instruction:
Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.
question:
Context: Complications after immediate breast reconstruction pose a significant challenge to the reconstructive surgeon. Known risk factors include smoking, obesity, age, and adjuvant oncologic therapies. Less is known about the association between axillary lymph node dissection (ALND) and the development of postoperative complications.', 'We conducted a retrospective study of all patients who underwent immediate breast reconstruction after mastectomy at our institution over a 10-year period. Our outcome was an occurrence of a major complication within 90 days postoperatively. For each patient, we recorded data on demographics, smoking status, pertinent medical history, reconstruction type, adjuvant chemotherapy and radiation, tumor pathology, and whether an ALND was performed. Odds ratios (OR) were calculated to estimate the risk of a complication if an ALND was performed.', 'One hundred eighty-four women, with 270 surgically treated breasts, were identified as having mastectomy with immediate reconstruction between 2002 and 2012. Mean age was 49.4 years (range, 25-84 years). There were 71 mastectomies with ALND performed, with 22 complications, and 199 mastectomies without ALND, with 20 complications (31% complication rate vs 10%, respectively; OR, 3.84; P < 0.001). When adjusted for reconstruction type, smoking history, obesity, age, presence of invasive disease, chemotherapy, and radiation therapy, the OR for complications was 3.49 (P < 0.01). The most common complication was infection in both groups.
Answer: Mastectomy with ALND is associated with a 3-fold increase in risk of major complications in women undergoing immediate breast reconstruction, even after adjustment for known risk factors and confounders. Further studies are warranted to elucidate how ALND leads to these complications and what measures can reduce their occurrence.
answer:
Does axillary Lymph Node Dissection be a Risk Factor for Major Complications After Immediate Breast Reconstruction?


question:
Context: To assessdoctor's knowledge on the relevance of the problem of sleep disorders, methods of their diagnosis and treatment.", 'The survey was conducted among90physicians of different the rapeuticspecialties of Kazan medical institutions.', 'The doctors believe that main causes of sleep disorders are stressors (20%), depression (13%), neurosis (13%), chronic diseases (13%), asthenia (10%), pain (10%). An analysis of treatment prescribed to patients with sleep disorders revealed large differences.
Answer: Physicians are not well informed about the problems of sleep disorders, have a small idea of the methods of sleepresearch and drugs for their treatment as well as of a sequence of operations that should be used to resolve this problem.
answer:
Do [ What do the doctors of different specialties know about sleep disorders and their treatment ]?


question:
Context: Magnifying endoscopy with narrow-band imaging (ME-NBI) is more reliable than chromoendoscopy (CE) for delineating the horizontal extent of early gastric cancers prior to endoscopic submucosal dissection (ESD). However, the added benefits of ME-NBI over CE in terms of the difference in magnification level have yet to be elucidated. The aim of this study was to investigate the improvement in diagnostic accuracy for tumor delineation obtained with different magnification levels of ME-NBI following CE.', 'This was a retrospective study, performed at a single tertiary referral center. A series of 158 consecutive patients with 161 early gastric cancers resected en bloc using ESD was included in the study. The margins of each lesion were examined in their entirety using CE, followed by low power optical magnifying endoscopy with narrow-band imaging (LM-NBI), and finally the highest power optical magnifying endoscopy with narrow-band imaging (HM-NBI). The primary endpoint was the added benefit, as measured using the successful delineation rate, for the delineation of gastric cancer margins using CE\u2009+\u2009LM-NBI vs CE, and for CE\u2009+\u2009LM-NBI\u2009+\u2009HM-NBI vs CE\u2009+\u2009LM-NBI.', 'The successful delineation rates (95 % CI) using CE, CE\u2009+\u2009LM-NBI and CE\u2009+\u2009LM-NBI\u2009+\u2009HM-NBI were 72.7 % (68.5-79.9 %), 88.9 % (84.2-93.8 %), and 98.1 % (95.8-100 %). The diagnostic accuracy improved significantly for CE\u2009+\u2009LM-NBI compared with CE (P\u2009<\u20090.001), and for HM-NBI compared with LM-NBI (P\u2009<\u20090.001).
Answer: HM-NBI is useful for improving diagnostic performance for endoscopic delineation of early gastric cancers, following CE and LM-NBI.
answer:

Is highest power magnification with narrow-band imaging useful for improving diagnostic performance for endoscopic delineation of early gastric cancers?