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PURPOSE: To evaluate proximal junctional biomechanics of a MLSS relative to traditional pedicle screw fixation at the proximal extent of T10-pelvis posterior instrumentation constructs (T10-p PSF). METHODS: A previously validated three-dimensional osseoligamentous spinopelvic finite element (FE) model was used to compare proximal junctional range-of-motion (ROM), vertebral body stresses, and discal biomechanics between two groups: (1) T10-p with a T10-11 MLSS (T10-11 MLSS) and (2) T10-p with a traditional T10 pedicle screw (Traditional T10-PS). RESULTS: The T10-11 MLSS had a 5% decrease in T9 cortical bone stress compared to Traditional T10-PS. Conversely, the T10 and T11 bone stresses increased by 46% and 98%, respectively, with T10-11 MLSS compared to Traditional T10-PS. Annular stresses and intradiscal pressures (IDP) were similar at T9-T10 between constructs. At the T10-11 disc, T10-11 MLSS decreased annular stresses by 29% and IDP by 48% compared to Traditional T10-PS. Adjacent ROM (T8-9 & T9-10) were similar between T10-11 MLSS and Traditional T10-PS. T10-11 MLSS had 39% greater ROM at T10-11 and 23% less ROM at T11-12 compared to Traditional T10-PS. CONCLUSIONS: In this FE analysis, a T10-11 MLSS at the proximal extent of T10-pelvis posterior instrumentation resulted in increased T10 and T11 cortical bone stresses, decreased discal annular stress and IDP and increased ROM at T10-11, and no change in ROM at the adjacent level. Given the complex and multifactorial nature of proximal junctional kyphosis, these results require additional biomechanical and clinical evaluations to determine the clinical utility of MLSS on the proximal junctions of thoracolumbar posterior instrumented fusions.

Retrospective review of all spinal fusions > 3 levels involving the thoracolumbar and/or sacroiliac at a single institution, by a single surgeon between 3/12/2020 and 8/13/2021 were reviewed. All screws that were secondarily navigated after identified as misdirected on intraoperative CT scan were included. Neuromonitoring reports were culled for mA threshold to triggered EMG response for all redirected screws. Intraoperative, post-de novo screw placement images (fluoroscopy scout and intraoperative CT) and post-redirection intraoperative scoliosis films and post-operative scoliosis films were independently reviewed by a senior neuroradiologist. Fifty redirected screws in the thoracic, lumbar, sacral, and ilium were identified as misdirected and redirected via navigation. The new trajectory of all screws was confirmed satisfactory by independent review between a senior neuroradiologist and neurosurgeon. Four screws could not be verified by post-operative imaging (4/50, 8%). All triggered EMG stimulated > 15 mA. No screws required return to the operating room for revision. No patients experienced a post-operative deficit. Redirection of misdirected thoracolumbar and sacroiliac screws can be performed using intraoperative CT and navigation as a means to detect and directly visualize appropriate placement.

Introduction Challenges of treating the injuries of pubic symphysis in patients with combined pelvic injury require developing new techniques for stable minimally invasive osteosynthesis in the acute period of trauma. Purpose of the work was to assess the application of low invasive fixation of the pubic symphysis with a system of transpedicular screws in the patients with combined unstable pelvic injuries in the acute period of the traumatic disease. Materials and methods The results of treatment of 12 patients with polytrauma with unstable pelvic injury with rupture of the pubic symphysis who were treated at Dzhanelidze Research Institute of Emergency Medicine, St. Petersburg, in the period from 2017 to 2023, were analyzed. All the patients underwent final minimally invasive fixation of the pubic symphysis with a system of transpedicular screws in the early period of the traumatic disease. Results The overall assessment of the results in 12 patients found no complications or technical errors during the installation of transpedicular screws. Control CT scans of the pelvis showed that osteosynthesis was stable in all patients, and the position of metal was correct in all. One patient from the study group died in the clinic from massive pulmonary embolism. The long-term results in 11 patients in the period from 6 months to 3 years after trauma were evaluated as excellent and good anatomical and functional results in 10 patients, one case had fair outcome. Discussion The use of bone plates to fix ruptures of the symphysis pubis leads to disruption of its physiological mobility, and the patient’s activity in the postoperative period can cause an implant fracture. Original dynamic plates and wire cerclage help avoid this complication; however, all these techniques involve significant surgical trauma and blood loss, as well as the risk of postoperative wound suppuration. Minimally invasive methods of fixation using cannulated screws, systems such as Endobutton, Tight Rope can reduce intraoperative trauma and the risk of complications (blood loss, suppuration); however, the procedure for their installation is quite complex and lengthy, and for greater stability, external fixation of the pelvic ring is often required. The proposed minimally invasive fixation of the pubic symphysis with a system of transpedicular screws avoids a lot of shortcomings and is sufficiently stable. Conclusion The method of minimally invasive fixation of the pubic symphysis with a system of transpedicular screws meets current requirements in the treatment of patients with polytrauma and unstable pelvic injury, and it may be successfully used in the acute period of trauma.

Abstract Background Minimally invasive posterior fixation surgery for pyogenic spondylitis is known to reduce invasiveness and complication rates; however, the outcomes of concomitant insertion of pedicle screws (PS) into the infected vertebrae via the posterior approach are undetermined. This study aimed to assess the safety and efficacy of PS insertion into infected vertebrae in minimally invasive posterior fixation for thoracolumbar pyogenic spondylitis. Methods This multicenter retrospective cohort study included 70 patients undergoing minimally invasive posterior fixation for thoracolumbar pyogenic spondylitis across nine institutions. Patients were categorized into insertion and skip groups based on PS insertion into infected vertebrae, and surgical data and postoperative outcomes, particularly unplanned reoperations due to complications, were compared. Results The mean age of the 70 patients was 72.8 years. The insertion group (n = 36) had shorter operative times (146 versus 195 min, p = 0.032) and a reduced range of fixation (5.4 versus 6.9 vertebrae, p = 0.0009) compared to the skip group (n = 34). Unplanned reoperations occurred in 24% (n = 17) due to surgical site infections (SSI) or implant failure; the incidence was comparable between the groups. Poor infection control necessitating additional anterior surgery was reported in four patients in the skip group. Conclusions PS insertion into infected vertebrae during minimally invasive posterior fixation reduces the operative time and range of fixation without increasing the occurrence of unplanned reoperations due to SSI or implant failure. Judicious PS insertion in patients with minimal bone destruction in thoracolumbar pyogenic spondylitis can minimize surgical invasiveness.

Introduction: Transpedicular screw placement has superior pullout strength compared to alternative forms of spinal fusion and is often performed in deformity correction surgery with navigation for optimal accuracy and reliability. Freehand technique for pedicle screws minimizes operation time and radiation exposure without fluoroscopy but is not widely adopted given the challenge of difficult anatomical corridors and accurate placement, especially in idiopathic scoliosis and advanced deformity. We used a computer-generated model to assess a proof-of-concept and anatomical feasibility of a freehand screw technique in severe scoliosis. Methods: Three-dimensional (3D) reconstructions of vertebra from a sample of two male patients with severe idiopathic scoliosis deformity (1 thoracic and 1 lumbar) with Cobb angles of 100° were used for planned placement of 17 levels of thoracolumbar (6.5 mm × 45 mm) pedicle screws. 3D reconstruction of each vertebra was created and measurements of screw entries and trajectories were reproduced with a 3D slicer software image computing platform. Results: Accurate transpedicular screw placement is possible with anatomical landmarks based on the 3D reconstructed vertebral levels. A series of 5 figures were assembled to demonstrate sagittal, coronal, and axial planes and key anatomical landmarks and trajectories of thoracic and lumbar freehand pedicle screws in severe idiopathic scoliosis. Conclusions: Anatomical landmarks for freehand transpedicular screw placement (between pedicle, lamina, and superior articulating process) are constant and reliable in severe idiopathic scoliosis as evidenced by 3D computer modeling. Preoperative computed tomography modeling may assist appropriate screw entry and trajectory based on anatomical landmarks for spine surgeons, and guide freehand technique for screw placement in adolescent idiopathic scoliosis.

