Search Results (21)

Background: Posterior spinal fusion is the mainstay of treatment for Cobb angle over 50 degrees with satisfactory long-term results. In the surgical management of scoliosis, surgeons usually focus on the amount of coronal curvature correction because it can determine the surgical outcome. Nevertheless, there are many factors that contribute to patients’ satisfaction after surgery, and achieving shoulder balance is one of the most vital factors of a successful surgery. Our objective is to study the differences in managing idiopathic scoliosis with pedicle screws versus hybrid fixation with regard to shoulder imbalance postoperatively. Methods: Continuous variables were described using mean and standard deviation, whereas categorical variables were described using frequencies. The association between predictor independent variables with the analyzed outcomes were expressed as (beta coefficients) with their associated 95% confidence intervals. The Alpha significance level was considered at 0.050 level. Results: The mean angle of the clavicle measured a significant drop post-surgery compared to their pre-surgical measured mean clavicular angle, p-value < 0.001, and so did the coracoid height difference: p-value < 0.001. Furthermore, the participants had measured a significantly lower mean angle of the clavicle compared to their baseline; p-value = 0.029, regardless of their surgery type. The participants mean measured coracoid height difference score had correlated positively with their mean angle of the clavicle: beta coefficient = 1.654, p-value < 0.001; when the coracoid height difference increased, so did the mean angle of the clavicle. Conclusions: Posterior spinal fusion is effective in correcting coronal curvature and improving radiographic shoulder asymmetry in AIS. Significant improvements were observed in Cobb angle, clavicle angle, and coracoid height difference, with pedicle screw constructs providing superior curve correction. These findings reinforce the value of individualized surgical planning that considers coronal, sagittal, and cosmetic alignment goals. Full article

Background/Objectives: Long-term bisphosphonate (BP) therapy is an effective treatment for osteoporosis but has been associated with rare complications such as atypical femoral fractures (AFFs). Emerging reports suggest that similar insufficiency fractures may also occur in other skeletal sites, including the lumbar pedicles. This study reports two rare cases of isolated bilateral lumbar pedicle stress fractures in patients on prolonged BP therapy. Along with a structured literature review, the objective was to evaluate whether diagnostic criteria derived from those used for AFFs may apply to these atypical vertebral fractures. Methods: Two patients with osteoporosis and on long-term BP therapy diagnosed with isolated lumbar pedicle stress fractures were retrospectively analyzed. A structured literature review identified similar reported cases. All cases were evaluated using the 2010 American Society for Bone and Mineral Research AFF criteria to assess applicability to isolated pedicle stress fractures. Results: Both patients demonstrated bilateral lumbar pedicle fractures without vertebral body involvement. One was treated conservatively; the other underwent robotic-assisted percutaneous pedicle screw fixation with documented fracture healing at six months. The literature review identified eight similar cases of isolated pedicle fractures in patients on prolonged BP therapy. Clinical course and imaging findings demonstrated stress-type features analogous to AFFs. The proposed AFF-based diagnostic criteria for pedicular insufficiency fractures were found to be applicable to all ten patients. Conclusions: Isolated bilateral pedicle stress fractures may represent a spinal analog of AFFs. Based on shared clinical and imaging features, we propose preliminary diagnostic criteria for atypical pedicular insufficiency fractures. Increased awareness and standardized criteria may aid in early diagnosis and reporting, encouraging further studies on this rare spinal entity. Full article

Background/Objectives: Minimally invasive spine surgery (MISS) is complex and requires proficiency with a variety of technological and robotic modalities. Acquiring these skills is a long and involved process, often with a steep learning curve. This paper seeks to characterize the state of MISS training in neurosurgical and orthopedic residency programs, focusing on their effectiveness at minimizing substantial learning curves in the field, as well as highlighting potential areas for future growth. Methods: We conducted a scoping review of the PubMed, Scopus, and Embase databases utilizing the PRISMA extension for scoping reviews. Results: Of the 100 studies initially identified, 16 were included in our final analysis. MISS training types could be broadly grouped into four categories: virtual simulation (including AR and VR), physical models, hybrid didactic and simulation, and mentored training. Training with these modalities led to improvements in resident performance across multiple different MISS techniques, including percutaneous pedicle screw fixation, MIS dural repair, MIS-TLIF, MIS-LLIF, MIS-ULBD, microscopic discectomy/disk herniation repair, percutaneous needle placement, and surgical navigation. Specific improvements included reduced error rate, operation time, and fluoroscopy exposure, as well as increased procedural knowledge, accuracy, and confidence. Conclusions: The incorporation of MISS training modalities in spine surgery residency leads to increases in simulated performance and could serve as a means of overcoming significant learning curves in the field. Full article

