bluuebunny/crossref_metadata_2025_split huggingface dataset:
Initial stability of cervical spine fixation: predictive value of a finite element model
Authors: Pitzen Tobias R. , Matthis Dieter , Barbier Dragos D. , Steudel Wolf-Ingo 
Published: May 2009

✓ The purpose of this study was to generate a validated finite element (FE) model of the human cervical spine to be used to analyze new implants. Digitized data obtained from computerized tomography scanning of a human cervical spine were used to generate a three-dimensional, anisotropic, linear C5–6 FE model by using a software package (ANSYS 5.4). Based on the intact model (FE/Intact), a second was generated by simulating an anterior cervical fusion and plate (ACFP) C5–6 model in which monocortical screws (FE/ACFP) were used. Loading of each FE model was simulated using pure moments of ± 2.5 Nm in flexion/extension, axial left/right rotation, and left/right lateral bending. For validation of the models, their predicted C5–6 range of motion (ROM) was compared with the results of an earlier, corresponding in vitro study of six human spines, which were tested in the intact state and surgically altered at C5–6 with the same implants. The validated model was used to analyze the stabilizing effect of a new disc spacer, Cenius (Aesculap AG, Tuttlingen, Germany), as a stand-alone implant (FE/Cenius) and in combination with an anterior plate (FE/Cenius+ACFP). In addition, compression loads at the upper surface of the spacer were investigated using both models.
As calculated by FE/Intact and FE/ACFP models, the ROM was within 1 standard deviation of the mean value of the corresponding in vitro measurements for each loading case. The FE/Cenius model predicted C5–6 ROM values of 5.5° in flexion/extension, 3.1° in axial rotation (left and right), and 2.9° in lateral bending (left and right). Addition of an anterior plate resulted in a further decrease of ROM in each loading case. The FE/Cenius model predicted an increase of compression load in flexion and a decrease in extension, whereas in the FE/Cenius+ACFP model an increase of graft compression in extension and unloading of the graft in flexion were predicted.
The current FE model predicted ROM values comparable with those obtained in vitro in the intact state as well as after simulation of an ACFP model. It predicted a stabilizing potential for a new cage, alone and in combination with an anterior plate system, and predicted the influence of both loading modality and additional instrumentation on the behavior of the interbody graft.
A simple and reliable behavioral analysis of locomotor function after spinal cord injury in mice
Authors: Mikami Yuji , Toda Masahiro , Watanabe Masahiko , Nakamura Masaya , Toyama Yoshiaki , Kawakami Yutaka 
Published: May 2009

✓ To establish a simple and reliable method to assess the behavioral function after spinal cord injury (SCI) in mice, the authors used an automated animal movement analysis system, SCANET.
Two different SCI lesions were created in adult female BALB/c and C57BL/6 mice by transecting both the posterior columns and the left lateral and anterior funiculi or only the left lateral and anterior funiculi at T-8. Control mice underwent laminectomy only. The SCANET system consists of a cage equipped with two crossing sensor frames arranged at different heights, by which small (M1) and large (M2) horizontal movements and the vertical movement involved in rearing (RG) can be monitored. The authors assessed locomotor function by determining the M1, M2, and RG scores; to this end, they used the SCANET system and a previously established behavior test, the 21-point open-field Basso-Beattie-Bresnahan (BBB) Locomotor Rating Scale. The results indicated that the RG scores were significantly and consistently different between the spinal cord—injured and control mice, irrespective of the mouse strain or injury model, but that M1 and M2 scores were not. Moreover, there was a statistically positive correlation between the RG score and the BBB Scale score.
For the assessment of locomotor function after SCI, use of the SCANET sytem in behavioral analysis is simple and the method is highly reproducible. The analysis of vertical movement is useful for assessing the recovery of limb function in mice following thoracic hemisection.
Slitlike syrinx cavities: a persistent central canal
Authors: Holly Langston T. , Batzdorf Ulrich 
Published: May 2009

