bluuebunny/crossref_metadata_2025 huggingface dataset:
Cerebral Hemodynamic Parameters for Patients with Neurological Improvements after Extracranial-Intracranial Arterial Bypass Surgery: Evaluation Using Positron Emission Tomography
Authors: Iwama Toru , Hashimoto Nobuo , Hayashida Kohei
Published: July 2004

OBJECTIVE

The purpose of this study was to clarify the hemodynamic features of patients who experienced improved neurological function after extracranial-intracranial arterial bypass surgery. With this aim, we retrospectively analyzed the results of their pre- and postoperative positron emission tomographic studies.

METHODS

This study included 16 patients who exhibited stable neurological dysfunction just before extracranial-intracranial bypass surgery. All underwent pre- and postoperative positron emission tomographic studies. They were divided into groups, i.e., patients who did (Group 1, n = 6) or did not (Group 2, n = 10) manifest postoperative improvements in neurological functions. Positron emission tomographic parameters obtained in the middle cerebral artery territories were compared between the two groups.

RESULTS

Comparison of the preoperative hemodynamic values on the affected side and the contralateral side demonstrated that the mean regional cerebral blood flow values were significantly lower on the affected side in both groups (Group 1, P < 0.005; Group 2, P < 0.05). For Group 1 patients, the mean regional oxygen extraction fraction (rOEF) and regional cerebral blood volume values were significantly higher on the affected side than on the contralateral side (P < 0.01 and P < 0.05, respectively). For Group 2 patients, the mean regional cerebral metabolic rate of oxygen (rCMRO2) value was significantly lower on the affected side than on the contralateral side (P < 0.05). The mean rOEF and rCMRO2 values on the affected side were significantly higher for Group 1 patients, compared with Group 2 patients, before surgery (P < 0.05 and P < 0.05, respectively). The preoperative regional cerebral blood flow and regional cerebral blood volume values on the affected side were similar for the two groups. Postoperative changes in mean regional cerebral blood flow and mean rOEF on the affected side were statistically significant for both groups. The mean rCMRO2 on the affected side for Group 2 was significantly lower than that for Group 1, even after bypass surgery (P < 0.05).

CONCLUSION

Bypass surgery may improve neurological function for patients with significantly elevated rOEF values and rCMRO2 values near the normal level. These hemodynamic parameters may be useful for the identification of candidates for extracranial-intracranial bypass surgery.
Management of Malignant Pineal Germ Cell Tumors with Residual Mature Teratoma
Authors: Friedman Jonathan A. , Lynch James J. , Buckner Jan C. , Scheithauer Bernd W. , Raffel Corey
Published: July 2004

OBJECTIVE

The treatment of intracranial mixed germ cell tumors presents a unique challenge, since eradication of malignant tumor by radiation and/or chemotherapy may spare the benign tumor component. We reviewed our surgical experience with residual malignant pineal germ cell tumors after neoadjuvant therapy.

METHODS

Between 1987 and 1997, 16 patients with malignant intracranial germ cell tumors were treated at the Mayo Clinic with a protocol of neoadjuvant chemotherapy and radiation therapy. After the diagnosis was confirmed by histopathological examination, all patients were treated with four cycles of etoposide and cisplatin as well as external beam radiation therapy (range, 3030–5940 cGy). Six patients had an incomplete response to therapy, as demonstrated by observation of residual tumor on magnetic resonance imaging scans. Initial pathology in these six patients was germinoma in four and combinations of yolk sac tumor, embryonal carcinoma, malignant teratoma, and germinoma in two. Two patients had synchronous pineal and suprasellar tumors, with leptomeningeal dissemination. Tumor markers were elevated in four of the six patients at presentation.

RESULTS

All patients with residual pineal tumors underwent surgical resection via an infratentorial, supracerebellar approach. Pathological examination revealed mature teratoma in five patients and amorphous debris in one patient. No patient had recurrent malignancy. Significant neurological morbidity occurred in one patient, with no mortality. At a mean follow-up of 23 months, no recurrence on magnetic resonance imaging has been documented.

CONCLUSION

Residual pineal tumor occurring after treatment of malignant intracranial germ cell tumor with neoadjuvant therapy is likely to be mature teratoma. Operative resection of these benign recurrences is safe and effective.
Percutaneous Controlled Radiofrequency Trigeminal Rhizotomy for the Treatment of Idiopathic Trigeminal Neuralgia: 25-year Experience with 1600 Patients
Authors: Kanpolat Yücel , Savas Ali , Bekar Ahmet , Berk Caglar
Published: July 2004

OBJECTIVE

The objective of this study was to evaluate the effectiveness of percutaneous, controlled radiofrequency trigeminal rhizotomy (RF-TR). The outcome of 1600 patients with idiopathic trigeminal neuralgia after RF-TR was analyzed after a follow-up period of 1 to 25 years.

METHODS

A total of 1600 patients with idiopathic trigeminal neuralgia underwent 2138 percutaneous radiofrequency rhizotomy procedures between 1974 and 1999. Sixty-seven patients had bilateral idiopathic trigeminal neuralgia, and 36 of them were treated with bilateral RF-TR; 1216 patients (76%) were successfully managed with a single procedure, and the remainder were treated with multiple procedures. Benzodiazepines and narcotic analgesics were used for anesthesia because patient cooperation during the procedures was essential so that the physician could create selective, controlled lesions.

