bluuebunny/crossref_metadata_2025 huggingface dataset:
Proton radiosurgery in neurosurgery
Authors: Chen Clark C. , Chapman Paul , Petit Joshua , Loeffler Jay
Published: December 2007

Object

Photon energy deposition from gamma or photon sources follows the law of exponential decay. Consequently, energy is deposited over the entire path of the radiation beam, resulting in dose distribution before and after the target is reached. In contrast, the physical properties of protons are such that energy deposition occurs with no exit dose beyond the target volume. Therefore, relative to photons, proton beams represent a superior platform for the administration of radiosurgery.

Methods

In this review, the authors will discuss the fundamental principles underlying photon- and proton-based stereotactic radiosurgery (SRS). The clinical efficacy of proton-based SRS in the treatment of arteriovenous malformations, vestibular schwannomas, and pituitary adenomas is reviewed.

Results

Direct comparisons of clinical results attained using photon- and proton-based SRS are confounded by a bias toward reserving proton beams for the treatment of larger and more complex lesions. Despite this bias, the clinical outcomes for proton-based SRS have been excellent and have been at least comparable to those for photon-based treatments.

Conclusions

The physical properties of proton radiation offer superior conformality in dose distribution relative to photon irradiation. This advantage becomes more apparent as the lesion size increases and will probably be magnified with the development of intensity-modulated proton techniques.
Robotics and its applications in stereotactic radiosurgery
Authors: Jayarao Mayur , Chin Lawrence S.
Published: December 2007

✓ Stereotactic radiosurgery has undergone a remarkable evolution since its conception and the subsequent introduction of image-guided radiosurgery, primarily because of the concurrent advances in imaging and computer technology. However, recent improvements in real-time imaging, inverse planning techniques, and frameless alternatives have greatly enhanced the conformity and accuracy of the radiosurgical procedure. As a consequence, the possibility of hypofractionation is offered, and both intra- and extracranial targets can now be ablated with sustained submillimetric precision. Although all indispensable features, none is as impressive or useful as the incorporation of robotics, robotic beam delivery, or robotic-assisted planning, which has only served to improve the accuracy and homogeneity of therapy. The aim of this article was to describe the general technological basis of robots in radiosurgery and to review current clinical usage of robotic radiosurgery devices. Emphasis has been placed on robotic principles and the various popular applications currently available.
Gamma Knife stereotactic radiosurgical treatment of idiopathic trigeminal neuralgia: long-term outcome and complications
Authors: Fountas Kostas N. , Smith Joseph R. , Lee Gregory P. , Jenkins Patrick D. , Cantrell Rebecca R. , Sheils W. Chris
Published: December 2007

Object

Stereotactic radiosurgery (SRS) with the Gamma Knife (GK) is a rapidly emerging surgical modality in the management of medically refractory idiopathic trigeminal neuralgia (TN). The current study examines the long-term outcome in patients with drug-resistant idiopathic TN who underwent GK surgery at the authors‘ institution.

Methods

One hundred and six consecutive patients (38 men and 68 women) with proven medically refractory idiopathic TN were included in this retrospective study. Their ages were 41–82 years (mean 72.3 years). All patients underwent SRS with prescribed maximal radiation doses ranging from 70 to 85 Gy. Isocenters 1–3 were used and plugging was used selectively. The follow-up period was 12–72 months (mean 34.3 months). The patients were divided into 2 groups according to their history of previous surgery.

Results

The initial response rate in patients with no history of previous surgery was 92.9%; in those who had undergone previous surgery, the initial response rate was 85.7%. At the end of the 1st posttreatment year, an excellent outcome was achieved in 82.5% of patients who had not had previous surgery, and in 69.4% of those who had. The respective outcome rates for the 2nd posttreatment year were 78 and 63.5%, respectively. The most common complication was the development of persistent paresthesia, which occurred in 15.8% of patients with no previous surgery and 16.3% of those with previous surgery.

Conclusions

Stereotactic radiosurgery with the GK is a safe and effective treatment option for patients with medically refractory idiopathic TN.
Optic radiation tractography integrated into simulated treatment planning for Gamma Knife surgery
Authors: Maruyama Keisuke , Kamada Kyousuke , Shin Masahiro , Itoh Daisuke , Masutani Yoshitaka , Ino Kenji , Tago Masao , Saito Nobuhito
Published: December 2007

Object

No definitive method of preventing visual field deficits after stereotactic radiosurgery for lesions near the optic radiation (OR) has been available so far. The authors report the results of integrating OR tractography based on diffusion tensor (DT) magnetic resonance imaging into simulated treatment planning for Gamma Knife surgery (GKS).

Methods

Data from imaging studies performed in 10 patients who underwent GKS for treatment of arteriovenous malformations (AVMs) located adjacent to the OR were used for the simulated treatment planning. Diffusion tensor images performed without the patient's head being secured by a stereotactic frame were used for DT tractography, and the OR was visualized by means of software developed by the authors. Data from stereotactic 3D imaging studies performed after frame fixation were coregistered with the data from DT tractography. The combined images were transferred to a GKS treatment-planning workstation. Delivered doses and distances between the treated lesions and the OR were analyzed and correlated with posttreatment neurological changes.

