Timothy Y. Wang

Rates of anterior cervical discectomy and fusion after initial posterior cervical foraminotomy

BACKGROUND CONTEXT In select patients, posterior cervical foraminotomy (PCF) and anterior cervical discectomy and fusion (ACDF) result in similar clinical outcomes when used to treat cervical radiculopathy. Nonetheless, ACDF is performed more frequently, in part because of surgeon perception that PCF requires operative revisions more frequently. The present study investigates the rate of ACDF reoperation at the index level after initial PCF. PURPOSE To determine the rate of ACDF after initial PCF and to further describe any patient characteristics or preoperative or operative data that increase the rate of reoperation after PCF. STUDY DESIGN Retrospective chart review. METHODS Demographic, operative, and reoperation information was collected from the electronic medical records for all patients who underwent PCF at one institution between 2004 and 2011. All patients were subsequently contacted by telephone to identify postoperative complications and more conclusively determine whether any revision operation was performed at the index level. RESULTS One hundred seventy-eight patients who underwent a PCF were reviewed, with an average follow-up of 31.7 months. Nine (5%) patients underwent an ACDF revision operation at the index level. The reason for reoperation in these patients included cervical radiculopathy, foraminal stenosis, disc herniation, and cervical spondylosis. Patients who subsequently underwent ACDF at the index level were significantly younger (25 vs. 35 years, p=.03), had lower body mass index (25 vs. 29, p=.01), and more likely to take anxiolytic (56% vs. 22%, p=.04) or antidepressant medication (67% vs. 27%, p=.02), compared with those that did not have a revision operation. CONCLUSIONS This is the first study to determine conversion to ACDF after PCF. The present study demonstrates that PCF is associated with a low reoperation rate, similar to the historical reoperation for ACDF. Accordingly, spine surgeons can operate via a PCF approach without a significant increased risk for ACDF revision surgery at the index level.

A Systematic Review of Lumbar Fusion Rates With and Without the Use of rhBMP-2.

Study Design. Systematic review. Objective. To evaluate literature comparing fusion rates in anterior lumbar interbody fusion (ALIF), posterior lumbar interbody/transforaminal lumbar interbody fusion (PLIF/TLIF), and posterolateral lumbar fusion (PLF) with and without recombinant human bone morphogenetic protein-2 (rhBMP-2). Summary of Background Data. rhBMP-2 is used for the FDA-approved indication of single-level ALIF with LT-Cage and off-label for PLIF/TLIF, and PLF. Due to recent controversies, it is essential to evaluate the literature for its effects on fusion rates to evaluate whether benefits outweigh potential complications. Methods. A Medline search was performed of clinical studies published between May 2000 and May 2012 comparing fusion rates after ALIF, PLIF/TLIF, and PLF surgery with versus without rhBMP-2. Only studies with a control arm were reviewed. Results. 16 studies were reviewed (1794 patients, 995 treated with rhBMP-2 and 799 without). 5 of 5 studies for PLIF/TLIF (including 301 of 301 patients), 1 of 4 for ALIF (including 279 of 589 patients), and 3 of 7 for PLF (including 272 of 904 patients) reported no significant improvement in fusion rates with rhBMP-2 compared with those without rhBMP-2 at longest follow-up investigated. Average fusion rate 24 months after surgery was 97.8% for ALIF (n = 316), 95.7% for PLIF/TLIF (n = 141), and 93.6% for PLF (n = 422) with rhBMP-2 and 88.2% (n = 228), 89.5% (n = 86), and 83.1% (n = 372) without rhBMP-2, for ALIF, PLIF/TLIF, and PLF, respectively. Odds ratio of fusion were calculated as 7.08 (95% CI: 1.54–32.7) in ALIF, 1.98 (95% CI: 0.39–10.1) in PLIF/TLIF, and 3.06 (95% CI: 1.61–5.80) in PLF with rhBMP-2 as compared with without rhBMP-2. Conclusion. Although numerous studies did not show statistically significant improvement in fusion rates with rhBMP-2 use, analysis of combined studies revealed significant improvement in fusion rate with rhBMP-2 in ALIF and PLF patients. Notably, even when pooling data from several studies, rhBMP-2 did not result in statistically significantly improved fusion rates in PLIF/TLIF. However, heterogeneity of rhBMP-2 dosing, surgical techniques, and quality of papers reviewed may limit the validity of conclusions drawn. Level of Evidence: 4

Risk Assessment And Characterization of 30-Day Perioperative Myocardial Infarction Following Spine Surgery: A Retrospective Analysis of 1346 Consecutive Adult Patients.

