bluuebunny/crossref_metadata_2025 huggingface dataset:
Surgical anatomy of the C-2 pedicle
Authors: Howington Jay U. , Kruse John J. , Awasthi Deepak
Published: May 2009

Object. The goal of this anatomical study was to investigate the surgical and radiographic anatomy of the C-2 pedicle in relation to transpedicular screw placement in occipitocervical stabilization and to establish anatomical guidelines for the placement of C-2 pedicle screws.

Methods. The C-2 pedicles in 10 cadaveric spines were evaluated using both computerized tomography (CT) scanning and manual measurements. The specimens were scanned; the mediolateral and rostrocaudal angulations of each pedicle were measured, with the midline sagittal plane and the inferior endplate of the C-2 facet, respectively, as references, and values were recorded in 1° increments by using a digital goniometer. The height, width, and length of the pedicles were also measured on the CT scans. Based on these measurements in conjunction with direct visualization of the C-2 pedicle through the C1–2 interlaminar space pedicle screws were then placed. The distances from the screw entry point to the midline, C2–3 joint line, and the medial aspect of the vertebral artery were also measured. Repeated CT scanning was then performed to assess screw placement.

The average pedicle height, width, and length measured 9.1 mm, 7.9 mm, and 16.6 mm, respectively, and the medial inclination and rostrocaudal angulation averaged 35.2° and 38.8°, respectively. The cortex of the pedicle was not violated in any of the 20 cadaveric specimens.

Conclusions. Adequate preoperative imaging studies in conjunction with direct visualization of the C-2 pedicle make transpedicular fixation safe and effective.
Pyogenic abscess of the filum terminale
Authors: Thomé Claudius , Krauss Joachim K. , Zevgaridis Dimitris , Schmiedek Peter
Published: May 2009

✓ Intradural spinal abscesses are rare. They are predominantly encountered as intramedullary abscesses of the spinal cord and infrequently as subdural lesions.

To their knowledge, the authors report the first case of a chronic pyogenic abscess of the terminal filum in an adult woman with kyphoscoliosis who presented with lumbar radiculopathies. Magnetic resonance imaging revealed a partly cystic intradural L3–4 mass that markedly enhanced after contrast administration. Laboratory signs of infection were absent. Intraoperatively a lobulated lesion observed within the terminal filum was tightly attached to neighboring nerve roots by fibrosis. On opening the cyst wall pus was revealed. Histological examination confirmed the diagnosis of a chronic abscess. Microbiological culture detected Staphylococcus aureus. Antibiotic therapy resulted in an uneventful postoperative course, with complete resolution of symptoms and radiologically demonstrated disappearance of the lesion. The pathogenesis and radiological features of the lesion are discussed.

Although extremely rare, a pyogenic abscess should be considered in the differential diagnosis of mass lesions of the cauda equina, especially in patients with preexisting spinal abnormalities. Surgical exposure, including drainage and biopsy sampling to rule out underlying tumor, combined with antibiotic treatment result in a favorable outcome.
Pedicular transvertebral fixation in severe grade spondylolisthesis
Authors: Chell Julian , Quinnell Richard C.
Published: May 2009

✓ The ideal treatment for spinal stabilization of Myerding Grade III–IV spondylolisthesis remains controversial, with a variety of techniques having been described. The authors report on a consecutive series of three adult patients with high-grade slippage who were treated with transvertebral pedicle fixation and standard spinal instrumentation, as both primary and revision procedures. There were no complications from the procedure, and a good outcome was achieved in all patients. The results at 4- to 8-year follow-up review are presented. This is a relatively simple and safe method of achieving spinal stabilization, which bypasses some of the problems caused by the associated anatomical distortion in high-grade spondylolisthesis and has good results at midterm follow up.
Cysts of the atlantoaxial joint: excellent long-term outcome after posterolateral surgical decompression
Authors: Zorzon Marino , Skrap Miran , Diodato Silvana , Nasuelli Davide , Lucci Bruno
Published: May 2009

✓ Articular cysts of the atlantoaxial joint are infrequently described and probably an underreported cause of upper cervical spinal cord compression. The authors report on two patients with cysts located posteriorly of the dens in whom a C-1 and partial C-2 hemilaminectomy with subtotal resection of the cyst provided adequate and stable decompression 1 year postoperatively. The clinical and magnetic resonance imaging features and the surgical approach are discussed after a review of the literature.
Atlantoaxial stability in ossiculum terminale
Authors: Liang Cheng-Loong , Lui Chun-Chung , Lu Kang , Lee Tao-Chen , Chen Han-Jung
Published: May 2009

✓ The authors describe a patient with ossiculum terminale. Thin-section three-dimensional computerized tomography reconstructions, magnetic resonance images, and radiographs of the cervical spine were obtained to evaluate the atlantoaxial stability and structures of the ossiculum terminale. Bone had formed between the ossicles and the body of the odontoid process, and good atlantoaxial stability was clearly demonstrated.
A craniocervical injury—induced syringomyelia caused by central canal dilation secondary to acquired tonsillar herniation
Authors: Takamura Yukio , Kawasaki Tsuyoshi , Takahashi Akira , Nunomura Katsuyuki , Tiba Kei , Hasunuma Masahiro , Itou Takeo
Published: May 2009

