bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulation of nitric oxide homeostasis in a mouse model of spinal cord injury
Authors: Genovese Tiziana , Mazzon Emanuela , Mariotto Sofia , Menegazzi Marta , Cardali Salvatore , Conti Alfredo , Suzuki Hisanori , Bramanti Placido , Cuzzocrea Salvatore
Published: January 2008

Object

A traumatic spinal cord injury (SCI) immediately induces primary damage, and this is followed by secondary damage characterized by a series of events among which is a progressive extension of cell death within the damaged tissue. In this study, the authors investigated the role of inducible nitric oxide synthase (iNOS) in an experimental model of SCI in mice.

Methods

In wild-type (iNOS+/+) mice, SCI rapidly induced an inflammatory response as shown by nitrotyrosine formation, activation of the nuclear enzyme poly(adenosine diphosphate-ribose) polymerase (PARP), neutrophil infiltration, and spinal cord tissue histopathological changes, indicating the involvement of iNOS-derived massive amounts of NO in SCI.

Conclusions

Genetic inhibition of iNOS, however, resulted in a significant reduction in secondary damage, and this therapeutic efficacy was associated with the prevention of an SCI-induced drop in neuronal and endothelial NOS activity.
Hemangiopericytoma-like synovial sarcoma of the lumbar spine
Authors: Sakellaridis Nikolaos , Mahera Helen , Pomonis Spiros
Published: January 2008

✓The purpose of this report is to demonstrate that synovial sarcoma should be included in the differential diagnosis of tumors originating from the lumbar spine, especially if they show hemangiopericytoma-like pathological characteristics. A synovial sarcoma is a mesenchymal spindle cell tumor that displays variable epithelial differentiation including glandular formation. It is unrelated to a synovium. More than 80% of these lesions arise in the deep soft tissue of the extremities. The tumor frequently arises adjacent to joints or tendon sheaths. The authors describe a young woman with a hemangiopericytoma-like tumor of the lumbar spine. During repeated operation, this lesion was shown to be a synovial sarcoma, which had invaded the dura mater. The tumor metastasized to the mediastinum and the intradural cervical spine and, finally, to the brain and the lungs. To the authors’ knowledge, this is the first reported case of a synovial sarcoma originating from the lumbar spine.
Biomechanical study of thoracolumbar junction fixation devices with different diameter dual-rod systems
Authors: Chang Ung-Kyu , Lim Jesse , Kim Daniel H.
Published: January 2008

Object

Advances in the design of a smaller-diameter rod system for use in the thoracolumbar region prompted the authors to undertake this biomechanical study of two different thoracolumbar implants.

Methods

In vitro biomechanical testing was performed using human cadaveric spines. All specimens were loaded to a maximum moment of 5 Nm with 300-N axial preload in six modes of motion. Two types of anterior implants with different rod diameters were applied to intact T10–12 specimens in two groups. The loading was repeated and the range of motion (ROM) was measured. A T-11 corpectomy was then performed and a strain gauge–mounted carbon fiber stackable cage was implanted. The ROM and compression force on the cage were measured, and the mean values were compared between these two groups.

With stabilization of the intact spine, ROM decreased least in extension and greatest in bending compared with the intact specimens. After corpectomy and stabilization, ROM increased in extension by 104.89 ± 53.09% in specimens with a 6.35-mm rod insertion and by 83.81 ± 16.96% in those with a 5.5-mm rod, respectively; in flexion, ROM decreased by 26.98 ± 27.43% (6.35 mm) and by 9.59 ± 15.42% (5.5 mm), respectively; and in bending and rotation, both groups each showed a decrease in ROM. The load sharing of the cage was similar between the two groups (the 6.35-mm compared with 5.5-mm rods): 47.44 and 44.73% (neutral), 49.16 and 39.02% (extension), 61.90 and 56.88% (flexion), respectively.

Conclusions

There were no statistical differences in the ROM and load sharing of the cage when either the 6.35-or 5.5-mm-diameter dual-rod was used.
Biomechanical evaluation of the ventral and lateral surface shear strain distributions in central compared with dorsolateral placement of cages for lumbar interbody fusion
Authors: Sohn Moon-Jun , Kayanja Mark M. , Kilinçer Cumhur , Ferrara Lisa A. , Benzel Edward C.
Published: January 2008

Object

The purpose of this study was to measure and compare the ventral and lateral surface strain distributions and stiffness for two types of interbody cage placement: 1) central placement for anterior lumbar interbody fusion (ALIF); and 2) dorsolateral placement for extraforaminal lumbar interbody fusion (ELIF).

Methods

Two functional spine units were obtained for testing in each of 13 cadaveric spines, yielding 26 segments (three of which were not used because of bone abnormalities). Bilateral strain gauges were mounted adjacent to the endplate on the lateral and ventral walls of each vertebral body in the 23 motion segments. Each segment was cyclically tested in compression, flexion, and extension in the following conditions: while intact, postdiscectomy, and instrumented with interbody fusion cages placed using both insertion techniques.

No significant differences were observed between ALIF and ELIF in compressive stiffness, bending stiffness in flexion and extension (p ≥ 0.1), ventral and lateral strain distribution during the intact tests (p ≥ 0.24), and during the flexion tests after fusion (p ≥ 0.22). In compression, higher ventral and lower lateral strain was observed in the ALIF than in the ELIF group (ventral, p = 0.05; lateral, p = 0.04), and in extension, higher ventral (p = 0.01) and higher lateral strain (p = 0.002) was observed in the ELIF than in the ALIF group.

