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Display Technologies
Published in Terry M. Peters, Cristian A. Linte, Ziv Yaniv, Jacqueline Williams, Mixed and Augmented Reality in Medicine, 2018
In 1995, Edwards et al. [9] presented their augmented stereoscopic operating microscope for neurosurgical interventions. It allowed for multicolor representation of segmented 3D imaging data as wire frame surface models or labeled 3D points. The interactive update rate of 1–2 Hz was limited by the infrared tracking system. The accuracy of 2–5 mm is in the same range as the system introduced by Friets et al. [8]. In 2000, the group reported on an enhanced version [10] with submillimeter accuracy, which was evaluated in phantom studies, as well as clinical studies for maxillo-facial surgery. The new version also allowed for calibration of different focal lengths to support variable zoom level settings during the augmentation. For ophthalmology, Berger and Shin [11] suggest augmenting angiographic images into a biomicroscope. The system used image-based tracking but no external tracking, which is possible because the retina offers a relatively flat surface that is textured with visible blood vessel structures.
Ion-implanted silicon nanowires
Published in Klaus D. Sattler, Silicon Nanomaterials Sourcebook, 2017
Bennett E. Smith, Peter J. Pauzauskie
Additionally, membranes based on porous silicon have been demonstrated to be biocompatible and applied to support human ocular cells in vitro and in vivo within the rat eye [43]. A colorimetric assay for silicic acid showed that membranes with pore sizes of 40–60 nm slowly dissolved, but the material could be maintained in a tissue culture medium in vitro for at least two weeks without visible degradation. When implanted under the rat conjunctiva, the material did not erode the underlying or overlying tissue. The implant underwent slow dissolution, but remained visible at the operating microscope for over eight weeks. End-stage histology indicated the presence of a thin fibrous capsule surrounding the implant, but little evidence of any local accumulation of acute inflammatory cells or vascularization. Human lens epithelial cells and primary human corneal explants adhered to the porous silicon membranes, where they remained viable and underwent division. Primary corneal epithelial cells supported on membranes were labeled with a cell tracker dye and implanted under the rat conjunctiva. Seven days later, labeled cells had moved from the membrane into the ocular tissue spaces. A porous silicon membrane may have value as a biomaterial that can support the delivery of cells to the ocular surface and improve existing therapeutic options in patients with corneal epithelial stem cell dysfunction, and ocular surface disease [43].
Visible Light Optical Imaging and Spectroscopy during Neurosurgery
Published in Yu Chen, Babak Kateb, Neurophotonics and Brain Mapping, 2017
Sameer Allahabadi, Caroline Jia, Neal Prakash
OIS offers several potential advantages over the current gold standard for intraoperative mapping, ESM. The spatial resolution of iOIS is much greater than that of ESM. Resection within 1 cm of essential areas identified by ESM increases the likelihood of postoperative deficits (Haglund et al., 1992), suggesting the limit of resolution of ESM is on the order of 1 cm. This limited resolution does not ensure resection of as much pathological tissue as possible. iOIS, on the other hand, can potentially provide a more detailed functional map of the exposed cortex, with consequently more precise resections. The iOIS setup requires no modification of the traditional operating room configuration and does not require any major modification to neurosurgical techniques, as has been necessary for the implementation of iMRI. Furthermore, the camera used for optical imaging and spectroscopy can be mounted atop a second operating microscope so that it can be moved into and out of the sterile operating field as needed, minimizing surgical interference. iOIS is also advantageous because it is not in contact with the brain during surgery. Since iOIS only detects changes in light reflectance, it does not require any contact with potentially normal tissue that the surgeon may not want to disturb. Moreover, OIS equipment is affordable since it only requires four major components: camera, light source, computer, and a spectroscopic filter. iOIS dramatically improves a neurosurgeon’s eyesight by creating functional and lesion maps from images from the surgical microscope.
The application of indocyanine green (ICG) and near-infrared (NIR) fluorescence imaging for assessment of the lymphatic system in reconstructive lymphaticovenular anastomosis surgery
Published in Expert Review of Medical Devices, 2021
Albert H. Chao, Steven A. Schulz, Stephen P. Povoski
Lymphaticovenular anastomosis surgery is typically performed under general anesthesia, although some clinicians have also reported performing LVA under intravenous sedation. Intraoperatively, ICG lymphangiography is performed at the start of the procedure in similar fashion to what was described earlier for preoperative evaluation. The locations of subcutaneous lymphatic vessels targeted for lymphaticovenular anastomosis are then denoted on the skin with a marker. This localization is necessary in order to design surgical incisions that can be used to access subcutaneous lymphatic vessels and subcutaneous veins, as there is no anatomic regularity or predictability to the presence of location of lymphatic channels that are suitable for LVA in patients with lymphedema, and it is not possible to make this determination by physical examination. Surgical incisions are designed generally over the proximal 3–4 cm of each target subcutaneous lymphatic vessel. Isosulfan blue is also often injected distal to each planned incision and aids microsurgeons in identifying subcutaneous lymphatic vessels intraoperatively. Lymphaticovenular anastomosis surgery is then performed using supermicrosurgery, which is the technique of microanastomosis in structures that have a diameter of less than 0.8 mm. The operation is thus performed under magnification with use of an operative microscope and supermicrosurgical instruments. The previously designed incisions are made, and dissection in the superficial subcutaneous tissues are performed to identify subcutaneous lymphatic vessels and subcutaneous veins. Once identified, handsewn lymphaticovenular anastomoses are created.
Devices for minimally-invasive microdiscectomy: current status and future prospects
Published in Expert Review of Medical Devices, 2020
The current gold standard surgical technique for lumbar disc herniation (LDH) is open lumbar microdiscectomy. Its operating microscope provides precise and enlarged three-dimensional surgical visualization. Therefore, its surgical outcomes in terms of success rate and complication rate have been superior to those of the conventional open discectomy [1–5]. However, considerable skin incision and muscle retraction may cause postoperative back pain and muscle atrophy, which may delay recovery to ordinary life.