✓ The authors report on a 19-year-old man with an acquired tonsillar herniation caused by a craniocervical junction injury in which serial magnetic resonance (MR) images demonstrated patent and isolated segments of the central canal participating in the dilation and then formation of a cervical syrinx. The patient was involved in a motor vehicle accident; he developed tonsillar herniation as a complication of subarachnoid and epidural hemorrhage, predominantly observed around the cisterna magna and upper cervical canal. Repeated MR images obtained over an 11-month period indicated the formation and acute enlargement of the syrinx. Ten months after the accident, the patient presented with sensory disturbance in both upper extremities and spasticity due to syringomyelia. He underwent craniocervical decompressive surgery and duraplasty, which reduced the size of syringomyelia. The authors postulate that the patent central canal may play a role in determining the location of a syrinx remote from a focus of cerebrospinal fluid obstruction.
Use of a craniofacial miniplate for internal fixation in a young child with cervical instability
Authors: Li Veetai , Lopes Demetrius K. , Bennett Gregory J.
Published: May 2009

✓ Commercially available anterior cervical internal fixation devices are designed for placement in adults and older children. Use of these systems in preschool-aged children is precluded due to the small size of their cervical vertebral bodies (VBs). The authors describe a 2-year-old boy who suffered a C3–4 injury, resulting in complete ligamentous disruption. Because of the gross cervical instability, they elected to perform surgery via posterior and anterior approaches, supplemented with internal fixation, during the same operation. The purpose of the anterior internal fixation device is to deliver compressive forces onto the interbody graft and keep it in place, thus optimizing the potential for a successful fusion. Because of the discrepancy in size between the VBs and the plate and screws, however, the authors were unable to use any of the standard anterior cervical fixation devices. Instead, they implanted a craniofacial miniplate, and the patient was required to wear an external halo brace. The miniplate provided enough stability to allow for a solid fusion. The authors believe that this technique is a reasonable option in young children who require anterior cervical fixation.
Cervical epidural actinomycosis
Authors: Eftekhar Behzad , Ketabchi Ebrahim , Ghodsi Mohammad , Ahmadi Ali
Published: May 2009

✓ Cervical actinomycosis causing spinal cord compression is a rare clinical entity. In a review of the literature, the authors found only 13 cases with actinomycosis-related spinal neurological deficit.

The authors describe the case of a 26-year-old man who presented with neck pain and partial paresis of the upper limbs. Magnetic resonance imaging revealed a long cervical epidural enhancing lesion that extended from C-1 to T-2. The radiological findings resembled metastasis and other epidural infections. The patient was treated medically with penicillin and amoxicillin for 7 months and recovered neurologically.

The authors conclude that although cervical epidural actinomycosis is a rare clinical entity resembling metastasis and other infections in this region, it should be considered so that this unique infection can be diagnosed in the least invasive fashion and, whenever possible, unnecessary surgery can be avoided.
Hematogenous pyogenic facet joint infection of the subaxial cervical spine
Authors: Muffoletto Anthony J. , Nader Remi , Westmark Richard M. , Nauta Haring J. W. , Garges Kim J. , Hadjipavlou Alexander G.
Published: May 2009

✓ Two cases of hematogenous, pyogenic, subaxial cervical facet joint infection are reported, and the literature is reviewed. Infection of the cervical facet joint is a rarely diagnosed condition; only one case has been reported in the literature. Lumbar facet joint infections are also rare but more commonly reported. Approximately one fourth of facet joint infections in the lumbar spine are complicated by epidural abscess formation, which can lead to a neurological deficit. Because of the paucity of reports on cervical facet joint infections, the clinical characteristics of this entity are not well known.

Both patients presented with an acute onset of unilateral neck pain that radiated into the ipsilateral shoulder. Frank radicular pain was initially absent. Unilateral upper-extremity motor weakness that was attributed to associated epidural abscess or granulation tissue formation was also demonstrated in both patients. Leukocyte count and erythrocyte sedimentation rate were elevated in both cases. Magnetic resonance imaging was necessary to obtain an accurate diagnosis. Staphylococcus aureus was identified as the offending pathogen in both cases. Decompressive surgery and antibiotic therapy were required to cure the condition. One patient recovered completely and the other sustained a permanent motor deficit.

Hematogenous cervical facet joint infection is a rare clinical entity that has many characteristics in common with the more-common lumbar homolog. All three reported cases, however, have been complicated by epidural abscess or granulation tissue formation that has led to a neurological deficit. This finding suggests that a facet joint infection in the cervical spine may have a less benign clinical course than that in the lumbar spine.
Intraspinal cervical degenerative cyst
Authors: Hatem Ossama , Bedou Gérard , Négre Christian , Bertrand Jean Luis , Camo Jean
Published: May 2009

✓ The authors report three cases of cervical degenerative cysts causing medullary or radiculomedullary compression. Anatomicopathological examination confirmed the fibrous nature of the cyst wall and the absence of a synovial layer. One of the cysts was embedded in the ligamentum flavum, whereas the other two were most lateral and adherent to the facet joint. The physiopathogenesis of these cysts is discussed.
Results of applying ADCON-L gel after lumbar discectomy: the German ADCON-L study
Authors: Richter Hans-Peter , Kast Erich , Tomczak Rainer , Besenfelder Werner , Gaus Wilhelm
Published: May 2009

Object. Failed-back syndrome is still an unsolved problem. Use of ADCON-L gel, already commercially available, has been proven to reduce postoperative scarring in animal experiments. The authors of two controlled clinical studies have also shown positive results when applying the gel. They did not, however, establish patient-oriented endpoints. The authors report a study of ADCON-L in which they focus on patient-oriented endpoints.

