bluuebunny/crossref_metadata_2025 huggingface dataset:
Thalamic stimulation and functional magnetic resonance imaging: localization of cortical and subcortical activation with implanted electrodes
Authors: Rezai Ali R. , Lozano Andres M. , Crawley Adrian P. , Joy Michael L. G. , Davis Karen D. , Kwan Chun L. , Dostrovsky Jonathan O. , Tasker Ronald R. , Mikulis David J.
Published: January 2008

The utility of functional magnetic resonance (fMR) imaging in patients with implanted thalamic electrodes has not yet been determined. The aim of this study was to establish the safety of performing fMR imaging in patients with thalamic deep brain stimulators and to determine the value of fMR imaging in detecting cortical and subcortical activity during stimulation.

Functional MR imaging was performed in three patients suffering from chronic pain and two patients with essential tremor. Two of the three patients with pain had undergone electrode implantation in the thalamic sensory ventralis caudalis (Vc) nucleus and the other had undergone electrode implantation in both the Vc and the periventricular gray (PVG) matter. Patients with tremor underwent electrode implantation in the ventralis intermedius (Vim) nucleus. Functional MR imaging was performed during stimulation by using a pulse generator connected to a transcutaneous extension lead. Clinically, Vc stimulation evoked paresthesias in the contralateral body, PVG stimulation evoked a sensation of diffuse internal body warmth, and Vim stimulation caused tremor arrest.

Functional images were acquired using a 1.5-tesla MR imaging system. The Vc stimulation at intensities provoking paresthesias resulted in activation of the primary somatosensory cortex (SI). Stimulation at subthreshold intensities failed to activate the SI. Additional stimulation-coupled activation was observed in the thalamus, the secondary somatosensory cortex (SII), and the insula. In contrast, stimulation of the PVG electrode did not evoke paresthesias or activate the SI, but resulted in medial thalamic and cingulate cortex activation. Stimulation in the Vim resulted in thalamic, basal ganglia, and SI activation.

An evaluation of the safety of the procedure indicated that significant current could be induced within the electrode if a faulty connecting cable (defective insulation) came in contact with the patient. Simple precautions, such as inspection of wires for fraying and prevention of their contact with the patient, enabled the procedure to be conducted safely. Clinical safety was further corroborated by performing 86 MR studies in patients in whom electrodes had been implanted with no adverse clinical effects.

This is the first report of the use of fMR imaging during stimulation with implanted thalamic electrodes. The authors' findings demonstrate that fMR imaging can safely detect the activation of cortical and subcortical neuronal pathways during stimulation and that stimulation does not interfere with imaging. This approach offers great potential for understanding the mechanisms of action of deep brain stimulation and those underlying pain and tremor generation.
Workforce demand for neurosurgeons in the United States of America: a 13-year retrospective study
Authors: Friedlich Daniel L. , Feustel Paul J. , Popp A. John
Published: January 2008

Object

The workforce demand for neurosurgeons was quantified by a review and an analysis of journal recruitment advertisements published over the past 13 years.

Methods

A retrospective analysis of recruitment advertisements from July 1985 through June 1998 was performed by examining issues of the Journal of Neurosurgery and Neurosurgery. Advertisement information that appeared in each journal during the last 3 years was collected from alternating months (July to May); information that appeared prior to that time was collected from alternating recruitment years back to 1985. The authors examined the following workforce parameters: practice venue, subspecialization, and practice size.

They found no significant decrease in neurosurgical recruitment advertisements. There was an average of 102.7 ± 22.4 (standard deviation) advertised positions per year during the most recent 3 years compared with 92.6 ± 17.9 advertised positions per year during the preceding decade. Similarly, there has been no decline in advertised positions either in academic (33 ± 6.1/year for the most recent 3 years compared with 32.8 ± 5.9/year for 1985–1995) or private practice (69.7 ± 21.6/year for the most recent 3 years compared with 59.8 ± 13.4/year for 1985–1995). A shift in demand toward subspecialty neurosurgery was observed. During the past 3 years, 31.2 ± 5.9% of advertised positions called for subspecialty expertise, compared with 18.5 ± 2.8% for the preceding decade (p < 0.05). The largest number of subspecialty advertisements designated positions for spine and pediatric neurosurgeons. Private practice advertisements increasingly sought to add neurosurgeons to group practices.

Conclusions

Contrary to previous reports and a prevailing myth, our data show no decrease in workforce demand for neurosurgeons in the United States over the past 3 years compared with the prior decade. A shift toward subspecialist recruitment, particularly for spine neurosurgeons, has been demonstrated in both academic and private practice venues.
Concurrent three dimensional neuroendoscopy: initial descriptions of application to clinical practice
Authors: Chen Joseph C. T. , Levy Michael L. , Corber Ziv , Assifi Murwarid Mura
Published: January 2008

