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Retrospective cohort study.Compare rates of postoperative neural deficits between surgical approaches for thoracic disc herniations (TDHs).Anterior and posterior approaches for TDH carry high reported neurological risk, albeit comparative risk is not well defined.Health Care Utilization Project (HCUP) state inpatient databases (NY, FL, CA; 2005-2014) were queried for patients who underwent TDH operation. Demographics, operative details, surgical approach, neural injury, length of stay (LOS), and discharge location were assessed. Multivariate linear regression was used to determine relative risk of neural deficit and skilled nursing facility (SNF) discharge.Six hundred ninety-seven patients (mean age 52.0 yrs, 194 institutions) met inclusion. Majority of operations were elective (76.0%) and one to two levels (80.5%). Overall neural injury rate was 9.0%. Anterior operations had significantly lower rates of neural injury compared with posterior operations on univariate analysis (4.6% vs. 11.4%; P 0.01). All multilevel operations had similarly high rates of neural injury. On multivariate analysis, posterior approaches (RR 1.78; P = 0.12) and combined approaches (RR 2.15; P = 0.17) had higher neural risk compared with anterior approaches after controlling for younger age, higher Charlson Comorbidity Index, and nonelective admissions. Combined approaches had similar neural injury rates (13.8%) to posterior operations (11.4%) and significantly longer LOS and SNF discharges compared with single approaches. Neural deficit was associated with discharge to SNF (With = 87.3%; Without = 23.7%; P 0.01) and increased LOS (With = 12.5 days; Without = 6.9 days; P 0.01).Overall rate of neural deficit after operation for TDH was 9.0%. While anterior approach was associated with a lower neural injury rate, this association was confounded by age, Charlson Comorbidity Index, and admission type. After correcting for these confounders, a nonsignificant trend remained that favored the anterior approach. Neural deficit was associated with increased LOS and discharge to SNF postoperatively.Level of Evidence: 4.

STUDY DESIGN An ex vivo study of the rabbit's vertebral endplate. OBJECTIVE The aim of this study was to assess the effect of axial compression and distraction on vascular buds and vascular endothelial growth factor (VEGFA) expression of the vertebral endplate (VEP). SUMMARY OF BACKGROUND DATA The abnormal load can lead to intervertebral disc degeneration (IDD), whereas axial distraction can delay this process. The effects of different mechanical loads on the intervertebral disc (IVD) have been hypothesized to be related to changes in the vascular buds of the VEP; moreover, the process that might involve the vascular endothelial growth factor (VEGF) within the VEP. METHODS Rabbit spinal segments (n = 40) were harvested and randomly classified into four groups: Control group, no stress was applied; Group A, a constant compressive load applied; Group B, compression load removed for a fixed time daily on a continuous basis, and substituted with a distraction load for 30 minutes; and Group C, compression removed for 30 minutes for a fixed period daily on a continuous basis. Tissue specimens were collected before the culture (day 0) and on day 14 post-culture of each group for analysis of IVDs' morphology, and protein and mRNA expression of Aggrecan, COL2al, VEGFA, and vascular endothelial growth factor receptor 2 of the VEPs. RESULTS Application of axial distraction and dynamic load compression significantly delayed time- and constant compression-mediated VEP changes and IDD. Moreover, the degree of degeneration was associated with loss of vascular buds, as well as the downregulation of VEGFA and its receptor. CONCLUSION The regulation of vascular buds and VEGF expression in the VEP represents one of the mechanisms of axial distraction and dynamic loading.Level of Evidence: N/A.

Study design Retrospective cohort. Objective To determine surgery-free survival of patients receiving conservative management of lumbar disc herniation (LDH) in the military healthcare system (MHS) and risk factors for surgical intervention. Summary of background data Radiculopathy from LDH is a major cause of morbidity and cost. Methods The Military Data Repository was queried for all patients diagnosed with LDH from FY2011-2018; the earliest such diagnosis in a military treatment facility (MTF) was kept for each patient as the initial diagnosis. Follow-up time to surgical intervention was defined as the time from diagnosis to first encounter for lumbar microdiscectomy or lumbar decompression in either a MTF or in the civilian sector. The Military Data Repository was also queried for history of tobacco use at any time during MHS care, age at the time of diagnosis, sex, MHS beneficiary category, and diagnosing facility characteristics. Multivariable Cox proportional hazards models were used to evaluate the associations of patient and diagnosing facility characteristics with time to surgical intervention. Results A total of 84,985 MHS beneficiaries including 62,771 active duty service members were diagnosed with LDH in a MTF during the 8-year study period. A total of 10,532 (12.4%) MHS beneficiaries, including 7650 (10.9%) active duty, failed conservative management onto surgical intervention with lumbar microdiscectomy or lumbar decompression. Median follow-up time of the cohort was 5.2 (interquartile range 2.6, 7.5) years. Among all healthcare beneficiaries, several patient-level (younger age, male sex, and history of tobacco use) and facility-level characteristics (hospital vs. clinic and surgical care vs. primary care clinic) were independently associated with higher risk of surgical intervention. Conclusion LDH compromises military readiness and negatively impacts healthcare costs. MHS beneficiaries with LDH have a good prognosis with approximately 88% of patients successfully completing conservative management. However, strategies to improve outcomes of conservative management in LDH should address risks associated with both patient and facility characteristics.Level of Evidence: 4.

Study design Retrospective register study. Objective The aim of this study was to assess the incidence and trends of lumbar disc surgeries in Finland from 1997 through 2018. Summary of background data The evidence on lumbar spine discectomy has shifted from supporting surgical treatment toward nonoperative treatment. Still, the incidence of lumbar discectomy operations increased until the 1990 s. In the United States, the incidence began to decline after a downward turn in 2008, yet recent trends from countries with public and practically free health care are not widely known. Methods Data for this study were obtained from the Finnish nationwide National Hospital Discharge Register. The study population covered all patients 18 years of age or older in Finland during a 22-year period from January 1, 1997, to December 31, 2018. Results A total of 65,912 lumbar discectomy operations were performed in Finland from 1997 through 2018. The annual population-based incidence of lumbar discectomy decreased 29% during the 22-year period, from 83 per 100,000 person-years in 1997 to 58 per 100,000 person-years in 2018. In addition, the incidence of microdiscectomy increased 12%, from 41 per 100,000 person-years in 1997 to 47 per 100,000 person-years in 2018, whereas the incidence of open discectomy decreased 71%, from 41 per 100,000 person-years in 1997 to 12 per 100,000 person-years in 2018. The total reoperation rate for microendoscopic, microscopic, and open discectomy surgeries was 16.3%, 15.3%, and 14.9%, respectively. Conclusion The nationwide incidence of lumbar discectomy decreased in Finland from 1997 through 2018. Additionally, the incidence of open discectomy is decreasing rapidly, whereas the incidence of microsurgical techniques is increasing.Level of Evidence: 3.

Study design An experimental animal study. Objective The aim of this study was to investigate the effect of pulsed electromagnetic fields (PEMF) on recovery of sensorimotor function in a rodent model of disc herniation (DH). Summary of background data Radiculopathy associated with DH is mediated by proinflammatory cytokines. Although we have demonstrated the anti-inflammatory effects of PEMF on various tissues, we have not investigated the potential therapeutic effect of PEMF on radiculopathy resulting from DH. Methods Nineteen rats were divided into three groups: positive control (PC; left L4 nerve ligation) (n = 6), DH alone (DH; exposure of left L4 dorsal root ganglion [DRG] to harvested nucleus pulposus and DRG displacement) (n = 6), and DH + PEMF (n = 7). Rodents from the DH + PEMF group were exposed to PEMF immediately postoperatively and for 3 hours/day until the end of the study. Sensory function was assessed via paw withdrawal thresholds to non-noxious stimuli preoperatively and 1 and 3 days postoperatively, and every 7 days thereafter until 7 weeks after surgery. Motor function was assessed via DigiGait treadmill analysis preoperatively and weekly starting 7 days following surgery until 7 weeks following surgery. Results All groups demonstrated marked increases in the left hindlimb response threshold postoperatively. However, 1 week following surgery, there was a significant effect of condition on left hindlimb withdrawal thresholds (one-way analysis of variance: F = 3.82, df = 2, P = 0.044) where a more rapid recovery to baseline threshold was evident for DH + PEMF compared to PC and DH alone. All groups demonstrated gait disturbance postoperatively. However, DH + PEMF rodents were able to regain baseline gait speeds before DH and PC rodents. When comparing gait parameters, DH + PEMF showed consistently less impairment postoperatively suggesting that PEMF treatment was associated with less severe gait disturbance. Conclusion These data demonstrate that PEMF accelerates sensorimotor recovery in a rodent model of DH, suggesting that PEMF may be reasonable to evaluate for the clinical management of patients with herniation-associated radiculopathy.Level of Evidence: N/A.