Pedicle screw fixation is a common spinal surgery technique, but concerns remain about stability when screws are malpositioned. Traditional in vitro pull-out tests assess anchorage but lack physiological accuracy. This study examined the stability of correctly placed and intentionally malpositioned pedicle screws on forty vertebrae from five cadavers. Optimal screw paths were planned via CT scans and applied using 3D-printed guides. Four malposition types—medial, lateral, superior, and superior-lateral—were created by shifting the original trajectory. A custom setup applied three consecutive cycles of tensile and compressive load from 50 N to 200 N. Screw inclination under load was measured with a 3D optical system. The results showed increasing screw inclination with higher forces, reaching about 1° at 50 N and 2° at 100 N, similar in both load directions. Significant differences in inclination were only found at 100 N tensile load, where malpositioned screws showed a lower inclination. Overall, malpositioning had no major effect on screw loosening. These findings suggest that minor deviations in screw placement do not significantly compromise mechanical stability. Clinically, the main concern with malpositioning lies in the potential for injury to nearby structures rather than reduced screw fixation strength. Full article

Background: Thoracolumbar and lumbar spine injuries account for 30–60% of spinal fractures, especially at the thoracolumbar junction. Conservative treatment is recommended for stable fractures without neurological symptoms, but studies suggest surgical intervention may offer better outcomes. However, there is no consensus on the best stabilization method. Methods: This non-randomized, prospective study was conducted on 114 patients divided into groups based on the surgical technique selected: pedicle stabilization using Schanz screw constructs (Group One, n = 37) stabilization above and below the fractured vertebra using pedicle screws (Group Two, n = 32), and intermediate fixation with a pedicle screw additionally inserted into the fractured vertebra (Group Three, n = 45). Outcomes were assessed using the Cobb angle, anterior and posterior vertebral wall height, and patient quality of life via the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI). X-ray imaging was performed before, during, and after surgery in the control group. Results: This statistical study showed that the location and type of injury significantly influenced the choice of short-segment stabilization method. In the case of measuring the Cobb angle and the high anterior wall, the statistical analysis showed that the best result was observed in the Schanz Group. Patients from this study group had the lowest pain and the highest efficiency. Conclusions: Schanz screw stabilization may offer superior outcomes for thoracolumbar spine injuries, providing better clinical and quality of life results compared to other methods. Full article

(1) Background: Pelvic fractures, and particularly instabilities of the dorsal pelvic ring, are becoming increasingly prevalent, particularly in orthogeriatric patients. Spino-pelvic triangular osteosynthesis is an effective approach to achieve sufficient stabilization in vertically unstable fractures. This study compares two types of osteosynthesis: the conventional one and a novel instrumentation where the iliosacral screw is placed through a fenestrated iliac screw. (2) Methods: Sixteen artificial osteoporotic L5+pelvis models with an unstable sacral fracture have been instrumented with either an iliac screw connected with a rod to a L5 pedicle screw and an iliosacral screw (TF) or a fenestrated ilium screw connected with a rod to a L5 pedicle screw and an iliosacral screw passing through the fenestra of the iliac screw (TFS). Biomechanical testing was performed using cyclic loading until failure. (3) Results: Both configurations yielded comparable results with regard to initial stiffness, implant loosening, and cycles to failure. The TFS exhibited markedly higher values for cycles to failure and markedly lower values for loosening. However, due to the characteristics of the artificial bone model, these findings were not significant. (4) Conclusions: The novel triangular fixation systems demonstrated comparable results to the standard triangular osteosynthesis configuration. Full article