RESULTS

The average follow-up time was 68.1 ± 66.4 months (range, 12–300 mo). Acute pain relief was accomplished in 97.6% of patients. Complete pain relief was achieved at 5 years in 57.7% of the patients who underwent a single procedure. Pain relief was reported in 92% of patients with a single procedure or with multiple procedures 5 years after the first rhizotomy was performed. At 10-year follow-up, 52.3% of the patients who underwent a single procedure and 94.2% of the patients who underwent multiple procedures had experienced pain relief; at 20-year follow-up, 41 and 100% of these patients, respectively, had experienced pain relief. No mortalities occurred. After the first procedure was performed, early pain recurrence (<6 mo) was observed in 123 patients (7.7%) and late pain recurrence was observed in 278 patients (17.4%). Complications included diminished corneal reflex in 91 patients (5.7%), masseter weakness and paralysis in 66 (4.1%), dysesthesia in 16 (1%), anesthesia dolorosa in 12 (0.8%), keratitis in 10 (0.6%), and transient paralysis of Cranial Nerves III and VI in 12 (0.8%). Permanent Cranial Nerve VI palsy was observed in two patients, cerebrospinal fluid leakage in two, carotid-cavernous fistula in one, and aseptic meningitis in one.

CONCLUSION

Percutaneous, controlled RF-TR represents a minimally invasive, low-risk technique with a high rate of efficacy. The procedure may safely be repeated if pain recurs.
Retrosigmoid Approach to Acoustic Neuroma (Vestibular Schwannoma)
Authors: Ojemann Robert G.
Published: July 2004

THE RETROSIGMOID APPROACH for the microsurgical removal of an acoustic neuroma (vestibular schwannoma) is described, and perioperative medical management of the patient is discussed. The techniques for monitoring facial and cochlear nerve function are presented. The supine-oblique position, skin incision, bone removal, dural opening, and initial exposure are outlined. Important points in the technique for removing acoustic neuromas and preserving hearing, when possible, are described and illustrated.
Image-guided Transorbital Roof Craniotomy via a Suprabrow Approach: A Surgical Series of 72 Patients
Authors: Shanno George , Maus Marlon , Bilyk Jurij , Schwartz Steven , Savino Peter , Simeone Frederick , Goldman H. Warren
Published: July 2004

OBJECTIVE

Many subfrontal and orbitofrontal craniotomy techniques have been developed. We present our results with the transorbital roof craniotomy, a frontal craniotomy that incorporates the orbital roof and is performed via a suprabrow incision. This technique was used in 72 patients, primarily for tumor resection.

METHODS

Charts were retrospectively reviewed for all patients undergoing transorbital procedures. A total of 72 patients underwent 82 transorbital craniotomies from September 1995 to July 1999. The primary indication for the transorbital approach was mass lesion of the orbit, anterior fossa, or parasellar region.

RESULTS

A total of 47 women and 25 men with a mean age of 53 years underwent 82 procedures. The primary pathological finding was meningioma, which occurred in 40 patients (55.6%), followed by craniopharyngioma (6.9%), pituitary macroadenoma (6.9%), schwannoma (5.5%), and hemangioma (5.5%). Simpson Grade I or II resection was achieved in 54% of patients, with Simpson Grade III to V resection achieved in the remaining 46%. Forty-one patients presented with visual loss in 43 cases, with 44.2% experiencing postoperative visual improvement, 46.5% remaining unchanged, and 9.3% worsening. Overall morbidity was 18.4%, with cerebrospinal fluid leak being the most common complication (6.6%). No patients died.

CONCLUSION

The transorbital roof craniotomy is an evolutionary approach that provides excellent exposure to the orbit, anterior fossa, and parasellar region with little significant morbidity and, in our series, no mortality. Although we have used this approach primarily for resection of mass lesions, future directions for this procedure will likely lie in treating vascular lesions and lesions of the interpeduncular fossa.
Meningeal Hemangiopericytoma: A Retrospective Study of 21 Patients with Special Review of Postoperative External Radiotherapy
Authors: Dufour Henry , Métellus Philippe , Fuentes Stéphane , Murracciole Xavier , Régis Jean , Figarella-Branger Dominique , Grisoli François
Published: July 2004

OBJECTIVE

To specify that postoperative radiotherapy is useful for preventing local recurrence and neuraxis recurrence of surgically treated meningeal hemangiopericytomas.

METHODS

We retrospectively studied 21 patients with meningeal hemangiopericytoma who were followed in our department during a 34-year period. In 17 patients, the meningeal hemangiopericytoma was intracranial, and in 4 there was an intradural extramedullary localization. These groups were studied separately.

RESULTS

Of the 17 patients with intracranial hemangiopericytoma, all underwent surgery; 8 also underwent radiotherapy (5000–6400 rads) (Group I), and 9 did not (Group II). The mortality rate was zero for Group I patients and 55% for Group II. The mean local recurrence rate was 52% (12.5% in Group I and 88% in Group II; P < 0.05). Neuraxis recurrences occurred in two patients in Group II, and none occurred in Group I (P = 0.4). Peripheral metastasis took place in two patients (22%) in Group II and in one patient (12.5%) in Group I (P = 0.5). Of the four patients with intradural extramedullary hemangiopericytoma, all underwent surgery. Two patients received 4000 rads of radiotherapy after intervention. No patient in this group had a recurrence.