Study design A cross-sectional study of the Northern Finland Birth Cohort 1966 (NFBC1966). Objective The aim of this study was to evaluate the association between the type, size, and location of lumbar Modic changes (MC), and prolonged disabling low back pain (LBP). Summary of background data LBP is the leading cause of disability worldwide and it affects all age- and socioeconomical groups. Only a small proportion of LBP patients are diagnosed with a specific cause: In most cases no single nociceptive cause for the pain can be identified. MC are visualized in magnetic resonance imaging (MRI) as a signal intensity change in vertebral bone marrow and have been proposed to represent a specific degenerative imaging phenotype associated with LBP. MC can be classified into several subtypes, of which inflammatory Type 1 (MC1) is suggested as being more likely to be associated with LBP. Methods We assessed lumbar MRI (n = 1512) for the presence, type, and size of MC. The associations of MC characteristics with prolonged (≥30 days during the past year) and disabling (bothersomeness of LBP at least 6 on a 0-10 Numeric Rating Scale) LBP, evaluated at the time of imaging at 47 years, were analyzed using binary logistic regression, adjusted for sex, BMI, smoking, educational status, lumbar disc degeneration, and disc herniations. Results Any MC and MC1 were associated with prolonged disabling LBP (odds ratio [OR] after full adjustments 1.50 [95% confidence interval, CI 1.05-2.15] and 1.50 [95% CI 1.10-2.05], respectively). Furthermore, MC covering the whole anterior-posterior direction or the whole endplate, as well as the height of MC, were significantly associated with prolonged disabling LBP (OR after full adjustments 1.59 [95% CI 1.14-2.20], 1.67 [95% CI 1.13-2.46] and 1.26 [95% CI 1.13-1.42], respectively). Conclusion Our study showed a significant and independent association between MC and clinically relevant LBP. Level of evidence 3.

A prospective cross-sectional study.To evaluate the prevalence of sacroiliac joint dysfunction in patients with lumbar disc hernia and examine the variations in clinical parameters cause by this combination.Although one of the many agents leading to lumbar pain is sacroiliac dysfunction, little progress has still been made to evaluate mechanical pain from sacroiliac joint dysfunction within the context of differential diagnosis of lumbar pain.Two hundred thirty-four patients already diagnosed with lumbar disc hernia were included in the study. During the evaluation, sacroiliac joint dysfunction was investigated using specific tests, pain levels with a Visual Analog Scale, and the presence of neuropathic pain using Leeds Assessment of Neuropathic Symptoms and Signs Pain Scale. Other clinical assessments were performed using the Beck Depression Inventory, Health Assessment Questionnaire, and Tampa Kinesiophobia Scale.63.2% of patients were female and 36.8% were male. Mean age was 46.72 ± 11.14 years. The level of sacroiliac joint dysfunction was 33.3% in the research population. In terms of sex distribution, the proportion of women was higher in the group with sacroiliac joint dysfunction (P 0.05). No significant difference was observed in pain intensity assessed using a Visual Pain Scale between the groups (P 0.05), but the level of neuropathic pain was significantly higher in the group with dysfunction (P 0.05). In the group with sacroiliac joint dysfunction, the presence of depression was significantly higher (P = 0.009), functional capacity was worse (P 0.001), and the presence of kinesophobia was higher (P = 0.02).Our study results will be useful in attracting the attention of clinicians away from the intervertebral disc to the sacroiliac joint in order to avoid unnecessary and aggressive treatments.2.

It is a controversial issue that the difference of the occurrence of heterotopic ossification (HO) concerning cervical prosthesis is still huge. In this study, in the two cervical disc prostheses the development of HO is independent on their architecture., Study Design. Retrospective analysis using data from randomized clinical trials. Objective. To compare the occurrence of heterotopic ossification (HO) between two cervical disc prostheses. Clinical outcome and range of motion (ROM) were also evaluated. Summary of Background Data. Cervical arthroplasty was reported to be able to maintain the segmental ROM. However, controversy exists since the difference of the occurrence of HO concerning cervical prosthesis is still huge. Methods. Patients who underwent anterior cervical discectomy with arthroplasty for a cervical radiculopathy due to a herniated disc from the The Netherlands Cervical Kinematics (NECK) trial (activC; metal endplates with a polyethylene inlay and a keel for primary stability) and the PROCON trial (Bryan; metal-on-polymer with titanium coated endplates without a keel) were analyzed for HO at 12 and 24 months postoperatively. HO was scored according to the McAfee–Mehren classification. Segmental ROM was defined by a custom developed image analysis tool, and global cervical ROM was measured by Cobb's angle. Clinical outcome was evaluated by means of the neck disability index (NDI) as well as physical-component summary (PCS) and mental-component summary (MCS). Results. At 2-year follow-up, the occurrence of HO was 68% in patients treated with the activC prosthesis (severe HO 55%), which was comparable with 85% (P = 0.12) in patients with the Bryan disc (severe HO 44%; P = 0.43). The HO progression was similar between groups. Clinically, the patients had comparable NDI, PCS, and MCS at 2-year follow-up, and comparable improvement of clinical outcomes. The global ROM in the Bryan group (56.4 ± 10.8°) was significantly higher than in the activC group (49.5 ± 14.0, P = 0.044) at 2-year follow-up. Conclusion. In comparison of two cervical disc prostheses the development of HO is independent on their architecture. Although global ROM was higher in the Bryan prosthesis group, this difference was not deemed clinically important, particularly because the clinical condition of patients with and without severe HO was comparable. Level of Evidence: 2

STUDY DESIGN Prospective cohort study. OBJECTIVE The aims of this study were to evaluate the outcome of surgical and nonsurgical treatment for patients with lumbar herniated disc (LHD) or lumbar spinal stenosis (LSS) after 2 years and to identify predictors for nonsuccess. SUMMARY OF BACKGROUND DATA Studies regarding the clinician's ability to identify patients with a poor prognosis are not in concurrence and further studies are warranted. METHODS This study included 390 patients with LHD or LSS referred for surgical evaluation after unsuccessful conservative treatment. Nonsuccess was defined as a Roland-Morris Disability score above 4 (0-23) or a Numeric Rating Scale back and leg pain score above 20 (0-60). Uni- and multivariate logistic regression analyses were used to investigate potential predictive factors including sociodemographic characteristics, history findings, levels of pain and disability, and magnetic resonance imaging findings. RESULTS Rates of nonsuccess at 2 years were approximately 30% in surgically treated patients with LHD, approximately about 60% in patients with LSS for disability, and 30% and 40%, respectively for pain. For the main outcome variable, disability, in the final multiple logistic regression model, nonsuccess after surgery was associated with male sex (odds ratio [OR] 2.04, 95% confidence interval [CI]: 1.02-4.11, P = 0.04), low level of education (OR 2.60, 95% CI: 1.28-5.29, P = 0.01), high pain intensity (OR 3.06, 95% CI: 1.51-6.21, P

STUDY DESIGN A biomechanical analysis correlating internal disc strains and tissue damage during simulated repetitive lifting. OBJECTIVE To understand the failure modes during simulated safe and unsafe repetitive lifting. SUMMARY OF BACKGROUND DATA Repetitive lifting has been shown to lead to lumbar disc herniation (LDH). In vitro studies have developed a qualitative understanding of the effect of repetitive loading on LDH. However, no studies have measured internal disc strains and subsequently correlated these with disc damage. METHODS Thirty human cadaver lumbar functional spinal units were subjected to an equivalent of 1 year of simulated repetitive lifting under safe and unsafe levels of compression, in combination with flexion (13-15°), and right axial rotation (2°) for 20,000 cycles or until failure. Safe or unsafe lifting were applied as a compressive load to mimic holding a 20 kg weight either close to, or at arm's length, from the body, respectively. Maximum shear strains (MSS) were measured, and disc damage scores were determined in nine regions from axial post-test magnetic resonance imaging (MRI) and macroscopic images. RESULTS Twenty percent of specimens in the safe lifting group failed before 20,000 cycles due to endplate failure, compared with 67% in the unsafe group. Over half of the specimens in the safe lifting group failed via either disc protrusion or LDH, compared with only 20% via protrusion in the unsafe group. Significant positive correlations were found between MRI and macroscopic damage scores in all regions (rs > 0.385, P

