The potential complications encountered during spinal surgery are varied and can occur during both the intraoperative and the postoperative period. Although strategies are used to decrease the risk of these potential complications, the majority are not preventable. For example, it is unrealistic to think that the risk of infection will ever be eliminated, despite sterile technique and antibiotics used during the perioperative period. It is unrealistic to think the risk of deep venous thrombosis will ever be eliminated, despite the use of mechanical DVT prophylaxis and early mobilization. On the contrary, wrong level or wrong side surgery may be preventable.
The JC defines wrong site surgery as any surgery performed on the wrong site or patient or performance of the wrong procedure.1 Wrong site surgery is a broad term that encompasses all surgical procedures performed on the wrong body part or wrong patient. The following are more specific descriptions of wrong site surgery.2 Wrong level or part surgery is a surgical procedure performed at the correct site but at the wrong level or part of the operative field. For example, performing a lumbar laminectomy on an unintended intervertebral level immediately adjacent to an intervertebral level with identified pathology can be considered as wrong level or part surgery. Wrong patient surgery is a misidentification of the patient leading to a procedure performed on the wrong patient. Wrong side surgery is a surgical procedure that involves operating on the wrong extremity or wrong side of the body. Wrong level exposure occurs when a level other than the intended level of surgery is exposed; however, it does not necessarily mean that surgery was performed at the incorrect level (Table 1).
From 1995 to 2005, the JC sentinel event statistics database ranked wrong site surgery as the second most frequently reported event with 455 of 3548 sentinel events (12.8%). Although the event seems to be rare, the incidence of these complications has been difficult to measure and quantify. The implications for wrong site surgery go beyond the effects to the patient. Such an event has profound medical, legal, social, and emotional implications.3 The American Academy of Orthopedic Surgeons first addressed the issue in an advisory statement issued in 1997, recommending that surgeons put their initials on the operation site.4 The North American Spine Society (NASS) developed the “Sign, Mark and Radiograph” program in 2001, consisting of a checklist for patient safety.5 In 2003, the JC promoted the “Universal Protocol for Preventing Wrong Site, Wrong Procedure, Wrong Person Surgery.”6 Since July 2004, all accredited hospitals are required to implement this protocol.7 NASS guidelines are mostly consistent with JC guidelines. Both require the surgeon to perform an intraoperative radiograph; however, NASS mandates that personal marking of the surgical site be performed by the primary surgeon where JC does not specify who should do this.8 Many experts have speculated about the factors that contribute to wrong site surgery. The JC has examined all the cases submitted through their sentinel event reporting system and have identified factors that they feel contributed to this event. Based on these contributing factors, the JC has also established preventative measures that they recommend be employed for all surgeries.
The following questions determined the focus of this systematic review:
- What is the incidence or frequency of wrong site surgery?
- What are the causes of wrong site surgery?
- What preoperative measures are effective in preventing wrong site surgery?
Materials and Methods
Electronic Literature Database
The literature search is outlined in detail elsewhere.8a Briefly, a systematic search was conducted in MEDLINE, EMBASE, the Cochrane Collaboration Library, and the Food and Drug Administration and JC websites for literature published from 1990 through December 2008. We limited our results to humans and to articles published in the English language. Reference lists of key articles were also systematically checked. For our first study question, we attempted to identify the studies specifically designed to evaluate the incidence or frequency of wrong site surgery. Our primary focus was to identify the spine studies but we included other surgical reports if they contributed to answering our objectives because the literature was limited on this topic. To determine the causes of wrong site surgery (study question 2), we attempted to identify the studies that specifically evaluated the risk factors for this event. To determine effective preventative measures (study question 3) we attempted to identify the studies that measured the effect of an intervention or prevention strategy. For this objective, we were interested in studies that compared wrong site rates between those who implemented prevention strategies with those where no such strategy was used. If such studies were not identified, we relied on credible organizations such as the JC to offer these answers. Exclusions included editorials, review articles without quantitative data, case reports, and non-English written studies, Figure 1.