CONCLUSION

For patients with intracranial meningeal hemangiopericytoma, surgical removal followed by external radiotherapy reduced the risk of local recurrence. It was not demonstrated that postoperative radiotherapy protected against neuraxis metastasis. Radiotherapy did not protect against peripheral metastasis, which can occur up to several years after the first operation. It appears that radiotherapy after surgery for local or neuraxis recurrence did not avoid further recurrence. Radiosurgery is indicated for recurrent tumors measuring less than 25 mm in greatest diameter. For intradural extramedullary localizations, the value of postoperative radiotherapy is more questionable.
Comparison of Thalamotomy and Pallidotomy for the Treatment of Dystonia
Authors: Yoshor Daniel , Hamilton Winifred J. , Ondo William , Jankovic Joseph , Grossman Robert G.
Published: July 2004

OBJECTIVE

Thalamotomy and, more recently, pallidotomy have been used to treat selected patients with intractable dystonia, although few studies have compared the effectiveness of these two surgical procedures. In this study, we compare our results using thalamotomy and pallidotomy to treat patients with different forms of dystonia, and we discuss our results in the context of other published series.

METHODS

Thirty-two patients with intractable dystonia underwent thalamotomy (n = 18) or pallidotomy (n = 14). Dystonia was classified according to cause and distribution, and each patient was evaluated postoperatively at two or more time points, using a global outcome scale.

RESULTS

Although comparisons are limited by differences between the two surgical groups, including longer follow-up periods for the thalamotomy group, differences in symptom distribution, and more bilateral procedures for the pallidotomy group, patients with primary dystonia who underwent pallidotomies demonstrated significantly better long-term outcomes than did patients who underwent thalamotomies (P = 0.0467). Patients with secondary dystonia experienced more modest improvements after either procedure, with little or no difference in outcomes between the two procedures.

CONCLUSION

For patients with primary dystonia, pallidotomy seems to result in better outcomes than does thalamotomy.
Primary Myxoma of the Temporal Bone in a 17-Year-Old Boy: Case Report
Authors: Osterdock Renatta J. , Greene Sandea , Mascott Christopher R. , Amedee Ronald , Crawford Byron E.
Published: July 2004

OBJECTIVE AND IMPORTANCE

Only two cases of primary intracranial myxomas have been described previously in the literature: one patient had a primary intracranial myxoma in the pituitary fossa, and the other patient's myxoma was located in the posterior fossa.

CLINICAL PRESENTATION

A rare case of primary myxoma of the temporal bone in a 17-year-old boy is described. The patient presented with a history of progressive left-sided hearing loss and increasing headaches of a few months' duration.

INTERVENTION

An initial draining procedure in the left ear revealed extant mucous material, and further investigation showed a large calcified lesion involving the petrous and temporal bones and filling the middle fossa. At surgery, a large mucoid-appearing tumor was removed. The tumor pathology revealed a primary myxoma with bone and meningeal involvement. No clinical or histopathological evidence that it was a metastatic lesion was found.

CONCLUSION

The features of myxomas on computed tomographic and magnetic resonance imaging, the histopathology, and surgical considerations are discussed.
Surgical Management of Clinoidal Meningiomas
Authors: Lee Joung H. , Jeun Sin-Soo , Evans James , Kosmorsky Gregory
Published: July 2004

OBJECTIVE

Surgical outcome has been less than desirable in the management of patients with clinoidal meningiomas in the past, and little attention has been directed at improving their visual function. The purpose of this article is to advocate an available cranial base technique for removing these difficult tumors and to delineate the technique's advantages that aid in achieving an improved extent of tumor resection and enhancing the patients' overall outcome, particularly their visual outcome.

METHODS

A retrospective analysis was performed on 15 consecutive patients with clinoidal meningiomas (including a patient with hemangiopericytoma) who underwent surgical resection at the Cleveland Clinic Foundation between June 1995 and January 2000. A cranial base technique consisting of extradural anterior clinoidectomy, coupled with optic canal unroofing and optic sheath opening, was used in 13 patients, and standard pterional craniotomy was used in 2. Eight of 15 patients had significant visual deficits preoperatively. All patients had thorough preoperative and postoperative ophthalmological evaluations. The follow-up period ranged from 6 to 60 months (mean, 37.2 mo).

RESULTS

Total resection was achieved in 13 (86.7%) of the 15 patients in this series, and the majority of the patients with preoperative visual impairment experienced significant improvement (6 of 8 patients; 75%).

CONCLUSION

In the majority of patients with clinoidal meningiomas, total resection may be achieved with minimal complications. For large tumors encasing the optic nerve and internal carotid artery, or for those tumors causing preoperative visual impairment, use of the cranial base technique delineated in this study may lead to significant improvement in the patients' visual and overall outcomes.
Intraoperative Magnetic Resonance Imaging Combined with Neuronavigation: A New Concept
Authors: Nimsky Christopher , Ganslandt Oliver , Kober Helmut , Buchfelder Michael , Fahlbusch Rudolf
Published: July 2004

OBJECTIVE

Intraoperative image data may be used not only to evaluate the extent of a tumor resection but also to update neuronavigation, compensating for brain shift. To date, however, intraoperative magnetic resonance imaging (MRI) can be combined only with navigation microscopes that are separated from the magnetic field, thus requiring time-consuming intraoperative patient transport. To help solve this problem, we investigated whether a new navigation microscope can be used within the fringe field of the MRI scanner.

