bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neurophysiological Refinement of Subthalamic Nucleus Targeting
Authors: Sterio Djordje , Zonenshayn Martin , Mogilner Alon Y. , Rezai Ali R. , Kiprovski Kiril , Kelly Patrick J. , Beric Aleksandar 
Published: July 2004

ABSTRACT

OBJECTIVE
Advances in image-guided stereotactic surgery, microelectrode recording techniques, and stimulation technology have been the driving forces behind a resurgence in the use of functional neurosurgery for the treatment of movement disorders. Despite the dramatic effects of deep brain stimulation (DBS) techniques in ameliorating the symptoms of Parkinson's disease, many critical questions related to the targeting, effects, and mechanisms of action of DBS remain unanswered. In this report, we describe the methods used to localize the subthalamic nucleus (STN) and we present the characteristics of encountered cells.

METHODS
Twenty-six patients with idiopathic Parkinson's disease underwent simultaneous, bilateral, microelectrode-refined, DBS electrode implantation into the STN. Direct and indirect magnetic resonance imaging-based anatomic targeting was used. Cellular activity was analyzed for various neurophysiological parameters, including firing rates and interspike intervals. Physiological targeting confirmation was obtained by performing macrostimulation through the final DBS electrode.

RESULTS
The average microelectrode recording time for each trajectory was 20 minutes, with a mean of 5.2 trajectories/patient. Typical trajectories passed through the anterior thalamus, zona incerta/fields of Forel, STN, and substantia nigra-pars reticulata. Each structure exhibited a characteristic firing pattern. In particular, recordings from the STN exhibited an increase in background activity and an irregular firing pattern, with a mean rate of 47 Hz. The mean cell density was 5.6 cells/mm, with an average maximal trajectory length of 5.3 mm. Macrostimulation via the DBS electrode yielded mean sensory and motor thresholds of 4.2 and 5.7 V, respectively.

CONCLUSION
The principal objectives of microelectrode recording refinement of anatomic targeting are precise identification of the borders of the STN and thus determination of its maximal length. Microelectrode recording also allows identification of the longest and most lateral segment of the STN, which is our preferred target for STN DBS electrode implantation. Macrostimulation via the final DBS electrode is then used primarily to establish the side effect profile for postoperative stimulation. Microelectrode recording is a helpful targeting adjunct that will continue to facilitate our understanding of basal ganglion physiological features.
Elastance Correlates with Outcome after Endoscopic Third Ventriculostomy in Adults with Hydrocephalus Caused by Primary Aqueductal Stenosis
Authors: Tisell Magnus , Edsbagge Mikael , Stephensen Hannes , Czosnyka Marek , Wikkelsø Carsten 
Published: July 2004

ABSTRACTOBJECTIVETo study prospectively the correlation between clinical outcome after endoscopic third ventriculostomy (ETV) and resistance to the outflow of cerebrospinal fluid (Rout) and elastance in adults with hydrocephalus caused by primary aqueductal stenosis (AS).METHODSRout and elastance were measured in the subarachnoid space and intraventricularly before ETV in 15 consecutive patients. Three months after the ETV, the clinical effect was evaluated by standardized indices, and Rout and elastance were measured. If symptoms persisted and the ETV was patent, shunt surgery was offered. The effect of the shunt operation and Rout were measured after 3 months.RESULTSFour patients experienced excellent improvement, six improved slightly, and five had unchanged or deteriorated symptoms after ETV. Rout before ETV did not correlate with outcome. Rout decreased after ETV with correlation to the clinical effect; in the six patients who had shunt surgery, Rout decreased further. High preoperative elastance correlated strongly with a good outcome and reduction of ventricle size. Elastance did not change after ETV.CONCLUSIONRout intraventricularly and in the subarachnoid space could not predict the outcome of the ETV, but the reduction in Rout correlated positively with clinical improvement. Preoperative elastance correlated positively with clinical improvement, and elastance was unchanged after ETV. Clinical improvement correlated positively with reduction in ventricle size.
Inflammatory Mass Lesions Associated with Intrathecal Drug Infusion Catheters: Report and Observations on 41 Patients
Authors: Coffey Robert J. , Burchiel Kim 
Published: July 2004

ABSTRACT

OBJECTIVE
Several reports have described inflammatory mass lesions at the tip of intraspinal drug administration catheters. We evaluated the number of patients reported with this condition and whether data support hypotheses that have been put forth regarding the cause of these lesions.

