STABILITY OF MEDIALLY AND LATERALLY MALPOSITIONED SCREWS: A BIOMECHANICAL STUDY ON CADAVERS.

BACKGROUND CONTEXT: Pedicle screw instrumentation is widely used in spine surgery. Axial screw misplacement is a common complication. In addition to the recognized neurovascular risks associated with screw misplacement, the biomechanical stability of misplaced screws remains a subject of debate. PURPOSE: The present study investigates whether screw misplacement in the lumbar spine reduces mechanical screw hold. STUDY DESIGN/SETTING: Cadaveric biomechanical study METHODS: Pedicle screw (mis)placement was planned for 12 fresh frozen cadaveric spines between the T12 and the L5 levels. The screws were then implanted into the vertebrae with the help of 3D-printed template guides. Pre- and post-instrumentation computed tomography (CT) scans were acquired for instrumentation planning and quantification of the misplacement. The instrumented vertebrae were potted into CT transparent boxes using Polymethyl methacrylate and mounted on a standardized biomechanical setup for pull-out (PO) testing with uniaxial tensile load. RESULTS: The bone density of all the specimens as per HU was comparable. The predicted pull-out force (POF) for screws medially misplaced by 2mm, 4mm, and 6mm was respectively 985 N (SD 474), 968 N (SD 476) and 822 N (SD 478). For screws laterally misplaced by 2mm, 4mm, and 6mm the POF was respectively 605 N (SD 473), 411 N (SD 475), and 334 N (SD 477). Screws that did not perforate the pedicle (control) resisted pull-out forces of 837 N (SD 471). CONCLUSIONS: Medial misplacement is associated with increased axial screw hold against static loads compared to correctly placed screws and laterally placed screws. CLINICAL SIGNIFICANCE: In clinical settings, the reinsertion of medially misplaced screws should primarily aim to prevent neurological complications while the reinsertion of lateral misplaced screws should aim to prevent screw loosening.

Neuro Navigation Versus Conventional Spinal Techniques in Analyzing Nerve Injury and Anatomical Accuracy: A Systematic Review.

Neuronavigation, a computer-assisted surgical technique, enhances the accuracy of spinal surgery by using medical imaging to guide the surgeon's instruments. This method mitigates the serious complications of screw misplacement, such as dural tears, nerve damage, vascular injuries, and internal organ damage, by integrating pre-operative imaging data with real-time intraoperative sensor readings. Because of this integration, it is possible to visualize the spine in three dimensions, guaranteeing accurate instrument placement and greatly lowering the risk of complications. Despite its growing popularity, the benefits of neuronavigation in spinal instrumentation are debated. While some studies report improved accuracy in pedicle screw placement, others find no significant difference compared to conventional freehand techniques. Further research is required to determine the long-term benefits of neuronavigation, including its impact on patient outcomes, like reduced pain and improved function. This systematic review will evaluate the evidence on the risks and benefits of neuronavigation in spinal instrumentation surgery, compared to conventional techniques.

Comparative assessment of the stability of buccal shelf mini-screws with and without pre-drilling- a split-mouth, randomized controlled trial.

OBJECTIVES: To examine and compare the stability of buccal shelf mini-screws using self-drilling and pre-drilling implant placement techniques. METHODOLOGY: It was a split-mouth, randomized controlled trial comprising of 7 patients, each receiving two buccal shelf bone screws. The screws were placed using a self-drilling protocol in one quadrant and a pre-drilling protocol in the opposing quadrant decided via coin toss randomization. Stability was examined at the time of placement and 1,2, 3 and 4 months thereafter, using the Resonance Frequency Analysis method with the Osstell Beacon TM device. The Implant Stability Quotient (ISQ) obtained was then compared and assessed between both quadrants. Friedman's Two-Way Analysis of Variance and the Wilcoxon signed rank test were utilized for the intergroup comparison. A statistically significant result was defined as one with a p-value of less than 0.05. RESULTS: A statistically significant difference between the mean ISQ reading in the pre-drilling and self-drilling group was observed, indicating higher stability of bone screws placed with the pre-drilling protocol. The primary stability of the buccal shelf screws decreased after placement, but the secondary stability remained stable. CONCLUSION: Buccal shelf bone screws placed with a pre-drilling protocol depicted greater primary and secondary stability as compared to the self-drilling protocol, as depicted by the ISQ readings obtained. Resonance Frequency Analysis can be used as a valuable tool to assess the stability of buccal shelf bone screws. CLINICAL RELEVANCE: The use of buccal shelf screws has increased tremendously over the past few years due to their myriad applications and have now become an essential part of an orthodontist's armamentarium. It is therefore essential for clinicians to be well-informed about all aspects of their use including insertion techniques. The results of this trial indicate that the pre-drilling protocol provides better stability and therefore treatment outcomes.

