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Dive into the research topics where Mehmet Resid Onen is active.

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Featured researches published by Mehmet Resid Onen.


World Neurosurgery | 2016

Rational Roots of Sympathetic Overactivity by Neurogenic Pulmonary Edema Modeling Arising from Sympathyco-Vagal Imbalance in Subarachnoid Hemorrhage: An Experimental Study.

Mehmet Resid Onen; Ilhan Yilmaz; Leyla Ramazanoglu; Osman Tanriverdi; Mehmet Dumlu Aydin; Ayhan Kanat; Coskun Yolas; Sare Sipal

BACKGROUND Autonomous innervations of the lungs are maintained by cervical sympathetic and vagal nerves. Sympathetic overactivity-induced neurogenic pulmonary edema (NPE) is known as a serious complication of subarachnoid hemorrhage, but the rational neuronal mechanism of that overactivity has not yet been clarified fully. The aim of this study was to examine whether there is a relationship between vagal nerve ischemia related sympathetic overactivity and neurogenic pulmonary edema in subarachnoid hemorrhage. METHODS This study was conducted on 27 rabbits. A control group was formed of 5 animals, a sham group of 7 to which saline was administered, and a study group of 15 animals that were injected with homologous arterial blood into the cisterna magna. Electrocardiography and respiratory rhythm parameters were monitored for 3 weeks and the animals were then decapitated. Statistical analysis was made of the numbers of degenerated axons in the pulmonary branches of the vagal nerves, the neuron density of stellate ganglions and the vasospasm index of the pulmonary arteries. RESULTS In the control group, the normal respiration rate was 34 ± 6 bpm, total axon number was 1600 ± 270/mm(2), degenerated axon number was 10 ± 3/mm(2), and vasospasm index was 1.34 ± 0.25. The sham group values were 30 ± 3 bpm, 163 ± 47/mm(2), and 1.95 ± 0.45 and the study group values were 45 ± 8 bpm, 530 ± 92/mm(2), and 2.76 ± 0.83. The mean stellate ganglion neuron density was evaluated as 8.112 ± 1.230/mm(3) in all animals, as 7.420 ± 4.10/mm(3) in animals with slight NPE, and as 12.512 ± 1.236/mm(3) in animals that developed severe NPE. CONCLUSION High neuron density of stellate ganglion may have important roots in sympathetic overactivity-related NPE development in subarachnoid hemorrhage.


World Neurosurgery | 2015

The Reliability of the Ultrasonic Bone Scalpel in Cervical Spondylotic Myelopathy: A Comparative Study of 46 Patients

Mehmet Resid Onen; Evren Yuvruk; Sinem Akay; Sait Naderi

BACKGROUND In patients with cervical spondylotic myelopathy (CSM), laminectomy is usually performed with a Kerrison rongeur or a high speed drill (HSD).The HSD, which is most often selected for laminectomy, may cause complications such as duratomy, thermal and mechanical neural injuries. With an ultrasonic bone scalpel (UBS), a less traumatic laminectomy can be performed in a shorter time. The aim of this study was to compare the results of laminectomies using HSD and UBS. METHODS Evaluation was made in 46 patients who were operated on for CSM. Cervical laminectomy was performed on 23 patients using the UBS (group I) and to 23 using the HSD (group II). A comparison was made of the 2 groups in respect of demographic characteristics, laminectomy levels, mean laminectomy duration, bleeding rates, and surgical complications. RESULTS In group I, the mean laminectomy time was 2.2 ± 0.4 min/level, mean blood loss was 180 mL, hospitalization was 3.0 ± 0.0 days, and C5 radiculopathy was seen in 1 patient. In group II, the mean laminectomy time was 7.4 ± 2.6 min/level, mean blood loss was 380 mL, hospitalization was 3.7 ± 1.3 days, C5 radiculopathy was seen in 1 patient and dura injuries in 3 patients. The recovery rate was determined as 47.6% in group I and 48.8% in group II. CONCLUSIONS For patients with CSM, laminectomy using the UBS provides a safe, rapid, and effective decompression with a lesser blood loss. The low rate of complications lessens the postoperative morbidity rates and shortens hospital stay.


Spine | 2015

Efficiency of Hyperbaric Oxygen Therapy in Iatrogenic Spinal Infections.

