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Symptomatic postoperative epidural hematomas are rare, with an incidence of 0.10% to 0.69%. Risk factors have varied in the literature, but multiple studies have reported advanced age, preoperative or postoperative coagulopathy, and multilevel laminectomy as risk factors for hematoma. The role of pharmacologic anticoagulation after spine surgery remains unclear, but multiple studies suggest it can be done safely with a low risk of epidural hematoma. Prophylactic suction drains have not been found to lower hematoma incidence. Most symptomatic postoperative epidural hematomas present within the first 24 to 48 hours after surgery but can present later. Diagnosis of a symptomatic hematoma requires correlation of clinical signs and symptoms with a compressive hematoma on MRI. Patients will usually first complain of a marked increase in axial pain, followed by radicular symptoms in the extremities, followed by motor weakness and sphincter dysfunction. An MRI should be obtained emergently, and if it confirms a compressive hematoma, surgical evacuation should be carried out as quickly as possible. The prognosis for neurologic improvement after evacuation depends on the time delay and the degree of neurologic impairment before evacuation.

Background Lumbar disc herniation (LDH) is a common problem. When surgical treatment is required, the intervention is typically decompression without fusion. Successful return-to-work (RTW) is a standard expectation with these limited procedures. Occasionally, the size or location of the disc herniation suggests the need for fusion, but the inability to RTW is a significant concern in these cases. The purpose of this study is to determine if the addition of lumbar fusion, as compared to decompression alone, will substantially diminish RTW in patients with lumbar disc herniation. Methods This is a longitudinal cohort study using prospectively collected data from the Quality and Outcomes Database (QOD). Patients with LDH, eligible to RTW (not retired, a student, or on disability) with complete 12-month follow-up data, were identified. Standard demographic and surgical variables, patient-reported outcomes (PROs), and RTW status at 3 and 12 months were collected. Results Of the 5062 patients identified, 4560 (90%) had decompression alone and 502 (10%) had a concurrent fusion. Age and gender were similar in the two groups. The fusion group had worse back pain (NRS 6.52 vs. 5.96) and less leg pain (6.31 vs. 7.01) at baseline compared to the no fusion group. Statistically significant improvement in all PROs was seen in both groups. RTW at 3 months post-op was seen in 85% of decompression cases and 66% of cases with supplemental fusion. At 12 months post-op, RTW increased to 93% and 82%, respectively. Conclusion The need for fusion in LDH cases is unusual, seen in only 10% of cases in this series. The addition of fusion decreased the RTW rate from 85 to 66% at 3 months and from 93 to 82% at 12 months post-op. While the difference is significant, the ultimate deterioration in RTW may be less than anticipated. A reasonable RTW rate can still be expected in the rare patient who requires fusion as part of their treatment for LDH.

Controversy exists regarding the ability of posterior (transforaminal) lumbar interbody fusion (PLIF/TLIF) to achieve lordosis. We hypothesized that an interbody device (IBD) designed for positioning in the anterior disc space produces greater lordosis than IBDs designed for straight-in positioning. The purpose of this study is to determine if using either an anterior-position or straight-in position IBD design were associated with successful achievement of postoperative lordosis.A consecutive series of patients undergoing a undergoing a single-level, posterior open midline (transforaminal) lumbar interbody fusion procedure for degenerative spine conditions during a time period when the two types of interbody devices were being used at surgeon discretion were identified from a multi-surgeon academic training center. Patient demographics and radiographic measures including surgical level lordosis (SLL), anterior disc height, middle disc height, posterior disc height, IBD height, and IBD insertion depth were measured on preop, immediate postop, and one-year postop standing radiographs using PACS. Group comparison and regression analysis were performed using SPSS.Sixty-one patients were included (n=37 anterior, n=34 straight-in). Mean age was 59.8±8.7 years, 32 (52%) were female. There was no difference between IBD type (anterior vs. straight-in) for mean Pre-op SLL (19±7° vs. 20±6°, p=0.7), Post-op SLL (21±5° vs 21±6°, p=0.5), or Change in SLL (2±4° vs. 1±5°, p=0.2). Regression analysis showed that Pre-op SLL was the only variable associated with Change in SLL (Beta = negative 0.48, p=0.000). While the mean Change in SLL could be considered clinically insignificant, there was wide variability: from a loss of 9° to a gain of 13°. Gain of lordosis5° only occurred when Pre-op SLL was21°, and loss of lordosis5° only occurred when Pre-op SLL was21°.While group averages showed an insignificant change in segmental lordosis following a posterior (transforaminal) interbody fusion regardless of interbody device type, pre-operative lordosis was correlated with a clinically significant change in segmental lordosis. Preoperative hypolordotic discs were more likely to gain significant lordosis, while preoperative hyperlordotic discs were more likely to lose significant lordosis. Surgeon awareness of this tendency can help guide surgical planning and technique.

BACKGROUND: The opioid epidemic is at epic proportions currently in the United States. Exposure to opioids for surgery and subsequent postoperative pain management is a known risk factor for opioid dependence. In addition, opioids can have a negative impact on multiple aspects including clinical outcomes, length of hospital stay, and overall cost of care. Thus, the greatest effort to reduce perioperative opioid use is necessary and a multimodal pain control (MMPC) has been gaining popularity. However, its efficacy in spine surgery is not well known. We aimed to evaluate the efficacy of a MMPC protocol in patients undergoing lumbar single-level anterior lumbar interbody fusion (ALIF). METHODS: This is a retrospective comparative study. From a prospective, single-surgeon, surgical database, consecutive patients undergoing single-level ALIF with or without subsequent posterior fusion for degenerative lumbar conditions were identified before and after initiation of the MMPC protocol. The MMPC protocol consisted of a preoperative oral regimen of cyclobenzaprine (10 mg), gabapentin (600 mg), acetaminophen (1 g), and methadone (10 mg). Postoperatively they received a bilateral transverse abdominis plane block with 0.5% Ropivacaine prior to extubation. We compared in-hospital opioid consumption between the MMPC and non-MMPC cohorts as well as baseline demographic, the length of hospital stay, cost, and rate of postoperative ileus. Opioid consumption was calculated and normalized to the morphine milligram equivalents (MMEs). RESULTS: In total, 68 patients in the MMPC cohort and 39 in the non-MMPC cohort were identified. There was no difference in baseline demographics including sex, body mass index, smoking status, or preoperative opioid use between the two groups. Although there was no difference in the MMEs on the day of surgery (58.5 vs. 66.9, P=0.387), cumulative MMEs each day after surgery was significantly lower in the MMPC cohort, with final cumulative MMEs being reduced by 62% (120.2 vs. 314.8, P

Background: Cortical bone trajectory (CBT) screws have been recently described as a method of lumbosacral fixation. These screws are typically inserted under fluoroscopic guidance with a medial-to-lateral trajectory in the axial plane and a caudal-to-cephalad trajectory in the sagittal plane. In an effort to reduce surgeon radiation exposure and improve accuracy, CBT screws may be inserted under navigation with intraoperative cone beam computed tomography (CT). However, the accuracy of CBT screw placement under intraoperative navigation has yet to be assessed in the literature. The purpose of the study was to evaluate the accuracy of CBT screw placement using intraoperative cone beam CT navigation. Methods: One hundred and thirty-four consecutive patients who underwent CBT fixation with 618 screws under intraoperative navigation were analyzed from May 2016 through May 2018. Screws were placed by one of three senior spine surgeons using the Medtronic O-Arm Stealth Navigation. Screw position and accuracy were assessed on intraoperative and postoperative CT scans using 2D and 3D reconstructions with VitreaCore software. Results: The majority of surgeries were primary cases (73.1%). The mean age at the time of surgery was 61.5±10.0 years and the majority of patients were female (61.2%). Most patients underwent surgery for a diagnosis of degenerative spondylolisthesis (47.8%) followed by mechanical collapse with foraminal stenosis (22.4%). Ten violations of the vertebral cortex were noted with an average breach distance of 1.0±0.7 mm. Three breaches were lateral (0.5%) and seven were medial (1.1%). The overall navigated screw accuracy rate was 98.3%. The accuracy to within 1 mm of error was 99.2%. There were no intra-operative neurologic, vascular, or visceral complications related to the placement of the CBT screws. Conclusions: CBT screw fixation under an intraoperative cone beam CT navigated insertion technique is safe and reliable. Despite five breaches greater than 1mm, there were no complications related to the placement of the CBT screws in this series.

Background context Patients undergoing single-level posterior lumbar decompression and fusion (PLDF) usually do not need transfusions. However, patients undergoing two or three-level PLDF occasionally require transfusion postoperatively even when estimated blood loss (EBL) or blood loss from drains appears acceptable. Estimating the volume of HBL is critical in perioperative fluid management. Purpose To determine the volume of hidden blood loss (HBL) in 2- or 3- level PLDF. Study Design Single center, multi-surgeon, secondary analysis from a prospective randomized clinical trial of cell-saver use. Patient Sample Patients enrolled in a prospective randomized trial of cell-saver undergoing two- or three-level PLDF were included in this analysis. Methods Total blood loss was calculated using four estimation formulas including Bourke's, Gross’, Camarasa's, and Lopez-Picado's formulas. HBL was determined by subtracting the visible loss (EBL and blood loss from drains) from the calculated total blood loss. Results A total of 89 patients (36 males, mean age 62 years) were included. Seventy-five patients underwent open two-level fusion while 14 had three-level fusions. Intervertebral fusion was performed in 20 patients. Mean surgical time was 261 minutes, and EBL was 685 ml. Mean blood loss from drains was 824 ml. Seventy patients received allogenic blood while 47 Cell Saver blood reinfused intraoperatively. Hidden blood loss was calculated to be 678 ml, 963 ml, 1267 ml, and 819 ml using each formula. Conclusions HBL following two or three-level PLDF was substantial and more than EBL. Postoperative management of blood loss should take HBL into account.

