Radiological analysis of upper lumbar disc herniation and spinopelvic sagittal alignment

Purpose

A retrospective cross-sectional study was designed to explore the role of spinopelvic sagittal alignment in upper lumbar disc herniation (ULD) development.

Methods

A total of 207 consecutive patients who underwent surgery for single-level lumbar disc herniation [24 with ULD and 183 with lower lumbar disc herniation (LLD)] and 40 asymptomatic volunteers were enrolled. Full-length radiographs of the spine were taken to evaluate pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), thoracic kyphosis (TK), lumbar lordosis (LL), and sagittal vertical axis (SVA). The Roussouly classification was utilized to categorize all subjects according to their sagittal alignment. Spinopelvic parameters and Roussouly classification results were compared between groups.

Results

There were significant differences in PI, SS, PT, LL, and SVA between the ULD, LLD, and control groups. PI in the ULD (40.9°) was significantly lower than in the LLD and control groups (48.8° and 47.6°, respectively). LL was significantly lower in the ULD than in the LLD (?32.4° and ?40°, respectively). There were significant differences between the three groups in Roussouly types. The LLD had a significantly higher proportion (62.6 %) of type 2 lordosis (flat back), and the ULD had a higher proportion (33.3 %) of type 1 lordosis than the other groups.

Conclusions

This study demonstrated the importance of PI and lumbar curvature in the pathogenesis of ULD. The higher prevalence of short LL and long TK with low PI in the ULD group implies that an increased mechanical stress at this level may be one of the risk factors of ULD.

     

The role of intense athletic activity on structural lumbar abnormalities in adolescent patients with symptomatic low back pain

Purpose

To determine if adolescent athletics increases the risk of structural abnormalities in the lumbar spine.

Methods

A retrospective review of patients (ages 10–18) between 2004 and 2012 was performed. Pediatric patients with symptomatic low back pain, a lumbar spine MRI, and reported weekly athletic activity were included. Patients were stratified to an “athlete” and “non-athlete” group. Lumbar magnetic resonance and plain radiographic imaging was randomized, blinded, and evaluated by two authors for a Pfirrmann grade, herniated disc, and/or pars fracture.

Results

A total of 114 patients met the inclusion criteria and were stratified into 66 athletes and 48 non-athletes. Athletes were more likely to have abnormal findings compared to non-athletes (67 vs. 40 %, respectively, p = 0.01). Specifically, the prevalence of a spondylolysis with or without a slip was higher in athletes vs. non-athletes (32 vs. 2 %, respectively, p = 0.0003); however, there was no difference in the average Pfirrmann grade (1.19 vs. 1.14, p = 0.41), percentage of patients with at least one degenerative disc (39 vs. 31 %, p = 0.41), or disc herniation (27 vs. 33 %, p = 0.43). Body mass index, smoking history, and pelvic incidence (51.5° vs. 48.7°, respectively, p = 0.41) were similar between the groups.

Conclusion

Adolescents with low back pain have a higher-than-expected prevalence of structural pathology regardless of athletic activity. Independent of pelvic incidence, adolescent athletes with low back pain had a higher prevalence of spondylolysis compared to adolescent non-athletes with back pain, but there was no difference in associated disc degenerative changes or herniation.

     

The distribution of infection with <Emphasis Type="Italic">Propionibacterium acnes</Emphasis> is equal in patients with cervical and lumbar disc herniation

Background

Cervical and back pains are important clinical problems affecting human populations globally. It is suggested that Propionibacterium acnes (P. acnes) is associated with disc herniation. The aim of this study is to evaluate the distribution of P. acnes infection in the cervical and lumbar disc material obtained from patients with disc herniation.

Methods and material

A total of 145 patients with mean age of 45.21 ± 11.24 years who underwent micro-discectomy in cervical and lumbar regions were enrolled into the study. The samples were excited during the operation and then cultured in the anaerobic incubations. The cultured P. acnes were detected by 16S rRNA-based polymerase chain reaction.

