Inter- and intrarater reliability of measuring lengthening of magnetically controlled growing rods on digital radiographs.

PURPOSE: The aim of this study was to determine inter- and intraobserver reliability of delta rod extension, and total rod length measured on digital x-rays in patients with early onset scoliosis (EOS) treated with magnetically controlled growing rods (MCGR). For the last decade, patients with EOS have been treated with MCGR. Replacement of MCGR relies heavily on the measurement done at every lengthening session. Only a few studies have looked at inter- and intraobserver reliability of rod lengthening, and none have used the delta extension before. METHODS: 202 radiographs presented in random order were rated and measured twice with at least a 14-day interval and differing order of the radiographs. The measuring was done at both rods. All x-rays came from 15 patients diagnosed with EOS and treated with MCGR from 2009 until 2019. The total extension length and the delta extension (the difference in total extension length between two lengthening in succession) were measured, and the intraclass correlation coefficient (ICC) calculated for both measurements RESULTS: Intrarater ICC scores varied from moderate to good, but non-significantly. Interrater reliability increased significantly from moderate (ICC 0.72 [0.68; 0.76] and 0.73 [0.69; 0.77] to excellent (ICC 0.91 [0.88; 0.93] and 0.97 [0.96: 0.98]), when examining delta extension every sixth instead of every second month. CONCLUSION: Measuring rod lengthening on x-rays can be done every 6 months, with an ample reliability. The ICC's for the delta extension with 2-3 months interval were only moderately precise, compared to the near perfect ICC's for the total extension length.

Comparison of interventions for lumbar disc herniation: a systematic review with network meta-analysis.

BACKGROUND: Implants for use in disc herniation surgery have been commercially available for some time. Several clinical trials have shown promising results. There are now a wide variety of surgical methods for treating lumbar disc herniation. PURPOSE: The objective of this systematic review was to compare all current surgical methods for disc herniation, including newer methods with implants for annulus repair and dynamic stabilization. STUDY DESIGN: Systematic review and network meta-analysis. METHODS: PRISMA-P guidelines were followed in this review. Literature search in PubMed, Embase, and Cochrane library databases identified eligible randomized controlled trials (RCT) studies comparing interventions for lumbar disc surgery. The investigated outcomes were: changes in pain score, disability score and reoperation rate with a minimum follow-up of 1 year. Risk of bias was assessed in concordance with Cochrane Neck and Back Review Group recommendation. A network meta-analysis was performed using gemtc and BUGSnet software, and each outcome evaluated using Confidence in Network Meta-Analysis (CINeMA). RESULTS: Thirty-two RCT studies, with 4,877 participants, and eight different interventions were identified. A significant difference was seen in change of pain score, as all treatments were superior to conservative treatment and percutaneous discectomy. This difference was only found to be of clinically importance when comparing conservative treatment and dynamic stabilization. There was no significant difference in reoperation rates or change in disability score, regardless of treatment. However, SUCRA plots showed a trend in ranking annulus repair and dynamic stabilization highest. Risk of bias assessment showed that 15 studies had a high overall risk of bias. Meta-regression with risk of bias as covariate did not indicate any influence in risk of bias on the model. Confidence in Network Meta-Analysis evaluation showed a high level of confidence for all treatment comparisons. CONCLUSIONS: With this network meta-analysis, we have aimed to compare all treatments for herniated lumbar disc in one large comprehensive systematic review and network meta-analysis. We have compared across the three main outcomes: disability score, pain score and reoperation rate. We were not able to rank one single treatment as the best. Most of the treatment performed at the same level. However percutaneous discectomy and conservative treatment consistently performed worse than the other treatments. In general, the CINeMA evaluation according to the GRADE recommendations gave a high level of confidence for the study comparisons.

Magnetically controlled growing rods in early-onset scoliosis.

INTRODUCTION: Early-onset scoliosis (EOS) may result in disability and a reduced life expectancy. The aim of this study was to report the results of primary magnetically controlled growing rods (MCGR) in a consecutive group of patients with EOS diagnosed and operated at Aalborg University Hospital, Denmark, from 2009 and onwards and with at least two years of follow-up. METHODS: Data were extracted from the electronic patient records and the Picture Archiving and Communication System. All data were extracted by an unbiased observer. Demographics, any complication and the Cobb angles and maximal kyphosis angles preoperatively and post-operatively were recorded. Likewise, the total expansion of the MCGR and the increase in T1-T12 and T1-S1 heights were recorded. RESULTS: A total of 15 patients (three females) were followed for an average of 3.75 years. The Cobb angles were corrected on average by 68% and the maximal kyphosis angle by 45%. The thoracic height increased significantly with only two patients (still undergoing expansions) with a T1-S1 height below 22 cm. Four complications were recorded (one deep infection and three non-functioning rods), all resulting in rod exchange. The complication rate was 27% or 0.07 per patient per year. CONCLUSIONS: The MCGR may reduce the deformity and support thoracic and pulmonary growth without any need for repeated surgeries. The number of complications in the present series was low compared with the literature with an average of 0.07 complications per year per patient or a total complication rate of 27%. FUNDING: none. TRIAL REGISTRATION: not relevant.

Temporary axial rotation stabilization for lumbar disc herniation surgery with the ARO® spinal system: a prospective analysis of safety and clinical efficacy.

