Does the Number of Levels Fused Affect Spinopelvic Parameters and Clinical Outcomes Following Posterolateral Lumbar Fusion for Low-Grade Spondylolisthesis?

STUDY DESIGN: Retrospective cohort. OBJECTIVES: To determine how the number of fused intervertebral levels affects radiographic parameters and clinical outcomes in patients undergoing open posterolateral lumbar fusion (PLF) for low-grade degenerative spondylolisthesis. METHODS: This was a retrospective cohort study on patients who underwent open PLF for low-grade spondylolisthesis at a single institution from 2011 to 2018. Patients were divided into groups based on number of levels fused during their procedure (1, 2, or 3 or more). Preoperative and postoperative spinopelvic radiographic parameters, patient-reported outcomes (Visual Analog Scale [VAS]-back, VAS-leg, Oswestry Disability Index [ODI]), and postoperative complications were compared. RESULTS: Of the 316 patients eligible (203 one-level, 95 two-level, 18 three or more levels), change in initial postoperative to final pelvic incidence-lumbar lordosis was greatest in 2-level fusions (P = .039), while 3 or more level fusions had worse final pelvic tilt measures (P = .021). In addition, multilevel fusions had worse final VAS-back scores (2-level: P = .015; 3 or more levels: P = .011), higher rates of dural tears (2-level: P = .001), reoperation (2-level: P = .039), and discharge to facility (3 or more levels: P = .047) when compared with 1-level fusions. CONCLUSIONS: Patients in multilevel fusions experienced less improvement in back pain, had more complications, and were more commonly discharged to a facility compared with single-level PLF patients. These findings are important for operative planning, for setting appropriate preoperative expectations, and for risk stratification in patients undergoing posterior lumbar fusion for low-grade spondylolisthesis.

High-Grade Spondylolisthesis in Adults: Current Concepts in Evaluation and Management.

BACKGROUND: Information regarding the treatment of high-grade spondylolisthesis (HGS) in adults has been previously described; however, previous descriptions of the evaluation and surgical management of HGS do not represent more recent and now established approaches. The purpose of the current review is to discuss current concepts in the evaluation and management of patients with HGS. METHODS: Literature review. RESULTS: HGS is diagnosed in up to 11.3% of adults with spondylolisthesis and typically presents as nonspecific lower back pain. Regarding evaluation, a thorough history and physical examination should be performed, which may help predict the presence of HGS. Diagnostic imaging, and specifically the use of spino-pelvic parameters, are now commonly implicated in guiding treatment course and prognosis. When surgical intervention is indicated, surgical approaches include in situ fusion variations, reduction and partial reduction with fusion, and vertebrectomy. Although the majority of studies suggest improvements with these approaches, the literature is limited by a low level of evidence with regards to the superiority of one technique when compared with others. CONCLUSIONS: HGS is a unique cause of low back pain in adults that carries considerable morbidity, but rarely presents with neurologic symptoms. Although the definitions, classifications, and methods of diagnosis of this spinal deformity have been established and accepted, the ideal surgical management of this deformity remains highly debated. Fusion in situ techniques are often technically easier to perform and provide lower risk of neurologic complications, whereas reduction and fusion techniques offer greater restoration of global spino-pelvic balance. Preoperative spino-pelvic parameters may have utility in assisting in procedural selection; however, future, higher-quality and longer-term studies are warranted to determine the optimal surgical intervention among the widely available techniques currently used, and to better define the indications for these interventions.

Etiology-Based Classification of Adjacent Segment Disease Following Lumbar Spine Fusion.

BACKGROUND: Adjacent segment disease (ASDz) is a potential complication following lumbar spinal fusion. A common nomenclature based on etiology and ASDz type does not exist and is needed to assist with clinical prognostication, decision making, and management. QUESTIONS/PURPOSES: The objective of this study was to develop an etiology-based classification system for ASDz following lumbar fusion. METHODS: We conducted a retrospective chart review of 65 consecutive patients who had undergone both a lumbar fusion performed by a single surgeon and a subsequent procedure for ASDz. We established an etiology-based classification system for lumbar ASDz with the following six categories: "degenerative" (degenerative disc disease or spondylosis), "neurologic" (disc herniation, stenosis), "instability" (spondylolisthesis, rotatory subluxation), "deformity" (scoliosis, kyphosis), "complex" (fracture, infection), or "combined." Based on this scheme, we determined the rate of ASDz in each etiologic category. RESULTS: Of the 65 patients, 27 (41.5%) underwent surgery for neurogenic claudication or radiculopathy for adjacent-level stenosis or disc herniation and were classified as "neurologic." Ten patients (15.4%) had progressive degenerative disc pathology at the adjacent level and were classified as "degenerative." Ten patients (15.4%) had spondylolisthesis or instability and were classified as "instability," and three patients (4.6%) required revision surgery for adjacent-level kyphosis or scoliosis and were classified as "deformity." Fifteen patients (23.1%) had multiple diagnoses that included a combination of categories and were classified as "combined." CONCLUSION: This is the first study to propose an etiology-based classification scheme of ASDz following lumbar spine fusion. This simple classification system may allow for the grouping and standardization of patients with similar pathologies and thus for more specific pre-operative diagnoses, personalized treatments, and improved outcome analyses.