Study Design: Medicare database analysis. Objective: The purpose of this study was to investigate whether neurologic disorders represent a risk factor for revision after lumbar spine surgery. Methods: Patients who underwent lumbar spine surgery were identified from 5% Medicare Part B claims between 2005 and 2008. Cox regression analysis was used to evaluate risk factors for revision within the 7 years after the index lumbar surgery. Covariates included age, gender, race, census region, Medicare buy-in status, Charlson score, year, prior lumbar fusion within 2 years of index surgery, prior diagnosis of cervical spondylotic myelopathy treated with or without cervical spine surgery, and diagnoses of other neuromuscular conditions. Results: Of 8665 cases who had decompression only, 401 (5%) had a revision within 7 years after the index surgery. Factors predictive of revision were prior lumbar fusion (hazard ratio [HR] = 2.78, confidence interval [CI] = 1.43-5.37, P = .002) and being female (HR = 1.61, CI = 1.31-1.97, P < .001). Of 5501 cases who had a decompression and fusion, 752 (14%) had a revision surgery within 7 years after the index surgery. Factors predictive of revision were the presence of a neurologic disorder (HR = 1.24, CI = 1.05-1.46, P = .010), prior lumbar fusion (HR = 3.09, CI = 2.05-4.63, P < .001), and being female (HR = 1.35, CI = 1.15-1.57, P < .001). Conclusions: An increase in revision rate ( P = 0.01, HR = 1.24) was seen in patients with neurologic disorders undergoing lumbar decompression and fusion, although not for patients undergoing decompression alone. This suggests an opportunity to improve clinical outcome and reduce revision rate through improved surgical decision making or treatment of the neurologic disorder.

Study Design Prospective observational cohort. Objectives To examine the cost-effectiveness of IntraOperative ElectroMyeloGraphy (IO-EMG) by evaluating how often an abnormal IO-EMG signal changed the surgeon’s surgical plan, or replaced a pedicle screw either intra-operatively or as a second unplanned surgery. Methods Patients undergoing instrumented posterolateral lumbar fusion were monitored with intraoperative triggered EMG’s. Pedicle screws were placed freehand from L1 to S1 by attending physicians and fellows. Concern for pedicle breach was a screw stimulationResults There were 145 cases with a total of 725 pedicle screws placed. Mean age was 57.8 ± 14.2 yrs, OR time was 238 ± 95 minutes, EBL was 426.8 ± 354.3cc. Mean number of surgical levels fused was 2.7 ± 1.1. 686 (95%) screws stimulated at >10 mA and 39 (5%) screws stimulated at Conclusions Only 1% of the 725 lumbar pedicle screws placed in 8 of 145 cases required repositioning. Due to the infrequency of pedicle wall breaches and the cost of ION, the utility of this modality in straightforward lumbar fusions should be critically evaluated.

Background With the current opioid crisis, as many as 38% of patients are still on opioids one year after elective spine surgery. Identifying drivers of in-hospital opioid consumption may decrease subsequent opioid dependence. We aimed to identify the drivers of in-hospital opioid consumption in patients undergoing 1-2-level instrumented lumbar fusions. Methods This is a retrospective cohort study. Electronic medical record analysts identified consecutive patients undergoing 1-2 level instrumented lumbar fusions for degenerative lumbar conditions from 2016 to 2018 from a single-center hospital administrative database. Oral, intravenous, and transdermal opioid dose administrations were converted to morphine milligram equivalents (MME). Linear regression analysis was used to determine associations between postoperative day (POD) 4 cumulative in-hospital MMEs and the patients' baseline characteristics including body mass index (BMI), race, American Society of Anesthesiologists (ASA) grade, smoking status, marital status, insurance type, zip code, number of fused levels, approach and preoperative opioid use. Results A total of 1,502 patients were included. The mean cumulative MMEs at POD 4 was 251.5. Linear regression analysis yielded four drivers including younger age, preoperative opioid use, current smokers and more levels fused. There were no associations with surgical approach, zip code, ASA grade, marital status, BMI, race or insurance type. Conclusions Use of preoperative opioids and smoking are modifiable risk factors for higher in-hospital opioid consumption and can be targets for intervention prior to surgery in order to decrease in-hospital opioid use.

Study Design: Longitudinal comparative cohort. Objectives: To determine if the duration of symptoms in patients with degenerative spondylolisthesis affects postoperative outcomes after 1- or 2-level decompression and fusion. Methods: Patients undergoing primary surgery for grade 1 degenerative spondylolisthesis at a single Quality Outcomes Database (QOD) participating site were identified. Demographic, surgical and patient-reported outcomes (PROs) data, including baseline and 12-month postoperative Oswestry Disability Index (ODI), back pain (BP, 0-10), leg pain (LP, 0-10), and EuroQOL-5D (EQ-5D) scores were collected. Individual medical records were reviewed for data on duration of symptoms prior to surgery. Patients were stratified into 3 cohorts—those with preoperative symptom duration of less than 1 year, 1 to 2 years, or greater than 2 years. Results: Complete data was available in 123 patients. Significant improvement in ODI, BP, and LP scores were observed in all groups. At 12-month follow-up improvement in ODI, BP, or LP was similar among the cohorts; with a trend toward significance with better improvement in LP scores in patients with a symptom duration of less than 1 year to those with symptom duration greater than 2 years ( P = .058). Conclusions: The duration of symptoms up to 2 years prior to surgery may not be a useful predictor of improvement of back pain or disability scores in patients with spondylolisthesis requiring decompression and fusion. Although there was a positive trend for improvement in leg pain for those with a shorter duration of symptoms, this did not reach statistical significance in our study.

Longitudinal cohort.To investigate whether patients with painful adolescent idiopathic scoliosis experience pain relief with surgical treatment.Adolescent idiopathic scoliosis (AIS) was previously thought to be a painless condition, but recent studies have shown that a significant proportion of patients have pain. Little information is available regarding pain relief with surgical treatment for AIS.Patients enrolled in a prospective database of surgically treated AIS were divided into two groups based on their preoperative Scoliosis Research Society (SRS)-22R pain domain score. Patients with a preoperative pain domain score of 4 or more (N = 1005) were classified as nonpainful. If the preoperative pain domain score was less than 4 (N = 505), they were classified as painful. Demographics, SRS total and domain scores, and changes with treatment were compared for the two groups.The two groups had similar demographics and preoperative coronal curve magnitude. Patients with painful scoliosis experienced significant improvement in SRS-22R pain scores, from 3.29 preoperatively to 4.03 postoperatively (P 0.000). Eighty-one percent of these patients reached the minimum clinically important difference threshold (0.20) for improvement in pain score. Painful scoliosis patients also had greater 2-year improvement in total and all domain scores than the nonpainful scoliosis patients (P 0.000). Absolute values of SRS-22R total and domain scores were all greater at 2 years in the nonpainful group than the painful group.Patients with AIS with substantial back pain can be cautiously counseled to expect significant improvement in pain level with surgical correction of their deformity, even if curve progression is the primary indication for surgery. Although these patients achieve greater improvements in health-related quality of life compared with patients with mild or no pain, 2-year SRS-22R scores were still better in patients with mild or no pain preoperatively.2.

