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At least 19 recordsLinked to original sources
PubMed2004

A preclinical post laminectomy rat model mimics the human post laminectomy syndrome.

Chronic low back pain with sciatica complicating post laminectomy surgery is poorly understood. It is likely that some aspects of persistent pain of the syndrome results from spinal facilitation in which there is lowering of pain excitation levels. A small animal preclinical model is needed that mimics the clinical condition to permit detailed studies of the underlying altered neurochemistry of the sensory pathways. We propose herein a rat laminectomy model containing the elements required for study of the neurobiology of the condition. The model consists of a surgical laminectomy that includes L5 spinal nerve manipulation and disc injury, elements necessarily employed in human disc herniation surgery. At 8 weeks post laminectomy the proposed model demonstrates paraspinous muscle spasm, tail contracture, behavioral pain behavior, tactile allodynia, epidural and nerve root scarring, and nerve root adherence by scar to the underlying disc and adjacent pedicle. Two underlying pain facilitation states are invoked in the clinical condition: (1) an inflammatory state required to achieve wound healing; and (2) a nerve injury state resulting from nerve manipulation and subsequent epidural scarring, spinal nerve scarring, and spinal nerve tethering to the adjacent disc and pedicle. Both pain facilitation states are active in the model.

Analysis of Variance↗
PubMed1987

The prevention of adhesions after laminectomy. Adverse results of Zenoderm implantations into laminectomy sites in rabbits.

Zenoderm (Ethicon Ltd., Edinburgh, Scotland) is porcine skin dermis specially treated so as to be weakly antigenic when implanted. Its use as an extradural spinal and nerve root membrane to reduce postoperative adhesions after laminectomy was tested in 22 rabbits with laminectomy in the second and fourth lumbar vertebra. The sites were reviewed histologically two to 36 weeks after operation. Histologic sections showed that Zenoderm was initially surrounded by hematoma that organized into fibrous tissue and, later, bone. When Zenoderm was placed immediately adjacent to the dura, dense adhesions formed, which were slower to resolve than those in the control sites. The rate of Zenoderm resorption was variable. In general, Zenoderm did not excite excessive fibrous tissue formation and was slowly replaced by bone. Contrary to the experience of others, it was unusual to find adhesions between the laminectomy site, and the dura began disappearing after six to nine weeks. In rabbits, Zenoderm is unlikely to prevent adhesions forming after lumbar disc surgery. The resorption rate is variable, and laminectomy sites are unsuitable for the investigation of material for the prevention of spinal dural adhesions.

Absorption↗
PubMed1977

Posterior decompression for myelopathy due to cervical spondylosis: laminectomy alone versus laminectomy with dentate ligament section.

In summary we have reviewed some of the studies and theories regarding the role of the dentate ligaments in cervical spondylosis and myelopathy and the logic which has been proposed either for or against their transection in the surgical treatment of this disease. A review of our own series of patients shows no significant increased morbidity in patients undergoing decompressive laminectomy, dentate ligament section, and dural graft as compared to laminectomy alone for treatment of myelopathy due to cervical spondylosis. Of equal importance is the fact that we could demonstrate no superiority in terms of neurological benefit between these two types of operative therapy. However, intradural inspection carried out as a matter of routine did reveal unexpected midline disk protrusions in two cases, the removal of which allowed the patients to do better than might have been expected from laminectomy alone. These findings lead us to conclude that intradural exploration is always indicated if there exists any doubt as to the nature of the basic pathological process. Also there has been presented some experimental evidence to support division of the dentate ligaments if an unresectable anterior lying mass is found.

Cervical Vertebrae↗
PubMed2003

Biomechanical comparison of facet-sparing laminectomy and Christmas tree laminectomy.

