Lumbar fusion is a relatively common spine proce-dure, accounting for over 400,000 procedures an-nually.9,35 In addition, there was an approximate
15-fold increase in the number of lumbar instrumentation procedures performed from 2002 to 2007.9 As the number of spinal fusion procedures increases, the number of com-plications is also expected to rise.9 One of these compli-cations is spinal infection.9 Postoperative spinal infection occurs in approximately 1%–5% of patients undergoing spine surgery.5,13,28 This risk is highest in patients under-going posterior approaches, lumbar surgery, and of instru-mentation-augmented procedures.5,13,28 Patients in whom
infections develop typically have worse pain-related out-comes, increased deformity, higher medical costs, and longer hospital stays.5,13,28 The ability to identify patients with the greatest risk of developing postoperative spinal infections may therefore lead to more selective ways of minimizing infection.
Studies on postoperative spinal infections following instrumented lumbar fusion surgery are few and limited (Table 1).11,29,30,45,46 These previous studies confound the true incidence of infections for posterior lumbar instru-mented fusion because they include patients with different pathological entities such as tumors and trauma,6,36 pa-tients who underwent nonlumbar procedures,22,34 and pa-tients who did not undergo instrumented fusion.12,30 There-
Risk of infection following posterior instrumented lumbar fusion for degenerative spine disease in 817 consecutive cases
Clinical article
Kaisorn L. ChaiChana, M.D., MohaMaD ByDon, M.D., DaviD r. santiago-Dieppa, M.D., Lee hwang, M.D., gregory MCLoughLin, M.D., DanieL M. sCiuBBa, M.D., Jean-pauL woLinsKy, M.D., aLi ByDon, M.D., Ziya L. goKasLan, M.D., anD tiMothy withaM, M.D.Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
Object. Posterior lumbar spinal fusion for degenerative spine disease is a common procedure, and its use is in-creasing annually. The rate of infection, as well as the factors associated with an increased risk of infection, remains unclear for this patient population. A better understanding of these features may help guide treatment strategies aimed at minimizing infection for this relatively common procedure. The authors’ goals were therefore to ascertain the incidence of postoperative spinal infections and identify factors associated with postoperative spinal infections.
Methods. Data obtained in adult patients who underwent instrumented posterior lumbar fusion for degenerative spine disease between 1993 and 2010 were retrospectively reviewed. Stepwise multivariate proportional hazards regression analysis was used to identify factors associated with infection. Variables with p < 0.05 were considered statistically significant.
Results. During the study period, 817 consecutive patients underwent lumbar fusion for degenerative spine dis-ease, and 37 patients (4.5%) developed postoperative spine infection at a median of 0.6 months (IQR 0.3–0.9). The factors independently associated with an increased risk of infection were increasing age (RR 1.004 [95% CI 1.001–1.009], p = 0.049), diabetes (RR 5.583 [95% CI 1.322–19.737], p = 0.02), obesity (RR 6.216 [95% CI 1.832–9.338], p = 0.005), previous spine surgery (RR 2.994 [95% CI 1.263–9.346], p = 0.009), and increasing duration of hospital stay (RR 1.155 [95% CI 1.076–1.230], p = 0.003). Of the 37 patients in whom infection developed, 21 (57%) required operative intervention but only 3 (8%) required instrumentation removal as part of their infection management.
Conclusions. This study identifies that several factors—older age, diabetes, obesity, prior spine surgery, and length of hospital stay—were each independently associated with an increased risk of developing infection among patients undergoing instrumented lumbar fusion for degenerative spine disease. The overwhelming majority of these patients were treated effectively without hardware removal.(http://thejns.org/doi/abs/10.3171/2013.10.SPINE1364)
Key worDs • degenerative • decompression • fusion • infection • instrumentation • lumbar spine • risks • spinal surgery
Abbreviation used in this paper: IQR = interquartile range.