Results

In this study, 145 patients including 25 cases with cervical and 120 cases with lumbar disc herniation were enrolled to the study. There was no significant difference in the age of male and female patients (p = 0.123). P. acnes infection was detected in nine patients (36%) with cervical disc herniation and 46 patients (38.3%) with lumbar disc herniation and no significant differences were reported in P. acnes presence according to the disc regions (p = 0.508.). Moreover, there was a significant difference in the presence of P. acnes infection according to the level of lumbar disc herniation (p = 0.028).

Conclusion

According to the results, the presence of P. acnes is equal in patients with cervical and lumbar disc herniation. There was a significant difference in the distribution of P. acnes infection according to level of lumbar disc herniation.

Level of Evidence

II

     

Are lumbar multifidus fatigue and transversus abdominis activation similar in patients with lumbar disc herniation and healthy controls? A case control study

Purpose

The aims of this study were to assess lumbar multifidus fatigue (LM) and transversus abdominis activation (TrA) in individuals with lumbar disc herniation associated with low back pain.

Methods

Sixty individuals were divided into the lumbar herniation (LHG, n = 30) and control groups (CG, n = 30). Fatigue of the LM was assessed using surface electromyography during the Sorensen effort test, and activation of the TrA with a pressure biofeedback unit. Pain intensity was determined using a visual analog scale and the McGill pain questionnaire. The Oswestry disability questionnaire and the Borg scale for self-evaluating exertion were used to assess functional disability.

Results

Fatigue was significantly more intense and the TrA activation was insufficient (p < 0.01) in individuals with disc herniation relative to the control group. The LHG had mild functional disability and moderate pain. There were differences in the initial exertion self-evaluation between groups, which were not observed in the final exertion evaluation.

Conclusion

Individuals with lumbar disc herniation associated with low back pain have increased fatigue of the LM and decreased activation of the TrA, when compared to the control group.

     

The Pfirrmann classification of lumbar intervertebral disc degeneration: an independent inter- and intra-observer agreement assessment

Purpose

Grading inter-vertebral disc degeneration (IDD) is important in the evaluation of many degenerative conditions, including patients with low back pain. Magnetic resonance imaging (MRI) is considered the best imaging instrument to evaluate IDD. The Pfirrmann classification is commonly used to grade IDD; the authors describing this classification showed an adequate agreement using it; however, there has been a paucity of independent agreement studies using this grading system. The aim of this study was to perform an independent inter- and intra-observer agreement study using the Pfirrmann classification.

Methods

T2-weighted sagittal images of 79 patients consecutively studied with lumbar spine MRI were classified using the Pfirrmann grading system by six evaluators (three spine surgeons and three radiologists). After a 6-week interval, the 79 cases were presented to the same evaluators in a random sequence for repeat evaluation. The intra-class correlation coefficient (ICC) and the weighted kappa (wκ) were used to determine the inter- and intra-observer agreement.

Results

The inter-observer agreement was excellent, with an ICC = 0.94 (0.93–0.95) and wκ = 0.83 (0.74–0.91). There were no differences between spine surgeons and radiologists. Likewise, there were no differences in agreement evaluating the different lumbar discs. Most differences among observers were only of one grade. Intra-observer agreement was also excellent with ICC = 0.86 (0.83–0.89) and wκ = 0.89 (0.85–0.93).

Conclusions

In this independent study, the Pfirrmann classification demonstrated an adequate agreement among different observers and by the same observer on separate occasions. Furthermore, it allows communication between radiologists and spine surgeons.

     

Risk factors for the need of surgical treatment of a first recurrent lumbar disc herniation

Purpose

A recurrent lumbar disc herniation (RLDH) is the most prevalent cause for new radicular pain after surgery for disc herniation-induced sciatica. Reported risk factors include age, gender and smoking, while its surgical treatment is associated to a higher rate of complications and costs. The purpose of this study is to identify factors that increase the risk of requiring surgical treatment for a first RLDH in workers’ compensation patients.

Methods

Nested case–control: 109 patients operated for an RLDH (cases) between June 1st 1994 and May 31st 2011 (minimum follow-up 1 year) and 109 randomly selected patients operated for a first disc herniation with no recurrence during the study period (controls). Age, gender, smoking status, type of work and MRI characteristics of the index herniation were statistically evaluated as potential risk factors.

