摘要:

Study Design.The vertebral levels of dorsal root ganglia innervating the dorsal portion of the L5–L6 intervertebral disc were investigated in rats using a retrograde transport method. The pathways and functions of nerve fibers supplying the dorsal portion of the disc were determined by denervation and immunohistochemistry.Objectives.The dorsal portion of the lumbar intervertebral disc has been reported to be innervated segmentally, but anesthetic block of the paravertebral sympathetic trunks and the L2 spinal nerve can relieve discogenic low back pain. In the current study, the sensory innervation of the dorsal portion of the L5–L6 intervertebral disc was investigated, because the disc anatomically corresponds to the L4–L5 disc in humans, and the dorsal portion of the human L4–L5 disc is frequently subject to injury that causes low back pain.Methods.A retrograde transport of Fluoro-Gold (F-G; Fluorochrome, Denver, CO) was used. Subjects included nontreated control (n = 32) and sympathectomized rats in which paravertebral sympathetic trunks were removed from L2 to L3 (n = 9). In a ventral approach, Fluoro-Gold crystals were placed on the dorsal portion of the L5–L6 disc, and labeled neurons in the bilateral dorsal root ganglia from T10 to L6 were counted.Results.Fluoro-Gold crystals did not leak from the dorsal portion of the L5–L6 disc in 14 of the 32 nontreated rats and in 5 of the 9 sympathectomized rats. These rats were used for analysis. Fluro-Gold–labeled neurons were found in dorsal root ganglia from T13 to L6 in the 14 control rats but only from L2 to L6 in the 5 sympathectomized rats.Conclusion.The dorsal portion of the L5–L6 disc of rats was shown to be multisegmentally innervated by the T13 to L6 dorsal root ganglia. The sensory fibers from T13, L1, and L2 dorsal root ganglia were shown to innervate the dorsal portion of the L5–L6 disc through the paravertebral sympathetic trunks. In contrast, those from the L3–L6 dorsal root ganglia may innervate the dorsal portion of the L5–L6 disc through the sinuvertebral nerves.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.This static, nondestructive,in vitrobiomechanical study examines anterior solid rod construct stiffness following the addition of multilevel, threaded cortical bone dowels in a bovine model. A comparison is made with a clinically relevant posterior construct with and without an anterior release.Objectives.To determine if the addition of solid, multilevel disc space implants will increase construct rigidity, while maintaining or enhancing anterior column length.Summary of Background Data.Anterior instrumentation for thoracolumbar and lumbar scoliosis has achieved greater correction and preserved distal motion segments; however, kyphosis over the instrumented segments and nonunion have been observed more frequently than with posterior segmental spinal instrumentation.Method.Fifteen calf spines underwent mechanical testing. Group A (n=7) included anterior constructs: 1) intact, 2) anterior release/rod/rib graft (L2–L5), and 3) anterior release/rod/dowels (L2–L5). Group B (n=8) included posterior constructs: 1) intact, 2) posterior rod without anterior release (T13–L5), 3) posterior rod (T13–L5)/anterior release/rib graft (L2–L5). The protocol included axial compression (-600N), axial rotation (+ 7 Nm), flexion/extension (+ 7.5 Nm), and lateral bending (+ 7.5 Nm). An anterior extensometer measured segmental displacements to calculate construct stiffness. Lateral radiographs evaluated alignment for the anterior constructs. Statistical analysis involved a one way analysis of variance (ANOVA) and a Student-Newman-Keuls post hoc test.Results.All reconstructions restored stiffness to intact values with the exception of the dowels alone in axial rotation. The rod/dowel construct was stiffer than all other groups in axial compression, flexion/extension, and lateral bending, with the exception of the posterior rod without discectomy, which was superior in flexion and statistically similar in extension, lateral bending, and axial rotation. The anterior construct with rib graft was equivalent to the posterior construct with rib graft in all modes of testing. The dowels created greater lordosis than the bicortical rib grafts.Conclusions.Disc space augmentation increased stiffness except in axial rotation, in which values were restored to the intact level. Stiffness was superior to a clinically relevant posterior instrumentation comparison group following anterior release, and was equivalent to a posterior construct without anterior release except in anterior flexion. In addition, the implants enhanced lordosis. Increased rigidity should improve rates of arthrodesis, while maintenance of sagittal alignment may prevent pathologic compensatory curves in adjacent spinal segments. Further research is required to determine the optimal method of achieving structural interspace support.