Showing papers in "Spine in 1991"

A prospective study of work perceptions and psychosocial factors affecting the report of back injury.

Abstract: A longitudinal, prospective study was conducted on 3,020 aircraft employees to identify risk factors for reporting acute back pain at work. The premorbid data included individual physical, psychosocial, and workplace factors. During slightly more than 4 years of follow-up, 279 subjects reported back problems. Other than a history of current or recent back problems, the factors found to be most predictive of subsequent reports in a multivariate model were work perceptions and certain psychosocial responses identified on the Minnesota Multiphasic Personality Inventory (MMPI). Subjects who stated that they "hardly ever" enjoyed their job tasks were 2.5 times more likely to report a back injury (P = 0.0001) than subjects who "almost always" enjoyed their job tasks. The quintile of subjects scoring highest on Scale-3 (Hy) of the MMPI were 2.0 times more likely to report a back injury (P = 0.0001) than subjects with the lowest scores. The multivariate model, including job task enjoyment, MMPI Scale-3, and history of back treatment, revealed that subjects in the highest risk group had 3.3 times the number of reports in the lowest risk group. These findings emphasize the importance of adopting a broader approach to the multifaceted problem of back complaints in industry and help explain why past prevention efforts focusing on purely physical factors have been unsuccessful.

Prevalence of back pain in pregnancy.

Abstract: The prevalence of back pain was studied in 855 pregnant women who were followed from the 12th week of pregnancy, every 2nd week, until childbirth. The 9-month period prevalence was 49%, with a point prevalence of 22-28% from the 12th week until delivery. Because 22% of the women had back pain at the

Cervical human vertebrae. Quantitative three-dimensional anatomy of the middle and lower regions.

Abstract: In this study, the three-dimensional quantitative anatomy of middle and lower cervical vertebrae was determined. The three-dimensional coordinates of various marked points on the surface of the vertebra were measured with a specially designed morphometer instrument. From these coordinates, linear dimensions, angulations, and areas of surfaces and cross-sections of most vertebral components were calculated. The results showed two distinct transition regions: 1) toward the thoracic spine by the wider C7 vertebra but narrower spinal canal; and 2) toward the upper cervical region with the larger pedicle and spinous process of C2. Based on the study of 72 human cervical vertebrae, mean and standard error of the mean values of some clinically important dimensions of vertebral body, spinal canal, pedicles, transverse processes, spinous process, and uncovertebral joints are given for C2-C7 vertebrae. The areas of the end plates, spinal canal, and pedicles were modeled by elliptical and triangular shapes, and results were compared with the actual measurements.

Stimulation of mature canine intervertebral disc by growth factors.

Abstract: Although the role of growth factors in the regulation of phenotype, maintenance, and repair of cartilaginous tissues has been extensively evaluated, the response of intervertebral disc to growth factors has not been investigated. A tissue culture system for annular, transitional, and nuclear regions of mature canine intervertebral disc was devised to assess the proliferative response, as determined by 3H-thymidine incorporation, and the biosynthetic response, assayed by 35S-sulfate incorporation into proteoglycan, of these tissues to growth factors. The culture system achieved steady-state conditions in serum-free mediums at 4 days and was perturbed by plasma-derived equine serum, fetal calf serum, insulin-like growth factor-1, epidermal growth factor, fibroblast growth factor, and transforming growth factor-beta. Incorporation rates by the tissue regions of up to five times the control rate were recorded; the nucleus and transition zone responded more than anulus. Transforming growth factor-beta and epidermal growth factor elicited greater responses than fibroblast growth factor; insulin-like growth factor-1 produced a marginally significant response in the nucleus and no response in the anulus and transition. The intervertebral disc appeared to respond to the growth factors differently than cartilage, and this may represent inherent differences in cell biology. The biologic significance and basis of these responses require further evaluation. However, the responses observed, particularly in the nucleus and transition zone suggest the possibility that disc repair can be modulated by growth factors. A therapeutic approach to degenerative disc disease involving enhanced tissue repair by exogenous growth factors would be of great clinical significance.

Thoracic human vertebrae. Quantitative three-dimensional anatomy.