Results

Patient’s age of less than 35 years (p = 0.001) and a subligamentous herniation (p < 0.05) at the time of the index surgery were identified as risk factors for requiring surgical treatment of a first RLDH. No statistical differences were observed between both groups regarding the other evaluated variables.

Conclusion

A subligamentous disc herniation and patient’s age inferior to 35 years at the time of the first surgery are risk factors for requiring surgical treatment of a first RLDH among workers’ compensation patients.

     

Multidimensional long-term outcome analysis after single-level lumbar microdiscectomy: a retrospective single-centre study

Objective

To present multidimensional long-term results after mono-segmental microdiscectomy for lumbar disc herniation (LDH) in a large adult cohort treated at a tertiary care centre.

Methods

Retrospective study design with Oswestry Disability Index (ODI) questionnaire employed at follow-up. All patients undergoing surgical treatment for single-level LDH between 2003 and 2009 were identified. Electronic patient records and imaging data were analysed.

Results

A total of 939 patients underwent single-level lumbar MD at our institution. Three hundred and seven complete ODI forms (32.7%) were returned at a median follow-up of 48 months. Mean ODI score was 24.04, and mean age was 58 years. Females reported slightly higher ODI scores (25.52 vs. 22.68). Age and ODI score showed statistically significant correlation. Early surgery yielded lower ODI scores with patients faring significantly worse if symptoms persisted for a year or longer (one-way ANOVA, p < 0.001). ODI scores increased sharply even among those operated later than 1 week after symptom onset. Sequestered herniations were associated with significantly lower ODI scores than contained discs on MRI (21.96 vs. 39.89). Surgical complications occurred in 17 cases (5.6%), 82 patients (26.7%) required additional surgery, 58 (18.9%) of those for recurrent disc herniations.

Conclusion

Our findings suggest better outcomes with early surgical treatments. Time limits for conservative treatments should be set to avoid the chronification of pain and the worse overall outcomes that go along with belated surgery. Particularly in those with acute onset of pain, sequestered herniations and only mild degrees of immobilization good outcomes are common and surgical treatment appears best if indicated early.

     

Axial loading during MRI influences T2-mapping values of lumbar discs: a feasibility study on patients with low back pain

Purpose

To investigate whether axial loading of the spine during MRI (alMRI) instantaneously induces changes in biochemical disc features as reflected by altered quantitative T2 values in patients with chronic low back pain (LBP).

Methods

T2 mapping was performed on 11 LBP patients (54 lumbar discs) during the conventional unloaded MRI and subsequent alMRI. Each disc was divided into five volumetric regions of interests (ROIs), anterior annulus fibrosus (AF) (ROI 1), the interface anterior AF-nucleus pulposus (NP) (ROI 2), NP (ROI 3), the interface NP-posterior AF (ROI 4), and the posterior AF (ROI 5). The mean T2 values for each ROI were compared between MRI and alMRI and correlated with degeneration grade (Pfirrmann), disc angle, and disc level.

Results

With alMRI, T2 values increased significantly in the whole disc as well as in various parts of the disc with an increase in ROI 1–3 and a decrease in ROI 5. The changes in T2 values correlated to degeneration grade, changes in disc angle, and lumbar level.

Conclusion

alMRI instantaneously induces T2-value changes in lumbar discs and is, thus, a feasible method to reveal dynamic, biochemical disc features in patients with chronic LBP.

     

Postdural disc herniation at L5/S1 level mimicking an extradural spinal tumor

Introduction

Postdural disc herniation has been documented rarely and the pathogenesis is still unknown. The average age of postdural disc herniations is between 50 and 60 years, and the sites most frequently affected by postdural lumbar disc herniations are L3–L4 and L4–L5, only less than 10 % in L5–S1. Although magnetic resonance imaging (MRI) is a useful tool in the diagnosis of this disease, the postdural disc herniation is usually misdiagnosed as extradural spine tumor preoperatively. The definitive diagnosis is made during operation or according to the postoperative pathology.

Methods

In this article, we described here a 48-year-old male patient who presented with intermittent pain in the low back and frequent urination for 4 years as well as hypesthesia and pain of the left lower extremity for 1 month.