MINI: We summarized the 10-year outcomes of Spine Patient Outcomes Research Trial for intervertebral disc herniation through a systematic review. The observational cohort 2-year analysis and the as-treated analysis of the randomized control trial at 4 and 8 years showed statistically greater improvements in those patients who were treated surgically.We performed a comprehensive search of Pubmed, MEDLINE, and EMBASE for English-language studies of all levels of evidence pertaining to SPORT, in accordance with Preferred Reported Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines.We aim to summarize the 10-year clinical outcomes of SPORT and its numerous follow-up studies for intervertebral disc herniation.The Spine Patient Outcomes Research Trial (SPORT) was a landmark study. SPORT compared surgical and nonoperative management of the three most common spinal pathologies.Keywords utilized included: SPORT, spine patient outcomes research trial, disc herniation, and surgical outcomes.The observational cohort analysis revealed statically greater improvement in primary outcomes at 3 months and 2 years in patients who had surgery, while analysis of the randomized control trial cohort failed to show a significant difference based on the intent-to-treat principle due to significant patient crossover. However, 4 year and 8 year as-treated analysis showed statistically greater improvements in those patients who were treated surgically. SPORT's subgroup analysis evaluated important factors when considering the treatment of IDH, including patient characteristics, level of herniation, duration of symptoms, recurrence of pain, presence of retrolistheiss, patient functional status, effects of previous treatment with epidural steroid injections and opioid medication, outcomes after incidental durotomy, MRI reader reliability, reoperation rates, and risk factors for reoperation. The clinical impact of SPORT was also investigated and included comparison of SPORT patients to NSQIP patients to determine generalizability, outcome differences in SPORT's surgical center sites, patient preferences, patient expectations, level of education, and effects of watching an evidence-based video.Ten years after its inception, SPORT has made strides in standardization and optimization of treatment for spinal pathologies. SPORT has provided clinicians with insight about outcomes of surgical and nonoperative treatment of IDH. Results showed significantly greater improvements in patients treated surgically.3.We performed a comprehensive search of Pubmed, MEDLINE, and EMBASE for English-language studies of all levels of evidence pertaining to SPORT, in accordance with Preferred Reported Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. We aim to summarize the 10-year clinical outcomes of SPORT and its numerous follow-up studies for intervertebral disc herniation. The Spine Patient Outcomes Research Trial (SPORT) was a landmark study. SPORT compared surgical and nonoperative management of the three most common spinal pathologies. Keywords utilized included: SPORT, spine patient outcomes research trial, disc herniation, and surgical outcomes. The observational cohort analysis revealed statically greater improvement in primary outcomes at 3 months and 2 years in patients who had surgery, while analysis of the randomized control trial cohort failed to show a significant difference based on the intent-to-treat principle due to significant patient crossover. However, 4 year and 8 year as-treated analysis showed statistically greater improvements in those patients who were treated surgically. SPORT's subgroup analysis evaluated important factors when considering the treatment of IDH, including patient characteristics, level of herniation, duration of symptoms, recurrence of pain, presence of retrolistheiss, patient functional status, effects of previous treatment with epidural steroid injections and opioid medication, outcomes after incidental durotomy, MRI reader reliability, reoperation rates, and risk factors for reoperation. The clinical impact of SPORT was also investigated and included comparison of SPORT patients to NSQIP patients to determine generalizability, outcome differences in SPORT's surgical center sites, patient preferences, patient expectations, level of education, and effects of watching an evidence-based video. Ten years after its inception, SPORT has made strides in standardization and optimization of treatment for spinal pathologies. SPORT has provided clinicians with insight about outcomes of surgical and nonoperative treatment of IDH. Results showed significantly greater improvements in patients treated surgically. Level of Evidence: 3.

Study design Retrospective study of prospectively collected outcome data. Objective The aim of this study was to investigate reoperation cases and determine whether or not the experience period of a single surgeon was associated with the causes of reoperations following lumbar microendoscopic discectomy for disc herniation (MEDH) and microendoscopic decompression for spinal stenosis (MEDS). Summary of background data There have been few studies that investigated reoperation cases following MEDH and MEDS. Methods Between June 2005 (first experience of MEDH) and September 2013, the same surgeon had been using MEDH and/or MEDS on 441 consecutive patients. The follow-up rate was 89.3%. The causes and rates of reoperations (RORs) were determined at 5 years after the initial operations. We also investigated the experience period of a single surgeon (EPS, interval between June 2005 and initial operation: median, 37 months). Results The 5-year reoperation rate for all patients combined was 12.4% (49/394). The main causes for reoperations were recurrence of disc herniation (ROR, 7.01%) and increase of postoperative spondylolisthesis and/or instability (ROR, 9/394 = 2.28%); two of the nine cases were caused by excessive decompression, and the EPSs were 11 and 16 months. The other causes for reoperations were postoperative epidural hematoma (ROR, 0.76%; median EPS, 20 months), insufficient decompression (ROR, 0.25%; EPS, 17 months), and residual segmental scoliosis (ROR, 7.69%); two segmental scoliosis cases did not provide relief from sciatica, and therefore L4/5 transforaminal interbody fusions were performed. Conclusion Postoperative epidural hematoma and excessive or insufficient decompression were often observed in the initial series of patients as the causes for reoperations. We think that it is important to be aware of and prevent such potential problems in any initial series of patients, as there are limitations to any surgical indications for the use of microendoscopic decompression for degenerative segmental scoliosis because of original traction and/or kinking of nerve roots. Level of evidence 4.

Controlled, randomized, animal study.To investigate the effect of melatonin and its receptors on radicular pain and the possible mechanisms.Lumbar disc herniation (LDH) may induce radicular pain, but the mechanism is not clear and therapeutic effect is still poor. Previously we report central sensitization meaning potentiation of spinal nociceptive synaptic transmission is the critical cause of radicular pain. Melatonin (Mel) has been reported to promote hippocampal synaptic transmission and thus improve learning ability. But the effect of Mel on spinal synaptic transmission and radicular pain are not clear.Rat LDH model was induced by autologous nucleus pulposus (NP) implantation. Melatonin was delivered intraperitoneally four times a day, from day 1 to day 3 after surgery. Melatonin receptor agonist and antagonists were delivered intrathecally for 3 days as well. Mechanical and thermal pain thresholds were assessed by von Frey filaments and hotplate test respectively. Electrophysiological recording was employed for survey C-fiber evoked field potentials. The protein level of N- methyl-D-aspartate submit 2A (NR2A), NR2B, melatonin receptor 1 (MT1), and receptor 2 (MT2) was evaluated by western blotting. Spinal expression of calcitonin gene related peptides (CGRP), isolectin b4 (IB4), and neurofilament-200 (NF200) was displayed by immunofluorescence staining.Melatonin significantly increased mechanical and thermal pain thresholds, lasting at least to day 5 after surgery. Melatonin decreased C-fiber evoked field potentials; decreased spinal NR2B protein level; reduced spinal CGRP, and IB4 expression. MT2 was upregulated after NP implantation and was co-localized with neuron and microglia. MT2 receptor agonist simulated the effect of Mel, and both MT receptor broadspectrum antagonist and MT2 specific antagonist abolished the effect of MT2 receptor agonist.Melatonin alleviates radicular pain from LDH by inhibiting central sensitization via binding with its receptor 2, decreasing spinal CGRP, IB4, and NR2B expression.

An algorithm was developed with MATLAB platform to automatically quantify the volume of cervical disc herniation (CDH) based on the sagittal magnetic resonance images. This automated program was used for CDH data set, and then compared with manual measurement results confirming its reliability.The aim was to develop a new software for automated CDH volume measurement.CDH compresses the spinal cord, regarding as the leading cause of cervical myelopathy. However, the CDH volume, of great value to clinical symptoms, can be only manually measured with no-excellent but acceptable interobserver reliability. This was due to the manual error of outlining CDH area and inclusion of structure posterior vertebra. No studies has proposed such an automated algorithm of CDH volume quantification which is standardised to quantify the accurate volume of CDH thus helping doctors easily evaluate CDH progressing.The algorithm of CDH volume measurement was proposed. This program was then tested for 490 CDHs data set, from 185 patients with two repeated magnetic resonance imaging detections. Three individual observers manually measured the volumes of these CDHs, to justify the accuracy of this software. CDH volume was either in the classic way or the revised way excluding the influence of structure posterior vertebra.The automated software was successfully developed on MATLAB platform, with no difference found with manual measurements (average level) in CDH volume measurement. The change ratios in CDH volumes were profoundly consistent with manual observation, showing the error of 5.8% in median. The revised method elevated the absolute value of ratio by amplifying the percentage change.Our developed automated volumetry system was an standardized and accurate way, with selective removal module of structure posterior vertebra, replaceable for manual volume measurement of CDH, which was useful for spinal surgeons diagnosing and treating CDH disease.

