Use of a decision aid did not decrease decisional conflict in patients with carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is the most common peripheral neuropathy affecting the upper extremities, and it is characterized by a tingling sensation in the median nerve distribution and/or thenar muscle weakness. Although carpal tunnel release is a definitive treatment, there are several treatment options that depend on the severity of the symptoms and on the underlying cause [1, 2]. In addition, as the natural history of the condition remains unclear, questions may remain for both patients and physicians as to when and which treatment is most appropriate [3‐5]. Therefore, the optimal decision-making for treatment depends not only on the probabilities of various outcomes with each strategy but also on the patient's relative preferences for the possible outcome states [6]. In this sense, support for a model of shared decision-making, in which clinicians and patients jointly make a decision, is a growing expectation for patients with CTS [7, 8]. However, decisional conflict can emerge from this decision-making process, when information about risks and benefits is not effectively communicated or discussed according to personal values [6, 7, 9].

Patients with CTS can receive information from a variety of sources, including the Internet, magazines, pamphlets, and TV programs. However, the quality and completeness of the information obtained from the above mentioned sources need to be improved [10, 11]. Therefore, a decision aid is proposed in order to provide information to patients and to involve patients in the surgical decision-making process [12]. Decision aids can take many forms, and the most common are comprised of a combination of written and oral information, personal counseling, videotapes, and interactive computer-based multimedia programs [6]. A study asking whether a directive to an Internet site enhances the doctor-patient interaction did not find any difference in patients’ knowledge and satisfaction levels in patients with CTS [13]. However, the effect that a decision aid has on patients’ decisional conflict in their decision-making has not been investigated. Therefore, we aimed to determine whether a decision aid helps patients with CTS experience less decisional conflict regarding their decision-making for surgery.

Two hundred and twenty five patients were assessed for eligibility and 80 patients were randomized to either a decision aid group (n = 40) or a control group (n = 40). Thirty-two patients from the decision aid group and 34 from the control group opted for surgery and were included in the final analysis (Fig 1). Both groups were comparable in terms of demographic characteristics, education, comorbidities, history of a previous operation, symptom duration, and symptom severity assessed with DASH scores (Table 2).

The decisional conflict scores did not differ between the decision aid and the control groups (22 vs. 23, p = 0.76). The scores of the patients’ satisfaction with their decisions also did not differ between the two groups (1.8 vs. 1.7, p = 0.80). However, the decision aid group patients had greater knowledge of CTS than those in the control group (7.4 vs. 6.6; p = 0.04). Both the DCS and knowledge scores demonstrated a normal distribution.

An analysis of all patients in both groups revealed that there was no correlation between decisional conflict and knowledge scores (r = 0.03, p = 0.76). However, a negative correlation was found between decisional conflict and DASH scores (r = −0.29, p = 0.02), meaning that those with less severe symptoms had greater decisional conflict. No significant correlation was found between decisional conflict and the other variables, such as age, education, comorbidities, history of a previous operation, and symptom duration.

Patients with CTS can be informed through a variety of sources and several treatment options are available. However, the effect that a decision aid has on patients’ decisional conflict regarding surgery on their knowledge of their condition regarding surgery is not known. This study demonstrates that although patients with CTS who received a decision aid had greater knowledge of their condition, the decision aid did not significantly reduce decisional conflict or increase satisfaction with the decision when compared to patients who were given regular information by the surgeon. However, this study does show that patients with less severe symptoms had greater decisional conflict regarding surgery.

In the present study, the decision aid did not reduce decisional conflict, which is contrary to what was reported in previous reviews [12, 18]. However, a few studies likewise reported no difference in decisional conflict, such as in studies of patients with an asymptomatic abdominal aortic aneurysm [17], or patients with advanced colorectal cancer who were considering chemotherapy [19]. The reasons for which no differences were found were not presented in these studies [17, 19]. O’Connor et al. reported that decisional conflict scores of 25 or lower are associated with a follow-through with decisions, whereas those exceeding 38 are associated with a delay in decision making [20]. Therefore, the low decisional conflict scores in both groups obtained by the current study could indicate that patients with CTS may already feel comfortable with the usual care, resulting in a ceiling effect for an added decision aid. This could also be the reason for which no difference in satisfaction was reported for the decision making process [18]. The analysis of all patients revealed, however, that patients with more severe symptoms had less decisional conflict. This is consistent with the previous finding that the severity of subjective symptoms is the most important reason of all factors that affect the willingness to undergo carpal tunnel release [21].

In this study, the patients in the decision aid group had greater knowledge than those in the control group, which is consistent with observations from previous studies on decision aids for patients facing a surgical treatment decision for other conditions [12]. Furthermore, a recent Cochrane review on decision aids for people facing health treatment or screening decisions revealed that 42 out of 56 studies comparing decision aids to usual care indicated that people exposed to decision aids had higher average knowledge scores, with a mean of 13.34% (95% Confidence interval 11.17 to 15.51) [18]. The review also revealed that people exposed to detailed decision aids had higher knowledge scores, but the effect was small with a mean difference of 5.52%. On the contrary, Aung et al. found that a directive to an Internet site did not enhance patients’ knowledge of CTS [13]. They tested the patients’ knowledge 3–4 weeks after the first visit when they recommended the web site, which could make the patients forget the information. In addition, the information on the web site could be difficult to read compared to the cartoon-based video format used in the current study. The expected knowledge results are contrary to the survey by Hageman et al., which found that patients with CTS favored web-based information more than surgeons, who valued a video format for information [22]. Future studies may determine which type of decision aid can better increase knowledge, and whether the knowledge is maintained and helps patients cope with postoperative recovery.

The decision aid used in this study was a series of cartoons. There are a few studies supporting the use of cartoon animations to inform patients. Tou et al. showed that preoperative 2D animation information is an effective medium for delivering information to patients undergoing bowel surgery and can reduce anxiety related to surgery [23]. Imamura et al. also showed that an internet-based cognitive behavioral therapy program in Manga format was effective in improving depression in the general working population [24]. We consider that cartoons can show the important points about anatomy and surgery more simply than real operative photographs. However, the optimal medium for production of decisional aid remains unknown.

There are several limitations to this study. First, this study was performed in a tertiary referral setting and all of the patients had been referred by other physicians. Therefore, the doctor patient-relationship with their previous physician or the information that they were previously provided could have affected the patients in our study. Second, both the patients and the physician were not blinded to the allocation. The patients knew the aims of the study, and those allocated to the decision aid group could have participated more actively in the knowledge test, a phenomenon known as the Hawthorne effect [25]. Third, the knowledge questionnaire was not a validated form, as there is currently no validated survey to test patients’ knowledge about CTS. However, the scores showed a normal distribution, and the chances of getting answers correct by guessing would be low since the test was composed of multiple-choice questions.

This study found that a decision aid does not reduce decisional conflict in patients with CTS, although it can help the patients be better informed. This study suggests that although a decision-aid is effective for patient education, doctor-patient communication should be more emphasized for patients with less severe symptoms, as they can have greater decisional conflict.