Laminectomy Defect Research Articles

Comparison of the effectiveness of diclofenac sodium and tenoxicam in the prevention of epidural fibrosis by topical application with an absorbable gelatin sponge on the dura in an experimental laminectomy model.

There has been an increasing trend in spinal surgery interventions in recent years. Low back pain is a disorder that is seen at least once in the lifetime of approximately 80% of the general population. Today, neurosurgeons perform operations including laminectomy for various reasons. Epidural fibrosis is a scar tissue that develops after posterior spinal surgery. Various synthetic and organic materials have been used in experimental studies to prevent epidural fibrosis in laminectomy defects. In this study we aimed to investigate and observe histopathologically the effectiveness of cyclooxygenase inhibitor drugs; tenoxicam and diclofenac sodium in the experimental rat laminectomy model in preventing the postoperative spinal epidural fibrosis. In this study, 32 Wistar-Albino female rats were used. 8 mg/kg tenoxicam and 1.5 mg/kg diclofenac sodium were applied on the dura with an absorbable gelatin sponge. After decapitation, L1-L4 laminectomy area was totally removed and histopathological examination was performed. It has been shown that the topical application of diclofenac sodium and tenoxicam, which are selective Cox inhibitor drugs, prevents fibroblast migration by forming a local barrier and Cox inhibitors are caused by the inhibition of prostanoids, which are inflammatory mediators.

Lumbar Interbody Fusion for Adjacent Segment Disease: An illustrative Case of The Retroperitoneal Anterolateral Psoas-Sparing Approach (Antepsoas; ATP)

Following prior lumbar arthrodesis, surgery for adjacent segment disease (ASD) is not uncommon. Many challenges exist due to scarring, laminectomy defects, retained hardware, and increased risks of various surgical morbidities. These include iatrogenic durotomy, neurologic injuries, wound infections, and ASD recurrence. The minimally invasive retroperitoneal anterolateral psoas-sparing (ATP) approach, unlike the transpsoas and transforaminal techniques, allows access to the T12-S1 segments, enabling unobstructed corridor to discectomy, endplate preparation, anterior column release, direct lumbar decompression, intervertebral height restoration, and sagittal lordosis correction. Despite the promising attributes of the ATP in managing ASD, high quality data is still lacking.

Late-onset recurrence of neurological deficits after surgery for spinal arachnoid diverticula

Spinal cord dysfunction secondary to spinal arachnoid diverticula (SAD) has been widely reported in the veterinary literature and there is some suggestion that surgical treatment may provide better outcomes than...

Magnetic resonance imaging versus computed tomography to plan hemilaminectomies in chondrodystrophic dogs with intervertebral disc extrusion.

To determine the influence of preoperative computed tomography (CT) versus magnetic resonance (MR) on hemilaminectomies planned to treat thoracolumbar (TL) intervertebral disc (IVD) extrusions in chondrodystrophic dogs. Prospective clinical study. Forty chondrodystrophic dogs with TL IVD extrusion and preoperative CT and MR studies. MR and CT images were randomized and reviewed by 4 observers masked to the dog's identity and corresponding imaging studies. Observers planned the location along the spine, side, and extent (number of articular facets to be removed) based on individual reviews of CT and MR studies. Intra-observer agreement was determined between overall surgical plan, location, side, and size of the hemilaminectomy planned on CT versus MR of the same dog. Similar surgical plans were developed based on MR versus CT in 43.5%-66.6% of dogs, depending on the observer. Intra-observer agreement in location, side, and size of the planned hemilaminectomy based on CT versus MR ranged between 48.7%-66.6%, 87%-92%, and 51.2%-71.7% of dogs, respectively. Observers tended to plan larger laminectomy defects based on MR versus CT of the same dog. Findings from this study indicated considerable differences in hemilaminectomies planned on preoperative MR versus CT imaging. Surgical location and size varied the most; the side of planned hemilaminectomies was most consistent between imaging modalities.