Study Design. A retrospective review. Objective. The aim of the study was to perform a risk assessment of 30-day perioperative myocardial infarction (MI) for spine surgery patients. Summary of Background Data. There is an increased emphasis to reduce complications and improve outcomes after spinal surgery. One of the more devastating perioperative complications of spinal surgery is MI. Methods. We evaluated all medical records of 1346 consecutive patients who underwent spinal surgery at a single institution from 2008 to 2010 for incidence of MI within 30 days of surgery and documented all demographic, preoperative, and operative variables. Associations between postoperative MI and individual risk factors were determined using logistic regression analysis. Patients were stratified into emergent and elective groups and a similar analysis was performed. Results. Overall, 22 patients (1.6%) had 30-day perioperative MI, 14 patients (1.2%) undergoing elective surgery, and 8 patients (4.2%) after emergent surgery (P = 0.047). Three (13.6%) patients experienced 30-day mortality and an additional 3 (13.6%) patients experienced mortality within 1 year. Multivariate logistic regression determined that age more than 65 years, atrial fibrillation, hypertension, prior MI, anticoagulant use, low albumin, length of stay more than 7 days, intraoperative transfusion, trauma etiology, baseline creatinine more than 1 mg/dL, and at least 2 levels of spinal fusion were predictive of postoperative MI. For patients undergoing emergent surgery, age more than 65 years was associated with an increased risk of postoperative MI. When stratified by elective surgery, we found that age more than 65, postoperative stay more than 7 days, intraoperative blood transfusion, baseline creatinine more than 1 mg/dL, and fusion of more than 1 level were associated with an increased risk of MI. Conclusion. The present study demonstrates a low incidence of MI after elective surgery with a higher incidence after emergent spine surgery and identifies patient factors predictive of postoperative MI. Level of Evidence: 3

315 Race as a Predictor of Postoperative Hospital Readmission After Spine Surgery.

INTRODUCTION Hospital readmission after surgery results in a substantial economic burden, and several recent studies have investigated the impact of race and ethnicity on hospital readmission rates, with the goal to identify hospitals and patients with high readmission risk. METHODS This single-institution, retrospective cohort study assesses the impact of race, along with preoperative and intraoperative risk factors, on 30-day readmission rates following spinal surgery. A total of 1346 consecutive adult patients who underwent anterior and/or posterior spinal surgery from 2008 to 2010 for degenerative and deformity causes, as well as for higher-risk causes, including traumatic and neoplastic etiologies, were included in the study. Clinical variables included age, demographics, surgical etiology, intraoperative technique, and other comorbidities known to be associated with postoperative complication. RESULTS A total of 1346 patients (654 male, 692 female) were included in the study. With the use of multivariate logistic regression, black patients were found to have over twice the odds of readmission (odds ratio [OR], 2.20; 95% confidence interval [CI],: 1.04-4.64), and patients with total length of stay of 7 or more days had nearly 5 times the odds of readmission (OR, 4.73; 95% CI, 1.72-12.98). Conversely, patients who underwent cervical surgery were found to have lower odds of readmission (OR, 0.27; 95% CI, 0.08-0.91). CONCLUSION Within the context of the ongoing national goal of reducing hospital readmission, our study demonstrated that race and length of hospital stay influence the incidence of 30-day readmission rates after spinal surgery. Studies such as ours will aid in identifying patients with postoperative readmission risk and help elucidate the underlying factors that may be contributing to disparities in readmission after surgery.

Clinical outcomes following surgical management of coexistent cervical stenosis and multiple sclerosis: a cohort-controlled analysis

BACKGROUND CONTEXT The presentation of myelopathy in patients with the concomitant diagnosis of cervical stenosis (CS) and multiple sclerosis (MS) complicates both diagnosis and treatment because of the similarities of presentation and disease progression. There are only a few published case series that examine this unique patient population. PURPOSE To define the demographic features and presenting symptoms of patients with both MS and CS and to investigate the immediate and long-term outcomes of surgery in patients with MS and CS. STUDY DESIGN/SETTING Matched cohort-controlled retrospective review of 77 surgical patients in the MS group and 77 surgical patients in the control group. Outcome measures were immediate and long-term postoperative neck pain, radiculopathy, and myelopathy; Nurick Disability and modified Japanese Orthopaedic Association scores were collected as well. METHODS Retrospective review was performed for all patients presenting at one institution between January 1996 and July 2011 with coexisting diagnoses of MS and CS who had presenting symptoms of myelopathy and who then underwent cervical decompression surgery. Each study patient was individually matched to a control patient of the same gender and age that did not have MS, but that did have cervical spondylotic myelopathy or myeloradiculopathy. Each control patient underwent the same surgical procedure within the same year. RESULTS A total of 154 patients were reviewed, including 77 MS patients and 77 control patients, for an average follow-up of 58 months and 49 months, respectively. Patients in the control group were more likely to have preoperative neck pain (78% vs. 47%; p=.0001) and preoperative radiculopathy (90% vs. 75%; p=.03) than their counterparts in the MS group. Patients in the MS group had a significantly lower rate of postoperative resolution of myelopathic symptoms in both the short-term (39% in the MS group did not improve vs. 23% in the control group; p=.04) and the long-term (44% in the MS group did not improve vs. 19% in the control group; p=.004). Preoperative myelopathy scores were worse for the MS cohort as compared with the control cohort (1.8 vs. 1.2 in the Nurick scale, p<.0001; 13.7 vs. 15.0 in the modified Japanese Orthopaedic Association scale, p=.002). This difference in scores became even greater at the last follow-up visit with Nurick scores of 2.4 versus 0.9 (p<.0001) and modified Japanese Orthopaedic Association scores of 16.3 versus 12.4 (p<.0001) for the MS and control patients, respectively. CONCLUSIONS Myelopathic patients with coexisting MS and CS improve after surgery, although at a lower rate and to a lesser degree than those without MS. Therefore, surgery should be considered for these patients. MS patients should be informed that myelopathy symptoms are less likely to be alleviated completely or may only be alleviated temporarily because of progression of MS and that surgery can help alleviate neck pain and radicular symptoms.