METHODS
Information that was reported in the medical literature, and by Medtronic, Inc., to the United States Food and Drug Administration as of November 30, 2000, was reviewed.

RESULTS
Forty-one cases were identified, including 16 from the literature and 25 that were not published previously in the literature. Because of voluntary reporting and other methodological limitations, the actual number of cases must be higher than reported. All of the patients had chronic pain. The mean duration of therapy was 24.5 months. Most masses were located in the thoracic region. Intrathecal drugs included morphine or hydromorphone, either alone or mixed with other drugs, in 39 of 41 cases. No masses were reported in patients who received baclofen as the only intrathecal medication. Thirty patients underwent surgery to relieve spinal cord or cauda equina compression. Eleven patients were nonambulatory at last follow-up, and one died of a pulmonary embolus. Surgical specimens revealed noninfectious chronic inflammation, granuloma formation, and fibrosis or necrosis.

DISCUSSION
The most plausible hypothesis with regard to the cause of intrathecal catheter tip mass lesions implicates the administration of relatively high-concentration or high-dose opiate drugs or the use of drugs and admixtures that are not labeled for intrathecal use.

CONCLUSION
Patients who require high-dose intraspinal opioid therapy and those who receive drugs or admixtures that are not approved for intrathecal use should be monitored closely for signs of an extra-axial mass or catheter malfunction. Prompt diagnosis and treatment may preserve neurological function.
Adaptation of Cerebral Circulation to Brain Arteriovenous Malformations Increases Feeding Artery Pressure and Decreases Regional Hypotension
Authors: Quick Christopher M. , Leonard Edward F. , Young William L. 
Published: July 2004

ABSTRACT

PURPOSE
To determine how the adaptation of extranidal cerebral vessels affects feeding artery pressure, draining vein pressure, and regional hypotension due to the presence of brain arteriovenous malformations (BAVMs).

CONCEPT
BAVMs cause high flows in feeding arteries and draining veins and can induce profound hypotension in the neighboring vasculature. Despite the large difference in flow, endothelial shear stress (τ) observed in vessels ipsilateral to the BAVM is similar to τ in vessels contralateral to the BAVM, suggesting that the conductance vessels successfully adapt to keep τ constant. However, because BAVMs are discovered only after they are well developed, the natural history of the adaptation process in extranidal vessels is unknown.

RATIONALE
Currently, no way exists to determine experimentally the effects of adaptation of extranidal vessels in human patients. Therefore, a mathematical model of the cerebral vasculature is used to study adaptation in response to BAVMs. By comparing pressures and flows calculated before and after adaptation, the effect of adaptation of the conductance vessels on regional hemodynamics can be evaluated.

DISCUSSION
Structural adaptation of the extranidal circulation seems not only to reset τ, but also to ameliorate regional hypotension induced by BAVMs. However, this compensatory mechanism also increases feeding artery pressure and thus may increase the risk of hemorrhagic stroke.
Endovascular Administration after Intravenous Infusion of Thrombolytic Agents for the Treatment of Patients with Acute Ischemic Strokes
Authors: Suarez Jose I. , Zaidat Osama O. , Sunshine Jeffrey L. , Tarr Robert , Selman Warren R. , Landis Dennis M.D. 
Published: July 2004

ABSTRACT

OBJECTIVE
To determine the feasibility of combined intravenous and intra-arterial thrombolytic therapy for acute ischemic strokes and to evaluate its associated risks, using magnetic resonance imaging as a triage tool. Intravenous treatment followed by intra-arterial infusion may increase the rate of recanalization and lead to better clinical results, with reduced frequency of intracranial hemorrhage.

