Faculty Bibliography

BACKGROUND CONTEXT: Intraoperative CT image-guided navigation (IGN) and robotic assistance have been increasingly implemented during spine surgery to improve accuracy in pedicle screw positioning. However, studies have shown that they increase operative time and ionizing radiation exposure, and it remains controversial whether they improve patient outcomes. PURPOSE: Assess use of IGN and robotic assistance in posterior lumbar surgery and their relationship with patient radiation exposure and perioperative outcomes. STUDY DESIGN/SETTING: Retrospective cohort study at single institution. PATIENT SAMPLE: A total of 165 patients undergoing 1- or 2-level posterior spinal fusion, with or without TLIF. OUTCOME MEASURES: Preoperative CT scan utilization and radiation dose, intraoperative radiation dose (fluoroscopy and/or CT) and total-procedure radiation dose (sum of preoperative CT and intraoperative radiation doses), levels fused, operative time, estimated blood loss (EBL), length of stay (LOS), postoperative complications.
METHOD(S): Patients >=18 years old undergoing 1- or 2-level posterior spinal fusion, with or without TLIF, in a 12-month period included. Chart review performed for pre- and intraoperative data on radiation dose and perioperative outcomes. All radiation doses quantified in milli-Grays (mGy). Univariate analysis and multivariate logistic regression analysis for categorical variables and one-way ANOVA for continuous variables utilized, with significance set at p<0.05.
RESULT(S): A total of 165 patients (51.83% F, 59.13+/-13.18yrs, BMI 29.43+/-6.72, Charlson comorbidity index [CCI] 1.20+/-1.56) were assessed: 12 IGN, 62 robotic, 56 open, 35 MIS without IGN/robotics. Lower proportion of women in open and MIS group (66.67% F IGN, 64.52% robotic, 38.18% open, 45.71% MIS, p=0.010). Younger patients in MIS group (63.42 yrs IGN, 61.74 robotic, 60.63 open, 50.63 MIS, p<0.001). MIS group had lowest mean posterior levels fused (1.42 IGN, 1.27 robotic, 1.32 open, 1.06 MIS, p=0.015). Total-procedure radiation (50.21mGy IGN, 59.84 robotic, 22.56 open, 82.02 MIS), total-procedure radiation/level fused (41.88mGy IGN, 51.18 robotic, 18.56 open, 79.41 MIS) and intraop radiation (44.69mGy IGN, 44.85 robotic, 14.81 open, 80.28 MIS) were lowest in the open group and highest in the MIS group compared to IGN and robotic (all p<0.001). A higher proportion of robotic and lower proportion MIS patients had preop CT (25% IGN, 82.26% robotic, 37.5% open, 8.57% MIS, p<0.001). EBL (441.67mL IGN, 380.24 robotic, 355.36 open, 162.14 MIS, p=0.002) and LOS (4.75 days IGN, 3.89 robotic, 3.89 open, 2.83 MIS, p=0.039) were lowest in the MIS group. Highest operative time for IGN patients (303.5 min vs 264.85 robotic, 229.91 open, 213.43 MIS p<0.001). No differences in BMI, CCI, postoperative complications (p=0.313, 0.051, 0.644, respectively).
CONCLUSION(S): IGN and robotic assistance in posterior lumbar fusion were associated with higher intraoperative and total-procedure radiation exposure than open cases without IGN/robotics, but significantly less than MIS without IGN/robotics, without differences in perioperative outcomes. While MIS procedures reported highest radiation exposure to patient, of more concern is that the proportion of total radiation dose applied to surgeon would also be considerably higher in MIS group. FDA DEVICE/DRUG STATUS: Brainlab Airo Mobile Intraoperative CT scanner (Approved for this indication).
