Spinal deformity is the oldest disease known to humankind (Kostuik 2015) The deformity in the adult spine may be ongoing for a long time or it may be a sequel to a developmental deformity experienced in childhood. There may also be a variety of contributing factors seen in childhood or adolescence. Thus, there may be many types of deformity involving the spinal vertebrae such as adult and adolescent forms of scoliosis, kyphosis, and lordosis (Diebo et al. 2019). Various treatment methods, including both conservative and surgical, have been applied to spinal deformities. Spinal alignment is important for maintaining an upright posture, protection of neural elements, and stability of the axial skeleton (Kim et al. 2020).

Scoliosis is defined as lateral deviation, axial rotation, and abnormal sagittal curvature of the spine, and is one of the most common spinal deformities. Hyper-kyphosis and lordosis are other types of sagittal plane spinal deformities often seen in clinical practice. All of these spinal conditions may lead to cosmetic appearance problems (Goldberg et al. 2001; Marks & Qaimkhani 2009; Weiss & Moramarco 2017), pain (Achar & Yamanaka 2020), postural imbalance (Herman et al. 1985), biomechanical deterioration (Schultz 1984) and respiratory dysfunction (Johari et al. 2016).

Many types of therapeutic approaches are being investigated but it is unclear which treatment is superior. Conservative treatment consists of exercise, which is broadly used (Negrini et al. 2003; Rigo, Reiter & Weiss 2003; Rivett et al. 2014; Weiss 2011; Weiss, Weiss & Petermann 2003), and bracing (Rivett et al. 2014; Weinstein et al. 2013). There is promising evidence regarding the efficacy of conservative treatment, especially exercise, in various spinal deformities (Anwer et al. 2015; Gür, Ayhan & Yakut 2017; Li et al. 2021; Liu et al. 2020; Park, Jeon & Park 2017; Parveen et al. 2020), and despite the growing high-quality evidence, the heterogeneity of the study protocols limits the generalisability of the recommendations (Negrini et al. 2018).

Surgery is another option; however, the long-term effects of surgery should be further considered. This option is much more invasive, with increased risk and in the long-term might be more problematic, given it does not always provide better results than conservative methods (Bettany-Saltikov et al. 2015; Romano et al. 2013). There is no evidence-based consensus on the superiority of either one of these options, namely conservative or surgery options (Acaroglu et al. 2017; Bettany-Saltikov et al. 2017; Kaspiris et al. 2011). Some evidence describes the importance and beneficial effects of different exercises (Berdishevsky et al. 2016; Negrini et al. 2015), but exercise needs a high level of patient compliance and should be performed as a disciplined routine.

Bracing is the most common conservative treatment option in spinal deformities. High quality studies exist supporting brace treatment during growth in patients with scoliosis (Weinstein et al. 2013; Weiss & Turnbull 2020b) and there is some evidence that standardised Chêneau style braces may be more sucessful than the more symmetric Boston style braces (Minsk et al. 2017; Weiss et al. 2020). Compliance with brace wearing, especially wearing the brace for sufficent time for potential benefit, is a key point (Rivett et al. 2014), because the benefit increases with longer hours of brace wearing (Weinstein et al. 2013). This may be stressful for patients who have to wear a brace for extended periods (Kuru & Yilmaz 2012). Brace support for pain and deformity might be indicated in adult patients with spinal deformities (Weiss & Turnbull 2019). Soft braces are not reported useful enough for stiff deformities (Weiss & Turnbull 2020b). There is evidence that pain can be successfully reduced with these bracing approaches, mainly affecting the sagittal profile (Weiss & Turnbull 2019). Adult patients with scoliosis can be tested explicitly for postural pain before the prescription of braces. In patients with larger deformities and those aiming to reduce their deformity, pattern-specific scoliosis braces are successful. It has been reported that there is no high-quality evidence to support brace treatment in adult patients with spinal deformities; however, the available evidence appears to be promising (Weiss & Turnbull 2020b).

Because there is a lack of validated guidelines outlining the importance and beneficial effects of conservative methods (Day et al. 2019), we decided to undertake our study to motivate clinicians to choose and understand conservative management. Guidelines are accepted as important tools in evidence-based practice that can reduce healthcare variation and improve patient outcomes (Woolf et al. 1999). Clinical practice guidelines are systematically developed statements that intend to assist clinicians and patients in making decisions about appropriate healthcare in specific circumstances (Field & Lohr 1992). To date, there is no gold standard for the treatment of spinal deformities, because there are not many studies comparing the effects of therapeutic interventions, namely surgery, bracing, and conservative methods such as exercise that includes specific exercises. It is important to have validated guidelines to create a systematic conservative treatment methodology.

