Читать книгу Surgery of Exotic Animals - Группа авторов - Страница 75

Whether the operating microscope or surgical loupe represents the optimal magnification aid for a particular type of surgery is often debated. To date, the choice seems to be one of surgeon preference, as study findings conflict and both pieces of equipment have advantages and disadvantages (McManamny 1983; Ross et al. 2003: Eivazi et al. 2015; Al‐Benna 2011; Stanbury and Elfar 2011). The operating microscope offers greater magnification than surgical loupes, is considered the gold standard in microsurgery, and is a superior teaching tool (McManamny 1983; Pieptu and Luchian 2003; Al‐Benna 2011). However, loupe magnification has been found to achieve comparable clinical outcomes, and in some studies, resulted in shorter operative times (Ross et al. 2003; Jarrett 2004; Al‐Benna 2011). Some propose of the operating microscope always be chosen by less‐experienced microsurgeons and when operating tubular structures less than 3–4 mm in diameter (Pieptu and Luchian 2003; Ross et al. 2003; Jarrett 2004; Al‐Benna 2011; Stanbury and Elfar 2011). Others suggest that so‐called “macro‐microsurgical procedures,” those involving structures >1.5 mm in diameter, may be safely performed with loupes (Pieptu and Luchian 2003; Mungadi 2010; Stanbury and Elfar 2011). Although the operating microscope can be moved through six degrees of freedom, loupes offer the convenience of being able to change field of view simply by turning one's head (Ross et al. 2003; Stanbury and Elfar 2011; Eivazi et al. 2015). The operating microscope offers the advantage of being able to change level of magnification from low to high and high to low, a maneuver often necessary when passing the needle and tying sutures (Eivazi et al. 2015). While surgical loupes allow the surgeon and assistant surgeon to view the surgery from individual and rapidly dynamic vantage points, the operating microscope requires the surgeon and assistant to view the surgery from relatively fixed positions (Ross et al. 2003; Jarrett 2004). Whereas the operating microscope should be moved only short distances and with great caution to avoid damaging the intricate lenses and prisms within, loupes offer the advantage of portability (Jarrett 2004; Hart and Hall 2007; Stanbury and Elfar 2011). Some of the mobility issues associated with the operating microscope can be overcome by using a foot pedal programmed to permit movement of the scope in the x–y planes and by changing level of magnification and focus. Operating microscopes may offer superior illumination from halogen and xenon light sources, but the addition of LED coaxial headlamps to surgical loupes has greatly improved loupe illumination capabilities (Pieptu and Luchian 2003). Although the use of loupes has been reported to result in operator fatigue, discomfort, and limited fields of view due to inappropriate working distance, poor optics, and diminished depth of focus, technological advances in loupe magnification and use of carefully obtained measurements to guide customization of loupes have diminished the impact of these limitations (Ross et al. 2003; Jarrett 2004; Hart and Hall 2007; Chang 2014b). Loupes are also significantly less expensive than operating microscopes (Pieptu and Luchian 2003; Jarrett 2004; Stanbury and Elfar 2011).