bluuebunny/crossref_metadata_2025 huggingface dataset:
Language Representation
Authors: Rutten Geert-Jan , Ramsey Nick
Published: January 2008

Dissociated language functions are largely invalidated by standard techniques such as the amobarbital test and cortical stimulation. Language studies in which magnetoencephalography (MEG) and functional magnetic resonance (fMR) imaging are used to record data while the patient performs lexicosemantic tasks have enabled researchers to perform independent brain mapping for temporal and frontal language functions (MEG is used for temporal and fMR imaging for frontal functions). In this case report, the authors describe a right-handed patient in whom a right-sided insular glioma was diagnosed. The patient had a right-lateralized receptive language area, but expressive language function was identified in the left hemisphere on fMR imaging– and MEG-based mapping. Examinations were performed in 20 right-handed patients with low-grade gliomas (control group) for careful comparison with and interpretation of this patient's results. In these tests, all patients were asked to generate verbs related to acoustically presented nouns (verb generation) for fMR imaging, and to categorize as abstract or concrete a set of visually presented words consisting of three Japanese letters for fMR imaging and MEG.

The most prominent display of fMR imaging activation by the verb-generation task was observed in the left inferior and middle frontal gyri in all participants, including the patient presented here. Estimated dipoles identified with the abstract/concrete categorization task were concentrated in the superior temporal and supra-marginal gyri in the left hemisphere in all control patients. In this patient, however, the right superior temporal region demonstrated significantly stronger activations on MEG and fMR imaging with the abstract/concrete categorization task. Suspected dissociation of the language functions was successfully mapped with these two imaging modalities and was validated by the modified amobarbital test and the postoperative neurological status. The authors describe detailed functional profiles obtained in this patient and review the cases of four previously described patients in whom dissociated language functions were found.
Brain Vasospasm After Head Injury
Authors: Bor-Seng-Shu Edson , Teixeira Manoel Jacobsen
Published: January 2008

Object.

The purpose of this prospective study was to evaluate the cumulative incidence, duration, and time course of cerebral vasospasm after traumatic brain injury (TBI) in a cohort of 299 patients.

Methods.

Transcranial Doppler (TCD) ultrasonography studies of blood flow velocity in the middle cerebral and basilar arteries (VMCA and VBA, respectively) were performed at regular intervals during the first 2 weeks posttrauma in association with 133Xe cerebral blood flow (CBF) measurements. According to current definitions of vasospasm, five different criteria were used to classify the patients: A (VMCA > 120 cm/second); B (VMCA > 120 cm/second and a Lindegaard ratio [LR] > 3); C (spasm index [SI] in the anterior circulation > 3.4); D (VBA > 90 cm/second); and E (SI in the posterior circulation > 2.5). Criteria C and E were considered to represent hemodynamically significant vasospasm. Mixed-effects spline models were used to analyze the data of multiple measurements with an inconsistent sampling rate.

Overall 45.2% of the patients demonstrated at least one criterion for vasospasm. The patients in whom vasospasm developed were significantly younger and had lower Glasgow Coma Scale scores on admission. The normalized cumulative incidences were 36.9 and 36.2% for patients with Criteria A and B, respectively. Hemodynamically significant vasospasm in the anterior circulation (Criterion C) was found in 44.6% of the patients, whereas vasospasm in the BA—Criterion D or E—was found in only 19 and 22.5% of the patients, respectively. The most common day of onset for Criteria A, B, D, and E was postinjury Day 2. The highest risk of developing hemodynamically significant vasospasm in the anterior circulation was found on Day 3. The daily prevalence of vasospasm in patients in the intensive care unit was 30% from postinjury Day 2 to Day 13. Vasospasm resolved after a duration of 5 days in 50% of the patients with Criterion A or B and after a period of 3.5 days in 50% of those patients with Criterion D or E. Hemodynamically significant vasospasm in the anterior circulation resolved after 2.5 days in 50% of the patients. The time course of that vasospasm was primarily determined by a decrease in CBF.

Conclusions.

The incidence of vasospasm after TBI is similar to that following aneurysmal subarachnoid hemorrhage. Because vasospasm is a significant event in a high proportion of patients after severe head injury, close TCD and CBF monitoring is recommended for the treatment of such patients.
Endoscope or Microscope?
Authors: Couldwell William T.
Published: January 2008

Object.

The authors compare the views afforded by the operating microscope and the endoscope in the direct endonasal extended transsphenoidal approach to the sellar, suprasellar, and parasellar regions.

Methods.

Five formalin-fixed, silicone-injected adult cadaveric heads were studied. A direct endonasal transsphenoidal approach was performed via the right nostril, pushing aside the nasal septum. The approach was performed with the microscope first, then with the endoscope. For each step (sellar, suprasellar, and clival), the exposure afforded by direct microscopic view was measured and then compared with that obtained using the endoscope. The direct endonasal approach provides a slightly off-midline view. Although the microscope provides an adequate view of the midline structures and part of the contralateral parasellar areas, the addition of the endoscope allows for a more panoramic view and permits widening of the approach in all directions.

Conclusions.

