Purposes And Background. Having found a significant limitation of neural movement (66.6%) during SLR performed on the symptomatic side in patients with sub-acute lumbar intervertebral disc herniation (LIDH), we followed up on the same patients over 1.5 years to ascertain if changes in cord excursion accompany changes in clinical symptoms. Methods. 14 patients, who originally had sciatic symptoms due to subacute LIDH, were re-assessed both clinically and radiologically with a 1.5T magnetic resonance (MR) scanner. Displacement of the conus medullaris during the unilateral and bilateral SLR was quantified reliably with a randomized procedure and compared between maneuvers and with data from baseline. Multivariate regression models and backward variable selection method were employed to identify variables more strongly associated with decrease in low back pain and radicular symptoms. Results. Compared to previously presented baseline values, the data showed an extensive increase in neural sliding of 323.4% (2.52mm, p≤0.001) with the symptomatic SLR, 37.1% (0.82mm, p=0.0058) with asymptomatic SLR, and 48.2% (1.64mm, p≤0.001) with the bilateral SLR. Increase in neural sliding correlated significantly with decrease of both radicular symptoms (Pearson=−0.719, p≤0.001) and low back pain (Pearson=−0.693, p≤0.001). Multivariate regression models and backward variable selection method confirmed that 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 non-invasive data to objectively support the association between increase in magnitude of neural adaptive movement and decrease in clinical symptoms in in-vivo and structurally intact human subjects. No conflicts of interest. Sources of funding: This research was partly funded by Finnish National VTR Grant for Medical Research, grant number 128/2012

We studied 23 patients with spondylolysis of the fifth lumbar vertebra (L5) and 20 with spondylolytic spondylolisthesis at this level. All were more than 40 years of age. The transverse processes at L5 were significantly wider in the former group than in the latter. We also dissected 56 cadavers to study the morphological relationship between the transverse process of L5 and the iliolumbar ligament, and found that the wider transverse process is associated with increased width of the posterior band of the iliolumbar ligament. If a patient with pars defects has wide transverse processes at L5, the lumbosacral junction may be stabilised by wide posterior bands of the iliolumbar ligament and the fifth lumbar vertebra by the ligament, preventing anterior displacement

Objectives. Understanding lumbar facet joint involvement and biomechanical changes post spinal fusion is limited. This study aimed to establish an in vitro model assessing mechanical effects of fusion on human lumbar facet joints, employing synchronized motion, pressure, and stiffness analysis. Methods and Results. Seven human lumbar spinal units (age 54 to 92, ethics 15/YH/0096) underwent fusion via a partial nucleotomy model mimicking a lateral cage approach with PMMA cement injection. Mechanical testing pre and post-fusion included measuring compressive displacement and load, local motion capture, and pressure mapping at the facet joints. pQCT imaging (82 microns isotropic) was carried out at each stage to assess the integrity of the vertebral endplates and quantify the amount of cement injected. Before fusion, relative facet joint displacement (6.5 ± 4.1 mm) at maximum load (1.1 kN) exceeded crosshead displacement (3.9 ± 1.5 mm), with loads transferred across both facet joints. After fusion, facet displacement (2.0 ± 1.2 mm) reduced compared to pre-fusion, as was the crosshead displacement (2.2 ± 0.6 mm). Post-fusion loads (71.4 ± 73.2 N) transferred were reduced compared to pre-fusion levels (194.5 ± 125.4 N). Analysis of CT images showed no endplate damage post-fusion, whilst the IVD tissue: cement volume ratio did not correlate with the post-fusion behaviour of the specimens. Conclusion. An in vitro model showed significant facet movement reduction with stand-alone interbody cage placement. This technique identifies changes in facet movement post-fusion, potentially contributing to subsequent spinal degeneration, highlighting its utility in biomechanical assessment. Conflicts of interest. None. Sources of funding. This work was funded by EPSRC, under grant EP/W015617/1