Results

In patients presenting with migraine with visual aura or occipital lobe epilepsy, the OR was located within 11 mm from AVMs. In a patient who developed new quadrantanopia after GKS, the OR had received 32 Gy. A maximum dose to the OR of less than 12 Gy did not cause new visual field deficits. A maximum dose to the OR of 8 Gy or more was significantly related to neurological change (p < 0.05), including visual field deficits and development or improvement of migraine.

Conclusions

Integration of OR tractography into GKS represents a promising tool for preventing GKS-induced visual disturbances and headaches. Single-session irradiation at a dose of 8 Gy or more was associated with neurological change.
Radiosurgery for chordomas and chondrosarcomas of the skull base
Authors: Martin Juan J. , Niranjan Ajay , Kondziolka Douglas , Flickinger John C. , Lozanne Karl A. , Lunsford L. Dade
Published: December 2007

Object

Chordomas and chondrosarcomas of the skull base are aggressive and locally destructive tumors with a high tendency for local progression despite treatment. The authors evaluated the effect of stereotactic radiosurgery (SRS) on local tumor control and survival.

Methods

Twenty-eight patients with histologically confirmed chordomas (18) or chondrosarcomas (10) underwent Gamma Knife SRS either as primary or adjuvant treatment. Their ages ranged from 17 to 72 years (median 44 years). The most common presenting symptom was diplopia (26 patients, 93%). In two patients, SRS was the sole treatment. Twenty-six patients underwent between one and five additional surgical procedures. Two underwent an initial trans-sphenoidal biopsy. The average tumor volume was 9.8 cm3. The median dose to the tumor margin was 16 Gy.

Results

No patient was lost to follow-up. Transient symptomatic adverse radiation effects developed in only one patient. The actuarial local tumor control for chondrosarcomas at 5 years was 80 ± 10.1%. For chordomas both the actuarial tumor control and survival was 62.9 ± 10.4%.

Conclusions

Stereotactic radiosurgery is an important option for skull base chordomas and chondrosarcomas either as primary or adjunctive treatment. Multimodal management appears crucial to improve tumor control in most patients.
Peripheral nerve lesions associated with missile-induced pseudoaneurysms
Authors: Roganović Zoran , Mišović Sidor , Kronja Goran , Savić Milenko
Published: December 2007

Object

Reports of traumatic pseudoaneurysms associated with nerve compression are rare, and typically do not focus on the damaged nerves. This prospective study examines the clinical presentation, management, and treatment outcome of such nerve injuries.

Methods

Between 1991 and 1995, 22 patients with a missile-induced nerve injury associated with a pseudoaneurysm were treated surgically at the Belgrade Military Medical Academy. The artery and nerves involved with the injury were treated using appropriate surgical procedures, and both the sensorimotor deficit and pain intensity were assessed.

Results

The occurrence of a pulsatile mass depended on the location of the pseudoaneurysm (p = 0.003) and correlated significantly with the preoperative diagnosis (p < 0.001). In cases in which neurological worsening was due exclusively to the compressive effect of the pseudoaneurysm, the nerves involved were found to be in anatomical continuity intraoperatively, and recovery depended on the actual nerve damage and surgical procedure required (neurolysis or nerve grafting). A symptomatic nerve compression duration of more than 3.5 days was the critical factor that determined if neurapraxia developed into severe nerve damage (p = 0.014). Pain syndromes responded well and rapidly to the surgical treatment (p < 0.001).

Conclusions

Whether or not a missile-induced pseudoaneurysm associated with a nerve lesion will be recognized before surgery depends on its location and clinical presentation. The nerves involved almost invariably exhibit a lesion in continuity, but the resulting nerve damage can be severe, particularly if surgery is delayed for more than 3 to 4 days after neurological worsening has begun. A successful outcome may be expected if an appropriate surgical technique (neurolysis or grafting) is chosen on the basis of the intraoperative discovery of nerve action potentials.
Deep brain stimulation for treatment of obesity in rats
Authors: Sani Sepehr , Jobe Kirk , Smith Adam , Kordower Jeffrey H. , Bakay Roy A. E.
Published: December 2007

Object

Given the success of deep brain stimulation (DBS) in a variety of applications (for example, Parkinson disease and essential tremor), other indications for which there is currently little effective therapy are being evaluated for clinical use of DBS. Obesity may be one such indication. Studies of the control of feeding and appetite by neurosurgical lesioning have been completed previously. This study was conducted to test the authors' hypothesis that continuous bilateral stimulatory inhibition of the rat lateral hypothalamic nucleus (LH) would lead to significant and sustained decrease in food intake and subsequent weight loss.

Methods

Sixteen Sprague–Dawley rats were maintained on a high-fat diet. Daily food intake and weight gain were measured for 7 days, at which time the animals underwent stereotactic placement of 0.25-mm-diameter bipolar stimulating electrodes bilaterally in the LH. On postoperative Day 7, eight animals began to receive continuous stimulation of the LH. The remaining eight animals were left unstimulated as the control group. Individual animal weight, food intake, and water intake were monitored daily and continuously throughout the experiment until postoperative Day 24.

Results

There was a decreased rate of weight gain after surgery in all animals, but the unstimulated group recovered and resumed a linear weight gain curve. The stimulated group, however, failed to show weight gain and remained below the mean baseline for body mass. There was a significant weight loss between the stimulated and unstimulated groups. On postoperative Day 24, compared with the day of surgery (Day 0), the unstimulated group had a mean weight gain of 13.8%, whereas the stimulated group had a 2.3% weight loss on average (p = 0.001), yielding a 16.1% weight difference between the two groups.

