bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of cervical spinal cord stimulation on cerebral blood flow in the rat
Authors: Sagher Oren , Huang Dah-Luen
Published: May 2009

Object. Spinal cord stimulation (SCS) is frequently used for the treatment of chronic pain. Although the mechanisms by which SCS alleviates pain are unclear, they are believed to involve changes within the dorsal horn of the spinal cord. Spinal cord stimulation has also been found to cause significant vasodilation in the peripheral vasculature. The mechanisms underlying this effect are thought to involve sympathetic blockade. A rostral vasodilatory effect has also been described, but changes in cerebral blood flow (CBF) have been poorly delineated. Using laser Doppler flowmetry (LDF), the authors examined the effects of cervical SCS on CBF in rats.

Methods. Cervical SCS was found to result in a significant increase in cortical LDF values (83 ± 11% [mean ± standard error of the mean]). The increase in cortical LDF values was not accompanied by a significant increase in systemic blood pressure. Stimulation of the upper cervical spinal cord was more effective in inducing LDF changes than was that of the lower cervical cord. Changes in SDS-induced LDF values were significantly attenuated after spinal cord transection at the cervicomedullary junction and by the administration of the sympathetic blocker hexamethonium.

Conclusions. These results indicate that cervical SCS may induce cerebral vasodilation and that this effect may involve indirect effects on vasomotor centers in the brainstem as well as an alteration in sympathetic tone.
Comparison of the effects of melatonin and methylprednisolone in experimental spinal cord injury
Authors: Kaptanoglu Erkan , Tuncel Mürvet , Palaoglu Selçuk , Konan Ali , Demirpençe Ediz , Kilinç Kamer
Published: May 2009

Object. Melatonin is a very effective antioxidant agent. This study was performed to investigate the effects of melatonin in experimental spinal cord injury (SCI). The authors also compared its effects with those of methylprednisolone, which also protects the spinal cord from secondary injury because of its antioxidant effect on membrane lipids.

Methods. Adult male albino rats were used for the study, and paraplegia was produced using a previously described weight-drop technique. Melatonin and methylprednisolone were given intraperitoneally by bolus injections of 100 mg/kg and 30 mg/kg, respectively, immediately after induction of trauma. The animals were killed, and 1-cm samples of injured spinal cord were obtained at 1, 24, and 48 hours postinjury. Lipid peroxidation was estimated by thiobarbituric acid test. Electron microscopic studies were performed to determine the effects of melatonin on neurons, axons, and subcellular organelles after experimental SCI. A grading system was used for quantitative evaluation.

Following SCI, there was significant increase in lipid peroxidation. In melatonin- and methylprednisolone-treated groups, lipid peroxidation was found to decrease to the baseline (preinjury) levels. There was a significant difference between trauma-alone and treatment groups, but no statistical difference was found between the melatonin- and methylprednisolone-treated groups. Electron microscopic findings showed that SCI produced by the weight-drop technique resulted in profound tissue damage.

Conclusions. Both melatonin and methylprednisolone have been shown to protect neuron, axon, myelin, and intracellular organelles including mitochondrion and nucleus. However, this study provides quantitative evidence that this protection of neurons and subcellular organelles of spinal cord after secondary injury is much more obvious in melatonin-treated rats than those treated with methylprednisolone. In view of these data, melatonin has been shown to be very effective in protecting the injured spinal cord from secondary injury.
Beneficial effects of modest systemic hypothermia on locomotor function and histopathological damage following contusion-induced spinal cord injury in rats
Authors: Yu Chen Guang , Jimenez Omar , Marcillo Alexander E. , Weider Brian , Bangerter Kurt , Dietrich W. Dalton , Castro Santiago , Yezierski Robert P.
Published: May 2009

Object. Local spinal cord cooling (LSCC) is associated with beneficial effects when applied following ischemic or traumatic spinal cord injury (SCI). However, the clinical application of LSCC is associated with many technical difficulties such as the requirement of special cooling devices, emergency surgery, and complicated postoperative management. If hypothermia is to be considered for future application in the treatment of SCI, alternative approaches must be developed. The objectives of the present study were to evaluate 1) the relationship between systemic and epidural temperature after SCI; 2) the effects of modest systemic hypothermia on histopathological damage at 7 and 44 days post-SCI; and 3) the effects of modest systemic hypothermia on locomotor outcome at 44 days post-SCI.

Methods. A spinal cord contusion (12.5 mm at T-10) was produced in adult rats that had been randomly divided into two groups. Group 1 rats (seven in Experiment 1; 12 in Experiment 2) received hypothermic treatment (epidural temperature 32–33°C) 30 minutes postinjury for 4 hours; Group 2 rats (nine in Experiment 1; eight in Experiment 2) received normothermic treatment (epidural temperature 37°C) 30 minutes postinjury for 4 hours. Blood pressure, blood gas levels, and temperatures (epidural and rectal) were monitored throughout the 4-hour treatment period. Twice weekly assessment of locomotor function was performed over a 6-week survival period by using the Basso-Beattie-Bresnahan locomotor rating scale. Seven (Experiment 1) and 44 (Experiment 2) days after injury, animals were killed, perfused, and their spinal cords were serially sectioned. The area of tissue damage was quantitatively analyzed from 16 longitudinal sections selected from the central core of the spinal cord.