There are no adequate and suitable comparable studies that help us to make a choice between exercise and surgical applications. An accurate assessment should be made considering the suitability of surgery for patients, and the risks, long-term effects, and complications that may arise. A conservative treatment guideline, which includes systematic exercise and brace therapy, may provide consistency in treatment methods and facilitate comparisons with surgery. It will be of value to be able to compare the cost-effectiveness of these treatment options and this may help clinicians to choose the right patient for the most suitable treatment. Our questionnaire aimed to validate a published guideline protocol (Weiss & Turnbull 2020a) based on the conservative treatment of these types of deformities.

To provide validated guidelines for therapists and patients, a questionnaire containing 46 questions was provided and emailed to professionals worldwide regarding the conservative treatment of spinal deformities. This questionnaire was intended to be evaluated and validated and is derived from the guideline protocol (see Appendix 1) published after a thorough evaluation by the Schroth Best Practice Experts (Weiss & Turnbull 2020a).

We aimed to test the guideline protocol by using a modified Delphi method. The Delphi method was developed in the 1950s by two researchers, Olaf Helmer and Norman Dalkey, working at RAND (an organization formed immediately after World War II to connect military planning with research and≈development decisions) (RAND Corporation, 2021) in the USA, specifically to provide predictions on military issues. This method is widely used and accepted for achieving convergence of opinion concerning real-world knowledge solicited from experts within specific topic areas (Dalkey & Helmer 1963). It is a method that systematically obtains expert opinions on the subject in the presence of a problem. Thus, using the≈Delphi method can enable individuals and groups who look at a problem or clinical situation from different angles to reconcile their opinions without coming face to face. The use of the Delphi method often includes questionnaires applied sequentially to experts on a particular topic. After each round, the results are communicated to the participants. The process continues in this manner until consensus is reached. The consensus that is then achieved is the end product of this process (Dalkey & Helmer 1963; Patton 2008).

The questionnaire based on the conservative treatment of spinal deformities, which was derived from a protocol, contained three parts, including 21 general statements, 15 statements regarding indications for scoliosis, and 10 statements regarding indications for kyphosis treatment. The participants were informed that they could decide whether they agreed with each statement or not, using a level of agreement or disagreement (measuring scale from 1 (little agreement or disagreement) to 7 (strongest agreement or disagreement). There was consensus for this Modified Delphi method, which was revealed by the fact that 80% of respondents indicated that they ‘Strongly Agree’ with the statement, which means ‘I support this recommendation very strongly’. Thus, we accepted 80% and this included levels of agreement 5, 6, and 7 as the cut-off point, which means that these statements reached consensus.

The participants included medical doctors, physiotherapists, orthotists, personal trainers and others with a special interest in spinal deformities. They were the ones working with patients with spinal deformity who had both theoretical and practical knowledge and experience in the field. All participants had at least 2 years or more experience in this field. One hundred and forty-five international participants were invited to complete the questionnaire.The number of participants in Delphi studies varies, as there is no agreement as to how many people should ideally be included in a Delphi study (Murphy et al. 1998).

Contacted individuals received an email, including written explanations about the completion of the questionnaire, two attached documents (the questionnaire was sent as a word document and as a portable document (PDF) format) and a link for online questionnaires with a 2-week deadline for completion and return. In theory, the Delphi method can be iterated continuously until consensus is reached. However, it is noted that two or three rounds are usually sufficient to gather the necessary information and, in most cases, to reach consensus (Brooks 1979; Custer, Scarcella & Stewart 1999; Fernández-Llamazares et al. 2013).

We implemented a two-round modified Delphi method. The participants were informed that the data derived from the answered questionnaires was anonymous. Quality assurance was ensured by two academic physiotherapists who reviewed the data.

In the first round, 130 participants (from 14 different countries, namely Canada, China, Cuba, Denmark, France, Germany, Greece, Indonesia, Japan, Thailand, Turkey, the United Kingdom, Ukraine, Australia) returned the completed questionnaires. The study process including the number of participants in each round and the status of the statements is shown in the Flow Diagram (Figure 1). The professions of the participants are given in Table 1, and the mean years of experience was 7.35 ± 7.83 years.

Most participants (67%) reported that they regularly treat all types of spinal deformities, including adult scoliosis, adolescent scoliosis, juvenile scoliosis, kyphosis, lordosis; and the rest of the participants reported that they regularly had contact with patients with at least one or more of these types of deformities. Ninety seven (75%) participants mentioned Schroth Therapy, 9 (7%) participants mentioned Schroth Best Practice, as therapy methods; 51 (39%) mentioned bracing and 41 (32%) mentioned the use of chiropractic techniques. Many other types of treatment models such as dry cupping, massage, sports rehabilitation, swimming, ‘Spiral Stabilization of the Spine (SPS)’, and acupuncture were reported by a small number of participants.

A well-structured and easy to access conservative therapy protocol may be of great help for both patients and professionals. These protocols have been established to help find a pathway to the most appropriate way of managing individual cases. Thus patients can monitor prescriptions and proposals made by professionals and test whether these are appropriate. Within this context, overtreatment and undertreatment might be avoided for both patients and professionals (Weiss 2010). The main goal of our study was to provide the most appropriate, feasible, effective, and safe management that does not impact the lives of these patients by taking up their time and their health resources.

