Retractorless surgery for intracranial aneurysms

Microsurgical clipping of intracranial aneurysms often requires access to the subarachnoid space deep in the brain. In the past, fixed retractors have been used to maintain the surgical corridor. However, studies have shown that fixed retraction leads to brain injuries. Here we present strategies to replace conventional fixed retractor blades with dynamic retraction so that the brain is no longer under constant pressure. We show that dynamic retraction without fixed retractors, when combined with optimal patient position and neuroprotective anesthetics, can provide the surgeon with adequate visualization of aneurysms and excellent surgical outcomes.

Endovascular management of distal ACA aneurysms: single-institution clinical experience in 22 consecutive patients and literature review

BACKGROUND AND PURPOSE

Distal ACA aneurysms remain difficult to treat with endovascular therapy, but improved technology and experience allows for the treatment of some of these aneurysms with excellent results. The purpose of this study was to assess the status of endovascular treatment of distal ACA aneurysms by comparing our results with recent endovascular and microsurgical series of distal ACA aneurysms.

MATERIALS AND METHODS

Between 2000 and 2008, a total of 22 consecutive patients (14 women; mean age, 58.4 years) with distal ACA aneurysms underwent coil placement at Barrow Neurological Institute. Clinical presentations, radiographic findings, endovascular management, and outcomes were reviewed retrospectively.

RESULTS

Of the 22 patients, 13 (59%) presented with subarachnoid hemorrhage. Six patients were HH grade I or II, 1 was grade III, 5 were grade IV, and 1 was grade V. Frontal lobe hematomas occurred in 5 patients with ruptured aneurysms. The mean aneurysm size was 7.5 mm (range, 2.8-25 mm); 55% were smaller than 7 mm. Twelve aneurysms (55%) arose from the origin of the callosomarginal artery (55%). Complete occlusion was achieved in 50% of the cases and near-complete occlusion in 45%. The few periprocedural complications included 1 retroperitoneal hematoma and 1 intraoperative rupture. Four patients had thromboembolic events adequately treated intraprocedurally with abciximab. No deaths occurred in the patients treated.

CONCLUSIONS

The characteristics of the patients and aneurysms treated in our series were comparable to previous reports of endovascular treatment of ACA aneurysms with respect to rupture status. Periprocedural morbidity and mortality rates in our series fared well compared with previous reports, as did our combined rate of complete or near-complete occlusions. Recent advances in endovascular devices and techniques have improved outcomes of distal ACA aneurysms.

Internal carotid artery sacrifice for radical resection of skull base tumors

When dealing with skull base tumors that encase the internal carotid artery (ICA), the surgeon must decide between ICA preservation and incomplete tumor resection, or radical resection with ICA sacrifice. In our experience with more than 300 anterior skull base tumors, the ICA was sacrificed in only 10 patients. These tumors were malignant, except for one meningioma that occluded the ICA and produced translent ischemic symptoms. All patients had the ICA resected with the tumor, and all patients underwent revascularization (cervical ICA-MCA saphenous bypass, n = 4; cervical-to-supraclinoid bypass, n = 1; petrous-to-supraclinoid bypass, n = 3; bonnet bypass, n = 2). This small patient series reflects our practice of preserving the ICA whenever possible. We recommend preserving the ICA with benign tumors because they do not invade the artery, or do so only to a limited extent. In addition, similar rates of tumor recurrence are seen after aggressive resection with or without ICA sacrifice. In contrast, we recommend radical tumor resection and sacrifice of the ICA with malignant tumors because they directly threaten the integrity of the ICA and the patient's survival. The ICA should not be considered a limitation to radical tumor resection because the ICA can be reconstructed safely with an appropriate bypass procedure.

Return of olfaction after gross total resection of an olfactory groove meningioma: case report

Patients with olfactory, groove meningiomas may present with anostnia, Surgery in patients with intact olfaction can also lead to anosmia when the olfactory nerves are sacrified. Olfaction can be preserved by using the prerional approach and microsurgical technique. To our knowledge; however, the recovery of olfaction after resection of an olfactory groove meningroma has not been reported. We therefore describe a patient who presented with anosmia whose evaluation revealed a large olfactory groove meningioma. She underwent a bifrontal approach for microsurgical gross bilateral excision of the tumor. At her 6-month follow-up examination, her olfaction, as measured by formal testing, had recovered.