Conclusions. The results showed that 1) modest changes in the epidural temperature of the spinal cord can be produced using systemic hypothermia; 2) modest systemic hypothermia (32–33°C) significantly protects against locomotor deficits following traumatic SCI; and 3) modest systemic hypothermia (32–33°C) reduces the area of tissue damage at both 7 and 44 days postinjury. Although additional research is needed to study the therapeutic window and long-term benefits of systemic hypothermia, these data support the possible use of modest systemic hypothermia in the treatment of acute SCI.
A biomechanical comparison of the Rogers interspinous and the Lovely—Carl tension band wiring techniques for fixation of the cervical spine
Authors: Brasil Albert V. B. , Coelho Danilo G. , Filho Tarcísio Eloy P. B. , Braga Fernando M.
Published: May 2009

Object. The authors conducted a biomechanical study in which they compared the uses of the Rogers interspinous and the Lovely-Carl tension band wiring techniques for internal fixation of the cervical spine.

Method. An extensive biomechanical evaluation (stiffness in positive and negative rotations around the x, y, and z axes; range of motion in flexion—extension, bilateral axial rotation, and bilateral bending; and neutral zone in flexion—extension, bilateral axial rotation, and lateral bending to the right and to the left) was performed in two groups of intact calf cervical spines. After these initial tests, all specimens were subjected to a distractive flexion Stage 3 ligamentous lesion. Group 1 specimens then underwent surgical fixation by the Rogers technique, and Group 2 specimens underwent surgery by using the Lovely—Carl technique. After fixation, specimens were again submitted to the same biomechanical evaluation. The percentage increase or decrease between the pre- and postoperative parameters was calculated. These values were considered quantitative indicators of the efficacy of the techniques, and the efficacy of the two techniques was compared.

Conclusions. Analysis of the findings demonstrated that in the spines treated with the Lovely—Carl technique less restriction of movement was produced without affecting stiffness, compared with those treated with the Rogers technique, thus making the Lovely—Carl technique clinically less useful.
Validation and use of a finite element model of C-2 for determination of stress and fracture patterns of anterior odontoid loads
Authors: Graham R. Scott , Oberlander Eric K. , Stewart John E. , Griffiths David J.
Published: May 2009

Object. The finite element (FE) method is a powerful tool for the analysis of stress patterns of anatomical structures. In this study a highly refined FE model of C-2 was created and validated. The model was then used to characterize stress patterns, predicted fracture patterns, and transitions between Type II and Type III odontoid fractures.

Methods. An anatomically accurate three-dimensional model of C-2 was created from computerized tomography data obtained from the Visible Human Project. The C-2 model was broken down into an FE mesh consisting of 32,815 elements and 40,969 nodes. For validation, the FE model was constrained and loaded to simulate that used in previous biomechanical studies. The validated model was then loaded in an iterative fashion, varying the orientation of the load within the validated range. A matrix of stress plots was created for comparative analysis.

Results of the validation testing closely correlated with those obtained in previous biomechanical testing. Pure extension loading produced a Type III stress pattern with maximum stress of 134 MPa. Loading at 45° produced a Type II stress distribution with a maximum stress of 123 MPa. These stresses are within 3% and 11%, respectively, of the reported yield stress of cortical bone (138 MPa). In the second portion of the study, systematic variation in the orientation of the load vector revealed that higher stresses were associated with increased lateral angulation and increasing upward inclination of the load vectors. A transition from a Type III to Type II pattern occurred with lateral orientations greater than 15° and with compressive loads of 45°.

Conclusions. The validated C-2 FE model described in this study both qualitatively and quantitatively was able to simulate the behavior of the C-2 vertebra in biomechanical testing. In this study the authors demonstrate the utility of the FE method when used in conjunction with traditional biomechanical testing.
Congenital arthrogryposis associated with atlantoaxial subluxation and dysraphic abnormalities
Authors: Luedemann Wolf O. , Tatagiba Marcos S. , Hussein Sami , Samii Madjid
Published: May 2009

✓ The authors report the case of a 27-year-old woman with an arthrogryposis multiplex congenita (AMC) associated with atlantoaxial subluxation. To the authors' knowledge, this is the first report of its kind. The authors review the literature with reference to dysraphic abnormalities associated with atlantoaxial subluxation and with AMC. The patient presented with severe tetraparesis following a minor traffic accident. She underwent a procedure in which transoral decompression and dorsal stabilization were performed and, postoperatively, made a good clinical outcome. The authors stress the need for diagnostic neuroimaging of the craniocervical junction in patients with AMC.
A viable residual spinal hydatid cyst cured with albendazole
Authors: Baykaner M. Kemali , Doğulu Fikret , Öztürk Gülyüz , Edali Naci , Tali Turgut
Published: May 2009

✓ Spinal hydatid disease is a rare entity that frequently yields to severe, acute-onset neurological deficits. Although the gold standard treatment is total surgical removal of the cysts without inducing any spillage, it may not be possible to perform this in patients with multiple and fragile cysts. In such cases, the neural structures should be adequately decompressed and albendazole should be administered promptly.

