Modified pedicle screw-rod fixation versus open reduction plate fixation for the management of pubic symphysis diastasis: A retrospective study.

Objective: Surgical intervention and fixation is the recognized measurement to treat pubic symphysis diastasis caused by high-energy trauma. The purpose of this retrospective study was to assess the clinical application of modified pedicle screw-rod fixation (modified PSRF) and open reduction plate fixation (ORPF) for treating pubic symphysis diastasis. Methods: The data of this retrospective analysis were collected from 32 patients with pubic symphysis diastasis managed with modified PSRF or ORPF from January 2012 to December 2017, with or without posterior fixation. Indicators of clinical assessments including operating time, intraoperative blood loss, relevant surgical complications as well as follow-up were recorded. Majeed scores were performed for functional evaluation, as well as Matta criteria were applied to evaluate the quality of reduction. Results: The average time from injury to operation was 2.9 days in modified PSRF group and 3.2 days in ORPF group. Significant differences regarding average operation time (41.8 min versus 64.3 min) and average intraoperative blood loss (46.6 ml versus 304.6 ml) were presented between modified PSRF groups and ORPF group. Neither Majeed scores nor Matta evaluation showed a significant difference between two groups. In ORPF group, the incision infection occurred in one patient and two patients developed loosening of screws. In modified PSRF group, loosening of screws was found in one patient during the operative procedure and one patient experienced femoral nerve palsy. Irritation to the lateral femoral cutaneous nerve (LFCN) was detected in two patients in modified PSRF group. Conclusions: Satisfactory clinical outcomes were provided with applications of both fixation methods for treating pubic symphysis diastasis. Modified PSRF, as a minimal invasive technique, could serve as an effective and reasonable option for treating pubic symphysis diastasis.Level of evidence: III: retrospective cohort study.Trial registration: researchregistry3906.

[Oblique Lumbar Interbody Fusion Combined With 4-Screw Fixation for Treating Two-Level Degenerative Lumbar Diseases:A Finite Element Study].

Objective To demonstrate the feasibility of oblique lumbar interbody fusion (OLIF) combined with 4-screw fixation for treating two-level lumbar degenerative diseases.Methods An intact finite element model of L3-S1 (M0) was constructed and validated.Then,we constructed the M1 model by simulating OLIF surgery at L3/4 and L4/5 segments on the M0 model.By attachment of posterior 4-screw or 6-screw fixation to the M1 model,three 4-screw fixation models (M2-M4) and one 6-screw fixation model (M5) were established.The segmental and overall range of motion (ROM) and the peak von Mises stresses of superior endplate,cage,and posterior screw-rod were investigated under each implanted condition.Results Under the motion modes of forward flexion,backward extension,bilateral (left and right) flexion,and left and right rotation,the L3/4 ROM of M2 model and L4/5 ROM of M3 model increased,while the L3/4 and L4/5 ROM of M4 and M5 models significantly decreased compared with those of M1 model.Under all motion modes,the L4 superior endplate in M2 model and the L5 superior endplate in M3 model showed the maximum peak von Mises stress,and the peak von Mises stresses of L4 and L5 superior endplates in M4 and M5 models were close.The L3/4 cage in M2 model and the L4/5 cage in M3 model showcased the largest peak von Mises stress,and the peak von Mises stresses of cages in M4 and M5 models were close.The peak stresses of internal fixation in M2-M5 models were close.Conclusion Four-screw fixation can replace 6-screw fixation in the OLIF surgery for treating two-level degenerative lumbar diseases.

A Novel Two-Step Method for Converting Lumbar Cortical Screw to Pedicle Screw: A Case Report.

The cortical bone trajectory (CBT) technique has emerged as a minimally invasive approach for lumbar fusion but may result in pseudoarthrosis and hardware failure. This report presents a case of successful pedicle screw revision in a patient with previous failed L2 and L3 fusion using a novel "two-step" technique, including (1) drilling a new trajectory with Medtronic EM800N Stealth MIDAS Navigated MR8 drill system (Medtronic, Dublin, Ireland) and (2) placement of Solera 4.75 ATS (awl-tapped screws) with navigated POWEREASE™ (Medtronic), described here for the first time. This method involves utilizing neuronavigation and specialized instruments to safely place pedicle screws through the path of the old cortical screw trajectory, addressing the challenges associated with CBT hardware failure.