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fore, it is difficult to interpret the risk of spinal infection for patients who are undergoing posterior lumbar fusion for degenerative spine disease, which is the most common type of fusion procedure.9,35 The goals of this study were therefore: 1) to ascertain the incidence of postoperative spinal infection among patients undergoing posterior lum-bar fusion for degenerative spine disease, and 2) to iden-tify the factors associated with an increased risk of spine infection in this patient population.
MethodsPatient Selection
All adult patients (age > 18 years) who underwent spinal surgery from 1993 to 2010 in the neurosurgery department at a single tertiary care institution were retro-spectively identified and data were reviewed from a pro-spectively collected database by clinicians blinded to pa-
tient outcomes. Patients who underwent posterior lumbar instrumented fusion for degenerative spine disease were included. Patients who underwent surgery for trauma, tu-mor, infection, and/or vascular disorder were excluded. Additionally, patients who underwent cervical and/or thoracic fusions not involving the lumbar spine were not included. Likewise, patients who underwent anterior ap-proaches and/or noninstrumented fusion, including in situ fusion, were excluded. These exclusions were done to cre-ate a more uniform population of patients with degenera-tive spine disease who underwent instrumented posterior lumbar fusion.Recorded Variables
Eight hundred seventeen consecutive patients met the inclusion criteria. The neurosurgery clinical, opera-tive, and postoperative notes for all patients who met the inclusion criteria were retrospectively reviewed by clini-
TABLE 1: Previous studies evaluating the incidence and risk factors of postoperative spine infection following instrumentation of the lumbar spine in a noninfected patient population
Authors & Year No. of Patients No. of Infections
Study IncludedMultivariate Analyses
Noninstrumented Patients
Diffuse Pathology
Nonlumbar Patients
present study 817 37 no no no yesAbdul-Jabbar et al., 2012 6628 193 yes yes yes yesAhn et al., 2012 3457 384 no yes no noKurtz et al., 2012* 15,069 1280 no yes no yesMehta et al., 2012 298 24 no yes no yesPetilon et al., 2012 60 30 no yes no noAleissa et al., 2011 227 13 no yes no yesFalavigna et al., 2011 13 13 no yes yes noKoutsoumbelis et al., 2011 3218 84 no no no yesMcGirt et al., 2011* 5170 292 no yes no noSmith et al., 2011* 108,419 2277 no yes no yesSchimmel et al., 2010 171 36 yes yes yes yesSchwarzkopf et al., 2010 132 61 yes yes yes noChen et al., 2009 195 27 no yes no yesMaragakis et al., 2009 208 104 yes yes yes noO’Toole et al., 2009 1338 3 yes yes yes noPull ter Gunne et al., 2010 3174 132 yes yes yes yesOlsen et al., 2008 2316 46 yes yes yes yesRihn et al., 2008 236 7 no yes yes noFriedman et al., 2007 123 41 yes yes yes noFang et al., 2005 1095 48 yes yes yes noBlam et al., 2003 256 24 yes yes yes yesOlsen et al., 2003 219 41 yes yes yes yesRechtine et al., 2001 235 12 no yes yes noSponseller et al., 2000 210 25 no yes yes noWeinstein et al., 2000 2391 46 yes yes yes yesWimmer et al., 1998 850 22 yes yes yes yesLevi et al., 1997 452 17 no yes yes noGlassman et al., 1996 858 22 no yes no no
* Population-based database.
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cians. The information collected included patient demo-graphics, comorbidities, previous surgeries, surgical lev-els, fused levels, decompressed levels, presence of a CSF leak, length of hospital stay, perioperative complications, wound infections, and antibiotic regimen. Severe obesity was defined as a body mass index greater than 35. Lesser degrees of obesity were not routinely recorded. The pres-ence of a wound infection was identified based on postop-erative clinical notes, using the CDC definition of infec-tion.21 This was done, instead of using ICD-9 codes, to make sure all infections (both operative and nonoperative) were captured.
