Preoperative embolization of intracranial meningiomas: efficacy, technical considerations, and complications

BACKGROUND AND PURPOSE

Preoperative embolization for intracranial meningiomas offers potential advantages for safer and more effective surgery. However, this treatment strategy has not been examined in a large comparative series. The purpose of this study was to review our experience using preoperative embolization to understand the efficacy, technical considerations and complications of this technique.

MATERIALS AND METHODS

We performed a retrospective review of patients undergoing intracranial meningioma resection at our institution (March 2001 to December 2012). Comparisons were made between embolized and nonembolized patients, including patient and tumor characteristics, embolization method, operative blood loss, complications, and extent of resection. Logistic regression analyses were used to identify factors predictive of operative blood loss and extent of resection.

RESULTS

Preoperatively, 224 patients were referred for embolization, of which 177 received embolization. No complications were seen in 97.1%. There were no significant differences in operative duration, extent of resection, or complications. Estimated blood loss was higher in the embolized group (410 versus 315 mL, P=.0074), but history of embolization was not a predictor of blood loss in multivariate analysis. Independent predictors of blood loss included decreasing degree of tumor embolization (P=.037), skull base location (P=.005), and male sex (P=.034). Embolization was not an independent predictor of gross total resection.

CONCLUSIONS

Preoperative embolization is a safe option for selected meningiomas. In our series, embolization did not alter the operative duration, complications, or degree of resection, but the degree of embolization was an independent predictor of decreased operative blood loss.

Supratentorial dural-based hemangioblastoma not associated with von Hippel Lindau complex

Hemangioblastomas are rarely found in a supratentorial location and are commonly associated with the von Hippel-Lindau complex. Therefore, patients with such tumors must be evaluated for both other hemangioblastomas within the central nervous system as well as for this complex via physical examination, radiographic examination, and genetic testing. We report the seventh case of a patient with an isolated supratentorial dural based hemangioblastoma not associated with the von Hippel-Lindau complex.

The management of non-functioning pituitary adenomas

Non-functioning pituitary adenomas most commonly present secondary to mass effect and are classified according to their size and immunohistochemical staining. Local intrasellar mass effect may cause varying degrees of hypopituitarism. With extrasellar growth, neurological signs and symptoms develop. Appropriate therapy for these tumors requires close interaction across multiple disciplines. Trans-sphenoidal surgery offers safe and effective treatment in the overwhelming majority of patients with relatively low risk of new neurological and endocrinologic deficits. The multidisciplinary management of non-functioning adenomas, their diagnosis and therapeutic outcomes, is discussed.

Surgical management of pituitary adenomas

Pituitary adenomas are a diverse group of benign neoplasms. The hormonally active tumours present with well-recognised syndromes and include acromegaly (growth hormone adenoma), Cushing's disease (corticotropin adenoma), and amenorrhea-galactorrhea (prolactin adenoma or prolactinomas). The hormonally inactive, or clinically non-secreting, adenomas generally come to clinical attention secondary to local mass effect or pituitary deficiency. With the exception of the prolactinomas, transsphenoidal surgery remains the first-line therapy for most pituitary adenomas. The current diagnosis and surgical management of pituitary adenomas is discussed.

Trilateral retinoblastoma variant indicative of the relevance of the retinoblastoma tumor-suppressor pathway to medulloblastomas in humans

Results of recent studies have led investigators to suggest that the retinoblastoma tumor-suppressor (rb) gene plays an underappreciated role in the genesis of brain tumors. Such tumors cause significant rates of mortality in children suffering from hereditary retinoblastoma. It has been assumed that the pineal gland, which is ontogenetically related to the retina, accounts for the intracranial origin of these trilateral neoplasms. To address this issue, the authors describe an unusual trilateral retinoblastoma variant. The authors provide a detailed clinicopathological correlation by describing the case of a child with bilateral retinoblastoma who died of a medulloblastoma. The intraocular and intracranial neoplasms were characterized by performing detailed imaging, histopathological, and postmortem studies. Karyotype analysis and fluorescence in situ hybridization were used to define the chromosomal defect carried by the patient and members of her family. An insertion of the q12.3q21.3 segment of chromosome 13 into chromosome 18 at band q23 was identified in members of the patient's family. This translocation was unbalanced in the proband. The intraocular and cerebellar neoplasms were found to be separate primary neoplasms. Furthermore, the pineal gland was normal and the cerebellar neoplasm arose within the vermis as a medulloblastoma. Finally, the two neoplasms had different and characteristically identifiable cytolological and immunohistochemical profiles. The findings of the present study, taken together with those of recent molecular and transgenic studies, support the emerging concept that rb inactivation is not restricted to central nervous system regions of photoreceptor lineage and that inactivation of this tumor suppressor pathway may be relevant to the determination of etiological factors leading to medulloblastoma in humans.

Pilot study of electrical stimulation on median nerve in comatose severe brain injured patients: 3-month outcome

PRIMARY OBJECTIVE

To determine if electrical stimulation (ES) benefits (waking time, 3-month outcomes) treated coma patients.

RESEARCH DESIGN

Double blind randomized-controlled study.