Study design Retrospective study on 185 patients with 490 cervical disc herniation (CDH). Objective To compare the changes in volumes of CDH in patients with degenerative cervical myelopathy (DCM) surgically-treated by expansive open-door laminoplasty (EOLP) or cervical microendoscopic laminoplasty (CMEL). Summary of background data Spontaneous resorption of CDH was shown in patients with DCM after conservation treatment, but very few in surgically-treated patients. Our previous study identified the clinical efficiency of CMEL to treat DCM but how CDH sized postoperatively, as well as comparing to EOLP, was unknown. Methods Consecutive patients with DCM from Dec 2015 to Dec 2019, who underwent MRI evaluation, receiving CMEL or EOLP, and repeat MRI in follow-up were included. The volume of CDH were monitored using the picture archiving and communication system, further calculating the incidence of CDH with volume regression and the percentage changes of CDH volume. The correlations of possible determines with CDH volume changes were analyzed by Spearman rank correlation coefficient. Results A total of 89 patients (215 CDHs, EOLP-group) and 96 patients (275 CDHs, CMEL-group) was surveyed respectively. Resultantly, volume of CDH was decreased post-operatively in both EOLP and CMEL cases. But this CDH volume regression was more profound in CMEL groups (incidence of 81.2% from 223/275, median volume change ratio of -26.7%, occurring from one month after CMEL), statistically different from EOLP group (50.2% from 108/215, median volume change ratio of -5.4%, none-appearance within one month). Patients information as gender, age and follow-up time, not CDH significant, was significantly correlated with CDH volume changes. Conclusion Patients who underwent CMEL developed a postoperative reduction of CDH volume, with more popularity, greater degree and earlier-staged than EOLP-patients. Young females with longer follow-up time were more likely occur.Level of Evidence: 4.

Retrospective cohort study.The purpose of this investigation was to evaluate the regional variations in the use of nonoperative therapies in patients diagnosed with a lumbar intervertebral disc herniation 3 months prior to undergoing microdiscectomy surgery.Regional variations in the management of chronic pain conditions have been previously identified. Patients suffering from a lumbar intervertebral disc herniation are typically treated with a brief course of conservative management prior to attempting microdiscectomy surgery. Whether regional differences exist in the utilization or costs of maximum nonoperative therapy (MNT) remains unknown.Medical records from patients diagnosed with a lumbar intervertebral disc herniation undergoing 1, 2, or 3-level index microdiscectomy operations between 2007 and 2017 were gathered from the HORTHO insurance database consisting of private/commercially insured and Medicare Advantage beneficiaries. Patient regional designation was divided into Midwest, Northeast, South, and West territories and was derived from the insurance claim location. The utilization of MNT within 3 months after initial lumbar herniation diagnosis in adult patients was analyzed.Our population consisted of 13,106 patients who underwent primary index microdiscectomy surgery. Significant regional variation was identified in the nonoperative therapy failure rate (P0.0001), with the highest proportion of Midwest patients failing (2.7%). There were statistical differences in the regional distribution of patients utilizing NSAIDs (P0.0001), muscle relaxants (P0.0001), lumbar epidural steroid injections (P0.0001), physical therapy and occupational therapy sessions (P0.0001), chiropractor treatments (P0.0001), and emergency department services (P = 0.0049). The total direct cost associated with all MNT prior to microdiscectomy was $13,205,924, with 59.6% from the South, 31.1% from the Midwest, 8.3% from the West, and 1.1% from the Northeast.These findings indicate that regional differences exist in the utilization and costs of MNT of a lumbar intervertebral herniated disc prior to microdiscectomy surgery.3.

Study design Case series and review of literature. Objective To report three cases of vascular injury during posterior lumbar disc surgery, two of these occurred during open discectomy, and one during an endoscopic surgery. Aim is to highlight importance of early diagnosis and prompt steps taken to prevent morbidity and mortality. Summary of background data Vascular injury during lumbar discectomy is rare injury. Also no case has been reported so far occurring during an endoscopic discectomy. Methods Three patients were treated for lumbar intervertebral disc prolapse, two had undergone open posterior discectomy while the third patient underwent endoscopic discectomy and all of them were diagnosed to have suffered an abdominal vascular injury. Results In two cases pseudo-aneurysm was found while third case was diagnosed as an arterio-venous fistula. All the three cases were managed with endovascular stenting and followed for a minimum period of 2 years. No further complications were detected. Conclusion Vascular injury during a disc surgery is difficult to diagnose due to the rarity of occurrence and subtle signs which need to be recognized to start early management. Level of evidence 5.

STUDY DESIGN A systematic review. OBJECTIVE The aim of this study was to determine the association between study outcomes and the presence of a conflict of interest (COI) in the lumbar disc arthroplasty (LDA) literature. SUMMARY OF BACKGROUND DATA Previous studies have evaluated the efficacy of LDA as a surgical alternative to arthrodesis. As investigators may have financial relationships with LDA device companies, it is important to consider the role of COI on study outcomes. METHODS A systematic review was performed to identify articles reporting clinical outcomes of LDA. Any financial COIs disclosed were recorded and confirmed through Open Payments and ProPublica databases. Study outcomes were graded as favorable, unfavorable, or equivocal. Pearson Chi-squared analysis was used to determine an association between COI and study outcomes. Favorable outcomes were tested for an association with study characteristics using Poisson regression with robust error variance. RESULTS Fifty-seven articles were included, 30 had a financial COI, while 27 did not. Ninety percent of the conflicted studies disclosed their COI in the article. Studies with United States authors were more likely to be conflicted (P = 0.019). A majority of studies reported favorable outcomes for LDA (n = 39). Conflicted studies were more likely to report favorable outcomes than nonconflicted studies (P = 0.020). Articles with COIs related to consultant fees (P = 0.003), research funding (P = 0.002), and stock ownership (P

Retrospective analysis of clinical records.The aim of this study is to evaluate the clinical outcomes and neurological complications of full-endoscopic visualized foraminoplasty and discectomy under general anesthesia for the treatment of L4-L5 and L5-S1 disc herniation.Full-endoscopic visualized foraminoplasty and discectomy, which is our newly developed technique, has been used in the treatment of lumbar disc herniation and lumbar spinal stenosis. While the clinical effect, safety, and neurological complications of full-endoscopic visualized foraminoplasty and discectomy under general anesthesia are still uncertain.Between May 2015 and April 2017, 84 patients with lumbar disc herniation were included, and categorized into L4-L5 group and L5-S1 group according to the discectomy segment. Full-endoscopic visualized foraminoplasty and discectomy was performed under general anesthesia. Operative time, fluoroscopy time, hospitalization time, and complications were recorded. Each patient included was followed for at least 12 months. Visual analog scale score for leg and back pain and Oswestry Disability Index score were evaluated preoperatively and at 3, 6, and 12 months postoperatively. The modified MacNab criteria were also used to evaluate surgical effectiveness.The mean operative time, fluoroscopy time, and hospitalization time at L4-L5 and L5-S1 were of no significant difference. The mean visual analog scale and Oswestry Disability Index postoperative scores were significantly improved over the preoperative scores. Intraoperative nerve injury occurred in one case at L4-L5, with a neurological complication rate of 2.1% in L4-L5 group. One case at L4-L5 suffered recurrence 2 weeks after the surgery, resulting in a recurrence rate of 2.1% in L4-L5 group. This recurrence case was treated by a second full-endoscopic visualized foraminoplasty and discectomy under general anesthesia.Full-endoscopic visualized foraminoplasty and discectomy under general anesthesia is efficient and safe for the treatment of L4-L5 and L5-S1 disc herniation.4.

Animal experiment: a rat model of lumbar disc herniation (LDH) induced painful radiculopathies.To investigate the role and mechanism of AMP-activated protein kinase (AMPK) in dorsal root ganglia (DRG) neurons in LDH-induced painful radiculopathies.Overactivation of multiple pain signals in DRG neurons triggered by LDH is crucial to the development of radicular pain. AMPK is recognized as a cellular energy sensor, as well as a pain sensation modulator, but its function in LDH-induced pain hypersensitivity remains largely unknown.The LDH rat model was established by autologous nucleus pulposus transplantation into the right lumbar 5 (L5) nerve root. At different time points after AMPK agonist metformin (250 mg/kg/d) or mammalian target of rapamycin (mTOR) inhibitor rapamycin (5 mg/kg) intraperitoneal administration, thermal and mechanical sensitivity were evaluated by measuring paw withdrawal latency (PWL) and 50% paw withdrawal thresholds (PWT). The levels of AMPK, mTOR, and p70S6K phosphorylation were determined by Western blot. We also investigated the proportion of p-AMPK positive neurons in the right L5 DRG neurons using immunofluorescence.LDH evoked persistent thermal hyperalgesia and mechanical allodynia on the ipsilateral paw, as indicated by the decreased PWL and 50% PWT. These pain hypersensitive behaviors were accompanied with significant inhibition of AMPK and activation of mTOR in the associated DRG neurons. Pharmacological activation of AMPK in the DRG neurons not only suppressed mTOR/p70S6K signaling, but also alleviated LDH-induced pain hypersensitive behaviors.We provide a molecular mechanism for the activation of pain signals based on AMPK-mTOR axis, as well as an intervention strategy by targeting AMPK-mTOR axis in LDH-induced painful radiculopathies.N/A.

