Christopher Wang

Prevalence and motion characteristics of degenerative cervical spondylolisthesis in the symptomatic adult.

Study Design. Retrospective analysis of kinetic magnetic resonance images. Objective. To define the prevalence of degenerative cervical spondylolisthesis in symptomatic patients and to analyze the motion characteristics and influence on the spinal canal at the affected level. Summary of Background Data. When compared with lumbar spondylolisthesis, there are few studies evaluating cervical spondylolisthesis, and the prevalence and motion characteristics of cervical spondylolisthesis are not well defined. Methods. Four hundred sixty-eight symptomatic patients underwent upright cervical kinetic magnetic resonance images in neutral, flexion, and extension positions. Segmental displacement and intervertebral angles were measured in 3 positions using computer analysis software. Spondylolisthesis was defined as the vertebral displacement more than 2 mm, and graded based on the magnitude into 2 groups at each level: grade 1 (2–3 mm), grade 2 (>3 mm). Instability was defined as segmental translational motion exceeding 3 mm. Results. Grade 1 and 2 spondylolisthesis at a minimum of 1 level were observed with a prevalence of 16.4% and 3.4% of all patients, respectively. The most affected levels were C4–C5 (6.2%) and C5–C6 (6.0%) followed by C3–C4 (3.6%) and C6–C7 (3.0%). Translational motion was greater in levels with grade 1 as compared with segments without spondylolisthesis, but there was no difference in angular motion between the 3 groups. Translational instability was observed with a prevalence of 16.7% in grade 2, 4.3% in grade 1, and 3.4% in segments without spondylolisthesis. Space available for the cord at the affected level was decreased and spinal cord compression grade was higher in grade 1 and grade 2 as compared with levels without spondylolisthesis. Conclusion. Cervical spondylolisthesis of at least 2 mm was observed in 20% of patients and was most common at C4–C5 and C5–C6. The presence of spondylolisthesis was associated with increased translational motion and decreased segmental spinal canal diameter. Level of Evidence: N/A

Kinetic Magnetic Resonance Imaging of the Cervical Spine: A Review of the Literature

Study Design Literature review. Objective The purpose of this study is to compile and review the body of literature related to kinetic magnetic resonance imaging (kMRI) of the cervical spine. Methods A review of literature related to kMRI was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Results We included 16 prospective and retrospective studies of symptomatic and asymptomatic patients who underwent kMRI of the cervical spine. Conclusions Data suggest that kMRI is able to provide meaningful information regarding changes in the cervical spine in both normal and pathologic segments. A prospective study comparing magnetic resonance imaging and kMRI is needed to confirm clinically utility of this technology.

Outpatient Total Knee Arthroplasty Is Associated with Higher Risk of Perioperative Complications

Background: As concerns regarding health-care expenditure in the U.S. remain at the national forefront, outpatient arthroplasty is an appealing option for carefully selected patient populations. The purpose of this study was to determine the nationwide trends and complication rates associated with outpatient total knee arthroplasty (TKA) in comparison with standard inpatient TKA. Methods: We performed a retrospective review of the Humana subset of the PearlDiver Patient Record Database to identify patients who had undergone TKA (Current Procedural Terminology [CPT] code 27447) as either outpatients or inpatients from 2007 to 2015. The incidence of perioperative medical and surgical complications was determined by querying for relevant International Classification of Diseases, Ninth Revision (ICD-9) and CPT codes. Multivariate logistic regression analysis adjusted for age, sex, and Charlson Comorbidity Index (CCI) was used to calculate odds ratios (ORs) of complications among outpatients relative to inpatients treated with TKA. Results: Cohorts of 4,391 patients who underwent outpatient TKA and 128,951 patients who underwent inpatient TKA were identified. The median age was in the 70 to 74-year age group in both cohorts. The incidence of outpatient TKA increased across the study period (R2 = 0.60, p = 0.015). After adjustment for age, sex, and CCI, outpatient TKAs were found to more likely be followed by tibial and/or femoral component revision due to a noninfectious cause (OR = 1.22, 95% confidence interval [CI] = 1.01 to 1.47; p = 0.039), explantation of the prosthesis (OR = 1.35, CI = 1.07 to 1.72; p = 0.013), irrigation and debridement (OR = 1.50, CI = 1.28 to 1.77; p < 0.001), and stiffness requiring manipulation under anesthesia (OR = 1.28, CI = 1.17 to 1.40; p < 0.001) within 1 year. Outpatient TKA was also more frequently associated with postoperative deep vein thrombosis (OR = 1.42, CI = 1.25 to 1.63; p < 0.001) and acute renal failure (OR = 1.13, CI = 1.01 to 1.25; p = 0.026). Conclusions: With the potential to minimize arthroplasty costs among healthy patients, outpatient TKA is an increasingly popular option. Nationwide data from a private insurance database demonstrated a higher risk of perioperative surgical and medical complications including component failure, surgical site infection, knee stiffness, and deep vein thrombosis. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Ambulatory anterior cervical discectomy and fusion is associated with a higher risk of revision surgery and perioperative complications: an analysis of a large nationwide database

