Peter L. Zhou

Does Preadmission Cutaneous Chlorhexidine Preparation Reduce Surgical Site Infections After Total Knee Arthroplasty

BackgroundMany preventive methodologies seek to reduce the risk of surgical site infections after total knee arthroplasty (TKA), including the use of preoperative chlorhexidine baths and cloths. Although we have demonstrated in previous studies that this may be an efficacious method for infection prevention, our study was underpowered and we therefore set out to evaluate this with a larger sample size.Questions/purposes(1) Does a preadmission chlorhexidine cloth skin preparation protocol decrease the risk of surgical site infection in patients undergoing TKA? (2) When stratified using the National Healthcare Safety Network (NHSN) risk categories, which categories are associated with risk reduction from the preadmission chlorhexidine preparation protocol?MethodsIn our study, all patients (3717 total) who had undergone primary or revision TKA at a single institution between January 1, 2007, and December 31, 2013, were identified, of whom 991 patients used the chlorhexidine cloths before surgery and 2726 patients did not. All patients were provided cloths with instructions before surgery; however, as a result of a lack of compliance, we were able to substratify patients into treatment and control cohorts. Additionally, we substratified patients by NHSN risk category to determine differences in infection between the two cohorts (cloth versus no cloth). Patient medical records and an infection-tracking database were reviewed to determine the development of periprosthetic infection (patients who had superficial infections were excluded from our study) in both groups after 1 year surveillance. We then calculated relative risk reductions with use of chlorhexidine gluconate and stratified results based on NHSN risk category.ResultsUse of a preoperative chlorhexidine cloth skin preparation protocol is associated with reduced relative risk of periprosthetic infection after TKA (infections with protocol: three of 991 [0.3%]; infections in control: 52 of 2726 [1.9%]; relative risk [RR]: 6.3 [95% confidence interval [CI], 1.9–20.1]; p = 0.002). When stratified by NHSN risk category, periprosthetic infection risk reduction was seen in the medium-risk category (protocol: one of 402 [0.3%]; control: 25 of 1218 [2.0%]; RR, 8.3 [CI, 1.1–60.7]; p = 0.038), but no significant difference was detected in the low- and medium-risk groups (RR, 2.1 [CI, 0.5–9.6; p = 0.33] and RR, 11.3 [CI, 0.7–186.7; p = 0.09]).ConclusionsA prehospital chlorhexidine gluconate wipe protocol appears to reduce the risk of periprosthetic infections after TKA, primarily in those patients with medium and high risk. Although future multicenter randomized trials will need to confirm these preliminary findings, the intervention is inexpensive and is unlikely to be risky and therefore might be considered on the basis of this retrospective, comparative study.Level of EvidenceLevel III, therapeutic study.

Traumatic Fractures of the Cervical Spine: Analysis of Changes in Incidence, Etiology, Concurrent Injuries and Complications Among 488,262 Patients from 2005-2013

OBJECTIVEnThe causes and epidemiology of traumatic cervical spine fracture have not been described with sufficient power or recency. Our goal is to describe demographics, incidence, cause, spinal cord injuries (SCIs), concurrent injuries, treatments, and complications of traumatic cervical spine fractures.nnnMETHODSnA retrospective review was carried out of the Nationwide Inpatient Sample. International Classification of Disease, Ninth Revision E-codes identified trauma cases from 2005 to 2013. Patients with cervical fracture were isolated. Demographics, incidence, cause, fracture levels, concurrent injuries, surgical procedures, and complications were analyzed. t tests elucidated significance for continuous variables and χ2 for categorical variables. Level of significance was P < 0.05.nnnRESULTSnA total of 488,262 patients were isolated (age, 55.96 years; male, 60.0%; white, 77.5%). Incidence (2005, 4.1% vs. 2013, 5.4%), Charlson Comorbidity Index (2005, 0.6150 vs. 2013, 1.1178), and total charges (2005,

A novel index for quantifying the risk of early complications for patients undergoing cervical spine surgeries

71,228.60 vs. 2013,

The Influence of Body Mass Index on Achieving Age-Adjusted Alignment Goals in Adult Spinal Deformity Corrective Surgery with Full-Body Analysis at 1 Year

