Lumbar Fusion For Degenerative Spondylolisthesis Research Articles

P245. Decompression and fusion for lumbar degenerative spondylolisthesis is associated with higher early morbidity and risk of perioperative complications compared to decompression alone

P245. Decompression and fusion for lumbar degenerative spondylolisthesis is associated with higher early morbidity and risk of perioperative complications compared to decompression alone

The Role of L1PA in Patient-reported Outcomes in Patients Undergoing Single-level Lumbar Fusion for Degenerative Spondylolisthesis.

Retrospective cohort study. To determine whether the L1 pelvic angle (L1PA) can be used to predict quality of life outcomes for adults one year after L4-L5 fusion to treat degenerative spondylolisthesis. L1PA is beneficial in the evaluation of preoperative and postoperative quality of life outcomes in patients undergoing surgery for spinal deformity. No studies have examined its utility in surgical patients with degenerative spinal disease. Patients undergoing L4-L5 posterolateral decompression and fusion or transforaminal lumbar interbody fusion for degenerative lumbar spondylolisthesis were grouped by preoperative and postoperative L1PA, and further stratified by cut offs of >7.2° and <7.2° based on previous literature. We also stratified patients by presence of an ideal calculated L1PA, defined as (0.5×Pelvic incidence) -21 +/-5°, as proposed by prior literature. Preoperative, one-year postoperative and Δ (postoperative minus preoperative) patient-reported outcome measures (PROMs) and radiographic measurements were collected. Twenty-four patients were identified with preoperative L1PAs <7.2° and 132 with L1PAs >7.2°. Eighteen patients were identified with postoperative L1PAs <7.2° and 138 with L1PAs>7.2°. Sixty-five and fifty-seven patients were identified as having ideal calculated preoperative and postoperative L1PAs, respectively. When using absolute cutoffs, L1PA correlated with pelvic tilt, pelvic incidence, and pelvic incidence-lumbar lordosis mismatch (PI-LL). When using calculated L1PAs, L1PA correlated with lumbar lordosis, PI-LL, pelvic tilt and sacral slope. With respect to PROMs, no statistically significant differences existed between cohorts both preoperatively and at one-year postoperatively on either univariate and multivariate analyses. L1PA may be a helpful radiographic consideration that translates to clinically relevant outcomes in spinal deformity. However, it does not appear as predictive of patient outcomes after single-level fusion for patients with L4-L5 degenerative spondylolisthesis. Further studies are warranted to investigate the role of L1PA in degenerative spine patients.

Differences in imaging and clinical characteristics are associated with higher rates of decompression-fusion versus decompression-alone in women compared to men for lumbar degenerative spondylolisthesis.

The goals were to ascertain if differences in imaging/clinical characteristics between women and men were associated with differences in fusion for lumbar degenerative spondylolisthesis. Patients had preoperative standing radiographs, CT scans, and intraoperative fluoroscopic images. Symptoms and comorbidity were obtained from patients; procedure (fusion-surgery or decompression-alone) was obtained from intraoperative records. With fusion surgery as the dependent variable, men and women were compared in multivariable logistic regression models with clinical/imaging characteristics as independent variables. The sample was dichotomized, and analyses were repeated with separate models for men and women. For 380 patients (mean age 67, 61% women), women had greater translation, listhesis angle, lordosis, and pelvic incidence, and less diastasis and disc height (all p ≤ 0.03). The rate of fusion was higher for women (78% vs. 65%; OR 1.9, p = 0.008). Clinical/imaging variables were associated with fusion in separate models for men and women. Among women, in the final multivariable model, less comorbidity (OR 0.5, p = 0.05), greater diastasis (OR 1.6, p = 0.03), and less anterior disc height (OR 0.8, p = 0.0007) were associated with fusion. Among men, in the final multivariable model, opioid use (OR 4.1, p = 0.02), greater translation (OR 1.4, p = 0.0003), and greater diastasis (OR 2.4, p = 0.0002) were associated with fusion. There were differences in imaging characteristics between men and women, and women were more likely to undergo fusion. Differences in fusion within groups indicate that decisions for fusion were based on composite assessments of clinical and imaging characteristics that varied between men and women.