Applications of endoscopic technique neurosurgery are becoming increasingly popular as greater evidence of the safety and efficacy of these techniques is reported. Nevertheless, significant technical limitations need to be solved before neuroendoscopy can achieve widespread popularity. One limitation is the surgeon's difficulties in becoming anatomically oriented in a two-dimensional (2-D) environment. The lack of appropriate visual cues to orient oneself in three-dimensional (3-D) space makes relatively simple anatomical regions difficult to navigate. The authors describe an endoscopy system that allows for stereoscopic visualization during minimally invasive procedures and that acts as an adjunct to conventional open craniotomies. Four cases are described in which stereoendoscopy was used as either a primary means of visualization or as an adjunct to the operating microscope in conventional open neurosurgical procedures. The authors believe that stereoendoscopic vision is a significant advance in endoscope technology and will play a large role in the popularization of minimally invasive techniques in neurosurgery.
Improved safety of neuroendoscopic third ventriculostomy by using an operative Doppler ultrasound probe
Authors: Vloeberghs Michael , Cartmill Maria
Published: January 2008

In this paper the authors describe the use of a Doppler device, originally built for intravascular use, that is passed through a flexible neuroendoscope during a neuroendoscopic third ventriculostomy (NTV) procedure to treat for hydrocephalus. There was no morbidity associated with the use of this Doppler probe, and the procedure was not significantly lengthened. The Doppler probe was very accurate in locating the position of the basilar artery tip and assured the safety of NTV.
Neuroendoscopic approach to tectal tumors: a consecutive series
Authors: Oka Kazunari , Kin Yoshiaki , Go Yoshinori , Hirakawa Katsuyuki , Tomonaga Masamichi , Inoue Tohru , Yoshioka Susumu
Published: January 2008

The authors report a consecutive series of 10 patients who presented with signs and symptoms caused by tectal tumors. Clinical findings, radiographic features, neuroendoscopic management strategies, and histological findings are reported and discussed.

Since January 1990, 11 neuroendoscopic procedures were performed in 10 patients who harbored tectal tumors. The patients were followed for an average of 5 years (range 2 months to 12 years), and a retrospective study was conducted in which case notes, radiological findings, operative notes, and histopathological findings were assessed. Magnetic resonance (MR) imaging was performed, and the images were used to classify patients into three groups: those with hypertrophy of the tectum in whom isointensity appeared on T1-weighted images (Group 1); those with a tectal tumor occupying the cerebral aqueduct in whom decreased signal intensity appeared on T1-weighted images, as well as no enhancement after gadolinium administration (Group 2); and those with a tectal tumor in whom mixed signal intensity appeared on T1-weighted images and conspicuous evidence of contrast enhancement (Group 3). The results of histological examination were consistent with MR imaging features: in Group 1, glial tissue or gliosis; in Group 2, benign astrocytoma; and in Group 3, malignant astrocytoma. Cerebrospinal fluid diversion was the only surgical treatment that provided relief from obstructive hydrocephalus. One patient in Group 3 underwent radiotherapy and subsequent partial tumor removal under neuroendoscopic guidance. Thereafter, the tumor remained in decline. All patients had normal intellectual status after undergoing surgery in which a neuroendoscope was used.

Neuroendoscopic procedures can provide histological diagnosis, define the tumor-midbrain interrelationship, and be highly effective in treating obstructive hydrocephalus and in removing tectal tumors. This procedure may receive clinical application as a new management strategy for tectal glioma.
Endoscopy of the posterior fossa and endoscopic dissection of acoustic neuroma
Authors: Göksu Nebil , Bayazit Yildirim , Kemaloglu Yusuf
Published: January 2008

The objective of this study was to evaluate the importance of endoscopes in eliminating the disadvantage of posterior fossa approach--that is, the lack of adequate visualization obtained of the lateral aspect of the internal acoustic canal (IAC).

Over a 10-year period 32 patients underwent removal of acoustic neuroma (AN) via a combined retrosigmoid retrolabyrinthine approach (CRSRL). Endoscopes were used at different stages of the operation, and their use was evaluated with regard to elimination of the disadvantages of the posterior fossa approach.

All patients in whom AN had been diagnosed underwent surgery. A standard combined retrosigmoid retrolabyrinthine approach was performed. Standard sinus endoscopes of 0, 30, and 70° were introduced into the cerebellopontine angle before debulking the tumor, and the IAC was inspected at the end of the operation. Neurovascular integrity as well as the relationship between AN and surrounding structures were evaluated. The IAC was inspected for residual tumor, and if any was found, endoscopic tumor dissection was performed.

Endoscopes have facilitated the understanding of the relationship between AN and neighboring neurovascular structures. The disadvantage of posterior fossa approach can be eliminated by using endoscopes.

In surgery in which the posterior fossa approach is performed, endoscopes can be used to make operations safer. In addition to allowing inspection of the fundus, it is possible to perform tumor dissection within the IAC by using the endoscopes.
Fatal subarachnoid hemorrhage after endoscopic third ventriculostomy
Authors: Schroeder Henry W. S. , Warzok Rolf W. , Assaf Jamal A. , Gaab Michael R.
Published: January 2008

In recent years, endoscopic third ventriculostomy has become a well-established procedure for the treatment of various forms of noncommunicating hydrocephalus. Endoscopic third ventriculostomy is considered to be an easy and safe procedure. Complications have rarely been reported in the literature. The authors present a case in which the patient suffered a fatal subarachnoid hemorrhage (SAH) after endoscopic third ventriculostomy.