Mehmet Resid Onen; Evren Yuvruk; Gül Karagöz; Sait Naderi

Study Design. Retrospective clinical study. Objective. The aim of this study is to reveal the effectiveness of HBO therapy in iatrogenic spinal infections intractable to antibiotic therapy alone. Summary of Background Data. The efficiency of hyperbaric oxygen (HBO) therapy, which is currently being used in many areas, has been proven in infections in deep and superficial locations and in osteomyelitis. The aim of this study is to reveal effectives of HBO therapy in iatrogenic spinal infections intractable to antibiotic alone therapy. Methods. HBO therapy was given to 19 cases of iatrogenic spinal infection between 2008 and 2013. Adjuvant HBO therapy was applied to cases that had exhibited no improvement in clinical and laboratory findings despite medical treatment for at least 3 weeks. Several parameters including demographic characteristics, surgical area, etiology and the surgical treatment modality, microbiology (culture material and causative organism), clinical and laboratory results, duration of HBO therapy, and outcome were reviewed. Results. The mean age was 54.6 years (range: 32–75 years). Iatrogenic spinal infections were most frequent in the lumbar region. It occurred after spine instrumentation in 12 cases and after micro‐discectomy in 7 cases. The average number of HBO therapy sessions applied was 20.1 (range: 10–40). Wound discharge and clinical and laboratory findings recovered in all cases at the end of the therapy course. No revision or removal of the instrumentation was necessary in the instrumented cases. Conclusion. HBO therapy is a treatment modality, which is safe and efficient as an adjuvant therapy in the treatment of infections. It was also seen to be effective in the prevention of revision procedures and instrumentation failures in iatrogenic osteomyelitis cases, which had occurred following spinal instrumentation. Level of Evidence: 4


Turkish Neurosurgery | 2016

Uncovering of The Forgotten Effect of Superior Cervical Ganglia On Pupil Diameter Determination in Subarachnoid Hemorrhage: Experimental Study.

Mehmet Resid Onen; Ilhan Yilmaz; Ramazanoglu L; Aydin; Keles S; Baykal O; Nazan Aydin; Cemal Gundogdu

AIM To investigate the relationship between neuron density of the superior cervical sympathetic ganglia and pupil diameter in subarachnoid hemorrhage. MATERIAL AND METHODS This study was conducted on 22 rabbits; 5 for the baseline control group, 5 for the SHAM group and 12 for the study group. Pupil diameters were measured via sunlight and ocular tomography on day 1 as the control values. Pupil diameters were re-measured after injecting 0.5 cc saline to the SHAM group, and autologous arterial blood into the cisterna magna of the study group. After 3 weeks, the brain, superior cervical sympathetic ganglia and ciliary ganglia were extracted with peripheral tissues bilaterally and examined histopathologically. Pupil diameters were compared with neuron densities of the sympathetic ganglia and ciliary ganglia which were examined using stereological methods. RESULTS Baseline values were; normal pupil diameter 7.180±620 ?m and mean neuron density of the superior cervical sympathetic ganglia 6.321±510/mm3, degenerated neuron density of ciliary ganglia was 5±2/mm3 after histopathological examination in the control group. These values were measured as 6.850±578 ?m, 5.950±340/mm3 and 123±39/mm3 in the SHAM group and 9.910±840 ?m, 7.950±764/mm3 and 650±98/mm3 in the study group. A linear relationship was determined between neuron density of the superior cervical sympathetic ganglia and pupil diameters (p < 0.005). Degenerated ciliary ganglia neuron density had an inverse effect on pupil diameters in all groups (p < 0.0001). CONCLUSION Highly degenerated neuron density of the ciliary ganglion is not responsible for pupil dilatation owing to parasympathetic pupilloconstrictor palsy, but high neuron density of the pupillodilatatory superior cervical sympathetic ganglia should be considered an important factor for pupil dilatation.


Journal of Spine | 2015

Recurrent Lumbar Disc Herniation in Pregnant Patient: A Case Report

Mehmet Resid Onen; Evren Yuvruk; Mehmet Erdem Akcay; Sait Naderi

Introduction: Lower back and leg pain are frequently seen pathologies in pregnancy. However, a small proportion of these complaints develop in association with lumbar disc hernias. Due to maternal and fetal factors, diagnosis and treatment during pregnancy has to be different than for non-pregnant patients. Methods: A 36 year old, 28-week pregnant patient presented with ever-increasing pain in the right leg, lower back, and reduced power in the extensor hallucis longus. The patient had undergone surgery at another clinic about 2.5 years ago because of right L4-5 disc herniation. Therefore the patient was evaluated by lumbar magnetic resonance images [MRI]. The MRI determined the right L4-5 recurrent disc herniation. Results: The patient underwent successful surgery in the lateral decubitus position under general anesthesia. No complications developed in mother or fetus. Conclusion: Recurrent lumbar disc herniation during pregnancy has not been reported. A lumbar micro-discectomy procedure for a pregnant patient resulted in a successful clinical outcome.


