bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tarlov cysts: a study of 10 cases with review of the literature
Authors: Voyadzis Jean-Marc , Bhargava Parul , Henderson Fraser C. 
Published: May 2009

Object. Tarlov or perineurial cysts are lesions of the nerve root most often found in the sacral region. Although there is agreement that asymptomatic Tarlov cysts should be followed, it is still debated whether patients with symptomatic Tarlov cysts should be treated surgically. The authors assessed the outcome and efficacy of cyst wall resection in 10 patients with symptomatic Tarlov cysts. The medical literature is reviewed, theories of origin are evaluated, and suggestions as to their cause and pathogenesis are offered.
Methods. Ten consecutive patients harboring symptomatic Tarlov cysts were treated by the senior author between 1989 and 1999. All patients were assessed for neurological deficits and pain by neurological examination and visual analog scale, respectively. Computerized tomography myelography was performed in all patients to diagnose delayed filling of the cysts. A sacral laminectomy with resection of the sacral cyst or cysts was performed in all patients. Resected material from eight of 10 patients was submitted for histopathological evaluation. Seven (70%) of 10 patients obtained complete or substantial resolution of their symptoms, with an average follow up of 31.7 months. All of these patients had Tarlov cysts larger than 1.5 cm in diameter, producing radicular pain or bladder and bowel dysfunction. Three (30%) of 10 patients experienced no significant improvement. All three patients harbored Tarlov cysts smaller than 1.5 cm in diameter, producing nonradicular pain. Histopathological examination was performed on specimens from eight of 10 patients, which demonstrated nerve fibers in 75% of cases, ganglion cells in 25% of cases, and evidence of old hemorrhage in half.
Conclusions. Large cysts (> 1.5 cm) and the presence of associated radicular symptoms strongly correlate with excellent outcome. Tarlov cysts may result from increased hydrostatic pressure and trauma.
Microendoscopic posterior cervical laminoforaminotomy for unilateral radiculopathy: results of a new technique in 100 cases
Authors: Adamson Tim E. 
Published: May 2009

Object. In this report the author presents surgery-related outcomes after application of a new technique. A posterior microendoscopic laminoforaminotomy was used for the surgical treatment of unilateral cervical radiculopathy secondary to intervertebral disc herniations and/or spondylotic foraminal stenosis. The results of this procedure are compared with those achieved using traditional laminoforaminotomy and anterior cervical discectomy with or without fusion.
Methods. One hundred consecutive patients who experienced unilateral cervical radicular syndromes, which were refractory to conservative therapy, and in whom imaging studies had confirmed lateral canal or foraminal compression, underwent surgical treatment. An endoscopy-assisted posterior laminoforaminotomy was performed using a microendoscopic visualization system for removal of herniated disc and foraminal decompression while the patient was in the sitting position.
Excellent or good results were obtained in 97 patients, who returned to their preoperative employment and baseline level of physical activity. One patient returned to work but was unable to perform at baseline level; two patients returned to prior sedentary work but continued to have some activity-related pain and paresthesias. Two patients reported experiencing intermittent paresthesias or numbness, but this did not limit their activities. There were two cases of dural punctures, one case of superficial wound infection, and no deaths.
Conclusions. The microendoscopic posterior laminoforaminotomy is an effective alternative for the treatment of unilateral cervical radiculopathy secondary to lateral or foraminal disc herniations or spondylosis. In this group of patients, it is preferable because it does not require the sacrifice of a cervical motion segment, has a low incidence of complications, and is associated with a much quicker return to unrestricted full activity than that obtained with other techniques.
Screw placement in transoral atlantoaxial plating systems: an anatomical study
Authors: Kandziora Frank , Schulze-Stahl Niels , Khodadadyan-Klostermann Cyrus , Schröder Ralf , Mittlmeier Thomas 
Published: May 2009

Object. The placement of an anterior atlantoaxial plate after transoral odontoid resection has been described by Harms. Recently, the authors of biomechanical and clinical studies have shown that this procedure, especially in combination with posterior wiring, is a good alternative to established, isolated posterior atlantoaxial fixation techniques. Reports on the anatomy of the atlas and axis primarily focus on the posterior surgical approach. Scarce research regarding the quantitative anatomy of the anterior aspect of C-1 and C-2 has been reported. This study was undertaken to measure relevant dimensions of C-1 and C-2 and their relation to the anterior transoral approach. The aim of the study was to determine “safe zones” for screw placement in anterior atlantoaxial plate fixation.
Method. Fifty human dry C-1 and C-2 vertebrae were obtained for direct anatomical, radiographic, and computerized tomography (CT) measurements. Thirty-two linear and four angular parameters were evaluated. All measurements were made using a digital caliper, ruler, or goniometer. Anatomical measurements were correlated with radiographic (anteroposterior, lateral, and craniocaudal) and CT (0.5-mm-slice thickness) measurements of the corresponding vertebrae. Additionally, bone mineral density (BMD) measurements of C-1 and C-2 were obtained in 20 patients.
A safe zone for anterior screw placement in an atlas of bilateral trapezoid shape could be characterized. The average medial and lateral height of the trapezoid was 4.1 ± 1.01 mm (range 1.4–6.7 mm) and 12.9 ± 1.73 mm (range 8.7–17.4 mm), respectively. The distance between the sagittal plane and the medial and lateral walls of the trapezoid was 10.2 ± 1.42 mm (range 8.9–12.8 mm) and 23.5 ± 2.98 mm (range 21.7–30.7 mm), respectively. The average depth of the lateral masses was 22.3 ± 2.04 mm (range 17.0–26.7 mm) in the sagittal plane. The average BMD in the safe zone of C-1 was 0.89 ± 0.11 g/cm3 (range 0.75–1.01 g/cm3). Bone mineral density measurements at C-2 revealed a spheroid zone of low density at the basis of the dens (0.68 ± 0.09 g/cm3). In contrast, high zones of BMD were found near the articular surfaces (C1–2: 0.97 ± 0.11 g/cm3; C2–3: 0.94 ± 0.12 g/cm3). The safe zone for anterior axis screw placement was V-shaped, limited cranially by a zone of low bone density and laterally by the vertebral artery groove. Correlations between radiographic and anatomical measurements were generally good (r2 = 0.78–0.95), but they were higher between CT and anatomical measurements (r2 = 0.86–0.99).
Conclusions. A quantitative understanding of the anterior anatomy of C-1 and C-2 is necessary when considering anterior atlantoaxial plate fixation after transoral odontoid resection. In this study the authors defined safe zones for anterior atlas and axis screw placement. The anterior atlantoaxial plate, as originally described by Harms, only partially respects these safe zones.
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.
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.
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.
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.