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PubMed2000

Laminectomy versus percutaneous electrode placement for spinal cord stimulation.

OBJECTIVE: The purpose of this study was to compare the long-term effectiveness of spinal cord stimulation using laminectomy-style electrodes versus that using percutaneously implanted electrodes. METHODS: Forty-one patients underwent an initial trial period of spinal cord stimulation with temporary electrodes at Duke Medical Center between December 1992 and January 1998. A permanent system was implanted if trial stimulation reduced the patient's pain by more than 50%. Median long-term follow-up after permanent electrode placement was 34 months (range, 6-66 mo). Severity of pain was determined postoperatively by a disinterested third party using a visual analog scale and a modified outcome scale. RESULTS: Twenty-seven (66%) of the 41 patients participating in the trial had permanent electrodes placed. Visual analog scores decreased an average of 4.6 among patients in whom electrodes were placed via laminectomy in the thoracic region (two-tailed t test, P < 0.0001). Patients who underwent percutaneous placement of thoracic electrodes had an average decrease of 3.1 in their visual analog scores (two-tailed t test, P < 0.001). Electrodes placed through laminectomy furnished significantly greater long-term pain relief than did those placed percutaneously, as measured by a four-tier outcome grading scale (P = 0.02). CONCLUSION: Spinal cord stimulation is an effective treatment for chronic pain in the lower back and lower extremities that is refractory to conservative therapy. Electrodes placed via laminectomy in the thoracic region appear to be associated with significantly better long-term effectiveness than are electrodes placed percutaneously.

Adult↗
PubMedDate not supplied

Spinal deformity and instability after multilevel cervical laminectomy.

Sixty-four patients who had undergone multilevel cervical laminectomy were studied for postoperative spinal deformity and instability. Special attention was given to patients with cervical spondylosis (CS), ossification of the posterior longitudinal ligament (OPLL), and spinal cord tumors. Twenty-three (36%) of 64 patients showed postoperative changes in curvature type and 9 (14%) had developed spinal deformity (kyphotic or meandering-type curvature). In two juvenile patients, the deformity developed soon after operation and spinal fusion was required to prevent neurologic complications. In the adult cases, contrary to the hitherto accepted concept, long-term follow-up revealed the tendency of the deformity to develop more frequently in OPLL cases than in CS cases. Mobility of the cervical spine was reduced considerably after laminectomy, both in CS and OPLL cases. There was no adult patient who required further operation for severe deformity or instability after laminectomy. Extensive laminectomy, even including the C2 lamina, seemed to have no adverse effect on the stability of the cervical spine.

Cervical Vertebrae↗
PubMed1988

Comparison of the results of laminectomy and open-door laminoplasty for cervical spondylotic myeloradiculopathy and ossification of the posterior longitudinal ligament.

Laminectomy was performed on 14 patients with cervical radiculomyelopathy and ossification of the posterior longitudinal ligament (OPLL). Since 1978, simple open-door laminoplasties have been performed on 75 patients. A retrospective study was done to determine if there was any difference between the results of laminectomy and laminoplasty. Overall results of laminectomy were as follows: The preoperative Japanese Orthopaedic Association (JOA) score was 7.0 points and the postoperative score was 15.0 points. Overall results of laminoplasty were as follows: the preoperative JOA score was 7.0 points and the postoperative score was 15.0 points. The percentage improvement in laminectomy was 81.1%, and in laminoplasty was 81.4%. There was no significant difference in the results of these two procedures for the treatment of patients with cervical radiculomyelopathy and OPLL.

Adult↗
PubMed1995

Inhibition of epidural scar formation after lumbar laminectomy in the rat.

