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Background Context: Lumbar decompression and lumbar fusion are effective methods of treating spinal compressive pathologies refractory to conservative management. These surgeries are typically used to treat different spinal problems, but there is a growing body of literature investigating the outcomes of either approach for patients with lumbar degenerative spondylolisthesis and stenosis. Different operations are associated with different risks and different potential needs for reoperation. Patient acceptance of reoperation rates after spinal surgery is currently not well understood., Purpose: The purpose of this study is to identify patient tolerance for reoperation rates following lumbar decompression and lumbar fusion surgery., Design: A qualitative and quantitative survey intended to capture information on patient preferences was administered., Patient Sample: Written informed consent was obtained from patients presenting to 2 spinal clinics., Outcome Measures: Patients were asked their threshold tolerance for reoperation rates in the context of choosing a smaller (decompression) versus larger (fusion) spinal surgery., Methods: A survey was administered to patients at 2 spinal clinics-1 surgical and 1 nonsurgical. A consecutive series of new patients over multiple clinic days who agreed to participate in the study and filled out the survey are reported on here. Patients were asked to assess, contemplating a problem that could either be treated with lumbar decompression or lumbar fusion, the level at which 1) the likelihood that needing a repeat surgery within 3 to 5 years would change their mind about choosing the decompression operation and cause them to choose the fusion operation and then 2) the likelihood of needing a repeat surgery within 3 to 5 years that would be acceptable to them after the fusion operation. The distribution of patient responses was assessed with histograms and descriptive statistics., Results: Ninety patients were surveyed, and of these, 73 patients (81.1%) returned fully completed questionnaires. The median reoperation acceptance rates after a decompression was <60%, while the median acceptable revision rate when contemplating the fusion surgery was 10%., Conclusions: Patient acceptance for the potential need for revision surgery is higher when considering a decompression compared to a fusion operation. Reoperation risk rates along with the magnitude of the surgical intervention are important considerations in determining patients' surgical preferences. Understanding patient preferences and risk tolerances can aid clinicians in shared decision-making, potentially improving patient satisfaction and outcomes in the several lumbar pathologies which can be ameliorated with either decompression or fusion., Competing Interests: Declaration of Competing Interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Patients undergoing lumbar spine surgery have high rates of preoperative opioid use, which is associated with inferior outcomes and higher risks for opioid dependency postoperatively., Purpose: Determine whether there are identifiable subgroups of patients that follow distinct patterns in pre- and postoperative opioid dosing. Examine how preoperative patterns in opioid dosing relate to postoperative opioid patterns, opioid cessation, and the risk for adverse events., Study Design/setting: Retrospective analysis of an administrative claims database (Meritive TM Marketscan® Research Databases 2007-2015)., Patient Sample: The 9,768 patients undergoing primary single level lumbar fusion., Outcome Measures: Primary: daily morphine milligram equivalent (MME) opioid dosing calculated from prescriptions dispensed for 1 year before and after surgery; secondary: 90-day all-cause readmission and complications, 90-day acute postoperative pain, 90-day and 1-year reoperation, surgical costs, length of stay, and discharge disposition., Methods: Distinct patient subgroups defined by patterns of daily MME pre- and postoperatively were identified via group-based trajectory modeling. Associations between these groups and outcomes were assessed with multivariable logistic regression with risk adjustment for patient and surgical factors., Results: Among primary single level lumbar fusion patients, 59.5% filled an opioid prescription in the 3 months preceding surgery, whereas 40.5% were opioid naïve (Naïve). Five distinct subgroups of daily MME were identified among those filling opioids preoperatively: (1) Naïve to 3m (21.2% of patients): no opioids until 3 months preoperatively, escalating to 15 MME/day; (2) Low to 3m (11.4%): very low or as needed dose until 3 months preoperatively, escalating to 15 MME/day; (3) 6m Rise (6.9%): no opioids until 6 months preoperatively, escalating to >30 MME/day; (4) Medium (9.8%): increased linearly from 10 to 25 MME/day across the year before surgery; (5) High (10.0%): increased linearly from 60 to >80 MME/day across the year before surgery. These five preoperative opioid groups were related to postoperative opioids filled in a dose-response manner. The two preoperative patient groups with chronic Medium to High-dose opioid dosing were associated with increased adverse events, including all-cause readmission, reoperation, and pneumonia, whereas a low baseline group with a large, earlier preoperative rise in opioid dosing (6m Rise) had increased encounters for acute postoperative pain. Postoperatively, only 9.5% of patients did not fill an opioid prescription. Five distinct postoperative subgroups were identified based on their patterns in daily MME: Two groups ceased filling opioids within the year following surgery (33.6% of patients), and three groups declined in opioid dosage following surgery but plateaued at low (0-5 MME/day, 29.1%), medium (10-15 MME/day, 12.0%), or high (70-75 MME/day), 13.1%) doses by 1 year. Patients within the higher preoperative opioid groups were more likely to belong to the postoperative groups that were unable to cease filling opioids., Conclusions: Identification of a patient's preoperative time trend in daily opioid use may provide significant prognostic value and help guide pain management and risk reduction efforts., Level of Evidence: III., Competing Interests: Funding disclosure statement No financial support was procured for this study., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Proximal junctional kyphosis (PJK) is a complication following surgery for adult spinal deformity (ASD) possibly ameliorated by polymethyl methacrylate (PMMA) vertebroplasty of the upper instrumented vertebrae (UIV). This study quantifies PJK following surgical correction bridging the thoracolumbar junction ± PMMA vertebroplasty., Methods: ASD patients from 2013 to 2020 were retrospectively reviewed and included with immediate postoperative radiographs and at least one follow-up radiograph. PMMA vertebroplasty at the UIV and UIV + 1 was performed at the surgeons' discretion., Results: Of 102 patients, 56% received PMMA. PMMA patients were older (70 ± 8 vs. 66 ± 10, p = 0.021), more often female (89.3% vs. 68.2%, p = 0.005), and had more osteoporosis (26.8% vs. 9.1%, p = 0.013). 55.4% of PMMA patients developed PJK compared to 38.6% of controls (p = 0.097), and the rate of PJK development was not different between groups in univariate survival models. There was no difference in PJF (p > 0.084). Reoperation rates were 7.1% in PMMA versus 11.4% in controls (p = 0.501). In multivariable models, PJK development was not associated with the use of PMMA vertebroplasty (HR 0.77, 95% CI 0.38-1.60, p = 0.470), either when considered overall in the cohort or specifically in those with poor bone quality. PJK was significantly predicted by poor bone quality irrespective of PMMA use (HR 3.81, p < 0.001)., Conclusions: In thoracolumbar fusions for adult spinal deformity, PMMA vertebroplasty was not associated with reduced PJK development, which was most highly associated with poor bone quality. Preoperative screening and management for osteoporosis is critical in achieving an optimal outcome for these complex operations., Level of Evidence: 4, retrospective non-randomized case review., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Understanding patient-specific trends in costs and healthcare resource utilization (HCRU) surrounding lumbar spine surgery is critically needed to better inform surgical decision making and the development of targeted interventions., Purpose: 1) Identify subgroups of patients following distinct patterns in direct healthcare payments pre- and postoperatively, 2) determine whether these patterns are associated with patient and surgical factors, and 3) examine whether preoperative payment patterns are related to postoperative payments, healthcare resource utilization (HCRU), and adverse events., Study Design/setting: Retrospective analysis of an administrative claims database (IBM Marketscan Research Databases 2007-2015)., Patient Sample: Adults undergoing primary single-level decompression surgery for lumbar stenosis (n=12,394)., Outcome Measures: Direct healthcare payments, HCRU payments (15 categories), 90-day complications and all-cause readmission, 2-year reoperation METHODS: Group-based trajectory modeling is an application of finite mixture modeling that is able to identify meaningful subgroups within a population that follow distinct developmental trajectories over time. We used this technique to identify subgroups of patients following distinct profiles in preoperative direct healthcare payments. A separate analysis was performed to identify distinct profiles in payments postoperatively. Patient and surgical factors associated with these payment profiles were assessed with multinomial logistic regression, and associations with adverse events were assessed with risk-adjusted multivariable logistic regression., Results: We identified 4 preoperative patient payment subgroups following distinct profiles in payments: Pre-Low (5.8% of patients), Pre-Early-Rising (4.8%), Pre-Medium (26.1%), and Pre-High (63.3%). Postoperatively, 3 patient subgroups were identified: Post-Low (8.9%), Post-Medium (29.6%), and Post-High (61.4%). Patients following the higher-cost pre- and postoperative payment profiles were older, more likely female, and had a greater physical and mental comorbidity burden. With each successively higher preoperative payment profile, patients were increasingly likely to have high postoperative payments, use more HCRU (particularly high-cost services such as inpatient admissions, ER, and SNF/IRF care), and experience postoperative adverse events. Following risk adjustment for patient and surgical factors, patients following the Pre-High payment profile had 209.5 (95% CI: 144.2, 309.7; p<.001) fold greater odds for following the Post-High payment profile, 1.8 (1.3, 2.5; p=.003) fold greater odds for 90-day complications, and 1.7 (1.2, 2.6; p=.035) fold greater odds for 2-year reoperation relative to patients following the Pre-Low payment profile., Conclusions: There are identifiable subgroups of patients who follow distinct profiles in direct healthcare payments surrounding lumbar decompression surgery. These payment profiles are related to patient age, sex, and physical and mental comorbidities. Notably, preoperative payment profiles may provide prognostic value, as they are associated with postoperative costs, HCRU, and adverse events., Level of Evidence: III., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background Context: Improved understanding of the pre- and postoperative trends in costs and healthcare resource utilization (HCRU) is needed to better inform patient expectations and aid in the development of strategies to minimize the significant healthcare burden associated with lumbar spine surgery., Purpose: Examine the time course of costs and HCRU in the 2 years preceding and following elective lumbar spine surgery for stenosis in a large national claims cohort., Study Design/setting: Retrospective analysis of an administrative claims database (IBM® Marketscan® Research Databases 2007-2015)., Patient Sample: Adult patients undergoing elective primary single-level lumbar surgery for stenosis with at least 2 years of continuous health plan enrollment pre- and postoperatively., Outcome Measures: Functional measures, including monthly rates of HCRU (15 categories), monthly gross covered payments (including payments made by the health plan and deductibles and coinsurance paid by the patient) overall, by HCRU category, and by spine versus non-spine-related., Methods: All available patients were utilized for analysis of HCRU. For analysis of payments, only patients on noncapitated health plans providing accurate financial information were analyzed. Payments were converted to 2015 United States dollars using the medical care component of the consumer price index. Trends in payments and HCRU were plotted on a monthly basis pre- and post-surgery and assessed with regression models. Relationships with demographics, surgical factors, and comorbidities were assessed with multivariable repeated measures generalized estimating equations., Results: Median monthly healthcare payments 2 years prior to surgery were $275 ($22, $868). Baseline HCRU at 2 years preoperatively was stable or only gradually rising (office visits, prescription drug use), but began an increasingly steep rise in many categories 6 to 12 months prior to surgery. Monthly payments began an increasingly steep rise 6 months prior to surgery, reaching a peak of $1,402 ($634, $2,827) in the month prior to surgery. This was driven by an increase in radiology, office visits, PT, injections, prescription medications, ER encounters, and inpatient admissions. Payments dropped dramatically immediately following surgery. Over the remainder of the 2 years, the median total payments declined only slightly, as a continued decline in spine-related payments was offset by gradually increased non-spine related payments as patients aged. By 2 years postoperatively, the percentage of patients using PT and injections returned to within 1% of the baseline levels observed 2 years preoperatively; however, spine-related prescription medication use remained elevated, as did other categories of HCRU (radiology, office visits, lab/diagnostic services, and also rare events such as inpatient admissions, ER encounters, and SNF/IRF). Patients with a fusion component to their surgeries had higher payments and HCRU preoperatively, and this did not resolve postoperatively. Variations in payments and HCRU were also evident among plan types, with patients on comprehensive medical plans-predominantly employer-sponsored supplemental Medicare coverage-utilizing more inpatient, ER, and inpatient rehabilitation & skilled nursing facilities. Patients on high-deductible plans had fewer payments and HCRU across all categories; however, we are unable to distinguish whether this is because they used fewer of these services or if they were paying for these services out of pocket without submitting to the payer. By 2 years postoperatively, 51% of patients had no spine-related monthly payments, while 33% had higher and 16% had lower monthly payments relative to 2 years preoperatively., Conclusions: This is the first study to characterize time trends in direct healthcare payments and HCRU over an extended period preceding and following spine surgery. Differences among plan types potentially highlight disparities in access to care and plan-related financial mediators of patients' healthcare resource utilization., Competing Interests: Declarations of Competing Interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Study Design: This was a retrospective comparative study., Objective: The objective of this study was to assess the effect of increased age on perioperative and postoperative complication rates, reoperation rates, and patient-reported pain and disability scores after lateral lumbar interbody fusion (LLIF)., Summary of Background Data: LLIF was developed to minimize soft tissue trauma and reduce the risk of vascular injury; however, there is little evidence regarding the effect of advanced age on outcomes of LLIF., Methods: Patients who underwent LLIF from 2009 to 2019 at one institution with a minimum 6-month follow-up were retrospectively reviewed. Patients less than 18 years old with musculoskeletal tumor or trauma were excluded. The primary outcome was the preoperative to postoperative change in the Numeric Pain Rating Scale (NPRS) for back pain. Operative time, estimated blood loss, length of stay, perioperative and 90-day complications, unplanned readmissions, reoperations, and change in Oswestry Disability Index were also evaluated. Relationships with age were assessed both with age as a continuous variable and segmenting by age below 70 versus 70+., Results: In total, 279 patients were included. The median age was 65±13 years and 159 (57%) were female. Age was not related to improvements in back NPRS and Oswestry Disability Index. Operative time, estimated blood loss, length of stay, perioperative and 90-day complications, unplanned readmissions, reoperations, and radiographic fusion rate also were not related to age. After multivariable risk adjustment, increasing age was associated with greater improvements in back NPRS. The decrease in back NPRS was 0.68 (95% confidence interval: 0.14, 1.22; P=0.014) points greater for every 10-year increase in age. Age was not associated with rates of complication, readmission, or reoperation., Conclusions: LLIF is a safe and effective procedure in the elderly population. Advanced age is associated with larger improvements in preoperative back pain. Surgeons should consider the benefits of LLIF and other minimally invasive techniques when evaluating elderly candidates for lumbar fusion., Level of Evidence: Level III., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: The study objectives were to use a large national claims data resource to examine rates of preoperative epidural steroid injections (ESI) in lumbar spine surgery and determine whether preoperative ESI or the timing of preoperative ESI is associated with rates of postoperative complications and reoperations., Methods: A retrospective longitudinal analysis of patients undergoing lumbar spine surgery for disc herniation and/or spinal stenosis was undertaken using the MarketScan® databases from 2007-2015. Propensity-score matched cohorts were constructed to compare rates of complications and reoperations in patients with and without preoperative ESI., Results: Within the year prior to surgery, 120,898 (46.4%) patients had a lumber ESI. The median time between ESI and surgery was 10 weeks. 23.1% of patients having preoperative ESI had more than one level injected, and 66.5% had more than one preoperative ESI treatment. Patients with chronic pain were considerably more likely to have an ESI prior to their surgery [OR 1.62 (1.54, 1.69), p < 0.001]. Patients having preoperative ESI within in close proximity to surgery did not have increased rates of infection, dural tear, neurological complications, or surgical complications; however, they did experience higher rates of reoperations and readmissions than those with no preoperative ESI (p < 0.001)., Conclusion: Half of patients undergoing lumbar spine surgery for stenosis and/or herniation had a preoperative ESI. These were not associated with an increased risk for postoperative complications, even when the ESI was given in close proximity to surgery. Patients with preoperative ESI were more likely to have readmissions and reoperations following surgery.