Arthroscopic Reconstruction of Injured Anterior Cruciate Ligament Using Peroneus Longus Graft With Fixed Loop Endobutton - A Prospective Study.

Introduction: ACL injuries are more common amongst active young people where RTA and sports injuries predominate as the most common methods of injury ACL reconstruction with peroneus longus graft method have been used more frequently nowadays. The advantages of peroneus longus graft are, Adequate graft length of minimum of 25 to 30 cm. Adequate thickness of minimum 8.5 to 9mm,Less incidence of graft thinning, Lesser hamstring and quadriceps weakness, Minimal donor site morbidity. Minimal restriction of ankle movements. Materials and Methods: A prospective study of 25 patients with injured anterior cruciate ligament without meniscal injury within the age group of 18-55 years managed with arthroscopic reconstruction of anterior cruciate ligament with peroneus longus graft and fixed loop endobutton at femoral side and interference screw at tibial side. Functional outcome was assessed using clinical examination, International Knee Documentation committee and Lysholm knee scoring scale, FADI score (foot and ankle disability index score). Patients were followed up at 2, 4, 8, 12weeks and 6, 8 months post-operatively. Results: This study consists of 25 cases of Anterior Cruciate Ligament injury. ACL rupture was common in second and third decade of life. In our study, 18(63.34%) were sports related injuries, 5(26.66%) were due to road traffic accidents and 2(10%) were atraumatic degenerations. 22(80%) showed excellent results and 3(20%) showed good results. Conclusions: Arthroscopic ACL reconstruction using peroneus longus graft and Fixed-loop Endobutton and interference screws provided excellent post-operative clinical outcome in terms of knee stability, subjective knee and ankle function and range of movements of the knee and ankle in our study.

Surgical Treatment of Non-Displaced Subcapital Hip Fracture: Femoral Neck System vs. Cannulated Screws. Comparative Study. / Tratamiento quirúrgico de fractura subcapital de cadera no desplazada: Femoral Neck System vs Tornillos canulados. Estudio Comparativo.

OBJECTIVE: The objective of this study is to compare the outcomes of using the Femoral Neck System (FNS) (DePuy Synthes®) versus the use of cannulated screws (CS) in the surgical treatment of non-displaced subcapital hip fractures. MATERIALS AND METHODS: A retrospective cohort study was conducted on non-displaced subcapital hip fractures treated with CS or FNS between 2020 and 2023, with a minimum follow-up of one year. A total of 28 patients were included, 14 treated with CS and 14 with FNS. Demographic, radiological, clinical, and functional variables were analyzed. RESULTS: In the CS group, 64% were male, with a mean age of 66.5 years (SD 14.9) and an average follow-up of 22 months (range, 12-36 months). In the FNS group, 57% were male, with a median age of 60.8 years (SD 13.78) and an average follow-up of 16 months (range, 12-24 months). Regarding functional outcomes, no significant differences were found between FNS and CS in the Harris scale: 94.21 ± 11.55 for FNS and 96.50 ± 6.9 for CS (p=0.618). The total postoperative complications (FNS/CS) were 7.1% versus 43%, and implant failure with conversion to total hip replacement was 0% versus 43%, both significantly higher in the CS group (p=0.047; p=0.016, respectively). The FNS also presented a lower rate of avascular necrosis (0% versus 11.1%, p=0.391) and nonunion (0% versus 20%, p=0.163), although these differences did not reach statistical significance. CONCLUSIONS: Although both treatment methods, cannulated screws and the Femoral Neck System (FNS), showed similar short-term functional outcomes in the management of undisplaced subcapital femoral fractures, the FNS demonstrated a significantly lower rate of complications and reoperations. These results suggest that the FNS could be considered a safer and more effective option compared to cannulated screws.

