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Prevention of postlaminectomy scar formation.

An animal experimental study was performed to investigate prevention of scar formation under lumbar laminectomy by using new biodegradable interposing materials-- polylactic acid (PLA) foam and membrane. The experimental animals consisted of 32 dogs, 16 control and 16 experimental. The experimental surgery consisted of L5 or L6 complete laminectomy and covering of the laminectomy defect with the experimental materials. The same procedure but without the covering of the laminectomy defect was performed on the control group animals. Animals were sacrificed at varying intervals (2-52 weeks) and the lumbar spines were evaluated with histologic preparations. The PLA membrane is found to be a promising material for prevention of scar tissue extension and adhesion after laminectomy but has a problem of marginal fitting. PLA foam is found to behave as a scaffold for scar tissue extension and adhesion onto the nerve. Other foamy materials such as gelatin foam or avitane are probably behaving similarly, causing scar tissue extension and adhesion. The new materials were found to be completely biocompatible and slowly biodegradable. A combined use of posteriorly convexed stiff PLA membrane and marginal gap filler with PLA foam may provide solutions for both prevention of scar tissue extension and adhesion and prevention of postlaminectomy spinal stenosis.

Animals↗

Degenerative spondylolisthesis. Its surgical management.

Little attention has been given to the amount of further slip and the success rate after decompression for degenerative spondylolisthesis. In this retrospective study, the answers to the following were sought: (1) Did decompression relieve symptoms; (2) Which decompressive technique was best; (3) Did further slip occur; (4) Did further slip make patients worse? Seventeen patients were available for an average 20-month follow-up. Six patients had a decompression laminectomy with facetectomies, and 11 had a decompression laminectomy with foraminotomies. None was fused. Patients rated their results as better or worse at follow-up. Nine were better, eight were worse. Five of six who had laminectomies with facetectomies were better. Only four of 11 who had laminectomies with foraminotomies were better. The average further slip was 3 mm. Further slip did not correlate with type of decompression, symptoms, and patients' subjective results. We recommended that a decompression laminectomy for degenerative spondylolisthesis include a facetectomy. Further study is necessary to evaluate the efficacy of a fusion in controlling chronic back pain in the postdecompressed patient with degenerative spondylolisthesis.

Aged↗

Surgical management of lumbar spinal stenosis.

Eighty consecutive patients with lumbar spinal stenosis surgically treated during a 5-year period by the author were reviewed. Patients were placed in the following categories: lateral spinal stenosis (10), central-mixed stenosis (29), spinal stenosis after laminectomy and/or fusion (32), and spinal stenosis with degenerative scoliosis (9). Contrast-enhanced computed tomographic (CT) scans were helpful in determining the levels requiring decompression. However, in the multiply operated patient, contrast-enhanced CT scans were misleading in six patients. Patients with lateral spinal stenosis were treated with unilateral laminectomy and partial facetectomy. The 29 patients with central-mixed stenosis underwent decompressive laminectomy and bilateral facetectomies. Six fusions were done. In the nine patients with spinal stenosis and scoliosis, concaveside partial facetectomies and laminectomies were done as well as spinal fusions. The 32 patients with spinal stenosis after previous laminectomy and spinal fusions were the most difficult group to analyze, and their treatment was the least standardized. There were 19 good, eight fair, and five poor results in those who had undergone previous surgery. Fifty-seven of the 80 patients (71%) experienced a good result from their surgical treatment.

Adult↗

An analysis of the posterior epidural ligament role on the cervical spinal cord.

