Full-scale three-dimensional (3D) models offer a useful tool in preoperative planning, allowing full-scale stereoscopic recognition from any direction and distance with tactile feedback. Although skills and implants have progressed with various innovations, rheumatoid cervical spine surgery remains challenging. No previous studies have documented the usefulness of full-scale 3D models in this complicated situation. The present study assessed the utility of full-scale 3D models in rheumatoid cervical spine surgery. Polyurethane or plaster 3D models of 15 full-sized occipitocervical or upper cervical spines were fabricated using rapid prototyping (stereolithography) techniques from 1-mm slices of individual CT data. A comfortable alignment for patients was reproduced from CT data obtained with the patient in a comfortable occipitocervical position. Usefulness of these models was analyzed. Using models as a template, appropriate shape of the plate-rod construct could be created in advance. No troublesome Halo-vests were needed for preoperative adjustment of occipitocervical angle. No patients complained of dysphasia following surgery. Screw entry points and trajectories were simultaneously determined with full-scale dimensions and perspective, proving particularly valuable in cases involving high-riding vertebral artery. Full-scale stereoscopic recognition has never been achieved with any existing imaging modalities. Full-scale 3D models thus appear useful and applicable to all complicated spinal surgeries. The combination of computer-assisted navigation systems and full-scale 3D models appears likely to provide much better surgical results.
Few reports about clinical experience in arthroscopy of finger joints exist. Furthermore, little attention has been given to arthroscopic synovectomy of rheumatoid fingers. Herein, we describe our experience with arthroscopic synovectomy of metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints in patients with rheumatoid arthritis.Arthroscopic synovectomy was performed in 45 finger joints (18 MCP joints, 26 PIP joints, and 1 interphalangeal thumb joint) of 23 patients with rheumatoid arthritis. All procedures were performed on an outpatient basis under regional anesthesia. The diameter of the arthroscope for small joints was 1.5 mm, and a mini shaver system with a 2.5-mm cutter was used for synovectomy. We developed new portals for PIP joints that were established on the dorsolateral aspect at a position more lateral than previously reported portals.Intraarticular structures of finger joints were well visualized, and magnified observation of the articular cartilage and synovial membrane was possible. Because insertion of the instruments into the palmar cavity was not possible without causing damage to the articular surfaces, synovectomy of the palmar capsule could not be performed. However, arthroscopic synovectomy of the dorsal capsule under visual control could be safely performed using the 2-portal technique. None of the patients experienced postprocedural complications. Swelling of each joint disappeared after the procedure and did not return in many cases for a long period. Furthermore, no joints required reoperation.We conclude that arthroscopy of MCP and PIP joints is useful not only for the assessment of articular cartilage and synovium but also for synovectomy in rheumatoid arthritis.
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