Methods. Patients with lumbar disc herniation were randomized to an ADCON-L—treated or control group. Therapeutic success was evaluated using the validated Hannover Questionnaire on Activities of Daily Living (FFbH) 6 months after surgery. The study took place between November 14, 1996, and April 20, 1998, in eight neurosurgical centers in Germany. A total of 398 patients was recruited; 41 patients dropped out during follow up.

The mean functional FFbH score (100 points = all activities are possible without problem; 0 points = no activity is possible) was 78.5 points in the ADCON-L—treated group compared with 80 points in the control group. Furthermore, in terms of secondary outcome variables, the ADCON-L group did not have an advantage over the control group. Only the mean magnetic resonance imaging score showed a slight advantage of ADCON-L over the control group.

Conclusions. The authors found no positive effect of treatment with ADCON-L gel in patients in whom one-level lumbar microdiscectomy was performed. Because of its rather large sample size and its homogeneity, the study had sufficient power to detect even small differences between the two groups.
Frameless stereotaxy for anterior spinal procedures
Authors: Holly Langston T. , Bloch Orin , Obasi Chinyere , Johnson J. Patrick
Published: May 2009

Object. Intraoperative image guidance provides real-time three-dimensional visualization and has been successfully applied in many posterior spinal procedures. The feasibility of applying these techniques to anterior spinal surgery has not been studied systematically because the anterior spine, in contrast to the posterior spine, lacks distinct anatomical landmarks for registration. The authors sought to evaluate the practicality of performing stereotaxy in the anterior spine in a cadaveric model.

Methods. Unilateral C4—L4 pedicle screws were placed posteriorly in three cadaveric specimens to serve as unknown markers within each vertebral body. The specimens then underwent computerized tomography (CT) scanning, and the CT data were transferred to an optical tracking system. The anterior surface of the spine was registered for use with the stereotactic system by using a paired point—matching technique. Attached to a surgical drill, K-wires were placed under stereotactic guidance in a tip-to-tip orientation with the posterior pedicle screws. A second postoperative CT scan was obtained, and accuracy was determined by measuring the distance between the tips of the K-wire and pedicle screw.

The K-wires were placed tip to tip with pedicle screw markers in 57 vertebral levels. The mean registration error was 1.47 ± 0.04 mm, and when combined with the universal instrument registration error of 0.7 mm yielded an overall registration error of 2.17 ± 0.04 mm. The mean tip-to-tip distance for all K-wires placed was 2.46 ± 0.23 mm. The difference between the mean tip-to-tip distance and overall registration error was not statistically significant (p > 0.05), indicating that the K-wires were placed within the expected range of error.

Conclusions. The results of this study confirmed the feasibility of performing anterior stereotactic procedures throughout the spine. The accuracy of the findings in this study indicates that anterior stereotaxy should be applicable in clinical practice.
Effect of a prosthetic disc nucleus on the mobility and disc height of the L4–5 intervertebral disc postnucleotomy
Authors: Wilke Hans-Joachim , Kavanagh Sinead , Neller Sylvia , Haid Christian , Claes Lutz Eberhart
Published: May 2009

Object. Current procedures for treatment of degenerative disc disease may not restore flexibility or disc height to the intervertebral disc. Recently, a prosthetic device, intended to replace the degenerated nucleus pulposus, was developed. In this biomechanical in vitro test the authors study the effect of implanting a prosthetic nucleus in cadaveric lumbar intervertebral discs postnucleotomy and determine if the flexibility and disc height of the L4–5 motion segment is restored.

Methods. The prosthetic disc nucleus device consists of two hydrogel pellets, each enclosed in a woven polyethylene jacket.

Six human cadaveric lumbar motion segments (obtained in individuals who, at the time of death, were a mean age of 56.7 years) were loaded with moments of ± 7.5 Nm in flexion—extension, lateral bending, and axial rotation. The following states were investigated: intact, postnucleotomy, and after device implantation. Range of motion (ROM) and neutral zone (NZ) measurements were determined. Change in disc height from the intact state was measured after nucleotomy and device implantation, with and without a 200-N preload.

Conclusions. Compared with the intact state (100%), the nucleotomy increased the ROM in flexion—extension to 118%, lateral bending to 112%, and axial rotation to 121%; once the device was implanted the ROM was reduced to 102%, 88%, and 90%, respectively. The NZ increased the ROM to 210%, lateral bending to 173%, and axial rotation to 107% after nucleotomy, and 146%, 149%, 44%, respectively, after device implantation.

A 200-N preload reduced the intact and postnucleotomy disc heights by approximately 1 mm and 2 mm, respectively. The original intact disc height was restored after implantation of the device.