STUDY DESIGN: Laminectomy was performed on cats to destroy the posterior epidural ligament. Evoked potentials and spinal cord blood flows quantified the spinal cord function before and after cervical flexion. OBJECTIVES: This work describes a relationship between the loss of the posterior epidural ligaments and cervical spinal cord injury. SUMMARY OF BACKGROUND DATA: The posterior epidural ligaments of the human cervical spine have been recently described. These ligaments theoretically prevent injury to the spinal cord by resisting collapse of the dura during cervical flexion. METHODS: The animals were divided into three experimental groups: 1) control: no laminectomy and standard position, 2) flexion control: no laminectomy and known imposed flexion, 3) laminectomy (C3-C7) and flexion. Motor-evoked potentials and evoked spinal cord potentials were recorded to quantify the spinal cord functions. Radioactive microspheres were used to quantify ischemia in the spinal cord. RESULTS: Control subjects showed blood flows of 36 mL/100 g/min (C3-C4) to 46 mL/100 g/min (C7-C8). Flexion control subjects did not experience significant reductions in blood flows or substantial change in evoked potentials. The laminectomy plus flexion group experienced reduced blood flows and substantial motor-evoked potentials and slight evoked spinal cord potential changes with 50 degrees, 60 degrees, and 70 degrees flexion. Blood flow reduction was greater in the anterior half of the C7-C8 segments compared with the posterior half at 60 degrees flexion. Evoked spinal cord potentials were less vulnerable than motor-evoked potentials. CONCLUSIONS: The role of the posterior cervical epidural ligaments is to anchor the posterior dura mater to the ligamentum flavum. Loss of the ligaments allows anterior displacement of the posterior dura mater in flexion. Abnormal distribution of or lack of the cervical posterior epidural ligaments may lead to flexion myelopathy.

Animals↗

Cost-effectiveness of fusion with and without instrumentation for patients with degenerative spondylolisthesis and spinal stenosis.

STUDY DESIGN: A cost-effectiveness study was performed from the societal perspective. OBJECTIVE: To evaluate the costs and benefits of laminectomy alone and laminectomy with concomitant lumbar fusion for patients with degenerative lumbar spondylolisthesis and spinal stenosis. SUMMARY OF BACKGROUND DATA: Costs, probabilities, and utilities were estimated from the literature. Short-term risks considered were perioperative complications, the probability of the fusion healing, and the probability that surgery will relieve symptoms. Long-term risks considered were recurrence of symptoms and reoperation. METHODS: The 10-year costs, quality-adjusted life years, and incremental cost-effectiveness ratios (reported as dollars per quality-adjusted year of life gained) were calculated using a Markov model. Sensitivity analysis was performed on all variables using clinically plausible ranges. RESULTS: Laminectomy with noninstrumented fusion costs $56,500 per quality-adjusted year of life versuslaminectomy without fusion. The cost-effectiveness of laminectomy with noninstrumented fusion was most sensitive to the increase in quality-of-life associated with relief of severe stenosis symptoms. The cost-effectiveness ratio of instrumented fusion compared with noninstrumented fusion was $3,112,800 per quality-adjusted year of life. However, if the proportion of patients experiencing symptom relief after instrumented fusion was 90% as compared with 80% for patients with noninstrumented fusion, then the cost-effectiveness ratio of instrumented fusion compared with noninstrumented fusion would be $82,400 per quality-adjusted year of life. CONCLUSIONS: The cost-effectiveness of laminectomy with noninstrumented fusion compares favorably with other surgical interventions, although it depends greatly on the true effectiveness of these surgeries to alleviatesymptoms and on how patients value the quality-of-life effect of relieving severe stenosis symptoms. Instrumented fusion was very expensive compared with the incremental gain in health outcome. Better data on the effectiveness of these alternative procedures are needed.

Cost-Benefit Analysis↗

Treatment and outcome of 83 children with intraspinal neuroblastoma: the Pediatric Oncology Group experience.

PURPOSE: To investigate whether the rate of neurologic recovery or the incidence of long-term sequelae differed for children with neuroblastoma (NB) initially treated with chemotherapy versus surgical decompression with laminectomy, we reviewed the Pediatric Oncology Group (POG) experience. PATIENTS AND METHODS: A retrospective review of children diagnosed with intraspinal NB registered on POG NB Biology Protocol 9047 was performed. Survival, neurologic outcome, and orthopedic sequelae were evaluated according to age of the patient at diagnosis, stage of disease, duration and severity of neurologic symptoms, and therapeutic intervention. RESULTS: Between May 1990 and January 1998, 83 children with intraspinal NB were entered onto the study. Five-year survival for this cohort of patients was 71% +/- 9%. Forty-three (52%) of the patients had neurologic symptoms at diagnosis. After treatment, six of 15 severely affected patients, who presented with paralysis, completely recovered neurologic function. Two of five patients with moderate deficits, consisting of paresis and bowel/bladder dysfunction, completely recovered neurologic function. Seventeen of 22 assessable children, who had mild symptoms comprised of paresis alone, fully recovered. Seven of 24 assessable patients who had undergone laminectomy developed scoliosis, whereas spinal deformities were only detected in one of 49 assessable patients managed without laminectomy (P =.001). CONCLUSION: The frequency of complete neurologic recovery in children with intraspinal NB inversely correlated with the severity of the presenting neurologic deficits. The rate of neurologic recovery was similar for patients treated with chemotherapy compared to those managed with laminectomy. Fewer orthopedic sequelae were observed in the children managed with chemotherapy than were seen in children managed with laminectomy.