An adequate exposure of the sellar, suprasellar, and infrasellar/upper clival regions can be achieved via a simple, direct endonasal approach. From a direct endonasal route, there is a preferential visualization of the structures contralateral to the approach. The endoscope affords a more panoramic view that extends the area covered by the operating microscope.
Balloon-Assisted Coil Embolization
Authors: Gonzalez L. Fernando , McDougall Cameron G. , Albuquerque Felipe C. , Kim Louis J. , Spetzler Robert F.
Published: January 2008

Object.

The aim of this study was to assess the incidence, indications, complications, and angiography results associated with balloon-assisted coil embolization (BACE) of intracranial aneurysms and to compare these factors with those for conventional coil embolization (CE).

Methods.

Between 1995 and 2005, 827 intracranial aneurysms in 757 consecutive patients were packed with coils. Balloon-assisted coil embolization was used in 8.6% (71 of 827) of the coil insertion procedures and was more frequently used in large aneurysms, un-ruptured lesions, and those located on the vertebrobasilar system and carotid artery. Procedure-related complications leading to death or dependency were significantly higher in BACEs (14.1%) compared with those in CEs (3%). Packing densities and the results of 6-month follow-up angiography studies did not differ significantly between the two types of treatments. There was a strong trend for a higher retreatment rate in the aneurysms treated with BACE.

Conclusions.

Balloon-assisted coil embolization of intracranial aneurysms is associated with a high complication rate and should only be used if conventional CE of these lesions is impossible or has failed and if anticipated surgical risks are too high. The BACE procedure does not improve the occlusion rates of the aneurysms on follow-up evaluation.
Meningiomas of the Superior Sagittal Sinus
Authors: Chernov Mikhail
Published: January 2008

Object.

Radical removal of meningiomas involving the major dural sinuses remains controversial. In particular, whether the fragment invading the sinus must be resected and whether the venous system must be reconstructed continue to be issues of debate. In this paper the authors studied the effects, in terms of tumor recurrence rate as well as morbidity and mortality rates, of complete lesion removal including the invaded portion of the sinus and the consequences of restoring or not restoring the venous circulation.

Methods.

The study consisted of 100 consecutive patients who had undergone surgery for meningiomas originating at the superior sagittal sinus in 92, the transverse sinus in five, and the confluence of sinuses in three. A simplified classification scheme based on the degree of sinus involvement was applied: Type I, lesion attachment to the outer surface of the sinus wall; Type II, tumor fragment inside the lateral recess; Type III, invasion of the ipsilateral wall; Type IV, invasion of the lateral wall and roof; and Types V and VI, complete sinus occlusion with or without one wall free, respectively. Lesions with Type I invasion were treated by peeling the outer layer of the sinus wall. In cases of sinus invasion Types II to VI, two strategies were used: a nonreconstructive (coagulation of the residual fragment or global resection) and a reconstructive one (suture, patch, or bypass). Gross-total tumor removal was achieved in 93% of cases, and sinus reconstruction was attempted in 45 (65%) of the 69 cases with wall and lumen invasion. The recurrence rate in the study overall was 4%, with a follow-up period from 3 to 23 years (mean 8 years). The mortality rate was 3%, all cases due to brain swelling after en bloc resection of a Type VI meningioma without venous restoration. Eight patients—seven of whom harbored a lesion in the middle third portion of the superior sagittal sinus—had permanent neurological aggravation, likely due to local venous infarction. Six of these patients had not undergone a venous repair procedure.

Conclusions.

The relatively low recurrence rate in the present study (4%) favors attempts at complete tumor removal, including the portion invading the sinus. The subgroup of patients without venous reconstruction displayed statistically significant clinical deterioration after surgery compared with the other subgroups (p = 0.02). According to this result, venous flow restoration seems justified when not too risky.
Gamma Knife surgery for trigeminal schwannoma
Authors: Sheehan Jason , Yen Chun Po , Arkha Yasser , Schlesinger David , Steiner Ladislau
Published: January 2008

Object

Trigeminal schwannomas are rare intracranial tumors. In the past, resection and radiation therapy were the mainstays of their treatment. More recently, neurosurgeons have begun to use radiosurgery in the treatment of trigeminal schwannomas because of its successful use in the treatment of vestibular schwannomas. In this article the authors evaluate the radiological and clinical outcomes in a series of patients in whom Gamma Knife surgery (GKS) was used to treat trigeminal schwannomas.

Methods

Twenty-six patients with trigeminal schwannomas underwent GKS at the University of Virginia Lars Lek-sell Gamma Knife Center between 1989 and 2005. Five of these patients had neurofibromatosis and one patient was lost to follow up. The median tumor volume was 3.96 cm3, and the mean follow-up period was 48.5 months. The median prescription radiation dose was 15 Gy, and the median prescription isodose configuration was 50%. There was clinical improvement in 18 patients (72%), a stable lesion in four patients (16%), and worsening of the disease in three patients (12%). On imaging, the schwannomas shrank in 12 patients (48%), remained stable in 10 patients (40%), and increased in size in three patients (12%). These results were comparable for primary and adjuvant GKSs. No tumor growth following GKS was observed in the patients with neurofibromatosis.

