Metformin-grafted polycaprolactone nanoscaffold targeting sensory nerve controlled fibroblasts reprograming to alleviate epidural fibrosis

Epidural fibrosis (EF), associated with various biological factors, is still a major troublesome clinical problem after laminectomy. In the present study, we initially demonstrate that sensory nerves can attenuate fibrogenic progression in EF animal models via the secretion of calcitonin gene-related peptide (CGRP), suggesting a new potential therapeutic target. Further studies showed that CGRP could inhibit the reprograming activation of fibroblasts through PI3K/AKT signal pathway. We subsequently identified metformin (MET), the most widely prescribed medication for obesity-associated type 2 diabetes, as a potent stimulator of sensory neurons to release more CGRP via activating CREB signal way. We copolymerized MET with innovative polycaprolactone (PCL) nanofibers to develop a metformin-grafted PCL nanoscaffold (METG-PCLN), which could ensure stable long-term drug release and serve as favorable physical barriers. In vivo results demonstrated that local implantation of METG-PCLN could penetrate into dorsal root ganglion cells (DRGs) to promote the CGRP synthesis, thus continuously inhibit the fibroblast activation and EF progress for 8 weeks after laminectomy, significantly better than conventional drug loading method. In conclusion, this study reveals the unprecedented potential of sensory neurons to counteract EF through CGRP signaling and introduces a novel strategy employing METG-PCLN to obstruct EF by fine-tuning sensory nerve-regulated fibrogenesis.

Cinnamaldehyde has Antifibrotic Effects on Rats with Epidural Fibrosis

BACKGROUND

Laminectomy is a widely employed surgical procedure for the treatment of spinal stenosis, but it may lead to epidural fibrosis (EF) and failed back surgery syndrome. Cinnamaldehyde, a phenylpropanoid found in cinnamon, has demonstrated antioxidant and anti-inflammatory properties. In the present study, we hypothesized that topical application and systemic administration of cinnamaldehyde could be helpful in the prevention of EF in a rat laminectomy model.

METHODS

The rats were randomly assigned to control, local, and systemic Tween-80 and local and systemic cinnamaldehyde experimental groups (n = 6, per group). In the control group, just laminectomy was performed. In local treatment groups, applications were done just after the laminectomy onto dura. In systemic treatment groups, intraperitoneal administrations were performed following skin suturing. The degree of epidural fibrosis was evaluated macroscopically and histopathologically 4 weeks later.

RESULTS

Macroscopic assessment revealed decreased EF with both topical and systemic cinnamaldehyde application, whereas microscopic examination results were not significant.

CONCLUSIONS

Our findings provide the first experimental evidence of cinnamaldehyde's potential protective effects against EF.

Pharmacotherapies to prevent epidural fibrosis after laminectomy: a systematic review of in vitro and in vivo animal models

BACKGROUND CONTEXT

Excessive production of epidural fibrosis in the nerve root can be a pain source after laminectomy. Pharmacotherapy is a minimally invasive treatment option to attenuate epidural fibrosis by suppressing proliferation and activation of fibroblasts, inflammation, and angiogenesis, and inducing apoptosis.

PURPOSE

We reviewed and tabulated pharmaceuticals with their respective signaling axes implicated in reducing epidural fibrosis. Additionally, we summarized current literature for the feasibility of novel biologics and microRNA to lessen epidural fibrosis.

STUDY DESIGN/SETTING

Systematic Review.

METHODS

According to the PRISMA guidelines, we systematically reviewed the literature in October 2022. The exclusion criteria included duplicates, nonrelevant articles, and insufficient detail of drug mechanism.

RESULTS

We obtained a total of 2,499 articles from PubMed and Embase databases. After screening the articles, 74 articles were finally selected for the systematic review and classified based on the functions of drugs and microRNAs which included inhibition of fibroblast proliferation and activation, pro-apoptosis, anti-inflammation, and antiangiogenesis. In addition, we summarized various pathways to prevent epidural fibrosis.

CONCLUSION

This study allows a comprehensive review of pharmacotherapies to prevent epidural fibrosis during laminectomy.

CLINICAL SIGNIFICANCE

We expect that our review would enable researchers and clinicians to better understand the mechanism of anti-fibrosis drugs for the clinical application of epidural fibrosis therapies.

Is Tranexamic Acid an Effective Prevention in the Formation of Epidural Fibrosis? Histological Evaluation in the Rats

OBJECTIVE

The present study aimed to determine the topical and systemic efficacy of tranexamic acid (TXA) on epidural fibrosis in a rat laminectomy model.

METHODS

Thirty-two 12-month-old adult Sprague-Dawley rats were used in this study. Each rat underwent bilateral laminectomy at the L1 and L2 vertebral levels. Rats were divided into four groups : in group I (control group, n=8), a laminectomy was performed and saline solution was applied into the surgical space. In group II (topical group, n=8), laminectomy was performed and 30 mg/ kg TXA was applied to the surgical site before skin closure. In group III (systemic group, n=8), 30 mg/kg TXA was administered intravenously via the tail vein in the same session as the surgical procedure. In group IV (topical and systemic group, n=8), TXA was administered 30 mg/kg both topical and intravenous. The rats were sacrificed at 4 weeks postoperatively. Masson's trichrome and hematoxylin and eosin were used to assess acute inflammatory cells, chronic inflammatory cells, vascular proliferation, and epidural fibrosis.

RESULTS

Epidural fibrosis, acute inflammation, chronic inflammation, and sum histologic score value were significantly lower in the systemic TXA group, systemic and topical TXA groups than in the control group (p<0.05). In addion, the sum histologic score was significantly lower in the topical TXA group than in the control group (p<0.05).

CONCLUSION

In this study, epidural fibrosis formation was prevented more by systemic application, but the topical application was found to be effective when compared to the control group. As a result, we recommend the systemic and topical use of TXA to prevent epidural fibrosis during spinal surgery.

Medical ozone treatment on prevention of epidural fibrosis in the rat model

Background/Aim

Epidural fibrosis is one of the problems that can be seen after spinal surgery. The aim of this study was to investigate the possible preventive role of medical ozone (O) treatment on epidural fibrosis.

Materials and Methods

Twenty-four Sprague Dawley rats were randomly split into four groups: control (C), O, laminectomy (L), and L+O groups. Animals in the C group were sacrificed at the beginning of the experiment. The L and L+O groups had L procedure, while O treatment was supplied for the O and O+L groups. After 42 days of follow-up, for histological evaluation and biochemical measurements, the ratio of epidural fibrosis and catalase (CAT) with malondialdehyde (MDA) levels in serum, respectively, were analyzed in terms of statistical differences.

Results

Histologically, a distinct difference was o bserved in the epidural space after O treatment. A significant difference in epidural fibrosis areas is found to be between the O, L, and O+L groups (P < 0,0001). There was no statistically significant difference between CAT and MDA levels that were obtained by spectrophotometric analysis.

Conclusion

Histological results suggest that medical O treatment after L can be used as an alternative method to prevent epidural fibrosis. Further studies with wide cohorts and interval measures are required to detail the effects of doses.

Spinal epidural fibrosis following hemostatic agent employment

OBJECTIVE

Failed Back Surgery Syndrome (FBSS) refers to a subset of patients who have new or persistent pain after spinal surgery for back or leg pain. Epidural fibrosis (EF) is a common cause of FBSS. Many agents aiming to prevent EF have been tested. However, hemostatic agents are readily available at hospitals, easy to reach and frequently used. For these reasons, oxidized regenerated cellulose, polysaccharide hemostat, hemostatic thrombin-gelatin matrix and chitosan linear polymer were evaluated for their effects on epidural fibrosis on rats after laminectomy.

METHODS

40 Sprague-Dawley rats were randomly divided into 5 equal groups including the control group where only the laminectomy was performed. The other 4 groups received hemostatic agents after laminectomy. The rats were euthanized 45 days later and were assessed by a blinded observer to grade the fibrosis level.

RESULTS

The study revealed that oxidized regenerated cellulose, polysaccharide hemostat and hemostatic thrombin-gelatin matrix lowered the epidural fibrosis grade which was statistically significant (p < 0.001). Although chitosan linear polymer created fibrosis similar to the control group it was not proven to be statistically significant (p = 0.8999). However, when compared with other hemostatic agents it resulted in a higher fibrosis grade (p < 0.001).

CONCLUSION

The results obtained from this experimental study revealed that Pahacel, Sealfoam and Surgiflo, were effective in reducing epidural fibrosis after laminectomy in rats.

Effect of Ozone Therapy on Epidural Fibrosis in Rats

OBJECTIVE

This experimental study aimed to demonstrate the effect of medical ozone therapy on the development of epidural fibrosis.

METHODS

A total of 25 Sprague-Dawley male rats were randomly divided into three groups: control group (L3-L4 laminectomy only), systemic ozone therapy (SOT) group (L3-L4 laminectomy only + intraperitoneal 15 mL [30 mcg/mL] ozone), and local ozone therapy (LOT) group (L3-L4 laminectomy only + subcutaneous 15 mL (30 mcg/mL) ozone). Ozone therapy was administered four times on a 3-day interval during the wound healing process, with the first dose immediately administered after surgery. The effects of ozone therapy on vascular endothelial growth factor (VEGF), inflammation, and epidural fibrosis between groups were evaluated.

RESULTS

Staining with VEGF was significantly less in the group that received SOT compared to the control group (p=0.021). When the groups were compared in terms of inflammation, it was found that inflammation was less common in the SOT and LOT groups compared to the control group (SOT vs control: p=0.004 and LOT vs control: p=0.024), while inflammation was found to be significantly less in the SOT group compared to the LOT group (p= 0.008). In the histopathological evaluation of epidural fibrosis, there was no significant difference between the SOT and LOT groups, but less epidural fibrosis was observed in both groups compared to the control group (LOT vs control: p=0.037; SOT vs. control: p=0.018).