108,119.29) have increased since 2005, whereas length of stay decreased (2005, 9.22 vs. 2013, 7.86) (all Pxa0<xa00.05). The most common causes were motor vehicle accident (29.3%), falls (23.7%), and pedestrian accidents (15.7%). The most frequent fracture types were closed at C2 (32.0%) and C7 (20.9%). Concurrent injury rates have significantly increased since 2005 (2005, 62.3% vs. 2013, 67.6%). Common concurrent injuries included fractures to the rib/sternum/larynx/trachea (19.6%). Overall fusion rates have increased since 2005 (2005, 15.7% vs. 2013, 18.0%), whereas decompressions and halo insertion rates have decreased (all P < 0.05). SCIs have significantly decreased since 2005, except for upper cervical central cord syndrome. Complication rates have significantly increased since 2005 (2005, 31.6% vs. 2013, 36.2%). Common complications included anemia (7.7%), mortality (6.6%), and acute respiratory distress syndrome (6.6%).nnnCONCLUSIONSnIncidence, complications, concurrent injuries, and fusions have increased since 2005. Length of stay, SCIs, decompressions, and halo insertions have decreased. Indicated trends should guide future research in management guidelines.

Full-Body Analysis of Adult Spinal Deformity Patients' Age-Adjusted Alignment at 1 Year

OBJECTIVE It is becoming increasingly necessary for surgeons to provide evidence supporting cost-effectiveness of surgical treatment for cervical spine pathology. Anticipating surgical risk is critical in accurately evaluating the risk/benefit balance of such treatment. Determining the risk and cost-effectiveness of surgery, complications, revision procedures, and mortality rates are the most significant limitations. The purpose of this study was to determine independent risk factors for medical complications (MCs), surgical complications (SCs), revisions, and mortality rates following surgery for patients with cervical spine pathology. The most relevant risk factors were used to structure an index that will help quantify risk and anticipate failure for such procedures. METHODS The authors of this study performed a retrospective review of the National Inpatient Sample (NIS) database for patients treated surgically for cervical spine pathology between 2001 and 2010. Multivariate models were performed to calculate the odds ratio (OR) of the independent risk factors that led to MCs and repeated for SCs, revisions, and mortality. The models controlled for age (< and > 65 years old), sex, race, revision status (except for revision analysis), surgical approach, number of levels fused/re-fused (2-3, 4-8, ≥ 9), and osteotomy utilization. ORs were weighted based on their predictive category: 2 times for revision surgery predictors and 4 times for mortality predictors. Fifty points were distributed among the predictors based on their cumulative OR to establish a risk index. RESULTS Discharges for 362,989 patients with cervical spine pathology were identified. The mean age was 52.65 years, and 49.47% of patients were women. Independent risk factors included medical comorbidities, surgical parameters, and demographic factors. Medical comorbidities included the following: pulmonary circulation disorder, coagulopathy, metastatic cancer, renal failure, congestive heart failure, alcohol abuse, neurological disorder, nonmetastatic cancer, liver disease, rheumatoid arthritis/collagen vascular diseases, and chronic blood loss/anemia. Surgical parameters included posterior approach to fusion/re-fusion, ≥ 9 levels fused/re-fused, corpectomy, 4-8 levels fused/re-fused, and osteotomy; demographic variables included age ≥ 65 years. These factors increased the risk of at least 1 of MC, SC, revision, or mortality (risk of death). A total of 50 points were distributed among the factors based on the cumulative risk ratio of every factor in proportion to the total risk ratios. CONCLUSIONS This study proposed an index to quantify the potential risk of morbidity and mortality prior to surgical intervention for patients with cervical spine pathology. This index may be useful for surgeons in patient counseling efforts as well as for health insurance companies and future socioeconomics studies in assessing surgical risks and benefits for patients undergoing surgical treatment of the cervical spine.