Conclusions

Gamma Knife surgery affords a favorable risk-to-benefit profile for patients harboring trigeminal schwannomas. Larger studies with open-ended follow-up review will be necessary to determine the long-term results and complications of GKS in the treatment of trigeminal schwannomas.
Neurokinin-1 receptor antagonism in a rat model of subarachnoid hemorrhage: prevention of upregulation of contractile ETB and 5-HT1B receptors and cerebral blood flow reduction
Authors: Ansar Saema , Svendgaard Niels-Aage , Edvinsson Lars
Published: January 2008

Object

Cerebral vasospasm following subarachnoid hemorrhage (SAH) leads to reduced cerebral blood flow (CBF) and to cerebral ischemia, in some cases even producing infarction and long-term disability. The goal of the present study was to investigate the hypothesis that inhibition of neurokinin-1 receptors (NK1Rs) by administration of L-822429 blunts the decrease in CBF as well as cerebrovascular receptor upregulation in an animal model of SAH.

Methods

Subarachnoid hemorrhage was induced in rats by injection of 250 μl of blood into the prechiasmatic cistern. The NK1R inhibitor L-822429 was injected intracisternally 30 minutes and 24 hours after the induction of SAH. Two days after SAH induction, the basilar arteries were harvested, and contractile responses to endothelin-1 (ET-1, an ETA- and ETB-receptor agonist) and 5-carboxamidotryptamine (a 5-hydroxytryptamine-1 [5-HT1]-receptor agonist) were investigated using sensitive myographs. To determine whether NK1R inhibition had an influence on local CBF after post-SAH, a quantitative autoradiographic technique was used.

After SAH, the vascular receptor phenotype was changed in cerebral arteries through upregulation of contractile ETB and 5-HT1B receptors, while regional and total CBF were markedly reduced. Treatment with the selective NK1R inhibitor L-822429 prevented both the receptor upregulation and the reduction in regional and global CBF.

Conclusions

The data reveal the coregulation of vascular receptor changes and blood flow effects, and also show that interaction with a small-molecule NK1R antagonist is a promising area of focus for the development of specific treatments for SAH.
Surgical anatomy and landmarks for the basal vein of Rosenthal
Authors: Tubbs R. Shane , Loukas Marios , Louis Robert G. , Shoja Mohammadali M. , Askew Cameron S. , Phantana-Angkool April , Salter E. George , Oakes W. Jerry
Published: January 2008

Object

The basal vein of Rosenthal (BV) courses from the premesencephalic cistern, through the ambient cistern, and terminates in the quadrigeminal cistern. The aim of this study was to describe and quantitate the surgical anatomy of this structure and specifically to provide landmarks for identifying this vessel along its course. These data may be of use, for example, to surgeons using subtemporal operative approaches through regions where this vessel is concealed.

Methods

The authors examined 15 latex-injected adult cadaveric brains (30 sides) to delineate the morphological characteristics of the BV. Dissections of the BV were then performed and measurements were made between this structure and the tentorial incisura at the anterior, middle, and posterior borders of the lateral midbrain.

All specimens were found to have a left and right BV with varying morphological characteristics. The mean distance between the BV and posterior cerebral artery at the midpoint of the lateral midbrain was 16 mm. The BV was always found superomedial to the posterior cerebral artery along the lateral aspect of the midbrain, and the BV ranged in diameter from 1 to 5 mm. The BV drained into the vein of Galen in all but two specimens. The mean distances from the tentorial edge to the BV at the anterior, middle, and posterior borders of the lateral midbrain were 11, 13, and 4 mm, respectively. No statistically significant differences were found when comparing left and right sides or male and female specimens.

Conclusions

The authors hope that these data will help the neurosurgeon operating near the BV to avoid injury to this important structure.
Combined transarterial N-butyl cyanoacrylate and coil embolization of direct carotid–cavernous fistulas
Authors: Troffkin Neil A. , Given Curtis A.
Published: January 2008

✓ The authors report two cases of traumatic carotid–cavernous fistulas treated successfully with combined N-butyl cyanoacrylate glue and coil embolization via a transarterial approach. In both cases complete occlusion of the fistula was achieved, with preservation of the parent carotid artery. Casting of the cavernous sinus with a liquid embolic agent was well tolerated and produced no complications of cranial nerve palsy. This technique provides interventionalists with yet another treatment option in these often complex cases.
Transcranial puncture through the parietal and mastoid foramina for the treatment of dural fistulas
Authors: Chapot René , Saint-Maurice Jean-Pierre , Narata Ana Paula , Rogopoulos André , Moreau Jean-Jacques , Houdart Emmanuel , Maubon Antoine
Published: January 2008

✓ In this report the authors describe the endovascular treatment of dural arteriovenous fistulas (DAVFs) through trans-cranial puncture of the feeding arteries. Four patients had DAVFs that were fed by occipital arteries (OAs) that supplied blood to the intracranial meningeal arteries via the transcranial branches and coursed through the parietal and mastoid foramina. Due to the excessive tortuosity of the OA, conventional endovascular navigation had failed in all cases. Transcranial puncture of the meningeal feeding arteries was performed through the parietal or mastoid foramen, allowing navigation with a microcatheter until the level of the shunts. Complete cure of the DAVF was attained in all patients after injection of acrylic glue.
An adjustable nasal speculum for the extended transsphenoidal approach
Authors: Kitano Masahiko , Taneda Mamoru
Published: January 2008

✓The authors describe a newly modified nasal speculum that enables panoramic visualization of the deep and wide surgical field created via an extended transsphenoidal approach. In their approach, the bone around the piriform aperture is not removed.
Safety and efficacy of the porcine small intestinal submucosa dural substitute: results of a prospective multicenter study and literature review
Authors: Bejjani Ghassan K. , Zabramski Joseph , _ _
Published: January 2008

Object

Dural substitutes are often needed after neurosurgical procedures to expand or replace dura mater resected during surgery. A new dural repair material derived from porcine small intestinal submucosa (SIS) was evaluated in a prospective multicenter clinical study.