P147. Smoking and spondylolisthesis: assessing the impact of smoking history on patient-reported outcomes following surgical fusion for lumbar degenerative spondylolisthesis

P147. Smoking and spondylolisthesis: assessing the impact of smoking history on patient-reported outcomes following surgical fusion for lumbar degenerative spondylolisthesis

High preoperative expectations and postoperative fulfillment of expectations two years after decompression alone and decompression plus fusion for lumbar degenerative spondylolisthesis

BACKGROUND CONTEXTFulfillment of expectations is a patient-centered outcome that has not been assessed based on fusion status for lumbar degenerative spondylolisthesis (LDS). PURPOSETo compare preoperatively cited expectations and 2-year postoperative fulfillment of expectations between patients undergoing decompression alone (no-fusion) vs. decompression plus fusion (fusion) for LDS. STUDY DESIGNLongitudinal cohort. PATIENT SAMPLEA total of 357 patients. OUTCOME MEASURESPostoperative version of Lumbar Spine Surgery Expectations Survey, Oswestry Disability Index (ODI), satisfaction with surgery. METHODSPreoperatively patients completed the 20-item Expectations Survey measuring amount of ‘improvement expected’ for symptoms, physical function, and psychosocial well-being (score range 0-100); two years postoperatively patients completed the follow-up survey measuring ‘improvement received’. The proportion of expectations fulfilled was calculated as ‘improvement received’ divided by ‘improvement expected’ (<1 some expectations fulfilled, >1 expectations surpassed). Patients also completed the ODI, SF-12 mental health subscale, satisfaction with surgery, and measures of comorbidity and psychosocial status, including social support (ie, help at home) and prior orthopedic surgery (ie, hip/knee arthroplasty). RESULTSPatients’ mean age was 67 years, 61% were women, 82% had single-level LDS, 73% had fusion, and mean follow-up was 26.2 months. Compared to patients with no-fusion, patients with fusion had more pain, spinal instability, use of opioids, disability, and greater preoperative Expectations Survey scores (69 vs 74, p=.008). The proportion of expectations fulfilled postoperatively was high and similar for both groups (.82 vs. .79, p=.40), but more variable for fusion (IQR .32 vs. .40). In multivariable analysis with the proportion as the dependent variable, fulfilled expectations was associated with better mental well-being (coeff=1.1, 95% CI 0.6-1.7, p=.0001) and more social support (coeff=3.3, 95% CI 1.1-5.6, p=.004) and unfulfilled expectations was associated with prior arthroplasty (coeff=-8.6, 95% CI -15.4-(-1.9), p=.01) and subsequent lumbar surgery (coeff=-15.6, 95% CI -25.2-(-6.0), p=.002). Similar associations were found for change in ODI and satisfaction. CONCLUSIONSPatients had high preoperative expectations of surgery with greater expectations for decompression-fusion compared to decompression-alone. Although more variable for the fusion group, both groups had high proportions of expectations fulfilled. This study highlights the spectrum of clinical and psychosocial variables that impacts fulfillment of expectations for both decompression-alone and decompression-fusion for LDS surgery.

Over level prophylactic flavectomy in lumbar fusion for degenerative spondylolisthesis: does it influence the rates of adjacent segment disease and clinical outcomes?

Over level prophylactic flavectomy in lumbar fusion for degenerative spondylolisthesis: does it influence the rates of adjacent segment disease and clinical outcomes?

The concept of recovery kinetics: an observational study of continuous post-operative monitoring in spine surgery.

The spine surgeon's understanding of an individual patient's burden of disease and functional disability in daily life is shaped by patient-reported outcome measures (PROMs). Although PROMs are useful in understanding the patient's perception of their disease, the use of PROMs constitutes a "snapshot" approach of single timepoint data capture, omitting day-to-day fluctuations in functional status. We introduce the concept of kinetics when considering continuous and objective postoperative patient monitoring with wearable sensors. A prospective single-centre series was performed using patients either undergoing lumbar decompression for lumbar spinal stenosis (LSS) (n=12), or posterior lumbar fusion for degenerative spondylolisthesis (n=12). The Oswestry Disability Index (PROM) was conducted preoperatively and 12-weeks postoperatively. During this timeframe, continuous measurements of step count and distance travelled were made using a wrist-based wearable accelerometer. Over the 12-week study period, mean daily step count for all participants improved from 4,700 to 7,700 steps per day (P=0.013), following an initial dip in total steps taken. The mean daily distance travelled improved from 3,300 to 5,300 meters per day (P=0.003). Decompression group recovered at a faster rate than the fusion group. Although overall improvement was similar between the decompression and fusion groups, the recovery kinetics varied. The recovery kinetics approach of continuous postoperative monitoring provides additional insight to postoperative patient progress.