BACKGROUND CONTEXT With the changing landscape of health care, outpatient spine surgery is being more commonly performed to reduce cost and to improve efficiency. Anterior cervical discectomy and fusion (ACDF) is one of the most common spine surgeries performed and demand is expected to increase with an aging population. PURPOSE The objective of this study was to determine the nationwide trends and relative complication rates associated with outpatient ACDF. STUDY DESIGN/SETTING This is a large-scale retrospective case control study. PATIENT SAMPLE The patient sample included Humana-insured patients who underwent one- to two-level ACDF as either outpatients or inpatients from 2011 to 2016 OUTCOME MEASURES: The outcome measures included incidence and the adjusted odds ratio (OR) of postoperative medical and surgical complications within 1 year of the index surgery. MATERIALS AND METHODS A retrospective review was performed of the PearlDiver Humana insurance records database to identify patients undergoing one- to two-level ACDF (Current Procedural Terminology [CPT]-22551 and International Classification of Diseases [ICD]-9-816.2) as either outpatients or inpatients from 2011 to 2016. The incidence of perioperative medical and surgical complications was determined by querying for relevant ICD and CPT codes. Multivariate logistic regression adjusting for age, gender, and Charlson Comorbidity Index was used to calculate ORs of complications among outpatients relative to inpatients undergoing ACDF. RESULTS Cohorts of 1,215 patients who underwent outpatient ACDF and 10,964 patients who underwent inpatient ACDF were identified. The median age was in the 65-69 age group for both cohorts. The annual relative incidence of outpatient ACDF increased from 0.11 in 2011 to 0.22 in 2016 (R2=0.82, p=.04). Adjusting for age, gender, and comorbidities, patients undergoing outpatient ACDF were more likely to undergo revision surgery for posterior fusion at both 6 months (OR 1.58, confidence interval [CI] 1.27-1.96, p<.001) and 1 year (OR 1.79, CI 1.51-2.13, p<.001) postoperatively. Outpatient ACDF was also associated with a higher likelihood of revision anterior fusion at 1 year postoperatively (OR 1.46, CI 1.26-1.70, p<.001). Among medical complications, postoperative acute renal failure was more frequently associated with outpatient ACDF than inpatient ACDF (OR 1.25, CI 1.06-1.49, p=.010). Adjusted rates of all other queried surgical and medical complications were comparable. CONCLUSIONS Outpatient ACDF is increasing in frequency nationwide over the past several years. Nationwide data demonstrate a greater risk of perioperative surgical complications, including revision anterior and posterior fusion, as well as a higher risk of postoperative acute renal failure. Candidates for outpatient ACDF should be counseled and carefully selected to reduce these risks.

Postoperative complications in adult spinal deformity patients with a mental illness undergoing reconstructive thoracic or thoracolumbar spine surgery

BACKGROUND CONTEXT Previous studies have found an association between mental illness and poor outcomes in spine surgery, but little is known about the effects of depression and/or anxiety on the adult spinal deformity population. In addition, most relevant studies exclusively focused on the lumbar spine and had relatively small patient sizes. PURPOSE The aim of this study was to investigate whether adult spinal deformity patients with depression and/or anxiety have an increased risk of postoperative complications and reoperation following posterior thoracolumbar spinal surgery. STUDY DESIGN/SETTING Retrospective database study. METHODS Adult patients (over 18 years of age) with a diagnosis of spinal deformity undergoing any reconstructive thoracic or thoracolumbar spinal procedure with a posterior approach between 2007 and 2015 Q2 were identified using Current Procedural Terminology codes to query the Pearl Diver patient record database (Pearl Diver Technologies, West Conshohocken, PA, USA). The database includes records of approximately 18 million patients across the United States having Humana insurance. Further selection of patients with depression and/or anxiety and their associated postoperative complications were identified using ICD-9 and ICD-10 diagnosis codes (International Classification of Diseases 9th-10th edition). The mental illness cohort was matched to a control group according to age, sex, and Charlson Comorbidity Index. Patient data was analyzed for reoperation rates and incidence of common postoperative complications. RESULTS Multilevel posterolateral fusion was the most common included posterior thoracic reconstructive surgery. The mental illness cohort (n = 327) had significantly increased rates of infection (odds ratio [OR] = 1.743, p = .022) and respiratory complications (OR = 1.492, p = .02) at the 90-day postoperative period. The rates of incision and drainage (OR = 1.379, p = .475) and pneumonia (OR = 1.22, p = .573) were increased in the mental illness cohort at the 90-day postoperative period, but not significantly. There were no significant differences in complication and reoperation rates at 1-year postoperatively. CONCLUSIONS Patients with spinal deformity and pre-existing depression and/or anxiety treated with a posterior thoracolumbar reconstructive spinal surgery had significantly elevated risk of postoperative infections and respiratory complications when compared with the control group.