Caveats in diagnosis of osteoporosis

Abstract With increasing life expectancy the prevalence of osteoporosis is on rise and it poses a major public health issue. Bone Mineral Density (BMD) measurement by Dual Energy X-ray Absorptiometry (DEXA) is now widely available and is considered as a gold standard. Bone density measured by DEXA is obtained in grams/cm2, but in clinical practice these values are standardized and are expressed as T and Z scores. These scores are used for diagnosis and management of osteoporosis, but assessment with these scores alone is not without pitfalls. Any health care provider without complete awareness of these pitfalls could make an inappropriate diagnosis. Lumbar spine, proximal femur and wrist are the most common sites for BMD assessment. Degenerative changes a spine or hip, healed fractures, avascular necrosis, benign or metastatic bone forming lesions present as a false positive increase in BMD, while laminectomy defects and lytic lesions result in false negative decrease in BMD. Also the scores are dependent on age, gender, race and the machine used. Thus for follow up, it is important use the same scanner with same software version. In case of any discrepancy, it is necessary to compare the raw BMD values.

Surgical management of recurrent disc herniations with microdiscectomy and long-term results on life quality: Detailed analysis of 70 cases.

Background:Aim of this paper is to recall the surgical technique used in the recurrent lumbar disc herniations (LDHs) and to share our experiences.Materials and Methods:Out of series of 1115 patients who underwent operations for LDH between 2006 and 2013, 70 patients underwent re-operations, which were included in this study. During surgery, lateral decompression performed over the medial facet joint to the superior facet joint border was seen after widening the laminectomy defect, and microdiscectomy was performed. The demographic findings of the patients, their complaints in admission to hospital, the level of operation, the condition of dural injury, the first admission in the prospective analysis, and their quality of life were evaluated through the Oswestry scoring during their postoperative 1st, 3rd, 6th-month and 1st, 3rd, 5th and 7th-year follow-up. In the statical analysis, Friedman test was performed for the comparison of the Oswestry scores and Siegel Castellan test was used for the paired nonparametrical data. A P < 0.05 was considered statistically significant.Results:Considering the Oswestry Index during the follow-ups, the values in the postoperative early period and follow-ups were seen to be significantly lower than those at the time of admission to hospital (P < 0.05). None of the patients, who re-operated by microdiscectomy, presented with iatrogenic instability in 7 years follow-up period.Conclusion:Microdiscectomy performed through a proper technique in the re-operation of recurrent disc herniations eases complaints and improves the quality of life. Long-term follow-ups are required for more accurate results.

The use of autologous neurogenically-induced bone marrow-derived mesenchymal stem cells for the treatment of paraplegic dogs without nociception due to spinal trauma.

The aim of this study was to investigate the effects of percutaneous transplanted autologous neurogenically-induced bone marrow-derived mesenchymal stem cells (NIBM-MSCs) in paraplegic dogs without deep pain perception (DPP) secondary to external spinal trauma. Thirteen client owned dogs that had failed in improvement neurologically at least 42 days after conservative management, decompression and decompression-stabilization were included in the study. Each dog received two doses of autologous 5.0 × 106 NIBM-MSCs suspension, which were positive to 2′,3′-Cyclic-nucleotide-3′-phosphodiesterase (CNPase) and Microtubule-associated protein 2 (MAP-2), as well as to Glial fibrillary acidic protein (GFAP) and beta III tubulin. The cells were injected into the spinal cord through the hemilaminectomy or laminectomy defects percutaneously with 21 days interval for 2 times. The results were evaluated using Texas Spinal Cord Injury Scale (TSCIS), somatosensory evoked potentials (SEP) and motor evoked potentials (MEP) at the admission time, cell transplantation procedures and during 2, 5, 7 and 12th months after the second cell transplantation. Improvement after cell transplantation in gait, nociception, proprioception, SEP and MEP results was observed in just 2 cases, and only gait score improvement was seen in 6 cases, and no improvement was recorded in 5 cases. All progresses were observed until 2nd month after the second cell transplantation, however, there was no improvement after this period. In conclusion, percutaneous transplantation of autologous NIBM-MSCs is a promising candidate modality for cases with spinal cord injury after spinal trauma and poor prognosis.