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.The study involved elderly patients (age ≥65), who underwent treatment for cervical spondylotic myelopathy by canal-expansive laminoplasty.Objectives.To determine the factors that influence the operative results of canal-expansive laminoplasty for treatment of cervical spondylotic myelopathy in elderly patients.Summary of Background Data.Although there have been previous reports of many operative procedures, to the authors’ knowledge there are no reports on the results of surgical treatment for cervical spondylotic myelopathy in elderly patients, treated by a unified surgical procedure. To date, no attempts have been made to predict the results of these procedures.Methods.Forty-seven patients (age ≥65) who underwent canal-expansive laminoplasty were reviewed in this study. The severity of the clinical picture and the quality of operative results were graded according to the Japanese Orthopaedic Association scoring system.Results.Of the 13 patients whose period of disability persisted for less than 3 months before the operation, 12 were able to walk after surgery. The operative results of patients more than 80 years of age were not significantly different from those of patients aged between 65 and 79 years. Results of multiple regression analysis indicate that the predictive probability of the postoperative motor function score of the lower extremities was 70%.Conclusions.The severity of the clinical picture and the duration of symptoms influenced the outcome of the operation. Despite the advanced age of some patients (>80), the operation increased the chance of recovery from the disease.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.A retrospective, follow-up study.Objectives.To assess the effects of conventional surgery for lumbar disc herniation over an extended period of time and to examine factors that might correlate with unsatisfactory results.Summary of Background Data.Although the short-term results of lumbar discectomy are excellent when there is a proper patient selection, the reported success rates in the long-term follow-up studies vary, and few factors have been implicated for an unsatisfactory outcome.Methods.One hundred-nine patients with surgically documented herniated lumbar disc were analyzed, retrospectively, by an independent observer. Long-term follow-up (mean 12.2 years) was done by a mailed, self-report questionnaire that included items about pain relief in the back and leg, satisfaction with the results, need for analgesics, level of activity, working capacity, and reoperations. Subjective disability was measured by the Oswestry questionnaire. Radiographic review was carried out in 66% of patients. End results were assessed using the modified Stauffer–Coventry’s evaluating criteria. Several variables were examined to assess their influence to the outcome.Results.The late results were satisfactory in 64% of patients. The mean Oswestry disability score was 18.9. Of the 101 patients who had primary procedures, 28% still complained of significant back or leg pain. Sixty-five percent of patients were very satisfied with their results, 29% satisfied, and 6% dissatisfied. The reoperation rate was 7.3% (8 patients), about one-third of which was due to recurrent disc herniation. Sociodemographic factors predisposing to unsatisfactory outcome, including female gender, low vocational education, and jobs requiring significant physical strenuousness. Disc space narrowing was common at the level of discectomy, but was without prognostic significance.Conclusions.The long-term results of standard lumbar discectomy are not very satisfying. More than one-third of the patients had unsatisfactory results and more than one quarter complained of significant residual pain. Heavy manual work, particularly agricultural work, and low educational level were negative predictors of a good outcome. These indicators should be used preoperatively to identify patients who are at high risk for an unfavorable long-term result..