Results

A standard total laminectomy was performed and the histopathological diagnosis was consistent with a degenerated intervertebral disc. The patient presented significant relief of the pain and of the neurological symptoms, but no improvement of frequent urination, in the postoperative period.

Conclusions

The diagnosis of postdural disc herniations is very difficult and mainly based on intraoperative and histopathological results. Early surgical intervention is important to relieve symptoms and prevent severe neurological deficits.

     

Microendoscopic discectomy versus open discectomy for lumbar disc herniation: a meta-analysis

Purpose

To compare the outcomes of microendoscopic discectomy and open discectomy for patients with lumbar disc herniation.

Methods

An extensive search of studies was performed in PubMed, Medline, Embase, Cochrane library and Google Scholar. The following outcome measures were extracted: visual analogue scale (VAS), Oswestry disability index (ODI), complication, operation time, blood loss and length of hospital stay. Data analysis was conducted with RevMan 5.0.

Results

Five randomized controlled trials involving 501 patients were included in this meta-analysis. The pooled analysis showed that there was no significant difference in the VAS, ODI or complication between the two groups. However, compared with the open discectomy, the microendoscopic discectomy was associated with less blood loss [WMD = ?151.01 (?288.22, ?13.80), P = 0.03], shorter length of hospital stay [WMD = ?69.33 (?110.39, ?28.28), P = 0.0009], and longer operation time [WMD = 18.80 (7.83, 29.76), P = 0.0008].

Conclusions

Microendoscopic discectomy, which requires a demanding learning curve, may be a safe and effective alternative to conventional open discectomy for patients with lumbar disc herniation.

     

Does surgery for Scheuermann kyphosis influence sagittal spinopelvic parameters?

Purpose

To analyze changes in sagittal spinopelvic parameters (SSPs) after surgical treatment of Scheuermann’s Kyphosis (SK).

Methods

We analyzed 20 patients affected by SK and subjected to posterior correction of the kyphosis by facetectomy, Ponte osteotomy, fusion and multilevel instrumentation with pedicle screw system. Four spinal and three pelvic parameters were measured: sagittal vertical axis (SVA), thoracic kyphosis (TK), thoracolumbar kyphosis, lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS) and pelvic tilt (PT). Analysis of changes in postprocedural SSPs compared to preoperative values was performed.

Results

TK passed from 78.6° preoperatively to 45.8° (p = 0.003). LL passed from 74.5° preoperatively to 53.5° (p = 0.01). No significant changes occurred in SVA, SS, PT and PI compared to preoperative values.

Conclusion

We confirm the positive effect of surgery by Ponte osteotomy and posterior spinal fusion on TK and LL in patients with SK. In our experience, pelvic parameters did not change after surgery.

     

Reliability of cervical radiculopathy,its congruence between patient history and medical imaging evidence of disc herniation and its role in surgical decision

Background

The incidence of cervical disc herniation is estimated about 5.5/100,000, and they lead to surgical intervention in 26 %. Cervical disc herniation causes radiculopathy, which defines by radicular pain and sensory deficit and maybe weakness following the path of the affected nerves. Classically, cervical radiculopathy is expected to follow its specific dermatome—C4, C5, C6, C7 and C8. We investigate patients who present with discrepancy between classical radiculopathy and imaging findings in the daily practice of our profession.

Methods

We reviewed the medical records of 102 patients with cervical radiculopathy, caused by cervical disc herniation. All patients had surgery.

Results

We found an apparent discrepancy between clinical and radiological findings, patients complained of radiculopathy on one side, and magnetic resonance imaging (MRI) scan or CT scan finding on the other side in ten patients (10.2 %). We did not found any other abnormalities in preoperative and post-operative period. All patients underwent cervical diskectomy via anterior approach. Six weeks after surgery eight patients (80 %) recovered completely, and 3 months after all ten patients (100 %) had been relieved totally.

Comparison with existing method

The aim of this paper is review of this medical concept and management of radiculopathy in patients with this discrepancy. As far as we know, the subject has not yet been touched in this light in medical literature.

