bluuebunny/crossref_metadata_2025 huggingface dataset:
Polymethylmethacrylate-augmented screw fixation for stabilization in metastatic spinal tumors
Authors: Jang Jee Soo , Lee Sang Ho , Rhee Chang Hun , Lee Seung Hoon
Published: May 2009

✓ Screw fixation augmented with polymethylmethacrylate (PMMA) or some other biocompatible bone cement has been used in patients with osteoporosis requiring spinal fusion. No clinical studies have been conducted on PMMA-augmented screw fixation for stabilization of the vertebral column in patients with metastatic spinal tumors. The purpose of this study was to determine whether screw fixation augmented with PMMA might be suitable in patients treated for multilevel metastatic spinal tumors.

Ten patients with metastatic spinal tumors involving multiple vertebral levels underwent stabilization procedures in which PMMA was used to augment screw fixation after decompression of the spinal cord.

Within 15 days, partial or complete relief from pain was obtained in all patients postoperatively. Two of four patients in whom neurological deficits caused them to be nonambulatory before surgery were able to ambulate postoperatively. Neither collapse of the injected vertebral bodies nor failure of the screw fixation was observed during the mean follow-up period of 6.7 months.

Screw fixation augmented with PMMA may offer stronger stabilization and facilitate the instrumentation across short segments in the treatment of multilevel metastatic spinal tumors.
Modified classification of spinal cord vascular lesions
Authors: Spetzler Robert F. , Detwiler Paul W. , Riina Howard A. , Porter Randall W.
Published: May 2009

The literature on spinal vascular malformations contains a great deal of confusing terminology. Some of the nomenclature is inconsistent with the lesions described. Based on the experience of the senior author (R.F.S.) in the treatment of more than 130 spinal cord vascular lesions and based on a thorough review of the relevant literature, the authors propose a modified classification system for spinal cord vascular lesions.

Lesions are divided into three primary or broad categories: neoplasms, aneurysms, and arteriovenous lesions. Neoplastic vascular lesions include hemangioblastomas and cavernous malformations, both of which occur sporadically and familially. The second category consists of spinal aneurysms, which are rare. The third category, spinal cord arteriovenous lesions, is divided into arteriovenous fistulas and arteriovenous malformations (AVMs). Arteriovenous fistulas are subdivided into those that are extradural and those that are intradural, with intradural lesions categorized as either dorsal or ventral. Arteriovenous malformations are subdivided into extradural-intradural and intradural malformations. Intradural lesions are further divided into intramedullary, intramedullary-extramedullary, and conus medullaris, a new category of AVM.

This modified classification system for vascular lesions of the spinal cord, based on pathophysiology, neuroimaging features, intraoperative observations, and neuroanatomy, offers several advantages. First, it includes all surgical vascular lesions that affect the spinal cord. Second, it guides treatment by classifying lesions based on location and pathophysiology. Finally, it eliminates the confusion produced by the multitude of unrelated nomenclatural terms found in the literature.
Pathogenesis of myelopathy in patients with ossification of the posterior longitudinal ligament
Authors: Matsunaga Shunji , Kukita Makoto , Hayashi Kyoji , Shinkura Reiko , Koriyama Chihaya , Sakou Takashi , Komiya Setsuro
Published: May 2009

Object. The goal of this study was to clarify the pathogenesis of myelopathy in patients with ossification of the posterior longitudinal ligament (OPLL) based on the relationship between static compression factors and dynamic factors.

Methods. There was a total of 247 patients, including 167 patients who were conservatively followed for a mean of 11 years and 2 months and 80 patients who had myelopathy at initial consultation and underwent surgery. The changes in clinical symptoms associated with OPLL in the cervical spine were examined periodically.

During the natural course of OPLL in the cervical spine, 37 (22%) of 167 patients developed or suffered aggravated spinal symptoms. All of the patients with a space available for the spinal cord (SAC) less than 6 mm suffered myelopathy, whereas the patients with an SAC diameter of 14 mm or greater did not. No correlation was found between the presence or absence of myelopathy in patients whose SAC diameter ranged from 6 mm to less than 14 mm. In patients with myelopathy whose minimal SAC diameter ranged from 6 mm to less than 14 mm, the range of motion of the cervical spine was significantly greater.

Conclusions. These results indicate that pathological compression by the ossified ligament above a certain critical point may be the most significant factor in inducing myelopathy, whereas below that point dynamic factors may be largely involved in inducing myelopathy.
Evaluation of prognostic factors and clinical outcome in elderly patients in whom expansive laminoplasty is performed for cervical myelopathy due to multisegmental spondylotic canal stenosis. A retrospective comparison with younger patients
Authors: Handa Yuji , Kubota Toshihiko , Ishii Hisamasa , Sato Kazufumi , Tsuchida Akira , Arai Yoshikazu
Published: May 2009

Object. It remains unclear whether elderly patients with compressive cervical myelopathy can be expected to experience a promising surgery-related outcome after undergoing expansive laminoplasty. The purposes of this study were to evaluate the efficacy of expansive laminoplasty in elderly patients with cervical myelopathy due to multisegmental spondylotic canal stenosis and to analyze the effect of preoperative prognostic factors on outcome in elderly compared with younger patients.