Differences in primary and revision deformity surgeries: following 1,063 primary thoracolumbar adult spinal deformity fusions over time

BACKGROUNDnThe impact of obesity on global spinopelvic alignment is poorly understood. This study investigated the effect of body mass index on achieving alignment targets and compensation mechanisms after corrective surgery for adult spinal deformity (ASD).nnnMETHODSnRetrospective review of a single-center database. Inclusion: patients ≥18 years with full-body stereographic images (baseline and 1 year) and who met ASD criteria (sagittal vertical axis [SVA] >5 cm, pelvic incidence minus lumbar lordosis [PI-LL] >10°, coronal curvature >20° or pelvic tilt >20°). Patients were stratified by age (<40, 40-65, and ≥65 years) and body mass index (<25, 25-30, and >30). Postoperative alignment was compared with age-adjusted ideal values. Prevalence of patients who matched ideals and unmatched (undercorrected/overcorrected) was assessed. Health-related quality of life (HRQL) scores, alignment, and compensatory mechanisms were compared across cohorts using analysis of variance and temporally with paired t tests.nnnRESULTSnA total of 116 patients were included (average age, 62 years; 66% female). After corrective surgery, obese and overweight patients had more residual malalignment (worse PI-LL, T1 pelvic angle, pelvic tilt, and SVA) compared with normal patients (P < 0.05). In addition, obese and overweight patients recruited more pelvic shift (obese, 62.36; overweight, 49.80; normal, 31.50) and had a higher global sagittal angle (obese, 6.51; overweight, 6.35; normal, 3.40) (P < 0.05). Obese and overweight patients showed lower overcorrection rates and higher undercorrection rates (P < 0.05). Obese patients showed worse postoperative HRQL scores (Scoliosis Research Society 22 Questionnaire, Oswestry Disability Index, visual analog scale-leg) than did overweight and normal patients (P < 0.05). Obese and overweight patients who matched age-adjusted alignment targets for SVA or PI-LL showed no HRQL improvements (P > 0.05).nnnCONCLUSIONSnAfter surgery, obese patients were undercorrected, showed more residual malalignment, recruited more pelvic shift, and had a greater global sagittal angle and worse HRQL scores. The benefits from age-adjusted alignment targets seem to be less substantial for obese and overweight patients.

Developments in the treatment of Chiari type 1 malformations over the past decade

BACKGROUNDnPrevious studies have built a foundation for understanding compensation in patients with adult spinal deformity (ASD) by using full-body stereographic assessments. These mechanisms, in relation to age-adjusted alignment targets, have yet to be studied fully. The aim of this study was to assess lower-limb compensatory mechanisms of patients failing to meet age-adjusted alignment goals.nnnMETHODSnPatients with ASD ≥40 years with full body baseline and follow-up radiographs were included. Patients were stratified by age (40-65 years, >65 years) and spinopelvic correction. Lower-limb compensation parameters (pelvic shift, hip extension, knee flexion [KA], ankle flexion [AA], and global sagittal angle [GSA]) for patients who matched and failed to match age-adjusted alignment targets were compared with analysis of variance and t-test analysis.nnnRESULTSnIn total, 108 patients were included. At 1 year, AA increased with age in the match pelvic tilt (PT) andxa0spinopelvic mismatch (PI-LL) cohorts (PT: AA, 5.6-7.8, Pxa0= 0.041; PI-LL: 4.9-8.8, Pxa0= 0.026). KA, AA, and GSA increased with age in the match sagittal vertical axis (SVA) cohort (KA: 3.8-13.1, Pxa0= 0.002; AA: 5.8-10.2, Pxa0=xa00.008; GSA: 3.9-7.8, P < 0.001), as did KA and GSA in the match T1 pelvic angle group (KA: 1.8-8.7, Pxa0= 0.020; GSA: 2.6-5.7, Pxa0= 0.004).nnnCONCLUSIONSnGreater compensation captured by KA and GSA was associated with age progression in the match SVA and T1 pelvic angle cohorts. In addition, older SVA, PT, and PI-LL match cohorts used increased AA, suggesting that ideal postoperative alignment of aged individuals with ASD involves increased compensation.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P127. Redefining the cervical disability threshold of T1 slope minus cervical lordosis

