Polarized illumination coded structured illumination microscopy (picoSIM): experimental results.

The need for acquiring at least three images to reconstruct an optical section of a sample limits the acquisition rate in structured illumination microscopy (SIM) for optical sectioning. In polarized illumination coded structured illumination microscopy (picoSIM) the three individual light patterns are encoded in a single polarized illumination light distribution, enabling the acquisition of the complete SIM data in a single exposure. Here, we describe our experimental set-up and show experimental results acquired with sequential and single-shot picoSIM. This article is part of the Theo Murphy meeting issue 'Super-resolution structured illumination microscopy (part 2)'.

Two-millimetre diameter operative arthroscopy of the ankle is safe and effective.

PURPOSE: Technical innovation now offers the possibility of 2-mm diameter operative arthroscopy: an alternative to conventional arthroscopy that no longer uses inner rod-lenses. The purpose of this study was to assess whether all significant structures in the ankle could be visualized and surgically reached during 2-mm diameter operative arthroscopy, without inflicting iatrogenic damage. METHODS: A novel, 2-mm diameter arthroscopic system was used to perform a protocolled arthroscopic procedure in 10 fresh-frozen, human donor ankles. Standard anteromedial and anterolateral portals were utilized. Visualization and reach with tailored arthroscopic instruments of a protocolled list of articular structures were recorded and documented. A line was etched on the most posterior border of the talar and tibial cartilage that was safely reachable. The specimens were dissected and distances between portal tracts and neurovascular structures were measured. The articular surfaces of talus and tibia were photographed and inspected for iatrogenic damage. The reachable area on the articular surface was calculated and analysed. RESULTS: All significant structures were successfully visualized and reached in all specimens. The anteromedial portal was not in contact with neurovascular structures in any specimen. The anterolateral portal collided with a branch of the superficial peroneal nerve in one case but did not cause macroscopically apparent harm. On average, 96% and 85% of the talar and tibial surfaces was reachable respectively, without causing iatrogenic damage. CONCLUSION: 2-mm diameter operative arthroscopy provides safe and effective visualization and surgical reach of the anterior ankle joint. It may hold the potential to make ankle arthroscopy less invasive and more accessible.

2-Mm Diameter Operative Tendoscopy of the Tibialis Posterior, Peroneal, and Achilles Tendons: A Cadaveric Study.

BACKGROUND: Technical innovation now offers the possibility of 2-mm-diameter operative tendoscopy with disposable arthroscopes and tablet-like control units. The promises of new technology should be critically scrutinized. Therefore, this study assessed whether 2-mm-diameter operative tendoscopy of the tibialis posterior, peroneal, and Achilles tendons was safe and effective in a cadaveric model. METHODS: A 2-mm-diameter arthroscopic system was used to perform a tendoscopic procedure in 10 nonpaired, fresh-frozen, human ankles. Standard tendoscopic portals were utilized. Visual examination and operative reach with tailored tendoscopic instruments within the tendon sheaths were recorded and documented. Adhesiolysis and vincula resections were performed. After dissection, distances between portal tracts and neurovascular structures were measured and the tendons were inspected for signs of iatrogenic damage. RESULTS: The entire tendon sheath and tendon of the tibialis posterior, peroneus brevis, and Achilles tendons were visualized and reached with tailored operative instruments. The proximal part of the peroneus longus tendon was visible and reachable from proximally up to the cuboid bone distally. Adhesiolysis and vincula resections were successfully performed in all specimens. The mean distances between portal tracts and local neurovascular structures ranged between 9.4 and 19.2 mm and there were no cases of contact. None of the tendons showed signs of iatrogenic damage. CONCLUSION: Two-millimeter-diameter operative tendoscopy provided safe and effective visualization and operative reach of the tibialis posterior, peroneal, and Achilles tendons. CLINICAL RELEVANCE: Compared with current practice, 2-mm-diameter operative tendoscopy has the potential to make tendoscopy around the ankle less invasive and more accessible. Diagnostic, interventional, and second-look procedures might be performed at substantially reduced risk, time, and costs.

Clinical results of absorbable plates for displaced metacarpal fractures.

PURPOSE: To present the clinical results of a study of unstable metacarpal fractures treated with absorbable plates. METHODS: Between July 2004 and June 2006, 12 patients (14 fractures) who presented with displaced, unstable, metacarpal fractures had open reduction and internal fixation. The overall clinical follow-up results and radiographic controls at 6, 12, and 26 weeks after surgery are reported. The clinical outcome was assessed by the Disabilities of the Arm, Shoulder, and Hand score and the visual analogue pain scale. RESULTS: The involved fingers showed an average final total active motion of 234 degrees (range, 220 degrees-265 degrees). No deformity of rotation>5 degrees was observed in any patient in the clinical follow-up evaluation. One patient had a loss of reduction with a palmar angle of the metacarpal axis of 20 degrees in the sagittal plane. A second patient with secondary loss of reduction required surgical revision, at which time internal fixation was performed by using a titanium plate. Complications included keloid formation and prolonged soft-tissue swelling for more than 6 weeks in 3 patients. No wound margin necrosis, infection, pseudarthrosis, sinus formation, or osteolysis was observed. Bone consolidation was achieved reliably within 6 weeks both clinically and radiologically. The Disabilities of the Arm, Shoulder, and Hand score results 6 weeks after surgery were an average of 30 points compared with 13 after 12 weeks and 3 points after 26 weeks. The visual pain scale showed mean values of 18 after 6 weeks, 2 after 12 weeks, and 0.2 after 26 weeks. CONCLUSIONS: Absorbable plates are suitable for use in hand surgery and allow early range of motion in combination with an additional orthosis of the hand (as described) for 3 weeks. In the early and medium-term postoperative course, no osteolysis or sterile sinus formation was observed. Metal plates are still the gold standard; however, surgical implants made of amorphous copolymer of L-lactide and glycolic acid in combination with an orthosis constitute a useful and reliable means of metacarpal fracture treatment. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.