Advancing the design of interspinous fixation devices for improved biomechanical performance: dual vs. single-locking set screw mechanisms and symmetrical vs. asymmetrical plate designs.

Background: Interspinous devices were introduced in the field of spine surgery as an alternative to traditional pedicle screw fixation in selected patients for treatment of spinal stenosis and fixation. These devices designs have evolved from non-fixated extension blocks to sophisticated interspinous fixation devices (IFDs). There is an absence of literature comparing the biomechanical fixation strength of different IFD plate designs and the role of set screw locking systems. The aim of this study was to evaluate fixation strengths by bench testing static disassembly and pullout strength of two dissimilar IFD designs and locking mechanisms. We hypothesized that the InSpan (InSpan LLC, Burlington, MA, USA) dual-locking symmetrically IFD plate designed will have stronger fixation than the Aspen (ZimVie, Parsippany, NJ, USA) single-locking asymmetric IFD plate design. Methods: We conducted two biomechanical bench tests to evaluate the load to failure locking characteristics of symmetrical InSpan and asymmetrical Aspen IFD designs. Static pullout testing involved locking each IFD to the stainless steel and 40 pcf cellular polyurethane foam and measuring pullout load and displacement six times. Seven InSpan and two Aspen IFDs (including the "used" IFDs from the pullout testing) underwent static disassembly tests using a pair of disassembly fixtures positioned between the IFD plates to measure disassembly force and displacement. All tests were performed under ambient conditions using an INSTRON 8874 Bi-Axial Tabletop Servohydraulic Dynamic Testing System (INSTRON, Norwood, MA, USA), and data was collected at a 0.2 mm/s displacement control rate until the test was stopped when there was a drop in the continuously increasing force against resistance (gross failure). Results: The InSpan IFD experienced 94.81% higher resistance to pullout compared to the Aspen IFD in static pullout testing (P<0.05), owing to its notably larger footprint area of 69.8%. Gross failure for both IFD implant designs occurred at the foam block-block interface. In static disassembly testing, pristine InSpan required 60.7% higher force over pristine Aspen and 401.3% for "used" IFDs. Gross failure was characterized by the gradual distraction of the plates and material removal at the set screw contact points. Implant failure at the block-implant interface emphasized the pivotal role of teeth design and the contact surface area of the plates in ensuring stability. Conclusions: The dual-locking symmetrical InSpan IFD outperformed single-locking asymmetric Aspen IFD in both static disassembly and pullout bench tests. This highlights the benefits of InSpan's improved design and its potential for enhanced long-term stability in spinal fixation applications.

A comparative cadaveric biomechanical study of bilateral FacetFuse® transfacet pedicle screws versus bilateral or unilateral pedicle screw-rod construct.

