Introduction
The surgical treatment of adolescent idiopathic scoliosis (AIS) has seen several new operative strategies within the past decade, including regular usage of pedicle screws, new techniques to reduce the curve, the use of bone substitutes, blood conservation techniques, and spinal cord monitoring [
1]. These options have added complexity in surgical decision making. It is likely that these changes and perceived improvements are responsible for the variations in operative care for AIS patients [
2,
3]. Aubin et al. [
4] reported large variability in AIS instrumentation strategy and planning among a small group of experienced spine surgeons assessing the same patient. Similarly, among a group of Canadian spine surgeons surgically treating AIS, several controversies were found [
5].
Although epidemiological research has revealed that AIS is a well-defined condition which occurs globally, for many aspects of treatment, there is little evidence to draw upon and most treatment recommendations are based on case studies. Randomized control trials (RCTs) are challenging to perform in AIS patients due to the ethical concerns of applying experimental interventions in a pediatric population. In addition, with few patients treated per center and numerous variables, these trials are logistically challenging. Consequently, high-quality evidence is difficult to establish. In light of this issue, the AOSpine Knowledge Forum Deformity (AOSKF Deformity) conducted a worldwide study investigating surgeons’ contemporary perceptions of optimal operative care in AIS patients. The purpose was to survey an international group of highly experienced surgeons treating ‘routine’ AIS patients between 12 and 20 years of age with scoliotic curves ranging from 40° to 90° Cobb angle to determine what constitutes optimal operative care for the patient.
Materials and methods
Design
A modified Delphi survey was performed. This flexible survey technique is used to collect information for establishing consensus and/or forecasting future events [
6,
7]. It involves the participation of expert individuals known as panelists. Through an iterative and anonymous process, panelists provide individual knowledge and opinions which are synthesized, discussed, and summarized until a high level of agreement is reached.
For the areas of consensus, review of the literature was performed using the Pubmed database until March 28, 2014. The search queries were limited to the AIS patient population, the English-language, and topic-specific keywords. Animal studies, meeting abstracts, editorials, single case reports, and review articles were excluded. Studies identified during the searches were supplemented with literature known to the authors. Only supporting empirical evidence is described.
Panelists
Surgeons were invited to participate by an e-mail which was sent to all AOSpine members (
n = 5,608). To participate, panelists needed to personally manage a minimum of 25 surgical AIS patients per year; have practiced for a minimum of 5 years; be fluent in English; and complete three questionnaires within the study period. Ninety-two surgeons responded, 55 met the criteria, and 41 accepted the study terms and agreed to take part. In addition, seven qualified members from the AOSKF Deformity steering committee joined the panel, totalling 48 panelists from 29 countries, representing all world regions (Table
1;
Online Resource 1). Panelists were predominately male, aged 50–59, and over 80 % had been practicing for 10 or more years. The mean percentage of practice focus on pediatric spine was 50 %. To maintain objectivity, the principle investigators (MDK, MI) and project leaders (NMG, SJK, MVT) who designed and developed the surveys and pilot tester/moderator (CS) did not participate as panelists.
Table 1
Demographic profile of Delphi panelists
Gender |
Female | 1 (2) | 0 (0) |
Male | 47 (98) | 22 (100) |
Age (years) |
30–39 | 5 (10) | 1 (5) |
40–49 | 18 (38) | 11 (50) |
50–59 | 20 (42) | 7 (32) |
60–69 | 5 (10) | 3 (14) |
Region |
Asia Pacific | 12 (25) | 4 (18) |
Europe | 18 (38) | 8 (36) |
Latin America | 6 (13) | 3 (14) |
Middle East | 6 (13) | 2 (9) |
North America | 6 (13) | 5 (23) |
Years in practice |
<10 | 8 (17) | 3 (14) |
10–19 | 18 (38) | 7 (32) |
20–29 | 16 (33) | 9 (41) |
30–39 | 5 (10) | 2 (9) |
40–49 | 1 (2) | 1 (5) |
Delphi rounds
The study consisted of four rounds: three rounds used a web-based survey tool (Survey Monkey,
http://www.surveymonkey.com/) over 5 months (July–November 2012) and the final round was a face-to-face meeting (April 2013). Panelists were given 3 weeks to complete each questionnaire and ~6 weeks were allocated for analysis and questionnaire development. After each round, panelists received de-identified summaries of all responses.
The objective of Round 1 was to identify the key features involved in the surgical treatment of AIS. Panelists were asked to answer each question in terms of the procedures routinely used at their institution. This round consisted of 36 questions, including open-ended questions and requests for explanations and general feedback. These results were used to generate and refine questions for Round 2.
In Round 2, the objective was to elicit opinions about what constitutes ‘optimal’ care. Panelists were asked to answer each question based on what is optimal, not necessarily what is routinely used or feasible in their clinic (e.g., panelists may not routinely use spinal cord monitoring because of lack of facilities, but may consider it part of optimal care). There were 47 primary questions and 17 additional questions appeared through branching logic.
In Round 3, the objective remained consistent with Round 2 and included six questions. This round was performed in an attempt to reach consensus on items which required additional clarification by asking more structured questions and limiting response options.
In Round 4, 12 topics where consensus was not found were further discussed in a face-to-face meeting. Topic selection was based on previous questionnaire responses, their clinical importance, and the likelihood of reaching consensus with ‘live’ discussion. Twenty-five of 48 panelists were selected to attend the meeting based on geographic spread, years of experience, and age distribution. Through a moderated discussion, participants developed 23 questions relating to the 12 pre-selected topics. An electronic audience response system (PowerComARS, Jiangsu, China) allowed anonymous voting on each question.