METHODS AND PROCEDURES

Ten coma patients; six treatment and four controls, using the 'Respond Select' by EMPI.

EXPERIMENTAL INTERVENTIONS

Treatment group received radial nerve ES applied in 300 ms intermittent pulses at 40 Hz, 15-20m A 8 hours a day up to 14 days of coma; control group received sham stimulation.

MAIN OUTCOMES AND RESULTS

ES group emerged from coma mean 2 days earlier than controls, although this result was not statistically significant. At 3 months post-injury, there was no group difference in Glasgow Outcome Scale, although the ES group had improved function over controls as measured by the FIM/FAM (mean of 114 and 64.5, respectively, n.s.).

CONCLUSIONS

These data show an interesting trend, although statistical power was limited in this small pilot study, suggesting the need for a larger trial.

Acromegaly: historical perspectives and current therapy

Soon after the initial description of acromegaly in the late 19th century, neurosurgeons performed the first operative procedures for the disease. Transcranial procedures eventually yielded to the transsphenoidal approach. Reasonably effective medical therapy was introduced in the 1970s and pharmacological progress continues to be realized. It is now recognized that excess growth hormone is associated with significant morbidity and mortality and that biochemical remission improves outcome. Although medical and radiation treatments offer useful adjuncts, surgery provides optimal results.

Fluoroscopic frameless stereotaxy for transsphenoidal surgery

OBJECTIVE

To assess the value of frameless fluoroscopy-guided stereotactic transsphenoidal surgery using the FluoroNav Virtual Fluoroscopy System (Medtronic Sofamor Danek, Inc., Memphis, TN).

METHODS

Twenty consecutive patients undergoing transsphenoidal surgery for sellar lesions were assigned to transsphenoidal surgery with or without computer-assisted fluoroscopic image guidance using the FluoroNav system. Prospective data regarding patient age, sex, lesion characteristics, operative time, and treatment cost were obtained.

RESULTS

Although patients in the FluoroNav group were, on average, 17 years younger than the patients in the control group, more patients with recurrent adenomas were treated in the image guidance group. No other significant differences between the groups were found. FluoroNav provided accurate, continuous information regarding the anatomic midline trajectory to the sella turcica as well as anatomic structures (e.g., sella, sphenoid sinus) in the lateral view. No patient required reversion to intraoperative videofluoroscopy. No statistically significant differences were found with regard to preincision setup time, operative time, or cost. FluoroNav allowed procedures to be performed with significantly fewer x-rays being taken.

CONCLUSION

Fluoroscopic computer-assisted frameless stereotaxy furnishes accurate real-time information with regard to midline structures and operative trajectory. Although it is useful in first-time transseptal transsphenoidal surgery, its primary benefit is realized in recurrent surgery.

Cranioorbital fibrous dysplasia: with emphasis on visual impairment and current surgical management

Fibrous dysplasia is a benign but slowly progressive disorder of bone in which normal cancellous bone is replaced by immature woven bone and fibrous tissue. Significant deformity and both acute and chronic visual impairment can result. A contemporary understanding of fibrous dysplasia, emphasizing the origins of visual impairment, indications for decompressive surgery, and the techniques for correction of the cosmetic deformity are presented. In their experience and review of the literature, the authors found the most frequent clinical presentations to be exophthalmos, displacement of the globe, abnormalities of extraocular motility, cosmetic deformity, and visual impairment. Although traditionally the cause of visual impairment has been ascribed to impingement of the optic canal on the optic nerve, the authors' experience is that the most common cause of visual loss is cystic degeneration of the tumor, particularly with those involving the anterior clinoid process. Exophthalmos and optic canal stenosis are less common causes of visual impairment. Indications for surgical intervention include acute and/or serially radiographically documented and relentless visual impairment and significant cosmetic deformity. Individualized management strategies are also discussed.

Meningiomas of the orbit: contemporary considerations

Meningiomas are the most frequently occurring benign intracranial neoplasms. Compared with other intracranial neoplasms they grow slowly, and they are potentially amenable to a complete surgical cure. They cause neurological compromise by direct compression of adjacent neural structures. Orbital meningiomas are interesting because of their location. They can compress the optic nerve, the intraorbital contents, the contents of the superior orbital fissure, the cavernous sinus, and frontal and temporal lobes. Because of its proximity to eloquent neurological structures, this lesion often poses a formidable operative challenge. Recent advances in techniques such as preoperative embolization and new modifications to surgical approaches allow surgeons to achieve their surgery-related goals and ultimately optimum patient outcome. Preoperative embolization may be effective in reducing intraoperative blood loss and in improving intraoperative visualization of the tumor by reducing the amount of blood obscuring the field and allowing unhurried microdissection. Advances in surgical techniques allow the surgeon to gain unfettered exposure of the tumor while minimizing the manipulation of neural structures. Recent advances in technology—namely, frameless computer-assisted image guidance—assist the surgeon in the safe resection of these tumors. Image guidance is particularly useful when resecting the osseous portion of the tumor because the tissue does not shift with respect to the calibration frame. The authors discuss their experience and review the contemporary literature concerning meningiomas of the orbit and the care of patients harboring such lesions.