METHODS

The navigation microscope was placed at the 5-G line of a 0.2 MRI device. Patients were positioned lying down directly on the table of the scanner, with their heads placed approximately 1.5 m from the center of the magnet, fixed in an MRI-compatible ceramic head holder. Standard operating instruments were used. For intraoperative imaging, we slid the table into the center of the magnet in less than 30 seconds.

RESULTS

By use of this setup, we operated on 22 patients. In all patients, anatomic neuronavigation could be used in combination with intraoperative MRI. In addition, in 12 patients, functional data from magnetoencephalographic or functional MRI studies were integrated, resulting in functional neuronavigation. We did not encounter adverse effects of the low magnetic field during navigation. Moreover, intraoperative imaging was not disturbed by the navigation microscope and vice versa.

CONCLUSION

Functional neuronavigation and intraoperative MRI can be used essentially simultaneously without the need for lengthy intraoperative patient transport. The combination of intraoperative imaging with functional neuronavigation offers the opportunity for more radical resections and fewer complications.
Mycotic Aneurysm of the Carotid Bifurcation in the Neck: Case Report and Review of the Literature
Authors: Nader Remi , Mohr Gérard , Sheiner Nathan M. , Tampieri Donatella , Mendelson Jack , Albrecht Steffen
Published: July 2004

OBJECTIVE AND IMPORTANCE

Mycotic aneurysms of the extracranial carotid artery are rare and difficult to diagnose. A search of the world literature published since 1966 reveals at least six cases of mycotic carotid aneurysms due to a Salmonella septicemia. We present an exceptional case of mycotic pseudoaneurysm of the bifurcation of the carotid artery due to Salmonella septicemia and discuss the pathogenesis as well as various aspects of the diagnosis and surgical management.

CLINICAL PRESENTATION

A 68-year-old man presented in Poland with Salmonella sepsis; 1 month later, he was admitted to the emergency department of the Sir Mortimer B. Davis-Jewish General Hospital in Montreal with a bulky and pulsatile right cervical mass. An angiogram and a computed tomographic scan revealed a voluminous and partially thrombosed aneurysm the size of a tangerine originating from the posterior aspect of the carotid junction.

INTERVENTION

Balloon trapping was attempted at the Montreal Neurological Hospital. Subsequently, the patient developed a significant neurological deficit, which was quickly reversed by the administration of hypertensive, hypervolemic, and hemodilution therapy. Thereafter, the pseudoaneurysm was resected surgically, and the internal and external carotid arteries were sacrificed. Pathological examination of the excised specimen of the carotid junction revealed a pseudoaneurysm. Bacterial culture of the lesion showed growth of Salmonella.

CONCLUSION

The postoperative course was satisfactory except for laryngeal paralysis due to involvement of the vagus nerve. Four months later, a computed tomographic scan showed only small lacunae in both centra semiovale.
Carotid Endarterectomy with External Shunt: A New Device and Indication for Use: Technical Note
Authors: Uno Masaaki , Nishi Kyoko , Shinno Kiyohito , Nagahiro Shinji
Published: July 2004

OBJECTIVE

We designed a new external shunt system and evaluated its indications and efficacy in patients undergoing carotid endarterectomy (CEA).

METHODS

In 8 of 332 CEA procedures, external shunts were placed between the common carotid artery and the internal carotid artery (ICA). This procedure was implemented for one of two indications: 1) a change in electroencephalographic and/or somatosensory evoked potential readings immediately after ICA occlusion, or 2) elongation of the ICA made safe insertion of an internal shunt impossible. In addition, a shunt was placed between the common carotid artery and the external carotid artery to establish collateral circulation from the external carotid artery to the intracranial circulation, which is essential during ICA occlusion.

RESULTS

All external shunts were functional, and electroencephalography and somatosensory evoked potentials demonstrated no significant abnormalities during the CEAs. All patients awoke from surgery without manifestation of new neurological deficits.

CONCLUSION

Our new external shunt device proved safe and efficacious in cases that did not permit the placement of an internal shunt.
Venous Congestion Is a Major Cause of Neurological Deterioration in Spinal Arteriovenous Malformations
Authors: Kataoka Hiroharu , Miyamoto Susumu , Nagata Izumi , Ueba Tetsuya , Hashimoto Nobuo
Published: July 2004

OBJECTIVE

Although venous congestion is considered to be a major cause of progressive myelopathy in patients with spinal dural arteriovenous fistulae (DAVFs), the neurological deterioration in patients with spinal intradural arteriovenous malformations (AVMs) has been attributed to hemorrhage or to vascular steal. To reexamine this theory, we analyzed our own cases of spinal vascular diseases.

METHODS

In 24 patients with spinal vascular diseases, those who demonstrated progressive myelopathy with T2 hyperintensity in the spinal cord on magnetic resonance imaging (MRI) were diagnosed as patients with congestive myelopathy. We further examined the clinical courses, MRI findings, and reversibility of these cases.

RESULTS

Venous congestion was judged to be a cause of neurological deterioration in 13 patients (7 DAVFs, 6 intradural AVMs). The T2 signals on these patients' MRI scans were located in the center and extended over several levels not corresponding to distribution of ischemia due to arterial steal. Of the patients who were diagnosed with congestive myelopathy, no differences between those with DAVFs and those with intradural AVMs were apparent in terms of clinical manifestations and reversibility. Eight (four DAVFs, four intradural AVMs) of 13 patients experienced neurological improvement after treatment. All patients with poor outcomes had intervals from onset of more than 3 years and showed contrast enhancement of the spinal cord on MRI studies.