METHODS
Our Brain Attack Team evaluated patients who presented within 3 hours after symptom onset. Patients who did not demonstrate improvement and exhibited no evidence of intracranial hemorrhage on head computed tomographic scans were treated with intravenously administered recombinant tissue plasminogen activator (0.6 mg/kg) and underwent emergency magnetic resonance imaging of the head. T2-weighted turbo-gradient and spin echo and echo-planar diffusion- and perfusion-weighted imaging scans were obtained. Patients with evidence of imaging abnormalities indicating acute cortical infarction underwent cerebral angiography. After determination of vessel occlusion, intra-arterially administered urokinase (up to 750,000 units) or intra-arterially administered recombinant tissue plasminogen activator (maximal dose, 0.3 mg/kg) was used to achieve recanalization.

RESULTS
We treated 45 patients with this protocol. The mean age was 67 ± 13 years, and 58% of the patients were women. There was a significant improvement in National Institutes of Health Stroke Scale scores after treatment. There was good correlation between abnormal perfusion-weighted imaging findings and cerebral angiographic findings (complete vessel occlusion). The incidence of symptomatic intracranial hemorrhage was 4.4% in this cohort. Seven patients died in the hospital, and the majority of survivors (77%) experienced good outcomes (Barthel index of ≥95) 3 months after treatment.

CONCLUSION
Our data demonstrate that this protocol is feasible and that combined intravenous and intra-arterial thrombolysis to treat acute ischemic strokes is sufficiently safe to warrant further evaluation.
Somatotopy of the Supplementary Motor Area: Evidence from Correlation of the Extent of Surgical Resection with the Clinical Patterns of Deficit
Authors: Fontaine Denys , Capelle Laurent , Duffau Hugues 
Published: July 2004

ABSTRACT

OBJECTIVE
This study, which aimed to confirm or invalidate the somatotopic organization of the supplementary motor area (SMA), correlates the pattern of clinical symptoms observed after SMA removal with the extent of resection.

METHODS
Eleven patients with medial precentral glioma underwent partial or complete tumoral resection of the SMA. Seven patients underwent preoperative functional magnetic resonance imaging that incorporated speech and motor tasks. During the operation, the primary motor and speech areas and pathways (in the dominant side) were identified by use of intraoperative direct cortical or subcortical stimulation, and these areas were respected.

RESULTS
SMA resection resulted in motor deficits, language deficits, or both; the deficits were always regressive, and they corresponded to the SMA syndrome. The topography and severity of these deficits were correlated to the extent of the SMA resection. The location of the deficit corresponded to SMA somatotopy: the representations of the lower limb, the upper limb, the face, and language (in the left-dominant SMA) were located from posterior to anterior. This somatotopy was also observed with functional magnetic resonance imaging.

CONCLUSION
Correlation between clinical patterns of deficit and the extent of SMA resection, guided by means of pre- and intraoperative functional methods, provides strong arguments in favor of somatotopy in this area. This knowledge should allow clinicians to base preoperative predictions of the pattern of postsurgical deficit and recovery on the planned resection, thus allowing them to inform patients accurately before the procedure.
Biportal Thoracoscopic Sympathectomy: Surgical Techniques and Clinical Results for the Treatment of Hyperhidrosis
Authors: Han Patrick P. , Gottfried Oren N. , Kenny Kathy J. , Dickman Curtis A. 
Published: July 2004

ABSTRACT

OBJECTIVE
To describe a bilateral thoracoscopic sympathectomy procedure, using a biportal approach, for the treatment of severe hyperhidrosis.

METHODS
Between May 1996 and September 2000, 103 consecutive patients underwent thoracoscopic sympathectomy procedures to treat bilateral hyperhidrosis (206 procedures). Operative results, complications, and patient satisfaction were determined by reviews of hospital and office charts and by follow-up assessments in the outpatient clinic. Long-term results were determined with clinical examinations, follow-up office visits, and follow-up questionnaires.