Bone graft substitutes for the promotion of spinal arthrodesis

In the prototypical method for inducing spinal fusion, autologous bone graft is harvested from the iliac crest or local bone removed during the spinal decompression. Although autologous bone remains the "gold standard" for stimulating bone repair and regeneration, modern molecular biology and bioengineering techniques have produced unique materials that have potent osteogenic activities. Recombinant human osteogenic growth factors, such as bone morphogenetic proteins, transforming growth factor-beta, and platelet-derived growth factor are now produced in highly concentrated and pure forms and have been shown to be extremely potent bone-inducing agents when delivered in vivo in rats, dogs, primates, and humans. The delivery of pluripotent mesenchymal stem cells (MSCs) to regions requiring bone formation is also compelling, and it has been shown to be successful in inducing osteogenesis in numerous preclinical studies in rats and dogs. Finally, the identification of biological and non-biological scaffolding materials is a crucial component of future bone graft substitutes, not only as a delivery vehicle for bone growth factors and MSCs but also as an osteoconductive matrix to stimulate bone deposition directly. In this paper, the currently available bone graft substitutes will be reviewed and the authors will discuss the novel therapeutic approaches that are currently being developed for use in the clinical setting.

Gene-based therapies for the induction of spinal fusion

Numerous mesenchymal growth factors with osteogenic properties have now been identified. Although many of these proteins can induce bone formation when delivered on a carrier matrix, these approaches have not been fully developed in the laboratory or clinic. The expression of osteogenic proteins via direct or ex vivo gene therapy techniques is also compelling because high-level, long-term gene expression can now be achieved using novel viral and nonviral vectors. In this brief review the authors will highlight recent advances in genetic therapies for the induction of osteogenesis, as well as their potential use for the promotion of spinal arthrodesis.

Acquired lumbar spinal stenosis

Based on the individual clinical presentation and radiographic findings, an operation that completely decompresses the neural elements in the spinal canal and neural foramina followed by posterior, posterolateral, or interbody fusion, with or without instrumentation should be the procedure of choice in the future. The introduction of pharmacological agents to decrease scarring around the decompressed nerve roots will also increase the number of successful procedures. It must be stressed, however, that any new operative technique must be tested in a rigorous fashion, ideally with a prospective randomized clinical trial.

Degenerative lumbar stenosis: the neurosurgical perspective

Degenerative lumbar stenosis is a complex entity caused by predictable patterns of degenerative pathoanatomy. Patients with spinal stenosis are treated by orthopaedic surgeons and neurosurgeons, who often have slightly different ideas regarding treatment strategies. However, data exist to support several recommendations, regarding fusion with or without instrumentation, surgical versus conservative treatment, and limitation of procedures to symptomatic levels. In the current study, the typical patterns of degenerative disease and surgical treatment and a view of the neurosurgical perspective of the treatment of patients with lumbar stenosis are presented.

Occipital bone graft for atlantoaxial fusion

BACKGROUND

Instability of the atlantoaxial segment is frequently encountered in neurosurgical practice. Numerous fusion techniques have been employed at this level. Most commonly, arthrodesis is achieved through bone and wire techniques. We have employed the use of suboccipital bone in lieu of iliac crest autograft in order to avoid the significant morbidity associated with iliac crest graft harvest.

METHODS

Twenty one patients suffering instability from various etiologies underwent C1-C2 fusion at our institution using occipital bone graft and wire fixation. A small craniectomy was performed near the foramen magnum, and the bone graft was notched and secured in place using wire fixation. Patients were placed in a Philadelphia or Aspen collar for 6-12 weeks postoperatively, and flexion/extension plain film of the cervical spine were used to evaluate fusion.

RESULTS

Long term follow up was available on all patients (mean 32 months, range 12-48 months). Fusion was achieved in 81% of patients within 12 weeks. Specifically, 71% (5/7) of rheumatoid patients were successfully fused. All patients with traumatic C1-C2 instability were fused. No complications were associated with the harvest of the occipital bone.

CONCLUSION

The results of fusion via this technique are comparable to other reported series of C1-C2 fusion. Additionally, the complications associated with iliac crest graft harvest were avoided by the use of occipital bone graft. Occipital bone appears to be a suitable bone graft substance for fusion of the C1-C2 level.

Chemotherapy for esthesioneuroblastomas

Esthesioneuroblastoma can be regarded as a chemosensitive tumor based on multiple reports of response to treatment. Neoadjuvant therapy is seldom curative, however, and may be of no benefit in some patients. Individuals who respond to preoperative therapy have a greater chance of long-term disease-free survival. Platinum-based therapy has been the mainstay of treatment. Toxicity has been mild, and treatment failures have been treated with postoperative chemotherapy with or without bone marrow transplantation. Given the small number of cases of esthesioneuroblastoma diagnosed annually, it is unlikely that any consensus on this issue is forthcoming. Either post- or presurgical treatment of advanced stage or recurrent disease has become the standard of care, however.