Do Clinical Outcomes and Sagittal Parameters Differ Between Diabetics and Nondiabetics for Degenerative Spondylolisthesis Undergoing Lumbar Fusion?

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To assess the effect of diabetes mellitus (DM) on clinical and radiographic outcomes in patient with degenerative spondylolisthesis undergoing posterior lumbar spinal fusion. METHODS: Analysis of patients who underwent open posterior lumbar spinal fusion from 2011 to 2018. Patients being medically treated for DM were identified and separated from nondiabetic patients. Visual analogue scale Back/Leg pain and Oswestry Disability Index (ODI) were collected, and achievement of minimal clinically important difference was evaluated. Lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), and PI-LL difference were measured on radiographs. Rates of postoperative complications were also collected. RESULTS: A total of 850 patients were included; 78 (9.20%) diabetic patients and 772 (90.80%) nondiabetic patients. Final PI-LL difference was significantly larger (P = .032) for patients with diabetes compared to no diabetes, but there were no other significant differences between radiographic measurements, operative time, or postoperative length of stay. There were no differences in clinical outcomes between the 2 groups. Diabetic patients were found to have a higher rate of discharge to a facility following surgery (P = .018). No differences were observed in reoperation or postoperative complication. CONCLUSIONS: While diabetic patients had more associated comorbidities compared with nondiabetic patients, they had similar patient-reported and radiographic outcomes. Similarly, there are no differences in rates of reoperation or postoperative complications. This study indicates that diabetic patients who have undergone thorough preoperative screening of related comorbidities and appropriate selection should be considered for lumbar spinal fusion.

Sagittal Balance in Adult Idiopathic Scoliosis.

STUDY DESIGN: A narrative review article study. OBJECTIVE: The objective of this study was to highlight guiding principles and challenges faced with addressing sagittal alignment in patients with adult idiopathic scoliosis (AIS) and to discuss effective surgical strategies based upon our clinical experience. SUMMARY OF BACKGROUND DATA: Previous research and guidelines for the treatment of AIS have focused on the correction of spinal deformity in the coronal and axial planes. Failure to address sagittal deformity has been associated with numerous adverse clinical outcomes. METHODS: This is a review of the current body of literature and a description of the rod derotation surgical technique for correction in the sagittal plane. RESULTS: Several studies have offered general goals for postoperative radiographic measures in the sagittal plane for patients with AIS. However, these guidelines are evolving as diagnostic and therapeutic modalities continue to improve. The rod derotation surgical technique through differential metal rods is one method to potentially address sagittal balance in AIS. CONCLUSIONS: Alignment in the sagittal plane is a unique challenge facing surgeons for patients with AIS. Further research with an assessment of functional outcomes and longer follow-up is needed to more precisely guide treatment principles. LEVEL OF EVIDENCE: Level IV.

Does obesity impact lumbar sagittal alignment and clinical outcomes after a posterior lumbar spine fusion?

PURPOSE: The purpose of this study is to compare clinical patient-reported outcomes and radiographic sagittal parameters between obese and non-obese patients following open posterior lumbar spine fusion (PLSF). METHODS: A retrospective cohort study was conducted for patients who underwent open PLSF from 2011 to 2018. Patients were classified as obese as per Center for Disease Control and Prevention guidelines if their body mass index (BMI) ≥ 30 kg/m2. Preoperative and final visual analog scale (VAS) back pain, VAS leg pain, and Oswestry Disability Index (ODI) were obtained for both obese and non-obese groups. Achievement of minimal clinically important difference was evaluated. Preoperative, immediate postoperative, and final lumbar plain radiographs were assessed to measure spinopelvic parameters. Additionally, postoperative complication measures were collected. RESULTS: A total of 569 patients were included; 290 (50.97%) patients with BMI < 30 (non-obese) and 279 (49.03%) patients with BMI ≥ 30 (obese). Patients classified as obese were more likely to have a diagnosis of diabetes mellitus (p < 0.001), and American Society of Anesthesiologists Physical Status Classification System of ≥ 3 (p < 0.001). Obese patients had significantly longer operative times (p < 0.001) compared to non-obese patients. There was no difference in radiographic measurements, patient-reported outcomes, postoperative complications, or reoperations between groups. CONCLUSION: Obese patients had significantly more comorbidities and longer operative time compared to non-obese patients. However, sagittal parameters, patient-reported outcomes, inpatient complications, length of hospital stay, and reoperations were similar between groups. Given these findings, open PLSF can be considered safe and effective in obese patients after thorough consideration of related comorbidities. These slides can be retrieved under Electronic Supplementary Material.