Conclusions

Preservation of the ventral anulus and dorsolateral placement of the interbody cages during ELIF allow alternate load transfer pathways through the dorsolateral vertebral wall and ventral anulus that are not observed following ALIF. These may be associated with a lower incidence of subsidence and a higher rate of fusion due to a more concentrated application of bone healing–enhancing compression forces during the fusion and healing process.
Conus medullaris syndrome without lower-extremity involvement in L-1 burst fractures
Authors: Chou Dean , Hartl Roger , Sonntag Volker K. H.
Published: January 2008

✓ Conus medullaris injury from burst fractures is known to occur in conjunction with other neurological deficits, including lower-extremity motor weakness or sensory changes. Rarely does an isolated conus medullaris injury occur from an extradural cause without other neurological deficits. The authors report four cases of L-1 burst fractures in which conus medullaris dysfunction was the sole neurological injury in the absence of lower-extremity involvement.
Implantation of an empty carbon fiber cage or a tricortical iliac crest autograft after cervical discectomy for single-level disc herniation: a prospective comparative study
Authors: Schils Frédéric , Rilliet Benedict , Payer Michael
Published: January 2008

Object

The authors conducted a study to evaluate and compare prospectively the implantation of either an empty carbon fiber composite frame cage (CFCFC) or an iliac crest autograft after anterior cervical discectomy (ACD) for cervical disc herniation with monoradiculopathy.

Methods

Thirty-six consecutive patients with one-level radiculopathy due to single-level cervical disc herniation were treated by ACD, and implantation of either an empty CFCFC (24 patients) or an iliac crest autograft (12 patients). Radiological and clinical assessments were performed preoperatively, immediately postoperatively; and at 3, 6, and 12 months postoperatively. Fusion, at the 12-month follow-up examination was demonstrated in 96% of the patients in the cage group and in 100% of those in the autograft group. The mean anterior intervertebral body height was 3.7 mm preoperatively and 3.9 mm at 12 months in the CFCFC, and 4.1 and 3.8 mm, respectively, in the autograft group. In cage-treated patients, neck pain, as measured using the visual analog scale (VAS) (Score 0 = minimum; 10 = maximum) decreased from 6.4 preoperatively to 2.0 at 12 months, and radicular pain, decreased from 8.4 preoperatively to 1.5 at 12 months. In the autograft group, neck pain changed from a mean preoperative VAS score of 7.2 to 2.5 at 12 months, and radicular pain decreased from a preoperative mean of 7.8 to 1.4 at 12 months. Analysis of the 12-Item Short Form Health Survey domains and the Oswestry Disability Index scores indicated a significant improvement in both the Physical and Mental Component Summary domains in both groups.

Conclusions

Implantation of an empty CFCFC or a tricortical iliac crest autograft after ACD are safe and reliable options for the treatment of cervical disc herniation causing one-sided radiculopathy. Both procedures produced equally satisfying clinical and radiological results, leading to a high fusion rate and maintaining intervertebral height. Implantation of an empty CFCFC has the advantages of avoiding any donor site morbidity and requiring a significantly shorter operative time.
Lymphatic fluid fistula: an extremely rare complication of posterior lumbar transpedicular screw fixation
Authors: Raco Antonino , Russo Natale , Landi Alessandro , Dazzi Mauro , Carlesimo Bruno
Published: January 2008

✓ The authors describe the unique case of a patient who had undergone posterior stabilization of the lumbar spine complicating the course of a lymphatic fistula. A lymphatic fistula is a rare complication of posterior lumbar surgery. Predisposing factors include individual anatomy, scarring adherences due to previous abdominal operations or surgical maneuvers deep in the plane of the transverse processes. Because the onset of lymphatic fistulas is subtle, and because they are associated with a high mortality rate and require multidisciplinary treatment, care is needed to avoid misdiagnosing these lesions as the more common cerebrospinal fluid fistula.
Anterior expandable strut cage replacement for osteoporotic thoracolumbar vertebral collapse
Authors: Uchida Kenzo , Kobayashi Shigeru , Nakajima Hideaki , Kokubo Yasuo , Yayama Takafumi , Sato Ryuichiro , Timbihurira Godfrey , Baba Hisatoshi
Published: January 2008

Object

The authors investigated the usefulness of using an expandable cage strut in anterior reconstruction after osteoporotic vertebral collapse in patients with neurological deficits.

Methods

Twenty-eight patients who had undergone expandable cage strut–augmented anterior thoracolumbar reconstruction participated in a follow-up review for a mean of 4.9 years. Radiographs were reviewed for kyphosis, lateral tilt of the implant, cage subsidence, the presence of a solid fusion mass, and instrumentation failure. Changes in neurological status and visual analog scale (VAS) pain score, as well as technique-related complications, were examined.

The mean angles ± the standard deviations of kyphosis correction 4 to 6 weeks after surgery and at final follow-up examination were 10.4 ± 7.6° and 5.6 ± 6.0°, respectively. The mean subsidence of the expandable cage within the adjacent vertebrae was 2.5 ± 3.0 mm at the final follow-up examination. Neurological improvement at the final follow up was more significant in patients with Type 1 (wedge-type) than Type 2 (flat-type) (p = 0.037) or Type 3 (concave-type) (p = 0.006) vertebral collapse. Follow-up VAS scores were significantly higher in patients with Type 1 than Type 3 collapse (p = 0.012). In all cases the authors observed solid union with incorporation of the cage. There were no surgery-related complications.

