Presurgical biopsychosocial factors predict multidimensional patient: outcomes of interbody cage lumbar fusion

Abstract

Background context

Interbody cage lumbar fusion (ICLF) has been advanced to improve arthrodesis; however, little attention has been given to quality of life and functional outcomes. Studies suggest that psychosocial factors may be important modifiers of low back surgical outcomes.

Purpose

To depict outcomes of ICLF surgery across multiple dimensions and to investigate presurgical biopsychosocial predictors of these outcomes.

Study design/setting

A retrospective-cohort research design was used that involved completion of presurgical medical record reviews and postsurgical telephone outcome surveys at least 18 months after surgery. Presurgical variables included in a regression model were age at the time of surgery, spinal pathophysiology rating, smoking tobacco, depression, and pursuing litigation.

Patient sample

Seventy-three patients received ICLF, and of those 56 patients completed the outcome survey an average of 2.6 years after surgery.

Outcome measures

Outcome measures consisted of arthrodesis status, patient satisfaction, back-specific functioning, disability status, and quality of life.

Results

Although arthrodesis occurred in 84% of the patients, nearly half were dissatisfied with their current back condition. Functional status was worse than expected, and 38% were totally disabled at follow-up. Regression analyses revealed tobacco use, depression, and litigation were the most consistent presurgical predictors of poorer patient outcomes.

Conclusions

Overall, despite a high rate of arthrodesis, ICLF was not associated with substantial improvements in patient functioning. Presurgical biopsychosocial variables predicted patient outcomes, which may help improve patient selection and possible targeted interventions.

Introduction

Chronic low back pain (LBP) is one of the most common conditions resulting in surgery [1], [2]. One particular surgical intervention, lumbar fusion, has seen a dramatic increase in use since the 1980s [3]. Lumbar fusion now ranks as the second most common low back operation with nearly 192,000 performed annually [4]. The effectiveness of this surgery for treating LBP, however, remains controversial. For instance, in a meta-analysis [5] of spinal fusion studies from 1966 to 1991, satisfactory clinical outcomes ranged from only 15% to 95% (mean=68%). A myriad of possible explanations for mixed lumbar fusion outcomes exist, including instrumentation failure, inadequate surgical technique, poor patient selection, and psychosocial variables such as litigation or secondary gain and psychological distress [5], [6], [7], [8], [9], [10].

More recently, interbody cage lumbar fusion (ICLF) has been advanced in an effort to improve outcomes. Although a small number of studies [11], [12], [13] presented preliminary support for this spinal fusion technique, few were conducted independent of the developers of ICLF. In one such study [14], the interbody cages did not show the superior fusion rates as compared with other surgical techniques initially reported by the developers of the apparatus. Poor outcomes from such surgical procedures could have a considerable effect on the limited resources of health care systems and subject patients and their families to increased financial and physical burdens. Moreover, the primary emphasis within the extant spinal fusion literature is on biomechanical outcomes with little attention given to quality of life and functional ability. Thus, it appears that evidence about the long-term benefits of the ICLF is, at this time, limited.

Characteristics of patients at risk for poor fusion outcomes are not clearly identified in the literature. For instance, examination of patients' age and smoking status has produced mixed results [6], [8], [9], [11], [13], [15], [16], [17], [18], [19] with regard to arthrodesis (ie, solid fusion) and patient outcomes. More consistent findings with patients with LBP, patients with chronic pain, and patients undergoing other surgical procedures [20], [21], [22], [23], [24] suggest a potentially important relationship between psychosocial factors, such as presurgical depression, smoking, and litigation status, and multidimensional ICLF outcomes. Patient characteristics and psychosocial factors could offer a basis for targeted interventions and improving patient selection, thereby also improving spinal fusion outcomes. To date, these characteristics are not adequately addressed. Therefore, the purpose of the present study was to examine ICLF outcomes across several qualitatively different variables and to investigate a multivariate predictive model based on biopsychosocial presurgical variables.