Does increasing age impact clinical and radiographic outcomes following lumbar spinal fusion?

BACKGROUND CONTEXT: Despite the growing senior population within the United States, there is a lack of consensus regarding the safety and efficacy of performing lumbar spinal fusion for this population. PURPOSE: To evaluate the clinical and radiographic outcomes in different age cohorts following lumbar spinal fusion. STUDY DESIGN: Retrospective cohort analysis. PATIENT SAMPLE: Analysis of 1,184 patients who underwent posterolateral lumbar fusion from 2011 to 2018. Surgery was indicated after failure of conservative treatment to address radiculopathy and/or neurogenic claudication. Patients were excluded if they were under 18 years of age at the time of surgery, had a lumbar fracture, tumor, or infection, or had fusions involving the thoracic spine, high-grade spondylolisthesis, or concomitant deformity. Of the 1,184 patients, 850 patients were included. Patients were divided into three roughly equal groups for analysis: young (18-54 years), middle-aged (55-69 years), and senior (≥70 years). OUTCOME MEASURES: Visual Analog Scale Back/Leg pain, and Oswestry Disability Index (ODI) were collected, and achievement of minimal clinically important difference was evaluated. Lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), and PI-LL difference were measured on radiographs. Rates of postoperative complications were analyzed. METHODS: Several radiographic parameters were measured using plain radiographs obtained at preoperative, immediately postoperative (standing radiographs performed on postoperative day 1), and most recent follow-up visits. Preoperative and final patient-reported outcomes, along with demographic information, were obtained all patients. Binary outcome variables were compared between groups with multivariate logistic regression, and continuous outcome variables were compared using multivariate linear regression, with age 18 to 54 years used as the reference. Multivariate regressions were used to compare outcomes between cohorts while controlling baseline characteristics. RESULTS: A total of 850 patients were included; 330 young (38.80%), 317 middle-aged (37.30%), and 203 senior (23.90%). Seniors had higher postoperative length of stay compared to younger patients (p<.001). Younger patients had worse final ODI scores compared to middle-aged patients (p=.002). Seniors had higher rates of proximal ASD (p=.002) compared to young patients. There was no difference in achievement of minimal clinically important differences (MCID) between all three groups. CONCLUSIONS: Senior patients have significant improvement in patient-reported clinical outcomes, despite having greater comorbidities, and longer length of stay. However, given a general lack of achievement of MCID across all cohorts, these findings suggest the need for a critical re-evaluation of the role of lumbar spinal fusion in the management of patients with refractory radiculopathic and/or neurogenic claudication symptoms.

Patients with predominantly back pain at the time of lumbar fusion for low-grade spondylolisthesis experience similar clinical improvement to patients with predominantly leg pain: mid-term results.

BACKGROUND CONTEXT: Patients with back pain predominance (BPP) have traditionally been thought to derive less predictable symptomatic relief from lumbar fusion surgery. PURPOSE: To compare postoperative clinical outcomes as well as degree of improvement in clinical outcome measures between patients with BPP and patients with leg pain predominance (LPP) undergoing open posterior lumbar fusion. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: Analysis of patients who underwent an open posterior lumbar fusion for low-grade (Meyerding Grade I or II) degenerative or isthmic spondylolisthesis from 2011 to 2018 was conducted. Surgery was indicated after failure of conservative treatment to address radiculopathy and/or neurogenic claudication. Patients were excluded if they were under 18 years of age at the time of surgery, had less than 6 months of follow-up, presented with a lumbar vertebral body fracture, tumor, or infection, or underwent a fusion surgery that extended to the thoracic spine, high-grade spondylolisthesis, or concomitant deformity. OUTCOME MEASURES: Radiographs obtained at preoperative, immediate postoperative, and final visits were evaluated for presence or absence of fusion. Patient-reported outcomes were recorded at preoperative and final clinic visits that included: visual analog scale (VAS) back/leg pain, and Oswestry disability index (ODI). Achievement of minimal clinically important difference (MCID) was analyzed, along with rates of postoperative complication and reoperation. METHODS: Preoperative and final patient-reported outcomes were obtained. Achievement of MCID was evaluated using following thresholds: ODI 14.9, VAS-back pain 2.1, VAS-leg pain 2.8. For analysis, patients were divided into two groups based on predominant location of pain: predominantly VAS-back pain (BPP) and predominantly VAS-leg pain (LPP). RESULTS: One hundred forty-one patients met inclusion criteria. Of these, 71 had LPP, and 70 had BPP. Patients with preoperative LPP experienced greater improvements in VAS-leg (p<.001) compared to those with BPP, whereas patients with preoperative BPP experienced greater improvements in VAS-back (p=.011) postoperatively compared to those with LPP. There were no differences in the final clinical outcomes. Additionally, LPP achieved MCID for VAS-leg (p=.027) at significantly higher proportion than BPP and BPP achieved MCID for VAS-back (p=.050) at significantly higher proportion than LPP. CONCLUSIONS: Patients with low-grade spondylolisthesis who underwent an open posterior lumbar fusion had improvement in symptoms regardless of presentation with BPP or LPP. In properly indicated patients, posterior spinal fusion is effective for those with BPP in the setting of experiencing both leg and back pain, and clinicians can use this information for perioperative discussions and surgical decision-making.

