Shared decision-making in neurosurgery: a scoping review

Background In modern neurosurgery, there are often several treatment alternatives, with different risks and benefits. Shared decision-making (SDM) has gained interest during the last decade, although SDM in the neurosurgical field is not widely studied. Therefore, the aim of this scoping review was to present the current landscape of SDM in neurosurgery. Methods A literature review was carried out in PubMed and Scopus. We used a search strategy based on keywords used in existing literature on SDM in neurosurgery. Full-text, peer-reviewed articles published from 2000 up to the search date February 16, 2021, with patients 18 years and older were included if articles evaluated SDM in neurosurgery from the patient’s perspective. Results We identified 22 articles whereof 7 covered vestibular schwannomas, 7 covered spinal surgery, and 4 covered gliomas. The other topics were brain metastases, benign brain lesions, Parkinson’s disease and evaluation of neurosurgical care. Different methods were used, with majority using forms, questionnaires, or interviews. Effects of SDM interventions were studied in 6 articles; the remaining articles explored factors influencing patients’ decisions or discussed SDM aids. Conclusion SDM is a tool to involve patients in the decision-making process and considers patients’ preferences and what the patients find important. This scoping review illustrates the relative lack of SDM in the neurosurgical literature. Even though results indicate potential benefit of SDM, the extent of influence on treatment, outcome, and patient’s satisfaction is still unknown. Finally, the use of decision aids may be a meaningful contribution to the SDM process. Supplementary Information The online version contains supplementary material available at 10.1007/s00701-021-04867-3.


Introduction
Advances in the medical field during the last decades have led to a range of available options for use in the decisionmaking process [36]. The development of the healthcare system as a whole has shifted toward a higher degree of person-centered care, which incorporates patients and their values, needs, and preferences [12,40]. The tool of shared decision-making (SDM) in clinical practice has gained interest mainly during the last decade. SDM aims to include the patient to a larger extent in decision-making regarding the next treatment step [3]. The use of SDM overall in the medical field has significantly increased over the years, from between 1 and 50 publications per year between 1968 and 1994, to numbers in the thousands during the most recent years [7].
While an informed consent is based on presenting information to the patient by the physician, SDM includes the patient and the process is based on mutual respect and participation in the discussion [8]. There is, however, no clear definition of SDM [26] but generally SDM can be identified through four steps: first, the patient is informed of the need for a decision regarding a health issue and the patient's own thoughts are important. Secondly, the process continues with a presentation of the pros and cons with the different options by the healthcare provider, followed by the third step which is a discussion led by the professional to support the patient in the thought process in an informative way and, lastly, in the fourth step, the patients wish to decide is discussed and they either make decision or defer it [49]. The discussion should also lift the possible complications and management of these, so the patient can fully grasp the associated risks with treatment option. The logic behind the core SDM model is that what the physician deems relevant may differ from what is considered important by a patient capable to decide. Across multiple scenarios, SDM strives to integrate the best available clinical evidence with the patient's values and preferences [14,30,47].
A large systematic review of SDM in the field of surgery showed that 29.3% of patients and 43.6% surgeons experienced that their consultation was performed in a SDM fashion, illustrating the discrepancy between perception of what SDM is and in what manner the consultation was performed [10]. The experience of lack of information is not uncommon, and one way to improve this may perhaps be to actively include the patient in decision-making regarding their own care [17,21,44,56].
Neurosurgery is considered a high-risk surgical field [9,41]. Moreover, asymptomatic or minimally symptomatic lesions are nowadays more often encountered in clinical practice due to increased availability of radiologic diagnostics and a generally older population [33,37,45,46]. It is not always a decision on whether to treat or not, but significantly different treatment alternatives may be relevant (e.g., endovascular treatment versus clipping for intracranial aneurysms or radiosurgery versus resection for vestibular schwannomas). Thus, the risk-benefit profile in association with the various options requires a deeper patient involvement in the decision-making, and it can be considered to be our responsibility as professionals to discuss the different alternatives where they exist. Furthermore, many patients seem to prefer SDM regarding medical decisions; however, some patients with brain tumors may suffer from cognitive impairment and be unable to make the decision by themselves and would benefit from support from relatives [7,17,18,20].
Even though the awareness regarding SDM is increasing, it is not widely incorporated in clinical practice [24]. In neurosurgery, we expected the SDM literature to be limited. The aim of this scoping review was to evaluate the current status of the literature regarding SDM in neurosurgery.