Methods. The authors reviewed the cases of 22 elderly (> 70 years of age) and 39 younger patients in whom expansive open-door laminoplasty was performed for cervical myelopathy due to multisegmental spondylotic canal stenosis. The pre- and 12-month postoperative clinical symptoms were evaluated using the Japanese Orthopaedic Association (JOA) disability scale. Factors affecting the clinical outcome were statistically analyzed by evaluating the recovery rate calculated from the JOA scale.

There were no significant differences in the mean value of the preoperative factors, especially preoperative duration of symptoms and severity of preoperative disease, between the elderly and younger patient groups. In all patients, age at the time of the operation was shown to exert no significant influence on clinical outcome. The mean recovery rate was 58.8% in the elderly group and 61.8% in the younger group, and there was no significant intergroup difference. Improvement or attenuation in impaired upper- and lower-leg motor function was shown in all patients as was an absence in decline of sensory impairment of the extremities. In the elderly group, both the duration of symptoms and the severity of canal stenosis significantly (p < 0.05) affected the clinical outcome. In the younger group, the severity of preoperative symptoms had a significant (p < 0.05) influence on clinical outcome, whereas duration of the symptoms did not appreciably affect clinical improvement.

Conclusions. Open-door expansive laminoplasty showed a promising effect on clinical outcome in elderly and younger patients with multisegmental cervical canal stenosis. Significant predictive factors for clinical outcome in the elderly patients were the duration of symptoms and the severity of stenosis, which may involve the static factor causing the cervical myelopathy. To improve the elderly patients' disability, surgery must be performed as early as possible before irreversible changes in the spinal cord develop.
Forestier disease associated with a retroodontoid mass causing cervicomedullary compression
Authors: Patel Naresh P. , Wright Neill M. , Choi William W. , McBride Duncan Q. , Johnson J. Patrick
Published: May 2009

Object. Forestier Disease (FD) is a progressive skeletal disorder affecting predominantly older men. It is also known as diffuse idiopathic skeletal hyperostosis (DISH) and is characterized by massive anterior longitudinal ligament calcification that forms a bridge on the anterior border of the thoracic and subaxial cervical spine. To the authors' knowledge, retroodontoid masses associated with FD have not been described.

Methods. Five patients with FD and multilevel subaxial cervical fusion were treated for retroodontoid masses and cervicomedullary junction (CMJ) compression. There were four men and one woman (mean age 73 years, range 54–86 years). All patients suffered progressive neurological symptoms resulting from anterior compression of the CMJ.

Four patients underwent combined transoral resection of the ligamentous mass followed by an occipitocervical fusion procedure. One patient with circumferential CMJ compression underwent a posterior decompression and occipitocervical fusion. Histopathological examination of the mass showed hypertrophic degenerative fibrocartilage. Early postoperative neurological improvement was noted in all patients. The follow-up period ranged from 4 to 19 months. At the end of the follow-up period, four patients experienced neurological improvement. One patient died 3 weeks postsurgery of pulmonary complications.

Conclusions. The osseous elements of the occipitoatlantoaxial complex are not directly affected by FD. The ligamentous structures of the odontoid process, however, are exposed to significantly altered biomechanics resulting from fusion of the subaxial cervical spine associated with FD. Stress-induced compensatory ligamentous hypertrophic changes at the craniovertebral junction cause CMJ compression and subsequent neurological deterioration. This previously undescribed entity should be considered in patients with FD or DISH who present with progressive quadriparesis. Transoral decompression and posterior fusion are often needed in patients with large masses and severe progressive neurological deficits. Selected patients with smaller masses and milder neurological symptoms may be treated with posterior fusion alone.
Extraforaminal lumbar disc herniations: microsurgical anatomy and surgical approach
Authors: Viswanathan Rajaraman , Swamy Narayana K. , Tobler William D. , Greiner Alson L. , Keller Jeffrey T. , Dunsker Stewart B.
Published: May 2009

Object. Familiarity with the microsurgical anatomy of the far-lateral compartment is essential for operating in patients with far-lateral discs. In this report the authors address the microsurgical anatomy studied in 24 extraforaminal lumbar disc spaces in three cadavers.

Methods. Cadaveric dissections confirmed the authors' operative experience in which they found an arterial arcade to be associated with the nerve trunk. The main trunk of the lumbar artery was located lateral to the exiting nerve root in the region of intervertebral foramen. The trunk of the lumbar spinal nerve descending from the level above was 7 mm (± 3 mm [standard deviation]) lateral to the lumbar artery.

Conclusions. Clarification of the microsurgical anatomy of the far-lateral compartment confirmed the authors' clinical impression that the optimum approach to far-lateral discs is via the inferomedial quadrant of the extraforaminal compartment. In this quadrant, exposure of the main nerve root can be facilitated by dividing the posterior primary ramus and a newly described arterial arcade that envelops the nerve trunk. Once this arcade is divided, the nerve can be retracted with relative ease and safety, and the disc can be removed more easily.
Neuronal survival following remote adenovirus gene delivery
Authors: Boulis Nicholas M. , Turner Danielle E. , Imperiale Michael J. , Feldman Eva L.
Published: May 2009

Object. Virus-mediated central nervous system gene delivery is a promising means of treating traumatized tissue or degenerative diseases. In the present study, the authors examined gene expression and neuronal survival in the spinal cord after sciatic nerve administration of an adenovirus vector expressing a LacZ reporter gene.