Object. The authors review their experience in the diagnosis and management of 32 patients with slitlike syrinx cavities.
Methods. There were 18 men and 14 women with a mean age of 40 years. Presenting symptoms that prompted magnetic resonance (MR) imaging evaluation were mechanical spinal pain (13 patients), radicular pain (seven patients), paresthesia (six patients), numbness (five patients), and muscle spasm (one patient). In 12 patients neurological examination demonstrated normal status, and in the remainder only minimal sensory or motor abnormalities were found. The mean diameter of the syrinx cavity was 2 mm (range 1–5 mm), and on average it covered three vertebral levels. The cavities were limited to the cervical region in 16 patients, the thoracic in 12, and both regions in four patients.
The mean follow-up time for changes in clinical condition and repeated MR imaging features were 38 and 32 months, respectively. Thirty-one patients were treated nonoperatively, and one was treated surgically. During the follow-up period clinical improvement was documented in six patients, worsened status in seven, and no change was demonstrated in the clinical status of 19 patients. None of the syrinx cavities changed in size. In 16 patients medical workup revealed alternative diagnoses that were determined to be the true causes of each patient's symptoms.
Conclusions. Slitlike cavities likely do not represent true syringomyelia but rather remnants of the central canal detected in a small percentage of adults. Review of the authors' experience indicates that these cavities are asymptomatic and are unlikely to change in size. They can be considered an incidental finding, and in many of these patients another condition explaining the patient's symptoms may be found.
Trauma-induced myelopathy in patients with ossification of the posterior longitudinal ligament
Authors: Matsunaga Shunji , Sakou Takashi , Hayashi Kyoji , Ishidou Yasuhiro , Hirotsu Masataka , Komiya Setsuro 
Published: May 2009

Object. In these prospective and retrospective studies the authors evaluated trauma-induced myelopathy in patients with ossification of the posterior longitudinal ligament (OPLL) to determine the effectiveness of preventive surgery for this disease.
Methods. The authors studied 552 patients with cervical OPLL, including 184 with myelopathy at the time of initial consultation and 368 patients without myelopathy at that time. In the former group of 184 patients retrospective analysis was performed using an interview survey to ascertain the relationship between onset of myelopathy and trauma. In the latter group of 368 patients prospective examination was conducted by assessing radiographic findings and noting changes in clinical symptoms apparent during regular physical examination. The follow-up period ranged from 10 to 32 years (mean 19.6 years).
In the retrospective investigation, 24 patients (13%) identified cervical trauma as the trigger of their myelopathy. In the prospective investigation, 70% of patients did not develop myelopathy over a follow-up period greater than 20 years (determined using the Kaplan—Meier method). Of the 368 patients without myelopathy at the time of initial consultation, only six patients (2%) subsequently developed trauma-induced myelopathy. Types of ossification in patients who developed trauma-induced myelopathy were primarily a mixed type. All patients in whom stenosis affected 60% or greater of the spinal canal developed myelopathy regardless of a history of trauma.
Conclusions. Preventive surgery prior to onset of myelopathy is unnecessary in most patients with OPLL.
Validity and reliability of the Short Form—36 in cervical spondylotic myelopathy
Authors: King Joseph T. , Roberts Mark S. 
Published: May 2009