Background: Minimally invasive posterior fixation surgery for pyogenic spondylitis is known to reduce invasiveness and complication rates; however, the outcomes of concomitant insertion of pedicle screws (PS) into the infected vertebrae via the posterior approach are undetermined. This study aimed to assess the safety and efficacy of PS insertion into infected vertebrae in minimally invasive posterior fixation for thoracolumbar pyogenic spondylitis. Methods: This multicenter retrospective cohort study included 70 patients undergoing minimally invasive posterior fixation for thoracolumbar pyogenic spondylitis across nine institutions. Patients were categorized into insertion and skip groups based on PS insertion into infected vertebrae, and surgical data and postoperative outcomes, particularly unplanned reoperations due to complications, were compared. Results: The mean age of the 70 patients was 72.8 years. The insertion group (n = 36) had shorter operative times (146 versus 195 min, p = 0.032) and a reduced range of fixation (5.4 versus 6.9 vertebrae, p = 0.0009) compared to the skip group (n = 34). Unplanned reoperations occurred in 24% (n = 17) due to surgical site infections (SSI) or implant failure; the incidence was comparable between the groups. Poor infection control necessitating additional anterior surgery was reported in four patients in the skip group. Conclusions: PS insertion into infected vertebrae during minimally invasive posterior fixation reduces the operative time and range of fixation without increasing the occurrence of unplanned reoperations due to SSI or implant failure. Judicious PS insertion in patients with minimal bone destruction in thoracolumbar pyogenic spondylitis can minimize surgical invasiveness. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective review of a prospective randomized trial. Objectives: To compare outcome scores and fusion rates in patients with and without pedicle screw-associated facet joint violation (FJV) after a single-level lumbar fusion. Methods: Clinical outcomes data and computed tomography (CT) imaging were reviewed for 157 patients participating in a multicenter prospective trial. Post-operative CT scans at 12-months follow-up were examined for fusion status and FJV. Patient-reported outcomes (PROs) included Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for leg and low back pain. Chi-square test of independence was used to compare proportions between groups on categorical measures. Two-sample t-test was used to identify differences in mean patient outcome scores. Logistic regression models were performed to determine association between FJV and fusion rates. Results: Of the 157 patients included, there were 18 (11.5%) with FJV (Group A) and 139 (88.5%) without FJV (Group B). Patients with FJV experienced less improvement in ODI (P =.004) and VAS back pain scores (P =.04) vs patients without FJV. There was no difference in mean VAS leg pain (P =.4997). The rate of fusion at 12-months for patients with FJV (27.8%) was lower compared to those without FJV (71.2%) (P =.0002). Patients with FJV were 76% less likely to have a successful fusion at 12-months. Conclusion: Pedicle screw-associated violation of the adjacent unfused facet joint during single-level lumbar fusion is associated with less improvement in back pain, back pain-associated disability, and a lower fusion rate at 1-year after surgery. [ABSTRACT FROM AUTHOR]

This study aimed to quantify the change in pressure on the cage during compression manipulation in lumbar interbody fusion. While the procedure involves applying compression between pedicle screws to press the cage against the endplate, the exact compression force remains elusive. We hypothesize that an intact facet joint might serve as a fulcrum, potentially reducing cage pressure. Pressure on the intervertebral disc cage was measured during compression manipulation in 4 donor cadavers undergoing lumbar interbody fusion. Unilateral facetectomy models with both normal and parallel compression and bilateral facetectomy models were included. A transforaminal lumbar interbody fusion cage with a built-in load cell measured the compression force. Pressure data from 14 discs indicated a consistent precompression pressure average of 68.16 N. Following compression, pressures increased to 125.99 N and 140.84 N for normal and parallel compression postunilateral facetectomy, respectively, and to 154.58 N and 150.46 N for bilateral models. A strong linear correlation (correlation coefficient: 0.967, P < 0.0001) between precompression and postcompression pressures emphasized the necessity of sufficient precompression pressure for achieving desired postcompression outcomes. None of the data showed a decrease in compression force to the cage with the compression maneuver. Both normal and parallel compression maneuvers effectively increased the pressure on the cage, irrespective of the facet joint resection status. Compression manipulation consistently enhanced compressive force on the cage. However, when baseline pressure is low, the manipulation might not yield significant increases in compression force. This underlines the essential role of meticulous precompression preparation in enhancing surgical outcomes. [ABSTRACT FROM AUTHOR]

Background: Modern surgical techniques allow for the correction of spinal deformity, stopping its progression and improving pain relief and social and physical functioning. These instruments have different implant designs, screws, and rod diameters and can be composed of different metal alloys with different hardnesses, which can have a significant impact on the effect of correcting spinal deformities. We designed a retrospective cohort study based on the same surgical technique and spine system using different implant sizes, and compared the results across them. Methods: This is a retrospective review of adolescent idiopathic scoliosis (AIS) patients who underwent posterior spinal fusion (PSF) between 2016 and 2022 with a minimum two-year follow-up (FU) using two spinal implant systems: 5.5 and 6.0 mm diameter screws with double 5.5 mm titanium rods (Group 1 (G1)), and 6.0 and 6.5 mm diameter pedicle screws with double 6.0 mm cobalt–chromium rods (Group 2 (G2)). The evaluated data were as follows: preoperative personal data, radiographic outcomes, complications, and health-related quality of life questionnaire (HRQoL). The parameters were reviewed preoperatively, after the final fusion, and during the FU. Results: The mean age of all 260 patients at surgery was 14.8 years. The average BMI was also similar in both groups and was noted as 21. The mean levels of fusion and screw density were similar in both groups. The mean preoperative major curves (MCs) were 57.6° and 62.5° in G1 and G2, respectively. The mean flexibility of the curves was noted as 35% in G1 and 33% in G2. After definitive surgery, the mean percentage correction of the MC was better in G2 vs. G1, with 74.5% vs. 69.8%, respectively (p < 0.001). At the final FU, the average loss of correction was 5.9° for G1 and 3.2° for G2 (p < 0.001). The mean preoperative (TK) thoracic kyphosis (T2–T5) was 12.2° in G1 and 10.8° in G2. It was corrected to 15.2° in G1 and to 13° in G2. At the FFU, we noted a significant difference in the TK (T2–T5) between the groups, with 16.7° vs. 9.6° for G1 vs. G2, respectively (p < 0.001). Statistical significance was observed between the preoperative sagittal balance and the final follow-up for both groups (p < 0.001). Conclusions: AIS patients surgically treated with screws with a larger diameter and thicker and stiffer rods showed greater correction and postoperative thoracic kyphosis without implant failure. The complication rates, implant density, and clinical outcomes remained similar. The radiographic benefits reported in this cohort study suggest that large-sized screws and stiffer rods for the correction of pediatric spinal deformities are safe and very effective. [ABSTRACT FROM AUTHOR]

Objective: To compare the image quality of low-dose CT (LD-CT) with tin filtration of the lumbar spine after metal implants to standard clinical CT, and to evaluate the potential for metal artifact and dose reduction. Materials and methods: CT protocols were optimized in a cadaver torso. Seventy-four prospectively included patients with metallic lumbar implants were scanned with both standard CT (120 kV) and tin-filtered LD-CT (Sn140kV). CT dose parameters and qualitative measures (1 = worst,4 = best) were compared. Quantitative measures included noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and the width and attenuation of the most prominent hypodense metal artifact. Standard CT and LD-CT were assessed for imaging findings. Results: Tin-filtered LD-CT was performed with 60% dose saving compared to standard CT (median effective dose 3.22 mSv (quartile 1–3: 2.73–3.49 mSv) versus 8.02 mSv (6.42–9.27 mSv; p <.001). Image quality of CT and tin-filtered low-dose CT was good with excellent depiction of anatomy, while image noise was lower for CT and artifacts were weaker for tin-filtered LD-CT. Quantitative measures also revealed increased noise for tin-filtered low-dose CT (41.5HU), lower SNR (2) and CNR (0.6) compared to CT (32HU,3.55,1.03, respectively) (all p <.001). However, tin-filtered LD-CT performed superior regarding the width and attenuation of hypodense metal artifacts (2.9 mm and -767.5HU for LD-CT vs. 4.1 mm and -937HU for CT; all p <.001). No difference between methods was observed in detection of imaging findings. Conclusion: Tin-filtered LD-CT with 60% dose saving performs comparable to standard CT in detection of pathology and surgery related complications after lumbar spinal instrumentation, and shows superior metal artifact reduction. [ABSTRACT FROM AUTHOR]