CONCLUSION

Spinal intradural AVMs as well as spinal DAVFs can be a cause of venous congestive myelopathy. Regardless of its etiology, congestive myelopathy is potentially reversible if properly diagnosed and treated.
Radiosurgery for the Treatment of Recurrent Central Neurocytomas
Authors: Anderson Richard C. , Elder James B. , Parsa Andrew T. , Issacson Steven R. , Sisti Michael B.
Published: July 2004

OBJECTIVE

Central neurocytomas are benign neoplasms with neuronal differentiation typically located in the lateral ventricles of young adults. Although the treatment of choice is complete surgical excision, patients may experience local recurrence. Adjuvant therapy for patients with residual or recurrent tumor has included reoperation, radiotherapy, or chemotherapy. To avoid the side effects of conventional radiotherapy in young patients, we present a series of patients with clear evidence of tumor progression who were treated with gamma knife radiosurgery.

METHODS

Four patients (ages 20–49 yr; mean, 28 yr) who presented with an intraventricular mass on magnetic resonance imaging scans and underwent craniotomy for tumor resection were reviewed retrospectively. Histopathological analysis confirmed central neurocytoma in all cases. Each patient was followed up clinically and radiographically with serial magnetic resonance imaging. When radiographic signs of tumor progression were evident, patients were treated with radiosurgery.

RESULTS

Complete radiographic tumor resection was achieved in all patients. There were no major postoperative complications. Local tumor progression was detected on magnetic resonance imaging scans 9 to 25 months after surgery (median, 17.5 mo). All patients achieved complete response to radiosurgery with reduction in tumor size. There have been no complications from radiosurgery. Follow-up ranged from 12 to 28 months (mean, 16.5 mo) after radiosurgery, and from 24 to 84 months (mean, 54.5 mo) after initial presentation.

CONCLUSION

Radiosurgery with the gamma knife unit provides safe and effective adjuvant therapy after surgical resection of central neurocytomas. Radiosurgery may eliminate the need for reoperation and avoid the possible long-term side effects from conventional radiotherapy in young patients.
Treatment of Idiopathic Trigeminal Neuralgia: Comparison of Long-term Outcome after Radiofrequency Rhizotomy and Microvascular Decompression
Authors: Tronnier Volker M. , Rasche Dirk , Hamer Jürgen , Kienle Anna-Lena , Kunze Stefan
Published: July 2004

OBJECTIVE

To evaluate the long-term outcome of patients after either percutaneous trigeminal rhizotomy or microvascular decompression (MVD) for idiopathic trigeminal neuralgia at a single institution.

METHODS

From 1977 to 1997, 316 radiofrequency lesion procedures and 378 MVDs were performed. Questionnaires were sent to all patients who were alive in 1981, 1982, 1992, and 1998. For all other patients, interviews were conducted with their relatives and general practitioners. A retrospective comparative analysis was performed with Kaplan-Meier probability curves as of the latest follow-up date. In addition, 80 patients who underwent MVD were examined postoperatively with quantitative sensory measurements by use of von Frey hairs.

RESULTS

Two hundred twenty-five patients who underwent MVD and 206 patients who underwent radiofrequency could be analyzed retrospectively in detail. Overall, there was a 50% risk for recurrence of pain 2 years after percutaneous radiofrequency rhizotomy. Conversely, 64% of patients who underwent MVD remained completely pain free 20 years postoperatively. Patients without sensory impairment after MVD were pain free significantly longer than patients who experienced postoperative hypesthesia or partial rhizotomy.

CONCLUSION

Because it is curative and nondestructive, MVD is considered the treatment of choice for trigeminal neuralgia in otherwise healthy people. In our study, it proved to be a more effective and long-lasting procedure for patients with typical trigeminal neuralgia than radiofrequency rhizotomy. Patients without postoperative sensory deficit remained pain free significantly longer, which is a strong argument against the “trauma” hypothesis of this procedure.
Microsurgery for Cerebral Arteriovenous Malformations: A Dissection Technique and Its Theoretical Implications
Authors: Hashimoto Nobuo
Published: July 2004

SURGICAL RESECTION OF cerebral arteriovenous malformations is often complicated by persistent bleeding from the nidus, which is difficult to manage. It has often been mentioned that the difficulty of hemostasis is caused by the fragile and pathological nature of vessels of the nidus. This may be one reason, but I hypothesize that the dissection procedure, which involves coagulation of the surface of the nidus, may cause obstruction of intranidal drainage and that this may cause increased intranidal pressure, especially at the late stage of resection. In operating on patients with cerebral arteriovenous malformations recently, I made an effort not to coagulate the surface of the nidus, and this technique has diminished hemorrhage problems effectively. I illustrate this technique herein with a resected specimen and plastic casts of the lesion.
Fluoroscopic Frameless Stereotaxy for Transsphenoidal Surgery
Authors: Jane John A. , Thapar Kamal , Alden Tord D. , Laws Edward R.
Published: July 2004

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.
Combined Oligodendroglioma/Pleomorphic Xanthoastrocytoma: A Probable Collision Tumor: Case Report
Authors: Perry Arie , Scheithauer Bernd W. , Szczesniak David M. , Atkinson John L.D. , Wald John T. , Hammak Julie E.
Published: July 2004

OBJECTIVE AND IMPORTANCE

We report the first case of combined oligodendroglioma and pleomorphic xanthoastrocytoma.