Each retrieved citation was reviewed by two independently working reviewers (D.C.N. and J.R.D.). Most articles were excluded on the basis of information provided by the title or abstract. Citations that appeared to be appropriate or those that could not be excluded unequivocally from the title and abstract were identified, and the corresponding full text reports were reviewed by the two reviewers. Any disagreement between them was resolved by consensus. From the included articles, the following data were extracted: diagnosis, surgical treatment, rate or number of documented events of wrong site surgery, risk factors, and preventative measures (if reported).
Level of evidence ratings were assigned to each article independently by two reviewers using criteria set by The Journal of Bone and Joint Surgery, American Volume (J Bone Joint Surg Am)9 for prognostic studies and therapeutic studies and modified to delineate criteria associated with methodologic quality and described elsewhere (See Supplemental Digital Content, Table 1, available at: http://links.lww.com/BRS/A418).
The incidence of wrong site surgery could not be calculated in any study, because this measure requires an accurate count of events, number of patients at risk, and defined time period. A rate (events divided by number of surgeries) of wrong site surgery could be calculated in several studies using various study methods.7,8,10–12 The remaining studies reported frequencies or proportions of events among all adverse events reported (not among all subjects at risk); therefore, a rate could not be calculated. Study methods and definitions of wrong site surgery were so different that a pooled rate calculation was not possible. Data were summarized in tables, and qualitative analysis13 was performed considering the following three domains: quality of studies (level of evidence), quantity of studies (the number of published studies similar in patient population, condition treated, and outcome assessed), and consistency of results across studies (whether the results of the different studies lead to a similar conclusion).14 We judged whether the body of literature represented a minimum standard for each of the three domains using the following criteria: for study quality, at least 80% of the studies reported needed to be rated as a level of evidence I or II; for study quantity, at least three published studies were needed, which were adequately powered to answer the study question; for study consistency, at least 70% of the studies had to have consistent results. The overall strength of the body of literature was expressed in terms of the impact that further research may have on the results. An overall strength of “high” means that further research is very unlikely to change our confidence in the estimate of effect. The overall strength of “moderate” is interpreted as further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. A grade of “low” means that further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate, whereas “very low” means that any estimate of effect is very uncertain.8a
We identified 65 articles or reports from our literature search reporting on wrong site surgery. From these potential articles or reports, we judged 19 to undergo full text review. After full text review, we excluded eight for the following reasons: four articles did not report any count or frequency data, three articles were review articles without quantitative data, and one article reported on patient compliance but did not report wrong site events (Figure 2). Table 2 summarizes studies reporting a rate (number of events divided by number of surgeries) of wrong site surgery, and Table 3 summarizes studies reporting frequencies or proportion of wrong site surgeries among all adverse events.
What Is the Incidence or Frequency of Wrong Site Surgery?
Five studies were identified that reported a rate of wrong site surgery (Table 2.) In a prospective case series by Ammerman et al, 100 patients were treated with lumbar discectomy. Despite no wrong site surgeries being performed, there was a 15% rate of wrong level exposure. Side, sex, weight, and transition level were not significantly associated with wrong level exposure. Kwaan et al7 reported a rate of 1 in 112,994 surgeries evaluating data from hospitals and a malpractice insurer. Twenty-five nonspine and 15 spine wrong site surgical events were reported. Jhawar et al, Mody et al, and Meinberg and Stern conducted surveys on 194, 415, and 1560 neurosurgeons, spine surgeons, and general/orthopedic/plastic surgeons, respectively.8,11,12 The response rate in the study by Jhawar et al was 75%, and completion rate was 68%. Surgeons were asked to report their experience on cervical and lumbar discectomies and craniotomies. The reported rate of wrong site surgery was 4.5, 6.8, and 2.2 per 10,000 for all operations, discectomies, and craniotomies, respectively. Mody et al had a response rate of 12%. Surgeons reported a wrong site surgery rate of one for every 3110 procedures. Fifteen percent reported preparing a wrong spine level before incision at least once and 50% reported one or more wrong level surgeries in their career in the lumbar (71%), cervical (21%), and thoracic (8%) regions. Seventeen percent of these resulted in a legal action or a monetary settlement. Meinberg and Stern had a response rate of 67%. Surgeons reported a wrong site surgery rate of 1 in 27,686 procedures. Sixteen percent reported preparing the wrong site, but noticed the error before the incision; 21% reported performing wrong site surgery at least once. The most common wrong site surgeries were the fingers (63%), wrist (9%), and hand (8%).