Medulloblastoma presenting with tentorial "dural-tail" sign: is the "dural-tail" sign specific for meningioma?

To the best of our knowledge, the association of a medulloblastoma with a "dural-tail" sign has not been previously reported. A 24-year-old male developed severe headaches and right-sided dysmetria that worsened over 1 month. Magnetic resonance (MR) imaging of the brain demonstrated a heterogeneously enhancing lesion in the posterior fossa. The lesion appeared to be tentortally-based and exhibited a characteristic "dural-tail" sign, which is considered pathognothonic for meningioma. Cerebellar tonsil ectopia and hydrocephalus were also present. The presumptive diagnosis of tentorial meningioma was made. The lesion was resected by a posterior fossa approach. At surgery, the appearance of the tumor was inconsistent with the diagnosis of meningioma, and histopathologic evaluation yielded the diagnosis of medulloblastonia. This case and the literature demonstrate that malignant tumors can present with the characteristic MR imaging appearance of a meningioma. This possibility must be considered when treatment is planned, especially if a nonoperative course is favored.

Combined approach for lesions involving the cerebellopontine angle and skull base: experience with 30 cases

This article presents a series of 30 patients who underwent a combination of the subtemporal and posterior fossa approaches for exposure of lesions in the clivus or medial petrous region. This combined supra- and infratentorial approach is divided into three variations with progressively greater petrous bone resection to increase exposure of the clivus and medial petrous region. The approach has been divided into petrous bone resection with preservation of hearing (retrolabyrinthine), greater petrous bone resection with sacrifice of hearing (translabyrinthine), and finally maximum petrous drilling with sacrifice of hearing along with transposition of the facial nerve (transcochlear). Ninety-three percent of the cases returned to their premorbid occupations.

Persistent lower abdominal pain induced by long peritoneal shunt catheter

Persistent abdominal pain directly induced by a peritoneal catheter of a ventriculoperitoneal shunt, which is associated with no other complications such as bowel perforation, pseudocyst or infection, has not been previously reported. A 65-year-old woman with hydrocephalus developed persistent lower abdominal pain radiating to the perineal area after shunt insertion. Radiography suggested that the distal end of a peritoneal catheter was located in a cul-de-sac of the pelvis. Otherwise, all studies were negative for shunt infection, fluid collection, or other abdominal and pelvic events. The patient's pain resolved completely after surgery in which the peritoneal catheter was shortened. In the presence of unexplained, persistent lower abdominal pain after shunt placement, the need to shorten the peritoneal catheter should be considered.

Developmental venous anomaly, cavernous malformation, and capillary telangiectasia: spectrum of a single disease

Developmental venous anomalies (DVAs), cavernous malformations, and capillary telangiectasias are related vascular malformations of the central nervous system. Mixed lesions of the central nervous system vasculature have been reported in a host of combinations, including many possible concomitant combinations of cavernous malformations, venous anomalies, capillary telangiectasias, and arteriovenous malformations (AVMs). We describe the natural history of disease in a female with developmental venous anomaly, cavernous malformation, and capillary telangiectasias appearing in sequence.

Intraoperative angiography for hunterian ligation of a recurrent basilar aneurysm

Cerebral aneurysms often recur after selective endovascular treatment with detachable coils and are usually treated by recoiling. Sometimes, however, surgical treatment is required, and application of the clip can be difficult. Evacuation of embolic material risks injuring eloquent structures or perforators, especially in the posterior circulation. In such cases parent vessel occlusion for reversal of flow might be an option. If collateral flow is adequate, an additional bypass is not required. When using this technique, known as Hunterian ligation, intraoperative monitoring such as electrophysiological monitoring and intraoperative angiography can be of great help and are advisable. We describe this procedure and related intraoperative considerations in one case report.

Treatment of Recurrent Previously Coiled Anterior Circulation Aneurysm with Minimally Invasive Keyhole Craniotomy: Report of Two Cases

The use of minimally invasive techniques has not yet been reported for the treatment of recurrent aneurysms after coil embolization. A 47-year-old man with a long history of headaches had an anterior communicating aneurysm that had previously been coil embolized. Three-year follow-up angiography showed a significant recurrence. A 50-year-old woman with subarachnoid hemorrhage and acute visual loss underwent coil embolization of a large ophthalmic artery aneurysm, which recurred 3 months later. In both cases, a keyhole fronto-orbital one-piece craniotomy was performed. In the first patient, the aneurysm was clip ligated. The coil mass, which had eroded through the dome, was excised. In the second patient, the anterior clinoid was removed and the aneurysm was clip ligated. Postoperative angiography showed no residual aneurysm and no evidence of branch or parent vessel compromise in either patient. Both patients had an uncomplicated postoperative course. Recurrent previously coiled aneurysms are technically challenging to treat. A minimal fronto-orbital craniotomy provides a sufficiently capacious working space for successful treatment of some recurrent aneurysms of the anterior circulation.