Adjacent segment pathology following posterior lumbar interbody fusion for lumbar degenerative spondylolisthesis: a comparison between minimally invasive and conventional open approach

The minimally invasive (MI) approach in posterior lumbar interbody fusion (PLIF) minimizes the muscle-stripping posterior exposure of the lumbar spine; therefore, it is hypothesized that such benefits would reduce adjacent segment pathology (ASP) development. This study aimed to estimate the incidence of ASP following MI-PLIF. Retrospective study. A total of 100 patients who had undergone single-level PLIF at the L4/5 level for lumbar degenerative spondylolisthesis were retrospectively studied (MI-PLIF group: 68 patients; conventional open PLIF [O-PLIF] group; 32 patients; average follow-up period: 100.5 months). Incidence of ASP. Patients were considered to have operative ASP (OASP) if adjacent segments manifested degenerative lesions that caused clinically significant symptoms requiring surgery. Survival curves were estimated for each group using the Kaplan-Meier method. The study was not externally funded. The authors have no conflicts of interest to declare. Four (5.9%) of the 68 patients in the MI-PLIF group and 6 (18.8%) of the 32 patients in the O-PLIF group experienced OASP during the follow-up period. Kaplan-Meier analysis predicted a disease-free OASP survival rate of 98.5% (95% confidence interval [CI], 95.5%-100%) in the MI-PLIF group and 90.6% (95% CI, 81.1%-100%) in the O-PLIF group at 5 years, and 93.7% (95% CI, 86.8%-100%) in the MI-PLIF group and 71.8% (95% CI, 52.9%-97.5%) in the O-PLIF group at 10 years. MI-PLIF achieved a significantly higher survival rate in OASP than did O-PLIF (p=.04). O-PLIF was associated with a 3.97 times higher risk (odds ratio 3.97, 95% CI, 1.02-15.48; p=.04) of developing OASP in our cohort. Following MI-PLIF, the rate of OASP was predicted to be 1.5% at 5 years and 6.3% at 10 years. MI-PLIF had a lower incidence of OASP and more favorable clinical outcomes than did O-PLIF.

The patient acceptable symptom state for the Oswestry Disability Index following single-level lumbar fusion for degenerative spondylolisthesis

The patient acceptable symptom state (PASS) is a valuable tool for interpreting patient-reported outcomes. Previous studies have attempted to define the PASS in a heterogenous cohort with various lumbar spinal disorders and surgical procedures. We aimed to determine the PASS threshold for the Oswestry Disability Index (ODI) specifically for patients undergoing lumbar fusion for spondylolisthesis-associated functional disability. Retrospective review of prospectively collected registry data. There were 692 patients who underwent primary single-level minimally invasive transforaminal lumbar interbody fusion for degenerative spondylolisthesis between 2006 and 2014. The ODI was collected pre-operatively, at 6 months and 2 years postoperatively. An anchor question was adapted from the NASS questionnaire, "How would you rate the overall results of your treatment?" while a validation question was taken from the same questionnaire, "Has the surgery for your back condition met your expectations so far?" Responses to the anchor question were used to determine whether a PASS was achieved. Receiver operating characteristics curve analysis was performed to assess the ability of the ODI to discriminate between an acceptable/unacceptable symptom state as well as to define PASS thresholds. Sensitivity analyses were performed for different follow-up periods (6 months, 2 years), subgroups (by age, gender, BMI, and comorbidity burden), baseline ODI tertiles, and an alternate definition of PASS. In total, 529 of 692 (76%) patients completed 2-year follow-up, of which, 89% considered their symptom state to be acceptable. Areas under the curve (AUC) ranged from 0.81 to 0.90 for all receiver operating characteristics analyses, indicating that the ODI had an excellent discriminative ability. The PASS threshold was ≤18.09 at 6 months (AUC 0.81, sensitivity 77%, specificity 72%) and ≤15.27 at 2 years (AUC 0.86, sensitivity 79%, specificity 79%). These thresholds proved to be robust in the sensitivity analyses, showing minimal variation across different patient subgroups and baseline score tertiles. Patients with an ODI of ≤15.27 can be considered to have achieved a PASS after lumbar fusion for degenerative spondylolisthesis. These findings will help surgeons to contextualize a patient's functional recovery after lumbar spine surgery and enable researchers to define clinically relevant benchmarks when designing trials utilizing the ODI.

