Spinal surgery complications are still a relevant and unsolved problem. The incidence of complications in spinal surgery literature ranges between 7 and 20% [
1,
2,
7‐
11]. The purpose of this study is to investigate whether the World Health Organization (WHO) Safety Surgical Checklist is an effective tool to reduce complications in spine surgery. In our study population, a reduction in the overall incidence of complications has been observed following the introduction of the WHO Safety Surgical Checklist: In 2010, without the use of the checklist, the incidence of complications was 24.2%, while in 2011 and 2012, following the checklist introduction, the incidence of complications was 16.7% and 11.7%, respectively (mean 14.2%) (
p < 0.0005).
We faced two aspects of spinal surgery complications: (1) the collection and classification; (2) the use of preventive measures to improve safety.
Collection and classification of spinal surgery complications
Nasser et al. [
7] performed a systematic evidence-based review of 105 published studies concerning spinal surgery (84 retrospective, 21 prospective) and found a higher incidence of complications (19.9%) in prospective studies compared with retrospective studies (16.1%). This is secondary to the greater accuracy of record-keeping, the absence of recall bias, and clear definition of complication [
2,
7,
17]. The incidence of complications varied widely in spinal surgery literature, even in prospective studies. Rampersaud et al. [
3] reported an overall incidence of intraoperative adverse events of 14% (98 adverse events in 700 patients), but only 23 adverse events led to postoperative clinical sequelae for an overall intraoperative complication incidence of 3.2%, while Yadla et al. [
2] reported a very high rate of early complications (those occurring within 30 days of surgery): global incidence of 53.2%, with a minor complication incidence of 46.4% and a major complication incidence of 21.3%.
There is no standard definition of complications in spine surgery literature [
3]. Different definitions and classifications of complications by different investigators make difficult to compare studies. The Clavien–Dindo and SAVES capture and grading systems [
25‐
27] divide the severity of surgical complications into levels based on the grade of treatment required to face the complication. Complications were categorized as major or minor by Glassman et al. Significant complications requiring reoperation or leading to permanent deficit were considered major complications. Other general medical adverse events or perioperative events with time-limited effect were considered minor complications [
28].
To date, few studies have evaluated the effect of complication severity on clinical outcomes [
28‐
30]. Glassman et al. analyzed a prospective multicenter database for adult spinal deformity to explore the effects of major and minor complications on 1-year disability, pain, postoperative quality of life and found that major complications, although rare, evidently deteriorated the quality of life [
28]. Fritzell et al. [
29] found no significant differences of effects of major and minor complications on 2-years outcomes in three different types of fusion surgery. Grainger et al. explored the relationship between severity of complications and outcomes in a larger sample of patients following Clavien–Dindo classification of complications and found that the severity of perioperative surgical complications does not appear to influence 1- or 2-year pain and disability outcomes [
30]. Lambat et al. confirmed, through a large retrospective study, that Oswestry Disability Index (ODI) at 2-year follow-up was not statistically different between patients having no complications, minor complications, or major complications. However, if the minimum clinically important difference (MCID) for ODI was analyzed, it resulted statistically significantly smaller in the major complication group (31%) than in the minor complication (51%) and no complication groups (65%;
p < 0.001) [
10], demonstrating an impact of complications on outcome.
Chen et al. recently conducted an interesting experiment. They compared the complications rate among groups of patients undergoing spine, hip, knee, and shoulder surgery; the study was a 10-week prospective study where SAVES V2 and OrthoSAVES were used by six orthopedic surgeons and two independent, non-MD clinical reviewers to record adverse events after all elective procedures. For a spine surgeon, the first important result of this study was the highest rate of complications in the spinal surgery group compared to the other surgeries, but the most important observation of this study was that overall, 99 adverse events were captured by the reviewers, compared with 14 captured by the surgeons (
p < 0.001); surgeons adequately captured major adverse events, but failed to record minor events that were captured by the reviewers; in the spinal surgery group, reviewers captured 45 adverse events versus 8 captured by surgeons [
31].
The study by Chen et al. [
31] confirmed the rate of complications as a problem to be urgently faced in spinal surgery and highlighted the inadequate figure of the surgeon as an evaluator of complications. It seems that spinal surgeons underestimate the complications impact on the patients and health system. As in a football game, the winning team usually maintains the best balance between the offense and defense units; in comparison, surgeons probably represent a really good offense unit (mission), but they lack in defense, where Chen’s reviewers demonstrated to be the better unit in that area (safety). The question to be addressed is what should be the first, mission or safety? We need an independent reviewer team (defense unit) to reduce complications and improve safety, and in doing so, we will probably improve clinical outcomes as well.
In this retrospective study, we observed that the overall incidence of complications in our spine surgery center during 3 years was 17.3%. We divided the complications into seven categories: hematoma, infection, cerebrospinal fluid (CSF) leakage or fistula, mechanical complications, neurological damages, systemic complications, and surgery-related death. This is probably the main weakness of the study: As the collection of complications started using a non-standardized system inserted in the hospital medical charts, any known classification system (as Glassman’s, Clavien–Dindo’s or SAVES systems) was used [
25‐
28]; this probably caused an underestimation of the number of complications captured.
The most frequent complications observed in the current study were wound infections (5.5%), mechanical complications (4.4%), and neurological damages (3.2%). In our study population, almost 95% of the patients were affected by oncologic and degenerative diseases; we observed a trend to a higher wound infection complications (7.4%) in oncologic patients, while a trend to a higher rate of mechanical complications (5.8%) was observed in patients with degenerative diseases, even in the absence of statistical difference (p = 0.12).