Conclusions

An expandable titanium cage strut seems useful in vertebral body replacement in patients with osteoporotic thoracolumbar collapse. Favorable results were obtained in cases of Type 1 collapse (wedge type) in which the middle and posterior columns remained comparatively intact.
Anatomical considerations for cervical pedicle screw insertion: the use of multiplanar computerized tomography reconstruction measurements
Authors: Chazono Masaaki , Soshi Shigeru , Inoue Takeshi , Kida Yoshikuni , Ushiku Chikara
Published: January 2008

Object

The purpose of this study was to evaluate the linear and angular parameters of the vertebral body (VB) required for cervical pedicle screw (CPS) insertion by using multiplanar computerized tomography (CT) reconstructions.

Methods

Three hundred fifteen vertebrae from C-3 to C-7 in 63 patients were studied. Pedicle dimensions such as pedicle transverse angle (PTA), pedicle sagittal angle (PSA), and pedicle outer width (POW) were measured on axial CT reconstructions, as were linear parameters including the lateral mass thickness (LMT), the anteroposterior (AP) and mediolateral distances between spinal canal and transverse foramen, and spinal canal longitudinal and transverse diameter. In addition, the correlations between PTA and other parameters were calculated using univariate linear regression analysis.

The overall mean LMT ranged from 10.7 to 12.6 mm. The smallest mean AP spinal canal–transverse foramen distance was found at C-7 (1.1 mm),whereas the largest mean distance was at C-4 (3.1 mm). The smallest mean mediolateral spinal canal–transverse foramen distance was found at C-4 (1.2 mm), whereas the largest mean distance was at C-7 (4.7 mm). There were significant intergroup differences between male and female patients except for PTA and spinal canal longitudinal diameter. The PTA had a direct linear correlation with AP and mediolateral spinal canal–transverse foramen distances. The largest Pearson coefficient was 0.71 between the PTA and AP spinal canal–transverse foramen distance and the inverse one was −0.73 between the PTA and mediolateral spinal canal–transverse foramen distance.

Conclusions

Analysis of the data obtained in this study suggests that not only pedicle dimensions but also linear and angular parameters of the VB can be useful data when inserting a CPS.
Delayed occurrence of multiple spinal drop metastases from a posterior fossa choroid plexus papilloma
Authors: Yu Hong , Yao Tom L. , Spooner John , Stumph Jennifer R. , Hester Ray , Konrad Peter E.
Published: January 2008

✓Choroid plexus papilloma is a benign central nervous system tumor that occasionally spreads along the subarachnoid space. The authors report the case of a 49-year-old man who presented with back pain 19 years after resection of a posterior fossa choroid plexus papilloma. Magnetic resonance imaging revealed multiple spinal lesions without any residual or recurrent intracranial tumor. All spinal lesions were resected and histologically diagnosed as atypical choroid plexus papilloma. The authors suggest that patients in whom choroid plexus papilloma is diagnosed should undergo total neuraxis imaging at the time of initial diagnosis as well as periodic follow-up examinations after resection to rule out drop metastases.
Complications of halo fixation in the elderly
Authors: Horn Eric M. , Theodore Nicholas , Feiz-Erfan Iman , Lekovic Gregory P. , Dickman Curtis A. , Sonntag Volker K. H.
Published: January 2008

Object

The risk factors of halo fixation in elderly patients have never been analyzed. The authors therefore retrospectively reviewed data obtained in the treatment of such cases.

Methods

A discharge database was searched for patients 70 years of age or older who had undergone placement of a halo device. In a search of cases managed between April 1999 and February 2005, data pertaining to 53 patients (mean age 79.9 years [range 70–97 years]) met these criteria. Forty-one patients were treated for traumatic injuries. Ten patients had deficits ranging from radiculopathy to quadriparesis, and 43 had no neurological deficit. Adequate follow-up material was available in 42 patients (mean treatment duration 91 days). Halo immobilization was the only treatment in 21 patients, and adjunctive surgical fixation was undertaken in the other 21 patients. There were 31 complications in 22 patients: respiratory distress in four patients, dysphagia in six, and pin-related complications in 10. Eight patients died; in two of these cases, the cause of death was clearly unrelated to the halo brace. The other six patients died of respiratory failure and cardiovascular collapse (perioperative mortality rate 14%). Three patients who died had sustained acute trauma and three had undergone surgical stabilization.

Conclusions

External halo fixation can be used safely to treat cervical instability in elderly patients. The high complication rate in this population may reflect the significant incidence of underlying disease processes.
Biomechanical study on the effect of five different lumbar reconstruction techniques on adjacent-level intradiscal pressure and lamina strain
Authors: Sudo Hideki , Oda Itaru , Abumi Kuniyoshi , Ito Manabu , Kotani Yoshihisa , Minami Akio
Published: January 2008

Object

The objectives of this study were to compare the biomechanical effects of five lumbar reconstruction models on the adjacent segment and to analyze the effects of three factors: construct stiffness, sagittal alignment, and the number of fused segments.