Patient Reported Outcome Analysis after Posterior Decompression and Posterolateral Fusion Surgery in Lumbar Degenerative Spondylolisthesis

Introduction: Lumbar degenerative spondylolisthesis is an acquired slippage of a vertebra due to degenerative arthritis of the facet joints without any defect in the vertebral ring. Degenerative spondylolisthesis is commonly treated with posterior decompression and posterolateral fusion. This study aims to evaluate the clinical outcome of posterior decompression and instrumented posterolateral fusion surgery by analysing patient reported outcome measures.&#x0D; Materials and Methods: A retrospective study in which patients who had posterior decompression and instrumented posterolateral fusion for lumbar degenerative spondylolisthesis between September 2017 and August 2019 at Nepal Mediciti Hospital were included in the study. Other types of spondylolisthesis managed with similar technique and patients who had follow up period of less than three months were excluded. Functional outcome was assessed by comparing pre and post-operative patient reported outcome measures: VAS leg pain, VAS back pain and Oswestry Disability Index (ODI). The paired t-test was used for statistical analysis.&#x0D; Results: Of the 16 patients, 81.25% were female. Mean age and mean follow up period were 58.81± 10.47 years and 13.56±7.15 months respectively. Seventy five percent had grade I spondylolisthesis. Most common level of spondylolisthesis was L4/5 (62.5%). Fourteen patients reported improvement in their symptoms after surgery. The changes in functional outcome scores between baseline and at follow up evaluation were as follows: 32.70 ± 17.44 points for ODI, 3 ±1.89 for VAS leg pain, and 5.37 ± 2.36 for VAS back pain (P&lt;0.001). Superficial wound infection was the most common complication observed in 18.3%.&#x0D; Conclusion: In our case series, 87.5% had improvement in their symptoms after surgery. The change in mean score of patients’ reported outcome measures before and after surgery was statistically significant. We recommend a prospective comparative study between decompression alone and the fusion technique for the evaluation of long term functional outcome.

Predicting spondylolisthesis correction with prone traction radiographs

To determine the effectiveness of prone traction radiographs in predicting postoperative slip distance, slip angle, changes in disc height, and lordosis after surgery for degenerative spondylolisthesis of the lumbar spine. A total of 63 consecutive patients with a degenerative spondylolisthesis and preoperative prone traction radiographs obtained since 2010 were studied. Slip distance, slip angle, disc height, segmental lordosis, and global lordosis (L1 to S1) were measured on preoperative lateral standing radiographs, flexion-extension lateral radiographs, prone traction lateral radiographs, and postoperative lateral standing radiographs. Patients were divided into two groups: posterolateral fusion or posterolateral fusion with interbody fusion. The mean changes in segmental lordosis and global lordosis were 7.1° (SD 6.7°) and 2.9° (SD 9.9°) respectively for the interbody fusion group, and 0.8° (SD 5.1°) and -0.4° (SD 10.1°) respectively for the posterolateral fusion-only group. Segmental lordosis (ρ = 0.794, p < 0.001) corrected by interbody fusion correlated best with prone traction radiographs. Global lumbar lordosis (ρ = 0.788, p < 0.001) correlated best with the interbody fusion group and preoperative lateral standing radiographs. The least difference in slip distance (-0.3 mm (SD 1.7 mm), p < 0.001), slip angle (0.9° (SD 5.2°), p < 0.001), and disc height (0.02 mm (SD 2.4 mm), p < 0.001) was seen between prone traction and postoperative radiographs. Regression analyses suggested that prone traction parameters best predicted correction of slip distance (Corrected Akaike's Information Criterion (AICc) = 37.336) and disc height (AICc = 58.096), while correction of slip angle (AICc = 26.453) was best predicted by extension radiographs. Receiver operating characteristic (ROC) cut-off showed, with 68.3% sensitivity and 64.5% specificity, that to achieve a 3.0° increase in segmental lordotic angle, patients with a prone traction disc height of 8.5 mm needed an interbody fusion. Prone traction radiographs best predict the slip distance and disc height correction achieved by interbody fusion for lumbar degenerative spondylolisthesis. To achieve this maximum correction, interbody fusion should be undertaken if a disc height of more than 8.5 mm is attained on preoperative prone traction radiographs. Level of Evidence: Level II Prognostic Study Cite this article: Bone Joint J 2020;102-B(8):1062-1071.

CORR Insights®: What Are the Patient-reported Outcomes, Complications, and Radiographic Results of Lumbar Fusion for Degenerative Spondylolisthesis in Patients Younger Than 50 Years?

CORR Insights®: What Are the Patient-reported Outcomes, Complications, and Radiographic Results of Lumbar Fusion for Degenerative Spondylolisthesis in Patients Younger Than 50 Years?