General Treatment StrategyInstrumented fusion was generally pursued for pa-
tients with degenerative spine disease when they had clinical and/or radiographic signs of instability or were at risk for iatrogenic instability. Patients typically underwent medical evaluation prior to surgery, which allowed a more comprehensive inclusion of patient comorbidities. Prior to incision, the surgical area was typically cleaned with Betadine or chlorhexidine scrub followed by application of Betadine or chlorhexidine solution. Intravenous anti-biotics were typically administered within 30 minutes of skin incision. Cefazolin (2 mg) was typically given, unless the patient had an allergy to penicillin-based drugs, and then clindamycin (500 mg) was given instead; it was then was typically given again every 4 hours, and clindamycin every 8 hours. Surgical drains were typically placed and were removed when drainage was less than 50 ml/day. Antibiotics were either given for 24 hours after surgery or until drains were removed. The choice of hardware for in-strumented fusion was based on the surgeon’s preference. All hardware used after 2000 was titanium based.
Patients in whom an infection was suspected typi-cally underwent MRI of the spine with and without Gd, as well as complete blood count, erythrocyte sedimentation rate, and C-reactive protein tests. An infectious disease team was involved in the care of these patients. The choice and duration of antibiotics was made by the infectious disease team and was determined by the culture sensi-tivities. The decision to preserve or remove the implanted hardware was made based on surgeon preference and the recommendations made by the infectious disease consul-tant. However, starting in 2002, an attempt to preserve the hardware was made in all cases.
Statistical AnalysisSummary data were presented as the mean ± SD and
the median (interquartile range) for parametric and non-parametric data, respectively. Stepwise multivariate pro-portional hazards regression analysis was used to identify independent factors associated with developing a wound infection. In this analysis, univariate analyses were first performed to identify potential factors associated with in-fection. Factors with p < 0.10 were included in a stepwise multivariate proportional hazards regression analysis, and values with p < 0.05 were considered statistically signifi-cant. JMP v9 software (SAS) was used unless otherwise specified.
ResultsPreoperative and Perioperative Characteristics
Eight hundred seventeen consecutive patients under-went instrumented lumbar fusion during the period under review (Table 2). The average age of the patients was 56 ± 14 years, and 373 (46%) were male. Prior to surgery, 90 patients (11%) had diabetes, 102 (12%) had coronary artery disease, 82 (10%) were severely obese, 15 (2%) had chronic obstructive pulmonary disease, 11 (1%) had sleep apnea, 16 (2%) had atrial fibrillation, and 164 (20%) were smokers. Previous spine surgery had been performed in 329 patients (40%).
The perioperative characteristics are summarized in Table 2. The median numbers of surgical levels, fused lev-els, and decompressed levels were 3 (IQR 2–4), 3 (IQR 2–3), and 2 (IQR 1–3), respectively. A CSF leak occurred in 10 patients (1%). The median hospital stay was 5 days (IQR 3–6 days). Perioperatively, 16 patients (2%) had a urinary tract infection, 4 (0.5%) developed pneumonia, 1 (0.1%) had sepsis, and 9 (1%) suffered a deep vein throm-bosis or pulmonary embolism. Thirty-five patients (4%) were lost to follow-up, but none of the patients with infec-tions were lost to follow-up.
Postoperative InfectionAt a median follow-up of 12 months (IQR 3–24
months), 37 patients (4.5%) developed a wound infection. Of these 37 patients, 18 (49%) developed an infection lim-ited to the suprafascial compartment, while 19 (51%) had an infection below the fascia. The postoperative infection was diagnosed at a median of 0.6 months (IQR 0.3–0.9 months). Twenty-one patients (57%) returned to the op-erating room for incision, drainage, and/or debridement of the infection, and 3 (8%) had their hardware removed as part of the infection management. Of these 3 cases of hardware removal, 1 was due to presumed infected hard-ware and 2 were due to hardware loosening in the pres-ence of infection. Surgery was more commonly pursued when infections were subfascial compared to suprafasical (84% vs 28%, p = 0.0008). Of the patients who returned to the operating room, only 1 (5%) required 2 washouts to eradicate the infection, while the remaining patients (95%) only required 1 washout. Primary closure of the wound infection was pursued in 17 patients (81%), and negative–pressure wound therapy (that is, wound VAC [vacuum-assisted closure]) was used in 3 patients (14%).