BACKGROUND CONTEXT In patients with lumbar spinal stenosis, it is crucial for clinicians to identify all symptomatic levels. Prior studies have demonstrated that CT-myelography has a greater sensitivity in revealing stenosis (94.4%) compared to MRI (75.9%). CT-myelograms demonstrate weight-bearing changes as opposed to single position and single time point changes on MRI. However, CT-myelography is invasive, requiring injection of contrast dye into the thecal sac. PURPOSE The purpose of this study is to identify patients in whom additional levels of stenosis are likely to be recognized by a CT-myelogram following an MRI scan. STUDY DESIGN/SETTING Retrospective observational cohort at a single multi-surgeon spine center. PATIENT SAMPLE Patients ≥45 years old who had an MRI followed by a CT-myelogram within 6 months with a diagnosis of stenosis, spondylolisthesis, or degenerative scoliosis. OUTCOME MEASURES Additional levels of moderate to severe stenosis identified on CT-myelogram vs MRI. METHODS Medical records were reviewed to collect standard demographic and surgical data and to note if patients were deemed to have single-level or multi-level stenosis clinically. MRIs and CT-Myelograms obtained within six months of each other were reviewed and each lumbar level was recorded as mild, moderate, or severe based on the radiologist's report. Fisher's exact test was performed with change in recorded level of stenosis from MRI to CT-Myelogram as the primary outcome of interest. Results Of 207 patients, 139 (67%) had clinically reported multilevel stenosis and 68 (33%) had single-level stenosis. CT-Myelogram identified a greater proportion of additional stenotic levels in patients with clinically reported multilevel stenosis (80/139, 58%) compared to patients with single-level stenosis (27/68, 40%, p=0.018). When classifying patients based on MRI findings of stenosis instead of clinical diagnosis, 90 (43%) patients had multi-level stenosis, and 117 (56%) had single-level stenosis. In patients with radiologist-reported multilevel stenosis, CT-myelogram also identified a greater proportion of additional stenotic levels (55/90, 61%) compared to patients with radiologist-reported single level stenosis (52/117, 44%, p=0.025). Conclusions CT myelography is significantly more likely to provide valuable additional information in patients with multilevel stenosis as compared to patients with single level stenosis. This finding was consistent regardless of whether the distinction of single-level or multilevel stenosis was determined by clinical diagnosis or based solely off the MRI report. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Recent studies suggest as much as 25% of patients undergoing spine surgery are still on opioids two years later. In response, we developed protocols to minimize opioid consumption following elective spine surgery. Our goal was to evaluate patients undergoing single-level Anterior Lumbar Interbody Fusions (ALIF ± posterior fixation) on MMPC compared to patients who were not (nonMMPC). PURPOSE To determine if the combination of an oral preoperative pain cocktail with transverse abdominis plane (TAP) block (multi-modal pain control: MMPC) will reduce length of stay (LOS), ileus, and in-hospital opioid consumption. STUDY DESIGN/SETTING Retrospective chart review. PATIENT SAMPLE Consecutive patients undergoing single-level ALIF for degenerative lumbar conditions by a single-surgeon. OUTCOME MEASURES Length of stay (LOS), incidence of ileus and in-hospital opioid consumption. METHODS A retrospective review of a prospective, single-surgeon, surgical database was utilized for consistency in technique. Consecutive patients undergoing single-level ALIF for degenerative lumbar conditions were identified before and after initiation of the MMPC. The MMPC consisted of a preop oral regimen of cyclobenzaprine (10mg), gabapentin (600mg), acetaminophen (1g) and methadone (10mg). Postoperatively they received a bilateral transverse abdominis plane (TAP) block with 0.5% Ropivicaine. Our primary outcome was total, in-hospital opioid consumption (morphine milligram equivalents: MME). RESULTS There were 68 patients in the MMPC cohort and 39 in the nonMMPC cohort. There was no difference in baseline demographics such as sex, BMI, smoking, or preoperative opioid use between the two groups. The MMPC cohort was older (56.7 vs 51.1 years, p=0.026). Similar rates of ileus (4 vs 6, p=0.102), no difference in LOS (3.8 vs 4.5, p=0.246) and no difference in index hospital costs was found. Although there was no difference in day of surgery MMEs (58.5 vs 68.9, p=0.387), cumulative MMEs each day after surgery was significantly lower in the MMPC cohort, with final cumulative MMEs being reduced by 62% (120.2 vs 314.8, p CONCLUSIONS The use of a MMPC regimen in patients undergoing single-level ALIF for degenerative conditions reduced opioid consumption starting on POD 1, resulting in a cumulative reduction of 62%. Further research should strive to minimize opioid use and the downstream effects. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Previous studies suggest that a postoperative symptom state with Oswestry Disability Index (ODI)≤20 and pain Numeric Rating Scales (NRS)≤2 following surgery for lumbar degenerative conditions are reasonable thresholds for best outcomes in which patients will be unlikely to seek additional medical care or require additional health-care resources. PURPOSE To identify prognostic factors that predict a “best outcome,” defined as postoperative ODI≤20 and pain NRS≤2 following fusion for lumbar degenerative conditions. STUDY DESIGN Longitudinal observational cohort. PATIENT SAMPLE A total of 396 patients from a single site enrolled in the Quality Outcomes Database who underwent fusion for lumbar degenerative conditions. Outcome Measures Oswestry Disability Index, Back and Leg Pain NRS (0–10). METHODS Collected and analyzed variables included age, sex, body mass index, American Society of Anesthesia grade, number of surgical levels, surgical time, preoperative ODI, preoperative back pain, preoperative leg pain, workmen compensation status, surgical approach, smoking status, and principal diagnosis. RESULTS A total of 74 patients (19%) reported a minimal symptom state at 1-year postoperative (ODI≤20, back pain NRS≤2, and leg pain NRS≤2) and were included in the best outcomes group. Patients in the best outcomes group were older (62 vs. 57 years, p=.001), had lower preoperative ODI (43 vs. 56, p=.000), lower preoperative back pain (6.5 vs. 7.5, p=.000). They had fewer surgical levels (1.25 vs. 1.47, p=.005) and shorter operative times [OR] times (208 vs. 241 minutes, p=.002). They were more likely to have a preoperative diagnosis of spondylolisthesis or disc herniation and less likely to have a diagnosis of adjacent segment disease or mechanical disc collapse (p=.001). Stepwise forward regression analysis revealed diagnosis (p=.023, OR=0.75), age (p=.000, OR=1.04), baseline ODI (p=.000, OR=0.96), and number of levels (p=.019, OR=0.53) as predictive variables. CONCLUSION Achieving a minimal symptom state, defined here as a postoperative ODI≤20 and pain NRS≤2, following fusion for lumbar degenerative conditions is more likely in an older patient with a lower baseline ODI undergoing a single level lumbar fusion for spondylolisthesis.

BACKGROUND CONTEXT Posterior fixation with interbody cage placement can be accomplished via numerous techniques. In attempts to expedite recovery by limiting muscle dissection, the midline interbody fusion (MIDLIF) has been described. More recently, we have developed a robotic-assisted MIDLIF (RA-MIDLIF) technique. Introduction of new technology can potentially be expensive and burdensome. PURPOSE The purpose of this study was to compare index episode of care parameters between patients undergoing either traditional open TLIF (tTLIF), MIDLIF, or RA-MIDLIF. STUDY DESIGN/SETTING Retrospective review of a prospective, multisurgeon, surgical database. PATIENT SAMPLE Consecutive patients undergoing 1- or 2- level RA-MIDLIF, tTLIF or MIDLIF. OUTCOME MEASURES Estimated blood loss (EBL), operative tme (OR Time), length of stay (LOS), total direct hospital cost. METHODS A retrospective review of a prospective, multisurgeon, surgical database was utilized. Consecutive patients undergoing 1- or 2-level RA-MIDLIF for degenerative lumbar conditions were identified and propensity-matched based on age, sex, smoking status, BMI, ASA grade and levels fused to patients undergoing tTLIF or MIDLIF. LOS, EBL, OR Time and direct hospital cost for the index surgical admission were compared. RESULTS Of 55 RA-MIDLIF cases identified, 52 were successfully propensity-matched to patients undergoing tTLIF or MIDLIF. Consistent with propensity matching, there was no difference in age, sex, BMI, ASA grade, smoking status or levels fused. The mean direct hospital cost was similar across all cohorts. Patients undergoing RA-MIDLIF had a shorter average LOS (1.53 days) compared to either MIDLIF (2.71 days) or TLIF (3.58 days). Both MIDLIF and RA-MIDLIFs had lower EBL and less OR time compared to both tTLIF. CONCLUSIONS Despite concerns for additional cost and time while introducing navigation or robotic technology, a propensity-matched comparison of our first 52 robotic-assisted MIDLIF surgeries compared to tTLIF and MIDLIF showed promising results for reducing OR time, EBL, LOS and without increasing cost. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Background Context Transforaminal lumbar interbody fusion (TLIF) and dual-approach anteroposterior (AP) are common techniques to achieve circumferential fusion for lumbar spondylolisthesis. It is unclear which approach is more cost-effective. Purpose Our goal was to determine the incremental cost-effectiveness ratio (ICER) by calculating the cost per quality-adjusted life year (QALY) for each approach. Study Design/Setting This study is a propensity-matched cost-effectiveness comparison. Patient Sample Patients with lumbar spondylolisthesis undergoing single-level AP fusion or TLIF and enrolled in a prospective observational surgical database were included in this study. Outcome Measures The outcome measures in this study were the Oswestry Disability Index (ODI) and the Short Form-6D (SF-6D). Methods From a prospective surgical database, patients with lumbar spondylolisthesis undergoing single-level AP fusion were propensity matched to a TLIF cohort based on age, gender, body mass index, smoking status, workers compensation, preoperative ODI, and back and leg pain numeric scores. Quality-adjusted life years gained were determined using baseline and 1- and 2-yearpostoperative SF-6D scores. Cost was calculated from actual, direct hospital costs and included subsequent postsurgical costs (epidural spinal injections, spine-related emergency department visits, readmissions, and revision surgery). Results Thirty-one cases of AP fusions were identified and propensity matched to 31 TLIF patients. Patients undergoing TLIF had a shorter mean operative time (270 vs. 328 minutes, p=.039) but no difference in estimated blood loss (526 vs. 548 cc, p=.804) or hospital length of stay (4.5 vs. 6.1 days, p=.146). Quality-adjusted life years gained at 2 years were also similar (0.140 vs. 0.130, p=.672). The mean index surgery and the total 2-year costs were lower for TLIF compared with AP (index: $29,428 vs. $31,466; final: $30,684 vs. $331,880). As overall costs were lower and QALYs gained were similar for TLIF compared with AP fusion, TLIF was the dominant intervention with an ICER of $116,327. Conclusions Under our study parameters, surgical treatment of lumbar spondylolisthesis with TLIF is more cost-effective compared with AP fusion. Because of the short-term follow-up, the longevity of this should be further investigated.