Analysis
Consensus was defined a priori as ≥70 % agreement among panelists [
6,
8]. When consensus was not reached on a question, it was included in the next round if clarification of the wording or refinement of response options could reasonably facilitate consensus. The frequency of each response was determined and converted to percentages. For ranking questions, mean ranks (a value of 1 was most important) were calculated and the top two items retained. Final conclusions for each question were classified as: routinely used (consensus that the practice is routinely performed), not routinely used (consensus that the practice is not routinely performed), optimal (consensus that the practice constitutes optimal care), not optimal (consensus that not performing the practice constitutes optimal care), and no consensus (no consensus whether performing the practice constitutes routine use or optimal care). For the purposes of readability, percentages appear in the text only where consensus was achieved.
Discussion
AIS is well defined from a diagnostic point of view, yet its surgical treatment methods are varied with little high-level evidence to guide treatment. Using the Delphi method, we gained consensus from an international group of surgeons on many clinically important aspects of what is currently considered optimal surgical care for AIS patients and pinpoint areas for further research.
Through panelist feedback, we identified a subgroup of patients with large, rigid curves for whom optimal care seemed to differ from the main patient group. For these patients, there was consensus to perform routine Ponte osteotomies, but there was no consensus on preoperative traction (any form), preoperative assessment of curve flexibility to be performed with traction radiographs, and the use of higher implant density.
This study highlighted areas of no consensus. We interpret a lack of consensus on some questions to mean they may require further research, while others may not have substantial clinical consequences. For example, there was consensus on the need for intraoperative spinal cord monitoring, but no consensus on which type (SSEP or MEP). This could be left at the discretion of the surgeon and institution. Similarly, there was consensus that the use of local bone (not including iliac crest) plus one supplement as a graft material was optimal. There was no consensus or supporting empirical evidence indicating which graft material should be used.
While there is empirical evidence to support some of our findings, the AIS literature base is weak, consists almost entirely of cohorts of patients, mostly treated 10–20 years ago in well-known spine centers across the world, predominantly from the USA. Other findings diverge or remain unsupported by published empirical evidence. In addition, evidence is often conflicting, difficult to interpret due to confounding variables, and not always centered on the most clinical relevant outcome. For example, we noted a strong preference for the posterior approach, while 5–10 years ago there were multiple reports of anterior approaches including anterior video-assisted (thoracoscopic) releases and instrumentations [
58]. These approaches are now no longer considered optimal for routine care, except perhaps for lumbar Lenke 5 curves. This raises an interesting question whether some of these techniques were “fashions and hypes”, or innovations that have been superseded by newer, better posterior techniques. Conversely, current concepts of optimal care will also change over time. Of course, under certain circumstances, treatment options not considered optimal for patients with a “routine 40°–90° curve” may still be required for the individual patient.
We defined optimal care as the set of services that provide the greatest possible improvement to the health of the patient. It is patient centered and differs from maximum care. For example, every diagnostic or therapeutic procedure may have undesired effects. Therefore, performing a preoperative full spine MRI or pulmonary function test in every patient may be considered maximum care, but there was no consensus whether they were optimal by this panel. While we believe the findings of this study will result in the best possible outcome for the “routine” AIS patient (“optimal care”), this may not always be feasible depending on available health care resources and funding. Those responsible for health care provision, however, must continuously strive for ‘appropriate treatment’; high-quality services in an appropriate setting that will improve the health of the patient in the most cost-effective manner for society (appropriate care is society centered). This also does not necessarily correspond to maximal treatment. For instance, this international panel sees no need for maximum care in the areas of implant density for 40°–70° curves, use of intraoperative pedicle screw navigation, and routine postoperative CT. These findings provide possible saving of unnecessary costs, thus, in-line with appropriate care. Interestingly, both the expert opinion and published empirical evidence support an implant density below 80 % (and possibly lower) for routine care scenarios, but more research is warranted.
The strength of this study was that the design enabled the generation of up-to-date information from 48 surgeons from 29 countries worldwide. The panelists were well distributed in age and experience. All rounds were performed anonymously which eliminated the possibility of panelists being influenced or pressured by their peers. Consequently, we believe it unlikely that the findings would differ substantially if given to another panel of similar composition, and these findings are less likely to reflect treatment regimes based on tradition, familiarity, or bias (e.g., industry), but instead reflect contemporary perceptions of optimal care. The expert opinion-based findings for the consensus items were well supported by published empirical evidence, including studies published after the levels of consensus were established. Lastly, a near perfect response rate was achieved for all rounds which emphasizes the perceived need and dedication of the panelists in defining optimal surgical management for AIS.
A limitation, as with any Delphi method, was that the findings are based on expert opinion and on the assumption that if several people with diverse backgrounds agree on an issue (through anonymous voting), there is less chance of arriving at an incorrect response [
6]. Even though we employed 48 panelists worldwide, we may not have represented all caregivers.
In conclusion, multiple areas of international consensus for the current optimal surgical management for AIS were identified and supported by empirical evidence. The areas of no consensus require further research. Although many of these results are based on expert opinion and may need to be validated through quantitative research, they provide a basis for formulating current optimal surgical management recommendations. We encourage health care providers to standardize care for AIS patients and to use these findings to define appropriate care in their region. These findings should not limit future innovations. As patient care evolves, it may be necessary to diverge from what we have described as optimal care, but then future research should be performed in a controlled environment, and patient outcomes should be closely monitored and prospectively documented in a registry.