Six studies reported a frequency of wrong site surgeries as a proportion of overall adverse events (Table 3). Clarke et al reported 427 wrong site surgeries of 433,528 reports to the Pennsylvania Patient Safety Reporting System. Fifty-six percent were near misses, 70% were wrong-side surgeries, 14% wrong location/level surgeries, 9% were wrong procedures, and 8% were performed on the wrong patient. Seiden et al15 evaluated four different databases in the state of Florida. Based on their data, this group estimated that 1300 to 2700 wrong site surgeries are performed annually in the United States. They identified the knee as the most common site (37%). Laminectomy and craniotomy comprised 2% each of the wrong site surgeries. These authors concluded that wrong side/wrong site, wrong procedure, and wrong patient adverse events, although rare, are more common than healthcare providers and patients appreciate. Goodkin et al analyzed data from a collection of lawsuit outcomes published in a national monthly newsletter of malpractice cases from various spine surgeries. The majority of unintended surgeries were performed at the wrong level in the lumbar spine. Intended L5-S1 procedures operated on at the L4-L5 level were the most common. Sixty eight (99%) of cases went to litigation, and 37 (54%) settled out of court with indemnity ranging from $62,000 to $1,500,000. The two JC reports were not designed to establish incidence as only sentinel events were reported to the system. The majority of the events were a result of orthopedic procedures in the 1998 (67%) and 2001 (41%) reports. Neurosurgical procedures represented 13% and 14% of reports, respectively. The remaining studies involved various surgical procedures. The Minnesota Department of Health has a mandatory reporting system for serious adverse events including surgical adverse events.16 Wrong site surgery, wrong patient, and wrong procedure made up 24% (n = 150) of all reported adverse events over a 5-year period. During a 4-year period, 14% of surgical wrong site events occurred in spine surgeries.
In summary, the estimated rate of wrong site surgery varies widely ranging from 0.09 to 4.5 per 10,000 surgeries performed (Table 4). Many studies do not allow for the calculation of an event rate.
What Are the Causes of Wrong Site Surgery?
Risk factors for wrong site surgery were also reported in these studies quantifying frequency (Tables 2 and 3). The study by Ammerman et al evaluating lumbar discectomy found pathology above the L5-S1 level (P = 0.004), and patients older than 55 (P = 0.04) were significantly associated with wrong level exposure.10 Side, sex, weight, and transition level were not found to be significantly associated with wrong level exposure. The self report survey study by Mody et al12 found increased surgeon age (P = 0.024) and a longer duration of practice (P = 0.025) significantly associated with wrong site surgery. However, the annual risk demonstrated a significant decrease with an increase in duration of practice (P < 0.001). Surgeons with higher annual surgical loads and surgeons in academic versus private practice settings were not found to be significantly associated with wrong site surgery (P = 0.22 and 0.29, respectively). Kwaan et al7 were able to review 13 nonspine cases in detail and found that wrong site surgeries were attributed to errors in operating room scheduling (n = 4), multiple lesions that were not identified, clarified, or documented in the clinic visit (n = 3), incorrectly printed magnetic resonance image (n = 1), and clinic note and consent form specifying incorrect site (n = 1). The others were not specified. Four of the 13 cases were judged to have been preventable by review of radiologic films or reports; in two of these cases, radiologic findings were not available in the operating room.
The remaining studies list contributing factors based on self-report or self documentation by authors submitting the individual reports. Dozens of factors were reported and listed in Tables 2 and 3. The root cause analysis in the 1998 JC report for wrong site surgery reported that most are related to communication, preoperative assessment of patient, and procedures used to verify operative site. Communication falls into these two categories: (1) failure to engage patient (or family) in process of identifying correct surgical site and (2) incomplete or inaccurate communication among members of the surgical team. The 2001 report listed a breakdown in communication between surgical team members and patient/family as the root cause of wrong site surgery. The Minnesota Department of Health root cause analysis in 2006 report the following as causes for all adverse events (wrong site being one of them): communication (53%), training (43%), fatigue/scheduling (10%), environment/equipment (44%), rules/policies/procedures (58%), and barriers (20%).