OBJECT: The authors compared differences in biomechanical stability between two decompressive laminectomy techniques for treating lumbar stenosis. A Christmas tree laminectomy (CTL), in which bilateral facetectomies and foraminotomies are performed, was compared with facet-sparing laminectomy (FSL), in which the facets are undercut but not resected. Spinal instability was assessed immediately postoperatively and again after discectomy to model long-term degeneration. METHODS: Sixteen motion segments obtained from five human cadaveric lumbar specimens were studied in vitro by conducting nondestructive flexibility tests. Specimens were tested intact, after FSL or CTL, and again after discectomy. Nonconstraining torques (< or = 5 Nm) were applied to induce flexion, extension, axial rotation, and lateral bending; strings and pulleys were used while vertebral angles were measured. Anteroposterior translation in response to shear loading (< or = 100 N) was also measured. Angular motion, shear motion, and sagittal-plane axes of rotation were compared to evaluate stability. Compared with the intact condition, CTL-treated specimens had significantly larger increases in angular motion during flexion, lateral bending, and axial rotation than their FSL-treated counterparts (p < 0.05, nonpaired Student t-tests). Subsequent discectomy caused greater increases in motion in the CTL group. Axes of rotation shifted less from their normal positions after FSL than after CTL. CONCLUSIONS: This study provides objective evidence that the treatment of lumbar stenosis with FSL induces less biomechanical instability and alters kinematics less than FSL. These findings support the use of the FSL in treating lumbar stenosis.

Biomechanical Phenomena↗
PubMed1988

Heparinized materials for control of the formation of the laminectomy membrane in experimental laminectomies in dogs.

This study examined the efficacy of heparinized biodegradable materials in the prevention of post-laminectomy scar formation using a canine system. Six-level noncontiguous laminectomies were performed on five adult canines. Exposed dura at each level was covered with the following: (1) nothing (control); (2) fat; (3) fat and autogeneic bone; (4) heparinized Avitene; (5) heparinized Surgicel; or (6) heparinized collagen gel. Canines were killed 16 weeks postoperatively and histologic specimens examined. Fibrous adhesions were abundant at Site 1 (control). Free fat grafts were well preserved and did not permit adhesions at Sites 2 and 3. None of the heparinized materials was as effective as fat in controlling scar formation. Overlying bone at Site 3 did not alter the quality of a free fat graft placed over the dura, a point possibly significant for laminectomies followed by fusion.

Adipose Tissue↗
PubMed1981

Bupivacaine infiltration after lumbar laminectomy. Local infiltration in the control of early postoperative lumbar laminectomy pain.

This is a report of a double-bind controlled trial to test the hypothesis that peroperative local infiltration of the wound of lumbar laminectomy with bupivacaine produces a significant reduction in postoperative back pain. No such effect was demonstrated when the linear analogue was used to record the patients' subjective response to pain. It is suggested that this treatment is not indicated as a routine method.

Adult↗
PubMed2003

A histologic and functional study on cauda equina adhesion induced by multiple level laminectomy.

STUDY DESIGN: A histologic and functional study on cauda equina adhesion induced by multiple-level laminectomy was performed using rats. OBJECTIVE: To assess the relation between the extent of laminectomy and histologic and functional changes of the cauda equina induced by laminectomy. SUMMARY OF BACKGROUND DATA: It has been demonstrated that laminectomies may induce cauda equina adhesion, transiently or permanently. However, the relation between the extent of laminectomy and histologic and functional changes of the cauda equina induced by laminectomy is still unclear. METHODS: Sprague-Dawley rats (250-300 g) were used. They were divided into four groups: no-laminectomy group (n = 5) and single, double, and triple level laminectomy groups (n = 20, respectively). At 24 hours and 1, 3, and 6 weeks after laminectomy, rats in each group were killed, and specimens were obtained from L4 to L6. The histologic changes were assessed using the classification of Yamagami. Walking durations on treadmill test and ascending spinal nerve-evoked potential were assessed in laminectomy groups before laminectomy, then weekly for 1 to 6 weeks after laminectomy. RESULTS: With the greater extent of laminectomy, the decrease in cauda equina adhesions was more delayed. There was no difference in walking durations and ascending spinal nerve-evoked potential between pre- and postlaminectomy. CONCLUSIONS: The extent of laminectomy was related to recovery time of induced cauda equina adhesion. However, a delay in recovery from cauda equina adhesion may not produce a recognizable delay in recovery from clinical symptoms.

Animals↗
PubMed1999

[Postoperative, appositional ossifications after lumbar laminectomy].

