bluuebunny/crossref_metadata_2025 huggingface dataset:
Endoscopically aided retroperitoneal placement of a lumboperitoneal shunt
Authors: Kubo Shigeki , Ueno Masato , Takimoto Hiroshi , Karasawa Jun , Kato Amami , Yoshimine Toshiki
Published: May 2009

✓ The authors developed a method for retroperitoneal placement of a lumboperitoneal (LP) shunt with the aid of endoscopic monitoring. To perform this procedure, the patient is positioned laterally, the retroperitoneum is entered and dilated with a balloon through a small incision in the flank, and the space is maintained with CO2 insufflation. A peritoneal catheter is introduced into the cavity from the lumbar incision, through which the spinal catheter has been inserted. With the aid of a percutaneous nephroscope inserted in the cavity, the peritoneum is opened with endoscopically guided forceps through the manipulation channel. The shunt tube is then inserted into the pelvic peritoneum with the same forceps. Only two small skin incisions are needed for this method, and the shunt system is shorter compared with the conventional LP setup, which may lessen the risk of obstruction. This method is advantageous in patients who have undergone previous abdominal surgery, because it provides access to the peritoneum without concern for the presence of peritoneal adhesions.
Use of the peak troponin value to differentiate myocardial infarction from reversible neurogenic left ventricular dysfunction associated with aneurysmal subarachnoid hemorrhage
Authors: Bulsara Ketan R. , McGirt Matthew J. , Liao Lawrence , Villavicencio Alan T. , Borel Cecil , Alexander Michael J. , Friedman Allan H.
Published: May 2009

Object. Differentiating myocardial infarction (MI) from reversible neurogenic left ventricular dysfunction (stunned myocardium [SM]) associated with aneurysmal subarachnoid hemorrhage (SAH) is critical for early surgical intervention. The authors hypothesized that the cardiac troponin (cTn) trend and/or echocardiogram could be used to differentiate between the two entities.

Methods. A retrospective study was conducted for the period between 1995 and 2000. All patients included in the study met the following criteria: 1) no history of cardiac problems; 2) new onset of abnormal cardiac function (ejection fraction [EF] < 40% on echocardiograms); 3) serial cardiac markers (cTn and creatine kinase MB isoform [CK-MB]); 4) surgical intervention for their aneurysm; and 5) cardiac output monitoring either by repeated echocardiograms or invasive hemodynamic monitoring during the first 4 days post-SAH when the patients were euvolemic.

Of the 350 patients with SAH, 10 (2.9%) had severe cardiac dysfunction. Of those 10, six were women and four were men. The patients' mean age was 53.5 years (range 29–75 years) and their SAH was classified as Hunt and Hess Grade III or IV. Aneurysm distribution was as follows: basilar artery tip (four); anterior communicating artery (two); middle cerebral artery (one); posterior communicating artery (two); and posterior inferior cerebellar artery (one). The mean EF at onset was 33%. The changes on echocardiograms in these patients did not match the findings on electrocardiograms (EKGs). Within 4.5 days, dramatic improvement was seen in cardiac output (from 4.93 ± 1.16 L/minute to 7.74 ± 0.88 L/minute). Compared with historical controls in whom there were similar levels of left ventricular dysfunction after MI, there was no difference in peak CK-MB. A 10-fold difference, however, was noted in cTn values (0.22 ± 0.25 ng/ml; control 2.8 ng/ml; p < 0.001).

Conclusions. The authors determined the following: 1) that the CK-MB trend does not allow differentiation between SM and MI; 2) that echocardiograms revealing significant inconsistencies with EKGs are indicative of SM; and 3) that cTn values less than 2.8 ng/ml in patients with EFs less than 40% are consistent with SM.
Comparison between perimesencephalic nonaneurysmal subarachnoid hemorrhage and subarachnoid hemorrhage caused by posterior circulation aneurysms
Authors: Alén Jose F. , Lagares Alfonso , Lobato Ramiro D. , Gómez Pedro A. , Rivas Juan J. , Ramos Ana
Published: May 2009

Object. Some authors have questioned the need to perform cerebral angiography in patients presenting with a benign clinical picture and a perimesencephalic pattern of subarachnoid hemorrhage (SAH) on initial computerized tomography (CT) scans, because the low probability of finding an aneurysm does not justify exposing patients to the risks of angiography. It has been stated, however, that ruptured posterior circulation aneurysms may present with a perimesencephalic SAH pattern in up to 10% of cases. The aim of the present study was twofold: to define the frequency of the perimesencephalic SAH pattern in the setting of ruptured posterior fossa aneurysms, and to determine whether this clinical syndrome and pattern of bleeding could be reliably and definitely distinguished from that of aneurysmal SAH.

Methods. Twenty-eight patients with ruptured posterior circulation aneurysms and 44 with nonaneurysmal perimesencephalic SAH were selected from a series of 408 consecutive patients with spontaneous SAH admitted to the authors' institution. The admission unenhanced CT scans were evaluated by a neuroradiologist in a blinded fashion and classified as revealing a perimesencephalic SAH or a nonperimesencephalic pattern of bleeding.

Of the 28 patients with posterior circulation aneurysms, five whose grade was I according to the World Federation of Neurosurgical Societies scale were classified as having a perimesencephalic SAH pattern on the initial CT scan. The data show that the likelihood of finding an aneurysm on angiographic studies obtained in a patient with a perimesencephalic SAH pattern is 8.9%. Conversely, ruptured aneurysms of the posterior circulation present with an early perimesencephalic SAH pattern in 16.6% of cases.