The authors describe the case of a 13-year-old girl who was admitted with a history of back pain and acute-onset lower-extremity weakness. Magnetic resonance imaging scans demonstrated severe spinal cord compression caused by multiple cysts involving T-4 and the mediastinum. The patient underwent surgery, and the cysts were removed, except for one cyst that was hardly exposed. Following histopathological confirmation of spinal hydatid disease, she was treated with albendazole for 1 year. One year postoperatively, the residual cyst had gradually shrunk and had almost disappeared.

Although a single case is not sufficiently promising, we believe that administration of albendazole is efficient to prevent recurrences in cases in which it is not possible to obtain total removal of the cysts without inducing spillage.
Capillary hemangioma of the spinal cord
Authors: Roncaroli Federico , Scheithauer Bernd W. , Krauss William E.
Published: May 2009

✓ The authors describe the clinicopathological features of four cases of capillary hemangioma of the spinal cord. All occurred in adult patients. The presenting symptoms were similar to those of more common intramedullary tumors. Radiologically, they resemble other vascular spinal cord tumors. All patients underwent surgery, and the outcomes varied. Histologically, the lesions resembled capillary hemangioma of skin or of soft tissue that is composed of lobules of small capillaries with associated feeding vessels, all enveloped by a delicate fibrous capsule. Capillary hemangiomas of the central and peripheral nervous system are extremely rare. Although examples of these lesions have been described as occurring in the dura mater and in peripheral nerve, including spinal nerve roots, none has occurred within the spinal cord. Knowledge of their existence may help practitioners to avoid misdiagnosis of tumor and resultant overtreatment of these benign lesions.
Minimally invasive retroperitoneal approach for lumbar corpectomy and anterior reconstruction
Authors: Mühlbauer Manfred , Pfisterer Wolfgang , Eyb Richard , Knosp Engelbert
Published: May 2009

✓ The anterior decompressive procedure in which spinal fusion is performed is considered an effective treatment for thoracolumbar fractures and tumors. However, it is also known to be associated with considerable surgery-related trauma. The purpose of this study was to show that lumbar corpectomy and anterior reconstruction can be performed via a minimally invasive retroperitoneal approach (MIRA) and therefore the surgical approach—related trauma can be reduced.

The authors studied retrospectively the hospital records and radiological studies obtained in five patients (mean age 67.4 years, range 59–76 years) who underwent lumbar corpectomy and spinal fusion via an MIRA followed by posterior fixation. Four patients presented with osteoporotic compression fractures at L-2 and L-3, and one patient presented with metastatic disease in L-4 from prostate cancer. Neurological deficits due to cauda equina compression were demonstrated in all patients.

The MIRA provided excellent exposure to facilitate complete decompression and anterior reconstruction in all patients, as verified on follow-up radiographic studies. All patients improved clinically. A 1-year follow-up record is available for four patients and a 6-month follow-up record for the fifth patient; continuing clinical improvement has been observed in all. Radiography demonstrated anatomically correct reconstruction in all patients, as well as a solid fusion or a stable compound union in the four patients for whom 1-year follow-up records were available.

The MIRA allows the surgeon to perform anterior lumbar spine surgery via a less invasive approach. The efficacy and safety of this technique and its potential to reduce perioperative morbidity compared with conventional retroperitoneal lumbar spine surgery should be further investigated in a larger series.
Nonsurgically managed patients with degenerative spondylolisthesis: a 10- to 18-year follow-up study
Authors: Matsunaga Shunji , Ijiri Kosei , Hayashi Kyoji
Published: May 2009

Object. Controversy exists concerning the indications for surgery and choice of surgical procedure for patients with degenerative spondylolisthesis. The goals of this study were to determine the clinical course of nonsurgically managed patients with degenerative spondylolisthesis as well as the indications for surgery.

Methods. A total of 145 nonsurgically managed patients with degenerative spondylolisthesis were examined annually for a minimum of 10 years follow-up evaluation. Radiographic changes, changes in clinical symptoms, and functional prognosis were surveyed.

Progressive spondylolisthesis was observed in 49 patients (34%). There was no correlation between changes in clinical symptoms and progression of spondylolisthesis. The intervertebral spaces of the slipped segments were decreased significantly in size during follow-up examination in patients in whom no progression was found. Low-back pain improved following a decrease in the total intervertebral space size. A total of 84 (76%) of 110 patients who had no neurological deficits at initial examination remained without neurological deficit after 10 years of follow up. Twenty-nine (83%) of the 35 patients who had neurological symptoms, such as intermittent claudication or vesicorectal disorder, at initial examination and refused surgery experienced neurological deterioration. The final prognosis for these patients was very poor.

Conclusions. Low-back pain was improved by restabilization. Conservative treatment is useful for patients who have low-back pain with or without pain in the lower extremities. Surgical intervention is indicated for patients with neurological symptoms including intermittent claudication or vesicorectal disorder, provided that a good functional outcome can be achieved.
Incidence and outcome of kyphotic deformity following laminectomy for cervical spondylotic myelopathy
Authors: Kaptain George J. , Simmons Nathan E. , Replogle Robert E. , Pobereskin Louis
Published: May 2009

Object. The authors undertook a study to explore the predisposing risk factors, frequency of occurrence, and clinical implications of kyphosis following laminectomy for cervical spondylotic myelopathy (CSM).