STUDY DESIGN: An animal model of laminectomy in rats was used to study scar tissue formation around the spinal cord. Dexamethasone, in controlled-release form, was tested in this system for its ability to decrease fibrous tissue formation. OBJECTIVES: The results were evaluated to determine whether dexamethasone in a biodegradable controlled-release vehicle could be used to limit scar tissue formation around the spinal cord after laminectomy. SUMMARY OF BACKGROUND DATA: Steroids can delay the formation of scar tissue. Continued treatment with dexamethasone results in various unacceptable side effects. Use of biodegradable controlled-release vehicles to deliver drugs may allow for prolonged low-dose treatment, concentrated at the surgical site, thereby avoiding side effects. METHODS: Forty-four Sprague Dawley rats underwent laminectomies and were treated with dexamethasone in one of two controlled-release vehicles or with vehicle alone. After 4 weeks, the rats were killed and histologic sections prepared from the spines were examined and graded by a pathologist. In addition, the dexamethasone preparations were introduced into Hunt-Schilling wound chambers, which were implanted in rats. Four weeks after implantation, the wound chambers were removed and the tissue inside was assayed for DNA and protein content. RESULTS: Dexamethasone acetate (Decadron, MSD, West Point, PA) significantly reduced the density of the scar tissue undermining the laminas. Steroids embedded in polymer did not change the scar formation in the back, but did decrease protein and DNA values in wound chamber tissues. CONCLUSIONS: Long-term release of small amounts of steroid from the polymer poly-carboxy-phenoxypropane does not appear to reduce scar at laminectomy sites but does decrease the protein:DNA ratio in wound chambers. In contrast, Decadron does not significantly alter the biochemistry of wound chamber tissue but does reduce scar in the back.

Animals↗
PubMed1996

Health outcome assessment before and after lumbar laminectomy for radiculopathy.

STUDY DESIGN: Forty-one patients undergoing lumbar laminectomy for radiculopathy resulting from herniated discs assessed their health status using a generic health outcome instrument (Medical Outcomes Study Short Form 36) before surgery and at an average of 2 years after surgery. OBJECTIVES: To assess whether lumbar laminectomy for herniated nucleus pulposus is a useful intervention when patients evaluate their own perception of health. SUMMARY OF BACKGROUND DATA: The medical Outcomes Study Short Form 36 has been used in multiple studies assessing various medical conditions. It is brief, generic, and reliable. Although surgical treatment for radiculopathy by lumbar laminectomy has been shown to be successful using specific criteria for patient selection and an algorithmic approach, the authors are not aware of any study using a patient-based health outcome assessment to evaluate the results of this type of surgery. METHODS: Forty-one patients (82% completed follow-up evaluation; average follow-up period, 2.08 years) completed Medical Outcomes Study Short Form 36 before and after surgery. Scores from before and after surgery were compared. RESULTS: Statistically significant improvements (P < 0.01) were seen in eight of the nine health scores comparing scores from before and after surgery at follow-up evaluation. These included physical function, social function, role function resulting from physical limitations, role function resulting from emotional limitations, mental health, vitality, pain, and perceived health change. No significant change was seen in the patients' health perception after surgery. CONCLUSIONS: This study shows that the patients' self-reported health outcomes after lumbar laminectomy correlate with the excellent results previously seen using physician-driven outcome measures in an appropriately selected population with radiculopathy. The excellent results shown here did not deteriorate with age (> 40 years compared with < 40 years) or with complications after surgery.

Case-Control Studies↗
PubMed1998

Spinal deformity and instability after multilevel cervical laminectomy for spondylotic myelopathy.