Gene therapy for skull base tumors

During the last 10 years, gene therapy has certainly risen to the forefront of basic science and clinical medicine. Designing more efficient gene delivery systems is currently the "holy grail" of genetic therapeutics, because even the most efficient viral vectors do not transfect all cells at the treatment site, which leads to local recurrence in the case of most brain tumors. The use of oncolytic viruses that propagate through tumors may have the best potential for treating skull base lesions in the future. Because many skull base tumors are histologically benign, gene therapy approaches for these tumors may be an excellent first step, as partial killing leading to local control with minimal morbidity and mortality may soon be possible. The accessibility of these tumors by endovascular approaches is also currently feasible, which could lead to high vector concentrations within the tumor bed, although limiting vector administration and gene expression in the adjacent brain. With advances in vector development, limiting gene expression to tumor cells with transcriptional or transductional targeting, and the application of more toxic gene therapy paradigms, the treatment of many skull base tumors may soon be possible.

Surgical approach to posterior skull deformity

The incidence of occipital skull flattening in infants has recently increased, partly as a result of widespread supine positioning to prevent sudden infant death syndrome. The authors discuss the causes and differential diagnosis of posterior skull deformity in this subpopulation of patients and describe their technique for surgical correction of the condition.

Sagittal synostosis

Sagittal synostosis causes predictable malformations depending on the specific suture location that fuses. Anterior fusion causes frontal bossing, whereas posterior fusion causes an occipital knob. Complete sagittal synostosis results in deformity both anteriorly and posteriorly. Variants of each type exist and therefore surgical correction must be tailored to the individual patient. Examples of the different forms of sagittal synotsosis are discussed, and the various surgical techniques available are detailed.

Resolution of tonsillar herniation and syringomyelia after supratentorial tumor resection: case report and review of the literature

OBJECTIVE AND IMPORTANCE

The pathophysiological features of syringomyelia are not yet entirely understood. We present a case of a supratentorial mass causing tonsillar herniation and syringomyelia.

CLINICAL PRESENTATION

A 51-year-old woman underwent magnetic resonance imaging for evaluation of progressive headaches. A large parieto-occipital mass was revealed. Herniation of the cerebellar tonsils and a cervical syrinx were also noted.

INTERVENTION

A craniotomy was performed without incident. After tumor resection, the tonsils ascended and the syrinx resolved in a 1-year period.

CONCLUSION

This case highlights the importance of tonsillar herniation in the pathogenesis of syringomyelia. "Acquired" Chiari malformations and syringomyelia attributable to supratentorial masses may be treated by mass resection alone, without the need for foramen magnum decompression.

The use of bone morphogenetic protein gene therapy in craniofacial bone repair

Bone morphogenetic proteins (BMPs) are capable of inducing endochondral bone formation when applied on biologic carriers in numerous mammalian in vivo assay systems. Bone morphogenetic protein gene therapy is also currently being developed to promote osteogenesis for clinical indications such as spinal fusions, craniofacial bone loss, and osteoporosis. In this study, critical-sized mandibular defects were treated with a control adenoviral vector (Ad-beta-gal), a BMP-2 adenoviral vector (Ad-BMP-2), or a BMP-9 adenoviral vector (Ad-BMP-9). Gross tissue examination, radiographic analysis, and histologic analysis demonstrated significant bony healing in the BMP treated groups compared to controls. Osteogenesis was limited to the bony defect, without extension into the surrounding soft tissues. The study suggests that with further development, BMP gene therapy may be potentially useful for repair of bony defects in the craniofacial region.

Mechanisms of premature closure of cranial sutures

Craniosynostosis is defined as premature closure of the sutures of the skull, resulting in cranial deformity. Since Virchow's original paper describing the relationship between premature suture closure and skull morphology, we have learned much about the underlying mechanisms and consequences of premature suture closure. In this paper we will describe the biology of suture closure, the rules governing the resulting phenotypes seen clinically, and a prospective study of skull growth during the 1st year of life.

Right median nerve electrical stimulation to hasten awakening from coma

Electrical stimulation of the right median nerve may hasten the awakening of closed head injured, comatose patients. A series of 25 comatose patients have been treated. These patients made better recoveries than similar individuals reported in the literature. In a double-blind pilot project patients in the treated group scored better on interval Glasgow Coma Scale scores, spent fewer days in the intensive care unit, and showed better Glasgow Outcome Scores at 1 month post-injury. Peripheral electrical stimulation of the right median nerve, through activation of the ascending reticular activating system, may be sufficient to arouse the moderate to severely comatose patient.

Solitary sarcoid granuloma of the cerebellopontine angle: a case report

BACKGROUND

Sarcoidosis involves the nervous system about 5% of the time and usually manifests as a granulomatous inflammation of the basal meninges and hypothalamus. Cases which are strictly isolated to the central nervous system occur infrequently; rarely, they may present as an intracranial mass.

METHODS

We present the case of a solitary sarcoid granuloma at the cerebellopontine angle in a 42-year-old female who presented with headache, facial numbness, and hearing loss.

RESULTS

A suboccipital craniectomy was performed and the lesion was noted to be grossly adherent to the lower cranial nerves and skull base. The lesion was misdiagnosed as a meningioma with preoperative magnetic resonance imaging and intraoperative histology, and perhaps additional morbidity resulted.