RESULTS
Ninety-three patients presented with primary palmar hyperhidrosis, eight with primary axillary hyperhidrosis, and two with primary craniofacial hyperhidrosis. Rates of complete resolution in the primary area affected were 100% in palmar and craniofacial cases and 75% in axillary cases. The average length of hospitalization was 1.06 days, and 96 patients (93.2%) were discharged on or before the end of the first postoperative day. Of 59 patients (57.3%) who developed compensatory hyperhidrosis, only 11 patients (10.7%) reported that it was bothersome and none considered it disabling. All postoperative complications were transient; five patients experienced unilateral Horner's syndrome, three patients experienced intercostal neuralgia, and two patients required a chest tube after surgery because of a pneumothorax.

CONCLUSION
Thoracoscopic sympathectomy using a biportal approach effectively treats hyperhidrosis and is associated with short hospital stays, high patient satisfaction rates, and low rates of compensatory hyperhidrosis or other complications.
Somatotopic Organization of the Facial Nucleus Is Disrupted after Lesioning and Regeneration of the Facial Nerve: The Histological Representation of Synkinesis
Authors: Choi David , Raisman Geoffrey 
Published: July 2004

ABSTRACTOBJECTIVEAfter facial nerve repair, involuntary movement of part of the face during voluntary movement of another part of the face is common. We describe an animal model of facial nerve lesion, repair, and regeneration that demonstrates abnormal organization of the facial nucleus; this model may be used to study synkinesis.METHODSIn 18 rats, the facial nerve was cut completely, proximal to the parotid gland, and immediately sutured end-to-end. After a period of regeneration of 1 to 10 months, retrograde fluorescence labeling of the distal branches of the facial nerve was performed. The distribution of the tracers in the facial nucleus was assessed in both the lesioned animals and in a nonlesioned group (n = 20).RESULTSIn the control animals, muscle groups were somatotopically represented in the facial nucleus. After lesioning, repair, and regeneration, the somatotopy of the facial nucleus was disrupted. Axons projected from the facial nucleus to incorrect peripheral muscle groups, and aberrant branches were observed to simultaneously innervate different subdivisions of the facial nerve. The numbers of aberrant axons and branches did not change significantly during periods of regeneration ranging from 1 to 10 months.CONCLUSIONOur model provides a clear demonstration of the failure of adult facial nerve axons to make correct connections with their distal targets during regeneration. This model may be used to assess strategies aimed at minimizing synkinesis and, by assessing histology together with behavior, provides a more robust model than those previously described.
Chondromyxoid Fibroma of the Cervical Spine: Case Report
Authors: Lopez-Ben Robert , Siegal Gene P. , Hadley Mark N. 
Published: July 2004

ABSTRACT

OBJECTIVE AND IMPORTANCE
The clinical, pathological, and imaging findings in a patient with a chondromyxoid fibroma involving the C2 vertebra are reported. Seven cases that involve the cervical spine have previously been reported in the literature; the posterior vertebral body and posterior elements are the most frequently involved. To our knowledge, this is the first reported case of C2 involvement and craniocervical instability.

CLINICAL PRESENTATION
A 20-year-old man presented with intermittent neck pain resulting from a fall 4 years earlier. X-rays and magnetic resonance imaging demonstrated a lytic lesion in the body of C2, as well as instability at C1–C2.

INTERVENTION
Preoperative transcatheter angiography and embolization were performed. An expansile tumor of the C2 vertebral body was resected via a transoral approach. Because of craniocervical instability, fusion from the occiput to posterior elements of C1 through C4 was performed.

CONCLUSION
Chondromyxoid fibroma is a rare benign bone tumor that is uncommonly found in the spine and may mimic other lesions, particularly radiographically. We report the first known involvement of C2 by this tumor in the modern English-language literature. The patient has had excellent clinical and radiographic resolution of the prior instability with no neck pain, instability, or local recurrence.
C1–C2 Pedicle Screw Fixation with Rigid Cantilever Beam Construct: Case Report and Technical Note
Authors: Resnick Daniel K. , Benzel Edward C. 
Published: July 2004

ABSTRACT

OBJECTIVE AND IMPORTANCE
Transarticular screw fixation of the C1–C2 complex provides immediate rigid fixation of the unstable spine. The technique is not feasible in a certain proportion of patients because of the position of the vertebral artery or the patient's body habitus.