CONCLUSIONS

Medical ozone therapy may be an alternative method that can be used effectively and safely in the prevention of epidural fibrosis after laminectomy.

Protective and Therapeutic Effects of Bovine Amniotic Fluids Collected in Different Trimesters on the Epidural Fibrosis After Experimental Laminectomy in Rats

BACKGROUND

The aim of this study was to investigate the protective and therapeutic effects of bovine amniotic fluid (BAF) on the inhibition of epidural fibrosis (EF) after experimental laminectomy.

METHODS

Forty female Sprague Dawley rats were used. The amniotic fluids were collected from each trimester of a pregnant cow. The rats were divided into 5 groups. Whereas no laminectomy was applied to the control group, animals in the sham group underwent laminectomy. Laminectomy was performed in the animals in other groups and the operation area was closed by dripping 1 mL of BAF collected in 3 trimesters of pregnancy. Animals were killed 28 days after the operation.

RESULTS

Compared with control, VEGF gene expression levels were downregulated approximately 5-fold in BAF-2. Whereas IL-6 was upregulated approximately 8-fold in the sham, it was downregulated 5-fold and 3-fold in BAF-1 and BAF-2, respectively. There was downregulation in BAF-2 and BAF-3 in terms of CD105 gene expression levels. TGFβ1 was upregulated approximately 2-fold in the sham group and downregulated in BAF-1 and BAF-2. Although histopathologic alterations including EF grade and fibroblast cell density were found to increase in the sham group, all BAF treatment decreased those of alterations. The highest CD105 immunoreactivity was detected in the sham group. All BAF treatment markedly aggravated fibrosis via decreasing CD105 immunoreactivity. In terms of grading parameters, almost the closest grades to the control were determined in the BAF-2. BAF collected in the second trimester is most effective in healing of scar tissue and preventing fibrosis via decreasing microvessel and fibroblast densities.

CONCLUSIONS

The results indicate that BAF may be used as a potential protective agent to prevent EF.

The Comparative Effects of Dexamethasone, Nanocurcumin, and Coenzyme Q10 Against Lumbar Laminectomy-Induced Epidural Fibrosis in a Rat Model

BACKGROUND

One of the major problems in neurosurgical procedures is fibrosis formation. Therefore, the prevention of fibrosis is an important issue in spinal cord injury that needs to be addressed. No approved therapy has yet been found, and epidural fibrosis (EF) is a huge treatment challenge. In this regard, new drugs that can effectively prevent EF are still being considered. Hence, this study aimed to investigate the effects of dexamethasone (DEX), nanocurcumin (Nano-CUR), and coenzyme Q10 (CoQ10) on the prevention of EF in a rat laminectomy model.

METHODS

Thirty-five Sprague-Dawley male rats were randomly divided into 5 groups: sham group, laminectomy group, laminectomy + DEX group, in which 0.5 ml DEX (8 mg/ml) was applied locally on the laminectomy area, laminectomy + Nano-CUR group, in which 100 mg/kg Nano-CUR was administered intraperitoneally once a day for 7 days, and laminectomy + CoQ10 group, in which 30 mg/kg CoQ10 was administered once daily intraperitoneally for 7 days. After 4 weeks, the vertebral columns were removed from L1 and L3 and prepared for histopathological assays.

RESULTS

The local administration of DEX could not improve the histological parameters, and EF was induced by laminectomy after 4 weeks. On the other hand, Nano-CUR could ameliorate EF at the laminectomy site compared to the laminectomy group, but the difference was not statistically significant. CoQ10 significantly reduced EF (P < 0.05), collagen density (P < 0.01), and inflammation in the arachnoid layer (P < 0.01).

CONCLUSIONS

Our findings showed that Nano-CUR and CoQ10 had the potential to be used for treatment of EF.

IL-33 Promotes ST2-Dependent Fibroblast Maturation via P38 and TGF-β in a Mouse Model of Epidural Fibrosis

BACKGROUND

Recent evidence suggests that IL-33, a novel member of the IL-1β family, is involved in organ fibrosis. However, the roles of IL-33 and its receptor ST2 in epidural fibrosis post spine operation remain elusive.

METHODS

A mouse model of epidural fibrosis was established after laminectomy. IL-33 in the wound tissues post laminectomy was measured with Western blotting, ELISA and immunoflurosence imaging. The fibroblast cell line NIH-3T3 and primary fibroblasts were treated with IL-33 and the mechanisms of maturation of fibroblasts into myofibroblasts were analyzed. To explore roles of IL-33 and its receptor ST2 in vivo, IL-33 knockout (KO) and ST2 KO mice were employed to construct the model of laminectomy. The epidural fibrosis was evaluated using H&E and Masson staining, western-blotting, ELISA and immunohistochemistry.

RESULTS

As demonstrated in western blotting and ELISA, IL-33 was increased in epidural wound tissues post laminectomy. The immunoflurosence imaging revealed that endothelial cells (CD31⁺) and fibroblasts (α-SAM⁺) were major producers of IL-33 in the epidural wound tissues. In vitro, IL-33 promoted fibroblast maturation, which was blocked by ST2 neutralization antibody, suggesting that IL-33-promoted-fibroblasts maturation was ST2 dependent. Further, IL-33/ST2 activated MAPK p38 and TGF-β pathways. Either p38 inhibitor or TGF-β inhibitor decreased fibronectin and α-SAM production from IL-33-treated fibroblasts, suggesting that p38 and TGF-β were involved with IL-33/ST2 signal pathways in the fibroblasts maturation. In vivo, IL-33 KO or ST2 KO decreased fibronectin, α-SMA and collagen deposition in the wound tissues of mice that underwent spine surgery. In addition, TGF-β1 was decreased in IL-33 KO or ST2 KO epidural wound tissues.

CONCLUSION

In summary, IL-33/ST2 promoted fibroblast differentiation into myofibroblasts via MAPK p38 and TGF-β in a mouse model of epidural fibrosis after laminectomy.

Management of post-cervical laminectomy fusion pain syndrome with a successful trial of spinal cord stimulation

Introduction

Spinal cord stimulation has been shown to be beneficial in various postsurgical neuropathic pain syndromes, but the already small cervical epidural space due to epidural fibrosis makes cervical spinal cord stimulator placement very difficult. We present a case of successful cervical cord stimulator implantation in a patient with a history of anterior cervical discectomy and fusion, posterior cervical fusion, and significant epidural fibrosis.

Methods

A 48-year-old woman with a history of type 2 diabetes, nonalcoholic steatohepatitis, and fibromyalgia presented with trauma-induced cervicalgia and bilateral upper extremity radiculopathy.

Results

In a 4-day trial of stimulation, she reported an 80% reduction of her pain and significant improvement in her quality of life.

Discussion

Although anecdotal evidence and case series have shown spinal cord stimulation to be successful in cervical failed back surgery syndrome, we are the first to discuss the technical challenges and complications associated with epidural fibrosis.

Comparison of the effect of bipolar coagulation and fibrillar structured oxidized cellulose on formation epidural fibrosis in rats

Background/aim

Epidural fibrosis (EF) is a common cause of failed back surgery syndrome seen after spinal surgeries. The most frequent reason for the formation of EF is accumulated blood and its products in the operation zone. On the development of EF, the effect of bipolar coagulation and fibrillar oxidized cellulose, which are used frequently to control bleeding, was investigated.

Materials and methods

In the study, 45 male Sprague Dawley rats were divided into three groups (control, fibrillar, and bipolar). Lumbar laminectomy was applied to all rats under sterile conditions. In the control group, the epidural area was washed with saline solution. Bleeding was controlled with fibrillar oxidized cellulose in the fibrillar group, with bipolar coagulation in the bipolar group. The area to which laminectomy had been applied was removed as a block 6 weeks later and evaluated histopathologically and genetically in terms of EF development. Fibrosis degree was determined histopathologically by counting fibroblasts using the modified Lubina and EF He grading systems. Interleukin-6 (IL-6), transforming growth factor beta-1 (TGFβ-1), and mRNA levels were measured by the droplet digital polymerase chain reaction method.

Results

The number of epidural fibroblasts, percentage of modified Lubina, amount of IL-6, and He grading rates were significantly lower in the fibrillar group than in the bipolar and control groups (p ˂ 0.05). On the other hand, there was no significant difference among the control, fibrillar, and bipolar groups in terms of TGFβ-1 values (p= 0.525).

Conclusion

The use of fibrillar oxidized cellulose was more effective for hemostasis than bipolar coagulation in reducing the development of EF.

Polypropylene mesh inhibits post-laminectomy compressive scar formation in rabbits: Histopathological and computational morphometric evaluation

We evaluated the effect of polypropylene mesh placement on post-laminectomy compressive scar formation in rabbits. Twenty-two white male New Zealand rabbits were distributed into two groups (n = 11). In the control group, the animals underwent lumbosacral laminectomy, whereas in the mesh group, the rabbits were submitted to lumbosacral laminectomy followed by the attachment of a polypropylene mesh to the vertebrae by the application of N-butyl cyanoacrylate. After eight weeks, the rabbits were euthanized, and the laminectomy area was collected for macro- and microscopic analyses. Macroscopically, we evaluated the (1) vertebral canal height; (2) laminectomy width and (3) length; and (4) fibrosis width, (5) height, and (6) length. Microscopically, we evaluated (7) fibroblasts; (8) the thickness of the dura-mater; and (9) the distance between the dura-mater and the laminectomy area. Macroscopically, there were no differences between the groups regarding vertebral canal height; width and length of the laminectomy; and fibrosis width. However, the height, and length of fibrosis were smaller in the mesh group. Microscopically, there were no differences in dura mater thickness and the distance between the dura mater and laminectomy area, but fewer fibroblasts were observed in the mesh group. This indicated that the polypropylene mesh improved tissue repair, with greater tissue organization. The results demonstrate that the use of a polypropylene mesh in the treatment of post-laminectomy wounds in rabbits reduces the severity of compressive fibrous scar formation. Polypropylene mesh is presented as a good alternative to reduce complications associated with laminectomy surgeries.

