Positive Effect of Platelet-Rich Plasma on Neoureterocystostomy in Rats: An Experimental Study.

OBJECTIVES: Some of the most common problems after kidney transplant are urologic complications, including ureterocystoanastomosis leakage and stenosis with the development of severe renal graft complications. Isolated plasma contains active substances that cause the activation of various growth factors for the processes of tissue repair or regeneration, has an anti- inflammatory effect, activates angiogenesis, and reduces the risk of infectious complications. Platelet-rich plasma is actively used to stimulate bone regeneration, heal wounds and ulcers on the skin, enhance reconstruction of the larynx and trachea, and ameliorate urethral damage, among other uses. This study was developed to evaluate the positive effect of platelet-rich plasma on the healing process of an anastomotic wound in a model of ureterocystoanas-tomosis in rats. MATERIAL AND METHODS: We randomized 14 Wistar albino male rats into 2 groups: group 1 included 7 rats that received platelet-rich plasma after ureterocystostomy; group 2 was the control group and included 7 rats that underwent ureterocystostomy without platelet-rich plasma. On postoperative day 7, all animals were euthanized, and the anastomosis area was resected for determination of the tissue hydroxyproline levels and histopathology examination. RESULTS: Tissue hydroxyproline levels were 767 ± 62.9 µg/g in group 1 and 256 ± 28.0 µg/g in group 2. Tissue hydroxyproline levels were significantly higher in group 1 compared with group 2 (P < .05). There were no significant differences in epithelial damage, acute inflammation, or fibrosis between the tissue samples of both groups. CONCLUSIONS: The results of this study show that the use of platelet-rich plasma during ureterocystostomy produces a positive effect. Our further research will be devoted to the use of autologous platelet-rich plasma in ureterocystostomy in big models.

Association between focal adhesion kinase and matrix metalloproteinase-9 expression in prostate adenocarcinoma and their influence on the progression of prostatic adenocarcinoma.

Focal adhesion kinase (FAK), a member of the non-receptor cytoplasmic tyrosine kinase family, is associated with the development and progression of cancer. Matrix metalloproteinase-9 (MMP-9) is directly involved in the degradation of the extracellular matrix, and basement membrane components promote cancer cell migration and invasion. There is a functional interaction among FAK, MMP-9 and vascular endothelial growth factor (VEGF), which leads to enhanced cancer angiogenesis, cancer cell invasion and progression of malignancy. FAK, MMP-9, VEGF and CD34-positive microvessel density (MVD) were examined in 100 patients with prostate adenocarcinoma using immunohistochemistry. The relationship among these proteins and their impact on angiogenesis and clinicopathological parameters were also evaluated. The FAK expression was found to be positively correlated with the Gleason score, WHO grade group, tumour stage, extracapsular extension and perineural invasion. The MMP-9 expression was positively correlated with the WHO grade group, tumour stage, extracapsular extension, positive surgical margin and lymphovascular and perineural invasion. The FAK expression was also positively correlated with MMP-9 expression and MVD. However, no correlation between FAK and VEGF expression was identified. The MMP-9 expression was positively correlated with FAK expression and MVD. Strong MMP-9 expression was associated with shorter disease-free survival. These results suggest that strong MMP-9 and FAK expressions play an essential role in the progression of prostate adenocarcinoma. Further investigations should be conducted to determine the importance of these proteins as therapeutic targets for patients with prostate adenocarcinomas.

Microsatellite Instability in Glioblastoma: Is It Really Relevant in Tumor Prognosis?

AIM: To evaluate the frequency and prognostic significance of microsatellite instability (MSI) in patients with glioblastoma (GBM), an immunohistochemical analysis of mismatch repair (MMR) proteins was performed. MATERIAL AND METHODS: A total of 71 patients with GBM who underwent surgery between 2011 and 2019, were included in the study. MMR protein expression was examined using immunohistochemistical analysis of tumor tissue samples; the association between the MMR status and clinicopathological findings was evaluated. RESULTS: Immunohistochemical analysis revealed expressions of MLH1, MSH2, MSH6, and PMS2 proteins in 67 (94.4%), 65 (91.5%), 67 (94.4%), and 64 (90.1%) patients, respectively. Among the 71 patients, 64 (90.1%) expressing all MMR proteins were considered microsatellite stable (MSS), and 7 (9.9%) patients showing loss of at least one of the MMR proteins were considered to show MSI. Tumor recurrence was noted in 25 (39.1%) patients in the MSS GBM group, and 4 (57.1%) patients in the MSI GBM group (p=0.433). The overall median survival was 30.65 ± 5.1 and 10.71 ± 5.2 months in the MSS GBM and MSI GBM groups, respectively (p=0.059). CONCLUSION: The results of this study showed no significant relationships between MMR protein expression and recurrence rates or overall survival in patients with GBM.