Long-term follow-up of giant serpentine MCA aneurysm treated with EC-IC bypass and proximal occlusion

Giant serpentine aneurysms are a rare but important subset of giant aneurysms, with unique management considerations. We present long-term follow-up clinical and imaging features of a giant serpentine middle cerebral artery lesion treated with extracranial-intracranial bypass and proximal occlusion more than a decade earlier. Calcification of the obliterated aneurysm sac and durability of this management strategy are demonstrated.

Spontaneous ventriculostomy in a patient with obstructive hydrocephalus

BACKGROUND

Spontaneous ventriculostomy related to progressive obstructive hydrocephalus is rare. Radiologic demonstration of such a phenomenon can be delineated with magnetic resonance imaging (MRI) and cine MRI.

CASE PRESENTATION

A 59-year-old woman with a known tectal glioma and symptoms of chronic hydrocephalus developed progressively worsening headaches. During follow-up, she noted spontaneous relief of her headaches. Follow-up cine MRI demonstrated a spontaneous ventriculostomy via the floor of the third ventricle.

INTERPRETATION

Clinicians should be aware of spontaneous ventriculostomy demonstrable on cine MRI because it may obviate the need for a CSF diversion procedure.

Endolymphatic sac tumor: unique features of two cases and review of the literature

Endolymphatic sac tumors (EST) are rare intracranial tumors originating from the pars rugosa of the endolymphatic sac. Although typically described as histologically nonaggressive lesions, nevertheless they are termed adenocarcinomas and often become locally invasive. We report two patients with histologically proven EST with unique clinical features: the first pediatric case of an EST in an 11-year-old patient whose complaints started at the age of seven; and, a second patient, a 43-year-old man, the first report of metastatic EST which appeared in a remote location from the original site of surgery. Both patients underwent gamma-knife radiosurgery for recurrent tumor. This treatment has not been described previously for these tumors. Both patients have a follow-up of 7 years. Although not disease free they remain neurologically stable. We review the literature on EST.

Associated arteriovenous malformation of the orbit and brain: a case of Wyburn-Mason syndrome without retinal involvement. Case report

Wyburn-Mason syndrome is a rare condition associated with multiple cerebral arteriovenous malformations. The disease, also called retinoencephalofacial angiomatosis, includes lesions of the retina, brain, and skin. This disorder stems from a vascular dysgenesis of the embryological anterior plexus early in the gestational period when the primitive vascular mesoderm is shared by the involved structures. The timing of the insult to the embryonic tissue determines which structures are affected. Extensions of the lesions vary widely but cutaneous lesions are unusual. Among reports in the literature, only three cases appear to have manifested without retinal involvement. The authors report the fourth case of Wyburn-Mason syndrome in which there was no retinal involvement and the first to involve neither the retina nor the face.

The role of cerebral revascularization in patients with intracranial aneurysms

Cerebral revascularization offers an important adjunct to parent-vessel ligation in the treatment of large and otherwise inaccessible intracranial aneurysms. Good or excellent outcomes can be expected in approximately 80% of patients. Poor outcomes and ischemic complications were highest in posterior circulation lesions. Cranial neuropathies from mass effect associated with giant aneurysms of the cavernous and intradural internal carotid artery will improve and be cured in the majority of patients treated with universal revascularization approach. In combination with open parent vessel ligation or endovascular occlusion, durable protection from subarachnoid hemorrhage can be achieved.

Reporting terminology for brain arteriovenous malformation clinical and radiographic features for use in clinical trials

“If you wish to converse with me,” said Voltaire, “define your terms.” How many a debate would have been deflated into a paragraph if the disputants had dared to define their terms!

