Evidence-based Surgery for Rhinosinusitis
Summary
Despite the lack of level 1 evidence from meta-analysis of randomized, controlled trials, there is a significant amount of well-designed level 2–3 evidence collected from tens of thousands of patients that endoscopic sinus surgery (ESS) is safe and is associated with improvements in symptom scores (especially nasal obstruction and discharge), disease-specific and generic quality of life ratings, and objective measures. There is also enough evidence to suggest that functional ESS is superior to conventional procedures, including polypectomy, Caldwell-Luc surgery, inferior meatal antrostomy, and antral irrigations, but superiority to conventional sphenoethmoidectomy has not yet been proven. The extent of surgery is frequently tailored to the extent of disease. In primary paranasal sinus surgery, surgical conservatism is recommended. The decision to preserve or resect the middle turbinate can be left to the discretion of the surgeon based on its disease status. There are not enough data to support the use of balloon catheters as an alternative to standard ESS techniques. Adverse predictive factors for the success of functional ESS include the presence of acetylsalicylic acid (ASA) intolerance, cystic fibrosis (CF), extensive disease, previous surgery, biofilms, osteitis, and immunodeficiency. Ten to 20% of operated patients respond poorly to sinus surgery with concomitant medical therapy and eventually require a secondary surgical procedure.
Introduction
Surgery is an imprecise art, and surgeons have traditionally had to make decisions with limited facts. Existing surgical dogma, personal experience, recommendations of surgical authorities, and thoughtful application of basic surgical skills have all assisted surgeons in that role. However, a look at the past will reveal a surgical landscape littered with procedures and interventions that have now been abandoned and are deemed useless or even harmful. Evidence-based surgery aims to improve doctors’ decision-making process by helping them to critically assess the available literature and incorporate findings into everyday practice. It also emphasizes the need to evaluate adequately the efficacy of surgical interventions before accepting them as standard. In that effect the Oxford Center for Evidence-based Medicine produced in 2011 a new simplified classification of levels of evidence ( Table 18.1 ). Essential for evidence-based surgery is a clear definition of the disease and standardized outcome measures.
Evidence-based surgery does not always have to rely on randomized, controlled trials. In surgery, such trials are often neither ethical nor feasible; however, the fact remains that we need to evaluate the available evidence to prevent us from giving our patients ineffective or even harmful treatments ( Table 18.2 ).1 Evaluation of the available evidence is not always easy. There are several potential biases in all types of medical research (expectancy bias/patients’ expectations from treatment, variations between patients/selection bias, co-intervention and timing bias, publication bias, and withdrawal bias). Surgical studies introduce additional types of bias, including the lack of patient blinding to the surgical intervention and performance bias (procedures or interventions are not executed in a uniform way—any one surgeon may do the same procedure in a different way from day to day, and that is even more true among surgeons). Despite these difficulties, studies are being performed, and sinus surgeons should critically evaluate published evidence and adjust their practices accordingly.
Measuring the Efficacy of Sinus Surgery
Patient-reported Outcome Measures
The most obvious way of assessing the efficacy of sinus surgery is by measuring patients’ symptoms. This can be achieved by evaluating individual symptoms, such as nasal obstruction, rhinorrhea, loss of smell, and facial pain, or using disease-specific or generic quality of life patient-reported outcome measures (PROMs).
The degree or severity of symptoms can be assessed using many different grading tools. It can be graded in a Likert-type scale as severe, moderate, mild, or asymptomatic or as a visual analogue scale (VAS) score giving a measurable continuum (e.g., 0–10 cm). However, two dimensions must always be taken into account: duration as well as severity. A recent study considered the relationship between subjective assessment instruments in chronic rhinosinusitis (CRS) and showed that mild equates to a VAS score ≤ 3, moderate to > 3–7, and severe to > 7–10 ( Fig. 18.1 ).2 Various symptom scores have been used to show the efficacy of sinus surgery in nasal polyposis.
Typically, quality of life studies have focused on assessment of generic quality of life. Generic health-related quality of life (HRQOL) questionnaires, such as Short Form Health Survey 36 (SF-36), allow comparison between patients with different diseases and hence can inform policy decisions.3 However, generic instruments may be unresponsive to small (but to the patient important) changes in HRQOL. Piccirillo et al4 were the first to publish a disease-specific HRQOL instrument for rhinosinusitis (Rhinosinusitis Outcome Measure 31, RSOM-31). In recent years, many other HRQOL questionnaires have been developed specifically for rhinosinusitis (see Chapter 9 for more information); however, SNOT-22 and RSOM31 are the tools currently recommended for adult CRS.2
Clinician-reported Outcome Measures
Although less relevant from a patient′s point of view, clinician-rated outcome measures are less prone to bias, including expectancy bias. The drawback of clinician-recorded measures is that they often correlate poorly with patients’ complaints.5 Common “objective” outcome measures include radiologic measures (e.g., Lund-McKay radiologic score), endoscopic measures (e.g., polyp grading, Table 18.3 ), functional measures (peak nasal inspiratory flow [PNIF], acoustic rhinometry, nitric oxide, and saccharine clearance time), and (semiobjective) the need for revision surgery. Their use can improve our understanding of the efficacy of an intervention, but they should be interpreted in conjunction with changes in PROMs.