Many patients are affected by concurrent disease of the hip and spine, undergoing both total hip arthroplasty (THA) and lumbar spinal fusion (LSF). Recent literature demonstrates increased prosthetic dislocation rates in patients with THA done after LSF. Evidence is lacking on which surgery to do first to minimize complications. The purpose of this study was to evaluate the effect of timing between the two procedures on postoperative outcomes., Methods: We queried the Medicare standard analytics files between 2005 and 2014. Four groups were identified and matched by age and sex: THA with previous LSF, LSF with previous THA, THA with spine pathology without fusion, and THA without spine pathology. Revision THA or LSF and bilateral THA were excluded. Comorbidities and Charlson Comorbidity Index were identified. Postoperative complications at 90 days and 2 years were calculated after the most recent surgery. Four-way chi-squared and standard descriptive statistics were calculated., Results: Thirteen thousand one hundred two patients had THA after LSF, 10,482 patients had LSF after THA, 104,820 had THA with spine pathology, and 492,654 had THA without spine pathology. There was no difference in the Charlson Comorbidity Index score between the THA after LSF and LSF after THA groups. There was a statistically significant difference in THA dislocation rate, with LSF after THA at 1.7%, THA without spine pathology at 2.3%, THA with spine pathology at 3.3%, and THA after LSF at 4.6%. There was a statistically significant difference in THA revision rate, with THA without spine pathology at 3.3%, LSF after THA at 3.7%, THA with spine pathology at 4.2%, and THA after LSF at 5.7%., Conclusion: LSF after THA is associated with a reduced dislocation rate compared with THA after LSF. Reasons may include decreasing pelvic mobility in a stable, well-healed THA or early postoperative spine precautions after LSF restricting positions of dislocation., (Copyright © 2019 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.)

