Structural equation model analysis of the length-of-hospital stay after lumbar spine surgery

Abstract

Background context Length of hospital stay (LOS) after lumbar spine surgery (LSS) can be affected by many factors. However, few studies have evaluated predictors of LOS, and all have used limited number of variables as predictors. Purpose To identify pre-surgical, surgical, and post-surgical predictors of LOS following LSS. Study Design/Setting Retrospective review of consecutive patients who had LSS at the (Blinded) Hospital from October, 2008 to April, 2012. Patient Sample 593 patients who underwent LSS consisting of laminotomy, laminectomy, or arthrodesis. Outcome Measures Dependent variable: LOS. Multiple pre-surgical, surgical, and post-surgical variables were extracted from patients’ medical records and considered as possible predictors (independent variables) of LOS. Methods Potential predictors that were significantly correlated with LOS were used as indicators to construct three latent factors; pre-surgical, surgical, and post-surgical, which were in turn used to predict LOS in a structural equation model (SEM). Results The average LOS was 4.01±2.73 days. The pre-surgical factor was indicated by age (61.97±14.49 years), prior level of function (60.5% were totally independent), prior hemoglobin level (13.70±1.36 mg/dl), and use of assistive devices (60% were assistive device users). The surgical factor was indicated by severity of illness (50.2% had minor disease severity), presence of complications (1.9%), and stay in an intensive care unit (4.0%). The post-surgical factor was indicated by post-surgical walking distance (166.43±175.75 feet), level of assistance during walking (5.18±0.81 out of 7 points), balance scores (6.18 ±1.82 out of 10 points), and bed mobility and transfer dependency scores (9.81± 1.99 out of 14 points). These three latent factors explained 47% of variation in LOS. Conclusion Post-surgical factors predicted the highest variation in LOS in comparison to pre-surgical and surgical factors and should be taken into consideration for discharge planning. Post-surgical factors are related to the patient's function, modifiable with rehabilitation and can be improved to shorten LOS. Inclusion of more reliable and standardized pre-surgical variables could improve the predictability of the model.

Enhanced recovery after surgery (ERAS) and its applicability for major spine surgery

“…The M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 9 average length of stay for patients with a post-operative complication was 5.1 ±2.3 days vs 2.9 ±0.9 days for patients with no complications (p<0.001). These findings are in keeping with Kanaan et al [37] who carried out a retrospective review of 593 patients who had had laminotomy, laminectomy or arthrodesis at a US hospital. Using a structural equation model for their analysis, they found an average length of stay of 4.01 (±2.73) days, with postsurgical factors relating to the patient's function again predicting the highest variation in LOS.…”

“…Surgical complexity can lead to an increased LOS however work by Gruskay et al (36] and Kanaan et al [37] suggest that there is scope to reduce LOS. In the study by Gruskay et al [36] in 103 patients undergoing elective, open, one to three level posterior lumbar instrumented fusion (with or without decompression) they found that intraoperative events did not affect length of stay, whilst potentially modifiable post-operative events did.…”

Thoracolumbar interfascial plane (TLIP) block: a pilot study in volunteers

“…First, all participants who volunteered for this study were younger than 50 yr, whereas back surgery is most common in patients at least 60 yr old. 18 The ability to discriminate between muscle bodies may prove more difficult with aging due to relative atrophy or anatomic changes of the spine itself. Furthermore, no participant had prior surgery in the lumbar spine, so we cannot comment on the efficacy of this technique in patients who have had prior back surgery.…”

Factors influencing the length of stay in patients with lumbar pedicle screw fixation

“…There are conflicting reports in the literature regarding the predictive value of age for LOS following lumbar fusion. [ 12 9 6 1 ] One theory is that advanced age may be associated with a higher complication rate postoperatively, thus increasing LOS. [ 11 ] However, even this theory has been challenged in the literature.…”

“…Chief among these may be patient function and walking distance. [ 6 ] There is the possibility that combining the effect of more than one variable could have a greater impact on hospital stay. The current study was done to focus the study on the three most commonly investigated and debated factors regarding LOS, and we believe convincingly shows that they only have a minor association with LOS.…”