CLINICAL PRESENTATION

A female college student and competitive cross-country runner presented to the Mayo Clinic at age 18 years with complaints of progressive headache and visual disturbances. Neuroimaging revealed a heavily calcified left parieto-occipital mass with focal enhancement and remodeling of the overlying calvarium.

INTERVENTION

A histological examination of the nearly gross total resection specimen disclosed a low-grade oligodendroglioma discretely abutting a superficially situated focus of pleomorphic xanthoastrocytoma. Ten months thereafter, a recurrence was suspected on the basis of the detection of a new focus of nodular enhancement. This lesion stabilized after radiation therapy, and the patient is well, without apparent residual disease 2.8 years after surgery.

CONCLUSION

This unique neoplasm is presumed to represent a collision tumor, its biological behavior being similar to that of oligodendroglioma alone. However, the possibility of an unusual, mixed oligoastrocytoma with pleomorphic xanthoastrocytoma as the astrocytic component cannot be excluded entirely. Potentially, both components have the capacity for recurrence and anaplastic transformation.
Meningeal Solitary Fibrous Tumor as an Unusual Cause of Exophthalmos: Case Report and Review of the Literature
Authors: Ahn Jung Yong , Shim Jeong Yun , Yang Woo Ick , Kim Tai Seung
Published: July 2004

OBJECTIVE AND IMPORTANCE

We report an extremely rare case of a patient with meningeal solitary fibrous tumor with orbital involvement presenting as unilateral exophthalmos. This rare tumor should be considered in the differential diagnosis for aggressive dural-based lesions.

CLINICAL PRESENTATION

A 54-year-old man presented with a protruded eyeball on the right side and left hemiparesis. Computed tomography and magnetic resonance imaging demonstrated a huge mass, markedly enhanced in and around the right anterior clinoid process, which extended to the orbit and middle cranial fossa. Cerebral angiography revealed a richly vascular tumor fed by branches of both the right external and internal carotid arteries. A presumptive diagnosis of meningioma or hemangiopericytoma was considered.

INTERVENTION

The tumor was exposed through an orbitozygomatic approach. At surgery, the tumor was grossly firm to hard and had destroyed the dura, orbital roof, anterior clinoid process, temporal bone, and muscle. Histological analysis revealed that the tumor was composed of spindle-cell proliferation in a collagen-rich background, but it exhibited regional variations. The vascular network demonstrated irregular vascular lumina with a “hemangiopericytoma-like” pattern. Histological features included high cellularity and a high degree of pleomorphism. Immunohistochemical analysis of the tumor demonstrated diffuse positive staining for CD34 and vimentin. The tumor displayed no positive staining for cytokeratin, epithelial membrane antigen, glial fibrillary antigenic protein, S-100 protein, and factor XIII.

CONCLUSION

Meningeal solitary fibrous tumor is considered a unique pathological entity. Wider use of immunohistochemical screening should enable analysis of the real incidence of these tumors; larger series and longer follow-up duration will allow conclusions to be drawn regarding treatment and prognosis. Differential diagnosis is discussed and the literature is reviewed.
Exclusively Epidural Arteriovenous Fistula in the Cervical Spine with Spinal Cord Symptoms: Case Report
Authors: Asai Jun-cihiro , Hayashi Takaki , Fujimoto Tsukasa , Suzuki Ryuta
Published: July 2004

OBJECTIVE AND IMPORTANCE

We describe the case of an epidural arteriovenous fistula (AVF) in the cervical spine draining only into the epidural and paravertebral plexus. An entirely epidural AVF having such drainage is extremely rare.

CLINICAL PRESENTATION

A 24-year-old man presented with a 4-month history of gradually progressive sensory and motor disturbances of the upper and lower extremities. Magnetic resonance imaging and magnetic resonance angiography revealed a peridural vascular lesion within the canal compressing the spinal cord from C5 to T2. Diagnostic angiography revealed a perimedullary and/or dural high-flow AVF, fed mainly by branches of ascending cervical and deep cervical arteries. The fistula drained into the epidural and paravertebral venous plexus without reflux into intradural venous systems.

INTERVENTION

Multiple feeders of the AVF were embolized with a Liquid coil and n-butylcyanoacrylate via a two-step procedure. One week after embolization, the AVF was surgically removed.

CONCLUSION

Interesting points of this case were the exclusively epidural location of the lesion, the exclusively epidural drainage of the AVF, and the etiology of the symptoms. Venous drainage of the fistula had no relation to any dural or intradural veins. Initially, spinal cord and nerve root compression by extradural veins with varicose dilation seemed to cause the radiculopathy and/or the myelopathy, and subsequent myelopathy caused by spinal venous hypertension was believed to be the main etiology in this case.
Temporal Clustering of Hemorrhages from Untreated Cavernous Malformations of the Central Nervous System
Authors: Barker Fred G. , Amin-Hanjani Sepideh , Butler William E. , Lyons Susan , Ojemann Robert G. , Chapman Paul H. , Ogilvy Christopher S.
Published: July 2004

OBJECTIVE

Hemorrhages from cerebral cavernous malformations (CMs) sometimes seem to occur in closely spaced “clusters” interspersed with long hemorrhage-free intervals. Clustering of hemorrhages could affect retrospective assessments of radiosurgery efficacy in prevention of CM rehemorrhage. However, this empirical observation had not been tested quantitatively. To test whether CM hemorrhages tend to cluster, we reviewed pretreatment rebleeding rates after a first symptomatic hemorrhage in CM patients who later underwent surgery or radiosurgery.