This 63-year-old man presented with confusion and drowsiness and was admitted in to the hospital in poor general condition. Computerized tomography scanning revealed an obstructive hydrocephalus caused by a tumor located in the cerebellopontine angle. An endoscopic third ventriculostomy was performed with the aid of a Fogarty balloon catheter. Some hours postoperatively, the patient became comatose. Computerized tomography scanning revealed a severe perimesencephalic-peripontine SAH and progressive hydrocephalus. Despite emergency external ventricular drainage, the patient died a few hours later.

Although endoscopic third ventriculostomy is considered to be a simple and safe procedure, one should be aware that severe and sometimes fatal complications may occur. To avoid vascular injury, perforation of the floor of the third ventricle should be performed in the midline, halfway between the infundibular recess and the mamillary bodies, just behind the dorsum sellae.
Anterior thoracic intradural arachnoid cysts
Authors: Caruso Gerardo , Germanò Antonino , Caffo Mariella , Belvedere Massimo , La Rosa Giovanni , De Divitiis Oreste , Tomasello Francesco
Published: January 2008

Anterior thoracic intradural arachnoid cysts (ATIACs) are a rare cause of spinal cord and nerve root compression, for which different treatment strategies have been proposed. Although ATIAC represents a well-known clinical entity, the choice of surgical method has not been uniform, and no study has been specifically designed to compare the results of the different treatment options adopted.

The authors report the case of a 40-year old man with a 1-year history of dorsal pain, weakness in the lower extremities, gait disturbance, and mild sexual and urinary dysfunction. On neurological examination spastic paraparesis, lower-extremity hypertonia, and hypesthesia below T-2 were demonstrated. Magnetic resonance imaging revealed the presence of an ATIAC at the T-2 level. The patient underwent complete microsurgical removal of the cyst.

The authors conducted a Medline search of the relevant literature from 1966 to 1998 and also obtained data on other cases in which patients underwent surgical treatment of ATIAC. The literature search yielded five such cases. Treatment strategies were complete excision and fenestration followed by placement of a shunt. In addition, one case was characterized by intraoperative cyst rupture during retraction of the spinal cord.

Correct preoperative workup coupled with microneurosurgical technique allow for successful removal of the lesion and excellent outcome. Based on the literature review and the results in our case, the complete excision of ATIAC is associated with an excellent outcome, which is different from results achieved using other surgical strategies.
Extensive arachnoid ossification with associated syringomyelia presenting as thoracic myelopathy
Authors: Slavin Konstantin V. , Nixon Randall R. , Nesbit Gary M. , Burchiel Kim J.
Published: January 2008

The authors present the case of a patient in whom progressive thoracic myelopathy was caused by the extensive ossification of the arachnoid membrane and associated intramedullary syrinx. Based on their findings and the results of a literature search, they describe a pathological basis of this rare condition, discuss its incidence and symptomatology, and suggest a simple classification of various types of the arachnoid ossification. They also discuss magnetic resonance imaging features of arachnoid ossification and associated spinal cord changes. Emphasis is placed on the particular value of plain computerized tomography, which is highly sensitive for detecting intraspinal calcifications and ossifications, in the diagnostic evaluation of patients whose clinical picture indicates progressive myelopathy.
Painful supernumerary phantom arm following motor cortex stimulation for central poststroke pain
Authors: Canavero Sergio , Bonicalzi Vincenzo , Castellano Giancarlo , Perozzo Paula , Massa-Micon Barbara
Published: January 2008

In this report, the authors describe a case in which the patient began to experience a supernumerary phantom arm after she received motor cortex stimulation for central pain. The patient had a history of right thalamocapsular stroke. It is speculated that the motor cortex activation triggered a response in the patient's parietal lobe, precipitating perception of the phantom limb.

To the authors' knowledge this is the first reported case of its kind.
Endoscopic transpedicular thoracic discectomy
Authors: Jho Hae-Dong
Published: January 2008

Object

To minimize the invasiveness and maximize the adequacy of the decompressive proceedure in thoracic discectomy, a 70° endoscope was adopted to perform transpedicular thoracic discectomy.

Methods

A posterior transpedicular approach was performed via a 2-cm transverse skin incision, using the operating microscope or a 0°-lens endoscope. Using a 70°-lens endoscope, discectomy was performed after obtaining direct visualization of the ventral aspect of the spinal cord dura mater. This surgical technique has been used in 25 patients. There were 12 men and 13 women whose age ranged from 29 to 70 years (median 46 years). Thirteen patients experienced myelopathy, with or without radiculopathy, 10 presented with radiculopathy, and two patients suffered from segmental pain. The follow-up period ranged from 4 to 60 months (median 27 months). In 12 of the 13 patients with myelopathy, excellent improvement was shown postoperatively. In the remaining patient, symptoms recurred when she was injured in a motor vehicle accident 3 months postsurgery. In nine of 10 patients with radiculopathy pain resolved completely. In the one patient with right-sided hypochondral pain and in the two patients with segmental pain no relief was obtained despite excellent discectomy results that were demonstrated on postoperative magnetic resonance images. The average length of hospital stay was overnight.