Study Design: Retrospective cohort study., Objectives: Assess differences between staged (≤3 days) and same-day surgery in perioperative factors, radiographic measures, and complications., Summary of Background Data: Surgical adult spinal deformity correction may require combined anterior and posterior approaches. To modulate risk, some surgeons perform surgery that is expected to be longer and/or more complex in two stages. Prior studies comparing staged (≥7 days) and same-day surgery demonstrated mixed results and none have examined results with shorter staging intervals., Methods: Retrospective review of adults undergoing combined anterior/posterior approaches for spinal deformity over a 3-year period at a single institution (n=92). Univariate differences between staged and same-day surgery were assessed with chi-squared, Fisher exact, and Mann-Whitney U tests. Generalized estimating equations assessed whether differences in perioperative outcomes between groups remained after adjusting for differences in demographic and surgical characteristics., Results: In univariate analyses, staged surgery was associated with a length of stay (LOS) 3 days longer than same-day surgery (9.2 vs. 6.3 days, p < .001), and greater operative time, blood loss, transfusion requirement, and days in intensive care unit (p < .001 for each). Staged surgery had a higher rate of thrombotic events (p = .011) but did not differ in readmission rates or other complications. Radiographically, improvements in Cobb angle (average 13° vs. 17°, p = .028), lumbar lordosis (average 14° vs. 23°, p = .019), and PI-LL mismatch (average 10° vs. 2° p = .018) were greater for staged surgery, likely related to more extensive use of osteotomies in the staged group. After risk adjustment, taking into account the procedural specifics including longer fusion constructs and greater number of osteotomies, LOS no longer differed between staged and same-day surgery; however, the total operative time was 98 minutes longer for staged surgery (p < .001). Differences in blood loss between groups was accounted for by differences in operative time and patient and surgical characteristics., Conclusions: Although univariate analysis of our results were in accordance with previously published works, multivariate analysis allowing individual case risk adjustment revealed that LOS was not significantly increased in the staged group as reported in previous studies. There was no difference in infection rates as previously described but an increase in thrombotic events was observed., Level of Evidence: Level III., (Copyright © 2019 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Purpose: The presence of Propionibacterium acnes in a substantial component of resected disc specimens obtained from patients undergoing discectomy or microdiscectomy has led to the suggestion that this prominent human skin and oral commensal may exacerbate the pathology of degenerative disc disease. This hypothesis, therefore, raises the exciting possibility that antibiotics could play an important role in treating this debilitating condition. To date, however, little information about antibiotic penetration into the intervertebral disc is available., Methods: Intervertebral disc tissue obtained from 54 microdiscectomy patients given prophylactic cefazolin (n = 25), clindamycin (n = 17) or vancomycin (n = 12) was assayed by high-performance liquid chromatography, with cefaclor as an internal standard, to determine the concentration of antibiotic penetrating into the disc tissue., Results: Intervertebral disc tissues from patients receiving the positively charged antibiotic clindamycin contained a significantly greater percentage of the antibacterial dose than the tissue from patients receiving negatively charged cefazolin (P < 0.0001) and vancomycin, which has a slight positive charge (P < 0.0001)., Conclusion: Positively charged antibiotics appear more appropriate for future studies investigating potential options for the treatment of low-virulence disc infections. These slides can be retrieved under Electronic Supplementary Material.