Abstract: This study details the quantitative three-dimensional surface anatomy of thoracic vertebrae based on a study of 144 vertebrae. The thoracic spine was found to have three distinct regions: upper, middle, and lower segments. The two end segments appear to be transitional zones toward cervical and lumbar regions. The middle zone (T3 to T9) is of utmost importance due to the presence of the combination of narrow spinal canal and critical vascular supply. Means and standard errors of the means for linear, angular, and area dimensions of vertebral bodies, spinal canal, pedicle, pars articularis, spinous and transverse processes, and rib articulations are provided for all thoracic vertebrae. This information is necessary for constructing accurate mathematical models of the human spine. It will also provide a better understanding of the spine, and allow for a more precise clinical and surgical management of spinal problems.

Change of disc height, radial disc bulge, and intradiscal pressure from discectomy. An in vitro investigation on human lumbar discs.

Abstract: Partial discectomy was done in vitro on 15 human lumbar discs from donors 20-40 years of age. The change of disc height, radial disc bulge, and intradiscal pressure was measured in relation to the mass of central disc tissue excised. Disc height decreases and radial disc bulge increases approximately in proportion with the mass of the tissue excised. At the same time, intradiscal pressure decreases. On average, removal of 1 g of disc tissue results in a height decrease of 0.8 mm and a radial bulge increase of 0.2 mm. Removal of 3 g of central disc tissue lowers the intradiscal pressure to approximately 40% of its initial value. A mechanical model is presented which explains the observed relation between the volume of material removed and the subsequent change of height, bulge, and pressure. The experimental results and the model provide insight into the rationale of disc pressurization. A high intradiscal pressure is a prerequisite for the mechanical function of the disc under physiologic conditions.

An experimental study on transpedicular screw fixation in relation to osteoporosis of the lumbar spine.

Abstract: In order to elucidate the relationship between the severity of osteoporosis and the fixation strength of a pedicle screw, screw pull-out tests were performed using cadaveric lumbar vertebrae. The severity of osteoporosis was evaluated by the Jikei osteoporosis grading scale (Jikei method), bone mine

The use of freeze-dried allograft bone for anterior cervical fusions

Abstract: A consecutive series of 87 patients undergoing Smith-Robinson anterior cervical fusion were analyzed. Either freeze-dried tricortical iliac crest bone or tricortical autograft bone was used. Surgical technique was otherwise identical. Radiography showed delayed union at 3 months in 13% of patients with autograft and in 37% of patients with freeze-dried allograft. At 1 year, radiography showed nonunion in 8% of patients with autograft and in 22% of patients with allograft. One-level procedures had a delayed union rate of 7% for autograft and 21% for allograft. Nonunion in one-level procedures was 5% for both autograft and allograft. For two-level procedures, the nonunion rate was 17% for autograft and 63% for allograft. Graft collapse was more commonly seen with freeze-dried allograft (30%) than with autograft (5%). Relief of neck and arm pain, however, was similar in both groups.

1991 Volvo Award in clinical sciences. Smoking and lumbar intervertebral disc degeneration: an MRI study of identical twins.

Abstract: The primary objective of this study was to determine whether disc degeneration, as assessed through magnetic resonance imaging, is greater in smokers than in nonsmokers. To control for the maximum number of potentially confounding variables, pairs of identical twins highly discordant for cigarette s

Anatomic considerations for plate-screw fixation of the cervical spine.

Abstract: A cadaveric study was done to investigate the variability of interfacet distances from C3 to C7, to learn pedicle morphology at C7-T2, and to determine potential dangers of plate-screw osteosynthesis technique of the cervical spine. Twenty-two cadavers were dissected from C2 to C7 to expose the lateral masses and nerve roots. The interfacet distances from the center of the lateral mass to the next lateral mass from C3 to C7 vary widely among different individuals, ranging from 9 mm to 16 (average, 13 mm). A new plate design is necessary to better accommodate the differences in interfacet distances among different patients and different levels. The second part of the study involved 11 dissected cadaveric specimens of the cervicothoracic junction. The pedicle entry point was 1 mm inferior to the midportion of the facet joint for C7, T1, and T2. The medial angulation averaged 34 degrees at C7, 31.8 degrees at T1, and 26.5 degrees at T2. The mediolateral and superoinferior outer pedicle diameters were 6.9 mm and 7.5 mm at C7, 8.5 mm and 9.5 mm at T1, and 7.5 mm and 10.7 mm at T2, respectively. The mediolateral inner diameter averaged 5.18 mm, 6.4 mm, 5.5 mm for C7, T1 and T2, respectively. The pedicle distances (from the entry point to the posterior vertebral body line) measured 9.1 mm, 9.9 mm, and 10.4 mm for respective levels. The margins for error are small when using pedicle screws at these levels. If a pedicle screw must be used at C7, T1, and T2, one must have precise knowledge of the entrance point, diameters, and 25-30 degrees medial direction.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional Radiographic Diagnosis of the Lumbar Spine: Flexion—Extension and Lateral Bending