Conclusions

Bilateral electrical stimulatory inhibition of the LH is effective in causing significant and sustained weight loss in rats.
Connectivity of the human pedunculopontine nucleus region and diffusion tensor imaging in surgical targeting
Authors: Muthusamy Kalai A. , Aravamuthan Bhooma R. , Kringelbach Morten L. , Jenkinson Ned , Voets Natalie L. , Johansen-Berg Heidi , Stein John F. , Aziz Tipu Z.
Published: December 2007

Object

The pedunculopontine nucleus (PPN) region of the brainstem has become a new stimulation target for the treatment of gait freezing, akinesia, and postural instability in advanced Parkinson disease (PD). Because PD locomotor symptoms are probably caused by excessive γ-aminobutyric acidergic inhibition of the PPN, low-frequency stimulation of the PPN may overcome this inhibition and improve the symptoms. However, the anatomical connections of this region in humans are not known in any detail.

Methods

Diffusion weighted magnetic resonance (MR) images were acquired at 1.5 teslas, and probabilistic tractography was used to trace the connections of the PPN region in eight healthy volunteers. A single seed voxel (2 × 2 × 2 mm) was chosen in the PPN just lateral to the decussation of the superior cerebellar peduncle, and the Diffusion Toolbox of the Oxford Centre for Functional Magnetic Resonance Imaging of the Brain was used to process the acquired MR images. The connections of each volunteer's PPN region were analyzed using a human brain MR imaging atlas.

Results

The PPN region was connected with the cerebellum and spinal cord below and to the thalamus, pallidum, subthalamic nucleus, and motor cortex above. The regions of the primary motor cortex that control the trunk and upper and lower extremities had the highest connectivity compared with other parts of motor cortex.

Conclusions

These findings suggest that connections of the PPN region with the primary motor cortex, basal ganglia, thalamus, cerebellum, and spinal cord may play important roles in the regulation of movement by the PPN region. Diffusion tensor imaging tractography of the PPN region may be used preoperatively to optimize placement of stimulation electrodes and postoperatively it may also be useful to reassess electrode positions.
Cerebral blood flow measurements and electroencephalograms during carotid endarterectomy.
Authors: Sundt Thoralf M. , Sharbrough Frank W. , Anderson Robert E. , Michenfelder John D.
Published: December 2007

✓ Ninety-three endarterectomies for carotid stenosis were monitored with cerebral blood flow (CBF) measurements, and 113 with both CBF measurements and a continuous electroencephalogram (EEG). Significant CBF increase occurred only when carotid endarterectomy was for a stenosis greater than 90%. A high correlation between CBF and EEG indicated when a shunt was required. To sustain a normal EEG, the CBF ascertained by the initial slope technique must be 18 ml/100 gm/min at an arterial carbon dioxide tension (PaCO2) of 40 torr. The degree of EEG change below this level during occlusion reflected the severity of reduced blood flow and was reversible with replacement of a shunt. The value and limitations of these monitoring techniques and a concept of ischemic tolerance and critical CBF are discussed.
Effect of treatment plan quality on outcomes after radiosurgery for vestibular schwannoma
Authors: Beegle Richard D. , Friedman William A. , Bova Frank J.
Published: December 2007

Object

The goal in this study was to review the effects of treatment plan quality on outcomes after radiosurgery for vestibular schwannoma (VS).

Methods

Between July 1988 and August 2005, 390 patients were treated. The results of this experience have been published recently. In this study the authors looked at dosimetry variables: conformity of treatment plan and steepness of dose gradient, in the same group of patients. Over the duration of this study, dosimetry evolved from a single isocenter with marginal conformity to multiple isocenters with high conformity. Multivariate statistics were used to determine the effects of these variables on tumor control and on two types of complication, facial weakness and facial numbness.

Results

The 5-year actuarial tumor control was 91%. Dosimetry had no effect on tumor control. Eighteen patients (4.6%) reported new-onset facial weakness and 14 (3.6%) reported new-onset facial numbness. Since 1994, when peripheral treatment doses were lowered to 1250 cGy, only three (1%) of 298 patients have experienced facial weakness and two (0.7%) of 298 have experienced facial numbness. Statistical analysis confirms, as in the prior study, that treatment volume and treatment dose are significant predictors of both facial weakness and facial numbness. In this model, prior tumor growth was also significant. Dosimetry, however, is definitely not a significant predictor of either complication.

Conclusions

Treatment dose appears to be much more important than treatment plan quality in the prevention of facial numbness or weakness after radiosurgery for VS.
Significance of the tentorial alignment in approaching the trigeminal nerve and the ventral petrous region through the suboccipital retrosigmoid technique
Authors: Sade Burak , Lee Joung H.
Published: December 2007

Object

In this study, the authors aimed to identify the factors that would predict the operative distance between the trigeminal nerve (fifth cranial nerve) and the acousticofacial nerve complex (seventh–eighth cranial nerves) preoperatively when approaching the cerebellopontine angle (CPA) through the suboccipital retrosigmoid approach.