When abdominal pain knocks the door: an unusual presentation of chronic lymphocytic leukemia.

A 67-year-old man presented non-specific abdominal pain. Polypoid mass at appendiceal orifice in the cecum was found on endoscopic investigation without appendicitis sign. Histopathology elucidated underlying mucosal infiltration that was chronic lymphocytic leukemia. This is an isolated and unusual gastrointestinal involvement of hematologic disorder in an older patient.

Evaluating the Effects of a Topical Preparation with Dexpanthenol, Silbiol, Undecylenic Acid, and Lidocaine on Palatal Mucosa Wound Healing in a Rat Model

Background: Postoperative complications occur after periodontal plastic surgeries, but an ideal treatment to overcome them has not been found yet. Aims: To evaluate the effects of topically applied Oral-norm gel on the healing of excisional wounds. Study Design: Animal experiment. Methods: Excisional wounds with a diameter of 3 mm were made in the center of the palatal mucosa of 63 Sprague Dawley rats. Seven animals were sacrificed at time 0. The remaining rats were divided into two groups: a test group in which the topical Oral-norm gel was applied three times a day and a control group in which nothing was applied. Seven animals in each group were sacrificed at 3, 7, 14, and 21 days. Mean wound surface area was measured photographically, while wound healing and width were evaluated microscopically. Results: The mean wound surface area decreased significantly after 3 days in both groups (p<0.001). Between days 3 and 7, the mean wound surface area decreased from 6.62 (2.85) to 0.83 (1.62) mm2 in the control group and 5.07 (0.88) to 1.42 (1.67) mm2 in the test group. The wound width decreased significantly on day 7 in both groups (p<0.001), with no further changes by day 14. Both groups had a significant increase in inflammation and vascularization on day 3 (p<0.001), with a reduction thereafter. No significant differences in macroscopic and microscopic measurements were observed between the groups at any time point (p>0.05). Conclusion: The Oral-norm gel has no positive healing effects in the palatal mucosa of rats.

Pretransplant Renal Arterial Vasculopathy of Donor Predicts Poor Renal Allograft Survival.

OBJECTIVES: Transplant vasculopathy is a significant predictor of poor outcome. We investigated whether age or pretransplant renal arterial vasculopathy of grafted kidneys affected allograft survival. MATERIALS AND METHODS: This study included 148 recipients and their donors. All donors underwent pretransplant renal arterial biopsy, with renal artery vascular score determined for each artery. Chronic rejection and graft loss were noted for all patients. RESULTS: Variable grades of pretransplant renal arterial lesions were noted in 103 donors (69.6%). A positive correlation was found between donor age and renal artery score (r = 0.650, P < .001), and chronic rejection and graft loss were found to increase with increasing score (P < .001). Recipient and donor age was significantly associated with graft loss and chronic rejection. With either younger or older donors, recipients had similar and best results regarding chronic rejection and graft loss if donors had renal artery scores of 0 or 1, but worse effects if donors had scores of 2 or 3. Five-year allograft survival rates for scores of 0, 1, 2, and 3 were 91%, 68%, 46%, and 33%. Univariate analyses showed that acute rejection episode (relative risk: 2.729, 95% confidence interval, 1.496-4.977; P = .001), older (? 50 y) donor age (relative risk: 1.970, 95% confidence interval, 1.038-3.736; P = .04), and donor renal artery score (relative risk: 2.466, 95% confidence interval, 1.382-4.401; P = .002) were associated with decreased allograft survival. Multivariate Cox analysis showed that only acute rejection episode (relative risk: 3.585, 95% confidence interval, 1.781-7.217; P < .001) and renal artery score (relative risk: 2.642; 95% confidence interval, 1.355-5.150; P = .004) were independent predictors of allograft survival. CONCLUSIONS: Pretransplant vasculopathy in donor renal artery implies a poor prognosis for renal allograft survival and is independent of other risk factors. Pretransplant renal artery biopsy is recommended for both deceased and living donors, and therapeutic interventions to modify transplant vasculopathy progression should start early posttransplant in recipients with affected renal arteries.