Methods. The time course of adenovirus gene expression, DNA fragmentation, and neuronal density were quantified in rat lumbar spinal cord by staining for β-galactosidase (β-Gal), terminal deoxynucleotidyl transferase, and cresyl violet after microinjection of either saline or the reporter virus into rat sciatic nerve. The expression of β-Gal following remote vector delivery peaked at 7 days and declined thereafter but was not accompanied by neuronal cell death, as measured by DNA fragmentation. No significant difference in spinal motor neuron density was detected between virus-treated and control rats at any time point examined. Although the spinal cords removed from rats treated with cyclosporine prior to adenovirus injection contained substantially more neurons staining for β-Gal at 7 days (67% of total neurons), the decay in the number of stained neurons was not paralleled by a decline in motor neuron density.

Conclusions. The authors conclude that remote gene expression is suppressed by a noncytolytic process.
Primary C1–2, intradural, extramedullary meningeal sarcoma with glial fibrillary acidic protein—immunoreactive components: a spinal gliosarcoma?
Authors: Barbagallo Giuseppe M. V. , Lanzafame Salvatore , Nicoletti Giovanni F. , Platania Nunzio , Albanese Vincenzo
Published: May 2009

✓ The authors report an exceedingly rare case of a patient harboring a primary, spinal, C1–2, intradural, extramedullary meningeal sarcoma in which there were glial fibrillary acidic protein-immunoreactive components, but, importantly, no physical connection with neural tissue. On initial diagnostic imaging, neuroradiological features suggestive of a spinal meningioma were demonstrated in this 73-year-old man. He underwent a C1–2 laminectomy and removal of the posterior ring of the foramen magnum, and the lesion was excised. Histological and immunohistochemical testing showed a gliosarcoma. The clinical, radiological, and operative data are reviewed, as are the histopathological findings. To the authors' knowledge, this is the first case of a primary spinal intradural extramedullary gliosarcoma reported in the literature.
Spinal chordoma of the terminal filum
Authors: Bayar M. Akif , Erdem Yavuz , Tanyel Omur , Ozturk Koray , Buharali Zeki
Published: May 2009

✓ Chordomas are extradural tumors and usually originate from sacrococcygeal region, vertebral column, and clivus. The authors present a case of spinal intradural chordoma (terminal filum). To the best of their knowledge, this is the first such case in the English-language literature.
Syringomyelia without hindbrain herniation: tight cisterna magna
Authors: Kyoshima Kazuhiko , Kuroyanagi Takayuki , Oya Fusakazu , Kamijo Yukihiro , El-Noamany Hossam , Kobayashi Shigeaki
Published: May 2009

✓ Idiopathic syringomyelia, which is not associated with any definite pathogenic lesions, has been treated mainly by shunting of the syrinx and rarely by craniocervical decompression. The authors report four cases of syringomyelia thought to be idiopathic syringomyelia but treated by craniocervical decompression with favorable results. Syringomyelia was present without hindbrain herniation. In such cases, the subarachnoid space anterior to the brainstem at the level of the foramen magnum is usually open but the cisterna magna is impacted by the tonsils, a condition the authors term “tight cisterna magna.”

All patients underwent foramen magnum decompression and C-1 laminectomy, and the outer layer of the dura was peeled off. Further intradural exploration was performed when outflow of cerebrospinal fluid (CSF) from the fourth ventricle was deemed to be insufficient. Postoperatively, improvement in symptoms and a reduction in syrinx size were demonstrated in three patients, and a reduction in ventricle size was shown in two.

Syringomyelia associated with tight cisterna magna should not be classified as idiopathic syringomyelia; rather, it belongs to the category of organic syringomyelia such as Chiari malformation. A possible pathogenesis of cavitation is obstruction of the CSF outflow from the foramen of Magendie, and the cavity may be a communicating dilation of the central canal. Ventricular dilation may depend on the extent to which CSF drainage is impaired from the foramina of Luschka. These cavities may respond to craniocervical decompression if it results in sufficient CSF outflow from the foramen of Magendie, even in cases with concomitant hydrocephalus.
Thoracoscopic resection of thoracic neurogenic tumors
Authors: Han Patrick P. , Dickman Curtis A.
Published: May 2009

Object. The authors describe the treatment and results of thoracoscopic resection performed in patients with neurogenic tumors.

Methods. Seven patients with large intrathoracic paraspinal neurogenic tumors underwent a thoracoscopic procedure to achieve gross-total resection. All tumors were entirely intrathoracic and treated thoracoscopically except in one patient whose tumor had an intraspinal extension. Gross-total resection was achieved in all cases. Postoperatively, one patient developed Horner syndrome. The only other complication, transient intercostal neuralgia, resolved in all patients. Clinical examination and magnetic resonance imaging follow-up examination in all patients demonstrated no evidence of recurrent disease (mean follow up 12.5 months).