STUDY DESIGN: A retrospective radiographic and medical record analysis of 58 patients. OBJECTIVES: To describe the incidence and consequences of cervical spinal deformity and instability after multilevel laminectomy in adult patients with myelopathy caused by cervical spondylosis and to determine the usefulness of preoperative dynamic roentgenographic films in the prevention of postoperative destabilization. SUMMARY OF BACKGROUND DATA: Extensive cervical laminectomy has been widely used in the treatment of progressive myelopathy secondary to stenotic conditions. Complications of this procedure, including spinal instability, accelerated spondylotic changes, postoperative spinal deformity, and constriction of the dura mater by formation of extradural scar tissue formation have been recognized. However, the frequency of these complications is probably overestimated, and their effect on clinical outcome remains unknown. METHODS: Fifty-eight patients older than 30 years who underwent a laminectomy at more than three levels without fusion for myelopathy secondary to cervical spondylosis were reviewed retrospectively with an average follow-up of 3.6 years. Functional results were evaluated according to the Japanese Orthopaedic Association's scoring system. Lateral views in neutral position, in flexion, and in extension of the preoperative cervical roentgenograms were analyzed in comparison with the last follow-up films to identify the changes in the curvature of the cervical column, in the range of motion of the neck, and in the intervertebral angular mobility and anteroposterior displacement of the vertebral bodies and finally to quantify the incidence of spinal instability. RESULTS: In 18 patients (31%), postoperative changes in the type of cervical spine curvature developed. Fifteen patients (25%) had destabilization at one or more levels. Deformities of the cervical spine occurring after surgery do not appear to cause symptoms or neurologic abnormalities. Destabilization required repeat surgery in 3 patients. All the levels appearing to be destabilized on the postoperative films were hypermobile on the preoperative dynamic radiographs. Preoperative olisthesis Without hypermobility is not a factor of risk in postoperative destabilization. CONCLUSIONS: The use of preoperative dynamic radiographs should improve the selection of patients undergoing laminectomy for the treatment of multilevel cervical cord compression. Dynamic radiographs may also reinforce the need for such adjunctive procedures as fusion and instrumentation, to prevent postoperative destabilization. Preoperative olisthesis with hypermobility in sagittal or horizontal planes must be fused and instrumented.

Adult↗
PubMed2002

Intraoperative neurophysiologic detection of iatrogenic C5 nerve root injury during laminectomy for cervical compression myelopathy.

STUDY DESIGN: A retrospective and prospective study was conducted to investigate intraoperative neurophysiologic monitoring during cervical laminectomy to detect iatrogenic C5 nerve root palsy. OBJECTIVE: To evaluate the usefulness of various intraoperative neuromonitoring methods for identifying C5 nerve root palsy. SUMMARY OF BACKGROUND DATA: One unsolved complication after laminectomy or laminoplasty for cervical compression myelopathy is C5 nerve root palsy. It can go undetected even in the presence of intraoperative neuromonitoring with conventional upper extremity mixed nerve or dermatomal somatosensory-evoked potentials or transcranial motor-evoked potentials, recording typically from hand muscles. METHODS: The intraoperative neuromonitoring data of 200 patients who underwent cervical laminectomy for myelopathy between 1998 and 2000 were reviewed for C5 nerve root palsy. Retrospective studies were conducted for the first 132 patients, who were monitored with conventional techniques including ulnar and posterior tibial nerve somatosensory-evoked potentials, C5-C7 dermatomally evoked potentials, and transcranial electrical motor-evoked potentials recorded from hand and leg muscles. Prospective studies then were applied to the remaining 68 patients, for whom transcranial electrical motor-evoked potentials and spontaneous electromyography were monitored from deltoid and biceps muscles in the wake of undetected C5 nerve root palsy from conventional neurophysiologic monitoring methods. RESULTS: In the retrospective cohort, six patients presented after surgery with C5 nerve root palsy showing unilateral deltoid muscle paralysis despite entirely unremarkable conventional somatosensory-evoked potentials, dermatomally evoked potentials, and transcranial electrical motor-evoked potentials from hand and leg muscles. For the prospective cohort, two patients experienced postoperative iatrogenic C5 motor nerve root palsy. Impending C5 nerve root injuries after laminectomy were successfully identified in both patients showing significant changes in deltoid and biceps transcranial electrical motor-evoked potentials and spontaneous electromyography, thereby averting more serious consequence. There were no false-negative and false-positive results. CONCLUSIONS: In an effort to reduce postoperative C5 nerve root palsy, the clinician should consider intraoperative deltoid and biceps transcranial electrical motor-evoked potential and spontaneous electromyography monitoring whenever there is potential for iatrogenic C5 nerve root injury.

Adult↗
PubMed2004

Effect of sagittal plane deformity of the lumbar spine on epidural fibrosis formation after laminectomy: an experimental study in the rat.