Methods

Between 2000 and 2003, 59 patients at five different institutions underwent dural reconstruction with the SIS dural substitute, with a minimum follow up of 6 months. The primary goals of the study were to assess the efficacy and safety of the SIS dural substitute according to the rate of cerebrospinal fluid (CSF) leakage, infection, and meningitis.

Chiari malformation Type I decompression (32 patients) and tumor resection (18 patients) were the most common procedures performed, with 81% of SIS grafts implanted in the posterior fossa or spine. There was one case of a CSF leak (1.7%), two cases of wound infection (3.4%), and no cases of bacterial meningitis (0%) in the 58 patients available for follow up. In both cases of wound infection, the SIS graft acted as a barrier to infection and was not removed. Intraoperatively, a watertight seal was achieved in all 59 cases. On follow-up imaging available in 27 patients there was no evidence of any adverse reaction to the graft or of cerebral inflammation.

Conclusions

The SIS dural substitute demonstrated substantial efficacy in these patients after a mean follow up of 7.3 ± 2.2 months. Rates of infection, CSF leakage, and meningitis were comparable to those reported for other dural substitute materials. A lack of adverse reactions to the graft, favorable safety profile, and clinical efficacy all point to the utility of this material as an alternative for dural repair.
In vivo transcranial brain surgery with an ultrasonic time reversal mirror
Authors: Pernot Mathieu , Aubry Jean-Francois , Tanter Mickael , Boch Anne-Laure , Marquet Fabrice , Kujas Michele , Seilhean Danielle , Fink Mathias
Published: January 2008

Object

High-intensity focused ultrasonography is known to induce controlled and selective noninvasive destruction of tissues by focusing ultrasonic beams within organs, like a magnifying glass concentrating enough sunlight to burn a hole in paper. Such a technique should be highly interesting for the treatment of deep-seated lesions in the brain. Nevertheless, ultrasonic tissue ablation in the brain has long been hampered by the defocusing effect of the skull bone.

Methods

In this in vivo study, the authors used a high-power time-reversal mirror specially designed for noninvasive ultrasonic brain treatment to induce thermal lesions through the skulls of 10 sheep. The sheep were divided into three groups and, depending on group, were killed 1, 2, or 3 weeks after treatment. The thermal lesions were confirmed based on findings of posttreatment magnetic resonance imaging and histological examinations.

After treatment, the basic neurological functions of the animals were unchanged: the animals recovered from anesthesia without any abnormal delay and did not exhibit signs of paralysis or coma. No major behavioral change was observed.

Conclusions

The results provide striking evidence that noninvasive ultrasonographic brain surgery is feasible. Thus the authors offer a novel noninvasive method of performing local brain ablation in animals for behavioral studies. This technique may lead the way to noninvasive and nonionizing treatment of brain tumors and neurological disorders by selectively targeting intracranial lesions. Nevertheless, sheep do not represent a good functional model and extensive work will need to be conducted preferably on monkeys to investigate the effects of this treatment.
Spontaneous adrenal hemorrhage: a little-known complication of intracranial tumor surgery
Authors: Gutenberg Angelika , Lange Bettina , Gunawan Bastian , Larsen Joerg , Brück Wolfgang , Rohde Veit , Verheggen Raphaela
Published: January 2008

✓ Nontraumatic adrenal hemorrhage in adults is uncommon and unexpected in the context of intracranial surgery. The authors report on a patient in whom hemodynamically relevant retroperitoneal bleeding developed within hours after an otherwise uneventful operation for a falcine meningioma. In this brief report they seek to draw attention to this rare but life-threatening complication, because rapid diagnosis can be life-saving.
Cerebellopontine angle meningeal melanocytoma: a rare tumor in an uncommon location
Authors: Gupta Aditya , M.Ch.  , Ahmad Faiz U. , Sharma Mehar C. , Garg Ajay , Mehta Veer S.
Published: January 2008

✓Meningeal melanocytomas are uncommon intracranial tumors and their occurrence at the cerebellopontine angle (CPA) is extremely rare. The authors describe the case of a 58-year-old woman who presented with a left CPA tumor; on the basis of histopathological studies after resection, a diagnosis of meningeal melanocytoma was reached. The relevant literature is reviewed.
Pain and Craniotomy
Authors: Kincaid M. Sean , Lam Arthur M.
Published: January 2008

Object

Opioid administration after major intracranial surgery is often limited by a presumed lack of need and a concern that opioids will adversely affect the postoperative neurological examination. The authors conducted a prospective study to evaluate the incidence, severity, and treatment of postoperative pain in patients who underwent major intracranial surgery.