Conclusions. Endoscopic transthoracic approaches can reduce approach-related soft-tissue morbidity and facilitate a patient's recovery by preserving the normal tissues of the chest wall, by avoiding rib retraction and muscle transection, and by reducing postoperative pain.
Increased pedicle screw pullout strength with vertebroplasty augmentation in osteoporotic spines
Authors: Sarzier John S. , Evans Avery J. , Cahill David W.
Published: May 2009

Object. The authors conducted a biomechanical study to evaluate pedicle screw pullout strength in osteoporotic cadaveric spines. Nonaugmented hemivertebrae were compared with pressurized polymethylmethacrylate (PMMA)—augmented hemivertebrae.

Methods. Six formalin-fixed cadaveric thoracolumbar spines at least two standard deviations below the mean bone mineral density (BMD) for age were obtained. Radiographic and BMD studies were correlated to grades I, II, and III osteoporosis according to the Jekei scale. Each of the 21 vertebrae underwent fluoroscopic placement of 6-mm transpedicular screws with each hemivertebra serving as the control for the contralateral PMMA-augmented hemivertebra. Pedicle screws were then evaluated for biomechanical axial pullout resistance.

Augmented hemivertebrae axial pullout forces were increased (p = 0.0005). The mean increase in pullout force was 181% for Grade I, 206% for Grade II, and 213% for Grade III osteoporotic spines. Augmented Grade I osteoporotic spines demonstrated axial pullout forces near those levels reported in the literature for nonosteoporotic specimens. Augmented Grade II osteoporotic specimens demonstrated increases to levels found in nonaugmented vertebrae with low-normal BMD. Augmented Grade III osteoporotic specimens had increases to levels equal to those found in nonaugmented Grade I vertebrae.

Conclusions. Augmentation of osteoporotic vertebrae in PMMA-assisted vertebroplasty can significantly increase pedicle screw pullout forces to levels exceeding the strength of cortical bone. The maximum attainable force appears to be twice the pullout force of the nonaugmented pedicle screw for each osteoporotic grade.
Biomechanical comparison of four anterior atlantoaxial plate systems
Authors: Kandziora Frank , Pflugmacher Robert , Ludwig Katrin , Duda Georg , Mittlmeier Thomas , Haas Norbert P.
Published: May 2009

Object. The optimum fixation method to achieve atlantoaxial fusion after resection of the odontoid process remains a matter of discussion. Anterior atlantoaxial plate fixation has been described by Harms as a fixation procedure to be performed after transoral odontoid resection. In recent biomechanical and clinical studies investigators have shown that this procedure is a good alternative to established posterior atlantoaxial fixation techniques, but they have also indicated the biomechanical disadvantages of the Harms plate design. Therefore, three new anterior atlantoaxial plate designs were developed. The purpose of this study was to compare these three newly designed plate systems biomechanically with that used in Harms anterior atlantoaxial plate fixation.

Methods. Twenty-four human craniocervical cadaveric specimens were tested in flexion, extension, axial rotation, and lateral bending in a nonconstrained testing apparatus by using a nondestructive stiffness method. Three-dimensional displacement of C1–2 was measured with an optical measurement system. Six different groups were examined: 1) control (24 specimens); 2) unstable (after odontoidectomy and dissection of the atlantoaxial ligaments; 24 specimens); 3) Harms (anterior atlantoaxial plate fixation according to Harms; six specimens); 4) subarticular atlantoaxial plate (SAAP; six specimens); 5) transpedicular atlantoaxial plate (TAAP; six specimens); and 6) subarticular atlantoaxial locking plate (SAALP; six specimens). Stiffness, range of motion, and neutral and elastic zones were determined. Compared with the Harms plate, stiffness was significantly higher when methods for placing the SAAP, TAAP, and SAALP devices were used (p < 0.05). Angular displacement of SAALPs was less than that demonstrated in any other group (p < 0.05). Stiffness values in any direction were significantly greater for the SAALP-fixed specimens than for the TAAP, SAAP, Harms, control, or unstable specimens (p < 0.05).

Conclusions. Experimentally, the SAAP, TAAP, and Harms plate achieved less stable fixation than the SAALP. Therefore, if transoral odontoid resection is performed, SAALP-fixed spines will provide significantly improved stability compared with previous fixation devices and methods. This may be a necessary prerequisite for a fast and uneventful osseous fusion even without additional posterior stabilization.
Influence of cage design on interbody fusion in a sheep cervical spine model
Authors: Kandziora Frank , Schollmeier Georg , Scholz Matti , Schaefer Jan , Scholz Alexandra , Schmidmaier Gerhard , Schröder Ralf , Bail Herman , Duda Georg , Mittlmeier Thomas , Haas Norbert P.
Published: May 2009

Object. The purpose of this study was to compare the characteristics of interbody fusion achieved using an autologous tricortical iliac crest bone graft with those of a cylinder- and a box-design cage in a sheep cervical spine model. This study was designed to determine whether there are differences between three interbody fusion procedures in: 1) ability to preserve postoperative distraction; 2) biomechanical stability; and 3) histological characteristics of intervertebral bone matrix formation.

