Miguel A. Pelton

Epidemiological trends in cervical spine surgery for degenerative diseases between 2002 and 2009.

Study Design. Retrospective analysis of a population-based database. Objective. To investigate national epidemiological trends of cervical spine surgical procedures from 2002–2009. Summary of Background Data. Anterior cervical fusion (ACF), posterior cervical fusion (PCF), and posterior cervical decompression (PCD) are procedures routinely performed for cervical degenerative pathology. Studies regarding epidemiological trends of these procedures is currently lacking in the literature. Methods. Data from the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project was obtained for each year between 2002 and 2009. Patients undergoing ACF, PCF, and PCD for the diagnosis of cervical radiculopathy and myelopathy were identified. Demographics, costs, and mortality were assessed in the surgical subgroups. A P value of 0.001 was used to denote significance. Results. An estimated 1,323,979 cervical spine surgical procedures were performed between 2002 and 2009. There was a significant upward trend in the mean age of patients undergoing cervical spine surgery during this time period. ACF and PCF cohorts demonstrated statistically significant increases in comorbidities and costs from 2002–2009. The PCF group had the greatest mortality, comorbidities, costs, and longest hospitalizations compared with ACF and PCF cohorts across all time periods. Conclusion. Our study demonstrates that cervical spine surgical procedures have increased between 2002 and 2009 (P = 0.001). The primary increase in volume is due to the increasing number of ACFs. Despite older patients with more comorbidities undergoing ACF and PCF procedures, mortality has not changed. However, this patient population trended significant increases in costs during this time period. We hypothesize that these increased costs are due to an increased comorbidity burden in patients undergoing ACF or PCF. Results of this study can be used to set benchmarks for future epidemiological investigations in cervical spine surgery. Level of Evidence: 4

The incidence and mortality of thromboembolic events in lumbar spine surgery.

Study Design. Retrospective database analysis. Objective. A population-based database was analyzed to identify the incidence, risk factors, and mortality associated with thromboembolic events after lumbar spine surgery. Summary of Background Data. Pulmonary embolism (PE) and deep vein thrombosis (DVT) are potential complications that may occur after orthopedic procedures. The incidence of these complications is not well characterized after lumbar spine surgery. Methods. Data from the Nationwide Inpatient Sample was obtained from 2002–2009. Patients undergoing lumbar decompression (LD), or lumbar fusion (LF) for degenerative conditions were identified. Acute PE and DVT incidences and mortality rates were calculated. Comorbidities were calculated using a modified Charlson Comorbidity Index. Statistical analysis was performed using the Student t test for discrete variables and &khgr;2 test for categorical data. Logistic regression was used to identify independent predictors of thromboembolic events. A P value of less than or equal to 0.0005 was used to denote statistical significance. Results. A total 578,457 LDs and LFs were identified from 2002–2009. DVT incidences were 2.4 and 4.3 per 1000 cases in the LD and LF groups, respectively. PE incidences were 1.0 and 2.6 per 1000 cases in the LD and LF groups, respectively. Patients who had undergone LF with thromboembolic events were younger, had fewer comorbidities, and incurred greater costs than patients who had undergone LD. Statistically significant predictors of DVT were pulmonary circulation disorders, coagulopathy, fluid/electrolyte disorders, anemia, obesity, teaching hospital status, and larger hospitals. Predictors for the development of PE were pulmonary circulation disorders, fluid/electrolyte disorders, anemia, black ethnicity and teaching hospital status. Conclusion. Patients undergoing LD or LF are at inherent risk of thromboembolic events. DVT and PE are more common after LF procedures. Preoperative pulmonary circulation disorders, fluid/electrolyte disorders, deficiency anemia, and teaching hospital status were significant risk factors for developing both DVT and PE. Preventive measures in patients at risk may decrease the incidence of thromboembolic events. Level of Evidence: 4

Factors affecting reoperations after anterior cervical discectomy and fusion within and outside of a Federal Drug Administration investigational device exemption cervical disc replacement trial

