Histopathological Analysis of Ligamentum Flavum in Lumbar Spinal Stenosis and Disc Herniation

Idiris Altun,Kasım Zafer Yüksel 대한척추외과학회 2017 Asian Spine Journal Vol.11 No.1

Study Design: Histopathological analyses were performed in ligamentum flavum (LF) hypertrophy patients with lumbar spinal stenosis (LSS) and lumbar disc herniation (LDH). Purpose: The aim of the present study was to evaluate histopathological changes in LF patients with LSS and LDH. Overview of Literature: LSS is the most common spinal disorder in elderly patients. This condition causes lower back and leg pain and paresis, and occurs as a result of degenerative changes in the lumbar spine, including bulging of the intervertebral discs, bony proliferation of the facet joints, and LF thickening; among these, LF thickening is considered a major contributor to the development of LSS. Methods: A total of 71 patients operated with the surgical indications of LSS and LDH were included. LF samples were obtained from 31 patients who underwent decompressive laminectomy for symptomatic degenerative LSS (stenotic group) and from 40 patients who underwent lumbar discectomy for LDH (discectomy group). LF materials were examined histopathologically, and other specimens were examined for collagen content, elastic fiber number and array, and presence of calcification. Results: The stenotic and discectomy groups did not differ with regard to mean collagen concentration or mean elastic fiber number (p =0.430 and p =0.457, respectively). Mean elastic fiber alignment was 2.36±0.99 in the stenotic group and 1.38±0.54 in the discectomy group (p <0.001). Mean calcification was 0.39±0.50 in the stenotic group, whereas calcification was not detected (0.00±0.00) in the discectomy group; a statistically significant difference was detected (p <0.001) between groups. Conclusions: LF hypertrophy in spinal stenosis may occur as a result of elastic fiber misalignment along with the development of calcification over time. Further studies determining the pathogenesis of LSS are needed.

Ankylosing Spondylitis: Patterns of Spinal Injury and Treatment Outcomes

Idiris Altun,Kasım Zafer Yuksel 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.4

Study Design: Retrospective review. Purpose: We retrospectively reviewed our patients with ankylosing spondylitis (AS) to identify their patterns of spinal fractures to help clarify management strategies and the morbidity and mortality rates associated with this group of patients. Overview of Literature: Because of the brittleness of bone and long autofused spinal segments in AS, spinal fractures are common even after minor trauma and often associated with overt instability. Methods: Between January 1, 1998 and March 2011, 30 patients (23 males, 7 females; mean age, 70.43 years; range, 45 to 95 years) with the radiographic diagnosis of AS of the spinal column had 42 fractures. Eight patients presented with significant trauma, 17 after falls, and 5 after minor falls or no recorded trauma. Eleven patients presented with a neurological injury, ranging from mild sensory loss to quadriplegia. Results: There were 16 compression and 10 transverse fractures, two Jefferson’s fractures, one type II and two type III odontoid process fractures, and five fractures of the posterior spinal elements (including lamina and/or facet, three spinous process fractures, three transverse process fractures). Twenty-four fractures affected the craniocervical junction and/or cervical vertebrae, 17 were thoracic, and one involved the lumbar spine. The most affected vertebrae were C6 and T10. The mean follow-up was 29.9 months. One patient was lost to follow-up. Eighteen patients were treated conservatively with bed rest and bracing. Twelve patients underwent surgery for spinal stabilization either with an anterior, posterior or combined approach. Conclusions: Nonsurgical treatment can be considered especially in the elderly patients with AS and spinal trauma but without instability or major neurological deficits. The nonfusion rate in conservatively treated patients is low. When treatment is selected for patients with spinal fractures and AS, the pattern of injury must be considered and the need for individualized treatment is paramount.