Post-operative delirium is an independent predictor of 30-day hospital readmission after spine surgery in the elderly (≥65 years old): A study of 453 consecutive elderly spine surgery patients

In the last decade, costs of U.S. healthcare expenditures have been soaring, with billions of dollars spent on hospital readmissions. Identifying causes and risk factors can reduce soaring readmission rates and help lower healthcare costs. The aim of this is to determine if post-operative delirium in the elderly is an independent risk factor for 30-day hospital readmission after spine surgery. The medical records of 453 consecutive elderly (≥65years old) patients undergoing spine surgery at Duke University Medical Center from 2008 to 2010 were reviewed. We identified 17 (3.75%) patients who experienced post-operative delirium according to DSM-V criteria. Patient demographics, comorbidities, and post-operative complication rates were collected for each patient. Elderly patients experiencing post-operative delirium had an increased length of hospital stay (10.47days vs. 5.70days, p=0.009). Complication rates were similar between the cohorts with the post-operative delirium patients having increased UTI and superficial surgical site infections. In total, 12.14% of patients were re-admitted within 30-days of discharge, with post-operative delirium patients experiencing approximately a 4-fold increase in 30-day readmission rates (Delirium: 41.18% vs. No Delirium: 11.01%, p=0.002). In a multivariate logistic regression analysis, post-operative delirium is an independent predictor of 30-day readmission after spine surgery in the elderly (p=0.03). Elderly patients experiencing post-operative delirium after spine surgery is an independent risk factor for unplanned readmission within 30-days of discharge. Preventable measures and early awareness of post-operative delirium in the elderly may help reduce readmission rates.

Impact of surgical site infection and surgical debridement on lumbar arthrodesis: A single-institution analysis of incidence and risk factors

This study identifies the rate of pseudarthrosis following surgical debridement for deep lumbar spine surgical site infection and identify associated risk factors. Patients who underwent index lumbar fusion surgery from 2013 to 2014 were included if they met the following criteria: 1) age >18years, 2) had debridement of deep lumbar SSI, and had 3) lumbar spine AP, lateral and flexion/extension X-rays and computed tomography (CT) at 12months or greater postoperatively. Criteria for fusion included 1) solid posterolateral, facet, or disk space bridging bone, 2) no translational or angular motion on flexion/extension X-rays, and 3) intact posterior hardware without evidence of screw lucency or breakage. Twenty-five patients (age 63.2±12.6years, 10 male) involving 58 spinal levels met inclusion criteria. They underwent fusion at a mean of 2.32 [range 1-4] spinal levels. Sixteen (64.0%) patients received interbody grafts at a total of 34 (58.6%) spinal levels. All underwent surgical debridement with removal of all non-incorporated posterior bone graft and devascularized tissue. At one-year postoperatively, (56%) patients and 30 (52%) spinal levels demonstrated radiographic evidence of successful fusion. Interbody cage during initial fusion was significantly associated with successful arthrodesis at follow-up (p=0.017). There is a high rate of pseudoarthrosis in 44% of patients (48% of levels) undergoing lumbar fusion surgery complicated by SSI requiring debridement. Use of interbody cage during initial fusion was significantly associated with higher rate of arthrodesis.

