Development and validation of a novel thoracic spinal stenosis surgical invasiveness index: a single-center study based on 989 patients

BACKGROUND CONTEXT

Surgical invasiveness indices have been established for general spine surgery (surgical invasiveness index [SII]), spine deformity, and metastatic spine tumors; however, a specific index for thoracic spinal stenosis (TSS) has not been developed.

PURPOSE

To develop and validate a novel invasiveness index, incorporating TSS-specific factors for open posterior TSS surgery, which may facilitate the prediction of operative duration and intraoperative blood loss, and the stratification of surgical risk.

STUDY DESIGN

A retrospective observational study.

PATIENT SAMPLE

Overall, 989 patients who underwent open posterior TSS surgeries at our institution during the past 5 years were included.

OUTCOME MEASURES

The operation duration, estimated blood loss, transfusion status, major surgical complications, length of hospital stay, and medical expenses.

METHODS

We retrospectively analyzed the data of 989 consecutive patients who underwent posterior surgery for TSS between March 2017 and February 2022. Among them, 70% (n=692) were randomly placed in a training cohort, and the remaining 30% (n=297) automatically constituted the validation cohort. Multivariate linear regression models of operative time and log-transformed estimated blood loss were created using TSS-specific factors. Beta coefficients derived from these models were used to construct a TSS invasiveness index (TII). The ability of the TII to predict surgical invasiveness was compared with that of the SII and assessed in a validation cohort.

RESULTS

The TII was more strongly correlated with operative time and estimated blood loss (p<.05) and explained more variability in operative time and estimated blood loss than the SII (p<.05). The TII explained 64.2% of operative time and 34.6% of estimated blood loss variation, whereas the SII explained 38.7% and 22.5%, respectively. In further verification, the TII was more strongly associated with transfusion rate, drainage time, and length of hospital stay than SII (p<.05).

CONCLUSIONS

By incorporating TSS-specific components, the newly developed TII more accurately predicts the invasiveness of open posterior TSS surgery than the previous index.

Validation of a surgical invasiveness index in patients with lumbar spinal disorders registered in the Spine Tango registry

INTRODUCTION

Being able to quantify the invasiveness of a surgical procedure is important to weigh up its associated risks, since invasiveness governs the blood loss, operative time and likelihood of complications. Mirza et al. (Spine (Phila Pa 1976) 33:2651-2661, 2008) published an invasiveness index for spinal surgery. We evaluated the validity of a modified version of the Mirza invasiveness index (mMII), adapted for use with registry data.

METHODS

A cross-sectional analysis was performed with data acquired from the Spine Tango registry including 21,634 patients. The mMII was calculated as the sum of six possible interventions on each vertebral level: decompression, fusion and stabilization either on anterior or posterior structures. The association between the mMII and blood loss, operative time and complications was evaluated using multiple regression, adjusting for possible confounders.

RESULTS

The mean (± SD) mMII was 3.9 ± 5.0 (range 0-40). A 1-point increase in the mMII was associated with an additional blood loss of 12.8% (95% CI 12.6-13.0; p < 0.001) and an increase of operative time of 10.4 min (95% CI 10.20-10.53; p < 0.001). The R² for the blood loss model was of 43% and for operative time, 47%. The mean mMII was significantly (p < 0.001) higher in patients with surgical complications (4.5 ± 5.6) and general medical complications (6.5 ± 7.0) compared to those without (3.8 ± 4.9). Our results were comparable to those reported in the original publication of Mirza et al. CONCLUSION: The mMII appeared to be a valid measure of surgical invasiveness in our study population. It can be used in predictor models and to adjust for surgical case-mix when comparing outcomes in different studies or different hospitals/surgeons in a registry.

Use of Intraoperative Tranexamic Acid and Wound Complications in Spine Surgery: A Retrospective Cohort Study

Study Design

A retrospective cohort study.

Purpose

This study aims to examine the effect of tranexamic acid (TXA) on postoperative wound healing in spine surgery.

Overview of Literature

TXA (Cyklokapron, Hexakapron) is a widely used anti-fibrinolytic drug that is shown to be effective in mitigating hemorrhage during and after surgery by competitively blocking plasminogen in fibrinolytic cascade. Plasminogen also plays a role in inflammatory and infectious diseases. The modulation of this role by TXA may influence the development of postoperative infectious complications.

Methods

We collected and reviewed the charts of 110 patients who underwent spine surgery at our academic center. We used multivariate regression analysis to assess the factors affecting surgical site infection (SSI).

Results

Of the 110 patients included in this study, 21 patients (19%) were categorized as having postoperative wound complications, 16 patients (14%) had deep or superficial wound infection, and five patients (4%) had wound dehiscence. Patients with a higher surgical invasiveness index score, longer surgeries, and older patients were found to be at risk for wound complications. TXA was determined not to be a direct risk factor for wound healing complications and SSIs.

Conclusions

We found no risk of wound healing complications and SSI directly attributable to preoperative and intraoperative treatment with TXA in spine surgeries.