Conclusions. This study supports the impression that there is no completely sensitive and specific CT pattern for a nonaneurysmal SAH. In addition, the authors believe that there is no specific clinical syndrome that can differentiate patients who have a perimesencephalic SAH pattern caused by an aneurysm from those without aneurysms. Digital subtraction angiography continues to be the gold standard for the diagnosis of cerebral aneurysms and should be performed even in patients who have the characteristic perimesencephalic SAH pattern on admission CT scans.
Effects of the Ca++-permeable nonselective cation channel blocker LOE 908 on subarachnoid hemorrhage—induced vasospasm in the basilar artery in rabbits
Authors: Kawanabe Yoshifumi , Masaki Tomoh , Hashimoto Nobuo
Published: May 2009

Object. The Ca++ influx into vascular smooth-muscle cells (VSMCs) plays a fundamental role in the development and chronic effects of vasospasm after subarachnoid hemorrhage (SAH). The Ca++-permeable nonselective cation channels (NSCCs) are activated by several endothelium-derived constricting factors such as endothelin 1 (ET-1) and thromboxane A2. Moreover, the receptor-operated Ca++ channel blocker LOE 908 inhibits ET-1—induced extracellular Ca++ influx via NSCCs in the VSMCs of the basilar artery (BA) and the NSCC-dependent part of ET-1—induced vasoconstriction of BA rings. The purpose of the present study was to evaluate the in vivo role of LOE 908 on SAH-induced vasospasm.

Methods. Forty-two Japanese white rabbits were assigned to seven groups. Treatment groups consisted of the following: 1) control rabbits without SAH that received a cisternal injection of saline; 2) rabbits with SAH that were subjected to the intravenous administration of saline; 3 through 6) rabbits with SAH that underwent the intravenous administration of 0.01, 0.1, 1, or 10 mg/kg LOE 908, respectively; and 7) rabbits without SAH that underwent the intravenous administration of 10 mg/kg LOE 908. Autologous blood was injected into the cisterna magna. The caliber of the BA was measured on angiographic studies before and after the cisternal injection of autologous blood.

The intravenous injection of LOE 908 inhibited the magnitude of an SAH-induced vasosapsm. In addition, the concentration of LOE 908 required to relax vasospasm (1 mg/kg) correlated with that required to block Ca++ influx into VSMCs.

Conclusions. The Ca++ channel blocker LOE 908 may inhibit the magnitude of an SAH-induced vasospasm by blocking the influx of Ca++ through NSCCs in rabbit BAs. Blocking the NSCCs may represent a new treatment for cerebral vasospasm after SAH.
Stretching and breaking characteristics of cerebrospinal fluid shunt tubing
Authors: Tomes Daniel J. , Hellbusch Leslie C. , Alberts L. Russell
Published: May 2009

Object. Cerebrospinal fluid (CSF) shunt system malfunction due to silastic tubing fracture necessitates revision surgery in shunt-dependent individuals. The goal of this study was to examine the mechanical stretching and breaking characteristics of new and used CSF shunt tubing catheters to determine if any inherent physical properties predispose the tubing to fracture.

Methods. Fifty-millimeter segments of new and retrieved (used) CSF shunt tubing were stretched to 120 mm in a hydraulic press to determine modulus values (modulus = stress/strain) and to measure permanent tubing deformation imparted by the applied stress and strain. Similar 50-mm tubing segments were also stretched in an electromechanical material testing system until fracture occurred; the force and strain needed to break the tubing was recorded at the time of failure. The results demonstrate that shunt tubing with a greater cross-sectional area requires greater force to fracture, and that catheters become weaker the longer they are implanted. Barium-impregnated shunt tubing, compared with translucent tubing, appears to require less applied stress and strain to break and may fracture more easily in vivo. The variety of modulus values obtained for the new catheters tested indicates that the various companies may be using materials of different quality in tubing manufacture.

Conclusions. A CSF shunt catheter design that incorporates tubing with a greater cross-sectional area may lead to fewer fractures of indwelling catheters and a reduction in shunt revision surgery.
Experimental appraisal of the lack of antitumor natural killer cell—mediated immunosurveillance in response to lymphomas growing in the mouse brain
Authors: Yamasaki Toshiki , Moritake Kouzo , Klein George
Published: May 2009

Object. Natural killer (NK) cell—mediated immunosurveillance in the brain is currently obscure, in contrast with the intracerebral immune reaction of cytotoxic T lymphocytes (CTLs) to tumor cells. The goal of this study, in which a controlled tumor model was used, was to investigate a relationship between NK cells and major histocompatibility complex (MHC) Class I gene expression in intracerebral tumor—bearing hosts.