What Are the Patient-reported Outcomes, Complications, and Radiographic Results of Lumbar Fusion for Degenerative Spondylolisthesis in Patients Younger Than 50 Years?

The number of young patients with degenerative lumbar spondylosis is expected to increase, and with it, the number of younger patients seeking surgical treatment is likely to rise. The goals of young patients with degenerative spondylolisthesis may differ from those of older patients, but little is known about the levels of pain and function, complication rates, or radiographic union that young patients achieve after interbody fusion. (1) How likely were patients younger than 50 years to achieve a minimal clinically important difference (MCID) in improvement on any of several validated patient-reported outcomes scores after transforaminal lumbar interbody fusion for degenerative spondylolisthesis at a minimum of 2 years after surgery? (2) What proportion developed complications or underwent reoperations? (3) What proportion achieved radiographic fusion or developed adjacent-segment degeneration? Longitudinally maintained institutional registry data of patients undergoing primary, single-level, transforaminal lumbar interbody fusion for degenerative spondylolisthesis at a single institution from 2006 to 2013 were studied in this retrospective case series. Of the 96 patients who met inclusion criteria, 14% (13 of 96) were missing follow-up data, leaving 83 patients younger than 50 years with complete clinical and radiological data at a minimum of 2 years (97%, 93 of 96 had sufficient data to assess complications and radiographic fusion). The mean age of the cohort was 44 ± 7 years. Radiological parameters for each patient with spondylolisthesis were recorded. Clinical outcomes such as the numeric rating scale for back pain and leg pain, Oswestry Disability Index (ODI) and SF-36 were assessed preoperatively and postoperatively at 1, 3, 6 months and 2 years. The proportion of patients who had an improvement greater than the MCID of each outcome instrument was then calculated. The occurrence of any medical, surgical or wound complications, and reoperations for any reason were recorded. Radiographic fusion using Bridwell grading and adjacent-segment degeneration were assessed by an independent observer not involved in clinical care. The mean follow-up was 5 ± 3 years. The proportions of patients younger than 50 years who achieved the MCID for the various patient-reported outcomes were 82% (68 of 83) for leg pain, 75% (62 of 83) for back pain, 87% (72 of 83) for ODI and 71% (59 of 83) for SF-36 physical component summary at 2 years. Two perioperative complications occurred, and two reoperations were performed for implant-related complications. A total of 85% (79 of 93) of young patients achieved stable fusion, 8% (seven of 93) had radiologic adjacent-segment degeneration, and one patient underwent a revision procedure. Young patients with lumbar degenerative spondylolisthesis commonly, but do not always, experience clinically meaningful gains in pain relief, function, and quality of life after transforaminal lumbar interbody fusion. A low risk of complications, reoperations, nonunion and adjacent-segment degeneration were also noted in this population. Level III, therapeutic study.

Factors Associated with 12-month Return to Work Following One-level Posterior Lumbar Fusion for Grade 1 Degenerative Spondylolisthesis: An Analysis of the Quality Outcomes Database

Abstract INTRODUCTION Return to work (RTW) has become an increasingly important metric of spinal surgery success. Lumbar spondylolisthesis is a relatively common spinal pathology that may manifest as low back pain and/or leg pain, causing functional disability and hindering patients from working and performing activities of daily living. Currently, there is a lack of nationwide data evaluating RTW in lumbar spondylolisthesis. METHODS We queried the Quality Outcomes Database for employed patients that underwent single-level posterior spinal fusion for Meyerding grade I degenerative lumbar spondylolisthesis. We compared cases who returned to work within 12 mo with regard to baseline demographics, comorbidities, clinical characteristics, and patient reported outcomes. A multivariable logistic regression model was fitted for 12-mo RTW adjusting for an array of pre- and intraoperative variables. RESULTS A total of 163 patients with available 12-mo follow-up data (84%) were analyzed. Median age was 57 yr (interquartile range: 51-60 yr) and 57% were females (n = 93). On multivariable analysis, patients that were working at the time of surgery were significantly more likely to RTW compared to those that were not working (OR 4.62, 95% CI 1.42-15.07, P &lt; .001). In addition, college education (OR 3.30, 95% CI 1.18-9.24, P = .02) was associated with significantly higher odds of returning to work compared to high-school or less education. The effect of postcollege education (OR 5.27, 95% CI 1.46-19.05, P = .01), baseline ODI score (OR 0.64, 95% CI 0.34 - 1.21, P = .17) and smoking status (OR 0.45, 95% CI 0.13-1.54, P = .20) were not found to be significant. Model c-statistic was 0.76. CONCLUSION Analysis of data from a national spinal registry revealed that employment status at the time of surgery and education level were the most significant predictors of 12-moh RTW for patients undergoing single-level posterior lumbar fusion for degenerative spondylolisthesis. The findings of the present study may assist surgeons and patients with setting realistic treatment expectations during preoperative discussions.