CONCLUSION

We present this case in order to demonstrate the importance of differentiating these dural-based lesions and propose that cases of neurosarcoidosis presenting as a solitary granuloma be treated with surgical debulking and immunosuppression.

CT-guided percutaneous drainage of syringomyelia

PURPOSE

Our purpose is to describe CT-guided percutaneous drainage of syringomyelia as a possible contribution in patient management.

METHOD

CT-guided percutaneous drainage was performed on three patients with symptomatic syringomyelia. We determined the success of percutaneous decompression by subsequent CT and MRI. The effect of syringomyelia decompression in relation to the patient's symptoms was determined. This information was then used to help guide clinical management.

RESULTS

In Case 1, percutaneous drainage of a large syrinx in a C5 quadriplegic patient with increasing lower extremity spasticity demonstrated significant decompression by imaging but did not result in clinical improvement. A surgical procedure to decompress the syrinx was not performed on the basis of this information. In Case 2, percutaneous drainage of a large syrinx in a quadriplegic patient with increasing upper extremity numbness and weakness demonstrated significant decompression by imaging and resulted in sustained clinical improvement, temporarily obviating the need for surgery. In Case 3, percutaneous drainage of the rostral aspect of a septated syrinx cavity in a patient with a Chiari I malformation and a syringoperitoneal shunt in place resulted in decompression by imaging but failed to relieve the patient's newly developed symptoms. An additional shunt was therefore not placed. In no case did the patient experience periprocedural complications or worsening of symptoms.

CONCLUSION

CT-guided percutaneous drainage of syringomyelia is a safe and successful technique. It can be used diagnostically to identify patients that may or may not benefit from surgical syrinx decompression and in some cases may provide a temporary therapeutic alternative to surgery.

Use of preoperative computed tomography-angiography in cranial remodeling: technical note

OBJECTIVE/IMPORTANCE: One of the most severe complications of craniosynostosis repair is dural sinus laceration. Massive hemorrhage and air embolism are potentially life-threatening sequelae that can result from such an event. The aberrant anatomy of patients with craniosynostosis only accentuates this risk, because separation of the calvaria from the underlying dura is often performed without direct visualization of the sinuses.

METHODS

Three-dimensional computed tomography was combined with computed tomographic angiography in the preoperative assessment of patients with craniofacial abnormalities.

RESULTS

A clear understanding of the dural sinus anatomy in relation to the overlying bony landmarks became available to the operating surgeon. Six patients underwent this procedure, with excellent visualization of the bony and sinus anatomy achieved in all cases.

CONCLUSION

It is thought, that the benefit of combining these procedures has been significant by allowing the visualization of the dural sinus anatomy and overlying bony landmarks. This procedure conveys minimal concomitant morbidity or expense to the patient, yet offers valuable insight toward operative planning and complication avoidance.

Neurosurgery at the University of Virginia

Before 1937, members of the Department of Surgery and Gynecology practiced emergency neurosurgery at the University of Virginia in the same fashion as in other hospitals in the United States. In 1937, Claude C. Coleman, Chairman of the Department of Neurosurgery at the Medical College of Virginia in Richmond, organized a Division of Neurosurgery as part of the Department of Surgery and Gynecology at the University of Virginia. He designated one of his staff members, John M. Meredith, as Neurosurgeon-in-charge. Dr. Coleman served as Clinical Professor of Neurological Surgery at the University of Virginia from 1937 to 1941, while also working in Richmond. This arrangement attracted increasing numbers of patients, leading to the formation of a separate department, under the direction of William Gayle Crutchfield, in 1941. In conjunction with Juan de Dios Martinez-Galindo, who joined the faculty in 1943, Dr. Crutchfield built and directed the neurosurgical training program until his retirement. In 1969, John A. Jane, Sr., became Professor and Chairman of the Department of Neurosurgery. Pursuing the Jeffersonian intent of attracting "... those of due degree of science and of talents for instruction," the Department has been enhanced by the arrival of Neal F. Kassell in 1984, Ladislau Steiner in 1987, Edward R. Laws, Jr., in 1992, Dheerendra Prasad in 1995, Gregory Helm in 1996, and Mark Shaffrey in 1997. Resident training has been a priority of the Department of Neurosurgery; many academic neurosurgeons were trained and practiced their specialty in the Department early in their careers. Sixty years after its foundation, the Department of Neurosurgery continues its commitment to patient care, research, and the "... instruction of those who come after us."

The role of preoperative adjuvant treatment in the management of esthesioneuroblastoma: the University of Virginia experience

OBJECTIVE

Multidisciplinary management of esthesioneuroblastoma has effected markedly increased survival during the past 20 years. The potential for radical craniofacial surgery for complete en bloc resection, the availability of advanced neuroimaging modalities, and the incorporation of neoadjuvant therapy into treatment strategies for tumor remission have all contributed to this accomplishment. However, a standard protocol for the management of these lesions has not been accepted; preoperative radiation and chemotherapy have been advocated, but neither radiographic nor clinical response has been quantified.

METHODS

Thirty-four consecutive patients with biopsy-proven esthesioneuroblastoma treated at one institution from 1976 to 1994 were reviewed to determine the effects of preoperative radiation therapy, with or without chemotherapy, on tumor size and long-term survival.