Currently, promising evidence shows that it might be possible to be successful in treating patients conservatively without surgery by taking into account the nature and type of the spinal deformity and the eligibility of the patient. This guideline highlights the importance of non-operative management for eligible patients, given that surgery is an invasive procedure that may be associated with more risks than the conservative options (Acaroglu et al. 2017). To date there is no specific outcomes to explain patient satisfaction post surgery (Menendez et al. 2019), and thus it may not be appropriate to be presented as the first and best option for patients.

There is no evidence that suggests that conservative management of scoliosis will have a worse outcome than surgery, (Weiss et al. 2016; Weiss & Moramarco 2013). Patients should first be treated with a conservative programme and not referred to a surgeon initially. Prescription and adherence to an early rehabilitation programme has the potential to result in successful treatment. Surgery should be considered only after reaching a situation where the symptoms cannot be managed conservatively, as it is associated with a number of long-term complications (Bettany-Saltikov et al. 2017).

Establishing proven guidelines for treatment will contribute to a more systematic approach in the conservative treatment of spinal deformities. The systematisation of conservative treatments applied in this way will serve to create a strong alternative to surgery that may have both short- and long-term risks. The guidelines may lead to further studies that will provide better levels of evidence.

There is no evidence that includes a detailed and systematic approach to the conservative treatment of spinal deformities, but related recommendations can be seen in The International Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT) consensus articles (De Mauroy, et al. 2010; Negrini et al. 2018; Weiss et al. 2006). This Delphi method has enabled some consensus on the conservative treatment of spinal conditions.

Consensus was achieved for all of the 46 statements of the guideline during the two Delphi rounds. The first round resulted in a consensus, with the majority (33 of 46 statements, 72%) of the statements being accepted. For the statements that did not reach agreement (13 of 46 statements, 28%), more detailed explanations had to be added to minimise misunderstanding or misinterpretation and to clarify the statements. Evaluation and feedback were provided by the authors about the statements for which no consensus was reached, and they were forwarded to the participants again with the authors’ permission. In the second round, the majority (11 of 13 statements, 85%) of the remaining statements reached consensus. The remaining two statements (statements 8 and 22), which did not reach consensus (but were close to the cut-off point) can possibly be considered to have reached consensus because of their high acceptance levels (Stewart et al. 2017). Thus, it may be considered that all three parts of the guideline were accepted.

Based on the statements suggested by the guideline and the opinions of its authors the following needs to be considered. In scoliosis, at stages of low growth dynamics (patients between 6 and 10 years, before the onset of the first signs of maturation), the risk of the patient becoming progressive is low; however, at the same time, there are low expectations for a recovery. So at this stage, therapy intensity can be reduced and only observation of patients with smaller curves needs to be done. Before these guidelines were drawn up, patients with curves of 20° – 35° were treated with full-time brace treatment before the main growth spurt, and often no improvement was seen. Patients then treated in this way are not sufficiently motivated at the decisive stage of puberty growth and tend not to wear braces at a time when this is most important. As a result, their curves are greatly distorted. Therefore, it may be considered that it is better not to stress patients during the stages of low growth dynamics, thereby mentally preparing them for the main growth spurt, and thus maintaining motivation for optimal treatment with full brace-wearing when appropriate. This is also the time where a clinician has the best chance for improvements, provided patients are treated with effective high correction braces (Weiss et al. 2020). Patients with scoliosis presenting to a specialist clinician before the age of six are very rare. Although there is no guideline for these patients, it is suggested that these patients are treated like those in the pubertal growth spurt, provided they are still in the growth phase (< 6 years of age).

In addition, patients benefit psychologically from intensive rehabilitation in groups during the main growth spurt period (Weiss et al. 2015). Inpatient treatment is a preferred method for patients with painful or severe pulmonary dysfunction. However, for those who have a better prognosis, out-patient sessions determined by the clinician or short-term out-patient rehabilitation prepare the patient sufficiently for home exercises. If success can be achieved by changing daily postural habits after a short rehabilitation period, these behavioural patterns may become automatic, and further intensive physical rehabilitation may not be required. It is also reported by these authors that these measures, were designed in a way that would least interfere with the quality of life of patients. (Weiss & Turnbull 2020a).

Whilst the level of evidence of conservative treatment is growing, there is still a lack of a comprehensive therapeutic guideline protocol for spinal deformities’ conservative management. As tested within our study, we believe that this guideline will create a systematic method for clinicians to use in both research and clinical practice. The expert views obtained in our Delphi study showed that most of the statements were accepted in the ‘strongly agree’ level, by most of the panellists. Thus, this proposed Guideline Protocol, derived from the Schroth Best Practice Experts’ publication (Weiss & Turnbull 2020a), was approved by the Delphi method to be used as a valid tool in the management of spinal deformities.