Interferons (IFNs) are the most important cytokines in antiviral immune responses. “Natural IFN-producing cells” (IPCs) in human blood express CD4 and major histocompatibility complex class II proteins, but have not been isolated and further characterized because of their rarity, rapid apoptosis, and lack of lineage markers. Purified IPCs are here shown to be the CD4+CD11c− type 2 dendritic cell precursors (pDC2s), which produce 200 to 1000 times more IFN than other blood cells after microbial challenge. pDC2s are thus an effector cell type of the immune system, critical for antiviral and antitumor immune responses.

https://science.sciencemag.org/content/sci/284/5421/1835.full.pdf

The nature of the principal type 1 interferon-producing cells in human blood.

Study design Review of the literature. Objectives Review the definition, etiology, incidence, and risk factors associated with as well as potential treatment options. Summary of background data The development of pathology at the mobile segment next to a lumbar or lumbosacral spinal fusion has been termed adjacent segment disease. Initially reported to occur rarely, it is now considered a potential late complication of spinal fusion that can necessitate further surgical intervention and adversely affect outcomes. Methods MEDLINE literature search. Results The most common abnormal finding at the adjacent segment is disc degeneration. Biomechanical changes consisting of increased intradiscal pressure, increased facet loading, and increased mobility occur after fusion and have been implicated in causing adjacent segment disease. Progressive spinal degeneration with age is also thought to be a major contributor. From a radiographic standpoint, reported incidence during average postoperative follow-up observation ranging from 36 to 369 months varies substantially from 5.2 to 100%. Incidence of symptomatic adjacent segment disease is lower, however, ranging from 5.2 to 18.5% during 44.8 to 164 months of follow-up observation. The rate of symptomatic adjacent segment disease is higher in patients with transpedicular instrumentation (12.2-18.5%) compared with patients fused with other forms of instrumentation or with no instrumentation (5.2-5.6%). Potential risk factors include instrumentation, fusion length, sagittal malalignment, facet injury, age, and pre-existing degenerative changes. Conclusion Biomechanical alterations likely play a primary role in causing adjacent segment disease. Radiographically apparent, asymptomatic adjacent segment disease is common but does not correlate with functional outcomes. Potentially modifiable risk factors for the development of adjacent segment disease include fusion without instrumentation, protecting the facet joint of the adjacent segment during placement of pedicle screws,fusion length, and sagittal balance. Surgical management, when indicated, consists of decompression of neural elements and extension of fusion. Outcomes after surgery, however, are modest.

Adjacent segment disease after lumbar or lumbosacral fusion: review of the literature.

Background Because clinicians fear missing occult cervical-spine injuries, they obtain cervical radiographs for nearly all patients who present with blunt trauma. Previous research suggests that a set of clinical criteria (decision instrument) can identify patients who have an extremely low probability of injury and who consequently have no need for imaging studies. Methods We conducted a prospective, observational study of such a decision instrument at 21 centers across the United States. The decision instrument required patients to meet five criteria in order to be classified as having a low probability of injury: no midline cervical tenderness, no focal neurologic deficit, normal alertness, no intoxication, and no painful, distracting injury. We examined the performance of the decision instrument in 34,069 patients who underwent radiography of the cervical spine after blunt trauma. Results The decision instrument identified all but 8 of the 818 patients who had cervical-spine injury (sensitivity, 99.0 ...

https://www.nejm.org/doi/pdf/10.1056/NEJM200007133430203

Validity of a set of clinical criteria to rule out injury to the cervical spine in patients with blunt trauma. National Emergency X-Radiography Utilization Study Group.