Adolescent↗

Spinal cord energy metabolism in normal and postlaminectomy cats.

The purpose of this study was to determine 1) normal concentrations of adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), phosphocreatine (P-creatine), glucose, lactate, and pyruvate in upper (L-2) and lower (L-5) feline lumbar spinal cord, and 2) whether previously reported laminectomy-induced reduction in spinal cord blood flow (SCBF) resulted in disturbance of spinal cord energy metabolism. Concentrations of ATP, P-creatine, pyruvate, and glucose were significantly higher at L-5 than at L-2, probably as the result of larger amounts of gray matter at L-5 than L-2. Significant increases in ADP and AMP levels were the only metabolite changes noted 15 minutes following laminectomy. The authors speculate that the increase in ADP and AMP is due to a laminectomy-induced stimulation of ATP utilization. However, lack of change in other metabolites implies an efficient energy homeostasis. These results indicate that although laminectomy can reduce SCBF, the degree of this reduction is insufficient to adversely affect spinal cord energy metabolism. Thus, tissue from beneath or near the laminectomy site is viable and essentially normal.

Adenosine Diphosphate↗

The reduction of postlaminectomy peridural fibrosis in rabbits by a carbohydrate polymer.

Spinal peridural fibrosis following total laminectomy in New Zealand White rabbits was significantly decreased by the intraoperative application of GT1587, a semi-synthetic carbohydrate polymer. The application of a similar polymer, GT1043, or phosphate-buffered saline (PBS) was not as effective. Laminectomies were performed at L-2 and L-4 in 25 rabbits. Absorbable gelatin sponge soaked with GT1043, GT1587, or PBS was applied in a blinded fashion to the operative sites, with untreated (sham) laminectomy sites serving as controls. Animals were sacrificed after 2 or 4 weeks. The extent of peridural fibrosis was evaluated by gross microdissection and histological analysis. Dense scar formation and dural adhesions were evident at both time intervals in the sham- and PBS-treated laminectomy sites. The sites treated with GT1587 showed significantly decreased peridural scar formation and dural adhesions, whereas GT1043 treatment caused modest reduction of scar formation at only the 2-week examination. The healing of skin and lumbosacral fascia was not affected by treatment of the laminectomy site with GT1587. These results suggest that GT1587 may prove beneficial in preventing postlaminectomy dural adhesions and peridural fibrosis in humans.

Animals↗

[Static and dynamic modifications of the cervical spine after laminoplasty for cervical spondylotic myelopathy].

PURPOSE OF THE STUDY: Cervical laminoplasty has been widely used in Japan as the treatment of progressive cervical myelopathy. However, in 1993, Guigui reported that extensive cervical laminectomy was enough for the treatment of cervical myelopathy secondary to stenotic conditions. The purpose of this report was to compare the results of extensive laminectomy as reported by Guigui in 1998 with those of laminoplasty in our series using exactly the same criteria for anatomic analysis. MATERIAL AND METHODS: Thirty patients aged over 40 years who underwent a spinous process splitting laminoplasty using a threadwire saw from C3 to C7 without fusion for cervical spondylotic myelopathy were reviewed retrospectively with an average follow-up of 3.7 years. Functional results were evaluated according to the Japanese Orthopedic Association scoring system for cervical myelopathy. Lateral views in the neutral position, in flexion, and in extension of the preoperative cervical roentgenograms were analyzed in comparison with the last follow-up films in order to identify the change in the curvature of the cervical alignment, in the range of neck motion, in the intervertebral angular mobility, and in the anteroposterior displacement of the vertebral bodies, and finally to identify the incidence of spinal instability. These data were compared with those of extensive laminectomy published by Guigui. RESULTS: Seven patients (23%) developed postoperative changes in cervical spine curvature. Only one patient had a new destabilized level postoperatively. No patient required new surgery. Compared with the results obtained after extensive cervical laminectomy, incidence of new destabilized level or aggravated level was statistically lower after laminoplasty than after laminectomy. CONCLUSION: Spinous process splitting laminoplasty causes an ossification between the remaining spinous process and an unexpected fusion of the lateral mass. These results may prevent postoperative segmental destabilization.