Methods

In 40 consecutive patients who underwent microvascular decompression of the trigeminal nerve via a sub-occipital retrosigmoid approach for trigeminal neuralgia, the following three parameters were assessed on preoperative magnetic resonance images: 1) the angle between the tentorium and the line drawn from the hard palate (tentorial angle); 2) the angle between the lines drawn along the petrous bones ventral to the internal auditory canals (petrous angle); and 3) the angle between the tentorium and the line connecting the opisthion to the inion (occipital angle). The distance between the trigeminal nerve and the acousticofacial nerve complex (referred to as “distance”) was measured intraoperatively. Statistical analysis was performed using the Pearson correlation test.

Results

The mean values were 50.9 ± 11.5° for the tentorial angle, 102.5 ± 13.1° for the petrous angle, 83.4 ± 9.7° for the occipital angle, and 3.1 ± 1.5 mm for distance. There was a strong inverse correlation between the tentorial angle and distance (r = −0.228, p = 0.08). The mean distance was 3.5 ± 1.9 mm for a tentorial angle less than 51° and 2.7 ± 1.1 mm for a tentorial angle of at least 51°. No correlation existed between either the petrous or occipital angles and distance.

Conclusions

The distance between the trigeminal nerve and acousticofacial nerve complex decreases in the presence of a steep tentorial angle. This limits the operating field between these cranial nerves when reaching the petroclival or the superior CPA regions through the retrosigmoid approach. Awareness of such anatomical features at the time of pre-operative planning is of paramount importance in selecting the optimum surgical approach and minimizing operative complications.
Long-term follow-up of meningiomas of the cavernous sinus after surgical treatment alone
Authors: Sindou Marc , Wydh Ernesto , Jouanneau Emmanuel , Nebbal Mustapha , Lieutaud Thomas
Published: December 2007

Object

The authors report on the long-term outcome in 100 consecutive patients with meningiomas arising from the cavernous sinus (CS) with compressive extension outside the CS. The treatment in all cases was surgery alone without adjuvant radiosurgery or radiotherapy. The aim of this study was to evaluate the percentage of patients in whom surgery alone was able to produce long-term tumor control.

Methods

All 100 patients harbored meningiomas with supra- and/or laterocavernous extension, and 27 had petro-clival extension. Surgery was performed via frontopterionotemporal craniotomy associated with orbital and/or zygomatic osteotomy in 97 patients. Proximal control of the internal carotid artery at the foramen lacerum was undertaken in 65 patients; the paraclinoid carotid segment was exposed extradurally at the space made by the anterior clinoidectomy in 81 patients. For the petroclival tumor extension, a second-stage surgery was performed via a presigmoid–retro-labyrinthine or retrosigmoid approach in 13 and 14 patients, respectively.

Results

The mortality rate was 5% and two patients had severe hemiplegic or aphasic sequelae. The creation or aggravation of disorders in vision, ocular motility, or trigeminal function occurred in 19, 29, and 24% of patients respectively, with a significantly higher rate of complications when resection was performed inside the CS (p < 0.05).

Gross-total removal of both the extra- and intracavernous portions was achieved in 12 patients (Group 1), removal of the extracavernous portions with only a partial resection of the intracavernous portion in 28 patients (Group 2), and removal only of the extracavernous portions was performed in 60 patients (Group 3). The follow-up period ranged from 3 to 20 years (mean 8.3 years). There was no tumor recurrence in Group 1. In the 83 surviving patients in Groups 2 and 3 combined, the tumor remnant did not regrow in 72 patients (86.7%); regrowth was noted in 11 (13.3%).

Conclusions

The results suggest that there is no significant oncological benefit in performing surgery within the CS. Because entering the CS entails a significantly higher risk of complications, radiosurgical treatment should be reserved for remnants with secondary growth and clinical manifestations.
Motor evoked potential mapping and monitoring by direct brainstem stimulation
Authors: Tanaka Satoshi , Takanashi Junko , Fujii Kiyotaka , Ujiie Hiroshi , Hori Tomokatsu
Published: December 2007

✓Motor evoked potentials (MEPs) by direct brainstem stimulation were generated during 12 neurosurgical operations performed in five posterior fossa tumors, six vertebrobasilar aneurysms, and an arachnoid cyst. The anterior aspect of the brainstem was exposed using a subtemporal approach (in six cases), a presigmoid approach (one case), or a lateral suboccipital approach (five cases). A train of five monopolar 5 to 25 mA pulses was then applied, and MEPs were recorded from the extremities. Motor evoked potentials were recorded in all patients (four mappings and seven monitorings) except in a 12-year-old child who underwent surgery for a posterior cerebral artery aneurysm. Although he experienced postoperative motor palsy, the aneurysm ruptured before electrodes could be placed. Two patients with postoperative motor palsy, one with a clival meningioma and one with a basilar trunk aneurysm, had shown significant decreases in MEP amplitude and even complete disappearance of MEPs during intraoperative brainstem stimulation. Motor evoked potentials elicited by direct brainstem stimulation seem to be an accurate neurophysiological monitoring method during operations around the anterior and lateral aspects of the brainstem.
Persistent perioperative hyperglycemia as an independent predictor of poor outcome after aneurysmal subarachnoid hemorrhage
Authors: McGirt Matthew J. , Woodworth Graeme F. , Ali Mohammed , Than Khoi D. , Tamargo Rafael J. , Clatterbuck Richard E.
Published: December 2007

Object

The authors of previous studies have shown that admission hyperglycemia or perioperative hyperglycemic events may predispose a patient to poor outcome after aneurysmal subarachnoid hemorrhage (SAH). The results of experimental evidence have suggested that hyperglycemia may exacerbate ischemic central nervous system injury. It remains to be clarified whether a single hyperglycemic event or persistent hyperglycemia is predictive of poor outcome after aneurysmal SAH.