RESULTS

In a multivariate regression analysis, advanced age was predictive of decreased disease-free survival (P=0.008), whereas advanced Kadish stage was associated with a borderline higher rate of disease-related mortality (P=0.056). Two-thirds of the patients showed a significant reduction in tumor burden with adjuvant therapy. Patients with response to neoadjuvant therapy demonstrated a significantly lower rate of disease-related mortality (P=0.050). In this series, the overall 5- and 10-year survival rates were 81.0 and 54.5%, respectively.

CONCLUSION

Preoperative neoadjuvant therapy provides a valuable complement to radical craniofacial resection, leading to reduction in tumor burden. Patients experiencing reduction in tumor volume by neoadjuvant therapy demonstrate an improved prognosis.

Intraoperative chymopapain in lumbar laminotomy for disc disease: a less invasive technique

The use of chymopapain in the treatment of lumbar disc herniation has been widely studied since Smith first described its use in humans in 1963. The authors describe the use of chymopapain intraoperatively in open lumbar microdiscectomy in 63 patients. When combined with the results of a previous study performed at the same institution, the authors found that this technique significantly reduces the rate of recurrent disc herniation when compared with traditional laminotomy with discectomy. This procedure maximizes the benefits of each approach taken separately, allowing for decompression of the nerve root from a free fragment or sequestered disc and preventing recurrence through dissolution of the nucleus pulposus. Overall, outcome was good or excellent immediately postoperatively in 73% of the 63 patients and in 64% at last follow-up evaluation. Additionally, this procedure is safe with no complications noted in the immediate perioperative period or at follow-up evaluation.

Successful excision of a large immature teratoma involving the cranial base: report of a case with long-term follow-up

OBJECTIVE AND IMPORTANCE

Massive congenital intracranial teratomas with extracranial extension are rare. The prognosis in these cases has been poor, with stillbirth or immediate postpartum death as the usual outcome. With recent advances in fetal monitoring, neonatal care, and surgical techniques used for the management of complex tumors of the cranial base, some of these lesions may now be amenable to radical surgical resection and then immediate craniofacial reconstruction.

CLINICAL PRESENTATION

A neonate with a large congenital immature teratoma involving the entire left side of the cranium and face was evaluated at our institution 1 day after birth.

INTERVENTION

Total resection of the mass and then immediate reconstruction of the deformed orbit, maxilla, and mandible were performed at 9 days of age. Additional operations on the midface and mandible to allow for a functional bite were subsequently required as the child developed during the next 2 years. Four years after resection, the patient exhibited a reasonable cosmetic result and only mild developmental delay.

CONCLUSION

We conclude that acceptable functional and cosmetic outcomes can be achieved by early intervention, consisting of radical resection and immediate craniofacial reconstruction, in some neonates with massive congenital craniofacial teratomas.

Correction of posterior sagittal craniosynostosis

Craniosynostosis involving the posterior sagittal suture results in a characteristic skull deformity known as bathrocephaly. Surgical correction of this deformity using the reverse pi procedure has yielded inconsistent results. We present a new method for expanding the transverse posterior skull while simultaneously reducing the longitudinal dimension. An absorbable microplate-reinforced bone strut is used as a framework on which the remainder of the skull is reconfigured; its stability prevents relapse. The posterior skull squeeze is produced using absorbable mesh plates. Use of rigid fixation is limited to absorbable hardware in the growing craniofacial skeleton.

Pitfalls and successes of peer review in neurosurgery

As the first editor of the Journal of Neurosurgery, Louise Eisenhardt, acting with the advice of the editorial board, was responsible for making decisions on the acceptance or rejection of submitted manuscripts. Her log, covering the first 14 years of editorial decisions, is a record of neurosurgical progress and of the forces--scientific, technical and other--that shaped the field of neurosurgery. Any peer-review process is subject to pitfalls that become evident in retrospect, but an effective peer-review process is one of the basic ingredients of scientific progress. The decisions to accept or reject manuscripts submitted to the Journal of Neurosurgery during Eisenhardt's tenure are highlighted in this historical vignette.

Hemorrhagic complications in embolization of a meningioma: case report and review of the literature

We report a case of hemorrhage in a parasellar meningioma shortly after embolization of the dural cavernous carotid artery branches supplying the tumor. This represents the first report of hemorrhage within a meningioma resulting from embolization with small (50 to 150-microns) polyvinyl alcohol particles, as well as the first reported case of hemorrhage complicating meningioma embolization from internal rather than external carotid artery branch embolization. We also review previously reported cases of postembolization hemorrhage from meningiomas.

Acquired lumbar stenosis: topic review and a case series

Stenosis of the central and lateral lumbar vertebral canal can be congenital or acquired; the latter is most often caused by a degenerative process. The associated neurogenic claudication and/or radiculopathic symptom complexes are thought to result from compression of the cauda equina and lumbosacral nerve roots by hypertrophy of or encroachment by any combination of the following: canal walls, ligamenta flava, intervertebral discs, posterior longitudinal ligament, or epidural fat. The authors' technique for the treatment of lumbar stenosis involves extensive unilateral decompression with undercutting of the spinous process and obviates the need for instrumentation by using a contralateral autologous bone fusion. The results in a series of 29 patients in whom the procedure was performed suggest that this decompression method safely and successfully treats not only the radicular symptoms caused by lateral stenosis but also the neurogenic claudication symptoms associated with central stenosis. In addition, the procedure can preserve spinal stability without instrumentation by using contralateral autologous bone fusion along the laminae and spinous processes.

