Patient-reported outcome from minimal invasive surgery compared with conventional open surgery for thoracolumbar fractures of the spine.

Study design: retrospective cohort study of prospectively collected data. Objective: The treatment guidelines for thoracolumbar spinal fractures are controversial although minimally invasive surgery (MIS) is a popular alternative to the traditional open approach (TOA). Limited data exists about outcomes after MIS fracture treatment. The main aim of our study was to evaluate self-reported disability, health-related quality of life, pain, and satisfaction after MIS compared with TOA. Methods: Of 173 patients operated from 2014 to 2018, 64.7% patients completed the Oswestry Disability Index (ODI), the EQ-5D-5L, and a tailored clinical follow-up questionnaire on employment status, pain, activity level, and satisfaction with treatment. Results: Of the 112 patients, 34 had MIS and 78 had TOA. Mean follow-up was 56 months. The two groups were comparable on demographic variables apart from mean age - MIS group was 10 years older. The MIS group had better ODI scores (p = 0.046), but the groups were similar regarding return to work and disability retirement. The EQ-5D-5L index for the MIS were very close (mean -0.033, median +0.049) to the Danish population score, while the TOA showed a greater deviation (mean - 0.125, median -0.040). The MIS used less pain medication than the TOA. Both groups were similarly satisfied with treatment results. Conclusion: Our data indicates that MIS surgery for thoracolumbar spinal fractures can achieve acceptable self-reported outcomes in terms of disability, health-related quality of life, pain, and satisfaction with treatment. However, a randomized controlled trial is needed to determine whether the MIS approach is superior to TOA.

Efficacy of bioreactor-activated bone substitute with bone marrow nuclear cells on fusion rate and fusion mass microarchitecture in sheep.

Bioreactors have been used for bone graft engineering in pre-clinical investigations over the past 15 years. The ability of bioreactor-incubated bone marrow nuclear cells (BMNCs) to enhance bone-forming potential varies significantly, and the three-dimensional (3D) distribution of BMNCs within the scaffold is largely unknown. The aims of this study were (1) to investigate the efficacy of a carbonated hydroxyapatite (CHA) with/without BMNCs on spine fusion rate and fusion mass microarchitecture using a highly challenging two-level posterolateral spine fusion without instrumentation; and (2) to evaluate 3D distribution of BMNCs within scaffolds characterized by immunohistochemistry. Fusion rate and fusion mass were quantified by micro-CT, microarchitectural analysis, and histology. While the homogenous 3D distribution of BMNCs was not observed, BMNCs were found to migrate towards a substitute core. In the autograft group, the healing rate was 83.3%, irrespective of the presence of BMNCs. In the CHA group, also 83.3% was fused in the presence of BMNCs, and 66.7% fused without BMNCs. A significant decrease in the fusion mass porosity (p = .001) of the CHA group suggested the deposition of mineralized bone. The autograft group revealed more bone, thicker trabeculae, and better trabecular orientation but less connection compared to the CHA group. Immunohistochemistry confirmed the ability of bioreactors to incubate a large-sized substitute coated with viable BMNCs with the potential for proliferation and differentiation. These findings suggested that a bioreactor-activated substitute is comparable to autograft on spine fusion and that new functional bone regeneration could be achieved by a combination of BMNCs, biomaterials, and bioreactors.

Axial plane characteristics of thoracic scoliosis and their usefulness for determining the fusion levels and the correction technique.

PURPOSE: There is insufficient information regarding axial plane characteristics of scoliosis despite its 3D nature. The posterior-anterior vertebral vector (VV) has been proposed to characterize the axial plane appearances of the thoracic scoliosis. This study aimed to highlight the importance of knowledge of axial plane features when determining fusion levels and correction techniques of thoracic curves. METHODS: Altogether, 233 thoracic curves were analyzed using the VV after proving its usability instead of 3D angles to determine axial plane parameters such as apical vertebral (APV) axial rotations, APV lateral displacement, and intervertebral rotations (IVR). K-means clustering and regression analysis were used to identify axial plane curve patterns and determine the relationship between the coronal angles and axial plane characteristics, respectively. RESULTS: A close correlation was found between 3D angles and VV projected angles. Eight axial plane clusters were distinct, exhibiting different lateral APV displacement toward the interacetabular axis with relatively small axial rotations and a simultaneous decrease in sagittal curves. The regression analysis showed that the correlation of coronal curve magnitude was significantly stronger (r = 0.78) with APV lateral translation than with APV axial rotation (r = 0.65). CONCLUSION: Based on these findings, the primary goal of scoliosis correction should focus on minimizing lateral translation rather than eliminating axial rotation. Knowing the IVR in the axial plane helps accurately determine the limits of the structural curves. VV-based axial views can facilitate the accurate determination of the end vertebrae and selection of the appropriate correction technique of the curve. These slides can be retrieved under Electronic Supplementary Material.

Providence nighttime bracing is effective in treatment for adolescent idiopathic scoliosis even in curves larger than 35°.