Methods

Nondestructive flexion–extension tests were performed by applying pure moments to 10 calf spinal (L3–S1) specimens. One-segment (L5–6) or two-segment (L5–S1) posterior fusion methods were simulated: 1) one-segment posterolateral fusion (PLF); 2) one-segment PLF with interbody fusion cages (one-segment PLIF/PLF); 3) two-segment PLF; 4) two-segment PLIF/PLF; and 5) two-segment PLF in kyphosis (two-segment kyphotic PLF). The range of motion (ROM) of the reconstructed segments, intradiscal pressure (IDP), and lamina strain in the upper (L4–5) adjacent segment were analyzed.

The ROM was significantly decreased in the PLIF/PLF models compared with that in the PLF alone models after both the one- and two-segment fusions. If the number of fused segments was increased, the pressure and strains were also increased in specimens subjected to the PLIF/PLF procedure, more so than the PLF-alone procedure. In the one-segment PLIF/PLF model the authors observed a reduced IDP and lamina strain compared with those in the kyphotic two-segment PLF model despite the latter’s higher levels of initial stiffness.

Conclusions

If the number of fused levels can be reduced by using PLIF to correct local kyphosis, then this procedure may be valuable for reducing adjacent-segment degenerative changes.
Symptomatic pneumorachis associated with incidental durotomy during microscopic lumbar disc surgery
Authors: Rovlias Aristedis , Pavlakis Emmanuel , Kotsou Serafim
Published: January 2008

✓ Unintended incidental durotomy is not a rare complication of lumbar microsurgery and is usually recognized and treated immediately. The reconstruction process can be complicated further by unpredictable factors. To their knowledge, the authors report the first case of a symptomatic pneumorachis associated with the accidental awakening of a patient during reconstruction of an incidental durotomy following lumbar microdiscectomy.

Incomplete cauda equina syndrome developed in the patient on awakening from surgery after reconstruction of an unintended incidental dural tear that occurred during lumbar microdiscectomy. Symptomatic pneumorachis was revealed on an emergency computed tomography scan, and the patient underwent immediate repeated operation to remove air and decompress the spinal canal.

The increasing number and complexity of surgical procedures in the lumbar spine contribute to the growing incidence of unintended durotomy. The surgeon should be aware of rare complications that may arise. Development of a vacuum phenomenon in conjunction with a ball–valve mechanism may lead to pneumorachis during durotomy repair. If this rare complication is promptly recognized and confronted, the outcome will not be associated with long-term sequelae.
Percutaneous vertebroplasty of a myelomatous compression fracture in the presence of previous posterior instrumentation
Authors: Chakrabarti Indro , Burton Allen W. , Rao Ganesh , Feiz-Erfan Iman , Hlatky Roman , Rhines Laurence D. , Mendel Ehud
Published: January 2008

✓ The authors report the use of percutaneous transpedicular vertebroplasty performed using polymethylmethacrylate (PMMA) in two patients. These men (53 and 57 years old) had previously undergone open surgery and posterior instrumentation to treat myelomatous compression fractures. Both patients presented with acute back pain that manifested after minor activities. Kyphotic wedge fractures were diagnosed at T-11 in one case and at L-1 in the other. Both patients were treated at other hospitals with laminectomy and instrumented fusion; multiple myeloma was diagnosed after surgery. The patients experienced severe, recalcitrant, and progressive pain; on referral, they were found to have persistent kyphosis. Multiple myelomatous lesions of the spine were seen in one case and in the other the L-1 fracture represented the only site of disease. Percutaneous vertebroplasty was performed by injecting PMMA into the anterior third of the compressed vertebral body. Both patients experienced a 50% reduction in pain immediately after treatment; 3 months later both were walking and reported minimal back pain while undergoing treatment for multiple myeloma. Three years after surgery one patient reported no back pain and no progressive instability of the spine. Four years after surgery the other patient remains pain free, ambulatory, and with overall disease remission.

Percutaneous vertebroplasty provided effective analgesia in these two patients with progressive back pain despite posterior stabilization. In both cases, the anterior column was effectively stabilized. A much larger operative intervention with its attendant risks of morbidity was avoided. In addition, subsequent aggressive medical treatment was well tolerated.
Repetitive tensile stress to rat caudal vertebrae inducing cartilage formation in the spinal ligaments: a possible role of mechanical stress in the development of ossification of the spinal ligaments
Authors: Tsukamoto Nobuaki , Maeda Takeshi , Miura Hiromasa , Jingushi Seiya , Hosokawa Akira , Harimaya Katsumi , Higaki Hidehiko , Kurata Kousaku , Iwamoto Yukihide
Published: January 2008

Object

Mechanical stress has been considered one of the important factors in ossification of the spinal ligaments. According to previous clinical and in vitro studies, the accumulation of tensile stress to these ligaments may be responsible for ligament ossification. To elucidate the relationship between such mechanical stress and the development of ossification of the spinal ligaments, the authors established an animal experimental model in which the in vivo response of the spinal ligaments to direct repetitive tensile loading could be observed.

Methods

The caudal vertebrae of adult Wistar rats were studied. After creating a novel stimulating apparatus, cyclic tensile force was loaded to rat caudal spinal ligaments at 10 N in 600 to 1800 cycles per day for up to 2 weeks. The morphological responses were then evaluated histologically and immunohistochemically.

After the loadings, ectopic cartilaginous formations surrounded by proliferating round cells were observed near the insertion of the spinal ligaments. Several areas of the cartilaginous tissue were accompanied by woven bone. Bone morphogenetic protein–2 expression was clearly observed in the cytoplasm of the proliferating round cells. The histological features of the rat spinal ligaments induced by the tensile loadings resembled those of spinal ligament ossification observed in humans.