Perioperative complications associated with fluoroscopy C1 lateral mass screw fixation (Goel technique) versus computed tomography-guided navigation technique: A review of 202 cases from the German Spine Registry (DWG-Register).

Background: Overview of the literature - Fractures of the C1 constitute 3%-13% of all cervical spine injuries in adults. Most isolated C1 fractures are stable and can be treated nonoperatively with external immobilization. Traditional surgical options for C1 fracture treatment are occiput-to-C2 fusion or C1 with lateral mass screws (LMSs). Purpose - The aim is to assess the management and perioperative complications of C1 fractures undergoing LMS fusion between fluoroscopy and computed tomography (CT)-guided navigation. Methods: This was a retrospective multicenter study of data from the DWG-Register of patients who underwent operative treatment for C1 traumatic fracture with LMSs from January 2017 to September 2022. Inclusion criteria - traumatic injury and age > 18 years old. Results: In total, 202 patients with traumatic C1 fracture requiring spinal surgery were identified in the registry; n = 175 (Group 1) were treated conventionally without CT-guided navigation and n = 27 were treated with CT-guided navigation (Group 2). C1-LMS was principally performed by spine surgeons n = 90 (53.4%) and n = 72 (18.5%) by neurosurgeons in both the groups. Intraoperative adverse events were as follows: dural tear in group 1 n = 0 and in group 2 n = 1, vascular injury, with one case in group 1 and no cases in group 2. General complications were: cardiovasculars in group 1 n = 6 (3.4%) and Group 2 n = 4 (14.8%) (P = 0.03), pulmonary complications in group1 n = 2 (1.1%) and n = 9 in group 2 (33.3%) (P < 0.001), stroke n = 1 (0.57%) in group1 and n = 4 in group 2 (14.8%) (P < 0.001), gastrointestinal bleeding n = 1 (0.57%) in group1 and no cases in group 2, renal insufficiency n = 2 (1.1%) in group 1 and n = 3 (11.1%) in group 2 (P = 0.01). One death was recorded in group 2 (3.7%). Conclusion: This series of 404 screws placed in 202 patients over 5 years who underwent two types of C1 fracture fixation had a considerably lower incidence of screw malposition and vertebral artery injury than has previously been reported in the literature. C1 screws can be safely placed with a low risk of vertebral artery and neurologic injury with and without CT-guided navigation support.

Fully automated determination of robotic pedicle screw accuracy and precision utilizing computer vision algorithms.

Historically, pedicle screw accuracy measurements have relied on CT and expert visual assessment of the position of pedicle screws relative to preoperative plans. Proper pedicle screw placement is necessary to avoid complications, cost and morbidity of revision procedures. The aim of this study was to determine accuracy and precision of pedicle screw insertion via a novel computer vision algorithm using preoperative and postoperative computed tomography (CT) scans. Three cadaveric specimens were utilized. Screw placement planning on preoperative CT was performed according to standard clinical practice. Two experienced surgeons performed bilateral T2-L4 instrumentation using robotic-assisted navigation. Postoperative CT scans of the instrumented levels were obtained. Automated segmentation and computer vision techniques were employed to align each preoperative vertebra with its postoperative counterpart and then compare screw positions along all three axes. Registration accuracy was assessed by preoperatively embedding spherical markers (tantalum beads) to measure discrepancies in landmark alignment. Eighty-eight pedicle screws were placed in 3 cadavers' spines. Automated registrations between pre- and postoperative CT achieved sub-voxel accuracy. For the screw tip and tail, the mean three-dimensional errors were 1.67 mm and 1.78 mm, respectively. Mean angular deviation of screw axes from plan was 1.58°. For screw mid-pedicular accuracy, mean absolute error in the medial-lateral and superior-inferior directions were 0.75 mm and 0.60 mm, respectively. This study introduces automated algorithms for determining accuracy and precision of planned pedicle screws. Our accuracy outcomes are comparable or superior to recent robotic-assisted in vivo and cadaver studies. This computerized workflow establishes a standardized protocol for assessing pedicle screw placement accuracy and precision and provides detailed 3D translational and angular accuracy and precision for baseline comparison.

The Utility and Feasibility of Smart Glasses in Spine Surgery: Minimizing Radiation Exposure During Percutaneous Pedicle Screw Insertion.