Design -literature review
A literature review was performed in order to present the existing literature on SDM in neurosurgery and to explore the main themes.

Search strategy
The literature search was performed using the databases PubMed and Scopus on February 16, 2021. It was performed by a trained librarian, assisted by the review authors (AC, AG). Selection of database was based on the area of the question. The search strategy consisted of two blocks: neurosurgery and shared decision-making. To directly select keywords related to the topic of interest, we included MeSH (Medical Subject Headings) terms of the National Library of Medicine to identify relevant articles in PubMed as well as relevant keywords and synonyms. Additionally, corresponding search terms were used in the literature search performed in Scopus. The search strategy was based on keywords used in existing literature of shared decision-making in neurosurgery. It included articles published from 2000 up to the search date February 16, 2021. A detailed description of the used search strategy is presented in Supplementary Tables 1  and 2. To identify any additional relevant articles, references of all articles selected for reviewing in full text were examined. A PRISMA flowchart was created [27].

Eligibility criteria
Eligible criteria were prospective and retrospective original full-text available, peer-reviewed articles published between from 2000 up to the search date February 16, 2021, patients 18 years and older, and articles regarding shared decisionmaking in neurosurgery. Exclusion criteria were SDM from other perspectives than patients and articles written in other languages than English or the Scandinavian languages (See the PRISMA flowchart for article inclusion (Fig. 1)). The 3D printed model showed promise as a tool to include patients in the decision-making process and for patients to better understand situation, possible treatment strategies, and risks All articles identified by database search were screened based on information in titles and abstracts. Articles selected during the screening were reviewed in full text by three review authors separately (AC, AG, TGV) and the discordant articles (N = 3) were reviewed by a senior consultant in neurosurgery (ASJ).

Analysis and synthesis of results
Included articles were collated and summarized for reporting results. No meta-analysis was planned as a small sample with large heterogeneity was anticipated. The study was planned to only be descriptive in character. The articles were further analyzed using a thematic analysis grid. We aimed primarily to identify the patient groups included in SDM processes, the methods used to plan or assess SDM interventions, the type of decision topics addressed by SDM interventions, and the most relevant findings on the field of neurosurgery related to SDM.

Search results
A total of 639 unique articles were found through database searching and reference lists. After screening articles by title, 369 articles were excluded for the following reasons: age range of 17 years and younger, SDM outside of neurosurgery, not assessing SDM and not original articles. Of the remaining 270 articles, a further 228 articles were excluded after screening of the abstract. Finally, a total of 42 articles were assessed in full text for eligibility, whereof 18 studies were excluded due to not assessing SDM and 2 studies for not being original articles. This resulted in the inclusion of 22 studies: 14 studies identified through literature searches [2,6,16,23,25,28,29,32,35,39,[51][52][53]57] and 8 articles through screening of reference lists [1,5,11,22,34,42,43,54] (see Tables 1 and 2, respectively and see the PRISMA flowchart for more information (Fig. 1)).
We observed a heterogeneity in the methods used for the included articles. Thirteen articles were prospective with underwent surgery The surgical decision-making was influenced more by the issues related to health and quality of life, rather than other factors such as pain or disability inclusion prior to treatment or at first consultation. In 15 studies, questionnaires were used and interviews were performed in 6 studies. The timing of questionnaire administration differed, ranging from before consultation, right after consultation/intervention to follow-up up to 3 years after first consultation/intervention. Three main themes were identified: I. Evaluation/identification of factors that influence patients' decisions; II. Evaluation of SDM intervention effects; and III. Evaluation of SDM aids.
The diagnosis included in these discussions was vestibular schwannoma, lumbar spinal stenosis, Parkinson's disease, glioma, benign brain tumors, arteriovenous malformations, unruptured aneurysms, or brain metastases. Topics addressed were conservative treatment versus surgical treatment, "awake" methods versus "asleep" methods, stereotactic radiosurgery (SRS) versus SRS plus whole-brain radiotherapy, and the clinical dilemma of a trade-off between neurological function and survival time.