Postoperative Epidural Fibrosis Prevention: Which Is Better-Autologous Fat versus Gelfoam

Study Design

Prospective, randomized study of 100 patients with prolapsed intervertebral disc with an average of 12- to 18-month follow-up postoperatively.

Purpose

To compare the role of Gelfoam and autologous fat in the prevention of postoperative epidural fibrosis (EF) after lumbar spine surgery.

Overview of Literature

EF is a possible sequelae of lumbar disc surgery. Different treatments and surgical strategies have been attempted to prevent postoperative fibrosis without providing consistent long-term results.

Methods

The study was conducted on 100 adult patients. The patients were randomly allocated into two groups of 50 patients each: group A, autologous fat group, and group B, Gelfoam group. The postoperative follow-up was conducted at intervals of 6 weeks, 3 months, 6 months, and 12 months. Both groups were evaluated clinically (Oswestry Low Back Pain Disability Questionnaire [ODI], Visual Analog Scale [VAS], Straight Leg Raising Test [SLRT]) and radiologically (using Ross grading by contrast magnetic resonance imaging [MRI]) for development of radicular pain and hence EF.

Results

Based on the analysis, improvement in mean values of ODI score, VAS score, and SLRT were found to be statistically significant postoperatively at intervals of 6 weeks, 3 months, 6 months, and 12 months when compared individually in both groups. However, improvement was greater in the autologous fat group than in the Gelfoam group. Based on contrast-enhanced MRI, the number of patients who developed EF was smaller in the autologous fat group than in the Gelfoam group.

Conclusions

In the present study, on clinical and radiological assessment, we conclude that both groups prevent radicular pain and postoperative EF individually but relatively autologous fat was found to be more effective than Gelfoam in the prevention of EF and hence radicular pain.

Pirfenidone inhibits fibroblast proliferation, migration or adhesion and reduces epidural fibrosis in rats via the PI3K/AKT signaling pathway

OBJECTIVE

This present study aims to assess the effect of pirfenidone (PFD) on inhibiting fibroblast proliferation, migration or adhesion in vitro and reducing laminectomy-induced epidural fibrosis in vivo.

METHODS

The effect of PFD on proliferation inhibition was evaluated with flow cytometry, CCK-8, EdU and western-blotting assays. Altered properties in migration and adhesion were confirmed by wound-scratch, transwell, immunofluorescence (IF), cell adhesion and western-blotting assays. Additionally, fifty male healthy Sprague-Dawley rats were subjected to laminectomy and then treated with various concentrations of PFD. After 4 weeks, the degree of epidural fibrosis was evaluated by histological analysis.

RESULTS

In vitro, the results of flow cytometry, CCK-8, EdU and western-blotting assays showed that PFD reduced fibroblast proliferation by a dose-dependent manner. And the results of wound-scratch, transwell, IF, cell adhesion and western-blotting assays showed that the migration and adhesion of fibroblasts could be inhibited and the cytoskeleton could also be altered in a dose-dependent manner. And the inhibitory effect of PFD could be partially reversed in the PI3K overexpression experiment, which indicated that the capability of PFD to inhibit fibroblast proliferation, migration and adhesion might be through the PI3K/AKT signaling pathway. In vivo, an obvious reduction in epidural fibrosis was observed in groups topically treated with PFD.

CONCLUSIONS

Topical PFD application obviously suppressed laminectomy-induced epidural fibrosis, possibly by inhibiting fibroblast proliferation, migration and adhesion via the PI3K/AKT signaling pathway. PFD may be a safe and effective pharmaceutical to reduce clinical epidural fibrosis.

MICAL2 regulates myofibroblasts differentiation in epidural fibrosis via SRF/MRTF-A signaling pathway

AIM

To determine the role of MICAL2 in myofibroblasts differentiation and epidural fibrosis.

BACKGROUND

Epidural fibrosis (EF) may develop following laminectomy and aberrant myofibroblasts differentiation and excessive extracellular matrix (ECM) accumulation play key roles in the formation of EF. Dense epidural fibrosis results to the poor surgical outcomes and failed back surgery syndrome (FBSS), and there is no effective treatment available. Molecule interacting with Casl2 (MICAL2) has been demonstrated to participate in multiple cellular processes by regulating actin cytoskeleton dynamics. However, its role in epidural fibrosis remains totally unverified.

MATERIALS AND METHODS

The potential functions and mechanisms of MICAL2 were explored using western blotting, immunofluorescence and lentivirus infection.

KEY FINDINGS

In our study, we determined that the MICAL2 expression was elevated in epidural fibrotic tissues and TGF-β1-stimulated fibroblasts. Moreover, knockdown of MICAL2 using MICAL2-specific short hairpin RNA attenuated TGF-β1-induced myofibroblasts differentiation and epidural fibrosis both in vitro and vivo, as indicated by decreased scar formation, reduced collagen production and down-regulated expression of α-SMA, collagen-1 and fibronectin. We also demonstrated that MICAL2 knockdown affected the migratory capability of fibroblasts in vitro. By further mechanistic research, we revealed that the MRTF-A nuclear translocation was inhibited in response to the knockdown of MICAL2 in fibroblasts and MICAL2 served as a pro-fibrotic factor in an SRF/MRTF-A-dependent manner.

SIGNIFICANCE

In conclusion, our results indicated that MICAL2 mediated myofibroblasts differentiation and promoted epidural fibrogenesis via SRF/MRTF-A signaling pathway, suggesting manipulation of MICAL2 activity as a novel alternative strategy for the prevention of epidural fibrosis.

Differentiating epidural fibrosis from disc herniation on contrast-enhanced and unenhanced MRI in the postoperative lumbar spine

OBJECTIVE

To determine diagnostic confidence and inter-observer/intra-observer agreement in differentiating epidural fibrosis from disc herniation and lumbar spinal stenosis parameters on magnetic resonance images (MRI) in postoperative lumbar spines with (Gad-MRI) and without (unenhanced MRI) intravenous gadolinium-based contrast agent.

SUBJECTS AND METHODS

N = 124 lumbar spine MRI examinations of four groups were included: 1-6 months, 7-18 months, 19-36 months, more than 37 months between lumbar spine surgery and imaging. Two radiologists evaluated Gad-MRI and unenhanced MRI: diagnostic confidence was determined as confident or unconfident. Inter-observer and intra-observer agreement were assessed in differentiating epidural fibrosis from disc herniation and for lumbar spinal stenosis parameters on MRI. Fisher's exact test and Cohen's kappa served for statistics.

RESULTS

Diagnostic confidence in differentiating epidural fibrosis from disc herniation was significantly higher on Gad-MR images compared with unenhanced MRI at 1-18 months for observer 1 and at 1-6 months postoperatively for observer 2 (p values: 0.01-0.025). Inter-observer agreement at 1-6 months postoperatively for identification of epidural fibrosis was higher on Gad-MRI (kappa values: 0.53 versus 0.24). Inter-observer and intra-observer agreement for identification of disc herniation and for assessment of lumbar spinal stenosis parameters revealed inconsistent data, without a trend for higher inter-observer or intra-observer agreement on Gad-MRI compared with unenhanced MRI (kappa values: 0.17-0.75).

CONCLUSION

Gad-MR images compared with unenhanced MRI improved diagnostic confidence and agreement in differentiating epidural fibrosis from disc herniation for both observers in the first 6 months and for one observer in the first 18 months after lumbar spine surgery. After 18 months, Gad-MR images compared with unenhanced MRI did neither improve confidence nor agreement.

A novel controlled release tetrandrine-loaded PDLLA film: evaluation of drug release and anti-adhesion effects in vitro and in vivo

To investigate the drug release and anti-adhesion effects of a TET (tetrandrine)-loaded PDLLA (poly-dl-lactide) film. Detection of TET release in vitro was carried out by high-performance liquid chromatography (HPLC) every 2 days following immersion of the tetrandrine-loaded PDLLA film in simulated body fluid until the TET content of the eluate could not be detected. For the in vivo test, TET-loaded PDLLA films were implanted into animal laminectomy models and positive and blank control groups were also set up. Postoperative serum tests, and macroscopic and histological analyses at 1, 4, 8, and 12 weeks, were used to assess the effects of the film. Statistical analyses were performed by one-way ANOVA. The drug release of the tetrandrine-loaded PDLLA film in vitro showed two phases with a second release peak. Ultimately, the duration of continuous delivery was up to 66 days and the cumulative delivery rate was up to 93.18%. Scores for the proliferation of epidural scars or adhesion of the dura mater in the test group were much lower than those for the two control groups. Histological analysis revealed the test group had fewer inflammatory cells and fibroblasts, as well as fewer extracellular collagen fibers, and a lower histology score than those of the two control groups at all time points. Tetrandrine-loaded PDLLA film is a novel controlled drug release and anti-adhesion material in vitro and in vivo.

