bluuebunny/crossref_metadata_2025 huggingface dataset:
Complication avoidance in the treatment of malignant tumors of the skull base
Authors: Kryzanski James T. , Annino Donald J. , Heilman Carl B.
Published: January 2008

The treatment of malignant skull base tumors has improved with the development of skull base surgical approaches that allow en bloc resection of a lesion and increase the efficacy of adjuvant therapies. The anatomical complexity of these lesions and their surroundings has led to a relatively high complication rate. Infection and cerebrospinal fluid fistulas are the most common serious procedure-related complications. They result from the frequent necessity of working in a contaminated space such as the paranasal sinuses as well as from the creation of large dural and skull base defects. The authors have reviewed the literature regarding complications of surgery for malignant skull base lesions and present several techniques and strategies for minimizing their incidence by performing the craniofacial approach to anterior skull base lesions.
Single enhancing computerized tomography–detected lesion in immunocompetent patients
Authors: Garg Ravindra Kumar
Published: January 2008

Single enhancing computerized tomography (CT)–documented lesions may occur in several infectious and neoplastic diseases of the central nervous system and are the most common radiological abnormality seen in patients with acute-onset seizures in India and many other developing countries. Similar CT-documented lesions have also been reported in the developed world where these lesions are often considered to be caused by neoplasms or tuberculoma. Histopathological studies in India and even in some developed countries revealed that neurocysticercosis (NCC) is the most likely cause of these lesions provided they fulfill a rigid set of clinical and radiological criteria. Single cysticer-cus granuloma measures less than 20 mm in diameter, may be associated with cerebral edema not severe enough to produce midline shift, and occur in patients with seizures, normal neurological status, and no evidence of active systemic disease. When these lesions resolve spontaneously, either disappearing or changing into a calcified nodule, the diagnosis of NCC is very likely. The second most common cause of these CT-detected lesions is tuberculoma; in patients with these lesions similar clinical and neuroimaging features are also present. Few authors believe that in poor and developing countries, where both tuberculosis and NCC are common, it is difficult to differentiate between tuber-culoma and a single cysticercal granuloma. The most interesting feature of these solitary enhancing lesions is their spontaneous disappearance within weeks or months. Some lesions “heal” by becoming calcified. These patients require only antiepileptic therapy, and this medication may be withdrawn safely after the lesion has resolved on CT scanning. In several studies provision of anticysticercal drugs has been attempted, but because of conflicting results, their role in the management of these single lesions is uncertain. Neurosurgeons have a very limited role to play. In very rare situations, if the lesion increases in size and if focal neurological deficits manifest or seizures are uncontrolled, a brain biopsy sample may be required and histopathological evaluation performed to establish the correct diagnosis.
Spinal neurocysticercosis
Authors: Alsina George A. , Johnson J. Patrick , McBride Duncan Q. , Rhoten Patrick R. L. , Mehringer C. Mark , Stokes John K.
Published: January 2008

Worldwide, cysticercosis is the most common parasitic infection of the central nervous system. In endemic regions, the incidence of neurocysticercosis (NCC) approaches 4% of the general population. The disease is predominantly intracranial, the authors of most series generally report the incidence of spinal NCC as only 1.5 to 3% of all cases. Although spinal NCC is relatively rare, it represents a distinct clinical entity that can have devastating consequences for the patient. Because of the limited size of the spinal canal, the mass effect of these lesions is poorly tolerated. Most spinal NCC occurs in the subarachnoid space where mass effect can cause spinal cord compression, although obstruction of cerebrospinal fluid pathways due to scarring of the subarachnoid space can also cause symptoms.

The authors treated six patients with spinal NCC. In five cases the lesions were located in the subarachnoid space, and in one the lesion was intramedullary. All patients with subarachnoid spinal NCC required excision of the symptomatic lesions; in two cases initial medical therapy had failed. The patient with intramedullary spinal NCC experienced mild symptoms and underwent steroid therapy. All patients experienced variably improved outcomes and were eventually ambulatory.

Medical therapy should be carefully considered in selected patients in whom symptoms are stable and nonprogressive. Surgical intervention is required when severe or progressive deficits occur to prevent permanent injury. In some patients recovery may be limited as a result of inflammatory injury to the spinal cord or arachnoidal adhesions.
Leptomeningeal dissemination of pilocytic astrocytoma via hematoma in a child
Authors: Kanda Masaru , Tanaka Hidenobu , Shinoda Soji , Masuzawa Toshio
Published: January 2008

A case of recurrent pilocytic astrocytoma with leptomeningeal dissemination (LMD) is described. A cerebellar tumor was diagnosed in a 3-year-old boy, in whom resection was performed. When the boy was 6 years of age, recurrence was treated with surgery and local radiotherapy. At age 13 years, scoliosis was present, but the patient was asymptomatic. Twelve years after initial surgery LMD was demonstrated in the lumbar spinal region without recurrence of the original tumor. This tumor also was subtotally removed. During the procedure, a hematoma was observed adjacent to the tumor, but the border was clear. Histological examination of the spinal cord tumor showed features similar to those of the original tumor. There were no tumor cells in the hematoma. The MIB-1 labeling index indicated no malignant change compared with the previous samples. Radiotherapy was performed after the surgery. The importance of early diagnosis and management of scoliosis is emphasized, and the peculiar pattern of dissemination of the pilo-cytic astrocytoma and its treatment are reviewed.
Discography interpretation and techniques in the lumbar spine
Authors: Tomecek Frank J. , Anthony C. Scott , Boxell Chris , Warren Jennifer
Published: January 2008