Twenty-two patients (59%) had Staphylococcus in-fection, 7 (19%) Enterococcus, 4 (11%) Klebsiella, 2 (5%) Pseudomonas, 2 (5%) Corynebacterium, 1 (3%) Esch-erichia coli, 1 (3%) Proteus, and 8 (22%) polymicrobial, and in 8 (22%) no organism was found (18 [49%] patients had more than 1 organism that was cultured from their wound). Twenty-seven patients (73%) received intrave-nous antibiotics for a median duration of 1.5 months (IQR 0.7–1.5 months), while 15 (41%) received oral antibiotics for a median duration of 0.7 months (IQR 0.5–1.3 months). Of these patients who received antibiotic therapy, 7 (19%) underwent oral and intravenous concomitant therapy and 2 (5%) received oral antibiotics after intravenous antibiot-
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ics. No patients required lifelong or long-term (> 6 months) suppressive antibiotics. At a median follow-up time of 12 months (IQR 5–27 months), no patients (0%) had signs of recurrent infection based on CBC, ESR, and CRP.
Factors Associated With Spinal InfectionIn univariate proportional hazards regression analy-
sis, the factors associated with postoperative infection were age, duration of hospital stay, diabetes mellitus, obe-sity, atrial fibrillation, prior surgery, number of surgically treated levels, number of fused levels, perioperative uri-nary tract infection, and CSF leak. No other clinical fac-
tors were associated with postoperative infection includ-ing smoking and number of decompressed levels.
In stepwise multivariate proportional hazards regres-sion analysis (Table 3), the factors that remained signifi-cantly associated with an increased risk of infection were increasing age (RR 1.004 [95% CI 1.001–1.009], p = 0.049), diabetes mellitus (RR 5.583 [95% CI 1.322–19.737], p = 0.02), obesity (RR 6.216 [95% CI 1.832–9.338], p = 0.005), previous spine surgery (RR 2.994 [95% CI 1.263–9.346], p = 0.009), and increasing duration of hospital stay (RR 1.155 [95% CI 1.076–1.230], p = 0.003). In separate analy-ses, the age, number of previous spinal levels operated on, and duration of hospital stay most significantly associated with an increased risk of postoperative infection were age greater than 70 years (RR 5.954 [95% CI 1.622–10.141], p = 0.009), more than 2 previous spinal surgery levels (RR 9.0821 [95% CI 1.688–19.033], p = 0.007), and hospital stay greater than 7 days (RR 4.620 [95% CI 1.435–15.121], p = 0.01).
DiscussionIn this study of 817 consecutive patients who under-
went posterior lumbar instrumented fusion for degenera-tive spine disease, postoperative spine infection developed in 37 patients (4.5%), of whom 18 (49%) had a suprafascial infection and 19 (51%) had an infection below the fascia. The factors independently associated with an increased risk of infection in this patient population were age greater than 70 years, diabetes, obesity, previous spinal surgery, and staying more than 7 days in the hospital. Ninety-two percent of the patients were treated without hardware re-moval.
Previous Postoperative Spinal Infection StudiesThe overwhelming majority of previous studies on
postoperative spinal infections have included disparate patient populations (Table 1). Several of these studies include patients who did not undergo instrumented fu-sion.1,6,11,12,22,29–31,34,45,46 Pull ter Gunne et al. evaluated 3174 patients who underwent various types of spine surgery and found that 132 patients developed postoperative spine infection.34 The number of total patients who underwent fusion without instrumentation was not reported, but 27 (20%) of the 132 patients with infection did not have in-strumentation.34 Among this disparate group of patients, they found that deep infections could typically be treated with debridement, while superficial infections could be treated medically.34 Olsen and colleagues studied 2316 pa-tients who underwent orthopedic spine surgery, and 635 of these patients did not undergo instrumented fusion.30 The factors associated with an increased risk of infection included diabetes, serum glucose levels, obesity, number of residents involved in the surgery, and noncervical spine cases.30 More recently, Kurtz et al. evaluated, in the Medi-care population database, the incidence of infection in pa-tients older than 65 years.18 They found that the incidence of infection in this older population was 8.5% for primary surgeries, and the risk of infection was most influenced by increased Charlson comorbidity index, greater than or equal to 9 levels of surgery, and revision surgery, as well as obesity, surgical approach, and year of index procedure.18
TABLE 2: Summary of pre-, peri-, and postoperative characteristics in 817 consecutive patients who underwent lumbar fusion for degenerative spine disease at a single institution between 1993 and 2010*
* Values are presented as the number (%) of patients unless otherwise specified.† Values are presented as the mean ± SD. ‡ Values are presented as the median (IQR).