Pedicle screws are commonly used for posterior fixation of the lumbar spine. Inaccuracy of screw placement can lead to disastrous complications. As fluoroscopic assisted pedicle screw instrumentation is the most frequently used technique, the aim of this study was to assess the specificity, sensitivity and accuracy of intraoperative fluoroscopy to detect mediolateral screw malpositioning. We also analyzed whether the addition of an oblique view could improve these parameters. On 12 human cadavers, 138 pedicle screws were placed intentionally either with 0 to 2 mm (75 screws), with 2 to 4 mm (six medial and 12 lateral screws) and with >4 mm (22 medial and 23 lateral screws) breach of the pedicle from Th12 to L5. Three experienced spine surgeons evaluated the screw positioning in fluoroscopic AP views and 4 weeks later in AP views and additional oblique views. The surgeons' interpretation was compared with the effective screw position on postoperative CT scans. Pedicle breaches greater than 2 mm were detected in 68% with AP views and in 67% with additional oblique views (p=.742). The specificity of AP views was 0.86 and 0.93 with additional oblique views (p=<.01). The accuracy was 0.78 with AP views and 0.81 with AP + oblique views (p=.114). There was a substantial inter-reader agreement (Fleiss's kappa: 0.632). Fluoroscopic screening of pedicle screw misplacement has a limited sensitivity. Adding an oblique view improves specificity but not sensitivity and accuracy in detecting screw malpositions. When in doubt of a screw malpositioning, other modalities than a fluoroscopic assisted pedicle screw instrumentation such as intraoperative CT imaging or an intraoperative exploration of the screw trajectory must be evaluated. [ABSTRACT FROM AUTHOR]

Introduction: Transpedicular screw placement has superior pullout strength compared to alternative forms of spinal fusion and is often performed in deformity correction surgery with navigation for optimal accuracy and reliability. Freehand technique for pedicle screws minimizes operation time and radiation exposure without fluoroscopy but is not widely adopted given the challenge of difficult anatomical corridors and accurate placement, especially in idiopathic scoliosis and advanced deformity. We used a computer-generated model to assess a proof-of-concept and anatomical feasibility of a freehand screw technique in severe scoliosis. Methods: Three-dimensional (3D) reconstructions of vertebra from a sample of two male patients with severe idiopathic scoliosis deformity (1 thoracic and 1 lumbar) with Cobb angles of 100° were used for planned placement of 17 levels of thoracolumbar (6.5 mm × 45 mm) pedicle screws. 3D reconstruction of each vertebra was created and measurements of screw entries and trajectories were reproduced with a 3D slicer software image computing platform. Results: Accurate transpedicular screw placement is possible with anatomical landmarks based on the 3D reconstructed vertebral levels. A series of 5 figures were assembled to demonstrate sagittal, coronal, and axial planes and key anatomical landmarks and trajectories of thoracic and lumbar freehand pedicle screws in severe idiopathic scoliosis. Conclusions: Anatomical landmarks for freehand transpedicular screw placement (between pedicle, lamina, and superior articulating process) are constant and reliable in severe idiopathic scoliosis as evidenced by 3D computer modeling. Preoperative computed tomography modeling may assist appropriate screw entry and trajectory based on anatomical landmarks for spine surgeons, and guide freehand technique for screw placement in adolescent idiopathic scoliosis. [ABSTRACT FROM AUTHOR]

BackgroundCervical spinal fusion surgeries require accurate placement of the pedicle screws. Any misplacement/misalignment of these screws may lead to injuries to the spinal cord, arteries and other organs. Template guides have emerged as accurate and cost-effective tools for the safe and rapid insertions of pedicle screws.Questions/PurposesNovel patient-specific single- and multi-level non-covering templates for cervical pedicle screw insertions were designed, 3D-printed, and evaluated.MethodsCT scans of two patients were acquired to reconstruct their 3D spine model. Two sets of single-level (C3-C7) and multi-level (C4-C6) templates were designed and 3D-printed. Pedicle screws were inserted into the 3D-printed vertebrae by free-hand and guided techniques. For single-level templates, a total of 40 screws (2 patients × 5 vertebrae × 2 methods × 2 screws) and for multi-level templates 24 screws (2 patients × 3 vertebrae × 2 methods × 2 screws) were inserted by an experienced surgeon. Postoperative CT images were acquired to measure the errors of the entry point, 3D angle, as well as axial and sagittal plane angles of the inserted screws as compared to the initial pre-surgery designs. Accuracy of free-hand and guided screw insertions, as well as those of the single- and multi-level guides, were also compared using paired t-tests.ResultsDespite the minimal removal of soft tissues, the 3D-printed templates had acceptable stability on the vertebrae during drillings and their utilization led to statistically significant reductions in all error variables. The mean error of entry point decreased from 3.02 mm (free-hand) to 0.29 mm (guided) using the single-level templates and from 5.7 mm to 0.76 mm using the multi-level templates. The percentage reduction in mean of other error variables for, respectively, single- and multi-level templates were as follows: axial plane angle: 72% and 87%, sagittal plane angle: 56% and 78%, and 3D angle: 67% and 83%. The error variables for the multi-level templates generally exceeded those of the single-level templates. The use of single- and multi-level templates also considerably reduced the duration of pedicle screw placements.ConclusionThe novel single- and multi-level non-covering templates are valuable tools for the accurate placement of cervical pedicle screws.

Introduction: To compare post-operative outcomes of percutaneous pedicle screw fixation (PPSF) vs open pedicle screw fixation (OPSF) in patients with thoracolumbar spine fractures with no neurological deficits. Materials and methods: In a randomised controlled trial, patients received short-segment fixation with intermediate screws. We assessed post-operative back pain (Visual Analog Scale or VAS), blood loss, operative/fluoroscopy times, radiographic parameters, and oswestry disability index (ODI) scores at 1, 2, 3, 6, 9, and 12 months. Results: Between January 2018 and October 2019, 31 patients received PPSF and 30 OPSF. Mean intra-operative blood loss was 66.45 (±44.29) ml for PPSF vs 184.83 (±128.36) ml for OPSF (p

Objective This study aimed to assess the degree of interest in robot-assisted spine surgery (RASS) among residents and to investigate the learning curve for beginners performing robotic surgery. Methods We conducted a survey to assess awareness and interest in RASS among young neurosurgery residents. Subsequently, we offered a hands-on training program using a dummy to educate one resident. After completing the program, the trained resident performed spinal fusion surgery with robotic assistance under the supervision of a mentor. The clinical outcomes and learning curve associated with robotic surgery were then analyzed. Results Neurosurgical residents had limited opportunities to participate in spinal surgery during their training. Despite this, there was a significant interest in the emerging field of robotic surgery. A trained resident performed RASS under the supervision of a senior surgeon. A total of 166 screw insertions were attempted in 28 patients, with 2 screws failing due to skiving. According to the Gertzbein-Robbins classification, 85.54% of the screws were rated as grade A, 11.58% as grade B, 0.6% as grade C, and 1.2% as grade D. The clinical acceptance rate was approximately 96.99%, which is comparable to the results reported by senior experts and time per screw statistically significantly decreased as experience was gained. Conclusion RASS can be performed with high accuracy within a relatively short timeframe, if residents receive adequate training.