OBJECTIVE: Spine surgeons are often at risk of radiation exposure due to intraoperative fluoroscopy, leading to health concerns such as carcinogenesis. This is due to the increasing use of percutaneous pedicle screw (PPS) in spinal surgeries, resulting from the widespread adoption of minimally invasive spine stabilization. This study aimed to elucidate the effectiveness of smart glasses (SG) in PPS insertion under fluoroscopy. METHODS: SG were used as an alternative screen for fluoroscopic images. Operators A (2-year experience in spine surgery) and B (9-year experience) inserted the PPS into the bilateral L1-5 pedicles of the lumbar model bone under fluoroscopic guidance, repeating this procedure twice with and without SG (groups SG and N-SG, respectively). Each vertebral body's insertion time, radiation dose, and radiation exposure time were measured, and the deviation in screw trajectories was evaluated. RESULTS: The groups SG and N-SG showed no significant difference in insertion time for the overall procedure and each operator. However, group SG had a significantly shorter radiation exposure time than group N-SG for the overall procedure (109.1 ± 43.5 seconds vs. 150.9 ± 38.7 seconds; p = 0.003) and operator A (100.0 ± 29.0 seconds vs. 157.9 ± 42.8 seconds; p = 0.003). The radiation dose was also significantly lower in group SG than in group N-SG for the overall procedure (1.3 ± 0.6 mGy vs. 1.7 ± 0.5 mGy; p = 0.023) and operator A (1.2 ± 0.4 mGy vs. 1.8 ± 0.5 mGy; p = 0.013). The 2 groups showed no significant difference in screw deviation. CONCLUSION: The application of SG in fluoroscopic imaging for PPS insertion holds potential as a useful method for reducing radiation exposure.

Early Extrusion of an Anterior Odontoid Screw: A Case Report.

Odontoid fractures in the elderly typically require surgical intervention due to poor adaptability to conservative treatment. Anterior screw fixation, despite its high fusion rates under specific conditions, may lead to complications such as screw extrusion, as demonstrated in the case discussed, necessitating subsequent posterior cervical fusion. This study aimed to describe early extrusion of an anterior odontoid screw and the importance of caution and thorough postoperative assessment in elderly patients undergoing anterior screw fixation for odontoid fracture. A 73-year-old female patient with a history of ground-level fall and subsequent cervical pain was diagnosed with an odontoid type II fracture and underwent odontoid screw placement in June 2023. However, in August, follow-up imaging revealed screw displacement and a fracture of the posterior arch of the C1 vertebral, which was initially overlooked. After seeking a second opinion, a new surgical approach was decided, involving removal and replacement of the odontoid screw, posterior and posterolateral C1-C2 spinal instrumentation, arthrodesis, and fusion with the use of morselized allograft. The patient was discharged on postoperative day 3 with mild cervical pain, wearing a soft collar, and neurologically intact. Given the current literature, odontoid screw extrusion rates are still small but can come with enormous potential complications. Also, the present case is a reminder to always double-check preoperative imaging and recognize early failure/malpositioning of hardware.

Novel MRI-Based Pedicle Bone Quality Score Independently Predicts Pedicle Screw Loosening after Degenerative Lumbar Fusion Surgery.