Introduction. Vertebral compression fractures are the most common type of osteoporotic fracture. Though 89% of clinical fractures occur anteriorly, it is challenging to replicate these ex vivo with the underlying intervertebral discs (IVDs) present. Furthermore, the role of disc degeneration in this mechanism is poorly understood. Understanding how disc morphology alters vertebral strain distributions may lead to the utilisation of IVD metrics in fracture prediction, or inform surgical decision-making regarding instrumentation type and placement. Aim. To determine the effect of disc degeneration on the vertebral trabecular bone strain distributions in axial compression and flexion loading. Methods. Eight cadaveric thoracolumbar segments (T11-L3) were prepared (N=4 axial compression, N=4 flexion). µCT-based digital volume correlation was used to quantify trabecular strains. A bespoke loading device fixed specimens at the resultant displacement when loaded to 50N and 800N. Flexion was achieved by adding 6° wedges. Disc degeneration was quantified with Pfirrmann grading and T2 relaxation times. Results. Anterior axial strains were 80.9±39% higher than the posterior region in flexion (p<0.01), the ratio of which was correlated with T2 relaxation time (R. 2. =0.80, p<0.05). In flexion, the central-to-peripheral axial strain ratio in the endplate region was significantly higher when the underlying IVDs were non-degenerated relative to degenerated (+38.1±12%, p<0.05). No significant differences were observed in axial compression. Conclusion. Disc degeneration is a stronger determinant of the trabecular strain distribution when flexion is applied. Load transfer through non-degenerate IVDs under flexion appears to be more centralised, suggesting that disc degeneration predisposes flexion-type compression fractures by shifting high strains anteriorly. Conflicts of interest. The authors declare none. Sources of funding. This work was funded by the Engineering & Physical Sciences Research Council (EP/V029452/1), and Back-to-Back

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The aim of this study was to assess the accuracy of pedicle screw placement, as well as intraoperative factors, radiation exposure, and complication rates in adult patients with degenerative disorders of the thoracic and lumbar spines who have undergone robotic-navigated spinal surgery using a contemporary system.

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This systematic review aims to identify 3D predictors derived from biplanar reconstruction, and to describe current methods for improving curve prediction in patients with mild adolescent idiopathic scoliosis.

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The aim of this study was to reassess the rate of neurological, psoas-related, and abdominal complications associated with L4-L5 lateral lumbar interbody fusion (LLIF) undertaken using a standardized preoperative assessment and surgical technique.

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The optimal procedure for the treatment of ossification of the posterior longitudinal ligament (OPLL) remains controversial. The aim of this study was to compare the outcome of anterior cervical ossified posterior longitudinal ligament en bloc resection (ACOE) with posterior laminectomy and fusion with bone graft and internal fixation (PTLF) for the surgical management of patients with this condition.

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Anchorage of pedicle screw rod instrumentation in the elderly spine with poor bone quality remains challenging. Our study aims to evaluate how the screw bone anchorage is affected by screw design, bone quality, loading conditions, and cementing techniques.

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To study the associations of lumbar developmental spinal stenosis (DSS) with low back pain (LBP), radicular leg pain, and disability.

We treated 183 patients with fractures of the odontoid process (109 type II, 74 type III) non-operatively. Union was achieved in 59 (54%) with type-II fractures. All type-III fractures united, but in 16 patients union was delayed. There was no correlation between union and the clinical or radiological outcome of the fractures. Selective vertebral angiography, carried out in 18 patients ten with acute fractures and eight with nonunion, showed that the blood supply to the odontoid process was not disrupted. Studies on ten adult axis vertebrae at post-mortem showed that the difference in the surface area between type-II and type-III fractures was statistically significant. Our findings show that an age of more than 40 years, anterior displacement of more than 4 mm, posterior displacement and late presentation contribute towards nonunion of type-II fractures

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To determine the effectiveness of prone traction radiographs in predicting postoperative slip distance, slip angle, changes in disc height, and lordosis after surgery for degenerative spondylolisthesis of the lumbar spine.

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The current pandemic caused by COVID-19 is the biggest challenge for national health systems for a century. While most medical resources are allocated to treat COVID-19 patients, several non-COVID-19 medical emergencies still need to be treated, including vertebral fractures and spinal cord compression. The aim of this paper is to report the early experience and an organizational protocol for emergency spinal surgery currently being used in a large metropolitan area by an integrated team of orthopaedic surgeons and neurosurgeons.