Abstract: Several attempts have been made to measure the segmental range of motion in the lumbar spine during flexion-extension with the purpose of gathering additional data for the diagnosis of instability. The previous studies were performed in vitro or in vivo during active motion. The aim of this study was to obtain normal values of passively performed segmental motions. Forty-one healthy adults were examined by means of functional radiographs during flexion-extension and lateral bending. A graphic construction method and a computer-assisted method were used to measure rotations. Comparing with recent in vivo studies, the values obtained for normal angles of rotation were predominately larger. This might be due to the passive examination used in the study. The graphic construction method and computer-assisted method techniques are equally reliable, but the computer-assisted method method yields other important kinematic data, such as translations. It is proposed that passive motion be applied during functional examination of patients with suspected instabilities. However, the large variation of rotational values between individuals in the normal population may limit the clinical usefulness of functional lumbar analysis using this parameter. Future studies should explore the clinical relevance of determining altered segmental mobility in low-back pain patients.

A controlled study of caudal epidural injections of triamcinolone plus procaine for the management of intractable sciatica.

Abstract: The management of sciatica due to lumbar nerve root compromise remains controversial, probably because few well-controlled studies of conservative management have been performed. This preliminary study assesses the efficacy of epidural injections of 80 mg triamcinolone acetonide plus 0.5% procaine hydrochloride in saline, administered via the caudal route, in a double-blind, placebo controlled trial with 1 year follow-up. Twenty-three patients were entered into the study: 12 received treatment and 11 placebo. The active group showed significant pain relief (P = 0.02) and a significant increase in mobility (P = 0.01) at 4 weeks, which resulted in improved quality of life (P = 0.02). At 1 year, subjective and objective measures improved in both groups. The improvement was greater in the actively treated group, but only the objective assessment (straight leg raise) was statistically significant.

Determinants of sciatica and low-back pain.

Abstract: Several factors were studied for their association with the prevalence of chronic low-back syndromes, sciatica, and unspecified low-back pain (LBP) in 2,946 women and 2,727 men (age range, 30–64 years) participating in the Mini-Finland Health Survey, a project aimed at comprehensive evaluation of th

Variations in balance and body sway in middle-aged adults. Subjects with healthy backs compared with subjects with low-back dysfunction.

Abstract: In a preliminary investigation of 45 middle aged adult subjects, 20 with low-back pain (LBP) and 25 with healthy backs (HB), balance responses (body sway) were measured under different sensory conditions with computerized force plate stabilometry. Compared with HB subjects, in the most stable and then the least stable balance positions, the LBP subjects demonstrated significantly greater postural sway, kept their center of force (COF) significantly more posterior, and were significantly less likely to be able to balance on one foot with eyes closed. Based on subjective observations, the LBP subjects were more likely to fulcrum about the hip and back to maintain uprightness in challenging balance tasks compared with healthy controls who maintained their fulcrum for the COF around the ankle. Research is needed to determine the incidence of balance problems in LBP patients compared with controls. Effective physical therapy assessment and treatment of LBP patients may require attention to postural alignment, strength, flexibility, joint stability, balance reactions, and postural strategies.

The intersegmental and multisegmental muscles of the lumbar spine. A biomechanical model comparing lateral stabilizing potential.

Abstract: The intersegmental and multisegmental musculature of the lumbar spine was studied in a biomechanical model to compare their lateral stabilizing potential By approximating the active and passive behavior of the stretch reflex as a variable stiffness spring whose stiffness was proportional to activation, the critical muscle stiffness required for mechanical stability was calculated The model demonstrated that the intersegmental muscles were the least efficient at laterally stabilizing the spine At any given load, multisegmental muscles were more efficient, and their efficiency increased with the number of segments spanned The most efficient muscles were those that originated from the pelvis, spanning the maximum number of segments The muscular model was unstable, regardless of the muscular stiffness, when any vertebral segment was devoid of muscle Moreover, when the load on the spine is increased, buckling can be prevented most efficiently with the pelvic muscles and least efficiently with the intersegmental muscles

Posterior cervical arthrodesis with AO reconstruction plates and bone graft.