An injectable hydrogel with or without drugs for prevention of epidural scar adhesion after laminectomy in rats

Epidural scarring occurs inevitably in the defect after spinal laminectomy, and thus how to prevent or reduce it becomes a challenging topic. In the present study, an injectable hydrogel and its dexamethasone (DEX)-loaded hydrogel systems were adopted to prevent epidural scarring in a postlaminectomy rat model. The hydrogel system composed of poly(D,L-lactic acid-co-glycolic acid)-poly(ethylene glycol)-poly(D,L-lactic acid-co-glycolic acid) (PLGA-PEG-PLGA) triblock copolymers was a free-flowing sol at room temperature, and spontaneously turned into a semi-solid gel at body temperature. A lumbar 3 total laminectomy was performed on Sprague Dawley (SD) rats, and the efficacy of the injectable hydrogel with or without drugs in preventing epidural scar formation was evaluated via the gross anatomical observation and histological examination at one month post-surgery. The results demonstrate that the use of hydrogel alone reduced epidural scarring significantly, whereas the efficacy of the DEX-loaded hydrogels presented an irregular dose-dependency of drug and even the inappropriate drug doses resulted in the negative results. Therefore, the present study confirms that the PLGA-PEGPLGA hydrogel holds potential as a barrier device to decrease peridural scarring, and reveals that the sustained delivery of the steroid hormone DEX to prevent surgery-related adhesions in the laminectomy defect is complex. Moreover, our in vivo studies also remind the researchers to pay attention to the irregular dose-dependency of the hormone drugs.

Preliminary documentation of the comparable efficacy of vitoss versus NanOss bioactive as bone graft expanders for posterior cervical fusion.

Background:Laminectomies with posterior cervical instrumented fusions often utilize bone graft expanders to supplement cervical lamina/iliac crest autograft/bone marrow aspirate (BMA). Here we compared posterior fusion rates utilizing two graft expanders; Vitoss (Orthovita, Malvern, PA, USA) vs. NanOss Bioactive (Regeneration Technologies Corporation [RTI: Alachua, FL, USA]).Methods:Two successive prospective cohorts of patients underwent 1-3 level laminectomies with 5-9 level posterior cervical fusions to address cervical spondylotic myelopathy (CSM) and/or ossification of the posterior longitudinal ligament (OPLL). The first cohort of 72 patients received Vitoss, while the second cohort or 20 patients received NanOss. Fusions were performed utilizing the Vertex/Rod/Eyelet System (Medtronic, Memphis, TN, USA) with braided titanium cables through the base of intact spinous processes (not lateral mass screws) cephalad and caudad to laminectomy defects. Fusion was documented by an independent neuroradiologist blinded to the study design, utilizing dynamic X-rays and two dimensional computed tomography (2D-CT) studies up to 6 months postoperatively, or until fusion or pseudarthrosis was confirmed at 1 year.Results:Vitoss and NanOss resulted in comparable times to fusion: 5.65 vs. 5.35 months. Dynamic X-ray and CT-documented pseudarthrosis developed in 2 of 72 Vitoss patients at one postoperative year (e.g. bone graft resorbed secondary to early deep wound infections), while none occurred in the 20 patients receiving NanOss.Conclusion:In this preliminary study combining cervical laminectomy/fusions, the time to fusion (5.65 vs. 5.35 months), pseudarthrosis (2.7% vs. 0%), and infection rates (2.7% vs. 0%) were nearly comparable sequentially utilizing Vitoss (72 patients) vs. NanOss (20 patients) as bone graft expanders.