STUDY DESIGN: Case-matched retrospective. OBJECTIVES: The purpose of this study is to compare 2-year health-related quality of life (HRQOL) outcomes of patients who underwent 1-level or 2-level posterolateral spine fusion (PSF) versus transforaminal interbody fusion (TLIF) for degenerative spondylolisthesis, disk pathology, and postdecompression instability. SUMMARY OF BACKGROUND DATA: The optimal surgical technique for patients with spondylolisthesis or other degenerative conditions has not been defined. Historically, PSF was the most common procedure, whereas in recent years TLIF has gained popularity. Although theoretical advantages for TLIF have been outlined, evidence for improved outcomes with the addition of interbody support is limited. METHODS: Patients with degenerative spondylolisthesis, with disk pathology and or postdecompression instability who underwent 1-level or 2-level TLIF and completed 2 years postoperative HRQOL measures were identified from a prospective database. These patients were then propensity-matched to a cohort of PSF patients based on age, number of surgical levels, body mass index, sex, smoking status, workers' compensation status, and preoperative outcome measures including the Oswestry Disability Index, SF-36 Physical Component Summary score, SF-36 Mental Composite Summary score, and back and leg pain scores. This produced 63 matched pairs with degenerative spondylolisthesis, 46 with disk pathology and 32 with postdecompression instability. RESULTS: All patients in both groups for each cohort reported statistically significant improvement in HRQOL scores at 2 years postoperatively compared with baseline. Improvements in the Oswestry Disability Index, SF-36 Physical Component Summary score, and back and leg pain scores within the spondylolisthesis and disk pathology subgroups were similar between patients who had a TLIF compared with those who had a PSF. The postdecompression instability subgroup was the only subgroup in which TLIF outperformed PSF for every outcome measure. CONCLUSIONS: Clinical outcome was not significantly altered with TLIF as compared with PSF in patients with spondylolisthesis or disk pathology. However, TLIF resulted in better outcomes at 2 years postoperatively in patients with postdecompression instability.

BACKGROUND CONTEXT Surgeons have used lateral flexion–extension X-ray images to identify patients with clinically substantial instability and listhesis that require fusion. PURPOSE The purpose of this study is to determine the clinical utility of flexion–extension X-ray images by evaluating associations with supine MRI and lateral standing X-ray images and patient reported outcomes (PROs) at baseline and one-year post-op. STUDY DESIGN/SETTING Longitudinal cohort from a multisurgeon, single spine specialty practice. PATIENT SAMPLE Patients enrolled in quality outcome database from a single site with grade 1 spondylolisthesis. OUTCOME MEASURES Back pain (BP), leg pain (LP), and Oswestry Disability Index (ODI). METHODS Patients enrolled in QOD from a single site with grade 1 spondylolisthesis and complete preop and one-year postop PROs, including BP, LP, and ODI, and preop lumbar supine MRIs, lateral standing and flex–ext X-ray images were identified. Slip distance and percentage on all images were measured. Slip difference between flexion and extension was calculated. RESULTS Twenty-seven patients, mean age of 60.5years, 74% female were included. Mean listhesis on flexion films was significantly greater (8.5 mm) than on supine MRI (4.8 mm, p CONCLUSIONS There were no associations between preop or postop PROs and slip severity on any of the imaging modalities. As listhesis on standing and extension films were similar and slip difference between flexion and extension was not associated with PROs, lateral extension films may have limited clinical utility. Further studies are needed to clarify radiographic indications for fusion in patients with spondylolisthesis.

BACKGROUND CONTEXT Provisions in the Patient Protection and Affordable Care Act (PPAC) include alternative payment models that shift away from fee-for-service reimbursement and provide incentives to improve value. These reimbursement models could incorporate the post-discharge facility care and it is therefore important to identify drivers of additional cost, especially in the setting of unexpected non-home discharge. PURPOSE To identify factors associated with being discharged to a non-home location after an elective 1-2 level instrumented lumbar fusion that, if identified, can be useful to allow for early post-discharge planning. STUDY DESIGN/SETTING Retrospective chart review. PATIENT SAMPLE Patients undergoing 1-2 level instrumented lumbar fusions for degenerative lumbar conditions from 2016 to 2018. OUTCOME MEASURES Non-home discharge. METHODS Hospital administrative database and electronic medical record analysts identified consecutive patients undergoing 1-2 level instrumented lumbar fusions for degenerative lumbar conditions from 2016 to 2018. Discharge disposition was determined as home vs non-home (NH). A regression analysis was used to determine associations between NH discharge and an underserved zip code, ASA grade, marital status, race, insurance type, smoking status, BMI, number of levels, approach and revision surgery. RESULTS A total of 1,502 patients (601; 40% male) were included with a mean age of 57.5 years. The majority were discharged home (1,216; 81%). Of the 286 (19%) not discharged home, the majority went to a skilled nursing facility (248). Factors associated with a NH discharge were living in an underserved zip code, not being married, being on government insurance, having more levels fused, higher BMI and older age. Length of stay (5.64 vs 3.03 days, p CONCLUSIONS Patients living in an underserved zip code, not married, higher BMI, older, and having government insurance are more likely to be discharged to a non-home facility after undergoing 1-2 instrumented lumbar fusions. Identification and early intervention to place these patients even before admission may decrease the length of hospital stay and cost. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT In the future, payers may not cover unplanned 90-day emergency room (ER) visits or readmissions after elective lumbar spine surgery. Prior studies using large administrative databases lack granularity, and/or use a proxy for actual cost. We analyzed a large, single-center database to identify risk factors and subsequent costs associated with 90-day ER visits and readmissions. PURPOSE To identify risk factors and subsequent costs associated with 90-day ER visits and readmissions. STUDY DESIGN/SETTING Retrospective longitudinal cohort from a single multisurgeon, spine specialty site PATIENT SAMPLE Patients undergoing elective lumbar spine surgeries from 2013-2017. OUTCOME MEASURES Ninety-day ER visits and readmissions. METHODS A prospective, multisurgeon, single-center database merged with hospital administrative data was queried for elective lumbar spine surgeries from 2013-2017. Predictive models were created for 90-day ER visits and readmissions. RESULTS Of 5,444 patients, 729 (13%) returned to the ER, most often for pain (144, 32%). Predictors of an ER visit were prior ER visit (pER, OR:2.4), zip code (OR:1.4) and number of chronic medical conditions (OR:1.4). 421 (8%) patients were readmitted, most frequently for wound infection (123, 2%), COPD exacerbation (24, 0.4%), and sepsis (23, 0.4%). Predictors for readmission were pER (OR:1.96), multiple chronic conditions (OR:1.69), obesity (non-obese, OR:0.49), race (African American, OR:1.43), admission status (ER admission, OR:2.29) and elevated HbA1c (OR:1.80). Average direct hospital cost for an ER visit was $1,659 and readmission was $7,322, costing the institution $5.1 million over the five-year study period. CONCLUSIONS Risk factors for 90-day ER visit and readmission after elective lumbar spine surgery include medical comorbidities and socioeconomic factors. Proper patient selection, appropriate postop pain management and optimization of modifiable risk factors prior to surgery can lower the 90-day ER visits and readmissions and reduce health care costs. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Our previous study showed that prescribing patterns, more than surgery invasiveness or patient factors, affect post-operative opioid consumption. Since then we have instituted a Standard Escalation Pain Protocol (SEPP): patients receive 0-60 Morphine Milligram Equivalents (MME) above their baseline pre-op MME after surgery. PURPOSE The purpose of this study is to evaluate how prescribing patterns affect immediate postoperative opioid consumption in patients undergoing 1- to 2-level posterior lumbar interbody fusion with a navigated or robotic-assisted, midline exposure (MIDLIF). STUDY DESIGN/SETTING Single surgeon consecutive series. PATIENT SAMPLE Patients with degenerative lumbar pathology who had a MIDLIF from 2017 to 2018 were identified. OUTCOME MEASURES In-hospital opioid consumption. METHODS Patients with degenerative lumbar pathology who had a MIDLIF from 2017 to 2018 were identified and divided into two cohorts: patients who had surgery before the institution of SEPP (PreSEPP) and those who had surgery after (PostSEPP). Length of stay and daily opioid consumption were extracted by EMR data analysts unaware of the purpose of the study. RESULTS The PreSEPP (N=34) and PostSEPP (N=27) patients were similar at baseline in age, sex distribution, ASA grade, BMI and smoking status. Pre-Op (2.2 vs 3.6, p=0.630) and Post-op Day-0 (POD-0, 52.5 vs 38.8, p=0.192) MME consumption was similar between the two groups. At POD-1, cumulative MME consumption was higher in the Pre-SEPP (131.7) compared to the PostSEPP group (76.0, p=0.004) and this was maintained up to discharge (54% total MME reduction). Length of stay was also longer in the PreSEPP (1.97 days) compared to the PostSEPP group (1.37 days, p=0.004). CONCLUSIONS The use of a standard escalation pain protocol decreases in-hospital opioid consumption by 54% and shortens length of stay after 1-2 level lumbar spinal fusion. Similar to our previous study, prescribing pattern is an important factor affecting post-op opioid consumption. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Study design: Retrospective review. Objective: To identify risk factors for cell saver transfusion in lumbar spinal surgery and determine if cell saver transfusions affected intraoperative or postoperative transfusion rates. Summary of background data: Cell saver has been used to minimize allogeneic blood transfusion in lumbar spinal surgery. Conflicting reports exist, which call into question the efficacy of cell saver use. Methods: We reviewed medical records of randomly selected patients who underwent posterolateral fusion with or without transforaminal interbody fusion from July 2010 to June 2011. Transfusion rates and transfusion-related complications were determined. Binary logistic regression was performed to identify risk factors for use of autologous cell saver transfusion. Results: There were 178 females and 107 males, with a mean age of 57.2 years. Of the 285 cases, 39 had no cell saver available, 147 had cell saver available but no autologous blood was recovered or transfused and 99 had an autologous cell saver transfusion. Patients who had cell saver transfusion had a higher rate of intraoperative allogeneic blood transfusion (52%) compared with those who did not (22%). There was no significant difference in the rate of postoperative transfusions or transfusion-related reactions between patients who did and did not have cell saver transfusion. Patient's age, smoking status, American Society of Anesthesiologists grade, use of anticoagulants preoperatively, primary or revision surgery, iliac crest bone graft harvest, anesthesiologist, or surgeon had no significant effect on cell saver infusion. Body mass index (odds ratio [OR] = 1.06), number of posterolateral fusion levels fused (OR = 2.50), and number of transforaminal interbody fusions performed (OR = 2.41) were independent risk factors for the use of autologous cell saver transfusion. Conclusion: Body mass index, multi-level fusion and transforaminal interbody fusion result in increased use of autologous cell saver transfusion in lumbar spinal surgery. Use of autologous cell saver transfusion did not reduce the requirement for intraoperative or postoperative allogeneic blood transfusion. Level of evidence: 2.