Study design: A controlled radiologic follow-up study. Objective: The aim of this study was to ascertain whether changes in cord excursion with straight leg raise test (SLR) at 1.5-year follow- up time accompany changes in clinical symptoms. Summary of background data: Lumbar intervertebral disc herniation (LIDH) is known to be a key cause of sciatica. Previously, we found that a significant limitation of neural displacement (66.6%) was evident with the SLR on the symptomatic side of patients with subacute single level posterolateral LIDH. Methods: Fourteen patients with significant sciatic symptoms due to a subacute single-level posterolateral LIDH were reassessed clinically and radiologically at 1.5 years follow-up with a 1.5T MRI scanner. Displacement of the conus medullaris during the unilateral and bilateral SLR was quantified reliably with a randomized procedure and compared between SLRs and to data from baseline. Multivariate regression models and backward variable selection method were employed to identify variables more strongly associated with a decrease in low back pain (LBP) and radicular symptoms. Results: Compared with previously presented baseline values, the data showed a significant increase in neural sliding in all the quantified maneuvers (P ≤ 0.01), and particularly of 2.52 mm (P ≤ 0.001) with the symptomatic SLR.Increase in neural sliding correlated significantly with decrease of both radicular symptoms (Pearson = -0.719, P ≤ 0.001) and LBP (Pearson = -0.693, P ≤ 0.001). Multivariate regression models and backward variable selection method confirmed the improvement of neural sliding effects (P ≤ 0.004) as the main variable being associated with improvement of self- reported clinical symptoms. Conclusion: To our knowledge, these are the first noninvasive data to objectively support the association between increase in magnitude of neural adaptive movement and resolution of both radicular and LBP symptoms in in vivo and structurally intact human subjects. Level of evidence: 2.

STUDY DESIGN This study is a systematic literature review and meta-analysis. OBJECTIVE To evaluate the efficacy of tubular microdiscectomy (TMD) compared with conventional microdiscectomy (CMD) for lumbar disc herniation (LDH). SUMMARY OF BACKGROUND DATA TMD has developed rapidly due to reduced tissue trauma by minimization of the required access to spine and disc herniation; however, CMD remains the standard of care for this patient group. To date, it remains debatable whether TMD is superior to CMD for LDH. METHODS We performed a comprehensive database search of PubMed, EMBASE, and Cochrane Central Register of Controlled Trails for prospective randomized controlled trials (RCTs), through using Medical Subject Headings (MeSH) terms "microdiscectomy," "tubular microdiscectomy," "minimally invasive surgery," and "spinal disease." The retrieved results were last updated on March 15, 2018. Two independent investigators selected qualified studies, extracted indispensable data, assessed risk of bias of original papers. The Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach was used to grade quality of evidence. If I >50, the heterogeneity is considerable. RESULTS Four RCT studies (total n = 605), involving 610 individuals with a follow-up period of no less than 12 months, were selected for further review. We assessed these studies as low overall risk of bias. There was low-quality evidence that TMD was superior to CMD considering postoperative Oswestry Disability Index scores (SMD, -3.43, 95% CI, -4.64 to -2.21, P

STUDY DESIGN: This cohort study was an analysis of prospectively collected data in the DaneSpine Database.OBJECTIVE: The objective was to determine whether preoperative magnetic resonance imaging (MRI) findings were associated with the frequency of surgical revision due to recurrent lumbar disc herniation (LDH) within 3 years after first-time, single-level, simple lumbar discectomy.SUMMARY OF BACKGROUND DATA: Because of a risk of poorer outcome in patients receiving revision surgery compared with first-time discectomy, there is a need to identify patients with LDH in risk of surgical revision prior to the primary discectomy. The association between preoperative MRI findings and revision surgery in patients with LDH has not been thoroughly studied.METHODS: Following an interobserver reliability study preoperative MRIs were evaluated. Potential predictive variables for surgical revision were evaluated using univariate and multivariate logistic regression analysis. Also, a sum-score of the number of MRI findings at the involved level was assessed.RESULTS: In a study population of 451 operated patients, those who had surgical revision were significantly younger and were significantly less likely to have vertebral endplate signal changes Type 2 (OR 0.36 (95% CI 0.15-0.88)) or more than five MRI findings (OR 0.45 (95% CI 0.21-0.95)) at the involved level than the patients not undergoing surgical revision. Surgical revision was not significantly associated with any other MRI findings.CONCLUSIONS: In general, preoperative MRI findings have a limited explanatory value in predicting surgical revision within 3 years after first-time, single-level, simple lumbar discectomy. Both the single variable VESC Type 2 and a sum-score > 5 MRI findings at the operated level were found to be negatively associated with patients undergoing surgical revision.LEVEL OF EVIDENCE: 3.

Retrospective review of prospective data.Determine whether patient reported outcome (PRO) data collected prior to lumbar discectomy predicts achievement of a minimal important difference (MID) after surgery. Compare ability of PRO and clinical information to predict achievement of MID in short term follow-up after discectomy.We investigated the ability of patient reported outcomes measurement information system (PROMIS) and clinical factors at the preoperative time point to determine patients achieving MID after surgery.PROMIS physical function (PF), pain interference (PI), and depression (D) scores were assessed at evaluation and follow-up for consecutive visits between February, 2015 and September, 2017. Patients with preoperative scores within 30 days prior to surgery and with scores 40 days or more after surgery who completed all PROMIS domains were included yielding 78 patients. MIDs were calculated using a distribution-based method. A multivariate logistic regression model was created, and the ability to predict achieving MID for each of the PROMIS domains was assessed. Cut-off values and prognostic probabilities were determined for this model and models combining preoperative PROMIS with clinical data.Preoperative PROMIS scores modestly predict reaching MID after discectomy (areas under the curve [AUC] of 0.62, 0.68, and 0.76 for PF, PI, and D, respectively). Preoperative cut-off scores show patients who have PF and PI scores more than 2 standard deviations, and D more than 1.5 standard deviations worse-off than population mean are likely to achieve MID. The combination of PROMIS with clinical data was the most powerful predictor of reaching MID with AUCs of 0.87, 0.84, and 0.83 for PF, PI, and D.PROMIS scores before discectomy modestly predict improvement after surgery. Preoperative PROMIS combined with clinical factors was more predictive of achieving MID than either clinical factors or PROMIS alone.3.

STUDY DESIGN In-vitro study of the tissue mechanics of annulus fibrosus. OBJECTIVE To determine the effect of axial torsion on the mechanical properties of the inter- and intralamellar matrices. SUMMARY OF BACKGROUND DATA Axial torsion, when combined with repetitive flexion, has been associated with an increased risk of intervertebral disc herniation. However, the mechanisms behind this relationship are poorly understood. METHODS Bovine intervertebral discs (IVDs) from the caudal region were exposed to a combination of either 0° or 12° of static axial torsion and 0 N or 1000 N of compression for 2 hours in an attempt to created micro-damage to the IVD. Following the loading protocol, one multilayered sample and two single layer samples were dissected from the annulus fibrosus to undergo tensile testing of the inter- and intralamellar matrices. Histological staining was also performed. RESULTS The strength of the interlamellar matrix was not affected by axial torsion or compression, suggesting that torsion did not damage the interlamellar matrix. However, intralamellar matrix strength of samples exposed to axial torsion, regardless of compressive loading magnitude, was 48% lower than those from samples that were not exposed to torsion (P

STUDY DESIGN: Qualitative research using semistructured interviews.OBJECTIVE: To explore, from a patient perspective, factors influencing a patient's decision-making process and the decision to have surgery for lumbar disc herniation.SUMMARY OF BACKGROUND DATA: Since strong evidence favoring surgical over nonsurgical treatment is lacking and firm guidelines regarding the optimal timing of surgery are not available, it is essential to involve patients in the decision-making process. Thus the elements that might affect the decision-making process and the decision to have surgery must be identified.METHODS: Using a hermeneutic-phenomenological approach, 14 patients who were referred for primary surgery for lumbar disc herniation were interviewed. Interviews were transcribed and analyzed using a meaning-condensation method to identify themes influencing a patient's decision-making process and the decision to have surgery for lumbar disc herniation.RESULTS: Four main themes that could directly or indirectly influence the patients' decision-making process were identified: A) Patient information: patients' conceptions about treatment were not always based on sufficient information; B) Accelerated workflows: some patients needed time to process the information given, which may be limited due to accelerated workflows; C) Power imbalance: patients can be reluctant to challenge the system, as they do not want to offend, which can be seen as a power imbalance between clinicians and patients; and D) Personal past experience: experience, about treatment options from, i.e., close relatives, can impact patients thoughts about possible treatments.CONCLUSION: Several factors can influence patients' decision-making process and the decision itself: the amount and quality of information received as compared with their preconceived notions, the amount of time given to consider their decision, reluctance to challenge the system and offend the healthcare provider, and past personal experience. Understanding these complex factors will help clinicians to better support patients choosing between surgical and nonsurgical treatment for lumbar herniated disc.LEVEL OF EVIDENCE: 5.