The authors provide an indepth analysis of discography, a provocative diagnostic tool to determine the origin of low-back pain. Injecting the intervertebral disc with radiopaque dye provides physicians with several useful pieces of information. First, the modality provides radiographic evaluation of the integrity of the nucleus pulposus and anular rings to determine tears or other lesions that could be creating low-back pain. Second, and very important, is its measure of disc nociception. A normal disc should not cause pain when injected; however, a disc that is physiologically compromised can mimic the pain previously experienced by a patient. The authors review the indications, technique, and interpretation of discography to allow a better understanding of when to use this diagnostic test and what to do with the results.
Black disc disease: a commentary
Authors: Rengachary Setti S. , Balabhadra Raju S. V.
Published: January 2008

Internal disc disruption associated with axial back pain but not radicular pain is a disease entity that was recognized about two decades ago as a disorder that could potentially be treated by spinal fusion. In this article the authors describe the clinical syndrome, magnetic resonance imaging and discography findings of pathophysiological pain generation, and the available surgical options. Based on the current understanding of this disease entity, the optimum surgical procedure entails radical discectomy, anterior column support, adequate amounts of auto- or allograft bone, bone extenders and enhancers, and rigid stabilization of the motion segment.
Lumbar microdiscectomy: a historical perspective and current technical considerations
Authors: Koebbe Christopher J. , Maroon Joseph C. , Abla Adnan , El-Kadi Hikmat , Bost Jeffery
Published: January 2008

A historical review is presented of the original descriptions of lumbar discectomy, focusing on the evolution toward a less invasive surgical approach following the introduction of the operating microscope. From the initial work in Europe by Yaşargil and Caspar to the popularization of microdiscectomy by Williams and Wilson in the United States, this procedure has successfully reduced operative time, surgical morbidity, and incision size while allowing patients to return to work faster. Emphasis is placed on the importance of a careful preoperative clinical and radiographic evaluation by identifying factors that may help in the prediction of a successful surgical outcome. A modification of the lumbar microdiscectomy technique is described including patient positioning in the lateral position as well as minimal disc space and nerve root manipulation. In their experience performing more than 3000 microdiscectomies, the authors have produced good-to-excellent clinical results in nearly 90% of patients, with the majority returning to work within 1 month. The complication rate of dural tears, discitis, or root injury has been less than 2%, with a reoperation rate of 5%. The authors believe that lumbar microdiscectomy remains the gold standard with which all other discectomy techniques must be compared.
Outcome analysis of patients after ligament-sparing microdiscectomy for lumbar disc herniation
Authors: Park Youn-Kwan , Kim Joo-Han , Chung Heung-Seob
Published: January 2008

Object

The authors describe a microsurgical technique for the preservation of the ligamentum flavum and the long-term surgery-related results, including an independent assessment of outcome.

Methods

Three hundred seventy-seven patients underwent ligament-sparing microsurgical discectomy for a previously untreated single-level lumbar disc herniation and were followed for more than 2 years. A successful outcome at 6 months was demonstrated in 93.9% of the patients. At a median follow-up period of 30 months, successful patient-assessed outcome was 84.1%. During the mean follow-up period of 4.2 years (range 2–6.5 years), recurrent disc herniation was detected in 18 patients (4.8%). These patients all underwent repeated surgery. The overall surgery-related rate of complications was 1.3%.

Conclusions

The authors conclude that ligament-sparing microdiscectomy is a safe procedure, with a favorable success rate and minimal morbidity. Reoperation is safer and easier when using this technique compared with traditional ones.
Identifying patients at risk for postprocedural morbidity after treatment of incidental intracranial aneurysms: the role of aneurysm size and location
Authors: Janardhan Vallabh , Friedlander Robert , Riina Howard , Stieg Philip Edwin
Published: January 2008

Object

A decision to treat incidental intracranial aneurysms (IIAs) relies on understanding the risks of treatment and weighing them against the those of aneurysm rupture. Whereas the natural history of IIAs is currently being studied, the risks associated with treating IIAs and factors associated with poor outcome need to be clearly established.

Methods

In a consecutive series of 125 patients, 160 IIAs were treated either surgically (152 cases) or endovascularly (eight cases). Postprocedural morbidity was defined as a new neurological deficit associated with a score greater than or equal to 3 on the modified Rankin Scale or a score of less than 24 on the Mini-Mental Status Examination. Logistic regression analysis was used to identify predictors of postprocedural morbidity from retrospectively collected data on demographic, clinical, and radiographic characteristics.

Treatment of IIAs was not associated with any mortality and was associated with postprocedural morbidity in 17 (13.6%) of 125 patients (early outcome) and eight (6.4%) of patients (late outcome). In the logistic-regression model, treatment of aneurysms (≥13 mm) and posterior circulation aneurysms were independently associated with postprocedural morbidity. In patients in whom postprocedural neurological deficits developed, 12 (70.6%) of 17 and four (23.5%) of 17 patients harbored aneurysms with broad or calcified necks, respectively. Age, comorbidities, multiple aneurysms, specific aneurysm location, and history of subarachnoid hemorrhage related to a different aneurysm were not significantly associated with poor outcome.