STUDY DESIGN: An animal model of postlaminectomy lumbar column sagittal plane deformity was designed in rats. OBJECTIVES: To analyze the effect of lumbar column deformity (lordosis and kyphosis) on postlaminectomy epidural fibrosis formation. SUMMARY OF BACKGROUND DATA: Incidence of peridural fibrosis formation after lumbar spinal surgery is considerably high. Instability and sagittal plane deformity of the lumbar spine has been implicated (not proven) as the factors for the development of epidural fibrosis. The effect of traction (kyphosis) or relaxation (lordosis) of the lumbar spine on epidural fibrosis formation is not known. METHODS: L4 laminectomies were performed in 30 rats. Three equal groups were formed. In the control group (group I), only laminectomy was performed. In other groups after laminectomy, lumbar lordosis (group II) and kyphosis (group III) was maintained with steel implants. The scar formation was evaluated both histologically and histomorphometrically on the 12th postoperative week. RESULTS: Kyphosis developed in group I. The mean amount of peridural scar tissue was significantly more evident in groups I and III than the lordosis group. The extent of adherence to the dura mater and the nerve roots was most apparent in group III. CONCLUSIONS: Kyphosis and consequent traction of the lumbar spine is one of the causes for increased epidural fibrosis formation after laminectomy. On the contrary, establishment of lordosis and relaxation of the lumbar spine decreased the scar tissue formation in rats.

Animals↗
PubMed2006

Quantitative prediction of spinal cord drift after cervical laminectomy and arthrodesis.

STUDY DESIGN: Retrospective review of radiographic parameters. OBJECTIVES: To identify preoperative radiographic parameters that may be quantitatively predictive of postoperative spinal cord drift after cervical laminectomy and arthrodesis. SUMMARY OF BACKGROUND DATA: Cervical laminectomy and arthrodesis can be an effective method to treat anterior compressions of the spinal cord if there is a sufficient posterior spinal cord drift after surgery. Preoperative cervical alignment has shown some correlations to the degree of spinal cord shift, but whether this and other preoperative radiographic parameters can be used to quantitatively predict the amount of spinal cord drift is unclear. MATERIALS AND METHODS: Preoperative and postoperative radiographs (radiographs, MRIs, and CT) of patients who had cervical laminectomy and arthrodesis were reviewed retrospectively. Various radiographic parameters, including sagittal alignment, longitudinal distance index, space available for the spinal cord at cephalad or caudad levels, and distance from apex of the lordosis to the C2-C7 vertical line were measured. In the first cohort of patients, these parameters were correlated with mean postoperative spinal cord shift to identify any relationships. In the second cohort of patients, the identified association was used on preoperative imaging studies to attempt quantitative prediction of the postoperative spinal cord shift. RESULTS: Space available for the spinal cord at the level immediately cephalad to the laminectomized segments had high correlations (R = 0.94) to the postoperative spinal cord shift. This association was used to quantitatively predict postoperative spinal cord shift within 11% +/- 6% of the measured value. If 4 mm of mean postoperative spinal cord shift is desired, the ratio to the available space and anterior posterior diameter of the spinal cord should be approximately 2.0. CONCLUSION: Relative stenosis at the level directly cephalad to the laminectomized level can affect the degree of postoperative spinal cord shift. Preoperative axial imaging studies should be closely scrutinized to ensure that adequate space is available at the cephalad adjacent level to allow sufficient cord shift after decompressive laminectomy and arthrodesis.

Cervical Vertebrae↗
PubMed2005

Biomechanical analysis of the disc adjacent to posterolateral fusion with laminectomy in lumbar spine.

OBJECTIVES: After posterolateral fusion with laminectomy for the degenerative lumbar spine, accelerated degeneration of the disc adjacent to the fusion mass has been clinically observed. Previous studies used a finite element model (FEM) to calculate the stress of the adjacent disc in the fused lumbar spine with spinal fixator and bone graft. However, little emphasis was placed on the simultaneous spinal fusion and decompression procedure. To investigate if the spinal decompression procedure in posterolateral fusion would increase stress significantly, the FEM was employed to estimate the stress concentration of the disc above the fusion mass in posterolateral fusion with laminectomy and hemilaminectomy. METHODS: Three FEMs of the lumbar spine were established: intact spine, posterolateral fusion with total laminectomy, and posterolateral fusion with hemilaminectomy (preserved partial lamina, spinous process, and supraspinous and interspinous ligaments). The posterolateral fusion added spinal fixator and bone graft between the transverse process. The L1 vertebral body was subjected to 10-Nm flexion, extension, torsion, and lateral bending. The bottom of the L5 vertebral body was fixed. RESULTS: In flexion, the stress on the adjacent disc in posterolateral fusion with laminectomy and hemilaminectomy respectively increased 90% and 21% over that of the intact spine. In posterolateral fusion with hemilaminectomy, the supraspinous and interspinous ligaments shared some external forces to alleviate the stress concentration of the adjacent disc. However, in extension, torsion, and lateral bending, these two fusion models had almost no change in range of motion and stress of adjacent disc. CONCLUSION: Posterolateral fusion with hemilaminectomy (preserved partial lamina, spinous process, and supraspinous and interspinous ligaments) was able to alleviate the stress concentration of the disc above the fusion mass in flexion.