Solid Liver Lesions in an Infant With Neonatal Cholestasis: Is it Always Malignant?

In this report we describe a patient with neonatal cholestasis who was found to have a liver lesion with suspicious imaging features, although ultimately it was histologically proved to be a pseudotumor. We discuss the characteristic features and imaging findings of macroregenerative nodules of the liver.

Primary small intestinal non-Hodgkin lymphoma diagnosed after emergency surgery.

BACKGROUND: The aim of this study was to investigate clinical manifestation, diagnosis, treatment, and prognosis of patients with primary gastrointestinal non-Hodgkin lymphoma (PGI NHL), whose initial presentation was bowel obstruction or perforation. METHODS: Data of patients who underwent surgical intervention due to radiological evidence of perforation or intestinal obstruction and were subsequently diagnosed with intestinal lymphoma at Baskent University hospitals between January 2007 and November 2014 were examined retrospectively. Medical records, clinical history, symptoms, pathological reports, and treatment modalities were analyzed. RESULTS: Study population comprised 17 patients (8 male, 9 female) with PGI NHL and mean age of 52±20.2 years. Symptoms reported by the patients were abdominal pain, nausea, vomiting, weight loss, and loss of appetite. All 17 patients underwent surgical treatment; 12 also received postoperative chemotherapy. Most common pathological subtype was diffuse large B-cell lymphoma (70.5%). Mean follow-up time was 26 months (range: 1-69 months) and 5-year survival rate was 64.3%. CONCLUSION: Initial presentation of PGI NHL may be obstruction with or without perforation; clinicians and surgeons should keep this in mind while assessing patient with bowel obstruction, and particularly patient in fifth decade of life.

Importance of Liver Biopsy Findings on Prognosis of Kidney Transplant Patients.

OBJECTIVES: Chronic hepatitis infection among kidney transplant recipients is not infrequent, with those with hepatitis C virus infection having worse survival. Here, we evaluated liver biopsy changes and its effects on prognosis in kidney transplant recipients. MATERIALS AND METHODS: Patients with liver biopsies were selected from 1275 kidney transplant recipients who were treated at Baskent University from January 1990 to December 2012. Demographic and clinical findings were evaluated, including age, sex, liver biopsy findings, amyloid and hemosiderin accumulation, and patient survival. RESULTS: Among 1275 renal transplant patients, only 149 patients had liver biopsies. Of 149 patients, 68 patients (45.3%) had liver biopsy only before and 81 patients had liver biopsy after transplant, with 20 of the 81 patients also having biopsy before transplant. The 81 patients who had a liver biopsy after renal transplant were included in the study. In our patient group, mean follow-up was 166 ± 29 months, female-to-male ratio was 26/55, and mean age was 30.2 ± 9.87 years (range, 15-56 y). Only 2 of 81 liver biopsies (2.4%) were diagnosed as normal or nonspecific. Biopsy findings of the remaining 79 patients (97.6%) showed variable pathologies, including hepatocellular damage and minimal cholestatic changes in 29 patients (35.8%), chronic nonviral hepatitis in 9 (11.1%), and viral hepatitis in 41 (50.6%). The mean time between the first liver biopsy taken before transplant and second biopsy after transplant was 44.5 ± 38.0 months (range, 11-139 mo). Among 81 patients, 6 (7.4%) showed amyloid deposition and 13 (16.0%) showed hemosiderosis. CONCLUSIONS: Testing for viral infections is critical in transplant recipients. It is well known that these infections can affect the frequency of rejection episodes and also negatively affect survival in solidorgan transplant recipients. Livers should be evaluated by biopsy even if the variance in liver enzymes or serology is minimal.

Posttransplant Lymphoproliferative Disorder Manifesting as Intestinal Epstein-Barr Virus-Positive Anaplastic Large-Cell Lymphoma in an Adult Renal Transplant Recipient.