Background: Achieving optimal immediate stability is crucial in lumbar fusion surgeries. Traditionally, four pedicle screws have been utilized to provide posterior stability at the L5-S1 level. However, the use of bilateral transfacet pedicle screws (TFPS) as an alternative construct has shown promising results in terms of biomechanical stability. This research paper investigates the biomechanical stability of TFPS with a lag design in comparison to equivalent-sized unilateral or bilateral fully threaded pedicle screw-rod (PSR) constructs at the L5-S1 disc level. The study assesses the immediate stability achieved by these constructs which have clinical implications in achieving lumbar segment fusion. We hypothesized that bilateral TFPS will yield immediate lumbar fixation that is comparable to unilateral or bilateral PSR constructs. Methods: Cadaveric biomechanical testing was conducted in vitro to evaluate the stability of posterior fixation using bilateral TFPS (FacetFuse®, LESSpine, Burlington, MA, USA), bilateral and unilateral PSR (PedFuse Return, LESSpine, Burlington, MA, USA) constructs measuring 5.0 mm × 40 mm. A comprehensive analysis of range of motion (ROM) and stability under various loading conditions was performed to a maximum of 7.5 Nm. The constructs were assessed for their ability to provide immediate stability at the L5-S1 disc level. Results: Fourteen specimens were analyzed with an average age of 53.14±10.99 years and comparable bone mineral density. TFPS demonstrated a reduced ROM that was notably lower than that of unilateral PSR in all loading modes and was comparable to bilateral PSR, especially in extension and axial rotation (AR). The unilateral and bilateral PSR groups differed notably in lateral bending (LB) and AR. Conclusions: Bilateral TFPS demonstrated superior immediate stability than unilateral PSR and was an equivalent substitute to bilateral PSR constructs at the L5-S1 disc level. Further clinical investigations are necessary to validate these results and ascertain the long-term outcomes and advantages associated with the use of bilateral TFPS as an alternative construct. Our findings showed that bilateral TFPS could potentially reduce the number of required pedicle screws while achieving comparable stability in lumbar fusion procedures.

Real-world clinical accuracy of long cortical bone trajectory screw placement using a patient-specific template guide.

Background: Cortical bone trajectory (CBT) screws can be very reliable anchors if inserted precisely anterior to the vertebral body; however, their trajectory is narrow, and malpositioning of the screw is not rare, especially for surgeons who are not familiar with the CBT screw. Patient-specific template guides are a solution to this problem; however, their accuracy and usefulness in clinical settings remain unclear. The aim of the present study was to evaluate the accuracy of long CBT placement using a patient-specific screw-guide system. Methods: This research involved a retrospective clinical evaluation of patients who had been enrolled prospectively. One hundred consecutive patients who underwent posterior lumbar spinal fusion using the guide system performed by three experienced spine surgeons were included. Initially, the placement of the CBT screws was mapped out in three dimensions utilizing simulation software. Prior to the surgery, a specific screw guide was designed for each vertebra. Using these guides, a total of 412 screws were placed. To assess any perforation of the pedicle and to compare the discrepancies between the intended and the actual positions of the screws, postoperative computed tomography (CT) scans were utilized. Results: Overall, 382 screws (92.7%) were fully inside the pedicle (L2-5) and there was no incidence of neurovascular injuries. The mean depth of the screw in the vertebral body (% depth) was 60.9%±8.1% and the mean % depth deviation between planned screws and actual screw was 9.6%±7.1% in total. In all vertebrae, the mean % depth was approximately 10% smaller for the actual screws than the planned screws. The mean sagittal and transverse angular deviations between the planned screws and actual screws were 2.30±1.87° and 1.89±1.26°, respectively. Overall, deviation in the sagittal angle tended to be cranial. Conclusions: We demonstrated that a patient-specific screw guide is useful for supporting precise long CBT screw insertion into the lumbar spine in a clinical setting. This patient-specific template guide could be a potential solution to accurately insert long CBT screws and reduce complications, even for surgeons who are not experienced in the CBT technique.

Long-term outcomes following closed reduction and internal fixation of femoral neck fractures with cannulated screws in patients under 65 years.