In summary, contributing factors to wrong site surgery include incorrect patient positioning or preparation of operative site, patient or family providing incorrect information, incorrect or lack of patient consent, failure to use site markings, surgeon fatigue, multiple surgeons, multiple procedures on same patient, unusual time pressures, emergent operations, unusual patient anatomy, and overall poor communication (Table 4).
What Preoperative Measures Are Effective in Preventing Wrong Site Surgery?
In the only study identified in the literature assessing preventative strategies for wrong site surgery, Kwaan et al7 reviewed all wrong site surgeries to determine whether the Universal Protocol published by the JC in 2003 would have prevented these events. The Universal Protocol emphasizes three minimum requirements: preoperative verification, site marking, and a “time out” in the operating room. Thirteen of the nonspine cases were reviewed in detail. For 5 of the 13 cases (38%), the authors judged it unlikely that the Universal Protocol would have prevented them. The authors concluded that current site-verification protocols could have prevented only two of three of examined cases and that many protocols involve considerable complexity without clear added benefit. It is important to note that this study did not compare wrong site events in patients where the Universal Protocol was applied compared with those where it was not applied. This was a retrospective assessment based on the authors' judgment of whether the protocol would have been effective.
No other studies have been performed to evaluate preventative strategies. Giles et al17 reported that most surgeons have experienced wrong site surgery with no specific risk factors or causes identified. Marking practices and the method for marking varied considerably. Orthopedic surgeons reported that they always mark while other surgical specialties never mark or mark occasionally. This group concludes that standardization of marking practices has potential advantages but admit that some resistance may exist against a standard policy on preventing wrong site surgery; however, given that surgeons often work across multiple sites, a standard policy on preventing wrong site surgery may become necessary in the United Kingdom.
Gibbs18 admit that not enough time has passed since the introduction of the Universal Protocol to determine its effectiveness in decreasing the incidence of wrong site surgery but it has brought about the changes in the way invasive procedures are planned and started and has influenced the way team members communicate with each other. Both JC and NASS have provided guidance on strategies for preventing wrong site surgery (Supplemental Digital Content, Tables 2 and 3 respectively, available at: http://links.lww.com/BRS/A418). Wong and Watters reported wrong site surgery statistics before and after implementation of the JC Universal Protocol. After a full year's statistics had been accumulated, it was found that wrong site surgery events had actually increased by 88 comparing 2005 to 2004.19 Overall wrong site surgery had moved from the number three to the number two ranking in frequency of Sentinel Events (behind inpatient suicide). The authors appropriately considered whether these data represent a true increase in the frequency of wrong site surgery or are better explained by an increased awareness and reporting. This is unclear using these methods.
In summary, there is no evidence to support the JC checklist, NASS checklist, or other preventative measures with respect to their effectiveness in preventing a wrong site surgery.
The overall strength of the evidence to establish an incidence or rate of wrong site surgery is “very low,” that is, any estimate of effect is very uncertain (Table 5). The overall strength of the evidence to establish the causes of wrong site surgery is “low,” that is, further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. The overall strength of the evidence to establish the efficacy of preoperative measures including checklists for preventing wrong site surgery is “very low.”
The purposes of this literature review were to determine the incidence of wrong site surgery, determine the causes of wrong site surgery, and determine what preoperative measures are effective in preventing wrong site surgery. The literature available does not clearly define the incidence of wrong level or wrong site surgery as it pertains to spinal surgery. It does reveal that this preventable complication occurs. Ammerman et al reported a 15% rate of wrong level exposure in a prospective study of 100 discectomies. Although this does not likely reflect the national or worldwide incidence of this complication, it highlights the conclusions made by Seiden and Barach that these complications are probably underreported and more common than we appreciate.
