摘要:

Study Design.Oxygen concentrations in intervertebral discs were measured in 10 patients during discography and in 13 patients with scoliosis and 11 patients with back pain during spinal surgery. Lactate concentration profiles were measured in 12 of these discs. The discs were graded for degeneration by magnetic resonance maging and histology where possible.Objectives.To determine if oxygen and lactate levels in human discs vary with degree of degeneration. Failure of nutrient transport is thought to lead to disc degeneration.Summary of Background Data.The disc is avascular. Oxygen is used by the disc cells, and lactate is produced. Low oxygen and high lactate concentrations have been measured in the center of healthy animal discs.Methods.Oxygen concentrations were measured amprometrically. The sterilized gold-needle electrode was introduced into the disc during discography or after the disc was exposed surgically via an anterior approach. Concentration profiles of each disc took approximately 5 minutes to measure. Lactate concentrations were measured biochemically on the excised disc segment.Results.Oxygen concentrations were highest at the disc surface and fell toward the center. Lactate concentrations showed the reverse profile. Oxygen levels were very variable, ranging from 5-150 mm Hg in the center of the nucleus. No correlation was seen with age, pathology, or degree of degeneration. Lactate concentrations ranged for the most part from 2 mmol/L to 6 mmol/L.Conclusions.Concentrations of metabolites depend on cellular activity and on transport of the metabolite between the blood supply and the cell. The correlation between degeneration and nutrition cannot be determined only from metabolite concentrations; measurements of metabolic activity and nutrient transport rates also are required.

ISSN:0362-2436    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0362-2436    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Study Design.Two surgical techniques for anterior discectomy were compared biomechanically. The surgical procedures were performed in live, anesthetized, skeletally immature pigs. Spine flexibility was measuredin vitro.Objective.To determine whether endoscopic techniques for discectomy are as effective as open procedures in increasing spine flexibility.Summary of Background Data.Although studies have verified that discectomy increases spine flexibility, no study has confirmed whether endoscopic techniques increase flexibility as effectively as standard thoracotomy, which is a substantially different procedure.Methods.The intervertebral disc between vertebrae T8 and T9 was resected from 30 live, anesthetized, adolescent pigs. In 15 pigs, the chest was opened via thoracotomy of the eighth rib, and the disc was excised. In the other 15 pigs, the disc was removed endoscopically. These motion segments and six intact controls were tested mechanically in side bending, flexion-extension, and axial rotation.Results.No statistically significant differences in flexibility were found between open and endoscopic groups in any loading direction. The statistical power to detect a 20% difference between surgical groups was ≥ 95%.Conclusions.Endoscopic and open techniques were equally effective in increasing spine flexibility. Because endoscopy may reduce surgical morbidity compared with open discectomy, these results support the use of endoscopy for the surgical correction of scoliosis before instrumentation.

ISSN:0362-2436    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0362-2436    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Study Design.Whiplash injuries were studied in an experiment using whole cervical spine specimen.Objectives.To develop a whiplash trauma model that uses a whole cervical spine specimen, and to show the feasibility and unique features of such a model.Summary of Background Data.Whiplash trauma has been simulated in biomechanical experiments using volunteers, whole body cadavers, animals, anthropometric dummies, and mathematic models. These experiments require large facilities, are expensive, and provide limited information about cervical spine injuries.Methods.An alternate approach, in which a benchtop sled accelerating apparatus is used to produce whiplash trauma, has been developed to study such trauma in whole cervical spine specimens. Several transducers were developed to monitor soft tissue injuries during the trauma. The model also provides quantification of injuries to the cervical spine.Results.To assess the feasibility and usefulness of the model, a specimen was traumatized, and the following parameters were monitored during the trauma: linear acceleration of the sled, linear and angular acceleration of the head surrogate, displacements of the head surrogate, loads at T1 and C1 vertebrae, and linear deformations of capsular ligaments and vertebral artery.Conclusions.This model, which incorporates a fresh cadaveric whole human cervical spine specimen, can simulate whiplash trauma effectively and is useful in providing a comprehensive set of clinically relevant information during the trauma. This model gives insight into the complex events and interactions that cause the injuries that occur during whiplash trauma.