This study found no correlation between diagnosis and overall complications’ incidence (
p = 0.48). This was different from other large-scale studies which report a higher incidence of complications in patients undergoing surgery for oncological pathologies [
8,
9,
32,
33]. This could be mainly due to the long experience of the authors in tumor spinal surgery [
34‐
36].
This study found a rate of early complications (arising within 1 month after surgery) of 43.3%, a rate of complications requiring surgical revision of 7.6%, and a rate of neurological sequelae causing permanent damage of 2.4%. These types of complications have a relevant impact on the health system and, especially, the last two categories on the patients’ quality of life and clinical outcomes.
Preventive measures to improve safety: the WHO Surgical Safety Checklist
Considering the high incidence of complications in spine surgery, during the last years several authors focused their attention on the risk factors related to the onset of complications and on predictive models of complications after spine surgery [
12‐
16].
Moreover, several preventive measures have been studied and recently described in order to reduce complications in spine surgery, concerning intraoperative neuromonitoring, blood loss reduction, and infections and thrombosis prophylaxis [
19‐
23]. Sethi et al. [
24] reported their experience concerning the application of Lean methodology in orthopedic surgery and specifically in spine surgery. Lean methodology was developed in the manufacturing industry to increase output and decrease costs, and then, it was implemented in many areas of health care. The authors described a step-by-step process designed specifically to optimize and standardize preoperative, intraoperative, and postoperative care for patients undergoing complex spine surgery, and they reported a significant reduction in overall complication rate [
24].
In 2009, Haynes et al. [
18] developed a 19-item Surgical Safety Checklist (SSC) to improve intraoperative outcomes and minimize preventable complications, thus making the culture of the operating theater safer, more communicative, and more collaborative. This checklist derived from an implementation of the Surgical Safety Checklist elaborated by WHO in 2008.
Although several investigators have challenged the efficacy of the SSC, it has shown repeated success in reducing preventable postoperative complications, length of hospital stay, and overall mortality [
18,
37‐
39]. In addition, multiple investigators have concluded that the implementation of the SSC in multiple institutions has improved communication, efficiency, and attention to routine details in the operating room.
In the present study, we investigated, as preventive measure to reduce complications in spinal surgery, the introduction of the WHO Safety Surgical Checklist. Results showed a reduction in the overall incidence of complications following the introduction of the WHO Safety Surgical Checklist: In 2010, without the use of the checklist, the incidence of complications was 24.2%, while in 2011 and 2012, following the checklist introduction, the incidence of complications was 16.7% and 11.7%, respectively (mean 14.2%) (p < 0.0005). From our knowledge, this is the first report about the application of the WHO Surgical Safety Checklist in spinal surgery.
The only other reason that may have cooperated in the reduction in postoperative infections rate was the introduction in our institute of a new internal guideline for the prevention of infections in spine surgery (dated 07/20/2010) which has slightly changed the type of antibiotic drugs used for prophylaxis (one modified drug among five drugs used). However, the trend to the reduction in overall complications can be attributed to the introduction of the WHO checklist. In our experience, most of the alerts highlighted by the WHO checklist were really useful to do the right action in the right moment to avoid complication; in particular the questions contained in the Time Out section: Surgeon reviews: “What are the critical or unexpected steps, operative duration, anticipated blood loss?” and Anaesthesia team reviews: “Are there any patient-specific concerns?”improved the surgical team interactions and led to changes in surgical and anesthesiological procedures during the intervention that really allowed to avoid complications. The other question contained in Time Out section “Nursing team reviews: has sterility (including indicator results) been confirmed? Are there equipment issues or any concerns?” allowed to discover, before the beginning of the intervention, contaminated implants or surgical devices, skipped from the previous control, and led to avoidance of postoperative infections and other mechanical complications.
This study presents some limitations. First, it is a retrospective study where a non-standardized system was used for capturing the complications; therefore, complications can be incorrectly estimated. Second, our department performed spinal surgery mainly for oncological and degenerative diseases. Infection and trauma surgery occupied only a small proportion. Hence, the current study population cannot represent the generally common spinal surgery population, and this could lead to a certain degree of bias in the results of the present study. In particular, the incidence of late complications (i.e., mechanical complications and wound infections) could be underestimated in the group of oncologic patients due to their shorter survival compared to the other groups of spine diseases. However, the baseline distribution of the preoperative diagnosis categories had about the same proportion over time, and late complications normally impact on the non-oncologic group of patients, who represent the 45.58% of the study population. Third, the two groups compared were non-homogeneous in terms of patients’ number; patients treated in 2010 without the use of the WHO checklist were only 285, while patients treated in 2011 and 2012 with the use of the WHO checklist were 632.
Despite the aforementioned limitations, the WHO Surgical Safety Checklist resulted to be effective in reducing complications in our center. We think that a system, based on the Surgical Safety Checklist, should be introduced also during the preoperative and postoperative phases, in order to highlight all the specific moments where complication risk factors arise also in these phases. The checklist should be adapted for the specific spinal surgery characteristics. Finally, the introduction and validation of this checklist, implemented for preoperative, intraoperative, and postoperative phases, should be followed by the identification of targeted actions to prevent complications and improve patients’ safety.