Cervical Laminectomy Width and Spinal Cord Drift Are Risk Factors for Postoperative C5 Palsy

Cervical laminectomy and fusion (CLF) is a treatment option for multilevel cervical spondylotic myelopathy. Postoperative C5 nerve palsy is a possible complication of CLF. It has been suggested that C5 nerve palsy may be due to posterior drift of the spinal cord related to a wide laminectomy trough. To test the hypothesis that excessive spinal cord drift into a wide laminectomy trough is associated with C5 palsy. Retrospective case-control study. Seventeen patients with C5 palsy, 8 patients as control group. Spinal cord positional measurements on magnetic resonance imaging (MRI). All patients who underwent elective CLF for cervical spondylotic myelopathy or ossified posterior longitudinal ligament using posterior instrumentation between 2004 and 2008 were included. Patients who underwent CLF for trauma, infection, or tumors were excluded. Clinical and radiographic outcomes were assessed by chart review (minimum of 1 y follow-up). Patients who developed a new postoperative C5 nerve palsy underwent repeat MRI. The control group also underwent CLF, did not develop a neurological deficit, and received a postoperative MRI for evaluation of possible infection. MRI measurements included the width of the laminectomy trough, the distance from the posterior vertebral body or disk to the anterior spinal cord, the width of the spinal cord herniated into the laminectomy defect, and C2-7 sagittal alignment. Preoperative radiographic measurements included preoperative vertebral body diameter, spinal canal diameter, and sagittal vertical offset. There were seventeen patients with C5 nerve root palsy and 8 patients without C5 nerve root palsy. There were no baseline differences in fusion levels, instrumentation used, patient age, or sex. MRI measurements revealed an increase in mean postoperative cord drift in patients with C5 palsy at C3 (4.2 vs. 2.2 mm, P=0.002), C4 (4.6 vs. 2.8 mm, P=0.056), C5 (5.1 vs. 2.4 mm, P=0.011), and C6 (5.2 vs. 2.4 mm, P=0.003). There was a significant increase in C5 laminectomy trough width among patients with postoperative C5 palsy (17.9 vs. 15.2 mm, P=0.032), but there was no difference in sagittal alignment. A wider laminectomy at C5 was associated with an increased risk of postoperative C5 palsy. Increased preoperative spinal canal diameter is also associated with increased risk of C5 palsy. In addition, patients who experienced C5 nerve palsy had a significantly greater posterior spinal cord drift. Strategies to reduce postoperative laminectomy trough width and spinal cord drift may reduce the risk of postoperative C5 palsy.

Dynamic MRI Reveals Soft-Tissue Compression Causing Progressive Myelopathy in Postlaminectomy Patients: A Report of Three Cases.

Cervical spondylotic myelopathy has been reported as the most common cause of spinal cord dysfunction in individuals older than age fifty-five, although the rate of occurrence is blurred by the difficulty of making a precise and timely diagnosis. The symptoms that patients present with can be inconsistent and show high variability from patient to patient1-4. Magnetic resonance imaging (MRI) has been a beneficial tool for evaluating anteroposterior sagittal diameter, the compression ratio, and the canal-occupying ratio5,6. According to numerous biomechanical and cadaveric studies, cervical flexion results in tension forces on the spinal cord and can cause ventral spinal cord compression against osteophytes and discs. In neck extension, the cervical cord shortens, and there is an increase in the cross-sectional area of the anteroposterior diameter of the spinal cord. In addition, the space available to the spinal cord is reduced as the ligamentum flavum folds inward7,8. We report three cases of progressive myelopathy. The first patient had undergone a previous multilevel cervical laminectomy. Although an initial MRI with the neck in the neutral position showed no spinal cord compression, the patient subsequently underwent dynamic MRI with the neck in extension, which revealed flattening of the spinal cord by soft tissues buckling into the laminectomy defect. The second patient had undergone a previous cervical laminectomy and arthrodesis with lateral mass internal fixation. He presented with progressive myelopathy and exhibited cord flattening on extension MRI, similar to that seen in the first patient. The third patient presented with myelopathic symptoms, had undergone a prior multilevel laminectomy, and had been followed for a syrinx; a cervical MRI with the neck in extension revealed severe stenosis. All three patients were informed that data concerning their cases would be submitted for publication, and they …

