Cystic Degeneration of Cerebellar Tonsil 1 Year After Chiari I Malformation Surgery: A Case Report and Review of the Literature.

BACKGROUND: Chiari malformation results from a bony structural anomaly of the skull base. The structural defect causes downward displacement of the cerebellar tonsils through the foramen magnum. The herniated tonsils block the normal flow of cerebrospinal fluid, which causes a wide spectrum of clinical symptoms. CASE REPORT: In May 2015, a 16-year-old girl was referred to our center because of a 1-year history of occipital headache, most often triggered by exercise and physical activity at school. She had experienced new-onset numbness in both hands, more severe on the right side, associated with some degrees of weakness. Eventually, an evaluation of her condition included magnetic resonance imaging in T1 and T2 sequences, which revealed a 20-mm downward migration of the cerebellar tonsils, associated with a cervical cord syrinx at the level of the fourth and fifth cervical vertebrae. The patient underwent posterior fossa decompression and C1 and partial C2 laminectomies. Postoperatively there were no complications, and the patient was discharged on day 3. Postoperatively, she experienced some improvement in her symptoms. After 2 months of routine outpatient follow-up, she was better, the headaches had subsided, she could resume some activities, and there was no paresis in her limbs. CONCLUSIONS: In cases of progressive symptoms of Chiari malformation, surgical decompression is important and should be considered after shunt insertion to the hindbrain.

Spontaneous Epidural Hematoma of Cervical Spine.

Spontaneous cervical epidural hematoma is an uncommon cause of acute spinal cord compression. This is a rare idiopathic condition that leads to acute onset of neurologic deficits, which if not recognized early can have catastrophic consequences. Acute cervical epidural hematoma is definitely a condition of neurologic emergency. Although it is a rare condition, it must be considered in nontraumatic patients with sudden onset of neurologic deficits. Patients with spontaneous spinal epidural hematoma typically present with acute onset of severe back pain, and they rapidly develop signs of compression of the spinal cord or cauda equina. Here, we present a case of a 31-year-old man who presented with acute onset of neck pain with radicular component with progressive neurologic deficit. Emergent magnetic resonance imaging revealed cervical extradural hematoma with cord compression that was promptly evacuated. Functional recovery was achieved within 48 hours. The level of preoperative neurologic deficit and its severity, as well as operative interval, are important factors significantly affecting the postoperative outcome.

Ligamentum Flavum Hematoma Presented with Low Back Pain: A Case Report and Review of the Literature.

A 61-year-old woman with no past medical history presented with low back pain and radicular pain in the right lower extremity. Magnetic resonance imaging of the lumbar spine showed a heterogeneous intensity mass in the lateral recess of the spinal canal at the L4-5 disk level. Postoperatively, her radicular pain resolved within a few days with excellent low back pain relief. Ligamentum flavum hematoma is a rare differential diagnosis for cystic lesions in the lumbar spine that can be removed simply by surgery with excellent relief of symptoms and improvement in strength of the right lower extremity and increased sensitivity.

Three-dimensional transformation optics for arbitrary coordinate systems: transforming conductive materials and boundaries.

A three-dimensional transformation optics method, leading to homogeneous materials, applicable to any non-Cartesian coordinate systems or waveguides/objects of arbitrary cross-sections is presented. Both the conductive boundary and internal material of the desired device is determined by the proposed formulation. The method is applicable to a wide range of waveguide, radiation, and cloaking problems, and is demonstrated for circular waveguide couplers and an external cloak. An advantage of the present method is that the material properties are simplified by appropriately selecting the conductive boundaries. For instance, a right-angle circular waveguide bend is presented which uses only one homogenous material. Also, transformation of conductive materials and boundaries are studied. The conditions in which the transformed boundaries remain conductive are discussed. In addition, it is demonstrated that negative infinite conductivity can be replaced with positive conductivity, without affecting the field outside the conductive boundary. It is also observed that a negative finite conductivity can be replaced with a positive one, by accepting some small errors. The general mathematical procedure and formulation for calculating the parametric surface equations of the conductive peripheries are presented.

Textiloma: A Case of Foreign Body Mimicking a Spinal Tumor.

STUDY DESIGN: Case report OBJECTIVE.: To report a case of foreign body mimicking spinal tumor. SUMMARY OF BACKGROUND DATA: Gossypiboma or more broadly retained foreign object is a surgical complication resulting from foreign materials such as cotton or gauze pads and surgical sponge, accidentally left inside a patient's body. Such foreign materials cause foreign body reaction in the surrounding tissue. METHODS: A retrospective case report was performed. Informed consent was obtained from patient. RESULTS: We describe a case of textiloma in which the patient presented with low back pain and radiculopathy 12 years after L5\S1 discectomy. Imaging revealed a round mass lesion in the sacral space. CONCLUSION: At the end of surgery, the operative site should be flushed with saline and carefully examined for any foreign materials. LEVEL OF EVIDENCE: 4.