Adult↗

Cervical stability after foraminotomy. A biomechanical in vitro analysis.

Laminectomy or facetectomy of the cervical spine, or both, may be needed for decompression of the spinal cord or of the nerve-roots. Acute stability of the cervical spine was tested after laminectomy and progressive staged foraminotomies in an in vitro model. Twelve cervical spines from human cadavera were used in the experiment. Biomechanical testing included the application of an axial load, the application of a flexion and extension moment, and the application of a torsional moment. Each specimen was tested intact, after laminectomy of the fifth cervical vertebra, and after progressive foraminotomy of the sixth cervical root. Foraminotomy was performed by resection of 25, 50, 75, and 100 per cent of the facet joint and capsule. Torsional stiffness decreased dramatically when more than 50 per cent of the facet had been resected. Statistically equivalent subsets were the intact specimen, laminectomy, 25 per cent facetectomy, and 50 per cent facetectomy in one subset, and 75 and 100 per cent facetectomy in the least-stiff subset. Flexion-moment testing showed that the posterior strain did not differ among three groups: the intact specimens, those that had been treated with laminectomy, and those that had been treated with a 25 per cent facetectomy. The 50 per cent facetectomy resulted in a 2.5 per cent increase in posterior strain, and the 75 or 100 per cent facetectomy, in a 25 per cent increase in posterior strain compared with the intact specimen. Segmental hypermobility of the cervical spine results if a foraminotomy involves resection of more than 50 per cent of the facet.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Unstable fractures of the thoracolumbar spine: a 10-year experience at Sacré-Coeur Hospital.

UNLABELLED: In a 10-year period, 108 unstable fractures involving the thoracolumbar junction (T11 to L2) were treated. This study evaluates the influence of the different treatments on the rate of complication, reduction of the fracture, and neurological recovery. METHODS: mechanism of injury, initial treatment and delay, neurologic deficit, operative findings, and duration of hospitalization were recorded. X-rays were reviewed for classification of fracture, measurement of deformity, and for instability scoring according to White and Panjabi's criteria. Seventy-seven patients were examined and nine more interviewed by telephone. RESULTS: a flexion-rotation injury occurred in 65% and a burst-fracture in 29%. A laminectomy was performed in 30 patients and Harrington instrumentation and fusion in 71 patients. Sixteen patients were treated conservatively. Fifty-five patients presented either a complete or partial neurological deficit. Seventy-five complications were noted and were more frequent in the laminectomy group. The instrumented group showed a clear tendency for earlier ambulation and discharge and pain level was found to be less. An increased residual deformity was found in patients treated by laminectomy, short fusion, and by nonsurgical modality. The neurologic recovery in the laminectomy and the nonlaminectomy group was not significantly different. Spinal realignment was better in the group where an instrumentation of five levels or more was performed and where posterior elements were not removed by laminectomy.

Adolescent↗

The effect of postlaminectomy spinal instability on the outcome of lumbar spinal stenosis patients.

Between 1986 and 1990, 37 of 72 patients undergoing decompressive lumbar laminectomy with medial facetectomy for lumbar stenosis at The Ohio State University were seen in follow-up at a mean of 31 months (range, 14-63 months) after their laminectomy and were evaluated by questionnaire, detailed neurologic examination, and static and dynamic lumbar radiographs. Thirteen patients who had undergone fusion or who had extenuating medical circumstances were excluded, leaving 24 patients for whom laminectomy was the sole treatment for lumbar stenosis. Postoperatively, normal walking improved from 4 to 45% of patients, sensory deficits decreased from 63 to 25%, and ability to perform most or all desired activities increased from 25 to 70%. Urinary function was unchanged. Thirteen patients (54%) showed radiographic signs of instability. All patients who were declared radiographically stable could walk without a prosthetic aid or normally; 62% of the unstable patients required aid for walking. All of the patients with a poor ambulatory outcome were radiographically unstable. Compared with stable patients, unstable patients had a significant (p < 0.01) decrease in their ambulatory ability. There was a clear correlation between the degree of listhesis and postoperative ambulatory status (p < 0.01). The unstable patients with a poor ambulatory outcome followed one of three clinical courses: improvement with later deterioration, improvement with a plateau at a poor functional level, or failure to improve from a poor functional level. In conclusion, (a) although instability did not necessarily preclude a good outcome, a poor ambulatory outcome was always associated with instability; (b) laminectomy can effectively ameliorate the symptoms of lumbar stenosis; however, there is a subset of patients in whom laminectomy is associated with instability and a poor clinical course.