Methods. A matched set of two cloned tumor cell lines (lymphoma+ and lymphoma−), which differ only in MHC Class I gene expression, was established from the parental YAC-1 cell line (a target widely accepted as being sensitive to murine NK cells). An in vivo rapid elimination assay (REA) was performed using tumor cells labeled with [125I] 5-iodo-2-deoxyuridine to evaluate intracerebral NK cell—mediated defense immunity. There was no difference in the in vitro growth rate and c-myc gene expression between lymphoma+ and lymphoma− cells. An in vitro cytotoxicity assay showed that the lymphoma+ cell line was sensitive to MHC Class I—restricted CTL-mediated lysis, whereas the lymphoma− line was refractory to it. Both were susceptible to NK cell—mediated lysis, comparable to the level shown by YAC-1 cells. Flow cytometry revealed that lymphoma+ reacted positively for cell-surface MHC Class I molecules, whereas lymphoma− had no reaction. Four- to 72-hour REAs, performed using either cell line, disclosed no clearance of radiolabeled tumor cells from the brain in independent groups of untreated and T cell—depleted mice; this contrasted with eradication of radioactivity from the lungs. In NK cell—depleted mice, however, there was no elimination of radiolabeled tumor cells from the brain or lungs. The MHC Class I expression on lymphoma+ cells was enhanced after intracerebral inoculation, rendering them less sensitive to NK cells. By contrast, lymphoma− cells remained negative for cell-surface MHC expression, being sensitive to NK cells and refractory to CTLs after intracerebral inoculation. These results indicate the absence of NK cell—mediated lytic activity in the brain. This allows even NK cell—sensitive tumor cells to escape intracerebral immunosurveillance.

Conclusions. These experiments have refined the information that the brain may lack NK cell—mediated defense immunity against intracerebrally growing tumors, representing a characteristic aspect of this immunologically privileged organ.
Subclinoid aneurysms
Authors: Nutik Stephen L.
Published: May 2009

Object. This study was undertaken to analyze the features that define subclinoid aneurysms.

Methods. Five cases of laterally directed carotid artery (CA) aneurysms adjacent to the anterior clinoid process (ACP) were identified in a series of approximately 1400 surgically treated aneurysms. These cases were selected because the aneurysms had the same features as the only previously described “subclinoid” aneurysm. The angiographic and anatomical features of the five cases were analyzed.

Conclusions. Subclinoid aneurysms are a unique group of congenital berry aneurysms. They originate from the lateral surface of the CA adjacent to the ACP. They are partially or completely hidden from view at surgery by the ACP and are partially or completely proximal to the distal dural ring of the CA. The proximal neck of these lesions is located at the same level of the CA cut perpendicular to its axis of blood flow as the origin of the ophthalmic artery (OphA), but they do not originate at that or any other branch of the CA. They can only be definitively differentiated from OphA, anterior paraclinoid, and blister-like aneurysms at surgery.
Long-term seizure outcomes following amygdalohippocampectomy
Authors: Wieser H. Gregor , Ortega Marcos , Friedman Alon , Yonekawa Yasuhiro
Published: May 2009

Object. Analyses of the results of surgery for epilepsy are hindered by inconsistent classifications of seizure outcome, small numbers of patients, and short postoperative follow-up periods. The authors conducted a retrospective study with a reassessment of the long-term seizure outcomes in patients who underwent selective amygdalohippocampectomy (SelAH) for pharmacotherapy—resistant mesial temporal lobe epilepsy (MTLE) at the Zurich University Hospital from 1975 to 1999.

Methods. Year-by-year data and the last available data on seizure outcomes were retrospectively assessed for 369 consecutively surgically treated patients who had participated in a follow-up period longer than 1 year as of 1999 and whose outcomes were classified according to the Engel scale and the proposed new International League Against Epilepsy (ILAE) scale. Patients were grouped into nonlesional and lesional MTLE groups depending on whether they harbored a gross anatomical lesion that caused the MTLE. Differentiation was made between curative and palliative operations. Complications related to surgery are reported for 453 patients who underwent SelAH and participated in more than 3 months of follow-up review.

The last available outcome data according to the Engel scale were found to be generally similar to those of the new ILAE classification, with 66.9% of patients free from disabling seizures (Engel Class I) compared with 57.1% who were completely seizure and aura free (ILAE Class 1). The last available data on seizure outcome were not significantly different between patients in the lesional and nonlesional MTLE groups. In the lesional group, seizure outcomes were significantly better when patients underwent surgery early in the course of the disease. Overall, 70% of the patients received reductions in their antiepileptic drug treatment at the time of the last available follow-up review. Complications related to the surgical procedures were rare.

Conclusions. The authors conclude that SelAH is a safe and effective surgical procedure for MTLE.
Usefulness of intraoperative electrical subcortical mapping during surgery for low-grade gliomas located within eloquent brain regions: functional results in a consecutive series of 103 patients
Authors: Duffau Hugues , Capelle Laurent , Denvil Dominique , Sichez Nicole , Gatignol Peggy , Taillandier Luc , Lopes Manuel , Mitchell Mary-Christine , Roche Sabine , Muller Jean-Charles , Bitar Ahmad , Sichez Jean-Pierre , van Effenterre Rémy
Published: May 2009

Object. Although a growing number of authors currently advocate surgery to treat low-grade gliomas, controversy still persists, especially because of the risk of inducing neurological sequelae when the tumor is located within eloquent brain areas. Many researchers performing preoperative neurofunctional imaging and intraoperative electrophysiological methods have recently reported on the usefulness of cortical functional mapping. Despite the frequent involvement of subcortical structures by these gliomas, very few investigators have specifically raised the subject of fiber tracking. The authors in this report describe the importance of mapping cortical and subcortical functional regions by using intraoperative realtime direct electrical stimulations during resection of low-grade gliomas.