Background context Acinic cell carcinoma is the fourth most common tumor of the parotid gland, and spinal metastases are thought to be exceedingly rare. Only two other reported presentations are found in the literature, both presumably secondary to incomplete surgical resections. Purpose To present the first known case of metastasis to the lumbar spine causing vertebral body involvement, after complete resection of the parotid gland. Study design Case report. Methods A case of a patient who presented with low back pain and had imaging studies showing an expansive destructive lesion of the L4 vertebral body. The patient underwent a radical parotidectomy and radiation therapy for dedifferentiated, high-grade acinic cell carcinoma 2 years prior. Results The patient underwent anterior L4 corpectomy and strut cage placement and posterior pedicle screw fixation from L2 to L5 on the same day, followed by radiation and oral chemotherapy 3 weeks later. Histopathologic examination confirmed metastatic dedifferentiated acinic cell carcinoma, present in the L4 vertebral body and overlying psoas muscle. Conclusions This case report underscores the importance of careful evaluation of patients presenting with back pain with a history of malignancy. It also calls into question the traditional low-grade classification ascribed to these tumors, given their ability to metastasize after complete excision and adjuvant therapy.

BACKGROUND CONTEXT In 2016 alone, 19,413 deaths were attributed to prescription opioid overdoses. Understanding the drivers of opiate consumption in postoperative lumbar spinal fusion patients is a high priority. PURPOSE To determine if surgical invasiveness and/or preoperative opiate use influences immediate postoperative opiate consumption. STUDY DESIGN/SETTING Propensity matched longitudinal cohort. PATIENT SAMPLE Patients from a multi-surgeon, single spine specialty center with degenerative lumbar pathology who underwent an instrumented posterior lumbar decompression and interbody fusion (MIDLIF or TLIF). OUTCOME MEASURES Oswestry Disability Index, morphine equivalent doses (MED) from postoperative day (POD) #0 through POD #4. METHODS A single-center, multi-surgeon, retrospective review identified patients with degenerative lumbar pathology who underwent an instrumented posterior lumbar decompression and interbody fusion (MIDLIF or TLIF). Patients in each cohort were propensity-matched based on age, sex, smoking status, BMI, diagnosis, ASA grade and levels fused. MED POD #0 through POD #4 were calculated. Preoperative opiate prescriptions were recorded to determine baseline opioid use. RESULTS Of 214 MIDLIF and 281 TLIF patients undergoing surgery, 33 patients in each cohort were successfully propensity matched with no differences in baseline characteristics. There was no difference in immediate postoperative mean total MED between the cohorts (MIDLIF=370, TLIF=302, p=.398). Forty-three (65%) of patients were taking opiates prior to surgery. Opiate-naive patients required less narcotics (MED=248) compared to nonopiate naive patients (MED=383, p=.071) but this was not significant. Patients taking opiates preop had worse baseline ODI (56.5 vs. 47.2, p=.023) and 1-year postop ODI (46.3 vs. 30.9, p=.015). CONCLUSIONS Neither surgical invasiveness nor preoperative opiate use have an impact on immediate postop opiate consumption. This is likely secondary to non-individualized prescribing patterns. Patients taking preop narcotics have worse baseline, 1-year, and improvement in ODI following 1- and 2-level MIDLIFs or TLIFs. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Posterior instrumented lumbar fusions are commonly performed utilizing interbody fusions. Recently, a minimally invasive technique of midline exposure with cortical bone trajectory screw fixation has been described (MIDLIF). The goal is to limit muscle dissection, decreasing surgical morbidity and expedite recovery. PURPOSE The purpose of this study was to compare index episode of care (iEOC) cost between patients undergoing MIDLIF versus tTLIF. STUDY DESIGN/SETTING Multi-surgeon single-center spine specialty tertiary practice. PATIENT SAMPLE Consecutive patients undergoing 1- or 2-level MIDLIF or tTLIF for degenerative lumbar conditions were identified. OUTCOME MEASURES Index episode of care cost data for surgical and hospital stay parameters and included actual, direct, hospital cost. METHODS A retrospective review of a prospective, multi-surgeon, surgical database was utilized. Consecutive patients undergoing 1- or 2-level MIDLIF or tTLIF for degenerative lumbar conditions were identified. Patients in each cohort were propensity-matched based on age, sex, smoking status, BMI, diagnosis, ASA grade and levels fused. iEOC cost data was collected for surgical and hospital stay parameters and included actual, direct, hospital cost for the index surgical visit. RESULTS Of 214 and 281 patients undergoing MIDLIF or tTLIF, respectively, 105 cases in each cohort were successfully propensity-matched. Consistent with propensity matching, there was no difference in age, sex, BMI, diagnosis, ASA score, smoking status, or levels fused. Spondylolisthesis was the most common indication for surgery in both cohorts. The mean total iEOC was $706 ($16,604 vs. $17,310) lower for MIDLIF versus tTLIF. There was no difference in implant (p=.193) or biologic (p=.145) cost but blood utilization (p=.000), OR supplies (p=.000), hospital room/board (p=.000), pharmacy (p=.010), and therapy (p=.009) costs were all significantly lower in MIDLIF. Additionally, mean LOS was decreased for MIDLIF (2.97 vs. 4.02, p=.000). CONCLUSIONS Compared to traditional open tTLIF, patients undergoing MIDLIF have several cost parameters of the iEOC that are significantly lower as well as a shorter length of stay. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Study design Randomized clinical trial. Objective To perform a cost-utility analysis using actual cost data from a randomized clinical trial of patients over 60 years old who underwent posterolateral fusion using either rhBMP-2/ACS or iliac crest bone graft (ICBG). Summary background data Bone morphogenetic protein has been shown to be an effective bone graft substitute for spine fusion. However, a clinical trial-based economic analysis of rhBMP-2/ACS compared with iliac crest bone graft has not been done. Methods Patients over 60 years old requiring decompression and posterolateral fusion were randomized to rhBMP-2/ACS (n = 50) or ICBG (n = 52). A dedicated hospital coder and research nurse tracked each patient to determine direct costs of inpatient care and all postoperative healthcare encounters up to 2 years after surgery. Preoperative and 2-year-postoperative SF-6D utility scores for each patient were determined. A decision tree was created, which included the probability of complications, need for additional treatments and revision surgery; and the costs associated with initial surgery and treatment for complications and additional treatment for continued spine symptoms; and utility scores. Results The mean total 2-year cost for care (excluding complication and additional spine treatment costs) was $34,235 in the ICBG group and $36,530 in the rhBMP-2/ACS group. For the entire group, the mean cost to treat a major complication was $10,888, the cost of revision surgery for nonunion was $46,852, and additional treatment for spine-related events was $5892. In the ICBG group, 8 patients had complications; 20 had additional interventions, 5 of whom required revision for nonunion. In the rhBMP-2/ACS group, 6 patients had complications, 10 had additional interventions, and 1 required revision for nonunion. The cost of using rhBMP-2/ACS was $39,967 with a 0.11 mean improvement in SF-6D; and for ICBG the cost was $42,286 with a mean improvement of 0.10 in SF-6D. Conclusion There are more complications, increased need for additional treatment and revision surgery in patients over 60 years old receiving ICBG compared with rhBMP-2/ACS. This may account for higher costs and lower improvements in utility seen in patients receiving ICBG compared with rhBMP-2/ACS in this study population.

Background One of the primary difficulties in evaluating the effectiveness of lumbar fusion is that, with the exception of spondylolisthesis, specific diagnostic indications for surgery are poorly defined. Diagnostic specificity beyond the symptom of low back pain or the presence of lumbar degeneration needs to be delineated such that outcomes data can be effectively translated into clinical decision making or evidence-based guidelines. Purpose The purpose of this study was to report on prospectively collected clinical outcome measures, stratified by diagnosis, among a series of patients with lumbar degenerative disease whose treatment included lumbar spine fusion. Study design Demographics, diagnostic categorization, and clinical outcome measures were prospectively collected by six spine surgeons at a single tertiary spine center, as part of the surgeons' standard clinical practice. Patient sample Four hundred and twenty-eight patients were enrolled in the study and complete 1- and 2-year Health-Related Quality of Life (HRQOL) data were available in 327 patients whose treatment included decompression and posterolateral lumbar fusion. Outcome measures The Oswestry Disability Index (ODI), Short Form-36 (SF-36), numeric rating scales for back pain and leg pain. Methods Preoperative diagnosis was classified, in the primary surgical cases, as disc pathology, spondylolisthesis, instability, stenosis, or scoliosis. In revision cases, the diagnosis was classified as nonunion, adjacent level degeneration, or postdiscectomy revision. Patient-reported outcomes at 1 and 2 years post-op were assessed based on diagnostic stratification. Statistical evaluation of clinical outcome was performed for both mean net change in outcome scores and the percentage of patients reaching a minimum clinically important difference (MCID) threshold for each outcome measure. Results Preoperative diagnosis was spondylolisthesis (n=80), scoliosis (n=17), disc pathology (n=33), instability (n=21), stenosis (n=46), postdiscectomy revision (n=67), adjacent level degeneration (n=40), or nonunion (n=23). Evaluation of 2-year post-op HRQOL measures by diagnostic subgroup revealed the most substantial improvement in ODI score for patients with spondylolisthesis (22.7 points) and scoliosis (21.2 points). Patients with the diagnosis of disc pathology (16.2 points), postdiscectomy revision (14.0 points), instability (12.7 points), stenosis (10.6 points), and adjacent level degeneration (9.5 points) demonstrated a progressively smaller magnitude of ODI improvement. The least ODI improvement at 2 years after surgery was seen in patients with nonunion of a prior fusion (5.5 points). The percentage of patients reaching MCID for ODI at 2 years post-op ranged from 71.0% in the spondylolisthesis subgroup to 34.8% in the nonunion subgroup. The greatest SF-36 physical component score improvement at 2-year follow-up was seen in patients with disc pathology (7.9 points) and spondylolisthesis (7.7 points), followed by scoliosis (6.6 points) and stenosis (6.5 points), instability (5.6 points), postdiscectomy revision (5.3 points) nonunion (3.1 points) and adjacent level degeneration (2.5 points). No significant changes from Year 1 to Year 2 were noted in any of the subgroups. For SF-36 physical component score, percentage of patients reaching MCID ranged from 63.6% in the disc pathology subgroup to 25% in the nonunion subgroup. Conclusions This study supports the concept that added diagnostic specificity is a critical component in building an improved evidence base for lumbar fusion surgery. The magnitude of HRQOL improvement was not equal among diagnostic subgroups. The percentage of patients reaching an MCID level of improvement was also significantly influenced by diagnostic stratification. Without diagnostic specificity for entities beyond spondylolisthesis, the absence of well-defined study populations will continue to limit our ability to move toward evidence-based decision making.