Abstract: The efficacy of posterior arthrodesis of the cervical spine with AO reconstruction plates and autogenous bone graft was evaluated in a prospective study. The technique of surgical exposure and the application of the reconstruction plates fixed with screws to the lateral masses is described in detail. Of 30 patients with unstable cervical spines, all had solid fusions based on flexion and extension radiographs at follow-up averaging 17.8 months. No patient's neurologic function deteriorated. All incomplete spinal cord injuries improved at least one Frankel level. There were no neurologic or vascular complications. At follow-up, three patients had fusions extending one level longer than those instrumented. Three other patients had an increase in kyphosis compared with the operative reduction, which was not clinically significant. Although a single screw loosened in three other patients, none had an increased deformity, and all progressed to successful arthrodesis. This technique is particularly advantageous when spinous processes, laminas, and facets are injured or deficient, or when facet-type fusions are indicated.

Importance of bone mineral density in instrumented spine fusions.

Abstract: The effect of equivalent mineral density on pedicular screw fixation strength was investigated. The equivalent mineral density of human vertebral bodies was correlated highly with the pullout force of Kluger screws (r2 = 0.61, P less than 0.02). A moderate to high correlation existed between density and vertical force (r2 = 0.42 for Kluger screws, r2 = 0.55 for Steffee screws, P less than 0.02). In calf vertebral bodies of higher density (146 +/- 14 mg/cc), the forces were significantly higher than in the human vertebral bodies (P less than 0.05). Human lumbosacral spines were instrumented with three different fixators: Steffee plates, AO fixateur interne, and Kluger fixateur interne. Of five specimens with a mean density of 88 +/- 11 mg/cc, one screw loosened. More than one screw loosened in six specimens with a mean density of 63 +/- 12 mg/cc, and no screw loosened in four specimens with a mean density of 114 +/- 38 mg/cc. Measurement of equivalent mineral density correlates with the fixation strength of the intrapedicular screws in vitro and should be considered in patients with signs of osteopenia before using pedicular screws for spinal fusions. It is also concluded that calf spines are a good model for testing implants because they tend to focus failure processes in the implant rather than in the implant-bone interface.

Neurologic complications of surgery for cervical compression myelopathy.

Abstract: Neurologic complications resulting from surgery for 384 cases of cervical myelopathy (cervical soft disc herniation, spondylosis, ossification of the posterior longitudinal ligament) were reviewed. Surgical procedures performed included 134 anterior interbody fusions (Cloward or Robinson-Smith technique), 70 subtotal corpectomies with strut bone graft, 85 laminectomies, and 95 laminoplasties. Twenty-one patients (5.5%) sustained neurologic deterioration related to surgery. The deterioration was classified into two types on the basis of the neurologic signs observed: deterioration of spinal cord function or of nerve root function. Manifestations of the former varied from weakness of the hand to tetraparesis. Paralysis of the deltoid and biceps brachii muscles was an exclusive feature of deterioration in the nerve root group. Causes of this paralysis included malalignment of the spine related to graft complications, and a tethering effect on the nerve root following major shifting of the spinal cord after decompression. The causes of deterioration of the cord function included spinal cord injury during surgery, malalignment of the spine associated with graft complication, and epidural hematoma.

Spinal cord injuries. Clinical, functional, and emotional status.

Abstract: Ninety-eight patients with traumatic spinal cord injury, at a median age of 33.5 years (range, 16-72 years), with nonremarkable distributions of neurologic characteristics were investigated at a median of 2.3 years (range, 0.1-23 years) after injury. Functioning, mood disturbances, and overall quality of life were recorded with established self-assessment instruments. Physical dysfunction levels were moderate, being proportionate to neurologic impairment. Psychosocial functions, mood states, and quality-of-life perceptions did not differ from those of a control population sample. Psychosocial function and mood disturbances varied greatly during the first 4 years after injury, but patients' later recordings expressed predominantly a balanced emotional state and a rewarding social life. Progress in this direction consisted of clearly lessened physical dysfunction 1 year after injury and better psychosocial function and well-being after 2 years, whereas patterns of social activities and contacts became gradually less inhibited during a 4-year period after injury. Analysis of complications in patients' histories that affected function and mood showed severe pain to be the only complication that related to lower quality-of-life scores. Urinary incontinence and infection and autonomous dysreflexia related to inhibited self-care performance; spasticity related to impaired ambulation and feeding skills. Gainful employment was the only demographic factor linked to high quality-of-life scores.