The results of the cadaveric L4–5 flexibility testing indicate that the device can potentially restore ROM, NZ, and disc height to the denucleated segment.
Comparison of spinal cord gray matter and white matter softness: measurement by pipette aspiration method
Authors: Ozawa Hiroshi , Matsumoto Takeo , Ohashi Toshiro , Sato Masaaki , Kokubun Shoichi
Published: May 2009

Object. Although the gray matter of the spinal cord has been thought to be softer than the white matter, there is no evidence to support this belief. Because the spinal cord is extremely soft, it has been difficult to measure the mechanical properties of the gray and white matter. The modulis of elasticity of the gray and white matter were measured in situ by using a pipette aspiration method.

Method. The spinal cord specimens were excised from Japanese white rabbits. Specimens were cut to display the surfaces of axial, frontal, and sagittal sections. The surfaces of the gray and white matter were aspirated using a 0.8-mm-inner-diameter glass pipette while monitoring with a video microscope, and the deformed length in the pipette was measured on a monitor. In each case the modulus of elasticity was calculated by comparing the relationship between the aspiration pressure and aspirated volume of the specimen with that determined by finite element analysis.

The moduli of elasticity of the gray and white matter were 3.4 ± 1.4 kPa (mean ± standard deviation) and 3.4 ± 0.9 kPa in the axial section, 3 ± 0.3 kPa and 3.5 ± 0.5 kPa in the frontal section, and 3.5 ± 0.9 kPa and 2.8 ± 0.4 kPa in the sagittal section, respectively.

Conclusions. No significant difference in modulus of elasticity was shown between the gray and white matter of the spinal in sections made in various directions.
Segmental neurofibromatosis—induced spinal cord compression
Authors: Muthukumar Natarajan
Published: May 2009

✓ Spinal segmental neurofibromatosis (NF) is a rare entity. To date, patients in reported cases of segmental NF (or NF5) have harbored neurofibromas involving the peripheral nerves only. The author reports a rare case of segmental NF that caused spinal cord compression in a 40-year-old woman who presented with a 6-month history of intercostal neuralgia. Examination revealed mild lower-extremity weakness and dysesthesia in the right-sided T-9 dermatome. Magnetic resonance imaging revealed three neurofibromas involving the T-9 region, which were excised, and the patient's neuralgic pain was resolved postoperatively. Traditionally, it has been believed that segmental NF involved only the peripheral nerves. The present case illustrates that although rare, spinal cord compression can also occur in patients with segmental NF.
Transoral resection of axial lesions augmented by intraoperative magnetic resonance imaging
Authors: Kaibara Taro , Hurlbert R. John , Sutherland Garnette R.
Published: May 2009

✓ Transoral decompression of the cervicomedullary junction may be compromised by a narrow corridor in which surgery is performed, and thus the adequacy of surgical decompression/resection may be difficult to determine. This is problematic as the presence of spinal instrumentation may obscure the accuracy of postoperative radiological assessment, or the patient may require reoperation. The authors describe three patients in whom high-field intraoperative magnetic resonance (MR) images were acquired at various stages during the transoral resection of C-2 disease that had caused craniocervical junction compression.

All three patients harbored different lesions involving the cervicomedullary junction: one each of plasmacytoma and metastatic breast carcinoma involving the odontoid process and C-2 vertebral body, and basilar invagination with a Chiari I malformation. All patients presented with progressive myelopathy. Surgical planning MR imaging studies performed after the induction of anesthesia demonstrated the lesion and its relationship to the planned surgical corridor. Transoral exposure was achieved through placement of a Crockard retractor system. In one case the soft palate was divided. Interdissection MR imaging revealed that adequate decompression had been achieved in all cases. The two patients with carcinoma required placement of posterior instrumentation for stabilization. Planned suboccipital decompression and placement of instrumentation were averted in the third case as the intraoperative MR images demonstrated that excellent decompression had been achieved.

Intraoperatively acquired MR images were instrumental in determining the adequacy of the decompressive surgery. In one of the three cases, examination of the images led the authors to change the planned surgical procedure. Importantly, the acquisition of intraoperative MR images did not adversely affect operating time or neurosurgical techniques, including instrumentation requirements.
Ectopic fingerlike structure in the thoracic region
Authors: Ishikawa Eiichi , Matsumura Akira , Enomoto Takashi , Tsurubuchi Takao , Nose Tadao
Published: May 2009

✓ The authors present a case of a rare cutaneous lesion resembling a human finger that protruded from the posterior thoracic region of a 7-month-old girl who was examined after the fingerlike protrusion was noted at birth. The protrusion measured 3 cm in length and 1 cm in diameter. It was located at the level of T-12 and was surrounded by angiomatous and lipomatous tissue. A computerized tomography scan demonstrated three bones in the protrusion, including deformities of the T-9 and T-10 and T-11 dysraphism. Magnetic resonance imaging revealed a hyperintense signal on the T1-weighted sequence and a hypointense signal on the T2-weighted sequence, which was visualized at the attachment to the spinal cord from T9–11. After removal of the fingerlike structure and subcutaneous mass, a T10–11 laminectomy and removal of the intradural mass were performed. Histological examination showed that the appendage was composed of nail, three bones, cartilage, and normal skin. This appendage can be recognized not only as a variant type of caudal appendage but as an ectopic finger and fingernail. The authors discuss the developmental differences among the protrusion in the present case and ordinary caudal appendages.
Total en bloc lumbar spondylectomy
Authors: Marmor Eric , Rhines Laurence D. , Weinberg Jeffrey S. , Gokaslan Ziya L.
Published: May 2009