Functional Endoscopic Sinus Surgery in Acute Recurrent Rhinosinusitis
There is a paucity of evidence of the role of surgery in acute recurrent rhinosinusitis. One prospective noncomparative study that used stringent criteria for recurrent acute rhinosinusitis showed 2.5 fewer acute episodes and 2 fewer days off work as well as symptomatic improvement in 19 patients after 19 months of follow-up.6 A recent prospective, nested case control study compared 22 patients with acute recurrent rhinosinusitis with 22 matched patients with CRS without nasal polyps using the Rhinosinusitis Disability Index (RSDI) and Chronic Sinusitis Survey (CSS). Both groups had significant improvements in quality of life, with the recurrent acute rhinosinusitis group demonstrating reduced use of medication after surgery7 (level 3).
Basis for clinical decisions | Marker |
Evidence | Randomized, controlled trial |
Eminence | Radiance of white hair |
Vehemence | Level of stridency |
Eloquence (or elegance) | Smoothness of tongue or nap of suit |
Providence | Level of religious fervor |
Diffidence | Level of gloom |
Nervousness | Litigation phobia level |
Confidence* | Bravado |
* Applies only to surgeons. | |
From Isaacs D, Fitzgerald D. Seven alternatives to evidence based medicine. BMJ 1999;319:1618. | |
Functional Endoscopic Sinus Surgery in Chronic Rhinosinusitis with and without Nasal Polyps
Randomized, Controlled Trials
The gold standard of evidence-based surgery is the randomized, controlled trial. However, the search for such studies is not always successful; meanwhile, surgeons have to practice with the best available evidence. The Cochrane collaborative reassessed and revised in 2009 the evidence for surgery in CRS.8 They screened 2323 studies and found 6 randomized, controlled trials. Using strict methodological inclusion criteria, they excluded three of these studies and examined the three remaining ones. The first, a University of London thesis written by Fairley in 1993,9 compared 12 patients undergoing endoscopic middle meatal antrostomy with 17 patients who underwent conventional intranasal inferior meatal antrostomy. The study found symptom improvement in both groups but no differences between groups; 1- year follow-up data were available for 11 patients and 9 patients, respectively, a sample size the author acknowledged as being too small to exclude a type II error. The second study from 199710 assessed patients with isolated maxillary sinusitis and compared symptom improvement after ESS and after saline rinses among patients randomized before antibiotics were administered. The third study by Ragab et al from 200411 was the most relevant of the three, as it randomized 90 patients in medical (long-term antibiotics) or surgical (ESS) management and assessed both objective (endoscopic scores, nitric oxide, PNIF, and saccharine clearance time) and patient-reported outcomes (symptoms VAS, SF-36, and Sino-Nasal Outcome Test 20 [SNOT-20] scores). It found that both treatments significantly improved almost all the subjective and objective parameters of CRS (P < .01), with no significant difference being found between the medical and surgical groups, except for the total nasal volume, in which the surgical treatment demonstrated greater changes. However, the surgical group received only 2 weeks of erythromycin after surgery, whereas the medical group received 3 months of erythromycin after randomization. There was no placebo group, which somewhat reduces the importance of these findings.
