Clinical decision making in spinal fusion for chronic low back pain. Results of a nationwide survey among spine surgeons

OBJECTIVES: To assess the use of prognostic patient factors and predictive tests in clinical decision making for spinal fusion in patients with chronic low back pain. DESIGN AND SETTING: Nationwide survey among spine surgeons. PARTICIPANTS: Surgeon members of the Dutch Spine Society were questioned on their treatment strategy for chronic low back pain. PRIMARY AND SECONDARY OUTCOME MEASURES: The surgeons’ opinion on the use of prognostic factors and tests for patient selection were addressed, and the degree of uniformity was assessed. In addition, the influence of surgeon specific factors, such as clinical experience and training, was determined. RESULTS: The comments from 62 surgeons (70% response rate) were analysed. Forty-four surgeons (71%) had extensive clinical experience. There was a statistically significant lack of uniformity of opinion in 7 of the 11 items on prognostic factors and 8 of the 11 items on predictive tests, respectively. Imaging was valued much higher than predictive tests, psychological screening, or patient preferences (all p<0.01). Apart from the use of discography and long multi-segment fusions, differences in training or clinical experience did not appear to be of significant influence on treatment strategy. CONCLUSIONS: The present survey showed a lack of consensus among spine surgeons on the use of predictive tests for patient selection. Prognostic patient factors were not consistently incorporated in their treatment strategy. Clinical decision making for spinal fusion to treat chronic low back pain does not have a uniform evidence base in practice. Future research should focus on identifying subgroups of patients for whom spinal fusion is an effective treatment. Only a reliable prediction of surgical outcome, combined with the implementation of individual patient factors, may enable the instalment of consensus guidelines in surgical decision making for chronic low back pain

Minimally Invasive versus Classic Procedures in Total Hip Arthroplasty: A Double-blind Randomized Controlled Trial

BACKGROUND: For total hip arthroplasty (THA), minimally invasive surgery (MIS) uses a smaller incision and less muscle dissection than the classic approach (CLASS), and may lead to faster rehabilitation. QUESTIONS/PURPOSES: Does minimally invasive hip arthroplasty result in superior clinical outcomes? PATIENTS AND METHODS: In this double-blind randomized controlled trial, 120 consecutive primary noncemented THAs in 120 patients were assigned to one of two groups (MIS or CLASS). The randomization sequence was stratified for two groups of surgeons, ie, those using a posterolateral approach (PL-CLASS or PL-MIS) and those using an anterolateral approach (AL-CLASS or AL-MIS). Length of the incisions was 18 cm for the CLASS procedures. MIS incisions were extended at the skin level to 18 cm at the end of the procedure. The primary end point was the Harris hip score (HHS) at 6 weeks postoperatively. Patient-centered questionnaires were obtained preoperatively and after 6 weeks and 1 year. RESULTS: For the patients in the MIS group (average 7.8 cm incision length), statistically significant increased mean HHSs were seen compared with the CLASS group at 6 weeks and 1 year. This difference was small and mainly caused by the favorable results of the PL-MIS. In the MIS group, surgical time was longer. A learning curve was observed based on operation time and complication rate. Although not statistically significant, the perioperative complication rate was rather high in the (anterolateral) MIS group. CONCLUSIONS: The minimal invasive approach in THA did not show a clinically relevant superior outcome in the first postoperative year. LEVEL OF EVIDENCE: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidenc

Automatic generation of subject-specific finite element models of the spine from magnetic resonance images