✓ The authors describe a technique for total en bloc spondylectomy that can be used for lesions involving the lumbar spine. The technique involves a combined anterior—posterior approach and takes into account the unique anatomy of the lumbar spine. This technique allows for the en bloc resection of lumbar vertebral tumors, thus optimizing outcome while minimizing the risk of neurological injury. The technique is described in detail with the aid of neuroimaging studies, photographs of gross pathological specimens, and illustrations, and a discussion of other authors' experiences is provided for comparison.
Influence of an artificial cervical joint compared with fusion on adjacent-level motion in the treatment of degenerative cervical disc disease
Authors: Wigfield Crispin , Gill Steven , Nelson Richard , Langdon Ilana , Metcalf Newton , Robertson James
Published: May 2009

Object. The authors report the preservation of motion at surgically treated and adjacent spinal segments after placing an artificial cervical joint (ACJ) and they describe the influence of interbody fusion on changes in angulation occurring in the sagittal plane at adjacent levels in the treatment of cervical spondylosis.

Methods. The authors conducted a prospective nonrandomized study of patients in whom an ACJ was placed or autologous bone graft interbody fusion was performed. Angular measurements at levels adjacent to that surgically treated were calculated using plain flexion—extension radiographs obtained at 6-month intervals. Analyses of qualitative data, such as increase or decrease in adjacent-level motion, and the degree of disc degeneration were performed. Quantitative data were also analyzed. In the fusion group a significant increase in adjacent-level movement was demonstrated at the 12-month follow-up visit compared with the group of patients in whom ACJs were placed (p < 0.001). The increase in movement occurred predominantly at intervertebral discs that were preoperatively regarded as normal (p < 0.02). An overall reduction in adjacent-level movement was observed in patients who underwent joint replacement, although this was compensated for by the movement provided by the ACJ itself.

Conclusions. Fusion results in increased motion at adjacent levels. The increase in adjacent-level motion derives from those discs that appear radiologically normal prior to surgery. It remains unknown whether ACJs have a protective influence on adjacent intervertebral discs.
Bilateral open-door cervical expansive laminoplasty with hydroxyapatite spacers and titanium screws
Authors: Takayasu Masakazu , Takagi Teruhide , Nishizawa Toshihisa , Osuka Koji , Nakajima Takehiko , Yoshida Jun
Published: May 2009

Object. The authors report a simple method for bilateral open-door cervical expansive laminoplasty in which hydroxyapatite (HA) spacers are secured by titanium screws. A biomechanical study was also conducted to confirm the strength of the screw fixation.

Methods. A unilateral posterior approach was used to allow preservation of the posterior supporting elements (the posterior tension band) until the laminae were cut at the base. A bilateral open-door expansive laminotomy was then performed in standard fashion. Appropriate-sized HA spacers were selected, held with a specially designed holder, and placed between the split laminae. The screw holes were made in the laminae along the direction of the screw holes in the spacer, and two screws were inserted ventrolaterally to the laminae, resulting in instantaneous fixation. This procedure was performed in 15 patients; clinical results were successful, and there were no significant intraoperative complications. Follow-up radiological studies revealed no evidence of displacement of the spacers or screw backout. The screw artifacts observed on magnetic resonance imaging were minimal, allowing evaluation of the cervical spinal cord. The sagittal alignment of the cervical spine was well preserved. In the biomechanical studies the authors found that the screw fixation was of satisfactory strength, compared with other methods of fixation.

Conclusions. Bilateral open-door cervical expansive laminoplasty in which HA spacers are secured by titanium screws is a simple and quick method that yields sufficient fixation strength.
Acute traumatic central cord syndrome: magnetic resonance imaging and clinical observations
Authors: Collignon Frédéric , Martin Didier , Lénelle Jacques , Stevenaert Achille
Published: May 2009

Object. Acute traumatic central cord syndrome has been classically thought to be caused by a hemorrhage that primarily affects the central part of the spinal cord and that destroys the axons of the inner part of the corticospinal tract devoted to the motor control of the hands. Some authors, however, have proposed that its pathogenesis is based on the destruction of the motor neurons supplying the muscles of the hand. To test the validity of these two theories, the authors retrospectively studied the magnetic resonance (MR) images obtained in 18 cases of acute traumatic central cord syndrome (ATCCS) to assess the presence of intramedullary blood and to define the distribution of the abnormal signal intensities in the cervical spinal cord.

Methods. The authors used the American Spinal Injury Association (ASIA) motor scale to assess upper- and lower-limb deficits and to evaluate its metameric distribution. The abnormal intramedullary signal was then compared with the distribution of the motor deficit.

All MR imaging sessions performed in the acute stage revealed a hyperintense signal on T2-weighted sequences without any signal change suggesting the presence of intramedullary blood. The localization of this signal was distributed predominantly from the C3–4 to the C5–6 disc levels. The mean ASIA motor score was 74.3 of 100, with an unequal representation between the upper and lower limbs (32 of 50 compared with 42.3 of 50, respectively). The metameric distribution of the deficit was also unequal, with a major deficit in hand function (C8—T1) compared with the more proximal cord segments (5.2 of 10 compared with 7.8 of 10, respectively). This demonstrates the absence of any correlation between the hyperintense signal and the motor deficit distribution.

