Lumbar Pedicle Research Articles

Robotic Pedicle Screw Placement with 3D MRI Registration: Moving Towards Radiation Free Robotic Spine Surgery

BACKGROUND CONTEXTPreoperative imaging for lumbar spine surgery often includes magnetic resonance imaging (MRI) for soft tissues and computer tomography (CT) for bony detail. While CT scans expose patients to ionizing radiation, whereas MRI scans do not. Emerging MRI techniques allow CT-like three-dimensional (3D) visualization of bony structures, potentially removing the need for ionizing radiation from CT scans. PURPOSEThis study aims to explore the accuracy of robot-assisted lumbar pedicle screw placement based on preoperative CT-like 3D MRI as the data source for robotic registration. STUDY DESIGNHuman cadaveric study. METHODS: CT-like 3D MRI scans of the lumbar spine were acquired in ten human cadavers. A robotic navigation platform was used to plan and navigate pedicle screw placement based on the CT-like 3D MRI. Postoperative CT scans assessed the accuracy of screw positioning compared to preoperative planning based on the Gertzbein-Robbins scale (GRS) and by direct measurement (mm). RESULTSA total of 100 lumbar pedicle screws were robotically placed in ten cadavers (L1 through L5 bilaterally) based on CT-like 3D MRI. On postoperative CT evaluation, 99.0% of the positioned screws achieved an acceptable grade on the GRS (Grade A: n = 89 or Grade B: n = 10), with 89.0% classified as Grade A and 10.0% as Grade B. Meaning that 89.0% of screws were fully contained within the pedicle (GRS A), and 10% had a minor cortical breach <2mm (GRS B). The median deviation from the planned trajectory was 0.2 mm (axial IQR: 0.1 to 0.5 mm; sagittal: IQR: 0.1 to 0.4 mm), in both axial and sagittal planes. CONCLUSIONThis study showed that image registration of CT-like 3D MRI for robotic-assisted spine surgery is technically feasible and that accurate pedicle screw placement can be achieved without preoperative CT. Each CT-like 3D MRI was successfully registered for robotic navigation. CLINICAL SIGNIFICANCEThe results suggest that CT-like 3D MRI has the potential to be a radiation-free alternative for preoperative planning and navigation in lumbar spine instrumentation procedures.

Expert consensus on the clinical application of cortical bone trajectory for lumbar pedicle screws: results from a modified Delphi study.

A modified Delphi study. This study sought to establish expert consensus on the use of cortical bone trajectory (CBT) for lumbar pedicle screws. The CBT technique is widely used in the treatment of various degenerative lumbar diseases because it reduces surgical time, soft tissue exposure, and blood loss; improves biomechanical stability; and allows for faster patient recovery. However, as an emerging surgical technique, CBT remains controversial in terms of preoperative evaluation methods, key surgical techniques, complication prevention and treatment, postoperative follow-up, and other aspects, resulting in unclear indications and contraindications for some doctors and posing great challenges to the steady promotion of this technique. From May 2021 to August 2021, panelists were chosen to collect expert feedback using the modified Delphi method, and 74 spine surgeons from across China agreed to participate. Four rounds were conducted: one in-person meeting and three subsequent survey rounds. Each question received at least 70.0% agreement, indicating a consensus. The grade A, B, and C recommendation were defined as having ≥90.0%, 80.0%-89.9%, and 70.0%-79.9% agreement on each question, respectively. The panelist group consisted of 74 experts, and 72, 70, and 69 questionnaires were collected in three rounds, respectively. In total, 24 questions with 59 options reached consensus after the Delphi rounds, including indications (adjacent vertebral diseases after lumbar internal fixation) and contraindications (previous surgery or bone destructive diseases lead to the destruction or absence of bone in the lamina or isthmus); advantages (intraoperative traction of paravertebral soft tissue is small) and disadvantages (not three-column fixation.); preoperative evaluation; complications; and postoperative follow-up evaluation, of CBT. The modified Delphi method achieved expert consensus on the clinical use of CBT for lumbar pedicle screws. This consensus document establishes clear guidelines for indications, contraindications, surgical techniques, and postoperative management, thereby enhancing clinical decision-making and promoting the safe and effective use of CBT. While the initial study focused on Chinese surgeons, future research will seek to validate and expand these findings from a broader international perspective.