Lumbar disc herniation with dorsal epidural migration is a rare clinical condition that can present with severe neurological deficit and cauda equina syndrome. Diagnosis poses a challenge as it mimics other dorsal epidural pathologies like tumors, cysts, and abscesses. Timely diagnosis and early surgical intervention with wide decompression can improve the neurological outcome. Minimally invasive technique has the advantage of minimal muscle damage, early rehabilitation, and equal clinical outcomes to those of standard laminectomy. In this report, we describe a case of a 63-year-old male with lumbar disc herniation at L3-L4 level with foraminal extension and dorsal epidural migration with neurological deficit managed by minimally invasive microtubular decompression and spinal stabilization.

Study Design: Prospective observational cohort. Objectives: To examine the cost-effectiveness of IntraOperative ElectroMyeloGraphy (IO-EMG) by evaluating how often an abnormal IO-EMG signal changed the surgeon's surgical plan, or replaced a pedicle screw either intra-operatively or as a second unplanned surgery. Methods: Patients undergoing instrumented posterolateral lumbar fusion were monitored with intraoperative triggered EMG's. Pedicle screws were placed freehand from L1 to S1 by attending physicians and fellows. Concern for pedicle breach was a screw stimulation<10 mA. Results: There were 145 cases with a total of 725 pedicle screws placed. Mean age was 57.8 ± 14.2 yrs, OR time was 238 ± 95 minutes, EBL was 426.8 ± 354.3cc. Mean number of surgical levels fused was 2.7 ± 1.1. 686 (95%) screws stimulated at >10 mA and 39 (5%) screws stimulated at <10 mA. All 39 screws were removed and pedicles re-examined. Intraoperative screw repositioning was necessary in 8 of 145 cases (6%). No patient required a return to the OR for screw repositioning. As a worst case cost analysis, assuming the 8 patients requiring intraoperative screw positioning would have returned to the OR at a cost of $11,798 per readmission, the per patient cost is $651 which is less than the ION per patient cost of $750. Conclusions: Only 1% of the 725 lumbar pedicle screws placed in 8 of 145 cases required repositioning. Due to the infrequency of pedicle wall breaches and the cost of ION, the utility of this modality in straightforward lumbar fusions should be critically evaluated. [ABSTRACT FROM AUTHOR]

Pedicle screws is the current gold standard in spine surgery, achieving a solid tricolumnar fixation which is unreachable by wires and hooks. The freehand technique is the most widely adopted for pedicle screws placing. While freehand technique has been classically performed with manual tools, there has been a recent trend toward the use of power tools. However, placing a pedicle screw remains a technically demanding procedure with significant risk of complications. The aim of this article is to retrospectively evaluate safety and accuracy of free-hand power-assisted pedicle screw placement in a cohort of patients who underwent correction and fusion surgery for scoliosis (both idiopathic and non-idiopathic) in our department. A retrospective review of all patients with scoliosis who underwent surgery and received a postoperative CT scan in our department in a 9-year period was undertaken. Screw density, number and location of pedicle screws were measured using pre and postoperative full-length standing and lateral supine side-bending radiographs. Then, postoperative CT scan was used to assess the accuracy of screw placement according to Gertzbein-Robbins scale. Malpositioned screws were divided according to their displacement direction. Finally, intra and postoperative neurological complications and the need for revision of misplaced screws were recorded. A total of 205 patients were included, with a follow-up of 64.9 ± 38.67 months. All constructs were high density (average density 1.97 ± 0.04), and the average number of fusion levels was 13.72 ± 1.97. A total of 5522 screws were placed: 5308 (96.12%) were grade A, 141 (2.5%) grade B, 73 (1.32%) grade C. Neither grade D nor grade E trajectories were found. The absolute accuracy (grade A) rate was 96.12% (5308/5522) and the effective accuracy (within the safe zone, grade A + B) was 98.6% (5449/5522). Of the 73 misplaced screws (grade C), 59 were lateral (80.80%), 8 anterior (10.95%) and 6 medial (8.22%); 58 were in convexity, while 15 were in concavity (the difference was not statistically significant, p = 0.33). Intraoperatively, neither neurological nor vascular complications were recorded. Postoperatively, 4 screws needed revision (0.072% of the total): Power-assisted pedicle screw placing may be a safe an accurate technique in the scoliosis surgery, both of idiopathic and non-idiopathic etiology. Further, and higher quality, research is necessary in order to better assess the results of this relatively emerging technique. [ABSTRACT FROM AUTHOR]

Purpose: We aim to compare radiation exposure and implant-related complications of the freehand (FH) technique versus intraoperative image-guided navigation (IN) for pedicle screw placement in adolescent idiopathic scoliosis (AIS) and estimate associated lifetime attributable cancer risks. Methods: A retrospective analysis of prospectively collected data from 40 consecutive AIS patients treated with pedicle screw instrumentation using the FH technique was performed. The dose area product (DAP) and effective dose (ED) were calculated. Screw-related complications were analysed, and the age- and gender-specific lifetime attributable cancer risks were estimated. The results were compared to previously published data on IN used during surgery for AIS. Results: There were no implant-related complications in our cohort. Implant density was 86.6%. The mean Cobb angle of the main curve was 75.2° (SD ± 17.7) preoperatively and 27.7° (SD ± 10.8) postoperatively. The mean ED of our cohort and published data for the FH technique was significantly lower compared to published data on the IN technique (p < 0.001). The risk for radiogenic cancer for our FH technique AIS cohort was 0.0014% for male patients and 0.0029% for female patients. Corresponding risks for IN were significantly higher (p < 0.001), ranging from 0.0071 to 0.124% and from 0.0144 to 0.253% for male and female patients, respectively. Conclusion: The routine use of intraoperative navigation in AIS surgery does not necessarily reduce implant-related complications but may increase radiation exposure to the patient. [ABSTRACT FROM AUTHOR]

BACKGROUND: We compared the raw Ti–Al–V super alloy transpedicular implant screws with boronized and surface-hardened transpedicular implant screws. OBJECTIVE: To improve patients' postoperative prognosis with the production of harder and less fragile screws. METHODS: Surface hardening was achieved by applying green-body encapsulation of the specimen with elemental boron paste which is sintered at elevated temperatures to ensure the boron-metal diffusion. Boron transported into the Ti–Al–V super alloy matrix gradually while suppressing aluminum and a homogeneously boronized surface with a thickness of ∼15 microns was obtained. The uniform external shell was enriched with TiB2, which is one of the hardest ceramics. The Ti-Al-V core material, where boron penetration diminishes, shows cohesive transition and ensures intact core-surface structure. RESULTS: Scanning electron microscope images confirmed a complete homogeneous, uniform and non-laminating surface formation. Energy-dispersive X-ray monitored the elemental structural mapping and proved the replacement of the aluminum sites on the surface with boron ending up the TiB2. The procedure was 8.6 fold improved the hardness and the mechanical resistance of the tools. CONCLUSIONS: Surface-hardened, boronized pedicular screws can positively affect the prognosis. In vivo studies are needed to prove the safety of use. [ABSTRACT FROM AUTHOR]