Conclusions. Acute traumatic central cord syndrome cannot be explained by the injury to the gray matter at the level of motor neurons supplying the hand muscles. In agreement with recently published data, the results of this series confirm the absence of intramedullary hemorrhage and corroborate the hypothesis that ATCCS may be explained by the impairment of the corticospinal tract, which can be affected globally.
Prospective multiple outcomes study of outpatient lumbar microdiscectomy: should 75 to 80% success rates be the norm?
Authors: Asch Harold L. , Lewis P. Jeffrey , Moreland Douglas B. , Egnatchik James G. , Yu Young J. , Clabeaux David E. , Hyland Andrew H.
Published: May 2009

Object. The authors assessed the efficacy and outcomes of lumbar microdiscectomy performed on an outpatient basis by administering six questionnaires before and at five time points after surgery. The results were compared with those reported in literature in which the success rates vary between 70% and 80% and in excess of 90%. The authors use the methodology and data derived from their study to evaluate critically the relevance of these two categories of success rates.

Methods. This is a prospective study of 212 consecutive, eligible patients who underwent outpatient microscopic discectomy for the treatment of lumbar disc herniation; no previous lumbar lesion had been treated. Data were collected from questionnaires given to the patients before and at five time points after surgery, including at a variable final follow-up examination (mean 2 years postoperatively). Data were collated and analyzed independently by individuals other than the operating surgeons.

In both bi- and multivariate analyses, only two preoperative parameters were prognostically significant. The first factor was Workers' Compensation status, which had a negative effect on outcome. The second factor was patient age, which also had a negative effect and was linear with increasing age between 25 years and 56 years—that is, the ages most commonly encountered in cases of herniated disc. Successful outcome rates were as follows: leg pain relief according to a visual analog scale (VAS), 80%; back pain relief (VAS), 77%; Oswestry Low Back Disability Index, 78%; satisfaction with the results of surgery, 76%; return to normal daily activities, 65%; and return to work, 61%.

Conclusions. The findings of this study support the evidence that lumbar microdiscectomy performed on an outpatient basis is a very safe and effective means of treating sciatic pain due to disc herniation. The authors believe that their outcome success rates of 75 to 80% are more realistic than those of 90% or more found in some reports.
Retroperitoneal lateral lumbar interbody fusion with titanium threaded fusion cages
Authors: Wolfla Christopher E. , Maiman Dennis J. , Coufal Frank J. , Wallace James R.
Published: May 2009

Object. Intertransverse arthrodesis in which instrumentation is placed is associated with an excellent fusion rate; however, treatment of patients with symptomatic nonunion presents a number of difficulties. Revision posterior and traditional anterior procedures are associated with methodological problems. For example, in the latter, manipulation of the major vessels from L-2 to L-4 may be undesirable. The authors describe a method for performing retroperitoneal lumbar interbody fusion (LIF) in which a threaded cage is placed from L-2 through L-5 via a lateral trajectory, and they also detail a novel technique for implanting a cage from L-5 to S-1 via an oblique trajectory. Although they present data obtained over a 2-year period in the study of 15 patients, the focus of this report is primarily on describing the surgical procedure.

Methods. The lateral lumbar spine was exposed via a standard retroperitoneal approach. Using the anterior longitudinal ligament as a landmark, the L2–3 through L4–5 levels were fitted with instrumentation via a true lateral trajectory; the L5—S1 level was fitted with instrumentation via an oblique trajectory. A single cage was placed at each instrumented level.

Fifteen symptomatic patients in whom previous lumbar fusion had failed underwent retroperitoneal LIF. Thirty-eight levels were fitted with instrumentation. There have been no instrumentation-related failures, and fusion has occurred at 37 levels during the 2-year postoperative period.

Conclusions. The use of retroperitoneal LIF in which threaded fusion cages are used avoids the technical difficulties associated with repeated posterior procedures. In addition, it allows L2—S1 instrumentation to be placed anteriorly via a single surgical approach. This construct has been shown to be biomechanically sound in animal models, and it appears to be a useful alternative for the management of failed multilevel intertransverse arthrodesis.
Usefulness of somatosensory evoked magnetic field dipole measurements by magnetoencephalography for assessing spinal cord function
Authors: Goto Takeo , Tsuyuguchi Naohiro , Ohata Kenji , Tsutada Tsuyoshi , Hattori Hideji , Shimogawara Masahiro , Matusaka Yasuhiro , Sakamoto Sinichi , Hara Mitsuhiro
Published: May 2009

Object. Objective assessment of sensory function disorders is difficult. In the present study, the authors investigated the possibility of assessing cervical myelopathy—induced sensory disorders by using magnetoencephalography (MEG) to measure somatosensory evoked magnetic fields (SSEMFs).