Preoperative Vitamin D Deficiency Is Associated With Higher Postoperative Complication Rates in Total Knee Arthroplasty

The purpose of this study was to determine the relative incidence of postoperative complications in 25-hydroxyvitamin D (25D)-deficient and -sufficient patients undergoing total knee arthroplasty (TKA). Patients who were either serum 25D deficient (25D <20 ng/mL) or 25D sufficient (25D ≥20 ng/mL) 90 days prior to primary TKA from 2007 to 2016 were identified using the Humana administrative claims registry. The incidence of postoperative medical and surgical complications was determined by querying for relevant International Classification of Diseases, Ninth Revision and Current Procedural Terminology codes. Risk-adjusted odds ratios (ORs) were calculated using multivariate logistic regression with age, sex, and Charlson Comorbidity Index as covariates. In total, 868 of 6593 patients who underwent TKA from 2007 to 2016 were 25D deficient, corresponding to a 13.2% prevalence rate. On adjustment for age, sex, and Charlson Comorbidity Index, 25D-deficient patients had a higher incidence of postoperative stiffness requiring manipulation under anesthesia (OR, 1.69; 95% confidence interval [CI], 1.39-2.04; P<.001), surgical site infection requiring irrigation and debridement (OR, 1.76; 95% CI, 1.25-2.48; P=.001), and prosthesis explantation (OR, 2.97; 95% CI, 2.04-4.31; P<.001) at 1 year. Patients who were 25D deficient also had higher rates of postoperative deep venous thrombosis (OR, 1.80; 95% CI, 1.36-2.38; P<.001), myocardial infarction (OR, 2.11; 95% CI, 1.41-3.15; P<.001), and cerebrovascular accident (OR, 1.73; 95% CI, 1.17-2.57; P=.006). Thus, serum 25D levels below 20 ng/mL are associated with a higher incidence of postoperative complications and may be a perioperative modifiable risk factor in TKA. [Orthopedics. 2018; 41(4):e489-e495.].

Relative Complications and Trends of Outpatient Total Shoulder Arthroplasty

Outpatient arthroplasty is an appealing option among select patient populations as a mechanism for reducing health care expenditure. The purpose of this study was to determine the nationwide trends and complication profile of outpatient total shoulder arthroplasty (TSA). The authors reviewed a national administrative claims database to identify patients undergoing TSA as outpatients and inpatients from 2007 to 2016. The incidence of perioperative surgical and medical complications was determined by querying for relevant International Classification of Diseases, Ninth Revision, and Current Procedural Terminology codes. Multivariate logistic regression adjusted for age, sex, and Charlson Comorbidity Index was used to calculate odds ratios of complications among outpatients relative to inpatients undergoing TSA. The query identified 1555 patients who underwent outpatient TSA and 15,987 patients who underwent inpatient TSA. The median age was in the 70 to 74 years age group in both the outpatient and the inpatient cohorts, and the age distribution was comparable between the 2 cohorts (P=.287). The incidence of both outpatient (P<.001) and inpatient (P<.001) TSA increased during the study period. On adjustment for age, sex, and comorbidities, patients undergoing outpatient TSA had significantly lower rates of stiffness requiring manipulation under anesthesia (outpatient, 1.09%; inpatient, 2.35%; odds ratio, 0.52; 95% confidence interval, 0.38-0.71; P<.001) and higher rates of postoperative surgical site infections requiring reoperation (outpatient, 0.90%; inpatient, 0.65%; odds ratio, 1.65; 95% confidence interval, 1.15-2.35; P<.001) at 1 year. Rates of all other postoperative complications were comparable. Ambulatory TSA is increasing in incidence nationwide and is associated with an overall favorable postoperative complication profile. [Orthopedics. 2018; 41(3):e400-e409.].