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BACKGROUND CONTEXT: The efficacy of surgical intervention for central cord syndrome (CCS) is shown in the literature; however, it is unclear whether disparities in patient presentation and treatment exist between those who initially undergo operative treatment and those who delay operative treatment. PURPOSE: In a population of CCS patients, assess disparities in presentation and treatment between those undergoing immediate surgery and those who delay operative treatment. STUDY DESIGN/SETTING: Retrospective analysis of New York State Inpatient Database years 2004-2013. PATIENT SAMPLE: A total of 1,301 CCS patients (ICD-9 codes 952.03, 952.08, 952.13, 952.18). OUTCOME MEASURES: Time to surgery, length of stay (LOS).
METHOD(S): Patient-specific linkage codes allowed longitudinal tracking of inpatient stays within the study period. Demographics, comorbidities (Charlson Comorbidity Index [CCI]), complications, and surgical factors, including Mirza invasiveness score, were compared between CCS patients that initially underwent surgery (Initial) and patients that delayed operative treatment (Delayed) using Chi-squared tests and independent samples t-tests as appropriate. Similar tests assessed differences in demographics and comorbidity burden between nonoperative patients and surgical crossover patients.
RESULT(S): Included: 1,301 CCS patients (62+/-16 yrs, 27% female). Follow-up rate was 67.3%; mean follow-up time was 515+/-707 days. By level of CCS injury, 61.0% of patients were injured between C1 and C4, 59.2% between C5-C7, 1.0% between T1-T6, and 0.6% between T7-T12. Overall, 800 (61%) patients underwent surgical treatment (procedural breakdown: 80% fusion, 59% decompression, including 38% discectomy and 23% other decompression of the spinal canal). Of the surgical patients, 621 (78%) had surgery at first recorded hospital visit, while 179 (22%) experienced a delay before surgical treatment. For patients that delayed treatment, mean time to surgery was 203+/-358 days. Initial and Delayed patients did not differ in sex (p=0.109) or CCI (p=0.894), though Initial patients were younger than Delayed (60+/-15 yrs vs 63+/-13, p=0.016) and had lower rates of diabetes and valvular disease (both p<0.04). Initial patients underwent more invasive procedures than Delayed (5.1+/-2.6 vs 4.3+/-3.2, p=0.003), including higher rates of fusion (84% vs 71%, p<0.001), but not decompression: overall (59% vs 60%, p=0.816), discectomy (39% vs 35%, p=0.306), other canal decompression (22% vs 27%, p=0.175). LOS was longer for Initial patients (16+/-20 days vs 7+/-10, p<0.001), but complication rates did not differ (all p>0.05). Patients who delayed operative treatment did not differ from nonop patients in age (63+/-13 vs 63+/-17, p=0.802) or CCI (1.04+/-1.49 vs 1.06+/-1.49, p=0.923); however, Delayed patients had higher rates of diabetes (26% vs 18%, p=0.037), neurologic disorders (7% vs 1%, p<0.001), and valvular disease (6% vs 2%, p=0.026) than patients that remained nonoperative.
CONCLUSION(S): Although patients managed with initial surgical treatment of CCS had longer hospital stays and were treated with more invasive procedures, perioperative complications did not differ. Twenty-two percent of CCS patients crossed over from nonoperative to operative treatment, with a mean time to crossover of 203 days. Patients who crossed over to operative care were more comorbid than patients who remained nonoperative, indicating comorbidity burden may play a role in the decision to operate. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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Fusion and rigid instrumentation have been the mainstay for the surgical treatment of degenerative diseases of the spine for many years. Dynamic stabilization provides a theoretical advantage of decreased biomechanical stress on adjacent spinal segments and decreased fatigue failure of implants. Artificial discs provide an alternative treatment and have been well-studied in the literature. Another technology that is currently used in Europe but rarely in the USA is flexible rods attached to pedicle screws instead of rigid rods or bone fusion. We performed a literature review of the current systems of flexible rod stabilization, while also considering range of motion, loading characteristics, and infection rates.