Sarcopenia does not affect clinical outcomes following lumbar fusion

Sarcopenia, defined as decreased skeletal muscle mass or function, has recently been found to have increased perioperative morbidity and mortality. The relationship between sarcopenia and clinical outcomes in patients undergoing lumbar fusion has not been examined. This study investigates whether sarcopenia affects fusion rates and outcomes following single-level lumbar decompression and fusion. A retrospective analysis was undertaken of 97 consecutive patients who underwent a single level lumbar fusion for degenerative spondylolisthesis. Demographics, perioperative data, and patient reported clinical outcomes were collected. Measurements of paraspinal muscle CSA were made using a standardized protocol at the level of the L3-4 disc space on a preoperative lumbar MRI. Univariate analysis was used to compare cohorts with regards to demographics, comorbidities, and clinical outcomes. Of 97 patients, 16 patients (15.8%) were in the sarcopenic cohort utilizing a threshold of 986.1 mm2/m2. Reoperation rates were not significantly different between the two groups (0% vs 3.6%, p = .451). The sarcopenia cohort had lower BMI (28.1 vs 31.8, p = .017) and less male patients (6.3% vs 55.6%, p < .001). Mean follow-up was 18.3 months. There was no significant difference in postoperative Oswestry Disability Index (ODI) (24.7 vs 23.2, p = .794) Short Form 12 Physical (38.0 vs. 40.4, p = .445) Mental scores (55.5 vs. 53.6, p = .503), or visual analog scale (VAS) back pain scores (3.4 vs. 3.3, p = .818). No significant difference was found with regards to outcomes when comparing sarcopenic to non-sarcopenic patients undergoing lumbar fusion. Sarcopenia does not impact the clinical success of lumbar fusion for degenerative spondylolisthesis.

Does Diabetes Mellitus Affect Lumbar Paraspinal Muscle Morphometry

Background: Changes in paraspinal muscle cross-sectional surface area (CSA) have been shown to occur in patients with chronic and acute low back pain. Numerous factors can affect muscle density; however, the relationship between metabolic disease, such as type II diabetes mellitus (DM) and lumbar paraspinal morphometry, has not been examined. Therefore, we set out to compare paraspinal CSA in diabetic patients undergoing lumbar fusion to patients without diabetes. Methods: A retrospective review of 101 patients, who underwent posterior lumbar fusion for degenerative spondylolisthesis, was performed. Data collected included preoperative Oswestry Disability Index, SF-12 physical and mental health scores, and visual analog scale for back pain. Utilizing standard measurement software for the iliocostalis, longissimus, multifidus, and psoas muscles, individual paraspinal muscle CSA was measured on preoperative magnetic resonance imaging. Average CSA measurements were then compared between diabetic and non-diabetic patients utilizing Student’s t-test. Results: Thirteen patients were included in the DM group while 88 composed the non-DM group. There were no differences in age or body mass index between the groups. There were no significant differences in preoperative health-related outcome scores. Average psoas muscle iliocostalis as well as multifidus CSA were not significantly different between the non-DM and DM groups (p=0.09, 0.263, 0.458). The longissimus CSA was significantly decreased in the DM group compared to the non-DM (p=0.004). Conclusions: This study shows that type II DM is associated with decreased paraspinal muscle CSA, but this finding was specific to the longissimus muscle. Our findings suggest that metabolic factors may play an important role in the maintenance of paraspinal muscle balance.

Friday, September 28, 2018 1:00 PM–2:30 PM abstracts: a new look at imaging: 210. Severe lumbar disability is associated with decreased psoas cross sectional area in degenerative spondylolisthesis