Adult↗

Nutritional supply to the cauda equina in lumbar adhesive arachnoiditis in rats.

Laminectomy-induced cauda equina adhesion has been proved by rat experiments and postoperative serial MRI in humans. A degenerative change of the cauda equina has been proved when cauda equina adhesion has been prolonged. Since it has not been reported how the nutritional supply is changed in such a condition, we evaluated the glucose supply to the adhered cauda equina in rats. Wistar rats were divided into the following three groups: the control group which received no operation, the laminectomy group which underwent L5-L6 laminectomy only, and the koalin group which received 5 mg of kaolin on the dorsal extradural space following L5-L6 laminectomy. Based on 3H-methyl-glucose uptake study, we analyzed (1) glucose transport from the intraneural vessels to the nerve tissue, and (2) glucose transport from the cerebrospinal fluid to the nerve tissue. We evaluated the relation between the severity of cauda equina adhesion and 3H uptake into the cauda equina. Cauda equina adhesion was observed in 2 of 12 rats in the control group, in 3 of 12 rats in the laminectomy group, and in 18 of 20 rats in the kaolin group. In the 3H-methyl-glucose uptake study, at 12 weeks the glucose transport to the cauda equina from the vessels increased by 44%, and that from the cerebrospinal fluid decreased by 64% in the kaolin group compared with the control group. In the condition of complete cauda equina adhesion, the glucose transport to the cauda equina from the vessels increased by 53% and that from the cerebrospinal fluid remarkably decreased by 72% compared with the normal cauda equina. Considering the greater nutritional importance of the cerebrospinal fluid in the cauda equina, it is most likely that the impairment of nutritional supply to adhered cauda equina may lead to eventual neural degeneration.

Animal Nutritional Physiological Phenomena↗

Neuroprotective effects of ebselen on experimental spinal cord injury in rats.

Spinal cord injury (SCI) results in rapid and significant oxidative stress. This study was aimed to investigate the possible beneficial effects of Ebselen in comparison with Methylprednisolone in experimental SCI. Thirty six Wistar albino rats (200-250 g) were divided in to six groups; A (control), B (only laminectomy), C (Trauma; laminectomy + spinal trauma), D (Placebo group; laminectomy + spinal trauma + serum physiologic), E (Methylprednisolone group; laminectomy + spinal trauma + Methylprednisolone treated), F (Ebselen group; laminectomy + spinal trauma + Ebselen treated), containing 6 rats each. Spinal cord injury (SCI) was performed by placement of an aneurysm clip, extradurally at the level of T11-12. After this application, group A, B and C were not treated with any drug. Group D received 1 ml serum physiologic. Group E received 30 mg/kg Methylprednisolone and, Group F received 10 mg/kg Ebselen intraperitoneally (i.p.). Rats were neurologically examined 24 h after trauma and spinal cord tissue samples had been harvested for both biochemical and histopathological evaluation. All rats were paraplegic after SCI except the ones in group A and B. Neurological scores were not different in traumatized rats than that of non-traumatized ones. SCI significantly increased spinal cord tissue malondialdehyde (MDA) and protein carbonyl (PC) levels and also decreased superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) enzyme activities compared to control. Methylprednisolone and Ebselen treatment decreased tissue MDA and PC levels and prevented inhibition of the enzymes SOD, GSH-Px and CAT in the tissues. However, the best results were obtained with Ebselen. In groups C and D, the neurons of the spinal cord tissue became extensively dark and degenerated with picnotic nuclei. The morphology of neurons in groups E and F were very well protected, but not as good as the control group. The number of neurons in the spinal cord tissues of the groups C and D were significantly less than the groups A, B, E and F. We concluded that the use of Ebselen treatment might have potential benefits in spinal cord tissue damage on clinical grounds.