BACKGROUND: Decompressive surgery has a failure rate of between 25% and 32% based on patient reported improvement in clinical symptoms. Significant back pain is associated with 53% of failures of decompressive surgery, while also being associated with abnormal axial rotation motion. We report on the clinical performance of subjects receiving a novel axial rotation stabilization implant (ARO Spinal System, ARO Medical), while undergoing a surgical decompression for a herniated lumbar disc, a condition associated with low back pain and abnormal movement. METHODS: This Danish Medicines Agency and Ethics Committee approved clinical trial prospectively investigated the use of the ARO® Spinal System as part of lumbar discectomy surgery in 20 patients. All subjects had a single level posterolateral lumbar herniation with symptoms lasting more than 6 weeks. They underwent an open discectomy at the symptomatic level, and received the implant. RESULTS: No complications with the implant were observed. Four serious adverse events not related to the devices were reported, one subject had reoperation at 3 months. Leg pain median VAS score decreased from 70 to 2 at 1 year (P=0.01) back pain median VAS score from 48 to 6 (P=0.04). Satisfaction with surgery was 88%. Oswestry Disability Index scored likewise improvement going from 38 pre-operative to 5 at 1 year. Follow-up rate was excellent 100%. CONCLUSIONS: Discectomy with the ARO Spinal System proves equally safe as a standard discectomy at 1 year follow-up. The subjects had significant improvements in both leg and back pain. In addition, they did better than historical controls, though not statistically so in this patient sample.

Biomechanical evaluation of annulus fibrosus repair with scaffold and soft anchors in an ex vivo porcine model.

INTRODUCTION: Altered biomechanical properties, due to intervertebral disc (IVD) degeneration and missing nucleus fibrosus, could be thought as one of the reasons for the back pain many herniation patients experience after surgery. It has been suggested to repair annulus fibrosus (AF) to restore stability and allow nucleus pulposus (NP) replacement and furthermore prevent reherniation. The aim of this study was to evaluate a new method for closing a defect in AF for use in herniation surgery. METHODS: Our repair method combines a polycaprolactone (PCL) scaffold plugging herniation and soft anchors to secure the plug. Ex vivo biomechanical testing was carried out in nine porcine lumbar motion segments. Flexion-extension, lateral bending and rotation were repeated three times: first in healthy specimens, second with a full thickness circular defect applied, and third time with the specimens repaired. Finally push out tests were performed to check whether the plug would remain in. RESULTS: Tests showed that applying a defect to the AF increases the range of motion (ROM), neutral zone (NZ) and neutral zone stiffness (NZS). In flexion/extension it was found significant for ROM, NZ, and NZS. For lateral bending and rotation a significant increase in ROM occurred. After AF repair ROM, NZ and NZS were normalized. All plugs remained in the AF during push out test up until 4000 N, but NP was squeezed out through the pores of the scaffold. DISCUSSION: A defect in the AF changes the biomechanical properties in the motion segment, changes that point to instability. Repairing the defect with a PCL plug and soft anchors brought the biomechanical behavior back to native state. This concept is promising and might be a viable way to repair the IVD after surgery.

Intervertebral disc degenerative changes after intradiscal injection of TNF-α in a porcine model.

PURPOSE: To investigate whether exogenous tumor necrosis factor-α (TNF-α) will initiate a degenerative process in intervertebral disc in vivo. METHODS: Exogenous TNF-α in dosages of 50 and 100 ng in 50 µL Dulbecco's Modified Essential Medium (DMEM) was injected into porcine lumbar discs; a third disc was injected only with 50 µL DMEM as a control. Magnetic resonance imaging (MRI) yielding T1- and T2-weighted images, T2-mapping, and post-contrast T1 images was performed and histology was studied as well. RESULTS: After 3 months, a significant decrease in T2 value calculated from T2-mapping MRI was observed in the annulus and nucleus of both groups injected with TNF-α along with a slight decrease in disc height and nucleus volumes in comparison to the control discs. No obvious visual differences among the groups were observed in the normal T1- and T2-weighted MRI images. Post-contrast T1 MRI showed increased annulus enhancement in both TNF-α-injected groups compared to the control discs, while no enhancement difference was observed in the nucleus. Histological analysis showed degenerative changes with annulus fissure, cell cluster, nucleus matrix loss, vascularization and interleukin-1ß expression in the outer annulus of both TNF-α-injected discs, while no degenerative changes were observed in the control discs. CONCLUSIONS: Intradiscal injection of exogenous TNF-α caused early stage disc degeneration in a porcine model. It may thus support the hypothesis of exogenic TNF-α being an important early pathogenetic factor in disc degeneration.

Interference in the endplate nutritional pathway causes intervertebral disc degeneration in an immature porcine model.

PURPOSE: Previous studies have shown that blocking the endplate nutritional pathway with bone cement did not result in obvious intervertebral disc degeneration (IDD) in mature animal models. However, there are very few comparable studies in immature animal models. As vertebroplasty currently is beginning to be applied in young, even biologically immature patients, it is important to investigate the effect of cement blocking at the endplate in an immature animal model. METHODS: Two lumbar intervertebral discs in eight immature pigs were either blocked by cement in both endplate pathways or stabbed with a scalpel in the annulus fibrosus (AF) as a positive control, and with a third disc remaining intact as a normal control. Magnetic resonance imaging (MRI) and histology study were performed. RESULTS: After three months, the cement-blocked discs exhibited severe IDD, with the percentage of disc-height index (DHI), nucleus pulposus (NP) area, and NP T2 value significantly lower than the normal control. These IDD changes were histologically confirmed. Post-contrast MRI showed diseased nutritional diffusion patterns in the cement-blocked discs. Moreover, the degenerative changes of the cement-blocked discs exceeded those of the injured AF positive controls. CONCLUSIONS: The endplate nutritional pathway was interfered with and diseased after three months of bone cement intervention in an immature porcine model. Severe interference in the endplate nutritional pathway in an immature porcine model caused IDD. These findings also draw attention to the fact that interference in endplate nutritional pathways in immature or young patients may affect the vitality of adjacent discs.