Since 2006, the Providence nighttime brace has been used for a conservative treatment for scoliosis. Previous studies comparing the outcomes after full-time bracing and nighttime bracing have reported a comparable outcome with curves < 35°. The aim of this study was to report the outcome after treatment in a cohort of adolescent idiopathic scoliosis patients, with curves between 20° and 45°. METHODS: One hundred and twenty-four patients with adolescent idiopathic scoliosis were included in this study with Cobb > 20°, remaining growth potential and no previous scoliosis treatment. Providence nighttime treatment, 8 h nightly, was initiated. Treatment was continued until 2 years post-menarcheal for females and until 6-month growth arrest for males. The patients were evaluated using standing radiographs during treatment and 6 and 12 months after termination of bracing. RESULTS: One hundred and twenty-four patients were included; 80 patients terminated brace treatment and were available for follow-up. Mean in-brace correction was 82%, and curve progression was observed in 9 patients. Brace treatment was success full in 89% of the patients, 88% of the patients braced with curves 20°-29°, 93% of the patients braced with 30°-39° and 77% of the patients braced with curves 40°-45°. Five of the 80 AIS patients were referred to surgery: 4 due to progression and 1 due to cosmetic concerns. CONCLUSIONS: Providence nighttime braces are an effective treatment for adolescent idiopathic scoliosis patients. This study reports a success rate of 89%, and the results are comparable to full-time treatment with the Boston brace. In-brace correction is crucial in part-time bracing, and we recommend at least 70% curve correction, if part-time bracing should be considered. These slides can be retrieved under Electronic Supplementary Material.

Comparison of synthetic bone graft ABM/P-15 and allograft on uninstrumented posterior lumbar spine fusion in sheep.

BACKGROUND: Spinal fusion is a commonly used procedure in spinal surgery. To ensure stable fusion, bone graft materials are used. ABM/P-15 (commercial name i-Factor™ Flex) is an available synthetic bone graft material that has CE approval in Europe. This peptide has been shown to improve bone formation when used in devices with fixation or on bone defects. However, the lack of external stability and large graft size make posterolateral lumbar fusion (PLF) a most challenging grafting procedure. This prospective randomized study was designed to evaluate early spinal fusion rates using an anorganic bovine-derived hydroxyapatite matrix (ABM) combined with a synthetic 15 amino acid sequence (P-15)-ABM/P-15 bone graft, and compared with allograft in an uninstrumented PLF model in sheep. The objective of this study was to assess fusion rates when using ABM/P-15 in uninstrumented posterolateral fusion in sheep. METHODS: Twelve Texas/Gotland mixed breed sheep underwent open PLF at 2 levels L2/L3 and L4/L5 without fixation instruments. The levels were randomized so that sheep received an ABM graft either with or without P15 coating. Sheep were euthanized after 4.5 months and levels were harvested and evaluated with a micro-CT scanner and qualitative histology. Fusion rates were assessed by 2D sections and 3D reconstruction images and fusion was defined as intertransverse bridging. RESULTS: There was 68% fusion rate in the allograft group and an extensive migration of graft material was noticed with a fusion rate of just 37% in the ABM/P-15 group. Qualitative histology showed positive osteointegration of the material and good correlation to scanning results. CONCLUSIONS: In this PLF fusion model, ABM/P15 demonstrated the ability to migrate when lacking external stability. Due to this migration, reported fusion rates were significantly lower than in the allograft group. The use of ABM/P15 as i-Factor™ Flex may be limited to devices with fixation and bone defects.

Effects of a perfusion bioreactor activated novel bone substitute in spine fusion in sheep.

PURPOSE: To evaluate the effect of a large perfusion-bioreactor cell-activated bone substitute, on a two-level large posterolateral spine fusion sheep model. METHODS: A 50 mm long porous biphasic-calcium-phosphate bone substitute reinforced with poly(D,L-lactide) and, activated with bone marrow derived mononuclear-cells (BMNC) was used. Eighteen sheep were divided into two groups and one group (n = 9) had BMNC-activated bone substitutes and cell-free substitutes implanted. The second group (n = 9) had autograft supplemented with BMNC and regular autograft implanted. The implant material was alternated between spine level L2-L3 and L4-L5 in both groups. MicroCT was used to compare the spine fusion efficacy and bone structure of the two groups as well as the implanted bone substitutes and non-implanted substitutes. RESULTS: After 4½ months six sheep survived in both groups and we found five spine levels were fused when using activated bone substitute compared to three levels with cell-free bone substitute (p = 0.25). Five sheep fused at both levels in the autograft group. A significant increased bone density (p < 0.05) and anisotropy (p < 0.05) was found in the group of activated bone substitutes compared to cell-free bone substitute and no difference existed on the other parameters. The implanted bone substitutes had a significant higher bone density and trabecular thickness than non-implanted bone substitutes, thus indicating that the PLA reinforced BCP had osteoconductive properties (p < 0.05). No effect of the supplemented BMNC to autograft was observed. The autograft group had a significant higher bone density, trabecular thickness and degree of anisotropy than the implanted bone substitutes (p < 0.05), but a lower connectivity density existed (p < 0.05). This indicates that though the activated substitute might have a similar fusion efficacy to autograft, the fusion bridge is not of equal substance. CONCLUSION: We found that bioreactor-generated cell-based bone substitutes seemed superior in fusion ability when compared to cell-free bone substitute and comparable to autograft in fusion ability, but not in bone structure. This combined with the favorable biocompatible abilities and strength comparable to human cancellous bone indicates that it might be a suitable bone substitute in spine fusion procedures.