Study Design: Pedicle screw study. Objective: The selection of pedicle screw parameters usually involves the surgeon's analysis of preoperative CT imaging along with anatomical landmarks and tactile examination. However, there is minimal consensus on a standardized guideline for selection methods on pedicle screws. We aimed to determine the effects of thoracic screw diameter to pedicle width on pullout strength determined by cortical bone purchase. Methods: Biomechanical study performed with human cadaveric thoracic vertebrae and experimentally validated three-dimensional finite element model instrumented with pedicle screws of various diameters. We used a variable (SD/PW) ratio to express the screw selection. We hypothesized a positive correlation between the pullout load determined by the bone purchase and the SD/PW. This relationship was first investigated in a validated finite element model considering bone purchase related to the strength of an upper thoracic vertebra. Then, the correlation to the entire spine is evaluated. Results: The failure load ranged from 371.3 to 1601.0 N, respectively, for 3 and 6 mm screws. The determinant coefficient was increased to R2=.421 when a linear relationship between pullout load and the SD/PW ratio was used. The peak loads of 1216 and 1288N were found for an SD/PW ratio of.83. Conclusion: We have found that the screw pullout load is more correlated to SD/PW than other pedicle measures for a maximized SD/PW ratio of.83. This particular value should be considered the upper limit of the indicated SD/PW ratio and a means to determine the optimal screw diameter to enhance pullout strength. [ABSTRACT FROM AUTHOR]

Pedicle screw fixation technique has been established as the safe standard for instrumentations in all spinal regions. However, the screw position is sometimes suboptimal. Cortical breaches may occur in different regions of the vertebrae. In addition to compromising bone purchase, pedicle perforations may endanger neural, vascular, and visceral structures. Moreover, a mispositioned screw can result in a greater risk of instrumentation failure. The accuracy of screw insertion has become a frequent topic of recent publications on spine surgery. Despite that, there is no unified way of reporting pedicle screws position. Several different scales are used. Given the multitude of used classifications and rarity of reported complications exact clinical relevance of pedicle screw misplacements remain unclear. In this article, the authors review types of scoring systems and propose a structured way for pedicle screw position grading based on a combination of the most used classifications.

This literature review aimed to review the current understanding, indications, and limitations of pedicle screw instrumentation cement augmentation. Since they were first reported in the 1980s, pedicle screw cement augmentation rates have been increasing. Several studies have been published to date that describe various surgical techniques and the biomechanical changes that occur when cement is introduced through the screw-bone interface. This article provides a concise review of the uses, biomechanical properties, cost analysis, complications, and surgical techniques used for pedicle screw cement augmentation to help guide physician practices. A comprehensive review of the current literature was conducted, with key studies, and contributions from throughout history being highlighted. Patients with low bone mineral density are the most well-studied indication for pedicle screw cement augmentation. Many studies show that cement augmentation can improve pullout strength in patients with low bone mineral density; however, the benefit varies inversely with pathology severity and directly with technique. The various screw types are discussed, with each having its own mechanical advantages. Cement distribution is largely dependent on the filling method and volume of cement used. Cement composition and timing of cement use after mixing are critical considerations in practice because they can significantly alter the bone-cement and screw-cement interfaces. Overall, studies have shown that pedicle screw cement augmentation has a low complication rate and increased pullout strength, justifying its universal use in patients with a suboptimal bone-implant interface.

SummarySpinopelvic dissociation injuries are complex injuries defined as discontinuity between the appendicular and axial skeleton. Fracture patterns are variable, but U-type and H-type fractures are common and often present with kyphotic deformity along with translational displacement and impaction. The ideal method of fixation has not been established for these injuries. The goals of treatment include restoration of alignment, stability, and neural decompression as needed. Traditional methods of lumbopelvic fixation have spanned the upper sacral fracture site. Our novel modified method of lumbopelvic fixation directly instruments the S1 body. This allows for direct manipulation of the fracture which we theorize improves reduction and increases stability across the fracture. This article characterizes the injury patterns, outlines the modified technique, and reports the clinical and radiographic outcomes of our modified lumbopelvic fixation technique and construct.

Lateral mass screw (LMS) and cervical pedicle screw (CPS) fixation are among the most popular techniques for posterior fusion of the cervical spine. Early research prioritized the LMS approach as the trajectory resulted in fewer neurovascular complications; however, with the incorporation of navigation assistance, the CPS approach should be re-evaluated. Our objective was to report the findings of a meta-analysis focused on comparing the LMS and CPS techniques in terms of rate of various complications with inclusion of all levels from C2 to T1. We conducted a systematic review of PubMed and EMBASE databases with final inclusion criteria focused on identifying studies that reported outcomes and complications for either the CPS or LMS technique. These studies were then pooled, and statistical analyses were performed from the cumulative data. A total of 60 studies comprising 4165 participants and 16,669 screws placed within the C2–T1 levels were identified. Within these studies, the LMS group had a significantly increased odds for lateral mass fractures (odds ratio [OR] = 43.2, 95% confidence interval [CI] = 2.62–711.42), additional cervical surgeries (OR = 5.56, 95%CI = 2.95–10.48), and surgical site infections (SSI) (OR = 5.47, 95%CI = 1.65–18.16). No other significant differences between groups in terms of complications were identified. Within the subgroup analysis of navigation versus non-navigation-guided CPS placement, no significant differences were identified for individual complications, although collectively significantly fewer complications occurred with navigation (OR = 5.29, 95%CI = 2.03–13.78). The CPS group had significantly fewer lateral mass fractures, cervical revision surgeries, and SSIs. Furthermore, navigation-assisted CPS placement was associated with a significant reduction in complications overall. [ABSTRACT FROM AUTHOR]

Pedicle screw fixation technique has been established as the safe standard for instrumentations in all spinal regions. However, the screw position is sometimes suboptimal. Cortical breaches may occur in different regions of the vertebrae. In addition to compromising bone purchase, pedicle perforations may endanger neural, vascular, and visceral structures. Moreover, a mispositioned screw can result in a greater risk of instrumentation failure. The accuracy of screw insertion has become a frequent topic of recent publications on spine surgery. Despite that, there is no unified way of reporting pedicle screws position. Several different scales are used. Given the multitude of used classifications and rarity of reported complications exact clinical relevance of pedicle screw misplacements remain unclear. In this article, the authors review types of scoring systems and propose a structured way for pedicle screw position grading based on a combination of the most used classifications. [ABSTRACT FROM AUTHOR]

Study Design. Retrospective Review. Objective. The objective of this study was to determine differences in surgical and post-operative outcomes in AIS patients undergoing spinal deformity correction surgery using standard or large pedicle screw size. Summary of Background. Use of pedicle screw fixation in spinal deformity correction surgery is considered safe and effective. Still, the small size of the pedicle and the complex 3D anatomy of the thoracic spine makes screw placement challenging, with improper pedicle screw fixation leading to catastrophic complications including injuries to nerve roots, spinal cord, and major vessels. Thus, insertion of larger diameter screw sizes has raised concerns amongst surgeons, especially in the pediatric population. Materials and Methods. AIS patients undergoing PSF between 2013 and 2019 were included. Demographic, radiographic, and operative outcomes collected. Patients in the large screw size group (GpI) received 6.5 mm diameter screw sizes at all levels while standard screw size group (GpII) received 5.0 to 5.5 mm diameter screw sizes at all levels. Kruskall-Wallis and Fisher's exact test performed for continuous and categorical variables respectively. Subanalyses included (1) screw accuracy in patients with available CT scans, (2) stratified analysis of large- and standard-screw patients with ≥ 60% flexibility rate, (3) stratified analysis of large- and standard-screw patients with <60% flexibility rate, and (4) matched analysis of large- and standard-screw patients by surgeon and year of surgery. Results. GpI patients experienced significantly higher overall curve correction (P<0.001), with 87.6% experiencing at least one grade reduction of apical vertebral rotation from preoperative to postoperative visit(P=0.008). Patients with larger screws displayed higher postoperative kyphosis. No patient experienced medial breaching. Conclusion. Large screw sizes have similar safety profiles to standard screws without negatively impacting surgical and perioperative outcomes in AIS patients undergoing PSF. Additionally, coronal, sagittal, and rotational correction is superior for largerdiameter screws in AIS patients. [ABSTRACT FROM AUTHOR]