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The direct posterior approach with subperiosteal dissection of the paraspinal muscles from the vertebrae is considered to be the standard approach for the surgical treatment of adolescent idiopathic scoliosis (AIS). We investigated whether or not a minimally-invasive surgery (MIS) technique could offer improved results.

Introduction. Dual energy X-ray absorptiometry (DEXA) is the gold standard for assessing bone mineral density (BMD) and fracture risk in vivo. However, it has limitations in the spine because vertebrae show marked regional variations in BMD that are difficult to detect clinically. This study investigated whether micro-CT can provide improved estimates of BMD that better predict vertebral strength. Methods. Ten cadaveric vertebral bodies (mean age: 83.7 +/− 10.8 yrs) were scanned using lateral-projection DEXA and Micro-CT. Standardised protocols were used to determine BMD of the whole vertebral body and of anterior/posterior and superior/inferior regions. Vertebral body volume was assessed by water displacement after which specimens were compressed to failure to determine their compressive strength. Specimens were then ashed to determine their bone mineral content (BMC). Parameters were compared using ANOVA and linear regression. Results. Measures of volumetric BMD obtained from Micro-CT were significantly higher than those obtained by DEXA (P<0.001), and estimates using the two techniques were not significantly correlated. DEXA measurements were strongly predictive of compressive strength, with areal BMD of the anterior vertebral body being the best predictor (R. 2. = 0.722, P = 0.002). Micro-CT measurements did not predict strength. Vertebral body BMD (derived from ash weight) correlated more highly with volumetric BMD values obtained from DEXA (R = 0.88) than those obtained from micro-CT (R = 0.72). Conclusion. BMD assessed by lateral DEXA predicted strength and BMC of osteoporotic vertebrae more accurately than micro-CT measures. Poor correlation between BMD measurements from DEXA and micro-CT suggests that ‘phantoms’ used in Micro-CT may require fine-tuning in order to better represent osteoporotic vertebrae

Our study aims to evaluate the efficacy of Wallis implant in management of discogenic back pain. We have prospectively studied thirty patients between 2006 and 2007. Average age of patients was 40.8 years. Average follow-up period 20.6 months (9-28). Main inclusion criteria includes failure of conservative management of low back pain due to degenerative disc disease, preservation of 50% of the disc height and positive discographic features. In majority of the patients the implant was put in at the level of L4-L5. Pre-op and post op SF36 and Oswestry Disability Index (ODI) scores were assessed during clinic follow-up and by telephonic interview. Mean SF36 score improved from thirty-seven (8.3 – 54.3) to 51.4. Mean ODI improved from forty-three (20-60) to 26.5(2-60) (p = 0.026). Complications including superficial infection occurred in one patient, deep infection in one patient, erosion of spinous process in one and displacement of the implant in one case. Three (10%) patients had revision surgery due to various reasons. Wallis interspinous dynamic stabilization system could be used as a soft stabilisation device avoiding fusion and short-term results are promising. In selected group of discogenic low back pain patients it is a useful interim procedure. Long-term follow-up of our series is ongoing

We reviewed the outcome of a retrospective case series of eight patients with atlantoaxial instability who had been treated by percutaneous anterior transarticular screw fixation and grafting under image-intensifier guidance between December 2005 and June 2008. The mean follow-up was 19 months (8 to 27). All eight patients had a solid C1–2 fusion. There were no breakages or displacement of screws. All the patients with pre-operative neck pain had immediate relief from their symptoms or considerable improvement. There were no major complications. Our preliminary clinical results suggest that percutaneous anterior transarticulation screw fixation is technically feasible, safe, useful and minimally invasive when using the appropriate instruments allied to intra-operative image intensification, and by selecting the correct puncture point, angle and depth of insertion