Pedicle screw loosening after posterior lumbar fusion is associated with poor bone quality, which often determines screw pull-out strength, insertion torque, and vertebral body loading characteristics. Magnetic resonance imaging (MRI)-based vertebral bone quality (VBQ) score were associated with poor bone quality. Current evidence suggests that pedicle bone quality (PBQ) has a greater impact on screw stability. However, the correlation between MRI-based PBQ score and screw loosening has not been reported. PURPOSE: To introduce and evaluate an MRI-based PBQ score to determine its effectiveness in predicting pedicle screw loosening following lumbar fusion surgery. METHODS: The retrospective study analyzed 244 patients who underwent posterior lumbar interbody fusion (PLIF) with pedicle screws between December 2017 and December 2021, with CT and MRI imaging before surgery. Data collected included patient demographics and preoperative radiological data. Radiographic screw loosening was measured at 12 months postoperatively. Clinical assessments included pain visual analog scale (VAS) and Oswestry Disability Index (ODI) scores. The PBQ score was measured using MRI scans. We use univariate analysis for preliminary screening of the risk factors of screw loosening. Subsequent analysis involved multivariate logistic regression to identify independent predictive factors for screw loosening. We constructed the receiver operating characteristic (ROC) curve to ascertain the discriminative capacity of the PBQ score. The area under the curve (AUC) quantified its predictive accuracy. Additionally, we evaluated the association between PBQ score and screw loosening using Spearman's correlation analysis. RESULTS: Overall, 244 patients who underwent PLIF with pedicle screw fixation participated in this study, including 35 in the loosening group and 209 in the non-loosening group. PBQ score in the loosening group was significantly higher than that in the non-loosening group. On multivariate logistic regression, the higher PBQ score (OR = 8.481, 95% CI: 3.158-22.774; p < 0.001) and the lower mean Hounsfield unit (HU) value of L1-4 (OR = 0.967, 95% CI 0.951-0.984; p < 0.001) were the variables that significantly predicted screw loosening. The AUC for the PBQ score and HU value were 0.751 (95% CI: 0.673-0.828) and 0.702 (95% CI: 0.612-0.791). The PBQ score optimal cutoff to differentiate patients with loosening and with non-loosening was calculated as 3.045 with a sensitivity of 85.7% and specificity of 76.9%, while the optimal cutoff of the HU value was 151.5 with a sensitivity of 64.6% and specificity of 89.5%. CONCLUSIONS: The association between the PBQ score and the propensity for lumbar pedicle screw loosening was found to be substantial. As a predictive measure, the PBQ score outperformed the HU value in forecasting the likelihood of screw loosening post-posterior lumbar fusion.

Precision control and parameter optimization in screw extrusion 3D printing of polypropylene materials.

Fused Deposition Modeling (FDM), a widely-utilized additive manufacturing (AM) technology, has found significant favor among automotive manufacturers. Polypropylene (PP) compound is extensively employed in the production of automotive parts due to its superior mechanical properties and formability. However, aiming at the problem of poor dimensional accuracy of pure PP parts, the quality of products can be enhanced by optimizing the combination of processing parameters. In this paper, the dimensional accuracy of 3D-printed components made from pure PP material is investigated. Key influencing factors such as infill percentage, infill pattern, layer thickness, and extrusion temperature are considered. To gain a deeper understanding, fluid simulation is conducted, and mathematical models are established to correlate processing parameters with dimensional accuracy. Furthermore, the Taguchi's experiments are designed and the experimental data are subjected to rigorous Signal-to-Noise ratio and ANOVA analyses. Within the experimental range, the lower extrusion temperature, infill percentage and layer thickness yield the best dimensional accuracy. Considering the influence factors of X, Y and Z directions, the optimal processing parameters for PP prints using screw extrusion 3D printers are determined as follows: an extrusion temperature of 210 °C, an infill percentage of 40 %, a layer thickness of 0.3 mm, and a concentric circle infill pattern. This study provides reference value for the subsequent improvement of the dimensional accuracy of the printed parts.

Deformity correction from the convexity of the curve in neuromuscular scoliosis.

Background: "Convex Pedicle Screw Technique" reduces the theoretical risk of neurovascular injury. Our aim is to evaluate the efficacy of this technique in patients with neuromuscular scoliosis (NMS). Methods: Retrospective study of 12 patients who underwent a Convex Pedicle Screw Technique and were diagnosed with NMS. Patients who had undergone previous spinal surgery were excluded. The minimum follow-up required was 24 months. Demographic data, intraoperative data, neurovascular complications and neurophysiological events requiring implant repositioning, as well as pre- and postoperative radiological variables were collected. Results: Twelve patients diagnosed with NMS underwent surgery. The median operative time was 217 minutes. Mean blood loss was 3.8±1.1 g/dL hemoglobin (Hb). The median postoperative stay was 8.8±4 days. A reduction of the Cobb angle in primary curve of 49.1% (from 52.8°±18° to 26.5°±12.6°; P<0.001) and in secondary curve of 25.2% (from 27.8°±18.9° to 18.3°±13.3°; P=0.10) was achieved. Coronal balance improved by 69.4% (7.5±46.2 vs. 2.3±20.9 mm; P=0.72) and sagittal balance by 75% (from -14.1±71.8 vs. -3.5±48.6 mm; P=0.50). There were no neurovascular complications. There were no intraoperative neurophysiological events requiring implant repositioning, nor during reduction maneuvers. No infections were reported. Conclusions: The correction of the deformity from convexity in NMS achieves similar results to other techniques, and a very low complication rate.