Conclusions

The authors found that IIAs can be safely and effectively treated without causing mortality and with a lower morbidity rate than previously reported. A combination of radiographic variables may be helpful in identifying patients at risk for postprocedural morbidity.
Surgical management of unruptured basilar artery bifurcation aneurysms
Authors: Dumont Aaron S. , Oskouian Rod J. , Chow Michael M. , Kassell Neal F.
Published: January 2008

The basilar artery (BA) bifurcation is the most common site for aneurysms arising from the posterior circulation. Their inhospitable location, nested within the narrow confines of the interpeduncular fossa anterior to the brainstem, coupled with the rich network of adjacent critical thalamoperforating arteries irrigating the midbrain and thalamus, pose difficult anatomical obstacles for the surgeon.

The age old adage that the only cure for intracranial aneurysms remains exclusion from circulation before rupture still holds true. Although management of unruptured aneurysms in general is still controversial, unruptured aneurysms of the BA bifurcation can be treated surgically with acceptable rates of morbidity. The clinician must gather and weigh all clinical, pathological, and radiological data when formulating recommendations for the individual patient.

In the present report the authors describe their current technique for the surgical management of unruptured BA bifurcation aneurysms; this represents the culmination of the senior author's (N.K.) experience in the management of both ruptured and unruptured BA bifurcation aneurysms. A modified, right-sided subtemporal transtentorial approach has been adopted in all cases of isolated unruptured BA bifurcation aneurysms. Technical nuances are described.
Spinal extradural meningeal cyst: correct radiological and histopathological diagnosis
Authors: Sato Kimiaki , Nagata Kensei , Sugita Yasuo
Published: January 2008

Object

Spinal extradural meningeal cysts are uncommon and rarely cause neural compression. The clinical, radiological, and histopathological characteristics of the lesions are discussed and previous reports reviewed.

Methods

The authors describe five cases of a spinal extradural meningeal cyst (three female and two male patients, with a mean age of 47 years (range 14–75 years). Four of the cysts were located at the thoracolumbar level, the fifth at the sacral level. Radiological and neuroimaging-based diagnosis was made using a combination of magnetic resonance imaging, myelography, and/or computerized tomography (CT) myelography.

A connection between the spinal subarachnoid space and the cyst cavity was demonstrated on myelography and/or CT myelography in all cases, and dural defects were confirmed visually intraoperatively. In all cases histopathological examination confirmed that the cyst wall was formed by nonspecific fibrous connective tissue without a single-cell layer of inner arachnoid lining.

Conclusions

A diagnosis of spinal extradural meningeal cyst is difficult to make based solely on histopathological examination. It is essential that the final characterization and diagnosis be based on intraoperative inspection combined with radiological and histopathological findings.
The role of cell therapy for stroke
Authors: Kondziolka Douglas , Wechsler Lawrence , Tyler-Kabara Elizabeth , Achim Cristian
Published: January 2008

Cellular therapy has been evaluated in small animals, subhuman primates, and now humans for the potential repair of brain injury due to stroke. Experimental striate stroke models have proven useful for the purpose of evaluating different treatment paradigms. Early clinical trials involving neuronal transplantation in patients suffering motor-related stroke in the basal ganglia region have begun.

This research will be described in this report.
Glial cell line–derived neurotrophic factor–supplemented hibernation of fetal ventral mesencephalic neurons for transplantation in Parkinson disease: long-term storage
Authors: Hebb Adam O. , Hebb Kari , Ramachandran Arun C. , Mendez Ivar
Published: January 2008

Object

Investigation of fetal dopaminergic tissue transplantation is being conducted in animal models and clinical trials as a potential treatment for advanced Parkinson disease (PD). Because the availability of fetal tissue is limited, however, the duration of its storage prior to transplantation is a key practical issue. Longer storage times may enable fetal tissue obtained over several days to be pooled together for transplantation in a recipient. Glial cell line–derived neurotrophic factor (GDNF) has been shown to improve survival of stored human dopaminergic tissue prior to transplantation. The objective of this study was to evaluate GDNF-supplemented hibernation of fetal dopaminergic tissue for extended periods of 6 to 15 days.

Methods

A total of 27 rat ventral mesencephalons (VMs) were obtained in gestation Day 14 rat fetuses, and three were cultured immediately (fresh-culture control group). The remaining 24 VMs were divided sagittally along the mid-line to form 48 equal pieces of hemimesencephalons. Twenty-four pieces were stored with GDNF-supplemented hibernation medium for 6, 9, 12, or 15 days, and the 24 “partner” hemimesencephalons were stored in control hibernation medium for the same periods of time. Tissue was cultured for 48 hours and processed for tyrosine hydroxylase (TH) immunoreactivity and cresyl violet. Cell counts for all cultures and percentage of TH-immunoreactive cells were obtained. The percentage of TH-positive cells for the fresh control group was 6.3 ± 0.5%; that measured in cultures derived from tissue hibernated in GDNF-supplemented medium was significantly increased at 6 and 9 days posthiber-nation compared with the fresh-culture control group and the partner groups stored in hibernation medium only. No significant increase in percentage of TH-immunoreactive cells was observed in the 12- and 15-day hibernation groups.