This literature review aimed to review the current understanding, indications, and limitations of pedicle screw instrumentation cement augmentation. Since they were first reported in the 1980s, pedicle screw cement augmentation rates have been increasing. Several studies have been published to date that describe various surgical techniques and the biomechanical changes that occur when cement is introduced through the screw-bone interface. This article provides a concise review of the uses, biomechanical properties, cost analysis, complications, and surgical techniques used for pedicle screw cement augmentation to help guide physician practices. A comprehensive review of the current literature was conducted, with key studies, and contributions from throughout history being highlighted. Patients with low bone mineral density are the most well-studied indication for pedicle screw cement augmentation. Many studies show that cement augmentation can improve pullout strength in patients with low bone mineral density; however, the benefit varies inversely with pathology severity and directly with technique. The various screw types are discussed, with each having its own mechanical advantages. Cement distribution is largely dependent on the filling method and volume of cement used. Cement composition and timing of cement use after mixing are critical considerations in practice because they can significantly alter the bone-cement and screw-cement interfaces. Overall, studies have shown that pedicle screw cement augmentation has a low complication rate and increased pullout strength, justifying its universal use in patients with a suboptimal bone-implant interface. [ABSTRACT FROM AUTHOR]

Purpose: Finite element analysis is frequently used for lumbar spine biomechanical analysis. The primary scope of this work is to illustrate, using finite element analysis, how the biomechanical behavior of the transforaminal lumbar interbody fusion (TLIF), along with a novel combination of the interspinous process device (IPD) and pedicle screws, improves lumbar spine stability. Methods: In this study, unilateral pedicle screw fixation (UPSF) and bilateral pedicle screw fixation (BPSF) were used. Four FE models were developed using ANSYS software, as follows: (1) Intact model; (2) TLIF with "U"-shaped Coflex-F IPD (UCF); (3) TLIF with Coflex-F and UPSF (UCF + UPSF); (4) TLIF with Coflex-F and BPSF (UCF + BPSF). The intact model was subjected to four pure moments (10 Nm), and the results were validated with previous literature data. The intact model results correlated well with the literature data, and the model was validated. Three surgical models were subjected to 7.5 Nm four pure moments, flexion (FL), extension (ET), lateral bending (LB), and axial rotation (AR) and a 280N follower load. Results: The surgical model results were compared with the intact model. The comprehensive analysis results show the UCF + BPSF surgical model gave a good advantage on range of motion, cage stress, Coflex-F stress and endplate stress compared among the two models. Conclusion: This study proposes that the UCF + BPSF system helps to reduce the stress on the implant and adjacent endplates and gives very good stability to the lumbar spine under the various static loading conditions. [ABSTRACT FROM AUTHOR]

Objective To evaluate the clinical and radiological efficacy of a combine of lateral single screw-rod and unilateral percutaneous pedicle screw fixation (LSUP) for lateral lumbar interbody fusion (LLIF) in the treatment of spondylolisthesis. Methods Sixty-two consecutive patients with lumbar spondylolisthesis who underwent minimally invasive (MIS)-TLIF with bilateral pedicle screw (BPS) or LLIF-LSUP were retrospectively studied. Segmental lordosis angle (SLA), lumbar lordosis angle (LLA), disc height (DH), slipping percentage, the cross-sectional areas (CSA) of the thecal sac, screw placement accuracy, fusion rate and foraminal height (FH) were used to evaluate radiographic changes postoperatively. Visual analogue scale (VAS) and Oswestry Disability Index (ODI) were used to evaluate the clinical efficacy. Results Patients who underwent LLIF-LSUP showed shorter operating time, less length of hospital stay and lower blood loss than MIS-TLIF. No statistical difference was found between the 2 groups in screw placement accuracy, overall complications, VAS, and ODI. Compared with MIS-TLIF-BPS, LLIF-LSUP had a significant improvement in sagittal parameters including DH, FH, LLA, and SLA. The CSA of MIS-TLIF-BPS was significantly increased than that of LLIF-LSUP. The fusion rate of LLIF-LSUP was significantly higher than that of MIS-TLIF-BPS at the follow-up of 3 months postoperatively, but there was no statistical difference between the 2 groups at the follow-up of 6 months, 9 months, and 12 months. Conclusion The overall clinical outcomes and complications of LLIF-LSUP were comparable to that of MIS-TLIF-BPS in this series. Compared with MIS-TLIF-BPS, LLIF-LSUP for lumbar spondylolisthesis represents a significantly shorter operating time, hospital stay and lower blood loss, and demonstrates better radiological outcomes to maintain lumbar lordosis, and reveal an overwhelming superiority in the early fusion rate.

Objective The objective of this study was to evaluate the accuracy of pedicle screw placement in patients undergoing percutaneous pedicle screw fixation with robotic guidance, using a newly developed 3-dimensional quantitative measurement system. The study also aimed to assess the clinical feasibility of the robotic system in the field of spinal surgery. Methods A total of 113 patients underwent pedicle screw insertion using the CUVIS-spine pedicle screw guide system (CUREXO Inc.). Intraoperative O-arm images were obtained, and screw insertion pathways were planned accordingly. Image registration was performed using paired-point registration and iterative closest point methods. The accuracy of the robotic-guided pedicle screw insertion was assessed using 3-dimensional offset calculation and the Gertzbein-Robbins system (GRS). Results A total of 448 screws were inserted in the 113 patients. The image registration success rate was 95.16%. The average error of entry offset was 2.86 mm, target offset was 2.48 mm, depth offset was 1.99 mm, and angular offset was 3.07°. According to the GRS grading system, 88.39% of the screws were classified as grade A, 9.60% as grade B, 1.56% as grade C, 0.22% as grade D, and 0.22% as grade E. Clinically acceptable screws (GRS grade A or B) accounted for 97.54% of the total, with no reported neurologic complications. Conclusion Our study demonstrated that pedicle screw insertion using the novel robot-assisted navigation method is both accurate and safe. Further prospective studies are necessary to explore the potential benefits of this robot-assisted technique in comparison to conventional approaches.

Background: Percutaneous pedicle screw fixation [PPSF], where screws are inserted through small holes in the skin, has become a popular approach for treating thoracolumbar and lumbar fractures. It has been shown to produce satisfactory outcomes.Aim of the work: The aim was to examine the procedure and assess the practicality, safety and results of using PPSF to treat thoracolumbar fractures.Patients and Methods: A prospective cohort study included 20 patients with thoracic or lumbar spine fracture, without neurological deficit, whom were operated upon by percutaneous screw fixation, and were assessed clinically [for improvement and development of complications] and radiologically [for healing and correction of deformity] by follow up over 6 months after surgery.Results: All cases achieved full radiological union by 3 months. The mean union time in our cohort was 2.1±0.5 months. Postoperatively, a statistically significant improvement in the vertebral kyphotic angle to a mean value of 4.7 ± 2.3 was observed [Bonferroni post-hoc test, P = 0.001]. The correction was maintained till last follow-up. Two patients [10%] developed incomplete paraplegia [Frankel grade D]. Misplacement of the pedicle screws was recorded in 6 of 90 screws in six patients.Conclusion: The PPSF is a valuable surgical procedure for patients with thoracic and lumbar vertebral fracture.