Animals↗

5-year reoperation rates after different types of lumbar spine surgery.

STUDY DESIGN: Population-based cohort study of Washington State patients who underwent lumbar spine surgery for degenerative conditions in 1988. OBJECTIVES: To compare complications and reoperation rates during the 5-year period after surgery between patients who have undergone lumbar spine fusion surgery and those who have undergone laminectomy or discectomy alone. SUMMARY OF BACKGROUND DATA: Spinal fusion is associated with wider surgical exposure, more extensive dissection, and longer operative times than lumbar surgery without fusion, and previous studies have shown higher complication rates and hospital charges associated with these more complex procedures. In elderly patients, spinal fusion operations were associated with higher mortality rates than laminectomy or discectomy alone, and reoperation rates were not lower. In the current study, reoperations, mortality, and complications following lumbar spine surgery were examined for the general population. METHODS: A statewide hospital discharge database was used to identify all Washington patients who underwent spine surgery in 1988 and to determine the rate of reoperation during the subsequent 5 years. Administrative records also were used to identify complications, mortality, and hospital charges associated with the operations. Unadjusted complication and reoperation rates for the groups were compared using chi-square statistics. Adjusted rates were compared using logistic regression and proportional hazards (Cox) regression after controlling for age, gender, prior spine surgery, diagnosis, comorbidity, type of surgery, and coverage by Workers' Compensation. RESULTS: Of 6376 patients who underwent lumbar surgery for degenerative conditions in Washington in 1988, 1041 (16%) had operations involving spine fusion. Diagnoses of degenerative disc disease or possible instability were more frequent among patients undergoing fusion surgery, whereas herniated discs were more frequent among those undergoing discectomy or laminectomy alone. Complications were recorded in 18% of fusion patients and 7% of nonfusion patients (P < 0.01), but mortality rates did not differ. Unadjusted reoperation rates over the 5-year period were greater for patients who underwent fusion than for patients who underwent nonfusion surgery (18% vs. 15%, respectively), but after adjustment for baseline characteristics, fusion patients had only a slightly greater (and nonsignificant) risk of reoperation (relative risk 1.1, confidence interval .9-1.3). CONCLUSION: As in previous studies, complications in the current study occurred more frequently among patients who underwent lumbar spine fusion than among those who underwent laminectomy or discectomy alone. Reoperations were at least as frequent after fusion, but the authors could not assess treatment efficacy in terms of pain relief or improved function. Although the characteristics of patients undergoing fusion differed from those undergoing a laminectomy or discectomy alone, there appeared to be sufficient overlap in the clinical populations to warrant closer scrutiny of the safety, efficacy, and indications for spinal fusions, preferably in randomized trials.

Adult↗

Effects of prostaglandin E1, melatonin, and oxytetracycline on lipid peroxidation, antioxidant defense system, paraoxonase (PON1) activities, and homocysteine levels in an animal model of spinal cord injury.

STUDY DESIGN: Investigation of the effects of prostaglandin E1, melatonin, and oxytetracycline on lipid peroxidation, antioxidant and paraoxonase activities, and homocysteine levels in an experimental model of spinal cord injury. OBJECTIVES: To determine the antioxidant efficacy of prostaglandin E1, melatonin, and oxytetracycline and whether paraoxonase and homocysteine can be used as monitoring parameters in the acute oxidative stress of spinal cord injury. SUMMARY OF BACKGROUND DATA: Melatonin has been found useful in spinal cord injury in previous studies. No study exists investigating the effects of melatonin, prostaglandin E1, and oxytetracycline as well as the response type of paraoxonase enzyme and homocysteine levels in the acute oxidative stress of spinal cord injury. METHODS: Sixty-three male albino Wistar rats were anesthetized with 400 mg/kg chloral hydrate and divided into 5 groups. The G1 (n = 7) control group provided the baseline levels. G2-G5 underwent T3-T6 total laminectomies and spinal cord injuries by clip compression at the T4-T5 levels. Medications were applied to G3-G5 right after clip compression. Hence, G2 constituted laminectomy + injury, G3 laminectomy + injury + prostaglandin E1; G4 laminectomy + injury + melatonin, and G5 laminectomy + injury + oxytetracycline groups. Animals were decapitated either the first or fourth hour after injury. Spinal cord tissue and blood malonyldialdehyde and plasma homocysteine levels, plasma glutathione peroxidase, superoxide dismutase, paraoxonase activities were assayed. The SPSS 9.0 program was used for statistical analysis and graphics. Intergroup comparisons were made by Bonferroni corrected Mann Whitney U test (P < 0.025) and intragroups comparisons by Wilcoxon Rank test (P < 0.03). RESULTS: In injury groups, plasma homocysteine levels decreased and paraoxonase activities increased as erythrocyte superoxide dismutase levels and plasma glutathione peroxidase activities decreased in parallel to increases of tissue and blood malonyldialdehyde levels. These alterations were relatively suppressed by prostaglandin E1, melatonin, and oxytetracycline administrations in varying degrees. Melatonin was the most powerful agent, particularly at the fourth hour. Oxytetracycline was also effective, both at the first and fourth hour. Prostaglandin E1 was effective in comparison to injury group, but not as much as melatonin and oxytetracycline. CONCLUSIONS: Melatonin and oxytetracycline are effective in preventing lipid peroxidation in spinal cord injury. Paraoxonase and homocysteine can be used in monitoring the antioxidant defense system as well as superoxide dismutase and plasma glutathione peroxidase, both in injury and medicated groups.

