches were used in 4 patients (50%), including 3 with inferolateral midbrain cavernous malformations. Supracerebellar-supratrochlear approaches were used in 4 patients (50%), including 2 with posterior thalamic lesions surfacing on pulvinar. Resections were radiographically complete in all cases. There were no new, permanent neurological deficits, nor were there any medical or surgical complications. There has been no evidence of rebleeding or recurrence.

CONCLUSIONS

Gravity retraction of the cerebellum transforms the lateral supracerebellar-infratentorial approach, enhancing exposure and approach trajectories that can be achieved with patients in prone or lateral positions. The increased upward viewing angle of the supracerebellar-supratrochlear approach accesses the posteroinferior thalamus. The increased downward-viewing angle of the infratentorial-infratrochlear approach accesses cerebellomesencephalic fissure and posterolateral midbrain. These approaches open wide corridors for safe surgical resection of symptomatic cavernous malformations and AVMs.

Surgical management of brainstem cavernomas: selection of approaches and microsurgical techniques

This study reviewed surgical experience with brainstem cavernomas in an attempt to define optimal surgical approaches and risks associated with surgical management. Clinical courses were retrospectively reviewed for 36 consecutive patients (12 men, 24 women; mean age, 42 years) who underwent microsurgical resection of brainstem cavernomas between 1996 and 2006. Medical records, surgical records, and neuroimaging examinations were evaluated. All 36 patients presented with > or =1 hemorrhage from the cavernomas and preoperatively displayed some neurological symptoms. Surgical approach was midline suboccipital for 16 pontine and/or medullary cavernomas under the floor of the fourth ventricle, retrosigmoid for 10 lateral mesencephalic, pontine, and/or medullary cavernomas, occipital transtentorial for 2 thalamomesencephalic and 3 mesencephalic cavernomas, combined petrosal for 2 pontine cavernomas, and other for 3 cavernomas. Complete resection according to postoperative magnetic resonance imaging was achieved in 33 of 36 patients. No mortality was encountered in this study. New neurological deficit occurred in the early postoperative period for 18 patients, but was transient in 15 of these. Neurological state as of final follow-up was improved in 16 patients (44%), unchanged in 17 (47%), and worsened in 3 (8%) compared with preoperatively. In conclusion, symptomatic brainstem cavernomas should be considered for surgical treatment. Careful selection of the optimal operative approach and a meticulous microsurgical technique are mandatory.

Lateral Transpeduncular Approach to Intrinsic Lesions of the Rostral Pons

Objective:

We describe the lateral transpeduncular approach to access lesions in the rostral pons. The surgical indications and technique are discussed in the context of an illustrative case and pertinent anatomic considerations.

Methods:

A 38-year-old man with acute right hemiparesis and bulbar symptoms had a left pontine hemorrhage with an associated cavernous malformation and venous anomaly. There was no pial or ependymal representation of the lesion. To avoid disruption of eloquent structures, the pia was entered in the posterolateral aspect of the middle cerebellar peduncle. Subsequent dissection was guided by stereotactic neuronavigation in a ventromedial trajectory along the course of the pontocerebellar fibers.

Results:

The cavernous malformation was resected completely without procedure-related morbidity. The patient’s preoperative deficits slowly improved to a functionally independent state.

Conclusion:

The lateral transpeduncular approach may be used to access intrinsic lesions of the rostral pons with relatively low morbidity. Stereotactic neuronavigation and intra-operative electrophysiological monitoring are important surgical adjuncts to guide dissection and lesion extirpation. Candidate selection, microsurgical technique, and pragmatic treatment goals remain fundamental to optimal patient outcomes.

Supracerebellar Infratentorial Approach to Cavernous Malformations of the Brainstem

OBJECTIVE

The supracerebellar infratentorial (SCIT) approach can be performed at the midline (median variant), lateral to the midline (paramedian variant), or at the level of the angle formed by the transverse and sigmoid sinuses (extreme lateral variant). We analyzed our experience with SCIT approaches for the surgical treatment of cavernous malformations of the brainstem (CMBs).

METHODS

Demographic, clinical, radiologic, and surgical data from 45 patients (20 males and 25 females; mean age, 36.2 years) with CMBs surgically removed through SCIT approaches were reviewed retrospectively. Anatomic information was explored using cadaver head dissection.

RESULTS

Twenty-three lesions were in the midbrain, 3 were at the midbrain and extended to the thalamus, 9 were at the pontomesencephalic junction, and 10 were in the upper pons. All patients presented with hemorrhage. The median variant was used in 13 patients, the paramedian variant in 9, and the extreme lateral variant in 23. Intraoperatively, all CMBs were associated with a developmental venous anomaly. At last follow-up, 88% of the patients were the same or better. After a mean follow-up of 20 months, their mean Glasgow Outcome Scale score was 4.1.