Conclusion

The discrepancy between clinical radiculopathy and disc herniation level on MRI or on CT scan is not rare. Management of this discrepancy requires further investigation to avoid missing diagnosis and treatment failure.

     

Inflammaging in cervical and lumbar degenerated intervertebral discs: analysis of proinflammatory cytokine and TRP channel expression

Purpose

To investigate and compare the occurrence of inflammatory processes in the sites of disc degeneration in the lumbar and cervical spine by a gene array and subsequent qPCR and to investigate the mechanistic involvement of transient receptor potential channels TRPC6 and TRPV4.

Methods

The gene expression of inflammatory cytokines and TRP channels was measured in human disc samples obtained from patients undergoing discectomy at the cervical (n = 24) or lumbar (n = 27) spine for degenerative disc disease (DDD) and disc herniation (DH) and analyzed for differences with regard to spinal level, IVD degeneration grade, Modic grade, age, sex, disc region and surgical extent.

Results

Aside from genes with known implication in DDD and DH, four previously unreported genes from the interferon and TRP families (IFNA1, IFNA8, IFNB1, TRPC6) could be detected. A correlation between gene expression and age (IL-15) and IVD degeneration grade (IFNA1, IL-6, IL-15, TRPC6), but not Modic grade, was identified. Significant differences were detected between cervical and lumbar discs (IL-15), nucleus and annulus (IL-6, TNF-α, TRPC6), single-level and multi-level surgery (IL-6, IL-8) as well as DDD and DH (IL-8), while sex had no effect. Multiple gene-gene pair correlations, either between different cytokines or between cytokines and TRP channels, exist in the disc.

Conclusion

This study supports the relevance of IL-6 and IL-8 in disc diseases, but furthermore points toward a possible pathological role of IL-15 and type I interferons, as well as a mechanistic role of TRPC6. With limited differences in the inflammatory profile of cervical and lumbar discs, novel anti-inflammatory or TRP-modulatory strategies for the treatment of disc pathologies may be applicable independent of the spinal region.

     

Does spinopelvic alignment affect the union status in thoracolumbar osteoporotic vertebral compression fracture?

Purpose

In the healing of osteoporotic vertebral fracture, global spinal mal-alignment might increase the load sharing at the fracture site and deteriorate the fracture healing. This study aimed to evaluate the effect of spinopelvic alignment on the union status of thoracolumbar osteoporosis-related vertebral compression fracture (OVCF).

Methods

Consecutive 48 patients with a single-level thoracolumbar fresh OVCF were treated non-operatively. Union was judged by three independent observers at 6 months, and patients were divided into union group and non-union group. Spinopelvic alignment was measured using upright whole spine radiograph before treatment as follows: pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), thoracic kyphosis (TK), sagittal vertical axis (SVA), and DSVA, defined as the distance from a plumb line dropped from the center of the C7 body to the center of fractured vertebral body.

Result

Global spinal alignment was different in union group and non-union group: SVA (4.7 ± 0.7 cm in union group vs. 8.9 ± 1.3 cm in non-union group, P = 0.007), DSVA (4.2 ± 0.6 cm in union group vs. 9.5 ± 1.0 cm in non-union group, P < 0.001), and PI–LL (18.9° ± 2.2° in union group vs. 30.3° ± 3.9° in non-union group, P = 0.014). Over 5 cm of DSVA [P = 0.022, adjusted odds 7.9 (95 % CI 1.3–77.0)] and/or over 30° of PI–LL [P = 0.026, adjusted odds 6.6 (95 % CI 1.5–44.2)] showed the significant risk factors for non-union using multivariate logistic regression analysis in the other background status.

Conclusions

Global spinal mal-alignment, showing over 5 cm of DSVA and/or over 30° of PI–LL, affected the union status of OVCF.

     

Modic changes in the adjacent vertebrae due to disc material infection with <Emphasis Type="Italic">Propionibacterium acnes</Emphasis> in patients with lumbar disc herniation

Introduction

Modic changes (MCs) in vertebral bones are induced by two mechanisms of mechanical factors and infection. As Propionibacterium acnes (P. acnes) have been reported to be associated with LBP. The aim of this study is to evaluate the MCs in patients with disc herniation and positive for P. acnes.