Background Context: Protein biomarkers associated with lumbar disc disease have been studied as diagnostic indicators and therapeutic targets. Recently, a cartilage degradation product, the fibronectin-aggrecan complex (FAC) identified in the epidural space, has been shown to predict response to lumbar epidural steroid injection in patients with radiculopathy from herniated nucleus pulposus (HNP)., Purpose: Determine the ability of FAC to predict response to microdiscectomy for patients with radiculopathy due to lumbar disc herniation STUDY DESIGN/SETTING: Single-center prospective consecutive cohort study., Patient Sample: Patients with radiculopathy from HNP with concordant symptoms to MRI who underwent microdiscectomy., Outcomes Measures: Oswestry disability index (ODI) and visual analog scores (VAS) were noted at baseline and at 3-month follow-up. Primary outcome of clinical improvement was defined as patients with both a decrease in VAS of at least 3 points and ODI >20 points., Methods: Intraoperative sampling was done via lavage of the excised fragment by ELISA for presence of FAC. Funding for the ELISA was provided by Cytonics, Inc., Results: Seventy-five patients had full complement of data and were included in this analysis. At 3-month follow-up, 57 (76%) patents were "better." There was a statistically significant association of the presence of FAC and clinical improvement (p=.017) with an 85% positive predictive value. Receiver-operating-characteristic (ROC) curve plotting association of FAC and clinical improvement demonstrates an area under the curve (AUC) of 0.66±0.08 (p=.037). Subset analysis of those with weakness on physical examination (n=48) plotting the association of FAC and improvement shows AUC on ROC of 0.81±0.067 (p=.002)., Conclusions: Patients who are "FAC+" are more likely to demonstrate clinical improvement following microdiscectomy. The data suggest that the inflammatory milieu plays a significant role regarding improvement in patients undergoing discectomy for radiculopathy in lumbar HNP, even in those with preoperative weakness. The FAC represents a potential target for treatment in HNP., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background Context: Lumbosacral epidural steroid injections (ESIs) have increased dramatically despite a narrowing of the clinical indications for use. One potential indication is to avoid or delay surgery, yet little information exists regarding surgery rates after ESI., Purpose: The purpose of this research was to determine the proportion of patients having surgery after lumbar ESI for disc herniation or stenosis and to identify the timing and factors associated with this progression., Study Design/setting: This study was a retrospective review of nationally representative administrative claims data from the Truven Health MarketScan databases from 2007 to 2014., Patient Sample: The study cohort was comprised of 179,025 patients (54±15 years, 48% women) having lumbar ESIs for diagnoses of stenosis and/or herniation., Outcome Measures: The primary outcome measure was the time from ESI to surgery., Methods: Inclusion criteria were ESI for stenosis and/or herniation, age ≥18 years, and health plan enrollment for 1 year before ESI to screen for exclusions. Patients were followed longitudinally until they progressed to surgery or had a lapse in enrollment, at which time they were censored. Rates of surgery were assessed with the Kaplan-Meier survival curves. Demographic and treatment factors associated with surgery were assessed with multivariable Cox proportional hazard models. No external funding was procured for this research and the authors' conflicts of interest are not pertinent to the present work., Results: Within 6 months, 12.5% of ESI patients underwent lumbar surgery. By 1 year, 16.9% had surgery, and by 5 years, 26.1% had surgery. Patients with herniation had surgery at rates of up to five-fold to seven-fold higher, with the highest rates of surgery in younger patients and those with both herniation and stenosis. Other concomitant spine diagnoses, male sex, previous tobacco use, and residence a rural areas or regions other than the Northeastern United States were associated with higher surgery rates. Medical comorbidities (previous treatment for drug use, congestive heart failure, obesity, chronic obstructive pulmonary disease, hypercholesterolemia, and other cardiac complications) were associated with lower surgery rates., Conclusions: In the long term, more than one out of every four patients undergoing ESI for lumbar herniation or stenosis subsequently had surgery, and nearly one of six had surgery within the first year. After adjusting for other patient demographics and comorbidities, patients with herniation were more likely have surgery than those with stenosis. The improved understanding of the progression from lumbar ESI to surgery will help to better inform discussions regarding the value of ESI and aid in the shared decision-making process., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Study Design: This is a retrospective cohort study., Objective: To evaluate the long-term outcomes of selective one- to two-level anterior lumbar interbody fusions (ALIFs) in the lower lumbar spine versus continued nonsurgical management., Summary of Background Data: Low back pain associated with lumbar intervertebral disc degeneration is common with substantial economic impact, yet treatment remains controversial. Surgical fusion has previously provided mixed results with limited durable improvement of pain and function., Methods: Seventy-five patients with one or two levels of symptomatic Pfirrmann grades 3 to 5 disc degeneration from L3-S1 were identified. All patients had failed at least 6 months of nonsurgical treatment. Forty-two patients underwent one- or two-level ALIFs; 33 continued multimodal nonsurgical care. Patients were evaluated radiographically and the visual analog pain scale (VAS), Oswestry Disability Index (ODI), EuroQol five dimensions (EQ-5D), and Patient-Reported Outcomes Measurement Information System scores for pain interference, pain intensity, and anxiety. As-treated analysis was performed to evaluate outcomes at a mean follow-up of 7.4 years (range: 2.5-12)., Results: There were no differences in pretreatment demographics or nonsurgical therapy utilization between study arms. At final follow-up, the surgical arm demonstrated lower VAS, ODI, EQ-5D, and Patient-Reported Outcomes Measurement Information System pain intensity scores versus the nonsurgical arm. VAS and ODI scores improved 52.3% and 51.1% in the surgical arm, respectively, versus 15.8% and -0.8% in the nonsurgical arm. Single-level fusions demonstrated improved outcomes versus two-level fusions. The pseudarthrosis rate was 6.5%, with one patient undergoing reoperation. Asymptomatic adjacent segment degeneration was identified in 11.9% of patients., Conclusion: Selective ALIF limited to one or two levels in the lower lumbar spine provided improved pain and function when compared with continued nonsurgical care. ALIF may be a safe and effective treatment for low back pain associated with disc degeneration in select patients who fail nonsurgical management., Level of Evidence: 3.

Background: Pain while sitting is the primary complaint of many patients with lumbar spinal ailments, including those with discogenic low back pain and lumbar disc herniations. There has been little basic research on the different mechanical stresses that different sitting positions place on the spine. To demonstrate the effect of different sitting positions on lumbar intersegmental relationships., Methods: Twenty healthy male volunteer subjects were recruited. Lateral X-rays of the lower lumbar spine were taken in four positions: (I) relaxed lateral standing; (II) "standard" sitting position; (III) sitting on a "kneeling" chair; and (IV) unsupported sitting on a stool. Anterior and posterior disc height, disc space angulation, L1-S1 angulation and interspinous distance were measured., Results: The L1-S1 lordotic angle in the standing position (48.8°±14.7°) was found to be statistically significantly greater than the angle measured with any of the sitting positions: the kneeling chair (34.0°±17.7°); hard-back chair (28.6°±14.3°); and the stool (16.6°±15.6°). Total average disc height (arithmetic sum of average disc heights L2-S1) in the lumbar spine varied with position: standing (40.5±7.75 mm); hard-back chair (38.5±6.9 mm); kneeling chair (38.4±7.9 mm); stool (36.9±7.1 mm). The mean interspinous distance over all the lumbar levels was significantly greater in each of the three seated positions than in the standing position: standing 6.8±4.5 mm; 11.6°±7.5° for the kneeling chair; 12.9±5.8 mm for the hard-back chair; 16.9±7.0 mm for the stool., Conclusions: If segmental flexion and segmental loading are the important biomechanical correlates of pain on sitting, such patients should be most comfortable in a kneeling chair, which most closely approximates the standing position. These basic findings will allow better assessment of different seating positions from an ergonomic perspective, and hopefully lead to improvements in chair design., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.

Background: We previously reported that functional recovery of rats with spinal cord contusions can occur after acute transplantation of neural stem cells distal to the site of injury. To investigate the effects of timing of administration of human neural stem cell (hNSC) distal to the site of spinal cord injury on functional outcomes in an animal model., Methods: Thirty-six adult female Long-Evans hooded rats were randomized into three experimental and three control groups with six animals in each group. The T10 level was exposed via posterior laminectomy, and a moderate spinal cord contusion was induced by the Multicenter Animal Spinal Cord Injury Study Impactor (MASCIS, W.M. Keck Center for Collaborative Neuroscience, Piscataway, NJ, USA). The animals received either an intrathecal injection of hNSCs or control media through a separate distal laminotomy immediately, one week or four weeks after the induced spinal cord injury. Observers were blinded to the interventions. Functional assessment was measured immediately after injury and weekly using the Basso, Beattie, Bresnahan (BBB) locomotor rating score., Results: A statistically significant functional improvement was seen in all three time groups when compared to their controls (acute, mean 9.2 vs. 4.5, P=0.016; subacute, mean 11.1 vs. 6.8, P=0.042; chronic, mean 11.3 vs. 5.8, P=0.035). Although there was no significant difference in the final BBB scores comparing the groups that received hNSCs, the group which achieved the greatest improvement from the time of cell injection was the subacute group (+10.3) and was significantly greater than the chronic group (+5.1, P=0.02)., Conclusions: The distal intrathecal transplantation of hNSCs into the contused spinal cord of a rat led to significant functional recovery of the spinal cord when injected in the acute, subacute and chronic phases of spinal cord injury (SCI), although the greatest gains appeared to be in the subacute timing group., Competing Interests: Conflicts of Interest: AI Kharazi is an employee of Stemedica and served as a consultant to this project regarding cell preparation. He was otherwise not involved in any animal procedures, data acquisition or data analysis. The other authors have no conflicts of interest to declare.

Purpose: To determine the presence of infectious microorganisms in the herniated discs of immunocompetent patients, using methodology that we hoped would be of higher sensitivity and specificity than has been reported in the past. Recent studies have demonstrated a significant rate of positive cultures for low virulent organisms in excised HNP samples (range 19-53%). These studies have served as the theoretical basis for a pilot trial, and then, a well done prospective randomized trial that demonstrated that systemic treatment with antibiotics may yield lasting improvements in a subset of patients with axial back pain. Whether the reported positive cultures in discectomy specimens represent true positives is as yet not proven, and critically important if underlying the basis of therapeutic approaches for chronic low back pain., Methods: This consecutive case series from a single academic center included 44 patients with radiculopathy and MRI findings of lumbar HNP. Patients elected for lumbar microdiscectomy after failure of conservative management. All patients received primary surgery at a single spinal level in the absence of immune compromise. Excised disc material was analyzed with a real-time PCR assay targeting the 16S ribosomal RNA gene followed by amplicon sequencing. No concurrent cultures were performed. Inclusion criteria were as follows: sensory or motor symptoms in a single lumbar nerve distribution; positive physical examination findings including positive straight leg raise test, distributional weakness, and/or a diminished deep tendon reflexes; and magnetic resonance imaging of the lumbar spine positive for HNP in a distribution correlating with the radicular complaint., Results: The PCR assay for the 16S rRNA sequence was negative in all 44 patients (100%). 95% CI 0-8%., Conclusions: Based on the data presented here, there does not appear to be a significant underlying rate of bacterial disc infection in immunocompetent patients presenting with radiculopathy from disc herniation.