Methods. Twenty-four sheep underwent C3–4 discectomy and fusion in which the following were used: Group 1, autologous tricortical iliac crest bone graft (eight sheep); Group 2, titanium cylinder-design cage filled with autologous iliac crest bone graft (eight sheep); and Group 3, titanium box-design cage filled with autologous iliac crest graft (eight sheep). Radiography was performed pre- and postoperatively and after 1, 2, 4, 8, and 12 weeks. At the same time points, disc space height, intervertebral angle, and lordosis angle were measured. After 12 weeks, the sheep were killed, and fusion sites were evaluated by obtaining functional radiographs in flexion and extension. Quantitative computerized tomography scans were acquired to assess bone mineral density, bone mineral content, and bone callus volume. Biomechanical testing was performed in flexion, extension, axial rotation, and lateral bending. Stiffness, range of motion, neutral zone, and elastic zone were determined. Histomorphological and histomorphometric analyses were performed, and polychrome sequential labeling was used to determine the time frame of new bone formation.

Over a 12-week period significantly higher values for disc space height and intervertebral angle were shown in cage-treated sheep than in those that received bone graft. Functional radiographic assessment revealed significantly lower residual flexion—extension movement in sheep with the cylinder cage-fixed spines than in those that received bone graft group. The cylinder—design cages showed significantly higher values for bone mineral content, bone callus content, and stiffness in axial rotation and lateral bending than the other cages or grafts. Histomorphometric evaluation and polychrome sequential labeling showed a more progressed bone matrix formation in the cylindrical cage group than in both other groups.

Conclusions. Compared with the tricortical bone graft, both cages showed significantly better distractive properties. The cylindrical cage demonstrated a significantly higher biomechanical stiffness and an accelerated interbody fusion compared with the box-design cage and the tricortical bone graft. The differences in bone matrix formation within both cages were the result of the significantly lower stress shielding on the bone graft by the cylinder-design cage.
Percutaneous pedicle screw fixation of the lumbar spine: preliminary clinical results
Authors: Foley Kevin T. , Gupta Sanjay K.
Published: May 2009

Object. Standard techniques for pedicle screw fixation of the lumbar spine involve open exposures and extensive muscle dissection. The purpose of this study was to report the initial clinical experience with a novel device for percutaneous posterior fixation of the lumbar spine.

Methods. An existing multiaxial lumbar pedicle screw system was modified to allow screws to be placed percutaneously by using an extension sleeve that permits remote manipulation of the polyaxial screw heads and remote engagement of the screw-locking mechanism. A unique rod-insertion device was developed that linked to the screw extension sleeves, allowing for a precut and -contoured rod to be placed through a small stab wound. Because the insertion device relies on the geometrical constraint of the rod pathway through the screw heads, minimal manipulation is required to place the rods in a standard submuscular position, there is essentially no muscle dissection, and the need for direct visual feedback is avoided. Twelve patients (six men and six women) who ranged in age from 23 to 68 years underwent pedicle screw fixation in which the rod-insertion device was used. Spondylolisthesis was present in 10 patients and osseous nonunion of a prior interbody fusion was present in two. All patients underwent successful percutaneous fixation. Ten patients underwent single-level fusions (six at L5—S1, three at L4–5, and one at L2–3), and two underwent two-level fusions (one from L3–5 and the other from L4—S1). The follow-up period ranged from 10 to 19 months (mean 13.8 months).

Conclusions. Although percutaneous lumbar pedicle screw placement has been described previously, longitudinal connector (rod or plate) insertion has been more problematic. The device used in this study allows for straightforward placement of lumbar pedicle screws and rods through percutaneous stab wounds. Paraspinous tissue trauma is minimized without compromising the quality of spinal fixation. Preliminary experience involving the use of this device has been promising.
Spine surgery in morbidly obese patients
Authors: Telfeian Albert E. , Reiter G. Timothy , Durham Susan R. , Marcotte Paul
Published: May 2009

Object. The diagnosis, treatment, and postoperative care of morbidly obese patients undergoing spinal surgery require modifications for body habitus. With a growing percentage of the United States population becoming morbidly obese, the surgeon may need elective or emergency treatment plans that address the special needs of these patients. The authors retrospectively reviewed the diagnosis, treatment, and postoperative care of the severely obese patient undergoing spinal surgery.

Methods. To assess the associated results and complications of management that required modification for body habitus, 12 patients were included in the study (nine females); the mean age was 50 years and mean weight was 320 lb. Cases of cervical (two cases), thoracic (four cases), and lumbar surgeries (six cases) were included. The follow-up period ranged from 6 months to 2 years. Patients presented with myelopathy (five cases), radicular pain and weakness (four cases), radiculopathy (two cases), and cauda equina syndrome (one patient). Chronic progressive neurological deterioration secondary to spinal cord compression was demonstrated in nine patients and acute pain and/or weakness secondary to nerve root compression was observed in three patients.

Conclusions. The authors found that although morbidly obese patients may present late in the course of their symptoms and require modifications in the use of standard neuroimaging, operative facilities, and treatment plans, open mindedness and persistence can yield satisfactory results in most cases.
Magnetic resonance imaging correlation in pediatric spinal cord injury without radiographic abnormality
Authors: Dare Amos O. , Dias Mark S. , Li Veetai
Published: May 2009

Object. The authors conducted a study to determine correlations between clinical syndromes and early magnetic resonance (MR) imaging—documented findings in children with spinal cord injury without radiographic abnormality (SCIWORA).

