***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Chronic rhinosinusitis affects millions of North Americans and has been increasing annually since 1991 . This study aim ed to evaluate the effectiveness of functional endoscopic sinus surgery ( FESS ) done with the use of computer assistance ( CASS ) and without the use of computer assistance on patient quality of life . As of this writing , there is no published study that measures the difference in patient quality of life with and without image guidance in endoscopic sinus surgery . METHODS A nonr and omized prospect i ve study was performed on 95 patients . A 31-item quality of life ( Rhinosinusitis Outcome Measures Form [ RSOM-31 ] ) question naire was administered to patients prior to surgery and 6 months following surgery during a 3-year enrollment period . Patients assessed both rhinologic and nonrhinologic symptoms using a statistically vali date d scoring system . Statistical analysis was performed using both equal and unequal variance sample t-tests when appropriate . RESULTS Statistically significant improvement in mean score analysis between preoperative and postoperative results for all symptom subgroups was reported when the entire study population was included . When the improvement in quality of life was compared between the CASS and FESS surgical groups , the CASS group demonstrated an overall greater improvement in quality of life . CONCLUSION Quality of life restrictions in patients with chronic rhinosinusitis were greatest in the areas of nasal symptoms and sleep deprivation , which were significantly improved by endoscopic sinus surgery . Although the long-term effect of CASS as measured by patient quality of life remains relatively unknown , there appears to be a significant trend indicating greater quality of life improvement in the short- term over non-computer-assisted FESS techniques Evidence -based clinical practice guidelines can reduce the delivery of inappropriate care and support the introduction of new knowledge into clinical practice ( 1 - 3 ) . In many cases , guidelines encapsulate the most current knowledge about best practice s. Rigorously developed guidelines can translate complicated research findings into actionable recommendations for clinical care ( 4 ) . Over the past decade , a plethora of guidelines has been created and published by a multitude of organizations at substantial cost . Despite the enormous energies invested in guideline authoring , the quality of individual guidelines varies considerably . In its l and mark report , the Institute of Medicine ( IOM ) defined 8 desirable attributes of clinical practice guidelines : validity , reliability and reproducibility , clinical applicability , clinical flexibility , clarity , documentation , development by a multidisciplinary process , and plans for review ( 5 ) . However , critical information that would attest to validity or would document fulfillment of the other IOM criteria is regularly absent from published guidelines . In an evaluation of 279 guidelines developed by U.S. medical specialty societies , Shaneyfelt and colleagues ( 6 ) found that guidelines published in the peer- review ed medical literature do not adhere to established method ologic st and ards . Likewise , Grilli and colleagues ( 7 ) found that of 431 guidelines produced by specialty societies , 82 % did not apply explicit criteria to grade the scientific evidence that supported their recommendations , 87 % did not report whether a systematic literature search was performed , and 67 % did not describe the type of professionals involved in guideline development . Systematic review s of guidelines for drug therapy ( 8) , management of depression ( 9 ) , and osteoporosis ( 10 ) have confirmed marked variation in quality . Both nonadherence to method ologic st and ards and failure to document development activities contribute to this variation . We convened the Conference on Guideline St and ardization ( COGS ) to define a st and ard for guideline reporting that would promote guideline quality and facilitate implementation . The proposed st and ard provides a checklist of components necessary for evaluation of validity and usability . The checklist is intended to minimize the quality defects that arise from failure to include essential information and to promote development of recommendation statements that are more easily implemented . In contrast to other instruments that have been developed for post hoc evaluation of guideline quality , the COGS checklist is intended to be used prospect ively by developers to improve their product by improving documentation . The COGS panel used a systematic and rigorous process to define content of the proposed st and ard and to achieve consensus . The COGS panel also included a wide variety of perspectives , deliberately bringing together representatives from medical specialty societies , government agencies , and private groups that develop guidelines ; journal editors and the National Guideline Clearinghouse ( NGC ) , which disseminate guidelines ; guideline implementers , including managed care representatives and informaticians ; and academicians . Methods We actively sought people with diverse background s from wide-ranging geographic areas to participate in the meeting . Selection criteria for participants were 1 ) activity in a wide variety of guidelines initiatives , 2 ) recognition as leaders in their field , and 3 ) willingness to collaborate . To maximize interaction , the number of participants in the Conference was limited . We set as a task for the panelists the specification and definition of a set of necessary guideline components that should be considered for reporting in all evidence -based practice guidelines . We defined necessary items as those that establish the validity of the guideline recommendations or facilitate practical application of the recommendations . We noted that many additional items might be considered appropriate components in guidelines , but sought to define a minimal set of essential elements . We assembled a list of c and i date guideline components from the IOM Provisional Instrument for Assessing Clinical Guidelines ( 5 ) , the NGC ( 11 ) , and the Guideline Elements Model ( 12 ) , a hierarchical model of guideline content that was created from a systematic review of published guideline descriptions . These items were supplemented with items highlighted in the literature , for example , structured abstract ( 13 ) and conflict of interest ( 14 ) . We applied a modified Delphi approach to help focus group discussion . This approach has been widely applied for evaluation of expert opinion on appropriateness ( 15 ) and medical necessity ( 16 ) , for policy development ( 17 ) , and for prioritization ( 18 ) . The technique has been described in detail ( 19 ) . In brief , after we secured agreement to participate in the COGS panel , we gave all participants a bibliography of re sources regarding guideline quality and its appraisal , guideline implementation , and the modified Delphi consensus development approach . Panelists were asked to rate their agreement with the statement that [ Item name ] is a necessary component of practice guidelines on a 9-point scale . Rating an item with a 9 indicated strong agreement with the statement that this item was necessary . Rating an item with a 1 indicated strong disagreement with the statement and suggested that the item was absolutely unnecessary in a guideline . A rating of 5 indicated neutrality or indifference . We developed a password-protected Web site that panelists used to complete the first round of ratings online before the meeting . Online rating permitted accurate and efficient data capture and analysis . For each item , the median rating and the disagreement index ( defined as the Interpercentile Range divided by the Interpercentile Range Adjusted for Symmetry ) were calculated ( 19 ) . The disagreement index , which can be calculated for panels of any size , describes the dispersion of ratings more effectively than the mean absolute deviation from the median . Index values greater than 1 indicate disagreement . We displayed summary statistics for each item on a form that was individualized for each panelist . The COGS meeting was held on 26 and 27 April 2002 in New Haven , Connecticut . In a colloquy facilitated by 2 of the authors , each c and i date item was discussed to ensure that all participants agreed on its definition and potential contribution to the COGS checklist and to highlight empirical evidence of its value . When appropriate , additional items were added to the list . The group determined that in the second round of ratings , it would be valuable to rate each item 's necessity on 2 subscales : necessity to establish validity and necessity for practical application . The participants then rated each item on these 2 dimensions . Analysis We tallied the median score and the disagreement index for each item . We retained items with median scores of 7 or higher and disagreement indexes less than 1.0 on either scale as necessary guideline components on the checklist . To interpret necessity , the 9-point scale is divided into 3 ranges : items scoring 1 to 3 are considered unnecessary , items scoring 4 to 6 are neutral , and items scoring 7 to 9 are considered necessary ( 20 ) . In this study , the threshold of 7 was chosen because it represented the lowest rating at which the participants indicated that an item was necessary for inclusion in guidelines . Pilot Review To field test the proposed checklist , we surveyed organizations that were active in guideline development . We identified all organizations that met the NGC Web site criteria for guideline display on 12 July 2002 . From that list , we selected organizations that had developed 10 or more guidelines displayed on the NGC Web site . We excluded 1 ) organizations that participated in development of the COGS checklist [ because of potential bias ] and 2 ) government agencies and organizations based outside the United States ( for logistic reasons ) . A draft COGS checklist and a brief survey were sent to the people identified as being responsible for guideline development at each eligible organization . Results All 23 panelists su bmi tted first- and second-round ballots . During the