Bony Lateral Recess Stenosis and Other Radiographic Predictors of Failed Indirect Decompression via Extreme Lateral Interbody Fusion: Multi-Institutional Analysis of 101 Consecutive Spinal Levels

OBJECTIVE Although extreme lateral interbody fusion (XLIF) largely provides successful indirect decompression, some patients have recurrent same-level pain and functional disability. Identifying risk factors for this failure would facilitate better patient selection and improve outcomes. The aim of this study is to identify preoperative radiographic risk factors for failure of XLIF. METHODS Patients undergoing XLIF were prospectively enrolled by 3 surgeons at 3 separate institutions. Radiographic variables measured included (1) anterior and posterior disc height, (2) foramen height and area, (3) central canal diameter, (4) central canal area, (5) right and left subarticular diameters, (6) facet arthropathy grade, and (7) presence of bony lateral recess stenosis. Patients failed indirect decompression if Oswestry Disability Index (ODI) scores did not improve by 20 points or revision surgery was required within 6 months postoperatively. Univariate and multivariate analyses were performed to identify radiographic predictors of failure of indirect decompression. RESULTS Of the 45 patients (age 65.6 ± 10.5 years; 14 male) involving 101 spinal levels included in this study, 13 (29%) failed indirect decompression. From univariate analysis, these patients had significantly smaller central canal diameter, foraminal height, and disc height (P < 0.05). In multivariate analysis of these parameters and those trending toward significance, bony lateral recess stenosis was the only significant independent predictor for failure of indirect decompression (coefficient, 0.55 [0.24-0.85]; P < 0.001). CONCLUSIONS Bony lateral recess stenosis is an independent predictor for failure to achieve adequate spinal decompression via XLIF and thus may benefit from undergoing direct decompression.

Internally Randomized Control Trial of Radiation Exposure Using Ultra-low Radiation Imaging Versus Traditional C-arm Fluoroscopy for Patients Undergoing Single-level Minimally Invasive Transforaminal Lumbar Interbody Fusion.

Study Design. Randomized controlled trial. Objective. To compare radiation exposure between ultra-low radiation imaging (ULRI) with image enhancement and standard-dose fluoroscopy for patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). Summary of Background Data. Although the benefits of MIS are lauded by many, there is a significant amount of radiation exposure to surgeon and operating room personnel. Our goal with this work was to see if by using ultra-low dose radiation settings coupled with image enhancement, this exposure could be minimized. Methods. An institutional review board approved, prospective, internally randomized controlled trial was performed comparing ultra-low dose settings coupled with image enhancement software to conventional fluoroscopic imaging. In this study, each patient served as their own control, randomly assigning one side of MIS-TLIF for cannulation and K-wire placement using each imaging modality. Further, the case was also randomly divided into screw placement and cage placement/final images to allow further comparisons amongst patients. Radiation production from the C-arm fluoroscope and radiation exposure to all operating room personnel were recorded. Results. Twenty-four patients were randomly assigned to undergo a single level MIS-TLIF. In no case was low radiation imaging abandoned, and no patient had a neurologic decline or required hardware repositioning. Everyone in the operating room—the physician, scrub nurse, circulator, and anesthesiologist—all benefited with 61.6% to 83.5% reduction in radiation exposure during cannulation and K-wire placement to screw insertion aided by ULRI. In every case but the anesthesiologist dose, this was statistically significant (P < 0.05). This benefit required no additional time (P = 0.78 for K-wire placement). Conclusion. ULRI, when aided by image enhancement software, affords the ability for all parties in the operating room to substantially decrease their radiation exposure compared with standard-dose C-arm fluoroscopy without adding additional time or an increased complication rate. Level of Evidence: 2

Race as a predictor of postoperative hospital readmission after spine surgery

Hospital readmission after surgery results in a substantial economic burden, and several recent studies have investigated the impact of race and ethnicity on hospital readmission rates, with the goal to identify hospitals and patients with high readmission risk. This single-institution, retrospective cohort study assesses the impact of race, along with other risk factors, on 30-day readmission rates following spinal surgery. This study is a single-institution retrospective cohort study with accrual from January 1, 2008, to December 31, 2010. Inclusion criteria included adult patients who underwent anterior and/or posterior spinal surgery. The primary aim of this study was to assess the impact of patient race and other risk factors for postoperative hospital readmission within 30days following spine surgery. A total of 1346 patients (654 male, 692 female) were included in the study. Overall, 159 patients (11.8%) were readmitted in the 30days following their surgery. Multivariate logistic regression found significant risk factors for 30-day readmission, including Black race (OR: 2.20, C.I. 95% (1.04, 4.64)) and total length of stay greater than 7days (OR: 4.73, C.I. 95% (1.72, 12.98)). Cervical surgery was associated with decreased odds of readmission (OR: 0.27, C.I. 95% (0.08, 0.91)). Our study demonstrates that race and length of hospital stay influence the incidence of 30-day readmission rates after spinal surgery. Studies such as ours will aid in identifying patients with postoperative readmission risk and help elucidate the underlying factors that may be contributing to disparities in readmission after surgery.