ISSN:0362-2436    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Study Design.A single-blinded, randomized treatment study with a follow-up period of 6 months.Objective.To study the long-term consequences of whiplash neck sprain injuries in patients treated with two different regimes during the first 14 days after the car accident. Patients in the first group were encouraged to act as usual,i.e.,continue to engage in their normal, pre-injury activities; that group was compared with another group of patients who were given time off from work and who were immobilized using a soft neck collar. The end point of the comparison was the evaluation of subjective symptoms 6 months after the accident.Summary of Background Data.Few randomized treatment studies have been performed to evaluate the clinical outcome for patients with neck sprain.Method.Patients who participated in the study were recruited from the Emergency Clinic at the University Hospital in Trondheim, Norway. The study group included 201 patients (47% of the study group) with neck sprain that resulted from a car accident. Neck and shoulder movements and subjective symptoms, which were assessed using several different measurements, were assessed during the follow-up period.Results.There was a significant reduction of symptoms from the time of intake to 24 weeks after the treatment period in both groups. There was a significantly better outcome for the act-as-usual group in terms of subjective symptoms, including pain localization, pain during daily activities, neck stiffness, memory, and concentration, and in terms of visual analog scale measurements of neck pain and headache.Conclusions.The outcome was better for patients who were encouraged to continue engaging in their normal, pre-injury activities as usual than for patients who took sick leave from work and who were immobilized during the first 14 days after the neck sprain injury.

ISSN:0362-2436    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Study Design.The authors developed a method of spinous process-splitting laminoplasty using a threadwire saw in a prospective study of 25 patients with cervical myelopathy. This report describes the surgical technique and the results of the expansive midline laminoplasty performed with an threadwire saw.Objectives.To compare the efficacy of midline, threadwire-saw laminoplasty with that of the original spinous process-splitting laminoplasty.Summary of Background Data.The spinous process-splitting laminoplasty was described by Kurokawa in 1982. Although the procedure has a number of theoretical and practical advantages, it has not been widely used because of technical difficulties.Methods.Twenty-five patients who underwent expansive, midline, threadwire-saw laminoplasty from C3 to C7 for cervical myelopathy were studied. The threadwire saw was used to split the spinous processes. The mean follow-up period was 34 months. Neurologic results were evaluated with pre- and postoperative scores, and recovery rates were evaluated by methods described in previous reports using the Japanese Orthopaedic Association scoring system. Radiographic data analyzed included plain radiographs and computed tomography scans. The duration of surgery and the amount of blood lost during this procedure using the threadwire saw were compared with the duration and blood loss that occurred during the original Kurokawa's procedure using a burr.Results.In all cases, good enlargement of the cervical canal was achieved. The mean increase in cervical cross-sectional area was 36.1%, according to computed tomography scans. No dural tears occurred, and no patients experienced any decrease in neurologic function. The neurologic recovery rate was 72%, which was almost same as the neurologic recovery rate in the original procedure. Using the threadwire saw, the mean duration of surgery was 63 minutes shorter and the mean blood loss was 70 cc less than in procedures using burrsConclusions.The application of the threadwire saw to split the spinous processes made Kurokawa's procedure simpler, faster, and safer.

ISSN:0362-2436    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Study Design.Magnetic resonance imaging findings of an increased signal in the cervical cord in patients undergoing surgery for ossification of the posterior longitudinal ligament were analyzed to determined whether an increased signal on T2-weighted images correlated with a poorer outcome.Objectives.To clarify whether preoperative magnetic resonance imaging findings of a high signal in the cord constitute a poor prognostic factor.Summary of Background Data.The importance of a high, T2-weighted, intramedullary signal on preoperative magnetic resonance studies in patients undergoing surgery for ossification of the posterior longitudinal ligament requires further clarification.Methods.Of 91 patients having cervical surgery for ossification of the posterior longitudinal ligament, 26 had a history of minor trauma. High, T2-weighted signals in the cord were noted in 23 patients who had sustained trauma and in 39 patients who had no history of trauma. Patients were divided into four groups according to the presence or absence of a high cord signal and/or a trauma history. Pre- and postoperative Japanese Orthopaedic Association scores and recovery ratios then were evaluated.Results.The pre- and postoperative Japanese Orthopaedic Association scores and recovery ratios of the patients with a high signal and a trauma history were significantly less than those with no high signal but with a trauma history. Among the patients with no history of trauma, however, there were no significant differences in the pre- and postoperative JOA scores and recovery ratios between the patients with a high signal and those with no high signal.Conclusion.A high preoperative cord signal on T2-weighted magnetic resonance images for patients undergoing surgery for ossification of the posterior longitudinal ligament constitutes a poor prognostic factor, when trauma has played a role.