Object. Validity (the extent to which a test measures what it is intended to measure) and reliability (the stability and reproducibility of measures of the same concept over time or across methods of gathering data) are important characteristics of any outcomes instrument. Generic outcomes instruments are designed for use in any population; however, their validity and reliability in particular diseases should be verified to ensure their appropriateness for use in that disease. In this study the authors assessed the validity and reliability of the Medical Outcomes Study Short Form—36 (SF-36), a generic outcomes instrument, in a population of patients with cervical spondylotic myelopathy (CSM).
Methods. The SF-36 was administered to a cohort of patients with CSM on an outpatient basis. Symptom-related data derived from a structured interview and physical examination findings were used to classify cases according to the myelopathy scales of Nurick, Cooper, Harsh, and a Western modification of the Japanese Orthopaedic Association (JOA). Construct validity was assessed by determining whether SF-36 scores varied in accordance with predefined hypotheses relating to the myelopathy scores by using the Cuzick nonparametric test for trend. The reliability of the SF-36 scores was assessed using Cronbach alpha.
Eighty-eight patients with CSM completed the SF-36 and interview. Construct validity was demonstrated by confirming the hypothesized relationship between SF-36 scales and the myelopathy scales of Nurick (p ≤ 0.003), Cooper leg subscale (p ≤ 0.012, except the general health perceptions domain [p = 0.091]), Harsh (p ≤ 0.016), and the motor component of the modified JOA (p ≤ 0.006). Reliability was demonstrated for all eight SF-36 domain scales and the physical component and mental component summary scales, in which Cronbach alpha satisfied the Nunnally criterion of 0.7.
Conclusions. The SF-36 provides valid and reliable data on patients with CSM.
Graft subsidence after instrument-assisted anterior cervical fusion
Authors: Tye Gary W. , Graham R. Scott , Broaddus William C. , Young Harold F. 
Published: May 2009

Object. Bone grafts used in anterior cervical fusion (ACF) may subside postoperatively. The authors reviewed a recent series in which instrument-assisted ACF was performed to determine the degree of subsidence with respect to fusion length, use of segmental screws, and patient smoking status, age, and sex.
Methods. Charts and implant records were reviewed for all 70 patients who underwent instrument-assisted ACF during a 2-year period. The procedures, grafting materials, plate types/lengths, and patient smoking status were recorded. The immediate postoperative and follow-up lateral radiographs were analyzed. The plate lengths and lengths of the fused segments were measured in a standardized fashion.
The mean intraoperative and follow-up fusion segment lengths were 54.3 and 51.9 mm, respectively. Greater subsidence occurred in multilevel fusions than in single-level fusions. There were noticeable changes in the position of plates or screws on 14 of 70 follow-up x-ray films. No new neurological deficits related to graft subsidence occurred, and the reoperation rate was 3%. There was no statistical relation between subsidence and the following variables: segmental fixation, smoking status, sex, age, or dowel size when corrected for length of the plate. Hardware migration correlated significantly with plate length in cases of two- and three-level fusions.
Conclusions. The length of a fusion segment decreases in the immediate weeks following instrument-assisted ACF. Construct length is the most important determinant of subsidence. When designing multilevel cervical constructs, consideration of the effects of graft subsidence may help to avoid hardware-related complications.
Bilateral decompression of lumbar spinal stenosis involving a unilateral approach with microscope and tubular retractor system
Authors: Palmer Sylvain , Turner Robert , Palmer Rosemary 
Published: May 2009

Object. The authors studied a consecutive series of patients with spinal stenosis in whom surgery was performed by a single surgeon who used a microscopic tubular retractor system (METRx-MD); patients underwent prospective evaluation involving radiography and magnetic resonance (MR) imaging.
The objective was to assess the feasibility and surgery-related efficacy of performing unilateral-approach bilateral decompression and utilization of METRx-MD instrumentation in patients with spinal stenosis.
Methods. Seventeen consecutive patients with spinal stenosis underwent bilateral decompression; surgery was performed via a unilateral approach using METRx-MD instrumentation. The procedures were performed on an outpatient basis after induction of general anesthesia. Preoperative and 3-month follow-up plain radiographs with flexion—extension views were obtained. Preoperative and postoperative MR imaging was also performed. All studies were assessed by a single radiologist blinded to the clinical results.
Twenty-two levels were surgically decompressed. The mean operative time was 90 minutes and the mean blood loss was 28 ml per level. Preoperatively stenosis was severe at 13 levels, moderate/severe at eight, and moderate at one. Postoperatively stenosis was absent at 13 levels, mild at seven, mild/moderate at one, and moderate at one. Preoperatively degenerative spondylolisthesis was documented in eight patients, with flexion—extension radiography revealing motion in three cases. On early (3-month) postoperative x-ray films there was no evidence of progression in any case. Grade I spondylolisthesis developed postoperatively in one patient, who remained asymptomatic.
Conclusions. Minimally invasive bilateral decompression and instrumentation-assisted fusion can be successfully performed via a unilateral approach in patients with acquired spinal stenosis; the procedure can be undertaken on an outpatient basis, with reasonable operative times, minimal blood loss, and acceptable morbidity rates.
Comparison of computerized tomography and direct visualization in thoracic pedicle screw placement
Authors: Rao Ganesh , Brodke Darrel S. , Rondina Matthew , Dailey Andrew T. 
Published: May 2009