Correlation of radiologic assessment of lumbar spine fusions with surgical exploration.

Abstract: Although inspection of posterolateral lumbar fusion is the best method of determining its solidity, routine exploration of the fusion is somewhat impractical because of the morbidity and expense involved. Removal of internal fixation devices or implantable batteries or reoperation for failed back surgery enabled the exploration and assessment of lumbar spine fusions in 214 operations on 175 patients. The preoperative radiologic assessment (plain roentgenographs, polytomography, bending films, and computed tomographic scans) were correlated with surgical findings. This study indicated a significant percentage of inaccuracy of all radiologic modalities used. Noncorrelations were present in 36% of plain roentgenographs, 41% of polytomograms, 38% of bending films, and 43% of computed tomographic scans. Radiologic inaccuracy was manifest on both the positive and negative sides. Computed tomographic scanning presented the lowest percentage of inaccuracy (22%) and bending films the highest percentage (27%). Based on these findings, there exists the need for more accurate noninvasive methods to determine the solidity of spine fusions.

Disc degeneration and associated abnormalities of the spine in elite gymnasts. A magnetic resonance imaging study.

Abstract: The thoracolumbar spine was examined by magnetic resonance imaging (MRI) and the history of back pain was analyzed in 24 male elite gymnasts (age range, 19-29 years) and in 16 male nonathletes (age range, 23-36 years). Disc degeneration, defined as reduced disc signal intensity, was significantly more common in athletes (75%) than in nonathletes (31%). The gymnasts also had a higher incidence of other abnormalities of the thoracolumbar spine, and there was a significant correlation between reduced disc signal intensity and the other abnormalities among the gymnasts. There were also significant correlations between back pain and reduced disc signal intensity and abnormal vertebral configuration when the gymnasts run a high risk of developing severe abnormalities of the thoracolumbar spine, and they often have a history of back pain.

Spinal cord monitoring. Results of the Scoliosis Research Society and the European Spinal Deformity Society survey.

Abstract: The Scoliosis Research Society (SRS) and the European Spinal Deformity Society (ESDS) membership was surveyed regarding the use of intraoperative monitoring of somatosensory evoked potentials in spinal surgery. A total of 242 people responded, with 188 using intraoperative monitoring. A second survey was distributed detailing the technical aspects of monitoring, of which 71 were returned. A total of 342 neurologic deficits were reported to have occurred with monitoring in place. Two hundred forty-six (72%) were accurately detected, and 96 (28%) were not detected by sensory cord evoked potentials (SCEP). There were 1,003 false-positive cases reported. The incidence of false-negative cases was related to those not monitoring both latency and amplitude, to using fewer recording electrodes, and with those surgeons doing more kyphosis corrections.

A carbon fiber implant to aid interbody lumbar fusion. Mechanical testing.

Abstract: A carbon-fiber-reinforced polymer implant has been designed to aid interbody lumbar fusion. The cage-like implant has ridges or teeth to resist pullout or retropulsion, struts to support weight bearing, and a hollow center for packing of autologous bone graft. Because carbon is radiolucent, bony hea

Diagnosis and operative treatment of intraforaminal and extraforaminal nerve root compression.

Abstract: The clinical, radiologic, and operative findings, and clinical results in 26 cases of foraminal nerve root involvement, each treated by variable operative procedures for an existing pathologic condition, were studied. These 26 cases consisted of 8 intraforaminal or extraforaminal lumbar disc herniations and 18 foraminal nerve root entrapments. The cases with an extreme lateral lumbar disc herniation underwent lateral fenestration or osteoplastic hemilaminectomy without concomitant spinal fusion, and showed excellent operative results. A sufficient selective decompression was achieved with a good clinical result in the cases of lumbar spondylosis without preoperative spinal instability, by lateral fenestration or osteoplastic hemilaminectomy. This result suggests that the selective decompression procedure is recommended for cases with reliable preoperative diagnoses. When an intraspinal lesion makes it difficult to diagnose coexisting foraminal nerve root involvement, decompression of the nerve root canal, approaching from medial to lateral, is recommended. The fusion operation should be performed in cases undergoing even a unilateral total facetectomy, regardless of the patient's old age. A correct preoperative diagnosis is crucial in order to obtain satisfactory operative results.

Mechanism of disc rupture. A preliminary report.