STUDY DESIGN Cost-utility analysis of an annular closure device (ACD) based on data from a prospective, multicenter randomized controlled trial (RCT) OBJECTIVE.: The aim of this study was to determine the cost-effectiveness of a novel ACD in a patient population at high risk for recurrent herniation following discectomy. SUMMARY OF BACKGROUND DATA Lumbar disc herniation patients with annular defect widths ≥6 mm are at high risk for recurrent herniation following limited discectomy. Recurrent herniation is associated with worse clinical outcomes and greater healthcare costs. A novel ACD may reduce the incidence of recurrent herniation and the associated burdens. METHODS A decision analytical modeling approach with a Markov method was used to evaluate the cost-effectiveness of the ACD versus conventional discectomy. Health states were created by projecting visual analogue scale (VAS) onto Oswestry Disability Index (ODI). Direct costs were calculated based on Humana and Medicare 2014 claims to represent private and public payer data, respectively. Indirect costs were calculated for lost work days using 2016 US average annual wages. The incremental cost-effectiveness ratio (ICER) in dollars per quality-adjusted life year (QALY) was compared to willingness-to-pay thresholds. Sensitivity analyses were also conducted. RESULTS Patients with the ACD had less symptomatic reherniations, reoperations, and complications and gained 0.0328 QALYs within the first 2 years. Total direct medical costs for the ACD group were similar to control. When productivity loss was considered, using the ACD became $2076 cheaper, per patient, than conventional discectomy. Based on direct costs alone, the ICER comparing ACD to control equaled $6030 per QALY. When indirect costs are included, the ICER became negative, which indicates that superior quality of life was attained at less cost. CONCLUSION For lumbar disc herniations patients with annular defects ≥6 mm, the ACD was, at 2 years, a highly cost-effective surgical modality compared to conventional lumbar discectomy. LEVEL OF EVIDENCE 1.

Study design A retrospective case-control study. Objective Investigating the correlation between the facet tropism (FT) and subaxial cervical disc herniation (CDH). Summary of background data Although debatable, it was widely reported that FT was associated with lumbar disc herniation. However, the exact correlation between FT and subaxial CDH is still unclear. Methods Two-hundred patients with any disc herniation at C3/4, C4/5, C5/6, or C6/7 and 50 normal participants without CDH (normal control group) were included in this study. For patients, the cervical levels with CDH and the levels without herniation were classified into the "herniation group" and "patient control group," respectively. Bilateral facet joint angles at C3/4, C4/5, C5/6, and C6/7 on sagittal, axial, and coronal planes were measured on computed tomography (CT). The disc degeneration at each level was assessed on magnetic resonance imaging (MRI). Results Both the mean difference between left and right facet angles and tropism incidence in herniation group were significantly greater than those in two control groups whenever at C3/4, C4/5, C5/6, or C6/7 level and whenever on sagittal, axial, or coronal plane. The mean differences of angles and tropism incidences in most patient control groups were not significantly greater than those of corresponding normal control groups. The incidence of greater facet angle at the left or right side was not significantly different among the left, central, and right herniation groups. The mean disc degeneration grades in both herniation and patient control groups were significantly higher than those in normal control groups while no difference between herniation and patient control groups. Conclusion The FT on the sagittal, axial, and coronal planes are all associated with CDH in the subaxial cervical spine. The greater facet angle at the left or right side does not affect the side of herniation. The severity of cervical disc degeneration is not associated with FT.Level of Evidence: 3.

STUDY DESIGN A prospective study. OBJECTIVE The aim of this study was to investigate the relationship between diffusion tensor imaging (DTI) derived parameters of compressed nerve roots at subregions and the corresponding clinical symptoms to evaluate the patients with intraspinal lumbar disc herniation (LDH)-related lumbosacral radiculopathy pre- and postoperatively. SUMMARY OF BACKGROUND DATA It is crucial to explore whether magnetic resonanve imaging (MRI) can quantitatively evaluate intraspinal LDH-related lumbosacral radiculopathy before and after surgery. METHODS In all, 66 patients underwent MRI scans and Clinical assessment before and after percutaneous transforaminal endoscopic discectomy (PTED). Pre- and postoperative findings of the related lumbar disk and nerve tractography were compared with two-way contingency table analysis. The embedded paired t test toolbox was applied to respectively compare the fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of nerves at the symptomatic and asymptomatic sides in three subregions pre- and postoperatively. The correlation of clinical Japanese Orthopedic Association (JOA) scores and FA/ADC values of nerves at three sub-regions was analyzed by stepwise multiple linear regression analysis. RESULTS The postoperative FA values were significantly higher than the corresponding preoperative values (P

Observational study.The aim of this study was to evaluate whether inflammatory and/or muscle regeneration markers in paraspinal tissues (multifidus muscle/fat) during microdiscectomy surgery in patients with lumbar disc herniation (LDH) with radiculopathy, differ between individuals with good or poor outcome.Structural back muscle changes, including fat infiltration, muscle atrophy, and fiber changes, are ubiquitous with LBP and are thought to be regulated by inflammatory and regeneration processes. Muscle changes might be relevant for recovery after microdiscectomy, but a link between expression of inflammatory and muscle regeneration genes in paraspinal tissues and clinical outcome has not been tested.Paraspinal tissues from deep multifidus muscles and fat (intramuscular, sub-cutaneous, epidural) were harvested from twenty-one patients with LDH undergoing microdiscectomy surgery. Quantitative polymerase chain reaction (qPCR) measured expression of 10 genes. Outcome was defined as good (visual analogue scale (VAS) low back pain (LBP)+) or poor (VAS LBP-) by an improvement of33% or ≤33% on the pain VAS, respectively. Good functional improvement was defined as 25% improvement on the physical functioning scale (PFS).Brain-derived neurotrophic factor expression in deep multifidus was 91% lower (P = 0.014) in the VAS LBP- than VAS LBP+ group. Expression of interleukin-1β in subcutaneous fat was 48% higher (P = 0.026) in the VAS LBP- than VAS LBP+ group. No markers differed based on PFS.Results show a relationship between impaired muscle regeneration profile in multifidus muscle and poor outcome following microdiscectomy for LDH. Inflammatory dysregulation in subcutaneous fat overlying the back region might predict poor surgical outcome.Level of Evidence: 4.

Study design Observational multicenter study. Objective The aim of this study was to evaluate changes in pain during sexual activity after surgery for lumbar disc herniation (LDH). Summary of background data There are limited data available on sexual function in patients undergoing surgery for LDH. Methods Data were retrieved from the Norwegian Registry for Spine Surgery. The primary outcome was change in pain during sexual activity at one year, assessed by item number eight of the Oswestry disability index (ODI) questionnaire. Secondary outcome measures included ODI, EuroQol-5D (EQ-5D), and numeric rating scale (NRS) scores for back and leg pain. Results Among the 18,529 patients included, 12,103 (64.8%) completed 1-year follow-up. At baseline, 16,729 patients (90.3%) provided information about pain during sexual activity, whereas 11,130 (92.0%) among those with complete follow-up completed this item. Preoperatively 2586 of 16,729 patients (15.5%) reported that pain did not affect sexual activity and at 1 year, 7251 of 11,130 patients (65.1%) reported a normal sex-life without pain. Preoperatively, 2483 (14.8%) patients reported that pain prevented any sex-life, compared to 190 patients (1.7%) at 1 year. At baseline, 14,143 of 16,729 patients (84.5%) reported that sexual activity caused pain, and among these 7232 of 10,509 responders (68.8%) reported an improvement at 1 year. A multivariable regression analysis showed that having a life partner, college education, working until time of surgery, undergoing emergency surgery, and increasing ODI score were predictors of improvement in pain during sexual activity. Increasing age, tobacco smoking, increasing body mass index, comorbidity, back pain >12 months, previous spine surgery, surgery in two or more lumbar levels, and complications occurring within 3 months were negative predictors. Conclusion This study clearly demonstrates that a large proportion of patients undergoing surgery for LDH experienced an improvement in pain during sexual activity at 1 year. Level of evidence 2.