Conclusions

The use of a 70°-lens endoscope via a transpedicular route has made thoracic discectomy comparable with cervical or lumbar discectomy in its surgical invasiveness, in the patient's recovery time, and in complexity of surgical procedure.
Endoscopic thoracic sympathectomy
Authors: Johnson J. Patrick , Obasi Chinyere , Hahn Michael S. , Glatleider Paul
Published: January 2008

Thoracic sympathectomy has evolved as a treatment option for patients with hyperhidrosis and pain disorders. In the past surgical procedures were highly invasive and caused significant morbidity, but the minimally invasive thoracoscopic procedure provides detailed visualization of the sympathetic ganglia and is associated with minimal postoperative morbidity. In a previously published series the authors performed 60 thorascopic procedures in 39 patients; in this paper, they report the addition of 52 procedures performed in 26 patients, for a total of 112 procedures in 65 patients. Overall, the outcomes were equivalent to those for previously established open surgical techniques; however, the rate of surgery-related morbidity, length of hospital stay, and time until return to normal activity were substantially reduced. Complications and recurrence of symptoms were comparable with those demonstrated in previous reports. Overall patient satisfaction and willingness to undergo a repeat operative procedure ranged from 66 to 99%. Postoperatively, higher satisfaction rates were observed in patients with hyperhidrosis whereas in those with pain syndromes, satisfaction rates were lower. Minimally invasive thoracoscopic sympathectomy procedures are useful in treating sympathetically mediated disorders, and the results indicated that the procedure is associated with reduced morbidity and similar outcome when compared with results obtained after open surgery. Hyperhidrosis is well treated, but patients with pain syndromes have significantly poorer outcomes.
Thoracoscopic microsurgical excision of herniated thoracic discs
Authors: Rosenthal Daniel , Dickman Curtis A.
Published: January 2008

Object

The authors began using thoracoscopy to treat pathological conditions of the spine in 1992. In this study they delineate their clinical experience in which this procedure was used to resect herniated thoracic discs.

Methods

Fifty-five patients underwent thoracoscopy for the resection of herniated thoracic discs. Thirty-six patients presented with myelopathies and 19 with incapacitating thoracic radicular pain. Forty-three patients underwent a single-level, 11 a two-level, and one a three-level discectomy. The mean operative time for thoracoscopic microdiscectomy was 3 hours and 25 minutes (range 80-542 minutes) and the mean blood loss was 327 ml (range 124-1500 ml). Compared with thoracotomy, which was performed in 18 patients, thoracoscopy was associated with a mean of 1 hour less operative time and less than one-half of the blood loss, duration of chest tube drainage, usage of pain medication, and length of hospitalization. Compared with costotransversectomy, which was performed in 15 patients, thoracoscopy permitted more complete resection of calcified and midline thoracic discs because it provided a direct view of the entire anterior surface of the dura. Thoracotomy was associated with a significantly greater incidence of prolonged, disabling intercostal neuralgia compared with the mild transient episodes of intercostal neuralgia associated with thoracoscopy (50% compared with 16%). Thoracotomy also was associated with a significantly higher incidence of postoperative atelectasis and pulmonary dysfunction than thoracoscopy (33% compared with 7%). Clinical and neurological outcomes were excellent (mean follow-up period 15 months). Among the 36 myelopathic patients, 22 completely recovered neurologically; five improved functionally but had some residual myelopathic symptoms; and nine stabilized. Among the 19 patients with isolated thoracic radiculopathies, 15 recovered completely; four improved moderately; and none had worsened radicular pain.

Conclusions

Thoracoscopic microdiscectomy is a reliable surgical technique that can be performed safely with excellent clinical and neurological results.
Predicting the probability of meningioma recurrence based on the quantity of peritumoral brain edema on computerized tomography scanning
Authors: Mantle Ross E. , Lach Boleslaw , Delgado Mauricio R. , Baeesa Salleh , Bélanger Gerard
Published: January 2008

Object

The goal of this study was to determine whether the quantity of peritumoral brain edema displayed on computerized tomography (CT) scanning could be correlated with brain invasion and subsequent recurrence of meningiomas.

Methods

One hundred thirty-five patients who underwent resection of intracranial meningiomas at the Ottawa Civic Hospital were followed during the period 1980 to 1998. A complete resection was defined as one in which tumor, invaded bone, and involved dura were removed. Tumors were examined microscopically for evidence of brain invasion. The mean follow-up period was 9 years (± 4 years, standard deviation [SD]) and the mean time to recurrence was 5 years (± 4 years, SD). The authors used a simple grading system based on the average thickness (in centimeters) of edema seen on an axial CT slice showing the most tumor. Edema grade was linearly related to edema volume determined by digitizing the scans (r = 0.96; 29 cases). The chance of brain invasion increased by 20% for each centimeter of edema (rs = 1, p < 0.0001; 124 cases). The presence of brain invasion was predictive of recurrence after complete resection with an accuracy of 83%, a sensitivity of 89%, and a specificity of 82%. The chance of recurrence within 10 years after complete resection was given by the equation: percentage chance of recurrence = (centimeter of edema)3 X 0.7, which can be used to predict the chance of recurrence based on findings on CT scans (rs = 1.00, p < 0.0001; 86 patients). Statistical significance was confirmed using Kaplan-Meier and univariate and multivariate analyses. Completeness of resection was the most powerful predictor of recurrence (p < 0.00001, r = 0.6), followed by edema grade and brain invasion (both p = 0.02, r = 0.1). Patient age and gender and tumor location, size, and histological subtype were nonsignificant factors.