Will Durant: The Story of Philosophy

Animal model for cerebral arteriovenous malformation

BACKGROUND

The present study was conducted to establish an animal model for the investigation of the pathophysiology and haemodynamics of cerebral arteriovenous malformation (AVM) but also to assess therapeutic aspects.

METHOD

For anatomic and haemodynamic reasons, dogs were chosen as the animal model. An arteriovenous fistula was created by interposing a segment of the superficial temporal artery between one of the main branches of the middle cerebral artery and the dorsal sagittal sinus. A temporal muscle graft supplied by this artery was implanted intracerebrally in the ischaemic area.

FINDINGS

The angiographic and histopathologic findings obtained in the animal model are comparable with the situation found in intracerebral AVM in humans.

INTERPRETATION

The animal model of intracerebral AVM established in this study allows for further investigation of the pathophysiology and dynamics of this disorder. It may help to develop better therapeutic options and thus improve the prognosis of affected patients.

Assessment of silent embolism from carotid endarterectomy by use of diffusion-weighted imaging: work in progress

BACKGROUND AND PURPOSE

Transcranial Doppler studies have suggested that microemboli are released into the arterial circulation during the majority of carotid endarterectomy (CEA) procedures. This, together with the observation that neuropsychological performance may decline postoperatively, has led to concern that cerebral infarction may occur unrecognized during CEA. Our objective was to examine this risk with diffusion-weighted imaging, a technique that is highly sensitive to acute cerebral infarction.

METHODS

Eighteen participants (median age, 68 years; age range, 56-87 years) were assessed with diffusion-weighted imaging and the National Institutes of Health Stroke Scale before and after CEA. Imaging was performed using single-shot echo-planar imaging with a maximum diffusion sensitivity of b = 1000 s/mm(2) applied to three orthogonal planes. Preoperative imaging was performed a median of 2.5 hours before surgery (range, 0.5-12.5 hours) and 15 hours after surgery (range, 1.5-58.5 hours). Two neuroradiologists independently interpreted the diffusion-weighted images, blinded to operative status and clinical findings.

RESULTS

There was no diffusion-weighted imaging evidence of silent embolism in this series of 18 participants (95% confidence interval limits, 0 to 10%). Clinical complications were confined to one case of confusion occurring after CEA; the diffusion-weighted imaging results were normal in this case.

CONCLUSION

There is no evidence from our series that silent cerebral infarction is a common occurrence during CEA. These data provide further support for the safety of CEA.

Osteosarcoma of the temporal fossa with hemorrhagic presentation: case report

OBJECTIVE AND IMPORTANCE

Excluding tumors of hematopoietic origin, osteosarcomas are the most common bone tumor, although involvement of the brain or cranial base is rare.

CLINICAL PRESENTATION

A 16-year-old girl with an osteosarcoma of the temporal fossa presented with an intracerebral hemorrhage. The management strategy of this lesion, including the operative interventions, is described.

INTERVENTION

Several modes of treatment were undertaken, including radical resection of the cranial base lesion and excision of the cavernous sinus after a cervical internal carotid artery-to-middle cerebral artery vein bypass graft.

CONCLUSION

The patient was alive and without evidence of disease 11 months after presentation but died shortly thereafter of complications related to adjuvant therapies.

Intracranial aneurysms and arterial hypertension: a review and hypothesis

BACKGROUND

Intracranial aneurysms and systemic arterial hypertension coexist in a high percentage of patients. The relationship between intracranial aneurysms and hypertension is poorly defined.

METHODS

Therefore, we reviewed the role of hypertension in the pathogenesis of saccular aneurysms as previously reported in clinical, experimental, and autopsy studies.

RESULTS

Among 24 relevant clinical and/or autopsy studies, the mean incidence of pre-existing hypertension was 43.5% in aneurysm patients compared to 24.4% in the normal population. Although definitive evidence is lacking, data from multiple types of investigations indicate that systemic arterial hypertension creates a greater risk for the development of intracranial aneurysms than previously believed. The underlying pathophysiological mechanism(s) are also poorly defined.

CONCLUSIONS

We propose a unifying hypothesis: Endothelial injury, occlusion of the vasa vasorum, and disruption of the synthesis of collagen and elastin are likely the most important factors in initiating the development of aneurysms. Chronic hypertension potentially affects all of these factors. Consequently, chronic hypertension may cause intimal thickening, necrosis of the tunica media, changes in the compositional matrix, and degeneration of the internal elastic lamina to develop in the arterial wall. These structural changes could cause a focal weakening in the arterial wall with resultant bulging. This theory accounts for the high incidence of intracranial aneurysms in the absence of any known associated hereditary or connective-tissue disease. Nor does it exclude the possibility of other etiological factors. From the perspective of prevention, however, it offers clear opportunities for prophylaxis.