The generation of subject-specific finite element models of the spine is generally a time-consuming process based on computed tomography (CT) images, where scanning exposes subjects to harmful radiation. In this study, a method is presented for the automatic generation of spine finite element models using images from a single magnetic resonance (MR) sequence. The thoracic and lumbar spine of eight adult volunteers was imaged using a 3D multi-echogradient-echo sagittal MR sequence. A deep-learning method was used to generate synthetic CT images from the MR images. A pre-trained deeplearning network was used for the automatic segmentation of vertebrae from the synthetic CT images. Another deep-learning network was trained for the automatic segmentation of intervertebral discs from the MR images. The automatic segmentations were validated against manual segmentations for two subjects, one with scoliosis, and another with a spine implant. A template mesh of the spine was registered to the segmentations in three steps using a Bayesian coherent point drift algorithm. First, rigid registration was applied on the complete spine. Second, non-rigid registration was used for the individual discs and vertebrae. Third, the complete spine was non-rigidly registered to the individually registered discs and vertebrae. Comparison of the automatic and manual segmentations led to dice-scores of 0.93–0.96 for all vertebrae and discs. The lowest dice-score was in the disc at the height of the implant where artifacts led to under-segmentation. The mean distance between the morphed meshes and the segmentations was below 1 mm. In conclusion, the presented method can be used to automatically generate accurate subject-specific spine models

Three-dimensional correction of scoliosis by a double spring reduction system as a dynamic internal brace:a pre-clinical study in Göttingen minipigs

BACKGROUND CONTEXT: Adolescent idiopathic scoliosis (AIS) is a major skeletal deformity that is characterized by a combination of apical rotation, lateral bending and apical lordosis. To provide full 3D correction, all these deformations should be addressed. We developed the Double Spring Reduction (DSR) system, a (growth-friendly) concept that continuously corrects the deformity through two different elements: A posterior convex Torsional Spring Implant (TSI) that provides a derotational torque at the apex, and a concave Spring Distraction System (SDS), which provides posterior, concave distraction to restore thoracic kyphosis. PURPOSE: To determine whether the DSR components are able to correct an induced idiopathic-like scoliosis and to compare correction realized by the TSI alone to correction enforced by the complete DSR implant. STUDY DESIGN/SETTING: Preclinical randomized animal cohort study. PATIENT SAMPLE: Twelve growing Göttingen minipigs. OUTCOME MEASURES: Coronal Cobb angle, T10-L3 lordosis/kyphosis, apical axial rotation, relative anterior lengthening. METHODS: All mini-pigs received the TSI with a contralateral tether to induce an idiopathic-like scoliosis with apical rotation (mean Cobb: 20.4°; mean axial apical rotation: 13.1°, mean lordosis: 4.9°). After induction, the animals were divided into two groups: One group (N=6) was corrected by TSI only (TSI only-group), another group (N=6) was corrected by a combination of TSI and SDS (DSR-group). 3D spinal morphology on CT was compared between groups over time. After 2 months of correction, animals were euthanized. RESULTS: Both intervention groups showed excellent apical derotation (TSI only-group: 15.0° to 5.4°; DSR-group: 11.2° to 3.5°). The TSI only-group showed coronal Cobb improvement from 22.5° to 6.0°, while the DSR-group overcorrected the 18.3° Cobb to -9.2°. Lordosis was converted to kyphosis in both groups (TSI only-group: -4.6° to 4.3°; DSR-group: -5.2° to 25.0°) which was significantly larger in the DSR-group (p<.001). CONCLUSIONS: The TSI alone realized strong apical derotation and moderate correction in the coronal and sagittal plane. The addition of distraction on the posterior concavity resulted in more coronal correction and reversal of induced lordosis into physiological kyphosis. CLINICAL SIGNIFICANCE: This study shows that dynamic spring forces could be a viable method to guide the spine towards healthy alignment, without fusing it or inhibiting its growth

Health-related quality of life in early onset scoliosis patients treated with the spring distraction system:what to expect in the first 2 years after surgery