Methods. Between 1996 and 2001, 103 patients harboring a corticosubcortical low-grade glioma in an eloquent area, with no or only mild deficit, had undergone surgery during which intraoperative electrical mapping of functional cortical sites and subcortical pathways was performed throughout the procedure.

Both eloquent cortical areas and corresponding white fibers were systematically detected and preserved, thus defining the resection boundaries. Despite an 80% rate of immediate postoperative neurological worsening, 94% of patients recovered their preoperative status within 3 months—10% even improved—and then returned to a normal socioprofessional life. Eighty percent of resections were classified as total or subtotal based on control magnetic resonance images.

Conclusions. The use of functional mapping of the white matter together with cortical mapping allowed the authors to optimize the benefit/risk ratio of surgery of low-grade glioma invading eloquent regions. Given that preoperative fiber tracking with the aid of neuroimaging is not yet validated, we used intraoperative real-time cortical and subcortical stimulations as a valuable adjunct to the other mapping methods.
Radiation exposure of normal temporal bone structures during stereotactically guided gamma knife surgery for vestibular schwannomas
Authors: Linskey Mark E. , Johnstone Peter A. S. , O'Leary Michael , Goetsch Steven
Published: May 2009

Object. The dosimetry of radiation exposure of healthy inner, middle, and external ear structures that leads to hearing loss, tinnitus, facial weakness, dizziness, vertigo, and imbalance after gamma knife surgery (GKS) for vestibular schwannomas (VSs) is unknown. The authors quantified the dose of radiation received by these structures after GKS for VS to assess the likelihood that these doses contributed to postradiosurgery complications.

Methods. A retrospective study was performed using a prospectively acquired database of a consecutive series of 54 patients with VS who were treated with GKS during a 3.5-year period at an “open unit” gamma knife center. Point doses were measured for 18 healthy temporal bone structures in each patient, with the anatomical position of each sampling point confirmed by a fellowship-trained neurootologist. These values were compared against single-dose equivalents for the 5-year tolerance dose for a 5% risk of complications and the 5-year tolerance dose for a 50% risk of complications, which were calculated using known 2-Gy/fraction thresholds for chronic otitis, chondromalacia, and osseous necrosis, as well as the tumor margin dose and typical tumor margin prescription doses for patients in whom hearing preservation was attempted.

External and middle ear doses were uniformly low. The intratemporal facial nerve is susceptible to unintentionally high radiation exposure at the fundus of the internal auditory canal, with higher than tumor margin doses detected in 26% of cases. In the cochlea, the basal turn near the modiolus and its inferior portion are most susceptible, with doses greater than 12 Gy detected in 10.8 and 14.8% of cases. In the vestibular labyrinth, the ampulated ends of the lateral and posterior semicircular canals are most susceptible, with doses greater than 12 Gy detected in 7.4 and 5.1% of cases.

Conclusions. Doses delivered to middle and external ear structures are unlikely to contribute to post-GKS complications, but unexpectedly high doses may be delivered to sensitive areas of the intratemporal facial nerve and inner ear. Unintentional delivery of high doses to the stria vascularis, the sensory neuroepithelium of the inner ear organs and/or their ganglia, may play a role in the development of post-GKS tinnitus, hearing loss, dizziness, vertigo, and imbalance. Minimizing treatment complications post-GKS for VS requires precise dose planning conformality with the three-dimensional surface of the tumor.
Multislice computerized tomography angiography in the evaluation of intracranial aneurysms: a comparison with intraarterial digital subtraction angiography
Authors: Wintermark Max , Uske Antoine , Chalaron Marc , Regli Luca , Maeder Philippe , Meuli Reto , Schnyder Pierre , Binaghi Stefano
Published: May 2009

Object. The goal of this study was to assess the diagnostic accuracy of computerized tomography (CT) angiography performed with the aid of multislice technology (MSCT angiography) in the investigation of intracranial aneurysms, by comparing this method with intraarterial digital subtraction (IADS) angiography.

Methods. Fifty consecutive adult patients, who successively underwent MSCT angiography (four rows) and IADS angiography of intracranial vessels, were prospectively identified. The MSCT angiography studies consisted of 1.25-mm slices, with 0.8-mm reconstruction intervals, a pitch of 0.75, and timing determined by a test bolus. Two neuroradiologists, who were blinded to the initial interpretation of the MSCT angiograms as well as to those of the IADS angiograms, independently reviewed the MSCT angiograms for the detection and characterization of intracranial aneurysms.

Forty-nine intracranial aneurysms were identified in 40 patients; 33 of these lesions were responsible for subarachnoid hemorrhage. The sensitivity, specificity, and accuracy of MSCT angiography in the detection of intracranial aneurysms were 94.8, 95.2, and 94.9%, respectively, on a per-aneurysm basis and 99, 95.2, and 98.3%, respectively, on a per-patient basis. Interobserver agreement was 98%. There was an excellent correlation between aneurysm size assessed using MSCT angiography and that determined by IADS angiography (slope = 0.916, r = 0.877, p < 0.001); however, 2 mm stood as the cutoff size below which the sensitivity of MSCT angiography was statistically lower. That method displayed great accuracy in characterizing the morphological characteristics of the aneurysm.

