Lumbar Degenerative Disc Disease: Current and Future Concepts of Diagnosis and Management

Low back pain as a result of degenerative disc disease imparts a large socioeconomic impact on the health care system. Traditional concepts for treatment of lumbar disc degeneration have aimed at symptomatic relief by limiting motion in the lumbar spine, but novel treatment strategies involving stem cells, growth factors, and gene therapy have the theoretical potential to prevent, slow, or even reverse disc degeneration. Understanding the pathophysiological basis of disc degeneration is essential for the development of treatment strategies that target the underlying mechanisms of disc degeneration rather than the downstream symptom of pain. Such strategies ideally aim to induce disc regeneration or to replace the degenerated disc. However, at present, treatment options for degenerative disc disease remain suboptimal, and development and outcomes of novel treatment options currently have to be considered unpredictable

Surgical versus nonsurgical treatment for lumbar degenerative spondylolisthesis.

BACKGROUND: Management of degenerative spondylolisthesis with spinal stenosis is controversial. Surgery is widely used, but its effectiveness in comparison with that of nonsurgical treatment has not been demonstrated in controlled trials. METHODS: Surgical candidates from 13 centers in 11 U.S. states who had at least 12 weeks of symptoms and image-confirmed degenerative spondylolisthesis were offered enrollment in a randomized cohort or an observational cohort. Treatment was standard decompressive laminectomy (with or without fusion) or usual nonsurgical care. The primary outcome measures were the Medical Outcomes Study 36-Item Short-Form General Health Survey (SF-36) bodily pain and physical function scores (100-point scales, with higher scores indicating less severe symptoms) and the modified Oswestry Disability Index (100-point scale, with lower scores indicating less severe symptoms) at 6 weeks, 3 months, 6 months, 1 year, and 2 years. RESULTS: We enrolled 304 patients in the randomized cohort and 303 in the observational cohort. The baseline characteristics of the two cohorts were similar. The one-year crossover rates were high in the randomized cohort (approximately 40% in each direction) but moderate in the observational cohort (17% crossover to surgery and 3% crossover to nonsurgical care). The intention-to-treat analysis for the randomized cohort showed no statistically significant effects for the primary outcomes. The as-treated analysis for both cohorts combined showed a significant advantage for surgery at 3 months that increased at 1 year and diminished only slightly at 2 years. The treatment effects at 2 years were 18.1 for bodily pain (95% confidence interval [CI], 14.5 to 21.7), 18.3 for physical function (95% CI, 14.6 to 21.9), and -16.7 for the Oswestry Disability Index (95% CI, -19.5 to -13.9). There was little evidence of harm from either treatment. CONCLUSIONS: In nonrandomized as-treated comparisons with careful control for potentially confounding baseline factors, patients with degenerative spondylolisthesis and spinal stenosis treated surgically showed substantially greater improvement in pain and function during a period of 2 years than patients treated nonsurgically. (ClinicalTrials.gov number, NCT00000409 [ClinicalTrials.gov].)

A Comparative Study of Lateral Lumbar Interbody Fusion and Posterior Lumbar Interbody Fusion in Degenerative Lumbar Spondylolisthesis

Study DesignLevel 4 retrospective review.PurposeTo compare the radiographic and clinical outcomes between posterior lumbar interbody fusion (PLIF) and lateral lumbar interbody fusion (LLIF) with posterior segmental spinal instrumentation (SSI) for degenerative lumbar spondylolisthesis.Overview of LiteratureBoth PLIF and LLIF have been performed for degenerative spondylolisthesis with good results, but no study has directly compared these two techniques so far.MethodsThe electronic medical and radiographic records of 78 matched patients were analyzed. In one group, 39 patients underwent PLIF with SSI at 41 levels (L3-4/L4-5), while in the other group, 39 patients underwent the LLIF procedure at 48 levels (L3-4/L4-5). Radiological outcomes such as restoration of disc height and neuroforaminal height, segmental lumbar lordosis, total lumbar lordosis, incidence of endplate fracture, and subsidence were measured. Perioperative parameters were also recorded in each group. Clinical outcome in both groups was assessed by the short form-12, Oswestry disability index and visual analogue scale scores. The average follow-up period was 16.1 months in the LLIF group and 21 months in the PLIF group.ResultsThe restoration of disc height, foraminal height, and segmental lumbar lordosis was significantly better in the LLIF group (p<0.001). The duration of the operation was similar in both groups, but the average blood loss was significantly lower in the LLIF group (p<0.001). However, clinical outcome scores were similar in both groups.ConclusionsSafe, effective interbody fusion can be achieved at multiple levels with neuromonitoring by the lateral approach. LLIF is a viable treatment option in patients with new onset symptoms due to degenerative spondylolisthesis who have had previous lumbar spine surgery, and it results in improved sagittal alignment and indirect foraminal decompression