Practice Pattern Variations in the Use of Neuromonitoring, Image Guidance, and Robotics for Lumbar Pedicle Screw Placement Based on a Nationwide Neurosurgery Survey

Lumbar pedicle screw placement surgery involves various assistive technologies, including fluoroscopic, stereotactic, or robotic navigation and intraoperative neuromonitoring (IONM). We aimed to discern neurosurgeons' preferences for screw placement techniques and IONM utility, while also considering the influence of experience. A survey was distributed to members of the Congress of Neurological Surgeons using REDCap software, collecting demographic data and querying preferred techniques for screw placement and IONM modalities. Opinions on IONM use during stereotactic or robotic navigation were also obtained. Responses were analyzed using Pearson's Chi Square and ANOVA tests via R software. Of 188 responses, 35.5% (n=67) reported 1-10 years of experience and 64.5% (n=121) reported ≥11 years. Less experienced neurosurgeons utilized stereotactic navigation more than those with greater experience (p < 0.001). Seasoned neurosurgeons utilized fluoroscopic guidance more often (p = 0.038). Less experienced neurosurgeons employed 1.69 (±0.11) techniques for their fixation surgeries compared to 1.50 (±0.0.8) for more experienced neurosurgeons. Robotic navigation utilization was low and comparable between the groups. Surgeons employing multiple techniques utilized t-EMG the most (62.1%, p = 0.024). No strong opinions emerged on the necessity of multi-modality IONM with robotic or stereotactic navigation. This national survey shows that stereotactic navigation is the predominant technique for pedicle screw placement among less experienced neurosurgeons, with seasoned neurosurgeons leaning towards fluoroscopic guidance. Robotic guidance was the least utilized technique with no observed difference based on experience. Neurosurgeons employing multiple techniques use IONM the most, compared with surgeons who only use stereotactic navigation and/or robotic guidance.

Current research status and prospects for clinical application of robotics in spinal surgery

With the rapid advancement of artificial intelligence and the increasing integration of medical engineering, robot-assisted (RA) technology in spinal surgery has made significant strides, with its clinical application range continuously expanding. This article provides a comprehensive review of relevant literature on spinal surgery robots over the past decade, summarizing recent advancements in screw placement techniques such as cervical, thoracic, and lumbar pedicle screws; cortical bone trajectory (CBT) screws; cervical lateral mass screws; and S2 sacroiliac (S2AI) screws. It also discusses RA-guided targeted puncture and endoscope placement through intervertebral foramen as well as decompressive laminectomy procedures. Furthermore, this article systematically analyzes the advantages and disadvantages of RA technology while elucidating its accuracy, safety, and practicality. We believe that this article will help clinicians to gain a deeper understanding of the current clinical application status of spinal surgery robots while promoting further enhancements and wider adoption of RA technology to ultimately benefit more patients.

O-arm navigation without apnoea in thoracolumbar and lumbar spine surgery: Outcomes and considerations in a prospective study

BackgroundIntra operative three dimensional navigation-assisted pedicle screw insertion typically requires apnoea for reliable image production. However this carries potential risks to the physiologically compromised patients such as patients having COPD, obesity, cardiac illnesses, and anaemia. In such patients’ safe apnoea time may be as low as 1 min, and can cause life threatening complications. Therefore, this study was done to evaluate the accuracy of thoracolumbar and lumbar pedicle screw insertion using O-arm without using apnoea during imaging, to prevent such possible complications. MethodsThis is a single centre prospective study of 238 patients treated with pedicle screw implantation under O-arm guidance, without using apnoea while imaging. The pedicle breach rate during screw insertion was graded on Gertzbein classification. Also, two senior spine surgeons independently evaluated motion artifacts in the intra operative images and rated them as ‘Significant’ or ‘Non-Significant’ for the procedure. Values of p < 0.05 were considered statistically significant. ResultsDespite not using apnoea in 238 patients with 1120 screws, there were nil screw related complications. Only in one paediatric case of dorsal spine deformity, there were blurred and inaccurate images because of chest expansion, without apnoea. Hence he was given apnoea to render the image reliable for pedicle screw insertion. The screw placement in the pedicles was checked intraoperatively and graded for breach. Grade 2 breach were seen in only 2 cases (n = 3 screws) which were revised intra operatively. The interobserver agreement on motion artifacts was good (κ = 0.565, p < 0.001). ConclusionsThe results of pedicular screw insertion performed without induced apnea are comparable to those achieved with apnea when using O-arm imaging. This technique has proven to be a safe and reliable method for pedicle screw insertion in the thoracolumbar and lumbar spine, potentially mitigating physiological complications. Nonetheless, even minor motion artifacts, on the order of a few millimeters, can significantly impact outcomes in the cervical and upper thoracic spine. Therefore, further research is warranted to evaluate the efficacy and safety of this approach in these regions of the spine.