Oblique Lumbar Interbody Fusion Combined with Posterior Percutaneous Pedicle Screw Internal Fixation: Does Variability in Cage Position Influence Clinical Outcomes?

OBJECTIVE: The study investigates how cage positions in oblique lumbar interbody fusion (OLIF) combined with posterior percutaneous pedicle screw internal fixation (PPSF) affect lumbar canal and foraminal decompression and postoperative outcomes, providing guidance for optimal placement and efficacy assessment. METHODS: This investigation assesses radiological outcomes and follow-up data in relation to cage position variability among 80 patients who underwent L4/5 single-segment OLIF+PPSF from 2018-2022. RESULTS: In the study, involving 80 participants, the combination of OLIF and PPSF significantly improved lower back and leg symptoms in patients, leading to positive clinical outcomes during follow-up. The intervertebral DH increased from an average of 8.10 ± 2.79 mm before surgery to 11.75 ± 2.14 mm after surgery (P < 0.001). Additionally, this surgical technique notably increased the FH (P < 0.001) and expanded the DCSA from 68.81 ± 53.89 mmˆ2 before surgery to 102.91 ± 60.46 mmˆ2 after surgery (P < 0.001). Linear results suggest that changes in the position of the cage do not affect spinal imaging parameters. There is no significant difference in the correction of spinal parameters or prognosis whether the cage is back, middle, ahead. CONCLUSION: In the OLIF+PPSF procedure, strict requirements for cage position are not necessary to achieve predetermined spinal biomechanical parameters. The practice of repeated fluoroscopy to adjust cage position post-implantation does not provide added clinical benefits to the patient.

Biomechanical Comparison of Corticopedicular Spine Fixation versus Pedicle Screw Fixation in a Lumbar Degenerative Spondylolisthesis Finite Element Analysis Model.

OBJECTIVE: To compare the stability of a corticopedicular posterior fixation (CPPF) device to traditional pedicle screws for decompression and fusion in adult degenerative lumbar spondylolisthesis. METHODS: Finite element analysis (FEA) was used in a validated model of grade 1 L4-L5 spondylolisthesis to compare segmental stability following laminectomy alone, laminectomy with pedicle screw fixation, or laminectomy with CPPF device fixation. A 500N follower load was applied to the model and different functional movements were simulated by applying a 7.5Nm force in different directions. Outcomes included degrees of motion, tensile forces experienced in the CPPF device, and stresses in surrounding cortical bone. RESULTS: At maximum loading, laminectomy alone demonstrated an 1° increase in flexion range of motion from 6.35° to 7.39°. Laminectomy with pedicle screw fixation and CPPF device fixation both reduced spinal segmental motion to ≤1° at maximum loading in all ranges of motion, including flexion (0.94° and 1.09°), extension (-0.85°and -1.08°), lateral bending (-0.56° and -0.96°), and torsion (0.63°and 0.91°), respectively. There was no significant difference in segmental stability between pedicle screw fixation and CPPF device fixation during maximum loading with a difference of ≤0.4° in any range of motion. Tensile forces in the CPPF device remained ≤51% the ultimate load to failure (487N) and stress in surrounding cortical bone remained ≤84% the ultimate stress of cortical bone (125.4 MPa) during maximum loading. CONCLUSION: CPFF fixation demonstrated similar segmental stability to traditional pedicle screw fixation while tensile forces and stress in surrounding cortical bone remained below the load to failure.

Finite element analysis and biomechanical study of "sandwich" fixation in the treatment of elderly proximal humerus fractures.