Object. To validate computerized tomography (CT) scanning as a tool to assess the accuracy of thoracic pedicle screw placement, the authors compared its accuracy with that of direct visualization in instrumented cadaveric spine specimens.
Methods. A grading scale was devised to score the placement of the pedicle screw. The grades ranged from 0 to 3 depending on the extent to which the pedicle had been violated. One hundred fifty-five pedicles were fitted with instrumentation in eight cadaveric spines. A single observer graded the appearance of the screw based on CT scans (3-mm axial sections with 1-mm overlap) and direct visualization of the specimen. The authors arrived at a Kappa value of 0.51, which suggested only moderate agreement between the two measurement techniques. Whereas CT had a positive predictive value of 95%, it had a negative predictive value of 62%.
Conclusions. The authors thus conclude that although CT scanning is the most valid tool to assess the accuracy of thoracic pedicle screw placement, it tends to overestimate the number of misplaced screws.
Thoracic diastematomyelia with concurrent intradural epidermoid spinal cord tumor and cervical syrinx in an adult
Authors: Sheehan Jason P. , Sheehan Jonas M. , Lopes M. Beatriz , Jane John A. 
Published: May 2009

✓ Diastematomyelia is a rare entity in which some portion of the spinal cord is split into two by a midline septum. Most cases occur in childhood, but some develop in adulthood. A variety of concurrent spinal anomalies may be found in patients with diastematomyelia.
The authors describe a 38-year-old right-handed woman who presented with a 7-month history of lower-extremity pain and weakness on the right side. She denied recent trauma or illness. Sensorimotor deficits, hyperreflexia, and a positive Babinski reflex in the right lower extremity were demonstrated on examination.
Neuroimaging revealed diastematomyelia extending from T-1 to T-3, an expanded right hemicord from T-2 to T-4, and a C6–7 syrinx. The patient underwent T1–3 total laminectomies, resection of the septum, untethering of the cord, and excision of the hemicord lesion. The hemicord mass was determined to be an intramedullary epidermoid cyst; on microscopic evaluation the diastematomyelia cleft was shown to contain fibroadipose connective tissue with nerve twigs and ganglion cells. Postoperatively, the right lower-extremity pain, weakness, and sensory deficits improved.
Diastematomyelia can present after a long, relatively asymptomatic period and should be kept in the differential diagnosis for radiculopathy, myelopathy, tethered cord syndrome, or cauda equina syndrome. Numerous spinal lesions can be found in conjunction with diastematomyelia. To the authors' knowledge, this is the first case in which a thoracic epidermoid cyst and cervical syrinx occurred concurrently with an upper thoracic diastematomyelia. Thorough neuraxis radiographic evaluation and surgical treatment are usually indicated.
Preoperative embolization and intraoperative cryocoagulation as adjuncts in resection of hypervascular lesions of the thoracolumbar spine
Authors: Nader Remi , Alford Brent T. , Nauta Haring J. W. , Crow Wayne , Vansonnenberg Eric , Hadjipavlou Alexander G. 
Published: May 2009