STUDY DESIGN A retrospective study. OBJECTIVE The aim of this study was to describe a novel posterior approach, circumspinal decompression technique "IV+V+VI" for ossification of the posterior longitudinal ligament (OPLL) or hard disc herniation (HDH) in thoracic spine and assess its safety and efficacy. SUMMARY OF BACKGROUND DATA Thoracic myelopathy caused by OPLL or HDH is a rare but intractable disorder that can only be effectively treated with surgery. Nevertheless, few studies have reported on a detailed resection of OPLL or HDH using a single posterior approach and no consistent procedures have been established. METHODS Fifteen consecutive patients with single-level OPLL or HDH who were treated with this novel technique at our center between January 2016 and June 2017 were recruited. The perioperative complications, operation time, blood loss, pre- and postoperative neurological statuses were recorded and analyzed. Neurological status was evaluated with a modified Japanese Orthopaedic Association (JOA) scale and the neurological recovery rate was calculated using the Hirabayashi's Method. RESULTS All the included patients underwent one-stage posterior circumferential decompression. The average age at surgery was 43.3 ± 12.8 years. Eight cases were diagnosed with HDH, four with OPLL, and three with OPLL+OLF (ossification of the ligamentum flavum). The mean operation time was 109.9 ± 25.3 minutes with an average blood loss of 433.3 ± 221.8 mL. The mean follow-up period was 33.1 ± 7.5 months. Five patients experienced a dural tear, whereas another case experienced a transient numbness in the right lower limb. All these patients were treated conservatively and their neurological function recovered well at the final follow-up. The average JOA score increased from 5.8 ± 1.9 before surgery to 10.2 ± 1.0 postoperatively, and the average recovery rate was 87.2%. CONCLUSION The "IV+V+VI" technique is a safe and effective method for thoracic OPLL and HDH resection. It can be used as a standard surgical procedure for thoracic spinal circumferential decompression. LEVEL OF EVIDENCE 4.

STUDY DESIGN A retrospective case-control study. OBJECTIVE To investigate the correlation between lumbar disc herniation (LDH) and lumbar facet tropism (FT) on cephalad and caudad facet portions, respectively; to investigate the asymmetry between ipsilateral cephalad and caudad facet portions and its correlation with LDH. SUMMARY OF BACKGROUND DATA There are still heavy debates on the exact correlation between lumbar FT and LDH. However, no study ever focused on the FT on different facet portions and asymmetry between ipsilateral cephalad and caudad portions in patients with LDH. METHODS One hundred patients with L4/5 LDH, 100 patients with L5/S1 LDH, and 100 participants without LDH (control group) were age and sex matched and included in this study. Participants in each group were further divided into two subgroups based on age (≥ or < 50 yr old). Bilateral facet joint angles on both cephalad and caudad portions were measured. FT and asymmetry between ipsilateral cephalad and caudad portions in each LDH group were compared with those in corresponding control group. RESULTS Comparing with control participants, the mean difference of bilateral facet angles in older patients with L4/5 LDH was significantly greater either on cephalad portion and caudad portion, whereas significantly higher frequency of FT was only exhibited on cephalad portion. In older patients with L4/5 LDH, the mean difference of facet angle between ipsilateral cephalad and caudad portions was significantly greater than that of control participants, the frequency of ipsilateral cephalad, and caudad facet asymmetry was also significantly higher. CONCLUSIONS Only the FT on cephalad portion but not caudad portion of facet joint is associated with L4/5 LDH of older patients. The measurement on different portions of facet joint may result in discrepancy on FT identification. Asymmetry between ipsilateral cephalad and caudad facet portions is also associated with L4/5 LDH in older patients. LEVEL OF EVIDENCE 3.

Study design A retrospective cohort study. Objective To investigate the 30-day recurrence rate after emergency lumbar discectomy. Secondary aims were to investigate the factors affecting the 30-day recurrence and readmission rates and clinical outcome. Summary of background data Excluding cauda equine syndrome (CES) due to massive intervertebral disc herniation, emergency surgery for lumbar disc herniation (LDH) is rarely required. The operation may, however, be performed for other reasons such as persistent or progressive motor paresis associated with radiculopathy or uncontrolled pain. Literature on these topics is scarce. Methods All patients admitted for inpatient care after a visit to the emergency department (ED) due to acute low back pain and who had subsequently undergone an emergency lumbar discectomy during the 4-year study period were included in the study. Patients attending the ED who subsequently had a delayed discectomy formed the control group. Recurrence and readmission rates were analyzed and clinical outcome at 30 days post-surgery was assessed with the Oswestry Disability Index (ODI) and the visual analog pain scale (VAS). Results One hundred thirty patients were admitted to the hospital after visiting the ED and underwent an emergency discectomy after a median of 1.0 days from admittance. Six patients in the study group [4.6% (95% CI: 2.1-9.7)] had recurrent LDH and nine patients in total [6.9% (95% CI: 3.9-12.6)] were readmitted within 30 days. None of the baseline variables clearly predicted recurrence. Mean ODI difference between the study group and controls was 8.1 (95% CI: -6.7-23.2). BMI and surgery by a non-spine surgeon were associated with higher ODI values. Conclusion An emergency discectomy is associated with a higher rate than expected of both recurrent LDHs and 30-day readmissions. Surgeon experience and patient-related factors had minor effects on the 30-day clinical outcome. Level of evidence 4.

STUDY DESIGN: Registry-based repeated-measures psychometric validation of the Danish Oswestry Disability Index (ODI).OBJECTIVE: The goal was to use classical and modern psychometric validation methods to assess the measurement properties and the minimally clinical important difference (MCID) of the ODI in a Danish cohort of patients with chronic low back pain being treated with spinal surgery.SUMMARY OF BACKGROUND DATA: Scores for the ODI, EQ-5D, SF-36, leg pain, back pain, and a general rating of pain item from 800 patients with chronic low back pain were extracted from the National Danish Spine Registry (DaneSpine) at baseline and 1-year postspine surgery.METHODS: Confirmatory factor analysis and item response theory (IRT) models were used to assess the psychometric properties of the ODI. MCID was also calculated based on generic legacy PROMs (EQ-5D and SF-36) and follow-up pain scores.RESULTS: While ODI did not fit a Rasch model, adequate fit to a confirmatory factor analysis and a two-parameter item response theory model was found when accounting for differential item functioning across diagnostic subgroups (degenerative spondylolisthesis, spondylosis, spinal stenosis, and herniated intervertebral disc). In addition, each group exhibited substantially different MCID values.CONCLUSION: The Danish version of the ODI is valid and responsive, but only within each of the four major diagnosis subgroups: degenerative spondylolisthesis, spondylosis, spinal stenosis, and herniated intervertebral disc.LEVEL OF EVIDENCE: 4.

Retrospective clinical series.To investigate the clinical features and the risk factors for recurrent lumbar disc herniation (rLDH) in China.rLDH is a common cause of poor outcomes after lumbar microdiscectomy surgery. Risk factors for rLDH are increasingly being investigated. However, results in these previous studies were not always consistent.Between June 2005 and July 2012, 321 consecutive patients with single-level LDH, who underwent surgery, were enrolled in this study. We divided the patients into the recurrent group (R group) and the nonrecurrent group (N group) and compared their clinical parameters and preoperative radiologic parameters. The relationships between the variables and rLDH were evaluated by univariate analysis and multiple logistic regression analysis.There was significant difference between groups in sex (P = 0.003), age (P = 0.003), current smoking (P = 0.004), body mass index (BMI) (P = 0.04), occupational lifting (P 0.001), trauma history (P = 0.04), procedures (P = 0.04), herniation type (P = 0.006), disc height index (DUI) (P = 0.04), facet orientation (FO) (P = 0.04), facet tropism (FT) (P = 0.04), and sagittal range of motion (from) (P = 0.04). By putting these differences in logistic regression analysis, it showed that being male, young age, current smoking, higher BMI, herniation type (transligamentous extrusion), surgical procedures (bilateral laminectomy or total laminectomy), heavy works, undergoing a traumatic event, a large from, a high DUI, a large FT, and a small FO significantly related with rLDH.Based on our data, sex, age, current smoking, BMI, occupational lifting, trauma, surgical procedures, herniation type, DUI, FO, FT, and from showed a significant correlation with the incidence of rLDH. Patients with these risk factors should be paid more attention for prevention of recurrence after primary surgery.3.