Methods

Ninety-seven patients undergoing treatment for aneurysmal SAH were observed, and all perioperative variables were entered into a database of prospectively recorded data. Daily serum glucose values were retrospectively added. Patients were examined at hospital discharge (14–21 days after SAH onset), and Glasgow Outcome Scale (GOS) scores were prospectively documented. The GOS score at last follow-up was retrospectively determined. Serum glucose greater than 200 mg/dl for 2 or more consecutive days was defined as persistent hyperglycemia. Outcome was categorized as “poor” (dependent function [GOS Score 1–3]) or “good” (independent function [GOS Score 4 or 5]) at discharge. The independent association of 2-week and final follow-up outcome (GOS score) with the daily serum glucose levels was assessed using a multivariate analysis.

Results

In the univariate analysis, increasing age, increasing Hunt and Hess grade, hypertension, ventriculomegaly on admission computed tomography scan, Caucasian race, and higher mean daily glucose levels were associated with poor (dependent) 2-week outcome after aneurysmal SAH. In the multivariate analysis, older age, the occurrence of symptomatic cerebral vasospasm, increasing admission Hunt and Hess grade, and persistent hyperglycemia were independent predictors of poor (dependent) outcome 2 weeks after aneurysmal SAH. Admission Hunt and Hess grade and persistent hyperglycemia were independent predictors of poor outcome at last follow-up examination a mean 10 ± 3 months after aneurysmal SAH. Isolated hyperglycemic events did not predict poor outcome. Patients with persistent hyperglycemia were 10-fold more likely to have a poor (dependent) 2-week outcome and sevenfold more likely to have a poor outcome a mean 10 months after aneurysmal SAH independent of admission Hunt and Hess grade, occurrence of cerebral vasospasm, or all comorbidities.

Conclusions

Patients with persistent hyperglycemia were seven times more likely to have a poor outcome at a mean of 10 months after aneurysmal SAH. Isolated hyperglycemic events were not predictive of poor outcome. Serum glucose levels in the acute setting of aneurysmal SAH may help predict outcomes months after surgery.
Treatment of blood blister–like aneurysm of the internal carotid artery with stent-assisted coil embolization followed by stent-within-a-stent technique
Authors: Kim Byung Moon , Chung Eun Chul , Park Sung Il , Choi Chun Sik , Won Yu Sam
Published: December 2007

✓Ruptured blood blister–like aneurysms (BBAs) of the internal carotid artery (ICA) are potentially dangerous lesions because of the high risk of intraoperative bleeding associated with their wide fragile neck. The authors discuss cases in which BBAs were treated endovascularly during the chronic stage and report a case in which a ruptured BBA of the ICA was successfully treated in the acute phase with stent-assisted coil embolization and a subsequent stent-within-a-stent procedure.
Neurovascular compression of the abducent nerve causing abducent palsy treated by microvascular decompression
Authors: De Ridder Dirk , Menovsky Tomas
Published: December 2007

✓Isolated abducent palsy is a symptom that can be caused by many different intracranial pathological conditions. In this report the authors describe the case of a patient who suffered isolated abducent palsy resulting from vascular compression of the sixth cranial nerve; surgical treatment consisted of microvascular decompression (MVD).

This 56-year-old man presented with short-lasting episodes of a pulling sensation at the lateral side of his right eye associated with intermittent diplopia, followed by a progressive palsy of the abducent nerve and constant diplopia. Magnetic resonance imaging revealed a neurovascular contact of a dolichoectatic basilar artery with the abducent nerve. The patient underwent surgery consisting of a combined supra- and infratentorial presigmoid approach and subsequent MVD of the abducent nerve. Postoperatively, the abducent nerve palsy resolved within days, and the patient remains free of symptoms with a follow-up time of 4 years.

This is the first report of a neurovascular compression of the abducent nerve treated successfully by MVD.
Nonenhancing tumors of the spinal cord
Authors: White J. Bradley , Miller Gary M. , Layton Kennith F. , Krauss William E.
Published: December 2007

Object

Enhancement of pathological entities in the central nervous system is a common finding when the blood–brain barrier has been compromised. In the brain, the presence or absence of gadolinium enhancement is often an indicator of tumor invasiveness and/or grade. In the spinal cord, however, contrast enhancement has been shown in all tumor types, regardless of grade. In this study the authors explore the incidence of nonenhancing tumors of the spinal cord and the clinical course of patients with these lesions.

Methods

A retrospective analysis was conducted in which investigators examined the patterns of enhancement of histologically proven intramedullary spinal cord tumors that had been evaluated at the Mayo Clinic between 1998 and 2002. The tumors that did not enhance were the subject of this report.

Results

A total of 130 patients with intramedullary tumors were evaluated. Of those, 11 patients (9%) had tumors that did not enhance. Histologically, a majority of tumors were astrocytomas (eight low-grade and two high-grade lesions); one tumor was a subependymoma. Morphologically, most of the tumors were diffuse and none had associated cysts. Tumors spanned from two to seven levels and were located throughout the spinal cord (four cervical, three cervicothoracic, one thoracic, and three thoracolumbar). Biopsy procedures were performed in eight patients, subtotal resection was performed in two, and gross-total resection in one. After a mean follow-up period of 19 months, tumors remained stable in eight patients but progressed in three, two of whom died.