Sagittal imbalance is a significant factor in determining clinical treatment outcomes in patients with deformity. Measurement of sagittal alignment using the traditional Cobb technique is frequently hampered by difficulty in visualizing landmarks. This report compares traditional manual measurement techniques to a computer-assisted sagittal plane measurement program which uses a radius arc methodology. The intra and inter-observer reliability of the computer program has been shown to be 0.92–0.99. Twenty-nine lateral 90 cm radiographs were measured by a computer program for an array of sagittal plane measurements. Ten experienced orthopedic spine surgeons manually measured the same parameters twice, at least 48 h apart, using a digital caliper and a standardized radiographic manual. Intraclass correlations were used to determine intra- and interobserver reliability between different manual measures and between manual measures and computer assisted-measures. The inter-observer reliability between manual measures was poor, ranging from −0.02 to 0.64 for the different sagittal measures. The intra-observer reliability in manual measures was better ranging from 0.40 to 0.93. Comparing manual to computer-assisted measures, the ICC ranged from 0.07 to 0.75. Surgeons agreed more often with each other than with the machine when measuring the lumbar curve, the thoracic curve, and the spino-sacral angle. The reliability of the computer program is significantly higher for all measures except for lumbar lordosis. A computer-assisted program produces a reliable measurement of the sagittal profile of the spine by eliminating the need for distinctly visible endplates. The use of a radial arc methodology allows for infinite data points to be used along the spine to determine sagittal measurements. The integration of this technique with digital radiography’s ability to adjust image contrast and brightness will enable the superior identification of key anatomical parameters normally not available for measurement on traditional radiographs, improving the consistency of sagittal measurement.

STUDY DESIGN Retrospective cohort analysis. OBJECTIVE To investigate and compare back and leg pain, and health-related quality of life measures in obese patients undergoing lumbar spine fusion, and to compare the results to nonobese patients. SUMMARY OF BACKGROUND DATA Obesity is a growing healthcare crisis in the United States and an increasing number of patients undergoing spinal surgery are obese. Obesity is also associated with low back pain. Some obese patients with significant structural spine problems may be dismissed as having their pain only coming from their weight. We compared patient outcomes in obese and nonobese patients undergoing lumbar fusion surgery. METHODS We retrospectively reviewed a single-center patient database of patients undergoing lumbar fusion and identified 270 patients with greater than 2-year outcome data. Body mass index (BMI) was calculated and patients were classified as obese (BMI >or= 30) or nonobese (BMI < 30). All patients completed Oswestry Disability Index (ODI), Short Form (SF)-36 questionnaires, and back and leg pain numerical rating scores before surgery and at 2 years. We compared clinical outcomes and complication rates in the 2 groups. RESULTS The overall study group consisted of 109 obese patients and 161 nonobese patients. Both the obese and nonobese patients demonstrated significant improvements in back pain, leg pain, SF-36 physical composite summary (PCS), and ODI scores (P < 0.001) at 2-year follow-up compared with baseline. There was no significant difference in the mean improvements seen in obese patients compared with nonobese patients with respect to back pain, leg pain, or SF-36 PCS or ODI scores. Both SF-36 PCS (P = 0.037) and ODI score (P = 0.028) at 2-year follow-up were better in the nonobese patients compared with the obese patients. Overall complication rates were slightly higher in the obese group (P = 0.045), predominantly because of wound-related complications. CONCLUSION Obese patients undergoing lumbar fusion achieve similar benefits to nonobese patients. Wound-related complications are more common in obese patients. Obese patients with otherwise good indications for lumbar fusion should not be denied this procedure because of their weight.

Background context There is mounting evidence supporting the efficacy of bone morphogenetic protein (BMP) for both anterior interbody and posterolateral lumbar fusion. However, the relative cost of BMP remains an important concern for physicians, hospitals, and payers. Purpose The purpose of this study is to report on the perioperative costs for patients treated with rhBMP-2 as compared with an iliac crest bone graft (ICBG) supplemented with graft extenders. Study design/setting A prospective randomized controlled trial of rhBMP-2/ACS (Infuse Bone Graft; Medtronic Sofamor Danek, Memphis, TN) versus ICBG±graft extender for lumbar spine fusion in patients over 60 years old. Patient sample One hundred two patients over 60 years old who required a posterolateral lumbar spine fusion randomized between receiving rhBMP-2/ACS or ICBG. Outcome measures All health-care costs over the first 3 months after surgery. Methods As part of a prospective randomized trial of rhBMP-2/ACS versus ICBG±graft extender for lumbar spine fusion, all costs over the first 3 months after surgery were directly recorded by a dedicated coder funded by Norton Healthcare, Louisville, KY. A dedicated research nurse also followed all patients throughout their hospital stay and posthospitalization recovery to identify any adverse events or additional outpatient medical care. Results Fifty patients received rhBMP-2/ACS and 52 underwent ICBG harvest. The mean hospital cost for the index admission was $24,736 for the rhBMP-2/ACS group and $21,138 for the ICBG group. Mean inpatient physician costs were $5,082 in the rhBMP-2/ACS group and $5,316 in the ICBG group. Costs associated with posthospital rehabilitation averaged $4,906 in the rhBMP-2/ACS group versus $6,820 in the ICBG group. Total payer expenditure for the 3-month perioperative period averaged $33,860 in the rhBMP-2/ACS group and $37,227 in the ICBG group. Conclusions The hospital carries the cost burden associated with the utilization of rhBMP-2/ACS. In contrast, the payer in a Diagnosis-Related Group (DRG) model achieves a net savings, based primarily on the decreased payment for inpatient rehabilitation, but also on decreased hospital reimbursement, physician costs, and other outpatient services.

Although outcomes after cervical fusion in rheumatoid arthritis (RA) patients are widely published, outcomes of lumbar fusion in RA patients has not been reported. Nineteen patients with RA, identified using ICD-9 and CPT codes, who underwent instrumented posterolateral lumbar fusion were matched for age, gender, smoking status, date, and level of surgery to a contemporaneous non-RA group. Medical records and radiographs were reviewed by the primary author who had no role in the treatment of these patients. The average age was 64 years in the RA group and 65 years in the non-RA group. The male to female ratio was 2:17 and 1:18, respectively. There were three smokers and two diabetics in each group. An average of 1.5 levels was fused in each group. Average follow-up was 24 and 27 months, respectively. In the RA group, 15 patients were taking DMARDs with 7 of those also taking oral steroids; 4 patients were taking NSAIDs only. There were seven complications (37%) in the RA group versus four (21%) in the non-RA group; wound infections in three patients (16%) in the RA group versus one (5%) in the non-RA group; and non-union in two patients (11%) in the RA group versus three (16%) in the non-RA group. Clinical outcomes were similar between the two groups with 74% of patients achieving good to excellent results in the RA group compared to 63% in the non-RA group (p = 0.692). Surgeons and their RA patients who undergo an instrumented lumbar fusion can expect a slightly higher complication rate than patients without RA which may be related to osteopenia and immunosuppression.