Reconstruction of epidural fat with engineered adipose tissue from adipose derived stem cells and PLGA in the rabbit dorsal laminectomy model

Epidural fibrosis resulted from epidural fat destruction following laminectomy operation is regarded as a main cause of failed back surgery syndrome, which represents one of the most common complications in spine surgery. Up to now, the effectiveness of currently available treatments to prevent such a syndrome is quite limited. In the present study, we aimed to restore epidural fat using adipose tissue engineered from adipose derived stem cells (ASCs) in a rabbit dorsal laminectomy model. ASCs isolated from subcutaneous fat were first expanded to passage 3, seeded on porous poly(lactic-co-glycolic acid, PLGA) scaffold and then adipogenically induced for 7 days in vitro to form cell–scaffold complex. Laminectomy sites were created at T13–L1 level in each animal. The laminectomy defect was implanted either with cell–scaffold complex or PLGA scaffold alone. Non-treated defect was also included as a control. The animals were subjected to MRI evaluation at 1, 12 and 24 weeks post-surgery, and sacrificed at 24 weeks for gross and histological observation. It was demonstrated by MRI evaluation that scar tissue of coarse and high density was formed within laminectomy site in PLGA alone and non-treated groups as early as 12 weeks. However, the defect implanted with engineered adipose had formed a continuous linear adipose tissue regenerated along the spinal cord at 24 weeks. Histologically, a distinct area of adipose tissue just overlaying the dura mater could be identified in cell–scaffold complex treated group at 24 weeks post-operation. Regeneration of epidural fat was further confirmed by positive Oil Red O staining. As to the defect treated with PLGA alone or left untreated, either fine or dense scar tissue adhering to the dura mater was observed. Moreover, we could track the implanted ASCs labeled by magnetic nanoparticles within epidural area for as long as four weeks by MRI detection. Thus, adipose tissue engineered from ASCs exhibited great potential in restoration of epidural fat to prevent formation of epidural fibrosis.

The Utility of Bone Cement to Prevent Lead Migration With Minimally Invasive Placement of Spinal Cord Stimulator Laminectomy Leads

Lead migration is a significant concern with spinal cord stimulator (SCS) placement with rates ranging from 10% to 60%. To describe a novel technique using bone cement at the laminotomy site to help prevent lead migration after minimally invasive placement of laminectomy paddle leads and to present our short-term results. A review of a prospectively maintained database identified all patients who underwent minimally invasive placement of laminectomy leads with the use of bone cement. All procedures were performed between July 2008 and August 2010 with conscious sedation and local anesthetic. Intraoperative testing was performed to confirm good pain coverage. A small volume of bone cement (1-3 cm) was then placed to cover the laminectomy defect. Radiographic and clinical follow-up was assessed. Forty-two patients (mean age, 58.0 years) underwent 42 procedures. Back pain (88.1%) and leg pain (88.6%) were the most common presenting symptoms. No intraoperative complications were noted. Two patients (4.8%) required removal of their devices because of nonhealing wounds. All patients were followed up for a minimum of 6 months, and no cases of clinical or radiographic lead migration were seen at the time of publication. We present a novel technique in the hopes of decreasing the incidence of lead migration after minimally invasive placement of spinal cord stimulator laminectomy paddle leads. Our results have been promising thus far with no cases of lead migration.

A bilateral myocutaneous trapezius advancement flap to cover a cervical laminectomy defect

A bilateral myocutaneous trapezius advancement flap to cover a cervical laminectomy defect

Inhibition Of Tumor Necrosis Factor May Improve Wound Healing And Reduce Scar Formation Following Laminectomy. A Pilot Study In Pigs.

