Table 2.

Articles identified through references of articles reviewed (N = 8)

Study author	Condition/topic	Study design	Objective/aim	Participants	Main finding
Andersen et al. (2019)	Lumbar herniated disc	Prospective development of decisional aid, structured interview, simulation of consultation	To evaluate the need of SDM in a spine surgery clinic and development of a decisional aid (PtDA) including testing it	N = 39	An SDM approach was not extensively practiced in the clinic and the tool PtDA developed was usable for both patients and practitioners
Brennum et al. (2015)	Glioma	Semi-structured focus group interviews	Interviews with focus to investigate attitude toward more extensive surgery with a trade-off between neurological deficit and survival time	N = 8 patients, N = 7 experts	Large variance in definition of quality of life, and degree of risk of neurological deficit. Individual assessments necessary, and patients with well-informed decisions may even later regret it
Diaz et al. (2009)	High-grade glioma	Transversal, descriptive and correlational study, use of Hospital Anxiety and Depression Scale questionnaire (HADS) at time of discharge	A study to investigate relationship between quality of information during the surgical decision-making discussion and anxiety level in patients with high-grade glioma	N = 26	Those patients with wish to be informed regarding their condition had a lower level of anxiety, as well as in those with higher degree of understanding the information and level of satisfaction
Kim et al. (2015)	Lumbar stenosis	Prospective, follow-up questionnaires	Aim to investigate factors that influence surgical decision-making for treatment of lumbar spinal stenosis with use of preference-based shared decision-making process	N = 555	With the preference-based shared decision-making process, factors leading to a surgical decision included motor weakness, male gender and amount of visible disability
Nellis et al. (2017)	Vestibular schwannoma	Prospective data collection	Aim to investigate the decision between surgical resection or active surveillance in patients with acoustic neuroma	N = 216	Factors such as quality of life, depression, or self-esteem did not seem to influence the decision-making. Younger patients with larger and growing tumors and symptoms such as hearing loss and worse headaches were more likely to select surgical resection, possibly due to longer life expectancy compared with elderly patients even though the surgery is associated with risks
Roszell et al. (2016)	Spinal stenosis	Prospective inclusion, telephone follow-up for up to 3 years	Studying factors influencing patients to undergo spine surgery, not including patients with additional disabling conditions	N = 39 of which N = 20 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
Rozmovits et al. (2010)	Benign brain lesion	Semi-structured interviews	Aim to identify the need of information in patients who previously received neurosurgical care for benign brain tumor, arteriovenous malformation or unruptured aneurysm	N = 25	Patients require improved communication, and the wants and needs of information vary between patients
Weiner et al. (2006)	Spinal conditions	Prospective questionnaires following, and independent for, the visit with the attending surgeon	Study to investigate patients’ preferences with regards to physician and the patient’s role in the surgical decision-making, in addition to possible ethical consideration	N = 192	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