CLINICAL PRESENTATION
The authors describe a rigid screw technique for the surgical treatment of a woman who was excluded as a candidate for C1–C2 transarticular screw fixation.

TECHNIQUE
C1–C2 pedicle screw fixation was achieved using a fixed moment arm cantilever beam system. This system provided immediate rigid fixation of the C1–C2 complex in a patient who was not a candidate for transarticular screw fixation.

CONCLUSION
This technique is technically more forgiving than posterior transarticular screw fixation and may be applied to a broader spectrum of patients.
Nonvestibular Schwannomas of the Brain: A 7-Year Experience
Authors: Sarma Sajjan , Sekhar Laligam N. , Schessel David A. 
Published: July 2004

Abstract

OBJECTIVE:
Nonvestibular schwannomas are uncommon tumors of the brain. Trigeminal nerve schwannomas are the most common of this group, followed by glossopharyngeal, vagal, facial, accessory, hypoglossal, oculomotor, trochlear, and abducens nerve schwannomas, in descending order of frequency. We present a series of nonvestibular schwannomas that were surgically treated during a 7-year period.

METHODS:
Forty-six patients with schwannomas of Cranial Nerves V (26 cases), VII (7 cases), IX, X, and XI (9 cases), XII (3 cases), and III (1 case) were microsurgically treated by the senior author (LNS) during a 7-year period, from 1993 to 2000. The clinical presentations, operative approaches, complications, and results were studied.

RESULTS:
Forty-five patients underwent gross total tumor resection in the first operation. One patient who had undergone subtotal tumor resection in the initial operation experienced a large recurrence after 4 years, and gross total tumor resection was achieved in the second operation. There were no postoperative deaths. Postoperative morbidity consisted of cerebrospinal fluid leaks for 5 patients (3 patients required a second operation to repair the leak, and 2 patients responded to lumbar drain placement), meningitis for 3 patients (2 cases were aseptic and 1 involved bacterial meningitis, which resolved with antibiotic therapy), vasospasm requiring angioplasty for 1 patient, temporary hemiparesis for 2 patients (who experienced good recoveries), and permanent hemiparesis for 1 patient. New cranial nerve deficits were observed for 24% of patients but were usually partial. The mean follow-up period was 33.3 months (range, 0.2–93 mo). No patient experienced tumor recurrence after complete tumor removal. The patient who experienced regrowth of the tumor did not exhibit recurrence after the second operation. The Karnofsky Performance Scale scores at the latest follow-up examination were 80 or more for 45 patients (98%) and 70 for 1 patient.

CONCLUSION:
Nonvestibular schwannomas can be treated via microsurgical excision, with excellent functional results. Recurrence is rare after total tumor excision, although much longer follow-up monitoring is required.
Tuberculoma of the Conus Medullaris: Case Report
Authors: Türeyen Kudret 
Published: July 2004

Abstract

OBJECTIVE AND IMPORTANCE:
Intramedullary spinal tuberculoma is a rare form of central nervous system tuberculosis. This article describes an affected patient who presented with left leg paresis.

CLINICAL PRESENTATION:
A 46-year-old man presented with a 7-day history of left leg weakness. The patient's medical history included infection with pulmonary tuberculosis 15 years previously, at which time he had been treated with antituberculosis therapy. The neurological examination performed at admission revealed left leg paresis with Grade 2/5 power in all muscle groups. The patient reported no urinary or bowel problems.

INTERVENTION:
Surgery was performed with the patient in the prone position. The procedure involved laminectomies at T11, T12, and L1, followed by a midline myelotomy. The mass was excised completely. Histopathological examination revealed a granulomatous lesion that contained Langhans' giant cells, inflammatory cells, and evidence of caseating necrosis. The patient was prescribed a 6-month course of antituberculosis therapy with pyrazinamide, isoniazid, and rifampin.

CONCLUSION:
The outcome was favorable. Recently, a number of authors have reported success with medical management of intraspinal tuberculoma. Intraspinal tuberculoma produces a mass effect that can jeopardize spinal cord function. The optimal treatment is a combination of microsurgical resection and antituberculosis chemotherapy.