Background: The long-term studies for femoral neck fractures (FNFs) in young patients treated with closed reduction and internal fixation (CRIF) are limited. This study aimed to evaluate the long-term outcomes of a group of young patients (<65 years) with FNFs treated with CRIF at our department during the last decade. We estimated treatment failure rates and identified risk factors for poor outcomes. Methods: This retrospective cohort study included patients under 65 with a unilateral FNF treated with CRIF using partially threaded cannulated screws (CSs) between 2011 and 2021. During the latest follow-up visit, we recorded the patients' complications, re-admissions, reoperations, functional outcomes, and quality of life scores. Results: We included 52 patients with a mean age of 53.04 years and a mean follow-up of 5.3 (range: 1.3-11) years. No non-union was recorded. Nine patients (17.3 %) underwent total hip arthroplasty (THA) due to femoral head avascular necrosis (AVN) at an average of 1.68 years following the index operation (THA group). The mean age (p =0.96), trauma type (p =0.290), sex prevalence (p =0.989), Garden classification (p =0.187), CSs number (p =0.751), and comorbidities (p =0.516) were comparable between THA and non-THA groups. Time from trauma to index surgery was significantly shorter for the THA than the non-THA group (p =0.03). Conclusions: During a mid-to-long follow-up, 17.3 % of patients under 65 years who were treated with CRIF and CSs for FNFs developed AVN. Age, trauma type, comorbidities, time from trauma to treatment, and the number of screws did not affect the outcomes. HIPPOKRATIA 2024, 28 (1):29-34.

Radial Head Fracture (Mason Type 4) Fixation With Headless Compression Screws: The "Tripod Technique".

Radial head fractures are fairly common fractures in the general population accounting for up to 30% of elbow fractures. The management of these fractures is controversial, specially in the higher grade of fractures. The current case report presents a middle-aged male patient with a fracture dislocation of the radial head in the dominant hand. After undergoing adequate investigations, the fracture was classified and managed with headless compression screws using the tripod technique. The management of the patient, preoperative planning, and the complications faced are mentioned in the current report. The patient on follow-up shows a good range of motion and an improved Mayo elbow score. Thus, stating good results can be obtained in Mason type 4 fractures using osteosynthesis with headless compression screws.

Comparison of Different Implant Systems by Stress and Resistance of Prosthetic Screws: An Original Research.

Introduction: For the best possible clinical results, dental implant systems must have their biomechanical characteristics thoroughly evaluated. These systems are essential to restorative dentistry. The purpose of this study was to analyze the resistance and stress distribution of prosthetic screws across five distinct implant systems. Methods: The stress distribution on prosthesis screws was evaluated, and loading conditions were simulated using finite element analysis (FEA). To assess the screws' resistance to torque forces, mechanical testing was done. Findings: Among the implant systems, there were notable differences in torque resistance and stress distribution. System A had the least amount of stress and the most torque resistance, whereas System E displayed the most stress and the least torque resistance. Conclusion: The results emphasize the significance of taking biomechanical characteristics into account when choosing implant systems for clinical usage, which has ramifications for patient care and treatment planning. Additional investigation concentrating on thorough clinical assessments is necessary to confirm these results and enhance treatment plans.

Interdisciplinary Management of Bilateral Palatally Impacted Canines With Mini-Screws as Temporary Anchorage Devices: A Case Report.

Dealing with impacted maxillary teeth can be quite challenging for dental professionals. The advantage of using temporary anchorage devices (TADs) in the treatment of bilateral palatally impacted canines is the ability to exert more controlled and directed forces on the impacted tooth. Utilizing TADs might result in enhanced outcomes, including better tooth positioning within the dental arch and reduced risk of complications, such as root resorption. This article highlights the importance of diagnosis, adequate treatment planning for the eruption of impacted canines, and also managing tooth-arch size discrepancy to achieve a balanced occlusion and dental aesthetic. This is a case report on the interdisciplinary management of bilateral palatally impacted canines using mini-screws as TADs.

Comparative analysis of the femoral neck system (FNS) vs. cannulated cancellous screws (CCS) in the treatment of Middle-aged and elderly patients with femoral neck fractures: clinical outcomes and biomechanical insights.