Study Design: Cross-sectional cohort analysis of patients with Modic Changes (MC)., Objective: Our goal was to characterize the molecular and cellular features of MC bone marrow and adjacent discs. We hypothesized that MC associate with biologic cross-talk between discs and bone marrow, the presence of which may have both diagnostic and therapeutic implications., Background Data: MC are vertebral bone marrow lesions that can be a diagnostic indicator for discogenic low back pain. Yet, the pathobiology of MC is largely unknown., Methods: Patients with Modic type 1 or 2 changes (MC1, MC2) undergoing at least 2-level lumbar interbody fusion with one surgical level having MC and one without MC (control level). Two discs (MC, control) and two bone marrow aspirates (MC, control) were collected per patient. Marrow cellularity was analyzed using flow cytometry. Myelopoietic differentiation potential of bone marrow cells was quantified to gauge marrow function, as was the relative gene expression profiles of the marrow and disc cells. Disc/bone marrow cross-talk was assessed by comparing MC disc/bone marrow features relative to unaffected levels., Results: Thirteen MC1 and eleven MC2 patients were included. We observed pro-osteoclastic changes in MC2 discs, an inflammatory dysmyelopoiesis with fibrogenic changes in MC1 and MC2 marrow, and up-regulation of neurotrophic receptors in MC1 and MC2 bone marrow and discs., Conclusion: Our data reveal a fibrogenic and pro-inflammatory cross-talk between MC bone marrow and adjacent discs. This provides insight into the pain generator at MC levels and informs novel therapeutic targets for treatment of MC-associated LBP.

Background: In previous studies, Propionibacterium acnes was cultured from intervertebral disc tissue of ~25% of patients undergoing microdiscectomy, suggesting a possible link between chronic bacterial infection and disc degeneration. However, given the prominence of P. acnes as a skin commensal, such analyses often struggled to exclude the alternate possibility that these organisms represent perioperative microbiologic contamination. This investigation seeks to validate P. acnes prevalence in resected disc cultures, while providing microscopic evidence of P. acnes biofilm in the intervertebral discs., Methods: Specimens from 368 patients undergoing microdiscectomy for disc herniation were divided into several fragments, one being homogenized, subjected to quantitative anaerobic culture, and assessed for bacterial growth, and a second fragment frozen for additional analyses. Colonies were identified by MALDI-TOF mass spectrometry and P. acnes phylotyping was conducted by multiplex PCR. For a sub-set of specimens, bacteria localization within the disc was assessed by microscopy using confocal laser scanning and FISH., Results: Bacteria were cultured from 162 discs (44%), including 119 cases (32.3%) with P. acnes. In 89 cases, P. acnes was cultured exclusively; in 30 cases, it was isolated in combination with other bacteria (primarily coagulase-negative Staphylococcus spp.) Among positive specimens, the median P. acnes bacterial burden was 350 CFU/g (12 - ~20,000 CFU/g). Thirty-eight P. acnes isolates were subjected to molecular sub-typing, identifying 4 of 6 defined phylogroups: IA1, IB, IC, and II. Eight culture-positive specimens were evaluated by fluorescence microscopy and revealed P. acnes in situ. Notably, these bacteria demonstrated a biofilm distribution within the disc matrix. P. acnes bacteria were more prevalent in males than females (39% vs. 23%, p = 0.0013)., Conclusions: This study confirms that P. acnes is prevalent in herniated disc tissue. Moreover, it provides the first visual evidence of P. acnes biofilms within such specimens, consistent with infection rather than microbiologic contamination.

Background: The relationship between intervertebral disc degeneration and chronic infection by Propionibacterium acnes is controversial with contradictory evidence available in the literature. Previous studies investigating these relationships were under-powered and fraught with methodical differences; moreover, they have not taken into consideration P. acnes' ability to form biofilms or attempted to quantitate the bioburden with regard to determining bacterial counts/genome equivalents as criteria to differentiate true infection from contamination. The aim of this prospective cross-sectional study was to determine the prevalence of P. acnes in patients undergoing lumbar disc microdiscectomy., Methods and Findings: The sample consisted of 290 adult patients undergoing lumbar microdiscectomy for symptomatic lumbar disc herniation. An intraoperative biopsy and pre-operative clinical data were taken in all cases. One biopsy fragment was homogenized and used for quantitative anaerobic culture and a second was frozen and used for real-time PCR-based quantification of P. acnes genomes. P. acnes was identified in 115 cases (40%), coagulase-negative staphylococci in 31 cases (11%) and alpha-hemolytic streptococci in 8 cases (3%). P. acnes counts ranged from 100 to 9000 CFU/ml with a median of 400 CFU/ml. The prevalence of intervertebral discs with abundant P. acnes (≥ 1x103 CFU/ml) was 11% (39 cases). There was significant correlation between the bacterial counts obtained by culture and the number of P. acnes genomes detected by real-time PCR (r = 0.4363, p<0.0001)., Conclusions: In a large series of patients, the prevalence of discs with abundant P. acnes was 11%. We believe, disc tissue homogenization releases P. acnes from the biofilm so that they can then potentially be cultured, reducing the rate of false-negative cultures. Further, quantification study revealing significant bioburden based on both culture and real-time PCR minimize the likelihood that observed findings are due to contamination and supports the hypothesis P. acnes acts as a pathogen in these cases of degenerative disc disease.

Background Context: Prior studies have demonstrated the superiority of decompression and fusion over decompression alone for the treatment of lumbar degenerative spondylolisthesis with spinal stenosis. More recent studies have investigated whether nonfusion stabilization could provide durable clinical improvement after decompression and fusion., Purpose: To examine the clinical safety and effectiveness of decompression and implantation of a novel flexion restricting paraspinous tension band (PTB) for patients with degenerative spondylolisthesis., Study Design: A prospective clinical study., Patient Sample: Forty-one patients (7 men and 34 women) aged 45 to 83 years (68.2 ± 9.0) were recruited with symptomatic spinal stenosis and Meyerding Grade 1 or 2 degenerative spondylolisthesis at L3-L4 (8) or L4-L5 (33)., Outcome Measures: Self-reported measures included visual analog scale (VAS) for leg, back, and hip pain and the Oswestry Disability Index (ODI). Physiologic measures included quantitative and qualitative radiographic analysis performed by an independent core laboratory., Methods: Patients with lumbar degenerative spondylolisthesis and stenosis were prospectively enrolled at four European spine centers with independent monitoring of data. Clinical and radiographic outcome data collected preoperatively were compared with data collected at 3, 6, 12, and 24 months after surgery. This study was sponsored by the PTB manufacturer (Simpirica Spine, Inc., San Carlos, CA, USA), including institutional research support grants to the participating centers totaling approximately US $172,000., Results: Statistically significant improvements and clinically important effect sizes were seen for all pain and disability measurements. At 24 months follow-up, ODI scores were reduced by an average of 25.4 points (59%) and maximum leg pain on VAS by 48.1 mm (65%). Back pain VAS scores improved from 54.1 by an average of 28.5 points (53%). There was one postoperative wound infection (2.4%) and an overall reoperation rate of 12%. Eighty-two percent patients available for 24 months follow-up with a PTB in situ had a reduction in ODI of greater than 15 points and 74% had a reduction in maximum leg pain VAS of greater than 20 mm. According to Odom criteria, most of these patients (82%) had an excellent or good outcome with all except one patient satisfied with surgery. As measured by the independent core laboratory, there was no significant increase in spondylolisthesis, segmental flexion-extension range of motion, or translation and no loss of lordosis in the patients with PTB at the 2 years follow-up., Conclusions: Patients with degenerative spondylolisthesis and spinal stenosis treated with decompression and PTB demonstrated no progressive instability at 2 years follow-up. Excellent/good outcomes and significant improvements in patient-reported pain and disability scores were still observed at 2 years, with no evidence of implant failure or migration. Further study of this treatment method is warranted to validate these findings., (Copyright © 2015. Published by Elsevier Inc.)