Conclusions

The findings obtained in the present study strongly suggest that repetitive tensile stress to the spinal ligaments is one of the important causes of ligament ossification in the spine.
Long-term follow up of surgical outcomes in patients with cervical disorders undergoing hemodialysis
Authors: Sudo Hideki , Ito Manabu , Abumi Kuniyoshi , Kotani Yoshihisa , Takeuchi Tatsuto , Yasui Keigo , Minami Akio
Published: January 2008

Object

As increasing numbers of patients receive long-term hemodialysis, the number of reports regarding hemodialysis-related cervical spine disorders has also increased. However, there have been few reports summarizing the surgical results in patients with these disorders. The objective of this study was to evaluate the long-term follow up and clinical results after surgical treatment of cervical disorders in patients undergoing hemodialysis.

Methods

Seventeen patients in whom surgery was performed for cervical spine disorders while they received long-term hemodialysis therapy were enrolled in this study. Of these, 15 underwent follow-up review for more than 3 years after surgery, and these represent the study population. The remaining two patients died of postoperative sepsis. The average follow-up period was 120 months. Five patients without spinal instability underwent spinal cord decompression in which bilateral open-door laminoplasty was performed. Ten patients with destructive spondyloarthropathy (DSA) underwent reconstructive surgery involving pedicle screw (PS) fixation. In eight patients in whom posterior instrumentation was placed, anterior strut bone grafting was performed with autologous iliac bone to treat anterior-column destruction. Marked neurological recovery was obtained in all patients after the initial surgery. In the mobile segments adjacent to the site of previous spinal fusion, the authors observed progressive destructive changes with significant instability in four patients (40%) who underwent circumferential spinal fusion. No patients required a second surgery after laminoplasty for spinal canal stenosis without DSA changes.

Conclusions

Cervical PS-assisted reconstruction provided an excellent fusion rate and good spinal alignment. During the long-term follow-up period, however, some cases required extension of the spinal fusion due to the destructive changes in the adjacent vertebral levels. Guidelines or recommendations to overcome these problems should be produced to further increase the survival rates of patients undergoing hemodialysis.
Giant sacral meningeal diverticula: surgical implications of the “thecal tip” sign
Authors: Feigenbaum Frank , Henderson Fraser C.
Published: January 2008

✓ The surgical anatomy of giant sacral meningeal diverticula varies greatly depending on whether they develop ventral or dorsal to the thecal sac and spinal nerve roots. The ability to distinguish between the two lesion types preoperatively is therefore advantageous. The authors present a method of distinguishing ventral from dorsal meningeal diverticula on magnetic resonance imaging using the “thecal tip sign.” They also describe the differences in operative technique required for resection of each type of diverticular cyst.
Microscopic bilateral decompression through unilateral laminotomy for lumbar canal stenosis in patients undergoing hemodialysis
Authors: Sasaki Manabu , Abekura Makoto , Morris Shayne , Akiyama Chihiro , Kaise Kazuya , Yuguchi Takamichi , Mori Shintaro , Iwatsuki Koichi , Yoshimine Toshiki
Published: January 2008

Object

Microscopic bilateral decompression through a unilateral laminotomy (MBDUL) is a minimally invasive technique used to treat lumbar canal stenosis (LCS). In the present study, MBDUL was performed to treat LCS in eight patients undergoing hemodialysis.

Methods

Surgical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) scale (highest possible score 29). The JOA scale was administered preoperatively, at 1 month and 3 months postoperatively, and at the final follow-up examination. One patient refused to undergo the postoperative assessment after the 1-month examination; the mean follow-up duration of the remaining seven patients was 24 months (range 18–31 months). The mean age at the time of surgery was 62 years (range 48–76 years), and the mean duration of hemodialysis therapy was 21.4 years (range 3–28 years). All patients could walk within 2 days of surgery. The mean angle of the straight leg–raising (SLR) test was 53.8° preoperatively, and this increased to 69.4° postoperatively. Six patients felt enhancement of sciatica or leg pain when performing the SLR test preoperatively, a finding that was absent postoperatively at least until the final follow-up examination. The mean preoperative JOA score was 11.6 (range 4–22), and the score markedly improved to 19.8 (range 15–23) at 1 month and 20.6 (range 16–25) at 3 months. The mean JOA score decreased to 17.1 (range 12–25) at the final follow-up examination, but this decrease was attributed to other physical disorders.

Conclusions

The authors conclude that MBDUL is a safe and effective surgical treatment for patients undergoing hemodialysis who are suffering from LCS.
An evaluation of vascular anatomy for minilaparotomic anterior L4–5 procedures
Authors: Kang Byung-Uk , Lee Sang-Ho , Jeon Sang-Hyeop , Park Jong Dae , Maeng Dae Hyeon , Choi Young Geun , Tsang Yi-Sheng
Published: January 2008

Object

The complexity of the vascular anatomy pertinent to the L4–5 intervertebral disc space has led to difficulties when performing the anterior approach to the lumbar spine. The purpose of the present study was to evaluate the variations of the great vessels to match the imaging-documented axial anatomy with the surgical exposure.

Methods

The authors analyzed data obtained in 223 patients who had undergone mini–open anterior lumbar surgery involving the L4–5 disc. The preoperative magnetic resonance images or computed tomography scans were evaluated by examiners blinded to the surgical approach to determine the vascular configuration. All complications of the procedures were described.