Background Context Obesity is a growing problem in health care. Studies have demonstrated similar functional outcomes but higher complication rates after spine surgery in obese patients. Purpose This study aimed to compare patient-reported outcomes and revision rates 5 years after instrumented posterior lumbar fusion between normal, overweight, and obese patients. Study design Propensity matched case control. Patient sample Patients who had posterior instrumented lumbar spinal fusion from 2001 to 2008 from a single spine specialty center with complete preoperative and 5-year postoperative outcome measures were identified. Outcome measures Oswestry Disability Index (ODI), Back Pain (0–10) and Leg Pain (0–10) Numeric Rating Scales, and Short Form-36 Physical Composite Summary Scores (SF-36 PCS). Methods Three comparison groups, one with body mass index (BMI) ≥20–25 kg/m 2 (normal), another with ≥25– 2 (overweight), and another with ≥30–40 kg/m 2 (obese) were created using propensity matching techniques based on demographics, baseline clinical outcome measures, and surgical characteristics. Five-year postoperative outcome measures and revision rates in the three groups were compared. One-way analysis of variance was used to compare continuous variables, and Fisher exact test was used to compare categorical variables between the groups. Significance was set at p Results There were 82 cases matched in each cohort. Estimated blood loss (440 cc vs. 702 cc vs. 798 cc, p=.000) and operative time (234 minutes vs. 263 minutes vs. 275 minutes, p=.003) were significantly greater in the overweight and obese patients. Improvements in ODI (14.2 vs. 9.6 vs. 10.4, p=.226), SF-36 PCS (5.9 vs. 2.9 vs. 3.5, p=.361), back pain (3.0 vs. 2.0 vs. 2.1, p=.028), and leg pain (3.0 vs. 2.3 vs. 2.3, p=.311) scores were similar among the groups. Revision rates (14 vs. 15 vs. 13, p=.917), and time between index and revision surgery (p=.990) were similar among the three groups as well. Conclusion When considering a subset of patient-reported outcomes and revision surgery after 5 years, patients with an elevated BMI >25 at baseline did not appear to have worse outcomes than those with a normal BMI of 20–25 when undergoing posterior lumbar fusion surgery. Obesity should not be considered a contraindication to surgery in patients with appropriate surgical indications.

This is a prospective study of 26 patients undergoing posterior cervical spine instrumentation with lateral mass or pedicle screws to determine the correlation between intraoperative screw stimulation thresholds and the position of posterior cervical lateral mass and pedicle screws.One hundred forty-seven posterior cervical screws (122 lateral mass screws and 25 C7 pedicle screws) in 26 patients were electrically stimulated intraoperatively and stimulation thresholds recorded. Computed tomography (CT) scans were taken postoperatively and were evaluated independently to assess screw position. Electromyographic (EMG) thresholds and CT data were compared to assess the accuracy of the EMG screw stimulation technique in detecting screw malposition.Intraoperative electrical stimulation was accurate in verifying screw position. A stimulation threshold of 15 mA provided a 99% positive predictive value (89% sensitivity, 87% specificity) that the screw was within the lateral mass or pedicle. Stimulation values of 10-15 mA provided a 13% predictive value (66% sensitivity, 90% specificity) that the screw was within the lateral mass or pedicle. A stimulation value of10 mA provided a 100% predictive value that the screw was malpositioned (70% sensitivity, 100% specificity).Intraoperative evoked EMG monitoring is a valuable tool in posterior cervical instrumentation using lateral mass and pedicle screws. Stimulation thresholds in this study correlated with screw position. Stimulation values of15 mA reliably predict acceptable screw position. Values between 10 and 15 mA are generally associated with acceptable screw position, although exploration is recommended. Values below 10 mA are associated with screw malposition and warrant exploration, repositioning, and possible removal.

Posterior spinal arthrodesis is commonly employed in patients with spinal stenosis, although certain patients may require additional interbody support applied either anteriorly or posteriorly. Although autograft, allograft, and recent biologic agents such as rhBMP-2 are available for arthrodesis, meticulous fusion technique is still essential for a successful result. Posterior pedicular screw and rod fixation remain the most commonly employed internal fixation for the treatment of spinal stenosis since it allows for stabilization of instability, correction of deformity, and improved arthrodesis success. This article outlines the etiology, pathogenesis, current treatment options, and various surgical techniques available for the treatment of spinal stenosis.

Spondylolisthesis is defined as the forward translation of one vertebra on another in the sagittal plane. There are multiple etiologies of spondylolisthesis, including the degenerative and postsurgical varieties. Degenerative spondylolisthesis presents in a more elderly population and usually involves the lumbar fourth and fifth vertebrae. The pathogenesis is believed to be secondary to the progressive degeneration of the disc and facets, which results in instability and pathologic segmental motion. Clinically, patients present with low back pain and neurological symptoms consisting of spinal claudication or radiculopathy. A postsurgical spondylolisthesis is often the inevitable result of decompression with up to 50% of patients developing late instability that requires stabilization. Similar to a degenerative spondylolisthesis, these patients will present with reoccurrence of radicular pain associated with increasing low back pain. A spondylolisthesis is identified with plain radiographs, which should include flexion and extension to identify pathologic motion. An MRI is useful for the evaluation of stenosis, while a Myelo/CT with flexion and extension weight-bearing views is superior for the evaluation of dynamic instability. Nonoperative treatment consists of bracing, nonsteroidal antiinflammatory medication, epidural blocks, weight reduction, and physical therapy. Surgical indications include severe back pain or neurological symptoms. Following decompression, an arthrodesis is recommended for a degenerative spondylolisthesis since long-term studies have demonstrated improved outcomes. A postsurgical spondylolisthesis, by definition, is unstable and requires a concurrent stabilization. Surgical options include posterior pedicular rod and screw fixation, posteriorly placed interbody implants combined with pedicular instrumentation, or combined anterior and posterior procedures. Materials available for fusion include autograft, allograft, or new biologic graft substitutes such as rhBMP-2. This article reviews the etiology and pathogenesis of spondylolisthesis along with recommended treatment options and surgical techniques to enable clinicians to insure superior patient treatment outcomes.

STUDY DESIGN This report describes a case of vertebral body osteonecrosis associated with the use of intradiscal electrothermal therapy. OBJECTIVES To alert clinicians to a previously unreported complication, vertebral body osteonecrosis, after an intradiscal electrothermal therapy procedure. SUMMARY OF BACKGROUND DATA The intradiscal electrothermal therapy procedure is a new treatment that has been advocated in the management of chronic low back pain of discogenic origin. The intradiscal electrothermal therapy procedure uses a fluoroscopically guided thermal catheter to heat the intervertebral disc. A review of the literature regarding this procedure has not revealed osteonecrosis as a complication. METHODS The patient's work-up and postoperative course are documented, and all medical records were reviewed retrospectively. RESULTS The patient's pain had improved only minimally at initial follow-up after L5-S1 combined anterior and posterior spinal fusion, undertaken after intradiscal electrothermal therapy failure. CONCLUSIONS Intradiscal electrothermal therapy has gained increasing popularity in the treatment of discogenic low back pain, in large part because of its minimally invasive nature and perceived low risk for major complications. Previous reports in the literature have not noted any major complications associated with the proper use of this device. Clinicians should be advised that intradiscal electrothermal therapy can be associated with complications, which in the current case, led to osteonecrosis of the vertebral body.

Background: Revision rotator cuff repair is a surgical challenge, and the results have generally been inferior to those of primary repair. We examined the results of revision rotator cuff repair in a large series of patients and assessed which subgroups of patients had the greatest chance for a satisfactory functional outcome. Methods: A revision rotator cuff repair was performed in eighty patients after the failure of a previous operative repair. The average age of the patients at the time of the revision was fifty-nine years. Prior to revision, the average pain score was 7.4 points (with 0 points indicating no pain and 10 points, severe pain) and the active range of motion of the shoulder averaged 105° of elevation, 39° of external rotation, and internal rotation to the eleventh thoracic vertebra. All patients underwent repeat repair of the rotator cuff tendons to bone. Additional procedures included revision acromioplasty (fifty-three patients; 66%) and distal clavicular excision (twenty-six patients; 33%), among others. Results: After an average duration of follow-up of forty-nine months, the result was rated as satisfactory (excellent, good, or fair) in fifty-five patients (69%) and as unsatisfactory (poor) in twenty-five (31%). At the time of the latest follow-up, the average pain score had improved to 3.0 points and the active range of motion averaged 130° of elevation, 53° of external rotation, and internal rotation to the tenth thoracic vertebra. Improved results were associated with an intact deltoid origin, good-quality rotator cuff tissue, preoperative active elevation of the arm above the horizontal, and only one prior procedure. All seventeen patients who met all four of these criteria had a satisfactory result. Conclusions: The results of revision rotator cuff repair are inferior to those of primary repair. While pain relief can be reliably achieved in most patients, the functional results are improved principally in patients with an intact deltoid origin, good-quality rotator cuff tissue, preoperative elevation above the horizontal, and only one prior procedure.

Aggrecan is the major proteoglycan of the meniscus, and its primary function is to give the meniscus its viscoelastic compressive properties. The objective of this study was to determine the effect of joint immobilization on aggrecan gene expression in the meniscus. The right hindlimbs of six mature beagles were knee cast-immobilized in 90° of flexion and supported by a sling to prevent weightbearing, while the contralateral limb was left free to bear weight. The animals were sacrificed at 4 weeks, and the anterior and posterior halves of the medial and lateral menisci were analyzed separately. Analysis of aggrecan gene expression by quantitative polymerase chain reaction showed decreased aggrecan gene expression in menisci from immobilized knees (P 0.01, two-way analysis of variance). Aggrecan gene expression decreased by a factor of 2 to 5.5 in the different regions examined. Analysis of the composition of the meniscus also showed decreased proteoglycan content and increased water content with immobilization (P 0.05, two-way analysis of variance). These results show that joint immobilization can significantly affect meniscal cellular activity and composition and can therefore potentially affect meniscal function.

Thirty patients (31 shoulders) were retrospectively reviewed after hemiarthroplasty for glenohumeral osteoarthritis. Ten shoulders had primary osteoarthritis, and 21 shoulders had secondary osteoarthritis. Glenoid surface wear was evaluated and classified as either type I, concentric, (15 shoulders) or type II, nonconcentric, (16 shoulders). Postoperative results were reviewed with the American Shoulder and Elbow Surgeons' evaluation form, Neer classification, and the Constant score. Overall, 23 (74%) shoulders achieved satisfactory results, and 8 (26%) shoulders had unsatisfactory results. Results were similar in the primary and secondary osteoarthritis groups. Outcome correlated most significantly with the status of posterior glenoid wear. Patients with concentric, type I glenoids achieved 86% satisfactory results, whereas patients with nonconcentric, type II glenoids had only 63% satisfactory results. Although pain relief was similar in both groups, the unsatisfactory results were attributed to loss of forward elevation and external rotation in patients with type II glenoids. On the basis of these results hemiarthroplasty can be an effective treatment for both primary and secondary arthritis but should be reserved for patients with a concentric glenoid, which affords a better fulcrum for glenohumeral motion. (J Shoulder Elbow Surg 1997;6:449-54.)