Conclusions

Brain invasion causes peritumoral edema. Invaded brain tissue is also the source of residual cells in cases of tumor recurrence after gross-total resection.
Review of 31 cases of anterior thoracolumbar fixation with the anterior thoracolumbar locking plate system
Authors: Wilson John A. , Bowen Sam , Branch Charles L. , Meredith J. Wayne
Published: January 2008

Anterior fixation devices for the thoracolumbar spine have gained wide acceptance as viable alternatives to long-segment posterior fixation in cases of thoracolumbar spine trauma. This review was undertaken to evaluate the safety and efficacy of the Synthes anterior thoracolumbar locking plate (ATLP) system.

Over a 3-year period, 31 patients with unstable traumatic fractures of the thoracolumbar spine underwent corpectomy, placement of a structural bone graft, and anterior fixation in which the Synthes ATLP system was used. Long-term follow-up data were obtained in 29 patients. Two patients were lost to follow up, one at 4 months and the other at 1 year. In the remaining patients, the average length of follow up was 20 months. In all patients radiographic evidence of solid bone fusion was demonstrated on follow-up plain x-ray films, and there were no signs or symptoms of pseudarthrosis. No patient suffered neurological deterioration as a result of surgery, and there was relatively little morbidity associated with this plating system. To date, none of the patients in this study has developed any delayed complications related to the fixation device. In one patient, who had sustained a severe flexion injury, loosening of the anterior fixation device occurred, and the patient developed progressive kyphosis, which required a posterior stabilization procedure.

These results appear slightly better than those obtained in published studies in which other anterior plating systems were used, indicating that this system is safe and effective in the treatment of unstable fractures of the thoracolumbar spine.
Percutaneous vertebroplasty in vertebral osteonecrosis (Kümmell's spondylitis)
Authors: Do Huy M. , Jensen Mary E. , Marx William F. , Kallmes David F.
Published: January 2008

The authors report the clinical symptoms and response to therapy of a series of patients who presented with subacute or chronic back pain due to vertebral osteonecrosis (Kümmell's spondylitis) and who underwent percutaneous vertebroplasty.

The authors performed a retrospective chart review of a series of 95 patients in whom 149 painful, nonneoplastic compression fractures were demonstrated and who were treated with percutaneous transpediculate polymethylmethacrylate (PMMA) vertebroplasty. In six of these patients there was evidence of vertebral osteonecrosis, as evidenced by the presence of an intravertebral vacuum cleft on radiography or by intravertebral fluid on magnetic resonance (MR) imaging. Clinical and radiological findings on presentation were noted. Technical aspects of the vertebroplasty technique were compiled. Response to therapy, defined as qualitative change in pain severity and change in level of activity, was noted immediately following the procedure and at various periods on follow-up reviews.

One man and five women, who ranged in age from 72 to 90 years (mean 81 years), were treated. Each patient had one compression fracture. The fractures were at T-11 (one patient), L-1 (two patients), L-3 (two patients), and L-4 (one patient). The pain pattern was described as severe and localized to the affected vertebra, and sometimes radiated along either flank. Pain duration ranged from 2 to 12 weeks, and the pain was refractory to conservative therapy that consisted of bedrest, analgesics, and external bracing. At the time of treatment, all patients were bedridden because of severe back pain. In all patients either plain radiographic or computerized tomography evidence of intravertebral vacuum cleft or MR imaging evidence of vertebral fluid collection consistent with avascular necrosis of the vertebral body was demonstrated. Four patients underwent bilateral transpediculate vertebroplasty, and two patients underwent unilateral transpediculate vertebroplasty. The fracture cavities were specifically targeted for PMMA injection. Additional fortification of the osteoporotic vertebral body trabeculae was also performed when feasible. "Cavitygrams" or intraosseous venograms with gentle contrast injection were obtained prior to application of cement mixture. In all patients subjective improvement in pain and increased mobility were demonstrated posttreatment. The follow-up period ranged from 4 to 24 hours after treatment. Two patients made additional office visits at 1 and 3 months, respectively.

Patients presenting with vertebral osteonecrosis (Kümmell's spondylitis) often suffer from local paraspinous or referred pain. When performing vertebroplasty on these patients, confirmation of entry into the fracture cavities with contrast-enhanced "cavitygrams" should be performed prior to injection of PMMA cement. The response to vertebroplasty with regard to amelioration of pain and improved mobility is encouraging.
A new technique for the surgical management of unstable thoracolumbar burst fractures: a modification of the anterior approach and an outcome comparison to traditional methods
Authors: Wiggins Gregory C. , Rauzzino Michael J. , Shaffrey Christopher I. , Nockels Russ P. , Whitehill Richard , Shaffrey Mark E. , Wagner James , Alden Tord D.
Published: January 2008

This study was conducted to determine the safety, efficacy, and complication rate associated with the anterior approach in the use of a new titanium mesh interbody fusion cage for the treatment of unstable thoracolumbar burst fractures. The experience with this technique is compared with the senior authors' (C.S., R.W., and M.S.) previously published results in the management of patients with unstable thoracolumbar burst fractures.