Study design Microstructural investigation of compression-induced herniation of a lumbar disc held in a concordant complex posture. Objective To explore the significance of loading rate in a highly asymmetric concordant posture, comparing the mechanisms of failure to an earlier study using a nonconcordant complex posture. Summary of background data A recent study with a nonconcordant complex posture (turning in the opposite direction to that which the load is applied) demonstrated the vulnerability of the disc to loading that is borne by one set of oblique-counter oblique fiber sets in the alternating lamellae of the annulus, and aggravated by an elevated loading rate. Given the strain rate-dependent properties of the disc it might be expected that the outcome differs if the posture is reversed. Methods Forty-one motion segments from ovine 16 spines were split into two cohorts; adopting the previously employed low rate (40 mm/min) and surprise rate (400 mm/min) of loading. Both groups of damaged discs were then analyzed microstructurally. Results With the lower rate loading the concordant posture significantly reduced the load required to cause disc failure than earlier described for nonconcordant posture (6.9 vs. 8.4 kN), with more direct tears and alternate lamella damage extending to the anterior disc. Contrary to this result, with a surprise rate, the load at failure was significantly increased with the concordant posture (8.08 vs. 6.96 kN), although remaining significantly less than that from a simple flexed posture (9.6 kN). Analysis of the damage modes and postures suggest facet engagement plays a significant role. Conclusion This study confirms that adding shear to the posture lowers the load at failure, and causes alternate lamella rupture. Load at failure in a complex posture is not determined by loading rate alone. Rather, the strain rate-dependent properties of the disc influence which elements of the system are brought into play. Level of evidence N/A.

A randomized, double-blind, placebo-controlled, multicenter phase III clinical trial.To evaluate the efficacy and safety of chemonucleolysis with condoliase in patients with lumbar disc herniation (LDH).Condoliase is a pure mucopolysaccharidase derived from a bacterium, Proteus vulgaris that has high substrate specificity for chondroitin sulfate and hyaluronic acid in the nucleus pulposus of the intervertebral disc.In this study, patients aged 20 to 70 years with unilateral leg pain, positive straight leg raise test, and a contained LDH were recruited in Japan. Patients were treated with a single injection of condoliase (1.25 U) or placebo and were followed for 1 year after administration. The primary endpoint was change in worst leg pain from baseline to week 13. The secondary endpoints included responder rate, and the changes from baseline up to week 52 in the worst leg pain, worst back pain, Oswestry Disability Index, 36-Item Short-Form Health Survey, neurologic examinations, and imaging parameters.A total of 82 and 81 patients received an injection of condoliase and placebo, respectively. The average changes in worst leg pain from baseline to week 13 (primary endpoint) were -49.5 mm in the condoliase group and -34.3 mm in the placebo group, and the difference of -15.2 mm was significant (95% confidence interval, -24.2 to -6.2; P = 0.001). Significant improvements were observed in the condoliase groups, compared with the placebo group, in most secondary endpoints at 1 year after administration. In the condoliase group, back pain, Modic type 1 change, and decrease in disc height were frequently reported, without any clinically relevant consequences.Condoliase significantly improved symptoms in patients with LDH and was well tolerated. Condoliase is a novel and potent chemonucleolytic drug for the treatment of LDH.1.

Study design A study of mechanically induced herniation in punctured ovine discs followed by structural analysis. Objective To investigate whether an annular puncture influences the path that herniation takes by providing direct passage for nucleus through the annulus and therefore whether it increases the risk of acute herniation from overload at the site of damage independent of any longer-term degeneration. Summary of background data Ten years after treatment with discography both degenerative changes and frequency of herniation have been shown to increase compared to untreated discs. Although the effect of an annular puncture over time has been widely investigated the question of whether it increases the risk of acute herniation has not been resolved. Methods The posterolateral annuli of healthy ovine lumbar discs were punctured with either a 25-gauge (n = 8) or a larger 18-gauge (n = 8) needle and then compressed in a flexed posture of 10° until initial indications of failure. The entire volume of the disc was visually assessed for structural damage by obtaining progressive, full transverse cross-sections of its entire height thus exposing all regions of the disc. Results There was no association between the 25-gauge puncture and disc disruption and herniation. In contrast, nuclear material was observed to migrate through the 18-gauge needle puncture. Disruption of the lateral inner annulus was observed in 12 out of the 16 discs tested. Conclusion The risk of acute herniation through the puncture site is dependent on the needle diameter used. Under the conditions employed the lateral inner annulus remains the site most vulnerable to disruption independent of the presence of a posterolateral puncture. Level of evidence N /A.

Study Design. Systematic review and meta-analysis of comparative studies. Objective. To characterize the association of annular defect width after lumbar discectomy with the risk of symptom recurrence and reoperation. Summary of Background Data. Large annular defect width after lumbar discectomy has been reported to increase risk of symptom recurrence. However, this association has not been evaluated in a systematic manner. Methods. A systematic literature search of MEDLINE and EMBASE was performed to identify comparative studies of large versus small annular defects following lumbar discectomy that reported symptom recurrence or reoperation rates. Main outcomes were reported with pooled odds ratios (OR) and 95% confidence intervals (CIs). Sensitivity analyses were performed to assess the robustness of the meta-analysis findings. Results. After screening 696 records, we included data from 7 comparative studies involving 1653 lumbar discectomy patients, of whom 499 (30%) had large annular defects and 1154 (70%) had small annular defects. Methodological quality of studies was good overall. The median follow-up period was 2.9 years. The risk of symptom recurrence (OR = 2.5, 95% CI = 1.3–4.5, P = 0.004) and reoperation (OR = 2.3, 95% CI = 1.5–3.7, P

Study design A retrospective study. Objective The aim of this study was to evaluate the clinical and radiological outcomes of mini-open ALIF (MO-ALIF) with self-anchored stand-alone cages for the treatment of lumbar disc herniation in comparison with transforaminal lumbar interbody fusion (TLIF). Summary of background data Currently, whether ALIF is superior to TLIF for the treatment of lumbar disc herniation remains controversial. Methods This study retrospectively reviewed 82 patients who underwent MO-ALIF with self-anchored standalone cages (n = 42) or TLIF (n = 40) for the treatment of lumbar disc herniation between April 2013 and October 2014. Patient demographics, intraoperative parameters, and perioperative complications were collated. Clinical outcomes were evaluated using the visual analog scale (VAS) scoring, the Oswestry Disability Index (ODI) for pain in the leg and back, and radiological outcomes, including fusion, lumbar lordosis (LL), disc height (DH), and cage subsidence were evaluated at each follow-up for up to 2 years. Results Patients who underwent TLIF had a significantly higher volume of blood loss (295.2 ± 81.4 vs. 57.0 ± 15.2 mL) and longer surgery time (130.7 ± 45.1 vs. 60.4 ± 20.8 min) than those who had MO-ALIF. Compared with baseline, both groups had significant improvements in the VAS and ODI scores and DH and LL postoperatively, though no significant difference was found between the two groups regarding these indexes. All patients reached solid fusion at the final follow-up in both groups. Three patients (3/42) with three levels (3/50) suffered from cage subsidence in the MO-ALIF group; meanwhile, no cage subsidence occurred in the TLIF group. Conclusion MO-ALIF with self-anchored stand-alone cages is a safe and effective treatment of lumbar disc herniation with less surgical trauma and similar clinical and radiological outcomes compared with TLIF. Level of evidence 3.

A multicenter, population based, case-control study.The aim of the present analysis is to clarify potential differences in the "occupational risk profiles" of structural lumbar disc diseases on the one hand, and low back pain (LBP) on the other hand.Physical workplace factors seem to play an important etiological role.We recruited 901 patients with structural lumbar disc diseases (disc herniation or severe disc space narrowing) and 233 control subjects with "low-back-pain." Both groups were compared with 422 "low-back pain free" control subjects. Case history, pain data, neurological deficits, and movement restrictions were documented. LBP was recorded by the Nordic questionnaire on musculoskeletal symptoms. All magnetic resonance imaging, computed tomography, and X-rays were inspected by an independent study radiologist. The calculation of cumulative physical workload was based on a computer-assisted interview and a biomechanical analysis by 3-D-dynamic simulation tool. Occupational exposures were documented for the whole working life.We found a positive dose-response relationship between cumulative lumbar load and LBP among men, but not among women. Physical occupational risks for structural lumbar disc diseases [odds ratio (OR) 3.7; 95% confidence interval (95% CI) 2.3-6.0] are higher than for LBP (OR 1.9; 95% CI 1.0-3.5).Our finding points to potentially different etiological pathways in the heterogeneous disease group of LBP. Results suggest that not all of the structural disc damage arising from physical workload leads to LBP.4.