Posttransplant lymphoproliferative disorder is a relatively common posttransplant malignancy affecting as many as 10% of all solid-organ recipients. Most cases of posttransplant lymphoproliferative disorder are of B-cell origin, with common Epstein-Barr virus association. Posttransplant lymphoproliferative disorders of T-cell origin are much rarer and less frequently associated with Epstein-Barr virus. Here, we report an unusual case of Epstein-Barr virus-positive anaplastic large-cell lymphoma causing an intestinal perforation in an adult renal transplant recipient. A 52-year-old male patient with renal allograft developed cryptogenic end-stage liver failure and was accepted as a candidate for liver transplant. Before transplant, he was admitted with severe abdominal pain, which turned out to result from ileal perforation. Pathologic evaluation of the intestinal resection showed diffuse malignant lymphoid infiltration of the ileum, consistent with anaplastic large-cell lymphoma. The tumor was positive for Epstein-Barr virus genome. Anaplastic large-cell lymphoma is a rare form of T-cell posttransplant lymphoproliferative disorder that is infrequently associated with Epstein-Barr virus. The occurrence of this extraordinary form of post transplant lymphoproliferative disorder, its late onset, intestinal localization, and Epstein-Barr virus as sociation represent a unique clinical rarity.

De Novo Malignant Neoplasms in Renal Transplant Patients.

OBJECTIVES: The aim of this study was to evaluate the incidence of posttransplant malignancy in kidney transplant patients and investigate the clinical and histopathologic features of these patients. MATERIALS AND METHODS: We retrospectively reviewed information on donor and recipient characteristics, patient and graft survival, and cancer incidence after transplant for 867 kidney transplant patients. Patients with neoplasms prior to transplant were excluded. A follow-up study estimated cancer incidence after transplant. RESULTS: Neoplasms were diagnosed in 59 patients (6.8%), 41 men and 18 women; 22 (37.3%) had skin tumors, 19 (32.2%) had solid tumors, 10 (16.9%) had posttransplant lymphoproliferative disorders, and 8 (13.6%) had Kaposi sarcoma. The mean age at the time of malignant tumor diagnosis was 42.7 ± 13.6 years, and statistically significant differences were found between tumor groups (P < .01). The average latency period between transplant and diagnosis of malignant tumors was 99.8 ± 56.9 months for solid tumors, 78.4 ± 52 months for skin tumors, 64.5 ± 48.8 months for posttransplant lymphoproliferative disorders, and 13.5 ± 8.8 months for Kaposi sarcoma, with significant difference found between tumor groups (P < .01). Ten patients (16.9%) had more than 1 malignant tumor. Eighteen patients died, with a mean time to death of 31.5 ± 22.8 months after tumor diagnosis. A significant positive association was found between survival and the number of tumors (P = .001); 5-year survival after tumor diagnosis was 81% and 40% for patients with 1 malignant tumor and patients with more than 1 malignant tumor, respectively. CONCLUSIONS: Malignancy is a common cause of death after renal transplant. Early detection and treatment of posttransplant malignancies is an important challenge. Screening these patients for malignancies posttransplant is crucial, and efforts should be directed to define effective immunosuppressive protocols that are associated with a lower incidence of malignancy.

Histologic Changes in Bone Marrow Biopsies From Liver Transplant Patients.

OBJECTIVES: Liver transplant may complicated by various hematologic conditions, resulting in indication for bone marrow biopsy. Immunosuppressive therapies, specific infections, and secondary neoplasms affect bone marrow. In the present study, we evaluated the histologic spectrum of bone marrow findings in liver allograft recipients. MATERIALS AND METHODS: Of 338 patients who received liver transplants and were followed at the Baskent University, Faculty of Medicine, 44 patients underwent bone marrow biopsy. The medical and pathologic information about these patients were evaluated, including age at liver transplant, age at bone marrow biopsy, sex, primary disease, bone marrow histology, and indication for bone marrow biopsy. RESULTS: Of 44 patients who required bone marrow sampling, 30 were male (68.2%), and 14 were female (31.8%). Fifteen patients (34.1%) were in pediatric age group at the time of transplant. The most common cause of liver insufficiency leading to liver transplant was viral hepatitis in 11 patients (25%), followed by cryptogenic cirrhosis in 10 patients (22.8%). The source of the graft liver was a living donor in 40 patients (90.9%). The average age at transplant was 28.8 years, and the mean age at bone marrow sampling was 29.9 years. Nineteen patients (43.2%) required bone marrow sampling within the first year after transplant. The most common histologic findings were hypocellular, and normocellular bone marrow, observed in 18 patients (40.9%) each. Six patients (13.6%) had bone marrow biopsies for staging of posttransplant lymphoproliferative disorder. Only 1 patient of the 6 with this disease (16.7%) had malignant infiltration of the bone marrow, which was a case of Burkitt lymphoma developed as posttransplant lymphoproliferative disorder, and this was the only malignant infiltration in this patient group (2.3%). Neither specific infections nor granulomatous inflammation was detected. CONCLUSIONS: Bone marrow morphology has a major role in the follow-up of liver transplant patients, who may present with peripheral blood cytopenias. The present study represents the first systematic evaluation of bone marrow findings in liver allograft recipients.