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In addition to studies including patients who did not undergo instrumented fusion, several studies have in-cluded a significant number of patients with different pa-thologies1–3,11,12,14,16,20,22,25,29,30,34,38,39,41,42,45,46 and spinal lev-els.1,6,11,12,22,29,30,34,37,45,46 Patients with different pathologies are known to have different risks of infections. Weinstein et al. reviewed 2391 consecutive patients who underwent spine surgery and found 46 patients who developed post-operative infection.45 They reported that infection was highest in patients with metastatic spine disease.45 Olsen and colleagues compared 41 patients who developed in-fections following spine surgery over a 4-year period with 178 randomly selected controls.29 They found that procedures for tumor resection were associated with an increased risk of infection.29 Blam et al. evaluated only trauma patients, of whom 57% had cervical spine inju-ries.6 They found that 24 of 256 trauma patients developed infections. Similarly, Sponseller and colleagues found that 25 of 210 patients who underwent neuromuscular scoliosis surgery developed infections.42 Of these 25 patients with postoperative spine infections, 16 had myelomeningoceles and 9 had cerebral palsy.42 The degree of cognitive im-pairment and use of allograft were associated with an in-creased risk of infection.42
Previous studies have also used case-control analy-ses rather than multivariate analyses to identify factors associated with postoperative spinal infection.11,12,22,29,32,39 This does not control for interrelated factors. Maragakis and colleagues compared 104 patients who developed spinal infections to 104 patients randomly selected who underwent any type of spine surgery.22 They found that prolonged a duration of surgery greater than the 75th per-centile, lumbosacral operative level, posterior approach, obesity, instrumentation, use of a razor for shaving pre-
operatively, and intraoperative administration of less than 50% oxygen were all independent risk factors for surgical-site infection after spinal surgery.22 Similarly, Fang and colleagues studied 1095 patients who under-went any type of spine surgery11 and reported found that infection occurred in 48 patients. They compared these 48 patients to 95 randomly selected patients and found that older age, positive smoking status, diabetes, previous infection, increased body mass index, and alcohol abuse were all higher in the group that developed.11 In addition to case-control studies, several studies have attempted to identify risk factors for infections by using administrative databases.1,18,25,41 While these databases are larger, they are prone to errors in coding, capturing all cases, and er-rors in diagnosis, among others.47
Factors Associated With Postoperative Spinal InfectionPatients with an increased age in this study had an in-
creased risk of postoperative spinal infection, and patients greater than 70 years of age had the highest risk. This find-ing has been seen in previous studies of patients undergo-ing any type of spine surgery.11,24 Older patients not only have less robust immune systems but are generally less able to tolerate long operative times, have poorer physi-ological reserves, and have an increased risk of complica-tions than younger patients.19,23 Further compounding this issue is that degenerative spine disease is more common in older patients.9,35 More meticulous sterile techniques and infection prevention should therefore be pursued in older patients undergoing spinal fusion for degenerative spine disease.