Comparison of Stand-alone Lateral Lumbar Interbody Fusion Versus Open Laminectomy and Posterolateral Instrumented Fusion in the Treatment of Adjacent Segment Disease Following Previous Lumbar Fusion Surgery.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim of this study was to compare clinical and radiographic outcomes of patients who underwent stand-alone lateral lumbar interbody fusion (LLIF) to those who underwent posterolateral fusion (PLF) for symptomatic adjacent segment disease (ASD). SUMMARY OF BACKGROUND DATA: Recent studies have suggested that LLIF can successfully treat ASD; however, there are no studies to date that compare LLIF with the traditional open PLF in this cohort. METHODS: A total of 47 consecutive patients who underwent LLIF or PLF for symptomatic ASD between January 2007 and August 2016 after failure of conservative management were reviewed for this study. Patient-reported outcomes (PROs) were collected on all patients at preoperative, postoperative, and most recent post-operative visit using the Oswestry Disability Index, Visual Analog Scale (VAS)-Back, and VAS-Leg surveys. Preoperative, immediate postoperative, and most recent postoperative radiographs were assessed for pelvic incidence, fusion, intervertebral disc height, segmental and overall lumbar lordosis (LL). Symptomatic ASD was diagnosed if back pain, neurogenic claudication, or lower extremity radiculopathy presented following a previous lumbar fusion. Preoperative plain radiographs were evaluated for evidence of adjacent segment degeneration. RESULTS: A total of 47 patients (23 LLIF, 24 PLF) met inclusion criteria. Operative times (P < 0.001) and intraoperative blood loss (P < 0.001) were significantly higher in the PLF group. Patients who underwent PLF were discharged approximately 3 days after the LLIF patients (P < 0.001). PROs in the PLF and LLIF cohorts showed significant and equivalent improvement, with equivalent radiographic fusion rates. LLIF significantly improve segmental lordosis (P < 0.001), total LL (P = 0.003), and disc height (P < 0.001) from preoperative to immediate postoperative and final follow-up (P = 0.004, P = 0.019, P ≤ 0.001, respectively). CONCLUSION: Although LLIF may provide less perioperative morbidity and shorter length of hospitalization, both techniques are safe and effective approaches to restore radiographic alignment and provide successful clinical outcomes in patients with adjacent segment degeneration following previous lumbar fusion surgery. LEVEL OF EVIDENCE: 3.

Clinical Presentation and Outcomes of Patients With a Lumbar Far Lateral Herniated Nucleus Pulposus as Compared to Those With a Central or Paracentral Herniation.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: Examine pre- and postoperative outcomes between patients presenting with a central/paracentral versus a far lateral herniated nucleus pulposus (HNP) and assess whether significantly worse postoperative outcomes, assessed via patient self-reported survey, are associated with far lateral disc herniations. METHODS: We performed a retrospective cohort analysis of patients who underwent primary lumbar decompression between January 2008 and December 2015. Groups were divided based on herniation type, central/paracentral or far lateral. Patients with 3 months, or longer, of follow-up were included. Variables analyzed included demographics, American Society of Anesthesiologists (ASA) Score, Charleston Comorbidity Index (CCI), Oswestry Disability Index (ODI) scores, Visual Analog Scales (VAS) scores for the back and leg, 12-Item Short Form Mental and Physical Survey (SF-12) scores, and Veterans RAND 12-Item Mental and Physical Survey (VR-12) scores. RESULTS: A total of 100 patients met the inclusion criteria. Postoperative ODI scores for central/paracentral HNP were significantly lower compared to far lateral HNP. Patients with a far lateral disc herniation presented with significantly lower preoperative SF-12 and VR-12 scores. The improvement in ODI score from preoperative to final was significantly lower in the patients presenting with a far lateral HNP. CONCLUSIONS: Although patients with far lateral HNP present with worse preoperative outcome scores, they can expect similar symptom improvement to central or paracentral herniations following discectomy. This information can be used for future surgeons when weighing conservative versus surgical treatment of far lateral herniations.