Experimental & computational study on fly ash and kaolin based synthetic lightweight aggregate

Süleyman İpek,Kasım Mermerdaş 사단법인 한국계산역학회 2020 Computers and Concrete, An International Journal Vol.26 No.4

The objective of this study is to manufacture environmentally-friendly synthetic lightweight aggregates that may be used in the structural lightweight concrete production. The cold-bonding pelletization process has been used in the agglomeration of the pozzolanic materials to achieve these synthetic lightweight aggregates. In this context, it was aimed to recycle the waste fly ash by employing it in the manufacturing process as the major cementitious component. According to the well-known facts reported in the literature, it is stated that the main disadvantage of the synthetic lightweight aggregate produced by applying the cold-bonding pelletization technique to the pozzolanic materials is that it has a lower strength in comparison with the natural aggregate. Therefore, in this study, the metakaolin made of high purity kaolin and calcined kaolin obtained from impure kaolin have been employed at particular contents in the synthetic lightweight aggregate manufacturing as a cementitious material to enhance the particle crushing strength. Additionally, to propose a curing condition for practical attempts, different curing conditions were designated and their influences on the characteristics of the synthetic lightweight aggregates were investigated. Three substantial features of the aggregates, specific gravity, water absorption capacity, and particle crushing strength, were measured at the end of 28-day adopted curing conditions. Observed that the incorporation of thermally treated kaolin significantly influenced the crushing strength and water absorption of the aggregates. The statistical evaluation indicated that the investigated properties of the synthetic lightweight aggregate were affected by the thermally treated kaolin content more than the kaoline type and curing regime. Utilizing the thermally treated kaolin in the synthetic aggregate manufacturing lead to a more than 40% increase in the crushing strength of the pellets in all curing regimes. Moreover, two numerical formulations having high estimation capacity have been developed to predict the crushing strength of such types of aggregates by using softcomputing techniques: gene expression programming and artificial neural networks. The R-squared values, indicating the estimation performance of the models, of approximately 0.97 and 0.98 were achieved for the numerical formulations generated by using gene expression programming and artificial neural networks techniques, respectively.

Lumbar herniated disc: spontaneous regression

( Idiris Altun ),( Kasım Zafer Yuksel ) 대한통증학회 2017 The Korean Journal of Pain Vol.30 No.1

Background: Low back pain is a frequent condition that results in substantial disability and causes admission of patients to neurosurgery clinics. To evaluate and present the therapeutic outcomes in lumbar disc hernia (LDH) patients treated by means of a conservative approach, consisting of bed rest and medical therapy. Methods: This retrospective cohort was carried out in the neurosurgery departments of hospitals in Kahramanmaras city and 23 patients diagnosed with LDH at the levels of L3-L4, L4-L5 or L5-S1 were enrolled. Results: The average age was 38.4 ± 8.0 and the chief complaint was low back pain and sciatica radiating to one or both lower extremities. Conservative treatment was administered. Neurological examination findings, durations of treatment and intervals until symptomatic recovery were recorded. Lasegue tests and neurosensory examination revealed that mild neurological deficits existed in 16 of our patients. Previously, 5 patients had received physiotherapy and 7 patients had been on medical treatment. The number of patients with LDH at the level of L3-L4, L4-L5, and L5-S1 were 1, 13, and 9, respectively. All patients reported that they had benefit from medical treatment and bed rest, and radiologic improvement was observed simultaneously on MRI scans. The average duration until symptomatic recovery and/or regression of LDH symptoms was 13.6 ± 5.4 months (range: 5-22). Conclusions: It should be kept in mind that lumbar disc hernias could regress with medical treatment and rest without surgery, and there should be an awareness that these patients could recover radiologically. This condition must be taken into account during decision making for surgical intervention in LDH patients devoid of indications for emergent surgery. (Korean J Pain 2017; 30: 44-50)

Acute Myocardial Infarction in a Young Man; Fatal Blow of the Marijuana: A Case Report

Mustafa Yurtdas¸,Mehmet Kasım Aydın 대한심장학회 2012 Korean Circulation Journal Vol.42 No.9

Marijuana is known to have been used for medicinal and recreational purposes for thousands of years. Although marijuana has some di-verse effects on cardiovascular system, there is insufficient knowledge concerning acute myocardial infarction (AMI) associated with mari-juana and its underlying mechanism. We report the case of a 26 year-old young man suffering from ST-elevated AMI caused by marijuana abuse, which was successfully treating with percutaneous coronary intervention. It should be kept in mind that marijuana could be one of the most probable causes of AMI observed in apparently healthy young persons who use this drug.

