Preoperative prone position exercises: a simple and novel method to improve tolerance to kyphoplasty for treatment of single level osteoporotic vertebral compression fractures

Kyphoplasty (KP), developed from vertebroplasty (VP), is a minimally invasive procedure for the treatment of several vertebal diseases [1‐3]. Osteoporotic vertebral compression fractures (OVCF) is the mostly common pathologic condition treated. Compared with VP, KP has a better effect on reducing kyphosis and restoring the height of the vertebral body [4, 5]. However, KP is technically more demanding and complex, and patients undergoing such procedure are generally older and may have numerous illnesses simultaneously, which may especially impair the ability to lie in a prone position for a long time during this procedure, resulting in abandoning the surgery and increasing the risk of anesthesia-related complications [6, 7]. Many authors performed this treatment with patients under general anesthesia [8, 9]. The proper choice of anesthesia for kyphoplasty remains controversy. On the other hand, a few clinical studies reported KP under local anesthesia without detailed information [4, 10].

Ideally, KP should be performed with the patient under local anesthesia with or without conscious sedation. This study was undertaken to evaluate the effect of preoperative prone position exercises (PPE) on patient tolerance to KP under local anesthesia and to determine if such exercises would improve postoperative clinical outcome.

The baseline characteristics of both groups were comparable (Table 1). After 6 months, no patient was lost to follow-up and was excluded from the study. Before operation, one patient with severe thoracic kyphotic deformity just did PPE for 25 min each time, and the others 41 tolerated PPE well without discomfort.

All operations were performed with patients under local anesthesia with or without conscious sedation. No complications related to procedures, anesthesia and sedation occurred, which was confirmed by anesthetists’ recorded. No statistically significant difference was observed when the mean duration of operations was compared between the groups (43.8 ± 12.2 min for the exercises group and 47.3 ± 13.7 min for the control group, respectively).

The number of procedure without a pause in the exercises group was more than the control group (30/42 patients and 10/41 patients, respectively, P < 0.001), and fewer patients required intravenous sedation in the exercises group (7/42 and 28/41, respectively, P < 0.001). More patients in the exercises group were more satisfied compared to the control group (P < 0.01, Table 2).

The score of VAS decreased significantly in both groups (Table 3). In the exercises group, the mean pain score decreased from 7.8 ± 1.1 (range, 5–9) before operation to 2.4 ± 1.0 (range, 1–4) on the first postoperative day (P < 0.001) and to 2.3 ± 0.7 (range, 1–3) at 6 months after operation(P < 0.001); In the control group, VAS score improved from 7.6 ± 1.0 (range, 6–9) preoperatively to 2.4 ± 1.0 (range, 1–4) on the first postoperative day (P < 0.001) and to 2.4 ± 0.8 (range, 1–4) at 6 months postoperatively (P < 0.001). The ODI score had a similar trend. The mean ODI score decreased from 60.5 ± 6.4 (range, 48–72) preoperatively to 30.6 ± 4.9 (range, 22–42) (P < 0.001) and 30.0 ± 4.6 (range, 22–42) (P < 0.001) at 3 and 6 months, respectively, in the exercises group; The ODI score improved from 61.1 ± 5.4 (range, 48–72) preoperatively to 29.9 ± 4.1 (range, 24–41) (P < 0.001) and 30.1 ± 4.5 (range, 24–42) (P < 0.001) at 3 and 6 months, respectively, in the control group. There were no significant differences between the two groups with regard to improvement in pain and functional scores at all postoperative intervals.

As the ageing of the population of all over the world, the incidence of OVCF is likely to increase rapidly and provides a great challenge to health care workers and patients [11, 12]. KP has been proven to be an effective minimally invasive procedure for the treatment of OVCF [2‐5]. However, KP usually is performed with the patient under general anesthesia [8, 9, 13‐15]. This do cause a therapeutic dilemma that patients undergoing such procedure are generally older and may have numerous illnesses which may pose a higher risk for general anesthesia than the minimally invasive procedure per se [6, 7]. Ideally, KP is performed with the patient under local anesthesia.There are only a few clinical studies specially focusing on and giving detailed information about KP under local anesthesia with or without conscious sedation [4, 7, 10, 16, 17]. To the best of our knowledge, there is no report about preparing patients with PPE to study the effect on patient tolerance under local anesthesia and the clinical outcome in the literature so far.

The present study demonstrates that through PPE patients tolerated operation better, with fewer requiring intravenous sedation, and patients were more satisfied with such procedure. The reason why PPE improves patient tolerance under local anesthesia might be: In addition to poor physical function caused by the vertebral fracture and numerous illnesses simultaneously, psychosocial factors, including lack of confidence, low mood, anxiety, distress, may also play a key role in impairing the ability of patients with OVCF to lie in a prone position for a long time. Through the process of PPE, we built up patients’ physical adaptation to prone position and patients’ confidence, and thus improved patients’ psychological and physical tolerance to KP. During PPE, a kind of comprehensive intervention measures was implemented for preoperative preparation, including physical training, psychological support, and patient education. This reminds us that a combination of preoperative management, including physiotherapy, psychological support and patient education should be taken for such patients before operation.

Although the causes of pain in OVCF are multi-factorial, it is known that this is due mainly to micro-movement of the vertebral fracture [18]. Effective and rapid relief from pain and satisfactory clinical outcomes can be obtained after elimination of the microfractures, vertebral stabilization, and the chemical neurolytic and thermal neurolytic effect of the PMMA [5, 19]. All these could explain that although PPE improved patient tolerance and satisfaction, there were no statistically significant differences in pain alleviation and functional improvement between the two groups postoperatively. Due to various reasons, some authors still supported assisted sedation for KP or VP [7, 17, 20]. However, considering that patients with OVCF are generally older and may have numerous illnesses, reducing the use of additional sedation or general anesthesia means more safety and less potential risks for patients undergoing KP or VP treatment. Although our PPE did not improvement patients’ pain and functional scores compared with patients in the control group, it still might provide potential value to health care workers and patients.

PPE brings some advantages as follows: Firstly, it spares the use of additional intravenous sedation or general anesthesia with its potential complications [21, 22]. Secondly, it may help patients resume their daily activities early after operation. Thirdly, although we did not compare the cost of between the two groups, exercises group appears to be more cost-effective since potential adverse events related to intravenous sedation would be reduced.

Our study has a few limitations that should be mentioned. First, all patients in our study were with single level OVCF. For 2 or more than 2 levels OVCFs, the duration time of KP would be too long to use local anesthesia without intravenous sedation, and sometimes we initially recommended general anesthesia for them. So we did not enroll patients with 2 or more OVCF in the current study. Second, we did not randomize the patients between the groups because such randomization might cause ethical concerns. In our study, patients were allocated to different groups depending on the surgeons they were referred. So, any significant selection bias should have been fairly well mitigated. Third, the follow-up was 6 months. With no statistically significant differences in pain alleviation and functional improvement between the two groups during the 6-month follow-up, we did not expect that a long-term follow-up would bring significant differences. In addition, additional morbidities and mortality related to this elderly population may prohibit long-term follow-up. Other limitations of our study include the small sample size and non-multicenter study.

Considering the limitation of the current study by its small number of patients and nonrandomized comparative design, we carefully suggest that PPE may improve patient tolerance and satisfaction and reduce the need for intravenous sedation for those with single level vertebral compression fracture undergoing KP under local anesthesia. However, to confirm and validate the results of our study, large sample size and multi-center randomized controlled trial studies should be conducted.