Upper cervical myelopathy due to arachnoiditis and spinal cord tethering from adjacent C-2 osteomyelitis. Case report and review of the literature.

Myelopathy caused by a spinal cord infection is typically related to an adjacent compressive lesion such as an epidural abscess. The authors report a case of progressive high cervical myelopathy from spinal cord tethering caused by arachnoiditis related to an adjacent C-2 osteomyelitis. This 70-year-old woman initially presented with a methicillin-sensitive Staphylococcus aureus osteomyelitis involving the C-2 odontoid process. She was treated with appropriate antibiotic therapy but, over the course of 4 weeks, she developed progressive quadriparesis. A magnetic resonance image revealed near-complete resolution of the C-2 osteomyelitis, but new ventral tethering of the cord was observed at the level of the odontoid tip. She subsequently underwent open surgical decompression and cord detethering. Postoperatively she experienced improvement in her symptoms and deficits, which continued to improve 1 year after her surgery. To the authors' knowledge, this is the first reported case of progressive upper cervical myelopathy due to arachnoiditis and cord tethering from an adjacent methicillin-sensitive S. aureus C-2 osteomyelitis.

Reverse Thermal Gel for In Utero Coverage of Spina Bifida Defects: An Innovative Bioengineering Alternative to Open Fetal Repair.

Current state-of-the-art management of open spina bifida defects entails an open fetal surgery approach associated with significant morbidities. In an attempt to reduce these risks and provide for an earlier minimally invasive repair, it is aimed to develop and characterize an innovative alternative using a unique reverse thermal gel. This study focuses on characterization of the physical and biological properties of the polymer and its in vivo applicability. Based on the knowledge and benchmarking, the "ideal" biomaterial should have the following characteristics: stability in amniotic fluid, limited permeability, biocompatibility, biologically functional, nontoxic, ability to support cellular functions, and in vivo applicability. The results demonstrate that the polymer possesses a unique ultrastructure, is stable in amniotic fluid, possesses limited yet predictable permeability, biocompatible with cells exposed in neural tube defects, is nontoxic, and can support cellular migration. These characteristics make it a potential novel alternative to open fetal repairs.

An alternative to the classical nerve graft for the management of the short nerve gap.

Reconstruction of a short nerve gap by a nerve graft produces donor-site scarring, loss of donor nerve function, and neuroma formation. This study compared the regeneration achieved after 1 year in 16 monkeys across a 3-cm upper arm ulnar nerve gap with a bioabsorbable polyglycolic acid nerve conduit with the regeneration achieved with a classical interfascicular interpositional sural nerve graft. The results demonstrated electrophysiologic and histologic evidence of neural regeneration across the gaps in all experimental groups. The bioabsorbable nerve conduit groups and the sural nerve graft group had mean fiber diameters, amplitudes, and conduction velocities each significantly less than those of normal control ulnar nerves. There was, however, no significant difference between any of the experimental groups. Electromyography demonstrated recovery of 19 of the 28 (68 percent) intrinsic muscles studied. These results demonstrate that the primate peripheral nerve can regenerate across short nerve gaps when guided by an appropriate nerve conduit, suggesting that a single-stage biodegradable polyglycolic acid conduit may be used as an alternative to a short interfascicular nerve graft.

Use of a synthetic dural substitute to prevent ventral retethering in the management of diastematomyelia.

Diastematomyelia is a congenital condition where the spinal cord is split by a bony or cartilaginous septum. Neurological signs and symptoms arise when this septum tethers the spinal cord. Surgical detethering often improves symptoms; however, recurrent tethering of the cord is increasingly recognised as a long-term complication. In order to prevent retethering many techniques have been used, including early patient mobilisation and sectioning of the cord. Dorsal expansile duroplasty, using synthetic grafts, is a commonly used technique to prevent recurrent dorsal tethering. We present a 31-year-old woman with recurrent ventral tethering of the cord where we used expanded polytetrafluoroethylene (Gore Preclude MVP Dura Substitute; WL Gore and Associates, Flagstaff, AZ, USA) to cover the ventral dural surface, separating the cord from its dural site of tethering. This technique may be useful to prevent ventral retethering in diastematomyelia.

Histological evaluation of acute covering of an experimental neural tube defect with biomatrices in fetal sheep.

OBJECTIVE: The aim of the study was to determine the histological effect on the neural tissue of in utero covering of an experimental neural tube defect in fetal lambs, with the use of two different biomatrices. MATERIALS AND METHODS: In 23 fetal sheep, surgery was performed at 79 days' gestation. In 19 of these, a neural tube defect was created, while 4 fetuses served as sham-operated controls. In 7 of the 19 operated fetuses the defect was left uncovered. In the remaining 12 animals the defect was covered either with a collagen biomatrix (4 animals), skin (3 animals), or small intestinal submucosa biomatrix (5 animals). The lambs were sacrificed at 1 week of age and histological examination was performed. RESULTS: All lambs with an uncovered neural tube defect showed histological damage of the spinal cord. In lambs in which the neural tube defect was covered, one half showed a normal architecture of the spinal cord while minor histological damage was present in the other half. Between the three groups in which the defect was covered, the histological outcome was comparable. CONCLUSIONS: Acute covering of an experimental neural tube defect in fetal lambs prevents severe histological damage to the spinal cord independent of the two biomatrices used in this study.

In utero repair of an experimental neural tube defect in a chronic sheep model using biomatrices.

OBJECTIVE: Persistent exposure of the unprotected spinal cord to amniotic fluid and the uterine wall can lead to progressive damage of neural tissue in case of a myelomeningocele (two-hit hypothesis). The aim of this study was to evaluate whether in utero repair of an experimental neural tube defect in a fetal lamb could protect neural tissue from secondary injury and save neurologic functions after birth. METHODS: In 19 fetal lambs, a neural tube defect was created at 79 days' gestation. In 12 lambs the defect was covered either with a novel, molecular defined collagen-based biocompatible and biodegradable matrix (UMC) or with a small intestinal submucosa (SIS) biomatrix (Cook) or by closing the skin over the defect. RESULTS: All lambs with the defect covered showed no or minor neurologic morbidity in contrast to the lambs with the defect uncovered in which major neurologic morbidity was seen. CONCLUSIONS: These results demonstrate that long-term exposure of the open spinal cord to the intrauterine environment can lead to damage of neural tissue and, consequently loss of neurologic functions and that coverage of the defect can lead to a better neurologic outcome. Furthermore, we could show that a UMC biomatrix and an SIS biomatrix are useful for in utero coverage of a surgically created neural tube defect in our model.