Biomechanical Phenomena↗
PubMed1999

The assessment of appropriate indications for laminectomy.

We have developed criteria to determine the appropriate indications for lumbar laminectomy, using the standard procedure developed at the RAND corporation and the University of California at Los Angeles (RAND-UCLA). A panel of five surgeons and four physicians individually assessed 1000 hypothetical cases of sciatica, back pain only, symptoms of spinal stenosis, spondylolisthesis, miscellaneous indications or the need for repeat laminectomy. For the first round each member of the panel used a scale ranging from 1 (extremely inappropriate) to 9 (extremely appropriate). After discussion and condensation of the results into three categories laminectomy was considered appropriate in 11% of the 1000 theoretical scenarios, equivocal in 26% and inappropriate in 63%. There was some variation between the six categories of malalignment, but full agreement in 64% of the hypothetical cases. We applied these criteria retrospectively to the records of 196 patients who had had surgical treatment for herniated discs in one Swiss University hospital. We found that 48% of the operations were for appropriate indications, 29% for equivocal reasons and that 23% were inappropriate. The RAND-UCLA method is a feasible, useful and coherent approach to the study of the indications for laminectomy and related procedures, providing a number of important insights. Our conclusions now require validation by carefully designed prospective clinical trials, such as those which are used for new medical techniques.

Back Pain↗
PubMed1999

Anterior cervical corpectomy in patients previously managed with a laminectomy: short-term complications.

BACKGROUND: The purpose of this study was to evaluate the complications of anterior cervical corpectomy and arthrodesis in patients who had had a previous cervical laminectomy. The results of previous studies have suggested that these patients can be managed with anterior decompression and an arthrodesis with either plate fixation or immobilization in a halo vest. However, no studies that we are aware of have specifically focused on the complications of these types of procedures. METHODS: The records and radiographs of eighteen patients who had been managed with a one to four-level corpectomy with strut-grafting were retrospectively reviewed. The reviews were independently performed by the three of us who were not involved in the original operation. The interval between the laminectomy and the corpectomy ranged from one month to twenty-two years (mean, eight years). RESULTS: Eleven of the eighteen patients sustained a total of sixteen complications during the follow-up period, which averaged 2.7 years (range, seven months to six years and four months), and nine of the eleven had graft-related complications. Five grafts extruded or collapsed, or both. There were four reoperations. Immobilization in a halo vest did not prevent extrusions, as three of the four extrusions occurred while the patient wore a halo vest. Four patients had a pseudarthrosis. In three patients, the kyphosis increased by 10 degrees or more from the immediate preoperative period to the most recent follow-up evaluation. Two patients had respiratory distress that necessitated reintubation, one patient had a small dural tear, and one had transient dysphagia. CONCLUSIONS: Our data suggest that anterior cervical corpectomy without instrumentation in a patient who has had a previous laminectomy is associated with a great risk of graft-related complications despite the use of a halo vest. This previously unreported finding is relevant in that it contradicts the recommendation previously made by Zdeblick and the senior one of us, who advocated postoperative immobilization in a halo vest for these patients. Anterior cervical corpectomy should be performed with caution and knowledge of the potential complications in a patient who has had a previous laminectomy.

Adult↗
PubMed2001

Microsurgical decompression without laminectomy in lumbar spinal stenosis.

