Factors affecting the occurrence of pulmonary embolism after spinal surgery: data from the national administrative database in Japan

doi:10.1016/j.spinee.2012.10.020

The Spine Journal

Volume 12, Issue 11, November 2012, Pages 1029-1034

https://doi.org/10.1016/j.spinee.2012.10.020 Get rights and content

Abstract

Background context

Despite potentially devastating consequences, pulmonary embolism (PE) in patients undergoing spinal surgery remains poorly understood. To the best of our knowledge, few large studies have examined the prevalence and risk factors of PE after spinal surgery.

Purpose

To investigate the prevalence of symptomatic PE in patients undergoing elective spinal surgery and to identify clinical variables associated with the occurrence of postoperative PE.

Study design

A retrospective analysis of data abstracted from the diagnosis procedure combination (DPC) database, a nationally representative database in Japan.

Patient sample

We included all patients with a diagnosis of spinal canal stenosis, disc herniation, spondylosis, spondylolisthesis, trauma, metastatic tumor, or infection who underwent spinal surgery between July 1 and December 31 of 2007 and 2008, respectively.

Outcome measures

The primary end point was defined as the occurrence of postoperative PE during hospitalization. The secondary end point was in-hospital death after postoperative PE.

Methods

We analyzed the association between the occurrence of postoperative PE and clinical variables recorded in the DPC database, including age, sex, comorbidities, location of surgery, primary diagnosis, anterior/posterior approach, use of instrumentation, and duration of anesthesia.

Results

A total of 47,743 patients were identified. Of these, 50 (0.10%) developed PE and four died as a result of PE. Logistic regression analyses revealed that occurrence of PE was associated with older age (70 years or older; odds ratio [OR], 3.15; 95% confidence interval [CI], 1.15–8.69; p=.026) and longer anesthesia time (more than 360 minutes; OR, 2.19; 95% CI, 0.88–5.44; p=.092). Patients with trauma were significantly more likely to have a PE than those with spinal canal stenosis (0.27% vs. 0.09%; OR, 2.86; 95% CI, 1.14–7.18; p=.026).

Conclusions

This retrospective analysis of a nationally representative database identified older age, longer anesthesia time, and spinal trauma as risk factors for increased incidence of postoperative PE. Surgeons should be aware of the increased risk of postoperative PE in these subgroups of patients.

Introduction

Evidence & Methods

Symptomatic pulmonary embolism (PE) is an uncommon but potentially catastrophic complication following spinal surgery. Aggressive prophylactic measures, such as chemical anticoagulation, can be associated with serious potential complications as well. In this study, the authors evaluated a large database from Japan to assess the incidence and associated risk factors for PE in that population.

The authors found that older age, time under anesthesia, and a spine trauma diagnosis were risk factors for PE. Symptomatic PE was noted in one of 1,000 patients. The PE was fatal in less than one in 10,000, with mortality being similarly associated with increased age, longer operative times and surgery for traumatic injuries.

These findings are consistent with previous data and add statistical support to the impression that PE risk is very low and that even in most high-risk patients aggressive prophylactic measures need to be carefully weighed against the concomitant risks of pharmacologic prophylaxis.

—The Editors

Pulmonary embolism (PE) is a potentially life-threatening complication after major surgical procedures. The issue of postoperative PE after joint arthroplasty has been well studied [1], [2], [3], but PE after spinal surgery is less well understood, presumably because of its relative rarity. Reported prevalences of PE after spinal surgery vary greatly, ranging from 0% to 7.6% [4], [5], [6]. This wide variation in estimated values may be attributable to small sample sizes and biases in the selection of the study populations. To the best of our knowledge, few large studies have examined the prevalence and risk factors of PE after spinal surgery.

In this study, we therefore investigated the prevalence of symptomatic PE in patients undergoing spinal surgery using a nationally representative inpatient database in Japan. We further performed multivariate analyses to identify clinical variables associated with the occurrence of postoperative PE.

Section snippets

Materials and methods

The diagnosis procedure combination (DPC) is a case-mix system in Japan that is similar to the diagnosis-related groups identified by the US Medicare system. This patient classification system was launched in 2002 by the Ministry of Health, Labour and Welfare of Japan and linked with a lump-sum payment system. The key aims of the DPC system are to implement a standardized electronic claim system and to provide transparency of hospital performance [7]. All the 82 teaching hospitals in Japan are

Results

We identified 49,867 surgical patients who met the above-mentioned diagnostic criteria during the survey period. We excluded 2,124 patients (4.3%) who received thromboprophylactic agents such as low–molecular-weight heparin because they were presumed to have clinical characteristics different from the remaining subjects. Subsequently, a total of 47,743 eligible patients were identified, including 19,587 patients (41.0%) with spinal canal stenosis, 11,605 (24.3%) with disc herniation, 8,082

Discussion

In this study, we examined the prevalence and risk factors of postoperative PE after spinal surgery by analyzing data from more than 47,000 patients. The main strength of this study was the use of the DPC database, which is a national administrative inpatient database in Japan, covering almost half of all acute care hospitalizations. Use of this nationwide database allowed us to examine the prevalence and risk factors of PE despite its relatively rarity. Our results estimated the overall

Acknowledgments

This study was funded by grants-in-aid for Research on Policy Planning and Evaluation from the Ministry of Health, Labour and Welfare, Japan.

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: Author disclosures: KM: Nothing to disclose. HC: Nothing to disclose. HY: Nothing to disclose. NH: Nothing to disclose. HH: Nothing to disclose. SM: Nothing to disclose. KT: Nothing to disclose. HK: Nothing to disclose. KN: Nothing to disclose.

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Clinical StudyFactors affecting the occurrence of pulmonary embolism after spinal surgery: data from the national administrative database in Japan

Abstract

Background context

Purpose

Study design

Patient sample

Outcome measures

Methods

Results

Conclusions

Introduction

Section snippets

Materials and methods

Results

Discussion

Acknowledgments

Urology

J Orthop Sci

Lancet

Surg Neurol

Frequency and timing of clinical venous thromboembolism after major joint surgery

J Bone Joint Surg Br

Fatal pulmonary embolism, death rates and standardized mortality ratios after primary total hip replacement in a joint replacement centre

Hip Int

Standardized mortality ratios and fatal pulmonary embolism rates following total knee replacement: a cohort of 936 consecutive cases

J Knee Surg

Thromboembolic disease after combined anterior/posterior reconstruction for adult spinal deformity

Spine

Clinical Study
Factors affecting the occurrence of pulmonary embolism after spinal surgery: data from the national administrative database in Japan