Purpose: The Spring Distraction System (SDS) is a novel “growth-friendly” implant for the treatment of Early-Onset Scoliosis (EOS). This prospective study aims to determine the evolution of the “24-Item Early-Onset Scoliosis Questionnaire” (EOSQ-24) scores during 2-year follow-up after SDS surgery. Secondary aims include investigating the relation between EOSQ-24 scores and EOS etiology, and evaluating the impact of an unplanned return to the operating room (UPROR) on HRQoL. Methods: All SDS patients with at least 2-year follow-up were included. Caregivers completed the EOSQ-24 pre-operatively, post-operatively, and at 6, 12, and 24 month follow-up. Mean total and -domain scores were graphed over time. Repeated-measures ANOVA analyzed the influence of etiology on EOSQ-24 scores. Multiple regression analyzed associations between UPRORs and EOSQ-24 scores. Results: Forty-nine patients were included. Mean total EOSQ-24 scores decreased from 70 pre-operatively to 66 post-operatively, then gradually increased to 75 (24 months). Most domains exhibited changes over time, with initial declines, but eventually surpassing pre-operative levels after 2-year follow-up. Neuromuscular/Syndromic patients had lower scores, but showed similar improvements over time compared with other etiologies. Multiple regression showed lower Parental Burden domain score (− 14 points) in patients with UPRORs, although no significant reductions were found in total score, or in other domains. Conclusion: HRQoL decreases immediately following SDS surgery but quickly recovers and exceeds pre-operative levels at 2-year follow-up in all domains. Neuromuscular/Syndromic patients have lower initial scores, but progress similarly over time. UPRORs do not influence EOSQ-24 scores, except for a negative impact on the Parental Burden domain in the short term. Level of Evidence: III.</p

Deep learning-enabled MRI-only photon and proton therapy treatment planning for paediatric abdominal tumours

Purpose: To assess the feasibility of magnetic resonance imaging (MRI)-only treatment planning for photon and proton radiotherapy in children with abdominal tumours. Materials and methods: The study was conducted on 66 paediatric patients with Wilms' tumour or neuroblastoma (age 4 +/- 2 years) who underwent MR and computed tomography (CT) acquisition on the same day as part of the clinical protocol. MRI intensities were converted to CT Hounsfield units (HU) by means of a UNet-like neural network trained to generate synthetic CT (sCT) from T1- and T2-weighted MR images. The CT-to-sCT image similarity was evaluated by computing the mean error (ME), mean absolute error (MAE), peak signal-to-noise ratio (PSNR) and Dice similarity coefficient (DSC). Synthetic CT dosimetric accuracy was verified against CT-based dose distributions for volumetric-modulated arc therapy (VMAT) and intensity-modulated pencil-beam scanning (PBS). Relative dose differences (D-diff) in the internal target volume and organs-at-risk were computed and a three-dimensional gamma analysis (2 mm, 2%) was performed. Results: The average +/- standard deviation ME was -5 +/- 12 HU, MAE was 57 +/- 12 HU, PSNR was 30.3 +/- 1. 6 dB and DSC was 76 +/- 8% for bones and 92 +/- 9% for lungs. Average D-diff were 99% (range [85; 100]%) for VMAT and >96% (range [87; 100]%) for PBS. Conclusion: The deep learning-based model generated accurate sCT from planning T1w- and T2w-MR images. Most dosimetric differences were within clinically acceptable criteria for photon and proton radiotherapy, demonstrating the feasibility of an MRI-only workflow for paediatric patients with abdominal tumours. (C) 2020 The Authors. Published by Elsevier B.V

Patient‐specific 3D‐printed shelf implant for the treatment of hip dysplasia: anatomical and biomechanical outcomes in a canine model

A solution for challenging hip dysplasia surgery could be a patient-specific 3D-printed shelf implant that is positioned extra-articular and restores the dysplastic acetabular rim to normal anatomical dimensions. The anatomical correction and biomechanical stability of this concept were tested in a canine model that, like humans, also suffers from hip dysplasia. Using 3D reconstructed computed tomography images the 3D shelf implant was designed to restore the radiological dysplastic hip parameters to healthy parameters. It was tested ex vivo on three dog cadavers (six hips) with hip dysplasia. Each hip was subjected to a biomechanical subluxation test, first without and then with the 3D shelf implant in place. Subsequently, an implant failure test was performed to test the primary implant fixation. At baseline, the dysplastic hips had an average Norberg angle of 88 ± 3° and acetabular coverage of 47 ± 2% and subluxated at an average of 83 ± 2° of femoral adduction. After adding the patient-specific shelf implants the dysplastic hips had an average Norberg angle of 122 ± 2° and acetabular coverage of 67 ± 3% and subluxated at an average of 117 ± 2° of femoral adduction. Implant failure after primary implant fixation occurred at an average of 1330 ± 320 Newton. This showed that the patient-specific shelf implants significantly improved the coverage and stability of dysplastic hips in a canine model with naturally occurring hip dysplasia. The 3D shelf is a promising concept for treating residual hip dysplasia with a straightforward technology-driven approach; however, the clinical safety needs to be further investigated in an experimental proof-of-concept animal study