METHODS

We performed a retrospective review of 141 patients with CMs who presented with clinically overt hemorrhage, and who subsequently underwent surgery or proton beam radiosurgery during an 18-year period. Statistical models were used to analyze all events per person and identify potential variation in rebleeding risk with time after a previous hemorrhage.

RESULTS

Sixty-three of 141 patients experienced a second hemorrhage before treatment; 16 had additional hemorrhages. Five hundred thirty-eight patient years elapsed between first hemorrhages and treatment. The cumulative incidence of a second hemorrhage after the first CM hemorrhage was 14% after 1 year and 56% after 5 years. During the first 2.5 years after a hemorrhage, the monthly rehemorrhage hazard was 2%. The risk then decreased spontaneously to less than 1% per month, which represents a 2.4-fold decline (P < 0.001). Rehemorrhage rates were higher in younger patients (P < 0.01), but not in females or in patients with deep lesions. Shorter intervals between successive hemorrhages did not predict higher subsequent rehemorrhage risk.

CONCLUSION

The rehemorrhage rate from untreated CMs is high initially, and it decreases 2 to 3 years after a previous hemorrhage. This hazard pattern generates the observed temporal clustering of hemorrhages from untreated CMs.
Measurement of Nitric Oxide and Brain Tissue Oxygen Tension in Patients after Severe Subarachnoid Hemorrhage
Authors: Khaldi Ahmad , Zauner Alois , Reinert Michael , Woodward John J. , Bullock M. Ross
Published: July 2004

OBJECTIVE

Nitric oxide (NO), one of the most powerful endogenous vasodilators, is thought to play a major role in the development of delayed vasospasm in patients with subarachnoid hemorrhage (SAH). However, the role of the production of cerebral NO in patients with SAH is not known. In other SAH studies, NO metabolites such as nitrite and nitrate have been demonstrated to be decreased in cerebrospinal fluid and in plasma.

METHODS

In this study, a microdialysis probe was used, along with a multiparameter sensor, to measure NO metabolites, brain tissue oxygen tension, brain tissue carbon dioxide tension, and pH in the cortex of patients with severe SAH who were at risk for developing secondary brain damage and vasospasm. NO metabolites, glucose, and lactate were analyzed in the dialysates to determine the time course of NO metabolite changes and to test the interrelationship between the analytes and clinical variables.

RESULTS

Brain tissue oxygen tension was strongly correlated to dialysate nitrate and nitrite (r2 = 0.326;P < 0.001); however, no correlation was noted between brain tissue oxygen tension and NO metabolites in cerebrospinal fluid (r2 = 0.018;P = 0.734). No significant correlation between NO production, brain tissue carbon dioxide tension, and dialysate glucose and lactate was observed.

CONCLUSION

Cerebral ischemia and compromised substrate delivery are often responsible for high morbidity rates and poor outcomes after SAH. The relationship between brain tissue oxygen and cerebral NO metabolites that we demonstrate suggests that substrate delivery and NO are linked in the pathophysiology of vasospasm after SAH.
Complications of Epilepsy Surgery after 654 Procedures in Sweden, September 1990–1995: A Multicenter Study Based on the Swedish National Epilepsy Surgery Register
Authors: Rydenhag Bertil , Silander Hans C:son
Published: July 2004

OBJECTIVE

To present the first national multicenter study on complications after epilepsy surgery procedures to include all epilepsy surgery centers in Sweden: Göteborg, Linköping, Lund, Stockholm, Umeå, and Uppsala.

METHODS

Every epilepsy surgery procedure in Sweden is reported to the Swedish National Epilepsy Surgery Register. The report includes relevant social and medical items and complications. A complication is defined as minor if it resolves within 3 months and major if it affects activities of daily living and lasts longer than 3 months. Follow-up data are recorded for 2 years after the operation. Intrinsic checkpoints and external revision validate the register data.

RESULTS

During the inclusion period (September 1990–December 1995), 654 surgical procedures were performed (age range, 6 mo–67 yr). Of these, 205 were invasive electrode procedures (182 first investigations and 23 reinvestigations), and 449 were therapeutic procedures (375 first operations and 74 reoperations). After invasive electrode procedures, only minor complications were reported (6.3%). For all 449 therapeutic procedures (including reoperations), minor complications were reported in 8.9% and major complications in 3.1%. Only one major complication was reported in a patient under the age of 35 years.

CONCLUSION

This is the first national multicenter study on complications after epilepsy surgery. It demonstrates that these procedures as performed at six different centers in Sweden are safe, but also that risk is related to age. In patients younger than age 35 years, the risk for a major complication after invasive subdural strip electrode investigation and epilepsy surgery is low.
High-dose Trigeminal Neuralgia Radiosurgery Associated with Increased Risk of Trigeminal Nerve Dysfunction
Authors: Pollock Bruce E. , Phuong Loi K. , Foote Robert L. , Stafford Scott L. , Gorman Deborah A.
Published: July 2004

OBJECTIVE

Stereotactic radiosurgery is being used with more frequency in the management of patients with trigeminal neuralgia. To improve facial pain outcomes, many centers have increased the prescribed radiation dose to the trigeminal nerve.