QUESTION: Post-laminectomy segmental hypermobility as well as appositional ossification were suggested by many authors to contribute to the unsatisfactory long-term results of laminectomy. The aim of this study was to find out whether segmental instability, among other factors, influences the degree of appositional ossification following laminectomy. METHODS: 55 out of 72 patients operated upon by laminectomy or hemilaminectomy for degenerative lumbar spinal stenosis were examined by radiography after an average follow-up period of 5.2 years. Appositional ossification at the site of surgery was evaluated in relation to lumbar instability, the number of segments undergoing laminectomy, and whether simultaneous fusion was done. Instability was determined by measuring angulation and translation using lateral flexion and extension views of the lumbar spine, whereas new-bone formation was best evaluated on antero-posterior radiographs. RESULTS: 94% of the patients had appositional ossification at the site of laminectomy. Patients undergoing simultaneous fusion with laminectomy had a significantly lower amount of appositional ossification compared to patients undergoing laminectomy without segmental fusion. Radiographically measured segmental instability, the number of segments undergoing laminectomy, age, and sex of the patients did not influence the extent of ossification. CONCLUSIONS: Postoperative appositional ossification at the posterior site of resection are seen regularly following laminectomy. The extent of appositional ossification does correlate with lumbar fusions, but does not correlate with the extent of radiographically measured lumbar instability, the number of segments undergoing laminectomy, or the age and sex of the patients. CLINICAL RELEVANCE: Simultaneous lumbar fusion with laminectomy is proved to be associated with less appositional ossification. Therefore lumbar fusion should be considered when planning surgery for spinal stenosis.

Adult↗
PubMed1991

Cervical laminectomy and dentate ligament section for cervical spondylotic myelopathy.

Seventy-five patients who underwent surgical treatment for cervical spondylotic myelopathy were evaluated with respect to the operative procedure performed and their outcome. Forty patients underwent a laminectomy plus dentate ligament section (DLS), 18 underwent laminectomy alone, and 17 underwent an anterior cervical decompression and fusion (ACDF). The patients were evaluated postoperatively for both stability and for neurologic outcome using a modification of the Japanese Orthopaedic Association Assessment Scale. Functional improvement occurred in all but one patient in the laminectomy plus DLS group. The average improvement was 3.1 +/- 1.5 points in this group; whereas the average improvement in the laminectomy and the ACDF groups was 2.7 +/- 2.0 and 3.0 +/- 2.0 points respectively. All of the patients who improved substantially (greater than or equal to 6 points) in the laminectomy plus DLS and the laminectomy alone groups had normal cervical spine contours (lordosis). The remainder had either a normal lordosis or no curve (no kyphosis or lordosis). All patients in the ACDF group had either a straight spine or a cervical kyphosis. These factors implicate spine curvature, in addition to choice of operation, as factors which are important in outcome determination. No problems with instability occurred in either the laminectomy or the laminectomy plus DLS group. Two patients incurred problems with stability in the ACDF group. Both required reoperation. In addition, four patients in this group who initially improved, subsequently deteriorated. Six patients in the laminectomy plus DLS group had a several day febrile episode related to an aseptic meningitis process. Laminectomy plus DLS is a safe and efficacious alternative to laminectomy for the treatment of cervical spondylotic myelopathy. The data presented here suggests that myelopathic patients with a cervical kyphosis are best treated with an ACDF and that patients with a normal cervical lordosis are best treated with a posterior approach. Although some selected patients may benefit from DLS, no criteria are available which differentiate this small subset of patients.

Adult↗
PubMed1978

Effects of laminectomy on spinal cord blood flow.

The effect of a one-segment (L-2) laminectomy on spinal cord blood flow (SCBF) was determined by the reference sample method using isotope-labeled microspheres. The SCBF was measured before laminectomy (control) and at 15 minutes postlaminectomy with the dura exposed (Series 1), 1 hour postlaminectomy with the laminectomy site closed (Series 2), 24 hours postlaminectomy with the laminectomy site closed (Series 3), and 24 hours postlaminectomy with the dura exposed (Series 4). With the laminectomy site open, SCBF was significantly depressed (22% to 45%) along the entire length of the spinal cord at 15 minutes postlaminectomy. At 1 hour postlaminectomy (with the laminectomy site closed), SCBF approached control values, although areas with significantly lowered flow were still observed in all portions of the spinal cord. By 24 hours postlaminectomy, SCBF had returned to prelaminectomy levels. However, if within 1 hour preceding the 24-hour SCBF measurement, the laminectomy site was reopened, SCBF tended to fall at and caudad to the laminectomy site. These data indicate that laminectomy can cause a significant decline in SCBF. At the present time, the mechanism(s) for this laminectomy-induced depression of SCBF are unknown, although a temperature-induced vasoconstriction is suspected.