Proximal humerus fractures (PHFs) are common in the elderly and usually involve defects in the medial column.The current standard for medial column reconstruction is a lateral locking plate (LLP) in combination with either an intramedullary fibula support or an autogenous fibula graft. However, autogenous fibula graft can lead to additional trauma for patients and allogeneic fibular graft can increase patients' economic burden and pose risks of infection and disease transmission. The primary objective of this study was to introduce and assess a novel "Sandwich" fixation technique and compare its biomechanical properties to the traditional fixation methods for PHFs. In this study, we established finite element models of two different internal fixation methods: LLP-intramedullary reconstruction plate with bone cement (LLP-IRPBC) and LLP-intramedullary fibula segment (LLP-IFS). The biomechanical properties of the two fixation methods were evaluated by applying axial, adduction, abduction, torsional loads and screw extraction tests to the models. These FEA results were subsequently validated through a series of biomechanical experiments. Under various loading conditions such as axial, adduction, abduction, and rotation, the LLP-IRPBC group consistently demonstrated higher structural stiffness and less displacement compared to the LLP-IFS group, regardless of whether the bone was in a normal (Nor) or osteoporotic (Ost) state. Under axial, abduction and torsional loads, the maximum stress on LLPs of LLP-IRPBC group was lower than that of LLP-IFS group, while under adduction load, the maximum stress on LLPs of LLP-IRPBC group was higher than that of LLP-IFS group under Ost condition, and almost the same under Nor condition. The screw-pulling force in the LLP-IRPBC group was 1.85 times greater than that of the LLP-IFS group in Nor conditions and 1.36 times greater in Ost conditions. Importantly, the results of the biomechanical experiments closely mirrored those obtained through FEA, confirming the accuracy and reliability of FEA. The novel "Sandwich" fixation technique appears to offer stable medial support and rotational stability while significantly enhancing the strength of the fixation screws. This innovative approach represents a promising strategy for clinical treatment of PHFs.

Uncharted Territories: Dynamic Hip Screw Migration Into the Pelvis Requiring Laparotomy.

Hip fractures are common in patients with poor bone quality and are seen to affect the elderly and frail population. We report a case of implant failure after fixing an unstable intertrochanteric fracture with a dynamic hip screw (DHS). The patient presented with a DHS that had migrated into the pelvis approximately six months after surgery. Plain radiographs showed migration of the DHS through the acetabulum and into the pelvis. Migration of DHS into the pelvis is an extremely rare complication and has only been reported a few times. A 71-year-old man presented with a fall and confusion. The patient reported having a fall but could not recall the exact events. Past medical history included Alzheimer's dementia, osteoporosis, left total hip replacement, right DHS, peripheral neuropathy, and recurrent falls. He had undergone reduction and fixation of a right intertrochanteric fracture with DHS implant via direct lateral approach six months before hospital admission. On examination, he had right-sided hip pain and was unable to straighten leg raise. His abdomen was soft and non-tender, with no distension or palpable masses. Neurovascular status was normal, and no signs of infection were detected. On the anteroposterior radiograph, the implant seemed to have migrated through the acetabulum and into the abdomen. A CT of the abdomen and pelvis was performed to identify any visceral injuries (negative) and for surgical planning. The patient underwent a midline laparotomy to remove the implant. Although the exact reason for the implant failure is unknown, the migration of an unbroken hip screw into the abdomen and pelvis requiring laparotomy has not been reported in literature.

Comparison of the Effects of Posterior Cervical Fixation or Posterior Cervical Fixation Extending to the Upper Thoracic Region on Cervical Sagittal Alignment.

OBJECTIVE: For degenerative diseases accompanied by cervical malalignment, the starting and ending points of fixation for better cervical sagittal alignment and clinical results are not as clear as the thoracolumbar region. In this study we aimed to compare the effects of posterior subaxial cervical fixation (PSCF), posterior cervical fixation extending to the upper thoracic region and posterior upper cervical fixation extending to the upper thoracic region on cervical sagittal alignment. METHODS: Sixty-three patients who underwent posterior cervical and cervical-up thoracic fixation were retrospectively analyzed in a comparative study. The procedures that we performed from May 2019 to March 2022 on these 63 patients were: (1) C3-C6 group-posterior subaxial cervical fixation; (2) Subaxial-T2 group-posterior subaxial cervicothoracic fixation (PSCTF); (3) C2-T2 upper thoracic posterior fixation group. The C3-C6 group had 27 patients, Subaxial-T2 group had 24, and C2-T2 group had 12. We determined the minimum follow-up period as 12 months. C0-2, C2-7 lordosis angle, sagittal vertical axis (SVA), C2 slope, C7 slope, T1 slope, cervical slope, neck slope, and thoracic inlet angle (TIA) measurements were made in three patient groups. Comparatively, cervical sagittal alignment was evaluated. RESULT: In the C2-T2 group, a significant increase in C2-C7 lordosis, decrease in C2 slope, and increase in TS-CL were observed. Significant C2-C7 lordosis decrease, C2 slope increase, and TS-CL decrease were observed in the C3-C6 group. A significant increase in C2-C7 lordosis and a decrease in C2 slope were observed in the subaxial-T2 group. No significant change was observed in the TS-CL angle. CONCLUSION: In cervical degenerative disorders accompanied by cervical malalignment, we recommend the C2-T2 fixation method, which provides the desired C2-C7 lordosis, SVA within the normal range, and the best Neck Disability Index results.