Multivariate Analysis on Risk Factors for Postoperative Ileus After Lateral Lumbar Interbody Fusion

Study Design. Retrospective cohort study. Objective. To assess for independent risk factors of postoperative ileus (POI) after lateral lumbar interbody fusion (LLIF). Summary of Background Data. POI is frequently observed in anterior lumbar interbody fusion due to significant bowel manipulation during the approach. LLIF is a minimally invasive approach to the anterior column with reduced bowel manipulation and surgical time. However, there is a paucity of literature on POI after LLIF. Methods. A retrospective review was performed of records of patients who underwent LLIF from January 2006 to December 2011 at a single institution. Patients with prolonged and recurrent POI were identified by review of hospital stay documentation by a fellowship-trained spine surgeon and a research fellow. POI patients were matched 1: 1 to a control cohort without POI. Uni- and multivariate analyses were performed on demographic, comorbidity, surgical indication, medication, and perioperative details to identify independent risk factors for POI. Results. Incidence of prolonged or recurrent POI after LLIF was 7.0% (42/ 596). Postoperative length of stay was significantly higher for patients with POI (9.9 +/- 4.3 d) than control patients (5.6 +/- 4.1 d) (P < 0.001). The incidence of ileus in the first 100 LLIF cases (11%) was not significantly higher than in the last 100 LLIF cases (6%) (P = 0.21). Independent risk factors were history of gastroesophageal reflux disease (P < 0.01, adjusted odds ratio [aOR]: 24.31), posterior instrumentation (P - 0.002, aOR: 19.48), and LLIF at L1-L2 (P = 0.04, aOR: 7.82). A history of prior abdominal surgery approached significance as an independent protective factor (P = 0.07, aOR: 0.29). Conclusion. There was a relatively high incidence of POI after LLIF. Independent risk factors for POI were a history of gastroesophageal reflux disease, posterior instrumentation, and LLIF at L1- L2. A history of prior abdominal surgery approached significance as an independent protective factor

A Prospective Analysis of Skin and Fingertip Advanced Glycation End-Product Devices in Healthy Volunteers

Background: Advanced glycation end products (AGEs) have been shown to accumulate in bone and are gaining interest in connective tissue research. Aims: To investigate the intrarater reliability, two-timepoint agreement and correlations within and between two commercially available skin autofluorescence (SAF) AGE devices. Methods: Healthy volunteers were enrolled in a prospective study at a single academic institution. Each participant underwent SAF analysis by two different, commercially available devices on two occasions, 14 days apart. Upon enrollment, a general survey about the participant&rsquo;s lifestyle and health status was completed and followed up on for any changes at timepoint two. Results: In total, 40 participants (F:M ratio 5:3) with an average age of 39.0 &plusmn; 12.5 years were analyzed. For the AGE reader (skin) and AGE sensor (fingertip), both intrarater reliability and two-timepoint agreement were excellent with an interclass correlation coefficient (ICC) &gt; 0.90 and a strong correlation within both machines. However, there was no correlation between both machines for either timepoint. In total, 4 participants were identified as outliers above the +2SD. Additionally, 5 participants with dark-colored skin could not be measured with the AGE reader at timepoint one and 4 at timepoint two. In contrast, all participants were able to undergo SAF analysis with the AGE sensor, irrespective of their skin type. Conclusions: Both machines showed excellent intrarater reliability and two-timepoint agreement, but the skin AGE reader might have limited applicability in individuals with dark-colored skin. Future research on AGEs might take our findings into consideration

Prevalence of Occult Infections in Posterior Instrumented Spinal Fusion

STUDY DESIGN: This is a prospective observational study. OBJECTIVE: The aim of this study is to determine the rate of occult infection after instrumented spine surgery in presumed aseptic patients. SUMMARY OF BACKGROUND DATA: The reported incidence rate of delayed/occult infection determined by positive culture swabs after instrumented spine surgery in prospective studies is 0.2%-6.9%. However, this rate may be higher as delayed infections are challenging to diagnose. Fever can be absent and inflammatory markers are often normal. If indolent organisms exist in low concentrations surrounding the instrumentation, these organisms can possibly avoid detection and disrupt bone formation leading to instrumentation loosening, pain generation, and/or failure of a solid fusion. MATERIALS AND METHODS: This study included 50 consecutive presumed aseptic patients undergoing a posterior revision requiring removal of instrumentation at least 6 months following their index procedure. Common markers of infection were examined preoperatively. Multiple culture swabs were taken directly from the removed instrumentation and cultured for 14 days. RESULTS: Of the 50 patients, 19 (38%) were culture-positive (CP) for bacteria upon removal of their instrumentation, with 14 patients (28%) having ≥2 positive specimens of the same organism. The average length of time between the index procedure and the revision surgery was 4.55 years (range: 0.53-21 y). Polymicrobial infections were found in 26% (5/19) of CP patients. The most prevalent microorganism found was Propionibacterium acnes, in 63% (12/19) of CP patients. There was no significant difference between CP and culture-negative patients regarding preoperative markers for infection, age, or length between index and revision procedures. CONCLUSIONS: The results of this study indicate a positive culture rate of 38% in presumed aseptic patients who had previously undergone instrumented spine surgery. These results are consistent with other retrospective studies and are \u3e6 times greater than any previous prospective study utilizing culture swabs. LEVEL OF EVIDENCE: Level-III