Subfascial and submuscular methods of temporal muscle dissection and their relationship to the frontal branch of the facial nerve. Technical note

The microsurgical anatomy of the temporal and zygomatic branches of the facial nerve are presented along with related local vasculature (frontal and parietal branches of the superficial temporal artery [STA]) as encountered when using subfascial and submuscular temporal muscle dissection techniques for anterolateral craniotomies. Twenty sides were studied in 10 cadaveric specimens that had been previously injected with latex. The rami of the temporal and zygomatic branches of the facial nerve and branches of the STA were dissected out through pterional and orbitozygomatic approaches by using a submuscular or subfascial temporal muscle dissection technique. The three rami of the temporal branch of the facial nerve (the auricularis, frontalis, and orbicularis) were found to run within the galeal plane of the scalp. The zygomatic branch of the facial nerve was found to course deeper than the most caudal extension of the galea, known as the superficial musculoaponeurotic layer. The frontal branch of the STA served as an important landmark for the subfascial or submuscular dissections because excessive reflection of the scalp flap inferior to the level of this vessel would inadvertently injure the frontalis branch of the facial nerve. Subfascial and submuscular dissections of the temporal muscle offer an alternative to the interfascial technique during anterolateral craniotomies. Scalp and temporal dissection performed with careful attention to anatomical landmarks (frontal branch of the STA and the suprafascial fat pad) provides a safe and expeditious alternative to the traditional interfascial technique.

Cavernous malformation of the pineal region: short report and review of the literature

A case of a cavernous malformation of the pineal region is reported. Unique magnetic resonance images of a histologically-verified cavernous malformation of the pineal region are presented and the relevant literature on the subject is reviewed.

Diffuse vasospasm after pretruncal nonaneurysmal subarachnoid hemorrhage

Pretruncal (perimesencephalic) nonaneurysmal hemorrhage is a benign form of subarachnoid hemorrhage (SAH). Angiographic changes of vasospasm are uncommon in patients with this type of hemorrhage, and if vasospasm is present, it is mild and focal. We report two patients with pretruncal nonaneurysmal SAH who developed severe and diffuse vasospasm, expanding the clinical spectrum of this type of SAH. The first patient was a 40-year-old woman who suffered pretruncal nonaneurysmal SAH. Angiography performed on the seventh day post hemorrhage showed diffuse and severe vasospasm affecting both the anterior and the posterior circulation. The patient was treated with hypervolemia, and she remained asymptomatic. Follow-up angiography showed resolution of the vasospasm. The second patient was a 67-year-old woman who suffered pretruncal nonaneurysmal SAH. The results of the initial angiography were normal. Repeat angiography on the ninth day post hemorrhage showed severe vasospasm in the anterior circulation and moderate vasospasm in the posterior circulation. Nine hours later, the patient developed transient dysphasia, and she was treated with hypervolemia. Three days later, a transcranial Doppler examination showed normalization of blood velocities. The presence of diffuse and severe vasospasm does not exclude a diagnosis of pretruncal nonaneurysmal SAH.

Extreme lateral supracerebellar infratentorial approach to the posterolateral mesencephalon: technique and clinical experience

OBJECTIVE

Lesions situated posterolaterally along the mesencephalon present neurosurgeons with a special challenge. The midline and paramedian variations of the supracerebellar infratentorial approaches do not adequately expose this region. The subtemporal approach risks injury to the vein of Labbé. An extreme lateral supracerebellar infratentorial approach with more radical resection of bone superiorly and laterally, and skeletonization of the sigmoid and transverse sinuses, was used to approach lesions at this location in eight

METHODS

Five cavernous malformations, two juvenile pilocytic astrocytomas, and one peripheral superior cerebellar artery aneurysm located in this region were approached in eight patients. In this extreme lateral approach, the sigmoid sinus is unroofed more superiorly and the bone flap includes not only a posterior fossa craniotomy but also a portion that extends just above the transverse sinus. The dural opening is based along the transverse and sigmoid sinuses. After the cerebrospinal fluid has been drained, the lateral aspect of the brainstem is approached via the cerebellar surface. A proximal tentorial incision offers additional rostral exposure where needed.