Conclusions. Multislice CT angiography is an accurate and robust noninvasive screening test for intracranial aneurysms. It performs better than that reported for single-slice CT angiography. Introduction of eight- and especially 16-row MSCT angiography will provide further progression through thinner slices, a lower pitch, and a purely arterial phase.
Guglielmi Detachable Coil embolization of cerebral aneurysms: 11 years' experience
Authors: Murayama Yuichi , Nien Yih Lin , Duckwiler Gary , Gobin Y. Pierre , Jahan Reza , Frazee John , Martin Neil , Viñuela Fernando
Published: May 2009

Object. The authors report on their 11 years' experience with embolization of cerebral aneurysms using Guglielmi Detachable Coil (GDC) technology and on the attendant anatomical and clinical outcomes.

Methods. Since December 1990, 818 patients harboring 916 aneurysms were treated with GDC embolization at University of California at Los Angeles Medical Center. For comparative purposes, the patients were divided into two groups: Group A included their initial 5 years' experience with 230 patients harboring 251 aneurysms and Group B included the later 6 years' experience with 588 patients harboring 665 aneurysms.

Angiographically demonstrated complete occlusion was achieved in 55% of aneurysms and a neck remnant was displayed in 35.4% of lesions. Incomplete embolization was performed in 3.5% of aneurysms, and in 5% occlusion was attempted unsuccessfully. A comparison between the two groups revealed a higher complete embolization rate in patients in Group B compared with that in Group A patients (56.8 and 50.2%, respectively). The overall morbidity/mortality rate was 9.4%.

Angiographic follow ups were obtained in 53.4% of cases of aneurysms, and recanalization was exhibited in 26.1% of aneurysms in Group A and 17.2% of those in Group B. The overall recanalization rate was 20.9%. Note that recanalization was related to the size of the dome and neck of the aneurysm.

Overall incidence of delayed aneurysm rupture was 1.6%, a rate that improved in the past 5 years to 0.5%. Ten of 12 delayed ruptures occurred in large or giant aneurysms.

Conclusions. The clinical and postembolization outcomes in patients treated with the GDC system have improved in the past 5 years. Aneurysm recanalization, however, is still a major limitation of current GDC therapy. Follow-up angiography is mandatory after GDC embolization of cerebral aneurysms. Further technical and device improvements are mandatory to overcome current GDC limitations.
Transsphenoidal microsurgical treatment of Cushing disease: postoperative assessment of surgical efficacy by application of an overnight low-dose dexamethasone suppression test
Authors: Chen Joseph C. T. , Amar Arun P. , Choi SooHo , Singer Peter , Couldwell William T. , Weiss Martin H.
Published: May 2009

Object. Transsphenoidal adenomectomy with resection of a defined pituitary adenoma has been the treatment of choice for CD for the last 30 years. Surgical resection, however, may not always result in long-term remission of CD. This is particularly important in light of the high risk of morbidity and mortality in patients in the unsuccessfully treated cushingoid state. As such, it is interesting to identify prognostic factors that may predict the likelihood of long-term remission.

Methods. The authors review their series of 174 patients who have undergone transsphenoidal procedures for CD over a period of 20 years with minimum follow-up periods of 5 years. Selection of these patients was based on clinical, imaging, and laboratory criteria that included serum cortisol levels, loss of diurnal variation in serum cortisol levels, urinary free cortisol concentration, and results of a dexamethasone suppression test, petrosal sinus sampling, and corticotroph-releasing hormone stimulation tests as indicated. All patients who met the biochemical criteria underwent transsphenoidal microsurgery.

The authors found an overall rate of remission of 74% at 5 years postoperatively. Patients in whom morning serum cortisol concentrations were lower than 3 µg/dl (83 nmol/L) on postoperative Day 3, following an overnight dexamethasone suppression test, had a 93% chance of remission at the 5-year follow-up examination. Patients with cortisol concentrations higher than this level uniformly failed to achieve long-term remission.

Conclusions. Transsphenoidal microsurgery is an effective means of control for patients with adrenocorticotrophic hormone—producing microadenomas. Clinical outcome correlated well with the size of the tumor, as measured on preoperative imaging studies, and with postoperative morning cortisol levels following an overnight dexamethasone suppression test. Postoperative cortisol levels can be used as a useful prognostic indicator of the likelihood of future recurrence following transsphenoidal adenomectomy in CD.
Outcomes of surgery in 1019 brachial plexus lesions treated at Louisiana State University Health Sciences Center
Authors: Kim Daniel H. , Cho Yong-Jun , Tiel Robert L. , Kline David G.
Published: May 2009

Object. Outcomes of 1019 brachial plexus lesions in patients who underwent surgery at Louisiana State University Health Sciences Center during a 30-year period are reviewed in this paper to provide management guidelines.

Methods. Causes of brachial plexus lesions included 509 stretches/contusions (50%), 161 plexus tumors (16%), 160 thoracic outlet syndromes (TOSs, 16%), 118 gunshot wounds (12%), and 71 lacerations (7%). Many features of clinical presentation, including prior treatment, patient's neurological status, results of electrophysiological studies, intraoperative findings, and postoperative level of function, were studied. The minimum follow-up period was 18 months and the mean follow-up period was 42 months. Repairs were best for injuries located at the C-5, C-6, and C-7 levels, the upper and middle trunk, the lateral cord to the musculocutaneous nerve, and the median and posterior cords to the axillary and radial nerves. Conversely, results were poor for injuries at the C-8 and T-1 levels, and for lower trunk and medial cord lesions, with the exception of injuries of the medial cord to the median nerve. Outcomes were most favorable when patients were carefully evaluated and selected for surgery, although variables such as lesion type, location, and severity, as well as time since injury also affected outcome. This was true also of TOSs and tumors arising from the plexus, especially if they had not been surgically treated previously.