All-posterior total en bloc spondylectomy for thoracic spinal tumors.

Total en bloc spondylectomy (TES) involves disruption of the bony neural ring via bilateral pediculotomy and posterior en bloc laminectomy followed by the en bloc vertebrectomy. All-posterior TES allows for resection of malignant and benign aggressive spine tumors with minimal morbidity. The purpose of this report is to describe two cases of all-posterior spondylectomy using the recently developed Resegone retractor (K2M, Leesburg, VA, USA) which facilitates an all-posterior resection. The technique is well described and generally includes 3 major portions: a resection of the posterior elements with bilateral costotransversectomy, passage of threadwire saws anterior to the vertebral bodies, and en bloc resection of the anterior column. With the device in place, the sawing of the bone can be performed without risking pull-through into the cord, while cutting through the desired path in a smooth and parallel fashion.

Comparing Allografts to Autografts for Maintenance of Cervical Sagittal Parameters and Clinical Outcomes Following Anterior Cervical Discectomy and Fusion With Anterior Cervical Plating.

OBJECTIVE: Current literature has not shown if using either allograft or autograft differentially affects postoperative cervical sagittal parameters. The goal of this study was to compare sagittal alignment and patient-reported outcomes following anterior cervical discectomy and fusion (ACDF) with allograft versus autograft. METHODS: A retrospective cohort analysis of patients who underwent single-level ACDF was conducted. Preoperative, immediate postoperative, and final follow-up radiographic assessments were conducted and included: change in C2-7 lordosis, T1 slope, levels fused, sagittal vertical axis (SVA), fusion mass lordosis, and proximal and distal adjacent segment degeneration (ASD). Patient-reported outcomes were obtained using the Neck Disability Index and visual analogue scale scores for neck and arm. RESULTS: A total of 404 patients were assessed; 353 using allograft and 51 using autograft. No significant differences existed in demographics. Cervical lordosis improved in both groups without significant changes in SVA. Autograft group had a significantly greater amount of lordosis at the proximal segment on immediate postoperative radiographs and less overall cervical lordosis at final follow-up. Sagittal parameters were similar at each time point without significant changes between the 3-time points. No significant differences existed in radiographic ASD or reoperation rates. Fusion rates exceeded 96% in both groups. No significant differences existed between preoperative, postoperative, or change in patient-reported outcomes between the 2 groups. CONCLUSION: Sagittal alignment is maintained following ACDF when using either allograft or autograft. Radiographic evidence of ASD is present in both groups; however, this was not considered clinically significant, given low rates of pseudarthrosis or reoperation. No significant differences exist between groups in terms of patient-reported outcomes.

Gender Differences for Hip and Knee Arthroplasty: Complications and Healthcare Utilization.

INTRODUCTION: The influence of patient gender on complications and healthcare utilization remains unexplored. The purpose of the present study was to determine if patient gender significantly affected outcomes following total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS: Retrospective cohort study of THA and TKA patients was performed using the Nationwide Inpatient Sample from 2002 to 2011. Only patients who underwent elective procedures and those with complete perioperative data were included. Multivariate logistic regression was used to compare the rates of adverse events between male and female cohorts while controlling for baseline characteristics. RESULTS: A total of 6,123,637 patients were included in the study (31.2% THA and 68.8% TKA). The cohort was 61.1% female. While males had a lower rate of any adverse event (odds ratio [OR] = 0.8, P < .001), urinary tract infection (OR = 0.4, P < .001), deep vein thrombosis/pulmonary embolism (OR = 0.9, P < .001), and blood transfusion (OR = 0.5, P < .001), male gender was associated with statistically significant increases in the rates of death (OR = 1.6, P < .001), acute kidney injury (OR = 1.6, P < .001), cardiac arrest (OR = 1.7, P < .001), myocardial infarction (OR = 1.6, P < .001), pneumonia (OR = 1.1, P < .001), sepsis (OR = 1.6, P < .001), surgical site infection (OR = 1.4, P < .001), and wound dehiscence (OR = 1.4, P < .001). CONCLUSION: Males had increased rates of many individual adverse events. Females had higher rates of urinary tract infection, which translated to an overall higher rate of adverse events in females because of the rarity of the other individual adverse events.