BackgroundnThis study aims to describe properties of adult spinal deformity (ASD) revisions relative to primary surgeries and determine clinical variables that can predict revision. ASD is a common pathology that can lead to decreased quality of life, pain, physical limitations, and dissatisfaction with self-image. Durability of interventions for deformity treatment is of paramount concern to surgeons, as revision rates remain high.nnnMethodsnPatients undergoing thoracolumbar fusion, five or more levels, for scoliosis (primary diagnosis ICD-9 737.x) were identified on a state-wide database. Primary and revision (returning for re-fusion procedure) surgeries were compared based on demographic, hospital stay, and clinical characteristics. Differences between primary and revision surgeries, and predictors of primary surgeries requiring revision, utilized binary logistic regression controlling for age, comorbidity burden, and levels fused.nnnResultsnA total of 1,063 patients (average 7.4 levels fused, mean age: 47.6 years, 69.0% female) undergoing operative treatment for ASD were identified, of which 123 (average 7.1 levels fused, 11.6%, mean age 61.43, 80.5% female) had surgical revision. Primary surgeries were ~0.3 levels longer (P=0.013), used interbody ~11% more frequently (P=0.020), and used BMP ~12% less frequently (P=0.008). Revisions occurred 176.4 days after the primary on average. The most frequent causes of revisions were: 43.09% implant failure, 24.39% acquired kyphosis, and 14.63% enduring scoliosis. After controlling for age, comorbidities, and levels fused older, more comorbid, female, and white-race patients were more likely to be revised. Upon multivariate regression, after controlling for age and levels fused, overall complications remained non-different (OR: 0.8, 95% CI: 0.6-1.2). However, revision remained an independent predictor for infection (OR: 5.5, 95% CI: 2.8-10.5).nnnConclusionsnIn a statewide database with individual patient follow up of up to 4 years 10% of ASD patients undergoing scoliosis correction required revision. Revision surgeries had higher infection incidence.

Thursday, September 27, 2018 8:30 AM–9:30 AM Best Papers

BackgroundnChiari malformations type 1 (CM-1), a developmental anomaly of the posterior fossa, usually presents in adolescence or early adulthood. There are few studies on the national incidence of CM-1, taking into account outcomes based on concurrent diagnoses. To quantify trends in treatment and associated diagnoses, as retrospective review of the Kids Inpatient Database (KID) from 2003-2012 was conducted.nnnMethodsnPatients aged 0-20 with primary diagnosis of CM-1 in the KID database were identified. Demographics and concurrent diagnoses were analyzed using chi-squared and t-tests for categorical and numerical variables, respectively. Trends in diagnosis, treatments, and outcomes were analyzed using analysis of variance (ANOVA).nnnResultsnFive thousand four hundred and thirty-eight patients were identified in the KID database with a primary diagnosis of CM-1 (10.5 years, 55% female). CM-1 primary diagnoses have increased over time (45 to 96 per 100,000). CM-1 patients had the following concurrent diagnoses: 23.8% syringomyelia/syringobulbia, 11.5% scoliosis, 5.9% hydrocephalus, 2.2% tethered cord syndrome. Eighty-three point four percent of CM-1 patients underwent surgical treatment, and rate of surgical treatment for CM-1 increased from 2003-2012 (66% to 72%, P<0.001) though complication rate decreased (7% to 3%, P<0.001) and mortality rates remained constant. Seventy percent of surgeries involved decompression-only, which increased neurologic complications compared to fusions (P=0.039). Cranial decompressions decreased from 2003-2012 (42.2-30.5%) while spinal decompressions increased (73.1-77.4%). Fusion rates have increased over time (0.45% to 1.8%) and are associated with higher complications than decompression-only (11.9% vs. 4.7%). Seven point four percent of patients experienced at least one peri-operative complication (nervous system, dysphagia, respiratory most common). Patients with concurrent hydrocephalus had increased; nervous system, respiratory and urinary complications (P<0.006) and syringomyelia increased the rate of respiratory complications (P=0.037).nnnConclusionsnCM-1 diagnoses have increased in the last decade. Despite the decrease in overall complication rates, fusions are becoming more common and are associated with higher peri-operative complication rates. Commonly associated diagnoses including syringomyelia and hydrocephalus, can dramatically increase complication rates.