Lumbar Pedicle Morphometry in a Sample of the Egyptian Population, Parameters and Measures to Safe Screw Placement

Lumbar Pedicle Morphometry in a Sample of the Egyptian Population, Parameters and Measures to Safe Screw Placement

Percutaneous lumbopelvic fixation is effective in the management of unstable transverse sacral fractures

ObjectivesHistorically, fractures causing lumbopelvic dissociation have been managed with open lumbosacral fusion and instrumentation. Our aim was to evaluate outcomes and complications following surgical management of unstable transverse sacral fractures with percutaneous lumbopelvic fixation. MethodsDesign: Retrospective case series. Setting: Academic Single Center, Level I Trauma Center. Patient Selection Criteria: Patients with lumbopelvic dissociation undergoing surgery. Outcome Measures and Comparisons: Patient demographics, mechanism of injury, ISS, associated injuries, radiographic classification (Roy-Camille), patient-reported outcomes (PROMIS PI, PF, D, and ODI), and complications were collected. Results27 patients were enrolled with an average follow-up of 18.7 ± 17.6 months and age of 54.4 ± 25.1 years. All patients underwent lumbar pedicle screw and iliac screw placement. Sacral laminectomy was performed if the patient had a preoperative neurological deficit. Patients were counseled on instrumentation removal at 6–12 months. 67 % of patients sustained a fall, and 33 % were involved in an MVA. 52 % were Roy-Camille Type 2, and 32 % and 20 % were Types 1 and 3, respectively. The mean EBL was 261 ± 400 ml. 37 % required concurrent sacral laminectomy. There were no intraoperative complications and four postoperative complications, including surgical site infection, rod dislodgment, and deep venous thrombosis. 63 % underwent removal of instrumentation after fracture healing. ODI scores significantly improved from 6 weeks post-op (35.5 ± 4.5) to one-year follow-up (18.3 ± 9.6, p = 0.005), two-year follow-up (20.3 ± 10.0, p = 0.03), and final follow-up (16.4 ± 8.8, p = 0.002). Statistically significant improvements were observed in the PROMIS PI, PF, and D domains (p < 0.05). ConclusionOur study demonstrates that lumbopelvic instrumentation leads to successful management of unstable transverse sacral fractures, with improvement in PRO. The combination of percutaneous instrumentation without arthrodesis did not result in any fracture non-union. Level of evidenceLevel IV

Comparison of rostral facet joint violations in robotic- and navigation-assisted pedicle screw placement for adult lumbar spine instrumentation