Obesity does not impact clinical outcome but affects cervical sagittal alignment and adjacent segment degeneration in short term follow-up after an anterior cervical decompression and fusion.

BACKGROUND CONTEXT: Obesity increases complications and cost following spine surgery. However, the impact on sagittal alignment and adjacent segment degeneration (ASD) after anterior cervical decompression and fusion is less understood. PURPOSE: To compare clinical and radiographic outcomes after anterior cervical decompression and fusion between obese and nonobese patients. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: In all, 467 patients that underwent an anterior cervical decompression and fusion procedure from January 2008 through December 2015 were assessed. Surgery indications were radiculopathy, myelopathy, or myeloradiculopathy that had failed nonoperative treatments. Exclusion criteria included patients who had postoperative follow-up less than 6 months. Of 467 patients originally identified, 399 fulfilled the inclusion and exclusion criteria. OUTCOME MEASURES: The following patient-reported outcomes were obtained: Neck Disability Index and Visual Analog Scale scores for the neck and arm pain. Radiographic assessments included: C2-C7 lordosis, T1 angle, levels fused, sagittal vertical axis (SVA), fusion mass lordosis, proximal and distal adjacent segment lordosis, ASD, and presence of fusion. METHODS: Plain radiographs were performed preoperatively, immediately postoperatively, and final follow-up. Demographic information was collected on all patients. Baseline patient characteristics were compared using chi-squared analysis and independent sample t tests for categorical and continuous data, respectively. For analysis, patients were divided into 4 groups based on obesity stratification as defined by Center for Disease Control: body mass index (BMI) <25 kg/m2 (normal weight), BMI≥25 kg/m2 to <30 kg/m2 (overweight), ≥30 kg/m2 to <35 kg/m2 (Class I obesity), BMI≥35 kg/m2 to <40 kg/m2 (Class II obesity), and BMI≥40 kg/m2 (Class III obesity). Additionally, obese (≥30 kg/m2) and nonobese (<30 kg/m2) patients were compared in a separate analysis. Multivariate analysis was used to compare clinical and radiographic outcomes among all BMI classes, as well as between BMI≥30 kg/m2 versus BMI<30 kg/m2 study groups. Multivariate analyses controlled for differences in baseline patient characteristics and included age, sex, smoking, American Society of Anesthesiologists Physical Status Score, diabetes mellitus, and number of levels. RESULTS: Of the 399 patients assessed, 97 were identified as normal weight, 157 as overweight, 81 with Class I obesity, 45 with Class II obesity, and 19 with Class III obesity. On multivariate analysis, despite having similar SVA measurements on preoperative radiographs, increase in BMI was associated with increase in postoperative SVA (p=0.041) along with significantly larger SVA in immediate postoperative (p=0.004) and final follow-up radiographs (p=0.003) for patients with BMI≥30 kg/m2 versus BMI<30 kg/m2. Furthermore, patients with BMI≥30 kg/m2 had smaller preoperative (p=0.012), immediate postoperative (p=0.017), and final lordosis (p<0.001) in addition to smaller immediate postoperative (p=0.025) and final fusion segment lordosis (p=0.015) and smaller preoperative (p=0.024) and final distal lordosis (p=0.021) compared with patients with BMI<30 kg/m2. Additionally, greater BMI was associated with lower final Visual Analog Scale neck scores (p=0.008). Radiographic early ASD rates were higher in patients BMI≥30 kg/m2 versus BMI<30 kg/m2 (p=0.028). CONCLUSIONS: Overall, obese patients who underwent anterior cervical decompression and fusion had similar patient-reported outcomes compared with nonobese patients but had worse radiographic parameters and higher rates of ASD development compared with nonobese patients. This underscores the importance of patient selection and surgical approach for both patient populations.

Patients Undergoing Revision Microdiskectomy for Recurrent Lumbar Disk Herniation Experience Worse Clinical Outcomes and More Revision Surgeries Compared With Patients Undergoing a Primary Microdiskectomy.