Methods

One hundred eighty-seven patients (77 men and 110 women, mean age 52 ± 15 years, mean weight 78.1 ± 19.9 kg) underwent either supratentorial (129 patients) or infratentorial (58 patients) procedures. Sixty-nine percent of the patients reported experiencing moderate to severe pain (≥ 4 on a 0–10 scale) during the 1st postoperative day. Pain scores greater than or equal to 4 persisted in 48% on the 2nd postoperative day. Approximately 80% of patients were treated with acetaminophen on the 1st postoperative day, whereas opioids (primarily intravenous fentanyl) were administered to 58%. Compared with patients who underwent supratentorial procedures, those who underwent infratentorial procedures reported more severe pain at rest (mean score 4.9 ± 2.2 compared with 3.8 ± 2.6; p = 0.015) and with movement (mean score 6.3 ± 2.6 compared with 4.5 ± 2.7; p <0.001) on the 1st postoperative day. On both the 1st and 2nd postoperative days, patients who underwent infratentorial procedures received greater quantities of opioid (p ≤ 0.019) and nonopioid (p ≤ 0.013) analgesics than those who underwent supratentorial procedures. Patients' dissatisfaction with analgesic therapy was significantly associated with elevated pain levels on the first 2 postoperative days (p <0.001).

Conclusions

In contrast to prevailing assumptions, the study findings reveal that most patients undergoing elective major intracranial surgery will experience moderate to severe pain for the first 2 days after surgery and that this pain is often inadequately treated.
How does the participation of a resident surgeon in procedures for small intracranial aneurysms impact patient outcome?
Authors: Morgan Michael K. , Assaad Nazih N. , Davidson Andrew S.
Published: January 2008

Object

In this paper the authors' goal was to evaluate whether resident neurosurgeons participating in entry-level aneurysm surgery have a negative impact on patient outcomes.

Methods

The authors searched the database for entry-level aneurysm surgeries (that is, those ≤ 10 mm and located in the internal carotid artery [beyond the paraclinoid segment] and middle cerebral artery) performed in 1991 through 2005. The presence or absence of an advanced resident (in his/her last 3 years of residency) was noted. The analysis was examined in 3-year quintiles.

A total of 355 cases (196 with resident participation and 159 without) were evaluated. Permanent adverse outcomes were seen in 11 patients (3.1% of the total study population), all due to branch artery occlusion. The incidence of permanent adverse outcomes in the first 3 years was 10.7% and 2.4% thereafter. This difference was statistically significant (p = 0.015). There was no difference in the incidence of adverse outcomes when comparing surgery performed with and without participation of an advanced resident.

Conclusions

In this study the authors have demonstrated a learning curve in this series of patients. This study also suggests that involving residents in the repair of small unruptured aneurysms will not compromise patient care. In addition, patients can be informed that the team approach to their surgery is at least as good as having the experienced surgeon performing all aspects of the surgery.
Hemorrhage after particle embolization of hemangioblastomas: comparison of outcomes in spinal and cerebellar lesions
Authors: Cornelius Jan Frédérick , Saint-Maurice Jean Pierre , Bresson Damien , George Bernard , Houdart Emmanuel
Published: January 2008

Object

In this study the authors compare the clinical outcomes after particle embolization of hemangioblastomas in the cerebellum and spinal cord. They also review the literature of similar cases.

Methods

Seven patients with hemangioblastomas in the spinal cord (four patients) and cerebellum (three patients) underwent preoperative embolization at the authors' center. Magnetic resonance imaging and selective angiography studies as well as histological diagnoses were available in all patients. Embosphere particles (trisacryl gelatin microspheres) were used in all cases. The smallest particle diameter ranged from 100 to 300 μm at the beginning of embolization in all patients.

The outcome of embolization was favorable in patients with spinal cord hemangioblastomas, but it was unfavorable for those with cerebellar hemangioblastomas; acute tumor bleeding and death occurred in all of the latter cases. The outcomes following embolization are very different for these two locations possibly because of the different capillary sizes.

Conclusions

The authors no longer use particle embolization to treat cerebellar hemangioblastomas.
Comparison of anterior- and posterior-approach instrumented lumbar interbody fusion for spondylolisthesis
Authors: Min Jun-Hong , Jang Jee-Soo , Lee Sang-Ho
Published: January 2008

Object

The purpose of this study was to compare the imaging and clinical outcomes obtained in patients with lumbar spondylolisthesis who have undergone either instrumented anterior lumbar interbody fusion (ALIF) or instrumented posterior LIF (PLIF), especially with regard to the development of adjacent-segment degeneration (ASD).

Methods

Forty-eight patients with preoperative spondylolisthesis and minimal ASD who underwent instrumented L4–5 fusion were divided into two groups according to the surgical approach. After ensuring the two groups' comparability, the following variables were evaluated: postoperative segmental and lumbar lordosis, postoperative percentage of vertebral slippage, reduction rate, incidence of ASD, and clinical outcomes.

Results

Adjacent-segment degeneration was found in 44.0% of the patients in the ALIF group and in 82.6% of those in the PLIF group (p = 0.008). Clinical success rates were 92.0 and 87.0% in the ALIF and PLIF groups, respectively. There were no statistically significant intergroup differences in the postoperative segmental and lumbar lordosis, postoperative percentage of slippage, reduction rate, Japanese Orthopaedic Association score, and success rate.