CONCLUSION

SCIT approaches provide excellent exposure to CMBs located at the posterior incisural space, not only in the midline but also in the posterolateral surface of the upper pons and midbrain. Careful preoperative planning and neuronavigational assistance are needed to determine the best angle of attack and trajectory for SCIT approaches. Refined microsurgical techniques are paramount to achieve safe surgical removal of CMBs with good outcomes.

Epileptogenic temporal cavernous malformations: operative strategies and postoperative seizure outcomes

Operative treatment of epileptogenic cavernous malformations (CM) continues under debate. Most studies focus on surgery for supratentorial CM in general. For temporal lobe CM, surgical decision-making concerns in particular whether to perform lesionectomy alone or the additional excision of mesial temporal structures. The purpose of this case series was to evaluate operative strategies used to treat epileptogenic temporal CM and to report resultant postoperative seizure outcomes. Twelve consecutive cases of patients with medically intractable epilepsy who underwent operation for temporal CM between 1996 and 2006 were retrospectively reviewed. When the temporal CM directly invaded the hippocampus or amygdala, the affected structures were resected in addition to the lesion; when the CM was located in the superficial temporal cortex, and there was no radiographic evidence of hippocampal sclerosis, lesionectomy alone was done; with CM located between the superficial temporal cortex and the mesial temporal region, other factors were considered in decision-making, such as lesion proximity to the deep mesiotemporal structures and preoperative epilepsy duration. For six of the twelve patients, extended lesionectomy (EL) alone was done; for the other six, tailored anteromedial temporal resection with hippocampectomy and/or amygdalectomy was performed in addition to EL. Postoperatively, 11 patients - all with preoperative VEM demonstrating electroclinical seizure patterns concordant with lesion location - were seizure-free. We conclude that epileptogenic temporal CM are surgically remediable, when approached with the above operative strategies and presurgical VEM. On the basis of these postoperative seizure control results, we recommend consideration of concurrent resection of mesial temporal structures with EL for certain temporal CM.

Brain stem cavernous malformations

We retrospectively reviewed the clinical experience of 30 patients with brain stem cavernous malformations (BSCM) treated operatively and non-operatively at our hospital between 1983 and 2005 to elucidate the natural history of BSCM and the factors that affect surgical outcome. Inpatient charts, imaging studies, operative records, and follow-up results were evaluated. The average follow up was 48.5 months. Twenty-two patients (73.3%) received surgical extirpation and of these 86.4% improved or stabilized and 13.6% deteriorated with permanent or severe morbidity. There was no mortality. Size, preoperative status, and surgical timing were factors related to surgical outcome. In the non-operative group, 50% of the patients were the same or better, 25% deteriorated, and 25% died. With appropriate patient selection, resection of BSCM can be achieved with acceptable morbidity compared with the ominous natural history of these lesions.

Intracranial haemorrhage in pregnancy

Intracranial haemorrhage (ICH) is a rare, yet potentially devastating event in pregnancy. There is a risk of maternal mortality or morbidity and a significant risk to the unborn child. The risk of haemorrhage increases during the third trimester and is greatest during parturition and the puerperium. ICH can be extradural, subdural, subarachnoid or intraparenchymal. Causes of bleeding include trauma, arteriovenous malformations, aneurysms, preeclampsia/eclampsia and venous thrombosis. Urgent neurosurgical conditions generally outweigh obstetric considerations in management decisions, although anaesthetic and surgical modifications can be made to minimize adverse effects to the fetus.

Familial cerebral cavernous malformations: Rio de Janeiro study and review of the recommendations for management

OBJECTIVE

Multiple cerebral cavernous malformation (CCM) is the hallmark of familial presentation of cavernous malformation in the brain. We describe an ongoing Familial Cerebral Cavernous Malformation Project in the Rio de Janeiro state showing genetic profile and the pattern of emergent neuroimaging findings of this particular population besides a review of the updated recommendations for management of familial CCM versus patients harboring sporadic lesions.

METHOD

Four families of our cohort of 9 families were genetically mapped showing mutational profile linked to CCM1. The neuroimaging paradigm was shifted from T2*gradient-echo (GRE) sequence to susceptibility weighting MR phase imaging (SWI).

RESULTS

Only two index cases were subjected to surgery. There was no surgical intervention in any of the kindreds of our entire cohort of 9 families of our Neurovascular Program within seven years of follow-up. The genetic sequencing for mutational profile in four of these families has demonstrated only CCM1 gene affected. Our management of the familial CCM is according to the review of the literature recommendations.