Acute Disease↗

Characterization of pain and pharmacologic responses in an animal model of lumbar adhesive arachnoiditis.

STUDY DESIGN: The study used a small animal laminectomy model with kaolin to investigate the relationship of cauda equina pathology to pain, and the effects of systemic and intrathecal drugs to reduce pain. OBJECTIVE: To determine if higher amounts of cauda equina adhesions produce increased pain-related behavior following laminectomy and epidural kaolin application. SUMMARY OF BACKGROUND DATA: Clinically, the relationship of cauda equina pathology to pain is controversial. An established animal model produces cauda equina adhesions. The correlation of this anatomic pathology with pain-related behavior has not been examined. METHODS: A laminectomy was performed in Sprague-Dawley rats at the L5-L6 vertebrae, and kaolin was applied extradurally. Sham control animals had vertebrae exposed but no laminectomy/kaolin. Animals were monitored for pain-related behavior using vocalization in response to straight leg raising. Histology was performed at 6 weeks postoperatively. Laminectomy animals were tested with systemic or intrathecal drugs to reduce straight leg raising vocalizations. RESULTS: In laminectomy animals, the pain response developed over 6 weeks, with vocalizations increasing from 0 to 1.65, out of 5 leg lifts. Cauda equina clumping was related to pain severity. Systemic morphine 3 mg/kg, but not 1 mg/kg, decreased vocalization to straight leg raising. Intrathecal morphine at 30 nmol, but not 10 nmol, gabapentin at 60 nmol, but not 20 nmol, decreased vocalizations. Intrathecal clonidine up to 90 nmol did not reduce vocalization. CONCLUSIONS: An animal model of adhesive lumbar arachnoiditis yields a quantifiable pain-related response that can be used to evaluate the effects of various analgesic interventions.

Amines↗

Metastatic epidural spinal cord compression. Results of treatment and survival.

All medical records of patients treated for metastatic compression of the spinal cord or cauda equina in the eastern part of Denmark from 1979 through 1985 were reviewed. With regard to treatment response and survival, 345 patients could be evaluated. Carcinoma of the lung (19%), prostate (18%), breast (13%), and kidney (10%) were the most frequent primary malignancies causing spinal compression. The outcome of treatment depended primarily on the patients' condition at the time of diagnosis: 79% of the patients who were able to walk before the treatment remained ambulatory, whereas only 21% of the nonambulatory paraplegic patients and 6% of the paralytic patients regained walking ability. Patients treated with laminectomy followed by radiotherapy seemed to respond better than patients treated with radiotherapy or laminectomy alone, but when the patients' pretreatment motor function was taken into account no significant difference was found between the three forms of treatment. In the subgroup of nonambulatory patients, however, a significantly better restoration of gait was observed in patients treated with the combination of laminectomy and radiotherapy than in patients treated with radiotherapy alone. A longer survival in the group treated with the combination of laminectomy and radiotherapy may reflect that these patients were in a lower stage of disease and thus had a better potential of regaining motor function. The results call for prospective randomized studies.

Adolescent↗