Methods. Preoperative radiological studies were available in 46 patients with CSM who had undergone laminectomy. Records were reviewed to obtain demographic data and operative reports. Preoperative radiographs were assessed to determine spinal alignment. In a follow-up interview the authors established clinical outcome and patient satisfaction. Postoperative cervical alignment and mobility was also determined by assessing lateral neutral, flexion, and extension x-ray films.

Preoperatively, the cervical spine was shown to be kyphotic in four (9%) of 46, straight in 20 (43%) of 46, and lordotic in 22 (48%) of 46 patients. Nine (21%) of 42 patients with either straight or lordotic alignment demonstrated in the preoperative period developed kyphosis after surgery. Kyphosis developed in six (30%) of 20 patients in whom straight spinal alignment was demonstrated preoperatively and in only three (14%) of 22 patients in whom lordosis was found preoperatively. Clinically, 13 (29%) of 45 patients improved and 19 (42%) of 45 remained unchanged after an average 4-year follow-up period; 36 (80%) patients believed that their surgery was successful (one patient, who was mentally retarded, could not respond to the follow-up questionnaire). Spinal alignment was not predictive of outcome; cervical mobility as demonstrated on flexion and extension, however, correlated with improved functional performance (p = 0.005).

Conclusions. Kyphosis may develop in up to 21% of patients who have undergone laminectomy for CSM. Progression of the deformity appears to be more than twice as likely if preoperative radiological studies demonstrate a straight spine. In this study, clinical outcome did not correlate with either pre- or postoperative sagittal alignment.
Single-stage anterior—posterior decompression and stabilization for complex cervical spine disorders
Authors: Schultz Karl D. , McLaughlin Mark R. , Haid Regis W. , Comey Christopher H. , Rodts Gerald E. , Alexander Joseph
Published: May 2009

Object. To evaluate the applicability and safety of single-stage combined anterior—posterior decompression and fusion for complex cervical spine disorders, the authors retrospectively reviewed 72 consecutive procedures of this type performed using a uniform technique at a single center.

Methods. The indications for decompression and stabilization included: postlaminectomy kyphosis (15 patients), trauma (19 patients), spondylosis and congenital stenosis (32 patients), and ossification of the posterior longitudinal ligament (six patients). All patients underwent anterior cervical corpectomies in which allograft fibula and plates were placed, with 89% of patients undergoing two- or three-level procedures (range one–four levels). Lateral mass plating with autograft (morselized iliac crest) fusion was performed in all patients while the same anesthetic agent was still in effect. A hard cervical collar was used postoperatively in all patients (mean 13 weeks). All patients were followed for a minimum of 2 years (mean 29 months).

Fusion was determined to be successful in all 72 patients (100%). Although the short-term morbidity rate reached 32%, the significant long-term morbidity rate was only 5%. At the 2-year follow-up examination, anterior cervical plate dislodgment was seen in one patient, and 16 of the 516 lateral mass screws implanted were observed to have partially backed out. However, there were no cases of nerve root injury, strut graft extrusion, or anterior plate or screw fracture. There were no clinically significant hardware complications and no patient required repeated operation.

Conclusions. The combined single-stage anterior—posterior decompression, reconstruction, and instrumentation procedure represents a viable option in the treatment of a select group of patients with complex cervical spinal disorders. The technique provides immediate rigid stabilization of the cervical spine, prevents anterior plate failure or strut graft extrusion, and eliminates the need for halo immobilization postoperatively. Furthermore, a higher rate of fusion is achieved with this combined approach than with the anterior approach alone.
Anatomical projection of the cervical uncinate process in ventral, ventrolateral, and posterior decompressive surgery
Authors: Uğur Hasan Çağlar , Uz Aysun , Attar Ayhan , Tekdemir İbrahim , Egemen Nihat , Elhan Alaittin
Published: May 2009

Object. The cervical uncinate processes (UPs), their variations, and the relationships between the neurovascular structures and surrounding bone were investigated in this anatomical study. The object of this study was to highlight the important surgery-related considerations associated with ventral, ventrolateral, and posterior decompressive surgery.

Methods. Forty-nine adult C3–7 dry bone samples were used, and 10 measurements were obtained for each vertebra. The anterior measurements involved the cervical uncinate process (UP): height, width, length, distance between its tip and vertebral foramina, interuncinate process distance, sagittal angle with the superior margin of the vertebral body (VB), VB anteroposterior diameter, and VB width. Posterior measurements involved the vertical distance between the superior border of the lamina at the lamina—facet joint and the tip of the UP, as well as the horizontal distance between the medial-most border of the superior facet and the tip of the UP. All symmetrical structures were measured bilaterally. There were no statistically significant differences between right- and left-sided measurements in this series.