Animals↗
PubMed1992

A 1- to 4-year follow-up review of treatment of sciatica using chemonucleolysis or laminectomy.

To help clarify the comparative effects of chemonucleolysis and discectomy, the author studied 178 consecutive patients with sciatica who did not respond to conservative treatment. None had previously undergone laminectomy or chemonucleolysis or had spinal stenosis. All received postmyelography computerized tomography (CT) and, if the radiological interpretation was that of an extruded migrated disc, a laminectomy was performed; otherwise, the patient was given a choice of the two procedures. Of the 178 patients, 106 underwent chemonucleolysis and 72 laminectomy. Workers' compensation was being paid to 21.6% of the chemonucleolysis patients and 20.8% of the laminectomy patients. Postoperatively, substantial improvement was noted in 82.7% of the chemonucleolysis patients and 92.5% of the laminectomy patients at 6 weeks and in 92.8% of the chemonucleolysis patients and 89.7% of the laminectomy patients at 6 months. The majority of patients in both groups had improved neurological signs. Follow-up questionnaires at 1 to 4 years postoperatively revealed an overall success rate of 86.5% for chemonucleolysis patients and 83.8% for laminectomy patients. In patients not receiving workers' compensation, 90.1% of the chemonucleolysis patients and 88.6% of the laminectomy patients had a successful outcome; in those receiving workers' compensation, 69.6% of the chemonucleolysis patients and 60.0% of the laminectomy patients had a successful outcome. No statistically significant differences in improvement rate in neurological symptoms or signs were identified between the two procedures. Overall, 85.1% of the chemonucleolysis patients and 78.5% of the laminectomy patients were employed at follow-up review. To achieve optimum results and eliminate noncandidates for chemonucleolysis, routine use of postmyelography CT is recommended. When properly used, chymopapain chemonucleolysis is an acceptable alternative to surgical discectomy.

Adult↗
PubMed1995

Biomechanical alterations induced by multilevel cervical laminectomy.

STUDY DESIGN: The biomechanical responses of the cervical spine undergoing a combined loading vector within the physiologic range and after multilevel laminectomy were evaluated. The experimental conditions were designed to more closely replicate the typical clinical situation than accomplished by previous studies. OBJECTIVE: To determine the biomechanical alterations induced by multilevel cervical spine laminectomy using an in vitro model. SUMMARY OF BACKGROUND DATA: The few previous laboratory studies concerned with the effects of cervical laminectomy have generally indicated a lack of significant change in strength or flexibility induced by the procedure. These studies have been limited by a variety of factors, including the use of pure loads under low physiologic loading conditions, restriction of the laminectomy to one or two segments, and the evaluation of a small number of specimens. METHODS: Twelve fresh human cadaver cervical spine segments from C2-T1 were used. A custom-designed fixture was attached to the proximal end of the specimen to apply a flexion-compression load. Retroreflective targets were positioned in bony landmarks for localized temporal kinematics of the entire cervical column. Testing was performed before (intact) and after a three-level (C4-C6) laminectomy, and data regarding the force, displacement, and kinematics at every level of the column were obtained. RESULTS: The mean stiffness of the intact cervical column was significantly greater (P < 0.05) than the mean stiffness for the laminectomized specimen. Sagittal rotation angle had significant (P < 0.05) differences between intact (3.6 degrees) and laminectomy (8.0 degrees). Laminectomized specimens consistently responded with higher rotations compared with the intact specimen at every cervical spine level. CONCLUSION: Multilevel cervical laminectomy induces significant increases in total column flexibility associated with increased segmental flexural sagittal rotations. These motion changes were generalized with a tendency to show the greatest change at the lower level of laminectomy. Such biomechanical changes may constitute part of the underlying basis for failure of laminectomy to offer sustained good therapeutic results of the myelopathy associated with cervical stenosis and cervical spondyloarthropathy.