The Cochrane collaborative, using data from these 212 patients, stated that ESS “has not been demonstrated to confer additional benefit to that obtained by medical treatment with or without antral irrigation in relieving the symptoms of chronic rhinosinusitis.”8 However, our impression is that there was simply insufficient evidence for any comment about the value of ESS compared with medical treatment based on these three studies. The first study included in the Cochrane review9 did not compare ESS with medical treatment, and the other two studies10,11 did not analyze ESS results among patients who failed medical treatment, including antibiotic therapy. Indeed, current thinking states that sinus surgery must always be preceded and/or followed by various forms of medical treatment, including nasal douching, nasal steroids, systemic steroids, and systemic antibiotics. The European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS) guidelines advise always trying medical treatment before considering surgery.2 The medical treatment depends on the severity of symptoms, from nasal spray in cases of mild nasal polyps to a combination of systemic corticosteroids and local corticosteroid treatment in patients with severe disease.11–14
Two other randomized, controlled trials have been published but have not been included in the Cochrane review, as they refer to patients with CRS with nasal polyps (CRSwNP). The two studies by Lildholdt et al in 199713 and 198815,16 compared single injections of 14 mg betamethasone with intranasal polypectomy 12 months after treatment with intranasal steroids. There was no difference in mean nasal score or sense of smell between the two groups. Since the last update of the Cochrane review, a new randomized, controlled trial on CRSwNP was published,17 albeit in the same group of patients described earlier,12 focusing exclusively on CRSwNP. In the earlier study, symptom scores improved significantly with medical treatment alone; surgery had additional beneficial effects on nasal obstruction and secretion but not on olfaction. The recent study showed a surgery- related improvement in computed tomography (CT) Lund-McKay scores but not in symptom scores, as compared with medical treatment ( Table 18.4 ).
Case Series, Case Control, and Cohort Studies
Randomized, controlled trials in surgery are notoriously difficult to organize and as in the case of truly blind “sham” studies, potentially unethical. If these are not available, it is appropriate to assess the available evidence, even if it is level 3 or 4 (indeed, it is clear in the new classification of levels of evidence [ Table 18.1 ] that a level may be graded up if there is a large or very large effect size of treatment). It seems counterintuitive to ignore high- quality evidence collected from thousands of patients purely on the grounds that it is not a randomized, controlled trial.
In a review first published in 200318 and updated in 2006,19 Dalziel et al. screened 632 articles and evaluated 42 articles published between 1978 and 2005 on the effect of functional ESS on CRSwNP. A total of 12,329 patients were enrolled in the included studies. Major reasons for exclusion were the narrative character of the publication and a candidate pool of fewer than 50 patients. The authors reviewed 3 randomized, controlled trials comparing functional ESS with Caldwell-Luc or conventional endonasal procedures (n = 240), 4 nonrandomized studies comparing different surgical modalities (n = 2971), and 35 case series (n = 9118). Consistently, patients judged their symptom “improved” or “greatly improved” in 75 to 95% (level 4). The percentage of overall complications was 1.4% for functional ESS compared with 0.8% for conventional procedures.
In 2000 the Clinical Effectiveness Unit of the Royal College of Surgeons of England conducted the National Comparative Audit of Surgery for Nasal Polyposis and Chronic Rhinosinusitis, covering the work of 298 consultants working in 87 hospital sites in England and Wales.20 Patients undergoing sinus surgery were prospectively enrolled and followed up in this observational study at 3, 12, and 36 months postoperatively using SNOT-22 as the main outcome measure. Two-thirds (2176) of the 3128 patients participating in this study had CRSwNP. Patients with CRSwNP more frequently suffered from concomitant asthma and ASA intolerance and had more previous sinonasal surgery; also, their mean CT score was higher, and their mean SNOT-22 symptom score was slightly lower than that of patients with CRS without polyps (CRSsNP). All forms of sinus surgery were included, although the majority of procedures were performed endoscopically. Overall there was a high level of satisfaction with the surgery, and clinically significant improvement in the SNOT-22 scores was demonstrated at 3, 12, and 36 months.20 Patients with nasal polyps benefited more from surgery than the patients with CRSsNP. Revision surgery was indicated in 3.6% at 12 months and 11.8% at 36 months. Major complications were rare. Five-year follow-up results from almost half of the patients of this audit were published in 2009;21 19% of patients surveyed underwent revision surgery during these 5 years, including 21% of patients with nasal polyps compared with 15% of patients with CRS alone. The mean SNOT-22 score for all patients was 28.2, very similar to the results observed at 36 months (27.7), and represents a consistent 14-point improvement over the baseline score. Scores were better for patients with polyps (mean 26.2) than patients with CRS alone (mean 33.3) (level 3) ( Fig. 18.2 ).
Similar results were shown in a recent case series study of patients with CRS with particularly extensive polyposis.22 Of the 118 patients reviewed, 59 (50%) had asthma, and 93 (79%) had documented allergy. All patients received extensive bilateral nasal polypectomy, complete anterior and posterior ethmoidectomy, and maxillary sinusotomy. One hundred (85%) also had frontal or sphenoid sinusotomy. Follow-up ranged from 12 to 168 (median 40) months. Despite pre- and postoperative nasal and systemic steroid treatment in the majority of patients, 71 (60%) developed recurrent polyposis, 55 (47%) were advised to undergo revision surgery, and 32 (27%) underwent revision surgery.
Note
Although ESS has been shown to be effective in patients with CRS with nasal polyps, the surgeon should always inform the patient of the potential need for revision surgery.
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