The height of the UP increased gradually at each segmental level between C-3 and C-7. The width of the UP did not change with segmental level (5.0 mm at C-3 compared with 5.3 mm at C-7). On average, the length of the UP was relatively constant. The distance from the tip of the UP to vertebral foramina averaged 1 mm at the C2–3 level and 1.5 mm at the C5–6 level. Interuncinate distance and VB width gradually increased and were highly variable, which appeared to be related with osteophyte formation. There was a slight gradual increase from C-3 to lower segments, and it paralleled with the midline anteroposterior diameter of the same VB. The angle between the UP and the superior margin of the VB exhibited great variety. The posterior measurements decreased gradually from C-3 to C-7.

Conclusions. Based on the data obtained in this study, a surgeon is provided with a three-dimensional orientation as well as anatomical knowledge. This knowledge also allows for a more effective neurovascular decompression by minimizing the surgery-related complications.
In vitro biomechanical analysis of three anterior thoracolumbar implants
Authors: Hitchon Patrick W. , Goel Vijay K. , Rogge Thomas N. , Torner James C. , Dooris Andrew P. , Drake John S. , Yang S. J. , Totoribe Koji
Published: May 2009

Object. The goal of this study was to evaluate the comparative efficacy of three commonly used anterior thoracolumbar implants: the anterior thoracolumbar locking plate (ATLP), the smooth-rod Kaneda (SRK), and the Z-plate.

Methods. In vitro testing was performed using the T9—L3 segments of human cadaver spines. An L-1 corpectomy was performed, and stabilization was achieved using one of three anterior devices: the ATLP in nine spines, the SRK in 10, and the Z-plate in 10. Specimens were load tested with 1.5-, 3-, 4.5-, and 6-Nm in flexion and extension, right and left lateral bending, and right and left axial rotation. Angular motion was monitored using two video cameras that tracked light-emitting diodes attached to the vertebral bodies. Testing was performed in the intact state in spines stabilized with one of the three aforementioned devices after the devices had been fatigued to 5000 cycles at ± 3 Nm and after bilateral facetectomy.

There was no difference in the stability of the intact spines with use of the three devices. There were no differences between the SRK- and Z-plate—instrumented spines in any state. In extension testing, the mean angular rotation (± standard deviation) of spines instrumented with the SRK (4.7 ± 3.2°) and Z-plate devices (3.3 ± 2.3°) was more rigid than that observed in the ATLP-stabilized spines (9 ± 4.8°). In flexion testing after induction of fatigue, however, only the SRK (4.2 ± 3.2°) was stiffer than the ATLP (8.9 ± 4.9°). Also, in extension postfatigue, only the SRK (2.4 ± 3.4°) provided more rigid fixation than the ATLP (6.4 ± 2.9°). All three devices were equally unstable after bilateral facetectomy. The SRK and Z-plate anterior thoracolumbar implants were both more rigid than the ATLP, and of the former two the SRK was stiffer.

Conclusions. The authors' results suggest that in cases in which profile and ease of application are not of paramount importance, the SRK has an advantage over the other two tested implants in achieving rigid fixation immediately postoperatively.
Lasting paraplegia caused by loss of lumbar spinal cord interneurons in rats: no direct correlation with motor neuron loss
Authors: Hadi Bassam , Zhang Y. Ping , Burke Darlene A. , Shields Christopher B. , Magnuson David S. K.
Published: May 2009

Object. The aims of this study were to investigate further the role played by lumbar spinal cord interneurons in the generation of locomotor activity and to develop a model of spinal cord injury suitable for testing neuron replacement strategies.

Methods. Adult rats received intraspinal injections of kainic acid (KA). Locomotion was assessed weekly for 4 weeks by using the Basso, Beattie, and Bresnahan (BBB) 21-point locomotor scale, and transcranial magnetic motor evoked potentials (MMEPs) were recorded in gastrocnemius and quadriceps muscles at 1 and 4 weeks. No changes in transcranial MMEP latency were noted following KA injection, indicating that the descending motor pathways responsible for these responses, including the alpha motor neurons, were not compromised. Rats in which KA injections included much of the L-2 segment (10 animals) showed severe locomotor deficits, with a mean BBB score of 4.5 ± 3.6 (± standard deviation). Rats that received lesions rostral to the L-2 segment (four animals) were able to locomote and had a mean BBB score of 14.6 ± 2.6. Three rats that received only one injection bilaterally centered at L-2 (three animals) had a mean BBB score of 3.2 ± 2. Histological examination revealed variable loss of motor neurons limited to the injection site. There was no correlation between motor neuron loss and BBB score.

Conclusions. Interneuron loss centered on the L-2 segment induces lasting paraplegia independent of motor neuron loss and white matter damage, supporting earlier suggestions that circuitry critical to the generator of locomotor activity (the central pattern generator) resides in this area. This injury model may prove ideal for studies of neuron replacement strategies.
New approach to cervical flexion deformity in ankylosing spondylitis
Authors: Duff Sarah E. , Grundy Paul L. , Gill Steven S.
Published: May 2009

✓ The treatment of cervical fixed flexion deformity in ankylosing spondylitis presents a challenging problem that is traditionally managed by a corrective cervicothoracic osteotomy. The authors report a new approach to this problem that involves performing a two-level osteotomy at the level of maximum spinal curvature, thereby achieving complete anatomical correction in a one-stage procedure.