STUDY-DESIGN: Secondary analysis of data from a prospective multicenter observational study. OBJECTIVE: To evaluate the occurrence of surgical site infection (SSI) in patients with and without intrawound vancomycin application controlling for confounding factors associated with higher SSI after elective spine surgery. SUMMARY OF BACKGROUND DATA: SSI is a morbid and expensive complication associated with spine surgery. The application of intrawound vancomycin is rapidly emerging as a solution to reduce SSI following spine surgery. The impact of intrawound vancomycin has not been systematically studied in a well-designed multicenter study. METHODS: Patients undergoing elective spine surgery over a period of four-years at seven spine surgery centers across the United States were included in the study. Patients were dichotomized based on whether intrawound vancomycin was applied. Outcomes were occurrence of SSI within postoperative 30-days and SSI that required return to the operating room (OR). Multivariable random effect log-binomial regression analyses were conducted to determine the relative risk of having a SSI and a SSI with return to OR. RESULTS: A total of 2056 were included in the analysis. Intrawound vancomycin was utilized in 47% (n = 966) of patients. The prevalence of SSI was higher in patients with no vancomycin use (5.1%) compared to those with use of intrawound vancomycin (2.2%). The risk of SSI was higher in patients in whom intrawound vancomycin was not used (RR-2.5,p < 0.001), increased number of levels exposed (RR-1.1,p = 0.01), and those admitted postoperatively to intensive care unit (ICU) (RR-2.1,p = 0.005). Patients in whom intrawound vancomycin was not used (RR-5.9, p < 0.001), increased number of levels were exposed (RR-1.1,p = 0.001) and postoperative ICU admission (RR-3.3,p < 0.001) were significant risk factors for SSI requiring a return to the OR CONCLUSION.: The intrawound application of vancomycin after posterior approach spine surgery was associated with reduced risk of SSI and return to OR associated with SSI. LEVEL OF EVIDENCE: 2.

INTRODUCTION: Orthopaedic care is shifting to alternative payment models. We examined whether New York University Langone Medical Center achieved savings under the Centers for Medicare and Medicaid Services Bundled Payments for Care Improvement initiative. METHODS: This study was a difference-in-differences study of Medicare fee-for-service patients hospitalized from April 2011 to June 2012 and October 2013 to December 2014 for lower extremity joint arthroplasty, cardiac valve procedures, or spine surgery (intervention groups), or for congestive heart failure, major bowel procedures, medical peripheral vascular disorders, medical noninfectious orthopaedic care, or stroke (control group). We examined total episode costs and costs by service category. RESULTS: We included 2,940 intervention episodes and 1,474 control episodes. Relative to the trend in the control group, lower extremity joint arthroplasty episodes achieved the greatest savings: adjusted average episode cost during the intervention period decreased by $3,017 (95% confidence interval [CI], -$6,066 to $31). For cardiac procedures, the adjusted average episode cost decreased by $2,999 (95% CI, -$8,103 to $2,105), and for spinal fusion, it increased by $8,291 (95% CI, $2,879 to $13,703). Savings were driven predominantly by shifting postdischarge care from inpatient rehabilitation facilities to home. Spinal fusion index admission costs increased because of changes in surgical technique. DISCUSSION: Under bundled payment, New York University Langone Medical Center decreased total episode costs in patients undergoing lower extremity joint arthroplasty. For patients undergoing cardiac valve procedures, evidence of savings was not as strong, and for patients undergoing spinal fusion, total episode costs increased. For all three conditions, the proportion of patients referred to inpatient rehabilitation facilities upon discharge decreased. These changes were not associated with an increase in index hospital length of stay or readmission rate. CONCLUSION: Opportunities for savings under bundled payment may be greater for lower extremity joint arthroplasty than for other conditions.

OBJECTIVE: This is a nationwide query into surgical management techniques for tethered cord syndrome, focusing on patient demographic, hospital characteristics, and treatment outcomes. Our hypothesis is that detethering vs. fusion for TCS results in different in-hospital complications. MATERIALS AND METHODS: Retrospective review of the Nationwide Inpatient Sample 2001-2010. Inclusion: TCS discharges undergoing detethering or fusion. Sub-analysis compared TCS cases by age (pediatric [