Because of the paucity of reports on wrong site events, few evaluations have been performed looking at the association between risk factors and wrong site surgery. The causes of wrong site surgery have been based mostly on surgeon reports when a wrong site event occurs. Incorrect patient positioning or preparation of the operative site, patient or family providing incorrect information, incorrect or lack of patient consent, failure to use site markings, surgeon fatigue, multiple surgeons, multiple procedures on same patient, unusual time pressures, emergent operations, and unusual patient anatomy are consistently reported. Both published JC reports acknowledge a breakdown in communication between surgical team members and patient/family as the root cause of wrong site surgery. Analytical studies evaluating risk factors for wrong site surgery during discectomy have identified pathology above L5-S1 and patients older than 55 years.10 Self-reported surveys looking at risk factors among surgeons have identified surgeon age and a longer duration of practice as significantly associated with wrong site surgery.17 There were no significant differences between academic versus private practice setting. It is not surprising to the casual observer that the aforementioned contributing factors are the root causes for many wrong site or wrong level adverse events. In the era of decreasing reimbursements, the drive to do more in less time has streamlined many practices during the perioperative period. The consent form is not always produced by the primary surgeon. The surgeon using two operating suites may not be present during patient positioning. The encounter with the patient and family in the preoperative holding area may be performed by someone other than the primary surgeon. This can lead to the additional variables that result in the breakdown in communication highlighted by the 1998 JC report.
Only one study in the literature evaluated prevention strategies for wrong site surgery. Kwaan et al7 evaluated the Universal Protocol published by the JC in 2003. Despite its ability to prevent the majority of these events, this report concluded that current site-verification protocols could have prevented only two of three of examined cases. The Universal Protocol has brought about changes in the way invasive procedures are planned and started, and has influenced the way team members communicate with each other. Both JC and NASS have provided guidance on strategies for preventing wrong site surgery (Supplemental Digital Content, Tables 2 and 3, respectively, available at: http://links.lww.com/BRS/A418). It is important to note that there is no evidence to support these procedures with respect to their effectiveness in reporting a wrong site surgery. Although site marking is probably a very effective method for avoiding wrong site surgery involving the extremities, it is less useful as it pertains to spine surgery unless a unilateral procedure is planned, such as a lumbar discectomy for a right-sided paracentral L4-L5 herniated nucleus pulposus. Site marking provides no effective measure in avoiding wrong level surgery. Nassr et al19a recently reported a 17% rate of incorrect needle localization during anterior cervical surgery using the needle puncture technique as the method for marking the spinal level. This clearly defines the need for intraoperative imaging to evaluate for the correct level. Only intraoperative imaging, either using standard radiographic imaging or fluoroscopic imaging, while marking the level with a surgical instrument, can verify the correct level.
This systematic review has limitations based primarily on the lack of quality and quantity research in this area. It is probably not feasible to perform a prospective, randomized trial to generate level I evidence that these procedures, among others as outlined by JC and NASS, are effective in decreasing the incidence of these adverse events. As Gibbs has pointed out that continued adherence to the Universal Protocol guidelines over a longer period of time is probably required before a decrease in incidence can be measured.
Despite the low level of evidence, we suggest that the NASS and JC checklists are insufficient on their own to minimize this complication. In addition to these protocols, we, therefore, recommend intraoperative imaging after exposure and marking of a fixed anatomic structure. This imaging should be compared with routine preoperative studies to determine the correct site for spine surgery.
- Wrong site and wrong level surgery may be preventable.
- Estimated rate of wrong site surgery varies widely ranging from 0.09 to 4.5 per 10,000 surgeries performed.
- There is no literature to substantiate the effectiveness of the current Joint Commission (JC) Universal Protocol in decreasing the rate of wrong site, wrong level surgery.
- In addition to the JC Universal Protocol, intraoperative imaging following exposure and marking of a fixed anatomic structure should be used to determine the correct level for spine surgery.
Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.spinejournal.com).
The authors thank Ms. Nancy Holmes, RN, for her administrative assistance, and Jeff Hermsmeyer for his assistance in searching the literature, abstracting data, and proofing.
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