Ultimate Capacity Prediction of Axially Loaded CFST Short Columns

Esra Mete Güneyisi,Ayşegül Gültekin,Kasım Mermerdaş 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.1

Composite columns have superior strength and ductility performance, and they have become more widely accepted in the engineering applications. However, the filled tubular columns require more attention. This study aims to present a new formulation for the axial load carrying capacity ( Nu ) of circular concrete filled steel tubular (CFST) short columns having various geometrical and material properties. Although there have been some empirical relations for predicting Nu in the literature, genetic algorithm based explicit formulation is not available. In the current study, 314 comprehensive experimental data samples presented in the previous studies were examined to prepare a data set for training and testing of the prediction model. The prediction parameters were selected as outer diameter of column (D), wall thickness ( t ), length of column ( L ), compressive strength of concrete ( fc ), and yield strength of steel ( fy ). The prediction model was obtained by means of gene expression programming (GEP). The proposed model was compared with available ones presented in the current design codes (ACI, Australian Standards, AISC, AIJ, Eurocode 4, DL/T, and CISC) and some existing empirical models proposed by researchers. The prediction performance of all models were also evaluated by the statistical parameters. The results indicated that the GEP model was much better than the available formulae, yielding higher correlation coefficient and lower error

Prediction of the flexural overstrength factor for steel beams using artificial neural network

Esra Mete Güneyisi,Mario D’Aniello,Raffaele Landolfo,Kasım Mermerdaş 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.17 No.3

The flexural behaviour of steel beams significantly affects the structural performance of the steel frame structures. In particular, the flexural overstrength (namely the ratio between the maximum bending moment and the plastic bending strength) that steel beams may experience is the key parameter affecting the seismic design of non-dissipative members in moment resisting frames. The aim of this study is to present a new formulation of flexural overstrength factor for steel beams by means of artificial neural network (NN). To achieve this purpose, a total of 141 experimental data samples from available literature have been collected in order to cover different cross-sectional typologies, namely I-H sections, rectangular and square hollow sections (RHS-SHS). Thus, two different data sets for I-H and RHS-SHS steel beams were formed. Nine critical prediction parameters were selected for the former while eight parameters were considered for the latter. These input variables used for the development of the prediction models are representative of the geometric properties of the sections, the mechanical properties of the material and the shear length of the steel beams. The prediction performance of the proposed NN model was also compared with the results obtained using an existing formulation derived from the gene expression modeling. The analysis of the results indicated that the proposed formulation provided a more reliable and accurate prediction capability of beam overstrength.

Advantages of Simultaneous Cementless Bilateral Unicondylar Knee Arthroplasty Compared to Staged Surgery

Ali Şahin,Şahin Çepni,Enejd Veizi,Yasin Erdoğan,Ahmet Fırat,Kasım Kılıçarslan 대한정형외과학회 2023 Clinics in Orthopedic Surgery Vol.15 No.5

Background: Unicondylar knee arthroplasty (UKA) is an effective procedure, which reduces pain, increases range of motion, and improves function. UKA could be performed simultaneously or in staged sessions. This study aimed to compare bilateral cementless UKA performed simultaneously and in staged sessions in terms of complications, hemoglobin levels, transfusions, and functional outcomes. Methods: Patients undergoing bilateral UKA for symptomatic medial compartment osteoarthritis were retrospectively analyzed. Of the 73 patients who met the inclusion criteria, 40 underwent surgery simultaneously and 33 underwent surgery in separate sessions. Operative time, length of hospital stay, change in hemoglobin, need for blood transfusion, complications, and functional outcomes were assessed. Results: There was no statistically significant difference between the two groups in demographic data. Simultaneously operated patients had a significantly shorter hospital stay and shorter operative time. Statistically significant improvements in clinical scores were noted in both groups. The degree of improvement in functional scores did not differ between the groups. There was no difference between the two groups in terms of complication rates, but the number of periprosthetic tibial fractures was higher in the simultaneous group. Conclusions: Simultaneous bilateral cementless UKA was more advantageous in terms of cumulative hospital stay and total operation time with similar clinical results when compared to a staged procedure. While the overall complication rate was similar, the rate of periprosthetic fractures was 5% in the simultaneous group.