Study Design: Biomechanical human cadaveric study., Objective: We hypothesized that increasing compressive preload will reduce the segmental instability after nucleotomy, posterior ligament resection, and decompressive surgery., Summary of Background Data: The human spine experiences significant compressive preloads in vivo due to spinal musculature and gravity. Although the effect of destabilization procedures on spinal motion has been studied, the effect of compressive preload on the motion response of destabilized, multisegment lumbar spines has not been reported., Methods: Eight human cadaveric spines (L1-sacrum, 51.4 ± 14.1 yr) were tested intact, after L4-L5 nucleotomy, after interspinous and supraspinous ligaments transection, and after midline decompression (bilateral laminotomy, partial medial facetectomy, and foraminotomy). Specimens were loaded in flexion (8 Nm) and extension (6 Nm) under 0-N, 200-N, and 400-N compressive follower preload. L4-L5 range of motion (ROM) and flexion stiffness in the high-flexibility zone were analyzed using repeated-measures analysis of variance and multiple comparisons with the Bonferroni correction., Results: With a fixed set of loading conditions, a progressive increase in segmental ROM along with expansion of the high-flexibility zone (decrease of flexion stiffness) was noted with serial destabilizations. Application of increasing compressive preload did not substantially change segmental ROM, but did significantly increase the segmental stiffness in the high-flexibility zone. In the most destabilized condition, 400-N preload did not return the segmental stiffness to intact levels., Conclusion: Anatomical alterations representing degenerative and iatrogenic instabilities are associated with significant increases in segmental ROM and decreased segmental stiffness. Although application of compressive preload, mimicking the effect of increased axial muscular activity, significantly increased the segmental stiffness, it was not restored to intact levels; thereby suggesting that core strengthening alone may not compensate for the loss of structural stability associated with midline surgical decompression. This suggests that there may be a role for surgical implants or interventions that specifically increase flexion stiffness and limit flexion ROM to counteract the iatrogenic instability resulting from surgical decompression., Level of Evidence: N/A.

Purpose: Development of a dynamic stabilization system often involves costly and time-consuming design iterations, testing and computational modeling. The aims of this study were (1) develop a simple parametric model of lumbar flexion instability and use this model to identify the appropriate stiffness of a flexion restricting stabilization system (FRSS), and (2) in a cadaveric experiment, validate the predictive value of the parametric model., Methods: Literature was surveyed for typical parameters of intact and destabilized spines: stiffness in the high flexibility zone (HFZ) and high stiffness zone, and size of the HFZ. These values were used to construct a bilinear parametric model of flexion kinematics of intact and destabilized lumbar spines. FRSS implantation was modeled by iteratively superimposing constant flexion stiffnesses onto the parametric model. Five cadaveric lumbar spines were tested intact; after L4-L5 destabilization (nucleotomy, midline decompression); and after FRSS implantation. Specimens were loaded in flexion/extension (8 Nm/6 Nm) with 400 N follower load to characterize kinematics for comparison with the parametric model., Results: To accomplish the goal of reducing ROM to intact levels and increasing stiffness to approximately 50 % greater than intact levels, flexion stiffness contributed by the FRSS was determined to be 0.5 Nm/deg using the parametric model. In biomechanical testing, the FRSS restored ROM of the destabilized segment from 146 ± 13 to 105 ± 21 % of intact, and stiffness in the HFZ from 41 ± 7 to 135 ± 38 % of intact., Conclusions: Testing demonstrated excellent predictive value of the parametric model, and that the FRSS attained the desired biomechanical performance developed with the model. A simple parametric model may allow efficient optimization of kinematic design parameters.

Object: There has been increasing interest in spinous process tension band devices, as distinct from spinous process spacers and plates. The purpose of this study was to load spinous processes caudally at L-4 and cranially at L-5 parallel to the long axis of the spine in a biomechanical model of tension band loading. The goal was to provide normative data for the design of a spinous process tension band device after varying degrees of surgical decompression and across varying bone mineral densities (BMDs)., Methods: Fresh-frozen L4-5 lumbar vertebrae pairs were divided into 3 surgical groups: intact, midline-sparing decompression (laminotomy and medial facetectomy), and midline decompression with foraminotomy (one-half of spinous process resected, laminotomy, and medial facetectomy). After decompression, specimens were disarticulated into isolated L-4 and L-5 vertebrae. Each vertebra was loaded to failure in a caudal (L-4) or cranial (L-5) direction parallel to the long axis of the spine via a 6-mm-wide strap looped around the spinous process. Failure strength and mode were recorded., Results: Seventeen L-4 and L-5 lumbar vertebrae were tested from 17 cadavers. There were 10 male (59%) and 7 female (41%) cadavers, with a mean age of 66.6 ± 16.5 years (range 41-100 years) and a mean BMD of 1 ± 0.23 g/cm(2) (range 0.66-1.34 g/cm(2)); the mean is expressed ± SD throughout. For data analysis, specimens were grouped into those with no or midline-sparing decompression (Group 1: 11 of 17) and those with midline decompression (Group 2: 6 of 17). At L-4, the mean failure strength for Group 1 was 453 ± 162 N, and for Group 2 it was 264 ± 99 N (p = 0.02; Cohen's d = 1.4). At L-5, the mean failure strength for Group 1 was 517 ± 190 N, and for Group 2 it was 269 ± 184 N (p = 0.02; Cohen's d = 1.3). There was no significant difference in failure strength between the intact and midline-sparing decompression groups at L-4 (p = 0.91) or L-5 (p = 0.41)., Conclusions: Across specimens with a wide range of BMDs, midline-sparing decompression was not found to decrease the mean failure strength of the L-4 and L-5 spinous processes (453 and 517 N, respectively), whereas midline surgical decompression decreased the failure strength of these processes (264 and 269 N, respectively) in a biomechanical model of tension band loading relevant to the design of a tension band device.

Study Design: A consecutive case series from a single center of patients undergoing primary microdiscectomy for lumbar herniated nucleus pulposus (HNP) who received microbiologic laboratory culture of excised disc material., Objective: To determine the prevalence of positive bacterial cultures in the disc material of immunocompetent patients without diabetes mellitus or other immune compromise., Summary of Background Data: The intradiscal space is a physiologically tenuous environment in terms of oxygen tension, pH, and vascularity. This space may be susceptible to indolent infections with an unknown effect on the pathogenesis of HNP., Methods: This case series included 52 patients with radiculopathy and magnetic resonance imaging positive for HNP who elected for lumbar microdiscectomy after failure of conservative management. All patients received primary surgery at a single spinal level in the absence of diabetes mellitus, systemic steroid use, chemotherapy, other immune compromise, or prior lumbar surgery. Excised disc material was sent for routine bacterial culture. No special culture techniques were used to improve the yield of positive cultures., Results: Cultures were positive in 10 patients (19.2%). Propionibacterium acnes was the sole organism isolated in 7 (13.5%), with Peptostreptococcus and Staphylococcus species accounting for the remainder. There were 24 women (46.2%) and 28 men (53.8%) with a mean age of 43.9 years (SE 1.8). Duration of symptoms was greater than 12 weeks in 35 patients (67.3%). Onset of symptoms was insidious in 22 patients (42.3%), sudden in 16 (30.8%), and the history was unclear in the remainder. Prior epidural steroid injection was received by 17 patients (32.7%), and 11 patients had a history of smoking (21.2%). None of these variables was significantly different in patients with positive and negative cultures (P >0.05)., Conclusions: P. acnes was isolated by routine laboratory culture of excised disc material in 13.5% of immunocompetent patients undergoing primary single level discectomy for radiculopathy with lumbar HNP; other organisms were isolated in 6% of patients., Level of Evidence: Diagnostic level of evidence III.