Objective To compare the efficacy of oblique lateral interbody fusion (OLIF), OLIF combined with anterolateral screw fixation (OLIF-AF), and OLIF combined with percutaneous pedicle screw fixation (OLIF-PF) in the treatment of single-level or 2-level degenerative lumbar disease. Methods Between January 2017 and 2021, 71 patients were treated with OLIF and combined OLIF. The demographic data, clinical outcomes, radiographic outcomes, and complications were compared among the 3 groups. Results The operative time and intraoperative blood loss in the OLIF (p0.05) or between the OLIF and OLIF-AF groups (p>0.05). There were no significant differences in fusion rates, the incidence of complications, lumbar lordosis, anterior disc height, and cross-sectional area among the 3 groups (p>0.05). The OLIF-PF group had significantly lower rates of subsidence than the OLIF group (p

Objective It is clinically important for pedicle screws to be placed quickly and accurately. Misplacement of pedicle screws results in various complications. However, the incidence of complications varies greatly due to the different professional titles of physicians and surgical experience. Therefore, physicians must minimize pedicle screw dislocation. This study aims to compare the three nail placement methods in this study, and explore which method is the best for determining the anatomical landmarks and vertical trajectories. Methods This study involved 70 patients with moderate idiopathic scoliosis who had undergone deformity correction surgery between 2018 and 2021. Two spine surgeons used three techniques (preoperative computed tomography scan [CTS], visual inspection‐X‐freehand [XFH], and intraoperative detection [ID] of anatomical landmarks) to locate pedicle screws. The techniques used include visual inspection for 287 screws in 21 patients, preoperative planning for 346 screws in 26 patients, and intraoperative probing for 309 screws in 23 patients. Observers assessed screw conditions based on intraoperative CT scans (Grade A, B, C, D). Results There were no significant differences between the three groups in terms of age, sex, and degree of deformity. We found that 68.64% of screws in the XFH group, 67.63% in the CTS group, and 77.99% in the ID group were placed within the pedicle margins (grade A). On the other hand, 6.27% of screws in the XFH group, 4.33% in the CTS group, and 6.15% in the ID group were considered misplaced (grades C and D). The results show that the total amount of upper thoracic pedicle screws was fewer, meanwhile their placement accuracy was lower. The three methods used in this study had similar accuracy in intermediate physicians (P > 0.05). Compared with intermediate physicians, the placement accuracy of three techniques in senior physicians was higher. The intraoperative detection group was better than the other two groups in the good rate and accuracy of nail placement (P

Study Design This study was a retrospective case series. Purpose This study was designed to determine whether direct vertebral rotation (DVR) of the lowest instrumented vertebra (LIV) using a high-density (HD) construct can reduce fusion segments without increasing adverse outcomes in selective thoracic fusion (STF) for adolescent idiopathic scoliosis (AIS). Overview of Literature LIV DVR is used to maximize spontaneous lumbar curve correction and reduce adverse outcomes during STF for AIS. However, evidence is limited on whether LIV DVR can allow a proximally located LIV and reduce fusion segments without increasing adverse outcomes. Methods We reviewed consecutive patients with Lenke 1 AIS who underwent STF from 2000 to 2017. The patients were divided into two groups based on the surgical strategy used: low-density (LD) construct without DVR of the LIV (LD group) versus HD construct with DVR of the LIV (HD group). We collected data on the patient’s demographic characteristics, skeletal maturity, operative data, and measured radiological parameters in the preoperative and final follow-up radiographs. The occurrence of adding-on (AO) and coronal decompensation was also determined. Results In this study, 72 patients (five males and 67 females) with a mean age of 14.1±2.3 years were included. No significant differences in the demographics, skeletal maturity, and Lenke type distribution were observed between the two groups; however, the follow-up duration was significantly longer in the LD group (64.3±25.7 months vs. 40.7±22.2 months, p

This study was designed to systematically review and meta-analyze the functional and radiological outcomes between lateral and posterior approaches in adult degenerative scoliosis (ADS). Both lateral (lumbar, extreme, and oblique) and posterior interbody fusion (posterior lumbar and transforaminal) are used for deformity correction in patients with ADS with unclear comparison in this cohort of patients in the existing literature. A literature search using three electronic databases was performed to identify studies that reported outcomes of lateral (group L) and posterior interbody fusion (group P) in patients with ADS with curves of 10°–40°. Group P was further subdivided into minimally invasive surgery (MIS-P) and open posterior (Op-P) subgroups. Data on functional, radiological, and operative outcomes, length of hospital stay (LOHS), fusion rates, and complications were extracted and meta-analyzed using the random-effects model. A total of 18 studies (732 patients) met the inclusion criteria. No significant difference was found in functional and radiological outcomes between the two groups on data pooling. Total operative time in the MIS-P subgroup was less than that of group L (233.86 minutes vs. 401 minutes, p

Percutaneous pedicle screw fixation (PSF) has emerged as a promising alternative to traditional open surgical approaches for spinal stabilization. Pedicle screws are inserted through percutaneous access sites without substantial soft tissue dissection. To ensure proper screw insertion, the procedure employs fluoroscopic or imageguided navigation devices. The popularity of percutaneous PSF has accelerated because of its prospective advantages and the mounting body of research demonstrating its effectiveness and safety. However, there are a few drawbacks to the procedure, such as a longer learning curve for surgeons, poor visibility when inserting screws, and a requirement for specialized tools and imaging guiding systems. This article provides a comprehensive review of the technique of percutaneous PSF, its clinical outcomes, and recent advancements in the field. It also aims to analyze the efficacy, safety, and limitations of percutaneous PSF, as well as explore the evolving technologies and techniques that have contributed to its improved application. [ABSTRACT FROM AUTHOR]

Lumbar spondylolisthesis is a prevalent cause of lower back pain and is a focal interest of spinal surgery. A diverse set of decompression and fusion techniques are used in surgery. To investigate the surgical and clinical outcomes patients with spondylolisthesis who received surgical intervention. Data from 25 patients (15 women; 10 men; mean age, 48.8 ± 12.4 years; range, 27–66 years) with low-grade spondylolisthesis who received surgical intervention were retrospectively analyzed. Posterolateral and posterior interbody fusion was used in 17 and 8 patients, respectively, and 19 received posterior pedicle screws and 6 received only fusion and decompression. According to the Kirkaldy–Willis criteria, the clinical outcomes of 11 (44%), 9 (36%), 3 (12%), and 2 (8%) patients were rated excellent, good, fair, and poor, respectively, with a success rate of 80%. Furthermore, fusion was observed in 21 patients (84%). Favorable outcomes were achieved in 17 (90%) patients with pedicle screws and in 3 (50%) with only decompression and fusion (p=0.048; p<0.05). The rate of favorable outcome was 75% of patients who smoked (p=0.226; p>0.05). Two out of three patients with revision surgery had poor clinical outcomes (p=0.091; p<0.05). The addition of pedicle screw fixation to posterolateral fusion increases fusion rates and yields satisfactory clinical results. Previous history of surgery is a risk factor that should be considered before deciding to perform surgery. Furthermore, the transpedicular screw fixation technique can be made less complicated and effective via effective and experienced teamwork. Herein, we reviewed recent studies and discussed the indications, complications, and outcomes of surgical treatment of low-grade spondylolisthesis. [ABSTRACT FROM AUTHOR]

Objective To observe the clinical efficacy of thoracic and lumbar pedicle screw fixation combined with hemivertebra resection in the treatment of congenital scoliosis caused by hemivertebra in young children, and to analyze the accuracy of screw placement. Methods Nineteen children with congenital scoliosis due to hemivertebra were enrolled, including 11 males and 8 females, aged 1-9 years. Posterior median approach was adopted for pedicle screw fixation, hemivertebra resection and bone graft fusion. The fixation segment of the pedicle screw was from the 1st thoracic vertebral body to the 5th lumbar vertebral body （T1-L5). During the operation, the pedicle screw was placed by free hand ac‐ cording to the positioning of the C-arm and anatomical landmarks. According to the distance of the pedicle screw penetrating the interior, lateral or anterior sides of the vertebral body （including the pedicle) cortical bone, we graded and recorded the screw placement at each level. Coronal plane parameters （total scoliosis angle, segmental scoliosis angle, cephalic compensatory curve, caudal compensatory curve, apical vertebral offset, and coronal plane balance) and sagittal plane parameters （thoracic kyphosis, lumbar lordosis, segmental kyphosis, and sagittal plane balance) were used to evaluate clini‐ cal efficacy, and we recorded intraoperative or postoperative complications related to pedicle screw placement. Results The operation time of children in this group was （253±55) min, and the blood loss was （239±85) mL. Single hemivertebra was removed in 9 cases, and 2 hemivertebra were removed in 2 cases. A total of 120 pedicle screws were placed, 103 screws were correctly placed （85. 8%), and 17 screws were abnormally placed （14. 2%). The rate of abnormal screw placement in the thoracic region was higher than that in the lumbar region （P<0. 01). The coronal total scoliosis angle, segmental scoliosis angle, cephalic compensatory curve, caudal compensatory curve and sagittal plane segmental kyphosis were lower than those before operation （all P<0. 01). The immediate correction rates were 78. 8%, 76. 6%, 62. 9%, 71. 7%, and 68. 2%, respectively. During the follow-up, a small amount was lost, and the cephalic compensatory curve was corrected by 0. 2°±1. 0°； postoperative apical vertebral offset, coronal plane balance, and sagittal plane balance were smaller than those before operation （all P<0. 01). During the operation and postoperative follow-up, no complications re‐ lated to the nervous system occurred, and no complications related to pedicle screw placement occurred. Conclusions Thoracic and lumbar pedicle screw fixation combined with hemivertebra resection for congenital scoliosis due to hemiverte‐ bra in young children can achieve satisfactory clinical results, and there are fewer postoperative complications related to pedicle screw placement. However, the risk of misplacement of screws in the thoracic region is higher than that in the lum‐ bar region, so attention should be paid to risk prevention and control. [ABSTRACT FROM AUTHOR]