Splenic Peliosis Resulting in Spontaneous Splenic Rupture in a Concomitant Hepatic and Renal Allograft Recipient.

Splenic peliosis is an exceedingly rare complication following liver and kidney transplant, with few previously reported cases. A 24-year-old man with chronic renal and hepatic failure due to primary oxalosis underwent concomitant renal and hepatic transplant. On the eighth day of successful transplant, he showed signs and symptoms of hypovolemia with suspicion of intra-abdominal bleeding. Diagnostic laparotomy was performed, yielding splenic rupture, and a splenectomy was performed. Macroscopically, the spleen was ruptured, and the cut surface displayed multiple parenchymal blood-filled cysts. Microscopically, the splenic microarchitecture was distorted by numerous irregular hemorrhagic lacunes partially lined by sinusoidal endothelium. Splenic peliosis was diagnosed. The patient recovered with splenectomy. Peliosis is a condition characterized by multiple bloodfilled cavities in parenchymatous organs, and it most frequently affects the liver. It is thought to be related to many conditions, including hematologic malignancies, acquired immuno deficiency syndrome, chronic alcoholism, use of oral contraceptives, and posttransplant immunodeficiency state. However, peliosis of the spleen, compared with the liver, is relatively rare, and it may cause spontaneous splenic rupture. Although rare, splenic peliosis and secondary splenic rupture is a significant posttransplant complications leading to unexplained hypovolemia.

A Unique Case of Intranasal Metastasis from Occult Poorly Differentiated Thyroid Carcinoma.

BACKGROUND: Poorly differentiated thyroid carcinomas (PDTCs) lie, both morphologically and behaviorally, between well-differentiated and undifferentiated carcinomas. Metastasis of poorly differentiated thyroid carcinoma to the intranasal cavity has not been reported previously in the literature. CASE REPORT: A 48-year-old male patient presented with massive epistaxis and nasal obstruction. On nasal examination, a bleeding, vascular mass was seen filling the left nasal cavity. The histopathological report of the nasal mass was well-differentiated thyroid carcinoma metastasis. Whole body scintigraphy, ultrasonography and positron emission tomography were done to rule out other possible metastases in the body and determine the origin of the tumor, which was identified as the left lobe of the thyroid gland, and there were multiple metastases involving the lung, sacroiliac area, and left humerus. Histopathological examination of a thyroidectomy specimen revealed PDTC consisting of insular, follicular, and papillary components. Postoperatively, the patient received radioactive iodine ablation therapy (iodine-131) and a course of external beam radiation therapy to the sacroiliac area and other metastatic regions. No recurrences were observed in a follow-up period of 5 years after surgery. CONCLUSION: The metastasis of differentiated thyroid carcinoma as a component of PDTC to the intranasal cavity has not been reported before. It is interesting that the well-differentiated component of the tumor was metastasized in our patient. Due to the aggressiveness of PDTC and the poor survival rates in patients who undergo surgery alone, a multidisciplinary treatment approach is required.

Bone marrow biopsy in patients with renal transplant: spectrum of findings and diagnostic use.