Patients who were obese or had diabetes had a more than 6- and 5-fold increased risk of infection in this study, respectively. Patients were defined as obese if there body
TABLE 3: Multivariate associations of pre- and perioperative variables with wound infection in 817 consecutive patients who underwent lumbar fusion for degenerative spine disease at a single institution between 1993 and 2010*
Variable Relative Risk (95% CI) p Value
factors positively associated w/ infection age 1.004 (1.001–1.009) 0.049 age >70 yrs 5.954 (1.622–10.141) 0.009 diabetes 5.583 (1.322–19.737) 0.02 obesity 6.216 (1.832–9.338) 0.005 previous spine surgery 2.994 (1.263–9.346) 0.009 >2 previous spinal surgery levels 9.082 (1.688–19.033) 0.007 days of hospital stay 1.155 (1.076–1.230) 0.0003 hospital stay >7 days 4.620 (1.435–15.121) 0.01factors notably not associated w/ infection smoker 1.094 (0.465–2.290) 0.82 no. of surgical levels 1.296 (0.705–2.269) 0.39 no. of fused levels 1.270 (0.688–2.71) 0.24 no. of decompressed levels 0.978 (0.736–1.293) 0.87 CSF leak 1.444 (0.061–3.907) 0.78 periop DVT/PE 3.238 (0.182–14.997) 0.33
* In a separate multivariate model, age and hospital stay were dichotomized into the multivariate analysis to find the greatest statistical association with wound infection. DVT = deep vein thrombosis; PE = pulmonary embolism.
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mass index was greater than 35. Longer operative times and more wound healing issues are typically present pa-tients who are obese, and these factors have been docu-mented in studies not limited to patients with posterior lumbar fusion.12,24,27 Diabetic patients, on the other hand, not only have an increased propensity for infections, but several clinical studies have shown that hyperglycemia increases morbidity and mortality rates, length of hospi-tal stay, and long-term functional deficits in critically ill patients.8,17,33,43,48 Hyperglycemia is also associated with perioperative morbidity and mortality in terms of several processes involving the CNS, including aneurysms26 and brain tumors.7 Thus, potential preoperative weight loss, strict glucose control, maintenance of sterile techniques, and use of infection control measures are especially criti-cal in obese and/or diabetic patients.
Patients with a history of lumbar spinal surgery and/or with a longer duration of hospitalization were also at an increased risk of infection. As with obesity, patients who have previously undergone lumbar surgery typically have longer surgery times, increased procedural complexity, and propensity for durotomies.46 The present study found that this was most significant for patients in whom 3 or more spinal levels were previously operated on. In addi-tion, patients with longer periods of hospitalization also had an increased risk of infection, and patients who stayed for greater than 7 days had the greatest risk. It has been shown in the literature that increased hospital stay is as-sociated with an increased risk of nosocomial infections, including urinary tract infections, pneumonia, and blood-stream infections.44 Moreover, these infections occur with more virulent and antibiotic-resistant organisms.44 Every attempt therefore should be made to discharge patients from the hospital as soon as possible to minimize nosoco-mial infections including wound-site infections.
Treatment of Postoperative Spinal InfectionIt is well known that the use of instrumentation is as-
sociated with an increased risk of infection.22,24,45 There is a concern that the only way to eradicate infections in these cases is to remove the previously implanted hard-ware.4,15,40 In present series, only 3 patients (8%) had their hardware removed as part of the infection workup. The overwhelming majority of patients were treated with some combination of incision and drainage and/or antibiotics. None of the patients had signs of recurrent infection at last follow-up. This is similar to the findings of Falavigna et al., who treated 13 patients with deep wound infections that did not involve hardware removal.10 Therefore, this study shows that infections may be eradicated without hardware removal in the majority of cases. This study also supports the notion of attempting less aggressive means of eradicating infection before considering hardware remov-al, as explantation in many cases will not required this to control infection.
Strength and LimitationsWe believe this study provides several useful insights.