BACKGROUND CONTEXT There has been increasing interest in examining the relationship of lumbar paraspinal muscle morphometry and outcomes after lumbar spinal surgery, as well as investigating any association between changes in paraspinal muscle density and low back pain.However, the relationship of the iliopsoas muscle to the posterior paraspinal muscles, and the effect of variation in psoas cross sectional area to lumbar disability in patients with degenerative spondylolisthesis, has not been extensively explored. PURPOSE We set out to compare the absolute psoas and paraspinal CSA in patients with degenerative lumbar spondylolisthesis and corresponding severe disability to similar patients with only mild or moderate disability. STUDY DESIGN/SETTING Retrospective cohort. PATIENT SAMPLE Inclusion criteria were any patient undergoing single level lumbar fusion for degenerative spondylolisthesis greater than 18 years of age at one institution, based on the ICD-9 code 721.42, with a preoperative lumbar spine MRI and completed preoperative patient-reported outcome scores. Patients under the age of 18 years, those lacking a preoperative lumbar spine MRI or completed preoperative patient-reported outcome scores, or those with a diagnosis other than degenerative lumbar spondylolisthesis were excluded from the study. METHODS We retrospectively reviewed the medical records of 101 patients undergoing lumbar fusion for degenerative spondylolisthesis. Patients were divided into Oswestry Disability Index (ODI) score 40 (severe disability, SD) groups. The total CSA of the psoas and paraspinal muscles were measured on preoperative magnetic resonance imaging (MRI). Student's t-test was used to compare continuous variables between groups. Multivariable logistic regression was performed analyzing the effects of ASA class, history of heart disease, smoking status and psoas CSA on lumbar disability. P RESULTS There were 37 patients in the SD group and 64 in the MMD group. Average age and body mass index were similar between groups. For the paraspinal muscles, average iliocostalis CSA was 1093.5mm2 versus 1192.2mm2 for the SD group versus the MMD group, respectively (p=.168). Similarly, the longissimus CSA was 685.8mm2 versus 764.8mm2 (p=.329), respectively, and the multifidus CSA was 499.1mm2 versus 526.0mm2 (p=.125), respectively. Psoas muscle CSA was significantly decreased in the SD group compared to the MMD group (1010.08mm2 vs. 1178.6mm2, p=.041). Multivariable logistic regression demonstrated that active smoking was independently associated with severe disability (OR=12.9, range: 1.19–140.2, p=.035), while psoas size in the upper quartile was significantly protective against severe disability (OR=0.13, range: 0.03–0.66, p=.013). CONCLUSIONS In patients with severe lumbar disability and a diagnosis of degenerative spondylolisthesis, when compared to similar patients with mild or moderate disability, we found significantly decreased absolute cross sectional area of the psoas muscle. In addition, multivariate analysis found that increased psoas CSA was significantly protective against severe lumbar disability. Our findings are suggestive of a potential association between psoas atrophy and worsening severity of lumbar disability.

Wednesday, September 26, 2018 10:35 AM – 12:00 PM Understanding Lumbar Stenosis/Spondylolisthesis: 13. Unilateral laminotomy for bilateral decompression versus decompression with instrumented fusion for lumbar degenerative spondylolisthesis at five-year follow-up

BACKGROUND CONTEXT Controversy exists regarding whether fusion should be used to augment decompression surgery in patients with symptomatic lumbar spinal stenosis with grade I/II (low-grade), stable degenerative spondylolisthesis. For years, the standard has been fusion with laminectomy in order to prevent postoperative instability. However, instability and reoperations may be reduced or prevented using less invasive, structure sparing decompression techniques without the need for fusion. PURPOSE To compare reoperation rates within a 5-year follow-up period of unilateral laminotomy for bilateral decompression (ULBD) versus posterior lumbar decompression with instrumented fusion (fusion) for patients with degenerative spondylolisthesis with spinal stenosis in a multicenter database. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE A final cohort of 601 Kaiser Permanente Northern California members with diagnoses of lumbar degenerative spondylolisthesis and lumbar spinal stenosis of whom 164 patients underwent ULBD and 437 underwent fusion between January 2007 and December 2011. OUTCOME MEASURES The primary outcome measure was reoperation rate at 5-year postoperative follow-up. Secondary outcome measures included blood loss during surgery, length of stay, reoperation type, reoperation level, and 90-day postoperative complication rates. METHODS We identified 164 patients with lumbar degenerative spondylolisthesis and lumbar stenosis who underwent ULBD between January 2007 and December 2011. These patients were propensity score matched on age at surgery, gender, race and smoking status with patients who underwent fusion (n=437). The primary outcome was 5-year reoperation rate and secondary outcome measures included postoperative complication rates, reoperation type, reoperation level, blood loss during surgery, and length of stay. RESULTS The reoperation rate within 5-year follow-up was significantly lower at 10.4% in the ULBD group compared to 17.2% in the fusion group (p=.0393). Type of reoperation was similar between the two groups. Reoperation at the index or adjacent level was not significant different between the two groups. Patients that underwent ULBD had significantly less mean estimated blood loss compared to fusion (82 vs. 445 ml, p CONCLUSIONS For patients with stable degenerative spondylolisthesis and lumbar stenosis, ULBD is a viable, durable option compared to fusion with a lower reoperation rate within a 5-year follow-up period, as well as decreased blood loss and length of stay. Further prospective studies are required to determine the optimal clinical scenario for ULBD in the setting of degenerative spondylolisthesis. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P28. Does diabetes mellitus affect lumbar paraspinal muscle morphometry?