Conclusions

Both ALIF and PLIF can produce good outcomes in treating lumbar spondylolisthesis, but ALIF is more advantageous in preventing the development of ASD.
Clinical significance of the redundant nerve roots of the cauda equina documented on magnetic resonance imaging
Authors: Ono Atsushi , Suetsuna Futoshi , Irie Tomoyuki , Yokoyama Toru , Numasawa Takuya , Wada Kanichiro , Toh Satoshi
Published: January 2008

Object

Previous reports of redundant nerve roots (RNRs) of the cauda equina have been limited to evaluations based on myelography. Neither the imaging nor the clinical features of RNRs in relation to magnetic resonance (MR) imaging have been elaborated. The MR imaging characteristics of RNRs were evaluated using the Japanese Orthopaedic Association score before and after the surgery.

Methods

There were 44 patients with L4–5 spondylolisthesis in which a complete blockage was demonstrated on myelography. All patients underwent posterior L4–5 interbody fusion. Based the myelographic and MR imaging findings, the patients were stratified into the following three groups: RNRs recognized on both myelographic and MR imaging (Group A); RNRs recognized on myelography but not very evident on MR imaging (Group B); and RNRs not recognized on either myelographic or MR imaging (Group C). Among these three groups, pre- and postoperative clinical symptoms were compared.

Results

There were 16 patients in Group A, 14 in Group B, and 14 in Group C. In terms of preoperative clinical symptoms, there was a significant difference between Groups A and C in the incidence of leg pain and tingling sensation. Significant differences were also noted between Groups A and C and between Groups B and C in ambulatory ability. Evaluation of postoperative clinical symptoms showed a significant difference between Groups A and C in ambulatory ability.

Conclusions

Patients with MR imaging evidence of RNRs presented with more severe clinical symptoms. It is believed that the RNR features derived from MR images represent important findings.
Percutaneous surgical treatment of Chance fractures using cannulated pedicle screws
Authors: Schizas Constantin , Kosmopoulos Victor
Published: January 2008

✓Chance fractures are relatively rare injuries and can be treated either conservatively, with a cast, or surgically, especially when posterior ligament injury is present. This paper presents two cases of lumbar Chance fractures treated using recently developed percutaneous cannulated pedicle screws. The first patient suffered associated abdominal injuries that required surgery, while the second had associated stable spinal fractures. Intraoperative blood loss was minimal. Both patients progressed to osseous union without implant failure. Following minimally invasive implant removal 9 months after injury, both patients remained asymptomatic without any evidence of instability on flexion and extension images obtained during their latest follow-up. This technique may be useful in selected cases in which bone grafting is not necessary; it allows early mobilization and stable fixation while minimizing morbidity.
Rapidly progressive paraplegia due to an extradural lumbar meningocele mimicking a cyst
Authors: Fiss Ingo , Danne Marco , Hartmann Christian , Brock Mario , Stendel Ruediger
Published: January 2008

✓Unlike arachnoid meningoceles, arachnoid cysts frequently cause local pressure effects probably because there is no free communication between the cyst and the subarachnoid space. Following the first detailed description of cystic lesions of spinal nerve roots by Tarlov in 1938, a simplified classification of spinal meningeal cysts was developed in 1988, containing three major categories. The authors report on a lumbar intraspinal extradural meningocele that caused incomplete paraplegia in an otherwise healthy 31-year-old man in whom magnetic resonance imaging revealed stigmata of Scheuermann disease. Intraoperatively, the lesion was classified as a transitional-type lesion, in accordance with Type IA of the Nabors classification, because a communication with the subarachnoid space was observed. After complete removal of the meningocele, the patient's recovery was prompt and complete.
Computed tomography–guided percutaneous facet screw fixation in the lumbar spine
Authors: Kang Ho Yeong , Lee Sang-Ho , Jeon Sang Hyeop , Shin Song-Woo
Published: January 2008

✓ The authors describe a new minimally invasive technique for posterior supplementation using percutaneous trans-laminar facet screw (TFS) fixation with computed tomography (CT) guidance. Oblique axial images were used to determine facet screw fixation sites. After the induction of local anesthesia and conscious sedation, a guide pin was inserted and guided with a laser mounted on the CT gantry. Cannulated TFSs were placed via a percutaneous approach. From December 2002 to August 2003, 18 patients underwent CT-guided TFS. In 17 of these patients this procedure was supplementary to anterior lumbar interbody fusion, which had been performed several days earlier; in the remaining patient, CT-guided TFS fixation was undertaken as the primary therapy. Twelve patients had painful degenerative disc disease or unstable degenerative spondylolisthesis, three had infections, and three had deformities. All screws were inserted accurately and there were no complications. This new minimally invasive surgical technique may offer an alternative to pedicle screw fixation as a method of posterior supplementation.
Palliative dual iliac screw fixation for lumbosacral metastasis
Authors: Fujibayashi Shunsuke , Neo Masashi , Nakamura Takashi
Published: January 2008

✓ Spinal fixation for destructive metastatic lesions at the lumbosacral junction is challenging because of the large and unique load-bearing characteristics present. In particular, caudal fixation is difficult in cases of sacral destruction because of insufficient S-1 pedicle screw anchorage. The authors describe their surgical technique for secure iliac screw placement and the clinical results obtained in five patients with metastatic spinal disease. All patients in this study underwent palliative operations with dual iliac screw fixation between April 1999 and October 2002, and the clinical and radiological findings were assessed. In all five patients, spinal metastases extended into the sacrum. The metastases were from renal cell carcinomas in two patients, lung cancer in two, and a paraganglioma in one patient.