Conclusions. Surgical exploration and repair of brachial plexus lesions is technically feasible and favorable outcomes can be achieved if patients are thoroughly evaluated and appropriately selected.
Changes in cerebrospinal fluid hydrodynamics following endoscopic third ventriculostomy for shunt-dependent noncommunicating hydrocephalus
Authors: Nishiyama Kenichi , Mori Hiroshi , Tanaka Ryuichi
Published: May 2009

Object. The aim of this study was to analyze physiological changes in cerebrospinal fluid (CSF) dynamics following endoscopic third ventriculostomy (ETV) for shunt-dependent noncommunicating hydrocephalus.

Methods. Clinical data obtained in 15 patients treated with ETV for shunt malfunction were analyzed. Magnetic resonance imaging studies demonstrated the obstruction of the ventricular system preoperatively. After ETV, the existing shunt system was removed and a continuous extraventricular drain, set at 30 cm H2O in height, was installed to measure daily amounts of CSF outflow. Cerebrospinal fluid dynamics after ETV were also evaluated using 111In-diethylenetriamine pentaacetic acid radioisotope cisternography in six of 15 patients within 1 month of the procedure. Three patients underwent cisternography at 6 months after ETV. Cisternograms were obtained at 1, 5, 24, and 48 hours after injection of the radioisotope. To study CSF absorptive capacity, ratios of radioisotope counts at 48 and 5 hours after injection were calculated (C48:C5). Seven of 15 patients had daily outflows of CSF of less than 20 ml; this volume decreased quickly within a few days. The other eight patients demonstrated an outflow of more than 150 ml of CSF for several days, three of whom had signs of transiently increased intracranial pressure. Their CSF outflow volume decreased gradually and symptoms improved within 1 week. Ratios of C48:C5 were within normal limits in five of six patients who had undergone cisternography 1 month after ETV. These ratios were decreased in all three patients who had undergone cisternography at 6 months after ETV compared with that measured at 1 month after the procedure.

Conclusions. Our data suggest that CSF dynamics convert from a shunt-dependent state to a shunt-independent state within 1 week following ETV in patients with shunt-dependent noncommunicating hydrocephalus. Nonetheless, intraventricular pressure does not decrease quickly in certain cases. Cerebrospinal fluid absorptive capacity or CSF circulation through the subarachnoid space may show further improvement several months after ETV.
Endoscopic third ventriculostomy for shunt dysfunction in occlusive hydrocephalus: long-term follow up and review
Authors: Boschert Jürgen , Hellwig Dieter , Krauss Joachim K.
Published: May 2009

Object. Endoscopic third ventriculostomy (ETV) is the treatment of choice for occlusive (noncommunicating) hydrocephalus. Nevertheless, its routine use in patients who have previously undergone shunt placement is still not generally accepted. The authors' aim was to investigate the long-term effects of ETV in a group of prospectively chosen patients.

Methods. Patients who underwent ETV and had previously undergone shunt placement for occlusive hydrocephalus were followed prospectively for at least 3 years (range 36–103 months, mean 63.6 months). Nine female and eight male patients ranging from 8 to 54 years of age (mean 32 years) had undergone shunt placement 0.7 to 23.5 years (mean 8.1 years) before ETV. Fifteen patients were admitted with underdrainage and two with overdrainage. In six cases, ETV was performed as an emergency operation. The origin of hydrocephalus was aqueductal stenosis in 12 cases and aqueductal compression by a tumor in two cases. Three patients suffered from a fourth ventricle outlet syndrome, and in two patients an additional malresorptive component was suspected. Thirteen patients underwent ETV with shunt removal and insertion of an external drain in one session. The drain served as a safety measure; it could be opened if raised intracranial pressure or ventricular dilation was observed on postoperative imaging studies. In the other four patients the shunt was initially ligated and then removed during a second operation.

Fourteen patients (82%) have remained shunt free. The other three patients, including the two with an additional malresorptive component, needed shunt reimplantation 3 days, 2 weeks, or 7 months after ETV.

Conclusions. Use of ETV is safe and effective for the treatment for shunt dysfunction in patients with obstructive hydrocephalus.
Treatment of staphylococcal ventriculitis associated with external cerebrospinal fluid drains: a prospective randomized trial of intravenous compared with intraventricular vancomycin therapy
Authors: Pfausler Bettina , Spiss Heinrich , Beer Ronny , Kampfl Andreas , Engelhardt Klaus , Schober Maria , Schmutzhard Erich
Published: May 2009

Object. Staphylococcal ventriculitis may be a complication in temporary external ventricular drains (EVDs). The limited penetration of vancomycin into the cerebrospinal fluid (CSF) is well known; the pharmacodynamics and efficacy of systemically compared with intraventricularly administered vancomycin is examined in this prospective study.