Our objectives were to study a/ the clinical results of microsurgical decompression without laminectomy compared to those reported from standard decompression laminectomy in patients with central lumbar spinal stenosis, and b/ if the microsurgical technique could prevent post-operative instability and concomitant symptoms. Twenty-one patients were treated, 11 men and 10 women, aged 47-81 years. Fourteen patients had "pure" stenosis whereas 7 had additional diseases that compounded the symptoms of stenosis. Independent examiners saw the patients pre-operatively and a mean of 27 months post-operatively. Plain X-ray films were taken of 14 patients a mean of 5 years post-operatively to study possible slippage. Among the 14 patients with "pure" stenosis the results were excellent in 13 and fair in 1. Among the 7 with additional diseases the outcome was excellent in 1, fair in 1, unchanged in 3 and worse in 2. The technique did not prevent post-operative slippage, which occurred in 3 of 14 patients. However, the clinical outcome was not related to slippage. We found the microsurgical technique safe and gentle with excellent possibilities for decompression of the complete spinal canal without laminectomy. The results following this procedure were well comparable to or even better than those reported following standard decompression laminectomy.

Aged↗
PubMed1984

Effect of laminectomy and anesthesia upon spinal cord blood flow.

Spinal cord blood flow (SCBF) in 10 sheep subjected to laminectomy at L6-7, T6-7, and C7-T1 was compared to that of 10 control sheep subjected to anesthesia alone. Blood flow was measured using the radioactive microsphere technique, with the PaCO2 maintained at 40 +/- 2 mm Hg. Both laminectomy and control animals showed a decrease in SCBF at a rate of 7% to 16%/hr for the 3 hours following the first blood flow determination. When prelaminectomy and postlaminectomy SCBF values were compared to their counterparts in the control animals, there were no significant differences. Laminectomy does not appear to alter SCBF from control values. Spinal evoked potentials (SEP's) were elicited in the laminectomy group by direct cord stimulation at C-7 and L-7. No changes were noted in amplitude or latency of SEP's over time in either caudal or rostral conduction.

Anesthesia, Intravenous↗
PubMed1998

Long-term follow-up results of laminectomy for cervical myelopathy caused by ossification of the posterior longitudinal ligament.

OBJECT: This retrospective study was performed to assess the long-term results of cervical laminectomy in treating ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. METHODS: The authors reviewed medical records in 44 of 52 patients who underwent cervical laminectomy between 1970 and 1985 (mean follow up 14.1 years). The neurological recovery rate after laminectomy was 44.2% after 1 year and 42.9% after 5 years. The surgical outcome was maintained after 5 years but worsened between 5 and 10 years postsurgery: the recovery rate at the last follow-up review was 32.8%. Using multivariate stepwise analysis, the preoperative factors that affected clinical results were found to be the age at operation, the severity of preexisting myelopathy, and a history of trauma. Late neurological deterioration was observed in 10 (23%) of 44 patients. The earliest deterioration occurred at 1 year and the latest was at 17 years postsurgery (mean 9.5 years). The most frequent cause of deterioration was trauma due to a fall (six patients), followed by ossification of the ligamentum flavum (three patients). Postoperative spread of the OPLL was noted in 70% of the patients, but it was clearly the cause of neurological deterioration in only one of them. After laminectomy, postoperative progression of kyphotic deformity was observed in 47% of patients, but these changes did not cause neurological deterioration. CONCLUSION: The authors recommend early surgical decompression for OPLL because the outcome is better for younger patients and for those with a higher score as measured by the Japanese Orthopedic Association's system.

Accidental Falls↗
PubMed2001

Use of a collagen-based sealant to prevent in vivo epidural adhesions in an adult rat laminectomy model.