Methods. In 12 patients with cervical myelopathy, SSEMFs were measured before and after surgery by using a 160-channel helmet-type MEG system to stimulate the median nerve, and the intensity and latency of N20m (first response occurring 20 msec after stimulation) were then determined. Additionally, the severity of the sensory disorder was assessed before and after surgery by obtaining sensory scores determined using the Neurosurgical Cervical Spine Scale. Furthermore, in 11 healthy individuals (control group), the intensity and latency of N20m were measured in the same fashion. Analysis of the results showed that the preoperative intensity of N20m in the 12 patients with cervical myelopathy was significantly lower than that demonstrated in the control patients (p < 0.005, Student t-test). In addition, of six patients in whom sensory scores improved postoperatively, there were significant increases in the intensity of N20m (p < 0.005, paired t-test). Furthermore, there was a significant correlation between sensory scores and dipole intensity (p < 0.001, Spearman correlation coefficient by rank test).

Conclusions. Somatosensory evoked magnetic field measurements determined by MEG are useful in objectively and noninvasively assessing sensory disorders caused by cervical myelopathy.
Extreme lateral—transatlas approach for resection of the dens of the axis
Authors: Türe Uğur , Pamir M. Necmettin
Published: May 2009

Object. Various approaches have been described for resection of the dens of the axis, each of which has potential advantages and disadvantages. Anterior approaches such as the transoral route or its modifications are the most commonly used for resection of this structure. The transcondylar approach, however, which allows the surgeon to view the craniovertebral junction (CVJ) from a lateral perspective, has been introduced by Al-Mefty, et al., as an alternative approach. In this report, the authors describe the surgical technique of the extreme lateral—transatlas approach and their clinical experiences.

Methods. The authors first examined the surgical approach to the dens from a lateral perspective in five cadaveric heads. They found that removal of the lateral mass of the atlas provided adequate exposure for resection of the dens. Following this cadaveric study, the extreme lateral—transatlas approach was successfully performed at the authors' institution over a 1-year period (September 1998–August 1999) in five patients with basilar invagination due to congenital anomaly of the CVJ and rheumatoid arthritis. Furthermore, during the same procedure, unilateral occipitocervical fusion was performed following resection of the dens.

In all cases complete resection of the dens was achieved using the extreme—lateral transatlas approach. This procedure provides a sterile operative field and the ability to perform occipitocervical fusion immediately following the resection. No postoperative complications or craniocervical instability were observed. The mean follow-up period was 17.2 months (range 13–24 months).

Conclusions. The extreme lateral—transatlas approach for resection of the dens was found to be safe and effective. Knowledge of the anatomy of this region, especially of the V3 segment of the vertebral artery, is essential for the success of this procedure.
Effects of dexamethasone on apoptosis-related cell death after spinal cord injury
Authors: Zurita Mercedes , Vaquero Jesús , Oya Santiago , Morales Carmen
Published: May 2009

Object. The purpose of this study was to analyze the expression of F7–26 (Apostain) in injured spinal cord tissue, and the modifying effects of dexamethasone administration.

Methods. A total of 56 adult female Wistar rats were subjected to traumatic spinal cord injury (SCI) to induce complete paraplegia. These rats were divided into two groups according to whether they received dexamethasone (doses of 1 mg/kg daily) post-SCI. Injured spinal cord tissue was studied by means of conventional histological techniques, and Apostain expression was determined by immunohistochemical analysis at 1, 4, 8, 24, and 72 hours, and at 1 and 2 weeks after SCI in all the animals. Apostain-positive cells, mainly neurons and glial cells, were detected 1 hour after injury, peaking at 8 hours, after which the number decreased. One week after injury, apoptosis was limited to a few glial cells, mainly oligodendrocytes, and 2 weeks after injury there was no evidence of Apostain-positive cells. In the group of paraplegic rats receiving post-SCI intraperitoneal dexamethasone, there was a significant decrease in the number of Apostain-positive cells.

Conclusions. Analysis of the results indicated that apoptosis plays a role in the early period after SCI and that administration of dexamethasone decreases apoptosis-related cell death in the injured spinal cord tissue.
Bow hunter stroke caused by cervical disc herniation
Authors: Vates G. Edward , Wang Kevin C. , Bonovich David , Dowd Christopher F. , Lawton Michael T.
Published: May 2009

✓ Bow hunter stroke, which is characterized by transient vertebrobasilar ischemia brought on by head turning, is an unusual condition usually caused by structural abnormalities at the craniocervical junction. The authors present a case in which compression of the left vertebral artery (VA) at the C4–5 level was caused by a laterally herniated intervertebral disc. A 56-year-old man presented with a 6-month history of dizziness and syncope when he turned his head 45° or more to the left. Transcranial Doppler (TCD) ultrasonography demonstrated decreased blood flow through the left VA, and angiography revealed an occlusion of the left VA at the C4–5 level, both when the patient turned his head to the left. Via an anterior cervical approach, the VA canal was unroofed through the transverse foramina to decompress the left VA at C4–5; intraoperatively, the left VA was found to be compressed by a laterally herniated cervical disc fragment. To the best of the authors' knowledge this is the first report of a laterally herniated cervical disc causing bow hunter stroke. The use of TCD may be of value in the diagnosis and management of the disorder, and herniated cervical disc must be included in the roster of potential causes for this rare disease.
Increase of brain tumor oxygenation during cervical spinal cord stimulation
Authors: Clavo Bernardino , Robaina Francisco , Morera Jesús , Ruiz-Egea Eugenio , Pérez Juan L. , Macías David , Caramés Miguel Á. , Catalá Luis , Hernández M. Antonia , Günderoth Martina
Published: May 2009