World Neurosurgery | 2018

Radiological Anatomy of the Lumbar Interlaminar Window and Surgical Considerations for Lumbar Interlaminar Endoscopica and Microsurgical Disc Surgery

Zakir Sakçı; Elif Fidan; Yunus Yaşar; Mehmet Resid Onen; Hikmet Uluğ; Sait Naderi

OBJECTIVE The interlaminar window is the most important corridor during both interlaminar approaches to intervertebral discs. The aim of this study was to measure radiologic parameters related to endoscopic and microsurgical interlaminar discectomy. METHODS Measured parameters included lateral recess line (LRL) width, distance between LRL and endplates of upper intervertebral disc, superior and lateral angles of interlaminar window, interlaminar height, and interpedicular distance via optimized coronal oblique projection computed tomography images. Measurements were performed at L2, L3, L4, and L5 levels. RESULTS LRL was found to be 16.3 ± 3.4 mm, 17.3 ± 3.3 mm, 21.7 ± 3.4 mm, and 27.7 ± 4.0 mm at L2, L3, L4, and L5. The distances between LRL and both upper endplates decreased from L2 to L5. Distance between LRL and upper endplate of same vertebra and between LRL and lower endplate of upper vertebra was measured. Interlaminar window height decreased from L2 to L5 levels (from 14.0 ± 4.1 mm to 11.1 ± 2.4 mm). CONCLUSIONS This study showed that width of LRL increases in lower lumbar segments, and height of interlaminar window increases in upper lumbar segments. This study also revealed that intervertebral disc is located cranial to LRL at L2-3, L3-4, and L4-5 levels and is located caudal to LRL at L5-S1 level. The results of this study may help surgical planning in both endoscopic and microscopic interlaminar surgery.


Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine | 2018

Comparison of rigid and semi-rigid instrumentation under acute load on vertebrae treated with posterior lumbar interbody fusion/transforaminal lumbar interbody fusion procedures: An experimental study

Mehmet Resid Onen; Cemile Başgül; Ilhan Yilmaz; Mustafa Özkaya; Teyfik Demir; Sait Naderi

Rigid and semi-rigid fixations are investigated several times in order to compare their biomechanical stability. Interbody fusion techniques are also preferable for maintaining the sagittal balance by protecting the disk height. In this study, the biomechanical comparison of semi-rigid and rigid fixations with posterior lumbar interbody fusion or transforaminal lumbar interbody fusion procedures is conducted under trauma. There were four different test groups to analyze the effect of acute load on treated ovine vertebrae. First and second groups were fixed with polyetheretherketone rods and transforaminal lumbar interbody fusion and posterior lumbar interbody fusion cages, respectively. Third and fourth groups were fixed with titanium rods and posterior lumbar interbody fusion and transforaminal lumbar interbody fusion cages, respectively. The drop tests were conducted with 7 kg weight. There were six samples in each group so the drop test repeated 24 times in total. The test samples were photographed and X-rayed (laterally and anteroposteriorly) before and after drop test. Two fractures were observed on group 1. Conversely, there were no fractures observed for group 2. There were no anterior element fractures for both groups 1 and 2. However, one fracture seen on group 3 was anterior element fracture, whereas the other three were posterior element fractures. All three fractures were anterior element fractures for group 4. Treated vertebrae with polyetheretherketone rods and posterior lumbar interbody fusion cages showed the best durability to the drop tests among the groups. Semi-rigid fixation gave better results than rigid fixation according to failed segments. Posterior lumbar interbody fusion cages seem to be better option for semi-rigid fixation, however mentioned surgical disadvantages must be considered.


Journal of Clinical Neuroscience | 2015

Reliability and effectiveness of percutaneous sacroplasty in sacral insufficiency fractures

Mehmet Resid Onen; Evren Yuvruk; Sait Naderi


Clinical spine surgery | 2018

Downward Laminotomy Technique for Hidden Zone Foraminal Disk Herniations: Technical Notes and Preliminary Results

Sait Naderi; Mehmet Resid Onen


World Neurosurgery | 2017

Inverse Association Between Basilar Artery Volume and Neuron Density in the Stellate Ganglion Following Bilateral Common Carotid Artery Ligation: An Experimental Study

Ilhan Yilmaz; Metehan Eseoglu; Mehmet Resid Onen; Osman Tanriverdi; Mustafa Kilic; Adem Yilmaz; Ahmet Murat Müslüman; Mehmet Dumlu Aydin; Cemal Gundogdu

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Ilhan Yilmaz

University of Texas Southwestern Medical Center

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Ulas Cikla

University of Wisconsin-Madison

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Ayhan Kanat

Recep Tayyip Erdoğan University

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Abdulbaki Kozan

University of Wisconsin-Madison

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Mustafa K. Başkaya

University of Wisconsin-Madison

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