PURPOSE: This study aimed to compare the clinical outcomes and differences in biomechanical characteristics between the femoral neck system (FNS) and cannulated cancellous screws (CCSs) in the treatment of femoral neck fractures. METHODS: This study retrospectively analysed a cohort of 38 registered cases of femoral neck fractures treated surgically with either the FNS (n = 17) or CCSs (n = 21) between January 2020 and December 2023. Indicators such as fluoroscopy frequency, length of hospital stay, and fracture healing time were compared between the two groups. Functional status was evaluated via the Harris hip score (HHS) and visual analogue scale (VAS), whereas prognosis was assessed based on changes in the neck shaft angle and femoral neck shortening. Additionally, six sets of femoral neck fracture models were developed based on Pauwels angles of 30°, 40°, 50°, 60°, 70°, and 80°. Two experimental groups, FNS and CCS, were established, and a joint reaction force of 1800 N was applied to the proximal femur. The displacement, stress, and stiffness of the components of interest in the different models were tested and compared. RESULTS: The distributions of all the baseline characteristics were similar between the two groups (p > 0.05). The FNS group presented significantly shorter fluoroscopy frequency, length of hospital stay, and fracture healing time (p < 0.05). Harris and VAS scores were higher in the FNS group than in the CCS group (p < 0.05). Postoperative changes in the neck shaft angle and femoral neck shortening were significantly lower in the FNS group than in the CCS group (p < 0.05). The results of the finite element analysis indicated that the maximum stress on the femoral head and varus angle were generally lower in the FNS group than in the CCS group and that the maximum displacement of the femoral head and FNS was generally lower in the FNS group than in the CCS group. However, the superiority of FNS over CCS decreased with increasing Pauwels angle. Additionally, the effectiveness of FNS in limiting displacement of the femoral neck upper wall was not as favourable as that of CCS. CONCLUSIONS: The treatment of femoral neck fractures with FNS is superior and contributes to improved hip joint function. Biomechanical research has confirmed its structural stability and advantages in resisting femoral head varus. However, challenges to its fixation efficacy persist, particularly at higher Pauwels angles.

Minimally invasive robot-assisted direct pars repair: illustrative cases.

BACKGROUND: Robot-assisted techniques are increasingly integrated into the field of spine surgery, with the potential benefits of increased accuracy and reduced radiation exposure. The objective of this study was to describe the technique of minimally invasive robot-assisted direct pars repair with 2 case illustrations. OBSERVATIONS: An 18-year-old male and a 42-year-old male, both with bilateral L5 spondylolysis, underwent successful minimally invasive L5 direct pars repairs with robotic assistance after conservative measures failed, and their cases are presented herein. LESSONS: A robot-assisted direct pars repair is a safe and effective technique for treating bilateral lumbar spondylolysis. The integration of robot-assisted techniques in spine surgery has the potential to improve outcomes, decrease surgical time, and reduce the amount of radiation exposure to operating room staff. https://thejns.org/doi/10.3171/CASE2415.

Improving C1 Pedicle Screw Placement for Atlantoaxial Instability with Ultrasonic Bone Burr Assistance.

OBJECTIVE: This study aims to evaluate the safety and efficacy of the ultrasonic bone burr (UBB) in facilitating C1 pedicle screw placement for atlantoaxial instability treatment, compared to the conventional high-speed drill (HSD) technique. METHODS: A retrospective analysis was conducted on patients undergoing posterior screw-rod fixation for atlantoaxial instability between December 2017 and July 2023. The patients were divided into 2 groups based on the tools used for screw placement: UBB and HSD. Data on surgical duration, estimated blood loss, spinal cord and arterial injury incidence, screw placement accuracy, neurological status measured by the Japanese Orthopedic Association score, and fusion rates were collected and analyzed. RESULTS: Thirteen patients received C1 pedicle screw placement via UBB facilitation, while 8 were treated using the HSD approach. The UBB group showed a significant reduction in blood loss and operation time compared to the HSD group (P = 0.002 and P < 0.001, respectively). No spinal cord or arterial injuries occurred in either group. Optimal screw placement was confirmed in all UBB cases versus 87.5% in the HSD group (P = 0.139). Both groups demonstrated significant improvements in Japanese Orthopedic Association scores with no intergroup difference. The fusion rate was 100% in the UBB group and 87.5% in the HSD group, not statistically different (P = 0.381). CONCLUSIONS: UBB is a viable alternative for C1 pedicle screw placement, associated with reduced blood loss and shorter operation time, while achieving comparable clinical outcomes to the conventional HSD method. Nevertheless, further research with a larger sample size is needed.