Between 1996 and 1999, 21 patients with unstable thoracolumbar (T12-L3) burst fractures underwent an anterolateral decompressive procedure in which a titanium cage and Kaneda device were used. Eleven of the 21 patients had sustained a neurological deficit, and all patients improved at least one Frankel grade (average 1.2 grades). There was improvement in outcome in terms of blood loss, correction of kyphosis, and pain, as measured on the Denis Pain and Work Scale, in our current group of patients treated via an anterior approach when compared with the results in those who underwent a posterior approach.

In our current study the anterior approach was demonstrated to be a safe and effective technique for the management of unstable thoracolumbar burst fractures. It offers superior results compared with the posterior approach. The addition of the new titanium mesh interbody cage to our previous anterior technique allows the patient's own bone to be harvested from the corpectomy site and used as a substrate for fusion, thereby obviating the need for iliac crest harvest. The use of the cage in association with the Kaneda device allows for improved correction of kyphosis and restoration of normal sagittal alignment in addition to improved functional outcomes.
Microsurgical anatomy of the extracranial-extradural origin of the posterior inferior cerebellar artery
Authors: Fine Andrew D. , Cardoso Alberto , Rhoton Albert L.
Published: January 2008

Object

The authors describe the microsurgical anatomy of the posterior inferior cerebellar artery (PICA) with an extradural origin and discuss its importance as a common variation.

Methods

The microsurgical anatomy of paired PICAs with an extradural origin were examined.

Conclusions

Five to 20% of PICAs have an extradural origin. In the case described, both PICAs arose extradurally from the third segment of the vertebral artery (VA). Both origins were less than 1 cm proximal to the site at which the VA penetrated the dura and neither PICA gave rise to extradural branches. Extradurally the PICAs coursed parallel to the VA and the C-1 nerve and the three structures penetrated the dura together. Intradurally, the PICAs remained lateral and posterior to the brainstem, whereas, in the common PICA configuration, the first segment of the PICA courses anterior to the medulla. Neither PICA sent branches to the anterior brainstem, which is commonly found in PICAs with an intradural origin. There were no soft-tissue or bone anomalies.
Molecular biology of the primitive neuroectodermal tumor: a review
Authors: Raffel Corey
Published: January 2008

In terms of its molecular biology and molecular genetics, medulloblastoma is the most thoroughly studied of the pediatric brain tumors. Alterations in chromosome 17, usually an isochromosome 17q, are the most common cytogenetic abnormalities. Similarly, deletion of the short arm of one 17 chromosome, the result of formation of an iso17q, is the most common molecular biological abnormality found. The gene or genes important in the development of medulloblastoma found on chromsome 17 have not yet been identified. Both a tumor suppressor gene and an oncogene have been identified that may play a role in the development of this tumor type. The Patched (PTC) tumor suppressor gene is inactivated in approximately 15% of medulloblatomas; this alteration may be specific to the desmoplastic variant. Oncogenic mutations in the beta-catenin gene are found in a small subset of medulloblastomas. Both of these genes play central roles in developmental pathways. Prognosis in this tumor type has been related to the level of expression of the neurotrophin receptor trkC. In this review, these and other molecular biological and genetic findings are discussed with respect to the development of medulloblastoma.
Seven-year clinical experience with the Codman Hakim programmable valve: a retrospective study of 583 patients
Authors: Zemack Göran , Romner Bertil
Published: January 2008

A retrospective study was undertaken to assess the value of the Codman Hakim programmable valve in the treatment of 583 patients (421 adults and 162 children) with hydrocephalus of various causes (379), normal-pressure hydrocephalus (NPH) (174), an arachnoidal cyst (14), and pseudotumor cerebri (16). In all patients the programmable valve was implanted (the valve can be noninvasively adjusted to settings in the range of 30-200 mm H2O). In 73% of the cases this was their first shunt implantation. Ninety-two percent of the shunts drained to the peritoneal cavity and 8% to the atrium. In 42% of the cases valve pressure adjustment was required at least once (mean number of adjustments 1.2, maximum 23).

The authors present reprogramming statistics, and strategies for reprogramming are discussed. In 65% of the cases in which pressure adjustments were required, reprogrammings improved the patients' clinical status. The overall infection rate was 8.5% (56 of 660 valve implantations). Valve malfunction, blockage, or reprogramming difficulty occurred in 17 cases, and nontraumatic subdural fluid collections were demonstrated in 30 cases (13 of which were treated by valve pressure reprogramming alone). Of the patients undergoing first-time shunt placement, 21.5% eventually underwent shunt revision at least once, and a total of 318 revisions were performed during the 7-year follow-up period. At follow up, 97% of children and 90% of adults had improved.