RESULTS

Seven patients in this series underwent successful resection of their lesion. The remaining patient's aneurysm was clipped successfully with no major complications.

CONCLUSION

The extreme lateral supracerebellar infratentorial approach differs from the midline and paramedian supracerebellar infratentorial variants in the area of exposure, patient positioning, and location of the craniotomy. The technique is effective for approaching the posterolateral mesencephalon.

Long-term survival of a patient with invasive cranial base rhinocerebral mucormycosis treated with combined endovascular, surgical, and medical therapies: case report

OBJECTIVE

Rhinocerebral mucormycosis is a clinical syndrome resulting from an opportunistic infection caused by a fungus of the order Mucorales. The prognosis of rhinocerebral mucormycosis, once considered uniformly fatal, remains poor. Even with early diagnosis and aggressive surgical and medical therapy, the mortality rate is high. We present a patient with rhinocerebral mucormycosis involving the paranasal sinuses and cranial base who experienced long-term survival after multimodality treatment. Clinical characteristics of the disease are discussed, and the literature is reviewed.

CLINICAL PRESENTATION

A 24-year-old diabetic man presented with invasive rhinocerebral mucormycosis involving the paranasal sinuses, right middle fossa, and right cavernous sinus.

INTERVENTION

The patient underwent endovascular sacrifice of the involved carotid artery and radical resection of the cranial base, including exenteration of the cavernous sinus. Reconstruction with a local muscle flap was performed. He continued to receive intravenous and intrathecal administration of antibiotics.

CONCLUSION

Long-term survival with invasive rhinocerebral mucormycosis is rare, but possible, with aggressive multimodality treatment, including carotid sacrifice for en bloc resection of the pathology, when indicated.

Late angiographic follow-up review of surgically treated aneurysms

OBJECT

This study was undertaken to evaluate the long-term angiographic outcome of surgically treated aneurysms, which is unknown. Specifically, the incidence of recurrent aneurysms, the fate of residual necks, and the de novo formation of aneurysms were evaluated.

METHODS

One hundred two patients (80 females and 22 males; mean age 49 years; range 12-78 years) harboring a total of 167 aneurysms underwent late follow-up angiography; 160 aneurysms were surgically treated. Late angiographic follow-up review was obtained at a mean of 4.4 +/- 1.6 years postsurgery (range 2.6-9.7 years). Late follow-up angiography revealed two recurrent aneurysms (1.5%) of 135 clipped aneurysms without residua. Of 12 aneurysms with known residua, there were eight "dog-ear" residua, of which two (25%) enlarged. One hemorrhage was noted, yielding a hemorrhage risk of 1.9% per year. A second subgroup with broad-based residua revealed dramatic regrowth in three of four cases. Eight de novo aneurysms were found in six patients, for an annual risk of 1.8% per year. A history of multiple aneurysms was associated with de novo aneurysm formation (p = 0.049, chi-square analysis).

CONCLUSIONS

This study confirms the long-term efficacy of aneurysm clip ligation. In addition, the authors found there is a small but significant risk of de novo aneurysm formation, particularly in patients with multiple aneurysms. Most residual aneurysm rests appear to remain stable, although a subset may enlarge or rupture. These findings support the rationale for late angiographic follow-up review in patients with aneurysms.

Patients with spinal cord cavernous malformations are at an increased risk for multiple neuraxis cavernous malformations

OBJECTIVE

To determine the prevalence of multiple neuraxis cavernous malformations in patients who initially presented with intramedullary spinal cord (IMSC) cavernous malformations without knowledge of cavernous malformations elsewhere in the neuraxis.

METHODS

Hospital records and radiographic files were analyzed for 17 patients who subsequently underwent surgical resection of an IMSC cavernous malformation (histologically proven) and also underwent brain magnetic resonance imaging studies. These 17 patients represented a subset of 32 patients who underwent surgical resection of an IMSC cavernous malformation during the same period.

RESULTS

Of 17 patients, 8 (47%) harbored multiple cavernous malformations. This group was composed of five women and three men (mean age, 35.9 yr). There were four Caucasian and four Hispanic patients.

CONCLUSION

The prevalence of multiple cavernous malformations in the neuraxis seems to be increased in patients who harbor IMSC cavernous malformations. This finding has important implications for the evaluation and management of these patients and, in some cases, their family members.