BACKGROUND CONTEXT Changes in paraspinal muscle cross-sectional surface area (CSA) have been shown to occur in patients with chronic and acute low back pain. Numerous factors can affect muscle density; however, the relationship between metabolic disease, such as type II diabetes mellitus (DM) and lumbar paraspinal morphometry, has not been examined. Therefore, we set out to compare paraspinal CSA in diabetic patients undergoing lumbar fusion to patients without diabetes. PURPOSE To investigate the association between type II diabetes and lumbar musculature sarcopenia. STUDY DESIGN/SETTING Retrospective cohort. PATIENT SAMPLE Retrospective review of patients with degenerative spondylolisthesis undergoing single-level lumbar fusion. METHODS A retrospective review of 101 patients, who underwent posterior lumbar fusion for degenerative spondylolisthesis, was performed. Data collected included preoperative Oswestry Disability Index (ODI), SF-12 physical and mental health scores, and visual analog scale (VAS) for back pain. Utilizing standard measurement software for the iliocostalis, longissimus, multifidus, and psoas muscles, individual paraspinal muscle CSA was measured on preoperative magnetic resonance imaging (MRI). Average CSA measurements were then compared between diabetic and nondiabetic patients utilizing Student's t-test. RESULTS Thirteen patients were included in the DM group while 88 composed the nonDM group. There were no differences in age or body mass index (BMI) between the groups. There were no significant differences in preoperative ODI, VAS back pain scores, or SF-12 mental or physical health scores. Average psoas muscle CSA was not significantly different between the groups (1091.5 mm2 vs. 938.3 mm2 for nonDM vs. DM, respectively, p=.09). Iliocostalis CSA was 1145.3 mm2 and 1023.5 mm2 for the nonDM and DM groups, respectively (p=.263). The multifidus CSA was 513.4 mm2 and 478.9 mm2 for the nonDM and DM groups, respectively (p=.458). The longissimus CSA was significantly decreased in the DM group, with an average surface area of 574.8 mm2 when compared to, 724.3 mm2 for the nonDM (p=.004). CONCLUSIONS This study is the first to establish that type II DM is associated with decreased paraspinal muscle CSA, but this finding was specific to the longissimus muscle. There is increasing evidence that changes in paraspinal morphometry are implicated in the development of chronic LBP, and our findings suggest that metabolic factors may play an important role in the maintenance of paraspinal muscle balance.

Severe Lumbar Disability Is Associated With Decreased Psoas Cross-Sectional Area in Degenerative Spondylolisthesis.

Study Design:Retrospective cohort.Objectives:Alterations in lumbar paraspinal muscle cross-sectional area (CSA) may correlate with lumbar pathology. The purpose of this study was to compare paraspinal CSA in patients with degenerative spondylolisthesis and severe lumbar disability to those with mild or moderate lumbar disability, as determined by the Oswestry Disability Index (ODI).Methods:We retrospectively reviewed the medical records of 101 patients undergoing lumbar fusion for degenerative spondylolisthesis. Patients were divided into ODI score ≤40 (mild/moderate disability, MMD) and ODI score >40 (severe disability, SD) groups. The total CSA of the psoas and paraspinal muscles were measured on preoperative magnetic resonance imaging (MRI).Results:There were 37 patients in the SD group and 64 in the MMD group. Average age and body mass index were similar between groups. For the paraspinal muscles, we were unable to demonstrate any significant differences in total CSA between the groups. Psoas muscle CSA was significantly decreased in the SD group compared with the MMD group (1010.08 vs 1178.6 mm2, P = .041). Multivariate analysis found that psoas CSA in the upper quartile was significantly protective against severe disability (P = .013).Conclusions:We found that patients with severe lumbar disability had no significant differences in posterior lumbar paraspinal CSA when compared with those with mild/moderate disability. However, severely disabled patients had significantly decreased psoas CSA, and larger psoas CSA was strongly protective against severe disability, suggestive of a potential association with psoas atrophy and worsening severity of lumbar pathology.