Spinal decompensation in degenerative lumbar scoliosis

Due to the aging population, degenerative scoliosis is a growing clinical problem. It is associated with back pain and radicular symptoms. The pathogenesis of degenerative scoliosis lies in degenerative changes of the spinal structures, such as the intervertebral disc, the facet joints and the vertebrae itself. Possibly muscle weakness also plays a role. However, it is not clear what exactly causes the decompensation to occur and what determines the direction of the curve. It is known that in the normal spine a pre-existing rotation exists at the thoracic level, but not at the lumbar level. In this retrospective study we have investigated if a predominant curve pattern can be found in degenerative scoliosis and whether symptoms are predominantly present at one side relative to the curve direction. The lumbar curves of 88 patients with degenerative scoliosis were analyzed and symptoms were recorded. It was found that curve direction depended significantly on the apical level of the curve. The majority of curves with an apex above L2 were convex to the right, whereas curves with an apex below L2 were more frequently convex to the left. This would indicate that also in degenerative scoliosis the innate curvature and rotational pattern of the spine plays a role in the direction of the curve. Unilateral symptoms were not coupled to the curve direction. It is believed that the symptoms are related to local and more specific degenerative changes besides the scoliotic curve itself

Long-term psychosocial functioning after Ilizarov limb lengthening during childhood: 37 patients followed for 2–14 years

Background and purpose Few studies have been concerned with the patient's perception of the outcome of limb lengthening. We describe the psychological and social functioning after at least 2 years of follow-up in patients who had had a leg length discrepancy and who had undergone an Ilizarov limb lengthening procedure

Intradiscal injection of human recombinant BMP-4 does not reverse intervertebral disc degeneration induced by nuclectomy in sheep

Background: Intervertebral disc (IVD) degeneration is suggested as a major cause of chronic low back pain (LBP). Intradiscal delivery of growth factors has been proposed as a promising strategy for IVD repair and regeneration. Previously, BMP-4 was shown to be more potent in promoting extracellular matrix (ECM) production than other BMPs and TGF-β in human nucleus pulposus (NP) cells, suggesting its applicability for disc regeneration. Methods: The effects of BMP-4 on ECM deposition and cell proliferation were assessed in sheep NP and annulus fibrosus (AF) cells in a pellet culture model. Further, a nuclectomy induced sheep lumbar IVD degeneration model was used to evaluate the safety and effects of intradiscal BMP-4 injection on IVD regeneration. Outcomes were assessed by magnetic resonance imaging, micro-computed tomography, histological and biochemical measurements. Results: In vitro, BMP-4 significantly increased the production of proteoglycan and deposition of collagen type II and proliferation of NP and AF cells. Collagen type I deposition was not affected in NP cells, while in AF cells it was high at low BMP-4 concentrations, and decreased with increasing concentration of BMP-4. Intradiscal injection of BMP-4 induced extradiscal new bone formation and Schmorl's node-like changes in vivo. No regeneration in the NP nor AF was observed. Conclusion: Our study demonstrated that although BMP-4 showed promising regenerative effects in vitro, similar effects were not observed in a large IVD degeneration animal model. The Translational Potential of This Article: The contradictory results of using BMP-4 on IVD regeneration between in vitro and in vivo demonstrate that direct BMP-4 injection for disc degeneration-associated human chronic low back pain should not be undertaken. In addition, our results may also shed light on the mechanisms behind pathological endplate changes in human patients as a possible target for therapy