Recovery of useful hearing after posterior fossa surgery: the role of otoacoustic emissions: case report

OBJECTIVE AND IMPORTANCE

Hearing preservation has become an important issue in surgical procedures involving the cerebellopontine angle (CPA). Although several prognostic factors for hearing preservation in patients with "useful" preoperative hearing have been described, it is difficult to predict which patients have the potential for hearing preservation or recovery. Otoacoustic emission measurement is a new technique that allows recording of sounds produced by the cochlear outer hair cells as a normal byproduct of the receptor process and can be used to assess cochlear involvement in patients with hearing loss.

CLINICAL PRESENTATION

We present the case of a 53-year-old patient with a recurrent arachnoid cyst of the CPA. She had noticed progressive severe hearing loss ipsilateral to the cyst that was confirmed by preoperative audiogram.

TECHNIQUE

Otoacoustic emissions were obtained and were within normal limits on the involved side, suggesting that the cochlear outer hair cells were still intact and that the patient had the potential for hearing recovery. The CPA was decompressed by marsupialization of the cyst. Postoperative audiogram demonstrated a dramatic recovery of hearing to a normal level.

CONCLUSION

Otoacoustic emissions clearly provide valuable information about the potential for hearing preservation/recovery after CPA surgery and have significant implications for the current neurosurgical management of these lesions.

Partial pediculectomy in the treatment of lumbar spinal stenosis: technical note

OBJECTIVE

We note an additional pathological condition associated with lumbar spinal stenosis that may be responsible for significant postoperative pain. Recognizing that nerve roots are stretched around hypertrophic pedicles in some cases of spinal stenosis, we have altered our surgical management of these cases to address what may be a previously unrecognized but significant anatomic pathological finding.

SURGICAL TECHNIQUE

After ipsilateral posterior bony decompression of the spinal canal, the nerve root is examined as it courses around the pedicle. If the root appears stretched, the medial part of the pedicle is removed using first a diamond bit and then a curet. The nerve root is retracted and protected during this procedure.

RESULTS

Inspection of the root after partial pediculectomy frequently reveals lateral movement of the root into space previously occupied by the pedicle. Anatomically, the nerve is better decompressed and free of obstruction. This technique adds little time to the overall duration of the operation.

CONCLUSION

Anatomic evidence obtained through intraoperative examination and preoperative imaging techniques indicates that partial pediculectomy may play a role in the treatment of some cases of lumbar stenosis.

Decompressive bifrontal craniectomy in the treatment of severe refractory posttraumatic cerebral edema

OBJECTIVE

The management of malignant posttraumatic cerebral edema remains a frustrating endeavor for the neurosurgeon and the intensivist. Mortality and morbidity rates remain high despite refinements in medical and pharmacological means of controlling elevated intracranial pressure; therefore, a comparison of medical management versus decompressive craniectomy in the management of malignant posttraumatic cerebral edema was undertaken.

METHODS

At the University of Virginia Health Sciences Center, 35 bifrontal decompressive craniectomies were performed on patients suffering from malignant posttraumatic cerebral edema. A control population was formed of patients whose data was accrued in the Traumatic Coma Data Bank. Patients who had undergone surgery were matched with one to four control patients based on sex, age, preoperative Glasgow Coma Scale scores, and maximum preoperative intracranial pressure (ICP).

RESULTS

The overall rate of good recovery and moderate disability for the patients who underwent craniectomies was 37% (13 of 35 patients), whereas the mortality rate was 23% (8 of 35 patients). Pediatric patients had a higher rate of favorable outcome (44%, 8 of 18 patients) than did adult patients. Postoperative ICP was lower than preoperative ICP in patients who underwent decompression (P = 0.0003). Postoperative ICP was lower in patients who underwent surgery than late measurements of ICP in the matched control population. A statistically significant increased rate of favorable outcomes was seen in the patients who underwent surgery compared to the matched control patients (15.4%) (P = 0.014). All patients who exhibited sustained ICP values above 40 torr and those who underwent surgery more than 48 hours after the time of injury did poorly. Evaluation of the 20 patients who did not fit into either of those categories revealed a 60% rate of favorable outcome and a statistical advantage over control patients (P = 0.0001).

CONCLUSION

Decompressive bifrontal craniectomy provides a statistical advantage over medical treatment of intractable posttraumatic cerebral hypertension and should be considered in the management of malignant posttraumatic cerebral swelling. If the operation can be accomplished before the ICP value exceeds 40 torr for a sustained period and within 48 hours of the time of injury, the potential to influence outcome is greatest.

Elevated levels of transforming growth factors beta 2 and beta 3 in lambdoid sutures from children with persistent plagiocephaly

OBJECTIVE

To analyze the pertinent history and physical findings specific to the subset of patients with a progressive posterior skull deformity, requiring surgery to correct their deformity.