Object. The purpose of this study was twofold. First the authors evaluated preoperative embolization alone to reduce estimated blood loss (EBL) when resecting hypervascular lesions of the thoracolumbar spine. Second, they compared this experience with intraoperative cryotherapy alone or in conjunction with embolization to minimize further EBL.
Methods. Twelve patients underwent 13 surgeries for hypervascular spinal tumors. In 10 cases the surgeries were augmented by preoperative embolization alone. In one patient, two different surgeries involved intraoperative cryocoagulation, and in one patient surgery involved a combination of preoperative embolization and intraoperative cryocoagulation for tumor resection. When cryocoagulation was used, its extent was controlled using intraoperative ultrasonography or by establishing physical separation of the spinal cord from the tumor.
In the 10 cases in which embolization alone was conducted, intraoperative EBL in excess of 3 L occurred in five. Mean EBL was of 2.8 L per patient. In one patient, who underwent only embolization, excessive bleeding (> 8 L) required that the surgery be terminated and resulted in suboptimum tumor resection. In another three cases, intraoperative cryocoagulation was used alone (in two patients) or in combination with preoperative embolization (in one patient). In all procedures involving cryocoagulation of the lesion, adequate hemostasis was achieved with a mean EBL of only 500 ml per patient. No new neurological deficits were attributable to the use of cryocoagulation.
Conclusions. Preoperative embolization alone may not always be satisfactory in reducing EBL in resection of hypervascular tumors of the thoracolumbar spine. Although experience with cryocoagulation is limited, its use, in conjunction with embolization or alone, suggests it may be helpful in limiting EBL beyond what can be achieved with embolization alone. Cryocoagulation may also assist resection by preventing spillage of tumor contents, facilitating more radical excision, and enabling spinal reconstruction. The extent of cryocoagulation could be adequately controlled using ultrasonography or by establishing physical separation between the tumor and spinal cord. Additionally, somatosensory evoked potential monitoring may provide early warning of spinal cord cooling.
Surgical treatment of spinal deformities associated with neurofibromatosis Type 1
Authors: Halmai Vilmos , Domán István , de Jonge Tamás , Illés Tamás 
Published: May 2009

Object. In 10 to 50% of cases with neurofibromatosis, skeletal disorders are present, mainly as various deformities of the spine. These deformities can be divided into dystrophic and nondystrophic groups depending on the absence or presence of bone dystrophy. The nondystrophic curves are highly similar to those in idiopathic scoliosis, whereas the dystrophic curves are manifested early and, by progressing inexorably, may lead to neurological symptoms. In this article the authors report on a series of 12 patients (11 with dystrophic and one with nondystrophic deformities) who underwent surgical treatment.
Methods. In the case with a nondystrophic curve, posterolateral instrumentation-assisted fusion was performed. A curvature correction of 70% was achieved in the frontal plane, and at the 2-year follow-up examination neither bone dysplasia nor pseudarthrosis was observed. In the cases with dystrophic curves, preoperative traction for 3 weeks was applied; anterior surgical release was then performed, as was two-stage posterior instrumentation-assisted fusion. In the cases of thoracic kyphoscoliosis in which this treatment protocol was performed, the mean scoliosis correction was 66%, whereas the mean decrease in kyphotic angle was 34.5°. In the cases with thoracolumbar and lumbar curves, the mean correction in the frontal plane was 69.8°, whereas the mean preoperative lumbar kyphosis of 42° was corrected to a mean lordotic angle of 23°. Postoperatively, no hook dislocation was detected. A neurological complication was observed in one case.
Conclusions. The surgical treatment of dystrophic curves always included 360° fusion and the use of a tibial corticocancellous graft, which must be placed on the concave side of the curve in the frontal plane, the graft thereby providing biomechanical support.