This 48-year-old woman with ankylosing spondylitis presented with a 30-year history of progressive neck deformity that left her unable to see ahead and caused her to experience difficulty eating, drinking, and breathing on exertion. On examination, she exhibited a 90° fixed flexion deformity of the cervical spine, which was maximum at C-4; this was confirmed on imaging studies.

A two-level osteotomy was performed at C3–4 and C4–5 around the area of maximum spinal curvature, and the deformity was corrected by extending the head on its axis of rotation through the uncovertebral joints. The spine was stabilized using a Ransford loop. An excellent anatomical position was achieved, as was complete correction of the deformity.

A two-level midcervical osteotomy performed at the level of maximum spinal curvature in ankylosing spondylitis enables complete correction of severe fixed flexion deformity in a single procedure. Preservation of the uncovertebral joints allows smooth and safe correction of the deformity about their axis of rotation.
Calcifying pseudoneoplasms of the spine with myelopathy
Authors: Mayr Matthew T. , Hunter Stephen , Erwood Scott C. , Haid Regis W.
Published: May 2009

✓ The authors describe two cases of calcifying pseudoneoplasms, rare degenerative lesions that mimic tumor or infection. One case involved the cervical spine and the second the thoracic spine. Both patients experienced progressive myelopathy from extradural compression of the spinal cord. The radiological evaluation, pathological findings in the lesions, treatment, and follow up are described. Total or subtotal excision can relieve symptoms and prevent recurrence of this lesion.
Subacute posttraumatic ascending myelopathy after spinal cord injury
Authors: Belanger Eric , Picard Claude , Lacerte Daniel , Lavallee Pierre , Levi Allan D. O.
Published: May 2009

✓ Subacute posttraumatic ascending myelopathy is a rare disorder, unrelated to syrinx formation or mechanical instability, that may gradually emerge within the first 1 to 2 weeks after a spinal cord injury. The authors describe three patients with this syndrome and discuss its possible causes as well as its clinical presentation, imaging characteristics, treatment, and patient prognosis.
Embolization of spinal cord arteriovenous malformations with an ethylene vinyl alcohol copolymer dissolved in dimethyl sulfoxide (Onyx liquid embolic system)
Authors: Molyneux Andrew J. , Coley Stuart C.
Published: May 2009

✓ In this paper the authors describe the first use of a new liquid embolic agent (Onyx) to treat spinal cord arteriovenous malformations (AVMs). Because its properties make it more predictable to use than currently available liquid agents, the authors believe that this material has great potential in the endovascular management of both spinal cord and brain AVMs. This very promising agent merits further clinical study.
Split cord malformation with partial eventration of the diaphragm
Authors: Jindal Anupam , Kansal Somil , Mahapatra Ashok Kumar
Published: May 2009

✓ The authors describe the case of a 3-year-old girl who presented with a dorsal split cord malformation (SCM) and was found to have eventration of the diaphragm. Although the child did not undergo surgery for eventration, its presence suggests a need for careful preoperative planning and clinical evaluation to rule out or confirm the anomalies associated with spinal dysraphism or SCM.
Eosinophilic granuloma of the spine: early spontaneous disappearance of tumor detected on magnetic resonance imaging
Authors: Kamimura Mikio , Kinoshita Tetsuya , Itoh Hidehiro , Yuzawa Yohei , Takahashi Jun , Ohtsuka Kuniyoshi
Published: May 2009

✓ Two cases of eosinophilic granuloma (EG) of the spine associated with neurological deficits are presented. The patients were treated conservatively by using external fixation with a brace as well as bed rest. Neurological deficits and pain diminished and finally disappeared as the tumor mass decreased in size, as seen on magnetic resonance (MR) imaging. During the 5-year follow-up period no recurrence of the tumors was detected on MR images. Surgical treatment for spinal EG in children presenting with typical vertebra plana is not recommended except for those with severe or progressive palsy and for those in whom the disease requires differential diagnosis.
Intraspinal familial clear cell meningioma in a mother and child
Authors: Heth Jason A. , Kirby Patricia , Menezes Arnold H.
Published: May 2009

✓ The authors present a case of familial clear cell meningioma in which the proband is a child with an intraspinal tumor. The clear cell meningioma variant has recently been studied. The literature regarding clear cell meningioma is reviewed.
Traumatic intratumoral hemorrhage as the presenting symptom of a spinal neurinoma
Authors: Cohen Zvi R. , Knoller Nachshon , Hadani Moshe , Davidson Ben , Nass Dvora , Ram Zvi
Published: May 2009

✓ Intratumoral hemorrhage as the presenting symptom of spinal tumors is rare. The authors describe a patient who presented with rapidly progressing paraplegia 24 hours after sustaining a minor traumatic injury of the thoracic spine. Radiological evaluation demonstrated a low-thoracic intradural tumor that was resected and found to be a neurinoma in which severe intra- and peritumoral hemorrhage was revealed. The radiological, surgical, and pathological findings are presented and discussed.
A rare complication of hardware failure in neurostimulation
Authors: Sarwat Amr Mohamed , Karanth Kota Sadashiv , Sutcliffe John Christopher
Published: May 2009