Conclusions

In summary the authors found that fetal dopaminergic tissue can safely be stored up to 9 days in GDNF-supplemented hibernation medium. Furthermore the percentage of TH-immunoreactive cells is significantly increased after 6 and 9 days of storage in this medium, improving the yield of TH-positive cells prior to transplantation. These observations may have important clinical implications for collecting fetal dopaminergic cells and improving their survival after transplantation.
Bone healing and spinal fusion
Authors: Pilitsis Julie G. , Lucas David R. , Rengachary Setti R.
Published: January 2008

Bone is a tissue that constantly undergoes deposition, resorption of stromal matrix, and remodeling. These processes may be altered by a variety of chemical, mechanical, cellular, and pathological mechanisms. Understanding the physiology of bone healing and the mechanisms affecting this process is important not only when evaluating normal skeletal development but also when initiating fracture repair. Because the ultimate success of spinal fusions involves creation of an osseous union, we focus this review on the anatomy and physiology of bone under physiological conditions, normal bone healing and mechanisms that alter it, and available adjuvant therapies that may enhance healing potential in a clinical setting.
The use of electrical stimulation to enhance spinal fusion
Authors: Morone Michael A. , Feuer Henry
Published: January 2008

The goal of spinal arthrodesis is a solid osseous union across one or more spinal segments. A solid bone union after arthrodesis is commonly known as a spinal fusion. Surgeons have begun to understand the biomechanical and biological factors that influence the bone-healing process. One of the most commonly used adjuncts is spinal instrumentation. Instrumentation has increased the spinal fusion rate; however, fusion failure (that is, nonunion or pseudarthrosis) remains significant. A less commonly used adjunct is electrical stimulation (ES). Investigators in experimental studies have demonstrated the beneficial effects of ES on increasing the fusion rate. In this review the authors discuss the evidence concerning the benefits of ES as an adjunct to spinal arthrodesis. In addition, the different types of ES devices are described along with the current experimental and clinical evidence for each type of device.
History of surgery for the correction of spinal deformity
Authors: Mohan Avinash Lalith , Das Kaushik
Published: January 2008

During the last century the technological advances in the field of spinal surgery had a dramatic impact on the treatment of spinal deformity in children and adults. Before the advent of medications and vaccines to treat and/or prevent tuberculosis and poliomyelitis, patients suffering from these disorders often became incapacitated by the resulting kyphoscoliosis. In the early 1900s Lange began to address this problem mechanically by using foreign materials to stabilize the spine internally. In the 1950s and 1960s, owing to the efforts of Harrington and others, the process evolved to create the first generation of modern spinal instrumentation. The Harrington rod was able to correct a spinal deformity primarily through distraction. In the next wave of advances, some of the shortcomings of Harrington rods were addressed. Segmental fixation involving sublaminar wires was introduced in the 1970s by Luque. Anterior approaches and instrumentation-related techniques developed by Zielke and colleagues as well as Dywer and coworkers in the late 1960s and mid-1970s allowed for better correction of deformity with immobilization of fewer motion segments compared with posterior surgery. Transpedicular fixation of the spine was popularized by Cotrel and Dubousset in the 1980s; they used the technique to perform segmental stabilization, which better reduces the rotational aspect of a deformity. Finally, in the mid-1990s, thoracoscopic techniques were developed and are currently in use for anterior release and placement of instrumentation. The authors review the major technical developments for the surgical treatment of spinal deformity.
Biomechanics of spinal deformity
Authors: Schlenk Richard P. , Kowalski Robert J. , Benzel Edward C.
Published: January 2008

The correction of spinal deformity may be achieved by a variety of methods, each of which has advantages and disadvantages. The goals of spinal deformity surgery include reasonable correction of the curvature, prevention of further deformation, improvement of sagittal and coronal balance, optimization of cosmetic issues, and restoration/preservation of function. The failure to consider all these factors appropriately may result in a suboptimal outcome. Understanding fundamental biomechanical principles involved in the formation, progression, and treatment of spinal deformities is essential in the clinical decision-making process.
Thoracic pedicle screw fixation for spinal deformity
Authors: Rosner Michael K. , Polly David W. , Kuklo Timothy R. , Ondra Stephen L.
Published: January 2008

Techniques to improve segmental fixation have advanced the ability to correct complex spinal deformity. The purpose of instrumentation is to correct spinal deformity or to stabilize the spine to enhance the long-term biological fusion. The ultimate goal of spinal deformity surgery is the creation of a stable, balanced, pain-free spine centered over the pelvis in the coronal and sagittal planes. The minimum number of segments should be fused. These concepts remain challenging in the setting of deformity and instability. Successful results can be obtained if the surgeon understands the technology available, its capabilities, biological limitations, and the desired solution.