The Preventive Effect of Curcumin on the Experimental Rat Epidural Fibrosis Model

OBJECTIVE

The aim of the study was to evaluate the effect of systemically administrated curcumin on the prevention of peridural fibrotic tissue and adhesion formation in a rat laminectomy model.

METHODS

Thirty-two Wistar albino rats were randomly selected and equally divided into 4 groups as follows: negative control group (group I) did not undergo operation; positive control group (group II) underwent laminectomy without treatment; group III (low-dose curcumin; 100 mg/kg); and group IV (high-dose curcumin; 200 mg/kg). Curcumin was administered intraperitoneally per day for 7 days after surgery starting from day 0. Twenty-eight days after surgery, T12 and L4 vertebral columns, paraspinal tissues, and epidural scar tissue were dissected en bloc and prepared for histopathologic examinations. All specimens were examined for inflammation, epidural fibrosis (EF), foreign body reaction, medulla spinalis retraction, granulation tissue, and arachnoid involvement. A Kruskal-Wallis test followed by a Dunn multiple comparison test were used for statistical analysis, and a P value <0.05 was considered as statistically significant.

RESULTS

Curcumin treatment significantly reduced inflammation, foreign body reaction, granulation tissue formation, medulla spinalis retraction, and EF formation compared with positive control group (P < 0.05); however, no significant differences were found between the 2 groups that received different doses of curcumin.

CONCLUSIONS

The results of the present study showed that systemic administration of curcumin was effective in reducing EF formation, inflammation, granulation tissue formation, medulla spinalis retraction, and foreign body reaction in the laminectomy area. Our results suggest that antiinflammatory activities of curcumin are beneficial for attenuation of EF formation.

Transiting Nerve Rootlet Abnormalities on MRI after Lumbar Laminectomy: Associations with Persistent Postoperative Pain

Objective

To determine whether changes in the transiting nerve rootlet or its surroundings, as seen on MRI performed after lumbar hemilaminectomy, are associated with persistent postoperative pain (PPP), commonly known as the failed back surgery syndrome.

Materials and Methods

Seventy-three patients (mean age, 61 years; 43 males and 30 females) who underwent single-level partial hemilaminectomy of the lumbar spine without postoperative complications or other level spinal abnormalities between January 2010 and December 2018 were enrolled. Two musculoskeletal radiologists evaluated transiting nerve rootlet abnormalities (thickening, signal alteration, distinction, and displacement), epidural fibrosis, and intrathecal arachnoiditis on MRI obtained one year after the operations. A spine surgeon blinded to the radiologic findings evaluated each patient for PPP. Univariable and multivariable analyses were used to evaluate the association between the MRI findings and PPP.

Results

The presence of transiting nerve rootlet thickening, signal alteration, and ill-distinction was significantly different between the patients with PPP and those without, for both readers (p ≤ 0.020). Conversely, the presence of transiting nerve rootlet displacement, epidural fibrosis, and intrathecal arachnoiditis was not significantly different between the two groups (p ≥ 0.128). Among the above radiologic findings, transiting nerve rootlet thickening and signal alteration were the most significant findings in the multivariable analyses (p ≤ 0.009).

Conclusion

On MRI, PPP was associated with transiting nerve rootlet abnormalities, including thickening, signal alterations, and ill-distinction, but was not associated with epidural fibrosis or intrathecal arachnoiditis. The most relevant findings were the nerve rootlet thickening and signal alteration.

Dose preservation of ligament flavum really help prevent postoperative epidural fibrosis and improve outcome in microdiscectomy?

OBJECTIVE

A prospective, randomized, controlled clinical study was conducted with surgery performed by the same surgeon. The aim was to present a new technique for preserving the ligament flavum during lumbar microdiscectomy, and to evaluate whether this helps prevent postoperative fibrosis and improve outcome.

METHODS

From January to December 2017, 251 patients with indication for microdiscectomy were randomly divided into test group using ligament flavum preservation technique and control group using conventional procedures. Visual analogue scale (VAS) scores and Oswestry Disability Index (ODI) were assessed before the surgery, and 3 days, 1 month, 6 months, 1 year and 2 years after the operation respectively. The grade of epidural fibrosis on MRI after 6 months was evaluated by two radiologists independently and double-blindly.

RESULTS

Both groups' VAS and ODI were significantly improved after surgery, but there was no significant difference between two groups at 3d and 1 month after operation. The grade of epidural fibrosis in test group was significantly lower than that in control group at 6 months postoperative. The VAS and ODI were significantly lower in test group than that in control group at 6 months,1 year and 2 years after operation.

CONCLUSION

Preservation of more ligament flavum is practicable during the procedure of microdiscectomy. It can prevent postoperative epidural fibrosis, and is helpful to achieve a better clinical outcome.

Allicin Inhibits Proliferation and Promotes Apoptosis of Human Epidural Scar Fibroblasts

BACKGROUND

Allicin can suppress liver and cardiac fibrosis; thus, we hypothesized that it might prevent scar tissue from extensive epidural fibrosis after laminectomy.

METHODS

Human epidural scar fibroblasts were isolated from surgical specimens and treated with allicin at a gradient of concentrations. Morphology, viability, migration rate, cell cycle, and apoptosis rate were measured by fluorescence microscope, Cell Counting Kit-8 assay, scratch assay, and flow cytometry. Western blot was used to measure the expression level of proliferation-related proteins.

RESULTS

After treatment by allicin, cell viability (P = 0.042) and migration rate (P = 0.010 in scratch assay and P = 0.025 in transwell assay) decreased significantly in a dose-dependent manner. The percentage of G₁ phase cells significantly decreased (P = 0.017), whereas the percentage of S phase cells (P = 0.096) and G₂ phase cells (P = 0.038) significantly increased in a dose-dependent manner. Similarly, the percentage of apoptotic cells increased significantly in a dose-dependent manner (P = 0.036). Compared with the control group, the expression level of proliferating cell nuclear antigen protein (P = 0.081) and Bcl-2 protein (P = 0.029) significantly decreased, whereas the BAX protein level significantly increased (P = 0.017).

CONCLUSIONS

Allicin can suppress human epidural scar fibroblast migration, induce cell apoptosis, and block cell proliferation at S phase and G₂ phase.

Emodin promotes fibroblast apoptosis and prevents epidural fibrosis through PERK pathway in rats

Background

Laminectomy is usually classed as a common orthopedic surgery, but postoperative epidural fibrosis often leads to less-than-desirable clinical outcomes. As demonstrated by prior studies, emodin (EMO) exerts an anti-fibrotic effect. Here, we carried out investigation into the inhibitory effect created by EMO application on epidural fibrosis after laminectomy in rats.

Methods

The paper conducts a series of experiment. In vitro, we observed the effect of EMO on fibroblasts by Cell Counting Kit-8 (CCK-8) assay. Apoptosis of fibroblasts induced by EMO was detected by western blot, TUNEL assay, and flow cytometry. The results revealed that EMO was capable of inducing fibroblast apoptosis, and the proteins of PERK pathway also changed accordingly. In vivo, the effect of EMO on epidural fibrosis in 12 male Sprague-Dawley rats was observed by histological staining.

Results

CCK-8 assay indicated that EMO was effective in reducing fibroblast viability in a time- and a dose-dependent manner. TUNEL assay and flow cytometry analysis have demonstrated that the apoptotic rate of fibroblasts increased as the EMO concentration rose. Western blot analysis proved that EMO promoted the relative expression of p-perk and p-eIF2α and that the expression of its downstream proteins CHOP and GRP78 was also enhanced. The expression of apoptotic protein Bax and cleaved PARP was upregulated, whereas the expression of anti-apoptotic protein Bcl-2 was downregulated. In addition, histological and immunohistochemical analysis demonstrated that EMO functioned to inhibit epidural fibrosis and increase GRP78 expression in fibrous tissue by promoting apoptosis of fibroblasts.

Conclusions

EMO could have inhibitory effect on epidural fibrosis in a concentration-dependent manner. The potential mechanism might be through PERK signaling pathway to promote fibroblast apoptosis. It has a possibility to be taken as a novel method for the treatment of epidural fibrosis.

Effect of topical rifamycin application on epidural fibrosis in rats

Objectives

This study aims to investigate the effects of topical rifamycin SV application on epidural fibrosis formation in a rat model.

Materials and methods

Between March 2015 and April 2015, a total of 20 Wistar rats were equally and randomly divided into laminectomy only group (control group) and laminectomy and rifamycin SV group (treatment group). Laminectomy was performed between L3-L5 in all rats. Surgical field was irrigated with 1 mL rifamycin SV (1 mL). After four weeks, vertebral columns of the rats were removed en bloc between the L1 and L5 levels, and epidural fibrosis and arachnoid involvement were histopathologically evaluated and graded.

Results

Grade 3 epidural fibrosis formation ratio was lower in the treatment group (40%) compared to the control group (80%). However, there was no statistically significant difference between the treatment and control groups in terms of epidural fibrosis (p=0.164) and arachnoid involvement (p=0.303).

Conclusion

Intraoperative rifamycin irrigation tends to reduce epidural fibrosis formation risk, although not statistically significant.

Apigenin inhibits fibroblast proliferation and reduces epidural fibrosis by regulating Wnt3a/β-catenin signaling pathway

BACKGROUND

Failed back surgery syndrome (FBSS) is a common complication after the laminectomy. Epidural fibrosis is the major cause of lower back pain and other complications. Numerous studies have shown that apigenin (API) could treat various fibrotic diseases by regulating various signaling pathways, whereas no study has discussed whether API can inhibit fibroblast proliferation and reduce epidural fibrosis after the laminectomy by regulating Wnt3a/β-catenin signaling pathway.