PATIENTS

Since the Academy of Pediatrics issued its recommendation on supine positioning of infants to prevent sudden infant death syndrome (SIDS) in 1992, 73 children have presented to the University of Virginia Craniofacial Anomalies Clinic with posterior-skull deformities. The majority were successfully managed with conservative therapy, but in six patients, the deformity was severe and persistent, requiring surgical correction. All six children were older (7.5-12 mo), presenting with more severe morphologic appearances and a higher incidence of associated neurodevelopmental delay. Three had family backgrounds of isolated craniosynostosis.

METHODS

Characteristics of these patients were examined to determine why they may have differed from those that responded to conservative management. Immunohistochemical staining of their lambdoid sutures was performed.

RESULTS

Significantly increased staining for TGF-beta 2 and TGF-beta 3, potent stimulators of bone cell growth and differentiation, was seen in all 'affected' sutures from the flattened side of the skull, compared to unaffected sutures from the protruding side of the skull-a pattern similar to that seen during normal bony obliteration of calvarial sutures.

CONCLUSION

The majority of patients with posterior plagiocephaly associated with positioning responded to conservative management, while a small subset of patients with persistent posterior skull deformation required surgical intervention. A genetic basis for the latter patients' persistent plagiocephaly, rather than positioning, cannot be ruled out. Genetics, prolonged external pressure against the sutures, or a combination of these factors may lead to permanently raised levels of growth factors in 'affected' sutures.

Solitary fibrous tumor of the spinal cord

We report a case of primary solitary fibrous tumor occurring in the intramedullary thoracic spinal cord in a 47-year-old man. The tumor predominately consisted of spindle cells separated by abundant collagen; a few areas of hemangiopericytomatous morphology were also present. The diagnosis was confirmed by immunohistochemistry and electron microscopy. The tumor was reactive to vimentin and CD34 but was negative for glial fibrillary acid protein (GFAP), S-100, smooth muscle actin, epithelial membrane antigen, HMB-45, myelin basic protein, and keratin; ultrastructural examination showed fairly undifferentiated cells within a collagenous matrix, few tight junctions, and sparse extravascular basement membrane. The occurrence of this tumor within the spinal cord parenchyma and in other extraserosal sites emphasizes the current belief that solitary fibrous tumors arise from mesenchymal tissues and are not restricted to the pleura and other serosal surfaces. Furthermore, solitary fibrous tumor is an entity that must be considered in the differential diagnosis of spindle cell central nervous system neoplasms.

Occipital flattening in the infant skull

Occipital plagiocephaly caused by lambdoid synostosis is rare. Positional flattening is more common and will most often respond to conservative measures. Surgical correction of a flat occiput is warranted if the deformity is profound. Skull molding devices may be effective for treating mild abnormalities but are ineffective in the more severe cases. An operative procedure is described that uses a microplate-reinforced median bar to provide a rigid scaffold to maintain the occipital correction. Seventy-three consecutive patients were evaluated over a 3-year period for occipital plagiocephaly. Of these individuals, only one had true lambdoid synostosis and six required surgery. There were no operative complications and cranial length was increased from 84 to 94% of age-matched controls after surgery. The need for operative intervention is rare; however, it should be based on the severity of the posterior deformity, especially when accompanied by compensatory frontal bossing, and not on the etiology of the flattening.

Utilization of type I collagen gel, demineralized bone matrix, and bone morphogenetic protein-2 to enhance autologous bone lumbar spinal fusion

Autologous bone grafts are currently considered "gold standard" material for achieving long-term spinal arthrodesis. The present study was performed to determine whether demineralized bone matrix (DBM), type I collagen gels, or bone morphogenetic protein-2 (BMP-2) can improve autologous bone spinal fusions. Using a unilateral decompression-contralateral fusion technique in dogs, each of these materials was added to an autologous bone graft. Volumetric analysis, histological analysis, and biomechanical testing were performed to assess the effectiveness of each material. The DBM had an inhibitory effect on solid bone fusion of the spine, whereas the type I collagen gels improved the bony interface between the graft and the host spine. The BMP-2 strongly enhanced the amount of bone deposition at the fusion site and increased the number of intervertebral levels that were solidly fused. This study strongly supports the use of BMP-2 as an additive to autologous bone grafts in spine stabilization.

Acrylic cranioplasty using miniplate struts

OBJECTIVE

Cranioplasty using acrylic is a common procedure in patients with cranial defects secondary to trauma, infection, or tumor. The limitations of this technique include poor adherence of the acrylic to surrounding bone and difficulty in achieving a proper cosmetic contour in complicated cranial defects, especially those involving the orbital rim. The authors have been continually developing techniques of cranioplasty.

METHODS

Ten consecutive cranioplasties were performed over the past 5 years using this new technique.

TECHNIQUE

The authors describe a technique using miniplates as struts to which the acrylic is applied using a "reinforced concrete" principle.

RESULTS/CONCLUSION

All patients achieved excellent cosmetic results with no complications. This technique allows contour of the repair site while the acrylic is curing and provides a more resilient resulting prosthesis.