BACKGROUND CONTEXT The excellent clinical results of five US Federal Drug Administration (FDA) trials approved for cervical total disc replacement (TDR) (Prestige [Medtronic Sofamor Danek, Memphis, TN, USA], Bryan [Medtronic Sofamor Danek], ProDisc-C [Synthes, West Chester, PA, USA], Kineflex|C [SpinalMotion, Mountain View, CA, USA], and Mobi-C [LDR Spine, Austin, TX, USA]) have recently been published. In these prospective randomized studies, superiority or equivalency of TDR was claimed, citing an 8.7% (23/265), 9.5% (21/221), 8.5% (9/106), 12.2% (14/115), and 6.2% (5/81) (mean = 9.02%) rate of additional related cervical surgical procedures within 2 years in control anterior cervical discectomy and fusion (ACDF) patients, respectively, compared with 1.8% (5/276), 5.8% (14/242), 1.9% (2/103), 11% (15/136), and 1.2% (2/164) (mean = 4.34%) in patients receiving the cervical TDR. The rate of reoperation within 2 years after ACDF seems unusually high. PURPOSE To assess the rate of and specific indications for early reoperation after ACDF in a cohort of patients receiving the ACDF as part of their customary care. These results are contrasted with similar patients receiving ACDF as the control arm of five FDA investigational device exemption (IDE) studies. STUDY DESIGN Multisurgeon retrospective clinical series from a single institution. PATIENT SAMPLE One hundred seventy-six patients with spondylotic radiculopathy or myelopathy underwent ACDF by three surgeons between 2001 and 2005 as part of their clinical practices. All patients had at least 2 years of follow-up with final follow-up within 6 months of completion of this study. OUTCOME MEASURES Cervical reoperation rates at 2-year follow-up and at 3.5-year follow-up. METHODS Review of medical records and telephone conversations were completed to determine the number of patients who had undergone a revision cervical procedure. RESULTS At final follow-up, complete data were available for 159 ACDF patients. Of the 48 patients who underwent single-level ACDF and met criteria for inclusion in the IDE studies, one patient (2.1%) required additional surgery (adjacent-segment degeneration) within 2 years, the duration of follow-up of the five published IDE studies. Of the 159 patients who received single or multilevel ACDF at a mean follow-up of 3.5 years, 12 patients (7.6%) had undergone revision cervical surgery, with three patients (1.9%) undergoing same-level revisions (posterior fusion) and nine patients (5.7%) undergoing adjacent anterior level fusions. Patients who underwent revision same-level surgery typically had the intervention within the first year (mean, 11 months), whereas those requiring adjacent-level fusions typically had surgery later (mean, 29 months). CONCLUSIONS The present study identifies a 2.1% rate of repeat surgery within 2 years of a single-level ACDF performed during routine clinical practice, which is lower than that reported in the control arm of the Prestige, ProDisc-C, Bryan, Kineflex|C, and Mobi-C FDA trials (mean=9%). Even with longer follow-up including multilevel cases, our reoperation rate (7.6%) compared favorably with the IDE rates. This discrepancy may reflect different thresholds for reoperation in the control arm of a device IDE study compared with routine clinical practice. Additionally, patients enrolled in the single-level-only IDE trial may have received multilevel procedures outside of the study. This factor could result in a higher rate of subsequent surgeries at adjacent levels not addressed at the index procedure. These data suggest that we need to better understand factors driving treatment and, in particular, decisions to reoperate both in and outside of a device trial.

A perioperative cost analysis comparing single-level minimally invasive and open transforaminal lumbar interbody fusion