Adult↗
PubMed1995

Chemonucleolysis versus laminectomy. A cohort comparison of effectiveness and charges.

STUDY DESIGN: A prospective cohort study was done comparing 100 consecutive chemonucleolysis patients with 100 consecutive laminectomy patients. OBJECTIVES: The effectiveness and cost of chymopapain chemonucleolysis was compared with that of laminectomy to manage herniated lumbar discs. SUMMARY OF BACKGROUND DATA: Although the efficacy of chemonucleolysis has been established, controversy regarding the relative benefits of chemonucleolysis and laminectomy continues to arise. The relative cost-effectiveness of the two procedures has not been evaluated previously in a cohort study. METHODS: Patients in both treatment groups were of comparable age, height and weight, and worker's compensation status. Patients with migrated disc were not considered for chemonucleolysis. Improvement in pain, paresthesia, straight-leg raising, reflexes, motor loss, and sensory function, self-reported overall improvement, ability to maintain employment, and charge of treatment were used to measure treatment success. RESULTS: Clinical assessment after 6 weeks showed 92% of laminectomy patients compared with 82% of chemonucleolysis patients compared with 82% of chemonucleolysis patients had successful results (P = 0.058). Chemonucleolysis patients had greater improvement in numbness (P = 0.014) and sensory and motor functions (P = 0.002). After 6 months, 88% of chemonucleolysis patients and 85% of laminectomy patients had successful results, with a greater improvement in sensory status of chemonucleolysis patients and 82% of laminectomy patients had successful results, and more chemonucleolysis patients than laminectomy results, the average charge savings for chemonucleolysis patients was +5365 when chemonucleolysis was performed instead of laminectomy. CONCLUSION: This study shows that chemonucleolysis is an effective as laminectomy in appropriately selected patients but at lower charge and can contribute substantially to reducing short-and long-term health costs.

Adolescent↗
PubMed1987

Thoracolumbosacral laminectomy in achondroplasia: long-term results in 22 patients.

Neurologic problems caused by vertebral stenosis in the thoracolumbosacral (TLS) region are common in achondroplasia. Surgical decompression by means of laminectomy is recommended often, but its long-term results have not been assessed. We reviewed the clinical history of 22 achondroplastic patients who had at least one TLS laminectomy performed before 1981. Symptoms predated the first TLS laminectomy by a mean of 2.3 years (range 0.1-17 years). Preoperatively, 91% of patients had motor function impairment, 86% had sensory dysfunction, 86% had neurogenic claudication, 77% had radicular pain, 59% had symptomatic bladder dysfunction, and 32% had fecal incontinence. Only upper motor neurons were affected in 45%, only lower motor neurons in 27%, and both in 27%. Follow-up after the first TLS laminectomy averaged 8 years. Of the 20 patients who initially improved neurologically, 12 had functional improvement for more than 5 years. However, 11 of these 12 subsequently regressed and 10 had additional laminectomies. Long-term neurologic and functional improvement was associated with both a short duration of symptoms preoperatively and absence of cervical stenosis. Because of hypertrophic scarring, 9 patients developed compression at the site of the initial TLS laminectomy and required re-operation 6.4 years (range 1-11 years) later. We conclude that TLS laminectomy is an effective treatment for spinal stenosis if performed early in the course of the neurologic syndrome. However, some patients have, or later develop, compression adjacent to the myelographic site of stenosis, and some develop hypertrophic scarring at the site of initial decompression. We therefore suggest that the first TLS laminectomy extend (1) 3 levels cephalad to the myelographic block, (2) at least to S2, and (3) laterally at least to the facets.

Achondroplasia↗
PubMed2003

Influence of graded facetectomy and laminectomy on spinal biomechanics.