Correlation between Urine N-Terminal Telopeptide and Fourier Transform Infrared Spectroscopy Parameters: A Preliminary Study

N-terminal telopeptide (NTX) is a bone resorption marker that is commonly referenced in clinical practice. Bone remodeling is also associated with changes in mineral components. Fourier transform infrared spectroscopy (FTIR) is utilized in the assessment of bone material properties and some parameters are reported to have associations with bone remodeling. The aim of this cross-sectional study is to investigate the relationship between uNTX levels and FTIR parameters, utilizing prospectively collected study data for patients who underwent lumbar fusion surgery. Bone specimens were taken from iliac crest (IC) and vertebrae (V). Cortical (C) and trabecular (T) bones were separately analyzed. 22 patients (mean age 60.0 years (35.9–73.3), male : female 9 : 13) were included in the final analysis. Women showed significantly higher uNTX levels (male : female, median [range] 21.0 [11.0–39.0] : 36.0 [15.0–74.0] nM·BCE/mM, p=0.033). Among women, a significant positive correlation was observed between uNTX and mineral-to-matrix ratio in IC-C. Among men, uNTX demonstrated significant negative correlation with collagen crosslinks (XLR: ratio of mature to immature collagen crosslinks) in IC-C, V-T, and V-C. In addition, uNTX was positively correlated with acid phosphate substitution (HPO4, a parameter of new bone formation) in IC-C, IC-T, and V-C. After age adjustment, HPO4 in IC-T and V-C among men showed significant positive associations with uNTX (IC-T: p=0.018, R2 = 0.544; V-C: p=0.007, R2 = 0.672). We found associations between FTIR parameters and uNTX in men, but not in women. The correlations between uNTX and FTIR parameters in men might suggest a better balance of bone breakdown (uNTX) and new bone formation (FTIR parameters: XLR, HPO4) than in women

Fat infiltration of the posterior paraspinal muscles is inversely associated with the fat infiltration of the psoas muscle: a potential compensatory mechanism in the lumbar spine

Abstract Background The function of the paraspinal muscles and especially the psoas muscle in maintaining an upright posture is not fully understood. While usually considered solely as a hip flexor, the psoas muscle and its complex anatomy suggest that the muscle has other functions involved in stabilizing the lumbar spine. The aim of this study is to determine how the psoas muscle and the posterior paraspinal muscles (PPM; erector spinae and multifidus) interact with each other. Methods A retrospective review including patients undergoing posterior lumbar fusion surgery between 2014 and 2021 at a tertiary care center was conducted. Patients with a preoperative lumbar magnetic resonance imaging (MRI) scan performed within 12 months prior to surgery were considered eligible. Exclusion criteria included previous spinal surgery at any level, lumbar scoliosis with a Cobb Angle > 20° and patients with incompatible MRIs. MRI-based quantitative assessments of the cross-sectional area (CSA), the functional cross-sectional area (fCSA) and the fat area (FAT) at L4 was conducted. The degree of fat infiltration (FI) was further calculated. FI thresholds for FIPPM were defined according to literature and patients were divided into two groups (< or ≥ 50% FIPPM). Results One hundred ninetypatients (57.9% female) with a median age of 64.7 years and median BMI of 28.3 kg/m2 met the inclusion criteria and were analyzed. Patients with a FIPPM ≥ 50% had a significantly lower FI in the psoas muscle in both sexes. Furthermore, a significant inverse correlation was evident between FIPPM and FIPsoas for both sexes. A significant positive correlation between FATPPM and fCSAPsoas was also found for both sexes. No significant differences were found for both sexes in both FIPPM groups. Conclusion As the FIPPM increases, the FIPsoas decreases. Increased FI is a surrogate marker for a decrease in muscular strength. Since the psoas and the PPM both segmentally stabilize the lumbar spine, these results may be indicative of a potential compensatory mechanism. Due to the weakened PPM, the psoas may compensate for a loss in strength in order to stabilize the spine segmentally