[Iatrogenic dural lesions in lumbar neural decompressive surgery]. / Iatrogene duralaesioner ved dekompressionskirurgi i lumbalcolumna.

INTRODUCTION: Iatrogenic dural tear with cerebrospinal fluid leakage is a known complication of lumbar surgery of the columna. In the literature, the incidence is 3-16%. MATERIAL AND METHODS: The study was a retrospective, consecutive review of electronic patient records after spinal surgery at the Private Hospital Hamlet. The study covers cases from the 10-month period from September 1, 2007 to June 30, 2008. Data was collected after this period and consists of surgeon-documented dural tears. At the time of surgery, the surgeon was unaware that there would be a subsequent registration. A total of 634 patients had lumbar neural decompressive surgery - 479 patients were treated for spinal stenosis and 155 for prolapsed disc. RESULTS: The incidence of dural tear was 3.9% (25 dural tears in 634 operations). The risk of a dural tear after secondary surgery was 7.9% versus 3.3% for primary (p = 0.02) and the mean age was 65.9 years for patients with dural tear compared with 58.1 years for patients without (p = 0.00). The difference in the mean duration of surgery was significant being 72 minutes in the group suffering a dural tear compared with 56 minutes (p = 0.03) among the remaining patients, and in the former group length of stay was increased by 1.1 day (p = 0.00). CONCLUSION: The incidence of iatrogenic dural tear was 3.9%. The incidence of dural tear was doubled in secondary surgery. The duration of surgery increased by 16 minutes and the patients with dural tear were also hospitalized one day longer.

[Percutaneous vertebroplasty with only few complications--a retrospective study]. / Perkutan vertebroplastik med kun få komplikationer--et retrospektivt studie.

INTRODUCTION: Percutaneous vertebroplasty (PVP) was introduced in 1984 and has proved to be valuable in the treatment of painful vertebral lesions such as haemangiomas, metastasis, and osteoporotic fractures. According to the literature, the operation provides pain relief with only few and harmless complications. The aim of this study was to evaluate our perioperative experiences with special reference to the safety of the procedure. MATERIAL AND METHODS: A total of 156 procedures were performed in 148 patients with osteoporotic fractures. Both acute and chronic fractures were treated. All patients had plain radiographs of the spine. Magnetic resonance imaging (MRI) or bone scans were performed in case of old fractures or more than one fracture in patients with acute back-pain. At follow-up after three and 12 months, plain radiographs were performed in conjunction with physical examinations and interviews. Data were collected retrospectively. RESULTS: We identified 40.4% cemental leaks (confidence interval (CI) 32.6; 48.5). None of these resulted in neurological symptoms. One patient experienced shortness of breath after the procedure, one had atrial fibrillation, and one patient had an iatrogenic pneumothorax. In all, the frequency of symptomatic complications was 1.9% (CI -0.4; 5.5). CONCLUSION: We believe that PVP is a safe procedure with only few symptomatic complications when performed under local anaesthesia and by a specialist in transpedicular approach.

Percutaneous vertebroplasty compared to conservative treatment in patients with painful acute or subacute osteoporotic vertebral fractures: three-months follow-up in a clinical randomized study.

STUDY DESIGN: Clinical randomized study. OBJECTIVE: The aim of this study is to compare percutaneous vertebroplasty (PVP) to conservative treatment of patients with osteoporotic vertebral fractures in a clinical randomized study with respect to pain, physical and mental outcome, and to asses the risk of adjacent fractures. SUMMARY OF BACKGROUND DATA: PVP is a therapeutic procedure performed to reduce pain in vertebral lesions. Despite the lack of comparative randomized clinical trials PVP is generally seen as a safe and efficient procedure for painful osteoporotic fractures. METHODS: Fifty patients (41 females) were included from January 2001 until January 2008. Patients with acute (<2 weeks) and subacute (between 2 and 8 weeks) osteoporotic fractures were included and randomized to either PVP or conservative treatment. Pain was assessed with a visual analogue scale and physical and mental outcome were assessed by validated questionnaires and tests. Tests, questionnaires, and plain radiographs were performed at the inclusion and after 3 months. RESULTS: Reduction in pain from initial visit to 3-month follow-up was comparable in the 2 groups (P = 0.33) from approximate visual analogue scale 8.0 to visual analogue scale 2.0, intragroup difference was significant (P = 0.00). Reduction in pain in the PVP group was immediate 12 to 24 hours after the procedure (P = 0.00). There was no significant difference in the other parameters when comparing the results at inclusion and after 3 months within both groups and between the groups after 3 months with a few exceptions. We observed 2 adjacent fractures in the PVP group and non in the conservative group. CONCLUSION: The majority of patients with acute or subacute painful osteoporotic compression fractures in the spine will recover after a few months of conservative treatment. The risk of adjacent fractures needs further research. No major adverse events were observed.