INTRODUCTION: Recurrent disk herniation treatment aims to optimize outcomes. This study compares the demographics and patient-reported outcomes of patients who underwent primary or revision lumbar microdiskectomy surgery for recurrent disk herniation. METHODS: A retrospective cohort analysis was performed of consecutive patients who underwent primary or revision lumbar microdiskectomies between January 2008 and December 2015. Patients were divided into two groups: primary (primary) and revision (recurrent). Herniated disks were confirmed preoperatively using MRI. Patient-reported outcomes included Visual Analog Scales (VAS) scores for the back and leg, Oswestry Disability Index scores, 12-Item Short Form Mental and Physical Survey scores, and the Veterans RAND 12-Item Health Mental and Physical Survey scores. RESULTS: One hundred ten patients met inclusion criteria: 72 from primary cohort and 38 from recurrent cohort. Recurrent patients experienced presurgical symptoms for significantly less time. On bivariate analysis, recurrent patients reported significantly worse preoperative VAS-back and VAS-leg scores. On multivariate analysis, recurrent patients reported significantly worse postoperative VAS-back, VAS-leg, and Oswestry Disability Index scores. Recurrent patients were less likely to be satisfied with surgical outcomes and to feel that surgery had met or exceeded their expectations. CONCLUSION: Patients undergoing revision microdiskectomy are likely to experience worse postoperative symptoms and disability relative to patients undergoing primary microdiskectomy.

The Duration of Symptoms Does Not Impact Clinical Outcomes Following Lumbar Decompression Surgery.

STUDY DESIGN: A retrospective cohort analysis. OBJECTIVE: The aim of this study was to assess whether duration of symptoms (DOS) has an effect on clinical outcomes in patients undergoing lumbar decompression. SUMMARY OF BACKGROUND DATA: The success of surgical interventions for lumbar spinal stenosis varies depending on numerous factors, including DOS. However, existing literature does not provide a clear indication of the outcome of lumbar decompression surgery in regard to DOS secondary to nerve root compression. METHODS: Analysis of patients who underwent primary lumbar laminectomy from 2008 through 2015 by one of two senior orthopedic spine surgeons was conducted. Exclusion criteria were as follows: previous lumbar surgery, patient under 18 years of age at time of surgery, or postoperative follow-up less than 3 months. Patients were divided into groups on the basis of preoperative DOS: less than 1 year and 1 year or greater. Patient-reported outcomes were obtained using Oswestry Disability Index (ODI) scores, Visual Analog Scales (VAS) scores for the back and leg, 12-Item Short Form Mental and Physical Survey (SF-12) scores, and Veterans Rand 12-Item Health Mental and Physical Survey (VR-12) scores. Patients were surveyed about expectations and postoperative satisfaction. RESULTS: Two hundred ten patients were assessed; 108 with DOS of less than 1 year and 102 with DOS of 1 year or more. On multivariate analysis, patients with DOS of 1 year or greater presented with significantly lower SF-12 scores (P = 0.043). No significant differences existed in other outcome survey scores. Reoperation rates were not significantly different (P = 0.904). Both groups reported high levels of satisfaction (odds ratio 0.42, P = 0.483) and that surgery met or exceeded their expectations (odds ratio 1.00, P = 0.308). CONCLUSION: Symptom chronicity did not significantly affect postoperative clinical outcomes, reoperation rates, or patient satisfaction. Nonoperative treatment of lumbar spinal stenosis is often successful but may delay operative intervention. However, results of this study suggest that the delay does not negatively impact surgical outcomes. LEVEL OF EVIDENCE: 3.

Intraoperative CT and Surgical Navigation for Iliosacral Screws: Technique for Patients With Sacral Dysmorphism.

Percutaneous iliosacral screw (IS) fixation for pelvic ring injuries with the use of an O-arm imaging system has been associated with decreased procedure time and improved accuracy of IS screw placement compared with the use of fluoroscopic guidance. Specifically, patients with sacral dysmorphism require identification of safe bony sacral corridors, using specific anatomical measurements, to decrease the likelihood of complications such as screw perforation. Intraoperative computed tomography imaging and navigation can aid in safe and accurate IS screw fixation in patients with difficult anatomy.

Multi- versus single-level anterior cervical discectomy and fusion: comparing sagittal alignment, early adjacent segment degeneration, and clinical outcomes.