Abstract: Lumbar intervertebral disc herniation is thought to be related to senescent changes in the nucleus pulposus except in rare instances of trauma. This investigation provides the first in vitro model of disc prolapse that reliably ruptures discs under physiologically reasonable stress. Fourteen vertebral motion segments with intact posterior elements were loaded repetitively at 1.5 Hz in a combination of flexion (7 degrees), rotation (less than 3 degrees), and compression (1,334 N) for an average of 6.9 hours (range, 3.0-13.0 hours) in a materials testing machine. Loading was terminated when reaction force leveled off for more than 1 hour. Ten discs failed through annular protrusions, and four failed by nuclear extrusion through annular tears, supporting the hypothesis that intervertebral disc prolapse is peripheral in origin. The annulus fibrosus is the site of primary pathologic change.

1991 Volvo Award in basic sciences. Collagen types around the cells of the intervertebral disc and cartilage end plate: an immunolocalization study.

Abstract: Several types of collagen are known to exist in the intervertebral disc in addition to the fibrillar collagens, Types I and II. Although they constitute only a small percentage of the total collagen content, these minor collagens may have important functions. This study was designed to investigate the presence of Types I, II, III, IV, VI, and IX collagens in the intervertebral disc and cartilage end plate by immunohistochemistry, thereby establishing their location within the tissues. Types III and VI collagen have a pericellular distribution in animal and human tissue. No staining for Type IX collagen was present in normal human disc, but in rat and bovine intervertebral disc, it was also located pericellularly. These results show that cells of the intervertebral disc and cartilage end plate sit in fibrous capsules, forming chondrons similar to those described in articular cartilage. In pathologic tissue the amount and distribution of the collagen types, and the organization of the pericellular capsule, differ from that seen in control material.

Trunk muscle and lumbar ligament contributions to dynamic lifts with varying degrees of trunk flexion.

Abstract: This study was done to assess the interplay between muscular and ligamentous sources of extensor moment during dynamic lifting with various loads and flexion angles of the trunk segment for 15 subjects lifting a total of 150 loads. Ligament forces predicted from an anatomically detailed biomechanical model did not generally contribute more than 60 Nm for most of the lifts because the lumbar spine was only flexed to a moderate and constant degree for each load condition. In contrast, additional moment demands associated with increases in hand load were supported by muscle. Although the compression forces on the L4-5 intervertebral disc were fairly insensitive to the interplay between the recruitment of muscle and ligament, the shear force was significantly higher with a greater degree of lumbar flexion. The risk of injury may be influenced more by the degree of lumbar flexion than the choice of stoop or squat technique.

Roentgenographic analysis of posture in spinal osteoporotics.

Abstract: This study was designed to investigate the relationship between postural deformities--including both the spine and lower extremities--and clinical symptoms in spinal osteoporotics. Lateral roentgenographic films of 100 osteoporotic patients taken in a standing position were analyzed. Thoracic kyphosis, a primary deformity of the osteoporotic spine, appeared compensated by the lumbar spine, sacroiliac joint, hip joint, and knee joint, respectively. Low-back pain was highly associated with decreased lumbar lordosis and increased sacropelvic angle, suggesting that the sacroiliac joint was one of the causes of low-back pain.

Treatment of Cervical Spine Injuries with Anterior Plating: Indications, Techniques, and Results

Abstract: This study analyzed 86 patients who sustained a cervical spine injury and who had 93 anterior surgical interventions of the cervical spine. The average age of the patients was 39 years, the mean follow-up 40 months. Twenty-two patients had predominantly vertebral body fractures (burst or tear-drop fractures) and were treated by bisegmental anterior bone grafting and plating. Sixty-four patients had predominantly posterior lesions, either discoligamentous or osteoligamentous, and were treated by unisegmental bone grafting and plating. Forty-three patients were neurologically intact. There were no relevant complications except in one patient, who needed reoperation because of a secondary redislocation due to a technically insufficient osteosynthesis. The technique of anterior bone grafting and plating is shown to be straight-forward, atraumatic, and reliable for predominantly anterior lesions as well as for posterior injuries when performed properly. This clinical experiences does not support experimental data and earlier clinical work, which advocate posterior surgery over anterior surgery and assert that anterior surgery should not be done in predominantly posterior lesions.

Complications of the variable screw plate pedicle screw fixation.

Abstract: In this study, 124 consecutive cases of posterior spinal fusion with variable screw plate fixation were reviewed. In 33 patients (27%), 41 complications were identified. Urinary tract infection without sequelae developed in 13 patients. Dural tear occurred in seven patients and wound hematoma in fiv