Methods and material

A total of 120 patients with disc herniation surgery were enrolled into the study. The samples were excised during discectomy and then cultured in both anaerobic and aerobic incubations. Gram staining was employed for investigation of all colonies. The cultured P. acnes were detected by 16S rRNA-based polymerase chain reaction (PCR). MCs of baseline MRI were evaluated.

Results

In this study, 120 subjects (69 male and 51 female) with mean age of 43.15 ± 12.62 years were investigated. Sixty disc samples and eight muscle samples were positive for microorganisms. Moreover, 16S rDNA gene was identified in 46 (38.3%) disc samples. Moreover, 36/46 patients with P. acnes in their sample had MCs.

Conclusion

According to the results and presence of 36/46 MCs in patients with lumbar disc herniation, positive for P. acnes suggests that P. acnes can lead to edema on the vertebrae endplates near to infected area.

     

A diagnostic study in patients with sciatica establishing the importance of localization of worsening of pain during coughing,sneezing and straining to assess nerve root compression on MRI

Purpose

To test whether the localization of worsening of pain during coughing, sneezing and straining matters in the assessment of lumbosacral nerve root compression or disc herniation on MRI.

Methods

Recently the diagnostic accuracy of history items to assess disc herniation or nerve root compression on magnetic resonance imaging (MRI) was investigated. A total of 395 adult patients with severe sciatica of 6–12 weeks duration were included in this study. The question regarding the influence of coughing, sneezing and straining on the intensity of pain could be answered on a 4 point scale: no worsening of pain, worsening of back pain, worsening of leg pain, worsening of back and leg pain. Diagnostic odds ratio’s (DORs) were calculated for the various dichotomization options.

Results

The DOR changed into significant values when the answer option was more narrowed to worsening of leg pain. The highest DOR was observed for the answer option ‘worsening of leg pain’ with a DOR of 2.28 (95 % CI 1.28–4.04) for the presence of nerve root compression and a DOR of 2.50 (95 % CI 1.27–4.90) for the presence of a herniated disc on MRI.

Conclusions

Worsening of leg pain during coughing, sneezing or straining has a significant diagnostic value for the presence of nerve root compression and disc herniation on MRI in patients with sciatica. This study also highlights the importance of the formulation of answer options in history taking.

     

Predictors of an unfavorable outcome 1.5 and 12 years after a first,uncomplicated lumbar disc surgery

Purpose

To identify predictors of both intermediate and long-term unfavorable outcomes after first time, uncomplicated lumbar disc surgery.

Methods

Patients (n = 120) who had undergone lumbar disc surgery were followed up 1.5 and 12 years thereafter. Baseline assessments were carried out 5–8 days after surgery. Clinical outcome was assessed in both follow-ups using the Low Back Pain Rating Scale. Statistical analysis included binary logistic and linear regression.

Results

Unfavorable outcomes were found in 50.5 % (1.5 years) and 52.6 % (12 years) of patients available for follow-up examination. Low pre-operative physical activity and severe pain in the first week after surgery were predictive of an unfavorable post-operative outcome at both follow-ups.

Conclusions

Identified predictors suggest that particular emphasis should put on comprehensive post-operative care at large and encouragement to adapt a physically active lifestyle in particular in rehabilitation concepts after first time uncomplicated lumbar disc surgery.

     

Three-dimensional analysis of volumetric changes in herniated discs of the lumbar spine: does spontaneous resorption of herniated discs always occur?

Purpose

To investigate volumetric changes in lumbar disc herniation (LDH) using three-dimensional measurements obtained by magnetic resonance imaging (MRI) and to identify possible factors affecting such changes.

Methods

Between January 2004 and December 2011, 43 patients who underwent conservative treatment for LDH were enrolled. In all, 56 disc levels were investigated. MRI was performed on two or more occasions (minimally, at the initial visit and 6 months later). The volume of each herniated disc was determined. For each patient, disc migration, morphology, initial LDH size, and clinical outcome were evaluated.