Sporadic unifocal infantile myofibromatosis involving the skull. Case report

Infantile myofibromatosis involving the skull is a benign disease if there is a solitary lesion. However, the multifocal form with skull involvement may portend a lethal course in the 1st year of life if there is involvement of the heart, lungs, or gastrointestinal tract. The authors report the case of a 3-year-old boy with an enlarging left parietal skull lesion that had been present since infancy. Increasing pain and the need to obtain tissue for diagnosis led to resection of the lesion by means of a small craniectomy. Further evaluation revealed no other lesions. A distinctly rare disease is presented, and the need for staging in children younger than 2 years of age is suggested to rule out cardiac, pulmonary, or gastrointestinal involvement.

Surgical strategies for giant intracranial aneurysms

Untreated giant intracranial aneurysms have a dismal natural history as a result of hemorrhage, cerebral compression, and thromboembolism. The poor prognosis of patients with giant aneurysms therefore warrants aggressive treatment. A surgical approach is chosen to maximize the operative exposure of the aneurysm and depends mainly on the aneurysm's location. Once exposed, vascular control of the aneurysm is required not only to manage an intraoperative rupture, but also to collapse the aneurysm, to increase working space, and to improve visualization of the anatomy. Hypothermic circulatory arrest may be indicated in select patients with complex posterior circulation aneurysms. Direct clipping of giant aneurysms, with meticulous preservation of parent and branch arteries, is the preferred method of occlusion. Unclippable aneurysms require alternative techniques (e.g., trapping, parent artery occlusion, excision, and aneurysmorrhaphy) that compromise parent arteries and may require revascularization to restore adequate cerebral blood flow. Giant aneurysms are complex lesions that demand thorough surgical planning, individualized strategies, and a multidisciplinary effort in specialized neurovascular centers.

Bilateral sagittal split mandibular osteotomies as an adjunct to the transoral approach to the anterior craniovertebral junction. Technical note

Transoral approaches are used to expose the craniovertebral junction anteriorly. In patients in whom there is limited mandibular excursion, the placement of retractors and/or surgical instruments is difficult, and midline "stairstep split mandibulotomy" has been advocated as an adjunctive procedure. Although effective, this approach requires external splitting of the lip as well as median glossotomy or a lateral mucosal incision. The purpose of this study was to show that bilateral sagittal split mandibular osteotomies (BSSMOs), which are used in orthognathic surgery, represent a safer and more effective alternative to the stairstep split mandibulotomy when performed as an adjunct to the transoral approach because all incisions are intraoral and the plane of retraction is rostrocaudal instead of lateral. Hospital records and radiographic files of four patients who underwent BSSMO/transoral approach for odontoidectomy between 1994 and 1997 were reviewed retrospectively. There were three women and one boy (mean age 37.8 years, range 11-68 years). Predisposing conditions included rheumatoid arthritis (two patients), Klippel-Feil syndrome (one patient), and congenital occipitocervical instability (one patient). Jaw mobility was limited in all patients. In addition, one patient had macroglossia, another micrognathia, and another retrognathia. The BSSMO provided excellent exposure for resection of the odontoid process, as verified on follow-up magnetic resonance imaging or computerized tomography studies obtained in all patients. All mandibles were rigidly fixed by placing anterior mandibular border titanium plates and unicortical screws, and there was no incidence of nonunion or of lingual or inferior alveolar nerve injuries. The mean follow-up period was 26 months. The BSSMO is an excellent, less invasive adjunct to the transoral approach in patients with limited jaw mobility.

Subdural hematoma from a Type I spinal arteriovenous malformation. Case report

The authors report a patient in whom a subdural hematoma developed from a Type I spinal arteriovenous malformation (AVM). The patient became symptomatic with back pain, and magnetic resonance imaging revealed a spinal subdural hematoma. Selective spinal angiography, however, failed to demonstrate a pathological process. The patient underwent exploratory laminoplasty that revealed a subdural extraarachnoid hematoma with an underlying Type I spinal AVM, which was surgically obliterated. The patient recovered completely. Subdural hematomas that affect the spine are rare. Although a negative result was obtained using selective spinal angiography, exploratory surgery should be considered for the evacuation of a subdural hematoma and possibly for the definitive treatment of a spinal AVM.