Methods. Ten patients in whom EVDs were implanted to treat intracranial hemorrhage and who were suffering from drain-associated ventriculitis were randomized into two treatment groups. Five of these patients (median age 47 years) were treated with 2 g/day vancomycin administered intravenously (four infusions/day, Group 1), and the other five (median age 49 years) received 10 mg vancomycin intraventricularly once daily (Group 2). Vancomycin levels were measured in serum and CSF six times a day. The maximum vancomycin level in CSF was 1.73 ± 0.4 µg/ml in Group 1 and 565.58 ± 168.71 µg/ml 1 hour after vancomycin application in Group 2 (mean ± standard deviation). Vancomycin levels above the recommended trough level of 5 µg/ml in CSF were never reached in Group 1, whereas in Group 2 they were below the trough level (3.74 ± 0.66 µg/ml) only at 21 hours after intraventricular vancomycin application. The vancomycin level in the serum was constant within therapeutic levels in Group 1, whereas in Group 2 in most instances vancomycin was almost below a measurable concentration. In both groups bacteriologically and laboratory-confirmed CSF clearance could be obtained.

Conclusions. Intraventricular vancomycin application is a safe and efficacious treatment modality in drain-associated ventriculitis, with much higher vancomycin levels being achieved in the ventricular CSF than by intravenous administration.
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: May 2009

Object. Transplantation of fetal dopaminergic tissue is being investigated in animal models and clinical trials for its potential as a treatment for advanced Parkinson disease. At the same time, the availability of fetal tissue is limited, making its storage time prior to transplantation a key practical issue. Although it results in a smaller percentage of surviving cells, a longer storage time enables fetal tissue obtained over several days to be pooled for transplantation in a recipient. Glial cell line—derived neurotrophic factor (GDNF) has been shown to improve survival of human dopaminergic tissue that has been stored prior to transplantation. The objective of this study was to evaluate the effects on fetal dopaminergic tissue of GDNF-supplemented hibernation for extended periods of 6 to 15 days.

Methods. The ventral mesencephalon (VM) was harvested in a total of 27 14-day-old rat fetuses, and three VMs were cultured immediately (fresh control group). The remaining 24 VMs were divided sagittally along the midline to yield 48 equal pieces of hemimesencephalon. Twenty-four pieces were stored with GDNF-supplemented hibernation medium for 6, 9, 12, or 15 days, and the 24 “partner” hemimesencephalon pieces 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 double-stained with cresyl violet. Cell counts for all cultures and the percentage of TH-immunoreactive cells were obtained. The percentage of TH-immunoreactive cells for the fresh control group was 6.3 ± 0.5%. The percentage of TH-immunoreactive cells in cultures derived from tissue stored in GDNF-supplemented medium was significantly increased at 6 and 9 days posthibernation compared with the fresh control group and the “partner” groups stored in hibernation medium only. No significant increase in the percentage of TH-immunoreactive cells was observed in the 12- and 15-day groups.

Conclusions. In this study the authors have demonstrated that fetal dopaminergic tissue can be safely stored for 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-immunoreactive cells prior to transplantation. These observations have practical clinical implications for collecting fetal dopaminergic cells and improving their survival after transplantation.
A population-based study of the incidence and survival rates in patients with pilocytic astrocytoma
Authors: Burkhard Christoph , Di Patre Pier-Luigi , Schüler Danielle , Schüler Georges , Yaşargil M. Gazi , Yonekawa Yasuhiro , Lütolf Urs M. , Kleihues Paul , Ohgaki Hiroko
Published: May 2009

Object. The incidence of pilocytic astrocytomas and the rate of patient survival were analyzed in a population-based study in the canton of Zürich, Switzerland.

Methods. Between 1980 and 1994, 987 astrocytic and oligodendroglial tumors were diagnosed, of which 55 (5.5%) were pilocytic astrocytomas. The incidence rate, adjusted to the World Standard Population, was 4.8 per 1 million per year. The mean age at clinical diagnosis was 19.6 ± 12.7 years, and the male/female ratio was 1.12. The most frequent tumor sites were the cerebellum (40%), followed by supratentorial locations (35%), the optic pathway and hypothalamus (11%), and the brainstem (9%). The mean follow-up period was 12 years. Observed survival rates were 100% at 5 years and 95.8% at 10 years after diagnosis (relative survival rate at 10 years: 96.8%). Seven patients (13%) received postoperative radiotherapy, but this did not significantly affect survival. In all patients the tumors were histologically classified as WHO Grade I, except in two patients who had anaplastic pilocytic astrocytoma (Grade III), one of whom died after 7 years, whereas the other was still alive after 10 years.

Conclusions. This population-based study shows that, because of the benign biological behavior of pilocytic astrocytomas and advances in microneurosurgery, the survival rates for patients with these tumors are excellent, regardless of postoperative radiotherapy.
Preservation of bone flaps in patients with postcraniotomy infections
Authors: Bruce Jeffrey N. , Bruce Samuel S.
Published: May 2009

Object. Management of postcraniotomy wound infections has traditionally consisted of operative debridement and removal of devitalized bone flaps followed by delayed cranioplasty. The authors report the highly favorable results of a prospective study in which postcraniotomy wound infections were managed with surgical debridement to preserve the bone flaps and avoid cranioplasty.