The authors prefer to use thoracic pedicle screws when treating patients with spinal deformity because they provide greater corrective forces for realignment. This allows shorter-segment constructs and the possibility of true derotation in correction. In this article the authors focus on the use of thoracic transpedicular screw fixation in the management of complex spinal disorders and deformity.
Spinal instability and deformity due to neoplastic conditions
Authors: Fourney Daryl R. , Gokaslan Ziya L.
Published: January 2008

In addition to tumor resection, a major goal of spine surgery involving tumors is the preservation or achievement of spinal stability. The criteria defining stability, originally developed for use in trauma, are not directly applicable in the setting of neoplasia. The authors discuss the most common patterns of tumor-related instability and deformity at all levels of the spinal column and review the surgical options for treatment.
Convection-enhanced delivery in clinical trials
Authors: Hall Walter A. , Rustamzadeh Edward , Asher Anthony L.
Published: January 2008

The poor prognosis associated with the current management of malignant gliomas has led investigators to develop alternative treatments such as targeted toxin therapy. The optimal method for administering these agents is under development but appears to be convection-enhanced delivery (CED).

The direct intratumoral infusion of targeted toxins was first performed in nude mouse flank tumor models of human malignant glioma. After the demonstration of in vivo efficacy, these potent cytotoxic compounds were tested in Phase I and Phase II clinical trials.

Using a high-flow microinfusion technique, volumes of up to 180 ml were infused by CED through catheters placed directly into brain tumors. Minor systemic toxicity was seen in the form of hepatic enzyme elevation. Neural toxicity manifested as seizure activity and hemiparesis resulted from peritumoral edema that followed the completion of the infusion. Peritumoral toxicity was believed to be more related to the concentration of the infused immunotoxin than to the infusion volume. In approximately half of patients treated with CED a stable disease course, a partial response, or a complete response was demonstrated in some clinical trials.

Targeted toxin therapy has clinical efficacy in patients with malignant gliomas. Convection-enhanced delivery appears to represent an effective method for administering these agents in patients with malignant brain tumors.
Complications associated with lumbar stenosis surgery in patients older than 75 years of age
Authors: Wang Michael Y. , Green Barth A. , Shah Sachin , Steven Vanni D.O. , Levi Allan D. O.
Published: January 2008

Object

An aging population will require that surgeons increasingly consider operative intervention in elderly patients. To perform this surgery safely will require an understanding of the factors that predict successful outcomes as well as complications.

Methods

Records of patients older than the age of 75 years who underwent lumbar spinal stenosis surgery were retrospectively reviewed. Preexisting medical illnesses were analyzed using the Charlson Weighted Comorbidity Index. Ambulatory function was rated on a four-point scale. Statistical analysis was performed using a one-tailed t-test with unpaired variance.

Eighty-eight patients treated between 1994 and 2001 were identified. Forty-five percent were women and 52 patients underwent spinal fusion. The follow-up period averaged 21 months. Back pain was present preoperatively in 89%; after surgery 43% experienced complete relief and 33% partial improvement. Leg pain was present preoperatively in 98%; after surgery 43% experienced complete relief and 42% partial improvement. Of the 33 patients with preoperative gait disturbances, 61% improved at least one point on the ambulatory scale. Wound complications and systemic complications were demonstrated in 24 and 16 patients, respectively. There were no deaths. Age (p = 0.322), number of fused levels (p = 0.371), and the number of laminectomy levels (p = 0.254) were not predictive of complications. Length of operative time (p = 0.003) and the CharlsonWeighted Comorbidity Index score (p = 0.088) were associated with both systemic and wound complications.

Conclusions

Surgery in patients older than age 75 years can be conducted safely and with similar outcome rates as in younger patients. The CharlsonWeighted Comorbidity Index score and operative time were predictive of the risk of complications.
Current neurosurgical indications for saphenous vein graft bypass
Authors: Friedman Jonathan A. , Piepgras David G.
Published: January 2008

Object

Vascular bypass is performed in neurosurgery for a variety of pathological entities, including extracranial atherosclerotic disease, extra- and intracranial aneurysms, and tumors involving the carotid artery (CA) at the skull base or cervical regions. Creation of an interposition saphenous vein graft (SVG) is the typical method of choice when the superficial temporal artery is not an option.

Methods

One hundred thirty consecutive patients treated with SVG between July 1988 and December 2002 at the Mayo Clinic were studied. A total of 130 procedures were performed in 130 patients. The indications were intracranial aneurysm in 51 patients (39%), CA occlusive disease in 36 (28%), extracranial CA aneurysm in 17 (13%), tumors involving the cervical CA in 11 (8%), vertebral artery occlusive disease in eight (6%), and other indications in six patients (5%). Among patients treated for intracranial aneurysms, 43 harbored giant aneurysms (> 25 mm in widest diameter) whereas the remaining eight patients harbored aneurysms that were large (15–25 mm in widest diameter). Among patients with CA occlusive disease, high-grade stenosis at the CA bifurcation was present in 29 and CA occlusion was demonstrated in seven.