BACKGROUND CONTEXT Emerging literature suggests superior clinical short- and long-term outcomes of MIS (minimally invasive surgery) TLIFs (transforaminal lumbar interbody fusion) versus open fusions. Few studies to date have analyzed the cost differences between the two techniques and their relationship to acute clinical outcomes. PURPOSE The purpose of the study was to determine the differences in hospitalization costs and payments for patients treated with primary single-level MIS versus open TLIF. The impact of clinical outcomes and their contribution to financial differences was explored as well. STUDY DESIGN/SETTING This study was a nonrandomized, nonblinded prospective review. PATIENT SAMPLE Sixty-six consecutive patients undergoing a single-level TLIF (open/MIS) were analyzed (33 open, 33 MIS). Patients in either cohort (MIS/open) were matched based on race, sex, age, smoking status, medical comorbidities (Charlson Comorbidity index), payer, and diagnosis. Every patient in the study had a diagnosis of either degenerative disc disease or spondylolisthesis and stenosis. OUTCOME MEASURES Operative time (minutes), length of stay (LOS, days), estimated blood loss (EBL, mL), anesthesia time (minutes), Visual Analog Scale (VAS) scores, and hospital cost/payment amount were assessed. METHODS The MIS and open TLIF groups were compared based on clinical outcomes measures and hospital cost/payment data using SPSS version 20.0 for statistical analysis. The two groups were compared using bivariate chi-squared analysis. Mann-Whitney tests were used for non-normal distributed data. Effect size estimate was calculated with the Cohen d statistic and the r statistic with a 95% confidence interval. RESULTS Average surgical time was shorter for the MIS than the open TLIF group (115.8 minutes vs. 186.0 minutes respectively; p=.001). Length of stay was also reduced for the MIS versus the open group (2.3 days vs. 2.9 days, respectively; p=.018). Average anesthesia time and EBL were also lower in the MIS group (p<.001). VAS scores decreased for both groups, although these scores were significantly lower for the MIS group (p<.001). Financial analysis demonstrated lower total hospital direct costs (blood, imaging, implant, laboratory, pharmacy, physical therapy/occupational therapy/speech, room and board) in the MIS versus the open group (

A comparison of perioperative costs and outcomes in patients with and without workers' compensation claims treated with minimally invasive or open transforaminal lumbar interbody fusion.

19,512 vs.

Clinical sequelae after rhBMP-2 use in a minimally invasive transforaminal lumbar interbody fusion

23,550, p<.001). Implant costs were similar (p=.686) in both groups, although these accounted for about two-thirds of the hospital direct costs in the MIS cohort (

Outcomes of cervical spine surgery in teaching and non-teaching hospitals.

13,764) and half of these costs (

Prospective, Randomized, Controlled Trial of Silicate-substituted Calcium Phosphate versus rhbmp-2 in a Minimally Invasive Transforaminal Lumbar Interbody Fusion

13,778) in the open group. Hospital payments were

Predictive factors of hospital stay in patients undergoing minimally invasive transforaminal lumbar interbody fusion and instrumentation.

6,248 higher for open TLIF patients compared with the MIS group (p=.267). CONCLUSIONS MIS TLIF technique demonstrated significant reductions of operative time, LOS, anesthesia time, VAS scores, and EBL compared with the open technique. This reduction in perioperative parameters translated into lower total hospital costs over a 60-day perioperative period. Although hospital reimbursements appear higher in the open group over the MIS group, shorter surgical times and LOS days in the MIS technique provide opportunities for hospitals to reduce utilization of resources and to increase surgical case volume.

Subaxial Cervical and Cervicothoracic Fixation Techniques—Indications, Techniques, and Outcomes

Study Design. A nonrandomized, nonblinded prospective review. Objective. To analyze intraoperative, immediate postoperative, and financial outcomes in workers compensation (WC) and non-WC patients undergoing either an open or a minimally invasive surgery (MIS) transforaminal lumbar interbody fusion (TLIF). Summary of Background Data. Few studies have analyzed outcomes in a WC population of MIS TLIFs. Methods. A total of 66 consecutive patients undergoing a single-level TLIF (open/MIS) were analyzed (33 open and 33 MIS). Twenty-four total WC patients were identified (11 MIS and 13 open). Patients in either cohort (MIS/open) were matched according to insurance status (WC) and medical comorbidities (Charleston disability index). Every patient in this study had a diagnosis of either degenerative disc disease or spondylolisthesis and stenosis. Operative time (min), length of stay (d), estimated blood loss (mL), anesthesia time (min), visual analogue scale scores, and hospital cost/payment amount were assessed (MIS/open and work-comp versus non-work comp). Results. There were no statistically significant differences between MIS WC and non-WC TLIFs with respect to surgical time, length of stay, estimated blood loss, visual analogue scale scores, and anesthesia time. There were no statistically significant differences between open WC and non-WC TLIF patients in all of the same above-mentioned parameters. There were significant differences between MIS (WC and non-WC) and open (WC and non-WC) TLIFs in clinical outcomes. There were statistically significant differences in total costs amounts between WC MIS TLIF and WC open TLIF (