CONCLUSIONS

The Project of Familial Cerebral Cavernous Malformations of Rio de Janeiro detected mutations of the gene CCM1 in the first four families studied. Familial cavernous malformation are to be settled apart from the more common sporadic lesion. A set of recommendations was searched for in the literature in order to deal with these specific patients and kindreds.

Management of pediatric brainstem cavernous malformations: experience over 20 years at the hospital for sick children

OBJECT

Because of their location and biological behavior, brainstem cavernous malformations (CMs) pose a formidable clinical challenge to the neurosurgeon. The optimal management of these lesions requires considerable neurosurgical judgment. Accordingly, the authors reviewed their experience with the management of pediatric brainstem CMs at the Hospital for Sick Children.

METHODS

The authors performed a retrospective chart review of pediatric patients who had received diagnoses of a brainstem CM at the Hospital for Sick Children over the past 20 years.

RESULTS

Twenty patients were diagnosed with brainstem CMs. The mean age at diagnosis was 10.1 +/- 5.4 years, and the patients included 13 boys and 7 girls. The mean maximal diameter of the CM was 14.3 +/- 11.2 mm. The lesions were evenly distributed on the right and left sides of the brainstem with 4 midbrain, 13 pontine, and 3 medullary lesions. Seven patients underwent surgery for the management of their CMs, with a mean age at presentation of 5.2 years, and a mean CM size of 21.0 mm. Of note from the surgical group, 2 patients had a family history of CMs, 2 lesions were medullary, the CM reached a pial surface in 6 of 7 patients, and 6 of 7 lesions were located on the right side. The mean age at presentation among the 13 patients in the nonsurgical group was 12.7 years, and the mean CM size was 10.6 mm. Seven of these patients had a prior history of radiation for tumor, and only 3 had lesions that reached a pial surface.

CONCLUSIONS

The management of brainstem CMs in children is influenced by multiple factors. The majority of patients received conservative management and tended to be asymptomatic with smaller lesions. Patients with larger lesions and direct pial contact, in whom symptoms arose at a younger age were more likely to undergo surgical management. A history of familial CM was also a predictor for receiving surgical treatment. No patients with a prior history of radiation therapy underwent surgery for CMs. The presence of multiple lesions seemed to have no impact on the type of management chosen. Patients who underwent surgery did suffer morbidity related to the procedure, and tended to improve clinically over time. Conservative management was associated with new deficits arising in children, some of which improved with time. Consideration of many clinical and radiological parameters is thus prudent when managing the care of children with brainstem CMs.

The putative role of the venous system in the genesis of vascular malformations

Recent clinical and experimental evidence has challenged the traditional concept of the venous system as a “passive” element in the genesis and evolution of intracranial vascular malformations. The authors review the clinical and experimental evidence linking the venous system and its anomalies to the genesis of various intracranial vascular malformations, including dural arteriovenous fistulas, cavernous malformations, parenchymal arteriovenous malformations, and capillary telangiectasia. They also describe the potential significance of different associations of these vascular anomalies.

Spinal accessory nerve cavernous malformation

We present the first reported case of a spinal accessory nerve cavernous malformation. A 54-year-old Caucasian male presented with a several-year history of progressive, vague bilateral upper and lower extremity paresthesias and pain. MRI of the spine revealed a heterogenously enhancing mass in the dorsal aspect of the spinal canal at the level of the atlas with mild spinal cord compression. The lesion was resected and upon gross and histologic examination it was a cavernous malformation embedded within a branch of the spinal accessory nerve. Post-operatively, the patient had no complications and some improvement in his symptoms. To our knowledge, this is the first report of a patient with a spinal accessory nerve cavernous malformation, and this should be considered in the differential of lesions in the craniocervical region.

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.

Cavernous hemangioma of the mesencephalon: tonsillouveal transaqueductal approach

OBJECTIVE

Recent advances in microsurgical techniques facilitate surgical resection of brainstem lesions that were previously considered inoperable. In this article we present, for the first time, the tonsillouveal transaqueductal approach to access a progressively symptomatic cavernoma within the depth of the tegmentum of the mesencephalon.

METHODS

A 52-year-old woman presented with a history of slowly progressive right-sided hemiparesis and ataxia. On magnetic resonance imaging, a relatively large cavernoma involving the tegmentum of the mesencephalon was shown. The sylvian aqueduct was patent and there was no secondary ventriculomegaly. The patient underwent surgery via a suboccipital craniotomy and C1 laminectomy. The right tonsillouveal and medullotonsillar spaces were opened to the level of the choroidal point of the posteroinferior cerebellar artery. The tela choroidea was incised from the foramen of Magendie to the telovelar junction. Looking through the aqueduct and at a point 5 mm superior to its inferior inlet, there was a small cherry-like blister protruding into the aqueductal anterior surface. This was used as an entry point to access the cavernoma. The space around the cavernoma was gently dissected and the cavernoma was circumferentially coagulated to shrink it in a concentric manner toward its center.