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.A 10-year follow-up evaluation of the effectiveness of school screening for scoliosis performed in a closed island population.Objectives.To evaluate the diagnostic accuracy of methods used for screening scoliosis and to re-examine the long-term effectiveness of the school scoliosis screening program.Summary of Background Data.The diagnostic accuracy of the forward-bending test and the long-term efficacy of the screening programs have not been clearly established.Methods.In 1987, 2700 pupils aged 8 to 16 years from the island of Samos were screened for scoliosis. The Adams forward-bending test, Moire topography, the scoliometer, and the humpometer were used. Radiologic evaluation of the spine was available for each pupil and the number of false-negative and false-positive results of the screening methods was calculated. Subsequently, sensitivity, specificity, and positive and negative predictive values were estimated for each screening technique. Pupils found positive for spinal deformity were then followed up regularly at yearly intervals. In 1997, all positive subjects attended a 10-year clinical and radiologic follow-up, and the remaining subjects were re-evaluated by a postal questionnaire and were clinically examined if necessary.Results.Spinal deformity was found in 153 (5.66%) pupils. Scoliosis (defined as a spinal curvature ≥10°) was found in 32 pupils, for a prevalence of 1.18%. For scoliosis, the Adams forward-bending test showed a number of false-negative results (in five cases), for a sensitivity of 84.37% and specificity of 93.44%. The sensitivities of Moire topography, the humpometer, and the scoliometer were 100%, 93.75%, and 90.62%, respectively, and specificity was 85.38%, 78.11%, and 79.76% respectively. The negative predictive value of the forward-bending test was inferior to those of the other methods. During this scoliosis screening program, if cutoff limits for referral had been used, such as the asymmetry of two Moire fringes, a humpogram deformity of (D+H) = 10 mm, and 8° of scoliometer angle, it would have been possible to reduce radiologic examination by 89.4%. Three (0.11%) pupils aged between 12 and 14 years with scoliotic deformities greater than 20° underwent satisfactory nonoperative treatment with Boston braces. One pupil with a 40° thoracic curvature, underwent satisfactory surgical treatment because of progression 1 year later. Of the 121 spinal deformities with an initial Cobb angle less than 10°, 44 (35.8%), and of the 29 scoliotic deformities with an initial Cobb angle between 10° and 20°, 14 (48.3%) progressed (a Cobb angle difference of at least 5° in more than one examination). Observation and physiotherapy were the only treatments applied to all except one of the pupils in these groups.Conclusions.The Adams forward-bending test cannot be considered a safe diagnostic criterion for the early detection of scoliosis (especially when it is used as the only screening tool) because it results in an unacceptable number of false-negative findings. For the early detection of scoliosis, a combination of back-shape analysis methods can be safely used with the introduction of cutoff limits for referral being a useful procedure. The incidence of significant scoliosis is low, and its natural history seems to be independent of early detection. The widespread use of school scoliosis screening with the use of the forward-bending test must be questioned.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.Retrospective chart and radiographic film review.Objectives.To discern the deformity problems in diastrophic dysplasia and to report our results in surgical treatment.Summary of Background Data.Due to the rarity of the problem, the literature is very scanty as to the indications for surgery or the best technique.Methods.Analysis of radiographic film for scoliosis, kyphosis, lordosis, and decompensation before surgery, after surgery, and at follow-up. Analysis of charts for complications and problems.Results.The most common deformity pattern was a double thoracic kyphosis (79°/97°) with a true kyphosis at the junction of the two scolioses (101°). Combined anterior-posterior arthrodesis gave the best results.Conclusions.Very severe deformity can occur in children with diastrophic dysplasia, even at a young age. Prompt anterior-posterior arthrodesis can prevent catastrophic deformity.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.Brief (30-second) isometric trunk extensions at 5%, 20%, 40%, 60%, and 80% of maximal voluntary contraction (MVC) and 3 minutes of prolonged trunk extension (20% MVC) in erect position were studied in nine healthy male subjects.Objectives.To investigate the intercorrelation between intramuscular pressure and tissue oxygenation of the paravertebral muscles during submaximal isometric contractions and further, to evaluate paravertebral electromyogram and intramuscular pressure as indicators of force development.Summary of Background Data.Local physiologic responses to muscle contraction are incompletely understood.Methods.Relative oxygenation was monitored with noninvasive near-infrared spectroscopy, intramuscular pressure was measured with a transducer-tipped catheter, and surface electromyogram was monitored at three recording sites.Results.The root mean square amplitudes of the paravertebral electromyogram (L4, left and right; T12, right) and intramuscular pressure measured in the lumbar multifidus muscle at L4 increased with greater force development in a curvilinear manner. A significant decrease in the oxygenation of the lumbar paravertebral muscle in response to muscle contraction was found at an initial contraction level of 20% MVC. This corresponded to a paravertebral intramuscular pressure of 30–40 mm Hg. However, during prolonged trunk extension, no further decrease in tissue oxygenation was found compared with the tissue oxygenation level at the end of the brief contractions, indicating that homeostatic adjustments (mean blood pressure and heart rate) over time were sufficient to maintain paravertebral muscle oxygen levels.Conclusion.At a threshold intramuscular pressure of 30–40 mm Hg during muscle contraction, oxygenation in the paravertebral muscles is significantly reduced. The effect of further increase in intramuscular pressure on tissue oxygenation over time may be compensated for by an increase in blood pressure and heart rate. Surface electromyogram amplitudes and intramuscular pressure can be used as indicators of paravertebral muscle force.