Finite Element Analysis of Short- Versus Long-Segment Posterior Fixation for Thoracolumbar Burst Fracture.

OBJECTIVE: The thoracolumbar (TL) area marks the transition of the rigid thoracic spine into the mobile lumbar spine, and it is considered to be the weakest part of the spine. This study was designed to develop a finite element (FE) model of the TL junction (T9-L3) to provide data that could help the clinician and researcher to answer the question of whether short-segment posterior fixation is sufficient for biomechanical performance. In addition, the aim was to examine whether long-segment posterior fixation carries a greater risk of the development of adjacent segment disease. METHODS: This was a biomechanical finite element model analysis. FE analysis of the spine was conducted with posterior instrumentation under multidirectional loading conditions in order to evaluate the kinematics of the instrumented lumbar spine, as well as stresses in the posterior spinal instrumentation. We analyzed the following: 1) the range of motion of the T9-L3 region; and 2) the von Mises stress nephograms of the pedicle screws, rods, vertebrae, endplates, and intervertebral discs of 2 fixation FE models. RESULTS: Long-segment stabilization was found to be beneficial in terms of reducing total stress on the spine. However, it is possible to reduce the stress on the system by incorporating the spinal fracture into the stabilization system. Therefore, short-segment stabilization is sufficient to create a safe and robust stabilization system and to maintain neighboring intact vertebrae. CONCLUSIONS: Short-segment posterior fixation is sufficient to stabilize fractures at the TL junction, where the spinal fracture is included in the stabilization system.

Intradural solitary fibrous tumor of the lumbar spine: a distinctive case report.

Background. Solitary fibrous tumors are ubiquitous mesenchymal neoplasms of putative fibroblastic origin. They were originally described in the pleura but subsequently have been reported in many extraserosal sites. Solitary fibrous tumors may also occur in the meninges, central nervous system parenchyma, and spinal cord. Case. A 67-year-old male patient with progressive lower extremity weakness, urinary urgency, and sexual dysfunction has been admitted to our hospital. On his lumbar MRI, we detected an intradural lesion posterior to the L3 vertebral corpus. We resected the lesion by L3 total laminectomy. Immunohistological findings revealed strong and diffuse immunopositivity with vimentin, CD34, and bcl-2. Ki-67 proliferation index was 5-8%. We did not detect any recurrence 12 months after his operation. Conclusion. SFT is mostly seen in young and middle-aged patients and should be considered among differential diagnosis in cases suffering from pain, hypoesthesia, and urinary dysfunction. Gross total resection should be primary treatment. Tumors that have high Ki-67 labeling should be followed up for potential recurrences.

Spinal arachnoid cyst associated with arachnoiditis following subarachnoid haemorrhage in adult patients: A case report and literature review.

OBJECTIVE: Arachnoiditis is an inflammatory process resulting with the fibrosis of arachnoid mater. It can vary in severity from mild thickenings to catastrophic adhesions that ruins subarachnoid space. As a result, arachnoid cysts can be formed. Arachnoid cyst induced by symptomatic spinal arachnoiditis is a rare complication of subarachnoid haemorrhages. In this article, we aimed to present a case of spinal arachnoid cyst formation following subarachnoid haemorrhage and examine similar cases in the literature. CASE REPORT: Forty-six years old, previously healthy female patient has been treated medically for headaches due to perimesencephalic subarachnoid bleeding. Approximately two and a half months later, she started to have severe headaches and diplopia. We detected hydrocephalus and performed ventriculoperitoneal shunt surgery. Two months later, she started to have complaints of weakness in her lower extremities. On neurological examination, she had paraparesis and on spinal magnetic resonance imaging she had an arachnoid cyst lengthening from C7 to T2 and compressing the spinal cord posteriorly. We performed partial laminectomy, drainage of arachnoid cyst and replacement of cystopleural T tube shunt. On follow-up, her lower extremity strength has ameliorated. She was taken into a physical therapy and rehabilitation programme. Three months later she was able to walk with a crutch. CONCLUSION: Subarachnoiditis and associated arachnoid cyst can cause severe morbidity. This rare situation (which especially occurs following subarachnoid haemorrhage of posterior fossa) should be known and physicians should keep in mind that it requires urgent surgical procedure.

Monostotic fibrous dysplasia involving occipital bone: a case report and review of literature.

Fibrous dysplasia (FD) is a progressive systemic bone tumour of young and it can be seen on cranial bones. FD is divided into three types according to radiological features. The second most common subtype is polyostotic subtype. With this article, we aimed to review and present clinical features, radiological examination, differential diagnosis and treatment management of a case of solitary monostotic fibrous dysplasia of occipital bone. 15 years old female patient admitted to our hospital for a bump and in the back of his head that she noticed 1 month ago. Her physical and neurological examination was normal. On cranial CT examination we detected a bony defect. Her gadolinium enhanced cranial MRI revealed bony defect along with massive gadolinium enhancement in adjacent tissue. On histopathologic examination; PANCK, CD68, CD1a were found negative and CD45, S-100, Vimentine were found positive. Ki-67 was 4,8%. In conclusion, fibrous dysplasia is a progressive bone disease of the young patients. Despite its resemblance to a benign lesion by not being symptomatic it can progress and cause severe bony defects and skin lesions. Total surgical resection is necessary and sufficient for total treatment.

A new entity: Chiari Zero malformation and its surgical method.

Recently, Iskandar et al described "Chiari Zero malformation" to characterize some kind of syringomyelia that exhibits classic Chiari-type symptoms with little to no herniation, but there is some dilemma about whether it is actually present. We presented a 38-year-old-man with a diagnosis of cervical syringomyelia. In his neurological examination, there was monoparesia at the left leg together with hypoesthesia below thoracal 7. He had initially been treated with syringopleural shunting successfully. Nine months after surgery, his syringomyelia had regrown and he clinically deteriorated. It was accepted as "a Chiari zero malformation". We performed craniovertebral decompression only. Although there was no tonsillar herniation, his syringomyelia was completely resolved and his neurological status was improved six months after the craniovertebral decompression, This case suggested that "Chiari zero malformation" description is remarkable and craniovertebral decompression is a suitable surgical approach for this entity.