Facetectomy and laminectomy are techniques for decompressing lumbosacral spinal stenosis. Resections of posterior bony or ligamentous parts normally lead to a decrease in stability. The degree of instability depends on the extent of resection, the loading situation and the condition of the intervertebral discs. The correlation between these parameters is not well understood. In order to investigate how these parameters relate to one another, a three-dimensional, non-linear finite element model of the lumbosacral spine was created. Intersegmental rotations, intradiscal pressures, stresses, strains and forces in the facet joints were calculated while simulating an intact spine as well as different extents of resection (left and bilateral hemifacetectomy, hemilaminectomy and bilateral laminectomy, two-level laminectomy), disc conditions (intact and degenerated) and loading situations (pure moment loads, standing and forward bending). The results of the modelling showed that a unilateral hemifacetectomy increases intersegmental rotation for the loading situation of axial rotation. Expanding the resection to bilateral hemifacetectomy increases intersegmental rotation even more, while further resection up to a bilateral laminectomy has only a minor additional effect. Hemilaminectomy and laminectomy only differ in their effect for ventriflexion and muscle-supported forward bending. Two-level laminectomy increases the intersegmental rotation only for standing. Degenerated discs result in smaller intersegmental rotations and higher disc stresses at the respective levels. Decompression procedures affect the examined biomechanical parameters less markedly in degenerated than in intact discs. Resection of posterior bony or ligamentous elements has a stronger influence on the amount than on the distribution of stresses and deformations in a disc. It has only a minor effect on the biomechanical behaviour of the adjacent region. Spinal stability is decreased after a laminectomy for forward bending, and after a two-level laminectomy for standing. For axial rotation, spinal stability is decreased even after a hemifacetectomy. Patients should therefore avoid excessive axial rotation after such a treatment.

Biomechanical Phenomena↗
PubMedDate not supplied

Skip laminectomy--a new treatment for cervical spondylotic myelopathy, preserving bilateral muscular attachments to the spinous processes: a preliminary report.

BACKGROUND CONTEXT: Techniques in current use for expansive laminoplasty operations (ELAP) on the cervical spine damage the extensor mechanisms, resulting in restriction of neck motion, loss of lordosis and persistent axial pains. PURPOSE: This article introduces a new surgical technique called skip laminectomy, which reduces morbidity after decompression of the cervical spinal canal. STUDY DESIGN/SETTING: A prospective study is presented of all patients with multilevel cervical spondylotic myelopathy (CSM), treated by this new procedure between December 1998 and March 2000. PATIENT SAMPLE: Since December 1998, 61 patients with CSM have undergone the procedure, of whom 24 (13 men and 11 women) were selected for this study. Follow-up periods ranged from 12 to 25 months, with an average of 18 months. Average age at operation was 69 years (range, 50 to 82 years). Eighteen patients with CSM on whom C3-C7 open-door laminoplasties had been performed by the author before 1998 were selected as controls for study of postoperative atrophy of the deep extensor cervical muscles. There were 11 men and 7 women, average age 67 years (range, 45 to 81). OUTCOME MEASURES: Axial symptoms and Japanese Orthopaedic Association (JOA) scores were recorded. Pre- and postoperative ranges of neck motion were measured on lateral flexion and extension radiographs. Pre- and postoperative cervical curvature indexes were calculated according to Ishihara's method. For quantitative analysis of damage to the posterior cervical muscles, atrophy rates were calculated from cross-sectional areas of the deep extensor muscles on the pre- and postoperative axial magnetic resonance imaging. METHODS: In skip laminectomy, standard laminectomies are performed at selected levels, combined with partial laminectomies of the cephalad halves of laminae at other selected levels, where the muscular attachments to the spinous processes are left undisturbed. Instead of a standard laminectomy, an interlaminar decompression can be performed at levels where the anterior spinal cord compression is insignificant. It is accomplished by simply removing the cephalad half of the inferior lamina and ligamentum flavum without detaching the semispinalis cervicis and multifidus muscles from the adjacent spinous processes. RESULTS: Using JOA scores, the average recovery rate was 61.0%. None of the patients complained of persistent axial symptoms. The postoperative range of flexion-extension motion averaged 97% of the preoperative measures. The cervical curvature index was reduced in 1 of the 24 patients. The atrophy rate of the deep extensor muscles after skip laminectomy was 20% of that seen after open-door laminoplasty. CONCLUSIONS: Skip laminectomy for cervical spinal canal decompression is less invasive than conventional laminectomy and ELAP. It is effective in preventing postoperative problems, such as persistent axial symptoms, restriction of neck motion and loss of cervical lordosis.

Aged↗