Conclusions

A number of intramedullary spinal cord tumors will not enhance after addition of contrast agents. The absence of enhancement does not imply the absence of tumor.
Intraoperative facet joint injury during anterior cervical discectomy and fusion: an experimental study
Authors: Tsitsopoulos Parmenion Ph. , Tsonidis Christos , Papaioannou Nikolaos , Venizelos Ioannis , Psalla Dimitra , Dessiris Angelos , Tsitsopoulos Philippos
Published: December 2007

Object

Disorders of the cervical spine can be successfully addressed by surgical intervention when the choice of such intervention takes into account the possible complications in the treated and adjacent structures. The aim of this study was to investigate the potential for intraoperative trauma in cervical zygapophysial joints and to describe possible pathological changes that may occur during cervical spine surgery.

Methods

Fifteen sheep underwent surgical intervention via an anterior cervical approach; discectomy at the C5–6 level was performed. In 10 animals, the discectomy was accompanied by titanium cage fusion. The sheep were killed immediately after completion of the operation. Radiological examination of the isolated cervical spines followed. Furthermore, the cervical spines were submitted to decalcification and incised using a microtome, and tissue sections were then studied using light microscopy.

Results

Radiological examination was used to assess vertebral alignment, vertebral body (VB) morphology, implant position, and endplate and facet joint gross morphology. Histological examination of the endplate and VB demonstrated degenerative lesions as well as cellular necrosis. The study of the facet joints at the treated as well as at adjacent segments (both above and below) revealed in some cases edema between the collagen fibers of the joint capsules, congestion, and microhemorrhages. Injuries were evident in animals in which the Caspar device was used.

Conclusions

Histopathologically confirmed lesions occurred in facet joints while anterior cervical spine surgery was being performed in sheep. The findings were indicative of trauma and, in the case of human spine surgery, could possibly account for several postoperative complications and patient complaints.
Basilar invagination: craniocervical instability treated with cervical traction and occipitocervical fixation
Authors: Botelho Ricardo V. , Neto Eliseu B. , Patriota Gustavo C. , Daniel Jefferson W. , Dumont Paulo A. S. , Rotta José M.
Published: December 2007

✓ The upward odontoid displacement observed in basilar invagination (BI) is generally associated with a horizontal clivus and craniocervical kyphosis, conditions that exert ventral compression at the spinomedullary junction. Ventral brainstem decompression by reduction or elimination of the odontoid invagination is part of the desired treatment. The authors describe a case of BI in an adult, who was effectively treated with the easy and safe reduction of odontoid invagination via cervical traction. Normalization of kyphosis at the craniovertebral junction and the vertical position of both a previously horizontal clivus and the cerebellar tentorium demonstrated that these conditions were not part of the original malformation but instead were caused by a reducible craniovertebral instability.
Comparison of cervical spine kinematics using a fluoroscopic model for adjacent segment degeneration
Authors: Cheng Joseph S. , Liu Fei , Komistek Richard D. , Mahfouz Mohamed R. , Sharma Adrija , Glaser Diana
Published: December 2007

Object

In this cervical spine kinematics study the authors evaluate the motions and forces in the normal, degenerative, and fused states to assess how alteration in the cervical motion segment affects adjacent segment degeneration and spondylosis.

Methods

Fluoroscopic images obtained in 30 individuals (10 in each group with disease at C5–6) undergoing flexion/extension motions were collected. Kinematic data were obtained from the fluoroscopic images and analyzed with an inverse dynamic mathematical model of the cervical spine that was developed for this analysis.

Results

During 20° flexion to 15° extension, average relative angles at the adjacent levels of C6–7 and C4–5 in the fused patients were 13.4° and 8.8° versus 3.7° and 4.8° in the healthy individuals. Differences at C3–4 averaged only about 1°. Maximum transverse forces in the fused spines were two times the skull weight at C6–7 and one times the skull weight at C4–5, compared with 0.2 times the skull weight and 0.3 times the skull weight in the healthy individuals. Vertical forces ranged from 1.6 to 2.6 times the skull weight at C6–7 and from 1.2 to 2.5 times the skull weight at C4–5 in the patients who had undergone fusion, and from 1.4 to 3.1 times the skull weight and from 0.9 to 3.3 times the skull weight, respectively, in the volunteers.

Conclusions

Adjacent-segment degeneration may occur in patients with fusion due to increased motions and forces at both adjacent levels when compared with healthy individuals in a comparable flexion and extension range.
In vitro flexibility of the cervical spine after ventral uncoforaminotomy
Authors: Schmieder Kirsten , Kettner Annette , Brenke Christopher , Harders Albrecht , Pechlivanis Ioannis , Wilke Hans-Joachim
Published: December 2007

Object

Degenerative spine disorders are, in the majority of cases, treated with ventral discectomy followed by fusion (also known as anterior cervical discectomy and fusion). Currently, nonfusion strategies are gaining broader acceptance. The introduction of cervical disc prosthetic devices was a natural consequence of this development. Jho proposed anterior uncoforaminotomy as an alternative motion-preserving procedure at the cervical spine. The clinical results in the literature are controversial, with one focus of disagreement being the impact of the procedure on stability. The aim of this study was to address the changes in spinal stability after uncoforaminotomy.