Background Context: Interspinous process devices represent an emerging treatment for neurogenic intermittent claudication resulting from lumbar spinal stenosis. Most published descriptions of the operative technique involve treatment of patients in the modified lateral decubitus knee-chest position (modified lateral decubitus), and yet many surgeons have begun to perform the procedure in various prone positions. The patient's positioning on the operating room table seems likely to influence resting interspinous distance, and thus implant sizing and possibly the risk of intraoperative spinous process fracture. The intersegmental lumbar effect of variants on operative prone positioning compared with the modified lateral decubitus position has not been studied., Purpose: We performed this study to determine the comparative differences in interspinous distance and intersegmental angulation effected by the lateral decubitus knee-chest position and the variants on prone positioning used in practice., Study Design/setting: Experimental human radiographic study., Patient Sample: Twenty healthy male volunteers with a mean age of 43.6+/-10.8 years (range, 24-63), without chronic back pain, symptoms of neurogenic claudication, or history of lumbar surgery were enrolled., Outcome Measures: Interspinous distance, anterior and posterior disc heights, disc angulation were measured on PACS monitor., Methods: Lateral X-rays were taken of the lower lumbar spine in each of four different surgical positions (modified lateral decubitus, Andrews frame, Wilson frame, and Jackson frame). Statistical analysis was performed on the resultant data points to assess the significance of the effect of the position of the subject on intersegmental spacing and angulation., Results: The 20 enrollees had a mean age of 43.6+/-10.8 years (range, 24-63). The mean interspinous distance at the L4-L5 level was greatest on the Andrews table (23.5+/-8.3mm) followed by the modified lateral decubitus position (19.6+/-5.1mm), the Wilson frame (15.6+/-4.6mm), and then the Jackson frame (10.1+/-4.7mm; significantly less than all other positions p< or =.036). Mean segmental extension at the L4-L5 level was least in the modified lateral decubitus position (-0.1 degrees +/-2.9 degrees ); this was statistically similar to extension on the Andrews table (1.5 degrees +/-4.7 degrees , p=1.0), but significantly less than that recorded on the Wilson frame (4.6 degrees +/-3.1 degrees , p<.001), and also significantly less than that recorded on the Jackson frame (p< or =.001). Similar differences in segmental measurements were observed at L3-L4., Conclusions: Prone positioning of patients in flexion on the operating table using the Andrews table or Wilson frame resulted in similar lumbar interspinous distance compared with the modified lateral decubitus position. Prone positioning on the Jackson frame resulted in statistically less interspinous distance than all other positions. Positioning on the Andrews table resulted in similar segmental angulation to the modified lateral decubitus position. Extrapolation from these data, obtained in healthy males younger than the typical age of patients treated with interspinous distraction devices, should clearly be done with caution. However, it seems reasonable to suggest that performing these procedures in the prone position using the Andrews table (greatest interspinous distance) is unlikely to result in the placement of significantly undersized implants, or significantly increase the force required to insert an implant.

Study Design: Ex vivo biomechanical study using osteoporotic cadaveric fractured vertebral bodies., Objective: To investigate the behavior of fractured osteoporotic vertebral bodies treated with either vertebroplasty or kyphoplasty under repetitive loading conditions., Summary of Background Data: Vertebroplasty and kyphoplasty are newer alternatives for the treatment of osteoporotic vertebral fractures. Loading conditions that can lead to fractures treated with these methods will likely be encountered subsequently; as such, it is important to understand differences in the biomechanical behavior of the resultant constructs., Methods: There were 7 pairs of osteoporotic T8 and T10 vertebral bodies cyclically loaded to produce a vertebral compression fracture. Of each pair, one was assigned to the kyphoplasty group and the other to the vertebroplasty group. After treatment, specimens were cyclically loaded to 100,000 cycles, between 20% and 70% of the predicted failure load., Results: Height was restored with kyphoplasty, but the vertebral bodies showed significant height loss during cyclic loading. Vertebroplasty specimens had higher compression stiffness and smaller height reduction., Conclusions: Under repetitive loading conditions, fractured vertebral bodies treated with kyphoplasty were initially taller, but because of a progressive loss of height during loading, the resulting constructs were shorter after 100,000 cycles than those treated with vertebroplasty.

Study Design: Prospective observational study with historical control. The prospective study population consisted of 30 patients undergoing a posterior lumbar subtotal discectomy for lumbar disc herniation. This group was compared to a historical cohort of 46 patients treated with limited discectomy alone., Objective: To compare clinical outcomes after limited versus subtotal discectomy for lumbar disc herniations., Summary of Background Data: Large posterior anular defects found at posterior discectomy have been associated with more frequent reherniation when treated with limited discectomy (i.e., removing only extruded or loose intervertebral fragments). A trial of more aggressive discectomy (subtotal) was undertaken to determine if the rate of reherniation could be decreased with this technique., Methods: A total of 30 patients undergoing a posterior lumbar discectomy for lumbar disc herniation were treated with an aggressive (subtotal) resection of intervertebral disc material after removal of the extruded or protruded fragments. This group was compared against a historical cohort of 46 patients treated with limited discectomy alone. Reherniation rates and clinical outcomes were determined by independent evaluation at 6, 12, and 24 months after surgery., Results: The reherniation rate in the limited discectomy group was 18% versus 9% in the subtotal discectomy group at follow-up (P = 0.1). However, the back pain (visual analog scale) (P = 0.02) and Oswestry scores (P = 0.06) were worse in the subtotal discectomy group at 12-month follow-up. Time to return to work was longer, and pain medication usage was higher in the subtotal discectomy group at 12-month follow-up. Despite a trend toward a higher reherniation rate, the patient satisfaction at 2-year follow-up was higher in the limited discectomy group., Conclusions: The more aggressive removal of remaining intervertebral disc material may decrease the risk of reherniation, but the overall outcome was less satisfactory, especially during the first year after surgery.

Study Design: Retrospective data review of positive disc injections at low pressures among subjects without chronic low back pain (LBP) illness compared to patients with chronic LBP undergoing Discography., Objective: To test the hypothesis that false-positive injections during Discography can effectively be eliminated by defining the positive injection criteria to include only those discs in which pain is produced with low injection pressure injections., Summary of Background Data: The use of lumbar Discography as a diagnostic tool remains controversial. Studies have shown that disc injections among subjects asymptomatic of clinical LBP will produce painful injections in a significant proportion of subjects, rendering the interpretation of positive diskograms in clinical practice problematic. It has been argued that lumbar disc injections at low pressure may be clinically different from those at higher pressure and that a guideline accepting only of low-pressure injections will effectively eliminate false positives., Methods: A total of 69 volunteers with no clinically significant LBP undergoing experimental lumbar Discography were analyzed. There were 4 subgroups of this study cohort: no LBP, no chronic pain (n = 10); no LBP, chronic pain (n = 14); no LBP, previous lumbar discectomy (n = 20); and minor benign "backache" (n = 25). Pressure measurements during injection were made, and the pressure at which a significant pain response was elicited was recorded. This result was compared to the pain response and pressure profiles of 52 patients undergoing Discography for chronic LBP illness in consideration of treatment. Raters who were blinded to the subject's study group scored the studies. Diskogram morphology, pain response, and concordance, as well as magnetic resonance imaging, plain radiographs, psychometric testing (Distress and Risk Assessment Method), and compensation history were documented for each group. A low-pressure positive was defined as significant pain elicited less than 22 psi more than opening pressure., Results: The number and percent of individuals with at least 1 low-pressure positive disc in the experimental group were 17 of 69 (25%) and in the clinical LBP group 14 of 52 (27%). The percentage of subjects with positive pain in the different experimental subgroups was: no LBP, no chronic pain 0/10 (0%); no LBP, chronic pain 5/14 (36%); no LBP, previous lumbar discectomy 5/20 (25%); and minor benign "backache" 7/25 (28%). Positive injections correlated with anular disruption, abnormal psychometric findings, and chronic pain states., Conclusions: The analysis shows that the rate of low-pressure painful injections in subjects without chronic LBP illness is approximately 25%, and correlates with both anatomic and psychosocial factors. In certain subgroups, this may represent an unacceptable risk of false-positive results.