In conclusion, catheter-related complications and shunt-related infections were the main reasons for revision and the major cause of shunt failure. Few incidents of valve malfunction were observed. The Hakim Codman programmable valve is of value in the treatment of hydrocephalus of all causes, especially in the treatment of patients with NPH, pseudotumor cerebri, arachnoidal cyst, aqueductal stenosis, traumatic hydrocephalus, and intraventricular hemorrhage.
Decreased c-fos expression in experimental neonatal hydrocephalus: evidence for reduced neuronal activation
Authors: McAllister James P. , Wood Arcangela S. , Johnson Martha J. , Connelly Robert W. , Skarupa David J. , Secic Michelle , Luciano Mark G. , Harris Neil G. , Jones Hazel C.
Published: January 2008

Although neonatal hydrocephalus often results in residual neurological impairments, little is known about the cellular mechanisms responsible for these deficits. The immediate early gene, fos (c-fos), functions as a “third messenger” to regulate protein synthesis and is a good marker for neuronal activation. To identify functional changes in neurons at the cellular level, the authors quantified fos RNA expression and localized fos protein in the H-Tx rat model of congenital hydrocephalus. Tissue samples from sensorimotor and auditory regions were obtained from hydrocephalic rats and age-matched, normal litter mates at 1, 6, 12, and 21 days of age (four-six animals in each group) and processed for immunohistochemical analysis of fos and Northern blot analysis of RNA. At 12 days of age, hydrocephalic animals exhibited significant decreases in the ratio of fos immunoreactive cells to Nissl-stained neurons from both cortical regions, but no statistical differences were noted in fos expression. At 21 days of age, both the ratio of fos immunoreactive cells to Nissl-stained neurons and fos expression decreased significantly. The number of fos-positive neurons decreased in all cortical layers but was most prominent in layers V through VI. This decrease did not appear to be caused by neuronal death because examination of Nissl-stained sections revealed many viable neurons within the areas where fos immunoreactivity was absent. These results suggest that progressive neonatal hydrocephalus reduces the capacity for neuronal activation in the cerebral cortex, primarily in those neurons that provide corticofugal projections, and that this impairment may begin during relatively early stages of ventriculomegaly.
Risk factors for repeated cerebrospinal shunt failures in pediatric patients with hydrocephalus
Authors: Tuli Sagun , Drake James , Lawless Jerry , Wigg Melanie , Lamberti-Pasculli Maria
Published: January 2008

Repeated cerebrospinal fluid (CSF) shunt failures in pediatric patients who have undergone neurosurgical procedures are common, and they are a significant cause of morbidity and occasionally mortality. To date, the risk factors for repeated failure have not been established. By performing survival analysis for repeated events, the authors examined the effects of patient characteristics, shunt hardware, and surgical details in a large cohort of patients.

During a 10-year period all pediatric patients with hydrocephalus requiring CSF diversionary procedures were included in a prospective single-institution observational study. Patient characteristics were defined as age, gender, weight, head circumference; American Society of Anesthesiology class, and the cause of hydrocephalus. Surgical details included whether the procedure was performed on an emergency or nonemergency basis, use of antibiotics, concurrent other surgical procedures, and the duration of surgical procedure. Details on shunt hardware included the type of shunt, the valve system, whether the shunt system included multiple or complex components, the type of distal catheter, site of the shunt, and side on which the shunt was placed.

Repeated shunt failures were assessed with multivariable time-to-event analysis (using the Cox regression model). Conditional models (as established by Prentice, et al.) were formulated for gap times (that is, times between successive shunt failures).

There were 1183 shunt failures in 839 patients. Failure time from the first shunt procedure was an important predictor for the second and third episodes of failures, thus establishing an association between the times to failure within individual patients. Age of less than 40 weeks gestation at time of the first shunt implantion carried a hazard ratio (HR) of 2.49 (95% confidence interval [CI] 1.68-3.68) for the first failure and remained high for subsequent episodes of failure. Age of 40 weeks to 1 year (at the time of the initial surgery) also proved to be an important predictor of first shunt malfunctions (HR 1.77, 95% CI 1.29-2.44). The cause of hydrocephalus was significantly associated with the risk of initial failure and, to a lesser extent, later failures. Concurrent other surgical procedures were associated with an increased risk of failure.

The patient's age at the time of initial shunt placement and the time interval since previous surgical revision are important predictors of repeated shunt failures in the multivariable model. Even after adjusting for age at first shunt insertion as well as the cause of hydrocephalus there is significant association between repeated failure times for individual patients.
Comparative neuroprotective efficacy of prolonged moderate intraischemic and postischemic hypothermia in focal cerebral ischemia
Authors: Huh Pil W. , Belayev Ludmila , Zhao Weizhao , Koch Sebastian , Busto Raul , Ginsberg Myron D.
Published: January 2008

Object

The purpose of this study was to compare the effects of prolonged hypothermia on ischemic injury in a highly reproducible model of middle cerebral artery (MCA) occlusion in rats.

