Surgery may be performed for various reasons. A surgical pro-cedure may be diagnostic (eg, biopsy or exploratory laparo-tomy). It may be curative (eg, excision of a tumor or an inflamed appendix) or reparative (eg, multiple wound repair). Surgery may be reconstructive or cosmetic (eg, mammoplasty or a facelift), or it may be palliative (eg, to relieve pain or correct a problem; for instance, a gastrostomy tube may be inserted to compensate for the inability to swallow food). Surgery may also be classified according to the degree of urgency involved: emergent, urgent, required, elective, and optional. These terms are defined in Table 18-1.