Postoperative follow-up periods ranged from 3 months to 6 years (mean 28.4 months). Preoperatively, four patients could not walk due to severe pain or neurological compromise. Postoperatively, all patients reported a reduction in pain and regained the ability to walk. Complications included one case of early wound infection. In the patients with long survival after the operation, there was one case of iliac screw loosening and one case of rod breakage. The dual iliac screw fixation technique provided sufficient immediate stability for destructive lumbosacral metastasis.
Occipitocervical fusion with rigid internal fixation: long-term follow-up data in 69 patients
Authors: Nockels Russ P. , Shaffrey Christopher I. , Kanter Adam S. , Azeem Syed , York Julie E.
Published: January 2008

Object.

Instability of the occipitocervical junction may result from degenerative disease, infection, tumor, and trauma. Surgical stabilization involving screw fixation and rigid implants has been found to be biomechanically superior to wire-based implants. To evaluate the long-term results in a large and diverse patient population, the authors prospectively studied a consecutive group of 69 patients.

Methods.

All patients underwent occipitocervical fusion in which rigid posterior instrumentation included either plates or rods and screws. Patients ranged in age from 11 to 90 years (mean 51.4 years); there were 34 female and 35 male patients. The mean follow-up duration was 37 months (range 6–66 months). Fifty-seven (83%) of the 69 patients had long-standing occipitocervical anomalies, whereas the remainder presented with acute instability. Basilar invagination was present in 20 patients.

Results.

Correction of a severe cervical kyphotic deformity was accomplished in six patients. There were no fatalities or medical complications associated with the procedures. During the follow-up period, 87% of the patients exhibited improvement in their myelopathic symptoms; in 13% the symptoms were unchanged. Complications were minimal. Stability was demonstrated on flexion/extension studies in all cases. There were no treatment-related deaths, although four patients died within the follow-up period, all due to progression of metastatic disease.

Conclusions.

The authors found that rigid internal fixation of the occipitocervical complex was safe, effective, and technically possible for spine surgeons familiar with occipital bone anatomy and lateral mass fixation.
Wear simulation of the ProDisc-L disc replacement using adaptive finite element analysis
Authors: Rawlinson Jeremy J. , Punga Karan P. , Gunsallus Kirk L. , Bartel Donald L. , Wright Timothy M.
Published: January 2008

Object.

An understanding of the wear potential of total disc replacements (TDRs) is critical as these new devices are increasingly introduced into clinical practice. The authors analyzed the wear potential of a ProDisc-L implant using an adaptive finite element (FE) technique in a computational simulation representing a physical wear test.

Methods.

The framework for calculating abrasive wear, first validated using a model of a total hip replacement (THR), was then used to model the ProDisc-L polyethylene component that is fixed to the inferior endplate and articulates with the rigid superior endplate. Proposed standards for spine wear testing protocols specified the inputs of flexion–extension (6/−3°), lateral bending (± 2°), axial twist (± 1.5°), and axial load (200–1750 N or 600–2000 N) applied to the model through 10 million simulation cycles. The model was calibrated with a wear coefficient determined from an experimental wear test. Implicit FE analyses were then performed for variations in coefficient of friction, polyethylene elastic modulus, radial clearance, and polyethylene component thickness to investigate their effects on wear.

Results.

Using the initial loading protocol (single-peaked axial load profile of 300–1750 N) from the experimental wear test, the polyethylene wear rate was 9.82 mg per million cycles. When a double-peaked loading profile (600–2000 N) was applied, the wear rate increased to 11.77 mg per million cycles. Parametric design variations produced only small changes in wear rates for this simulation.

Conclusions.

The chosen design variables had little effect on the resultant wear rates. The comparable wear rate for the THR validation analysis was 16.17 mg per million cycles, indicating that, using this framework, the wear potential of the TDR was equivalent to, if not better, than the THR using joint-specific loading standards.
Local delivery of OncoGel delays paresis in rat metastatic spinal tumor model
Authors: Bagley Carlos A. , Bookland Markus J. , Pindrik Jonathan A. , Ozmen Tolga , Gokaslan Ziya L. , Witham Timothy F.
Published: January 2008

Object.

Spinal column metastatic disease clinically affects thousands of cancer patients every year. Local chemotherapy represents a new option in the treatment of metastatic disease of the spine. Despite the clinical impact of metastatic spine disease, the literature currently lacks an accurate animal model for the effective dosing of local chemotherapeutic agents within the vertebral column.

Methods.

Female Fischer 344 rats, weighing 150 to 200 g each, were used in this study. After induction of anesthesia, a transabdominal approach to the ventral vertebral body of L-6 was performed. A small hole was drilled and 5 μL of ReGel (blank polymer), OncoGel (paclitaxel and ReGel) 1.5%, OncoGel 3.0%, or OncoGel 6.0% were immediately injected to determine drug toxicity. Based on these results, efficacy studies were performed by intratumoral injection of 5 μL of ReGel, OncoGel 3.0%, and OncoGel 6.0% on Day 6 in a CRL-1666 breast adenocarcinoma metastatic spine tumor model. Hind limb function was tested pre- and postoperatively using the Basso-Beattie-Bresnahan rating scale. Histological analysis of the spinal cord and vertebral column was performed when the animal died or was killed.

Results.

There were no signs of toxicity observed in association with any of the agents under study. No increased benefit was seen in the blank polymer group compared with the control group (tumor only). OncoGel 3.0% and OncoGel 6.0% were effective in delaying the onset of paralysis in the respective study groups.