Conclusions

The use of SVG bypass remains a valuable component of the neurosurgical armamentarium for a variety of pathological entities. Despite a general trend toward decreased use because of improved endovascular technology, surgical facility with this procedure should be maintained.
Interpositional carotid artery bypass strategies in the surgical management of aneurysms and tumors of the skull base
Authors: Liu James K. , Couldwell William T.
Published: January 2008

Cerebral revascularization is an important component in the surgical management of complex skull base tumors and aneurysms. Patients who harbor complex aneurysms that cannot be clipped directly and in whom parent vessel occlusion cannot be tolerated may require cerebrovascular bypass surgery. In cases in which skull base tumors encase the carotid artery (CA) and a resection is desired, a cerebrovascular bypass may be necessary in planned CA occlusion or sacrifice. In this review the authors discuss options for performing high-flow anterograde interposition CA bypass for lesions of the skull base. The authors review three important bypass techniques involving saphenous vein grafts: the cervical-to-petrous internal carotid artery (ICA), petrous-to-supraclinoid ICA, and cervical-to-supraclinoid ICA bypass. These revascularization techniques are important tools in the surgical treatment of complex aneurysms and tumors of the skull base and cavernous sinus.
Conduits for cerebrovascular bypass and lessons learned from the cardiovascular experience
Authors: Liu James K. , Kan Peter , Karwande S. V. , Couldwell William T.
Published: January 2008

Direct cerebral revascularization is an important procedure in the treatment of certain complex aneurysms and skull base tumors when acute sacrifice of the internal carotid artery is required. It likely remains an appropriate treatment in a small subgroup of patients with cerebral ischemia refractory to maximal medical management. Similar to cardiovascular surgery, the choice of a graft conduit is critical for a successful outcome. The standard conduits are interposition vein grafts (usually the greater saphenous vein), free arterial grafts (radial artery), and pedicled arterial grafts (superficial temporal artery). The goal of this review is to summarize the conduits commonly used in cerebral revascularization with emphasis on their patency rates and flow characteristics. Comparisons are made with similar data available in the cardiovascular literature.
Salvage of advanced squamous cell carcinomas of the head and neck: internal carotid artery sacrifice and extracranial–intracranial revascularization
Authors: Feiz-Erfan Iman , Han Patrick P. , Spetzler Robert F. , Lanzino Giuseppe , Ferreira Mauro A. T. , Gonzalez L. Fernando , Porter Randall W.
Published: January 2008

Object

Squamous cell carcinoma (SCC) of the head and neck may involve the carotid artery (CA) in the neck or skull base. Whether tumor resection should be associated with sacrifice of the CA is debatable.

Methods

Records obtained in five consecutive patients (three men, and two women; mean age 58 years, range 47–69 years) treated for recurrent or progressive SCC involving the internal carotid artery (ICA) at the skull base were reviewed retrospectively. The ICA was sacrificed, an extracranial–intracranial (EC–IC) bypass was performed using a saphenous vein graft, and the tumor and involved ICA segment were resected.

Gross-total resection of the SCC was achieved in four cases. One patient died of an acute postoperative stroke due to bypass occlusion and did not undergo tumor resection. No other permanent ischemic or neurological deficits were noted. The other four patients died of tumor progression (survival range 2–40 months, mean 14 months). One patient survived for more than 2 years (2-year overall survival rate 20%). Histological tumor invasion of the CA wall was verified in one of the three evaluated specimens.

Conclusions

A high rate of morbidity and mortality is associated with cases in which skull base CA sacrifice and an EC–IC bypass are performed. Not all resected arteries are shown to have malignant infiltration on histological examination. Better preoperative imaging criteria are needed to define malignant infiltration of the ICA at the skull base. Chemotherapy and radiotherapy without aggressive tumor resection may be an option for these patients.
Radiosurgery for nonfunctioning pituitary adenoma
Authors: Sheehan Jason P. , Kondziolka Douglas , Flickinger John , Lunsford L. Dade
Published: January 2008

Object

Nonfunctioning pituitary adenomas comprise approximately 30% of all pituitary tumors. The purpose of this retrospective study was to evaluate the efficacy and role of gamma knife surgery (GKS) in the treatment of these lesions.

Methods

The authors conducted a review of cases in which GKS was performed at the University of Pittsburgh between 1987 and 2001. Forty-six patients with nonfunctioning pituitary adenomas and with at least 6 months of follow-up data were identified. In 41 of these patients some form of prior treatment such as transsphenoidal resection, craniotomy and resection, or conventional radiation therapy had been conducted. Five patients were deemed ineligible for microsurgery, and GKS served as the primary treatment modality. Endocrinological, ophthalmological, and radiological responses were evaluated. The mean radiation dose to the margin was 16 Gy.

In all patients with microadenomas and 91% of those with macroadenomas tumor control was demonstrated after radiosurgery. Gamma knife surgery had essentially equal efficacy in terms of achieving tumor control in cases of adenomas with cavernous sinus invasion and suprasellar extension. No new endocrinopathies were noted following radiosurgery. In two patients, however, tumor growth and decline in visual function occurred.