✓ The authors report on a rare complication of neurostimulation. Two patients presented with a skin rash after undergoing neurostimulator implantation, and the implants were found to have faulty electrical insulation. The rash was centered over the source of current leak and disappeared when the problem was corrected.
The “open book” technique for preparation of the lumbar transverse process for posterolateral fusion
Authors: Deen H. Gordon
Published: May 2009

✓ A new technique is reported for preparation of the recipient graft bed for posterolateral intertransverse process fusion of the lumbar spine. The dorsal surface of each transverse process is reflected open like the pages of a book. This increases the surface area of cancellous bone in the recipient bed, thereby promoting better contact with the grafted bone. This maneuver also preserves much of the periosteal blood supply to the dorsal aspect of the transverse process and much of the cortical bone that would normally be drilled away during decortication. The technical details are described.
Intraoperative computerized tomography scanning to assess the adequacy of decompression in anterior cervical spine surgery
Authors: Freidberg Stephen R. , Pfeifer Bernard A. , Dempsey Peter K. , Tarlov Edward C. , Dube Michael A. , Day John D. , Machado Darlene E.
Published: May 2009

Object. The purpose of this study was to improve the accuracy of bone removal during anterior spinal surgery. Intraoperative computerized tomography (CT) scanning was used to assess the success of bone resection and permit immediate correction in the event of inadequate bone removal.

Methods. The Phillips Tomoscan M was used to obtain preoperative cervical scans before and after cervical bone resection was complete. The completeness of bone removal was assessed by the operating neurosurgeon by reviewing the postresection CT scan. If the bone removal was deemed inadequate, additional bone was removed using a high-speed drill. A CT scan was obtained after each subsequent decompression until adequate bone removal was achieved.

In 31 patients undergoing anterior cervical decompression intraoperative CT scanning was performed. Nineteen patients underwent corpectomy and 12 discectomy. Of the 31 patients, assessment of intraoperative CT scans obtained in 17 indicated further bone removal was required.

Conclusions. Intraoperative CT scanning to monitor bone removal during anterior cervical surgery is a valuable tool to ensure the adequacy of surgery.
Results and risk factors for anterior cervicothoracic junction surgery
Authors: Boockvar John A. , Philips Matthew F. , Telfeian Albert E. , O'Rourke Donald M. , Marcotte Paul J.
Published: May 2009

Object. Stabilization of the cervicothoracic junction (CTJ) requires special attention to the operative approach and biomechanical requirements of the fixation construct. In this study the authors assess the morbidity associated with the anterior approach to the CTJ and define risks that may lead to construct failure after anterior CTJ surgery.

Methods. Data obtained for 14 patients (six men and eight women, mean age 50.1 years) who underwent surgical stabilization of the CTJ via an anterior cervical approach were retrospectively reviewed to assess the anterior approach—related morbidity and the risks of construct failure. The mean follow-up period was 21.1 months. Four patients (29%) had previously undergone CTJ surgery; in 11 patients (64%) more than one motion segment was involved (two levels, six patients; three levels, four patients; four levels, one patient); allograft was placed in three (21%) of 14 graft sites; and anterior plates were used for reconstruction augmentation in eight patients (57%). Postoperatively all patients improved, although four patients had residual deficits or pain. Graft/plate failure, requiring surgical revision and/or halo placement, occurred in five patients (36%). One patient experienced transient recurrent laryngeal nerve palsy. Postoperatively, the authors classified patients into one of two groups: those in whom surgery was successful (nine cases) and those in whom it had failed (five cases). Analysis of the characteristics of these two groups revealed that male sex (p < 0.0365), multiple levels of involvement (p < 0.0378), and the use of allograft as compared with autograft (p < 0.0088) were significant risk factors for construct failure. Prior CTJ surgery (p < 0.053) tended to be associated with graft failure.

Conclusions: Findings of this study, in the setting of these factors, indicate that anterior reconstruction alone may not meet the biomechanical needs of this spinal region and that supplementary fixation may be considered to augment stabilization for fusion success.
Metastatic renal cell carcinoma of the spine: surgical treatment and results
Authors: Jackson Robert J. , Gokaslan Ziya L. , Arvinloh Shang-Chuin
Published: May 2009

Object. Renal cell carcinoma (RCC) is an aggressive malignancy that frequently metastasizes. When RCC metastasizes to the spine, significant pain and neurological dysfunction often follow. Because systemic therapy and radiotherapy have a limited effect in controlling spinal disease, surgery is frequently required; however, there are very few published series specifically addressing the role and benefits of the surgical treatment for this disease. The authors conducted a retrospective study to review their experience with the surgical treatment of metastatic RCC of the spine, paying particular attention to methodology and patient neurological status, pain relief, and survival.

Methods. Between January 1993 and April 1999, 79 patients (63 men and 16 women patients; average age 55 years, range 16–82 years) underwent 107 spinal operations for metastatic RCC. Indications for surgery included disabling pain (94 [88%] of 107 procedures) and/or neurological dysfunction (55 [51%] of 107 procedures). The anatomical location and extent of tumor determined the choice of an anterior, posterior, or combined surgical approach. Internal fixation was performed in all but three patients. Preoperative embolization was required in approximately one half of the patients. Radiotherapy was performed in 40 patients prior to surgery, and immuno- and chemotherapy were administered in 70 patients either pre- or postoperatively. After an average follow-up duration of 15 months, 57 patients had died. Kaplan—Meier analysis revealed a median postoperative survival of 12.3 months. Significant pain reduction, as indicated by a visual analog pain scale, was achieved in 84 (89%) of the 94 cases presenting with disabling pain. Neurological improvement was seen in 36 (65%) of the 55 patients. The major morbidity and 30-day mortality rates were 15% (16 of 107 procedures) and 2% (two of 107 procedures), respectively.