In rats treated with a selective TNF-inhibitor it was accidentally found that wound healing was improved and scar/adhesion formation was reduced. The present pilot study was performed to evaluate if this could be repeated in a controlled setting using a laminectomy model in the pig. Following anesthesia a laminectomy of all sacral vertebrae was performed in 6 pigs. Three pigs were treated with infliximab (a selective TNF inhibitor) and three pigs received saline and served as control. After 7 days the laminectomy site was evaluated by a macroscopical analysis and specimens of skin and muscle tissue over the laminectomy were processed for histology. Skin, fascia, muscle and bone healing was remarkably better in the pigs treated with infliximab. In pigs treated with infliximab there were signs of a partial healing of the laminectomy defect and in the centre of the defect there was a gel-like tissue that allowed for observation of the underlying nervous tissues. The laminectomy defect in saline treated animals had less bone formation and a soft scar in the centre of the defect. The present pilot investigation may thus indicate that an inhibition of pro-inflammatory cytokines may increase wound-healing rate and reduce scar formation/adhesion. However, further studies that evaluate exact mechanisms, when and how long to use anti-inflammatory treatment, long term effects, wound quality, risks for infection, if this may be translated to humans, must be undertaken before any conclusions regarding a clinical use may be drawn. The study nevertheless implies that it might be possible to develop a biological agent that alone or in combination with a mechanical barrier may reduce epidural scarring following spinal surgery.

A mass after discectomy, what can it be?

A 28-year old young man presented with a complaint of low-back pain. He had had this problem for 2 years, and the pain had been radiating to his left calf for 4 months. The patient had undergone surgery for lumbar disc herniation 3 months prior to presentation. Physical examination indicated good health status. There was erythema and discharge at the incision site without tenderness and swelling. The straight leg-raising test was positive at near to 80° on the left. The patient's left hamstring muscle strength was 4/5, and he had normal patellar deep tendon reflex on that side. Routine laboratory testing (complete blood count, erythrocyte sedimentation rate, blood biochemistry panel) revealed nothing abnormal. Magnetic resonance imaging (MRI) of the lumbosacral spine showed a laminectomy defect at L4 up to S1 and a mass lesion in the posterior paravertebral region at L5 level. The mass appeared as hypointense spinal cord tissue on T1-weighted images and hyperintense on T2-weighted images. Injection of contrast medium revealed an enhanced hyperintense rim around a hypointense center (Figs 1, 2, 3, 4 MRI images revealing an enhanced hyperintense rim around a hypointense center). What is the most probable diagnosis? (see page 138) A mass after discectomy, what can it be?

Reduction in postlaminectomy epidural adhesions in sheep using a fibrin sealant‐based medicated adhesion barrier

Epidural adhesion formation is believed to be a central governing factor in the prevalence of pain after spinal surgery and is regarded as being the primary instigator of neural tethering, leading to complications during revision surgery. In this study, we assess the effectiveness and safety of fibrin sealant supplemented with tributyrin, termed Medicated Adhesion Barrier (MAB), as an alternative means of reducing the incidence of posterior spinal epidural adhesion formation. Laminectomy defects in sheep were treated with MAB, fibrin sealant alone, ADCONGel, or remained untreated. At 12 weeks postoperatively, the extent of fibrosis and epidural adhesion formation was evaluated using magnetic resonance imaging (MRI), peel-off testing, and histological examination. Initial invitro analysis revealed that tributyrin was retained in fibrin gel in a time-dependent manner and was an effective inhibitor of fibroblast proliferation. Treatment of sheep with MAB significantly reduced both the prevalence (p < 0.05) and tenacity (p < 0.05) of epidural adhesions. The effectiveness of MAB in preventing epidural adhesions was found to be comparable with that of ADCONGel. No adverse events were reported after the use of MAB. The MAB preparation seems to be an effective resorbable barrier for the prevention of epidural adhesions.