Two major variations of the vascular configuration were delineated according to the location of the bifurcation of the inferior vena cava. On images showing the lower margin of the L-4 vertebra, the anatomy in 182 patients (81%) was classified as Type A because the inferior vena cava (IVC) was not bifurcated; in 38 patients (17%) it was classified as Type B because the IVC was bifurcated. Type A could be subdivided into Types A1 and A2 according to whether the aorta was bifurcated (A2) or not (A1) on the same image. The surgical exposure used was above the bifurcations (in Type A) and below the bifurcations (in Type B). The major complications were three venous injuries, and the leading complication was sympathetic dysfunction in 14 patients, which in most cases resolved spontaneously.

Conclusions

Careful preoperative evaluation of the vascular anatomy is essential to conducting successful anterior lumbar surgery. The determination of an appropriate approach can contribute to a reduction of unnecessary vascular retraction and a consequent decrease in vascular complications.
Flexion myelopathy of the thoracic spine
Authors: Fujibayashi Shunsuke , Neo Masashi , Nakamura Takashi
Published: January 2008

✓The authors report a rare case of surgically treated symptomatic thoracic kyphosis caused by dynamic compression in an elderly man. Myelopathy due to thoracic kyphosis has been reported in patients with congenital kyphosis, Scheuermann dorsal kyphosis, and Cushing disease, but to the authors’ knowledge this is the first report of dynamic kyphosis in an elderly person. This otherwise healthy 84-year-old man presented with a 2-year history of progressive difficulty in walking and bilateral leg dysesthesia. Despite several cervical and lumbar surgeries, his symptoms gradually worsened. A radiological examination revealed severe thoracic kyphosis, with a lateral Cobb angle of 59° from T-2 to T-12. On a dynamic computed tomography (CT) myelogram, severe thoracic spinal cord draping and stretching on flexion was demonstrated. On extension, however, imaging studies failed to show draping or stretching. Posterior corrective fusion was performed with instrumentation from T-2 to T-9. Postoperative CT myelography demonstrated no significant spinal cord compression with restoration of the cerebrospinal fluid space anterior to the spinal cord, and the successful correction of the kyphosis to 44°. The patient’s neurological sequelae gradually resolved throughout 6 months of follow up.
Ossification of Ligamentum
Authors: Wang Wenbao , Kong Linghua
Published: January 2008

Object

The authors evaluated different surgical methods used to treat thoracic ossification of the ligamentum flavum (OLF).

Methods

Data obtained in 40 patients who underwent posterior decompression for thoracic myelopathy caused by thoracic OLF were studied retrospectively. There were 32 men and eight women. All patients underwent posterior decompression in which laminoplasty was performed or laminectomy combined with lateral fusion. Every surgical specimen was stained with H & E, and scanning electron microscopy was performed in 20 cases. The mean follow-up period was 28 months. Postoperative outcomes were evaluated using a recovery scale based on the Japanese Orthopaedic Association classification. There were a total of 168 ossified segments in this series, 77.4% of which were located in the lower thoracic spine. Marginal osteophyte formation was found in 36 patients; in 32 of the 36 patients, these marginal osteophytes were located at the intervertebral space either higher or lower than the ossified segment. Scanning electron microscopy showed elastic fiber breakdown, proliferation of collagenous fibers, calcification, and OLF in the same microscopy region. Laminoplasty was performed in four patients. In three cases surgery resulted in unchanged or worse outcome (increased kyphotic deformity in two), and in one it resulted in good outcome. Laminectomy combined with lateral fusion was performed in 36 patients, in 30 cases of which it resulted in a good or fair outcome, and increased kyphotic deformity in only one. Of these 36 laminectomy-treated patients, an en bloc laminectomy-treated procedure was performed in 16 patients; in 11 of the 12 patients with lateral or diffuse-type lesions the surgery resulted in a good or fair outcome. En bloc laminectomy, however, seems ineffective in the treatment of patients with thickened, nodular-type thoracic OLF, as the procedure resulted in worse outcome in two of the four patients. The authors have thus developed a new modality of laminectomy that they have termed “separating laminectomy,” which they performed in 16 patients with thickened, nodular-type OLF; in 13 cases it resulted in a good or fair outcome, and in only one case did it result in a worse outcome.

Conclusions

The pathogenesis of thoracic OLF is mainly due to the localized mechanical stress on the ligament. Laminectomy combined with lateral fusion is the treatment of choice for thoracic OLF; furthermore, in terms of the configuration of the ossified lesion, en bloc laminectomy is suitable for the treatment of lateral-type and diffuse-type OLF, and the separating laminectomy is suitable for the thickened, nodular-type OLF.
Nonoperative Treatment
Authors: Natelson Stephen E.
Published: January 2008

Object

Despite extensive published research on thoracolumbar burst fractures, controversy still surrounds which is the most appropriate treatment. The objective of this study was to evaluate the scientific literature on operative and nonoperative treatment of patients with thoracolumbar burst fractures and no neurological deficit.

Methods

In their search of the literature, the authors identified all possible relevant studies concerning thoracolumbar burst fracture without neurological deficit. Two independent observers performed study selection, methodological quality assessment, and data extraction in a blinded and objective manner for all papers identified during the search. In a synthesis of the literature, the authors obtained evidence for both operative and nonoperative treatments.