Accuracy of Orthodontic Anchor Screw Placement Using a 3D-Printed Surgical Guide.

Background Although radiographs and computed tomography (CT) images are reviewed before temporary anchorage device (TAD) implantation, implantation of TADs exactly as planned is difficult. This study aimed to evaluate the accuracy of TAD implantation using an original surgical guide fabricated using cone-beam CT data and computer-aided design software. Methodology The study participants included six experienced orthodontists who had implanted ≥20 TADs, and six inexperienced orthodontists who had never implanted a TAD. Maxillary dental typodont models with radiopaque tooth crowns and roots were used. A total of four TADs were implanted on the buccal sides: between the second bicuspid and first molars and between the first and second molars bilaterally. The accuracy of TAD implantation was examined in two groups: in 12 dental typodont models, TAD implantation was performed using a surgical guide (guide group), and in 12 dental typodont models, TAD implantation was performed without a surgical guide (freehand group). All dental typodont models implanted a total of 96 TADs. The TAD position was evaluated using the CT coordinate system and 3D image measurement software. Using the long axis of the TAD as a reference, the distance between the coronal and apical ends of the implanted TAD and those of the planned TAD, i.e., the ideal implantation position, was measured in both groups along the x, y, and z axes. The medians of the values were compared between the groups. Additionally, the presence of root contact was compared between the experienced and inexperienced orthodontists. Results On the x-axis, the linear deviations (median) of the coronal and apical ends of the TAD in the freehand group were 1.06 mm and 1.36 mm, respectively. In contrast, in the guide group, the deviations were 0.65 mm and 0.90 mm, respectively, and the difference was statistically significant (p = 0.002 and p = 0.005, respectively). On the y-axis, the deviations in the freehand group were 1.13 mm and 1.08 mm, respectively. In contrast, the deviations in the guide group were 0.71 mm and 0.79 mm, respectively, and only the coronal deviations were significantly different between the groups (p = 0.006). On the z-axis, the deviations in the freehand group were 1.44 mm and 1.86 mm, respectively. In contrast, the deviations in the guide group were 0.75 mm and 1.16 mm, respectively, and the difference was statistically significant (p = 0.006 and p = 0.002, respectively). Conclusions The use of a surgical guide allowed for more accurate TAD implantation. Additionally, TAD implantation using a guide prevented root damage.

The Legacy of Harrington's Rod and the Evolution of Long-Segment Constructs in Spine Surgery.

This paper delves into the historical evolution of spinal surgery, focusing on the pivotal role of the Harrington rod in treating spinal deformities. Introduced in 1955, the Harrington rod marked a significant breakthrough in neurosurgery, especially for scoliosis treatment, by offering a novel approach to spinal stabilization. Through a retrospective analysis, this study examines the development and impact of the Harrington rod, highlighting Dr. Paul Harrington's contributions to spinal surgery. His innovative technique revolutionized the management of spinal deformities, laying the groundwork for future advancements in spinal instrumentation. Despite initial skepticism, Harrington's methods gained acceptance, significantly influencing neurosurgical practices and patient outcomes. This study also explores subsequent advancements that built on Harrington's work, including the transition to long-segment spine constructs and the introduction of segmental pedicle screws, which allowed for more precise deformity correction. Reflecting on Harrington's legacy, this paper acknowledges the continuous evolution of spinal surgery, driven by the interplay between clinical challenges and technological innovations. Harrington's pioneering spirit exemplifies the ongoing pursuit of better surgical outcomes, underscoring the importance of innovation in the field of neurosurgery.

Comparison of treatment of volar Barton's fracture with T plate using distal end screws and without distal end screws.