Conclusions

Gamma knife surgery is safe and effective in treating nonfunctioning pituitary adenomas. Radiosurgery may serve as a primary treatment modality in some or as a salvage treatment in others. Treatment must be tailored to meet the patient's symptoms, overall health, and tumor morphometry.
Hypophysial transposition (hypophysopexy) for radiosurgical treatment of pituitary tumors involving the cavernous sinus
Authors: Liu James K. , Schmidt Meic H. , Macdonald Joel D. , Jensen Randy L. , Couldwell William T.
Published: January 2008

Stereotactic radiosurgery (SRS) is performed with increasing frequency in the treatment of residual or recurrent pituitary adenomas. Its major associated risk in these cases of residual or recurrent pituitary tumor adjacent to normal functional pituitary gland is radiation exposure to the pituitary, which frequently leads to the development of hypopituitarism. The authors describe a technique of pituitary transposition to reduce the radiation dose to the normal pituitary gland in cases of planned radiosurgical treatment of residual pituitary adenoma within the cavernous sinus. A sellar exploration for tumor resection is performed, the pituitary gland is transposed from the region of the cavernous sinus, and a fat and fascia graft is interposed between the normal pituitary gland and the residual tumor in the cavernous sinus. The residual tumor may then be treated with SRS. The increased distance between the normal pituitary gland and the residual tumor facilitates treatment of the tumor with radiosurgery and reduces radiation exposure to the normal pituitary gland.
Stereotactic radiosurgery for hypersecreting pituitary tumors: part of a multimodality approach
Authors: Jane John A. , Vance Mary Lee , Woodburn C. J. , Laws Edward R.
Published: January 2008

Object

Surgical and medical therapies successfully achieve biochemical remission in the majority of patients with secretory pituitary adenomas. Nevertheless, continued hypersecretion after first-line therapy occurs and requires adjunctive therapy to prevent morbidity and premature mortality. For patients in whom medical and surgical therapy have failed, gamma knife surgery (GKS) is performed with the goal of controlling tumor growth and excess growth hormone (GH) production. The authors report their experience with GKS in patients in whom surgical and medical therapies failed.

Methods

The neuroendocrine service at the University of Virginia has treated 220 patients with secretory adenomas. The authors evaluated the biochemical results in patients with acromegaly followed for greater than 18 months (64 patients) as well as those with Cushing disease (45 patients), Nelson syndrome (14 patients with adequate follow up [27 overall]), and prolactinomas (19 patients) followed for at least 12 months posttreatment. Biochemical remission occurred in 36% of patients with GH-secreting adenomas, 73% of those with Cushing disease, 14% of those with Nelson syndrome, and 11% of those harboring prolactinomas. Recurrence after biochemical remission was documented in four patients with Cushing disease. New hormonal deficits have occurred in 28% of patients with acromegaly, 31% with Cushing disease, 36% with Nelson syndrome, and 21% with prolactinomas. Minor visual deterioration developed in one patient with Cushing disease.

Conclusions

Gamma knife surgery offers an important treatment modality in patients with secretory adenomas refractory to surgical and medical interventions.
Linear accelerator–based radiosurgery for vestibular schwannoma
Authors: Friedman William A. , Foote Kelly D.
Published: January 2008

Despite major advances in skull base surgery and microsurgical techniques, surgery for vestibular schwannoma (VS) carries a risk of complications. Some are inherent to general anesthesia and surgery of any type and include myocardial infarction, pneumonia, pulmonary embolism, and infection. Some are specific to neurosurgery in this area of the brain, and include hydrocephalus, cerebrospinal fluid leak, facial nerve paralysis, facial numbness, hearing loss, ataxia, dysphagia, and major stroke. Even in the hands of very experienced acoustic surgeons, these risks cannot be eliminated.

Radiosurgery provides an outpatient, noninvasive alternative for the treatment of small acoustic schwannomas. Initially radiosurgery was undertaken in “high-risk” patients, including the elderly, those with severe medical comorbidities, and those in whom tumors recurred after surgery. Additionally, a high rate of cranial nerve morbidity was reported. With improvements in dosimetry planning and dose selection, however, authors practicing at radiosurgical centers now report very low complication rates, as well as high tumor control rates.

In this report the authors specifically review the results of linear accelerator–based radiosurgery for VS and compare these outcomes with the best surgical alternatives.
Stereotactic radiosurgery for intracranial meningiomas: indications and results
Authors: Pollock Bruce E.
Published: January 2008

Object

Stereotactic radiosurgery (SRS) has become an important treatment option for patients with intracranial meningiomas. The author reviews the 12-year experience at a single institution and discusses the relative strengths and weakness of this management approach.

Methods

Between January 1990 and December 2002, 330 patients (with 356 tumors) underwent radiosurgery for intracranial meningiomas. One hundred thirty-eight patients (42%) harbored recurrent/residual tumors after having already undergone resection; 192 patients (58%) underwent radiosurgery as primary treatment. The majority of patients (70%) harbored skull base tumors. The median tumor volume was 7.3 cm3 (range 0.5–50.5 cm3). The median tumor margin dose was 16 Gy (range 12–20 Gy). In 278 patients with 297 lesions the mean clinical and imaging follow-up period was 43 months (range 2–138 months). Two hundred seventy-eight tumors (94%) remained stable or decreased in size, and 19 tumors progressed in size. Factors associated with progression were tumor histological type and prior surgery. Treatment-related complications occurred in 8% of the patients and included cranial neuropathies, symptomatic edema, cyst formation, and stenosis of the internal carotid artery. In three patients (1%) tumor dedifferentiation was noted after SRS.

