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Robert F. Heary

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Taşkan Akdeniz, Tuncay Kaner, İbrahim Tutkan and Ali Fahir Ozer

Object

In most cases of lumbar disc herniation, the primary problem is usually limited to radicular pain due to nerve compression on the herniated side, which is generally limited to the side of operation. The aim of this study was to reevaluate the side of the surgical approach in a selected group of patients with leg pain and contralateral lumbar disc herniation.

Methods

Included in this study were a total of 5 patients with lumbar disc herniations who presented with contralateral symptoms and neurological signs. In all cases, patients underwent a microdiscectomy from the side ipsilateral to the herniated lumbar disc, the side contralateral to the motor deficits and leg pain.

Results

The symptoms and signs, to some extent, resolved during the immediate postoperative period. There were no postoperative complications.

Conclusions

The findings confirm that performing a laminotomy via the side of the herniation is sufficient for this group of patients.

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Yunus Alapan, Cihan Demir, Tuncay Kaner, Rahmi Guclu and Serkan İnceoğlu

Object

The goal of this study was to investigate the effect of ligament failure on the instantaneous center of rotation (ICR) in the lower lumbar spine.

Methods

A 3D finite element model of the L4–5 segment was obtained and validated. Ligament failure was simulated by reducing ligaments in a stepwise manner from posterior to anterior. A pure bending moment of 7.5 Nm was applied to the model in 3 anatomical planes for the purpose of validation, and a 6-Nm moment was applied to analyze the effect of ligament failure. For each loading case, ligament reduction step, and load increment, the range of motion of the segment and the ICR of the mobile (L-4) vertebra were calculated and characterized.

Results

The present model showed a consistent increase in the range of motion as the ligaments were removed, which was in agreement with the literature reporting the kinematics of the L4–5 segment. The shift in the location of the ICR was below 5 mm in the sagittal plane and 3 mm in both the axial and coronal planes.

Conclusions

The location of the ICR changed in all planes of motion with the simulation of multiple ligament injury. The removal of the ligaments also changed the load sharing within the motion segment. The change in the center of rotation of the spine together with the change in the range of motion could have a diagnostic value, revealing more detailed information on the type of injury, the state of the ligaments, and load transfer and sharing characteristics of the segment.

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Yunus Alapan, Semih Sezer, Cihan Demir, Tuncay Kaner and Serkan İnceoğlu

Object

The center (axis) of rotation (COR) in the lumbar spine has been studied well. However, there is limited information on the kinetic and kinematic consequences of imposed shift in the location of the COR, although this type of shift can be seen after surgeries using motion preservation or dynamic stabilization devices. The objective of this study was to assess the kinetic and kinematic changes in the lumbar spinal segment due to various imposed CORs.

Methods

A 3D finite element model of the L4–5 segment was constructed and validated. The segment was loaded under a 7.5-Nm bending moment while constrained to rotate about various imposed CORs in the sagittal and axial motion planes. Range of motion, ligament forces, facet loads, and disc stresses were measured.

Results

The present model showed an agreement with previous in vitro and finite element studies under the same load and boundary conditions. Range of motion, facet forces, disc stresses, and ligament loads showed a strong association with the location of the COR.

Conclusions

Acute alterations in the location of the COR can significantly change the load sharing characteristics within the spine segment. The normal location of the COR is a result of the tendency of the vertebra to move in the path of least cumulative resistance.

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Erkın Sonmez and Hakan Caner

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Murat Cosar, Mehdi Sasani, Tunc Oktenoglu, Tuncay Kaner, Omur Ercelen, K. Cagri Kose and A. Fahir Ozer

Object

Vertebroplasty is a well-known technique used to treat pain associated with vertebral compression fractures. Despite a success rate of up to 90% in different series, the procedure is often associated with major complications such as cord and root compression, epidural and subdural hematomas (SDHs), and pulmonary emboli, as well as other minor complications. In this study, the authors discuss the major complications of transpedicular vertebroplasty and their clinical implications during the postoperative course.

Methods

Vertebroplasty was performed in 12 vertebrae of 7 patients. Five patients had osteoporotic compression fractures, 1 had tumoral compression fractures, and 1 had a traumatic fracture. Two patients had foraminal leakage, 1 had epidural leakage, 1 had subdural cement leakage, 2 had a spinal SDH, and the last had a split fracture after the procedure.

Results

Three patients had paraparesis (2 had SDHs and 1 had epidural cement leakage), 3 had root symptoms, and 1 had lower back pain. Two of the 3 patients with paraparesis recovered after evacuation of the SDH and subdural cement; however, 1 patient with paraparesis did not recover after epidural cement leakage, despite cement evacuation. Two patients with foraminal leakage and 1 with subdural cement leakage had root symptoms and recovered after evacuation and conservative treatment. The patient with the split fracture had no neurological symptoms and recovered with conservative treatment.

Conclusions

Transpedicular vertebroplasty may have major complications, such as a spinal SDH and/or cement leakage into the epidural and subdural spaces, even when performed by experienced spinal surgeons. Early diagnosis with CT and intervention may prevent worsening of these complications.

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Tuncay Kaner, Tolga Karadag, Bayram Cirak, Haydar Ali Erken, Aysun Karabulut, Yilmaz Kiroglu, Semih Akkaya, Feridun Acar, Erdal Coskun, Osman Genc and Nagihan Colakoglu

Object

Even though there have been many efforts to recover neuronal dysfunction following spinal cord injuries, there are limitations to the treatment of these injuries. The purpose of this laboratory investigation was to determine the clinical and neurophysiological effects of human umbilical cord blood (HUCB) transplantation in a rat hemisection model of spinal cord injury.

Methods

In this study, experimental hemisection of the thoracic spinal cord was performed in rats. The rats were divided into 4 groups (6 rats in each group). One group of rats (Group 1) underwent thoracic laminectomy only. Rats in Group 2 underwent laminectomy and right hemisection of the thoracic spinal cord. Rats in Group 3 underwent right hemisection and implantation of freshly obtained HUCB on Day 0 postinjury. Rats in Group 4 underwent hemisection and implantation of freshly obtained HUCB on Day 4 postinjury. Clinical evaluations of rat motor function included the following: neurological examination, Rotarod performance, and inclined plane tests. Rats also underwent reflex evaluation.

Results

The neurological examinations revealed that the frequency of plegic rats was 70.8% at the beginning of the study across all 4 groups; this value decreased to 20.8% by the end of the study. The percentage of rats with a normal examination increased from 25% to 50%. The results of Rotarod performance and 8-week inclined plane performance tests showed statistical significance (p < 0.05) in an overall group comparison across all time points. At the end of the 8 weeks, a statistically significant difference was found in the inclined plane test results between rats in Groups 1 and 2. There were no statistically significant differences between Groups 1, 3, and 4 (p < 0.05). When the reflex responses of the hemisectioned sides were compared, statistically significant differences were detected between groups (p < 0.05). All groups were significantly different with regard to the right-side reflex response score (p < 0.05). Spinal cord preparations of rats in all groups were examined for histopathological changes.

Conclusions

Human umbilical cord blood is stem cell rich and easily available, and it carries less risk of inducing a graft-versus-host reaction in the recipient. Human umbilical cord blood serum is also noted to contain stem cell–promoting factors, which is why cell isolation was not used in this study. Freshly obtained cord blood was also used because storage of cord blood has been reported to have some negative effects on stem cells. Transplantation of freshly obtained HUCB into the hemisectioned spinal cord experimental model demonstrated clinical and neurophysiological improvement.