Methods

Six spinal motion segments derived from three fresh-frozen human cervical spine specimens (C2–7) were tested. The donors were two men whose ages at death were 59 and 80 years and one woman whose age was 80 years. Bone mineral density in C-3 ranged from 155 to 175 mg/cm3. The lower part of the segment was rigidly fixed in the spine tester, whereas the upper part was fixed in gimbals with integrated stepper motors. Pure moment loads of ± 2.5 Nm were applied in flexion/extension, axial rotation, and lateral bending. For each specimen a load-deformation curve, the range of motion (ROM), and the neutral zone (NZ) for negative and positive directions of motion were calculated. Median, maximum, and minimum values were calculated for the six segments and normalized to the intact segment. Tests were done on the intact segment, after unilateral uncoforaminotomy, and after bilateral uncoforaminotomy.

Results

In lateral bending a strong increase in ROM and NZ was detectable after unilateral uncoforaminotomy on the right side. Overall, the ROM during flexion/extension was less influenced after uncoforaminotomy. The ROM and NZ during axial rotation to the left increased strongly after right unilateral uncoforaminotomy. Changes after bilateral uncoforaminotomy were marked during axial rotation to both sides.

Conclusions

Following unilateral uncoforaminotomy, a significant alteration in mobility of the segment is found, especially during lateral bending and axial rotation. The resulting increase in mobility is less pronounced during flexion and least evident on extension. Further investigations of the natural course of disc degeneration and the impact on mobility after uncoforaminotomy are needed.
Basilar impression and osteogenesis imperfecta: a 21-year retrospective review of outcomes in 20 patients
Authors: Ibrahim Ahmed G. , Crockard H. Alan
Published: December 2007

Object

Basilar impression (BI) secondary to osteogenesis imperfecta (OI) is a rare but debilitating condition that is often progressive unless it is halted. More recently, ventral decompression surgery has been advocated for this condition. This study is a retrospective review of the 21-year experience of ventral decompression surgery and dorsal occipitocervical fixation in patients with BI secondary to OI and is the largest patient series reported to date.

Methods

Twenty patients treated between 1982 and 2003 by the senior author at the authors' institution were included in this study. All patients underwent ventral decompression surgery followed by dorsal craniocervical stabilization. Patients were followed up for a median of 10 years.

Results

There were no intraoperative or perioperative deaths. Postoperatively, 16 of 20 (80%) patients showed objective improvement or maintained their good preoperative level of function. After surgery, of the 15 patients admitted with Karnofsky Performance Scale (KPS) scores of 70% or less, 11 improved, two remained unchanged, one patient's condition deteriorated, and one patient died of an unrelated cause. Of five patients admitted with a KPS score of 80% or greater, no patient's condition deteriorated in the short- and midterm period, but one patient had recurrence 15 years after surgery. At the end of follow-up, 25% of the patients had recurrence of brainstem compression symptoms or had died, and 15% showed no improvement after surgery. All of the remaining patients (60%) had sustained a long-term benefit from surgery.

Conclusions

Aggressive ventral decompression surgery and dorsal stabilization for patients with BI secondary to OI can not only halt disease progression but can also produce a good and sustainable long-term functional outcome, even in those patients who present as severely symptomatic. Patients who presented early with minor symptoms had good long-term outcomes.
Cancer Therapy Disparity: Unequal Access to Breast Cancer Therapeutics and Drug Funding in Canada
Authors: Verma S. , Sehdev S. , Joy A. A.
Published: December 2007

Adjuvant therapy has made a significant contribution in reducing breast cancer–specific mortality. Standard chemotherapeutics and tamoxifen have been the mainstay treatment for years, but recent clinical evidence supports the use of novel small-molecule therapy and aromatase inhibitor therapy in selected settings, challenging not only the traditional paradigm of breast cancer treatment, but also provincial funding of oncologic care across Canada. The disparity in access to aromatase inhibitor therapy for postmenopausal women with early-stage hormone-sensitive breast cancer across Canada is highlighted as an example.
Minds That Matter: 2007 Gairdner International Awards Lectures
Authors: Krasnoshtein F. , Nikolov N.
Published: December 2007

On October 25 and 26, 2007, at the University of Toronto, the Gairdner Foundation in partnership with Canadian Institutes of Health Research presented a two-day international symposium titled Minds That Matter. The symposium featured academic lectures by Gairdner Award winners past and present and by other leading biomedical scientists. These distinguished researchers share many characteristics in common: creativity, vision, tenacity, and driving curiosity to illuminate discovery with high degree of relevance. The present article summarizes the 2007 Gairdner Award lectures.
Complex rearrangement of chromosomes 7q21.13‐q22.1 confirms the ectrodactyly‐deafness locus and suggests new candidate genes
Authors: Bernardini Laura , Palka Chiara , Ceccarini Caterina , Capalbo Anna , Bottillo Irene , Mingarelli Rita , Novelli Antonio , Dallapiccola Bruno
Published: December 2007