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.We conducted a prospective study with a 2-year follow-up.Objective.To compare pain, functional limitations, and work status indices as measures of outcome among back pain patients.Summary of Background Data.Work status, pain, and functional limitations indices are often considered as interchangeable outcome measures in back pain research. This perspective has been criticized by several authors, who argue that each of these outcome measures reflects a different construct that may vary independently of the others.Methods.The study was conducted on 720 patients, who sought care for back pain in primary care settings of a large health maintenance organization in 1989–90, and were interviewed one month and two years later. &KHgr;2analyses and receiver operating characteristic curves were used to compare the accuracy of a pain rating and a modified 16-item Roland–Morris score in classifying patients on work status and on the change in work status over time.Results.Moderate agreement between the pain and functional limitations measures and work status was observed. Pain and functional limitations change scores agreed moderately with improvement in work status, but were poorly associated with decline in work status.Conclusions.Although the pain, functional limitations, and work status indices examined in this study are related, they are not equivalent and should not be regarded as interchangeable. These results argue for a clearer distinction of outcome measures in back pain research.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.A prospective clinical trial was conducted.Objectives.To determine the feasibility of removing activity restrictions after surgery and encouraging early return to work; to ascertain the clinical and behavioral response to such a strategy; and to identify factors predictive of early return to work, preparatory to possible randomized clinical trials.Summary of Background Information.Current practice usually entails several weeks to several months of restricted activities after lumbar discectomy to avoid disc “reinjury.” Earlier work has suggested these restrictions may not be necessary.Methods.One hundred fifty-two consecutive working patients undergoing limited open discectomy for herniated lumbar intervertebral disc were treated postoperatively with no activity restrictions. Patients were encouraged to return to full activities as soon as possible. The patients were followed for a minimum of 2 years (average follow-up time = 4.8 years). At follow-up, an independent examiner evaluated each patient and collected further postoperative data.Results.One hundred forty-nine of the 152 patients (98%) returned to work. The average work loss was 1.2 weeks and 148 of 149 patients had returned to full duty by 8 weeks. Approximately one-third of the group returned to work within 1 week of surgery (32%), many the next day. Statistical analysis demostrated very early return to work did not correlate with either recurrent sciatica, reoperation for reherniation, or ultimate clinical outcome. Seventeen patients (11.2%) had possible reherniations (recurrent sciatica) and eight underwent reoperation (5.3%).Conclusion.Lifting of postoperative activity restrictions after limited discectomy allowed shortened time to return to work relative to the 4 to 16 weeks commonly recommended. Complication rates appear comparable to those reported in the literature for patients under postoperative restrictions. Postoperative restrictions may not be necessary in most patients.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Study Design.In this prospective study, the results of treating unstable thoracolumbar and lumbar injuries with Cotrel–Dubousset instrumentation were investigated.Objective.To determine the pain and work status of the patients, to evaluate neurologic status, and to assess the efficacy of instrumentation in the short term.Summary of Background Data.Short-segment pedicle screw construct is the method of choice for reduction and stabilization of unstable thoracolumbar spinal injuries. Many investigators have recently reported a high rate of instrument failure. In this study, the use of segmental transpedicular fixation two levels above the kyphosis decreased instrument failure and sagittal collapse.Methods.Thirty patients, who had unstable thoracolumbar and lumbar spinal injuries, underwent application from a posterior approach of Cotrel–Dubousset instrumentation two levels above and one below at the thoracolumbar junction and short segment fixation in the lumbar area. Radiologic parameters were evaluated before and after surgery.Results.The mean follow up was 31 months (range, 25–49) months. There were statistically significant differences between the pre- and postoperative values in all radiologic parameters. Neurologic status improved in 70% of the patients, with a mean Frankel grade of 1.3 grades.Conclusions.Cotrel–Dubousset instrumentation provided spinal stability in unstable injuries, forming a rigid construct and restoring physiologic thoracolumbar and lumbar postural contours because of its highly corrective effect in the sagittal profile with no loss of correction.

ISSN:0362-2436    

出版商:OVID    

年代:1999

数据来源: OVID