METHODS

Human fibroblasts were cultured and treated with API in different concentrations for 24 h. CCK-8 detection and EdU incorporation assay were performed to detect cell viability and cell proliferation. Western blotting analysis was applied to detect expressions of proliferative proteins, Wnt3a, and its downstream proteins. Moreover, the Wnt3a gene was overexpressed in fibroblasts to define the relationship between Wnt3a/β-catenin signaling pathway and fibroblast proliferation. Wnt3a overexpressed fibroblasts were treated with API to verify if it could reverse the effects of API treatment. Twenty-four Sprague-Dawley rats were randomly divided into four groups. Laminectomy was performed and the rats were gavaged with different doses of API or 5% sodium carboxyl methyl cellulose (CMC-Na) solution for 1 month. The abilities of API to inhibit fibroblast proliferation and to reduce epidural fibrosis were evaluated using histological and immunohistochemical analysis.

RESULTS

CCK-8 detection and EdU incorporation assay demonstrated that API could inhibit the viability and proliferation rate of fibroblasts in a concentration-dependent manner. The Western blotting analysis revealed that API could inhibit the expressions of PCNA, cyclinD1, Wnt3a, and its downstream proteins. The overexpression of Wnt3a in fibroblasts could upregulate the expressions of proliferative proteins such as PCNA and cyclinD1. The inhibitory effect of API on PCNA, Wnt3a, and its downstream proteins was partially reversed by overexpression of Wnt3a. Moreover, the results of the histological and immunohistochemical analysis revealed that API could reduce the epidural fibrosis in rats by inhibiting fibroblast proliferation in a dose-dependent manner.

CONCLUSIONS

API can inhibit fibroblast proliferation and reduce epidural fibrosis by suppressing Wnt3a/β-catenin signaling pathway, which can be adopted as a new option to prevent epidural fibrosis after the laminectomy.

Pirfenidone inhibits epidural scar fibroblast proliferation and differentiation by regulating TGF-β1-induced Smad-dependent and -independent pathways

Epidural fibrosis causes serious complications in patients who have undergone laminectomy. Pirfenidone is an effective antifibrotic agent but its effect on epidural fibrosis remains unclear. In this study, we aimed to investigate the effect of pirfenidone on epidural fibrosis and to evaluate its mechanism of action on human epidural scar fibroblasts. In a rat model of laminectomy, the degree of epidural fibrosis was quantified via Rydell standard classification, histological analysis, and collagen density analyses. In cultured human epidural scar fibroblasts, cell proliferation was measured using a Cell Counting Kit-8 and EdU assay. Cell apoptosis was detected using Annexin V/propidium iodide staining, and cytotoxicity was evaluated via lactate dehydrogenase assay. Relative mRNA levels of α-smooth muscle actin (α-SMA) and collagen type I were analyzed using quantitative polymerase chain reaction. The protein expression of α-SMA and collagen type I and the phosphorylation status of Smad2, Smad3, protein kinase B (Akt), and p38 were determined via western blotting. Pirfenidone reduced epidural fibrosis by inhibiting fibroblast proliferation and suppressing collagen formation in rats. It also inhibited human epidural scar fibroblast proliferation with no cytotoxic or apoptotic effects. Pirfenidone inhibited fibroblast differentiation by decreasing TGF-β1-induced transcriptional and translational expression of α-SMA. It inhibited TGF-β1-induced phosphorylation of Smad2, Smad3, Akt, and p38. This study suggests that topical application of pirfenidone could reduce epidural scar adhesion after laminectomy, and that its mechanism of action may be the inhibition of TGF-β1-induced epidural scar fibroblast proliferation and differentiation into myofibroblasts through the attenuation of TGF-β1-induced Smad-dependent and -independent pathways.

Immunohistochemical Grading of Epidural Fibrosis with CD105 Antibody

OBJECTIVE

Grading of epidural fibrosis (EF) is usually performed by histopathologic staining in experimental studies. Immunohistochemical methods for grading are not available in routine practice yet. In our study, the effect of tranexamic acid (TXA), a commonly used hemostatic agent in surgical interventions, was evaluated for use against the development of EF with classical histopathologic methods and immunohistochemistry using the CD105 antibody, a marker of angiogenesis.

METHODS

Sixteen rats were used. The rats were assigned to 2 groups, control and TXA. Laminectomy was performed on the control group. In the treatment group, laminectomy + topical TXA was applied. After sacrificing the rats in the sixth week, histopathologic and immunohistochemical examinations and grading of the EF tissue were performed.

RESULTS

Conventional histopathologic parameters of fibroblast count, intensity of fibrosis density, and inflammatory cell density, as well as immunohistochemical evaluation with CD105, showed that the grading of EF was comparable between groups I and II (P < 0.001).

DISCUSSION

The results of our study have demonstrated that CD105 is compatible with the conventional histopathologic grading methods and can be used as a marker to determine the grades of angiogenesis and fibrosis in experimental studies. The results of our study have also shown that TXA, administered locally for hemostasis, reduces the grade of EF in rats following laminectomy. TXA has been observed to cause no toxic effects on neural tissue as it is already commonly used in clinical practice.

Antifibrotic Effect of Boric Acid in Rats with Epidural Fibrosis

BACKGROUND

Epidural fibrosis is a major problem after spine surgery, with some patients having recurrent symptoms secondary to excessive formation of scar tissue resulting in neurologic compression. We used a rat laminectomy model to determine if topical application of boric acid could be helpful in the prevention of epidural fibrosis.

METHODS

Rats were randomly assigned to 2 control and 2 experimental groups (n = 8 for each group). The negative control group received no surgery, and the positive control group underwent laminectomy only. Experimental groups were classified according to the study agents applied onto the dura mater after laminectomy at the L3 level: 2.5% boric acid solution and 5% boric acid solution. The extent of epidural fibrosis was assessed 4 weeks later macroscopically and histopathologically.

RESULTS

Boric acid reduced epidural fibrosis in rats after laminectomy. The effect of 5% boric acid solution was more pronounced (P < 0.05) compared with the 2.5% solution.

CONCLUSIONS

The antifibrotic effect of boric acid solution for the prevention of epidural fibrosis suggests that boric acid should be further evaluated in future studies for the prevention of epidural fibrosis.

Artesunate inhibits fibroblasts proliferation and reduces surgery-induced epidural fibrosis via the autophagy-mediated p53/p21waf1/cip1 pathway

Fibroblast proliferation is considered to be a major cause in the process of epidural fibrosis formation. Autophagy is a tightly-regulated catabolic process in charge of degrading intracellular components. Although autophagy has been associated with fibrosis of different tissues, the effect of autophagy on epidural fibrosis is still unknown. The aim of this study was to investigate the function and mechanism of autophagy induced by Artesunate (ART), a classical antimalarial agent extracted from the Chinese medicinal herb. In vitro, the effect of ART on inducing fibroblast autophagy was evaluated via LC3 immunofluorescent staining, Transmission Electron Microscopy (TEM) and western blotting analysis. Moreover, the effect of ART on inhibiting fibroblast proliferation was investigated by CCK-8 assay, EdU incorporation assay, flow cytometry and western blotting analysis. Results indicated that ART could induce autophagy and inhibit proliferation in fibroblasts. The inhibitory effect of ART on fibroblast proliferation was associated with the upregulation of p53 and p21^waf1/cip1 proteins. Intriguingly, 3-MA, a classical autophagy inhibitor, attenuated ART-induced p53/p21^waf1/cip1 pathway activation and fibroblast proliferation inhibition. In vivo, the effect of ART on reducing epidural fibrosis was detected by histological macroscopic assessment, hydroxyproline content analysis, histological and immunohistochemical staining. The results revealed that ART had significant suppressive effects on epidural fibrosis following laminectomy in rats. In conclusion, this research demonstrated that ART could inhibit fibroblast proliferation and reduce epidural fibrosis formation after laminectomy, and the potential mechanism might through autophagy cascade-mediated p53/p21^waf1/cip1 pathway. It might provide a novel reagent for reducing epidural fibrosis after spinal laminectomy surgery.

Effect of platelet-rich fibrin on epidural fibrosis and comparison to ADCON® Gel and hyaluronic acid

Objective

In this experimental study, PRF (Platelet Rich Fibrin), HA (Hyaluronic Acid) gel and ADCON® Gel were compared in terms of preventing epidural fibrosis.

Methods

Twenty-eight Sprague–Dawley rats (mean weight, 400–450 g) were divided into 4 groups. L3-L4 laminectomy was performed in each group. Following laminectomy, Adcon® Gel, HA gel and PRF were applied onto the surgery site locally in Group 1, 2 and 3, respectively. Group 4 was maintained as control without any local application. After five weeks, L3-L4 vertebrae were removed totally and taken to histopathological evaluation for epidural fibrosis, acute inflammatory cell density, chronic inflammatory cell density, hemorrhage, angiogenesis and new bone formation.

Results

Acute inflammation cell density, angiogenesis, and new bone formation levels were comparable among the study groups (p > 0.05). However, new bone formation was higher in the PRF group. Epidural fibrosis and chronic inflammatory cell density were significantly lower in the PRF group (p < 0.05).

Conclusion

We concluded that PRF contributed to hemostasis and prevented epidural fibrosis.

Effect of Local N-acetyl-cysteine in the Prevention of Epidural Fibrosis in Rat Laminectomy Model

Background:

Epidural fibrosis is a major contributing factor to the onset of failed back syndrome. Many studies have attempted to prevent this physiological response. Interestingly, N-acetyl-cysteine (NAC) has been effective in some cases in the treatment of pulmonary fibrosis.