OBJECTIVES: Renal transplant may be complicated by cytopenia, fever of unknown etiology, or hematolymphoid malignancies. Bone marrow biopsy may be indicated to evaluate these complications. However, to the best of our knowledge, no previous study has systematically documented the characteristics of bone marrow biopsy in these patients. The present study reports the range of bone marrow findings in renal transplant recipients. MATERIALS AND METHODS: We selected 85 patients who underwent bone marrow biopsy among 1745 renal transplant recipients who had transplant at Ba skent University from January 1990 to December 2013. The files of these patients were reviewed for age, sex, age at renal transplant, underlying renal disease, donor type, immunosuppressive therapy, presence or absence of acute humoral or cellular rejection, duration between transplant and bone marrow biopsy, indication for bone marrow biopsy, and histopathologic diagnoses of bone marrow biopsies. RESULTS: The most common cause of renal insufficiency leading to transplant in this patient group was unknown etiology, observed in 24 patients (28.2%). The most common indication for bone marrow biopsy was blood cytopenia, detected in 56 patients (65.9%). Neoplastic involvement of the bone marrow was detected in 6 patients (7.1%), all of which were hematolymphoid malignancies. Corticosteroids were the most commonly used immunosuppressive agents, administered to all patients. CONCLUSIONS: Bone marrow biopsy provides important information in renal transplant recipients, especially in cases of neoplastic bone marrow involvement, specific inflammation, and amyloidosis, which are uncommon in this patient group. The overall diagnostic use is related to the individual situation of each patient.

Pathological evaluation of the filum terminale tissue after surgical excision.

PURPOSE: Tethered cord syndrome (TCS) is an important disease and can produce progressive neurological symptoms. Studies about the filum terminale (FT) have drawn attention to the importance of histopathological investigation of this structure. The most interesting of these subtypes is the FT that incorporates peripheral nerve fibers (PNF). Our study aimed to analyze the frequency of PNF in the FT of 40 cases diagnosed with TCS. METHODS: We performed a retrospective histopathological investigation of FT excised during surgery of patients with TCS who underwent de-tethering. Neurologic and other types of postoperative complications were also revised. RESULTS: Analysis of the samples showed six dominant histopathological subtypes in the FT: fibroadipose tissues including peripheral nerve bundles (n = 14, 37 %), fibroadipose tissue (n = 10, 25 %), fibrous or adipose tissue (n = 7, 17 %), glial tissues including peripheral nerve sections (n = 4, 10 %), and ependymal and glial tissues (n = 4, 10 %). None of the patients presented with neurologic postoperative complications. CONCLUSION: Embryologic studies revealed that it is common to encounter different histological subtypes of FT pathology. However, the presence of peripheral nerve cells in the FT is important for neurosurgical practice due to the risk of sectioning a functional structure during surgery. In our analysis, we demonstrated the high frequency of PNF in FT pathology. However, since none of the patients showed any symptoms of neurologic deterioration, we considered that these fibers were probably not functional. Our findings emphasize the importance of neuromonitoring in TCS surgery. Although we consider that most of the fibers are probably not functional, neuromonitoring after surgery may prevent serious complications.

Report of an unusual case: testicular involvement of chronic myeloid leukemia 10 years after the complete response.

Testicular extra-medullary myeloid cell tumours are rare tumours presenting in most cases with painless testicular swelling. We are representing here along of a case of 21-year-old man with painless scrotal swelling. From his medical history, he was treated by allogenic bone-marrow transplantation and chemotherapy 10 years ago because of chronic myeloid leukemia. The pathology of orchiectomy specimen revealed malign cells with blastic cell infiltration means a late relapse of chronic myeloid leukemia. The patient has been in hematological remission and no evidence of any myeloid disorders by 10 years' follow up. Although testicular involvement is a rare and an unusual event in blast crisis of chronic myeloid leukemia, extramedullary myeloid cell tumour should be considered in the diagnosis of intratesticular tumours.

Hyperbaric oxygen in epidural fibrosis: is there a potential for treatment?

AIM: To investigate the effects of hyperbaric oxygen treatment on epidural fibrosis formation in an experimental laminectomy model. MATERIAL AND METHODS: Twenty-four Wistar rats underwent L5-L6 total laminectomy and divided into three groups. Animals in the control group received no further treatment while animals in short and long term groups received 2,5 ATM ABS of hyperbaric oxygen for 3 and 7 days, respectively. The amount of epidural fibrosis was analyzed histologically at the end of 42 days of follow up. RESULTS: The ratio of severe fibrosis was 57% in the control, 29% in the short HBOT, and 14% in the long HBOT groups. Although there was a clear trend towards having less fibrosis in the HBOT groups, the difference did not reach to the level of statistical significance (p=0.242), probably due to small number of animals used in this preliminary study. CONCLUSION: Our findings suggest that hyperbaric oxygen treatment may have favorable effects on epidural fibrosis. Further studies with larger cohorts are required to prove our results.