To assess agreement between pedicle screw placement evaluated on postoperative computed tomography (CT) and on intraoperative cone-beam CT (CBCT) and compare procedure characteristics when using first-generation and second-generation robotic C-arm systems in the hybrid operating room. All patients who received pedicle screws for spinal fusion at our institution between June 2009 and September 2019 and underwent intraoperative CBCT and postoperative CT were included. The CBCT and CT images were reviewed by 2 surgeons to assess the screw placement using the Gertzbein-Robbins and the Heary classifications. Intermethod agreement of screw placement classifications as well as interrater agreement were assessed using Brennan-Prediger and Gwet agreement coefficients. Procedure characteristics using first-generation and second-generation generation robotic C-arm systems were compared. Fifty-seven patients were treated with 315 pedicle screws at thoracic, lumbar, and sacral levels. No screw had to be repositioned. On CBCT, accurate placement was found for 309 screws (98.1%) using the Gertzbein-Robbins classification and 289 (91.7%) using the Heary classification and on CT, these were 307 (97.4%) and 293 (93.0%), respectively. Intermethod between CBCT and CT and interrater agreements between the 2 raters were almost perfect (>0.90) for all assessment. There were no significant differences in mean radiation dose (P = 0.83) and fluoroscopy time (P = 0.82), but length of surgery using the second-generation system was estimated at 107.7 minutes (95% confidence interval, 31.9–183.5 minutes; P = 0.006) shorter. Intraoperative CBCT provides accurate assessment of pedicle screw placement and enables intraoperative repositioning of misplaced screws. [ABSTRACT FROM AUTHOR]

Interbody fusions have become increasingly popular to achieve good fusion rates. Also, unilateral instrumentation is favored to minimize soft tissue injury with limited hardware. Limited finite element studies are available in the literature to validate these clinical implications. A three-dimensional, non-linear ligamentous attachment finite element model of L3-L4 was created and validated. The intact L3-L4 model was modified to simulate procedures like laminectomy with bilateral pedicle screw Instrumentation, transforaminal, and posterior lumbar interbody fusion (TLIF and PLIF, respectively) with unilateral and bilateral pedicle screw instrumentation. Compared to instrumented laminectomy, interbody procedures showed a considerable reduction in range of motion (RoM) in extension and torsion (6% and 12% difference, respectively). Both TLIF and PLIF showed comparable RoM in all movements with < 5% difference in reduction of RoM between them. Bilateral instrumentation showed a more significant decrease in RoM (> 5% difference) in the entire range of motion except in torsion when compared to unilateral instrumentation. The maximum difference in reduction in RoM was noted in lateral bending (24% and 26% for PLIF and TLIF, respectively), while the least difference in Left torsion (0.6% and 3.6% for PLIF and TLIF, respectively) in comparing bilateral with unilateral instrumentation. Interbody fusion procedures were found to be biomechanically more stable in extension and torsion than the instrumented laminectomy. Single-level TLIF and PLIF achieved a similar reduction in RoM with a < 5% difference. Bilateral screw fixation proved biomechanically superior to unilateral fixation in the entire range of motion except in torsion. [ABSTRACT FROM AUTHOR]

Study Design.: A retrospective cohort study. Objective.: To determine if there is a difference in reoperation rates for symptomatic adjacent segment disease (operative ASD) and symptomatic nonunions (operative nonunions) in posterior cervical fusions (PCFs) stopping at C7 using either lateral mass screws (LMS) or cervical pedicle screws (CPS) at C7. Summary of Background Data.: Stopping PCFs at C7 has been controversial because of the risks of adjacent segment disease or nonunions. The two commonly used fixation techniques at the C7 level are LMS and CPS. Materials and Methods.: A retrospective analysis from the Kaiser Permanente Spine Registry identified a cohort of patients with cervical degenerative disk disease who underwent primary PCFs stopping at C7 with either LMS or CPS at C7. Demographic and operative data were extracted from the registry, and operative ASD and operative nonunions were adjudicated through chart review. Patients were followed until validated operative ASD or nonunion, membership termination, death, or end of study (March 31, 2022). Descriptive statistics and multivariable Cox proportional hazards models were calculated for operative ASDs and operative nonunions. Results.: We found 481 patients with PCFs stopping at C7 with either LMS (n=347) or CPS (n=134) at C7 with an average follow-up time of 5.6 (±3.8) years, time to operative ASD of 3.0 (±2.8) years, and to operative nonunion of 1.2 (±0.7) years. There were 11 operative ASDs (LMS=8, CPS=3) and eight operative nonunions (LMS=4, CPS=4). There was no statistical difference between patients stopping at C7 with LMS versus CPS for operative ASDs (HR: 0.68, 95% CI=0.17–2.77, P =0.60) or operative nonunions (HR: 2.09, 95% CI=0.45–8.58, P =0.37). Conclusion.: A large cohort of patients with PCFs stopping at C7 with an average follow-up of > 5 years found no statistical difference in reoperation rates for symptomatic ASD (operative ASD) or operative nonunion using either LMS or CPS at C7. [ABSTRACT FROM AUTHOR]

Case series summary: A 1-year-old castrated male Maine Coon cat was referred because of a 1-week history of progressive spastic non-ambulatory paraparesis. An MRI examination of the thoracolumbar spine showed multiple lytic lesions, with the most aggressive one centred on the adjacent endplates of L1–L2 and its associated disc. Ventral new bone formation, L1 vertebral body shortening and mild dorsal displacement of the caudal aspect of L1 were noted. Contrast enhancement of both paravertebral soft tissue and extradural lesion was present. These findings were compatible with L1–L2 discospondylitis (DS), spinal epidural empyema (SEE), with secondary L1 pathological vertebral fracture, subluxation and spinal cord compression. CT of the thoracolumbar spine, abdomen and thorax confirmed these findings. The patient deteriorated to paraplegia with absent nociception, despite initial medical therapy. A right-sided L1–L2 hemilaminectomy and spinal decompression were then performed, followed by application of a unilateral construct comprising four smooth arthrodesis wires and polymethylmethacrylate (PMMA). S taphylococcus aureus was isolated from both epidural material, intraoperatively sampled and blood culture. Antibiotic therapy was continued for 6 weeks, based on susceptibility results. The outcome was excellent, with a gradual improvement and complete neurological recovery at the 8-week postoperative check. Repeated spinal radiographs showed an intact apparatus and marked signs of vertebral fusion. At the 14-month follow-up examination, the cat remained free of clinical signs. Relevance and novel information: To the authors' knowledge, this is the first case report of SEE and DS in a cat that required surgical stabilisation. The outcome was still optimal, despite the rapid neurological deterioration. [ABSTRACT FROM AUTHOR]