Objective:

The objective of this study was to determine whether local NAC is an effective way to prevent epidural fibrosis after laminectomy in rats.

Materials and Methods:

Twenty Wistar rats were used in this study. Animals were divided into two groups: NAC group and a control group. We performed two-level laminectomy (L4–L5) in these rats. Rats in the control group just had laminectomy, and in the other group, L4 and L5 laminectomy followed by local treatment with NAC. Four weeks later, the rats were killed, and the laminectomy level was subjected to histopathological examination to evaluate epidural fibrosis and fibroblast density.

Results:

Histopathological examination showed that after 4 weeks of surgery the NAC group had significantly less epidural fibrosis and fibroblasts compared with control group.

Conclusion:

Our findings indicate that NAC decreased spinal epidural fibrosis after laminectomy in rats.

[Analysis of clinical effects in the treatment of single-segment lumbar degenerative disease by lamina osteotomy and former vertebral plates regraft]

OBJECTIVE

To compare the clinical effect between the lamina osteotomy and former vertebral plates regraft method and total laminectomy and interbody fusion method in treating single-segment lumbar degenerative disease.

METHODS

The clinical data of 167 patients with single-segment lumbar degenerative disease underwent surgical treatment from January 2010 to December 2014 were retrospectively analyzed. There were 92 males and 75 females, aged from 45 to 75 years old with an average of (59.6±12.4) years. The patients were divided into lamina osteotomy and former vertebral plates regraft group(82 cases) and total laminectomy and interbody fusion group(85 cases) according to the different surgical methods used. The general conditions and clinical effects were compared between two groups. General conditions included the operation time, intraoperative blood loss, postoperative drainage, hospitalization time and the clinical effects included the visual analogue scale (VAS), Japanese Orthopaedic Association(JOA), Oswestry Dability Index(ODI), MacNab results, epidural fibrosis (EF), the incidence of adjacent segment degeneration (ASD).

RESULTS

All the patients were followed for 18 to 36 months with an average of (24.8±5.7) months, furthermore, there was no significant difference in the follow-up time between two groups. There was no significant difference in general conditions such as operation time, intraoperative blood loss, postoperative drainage, or hospitalization time between two groups. At final follow-up, the VAS, ODI, JOA, of all patients were significantly improved (P<0.05);and the three factors above in the lamina osteotomy and former vertebral plates regraft group respectively were(2.0±1.1) points, (24.0±1.8) %, (19.8±8.2) point, while the results of total laminectomy and interbody fusion group were(2.5±1.6) points, (23.3±2.0)%, and(22.5±8.5) point;there was statistical difference between two groups(P<0.05). According to the standard of MacNab, 59 cases obtained excellent results, 20 good, 3 fair results in the lamina osteotomy and former vertebral plates regraft group;while 47 cases got excellent results, 26 good, and 12 fair results in the total laminectomy and interbody fusion group;there was significant difference between two groups(P<0.05). Sixteen patients(19.51%) with EF and 20 patients(24.39%) with ASD were found in lamina osteotomy and former vertebral plates regraft group;and 30 patients(35.29%) with EF and 37 patients(43.53%) with ASD were found in total laminectomy and interbody fusion group; there was significant difference between two groups(P<0.05).

CONCLUSIONS

Both two methods can achieve the ideal effects for the treatment of single-segment lumbar degenerative disease, but the lamina osteotomy and former vertebral plates regraft method can reserve the integrity of posterior ligamentous complex, reducing the incidence of EF and ASD, and is a better surgical method.

Mechanical barriers and transforming growth factor beta inhibitor on epidural fibrosis in a rabbit laminectomy model

Background

TGF-β has been described as a mediator of fibrosis and scarring. Several studies achieved reduction in experimental scarring through the inhibition of TGF-β. Fibroblasts have been defined as the cell population originating fibrosis, blocking fibroblast invasion may impair epidural fibrosis appearance. For this purpose, biocompatible materials used as mechanical barriers and a TGF-β inhibitor peptide were evaluated in the reduction of epidural fibrosis.

Methods

A L6 laminectomy was performed in 40 New Zealand white rabbits. Divided into four groups, each rabbit was assigned to receive either collagen sponge scaffold (CS group), gelatin-based gel (GCP group), P144® (iTGFβ group), or left untreated (control group). Four weeks after surgery, cell density, collagen content, and new bone formation of the scar area were determined by histomorphometry. Two experienced pathologists scored dura mater adhesion, scar density, and inflammatory infiltrate in a blinded manner.

Results

In all groups, laminectomy site was filled with fibrous tissue and the dura mater presented adhesions. Only GCP group presented a significant reduction in collagen content and scar density.

Conclusion

GCP treatment reduces epidural fibrosis although did not prevent dura mater adhesion completely.

Electronic supplementary material

The online version of this article (10.1186/s13018-018-0781-6) contains supplementary material, which is available to authorized users.

Evaluation of topical Dexmedetomidine administration in postlaminectomy epidural fibrosis rat model

Epidural fibrosis is a challenging topic in spinal surgery. Numerous clinical and experimental studies have been focused on this issue to clarify problems faced in spinal procedures for the patient as well as the surgeon and find out new methodologies. Dense cytokines and growth factors which are released from inflammatory cells have been suggested to play a major role in the inception and progression of fibrosis. One of the most investigated and important actor in epidural fibrosis is assumed to be the transforming growth factor-1β (TGF-1β) formation. Studies showed that Dexmedetomidine (DEX) downregulates TGF-β pathway with its anti-inflammatory and antioxidant effects. From this point of view, for the first time in the literature we try to observe if there will be an effect of topical DEX administration over epidural fibrosis in a rat model. We hypothesized that DEX might have preventive effects on epidural fibrosis via anti-inflammatory and antioxidant effects. Twenty-four adult male Wistar albino rats were randomly assigned to three groups (Topical DEX, Spongostan, Laminectomy). A total laminectomy was performed at the L3-L5 level and then the ligamentum flavum and epidural fat tissue were cleared away from the surgical site. Histopathological assessment was performed postoperatively after 4 weeks. Our study revealed that topical DEX administration may have effects on reducing epidural fibrosis. Topical DEX administration may be helpful in preventing epidural fibrosis after laminectomy in rats through multiple anti-inflammatory and antioxidant mechanisms as well as through TGF -1β pathway.

Tamoxifen inhibits fibroblast proliferation and prevents epidural fibrosis by regulating the AKT pathway in rats

Many factors contribute to epidural fibrosis after lumbar laminectomy, particularly the excessive proliferation of fibroblasts. Many studies have shown that tamoxifen (TAM) inhibits fibroblast proliferation and reduces fibrosis, but the detailed effect and mechanism of TAM on preventing epidural fibrosis are unknown. To investigate the effect of TAM on fibroblast proliferation and epidural fibrosis, fibroblasts were cultured and treated with different concentrations of TAM. Cell Counting Kit-8(CCK-8) detection, cell cycle analysis and western blot analysis were used to detect the roles of TAM in regulating fibroblast proliferation. Lumbar laminectomies were performed in rats, and various concentrations of TAM were administered by gavage. Histological and immunohistochemical analyses were used to evaluate the effects of TAM on preventing epidural fibrosis. CCK-8 detection showed that TAM could inhibit fibroblast viability; western blot analysis showed that TAM could decrease the expression of proliferative proteins p-AKT and cyclinD1 and increase the expression of antiproliferative proteins P21 and P27. Histological analysis showed that TAM could reduce epidural fibrosis. Immunohistochemical analysis showed that the p-ATK expression in epidural scar tissue was decreased after TAM treatment. The present study demonstrated that TAM could inhibit fibroblast proliferation and prevent epidural fibrosis, potentially through the regulation of the AKT pathway.

Epidural scarring after lumbar disc surgery: Equivalent scarring with/without free autologous fat grafts

Background:

To limit epidural fibrosis and prevent scar formation/nerve tethering that may contribute to chronic postoperative pain; some surgeons have utilized epidural autologous fat grafts following lumbar microdiscectomy.

Methods:

We investigated the correlation between post-microdiscectomy epidural scarring [including select magnetic resonance imaging (MRI) studies] and clinical outcomes in 36 patients operated for symptomatic. MRI documented L4-L5 and L5-S1 disk herniations with (18 patients) and without (18 patient) the application of free fat grafts. In addition, histological evaluation of the original fat grafts was performed in 4 patients requiring additional surgery.

Results:

We found no clear association between the use of autologous graft fats and the clinical outcomes in this study.

Conclusion:

In this preliminary study involving only 36 patients, the prospective randomized use of free autologous fat grafts did not appear to influence outcomes following microdiscectomy.

Tacrolimus induces fibroblasts apoptosis and reduces epidural fibrosis by regulating miR-429 and its target of RhoE

Tacrolimus (FK506) has been demonstrated to reduce epidural fibrosis. However, the detailed mechanism of action has not been elucidated. Aberrant miR-429 is involved in many diseases. The aim of this study was to describe the exact mechanism of FK506 induced apoptosis in fibroblasts and the prevention of epidural fibrosis. FK506 induced fibroblast apoptosis was evaluated using CCK-8 assays, flow cytometry, and western blotting. The expression of miR-429 in fibroblasts treated with FK506 was determined by RT-qPCR. Additionally, luciferase activity assays were used to determine the target relationship between miR-429 and RhoE. Flow cytometry and western blot analysis were used to determine the effects of FK506 and miR-429 on fibroblast apoptosis. The effects of FK506 and RhoE on fibroblast apoptosis were determined by CCK-8 assay, flow cytometry, and western blotting. We also evaluate the effects of FK506 and miR-429 on epidural fibrosis in rats by using histological analysis and TUNEL-staining. The results revealed FK506 induces fibroblast apoptosis and significantly downregulates miR-429 expression in fibroblasts. Additionally, miR-429 downregulation caused the apoptosis of fibroblasts. The luciferase activity assay confirmed that RhoE is a direct target of miR-429 and RhoE promotes fibroblast apoptosis. The rat model demonstrated miR-429 inhibition promotes fibroblast apoptosis and epidural fibrosis, which is consistent with the results of FK506 treatment. Our study demonstrates that FK506 induces fibroblast apoptosis and reduces epidural fibrosis by regulating miR-429 expression and its target of RhoE.