The study was conducted to review the outcome in cases of anterior expandable interbody cages inserted through a posterior only approach. Cases selected were the anterior cage insertion and posterior stabilization patients managed by posterior only approach. Study includes the patients of various pathologies requiring 3 column support. Twenty patients were included in study. Pathology in 9 patients was tuberculosis, trauma in 3, tumours in 3, metastasis in 3 and deformities in 2patients. Patients with or without neurological deficit were included. Cases were carefully assessed and patients with single level involvement were included as more then single level involvement required more extensive exposure and possible nerve root sacrifice. Detailed neurological status was recorded. The surgery was performed in prone position and after posterior stabilization by pedicle screws the extracavitatory approach was used to insert the expandable cage. In cases of suspicious pathologies the samples for histopathology and staining were collected. Morbidity, mortality blood loss, surgical time, complications, outcome of surgery were compared with historical controls of front and back surgery. The insertion of cages from posterior approach was feasible in all carefully planned cases. None of the patients had problem related to implant in form of cage displacement. All the patients had satisfactory outcome. Posterior stabilization of spine with expandable cage insertion from posterior approach saves the operating time, spares the additional surgical incision and blood loss without compromising the outcome. In carefully planned surgeries it gives excellent results irrespective of etiology

Background. Fissures in the anulus fibrosus are common in disc degeneration, and are associated with discogenic pain. We hypothesise that anulus fissures are conducive to the ingrowth of blood vessels and nerves. Purpose. To investigate the mechanical and chemical micro-environment of anulus fissures. Methods. Six thoracolumbar spine specimens, comprising three vertebrae and two discs, were obtained from cadavers aged 68-83 yr. Discs were injected with blue dye to reveal the location of complete anulus fissures. Each specimen was then subjected to 1000 N compression, while intradiscal compressive stress was investigated by pulling a miniature pressure transducer through the disc, in planes likely to cross the anulus fissures. Some additional disc fragments were removed at surgery from patients with discogenic back pain, and examined histologically to gauge the concentration of collagen and proteoglycans within radial fissures, using a qualitative method. Results. Stress profiles were obtained perpendicular to major anulus fissures in seven discs. A marked local reduction in vertically-acting compressive stress usually coincided with fissure location (confirmed at dissection), and stress reductions were inversely proportional to average pressure in the nucleus (r. 2. =0.56, p<0.05). Surgical disc samples showed local depletion of proteoglycans around the margins of radial and circumferential fissures, leaving a collagen-rich scaffold of the type known to support nerve and blood vessel growth. Conclusion. Compressive stresses within anulus fissures are reduced most when the disc nucleus is decompressed, because this facilitates internal displacements of disrupted tissue. Anulus fissures provide a micro-environment that is mechanically and chemically conducive to the ingrowth of blood vessels and nerves

Purpose of the study. To compare safety and efficacy of cervical disc replacement (CRD) in single and multilevel DDD. Patients were followed up at 1, 3, 6, 12 and 24 months. Methods. 249 patients were enrolled. 171 patients were treated at 1-level, 41 treated at 2 levels and 2 patients were treated at 3 levels. Implant was also used adjacent to a fusion with a cage in 35 patients. The diagnosis was cervical degenerative disc disease between C3 and C7 with symptomatic DH. Population was 106 male 143 female, average age 46 (25-71). Clinical assessment included VAS scores for arm and neck pain and Neck Disability Index (NDI). Range of motion (ROM) from flexion/extension lateral view were measured. Results. Of all NDI scores recorded, 86,50 % demonstrated at least 15 points improvement at two years follow up from pre-op scores. 85,1% of VAS arm Pain scores demonstrated an improvement by = 2 points from pre-op scores and 50,8% for VAS neck Pain scores. The breakdown by levels and adjacent to an interbody cage shown that 80% of reported NDI scores demonstrated at least a 15 point improvement post operatively for two level disc replacement. 82,4% demonstrated a greater than 2 points improvement in VAS arm pain and 53,3% for VAS neck pain. For patients that received both implant and an interbody cage, 72,7% demonstrated a greater than 2 point improvement in VAS arm pain and 41,7% for VAS neck pain. Three (1,8%) cases of subsidence and 4 cases of implant loosening/displacement due to inappropriate sizing were reported. Available radiographic findings show on average a ROM of 8,2 ° at 2 years and an overall change in cervical lordosis of 5° from pre-op. Conclusion. Clinical outcomes demonstrated a significant improvement for both the total population (n=249) and for the single level total disc replacement population (n=171). Given these outstanding results single and multilevel TDR with this implant can be considered to be safe. No significant difference was observed between single and multilevel TDR groups regarding clinical, functional and radiological results. Follow up for this series need however to be extended for up to 5 years at least. The role of this implant in multilevel cases as well as in cases to a fused level still need further evaluation although these preliminary results are encouraging