Tendons are complex composite material composed primarily of water, collagen, proteolycans, and cells, designed to transmit tensile loads from muscle to bone. Although rotator cuff tendons differ in many ways from other tendons in the body, a knowledge of basic tendon structure and function is helpful in understanding rotator cuff tendon biology, injury, and repair. In addition to type I collagen, rotator cuff tendons contain small amounts of type III collagen, which play a role in healing and repair. In comparison with other tendons, the increased glycosaminoglycan and proteoglycan content seen in rotator cuff tendons may be adaptive, pathologic, or both. The etiology of rotator cuff pathology is probably related to trauma, aging, and degeneration. As our understanding of these processes increases, we will be able to develop and implement improved preventative and therapeutic interventions for rotator cuff pathology.

Study design Retrospective review. Objective To determine the incremental cost-effectiveness of cell saver for single-level posterior lumbar decompression and fusion (PLDF). Summary of background data Intraoperative cell salvage is used during surgery to reduce the need for perioperative allogeneic blood transfusion. Although the use of cell saver may be beneficial in certain circumstances, its utility has not been clearly established for the common procedure of an adult single-level PLDF. Methods Randomly selected adult patients treated with a single-level PLDF between July 2010 and June 2011 at a single institution were identified. Patients who had a combined anterior and posterior approach were excluded. The final study sample for analysis consisted of 180 patients. Hospital records were reviewed to determine whether: (1) cell saver was available during surgery, (2) recovered autologous blood was infused, and (3) the patient received intra- or postoperative allogeneic transfusions. Estimated blood loss, levels fused, volume(s) transfused, and all related complications were recorded. Costs included the cost of allogeneic blood transfusion, setting up the cell saver recovery system, and infusing autologous blood from cell saver, whereas effectiveness measures were allogeneic blood transfusions averted and quality adjusted life years. Results The incremental cost-effectiveness ratio was $55,538 per allogeneic transfusion averted, with a decrease in the transfusion rate from 40.0% to 38.7% associated with the cell saver approach. This translated into an incremental cost-effectiveness ratio of $5,555,380 per quality adjusted life years gained, which is well above the threshold for an intervention to be considered cost-effective ($100,000 per quality adjusted life years gained). Conclusion The use of cell saver during a single-level PLDF does not significantly reduce the need for allogeneic blood transfusion and is not cost-effective. The high cost of cell saver in combination with the low complication rate of allogeneic blood transfusion, suggest that cell saver should not be used for single-level PLDF. Further studies are needed to evaluate the necessity for cell saver among other types of spinal surgery.

Study design Longitudinal cohort. Objectives To determine the discriminate validity of the Short Form-6D (SF-6D) compared with the SF-36 in a cohort of patients with lumbar degenerative disorders. Summary of background data Cost-utility studies are important for the demonstration of comparative effectiveness of treatments for lumbar degenerative disorders. Multidimensional patient-reported outcome tools including the SF-36 and Oswestry Disability Index (ODI) may be limited to measuring the utility of specific health care states. The evaluation of utility is based on single-index preference-based health state scales, such as the SF-6D. The loss of discriminative properties using a single-index compared with a multidimensional score is unknown. Methods The cohort studies included 1104 patients who had decompression and lumbar fusion with complete ODI, SF-36, and SF-6D data at baseline and 2-year follow-up. Discriminative properties of the 3 measures were compared by computing the effect size (ES) and the standardized response mean (SRM). The larger the ES and SRM, the more sensitive to change the measure is. The relative validity (RV) statistic for each measure was also determined with the SF-6D as reference. Measures that are more sensitive than the SF-6D would have RVs greater than 1.0, those that are less sensitive would have RVs less than 1.0. Results The ODI had the greatest ES at 0.93 followed by the SF-6D at 0.88 and the SF-36 Physical Composite Score (PCS) at 0.85. The ODI also had the greatest standardized response mean at 0.73 followed by the SF-6D at 0.70 and the SF-36 PCS at 0.57. The RV statistics for both the ODI (1.28) and the SF-36 PCS (1.32) were greater compared with the SF-6D. The SF-36 bodily pain domain had the greatest ES (1.42), SRM (0.81), and RV (1.50). The general health domain had the lowest ES (0.21) and SRM (0.23), whereas mental health domain had the lowest RV. Conclusions In this cohort of patients, using the single-index SF-6D produces a loss of discriminative properties compared with the SF-36 and ODI. However, this loss is small, because all the effect sizes remain large (≥0.80). Therefore, these losses should not preclude the use of the SF-6D compared with the SF-36 and may be preferred because it is more easily interpretable and less difficult to incorporate in economic evaluations.

STUDY DESIGN Longitudinal cohort. OBJECTIVE To present Oswestry Disability Index scores and SF-6D utility values among patients with different diagnostic etiologies who underwent fusion surgery. SUMMARY OF BACKGROUND DATA Several studies have increased our understanding of health-related quality-of-life measures in patients with low back pain. With rising health care costs, cost-utility analysis is increasingly used by decision makers. Thus, clinicians and researchers need to understand the psychometrics and clinical importance of health state utility values in patients with spine disorders. METHODS A total of 1104 patients who had decompression and lumbar fusion with complete data to compute the SF-6D score at baseline and 2-year follow-up were identified. Primary surgical cases were classified as disc pathology (n = 200), spondylolisthesis (n = 288), instability (n = 43), stenosis (n = 134), or scoliosis (n = 44). Revision cases were classified as nonunion (n = 94), adjacent-level degeneration (n = 98), or postdiscectomy revision (n = 203). Baseline SF-6D and change in SF-6D scores at 2 years were compared among the groups as well as primary versus revision cases. RESULTS There were 674 women and 430 men. The mean age at surgery was 56.65 ± 12.7 years. There were 220 (19.9%) smokers. The worst mean baseline SF-6D score was in patients with nonunion (0.492), followed by disc pathology (0.493), adjacent-level degeneration (0.494), postdiscectomy revision (0.499), stenosis (0.504), instability (0.512), spondylolisthesis (0.520), and scoliosis (0.530). There was a statistically significant difference in baseline SF-6D score among the different groups (P = 0.002). The mean change in SF-6D score was greatest in patients with stenosis (0.088), followed by spondylolisthesis (0.085), scoliosis (0.076), disc pathology (0.076), instability (0.073), postdiscectomy revision (0.070), adjacent-level degeneration (0.066), and nonunion (0.050). There was no statistically significant difference in change in SF-6D score among the different groups (P = 0.096). However, revision cases had statistically significantly smaller gains in SF-6D score (0.064) than primary cases (0.082, P = 0.012). CONCLUSION Patients with lumbar degenerative disorders have health state values similar to patients with chronic renal disease, Crohn's disease, or coronary artery disease. Health state values of patients with different indications for surgery differ at baseline and after surgery. Revision cases have worse baseline SF-6D scores and less improvement in scores at 2 years after surgery than primary cases. Further studies are needed to gain a greater understanding of health state utility values in patients with lumbar degenerative disorders.

Spinal fusion as a treatment for degenerative disc disease is controversial. Prior authors have identified various MRI findings as being pain generators, which might help guide patient selection for lumbar fusion procedures. These findings have included disc desiccation, disc contour, high-intensity zone annular disruption, the presence of Modic endplate changes, and disc space collapse. The purpose of this study is to investigate which MRI findings in patients with degenerative disc disease predict clinical improvement with lumbar fusion.A single-center surgical database of patients undergoing lumbar fusion was reviewed for patients whose indication for fusion surgery was primary disc pathology. We identified 51 patients (71 disc levels) who had completed 2-year prospectively collected outcomes questionnaires and had preoperative MRIs available for review. NRS (0-10) back and leg pain, Oswestry Disability Index (ODI) and SF-36 Physical Composite Summary scores were obtained preoperatively and at 1- and 2-year follow-up. MRIs were reviewed by three fellowship-trained spine surgeons who were asked to grade them for the following five characteristics: (a) disc desiccation, (b) disc contour, (c) presence of a high-intensity zone (HIZ) annular tear, (d) presence of Modic endplate changes and (e) disc height. Two-year outcome measures were compared to MRI findings to identify which findings correlated with improvement in outcome scores.Statistically significant improvements were noted in back pain, leg pain, SF-36 PCS and ODI in the group overall. Disc desiccation, disc contour, presence of an HIZ lesion, and the presence of Modic endplate changes did not correlate with 2-year outcomes. Disc height was correlated with 2-year change in outcome measures. Discs with preoperative height less than 5 mm demonstrated a 23.4 point ODI improvement compared to 9.2 points for discs7 mm. Similarly, SF-36 PCS improved 9.5 points in discs5 mm compared to 0.7 in discs greater than 7 mm. Discs between 5 and 7 mm demonstrated intermediate levels of improvement.Several commonly utilized MRI criteria proposed as indications for lumbar fusion do not seem to correlate with 2-year improvement in clinical outcomes. Discs which are narrowed and collapsed, preoperatively, demonstrate better improvement at 2 years postoperatively as compared to discs which have maintained disc height. Significant disc space collapse may represent a subset of "degenerative disc disease" which responds more favorably to treatment with fusion.