The invention relates to a spinal disc endoprosthesis. The endoprosthesis has a resilient body formed of one or more materials which may vary in stiffness from a relatively stiff exterior annular gasket portion to a relatively supple central nucleus portion. Concaval-convex elements at least partly surround that nucleus portion so as to retain the nucleus portion and gasket between adjacent vertebral bodies in a patient's spine. Assemblies of endoprosthetic discs, endoprosthetic vertebral bodies, and endoprosthetic longitudinal ligaments may be constructed. To implant this endoprosthesis assembly, information is obtained regarding the size, shape, and nature of a patient's damaged spine. Thereafter, one or more prosthetic vertebral bodies and disc units are constructed in conformity with that information. Finally, the completed and conformed vertebral body and disc assembly is implanted in the patient's spine.

Human spinal disc prosthesis

A spine distraction implant alleviates pain associated with spinal stenosis and facet arthropathy by expanding the volume in the spine canal and/or neural foramen. The implant provides a spinal extension stop while allowing freedom of spinal flexion.

Spine distraction implant and method

Disclosed are prosthetic devices for insertion into intervertebral disc spaces after the removal of an intervertebral disc or after a corpectomy. Specifically, intervertebral devices having fixed shapes for accommodating the defined surface contours of vertebral endplates are disclosed. Also disclosed are intervertebral devices formed of osteoinductive materials, such as bone growth factors, to facilitate bone growth. A method for quantitatively determining the three-dimensional morphology of vertebral surfaces, particularly vertebral endplates, is also disclosed.

Prosthetic intervertebral devices

This invention is for devices and methods for modular occipital/spinal fixation, general bone fixation and skull fracture repair. An orthopedic plate (100) designed for unicortical engagement of the occiput exhibits greater stability and safety over conventional devices. A locking screw/plate assembly (20) for posterior facet screw fixation of cervical and thoracic vertebrae are also disclosed. A locking screw (30) and locking tool (40) may be used with the orthopedic plate and spinal fixation devices as well as other orthopedic devices.

Devices and methods for posterior spinal fixation

A rod-based orthopedic fixation system, in particular a spinal fixation system, comprising orthopedic fasteners which utilize a novel set screw system for securing a cylindrical longitudinal member or orthopedic fixation rod to the fastener. Also disclosed are transverse extension devices useful for connecting a spinal fixation rod to an orthopedic fastener to minimize rod contouring in both the frontal and sagittal planes.

Orthopedic fixation system

The authors performed a retrospective review of 32 patients who had undergone a single-level anterior lumbar fusion with femoral strut allograft as an isolated procedure. The goal of the study was to use clinical radiographs to measure interspace distraction, graft subsidence, interspace collapse, the nature of allograft incorporation, and to correlate these results with successful arthrodesis. Results were categorized according to plain radiographic appearance and flexion/extension stability. Sixty-six percent of the group exhibited radiographic union with flexion/extension stability. Twenty-two percent exhibited stability on the flexion-extension analysis but less than complete arthrodesis was present. Twelve percent exhibited radiographic non-union and flexion-extension instability. Interspace distraction of 11 mm was obtained initially with a follow-up distraction of 5.5 mm. Graft subsidence was noted posteriorly in 27 patients with an average subsidence of 4 mm. The authors' conclusions were: 1) Interspace distraction can be achieved with anterior lumbar fusion if appropriate interbody grafts are used. 2) Despite a solid arthrodesis rate of only 66%, "functional arthrodesis" was achieved in 88%. In a retrospective review of patients who underwent anterior lumbar fusion with femoral strut allograft, interspace distraction, graft subsidence, and incorporation and arthrodesis status were measured. A solid arthrodesis was achieved in 66% of the patients, and functional arthrodesis in another 22%. Interspace distraction was maintained in 59% of cases.

Interspace Distraction and Graft Subsidence After Anterior Lumbar Fusion With Femoral Strut Allograft

Thoracolumbar cadaver spine segments were studied by biplane radiography techniques during intradiscal injection of radiographic contrast agent. In these radiographically nondegenerated discs, significant deformation of the end plate accompanied these in vitro discograms. End plate deflections averaged 0.3 mm. The intervertebral disc bulges averaged 0.5 mm. These results suggest that the end plate itself, or events within the bone, are possible pain sources during clinical discography.

Discography causes end plate deflection.

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