Objective: To compare the functional and radiological outcomes of treatment of volar Barton's fractures using T plate with and without distal end screws. Methods: This randomized control trial was conducted at the department of Orthopedics, Mayo Hospital, Lahore, Pakistan from December 2021 to May 2022. Total 60 patients (30 in each group) were randomly allocated to either group A (T-Plate with distal end screws) or B (T-Plate without distal end screws). Patients were followed up on day-0, day-14, day-28 and day-90. Assessments of patients were done by Green O'Brien Score for pain, Modified Warden Score for callus formation on radiographs at 12-weeks of follow-up and Stewart Score for displacement of fracture. Results: At 90th day, significant difference was seen in Green O'Brien Score (Excellent score: Group-A: 80% vs. Group-B: 90%, p=0.278) while Stewart scores remained comparable (Excellent Score: Group-A: 93.33% vs. Group-B: 96.67%, p=0.221) between treatment groups. Fracture healing assessed with Modified Warden score for score 4 did not show significant difference between both groups at 90th day. i.e. (Group-A: 96.67% vs. Group-B: 96.67%). However, callus formation assessed with Modified Warden score for score 3 showed significant differences between groups at 90th day. i.e. (Group-A: 53.33% vs. Group-B: 86.67%, p=0.001). Conclusion: Both treatment approaches appear to yield comparable outcomes in terms of clinical assessment, Stewart scores, and fracture healing, with a potential advantage for T-plate without distal end screw in callus formation at the 90th day.Trial registration: IRCT20221231056999N1.

Pre-operative virtual three-dimensional planning for proximal humerus fractures: A proof-of-concept study.

Purpose: To (1) evaluate surgeon agreement on plating features (position and screw length) in virtual 3D planning software, (2) describe outcomes (fracture reduction, plate position, malpositioning of calcar screws and screw lengths) of plate fixations planned with routine pre-operative assessment (2D- and 3D CT imaging) and those planned with dedicated virtual 3D software of the same proximal humerus fracture. Methods: Fourteen proximal humerus fractures were retrospectively reduced and fixed with virtual planning software by eight attending orthopaedic surgeons and compared to the true surgical fixation with post-operative computed tomography (CT) scans. Reduction differences were quantified using CT micromotion analysis. Results: Intraclass correlation for screw lengths was 0.97 (95% CI: 0.96-0.98) and 0.90 (95% CI: 0.79-0.96) for plate position. Mean difference in total fracture rotation of the head between the virtual and conventional group was 22.0°. Plate position in the virtual planning group was 3.2 mm more proximal. There were no differences in inferomedial quadrant calcar screw positioning and, apart from the superior posterior converging screw, no significant differences in screw lengths. Conclusion: Reproducibility on plate position and screw length with virtual planning software is adequate. Apart from fracture reduction, virtual planning yielded similar plate positions, screw malpositioning rates and lengths compared to routine pre-operative assessment.

Osteosynthesis for mandibular reconstruction with fibula free flap: Which type and why? A French national survey.

We explored the most suitable osteosynthesis type for mandibular reconstruction using fibula free flap (FFF) given the lack of robust data available. For this, an anonymous survey was e-mailed to 853 head-and-neck surgeons (France) asking about their practices and criteria guiding their osteosynthesis material and method choices. Questions assessed: (1) the most frequently used osteosynthesis type, (2) the explanatory variables related to surgeon career status/surgical specialty, and (3) justifications for osteosynthesis type (scientific, technical, "misuse"). Multivariate logistic regression was performed to test for associations of explanatory variables with plate type or misuse. Overall, 118 (13.8%) surgeons responded, among which flexible non-locking osteosynthesis was preferred (59%). Career status and surgical specialty were significantly associated with material choice. University professors/senior lecturers (OR 5.96 vs academic clinical associates; p = 0.02), but not ear-nose-throat/reconstructive plastic surgeons (OR 0.22 vs maxillofacial surgeons; p = 0.04), were more likely to opt for rigid locking osteosynthesis. Private practitioners preferred flexible non-locking osteosynthesis (OR = 5.03; p = 0.04). Only 18% of surgeons scientifically justified their choices. We considered misuse among 65% of surgeons and this was significantly associated with irregular practice of FFF surgery (OR 2.28 vs > 10 surgeries/year; p = 0.04). Overall, >50% of surgeons mainly rely on habits without scientific arguments assisting in decision-making.