✓ Malignant brain tumors have been shown to decrease O2 and blood flow resulting in hypoxia and low perfusion that in turn reduce radiation sensitivity and access by chemotherapeutic agents. Spinal cord stimulation (SCS) is a procedure that has been used quite successfully in the treatment of pain and ischemic syndromes. In the present study the authors applied the method and, with polarographic probes inserted in the tumor sites, measured the changes in tissue oxygenation and hypoxia in two separate tumor areas in three patients with high-grade astrocytomas. The results of the SCS indicated that overall tumor oxygenation increased by 90% (from 13.2 ± 9.4 mm Hg to 25.1 ± 9.6 mm Hg; p = 0.013); the percentage of moderately hypoxic values (< 10 mm Hg) decreased by 55% (from 48.6 ± 20.1% to 22 ± 13.3%; p = 0.026); and the percentage of considerably hypoxic values (< 5 mm Hg) decreased by 45% (from 28 ± 20.3% to 15.5 ± 15%; p = 0.018). In this report the authors describe a potential novel application of SCS, and the preliminary results suggest that tumor tissue oxygenation and hypoxia are significantly improved as a result. If these findings are confirmed, the method may be applicable as an adjuvant to radiotherapy and chemotherapy regimens.
Quadriplegia in a patient who underwent posterior fossa surgery in the prone position
Authors: Rau Cheng-Shyuan , Liang Cheng-Loong , Lui Chun-Chung , Lee Tao-Chen , Lu Kang
Published: May 2009

✓ Quadriplegia is a well-known complication of posterior fossa surgery performed while the patient is in the sitting position but is rarely associated with the prone position. A case of an 18-year-old man with a cerebellar medulloblastoma is described. There was no evidence of previous cervical disease. The patient suffered quadriplegia after undergoing surgery in the prone position. Postoperative magnetic resonance imaging demonstrated a long hyperintense C2—T1 lesion on T2-weighted sequences. The authors speculate that, during the prolonged period in which the neck was in hyperflexion, overstretching of the cervical spinal cord and compromise of its blood supply might have caused this devastating complication.
Massive growth of a meningioma into the brachial plexus and thoracic cavity after intraspinal and supraclavicular resection
Authors: Smith Edward R. , Ott Mark , Wain John , Louis David N. , Chiocca E. Antonio
Published: May 2009

✓ Extracranial meningiomas comprise approximately 2% of all meningiomas. Involvement of peripheral nerves by meningioma, either by a primary tumor or through secondary extension of an intraaxial lesion, is a much rarer entity; there have been only two reported primary brachial plexus meningiomas and one description of secondary involvement of the brachial plexus by extension of an intraaxial lesion. Although thoracic cavity meningiomas have been described in the literature, their pathogenesis is poorly understood. The authors present the case report of a 36-year-old man who was initially treated for a thoracic spinal meningioma that infiltrated the brachial plexus. After resection, progressive and massive growth with infiltration of the brachial plexus and pleural cavity occurred over a 5-year period despite radio- and chemotherapy. The case report is followed by a review of the literature of this rare entity.
Combined transarticular lateral and medial approach with partial facetectomy for lumbar foraminal stenosis
Authors: Hejazi Nedal , Witzmann Alfred , Hergan Klaus , Hassler Werner
Published: May 2009

✓ The authors performed a microsurgical combined transarticular lateral and medial procedure with partial facetectomy in 24 patients (16 men and nine women) with lumbar intervertebral foraminal stenosis to decompress the affected nerve root. The goal of this surgery was to maintain the integrity of the facet joint, to guarantee satisfactory exploration, and to obtain a sufficient decompression of the intervertebral foramen. Because only minimal bone resection is required, the risk of secondary instability induced by complete facetectomy is avoided. The clinical results of this procedure were excellent in the majority of cases. The mean follow-up period was 21.8 months.
A new technique for exposure of the cervical spine laminae
Authors: Shiraishi Tateru
Published: May 2009

✓ The author describes a new technique for exposure of the cervical spine laminae in which the attachments of the semispinalis cervicis and multifidus muscles to the spinous processes are left untouched. It provides a conservative exposure through which a diverse range of posterior cervical surgeries can be performed. In contrast to conventional cervical approaches, none of the muscular attachments to the spinous processes is compromised. In this paper the author describes the technical details and discusses the applications of the procedure.
Use of a titanium mesh cage for posterior atlantoaxial arthrodesis
Authors: Matsumoto Morio , Chiba Kazuhiro , Tsuji Takashi , Maruiwa Hirofumi , Toyama Yoshiaki , Ogawa Jun
Published: May 2009

✓ The authors placed titanium mesh cages to achieve posterior atlantoaxial fixation in five patients with atlantoaxial instability caused by rheumatoid arthritis or os odontoideum. A mesh cage packed with autologous cancellous bone was placed between the C-1 posterior arch and the C-2 lamina and was tightly connected with titanium wires. Combined with the use of transarticular screws, this procedure provided very rigid fixation. Solid fusion was achieved in all patients without major complications. The advantages of this method include more stable fixation, better control of the atlantoaxial fixation angle, and reduced donor-site morbidity compared with a conventional atlantoaxial arthrodesis in which an autologous iliac crest graft is used.