Upregulation of NOXA by 10-Hydroxycamptothecin plays a key role in inducing fibroblasts apoptosis and reducing epidural fibrosis

The fibrosis that develops following laminectomy or discectomy often causes serious complications, and the proliferation of fibroblasts is thought to be the major cause of epidural fibrosis. 10-Hydroxycamptothecin (HCPT) has been proven to be efficient in preventing epidural fibrosis, but the exact mechanism is still unclear. NOXA is a significant regulator of cell apoptosis, which has been reported to be beneficial in the treatment of fibrosis. We performed a series of experiments, both in vitro and in vivo, to explore the intrinsic mechanism of HCPT that underlies the induction of apoptosis in fibroblasts, and also to investigate whether HCPT has positive effects on epidural fibrosis following laminectomy in rats. Fibroblasts were cultured in vitro and stimulated by varying concentrations of HCPT (0, 1, 2, 4 µg/ml) for various durations (0, 24, 48, 72 h); the effect of HCPT in inducing the apoptosis of fibroblasts was investigated via Western blots and TUNEL assay. Our results showed that HCPT could induce apoptosis in fibroblasts and up-regulate the expression of NOXA. Following the knockdown of NOXA in fibroblasts, the results of Western blot analysis showed that the level of apoptotic markers, such as cleaved-PARP and Bax, was decreased. The results from the TUNEL assay also showed a decreased rate of apoptosis in NOXA-knocked down fibroblasts. For the in vivo studies, we performed a laminectomy at the L1-L2 levels in rats and applied HCPT of different concentrations (0.2, 0.1, 0.05 mg/ml and saline) locally; the macroscopic histological assessment, hydroxyproline content analysis and histological staining were performed to evaluate the effect of HCPT on reducing epidural fibrosis. The TUNEL assay in epidural tissues showed that HCPT could obviously induce apoptosis in fibroblasts in a dose-dependent manner. Also, immunohistochemical staining showed that the expression of NOXA increased as the concentrations of HCPT increased. Our findings are the first to demonstrate that upregulation of NOXA by HCPT plays a key role in inducing fibroblast apoptosis and in reducing epidural fibrosis. These findings might provide a potential therapeutic target for preventing epidural fibrosis following laminectomy.

The effect of suramin on inhibiting fibroblast proliferation and preventing epidural fibrosis after laminectomy in rats

Background

Epidural fibrosis often causes serious complications in patients after lumbar laminectomy and discectomy and is associated with the proliferation of fibroblasts. Suramin is known to have an obvious inhibitory effect on the coactions of many growth factors and their receptors, but little was previously known about the effect of suramin on fibroblast proliferation and the progress of epidural fibrosis.

Methods

We illustrated the effect of suramin on cultured fibroblasts of rats with different concentrations (0, 200, 400, 600 mg/l). The proliferation of suramin-treated fibroblasts was evaluated by CCK-8 and western blot analysis. Additionally, in a rat model of laminectomy, different concentrations of suramin (100, 200, and 300 mg/ml) and saline were applied to the laminectomy sites locally. The effect of suramin on preventing epidural fibrosis was detected by the Rydell classification, hydroxyproline content, histological analysis, and collagen density analyses.

Results

The results of CCK-8 shown that suramin could significantly inhibit fibroblasts proliferation in a dose-dependent manner. The western blotting shown that the expression levels of the cell proliferation markers such as cyclin D1, cyclin E, and PCNA were down-regulated. Moreover, in a rat model, we found that suramin could reduce epidural fibrosis as well as inhibit fibroblast proliferation, and 300 mg/ml suramin had better effect.

Conclusions

Topical application of suramin could reduce epidural fibrosis after laminectomy, and the application of suramin could inhibit the proliferation of fibroblasts in rats. This study indicates that suramin is a potent antifibrotic agent that may have therapeutic potential for patients with epidural fibrosis.

Effects of a Temperature-Sensitive, Anti-Adhesive Agent on the Reduction of Adhesion in a Rabbit Laminectomy Model

OBJECTIVE

A common cause of failure in laminectomy surgery is when epidural, peridural, or perineural adhesion occurs postoperatively. The purpose of this study is to examine the efficacy of a temperature-sensitive, anti-adhesive agent (TSAA agent), Guardix-SG®, as a mechanical barrier for the prevention or reduction of peridural scar adhesion in a rabbit laminectomy model.

METHODS

Twenty-six mature rabbits were used for this study. Each rabbit underwent two separate laminectomies at lumbar vertebrae L3 and L6, left empty (the control group) and applied 2 mL of the TSAA agent (the experimental group), respectively. Invasive scar formation or inflammation after laminectomy was quantitatively evaluated by measuring the thickness of the dura, the distance from the surface of dura to the scar tissues, the number of inflammatory cells in the scar tissues at the laminectomy site, and the concentration of collagen in histological sections.

RESULTS

At 6 weeks postsurgery, the dura was significantly thinner and the distance from the surface of dura to the scar tissues was greater in the experimental group than in the control group (p=0.04 and p=0.01). The number of inflammatory cells was not significantly different in the two groups (p=0.08), although the mean number of inflammatory cells was relatively lower in the experimental group than in the control group.

CONCLUSION

The current study suggests that the TSAA agent, Guardix-SG®, could be useful as an interpositional physical barrier after laminectomy for the prevention or reduction of adhesion.

Local application of rapamycin reduces epidural fibrosis after laminectomy via inhibiting fibroblast proliferation and prompting apoptosis

Background

Epidural fibrosis is a common complication after laminectomy. It is associated with intractable lower back pain and additional complications. To date, no study has evaluated whether the local application of rapamycin (RAPA) can inhibit fibroblast proliferation and reduce epidural scar adhesion after laminectomy. The results of the present study showed that the local application of RAPA reduces epidural fibrosis after laminectomy in rats.

Methods

In this study, 32 male Sprague-Dawley rats were randomly divided into four groups (0.2 mg/ml RAPA-treated group, 0.1 mg/ml RAPA-treated group, 0.05 mg/ml RAPA-treated group and physiological saline group). Laminectomy was performed at the level of lumbar segment 1 to 2, and different concentrations of RAPA or saline were applied to the laminectomy sites for 10 min. Four weeks after laminectomy, the rats were sacrificed, and the degrees of epidural adhesion in each group were evaluated. Macroscopic assessment, analysis of hydroxyproline content, and histological analysis were used to determine the therapeutic effect of the local application of RAPA on the inhibition of fibroblast proliferation and the reduction of epidural fibrosis after laminectomy. Next, we cultured fibroblasts from epidural scar tissues of rats that had undergone laminectomy. Fibroblasts were exposed to the indicated concentrations of RAPA, and western blotting and TUNEL assays were used to assess the effects of RAPA on inhibiting fibroblasts proliferation and promoting fibroblast apoptosis.

Results

The results of macroscopic assessments, analysis of hydroxyproline content, and histological analyses indicated that RAPA significantly inhibited fibroblast proliferation and reduced epidural fibrosis in the treated groups in the rat model. The western blotting results indicated that the expression levels of the pro-apoptotic proteins cleaved-PARP and Bax were up-regulated, whereas those of Bcl-2 were reduced. TUNEL assay indicated that the apoptosis rates of fibroblasts were significantly increased after exposure to the indicated concentrations of RAPA.

Conclusions

The local application of RAPA reduced epidural fibrosis after laminectomy by inhibiting the proliferation of fibroblasts, stimulating their apoptosis, and decreasing collagen synthesis. This protocol may be used in new clinical treatment strategies to reduce epidural fibrosis after laminectomy.

Effects of hemostatic polysaccharide agent on epidural fibrosis formation after lumbar laminectomy in rats

BACKGROUND CONTEXT

Epidural fibrosis is a common adverse outcome of spinal surgery that can compress the dural sac and nerve root. Local hemostatic agents have many indications in numerous types of spinal surgery. As these agents may behave as foreign bodies, inducing inflammation and delaying regeneration, they could enhance the risk of epidural fibrosis.

PURPOSE

We evaluated the effects of hemostatic polysaccharide on epidural fibrosis development in laminectomized rats.

STUDY DESIGN

This is a randomized controlled trial.

OUTCOME MEASURES

One month after surgery, tissues were histopathologically examined. Spinal tissue surrounding the laminectomy site was cut with a microtome and stained with hematoxylin and eosin and Masson trichrome. Slides were evaluated by a pathologist in a blinded fashion. The extent of epidural fibrosis, fibroblast cell density, cartilage, and bone regeneration was evaluated.

METHODS

Rats were randomly assigned to receive sham surgery, laminectomy, or laminectomy with hemostatic polysaccharide (seven rats per group). Sham surgery that consisted of a skin incision was performed without laminectomy. Laminectomy was performed at the L1 and L2 vertebrae. In the experimental group, the polysaccharide hemostatic material, HaemoCer was placed in the laminectomy area.