OBJECT: The authors investigated the effect of a collagen-based sealant, Gel Amidon Oxydé (GAO), in the prevention of epidural scar adhesions in an adult rat model of laminectomy. METHODS: Seventy-two adult Sprague-Dawley rats underwent an L5-6 laminectomy, after which the dura mater and the left L-4 and L-5 nerve roots were exposed. In the 36 animals that received GAO, the sealant was applied over the dura and around the nerve roots, and it was used to fill the laminectomy cavity before it polymerized. In 36 control animals, the same surgical treatment was performed, but the rats did not receive GAO. During the early postoperative period, a significant decrease in the occurrence of epidural hematoma was found in the GAO-treated rats. In contrast to findings in control rats, a thin white connective tissue layer was found between the dura and surrounding muscles after GAO had degraded and been absorbed. One month posttreatment, no epidural scar adhesion was found between the tissue layer and the dura in the GAO-treated animals. Three months postoperatively, both gross inspection and histological examination further confirmed that formation of epidural adhesions was significantly inhibited in the rats treated with GAO. No special inflammatory reaction was observed, and the healing of skin and muscle lesions was not affected by either treatment. CONCLUSIONS: The data obtained in this study suggest that the GAO collagen-based sealant may be an effective biomaterial to prevent epidural adhesions in vivo after laminectomy.

Animals↗
PubMed2002

A collagen-based sealant to prevent in vivo reformation of epidural scar adhesions in an adult rat laminectomy model.

OBJECT: The authors investigated the effect of a collagen-based sealant, Gel Amidon Oxydé (GAO), in preventing the reformation of epidural scar adhesions in an adult rat model of laminectomy. METHODS: Thirty-two adult Sprague-Dawley rats underwent a complete L5-6 laminectomy, after which the dura mater was exposed and the left adjacent L-4 and L-5 nerve roots were exposed. The surgical wound was then closed; 1 month later it was reopened. The epidural scar adhesions that developed were observed and carefully removed, leaving clean dura and nerve roots reexposed. In 16 experimental rats, GAO was placed onto the reexposed dura and around the nerve roots before it polymerized. No treatment was performed in 16 control rats. Postoperatively, all rats were healthy and without neurological deficit. The incisions healed within 1 week regardless of the treatment with the GAO. Three months after reoperation, magnetic resonance imaging revealed that important epidural adhesions were present in the control rats but not in the experimental rats. These findings were then confirmed by gross anatomical examination in which a white tissue layer was found over the dura without adhesions in the experimental animals, whereas significant epidural scar adhesions were demonstrated in the controls. Histological evaluation of the laminectomy site also showed that the peridural space in the experimental rats was larger than that in the controls. CONCLUSIONS: The authors found that GAO may be a safe and effective antiscarring adhesion biomaterial in vivo. When placed into the laminectomy site, GAO may prove beneficial in preventing the formation and reformation of epidural scar adhesions in humans.

Animals↗
PubMed2006

The role of mitomycin C in reducing recurrence of epidural fibrosis after repeated operation in a laminectomy model in rats.

OBJECT: Extensive peridural fibrosis after lumbar spine surgery may contribute to poor outcome and recurrent symptoms leading to repeated operation. Secondary procedures are considerably hampered by the presence of scar tissue. Moreover, after excision of the peridural scar, the fibrous tissue may recur, leading to unsuccessful surgical outcome. Mitomycin C (MMC), an alkylating antibiotic substance isolated from Streptomyces caespitosus, potentially suppresses fibroblast proliferation after surgical intervention. The authors investigated the effect of MMC on the reformation of epidural fibrosis in a laminectomy model in rats. METHODS: Twenty-four Wistar rats underwent a repeated lumbar laminectomy 3 months after the first operation. In 12 rats, MMC in a concentration of 1 mg/ml was locally applied to the laminectomy site. No treatment was performed in the control group of the other 12 rats. All rats underwent clinical evaluation. Mobility ratings and any evidence of neurological deficit were recorded. Twelve weeks after the second operation, the animals were killed for histological examination. The extent of epidural fibrosis and dural adherence was evaluated. All MMC-treated animals showed reduced epidural scarring, compared with the control group. In nine MMC-treated rats (75%), dural adhesions were moderate. In contrast, all control sites showed dense epidural fibrosis with marked dural adherence. No side effects of the treatment were observed. CONCLUSIONS: In this experimental study, MMC in a concentration of 1 mg/ml locally applied significantly reduced recurrence of epidural fibrosis and dural adhesions without any side effects after repeated spinal surgery in a laminectomy model in rats.

Alkylating Agents↗