Conclusions. In selected patients with metastatic RCC of the spine, resection followed by stabilization can provide pain relief and neurological preservation or improvement.
Use of pedicle screw fixation in the management of malignant spinal disease: experience in 100 consecutive procedures
Authors: Fourney Daryl R. , Abi-Said Dima , Lang Frederick F. , McCutcheon Ian E. , Gokaslan Ziya L.
Published: May 2009

Object. Few reports are available on the use of pedicle screw fixation for cancer-related spinal instability. The authors present their experience with pedicle screw fixation in the management of malignant spinal column tumors.

Methods. Records for patients with malignant spinal tumors who underwent pedicle screw fixation at the authors' institution between September 1994 and December 1999 were retrospectively reviewed.

Results. Ninety-five patients with malignant spinal tumors underwent 100 surgeries involving pedicle screw fixation: metastatic spinal disease was present in 81 patients, and locally invasive tumors were demonstrated in 14 patients. Indications for surgery were pain (98%) and/or neurological dysfunction (80%). A posterior (48%) or a combined anterior—posterior (52%) approach was performed depending on the extent of tumor and the patient's condition. At the mean follow up of 8.2 months, 43 patients (45%) had died; median survival, as determined by Kaplan—Meier analysis, was 14.8 months. At 1 month postsurgery, self-reported pain had improved in 87% of cases (p < 0.001), which is a finding substantiated by reductions in analgesic use, and 29 (47%) of 62 patients with preoperative neurological impairments were functionally improved (p < 0.001). Postoperative complications were associated only with preoperative radiation therapy (p = 0.002) and with preexisting serious medical conditions (p = 0.04). In two patients asymptomatic violation of the lateral wall of the pedicle was revealed on postoperative radiography. The 30-day mortality rate was 1%.

Conclusions. For selected patients with malignant spinal tumors, pedicle screw fixation after tumor resection may provide considerable pain relief and restore or preserve ambulation with acceptable rates of morbidity and mortality.
Biomechanics of Grade I degenerative lumbar spondylolisthesis. Part 1: In vitro model
Authors: Crawford Neil R. , Çagli Sedat , Sonntag Volker K. H. , Dickman Curtis A.
Published: May 2009

Object. The authors sought to create and to evaluate an in vitro model of Grade I degenerative (closed-arch) spondylolisthesis.

Methods. The model of spondylolisthesis was created by two primary procedures: 1) resection of the disc; and 2) stripping of anterior and posterior longitudinal ligaments away from the vertebral bodies (VBs). In 13 vertebral levels obtained from three cadaveric lumbar spines, the tissues were resected sequentially in alternating order to determine the relative contribution of each resection to spinal instability. The entire specimens were loaded with nonconstraining torques and then individual levels were loaded with anteroposterior shear forces. The motion values were measured optoelectronically for each specimen at individual levels.

Conclusions. The integrity of the disc was more important than attachment of the ligaments to the VB, but the resection of both structures was necessary to achieve substantial destabilization. The structures of the spine are highly resilient, and destabilization is difficult to achieve without performing extensive resection. Using the techniques described in this paper to alter normal spines, a level of spinal instability (Grade I; 25% slippage) that may represent spondylolisthesis can be modeled in vitro.
Biomechanics of Grade I degenerative lumbar spondylolisthesis. Part 2: Treatment with threaded interbody cages/dowels and pedicle screws
Authors: Çagli Sedat , Crawford Neil R. , Sonntag Volker K. H. , Dickman Curtis A.
Published: May 2009

Object. The authors sought to determine the biomechanical effectiveness of threaded interbody cages or dowels compared with that achieved using pedicle screw instrumentation in resisting Grade I lumbar spine degenerative spondylolisthesis.

Methods. Thirty-three levels obtained from seven cadaveric lumbar spines were instrumented with cages or dowels, pedicle screw/rod instrumentation, or both. Entire specimens were loaded with nonconstraining torques. Each level was loaded with anteroposterior shear forces while an optical system was used to measure the specimen's motion at individual levels.

Pedicle screw/rods outperformed interbody cages and dowels in treating spondylolisthesis. Cages or dowels alone provided only moderate biomechanical stability, and their effectiveness depended heavily on the integrity of the ligaments and remaining annulus, whereas the success of pedicle screw fixation relied predominantly on the integrity of the bone for solid fixation. Little biomechanical difference was demonstrated between cages and dowels; both devices were susceptible to loosening with cyclic fatigue.

Conclusions. Biomechanically, cages or dowels alone were suboptimal for treating lumbar spondylolisthesis, especially compared with pedicle screw/rods. Threaded cages or dowels used together with pedicle screws/rods created the most stable construct.