discussion , participants suggested consideration of 10 new items in the second round of balloting and refined definitions of several items . Thirty-six discrete items were considered necessary to establish guideline validity ; they received ratings of 7 or greater and had disagreement indexes of less than 1 . Twenty-four items were considered necessary for practical application of the guideline , each with a disagreement index less than 1 . Several items were rated necessary on both dimensions . Overall , 44 discrete items were considered necessary . Closely related items were then consoli date d into 18 topics to create the COGS checklist for reporting clinical guidelines ( Table ) . Appendix Tables 1 and 2 present a complete listing of all items rated and their scores . Table . The COGS Checklist for Reporting Clinical Practice Guidelines Appendix Table 1 . Items Ranked Necessary for Guideline Validity , Median Ratings , Distribution of Ratings by Tertiles , and Disagreement Index Appendix Table 2 . Items Ranked Necessary for Guideline Usability , Median Ratings , Distribution of Ratings by Tertiles , and Disagreement Index Twenty-two organizations met eligibility criteria for evaluation of the draft checklist , and all completed the survey ( 100 % response rate ) . Sixteen organizations ( 73 % ) responded that they believed the checklist would be helpful for creating more comprehensive practice guidelines , and an additional 2 organizations ( 9 % ) responded that it might be helpful . Nineteen respondents ( 86 % ) indicated that documenting the proposed items would fit within their organizations ' guideline development methods . Fifteen ( 68 % ) stated that they would use the proposed checklist in guideline INTRODUCTION Computer-assisted surgery ( CAS ) has found widespread use in functional endonasal sinus surgery ( FESS ) over the past few years . The present study investigates if CAS leads to a better outcome in FESS . MATERIAL AND METHODS All patients who underwent endonasal sphenoethmoidectomy were enrolled in a prospect i ve , non-r and omized case-control study . The procedures were done without CAS ( group A ) in 2003 and with CAS ( group B ) in 2004 , using a Stryker navigation unit . Sixty-two patients ( 113 sphenoidectomies ) were included in group A and 61 patients ( 109 sphenoidectomies ) in group B. The underlying disease was recurrent chronic sinusitis or polyposis nasi in all patients except for inverted papilloma in one patient from group A and in two patients from group B. The follow-up period was 12 months . Symptom scores were assessed preoperatively and at 12 months postoperatively , using a question naire . A CT-scan was obtained in all patients preoperatively and at 6 months postoperatively . RESULTS No significant difference was found between group A and B , neither with respect to symptom scores at 12 months postoperatively , nor in postoperative CT-scans . The operation strategy did not change by the introduction of CAS . The frontal sinuses were entered in group A and B in 59 % and 64 % of the patients , respectively . All parameters improved significantly postoperatively , compared to the preoperative values . As far as complications are concerned , two anterior orbital injuries and one retrobulbar haematoma occurred in group A and one postoperative lacrimal stenosis in group B. CONCLUSIONS CAS does not lead to a better clinical outcome in FESS . Our data suggest that the rate of complications may be reduced using CAS . However , studies with a much larger number of patients would be necessary in order to definitely answer the question of whether CAS reduce complications in FESS BACKGROUND Although image-guidance systems have gained widespread acceptance for neurosurgical procedures , their role for extracranial surgery of the head and neck is yet to be defined . OBJECTIVES To describe the authors ' experience with image-guidance systems and to measure the effects of image-guided technology on the performance of minimally invasive otolaryngological procedures . DESIGN Prospect i ve cohort study . METHODS Optical- and electromagnetic-based image-guidance systems were used during the performance of  endoscopic surgery on patients with disease of the paranasal sinuses , orbit , skull base , and temporal bone ( n = 79 ) . Results were compared with those in control patients who underwent similar surgery without image guidance during the same period ( n = 42 ) . RESULTS Intraoperative anatomical localization was accurate to within 2 mm at the start of surgery in all cases . Accuracy de grade d by 0.89 + /- 0.20 mm ( mean + /- SE ) during the operative procedure . The use of an image-guidance system increased operating room time by a mean of 17.4 minutes per case ( image-guidance group , 137.3 + /- 6.0 minutes [ mean + /- SE ] ; control group , 119.9 + /- 5.7 minutes ; P=.006 ) and increased hospital charges by approximately $ 496 per case . Intraoperative blood loss ( image-guidance group , 178.4 + /- 18. 
    Output:
    
Based on the best available evidence in the literature , the use of IGS has not clearly been shown to decrease surgical complications or improve surgical outcomes .