Reduction of Postoperative Spinal Implant Infection Using Gentamicin Microspheres

Three noncontiguous spinal implant sites in 1 rabbit were challenged with Staphylococcus aureus and local antibiotic prophylaxis was given with gentamicin in controlled-release microspheres (poly(lactic-coglycolic-acid) [PLGA]). Postoperative biomaterial-centered infection on and around the titanium rods was assessed using standard bacterial quantification essays. To assess surgical site and biomaterial-centered infection reduction with controlled release gentamicin from microspheres against S. aureus. A postoperative biomaterial-centered infection can be devastating after successful thoracolumbar spinal surgery and puts a high burden on patients, families, surgeons, and hospitals, endangering both our healthcare budget and our ability to perform challenging cases in patients with increasing numbers of comorbidities. Systemic antibiotics often do not reach "dead-space" hematomas where bacteria harbor after surgery, whereas local, controlled release gentamicin prophylaxis through PLGA microspheres showed favorable pharmacokinetics data to achieve local bactericidal concentrations for up to 7 days after surgery. A well published rabbit spinal implant model with systemic cephalosporin prophylaxis was challenged to create a baseline infection of approximately 70% in control sites. We then challenged 3 noncontiguous titanium rods inside the laminectomy defect with 10e6 colony forming units S. aureus and randomly treated 2 sites with gentamicin PLGA microspheres and 1 site with PLGA carrier only (control). Standard quantification techniques were used to assess biomaterial centered and soft tissue bacterial growth after 7 days. After establishing reliable infection rates in control sites, the therapeutic arm of the study was started. Surgical site infections were found in 75% of control sites, whereas gentamicin microspheres reduced the incidence down to 38% in the same rabbits. Biomaterial-centered infection was reduced from 58% to 23% only in all sites challenged with 10e6 S. aureus. Postoperative, biomaterial-centered infection was reduced at least 50% with intraoperative gentamicin microspheres in the face of systemic cephalosporin prophylaxis and high dose S. aureus in a laminectomy defect in rabbits. The data are statistically and clinically significant, and further animal testing is planned to confirm these results.

Comparison of a Caprolactone/Lactide Film (Mesofol) to Two Polylactide Film Products as a Barrier to Postoperative Peridural Adhesion in an Ovine Dorsal Laminectomy Model

Experimental study. To evaluate and compare the performances of 2 bioresorbable products, Mesofol (a caprolactone/lactide film) and Lactosorb (a polylactide film), as barriers to postoperative peridural adhesions and fibrosis. Postoperative peridural adhesions from scar tissue may be an inciting cause of chronic pain and dysfunction in "failed back" syndrome. Many biocompatible products and drugs, as well as autografts have been tested as antiadhesion barriers with varying success. The bioresorbable film products were used to cover large laminectomy defects in 11 sheep. Three laminectomy defects were created, with 2 randomly assigned treatment sites and 1 control site in each animal. A tear was created in the dura allowing cerebrospinal fluid leakage to assess for impaired dural healing. Performance of the film barriers was assessed at 10 weeks postoperative by gross scar and tenacity scoring by 3 blinded, independent observers in 7 animals. Histology was performed in 4 animals. New Methylene blue dye myelography and magnetic resonance imaging were performed to assess for cerebrospinal fluid leakage. Magnetic resonance imaging was also used to evaluate the imaging characteristics of adhesions. All 3 products evaluated showed a benefit to prevention of postoperative peridural adhesion; the performance of Mesofol was deemed superior to either of the 2 Lactosorb products. The handling characteristics of all products were compatible with clinical usage. Impairment to healing of dural tears or active inflammation was not identified with any product. The results of this investigation support previous studies on the benefit of polylactide film barriers, like Lactosorb, for reducing peridural adhesion following spinal surgery. The performance of Mesofol in this investigation suggests that it may provide improved antiadhesion properties in comparison to the polylactide products. Safety issues related to impaired dural healing was not identified in either product.

Topical high molecular weight hyaluronan reduces radicular pain post laminectomy in a rat model

Topical high molecular weight hyaluronan reduces radicular pain post laminectomy in a rat model