Methods. Since 1990, 13 patients with postcraniotomy wound infections have been prospectively treated with open surgical debridement and replacement of the bone flap. All patients received a full course of systemic antibiotic agents based on the determination of the bacterial culture and antibiotic sensitivity. Notable risk factors for infection included prior craniotomies, radiotherapy, and skull base procedures. The mean long-term follow-up period was 35 × 20 months. In all five patients who underwent craniotomies without complications, bone flap preservation was possible with full resolution of the infection and without the need for additional surgery. Among the eight patients with risk factors, bone preservation was possible in six patients, although two required minor wound revisions (without bone flap removal). Both patients who underwent craniofacial procedures required an additional procedure in which the bone flap was removed for recurrent infection (one after 2 months and the other after 29 months).

Conclusions. In patients with uncomplicated postcraniotomy infections, simple operative debridement is sufficient and it is not necessary to discard the bone flaps and perform cranioplasties. Even patients with risk factors such as prior surgery or radiotherapy can usually be treated using this strategy. Patients who undergo craniofacial surgeries involving the nasal sinuses are at higher risk and may require bone flap removal.
Regional cerebral blood flow monitoring in the diagnosis of delayed ischemia following aneurysmal subarachnoid hemorrhage
Authors: Vajkoczy Peter , Horn Peter , Thome Claudius , Munch Elke , Schmiedek Peter
Published: May 2009

Object. The goal of this study was to evaluate regional cerebral blood flow (rCBF) monitoring, performed using thermal-diffusion (TD) flowmetry, as a novel means for the bedside diagnosis of symptomatic vasospasm.

Methods. Fourteen patients with high-grade subarachnoid hemorrhage (SAH) who underwent early clip placement for anterior circulation aneurysms were prospectively entered into the study. Thermal-diffusion microprobes were implanted into the white matter of vascular territories that were deemed at risk for developing symptomatic vasospasm. Data on arterial blood pressure, intracranial pressure, cerebral perfusion pressure, rCBF measurement obtained using a TD probe (TD-rCBF), cerebrovascular resistance (CVR), and blood flow velocities were collected at the patient's bedside. The diagnosis of symptomatic vasospasm was based on the manifestation of a delayed ischemic neurological deficit and/or a reduced territorial level of CBF as assessed using stable Xe-enhanced computerized tomography (CT) scanning in combination with vasospasm demonstrated by angiography.

Bedside monitoring of TD-rCBF and CVR allowed the detection of symptomatic vasospasm. In the 10 patients with vasospasm the TD-rCBF decreased from 21 ± 4 to 9 ± 1 ml/100 g/min (mean ± standard error of the mean), whereas in the four other patients the TD-rCBF value remained unchanged (mean TD-rCBF = 25 ± 4 compared with 21 ± 4 ml/100 g/min). A comparison of the results of TD-rCBF and Xe-enhanced CT studies, as well as the calculation of sensitivities, specificities, predictive values, and likelihood ratios, identified a TD-rCBF value of 15 ml/100 g/min as a reliable cutoff for the diagnosis of symptomatic vasospasm. In addition, TD flowmetry was characterized by a more favorable diagnostic reliability than transcranial Doppler ultrasonography.

Conclusions. Thermal-diffusion flowmetry represents a promising method for the bedside monitoring of patients with SAH to detect symptomatic vasospasm. This is of major clinical interest for patients with high-grade SAH, who often cannot be assessed neurologically.
Selective peripheral denervation for the treatment of intractable spasmodic torticollis: experience with 168 patients at the Mayo Clinic
Authors: Cohen-Gadol Aaron A. , Ahlskog J. Eric , Matsumoto Joseph Y. , Swenson Mary A. , McClelland Robyn L. , Davis Dudley H.
Published: May 2009

Object. Selective peripheral denervation is currently the primary surgical treatment for intractable cervical dystonia. The authors assessed preoperative factors to determine which, if any, correlated with outcomes in patients with torticollis who had undergone this procedure.

Methods. The records of 168 consecutive patients who had undergone selective peripheral denervation for cervical dystonia between 1988 and 1996 at the Mayo Clinic were reviewed. There were 89 women (53%) and 79 men (47%) with a mean age of 53.4 years. Selection of muscles for denervation was based on the patient's clinical presentation and electromyography mapping results. The most common torticollis vectors were rotational in 141 patients (84%) and laterocollis in 59 (35%). Seventy patients (42%) presented with combined vectors. The technique used to remedy both conditions involved denervation of the ipsilateral posterior cervical paraspinal and splenius capitis muscles. Denervation of the sternocleidomastoid muscle was performed on the contralateral side for rotational torticollis and on the ipsilateral side for laterocollis. A rigorous physical therapy program followed surgery.

At the 3-month postoperative evaluation, 125 patients (77%) of the 162 who were available for follow up had moderate to excellent improvement in their head position, and pain was moderately to markedly improved in 131 patients (81%). The long-term follow up lasted a mean of 3.4 years and was undertaken in 130 patients. The original level of moderate to excellent improvement in head position and pain was retained in at least 71 patients (70%). Outcome was not predicted by preoperative head position, severity of abnormal posture of head, symptom duration, presence of tremor or phasic dystonic movements, or failure to respond to botulinum toxin treatment. Five patients recovered from postoperative complications including one myocardial infarction, one pulmonary embolism, and three respiratory failures. Three patients suffered from persistent C-2 distribution dysesthesias and three from slight shoulder weakness; one had a wound infection, and one died of respiratory arrest.

Conclusions. Selective peripheral denervation is an effective method of achieving lasting improvement of dystonia in most patients with intractable torticollis.