PURPOSE: The purpose of this study was to compare the rates of adjacent segment degeneration (ASD), sagittal alignment parameters, and patient-reported outcomes in patients who underwent multi-level versus single-level anterior cervical discectomy and fusion (ACDF). METHODS: A retrospective cohort analysis was performed on consecutive patients who underwent an ACDF. Pre- and post-operative radiographic assessment included ASD, change in C2-C7 lordosis, T1 angle, levels fused, sagittal vertical axis (SVA), fusion mass lordosis, proximal and distal adjacent segment lordosis. Patient-reported outcomes were obtained. RESULTS: Of the 404 that underwent an ACDF with a minimum of 6 months of follow-up (average 28 months), there was no significant difference in the rate of radiographic ASD overall (p = 0.479) or in the proximal or distal adjacent segments on multivariate analysis. Secondarily, the multi-level fusions appear to restore significantly greater amounts of lordosis compared to single-level procedures (p < 0.001) and are able to maintain the corrected cervical lordosis and fusion segment lordosis over time. From the immediate post-operative period to final follow-up, the single-level ACDFs show continuing lordosis improvement (p = 0.005) that is significantly greater than that of the multi-level constructs. There were no significant differences between pre-operative, post-operative, or change in patient-reported outcomes. CONCLUSIONS: Two years following an ACDF, patients who underwent multi-level fusions appear to restore significantly greater amounts of lordosis compared to single-level procedures, while single-level ACDFs show significantly greater amounts of lordosis improvement over time. Multi-level procedures may not be at a significantly greater risk of developing early radiographic evidence of ASD compared to single-level procedure. These slides can be retrieved under Electronic Supplementary Material.

Sagittal spinopelvic malalignment in degenerative scoliosis patients: isolated correction of symptomatic levels and clinical decision-making.

BACKGROUND: This study aims to determine if (1) loss of lumbar lordosis (LL), often associated with degenerative scoliosis (DS), is structural or rather largely due to positional factors secondary to spinal stenosis; (2) only addressing the symptomatic levels with a decompression and posterolateral fusion in carefully selected patients will result in improvement of sagittal malalignment; and (3) degree of sagittal plane correction achieved with such a local fusion could be predicted by routine pre-operative imaging. METHODS: A retrospective study design with prospectively collected imaging data of a consecutive series of surgically treated DS patients who underwent decompression and instrumented fusion at only symptomatic levels was performed. Pre- and post-operative plain radiographs and pre-operative magnetic resonance imaging (MRIs) of the spinopelvic region were analyzed. LL, pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS) were assessed in all patients. As a requirement for the surgical strategy, all patients presented with a pre-operative PI-LL mismatch greater than 10°. Post-operative complications were assessed. RESULTS: Pre-operative MRIs and lumbar extension radiographs revealed a mean LL of 42° (range 10-66°) and 48° (range 20-74°), respectively, in 68 patients (mean follow-up 29 months). LL post-operatively was corrected to a mean PI-LL of 10°. Of patients who achieved PI-LL mismatch within 10o on their pre-operative extension lateral lumbar radiographs, 62.5% were able to maintain a PI-LL mismatch within 10° on their initial post-operative films. Only 37.5% were not able to achieve that mismatch on extension radiographs (p = 0.001, OR = 9.58). Similarly, 54.2% were able to achieve a PI-LL < 10° on initial post-operative radiographs, when pre-operative MRI revealed a PI-LL mismatch within 10°. In contrast, only 20.5% achieved that goal post-operatively if their mismatch was greater than 10o on their MRI (p = 0.003, OR = 4.25). CONCLUSION: With a decompression and instrumented fusion of only the symptomatic levels in symptomatic DS patients, we were able to achieve a PI-LL mismatch to within 10°. The loss of LL observed pre-operatively may be largely positional rather than structural. The amount of LL correction observed immediately after surgery can be predicted from pre-operative lumbar extension radiographs and supine sagittal MRI.

Relationship of Sacral Fractures to Nerve Injury: Is the Denis Classification Still Accurate?

OBJECTIVE: Use modern computed tomographic imaging to reassess neurological injury risks associated with zone I-III sacral fractures as originally described by Denis et al. DESIGN: Retrospective case-control study. SETTING: University Level I Trauma Center. PATIENTS/PARTICIPANTS: One thousand five hundred seven consecutive patients who presented with sacral fractures between January 2000 and August 2012. MAIN OUTCOME MEASUREMENTS: Patients were stratified based on the diagnosis of acute neurological injury. The risk of severe and complex sacral fractures based on the presence of nerve injury was assessed. RESULTS: The rate of nerve injury was significantly lower compared with historic data (3.5% vs. 21.6%, P < 0.001). Acute nerve injury was a significant risk factor for displaced (odds ratio [OR]: 8.4, 95% confidence interval [CI], 1.4-51.9) and comminuted (OR: 5.2, 95% CI, 1.7-16.3) sacral fractures as well as zone II (OR: 3.4, 95% CI, 1.1-10.1) and III (OR: 3.9, 95% CI, 1.0-16.4) fractures. CONCLUSIONS: The incidence of nerve injuries associated with sacral fractures is significantly lower than originally published by Denis et al. Patients with a nerve injury were highly correlated with having a displaced, comminuted, or zone III fracture, or spinopelvic dissociation; the authors recommend a fine cut computerized tomography for further investigation if these findings are not apparent on initial radiographic imaging. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.