Conclusions

There is a lack of evidence demonstrating the superiority of one approach over the other as measured using generic and disease-specific health-related quality of life scales. There is no scientific evidence linking posttraumatic kyphosis to clinical outcomes. The authors found that there is a strong need for improved clinical research methodology to be applied to this patient population.
Diagnosis and treatment of multiple hydatid cysts at the craniovertebral junction
Authors: Lath Rahul , Ratnam Boola Gnana , Ranjan Alok
Published: January 2008

✓Echinococcosis, or hydatid disease, of the craniovertebral junction and skull base is rare. The authors report the occurrence of multiple hydatid cysts at this anatomical location in a young woman who was previously misdiagnosed with tuberculosis. The patient underwent transoral excision of the hydatid cysts followed by posterior decompression and occipitocervical fusion. She was treated postoperatively with albendazole for 12 weeks with a good outcome. The management of spinal hydatid disease is reviewed.
Clinical and radiographic analysis of cervical disc arthroplasty compared with allograft fusion: a randomized controlled clinical trial
Authors: Mummaneni Praveen V. , Burkus J. Kenneth , Haid Regis W. , Traynelis Vincent C. , Zdeblick Thomas A.
Published: January 2008

Object

The authors report the results of a prospective randomized multicenter study in which the results of cervical disc arthroplasty were compared with anterior cervical discectomy and fusion (ACDF) in patients treated for symptomatic single-level cervical degenerative disc disease (DDD).

Methods

Five hundred forty-one patients with single-level cervical DDD and radiculopathy were enrolled at 32 sites and randomly assigned to one of two treatment groups: 276 patients in the investigational group underwent anterior cervical discectomy and decompression and arthroplasty with the PRESTIGE ST Cervical Disc System (Medtronic Sofamor Danek); 265 patients in the control group underwent decompressive ACDF. Eighty percent of the arthroplasty-treated patients (223 of 276) and 75% of the control patients (198 of 265) completed clinical and radiographic follow-up examinations at routine intervals for 2 years after surgery.

Analysis of all currently available postoperative 12- and 24-month data indicated a two-point greater improvement in the neck disability index score in the investigational group than the control group. The arthroplasty group also had a statistically significant higher rate of neurological success (p = 0.005) as well as a lower rate of secondary revision surgeries (p = 0.0277) and supplemental fixation (p = 0.0031). The mean improvement in the 36-Item Short Form Health Survey Physical Component Summary scores was greater in the investigational group at 12 and 24 months, as was relief of neck pain. The patients in the investigational group returned to work 16 days sooner than those in the control group, and the rate of adjacent-segment reoperation was significantly lower in the investigational group as well (p = 0.0492, log-rank test). The cervical disc implant maintained segmental sagittal angular motion averaging more than 7°. In the investigational group, there were no cases of implant failure or migration.

Conclusions

The PRESTIGE ST Cervical Disc System maintained physiological segmental motion at 24 months after implantation and was associated with improved neurological success, improved clinical outcomes, and a reduced rate of secondary surgeries compared with ACDF.
Augmentation of an anterior lumbar interbody fusion with an anterior plate or pedicle screw fixation: a comparative biomechanical in vitro study
Authors: Nichols Tann A. , Yantzer Brenda K. , Alameda Suzanne , Johnson Wesley M. , Guiot Bernard H.
Published: January 2008

Object

Posterior pedicle screw (PS) instrumentation is often used to augment anterior lumbar interbody fusion (ALIF) but at the cost of an increase in the morbidity rate due to the second approach and screw placement. If anterior plates were found to be biomechanically equivalent to PS fixation (PSF) after ALIF, then this second approach could be avoided without decreasing vertebral stability.

Methods

Eight cadaveric L5–S1 spinal segments were tested under four conditions: intact, following anterior discectomy and interbody spacer placement, after placement of an anterior plate, and following PSF. The elastic zone and stiffness were calculated for axial compression, flexion/extension, lateral bending, and torsion.

Neither anterior plate stabilization nor PSF showed significant intergroup differences in stiffness or the elastic zone. Both exhibited greater stiffness in flexion than the intact specimens (p < 0.001). Pedicle screw fixation was associated with a decreased elastic zone in lateral bending compared with the intact specimen (p < 0.04).

Conclusions

Anterior plate fixation is biomechanically similar to PSF following ALIF. Surgeons may wish to use anterior plates in place of PSs to avoid the need for a posterior procedure. This may lead to a decrease in operative morbidity and improved overall outcomes.
Open kyphoplasty for management of metastatic and severe osteoporotic spinal fracture
Authors: Fuentes Stéphane , Métellus Phillipe , Pech-Gourg Grégoire , Adetchessi Tarek , Dufour Henri , Grisoli François
Published: January 2008

Object

Elderly patients in poor general health frequently suffer vertebral body (VB) fractures due to osteoporosis or vertebral metastatic lesions. Kyphoplasty and vertebroplasty have become the standard treatment for these types of fractures. In certain conditions that cause local kyphosis, such as spinal cord compression due to a metastatic epidural tumor or the shortening of the spinal canal secondary to vertebral compression, the surgical treatment should provide decompression and stabilization during a short intervention. In this study the authors evaluated a surgical technique that frequently combines a same-session surgical decompression, such as a laminectomy, and posterior instrumentation-assisted stabilization during the same open intervention in which the VB is stabilized by kyphoplasty.