Methods. The authors retrospectively reviewed the records obtained in 20 patients who presented with SCIWORA to the Children's Hospital of Buffalo between 1992 and 1999. Initial neurological syndromes, subsequent hospital course and outcome, and early MR imaging findings obtained using conventional sequences on a 1.5-tesla unit were recorded. Neurological syndromes on presentation were complete (Frankel Grade A) in two patients (10%), severe partial (Frankel Grade C) in one patient (5%), and mild partial (Frankel Grade D) in 17 patients (85%). Partial neurological deficits resolved in 14 (78%) of 18 patients within 72 hours and lasted more than 72 hours in four patients (22%). Magnetic resonance imaging was performed in both patients presenting with complete injuries and in 17 of 18 patients presenting with partial neurological deficits. The studies were obtained within 24 hours in 17 patients (85%). Neuroimaging revealed spinal cord swelling at the cervical level in one of the children with complete injury and cord edema with associated hemorrhage at cervical and thoracic levels in the other. Neural and extraneural elements were shown to be normal in all 17 patients with partial injuries who underwent MR imaging, including in the four patients with partial motor deficits lasting more than 72 hours.

Conclusions. In this series, the predominant neurological presentation of SCIWORA was a mild, partial syndrome that resolved within 72 hours. Magnetic resonance imaging revealed abnormal features only in those patients with complete neurological deficits. These findings suggest that in the acute setting conventional MR imaging sequences may lack the sensitivity to demonstrate neural and extraneural abnormalities associated with partial or temporary neurological deficits of SCIWORA, even when those deficits persist beyond 72 hours.
Preinjury cervical alignment affecting spinal trauma
Authors: Maiman Dennis J. , Yoganandan Narayan , Pintar Frank A.
Published: May 2009

Object. The authors tested the hypothesis that initial alignment of the head—neck complex affects cervical spine injury mechanism, trauma rating, injury classification based on stability, and fracture pattern.

Methods. Thirty intact human cadaveric head—neck complexes were prepared by fixing the thoracic end in polymethylmethacrylate. The cranium was unconstrained. The initial spinal alignment was described in terms of eccentricity, defined as the anteroposterior position of the occipital condyles with respect to the T-1 vertebral body. The specimens were subjected to impact loading delivered using an electrohydraulic testing device. Outcomes after injury were identified using radiography and computerized tomography. The mechanisms of injury were classified according to fracture pattern into compression—extension, compression—flexion, hyperflexion, and vertical compression. Trauma was graded according to the Abbreviated Injury Scale rating system. Based on clinical assessment, injuries were classified as stable or unstable. Injuries were also classified into bone fracture or nonfracture groups. Analysis of variance tests were used to determine the influence of eccentricity on spinal injury outcomes. Eccentricity significantly influenced the mechanism of injury (p < 0.0001), trauma rating (p < 0.005), and fracture (p < 0.0001) classification. Statistically significant differences, however, were not apparent when the classification of injury was based on stability considerations.

Conclusions. Spinal alignment is a strong determinant of the biomechanics of impact-induced cervical spine injury.
A collagen-based sealant to prevent in vivo reformation of epidural scar adhesions in an adult rat laminectomy model
Authors: Liu Song , Boutrand Jean Pierre , Bittoun Jacques , Tadie Marc
Published: May 2009

Object. The authors investigated the effect of a collagen-based sealant, Gel Amidon Oxydé (GAO), in preventing the reformation of epidural scar adhesions in an adult rat model of laminectomy.

Methods. Thirty-two adult Sprague—Dawley rats underwent a complete L5–6 laminectomy, after which the dura mater was exposed and the left adjacent L-4 and L-5 nerve roots were exposed. The surgical wound was then closed; 1 month later it was reopened. The epidural scar adhesions that developed were observed and carefully removed, leaving clean dura and nerve roots reexposed. In 16 experimental rats, GAO was placed onto the reexposed dura and around the nerve roots before it polymerized. No treatment was performed in 16 control rats. Postoperatively, all rats were healthy and without neurological deficit. The incisions healed within 1 week regardless of the treatment with the GAO. Three months after reoperation, magnetic resonance imaging revealed that important epidural adhesions were present in the control rats but not in the experimental rats. These findings were then confirmed by gross anatomical examination in which a white tissue layer was found over the dura without adhesions in the experimental animals, whereas significant epidural scar adhesions were demonstrated in the controls. Histological evaluation of the laminectomy site also showed that the peridural space in the experimental rats was larger than that in the controls.

Conclusions. The authors found that GAO may be a safe and effective antiscarring adhesion biomaterial in vivo. When placed into the laminectomy site, GAO may prove beneficial in preventing the formation and reformation of epidural scar adhesions in humans.
Oxidative stress and heat shock protein response in human paraspinal muscles during retraction
Authors: Lu Kang , Liang Cheng-Loong , Cho Chung-Lung , Chen Han-Jung , Hsu Huan-Chen , Yiin Shuenn-Jiun , Chern Chi-Liang , Chen Yun-Ching , Lee Tao-Chen
Published: May 2009

Object. The need for wide dissection and forceful retraction of paraspinal muscles often required for posterolateral lumbar fusion and fixation may severely jeopardize the muscles, structurally and functionally. The underlying pathophysiology of muscle damage may involve both mechanical and ischemic mechanisms. On the other hand, the surgery-related stress may trigger certain protective responses within the insulted paraspinal muscles. This study was conducted to assess the relationship between the oxidative stress and the stress response mediated by heat shock protein 70 (HSP70) induction within paraspinal muscles being retracted.