Selection of Interferential Screw for Fixation of Graft in Tibial Tunnel during Anterior Cruciate Ligament Reconstruction by Novel Probe Test.

Introduction: Anterior cruciate ligament (ACL) reconstruction is a common orthopedic procedure, employing various grafts such as the hamstring tendon, bone-patellar bone, and quadriceps tendon. Fixation methods include suspensory loop with button, interferential screw, and cortical fixation. The optimal screw diameter for tibial tunnel fixation remains undefined, with choices ranging from 1mm smaller to 1-2 mm larger than the tunnel diameter. Screw-related complications such as breakage and thread flattening are concerns. This study was to determine the ideal screw diameter for secure graft fixation in the tibial tunnel during ACL reconstruction. Materials and Methods: A novel arthroscopic probe technique was utilized to assess tibial tunnel bone integrity. Bone quality was categorized into weak, strong, and very strong. Screw size selection, either equal to or 1-2 mm larger than the tunnel diameter, was based on bone quality. Screw lengths varied from 25 mm to 35 mm. Results: The novel technique significantly reduced screw-related complications, from 9.6% (24 out of 248 patients) to 0.5% (l out of 187 patients). The need for additional cortical stabilization decreased from 14.5% (36 out of248 patients) to 1.6% (3 out of 187 patients). Conclusion: The low-cost, efficient 2-min probe test is a secure and effective method for selecting interferential screws in ACL reconstruction, minimizing complications, and additional stabilization needs.

Screw placement through a higher medial portal provides better initial stability in arthroscopic ACL tibial avulsion fracture fixation: a finite element analysis.

OBJECTIVE: The objective of this study was to investigate the initial stability of different screw placements in arthroscopic anterior cruciate ligament (ACL) tibial avulsion fracture fixation. METHODS: A three-dimensional knee model at 90° flexion was utilized to simulate type III ACL tibial avulsion fracture and arthroscopic screw fixation through different portals, namely the central transpatellar tendon portal (CTP), anterolateral portal (ALP), anteromedial portal (AMP), lateral parapatellar portal (LPP), medial parapatellar portal (MPP), lateral suprapatellar portal (LSP), medial suprapatellar portal (MSP). A shear force of 450 N was applied to the finite element models at 30° flexion to simulate the failure condition. The displacement of the bony fragment and the volume of the bone above 25,000 µ-strain (damaged bone volume) were calculated around the screw path. RESULTS: When the screw was implanted through CTP, the displacement of the bony fragment reached the maximum displacement which was 1.10 mm and the maximum damaged bone volume around the screw path was 148.70 mm3. On the other hand, the minimum displacement of the bony fragment was 0.45 mm when the screw was implanted through LSP and MSP. The minimum damaged bone volume was 14.54 mm3 around the screw path when the screw was implanted through MSP. CONCLUSION: Screws implanted through a higher medial portal generated less displacement of the bony fragment and a minimum detrimental strain around the screw path. The findings are clinically relevant as they provide biomechanical evidence on optimizing screw placement in arthroscopic ACL tibial avulsion fracture fixation.

Aqueous Pretreatment of Lignocellulosic Biomass for Binderless Material Production: Influence of Twin-Screw Extrusion Configuration and Liquid-to-Solid Ratio.