Background: Skeleton involvement is one of the most significant aspects of Gaucher disease (GD). However, the treatment for spinal involvement in GD among patients undergoing enzyme replacement therapy (ERT) is poorly characterized. We present a case of progressive kyphotic spinal deformity in a young child caused by vertebral involvement, which was managed by posterior spinal fusion without anterior spinal release under ERT. Case presentation: This is a retrospective study. A 10-year-old boy presenting with progression kyphosis (thoracic kyphotic angle of 113°) associated with type-IIIb GD had undergone posterior spinal fusion with segmental pedicle screw fixation (from T6-L3) and Ponte osteotomy. The patient went back to school without further brace protection. Proximal junctional kyphosis (PJK) was observed at 4 months postoperatively. Revision surgery was performed to prevent neurological impairment. Additional posterior spinal fusion from T2–T6 and decompressive laminectomy were performed during the revision surgery. A 2-year follow-up showed no recurrence of PJK and solid fusion was achieved in the patient under ERT and brace protection. Conclusions: Posterior spinal fusion without anterior spinal release is a good treatment option for severe spinal deformity in patients with GD. However, the fusion level and reinforced fixation require careful consideration. Revision surgery and brace protection is needed as long as PJK is observed. Full article

(1) Background: The amount of blood loss during oblique lumber interbody fusion (OLIF) surgery is often underestimated and may contribute to adverse postoperative outcomes. This study aims to evaluate hidden blood loss (HBL) in patients who underwent OLIF for degenerative lumbar spine disease and to analyze its risk factors. (2) Methods: The medical records of 179 patients who underwent OLIF surgery from 2015 to 2022 were reviewed. The HBL and total blood loss (TBL) were estimated using the Gross formula. Pearson correlation, Spearman correlation, and multivariate linear regression analyses were used to investigate risk factors for HBL. (3) Results: The mean HBL was 675.2 mL, and the mean hemoglobin loss was 1.7 g/dL during OLIF surgery. In the multivariate linear regression analysis, TBL (p < 0.001), estimated blood loss (p < 0.001), and pedicle screw fixation type (p = 0.039) were identified as independent risk factors of HBL. (4) Conclusions: The OLIF is associated with substantial perioperative HBL, for which we identified risk factors of TBL, EBL, and pedicle screw fixation type. Notably, OLIF with percutaneous pedicle screw fixation resulted in greater HBL than stand-alone OLIF or OLIF with open pedicle screw fixation. Full article

The apical hypokyphosis of scoliotic patients is thought to lead to decreased lung capacity and cause shortness of breath. Additionally, concave rod curve reduction is a problem in the correction of apical hypokyphosis in posterior spinal fusion surgery in adolescent idiopathic scoliosis (AIS). We investigated the contributions of rod rotation (RR) with an outrigger device, followed by differential rod contouring (DRC) with the outrigger attached to the concave rod, designed to prevent concave rod curve-flattening. We analyzed and compared the results of segmental pedicle screw fixation without the outrigger in 41 AIS patients with thoracic curves (Lenke type I, 25; type II, 16) to those corrected using the outrigger in 36 patients (Lenke type I, 24; type II,12). The changes in the Cobb angle, apical kyphosis of five vertebrae, thoracic kyphosis (TK, T4–12), correction rate, correction angle of apical vertebral rotation, spinal penetration index (SPi), and rib hump index (RHi) before and after surgery were measured, and the contribution of the outrigger was analyzed. The mean scoliosis correction rates without and with the outrigger were 72.1° and 75.6°, respectively (p = 0.03). Kyphosis of the five apical vertebrae and TK were significantly greater in the surgery with the outrigger (p = 0.002). Significantly greater improvements in SPi and RHi were also noted in the surgery with the outrigger (p < 0.05). The use of concave RR and convex DRC with the outrigger appear to be advantageous for correcting apical hypokyphosis, followed by the subsequent formation of TK. As a result, breathing problems are less likely to occur during daily life because of improvements in SPi and RHi. Full article

Background and Objectives: C-arm-free MIS techniques can offer significantly reduced rates of postoperative complications such as inadequate decompression, blood loss, and instrumentation misplacement. Another advantageous long-term aspect is the notably diminished exposure to radiation, which is known to cause malignant changes. This study emphasizes that, in some cases of spinal conditions that require a procedural intervention, C-arm-free MIS techniques hold stronger indications than open surgeries guided by image intensifiers. Materials and Methods: This study includes a retrospective analysis and review of various cervical and thoracic spinal procedures, performed in our hospital, applying C-arm-free techniques. The course of this study explains the basic steps of the procedures and demonstrates postoperative and intraoperative results. For anterior cervical surgery, we performed OPLL resection, while for posterior cervical surgery, we performed posterior fossa decompression for Chiari malformation, minimally invasive cervical pedicle screw fixation (MICEPS), and modified Goel technique with C1 lateral mass screw for atlantoaxial subluxation. Regarding the thoracic spine, we performed anterior correction for Lenke type 5 scoliosis and transdiscal screw fixation for diffuse idiopathic skeletal hyperostosis fractures. Results: C-arm-free techniques are safe procedures that provide precise and high-quality postoperative results by offering sufficient spine alignment and adequate decompression depending on the case. Navigation can offer significant assistance in the absence of normal anatomical landmarks, yet the surgeon should always appraise the quality of the information received from the software. Conclusions: Navigated C-arm-free techniques are safe and precise procedures implemented in the treatment of surgically demanding conditions. They can significantly increase accuracy while decreasing operative time. They represent the advancement in the field of spine surgery and are hailed as the future of the same. Full article