Methods. Multifidus muscle specimens were surgically obtained before, during, and after retraction in patients with lumbar spondylolisthesis undergoing posterolateral lumbar fusion, pedicle fixation, and laminectomy. Muscle samples were analyzed to determine HSP70 and malondialdehyde (MDA) levels. Both HSP70 expression and MDA production within multifidus muscle cells were increased significantly by retraction. Expression of HSP70 then decreased after a peak at 1.5 hours of retraction, whereas MDA levels remained elevated even after release of retractors for reperfusion of the muscles. Analysis of histopathological and immunohistochemical evidence indicated that the decline of HSP70 synthesis within muscle cells after prolonged retraction was the result of severe muscle damage.

Conclusions. Results of this study highlight the deleterious effect of intraoperative retraction on human paraspinal muscles at the cellular and molecular levels. The authors also found that intraoperative maneuvers aimed at reducing the oxidative stress within the paraspinal muscles may help to attenuate surgery-related paraspinal muscle damage.
Distribution of genes for parathyroid hormone (PTH)—related peptide, Indian hedgehog, PTH receptor and patched in the process of experimental spondylosis in mice
Authors: Nakase Takanobu , Ariga Kenta , Meng Wenxiang , Iwasaki Motoki , Tomita Tetsuya , Myoui Akira , Yonenobu Kazuo , Yoshikawa Hideki
Published: May 2009

Object. Little is known about the molecular mechanisms underlying the process of spondylosis. The authors determined the extent of genetic localization of major regulators of chondrogenesis such as Indian hedgehog (Ihh) and parathyroid hormone (PTH)—related peptide (PTHrP) and their receptors during the development of spondylosis in their previously established experimental mouse model.

Methods. Experimental spondylosis was induced in 5-week-old ICR mice. The cervical spines were chronologically harvested, and histological sections were prepared. Messenger (m) RNA for PTHrP, Ihh, PTH receptor (PTHR; a receptor for PTHrP), patched (Ptc; a receptor for Ihh), bone morphogenetic protein (BMP)—6, and collagen type X (COL10; a marker for mature chondrocyte) was localized in the tissue sections by performing in situ hybridization.

In the early stage, mRNA for COL10, Ihh, and BMP-6 was absent; however, mRNA for PTHrP, PTHR, and Ptc was detected in the anterior margin of the cervical discs. In the late stage, evidence of COL10 mRNA began to be detected, and transcripts for Ihh, PTHrP, and BMP-6 were localized in hypertrophic chondrocytes adjacent to the bone-forming area in osteophyte. Messenger RNA for Ptc and PTHR continued to localize at this stage. In control mice, expression of these genes was absent.

Conclusions. The localization of PTHrP, Ihh, BMP-6, and the receptors PTHR and Ptc demonstrated in the present experimental model indicates the possible involvement of molecular signaling by PTHrP (through the PTHR), Ihh (through the Ptc), and BMP-6 in the regulation of chondrocyte maturation leading to endochondral ossification in spondylosis.
Neural function preservation and early mobilization after resection of metastatic sacral tumors and lumbosacropelvic junction reconstruction
Authors: Salehi Sean A. , McCafferty Randall R. , Karahalios Dean , Ondra Stephen L.
Published: May 2009

✓ The management of tumors that metastasize to the sacrum remains controversial. Typically, resection of such tumors and reconstruction of the lumbopelvic junction requires sacrifice of neural elements resulting in neurological dysfunction and prolonged periods of bed rest. This severely affects the quality of life in patients in whom there is frequently a limited life expectancy.

The authors describe three patients who underwent subtotal resection of metastatic sacral tumors. Postoperatively, good outcome was demonstrated in all patients.

The authors present a technique for debulking and reconstruction that provides immediate spinopelvic junction stability and allows for early mobilization. Quality of life is significantly improved compared with that resulting from either medical treatment or traditional surgery.
Local recurrence after S2–3 sacrectomy in sacral chordoma
Authors: Ishii Ken , Chiba Kazuhiro , Watanabe Masahiko , Yabe Hiroo , Fujimura Yoshikazu , Toyama Yoshiaki
Published: May 2009

✓ Excision is the treatment of choice in cases of sacral chordoma. Local recurrences, however, have often been observed even after total en bloc resection. The authors assessed outcomes in four cases of tumor recurrence in patients who underwent total en bloc S2–3 resection for sacral chordomas that were located below S-3. The primary recurrences were located at either side of the lateral portion of the remaining sacrum in all patients. In two patients in whom preoperative magnetic resonance imaging indicated no invasion of the tumor into surrounding soft tissues, recurrence in the resected end of the gluteus maximus or piriformis muscle was also observed. The authors therefore recommend that the S2–3 sacrectomy should be performed over an adequate margin, including a part of sacroiliac joints at the bilateral portions of the sacrum and soft tissues such as the gluteus maximus or piriformis muscle.
Vertebral metastatic chemodectoma: imaging and therapeutic octreotide
Authors: U-King-Im Jean Marie , Carroll Thomas A. , Morris Kevin
Published: May 2009