Complex chromosomal rearrangements with more than two breakpoints are rare. We report on a 5‐year‐old girl, evaluated because of psychomotor delay, ectrodactyly of right hand and feet, craniofacial dysmorphic features, cleft palate, deafness, and tetralogy of Fallot. A standard karyotype suggested a small intrachromosomal duplication of chromosome 7q. The chromosomal rearrangement was characterized by mBAND, which disclosed a reciprocal interstitial translocation t(7;8)(q21q22;q23q24). FISH analysis and array‐CGH analysis showed a paracentric inversion of 7q and a microdeletion of 7q21.13. The parents had normal chromosomes. The deletion found in the present patient confirms that candidate region of ectrodactyly‐deafness (OMIM 220600) maps to 7q21 and suggests new candidate genes for that disorder. This patient also had facial features reminiscent of tricho‐rhino‐phalangeal syndrome and one chromosome breakpoint involved band 8q24, a locus for this disorder. In addition, FOG1 gene maps to 8q23 and has been implicated in a subset of subjects with tretralogy of Fallot. We suggest that the aberration of 8q may have contributed to her facial and cardiac findings. © 2007 Wiley‐Liss, Inc.
Priorities for public health research on craniosynostosis: Summary and recommendations from a Centers for Disease Control and Prevention‐sponsored meeting
Authors: Rasmussen Sonja A. , Yazdy Mahsa M. , Frías Jaime L. , Honein Margaret A.
Published: December 2007

On June 8–9, 2006, the National Center on Birth Defects and Developmental Disabilities at the Centers for Disease Control and Prevention held a meeting entitled “Prioritizing a Public Health Research Agenda for Craniosynostosis”. The meeting goals were to review current knowledge in the area, discuss research gaps, and identify future priorities for public health research. Participants with a broad range of expertise (including clinical and molecular genetics, cranial morphology, epidemiology, pediatrics, psychology, public health, and surgery) contributed to the development of the research agenda. Meeting participants were asked to consider public health significance and feasibility when identifying areas of priority for future public health research. Participants identified several priorities, including the need to better delineate the prevalence and phenotype of craniosynostosis (CS); to identify factors important in the causation of CS (including potentially modifiable environmental risk factors as well as genes involved in isolated CS and gene–gene and gene–environment interactions); and to better understand short‐ and long‐term outcomes of CS (e.g., surgical, neurocognitive and neuropsychological outcomes, psychological adjustment, and social relationships) and issues related to clinical care that could affect those outcomes. The need for improved collaboration among clinical treatment centers and standardization of data collection to address these priorities was emphasized. These priorities will be used to guide future public health research on CS. © 2007 Wiley‐Liss, Inc.
Der optimale Molekülsatz für Screening‐Anwendungen: eine Synthesestrategie
Authors: Nielsen Thomas E. , Schreiber Stuart L.
Published: December 2007

Die Entwicklung von niedermolekularen Sonden und Wirkstoffen umfasst mindestens drei Phasen: 1) eine Auffindungsphase, die oft die Synthese und das Screening von Wirkstoffkandidaten erfordert, 2) eine Optimierungsphase, die die Synthese und Analyse von Strukturvarianten erfordert, und 3) eine Produktionsphase, die eine effiziente Synthese der optimierten molekularen Sonde oder des optimierten Wirkstoffs erfordert. Der Einsatz spezialisierter Projektgruppen hat oft zur Folge, dass die einzelnen Stufen ohne vorherige Koordination der Aktivitäten ausgeführt werden; so können z. B. vertraglich gebundene (“outgesourcte”) Chemiker in der ersten Stufe und unternehmensinterne Medizinal‐ und Prozesschemiker in den zweiten bzw. dritten Stufen eingesetzt werden. Eine koordinierte Planung im Vorfeld der ersten Screens findet oft nicht statt, und jede der Projektgruppen kann auf einen Flaschenhals stoßen, den man bei vorheriger Planung im Prinzip hätte vermeiden können. Die Herausforderung besteht deshalb darin, eine neue Art von Chemie zu entwickeln, die eine für ein Screening geeignete Sammlung biologisch aktiver Moleküle hervorbringt, die in allen drei Phasen der Sonden‐ oder Wirkstoffentwicklung eine erhöhte Erfolgswahrscheinlichkeit haben. Bis dahin ist es ein weiter Weg, erste Fortschritte sind aber zu verzeichnen. In diesem Kurzaufsatz fassen wir eine neuartige Strategie zur diversitätsorientierten Synthese niedermolekularer Verbindungen zusammen, die das Potenzial hat, diese Herausforderungen zu meistern.
Studies on the comprehensive performance of graphite and additives filled high density polyethylene composites
Authors: Sun Changzhi , Zhao Wenyuan , Chen Shigang
Published: December 2007

The comprehensive performance of graphite and additives filled high‐density polyethylene (HDPE) composites is studied in this article. Four graphites with different particle diameters are used as conductive fillers in HDPE/graphite. Plasticizer, nucleator, and certain particle diameter graphite are employed to prepare HDPE composite. The behavior of crystallization and the distribution of graphite are also studied by means of SEM. An orthogonal design experiment is taken to optimize the content of the filler. The experimental results indicate that the positive temperature coefficient (PTC) effect is related to the particle diameter of graphite. And the bending strength of HDPE/graphite composite with the plasticizer and nucleator is two times less than that of HDPE‐graphite blends. Meanwhile, the high PTC intensity (the ratio of peak resistivity to room temperature resistivity) is also preserved. An excellent comprehensive performance conductive composite is prepared. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008