Conclusions.

These findings demonstrate the potential benefit of OncoGel in cases of subtotal resections of metastatic spinal column tumors. OncoGel 6.0% is the most efficacious drug concentration and offers the best therapeutic option in this experimental model. These results provide promise for the development of local chemotherapeutic means to treat spinal metastases.
A comparison of single and incremental impact approaches for producing experimental thoracolumbar burst fractures
Authors: Wang Xiang-Yang , Dai Li-Yang , Xu Hua-Zi , Chi Yong-Long
Published: January 2008

Object.

Experimental burst fracture models are often developed by using either single or incremental impacts. In both protocols, the weight-drop technique produces the impact. However, to the authors' knowledge in no study have researchers attempted to compare the equivalence of the spine burst fracture produced using the different impact protocols. This study was performed to investigate whether the single and incremental trauma approaches produce equivalent degrees of severity in thoracolumbar burst fractures.

Methods.

Twenty bovine thoracolumbar spines comprising three vertebrae were divided evenly into the single impact and incremental impact groups. The specimens in the incremental impact group were subjected to three axial compressive impacts of increasing energy (78.4, 107.8, and 137.2 J), whereas specimens in the other group were subjected to a single impact (137.2 J). Before and after the final trauma, multidirectional flexibility of each specimen was measured under flexion/extension, right/left lateral bending, and right/left axial rotation, thus quantifying the instability of the fracture. The flexibility parameters were then compared between the two groups.

Results.

A significant increase in flexibility parameters was found after the final trauma in both groups, indicating the instability of the spine (p < 0.01). No significant differences in flexibility parameters were observed in either intact status or injured status between the two groups (p > 0.05).

Conclusions.

In this study the authors have confirmed that the single and incremental impact protocols produced a similar degree of severity in producing an in vitro bovine burst fracture. The results of this study support the use of the incremental impact protocol in future experimental biomechanical studies.
Use of intraoperative sodium tetradecyl sulfate for the treatment of a spinal epidural hemangioma
Authors: Baig Mirza N. , Saquib Syed , Christoforidis Greg , Caragine Louis P.
Published: January 2008

✓Spinal hemangiomas can be categorized into three different groups based on location. Vertebral body (VB) heman-giomas are frequent incidental findings on magnetic resonance (MR) imaging. There is a subdivision of these with spinal epidural extension that have been reported in the literature. Spinal hemangiomas can also be epidural without VB involvement; these are extremely rare with few reported cases in the thoracic epidural spinal column. The diagnosis and imaging characteristics as well as the surgical tools used in gross-total resection of spinal epidural hemangioma are not well understood.

The authors present a detailed characterization of a spinal epidural hemangioma in a 30-year-old woman who presented with complaints of gradual onset of low-back pain that worsened over 1 year. The MR imaging findings indicated a large L2–S1 epidural spinal mass causing thecal sac compression. The patient underwent an L2–S1 laminectomy, and a vascular extradural mass was noted on the posterior aspect of the dura mater. Preoperative spinal angiography as well as intraoperative angiography was performed.

Total resection of the tumor was achieved using intraoperative embolization with sodium tetradecyl sulfate and microscopic dissection. The postoperative MR imaging findings and clinical outcome were excellent.

The findings and use of sodium tetradecyl sulfate in gross-total resection are discussed. The authors also review treatment modalities and demonstrate the utility and effectiveness of intraoperative sodium tetradecyl sulfate in gross-total resection of large difficult spinal epidural hemangiomas.
Tethering tracts in spina bifida occulta: revisiting an established nomenclature
Authors: Rajpal Sharad , Salamat M. Shahriar , Tubbs R. Shane , Kelly David R. , Oakes W. Jerry , Iskandar Bermans J.
Published: January 2008

Object

The goal of the present study goal was to systematically confirm the previously recognized nomenclature for tethering tracts that are part of the spectrum of occult spinal dysraphic lesions.

Methods

The tethering tract in 20 patients with spina bifida occulta underwent histological examination with H & E staining and epithelial membrane antigen (EMA) immunolabeling, and additional selected specimens were stained with Masson trichrome.

Results

All tethering tracts contained fibrous connective tissue. Four tracts were lined with epithelial cells and either originated within a dermoid cyst, terminated at a skin dimple/sinus opening, or had both of these characteristics. No tethering tracts exhibited EMA positivity or meningeal elements. Although all tethering tracts originated in juxtaposition to the spinal cord, their termination sites were variable.

Conclusions

Based on histological findings and presumed embryological origin, the authors broadly classified tethering tracts terminating within the dura mater, epidural space, or lamina as “short tethering tracts” (STTs). The STTs occurred mostly in conjunction with split cord malformations and had a purely fibrous composition. Tethering tracts terminating superficial to the overlying lamina were classified as “long tethering tracts” (LTTs), and the authors propose that these are embryologically distinct from STTs. The LTTs were of two varieties: epithelial and nonepithelial, the former being typically associated with a skin dimple or spinal cord (epi)dermoid cyst. In fact, analysis of the data suggested that not every tethering tract terminating in or on the skin should be classified as a dermal sinus tract without histological confirmation, and because no evidence of meningeal tissue–lined tracts was detected, the use of the term “meningocele manqué” may not be appropriate.