Study Design: Measurement of the monotonic and fatigue properties of osteoporotic thoracic vertebral bodies., Objectives: To determine the loading values at which osteoporotic vertebral bodies are susceptible to failure., Summary of Background Data: Vertebral compression fractures are the most common osteoporotic fracture. Eighty-three percent of vertebral compression fractures are caused by moderate or less trauma, and there is not a specific traumatic event in 59% of these cases. Fatigue loading can lead to premature failure, although the relationship between loading and cycles to failure is not well established., Methods: Eighteen osteoporotic thoracic vertebral bodies were tested in monotonic compression to determine the correlation between the bone mineral content and the ultimate compressive load. Seventeen osteoporotic thoracic vertebral bodies were cyclically loaded at varying percentages of the ultimate compressive load until failure to determine the relationship between loading and fatigue life., Results: The bone mineral content was linearly correlated with ultimate compressive load. Based on our regression analysis, a 10% decrease in bone mineral content will lead to an approximate 10% decrease in ultimate compressive load. The percentage of ultimate compressive load was inversely correlated to the logarithm of cycles to failure, with specimens loaded at 60%, 70%, and 80% of ultimate compressive load lasting on average 5.6 x 10, 4.0 x 10, and 31 cycles to failure, respectively., Conclusions: The bone mineral content is a strong predictor of the ultimate compressive load, while the percentage of the ultimate compressive load is a strong predictor of the cycles to failure for osteoporotic thoracic vertebral bodies.

Background Context: A range of morphologic and psychosocial variables has been suggested as risk factors for serious low back pain (LBP) illness. Although the relative contributions of structural and psychosocial variables are intensely debated, the validity of differing hypotheses has proven difficult to test because the incidence of serious disabling LBP illness is low in healthy subjects. These factors dictate the requirement for large sample sizes, extensive structural imaging and extended longitudinal study. Previous studies included either small cohorts with intensive imaging testing or large population studies that do not establish a detailed morphologic baseline., Purpose: To establish, using a strict patient sample design, the relative contribution of structural and psychosocial determinants of serious LBP illness among subjects with no previous LBP disability or clinical LBP illness., Study Design/setting: A prospective, longitudinal study of subjects with high risk factors for serious LBP as determined by structural and psychosocial characteristics., Patient Sample: One hundred subjects with known mild persistent low back pain and a 2:1 ratio of chronic (non-lumbar) pain syndrome were recruited from a study population with a predisposition to disc degenerative disease, to undergo baseline examination, testing and 5-year follow-up., Outcome Measures: Observations were made at 6-month intervals over 4 to 6 years (mean, 5.3) for the after primary outcomes measures: episodes of serious back pain (visual analogue scale [VAS] > or =6), episodes of occupational disability less than 1 week, episodes of occupational disability for 1 week, remission episodes of all back pain symptoms at least 6 months and medical visits primarily for LBP evaluation and treatment., Methods: Lumbar magnetic resonance imaging (MRI), lumbar provocative discography (in psychometrically normal subjects), physical examinations, medical and work histories and psychometric testing were performed at baseline. Imaging and psychometric testing were graded by blinded examiners. A scripted interview was conducted every 6 months during follow-up by independent research assistants who also were blinded to patient baseline data. The interview covered interval medical, occupational and accident or injury histories., Results: Psychosocial variables strongly predicted both long- and short-term disability events, duration and health-care visits for LBP problems (p<0.0001-0.004). The likelihood of a sustained remission from the baseline persistent (subclinical) LBP appeared to be linked to occupation factors (leaving a heavy labor occupation; p=0.0001), neurophysiologic variables (chronic nonlumbar pain; p=0.0002) and psychometric profiles at baseline (DRAM and FABQ-PA; p=0.003-0.002). Of the structural findings measured only moderate or severe Modic changes of the vertebral end plate were weakly associated with an adverse outcome. A positive provocative discogram at baseline did not predict any future adverse event., Conclusion: The development of serious LBP disability in a cohort of subjects with both structural and psychosocial risk factors was strongly predicted by baseline psychosocial variables. Structural variables on both MRI and discography testing at baseline had only weak association with back pain episodes and no association with disability or future medical care.

Background Context: Whether discographic injections would be positive in subjects with benign persistent "backache" who are not seeking treatment is unknown. This information is important, because benign backache undoubtedly co-exists in patients with chronic low back pain (CLBP) illness that is not discogenicin origin. If these subjects had a high rate of positive discography, the high background incidence of common backache would allow many positive tests in patients in whom discogenic processes were unrelated to their severe CLBP illness. Conversely, if subjects with benign low back pain rarely if ever had significant concordant pain reproduction on disc injections, the basic tenet of discographic diagnosis would be strengthened., Purpose: To compare, using a strict experimental design, the relative pain and concordancy response to provocative discography in subjects with clinically insignificant "backache" and clinical subjects with CLBP illness considering surgical treatment., Study Design: Comparison of experimental disc injections in subjects with persistent mild backache and those with chronic low back pain (CLBP) illness., Patient Sample: Twenty-five subjects with mild persistent low back pain (LBP) were recruited for an experimental discography study. Subjects were recruited from a clinical study of patients having had cervical spine surgery. Inclusion criteria required that subjects not be receiving or seeking medical treatment for LBP, be taking no medications for backache, have no activity restrictions because of LBP, and have normal psychometric scores. To more closely approximate the pain behavior in CLBP illness, 50% (12) of the "backache" group were recruited with a chronic painful condition (neck/shoulder) unrelated to the low back. CLBP subjects, patients coming to discography for consideration of surgical treatment, were used as control subjects., Outcome Measures: Results of discography were determined using the criteria of Walsh et al.: pain response of 3 or greater, two or more pain behaviors, a negative "control" discographic injection, and a similar or exact concordancy rating., Methods: Discography was performed on experimental subjects and control patients. Experienced raters, who were blinded to control versus experimental status of the subjects, scored the magnetic resonance image, discogram, psychometric tests and discography videotapes of the subjects' pain behavior., Results: Thirteen of 25 volunteer subjects had pain rated as "bad" or worse with disc injection. There were 12 painful and fully concordant disc injections in 9 of these 25 "backache" subjects (36%). These injections met all the Walsh et al. criteria for a positive diagnosis of discogenic pain. All positive discs had annular disruption to or through the outer annulus. Of the 9 subjects with positive discograms, 3 had no chronic pain states and 6 did. All subjects with positive injections had negative control discs. In comparison, in 52 subjects with CLBP illness 38 (73%) had at least one positive disc injection., Conclusions: In a group of volunteer subjects with persistent "backache," 36% were found to have significant pain on disc injection, which is reported to be concordant with their usual pain. The presence of positive concordant pain responses and negative control discs in 33% of subjects without CLBP illness seriously challenges the specificity of provocative discography in identifying a clinically relevant spinal pathology.

Background Context: Discography is used today as the basis of the diagnosis of discogenic back and neck pain. As such, it plays a pivotal role in the formulation of treatment plans for patients complaining of chronic axial spine pain., Purpose: A brief history of discography is described here, followed by a discussion of the current uses of discography, the technique involved, and recent studies questioning its validity., Study Design/setting: A selective review of discography articles from peer-reviewed literature from 1967 to 2000 is provided. We included articles analyzing the validity of discography as well as those concerning its proper use, technique, and complications., Methods: Articles relevant to the subject of discography were systematically reviewed for recommendations regarding technique, the interpretation of results, and conclusions regarding its validity., Results: The specificity of discography is dramatically affected by the characteristics of the patient examined. In a patient with chronic pain states and psychiatric risk factors, the specificity was determined to be at most 20%. In healthy patients with no chronic pain states and a normal psychiatric profile, the specificity was found to be at most 90%. The ability of a patient to determine reliably the concordance of pain provoked during discography is poor. We could find no data addressing the sensitivity of the study., Conclusions: Clinicians who use discography to determine treatment pathways for their patients need to critically examine the validity of the test. Recent studies examining the specificity of discography have led us to proceed much more cautiously in interpreting the results of discography.