Methods

During an 18-month period, the authors treated 18 patients with VB fractures according to this protocol: 14 patients with vertebral metastatic lesions and four with osteoporosis. The patients' mean age was 60 years. All suffered severe pain preoperatively (mean visual analog scale [VAS] score of 7). Fourteen of the 18 patients suffered a neurological deficit. Twenty-three vertebral levels were treated; in 15 patients it was necessary to place posterior instrumentation. The mean duration of the intervention was 90 minutes.

Pain in all patients improved 3 days after the intervention, and the mean VAS score decreased to 2. Patients with a neurological dysfunction improved. The mean quantity of injected cement for the kyphoplasty procedure was 7 ml. The mean duration of hospitalization was 7 days. Neuroimaging revealed cement leaks in two cases: one into the disc interspace and one anteriorly into the fractured part of the vertebra. After the intervention, most patients with metastatic lesions underwent radiotherapy. No procedure-related complications occurred.

Conclusions

This procedure allows decompression of the spinal cord, consolidation of the VB and thus a stabilization of the vertebral column, and may provide an alternative treatment to invasive VB excision in patients in poor general health.
Surgical management of chordomas of the cervical spine
Authors: Barrenechea Ignacio J. , Perin Noel I. , Triana Aymara , Lesser Jonathan , Costantino Peter , Sen Chandranath
Published: January 2008

Object

Chordomas of the cervical spine are rare tumors. Although en bloc resection has proven to be the ideal procedure in other areas, there is controversy regarding this approach in the cervical spine. The goal in this study was to determine whether piecemeal tumor resection was efficient in the management of chordomas that arise in this location.

Methods

The authors retrospectively reviewed all 74 cases of chordoma treated by their group. Seven patients with isolated cervical chordomas who were treated between October 1992 and January 2006 were identified. There were four male and three female patients, whose ages ranged from 6 to 61 years (mean 34.4 years). Follow-up duration ranged from 7 to 169 months (median 23 months). All cases were managed using a retrocarotid approach with mobilization of the vertebral artery. When the tumor could not be completely resected via the initial anterior approach, a subsequent posterior resection was performed. Tumor resection was intralesional in all cases, and gross-total tumor resection was achieved in six cases. One patient required a second resection 4 months later. In all cases, a posterior stabilization procedure was performed. Five patients underwent anterior fusion (three with fibular allograft and two with iliac crest), whereas two underwent occipitocervical fusion. In two patients with dedifferentiated chordoma metastasis developed, and one of them died 7 months later. The other patient with metastasis died suddenly at home 26 months postsurgery, presumably from aspiration. At the time of this submission, there were no signs of recurrence in five patients.

Conclusions

The authors believe that, in most cases, en bloc resection of cervical chordoma is not feasible. This is due to the tendency of chordomas to involve multiple compartments at the time of diagnosis. In the authors' experience, intralesional radical resection remains an effective surgical approach to this disease entity.
'Loved to Death': Coral Collecting in the Great Barrier Reef, Australia, 1770-1970
Authors: Daley Ben , Griggs Peter
Published: January 2008

Recent scholarship has investigated the rate of deterioration of the Great Barrier Reef of Australia since European settlement and the severity of human impacts on that ecosystem. Yet in previous environmental histories of the Great Barrier Reef, the impacts of coral collecting have not been adequately documented. Using documentary and oral history sources, a reconstruction of historical coral collecting is possible; analysis of those sources indicates that the extent, duration and intensity of coral collecting led to profound transformations of some coral reefs, with particular degradation at Double, Green, Heron, Masthead and Lady Musgrave Islands, and at Wistari Reef. That degradation was due to the combined impacts of prolonged, cumulative coral souveniring by tourists and to the removal of large amounts of material by commercial collectors. Although coral collecting has been restricted since 1933, both licensed and unlicensed collecting continued after that year. Extensive documentary evidence indicates that coral collecting was accompanied by the deterioration of coral reefs; those documentary accounts are supported by oral history evidence. Evaluation of the precise impacts of coral collectors in the Great Barrier Reef requires further scientific research and monitoring, although comparison with other coral reef ecosystems suggests that those impacts are likely to have been severe.
The Mammalian Rod Cell Photoreceptor Rhodopsin
Authors: Abdulaev Najmoutin G. , Ridge Kevin D.
Published: January 2008

Originally published in: Handbook of Photosensory Receptors. Edited by Winslow R. Briggs and John L. Spudich. Copyright © 2005 Wiley‐VCH Verlag GmbH & Co. KGaA Weinheim. Print ISBN: 3‐527‐31019‐7

The sections in this article are

Introduction

Rhodopsin and Mammalian Visual Phototransduction

Signal Amplification by Light‐activated Rhodopsin

Inactivation of Light‐activated Rhodopsin

Properties of Rhodopsin

Isolation of Rhodopsin

Biochemical and Physicochemical Properties of Rhodopsin

Post‐translational Modifications in Rhodopsin

Membrane Topology of Rhodopsin and Functional Domains

Transmembrane Domain of Rhodopsin

Intradiscal Domain of Rhodopsin

Cytoplasmic Domain of Rhodopsin

Chromophore Binding Pocket and Photolysis of Rhodopsin

Structure of Rhodopsin

Crystal Structure of Rhodopsin

Atomic Force Microscopy of Rhodopsin in the Disk Membrane

Activation Mechanism of Rhodopsin

Conclusions

Acknowledgements