Results

The mean volumes of herniated discs at the initial and follow-up visits were 1,304.57 ± 837.99 and 993.84 ± 610.04 mm³, respectively. The mean change in volume from the initial to the follow-up visit was 310.73 ± 743.60 mm³. Volumes decreased at 35 disc levels and increased at 21 levels. The disc containment, the extent of LDH, the initial size of the herniated disc, and the degree of intactness of the posterior longitudinal ligament were significantly correlated with disc resorption and an increase in disc volume (p = 0.01, p = 0.018, p = 0.001, and p < 0.001, respectively). No significant association was evident between disc volumetric change and clinical outcome.

Conclusions

We observed that LDH is a dynamic disease and that a herniated disc is not always spontaneously resorbed, in contrast to what has been reported previously. Alleviation of clinical symptoms can be achieved via conservative treatment even if the volume of the herniated disc changes. Spinal surgeons should not only present an option of initial non-surgical treatment to LDH patients but should also inform them that the LDH may change in size during daily activity or exercise.

     

A new dynamic six degrees of freedom disc-loading simulator allows to provoke disc damage and herniation

Purpose

The cause of disc herniation is not well understood yet. It is assumed that heavy lifting and extreme postures can cause small injuries starting either in the inner anulus or from the outside close to the endplate. Such injuries are accumulated over years until its structure is weakened and finally a single loading event leads to a sudden failure of the last few intact lamellae. This paper describes a novel, custom-developed dynamic 6-DOF disc-loading simulator that allows complex loading to provoke such disc damage and herniations.

Methods

The machine’s axes are driven by six independent servomotors providing high loads (10 kN axial compression, 2 kN shear, 100 Nm torque) up to 5 Hz. A positional accuracy test was conducted to validate the machine. Subsequently, initial experiments with lumbar ovine motion segments under complex loading were performed. After testing, the discs were examined in an ultra-high field MRI (11.7 T). A three-dimensional reconstruction was performed to visualise the internal disc lesions.

Results

Validation tests demonstrated positioning with an accuracy of ≤0.08°/≤0.026 mm at 0.5 Hz and ≤0.27°/≤0.048 mm at 3.0 Hz with amplitudes of ±17°/±2 mm. Typical failure patterns and herniations could be provoked with complex asymmetrical loading protocols. Loading with axial compression, flexion, lateral bending and torsion lead in 8 specimens to 4 herniated discs, two protrusions and two delaminations. All disc failures occurred in the posterior region of the disc.

Conclusion

This new dynamic disc-loading simulator has proven to be able to apply complex motion combinations and allows to create artificial lesions in the disc with complex loading protocols. The aim of further tests is to better understand the mechanisms by which disc failure occurs at the microstructural level under different loading conditions. Visualisation with ultra-high field MRI at different time points is a promising method to investigate the gradual development of such lesions, which may finally lead to disc failure. These kinds of experiments will help to better investigate the mechanical failure of discs to provide new insights into the initiation of intervertebral disc herniation. This device will also serve for many other applications in spine biomechanics research.

     

Short-term effects of a dynamic neutralization system (Dynesys) for multi-segmental lumbar disc herniation

Purpose

To determine the safety and short-term curative effects of internal fixation using a dynamic neutralization system (Dynesys) for multi-segmental lumbar disc herniation (ms-LDH) with the control group treated by posterior lumbar interbody fusion (PLIF).

Methods

Forty-five patients with ms-LDH were selected as study group treated with Dynesys and 40 patients as control group with PLIF. The surgical efficacy was evaluated by comparing the visual analogue scale (VAS) scores, the Oswestry Disability Index (ODI) scores and the ROMs of the adjacent segment before and after surgery. The postoperative complications related to the implants were identified.

Results

All patients were followed up for an average duration of over 30 months. Dynesys stabilization resulted in significantly higher preservation of motion at the index level (p < 0.001), and significantly less (p < 0.05) hypermobility at the adjacent segments. VAS for back and leg pain and ODI improved significantly (p < 0.05) with both the methods, but there was no significant difference between the groups.

Conclusions

The non-fusion fixation system Dynesys is safe and effective regarding short-term curative effects for the treatment of ms-LDH.