Browsing by Author "Derincek, Alihan"

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Effect of PLIF and TLIF on sagittal spinopelvic balance of patients with degenerative spondylolisthesis
(2018) Ozalay, Metin; Uysal, Mustafa; Derincek, Alihan; Kochai, Alauddin; Turker, Mehmet; 29705297
Objective: The aim of this study was to evaluate the effects of PLIF and TLIF on sagittal spinopelvic balance and to compare radiological results of two surgical procedures with regard to spinopelvic parameters. Methods: Thirty-five patients (34 female and 1 male; mean age: 52.29 +/- 13.08 (range: 35-75)) with degenerative spondylolisthesis cases were included in the study. Patients were divided into two groups according to surgical technique: PLIF and TLIF. The level and the severity of listhesis according to Meyerding classification were assessed and spinopelvic parameters including sacral slope, pelvic tilt, pelvic incidence (PI), lumbar lordosis, and segmental lumbar lordosis were measured on digital X-rays. All preoperative and postoperative parameters and the results were compared between two groups. Results: The age distribution was similar in both groups (p = 0.825) and there was no difference between the mean PI of the groups (p = 0.616). In 15 patients, spondylolisthesis level were at the L5-S1 level (PLIF: 8, TLIF: 7), in 16 patients at the L4-L5 level (PLIF: 6, TLIF: 10) and in 4 patients at the L3-L4 level (PLIF: 2, TLIF: 2). According to Meyerding classification, before the operation, the sliding grades were 0 in 4 patients, 1 in 21 patients, 2 in 7 patients, and 3 in 3 patients. The grades changed into 0 in 28 patients, 1 in 5 patients, and 2 in 2 patients after surgery. There were no differences in the grade of listhesis between PLIF and TLIF groups preoperatively (p = 0.190) and postoperatively (p = 0.208). In both groups, the spondylolisthesis-related deformities of patients were significantly corrected after surgery (p < 0.001). Conclusion: PLIF and TLIF techniques have similar radiological results in restoring the sagittal spinopelvic balance in patients with degenerative spondylolisthesis. Both techniques are good options to achieve reduction and fusion in patients with degenerative spondylolisthesis, but have no advantage over each other for restoring spinopelvic balance. (C) 2018 Turkish Association of Orthopaedics and Traumatology. Publishing services by Elsevier B.V.
Restoration of pull-out strength of the failed pedicle screw: biomechanical comparison of calcium sulfate vs polymethylmethacrylate augmentation
(2014) Guler, Umit Ozgur; Derincek, Alihan; Hersekli, Murat Ali; Ozalay, Metin; Cinar, Bekir Murat; Acaroglu, Emre
Objective: The aim of the present study was to compare calcium sulfate (CAS) and polymethylinethaaylate (PMMA) bone cements used for the augmentation of a failed pedicle screw with biomechanical pull-out strength (POS) testing. Methods: Thirty lumbar vertebrae were harvested from 6 calves and bone mineral densities (BMD) were measured. Primary polyaxial pedicle screws were randomly inserted and pulled out and the POSs of the specimen were recorded. For revision, specimens were randomly assigned to the CAS-augmented pedide screws group (Group 1) or PMMA-augmented pedicle screw group (Group 2). Pull-out tests were repeated to compare both groups. Results: Mean BMD of the specimens was 1.006 +/- 0.116 g/cm(2). There were no statistically significant differences between BMD results of the two groups (p=0.116). For Group 1, mean POS of primary screws was 2,441.3 +/- 936.4 N and was 2,499.5 +/- 1,425.1 N after CAS augmentation, demonstrating no statistically significant difference (p=0.865). In Group 2, mean POS of the primary screws was 2,876.6 +/- 926.6 N and significantly increased to 3,745.5 +/- 1,299.2 N after PMMA augmentation (p=0.047). There was also a significant difference in mean POS between the CAS and PMMA groups (p=0.026). Conclusion: Although CAS augmentation facilitates a revision screw POS as strong as that of primary screws, it is not as strong as PMMA augmentation.
Spinal Metastatic Disease Survival Analysis of 146 Patients and Evaluation of 4 Different Preoperative Scoring Systems
(2020) Derincek, Alihan; Guler, Umit O.; Uysal, Mustafa; Ozalay, Metin; 0000-0002-5375-635X; 31393277; AAJ-4844-2021; O-7590-2017
Study Design: This was a retrospective analysis. Objective: The objective of this study was to evaluate the predictive value of the 4 different scoring systems Tomita, Bauer modified, Tokuhashi revised, and Van der Linden and some parameters that are used in these scoring systems. Summary and Background Data: Prediction of the survival period before treatment for spinal metastasis is extremely important. A lot of scoring systems have been described to predict the survival periods and to select the ideal treatment modality in the literature. Materials and Methods: Retrospectively 146 patients with spinal metastasis were investigated between 2002 and 2011. The following parameters were analyzed: age, pathologic vertebra fracture, neurological deficit, visceral metastasis, diagnosis of primary tumor and its spinal metastasis interval, other skeletal metastasis, involved region of vertebra, and undergone spinal surgery. Patients were also scored by the 4 different scoring systems. The survival period was calculated from date of diagnosis of the spinal metastasis to the date of death or last follow-up (minimum: 12 mo). Cox regression, Kaplan-Meier survival test, and Cronbach alpha tests were performed for statistical analysis. Results: Median overall survival for all patients was 13 months (range: 1-68 mo). The primary tumor (P=0.015), existence of visceral metastasis (P=0.017), presence of pathologic vertebra fracture (P=0.009), and undergone spinal surgery (P=0.047) showed significant influence on survival. Each scoring system was reliable and concordant with the other scoring systems (Cronbach alpha=80%); however, after 2 years, Modified Bauer score appeared to be the most reliable system for predicting survival (Cronbach alpha=25%). Conclusions: According to this analysis, lung cancer, visceral metastasis, pathologic vertebra fracture, and undergone spinal surgery have shown a negative effect on survival. All 4 scoring systems were reliable for predicting survival of patients with spinal metastatic disease. However, modified Bauer scoring system seems to be more predictive after 2 years.