P20. Risk factors for postoperative unexpected ambulatory status after spinal surgery for metastatic spinal tumor

Background Context

Surgical treatment for metastatic spinal tumors is performed to improve ambulatory status or quality of life (QOL). However, the postoperative complication rate for surgical treatment in patients with cancer is high, and there are many cases in which patients fail to gain the ability to walk, resulting in poor outcomes. There is no large-scale study that discussed risk factors for postoperative poor ambulatory status, although many case series and meta-analyses suggested several risk factors such as preoperative non-ambulatory.

Purpose

The purpose of the study was to investigate risk factors for patients with postoperative unexpected ambulatory status using large-scale in-hospital data.

Study Design/Setting

Analysis of nationwide administrative hospital discharge data.

Patient Sample

This study included spinal surgery cases for metastatic spinal tumors including vertebroplasty using the Diagnosis Procedure Combination (DPC) database: a national inpatient database in Japan, from 2018 to 2019. We excluded cases with surgery of total en bloc spondylectomy, cases of death during hospitalization, and cases with whose Barthel Index data at admission or discharge were missing.

Outcome Measures

Postoperative unexpected ambulatory status was defined as (1) nonambulatory at discharge or (2) a decrease in mobility score of Barthel Index between admission and discharge.

Methods

The risk factors for postoperative unexpected ambulatory status were analyzed using multiple logistic regression analysis, adjusting for age, gender, surgical volume, primary site of tumor, surgical procedure, nonskeletal metastasis, comorbidity, and ambulatory status at admission.

Results

A total of 1786 eligible patients were analyzed. There are 1061 (59%) ambulatory patients on admission and 1249 (70%) on discharge. Postoperative unexpected ambulatory status was observed in 597 patients (33%), with a significantly lower rate of discharge to home (41%/81% p<.001) and a longer postoperative hospital stay (46.2 days/31.4 days p<.001). Multivariate analysis indicated that risk factors for postoperative unexpected ambulatory status were male (odds ratio [OR] 1.44, p=.002), laminectomy without fusion (OR 1.55, p=0.03), comorbidity (OR 1.35, p=.01), and preoperative non-ambulatory status (OR 6.61, p<.001).

Conclusions

Laminectomy without fusion is performed in limited pathology for metastatic spinal tumors when the spinal instability is small such as involvement in the posterior element only, or the risk of invasive surgery is high due to comorbidity. In this study, laminectomy without fusion was one of the risk factors for postoperative unexpected ambulatory status, which accounted for 33% of all cases. The indication for surgery with laminectomy alone needs further consideration.

FDA Device/Drug Status

This abstract does not discuss or include any applicable devices or drugs.