ISSN:0362-2436    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Study Design.A case-control study of 24-hour urinary melatonin production in patients with adolescent idiopathic scoliosis.Objectives.To address the controversy over the role of melatonin deficiency in adolescent idiopathic scoliosis by measuring total melatonin production over a 24-hour period.Summary of Background Data.An association between melatonin deficiency and experimental scoliosis has been suggested in several animal species. Recent work has failed to show a deficiency in humans with scoliosis. However, this conclusion was based on single urinary estimations. In this study the period assayed was standardized to 24-hours for all patients to include the full diurnal cycle of melatonin excretion.Methods.Consecutive patients at an outpatient clinic for adolescent idiopathic scoliosis were recruited as subjects for this study, and patients from a fracture clinic who were of similar age and gender were recruited as controls at their final follow-up examination after the healing of their fracture. Patients and control individuals collected urine over a 24-hour period that was divided into consecutive day and night collections of 12 hours each. Total urinary excretion of 6-sulphatoxy melatonin was determined by radioimmunoassay for each 12-hour period in patients and control individuals.Results.No significant difference in diurnal, nocturnal, or total urine 6-sulphatoxy melatonin excretion was found between adolescent patients with idiopathic scoliosis and controls of similar age and gender. There was also no difference between the two groups when 6-sulphatoxy melatonin excretion was corrected for body weight, body surface area, and body mass index. Nor was there a significant difference between 6-sulphatoxy melatonin excretion of patients with scoliosis whose curves failed to progress over the course of a year and the excretion of those who underwent surgery.Conclusions.In adolescent idiopathic scoliosis, neither the presentation with a stable spinal deformity, nor presentation with a severe deformity requiring surgery is associated with melatonin deficiency.

ISSN:0362-2436    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Study Design.A retrospective study of 44 museum cases of spinal osteoid osteoma or osteoblastoma and a meta-analysis using 421 additional cases from a review of the literature.Objectives.To identify the factors that are associated with the development of scoliosis in these patients.Summary of Background Data.Painful scoliosis is a well-recognized presentation of spinal osteoid osteoma and osteoblastoma and is considered to be secondary to pain-provoked muscle spasm on the side of the lesion. Previous studies have been based on small numbers of patients that did not permit statistical validation of the reported observations.Methods.Eight factors were assessed including: age, gender, duration of symptoms, site of lesion in the spine, vertebral level of lesion, site of lesion in the individual vertebra, type of lesion, and Cobb angle at presentation. Reports were reviewed only if the presence or absence of scoliosis could be determined. Statistical analyses initially were performed on the museum cases and then on a combination of museum cases and cases from the literature.Results.Overall, 63% of subjects had scoliosis. The lesions were typically present on the concave aspect of the curve. Three cases of scoliosis from the literature involved lesions that were reported to be on the convexity. Scoliosis is significantly more common in cases of osteoid osteoma than in cases of osteoblastoma (P< 0.0001); lesions are more common in the thoracic and lumbar regions than in the cervical region (P< 0.0001), in lower cervical region than in the upper cervical region (Pvalue = 0.0027), and they are more commonly located to one side of the midline (P< 0.0001). Age, gender, and duration of symptoms were of no significance.Conclusions.The findings support the concept that scoliosis is secondary to asymmetric muscle spasm in patients with spinal osteoid osteoma or osteoblastoma.

ISSN:0362-2436    

出版商:OVID    

年代:1998

数据来源: OVID