RESULTS

The total removal of the lesion was achieved and the histopathological findings were consistent with a cavernoma. As a result of noncommunicating hydrocephalus, the patient needed a ventriculoperitoneal shunt. The 1-year postoperative neurological examination was consistent with preoperative findings.

CONCLUSION

This report shows, for the first time, direct surgical removal of a cavernous hemangioma in the mesencephalic tegmentum via the aqueduct. This approach adds to contemporary microneurosurgery, respecting functional anatomy and minimizing neurological deficits.

DEVELOPMENTAL VENOUS ANOMALIES

DEVELOPMENTAL VENOUS ANOMALIES (DVAs), formerly known as venous angiomas, have become the most frequently diagnosed intracranial vascular malformation. DVAs are currently considered congenital cerebrovascular anomalies with mature venous walls that lack arterial or capillary elements. They are composed of radially arranged medullary veins, which converge in an enlarged transcortical or subependymal collector vein, and have characteristic appearances (caput medusae) on magnetic resonance imaging and angiography. DVAs were once thought to be rare lesions with substantial potential for intracerebral hemorrhage and considerable morbidity. The prevalence of incidental and asymptomatic DVAs has been more apparent since the advent of magnetic resonance imaging; recent cohort studies have challenged the once-held view of isolated DVAs as the cause of major neurological complications. The previously reported high incidence of intracerebral hemorrhage associated with DVAs is currently attributed to coexistent, angiographically occult cavernous malformations. Some patients may still have noteworthy neurological morbidity or die as a result of acute infarction or hemorrhage directly attributed to DVA thrombosis. DVAs can coexist with cavernous malformations and arteriovenous malformations. Such combination or transitional forms of malformations might suggest common pathways in pathogenesis. Recent data support a key role for DVAs in the pathogenesis of mixed vascular malformations.

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.

The supracarotid-infrafrontal approach: surgical technique and clinical application to cavernous malformations in the anteroinferior Basal Ganglia

OBJECTIVE

Many symptomatic cavernous malformations deep in the anteroinferior basal ganglia are deemed to be inoperable and managed conservatively because transcortical, transsylvian-transinsular, and transcallosal approaches are unsuitable. We present an approach to these lesions through the supracarotid triangle, between ascending perforators, and through the basomedial frontal lobe.

METHODS

The supracarotid-infrafrontal approach incorporates an orbitozygomatic craniotomy, wide microsurgical exposure of the supracarotid triangle, dissection of perforating arteries, and image-guided resection through the posterior part of the medial orbital gyrus and anterior perforated substance.

RESULTS

During 10 years of surgical experience with 269 patients with cavernous malformations, 5 patients were identified with lesions in the basal ganglia that were resected completely using the supracarotid-infrafrontal approach. Transient neurological deficits were observed postoperatively in 2 patients, and all patients had excellent outcomes (modified Rankin Scale score of 0 or 1; mean duration of follow-up, 1.4 years).

CONCLUSION

Cavernous malformations in the anteroinferior basal ganglia come to the brain surface directly behind the internal carotid artery bifurcation, and the supracarotid-infrafrontal trajectory best matches the lesions' axes. The surgical corridor runs between perforating arteries, but entrance into these lesions opens additional working space that is not normally present when the approach is used with aneurysms. Careful handling of crossing and ascending perforating arteries is critical, as is delicate dissection of the lesion's superior pole where it abuts the internal capsule.

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.

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.

Completely endoscopic resection of intraparenchymal brain tumors

Object

The authors introduce a novel technique of intraparenchymal brain tumor resection using a rod lens endoscope and parallel instrumentation via a transparent conduit.

Methods

Over a 4-year period, 21 patients underwent completely endoscopic removal of a subcortical brain lesion by means of a transparent conduit. Image guidance was used to direct the cannulation and resection of all lesions. Postoperative MR imaging or CT was performed to assess for residual tumor in all patients, and all patients were followed up postoperatively to assess for new neurological deficits or other surgical complications.

Results

The histopathological findings were as follows: 12 metastases, 5 glioblastomas, 3 cavernous malformations, and 1 hemangioblastoma. Total radiographically confirmed resection was achieved in 8 cases, near-total in 6 cases, and subtotal in 7 cases. There were no perioperative deaths. Complications included 1 infection and 1 pulmonary embolus. There were no postoperative hematomas, no postoperative seizures, and no worsened neurological deficits in the immediate postoperative period.

Conclusions

Fully endoscopic resection may be a technically feasible method of resection for selected subcortical masses. Further experience with this technique will help to determine its applicability and safety.