Evaluation of SDM intervention effects
The articles evaluating SDM intervention effects reflected the degree of SDM involvement for a total of 1141 patients over 6 articles [1,16,25,32,39,51]. The diagnosis reported was glioma (84 patients), vestibular schwannoma (660 patients), lumbar disk herniation (39 patients), cervical spinal stenosis (1 patient), or any unspecified neurosurgery-related patient group (364 patients). The methodologies presented in these articles made use of questionnaires such as Hospital Anxiety and Depression Scale (HADS), short form-36 (SF-36) measuring quality of life, Pain Disability Index (PDI), Beck Depression Inventory (BDI), and questionnaires made for their study aim. One study was a case report.
Decision topics addressed by the SDM process were mainly conservative treatment versus surgical treatment or radiotherapy and the risks of surgery. Furthermore, the type of results reported included successful Their findings showed that patients in need of spinal surgery often want the surgeon to make the decision, and in more complex cases, the patient should be fully informed to help the patient make an informed decision and mixed intervention outcomes. Successful SDM interventions reported high levels of patient involvement related to equal levels of patient satisfaction with the provided care (Tables 1 and 2). In contrast, mixed intervention outcomes were signaled by deficits in the quantity of SDM interventions being exercised. The instruments used to assess the degree of SDM included mostly questionnaires.

Evaluation of SDM aids
SDM aids were directly discussed for the diagnosis lumbar disk herniation (270 patients) and glioma (11 patients) in three articles [1,2,52]. The methodologies employed made use of structured interviews, semi-structured interviews, and questionnaires. One of the articles aimed to evaluate SDM aids and factors that influence patients' decisions. Decision topics addressed by the SDM related to the SDM aids were not at the center of the discussion. However, SDM aids such as decision boards, video disks, and tumor 3D models were mainly found to require further testing to assess their effectivity. The results reported in these articles regarded the levels of satisfaction, barriers, and facilitators regarding the use of such SDM aids (Tables 1 and 2).

Discussion
In this scoping review we present the current literature regarding SDM in neurosurgery. The limited extent of SDM use in the neurosurgical field was notable, and conditions more commonly included were spinal disorders and vestibular schwannomas. A wide range of methods were used, but the application of questionnaires dominated.

Design and characteristics of included studies
There was a wide variety of different methods used in the included studies, from prospective studies with follow-up questionnaires to more explorative studies with 3D models, suggesting the lack of common methods to evaluate SDM. Although designs differed, the common aim of evaluating and incorporating SDM was present in all articles. There was a recurring theme of shortfall of information in both preoperative and postoperative settings. Some articles raise concerns that not all treatment options were presented, or that the side effects of the treatment options were not presented [29]. For the patients to be able to participate in decision-making, all the different treatment options with benefits and risks should be offered to the patient.

Practical application of SDM
Many healthcare professionals in different medical fields agree that SDM is important for the patient when making a decision, but the practical application of SDM may be more challenging [19,50]. Different decisional aids have been used for facilitating SDM with the patients, although the methods used seem to be unique for each article. van [1]. Their patient decision aid was a paper leaflet with information regarding advantages and disadvantages with each surgical and non-surgical option offered, treatment outcomes, how symptoms may affect the patient and rate of severe complications after surgery. A decisional aid like the one developed by Andersen and co-authors covers the important steps in the SDM process, while also providing the patient with information that might be overlooked or considered less important by the surgeon [1].
It has been discussed that cognitive impairment associated with the tumor may cause difficulties in SDM for patients with brain tumors [20,38]. Hewins et al. published a review on the effects of brain tumors on patients' decision-making capacity, an important aspect in the process of SDM [20]. They concluded that the capacity for consenting to medical treatment in patients with brain tumors may need additional assessment of cognitive abilities to test the ability to consent for both treatment and research. In these patients, the support of relatives is important, and information regarding possible treatment options is also of high relevance to relatives, who often feel their needs are unmet regarding communication and information [13,44,48]. Involving patients and relatives more in the care may increase the understanding and can perhaps lead to better treatment compliance and overall well-being.