RESULTS

The proportion of rats with epidural fibrosis in laminectomized mice (both with and without hemostatic material) was higher than in sham-operated rats (p<.01). There was no difference in fibrosis between the two groups of laminectomized rats (p>.05).

CONCLUSIONS

Our study indicates that hemostatic polysaccharide does not enhance epidural fibrosis following laminectomy in rodents, suggesting that absorbable polysaccharides may be appropriate for use in hemostasis during spinal surgery.

Epidural Fibrosis after Lumbar Disc Surgery: Prevention and Outcome Evaluation

Study Design

This is a prospective, randomized, controlled study designed and conducted over 10 years from 2002 to 2012.

Purpose

The study aimed to monitor the effect of suction drains (SD) on the incidence of epidural fibrosis (EF) and to test, if the use of SD alone, SD with local steroids application, SD combined with fat grafts and local steroids application, or SD combined with fat grafts and without local steroids application, would improve outcome.

Overview of Literature

EF contributes to significant unsatisfactory failed-back syndrome. Efforts have been tried to reduce postoperative EF, but none were ideal.

Methods

Between September 2002 and 2012, 290 patients with symptomatic unilateral or bilateral, single-level lumbar disc herniation were included in the study. Two groups were included, with 165 patients in group I (intervention group) and 125 patients in group II (control group). Group I was subdivided into four subgroups: group Ia (SD alone), group Ib (SD+fat graft), group Ic (SD+local steroids), and group Id (SD+fat graft+local steroids).

Results

The use of SD alone or combined with only fat grafts, fats grafts and local steroids application, or only local steroids application significantly improved patient outcome and significantly reduced EF as measured by magnetic resonance imaging (MRI).

Conclusions

This study has clearly demonstrated the fact that the use of suction drainage alone or combined with only fat grafts, fats grafts and local steroids application, or only local steroids application significantly improved patient outcome with respect to pain relief and functional outcome and significantly reduced EF as measured by an MRI. A simple grading system of EF on MRI was described.

Evaluation of topical application and systemic administration of rosuvastatin in preventing epidural fibrosis in rats

BACKGROUND CONTEXT

Epidural fibrosis is a major challenge in spine surgery, with some patients having recurrent symptoms secondary to excessive formation of scar tissue resulting in neurologic compression. One of the most important factors initiating the epidural fibrosis is assumed to be the transforming growth factor-1β (TGF-1β). Rosuvastatin (ROS) has shown to demonstrate preventive effects over fibrosis via inhibiting the TGF-1β.

PURPOSE

We hypothesized that ROS might have preventive effects over epidural fibrosis through the inhibition of TGF-1β pathways.

STUDY DESIGN

Experimental animal study.

METHODS

Forty-eight adult male Wistar Albino rats were equally and randomly divided into four groups (laminectomy, spongostan, topical ROS, and systemic ROS). Laminectomy was performed at the L3 level in all rats. Four weeks later, the extent of epidural fibrosis was assessed both macroscopically and histopathologically.

RESULTS

Our data revealed that topical application and systemic administration of ROS both were effective in reducing epidural fibrosis formation. Furthermore, the systemic administration of ROS yielded better results than topical application.

CONCLUSIONS

Both topical application and systemic administration of ROS show meaningful preventive effects over epidural fibrosis through multiple mechanisms. The results of our study provide the first experimental evidence of the preventive effects of ROS over epidural fibrosis.

Reduction of epidural fibrosis and dural adhesions after lamina reconstruction by absorbable cement: an experimental study

BACKGROUND CONTEXT

Post-laminectomy epidural fibrosis complicates revision spine surgery and is implicated in cases of "failed back syndrome." Several materials have been used to minimize epidural fibrosis with varying results.

PURPOSE

The aim of this study was to examine the impact of reconstruction of laminectomy site with a type of absorbable cement (Jectos) to reduce epidural fibrosis.

STUDY DESIGN

This investigation is an experimental controlled study, which is designed to evaluate the preventive effects of laminectomy site reconstruction in rat laminectomy model.

METHODS

Twenty wistar rats were included in this study and divided randomly to two equal groups, namely, subject and control. In both groups, laminectomy was performed in L2 and L4 levels. Control group received no additional treatment. In the subject group, L4 levels were reconstructed by Jectos and L2 levels were non-reconstructed as internal controls. Six months after surgery the rats were sacrificed and the dural adhesion and epidural fibrosis were evaluated macroscopically and microscopically. The study was financially supported by Brain and Spinal Cord Injuries Repair Center. None of the authors have any conflict of interest.

RESULTS

Non-reconstructed levels in both groups showed dense epidural fibrosis with marked dural adherence. L4 reconstructed levels in subject group showed reduced epidural fibrosis macroscopically (p=.024) and microscopically (p=.041). No foreign body reaction or ossification occurred at reconstructed sites.

CONCLUSIONS

In the present study, lamina reconstruction with absorbable cement was a safe method that significantly reduced post-laminectomy epidural fibrosis and dural adhesions in rat laminectomy model.

Use of decorin to prevent epidural fibrosis in a post-laminectomy rat model

The formation of epidural fibrosis adjacent to the dura mater is a complex multi-step process that is associated with a marked reduction in tissue cellularity and the excessive deposition of extracellular matrix components. Extensive epidural fibrosis is a major cause of post-laminectomy syndrome. Decorin strongly inhibits fibrosis formation in various tissues via blockade of transforming growth factor-β1. The aim of this study was to investigate the effects of a topical application of decorin on the formation of epidural fibrosis in a rat laminectomy model. Twenty-four female Wistar albino rats (250-350 g) were equally and randomly divided into three groups (control, spongostan and decorin). Laminectomy was performed between the L3 and L5 levels in all rats. The dura mater was directly exposed to spongostan soaked with saline (2 cc/kg) or decorin (100 µg/kg). Four weeks later, the laminectomized spine of the rats was completely removed between the L3 and L5 levels. The extent of the epidural fibrosis and arachnoidal involvement was histopathologically evaluated and graded. Our data revealed that epidural fibrosis was significantly reduced in the group treated with decorin compared to the spongostan and control groups (P<0.05). Our study demonstrates that the topical application of decorin can be effective in reducing the formation of epidural fibrosis in a simple laminectomy rat model.

All-trans retinoic acid prevents epidural fibrosis through NF-κB signaling pathway in post-laminectomy rats

Laminectomy is a widely accepted treatment for lumbar disorders, and epidural fibrosis (EF) is a common complication. EF is thought to cause post-operative pain recurrence after laminectomy or discectomy. All-trans retinoic acid (ATRA) has shown anti-fibrotic, anti-inflammatory, and anti-proliferative functions. The object of this study was to investigate the effects of ATRA on the prevention of EF in post-laminectomy rats. In vitro, the anti-fibrotic effect of ATRA was demonstrated with cultured fibroblasts count, which comprised of those that were cultured with/without ATRA. In vivo, rats underwent laminectomy at the L1-L2 levels. We first demonstrated the beneficial effects using 0.05% ATRA compared to vehicle (control group). We found that a higher concentration of ATRA (0.1%) achieved dose-dependent results. Hydroxyproline content, Rydell score, vimentin-positive cell density, fibroblast density, inflammatory cell density and inflammatory factor expression levels all suggested better outcomes in the 0.1% ATRA rats compared to the other three groups. Presumably, these effects involved ATRA's ability to suppress transforming growth factor (TGF-β1) and interleukin (IL)-6 which was confirmed with reverse-transcriptase polymerase chain reaction (RT-PCR). Finally we demonstrated that ATRA down-regulated nuclear factor (NF)-κB by immunohistochemistry and western blotting for p65 and inhibition of κB (IκBα), respectively. Our findings indicate that topical application of ATRA can inhibit fibroblast proliferation, decrease TGF-β1 and IL-6 expression level, and prevent epidural scar adhesion in rats. The highest concentration employed in this study (0.1%) was the most effective. ATRA suppressed EF through down-regulating NF-κB signaling, whose specific mechanism is suppression of IκB phosphorylation and proteolytic degradation.

Investigation of efficacy of mitomycin-C, sodium hyaluronate and human amniotic fluid in preventing epidural fibrosis and adhesion using a rat laminectomy model

Study Design

A retrospective study.

Purpose

The aim of this study was to evalute the effects of mitomycin-C, sodium hyaluronate and human amniotic fluid on preventing spinal epidural fibrosis.

Overview of Literature

The role of scar tissue in pain formation is not exactly known, but it is reported that scar tissue causes adhesions between anatomic structures. Intensive fibrotic tissue compresses on anatomic structures and increases the sensitivity of the nerve root for recurrent herniation and lateral spinal stenosis via limiting movements of the root. Also, neuronal atrophy and axonal degeneration occur under scar tissue.

Methods

The study design included 4 groups of rats: group 1 was the control group, groups 2, 3, and 4 receieved antifibrotic agents, mitomycin-C (group 2), sodium hyaluronate (group 3), and human amniotic fluid (group 4). Midline incision for all animals were done on L5 for total laminectomy. Four weeks after the surgery, the rats were sacrificed and specimens were stained with hematoxylin-eosin and photos of the slides were taken for quantitive assesment of the scar tissue.

Results

There was no significant scar tissue in the experimental animals of groups 2, 3, and 4. It was found that there was no significant difference between drug groups, but there was a statistically significant difference between the drug groups and the control group.

Conclusions

This experimental study shows that implantation of mitomycin-C, sodium hyaluronate and human amniotic fluid reduces epidural fibrosis and adhesions after spinal laminectomy in rat models. Further studies in humans are needed to determine the complications of the agents researched.