Pullout strength is an important indicator of the performance and longevity of pedicle screws and can be heavily influenced by the screw design, the insertion technique and the quality of surrounding bone. The purpose of this study was to investigate the pullout strength of three different pedicle screws inserted using three different strategies and with two different loading conditions. Three pedicle screws with different thread designs (single-lead-thread (SLT) screw, dual-lead-thread (DLT) screw and mixed-single-lead-thread (MSLT) screw) were inserted into a pre-drilled rigid polyurethane foam block using three strategies: (A) screw inserted to a depth of 33.5 mm; (B) screw inserted to a depth of 33.5 mm and then reversed by 3.5 mm to simulate an adjustment of the tulip height of the pedicle screw and (C) screw inserted to a depth of 30 mm. After insertion, each screw type was set up with and without a cyclic load being applied to the screw head prior to the pullout test. To ensure that the normality assumption is met, we applied the Shapiro–Wilk test to all datasets before conducting the non-parametric statistical test (Kruskal–Wallis test combined with pairwise Mann–Whitney-U tests). All screw types inserted using strategy A had a significantly greater pullout strength than those inserted using strategies B and C, regardless of if the screw was pre-loaded with a cyclic load prior to testing. Without the use of the cyclic pre-load, the MSLT screw had a greater pullout strength than the SLT and DLT screws for all three insertion strategies. However, the fixation strength of all screws was reduced when pre-loaded before testing, with the MSLT screw inserted using strategy B producing a significantly lower pullout strength than all other groups (p < 0.05). In contrast, the MSLT screw using insertion strategies A and C had a greater pullout strength than the SLT and DLT screws both with and without pre-loading. In conclusion, the MSLT pedicle screw exhibited the greatest pullout strength of the screws tested under all insertion strategies and loading conditions, except for insertion strategy B with a cyclic pre-load. While all screw types showed a reduced pullout strength when using insertion strategy B (screw-out depth adjustment), the MSLT screw had the largest reduction in pullout strength when using a pre-load before testing. Based on these findings, during the initial screw insertion, it is recommended to not fully insert the screw thread into the bone and to leave a retention length for depth adjustment to avoid the need for screw-out adjustment, as with insertion strategy B. Full article

Lumbar spondylolysis involves anatomical defects of the pars interarticularis, which causes instability during motion. The instability can be addressed through instrumentation with posterolateral fusion (PLF). We developed a novel pedicle screw W-type rod fixation system and evaluated its biomechanical effects in comparison with PLF and Dynesys stabilization for lumbar spondylolysis via finite element (FE) analysis. A validated lumbar spine model was built using ANSYS 14.5 software. Five FE models were established simulating the intact L1–L5 lumbar spine (INT), bilateral pars defect (Bipars), bilateral pars defect with PLF (Bipars_PLF), Dynesys stabilization (Bipars_Dyn), and W-type rod fixation (Bipars_Wtyp). The range of motion (ROM) of the affected segment, the disc stress (DS), and the facet contact force (FCF) of the cranial segment were compared. In the Bipars model, ROM increased in extension and rotation. Compared with the INT model, Bipars_PLF and Bipars_Dyn exhibited remarkably lower ROMs for the affected segment and imposed greater DS and FCF in the cranial segment. Bipars_Wtyp preserved more ROM and generated lower stress at the cranial segment than Bipars_PLF or Bipars_Dyn. The injury model indicates that this novel pedicle screw W-type rod for spondylolysis fixation could return ROM, DS, and FCF to levels similar to preinjury. Full article