Conclusions

Radiosurgical treatment of meningioma is safe and it has become the primary treatment for patients with small skull base tumors. Further study is needed to determine the long-term tumor control rates after such treatment, especially for patients treated with doses of 14 Gy or less.
Radiosurgery and stereotactic radiotherapy for intracranial meningiomas
Authors: Torres Rodrigo Couto , Frighetto Leonardo , De Salles Antonio A. F. , Goss Brian , Medin Paul , Solberg Timothy , Ford Judith Marianne , Selch Michael
Published: January 2008

Object

The authors report the evolution of linear accelerator (LINAC)–based radiosurgery in the treatment of patients with intracranial meningiomas. They describe the technical aspects as well as clinical and radiological outcomes.

Methods

The authors performed a retrospective review of 161 patients harboring 194 intracranial meningiomas treated with various types of stereotactic irradiation at their institution between May 1991 and July 2002. Clinical and radiological follow-up data (mean follow-up period 32.5 months, range 6–125 months) were obtained in 128 patients (79.5%) with 156 meningiomas (80.4%). There were 88 women and 40 men whose mean age was 57.2 years (range 18–87 years). Stereotactic irradiation was the primary treatment in 44 patients, and 84 patients underwent resection prior to radiosurgery. Stereotactic radiosurgery (SRS) was used to treat 79 lesions and fractionated stereotactic radiotherapy (SRT) was used to treat 77. The mean dose for SRS was 1567 cGy (range 1200–2285 cGy) prescribed to a mean isodose line of 66.6% (range 50–90%). Stereotactic radiotherapy was delivered using a mean dose of 4839 cGy (range 2380–5400 cGy), prescribed to a mean isodose line of 89% (range 50–90%).

The mean follow-up periods were 40 and 24 months in SRS- and SRT-treated patients, respectively. Tumor control was achieved in 58 SRT-treated benign meningiomas (90%) and in 70 SRT-treated lesions (97.2%). In patients with atypical meningiomas a considerably poorer prognosis was seen. Clinical improvement or stabilization of symptoms was observed in the majority of patients. Symptomatic complications were limited to four patients (5%) treated with SRS and four (5.2%) treated with SRT.

Conclusions

Stereotactic irradiation techniques have changed the neurosurgical approach to intracranial meningiomas. Either SRS or SRT delivered as a primary treatment in selected cases of skull base lesions or as an adjuvant after conservative resection has improved the management of these complex intracranial tumors.
Cavernous sinus meningiomas
Authors: Heth Jason A. , Al-Mefty Ossama
Published: January 2008

Cavernous sinus meningiomas were once considered unresectable. The development of microsurgical and skull base techniques as well as advances in anesthesia and neuroradiology have allowed safe and systematic treatment of these lesions. Proper evaluation and patient counseling are required. A thorough understanding of the anatomy and surgical approaches are crucial to success, as is knowledge of the possible adverse outcomes including cranial neuropathy and stroke. The authors discuss these issues in the treatment of cavernous sinus meningiomas.
Functional magnetic resonance imaging for brain mapping in neurosurgery
Authors: Kim Paul E. , Singh Manbir
Published: January 2008

One of the most pertinent applications of the principle primum non nocere (first do no harm) is in the optimization of neurosurgical procedures for patients with resectable lesions. The gold standard for identifying eloquent areas of the brain to be avoided in resections is direct cortical stimulation and somatosensory evoked potential monitoring, which is itself an invasive, cumbersome and difficult technique for mapping these areas. Functional magnetic resonance imaging shows great promise as a viable noninvasive alternative to invasive mapping as well as significant current clinical utility in cases in which it cannot yet fully supplant cortical stimulation methods. Ongoing work is directed toward overcoming technical limitations, improved mapping of complex functions such as language and memory, and mapping of white matter tracts.
Meningiomas: the role of preoperative angiography and embolization
Authors: Dowd Christopher F. , Halbach Van V. , Higashida Randall T.
Published: January 2008

The field of interventional neuroradiology has experienced remarkable technological developments in microcatheters and embolic materials during the past two decades. The realm of meningioma therapy has benefited handsomely from the combination of these technical improvements and the knowledge of experienced practitioners in this field. Transarterial embolization has become a standard procedure in the preoperative management of meningiomas. The authors describe the indications, pretreatment evaluation, techniques, and outcomes when preoperative angiography and embolization are performed in the treatment of these tumors.
Spinal congenital dermal sinus associated with upper thoracic meningocele
Authors: Kara Niyazi Nefi
Published: January 2008

The congenital dermal sinus is an abnormal epithelium-lined sinus tract between the skin surface and deeper tissues. It occurs during neurulation when the neural groove closes to form the neural tube on Day 26 of gestation and results from a failure of neuroectoderm to separate from the cutaneous ectoderm. The most frequent location is the lumbosacral area; an upper thoracic location is quite rare.

This 37-year-old man presented with headache and numbness in both arms. No specific neurological findings were observed. Physical examination revealed a dimple at T-2. Radiography and magnetic resonance imaging of the thoracic spine revealed spina bifida at T1–3, a meningocele, and a dermal sinus tract complex. The treatment approach and outcome in this unusual case are presented.