Methods

Male Sprague-Dawley rats were anesthetized with halothane and subjected to 120 minutes of temporary MCA occlusion by retrograde insertion of an intraluminal nylon suture coated with poly-L-lysine through the external carotid artery into the internal carotid artery and the MCA. Two levels of prolonged postischemic cranial hypothermia (32°C and 27°C), and one level of intraischemic cranial hypothermia (32°C) were compared with the ischemic normothermia (37°C) condition. Target cranial temperatures were maintained for 3 hours and then gradually restored to 35°C over an additional 2-hour period. The animals were evaluated using a quantitative neurobehavioral battery of tests before inducing MCA occlusion, during occlusion (at 60 minutes postonset in all rats except those in the intraischemic hypothermia group), and at 24, 48, and 72 hours after reperfusion. The rat brains were perfusion fixed at 72 hours after ischemia and infarct volumes and brain edema were determined. Both intraischemic and postischemic cooling to 32°C led to similar significant reductions in cortical infarct volume (by 89 and 88%, respectively) and total infarct volume (by 54 and 69%, respectively), whereas postischemic cooling to 27°C produced lesser reductions (64 and 49%, respectively), which were not statistically significant. All three hypothermic regimens significantly lessened hemispheric swelling and improved the neurological score at 24 hours. Our data confirm that a high degree of histological neuroprotection is conferred by postischemic cooling to 32°C, which is virtually equivalent to that observed with intraischemic cooling to the same level.

Conclusions

These results may be relevant to the design of future clinical trials of therapeutic hypothermia for acute ischemic stroke.
Thoracoscopic correction and placement of anterior instrumentation for scoliotic deformity
Authors: Dickman Curtis A.
Published: January 2008

Correction of rigid scoliotic deformities involving the thoracic spine has required that a thoracotomy be performed to obtain anterior release to mobilize the deformity, as well as placement of corrective spinal instrumentation either via a separate posterior or anterior thoracic approach. To the best of the author's knowledge, this is the first published report of a case in which anterior correction of a deformity was achieved endoscopically.

A 27-year-old man presented with a rigid 85° thoracic kyphoscoliotic deformity that had developed over several years. He had previously undergone a C7-T12 laminectomy to decompress the spinal cord from a lipoma. Using thoracoscopic techniques, the author performed an anterior release and interbody fusion. Endoscopically, an anterior screw/rod system applied from T-5 to T-9 corrected the deformity to 55°.

There were no surgery-related complications. At follow-up examiniation 1.5 years after surgery, the patient had developed a solid fusion and the correction was maintained at an angle of 58°.

It is feasible to use thoracoscopic techniques to perform an anterior release and to apply anterior corrective spinal instrumentation to treat thoracic scoliotic deformities, thereby avoiding the need for an open posterior approach in which instrumentation is placed.
Retrosigmoid intradural suprameatal approach to Meckel's cave and the middle fossa: surgical technique and outcome
Authors: Samii Madjid , Tatagiba Marcos , Carvalho Gustavo A.
Published: January 2008

Object

The goal of this study was to determine whether some petroclival tumors can be safely and efficiently treated using a modified retrosigmoid petrosal approach that is called the retrosigmoid intradural suprameatal approach (RISA).

Methods

The RISA was introduced in 1983, and since that time 12 patients harboring petroclival meningiomas have been treated using this technique. The RISA includes a retrosigmoid craniotomy and drilling of the suprameatus petrous bone, which is located above and anterior to the internal auditory meatus, thus providing access to Meckel's cave and the middle fossa.

Radical tumor resection (Simpson Grade I or II) was achieved in nine (75%) of the 12 patients. Two patients underwent subtotal resection (Simpson Grade III), and one patient underwent complete resection of tumor at the posterior fossa with subtotal resection at the middle fossa. There were no deaths or severe complications in this series; all patients did well postoperatively, being independent at the time of their last follow-up examinations (mean 5.6 years). Neurological deficits included facial paresis in one patient and worsening of hearing in two patients.

Conclusions

The approach described here is a useful modification of the retrosigmoid approach, which allows resection of large petroclival tumors without the need for supratentorial craniotomies. Although technically meticulous, this approach is not time consuming; it is safe and can produce good results. This is the first report on the use of this approach for petroclival meningiomas.
Laparoscopic anterior lumbar interbody fusion
Authors: McLaughlin Mark R. , Zhang Jonathan Y. , Subach Brian R. , Haid Regis W. , Rodts Gerald E.
Published: January 2008

In recent years, there has been an unprecedented increase in the number of patients undergoing treatment with interbody fusion devices for degenerative disease of the lumbar spine. These devices can be placed either anteriorly or posteriorly. With the advent of minimally invasive surgery and the increasing ability of general surgeons to perform transperitoneal procedures laparoscopically, a new laparoscopic technique has been developed for placing lumbar interbody fusion devices. Although this procedure has some advantages over posterior lumbar interbody fusion, it is not without significant risk, and the learning curve is steep. The authors review a series of 32 consecutive patients who underwent single-level laparoscopic anterior lumbar interbody fusion at L4–5 or L5–S1 over a 2-year period for the treatment of single-level lumbar degenerative disease. In this report they review the technical aspects of the procedure and the important lessons they have learned through their early experience with this technique.