This study was carried out to investigate the continuous aqueous pretreatment of sugarcane bagasse (SCB) through twin-screw extrusion for a new integrated full valorization, where the solid residue (extrudate) was used for the production of bio-based materials by thermocompression and the filtrate for the production of high-value-added molecules. Two configurations, with and without a filtration module, were tested and the influence of the SCB composition and structure on the properties of the materials were determined. The impact of the liquid-to-solid (L/S) ratio was studied (0.65-6.00) in relation to the material properties and the biomolecule extraction yield in the filtrate (with the filtration configuration). An L/S ratio of at least 1.25 was required to obtain a liquid filtrate, and increasing the L/S ratio to 2 increased the extraction yield to 11.5 g/kg of the inlet SCB. The extrudate obtained without filtration yielded materials with properties equivalent to those obtained with filtration for L/S ratios of at least 1.25. Since the molecule extraction process was limited, a configuration without filtration would make it possible to reduce water consumption in the process while obtaining high material properties. Under the filtration configuration, an L/S ratio of 2 was the best tradeoff between water consumption, extraction yield, and the material properties, which included 1485 kg/m3 density, 6.2 GPa flexural modulus, 51.2 MPa flexural strength, and a water absorption (WA) and thickness swelling (TS) of 37% and 44%, respectively, after 24 h of water immersion. The aqueous pretreatment by twin-screw extrusion allowed for the overall valorization of SCB, resulting in materials with significantly improved properties compared to those obtained with raw SCB due to fiber deconstruction.

Open Reduction and Internal Fixation with Plate and Screw versus Triplanar External Fixation in the Surgical Treatment of Calcaneal Fractures: A Retrospective Cohort Study.

Background: The treatment of displaced intra-articular calcaneal fractures (DIACF) is debated. This study compares open reduction and internal fixation (ORIF) with minimally invasive osteosynthesis (MIOS). Methods: We conducted a retrospective study on 70 patients with DIACF treated between January 2018 and September 2022, divided into ORIF (n = 50) and MIOS (n = 20) groups. Functional outcomes were assessed using the Maryland Foot Score (MFS) and the Creighton-Nebraska Health Foundation Assessment Scale (CNHFAS). Radiographic outcomes, complication rates, and reintervention rates were evaluated. A chi-square analysis examined the correlation between Sanders classification and treatment choice. Results: The chi-square analysis indicated no significant correlation between the complexity of the fracture and the type of treatment chosen (χ2 = 0.175, p = 0.916). Additionally, the Cochran-Armitage test for trend showed no significant trend in the choice of treatment based on fracture complexity (statistic = 0.048, p = 0.826). A Kaplan-Meier analysis showed a longer time to reintervention for MIOS (p = 0.029). Complication rates were similar, with specific complications varying between groups. Quality-of-life outcomes were comparable. Conclusions: ORIF is preferable for high-demand patients due to better anatomical outcomes, while MIOS suits high-risk patients by reducing reinterventions and complications. Further randomized trials are needed to confirm these findings.

Intramedullary Screw versus Locking Plate Fixation for Traumatic Displaced Proximal Fifth Metatarsal Fractures: A Systematic Review.

Background/Objectives: Intramedullary screw fixation (IMS) and locking plate fixation (LPF) are currently recommended treatments for proximal fifth metatarsal fractures (PFMF). However, treating comminuted or small displaced avulsion PFMF with IMS poses challenges due to complications. A novel alternative fixation method, the locking compression plate for distal ulna hook plate fixation (LPF), has been introduced recently for distal ulna fractures and has shown improved clinical results. This scoping review aims to assess whether LPF yields superior outcomes, such as postoperative AOFAS scores and rate of postoperative complications, compared to IMS in PFMF treatment. Methods: This review included randomized controlled trials (RCTs), prospective cohort studies, retrospective cohort studies, or case series involving patients with PFMF who underwent plate fixation or screw fixation. The primary outcome was the postoperative American Orthopedic Foot and Ankle Society (AOFAS) score. Studies were sourced from databases including PubMed, Embase, and Scopus, with the search conducted up to February 2024. The Systematic Review protocol was registered in the CRD PROSPERO database (CRD42024532593). Results: Ten studies were included, comprising 3 cohort studies, 1 case-control study, and 6 case series, with a total of 309 patients (158 with LPF and 142 with IMS). The postoperative AOFAS scores showed no significant difference between LPF and IMS in treating PFMF. However, LPF demonstrated efficient surgical procedures and enhanced functional outcomes. Complications were minimal in both groups, with no significant difference in the rate of postoperative complications. Conclusions: Although there was no significant difference in AOFAS scores between LPF and IMS, LPF demonstrated efficient surgical procedures and enhanced functional outcomes, making it a reasonable alternative method for PFMF. Effective shared decision-making (SDM) with patients becomes paramount in choosing the optimal surgical approach. In the surgical landscape, thoughtful deliberation, patient engagement, and adherence to biomechanical principles are crucial for achieving successful outcomes in the treatment of PFMF.