Neurooncology
The articles in the field of neurooncology range from more biologically benign lesions to high-grade gliomas [43,52]. Vestibular schwannoma was the most common tumor in which SDM was used in the decision-making process [16,28,29,35], perhaps due to the different treatment modalities available (radiosurgery, surgery, radiotherapy, and wait-andscan) [15,43]. The treatment of vestibular schwannoma is associated with specific risks and selection of the optimal modality is a careful process [4,55].
In the study by Moshtaghi et al., the authors sent out surveys to patients diagnosed with vestibular schwannoma and evaluated the factors that affected the decision-making process from the patient's own perspectives [28]. Their finding included that 59% received information regarding different treatment options, and 80% visited multiple vestibular schwannoma specialists, suggesting the first visit left the patient with a feeling of uncertainty regarding their decision. The number of neurootologists consulted correlated with higher decision satisfaction. Furthermore, in additional studies, 16% of the 414 patients who underwent surgery felt pressured to select a surgical treatment for their vestibular schwannoma [28]. In an additional study, 69% of the patients only received information regarding one treatment option, mainly surgery, and usually not enough information regarding side effects of the treatments [29]. In the study by Graham et al., 20% of patients with vestibular schwannoma experienced decisional conflict and involving patients in decisionmaking reduced the degree of uncertainty [16]. The lack of information in an early stage may lead to waste of healthcare resources by patients seeking confirmation from multiple specialists for the same issue. Perhaps the lack of information can be improved by decisional aids to fill the information gap and fully inform the patients about possible treatment options and risks associated with the options presented.
When further exploring SDM in the field of neurooncology, it seems that most patients take an active role if information is presented adequately, as presented by Zeng et al. [57]. They illustrate how to include patients with brain metastases in a patient-centered approach where a key element is the use of comprehensible information. When the patients were presented with clear information, they could decide accordingly what was important for them.
Brennum et al. challenged the established Hippocratic principle of "primo non nocere" in favor of maximal resection and survival [5]. The participating experts and patients discussed the balance between neurological function and longer survival and found that offering more extensive surgery could be ethically acceptable. Although, even informed patients accepting neurological deficit for the benefit of longer survival may regret their decision if the outcome with neurological deficit is difficult to comprehend. The risk that a patient misunderstands the surgeon is a risk with surgery beyond maximal safe resection, as they most often lack the experience of neurological deficit and may perhaps idolize the difficult decision they face [31]. Still, a more person-centered care where the patient is considered a partner in the decision-making process may improve health outcomes and increase patient satisfaction [12].

Strengths and limitations
The wide spectrum of approaches to SDM may indicate that implementation of SDM is challenging. In this study, we included a variety articles to provide a thorough update of the use of SDM in neurosurgery. Although our methodology followed a broad approach, we found a limited number of studies, a large methodological variability between studies, and a variable sample size in the selected studies, indicating that SDM is still in its infancy in neurosurgery. Additionally, we identified eight articles through references suggesting some keywords were not covered by the search blocks. This may be due to the fact that most of the articles (7) identified through references discussed topics related to factors that influence patients' decisions and were not aimed to primarily assess the effects of decision-making processes. Furthermore, there may be more studies that explored the topic of SDM peripherally, or through use of proxies, that escaped the scope of our search.

Conclusion
Shared decision-making is a tool to involve patients in the decision-making process, to provide optimal care also considering patients preferences, and to include what they feel is important in the decision process. This review illustrates the relative lack of SDM in the neurosurgical literature and can hopefully serve as useful information regarding SDM and be used as a foundation to better involve neurosurgical patients in the decision-making process. Although the results provided indicate that there may be a potential benefit of using SDM, to what extent and how SDM influences treatment provided, outcome, and patient satisfaction remains to be seen. Finally, the use of decision aids may be a meaningful contribution to the SDM process.