✓ The authors report on the use of external-beam radiotherapy and octreotide in a 32-year-old woman who presented with spinal cord compression secondary to metastatic chemodectoma. Scintigraphy studies were used to confirm the presence of somatostatin receptors. Magnetic resonance imaging, and in particular spinal angiography, were performed to define the extent of spinal metastatic disease. The literature on current investigation and management of vertebral metastatic chemodectoma is reviewed.
Pilocytic astrocytoma of a spinal nerve root
Authors: Philipson Mark Robert , Timothy Jake , Chakrobarthy Aruna , Towns Gerry
Published: May 2009

✓ A case of pilocytic astrocytoma involving a spinal nerve root is reported. A 39-year-old woman presented with a 1-year history of progressive pain and numbness, predominantly in the S-1 dermatome. Magnetic resonance (MR) imaging revealed an intradural lesion at the tip of the conus medullaris. The intradural tumor was excised as was the sacrificed nerve root. Histological examination showed a pilocytic astrocytoma in which there were unusual features of calcification and ossification. At 3-year follow-up review MR imaging demonstrated no residual tumor.

To the best of the authors' knowledge, this is the first case of a primary pilocytic astrocytoma, a tumor typically of central nervous system origin, arising from a spinal nerve root.
Circumferential fracture of the skull base causing craniocervical dislocation
Authors: Rao Ganesh , Arthur Adam S. , Apfelbaum Ronald I.
Published: May 2009

✓ Fractures of the craniocervical junction are common in victims of high-speed motor vehicle accidents; indeed, injury to this area is often fatal. The authors present the unusual case of a young woman who sustained a circumferential fracture of the craniocervical junction. Despite significant trauma to this area, she suffered remarkably minor neurological impairment and made an excellent recovery. Her injuries, treatment, and outcome, as well as a review of the literature with regard to injuries at the craniocervical junction, are discussed.
Use of an aiming device in posterior atlantoaxial transarticular screw fixation
Authors: Neo Masashi , Matsushita Mutsumi , Yasuda Tadashi , Sakamoto Takeshi , Nakamura Takashi
Published: May 2009

✓ Posterior atlantoaxial transarticular screw fixation is an excellent procedure associated with high fusion rates. There is, however, the potential risk of vertebral artery (VA) injury. The authors designed a special aiming device that allows a cannulated screw to be inserted accurately in the most posterior part of the C1–2 joint via the most posterior and medial part of the isthmus of C-2; this screw pathway most safely avoids VA injury. The instruments include an aiming device and a flexible screw-inserting system. The tip of the aiming device is placed on the ridge of the C-2 isthmus just posterior to the atlantoaxial joint. The guide wire should then pass 1 mm below the device tip. The system consists of flexible guide wires, a drill, a tap, and a screwdriver, and the screw is inserted easily via a posterior approach in which the patient's back is not obstructive. Ten patients with atlantoaxial subluxation or osteoarthritis underwent surgery in which the device was used. In all cases, the screws were inserted safely without causing VA injury, although preoperative computerized tomography (CT) reconstructions revealed a high-risk high-riding unilateral VA in three patients. Postoperative CT reconstructions demonstrated that all screws but one were inserted as planned, and successfully cleared the vertebral groove.

In conclusion, this newly designed device is practical and useful for the accurate insertion of screws, thus avoiding VA injury during atlantoaxial transarticular screw fixation.
Inverted-hook occipital clamp system in occipitocervical fixation
Authors: Faure Alexis , Monteiro Ruy , Hamel Olivier , Raoul Sylvie , Szapiro Jacek , Alcheikh Marwan , Bord Eric , Robert Roger
Published: May 2009

✓ The authors describe an occipitocervical fixation procedure in which they use inverted occipital hooks inserted through a burr hole drilled in the squamous part of the occipital bone. Fifteen patients with unstable lesions of the occipitocervical junction underwent occipitocervical internal fixation. The mean follow-up period was 21 months (range 2–63 months). No implant failed, and postoperative immobilization was not required. The placement of a posterior occipitocervical graft (for which fusion is uncertain) can be avoided in certain conditions.
First appearance and sense of the term “spinal column” in ancient Egypt
Authors: Lang Johannes K. , Kolenda Herbert
Published: May 2009

✓ In contemporary anatomical nomenclature terms have often been derived from an ancient perspective of the human body. The term “spinal column” was used in ancient Egypt, symbolized by the “djet column.” The authors discuss the first appearance of the term “spinal column,” taking the ancient Egyptian interaction between religion and daily life into consideration, and they describe the different segments of the spinal column known to the ancient Egyptians.

Inspection of medical papyri provides insight into the knowledge held by ancient Egyptian physicians and embalmers. It is assumed that hieroglyphs were used to depict the different vertebral regions of the spinal column (cervical, thoracic, and lumbar). The knowledge was gleaned, in fact, in pursuit of religious goals.

The djet might be an example of how anatomical knowledge can improve understanding of a symbol that was previously thought to have a primarily religious meaning. The authors maintain that modern medical knowledge is useful for making a more precise and anatomically correct interpretation of the presumed sense intended by the ancient Egyptians.