METHODS

Between April 1997 and December 1999, 68 patients underwent radiosurgery for trigeminal neuralgia with use of the Leksell gamma knife (Elekta Instruments, Norcross, GA) and a single 4-mm isocenter of radiation. Twenty-seven patients (40%) received 70 Gy (low dose) of irradiation and 41 patients (60%) received 90 Gy (high dose). The groups were similar with regard to age, sex, duration of pain, number of prior surgeries, and preexisting trigeminal deficits. The primary facial pain outcomes for analysis were excellent (pain-free, no medications) and good (pain-free, reduced medications). The mean length of follow-up after radiosurgery was 14.4 months (range, 2–36 mo).

RESULTS

At last follow-up examination, 11 (41%) of the 27 patients with low-dose radiosurgery remained pain-free compared with 25 (61%) of the 41 patients with high-dose radiosurgery (P = 0.17). Additional surgery was performed in 12 low-dose patients (44%) and 8 high-dose patients (20%) (P = 0.05). High-dose radiosurgery was associated with an increased rate of permanent trigeminal nerve dysfunction (54% versus 15%, P = 0.003). Bothersome dysesthesias occurred in 13 high-dose patients (32%), whereas only 1 low-dose patient had this complication (P = 0.01). Three high-dose patients (8%) developed corneal numbness after radiosurgery. Pain recurred with more frequency in patients not developing trigeminal nerve dysfunction after radiosurgery (9 of 22 patients, 41%) compared with those who sustained facial numbness, paresthesias, or dysesthesias (4 of 27 patients, 15%); however, the difference was not statistically significant (P = 0.08).

CONCLUSION

Higher doses of radiation may correlate with better facial pain outcomes after radiosurgery for trigeminal neuralgia. However, the incidence of significant trigeminal nerve dysfunction is markedly increased after radiosurgery for patients receiving high-dose radiosurgery. Because of the nonselective nature of this ablative technique, dose prescription should be limited to less than 90 Gy.
C1–C2 Transarticular Screw Fixation for Atlantoaxial Instability: A 6-year Experience
Authors: Haid Regis W. , Subach Brian R. , McLaughlin Mark R. , Rodts Gerald E. , Wahlig John B.
Published: July 2004

OBJECTIVE

We review a 6-year, single-center experience using the technique of C1–C2 transarticular screw fixation for atlantoaxial instability in 75 consecutive operations.

METHODS

The study group was composed of 43 men and 32 women, with a mean age of 44 years (range, 8–76 yr). Each patient had documented atlantoaxial instability. In 28 patients (37%), atlantoaxial instability was a result of trauma; in 22 patients, (29%), it was a result of rheumatoid arthritis; in 16 patients (21%), it was a result of prior surgery; and in 9 patients (12%), it was a result of congenital abnormalities. All patients underwent stabilization with C1–C2 transfacetal screws and a posterior interspinous construct. Nine patients had unilateral screws placed. Postoperatively, the patients were maintained in a rigid cervical orthosis for a mean of 11 weeks (range, 8–15 wk); five patients were immobilized with halo fixation for a mean of 13 weeks (range, 10–16 wk). The mean follow-up period was 2.4 years (range, 1–5.5 yr).

RESULTS

Osseous fusion was documented in 72 patients (96%). There were no hardware failures; however, three patients developed pseudarthrosis. Two superficial wound infections (one at the graft site and one at the cervical incision site) required antibiotic therapy. Four patients had transient suboccipital hypesthesia. No instances of an errant screw, dural laceration, or injury to the vertebral artery, spinal cord, or hypoglossal nerve were noted.

CONCLUSION

C1–C2 transarticular screw fixation supplemented with an interspinous construct yielded a 96% fusion rate, with a low incidence of complications. We attribute our successful outcomes to careful preoperative assessment and meticulous surgical technique.
Three-dimensional Visualization of the Pyramidal Tract in a Neuronavigation System during Brain Tumor Surgery: First Experiences and Technical Note
Authors: Coenen Volker A. , Krings Timo , Mayfrank Lothar , Polin Richard S. , Reinges Marcus H.T. , Thron Armin , Gilsbach Joachim M.
Published: July 2004

OBJECTIVE

To integrate spatial three-dimensional information concerning the pyramidal tracts into a customized system for frameless neuronavigation during brain tumor surgery.

METHODS

Four consecutive patients with intracranial tumors in eloquent areas underwent diffusion-weighted and anatomic magnetic resonance imaging studies within 48 hours before surgery. Diffusion-weighted datasets were merged with anatomic data for navigation purposes. The pyramidal tracts were segmented and reconstructed for three-dimensional visualization. The reconstruction results, together with the fused-image dataset, were available during surgery in the environment of a customized neuronavigation system.

RESULTS

In all four patients, the combination of reconstructed data and fused images was a helpful additional source of information concerning the tumor seat and topographical interaction with the pyramidal tract. In two patients, intraoperative motor cortex stimulation verified the tumor seat with regard to the precentral gyrus.

CONCLUSION

Diffusion-weighted magnetic resonance imaging allows individual estimation of large fiber tracts applicable as important information in intraoperative neuronavigation and in planning brain tumor resection. A three-dimensional representation of fibers associated with the pyramidal tract during brain tumor surgery is feasible with the presented technique and is a helpful adjunct for the neurosurgeon. The main drawbacks include the length of time required for the segmentation procedure, the lack of direct intraoperative control of the pyramidal tract position, and brain shift. However, mapping of large fiber tracts and its intraoperative use for neuronavigation have the potential to increase the safety of neurosurgical procedures and to reduce surgical morbidity.