Background: Thoracolumbar burst fractures are a common traumatic vertebral fracture in the spine, and pedicle screw fixation has been widely performed as a safe and effective procedure. However, after the stabilization of the thoracolumbar burst fractures, whether or not to remove the pedicle screw implant remains controversial. This review aimed to assess the benefits and risks of pedicle screw instrument removal after fixation of thoracolumbar burst fractures. Methods: Data sources, including PubMed, EMBASE, Cochrane Library, Web of Science, Google Scholar, and Clinical trials.gov, were comprehensively searched. All types of human studies that reported the benefits and risks of implant removal after thoracolumbar burst fractures, were selected for inclusion. Clinical outcomes after implant removal were collected for further evaluation. Results: A total of 4051 papers were retrieved, of which 35 studies were eligible for inclusion in the review, including four case reports, four case series, and 27 observational studies. The possible risks of pedicle screw removal after fixation of thoracolumbar burst fractures include the progression of the kyphotic deformity and surgical complications (e.g., surgical site infection, neurovascular injury, worsening pain, revision surgery), while the potential benefits of pedicle screw removal mainly include improved segmental range of motion and alleviated pain and disability. Therefore, the potential benefits and possible risks should be weighed to support patient-specific clinical decision-making about the removal of pedicle screws after the successful fusion of thoracolumbar burst fractures. Conclusions: There was conflicting evidence regarding the benefits and harms of implant removal after successful fixation of thoracolumbar burst fractures, and the current literature does not support the general recommendation for removal of the pedicle screw instruments, which may expose the patients to unnecessary complications and costs. Both surgeons and patients should be aware of the indications and have appropriate expectations of the benefits and risks of implant removal. The decision to remove the implant or not should be made individually and cautiously by the surgeon in consultation with the patient. Further studies are warranted to clarify this issue. Level of evidence: level 1. Full article

To investigate the feasibility of using absorbable Mg alloy pedicle screws for atlantoaxial dislocation fixation, four types of Mg alloy pedicle screws of different thread forms were designed, and simulation analysis of the pull-out force was performed using the finite element method. Stress and displacement distributions of the atlantoaxial fixation model were obtained. Subsequently, screw samples were prepared using the WE43 Mg alloy for extraction, torsion, and immersion corrosion tests. Finite element analysis results showed that the pull-out forces of triangular, rectangular, trapezoidal, and zigzag thread screws were 552.61, 540.91, 546.4, and 542.74 N, respectively, and the stresses on the screws were 146, 185, 195, and 265 MPa, respectively, when they were pulled out. In other words, the triangular thread screw had the largest pull-out resistance and smallest stress peak. The average corrosion rate of Mg alloy screws in vitro was 0.46 mg·cm⁻²·day⁻¹. Compared with that before corrosion, the extraction resistance of the corroded screws did not change significantly; however, the torsional strength decreased, but it was still greater than the torque required for screw implantation. It can be concluded that triangular thread Mg alloy pedicle screws have good extraction resistance and mechanical stability and can meet the load-bearing requirements for atlantoaxial dislocation fixation. The degradation of the Mg alloy reduced the mechanical strength of the screws, but the triangularly threaded screws can still maintain their effectiveness. Full article

We aim to delineate whether there is increased blood loss with the use of cannulated pedicle screws compared to solid pedicle screws in patients undergoing posterior spinal fusion. A single-centre retrospective case-control study was undertaken on patients undergoing PSF for spinal fractures. Cannulated screw fixation was compared with solid screw fixation. Intraoperative blood loss was estimated using pre and postoperative haemoglobin levels, recorded estimated blood loss and cell saver reports. Anticoagulation, blood product administration, operative time and number of levels fused were assessed. A total of 64 cases, 32 in each cohort, were included in the analysis. Overall mean haemoglobin reduction from pre- to post-operative was 2.82 ± 1.85 g/L per screw inserted in the cannulated group, compared to a haemoglobin decrease of 2.81 ± 1.521 g/L per screw inserted in the solid screw group (p = 0.971). Total estimated intraoperative blood loss was 616.3 + 355.4 mL in the cannulated group, compared to 713.6 + 473.5 mL in the solid screw group (p = 0.456). Patients with preoperative thrombocytopenia had a transfusion rate of 0.5 ± 0.71 units/patient compared to 0.04 ± 0.19 units/patient in patients with normal platelet levels (p < 0.005). The differences in blood loss observed between cannulated and solid pedicle screws are non-significant overall. The largest predictor for need of transfusion was pre-operative thrombocytopenia, regardless of the type of screw used. Full article