BACKGROUND CONTEXTFacet joint violation by pedicle screws may lead to adjacent-segment disease and postoperative pain. Previous studies have reported the incidence of rostral facet joint violation using various pedicle screw insertion techniques. However, the incidence of facet joint violations with robotic guidance has not been determined. PURPOSETo investigate and compare the incidence of rostral facet joint violation by pedicle screws under robotic guidance and computerized tomography (CT) navigation guidance. STUDY DESIGN/SETTINGRetrospective matched cohort. PATIENT SAMPLEAll patients who underwent robotic-assisted lumbar fusion at a major spine center up until 2023 were retrospectively identified and matched 1:3 to patients undergoing CT navigation guidance based by on age, sex, rostral vertebral level, and length of construct. Inclusion criteria consisted of age greater than 18 years, bilateral pedicle screw fixation, and presence of a postoperative CT scan of the lumbar spine or abdomen/pelvis at any point in the post-operative period. OUTCOME MEASURESRostral facet joint violations. METHODSDescriptive statistics were used to compare cohorts: frequencies, chi-squared analysis for categorical variables, and t-test for continuous variables. RESULTSA total of 408 rostral pedicle screws were implanted in 204 patients (Robot: 102; Navigation: 306). Overall, 13 (12.3%) rostral facet joint violations were observed in the robot cohort and 75 (24.5%) in the navigation cohort (p=.01). Specifically, fewer robotic violations were observed at the L2 (3.5% vs. 32.1%, p=.003) and L3 levels (3.9% vs. 18.1%, p=.08) compared to navigation. No difference was observed at L4 and L5. Bilateral violations are significantly reduced with robotic approaches (5.3% vs. 14.4%, p=.03). Lastly, more facet joint violations were observed during open approaches (robot: 18.8%, navigation: 27.3%) than percutaneous approaches (robot: 11.6%, navigation: 7.1%) in both groups (p<.001). The rate of L4 facet violations was 18.8% in the robotic cohort and 27.3% in the navigation cohort. The rate of L5 facet violations was 31.3% in the robotic cohort and 29.2% in the navigation cohort. CONCLUSIONSUse of robotic assistance in lumbar pedicle screws significantly reduced the rate of rostral facet joint violations compared to navigation guidance at L2 and L3 levels, but not at L4 and L5, with facet violations approaching nearly one-third of the patients at L5 screws. Rostral facet violations can play a significant role in adjacent segment degeneration and disease. Technical factors and trajectory issues likely play a role and addressing these components should minimize unintended facet violation and proximal adding on.

Lumbar Pedicle Dimensions Using CT Scan in Adults of South-Eastern Nigeria as Related to Transpedicular Fixation.

Transpedicular fixation depends on accuracy of the entry points, angle of insertion and pedicular isthmus width for adequate screw insertion. Preoperative measurements of pedicle dimensions reduce the chances of failure during insertion. These pedicle dimensions (transverse diameter, longitudinal diameter, and maximum length of purchase [MLP]) vary with sex and race. Such data, from a large-scale study, are not available for our population. The study aims to evaluate the dimensions of pedicle that are relevant for pedicle screw fixation in Southeast Nigerian population. A prospective multi-slice CT based clinical anatomy study done at Memfys Hospital for Neurosurgery, Enugu. This study is on the lumbar pedicle dimensions that are related to transpedicular fixation (transverse and longitudinal diameters of the pedicle, MLP, pedicle transverse and longitudinal angles of inclination). Sample size (273) was calculated with the confidence interval formula based on the number of patients that present for images. Consent and ethical approval were obtained. The mean values are as follow: LD1 8.22 mm, LD2 7.73 mm, LD3 7.40 mm, LD4 7.16 mm, LD5 6.87 mm TD1 5.05 mm, TD2 5.31 mm, TD3 6.72 mm, TD4 8.27 mm, TD5 11.31 mm, MLP1 46.60 mm, MLP2 47.97 mm, MLP3 47.14 mm, MLP4 45.54 mm, MLP5 43.47 mm TA1 17.8°, TA2 19.34°, TA3 20.80°, TA4 22.00°, TA5 25.70° LA1 19.42°, LA2 18.61°, LA3 18.00°, LA4 17.09°, LA5 16.40°. Unlike transverse diameter, transverse angle, longitudinal dimension, longitudinal angle (LA), MLP there was significant correlation between age and mean LA. The mean values also correlated significantly with the gender. The mean values varied with the different vertebral levels and was good correlations between some of the parameters with age and gender.

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

To introduce and evaluate an MRI-based PBQ score to determine its effectiveness in predicting pedicle screw loosening following lumbar fusion surgery. 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. 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%. 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.

Comparison of accuracy, revision, and perioperative outcomes in robot-assisted spine surgeries: systematic review and meta-analysis.

