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OBJECTIVELumbar fusion can lead to significant improvements in patient-reported outcomes (PROs) in patients with degenerative conditions. It is unknown whether the presence of hip or knee arthritis confounds the responses of patients to low-back–specific PROs. This study examined PROs with lumbar fusion in patients with concomitant lower-extremity arthritis. The purpose of the current study was to examine whether patients with significant lower-extremity arthritis who undergo lumbar fusion achieve similar improvements in low-back–specific PROs compared to patients without lower-extremity arthritis.METHODSPatients were identified from a prospectively enrolled multicenter registry of patients undergoing lumbar fusion surgery for degenerative conditions. Two hundred thirty patients identified with lumbar fusion and who also had concomitant lower-extremity arthritis were propensity matched to 233 patients who did not have lower-extremity arthritis based on age, BMI, sex, smoking status, American Society of Anesthesiologists grade, number of levels fused, and surgical approach. One-year improvement in PROs, numeric rating scales (0–10) for back and leg pain, and the Oswestry Disability Index and EuroQol-5D scores were compared for patients with and without lower-extremity arthritis.RESULTSBaseline demographics and preoperative outcome measures did not differ between the two propensity-matched groups with 110 cases each. Patients with concomitant lower-extremity arthritis achieved similar improvement in health-related quality-of-life measures to patients without lower-extremity arthritis, with no significant differences between the groups (p > 0.10).CONCLUSIONSThe presence of lower-extremity arthritis does not adversely affect the results of lumbar fusion in properly selected patients. Patients with lower-extremity arthritis who undergo lumbar fusion can achieve meaningful improvement in PROs similar to patients without arthritis.

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

OBJECTIVEUnexpected nonhome discharge causes additional costs in the current reimbursement models, especially to the payor. Nonhome discharge is also related to longer length of hospital stay and therefore higher healthcare costs to society. With increasing demand for spine surgery, it is important to minimize costs by streamlining discharges and reducing length of hospital stay. Identifying factors associated with nonhome discharge can be useful for early intervention for discharge planning. The authors aimed to identify the drivers of nonhome discharge in patients undergoing 1- or 2-level instrumented lumbar fusion.METHODSThe electronic medical records from a single-center hospital administrative database were analyzed for consecutive patients who underwent 1- to 2-level instrumented lumbar fusion for degenerative lumbar conditions during the period from 2016 to 2018. Discharge disposition was determined as home or nonhome. A logistic regression analysis was used to determine associations between nonhome discharge and age, sex, body mass index (BMI), race, American Society of Anesthesiologists grade, smoking status, marital status, insurance type, residence in an underserved zip code, and operative factors.RESULTSA total of 1502 patients were included. The majority (81%) were discharged home. Factors associated with a nonhome discharge were older age, higher BMI, living in an underserved zip code, not being married, being on government insurance, and having more levels fused. Patients discharged to a nonhome facility had longer lengths of hospital stay (5.6 vs 3.0 days, p < 0.001) and significantly increased hospital costs ($21,204 vs $17,518, p < 0.001).CONCLUSIONSIncreased age, greater BMI, residence in an underserved zip code, not being married, and government insurance are drivers for discharge to a nonhome facility after a 1- to 2-level instrumented lumbar fusion. Early identification and intervention for these patients, even before admission, may decrease the length of hospital stay and medical costs.

OBJECTIVEPosterior fixation with interbody cage placement can be accomplished via numerous techniques. In an attempt to expedite recovery by limiting muscle dissection, midline lumbar interbody fusion (MIDLIF) has been described. More recently, the authors have developed a robot-assisted MIDLIF (RA-MIDLIF) technique. The purpose of this study was to compare the index episode-of-care (iEOC) parameters between patients undergoing traditional open transforaminal lumbar interbody fusion (tTLIF), MIDLIF, and RA-MIDLIF.METHODSA retrospective review of a prospective, multisurgeon surgical database was performed. Consecutive patients undergoing 1- or 2-level tTLIF, MIDLIF, or RA-MIDLIF for degenerative lumbar conditions were identified. Patients in each cohort were propensity matched based on age, sex, smoking status, BMI, diagnosis, American Society of Anesthesiologists (ASA) class, and number of levels fused. Index EOC parameters such as length of stay (LOS), estimated blood loss (EBL), operating room (OR) time, and actual, direct hospital costs for the index surgical visit were analyzed.RESULTSOf 281 and 249 patients undergoing tTLIF and MIDLIF, respectively, 52 cases in each cohort were successfully propensity matched to the authors’ first 55 RA-MIDLIF cases. Consistent with propensity matching, there was no significant difference in age, sex, BMI, diagnosis, ASA class, or levels fused. Spondylolisthesis was the most common indication for surgery in all cohorts. The mean total iEOC was similar across all cohorts. Patients undergoing RA-MIDLIF had a shorter average LOS (1.53 days) than those undergoing either MIDLIF (2.71 days) or tTLIF (3.58 days). Both MIDLIF and RA-MIDLIF were associated with lower EBL and less OR time compared with tTLIF.CONCLUSIONSDespite concerns for additional cost and time while introducing navigation or robotic technology, a propensity-matched comparison of the authors’ first 52 RA-MIDLIF surgeries with tTLIF and MIDLIF showed promising results for reducing OR time, EBL, and LOS without increasing cost.

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.

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.

OBJECTIVEThe goal of this study was to determine efficacy and cost-effectiveness of Cell Saver in 2- and 3-level lumbar decompression and fusion.METHODSPatients seen at a tertiary care spine center who were undergoing a posterior 2- or 3-level lumbar decompression and fusion were randomized to have Cell Saver used during their surgery (CS group, n = 48) or not used (No Cell Saver [NCS] group, n = 47). Data regarding preoperative and postoperative hemoglobin and hematocrit, estimated blood loss, volume of Cell Saver blood reinfused, number of units and volume of allogeneic blood transfused intraoperatively and postoperatively, complications, and costs were collected. Costs associated with Cell Saver use were calculated based on units of allogeneic blood transfusions averted.RESULTSDemographics and surgical parameters were similar in both groups. The mean estimated blood loss was similar in both groups: 612 ml in the CS group and 742 ml in the NCS group. There were 53 U of allogeneic blood transfused in 29 patients in the NCS group at a total blood product cost of $67,688; and 38 U of allogeneic blood transfused in 16 patients in the CS group at a total blood cost of $113,162, resulting in a cost of $3031 per allogeneic blood transfusion averted using Cell Saver.CONCLUSIONSCell Saver use produced lower rates of allogeneic transfusion but was found to be more expensive than using only allogeneic blood for 2- and 3-level lumbar degenerative fusions. This increased cost may be reasonable to patients who perceive that the risks associated with allogeneic transfusions are unacceptable.■ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: randomized controlled trial; evidence: class III.

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 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.

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.