The primary diagnosis and the coexisting anxiety disorders have no impact on the additional surgical procedure after spinal cord stimulators implantation: An analysis of 11,029 patients

Studies have demonstrated superior outcomes and cost effectiveness of the spinal cord stimulation (SCS) for the treatment of chronic pain syndromes such as failed back surgery syndrome (FBSS) or complex regional pain syndrome (CRPS). However, little is known about the impact of primary diagnosis or mental disorders on the revision rate. This is the Retrospective cohort study to analyze the reintervention rates based on the primary diagnosis or comorbid mental disorder. Data of the annual trends of SCS use, revision and removal rate of SCS and additional surgical rate after removal was collected and analyzed for patients undergoing SCS between 2007 and 2015, within a private insurance billing database. Trial cases were excluded from this study. The results showed 11,029 patients received SCS implantation with percutaneous electrodes (PE, n = 7418) or surgical electrode (SE, n = 3611). There was a trend of increasing use of SCS from 2007 to 2013, followed by a decrease in last two years. There was no significant difference in the neither removal nor revision rate regardless between the patients with FBSS or CRPS at each time point. Although the removal rates within 2 years were significantly higher in the patients with anxiety disorders compared to the patients without any mental disorders (PE: p < .001, SE: 0.003), the rate of additional surgery after the removal showed no significant difference (PE: p = .532, SE: p = .262). Therefore, we concluded that the primary diagnosis and the presence of anxiety disorders did not have an impact on the additional surgical rate following SCS implantation.

Complications and Risk Factors Using Structural Allograft Versus Synthetic Cage: Analysis 17 783 Anterior Cervical Discectomy and Fusions Using a National Registry

Study Design: Retrospective cohort study. Objective: To determine the rates of perioperative complications in patients undergoing anterior cervical discectomy and fusion (ACDF) with allograft versus synthetic cage. Methods: A large national administrative health care database was queried for ACDF procedures performed between 2007 and 2014 using ICD-9 (International Statistical Classification of Diseases, 9th revision) and CPT (Current Procedural Terminology) codes. Cases that utilized structural allograft and synthetic cages were identified via CPT codes. Gender, age, frequency of obesity, cigarette use, diabetes, and number of levels fused were compared between the 2 cohorts using χ2 test. Complications within 90 days were identified via ICD-9 codes and compared between the 2 cohorts. Revision rates within 2 years were noted. Results: A total of 10 648 ACDF cases using synthetic cages and 7135 ACDFs using structural allograft were identified. The demographics between the 2 cohorts were similar. Overall complication rate was 8.71% in the synthetic cage group compared with 7.76% in the structural allograft group (P < .01). Use of synthetic cage was associated with higher rate of respiratory complications, 0.57% compared with 0.31% in the structural allograft cohort (P = .03), while use of structural allograft was associated with a higher rate of dysphagia, 0.64% compared with 0.33% (P < .01). Revision rate at 2 years was 0.50% and 0.56% in the synthetic cage and allograft groups, respectively (P = .03). Conclusions: This data suggests that synthetic cages are associated with a marginally higher overall rate of complications with similar revision rates.

Utility of Intraoperative Neuromonitoring for Lumbar Pedicle Screw Placement Is Questionable: A Review of 9957 Cases

Study Design. A retrospective database study. Objective. The goal of this study was to (1) evaluate the trends in the use of electromyography (EMG) for instrumented posterolateral lumbar fusions (PLFs) in the United States and (2) assess the risk of neurological injury following PLFs with and without EMG. Summary of Background Data. Neurologic injuries from iatrogenic pedicle wall breaches during screw placement are known complications of PLFs. The routine use of intraoperative neuromonitoring (ION) such as EMG during PLF to improve the accuracy and safety of pedicle screw implantation remains controversial. Methods. A retrospective review was performed using the PearlDiver Database to identify patients who had PLF surgery with and without EMG for lumbar disorders from years 2007 to 2015. Patients undergoing concomitant interbody fusions or spinal deformity surgery were excluded. Demographic trends and risk of neurological injuries were assessed. Results. During the study period, 2007 to 2015, 9957 patients underwent PLFs. Overall, EMG was used in 2495 (25.1%) of these patients. There was a steady increase in the use of EMG from 14.9% in 2007 to 28.7% in 2009, followed by a steady decrease to 21.9% in 2015 (P < 0.0001). The risk of postoperative neurological injuries following PLFs was 1.35% (134/9957) with a risk of 1.36% (34/2495) with EMG and 1.34% (100/7462) without EMG (P = 0.932). EMG is used most commonly for PLFs in the Southern part of the United States. Conclusion. In this retrospective national database review, we found that there was a steady increase in the routine use of EMG for PLFs followed by a steady decline. Regional differences were observed in the utility of EMG for PLFs. The risk of neurological complications following PLF in the absence of spinal deformity is low and the routine use of EMG for PLF may not decrease the risk. Level of Evidence: 4