Pedicle screw placement guidance is critical in spinal fusions, and spinal surgery robots aim to improve accuracy and reduce complications. Current literature has yet to compare the relative merits of available robotic systems. In this review, the authors aimed to 1) assess the current state of spinal robotics literature; 2) conduct a meta-analysis of robotic performance based on accuracy, speed, and safety; and 3) offer recommendations for robotic system selection. Following PRISMA guidelines, the authors conducted a systematic literature review across PubMed, Embase, Cochrane Library, Web of Science, and Scopus as of April 28, 2022, for studies on approved robots for placing lumbar pedicle screws. Three reviewers screened and extracted data relating to the study characteristics, accuracy rate, intraoperative revisions, and reoperations. Secondary performance metrics included operative time, blood loss, and radiation exposure. The authors statistically compared the performance of the robots using a random-effects model to account for variation within and between the studies. Each robot was also compared with performance benchmarks of traditional techniques including freehand, fluoroscopic, and CT-navigated insertion. Finally, we performed a Duval and Tweedie trim-and-fill test to assess for the presence of publication bias. The authors identified 46 studies, describing 4670 patients and 25,054 screws, that evaluated 4 different robotic systems: Mazor X, ROSA, ExcelsiusGPS, and Cirq. The weighted accuracy rates of Gertzbein-Robbins classification grade A or B screws were as follows: ExcelsiusGPS, 98.0%; ROSA, 98.0%; Mazor, 98.2%; and Cirq, 94.2%. No robot was significantly more accurate than the others. However, the accuracy of the ExcelsiusGPS was significantly higher than that of traditional methods, and the accuracies of the Mazor and ROSA were significantly higher than that of fluoroscopy. The intraoperative revision rates were Cirq, 0.55%; ROSA, 0.91%; Mazor, 0.98%; and ExcelsiusGPS, 1.08%. The reoperation rates were Cirq, 0.28%; ExcelsiusGPS, 0.32%; and Mazor, 0.76% (no reoperations were reported for ROSA). Operative times were similar for all robots. Both the ExcelsiusGPS and Mazor were associated with significantly less blood loss than the ROSA. The Cirq had the lowest radiation exposure. Robots tended to be more accurate and generally their use was associated with fewer reoperations and less blood loss than freehand, fluoroscopic, or CT-navigated techniques. Robotic platforms perform comparably based on key metrics, with high accuracy rates and low intraoperative revision and reoperation rates. The spinal robotics publication rate will continue to accelerate, and choosing a robot will depend on the context of the practice.

Early Experience With Novel Molded Allograft Anchors for the Management of Screw Loosening in Elderly Patients With Reduced Bone Density in Primary and Revision Lumbar Surgery.

Various strategies have been used to reduce pedicle screw loosening following lumbar instrumented fusion, but all strategies have limitations. In this prospective multicenter cohort study, outcomes of elderly patients with reduced bone density who underwent primary or revision fusion surgery using a novel technique of pedicle screw augmentation with demineralized bone fiber (DBF) anchors were evaluated. This study included elderly patients (aged >65 years) with dual-energy x-ray absorptiometry-confirmed reduced bone density who required lumbar pedicle screw fixation and were treated with supplemental DBF allograft anchors during primary or revision surgery. The need for DBF anchors was determined by evaluating preoperative computed tomography (CT) scans (for revision surgery) and by the surgeons' tactile feedback intraoperatively during pedicle screw insertion and removal. After determining the pedicle screw void diameter with a sizing instrument, DBF anchors and pedicle screws of the same diameter were placed into the void. CT scans were obtained on postoperative day 2 to assess pedicle breach, pedicle fracture, or anchor material extrusion and at 6 and 12 months postoperatively to assess screw loosening. Thereafter, to minimize radiation exposure, CT scans were only performed for recurrence of pain. Twenty-three patients (79% women; mean age, 74 years) received 50 lumbosacral pedicle screws augmented with DBF anchors. Most surgeries (n = 18, 78%) were revisions, and most anchors were inserted into revision pedicle screw trajectories (n = 33, 66%). Day-2 CT scans revealed no pedicle breach/fracture or extrusion of anchor material. During a mean follow-up of 15 months (12-20 months), no screw loosening was detected, and no patient required pedicle screw revision surgery. There were no adverse events attributable to DBF allografts. DBF allograft anchors appear to be safe and effective for augmenting pedicle screws during revision surgeries in female elderly patients with reduced bone density. Clinically, DBF reduced the rate of pedicle screw loosening in patients with reduced bone density. A significant reduction in screw loosening can decrease the need for revision surgeries, which are costly and carry additional risks. Enhanced bone integration from the DBF may promote better healing and long-term stability.

Feasibility and accuracy of intraosseous endoscopy for inspection of thoracolumbar and lumbar pedicle drill tracts in a canine large-breed cadaveric model.