First, the risk of infection is unclear for patients who are undergoing instrumented posterior lumbar fusion to treat degenerative spine disease. Because previous studies have
included disparate patient populations, the findings are not necessarily applicable to patients undergoing instrument-ed fusion for lumbar degenerative spine disease.11,29,30,45,46 Second, our study identifies factors independently associ-ated with infection for this patient population. Older age, diabetes, obesity, previous lumbar surgery, and longer hospital stay were all independently associated with infec-tion. Patients in whom these factors are present should be considered for stricter implementation of infection control measures including sterile technique, longer duration of perioperative antibiotics, and potentially closer surveil-lance. Third, we found that hardware removal is typically not necessary for infection control. Surgical debridement and/or antibiotic administration are usually sufficient at eradicating infections. This study may therefore provide useful information for helping to minimize infection in patients undergoing lumbar fusion for degenerative spine disease.
This study, however, has some limitations. One is that it was not designed to evaluate the efficacy of sterilization techniques or peri- and postoperative antibiotic regimens. The sterilization techniques and perioperative antibiotic regimen and duration were not consistently recorded, and therefore, their effect on outcome could not be assessed. Additionally, a small minority of patients was lost to fol-low-up. As a result, some patients who developed late in-fections that were treated elsewhere may have been missed in our study. Moreover, the type of hardware was not rou-tinely recorded. Therefore, associations between hardware type and the development of postoperative infections were not analyzed. Additionally, this study was underpowered to evaluate if hardware removal was necessary for infec-tion treatment. Of the 37 patients in whom postoperative wound infection developed, only 3 (8%) required hard-ware removal. Larger studies with longer follow-up times are needed. Finally, this study is inherently limited by its retrospective design. As a result, there may be an inher-ent bias associated with patient selection and treatment, as well as missing patient information. However, we tried to create a uniform patient population by utilizing strict inclusion criteria, thus providing more relevant informa-tion for patients undergoing posterior lumbar fusion for degenerative spine disease. Given these criteria and rela-tively precise outcome measures, we believe our findings are useful for the care of patients with degenerative spine disease. However, prospective studies are needed to pro-vide better data to guide clinical decision making.
ConclusionsPosterior lumbar fusion for degenerative spine dis-
ease is a relatively common procedure, with an increas-ing number of procedures performed each year. A feared complication of these procedures is postoperative spinal infection. This study found that approximately 4% of pa-tients developed an infection. The factors independently associated with an increased risk of infection were older age, diabetes, obesity, prior surgery, and prolonged hospi-tal stay. Ninety-two percent of the patients who developed a postoperative infection were treated successfully with surgery and/or antibiotics, without necessity for hardware removal.
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Disclosure
Dr. Sciubba is a consultant for DePuy, Medtronic, NuVasive, and Globus. Dr. A. Bydon has received non–study related support from DePuy Spine. Dr. Gokaslan is a stockholder in US Spine and Spinal Kinetics; he received research support for the current study from AOSpine, NREF, and DePuy; and he is on the editorial boards of the following: Journal of Neurosurgery: Spine, Journal of Spinal Disorders, European Spine Journal, Nature Review, World Neuro-surgery, and Journal of Surgical Oncology. Dr. Witham has received non–study related support from Eli Lilly.
Author contributions to the study and manuscript prepara-tion include the following. Conception and design: Chaichana, Mc Loughlin, Sciubba, Gokaslan, Witham. Acquisition of data: M By don, Santiago-Dieppa, Hwang, McLoughlin. Analysis and inter-pretation of data: Chaichana, M Bydon, McLoughlin, Wolinsky, A Bydon, Gokaslan, Witham. Drafting the article: Chaichana, M By don, Gokaslan, Witham. Critically revising the article: all authors. Re viewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Chai-chana. Statistical analysis: Chaichana, M Bydon. Administrative/tech nical/material support: Witham. Study supervision: Gokaslan.
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Manuscript submitted January 18, 2013.Accepted October 3, 2013.Please include this information when citing this paper: published
online November 8, 2013; DOI: 10.3171/2013.10.SPINE1364.Address correspondence to: Kaisorn L. Chaichana, M.D., Depart-
ment of Neurosurgery, The Johns Hopkins Hospital, Johns Hopkins University, 600 N. Wolfe St., Meyer 8-184, Baltimore, MD 21202. email: [email protected].
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