To evaluate the feasibility of endoscopic inspection of thoracolumbar and lumbar pedicle tracts in a canine large-breed model and its accuracy for the detection of breached versus nonbreached tracts. 2 greyhound cadavers. CT scans of 2 greyhound cadavers from the sixth thoracic vertebra to the sacrum were obtained. Fifty-six pedicles were randomized to have drill tracts with different modified Zdichavsky grades (nonbreached, partial/full medial breach, or partial/full lateral breach) using 3-D-printed guides. Endoscopy was performed on a single occasion from October 9 to 10, 2023, using a 1.9-mm 0-degree needle arthroscope in a randomized blinded fashion. The grading of drill tracts was performed on postoperative CT. Specificity, sensitivity, positive and negative predictive values, and time to assign endoscopic grade were investigated. Postoperative CT confirmed 43 nonbreached tracts, 7 medial breaches (partial/full), and 5 lateral breaches (partial/full). One tract was excluded because of guide misplacement. Intraosseous endoscopy was successfully performed in the remaining 55 drill tracts. Sensitivity to detect medial and lateral breaches was 71.4% and 60.0%. Negative predictive value was 93.1%. Specificity was 94.2%. Positive predictive value for detection of medial and lateral breaches was 83.3% and 54.5%. Median (range) time to assign an endoscopic grade was 118 (30 to 486) seconds. Intraosseous endoscopy of pedicle drill tracts may be a useful adjunct technique during pedicle screw/pin placement in dogs.

Importance of the lumbar paraspinal muscles on the maintenance of global sagittal alignment after lumbar pedicle subtraction osteotomy.

There are limited data about the influence of the lumbar paraspinal muscles on the maintenance of sagittal alignment after pedicle subtraction osteotomy (PSO) and the risk factors for sagittal realignment failure. The authors aimed to investigate the influence of preoperative lumbar paraspinal muscle quality on the postoperative maintenance of sagittal alignment after lumbar PSO. Patients who underwent lumbar PSO with preoperative lumbar MRI and pre- and postoperative whole-spine radiography in the standing position were included. Spinopelvic measurements included pelvic incidence, sacral slope, pelvic tilt, L1-S1 lordosis, T4-12 thoracic kyphosis, spinosacral angle, C7-S1 sagittal vertical axis (SVA), T1 pelvic angle, and mismatch between pelvic incidence and L1-S1 lordosis. Validated custom software was used to calculate the percent fat infiltration (FI) of the psoas major, as well as the erector spinae and multifidus (MF). A multivariable linear mixed model was applied to further examine the association between MF FI and the postoperative progression of SVA over time, accounting for repeated measures over time that were adjusted for age, sex, BMI, and length of follow-up. Seventy-seven patients were recruited. The authors' results demonstrated significant correlations between MF FI and the maintenance of corrected sagittal alignment after PSO. After adjustment for the aforementioned parameters, the model showed that the MF FI was significantly associated with the postoperative progression of positive SVA over time. A 1% increase from the preoperatively assessed total MF FI was correlated with an increase of 0.92 mm in SVA postoperatively (95% CI 0.42-1.41, p < 0.0001). This study included a large patient cohort with midterm follow-up after PSO and emphasized the importance of the lumbar paraspinal muscles in the maintenance of sagittal alignment correction. Surgeons should assess the quality of the MF preoperatively in patients undergoing PSO to identify patients with severe FI, as they may be at higher risk for sagittal decompensation.

Beyond Traditional Training: Exploring the Benefits of Virtual Reality Simulator in Lumbar Pedicle Screw Insertion - A Randomized Controlled Trial

This study compares the effectiveness of virtual reality simulators (VRS) and a saw bone model for learning lumbar pedicle screw insertion (LPSI) in neurosurgery. A single-center, cross-sectional, randomized controlled laboratory investigation was conducted involving residents and fellows from a tertiary care referral hospital. Participants were divided into two groups (A and B). Group A performed 3 LPSI tasks: the first on a saw bone model, the second on VRS, and the third on another saw bone model. Group B completed 2 LPSI tasks: the first on a saw bone model and the second on another saw bone model. The accuracy of LPSI was evaluated through noncontrast computed tomography scans for the saw bone models, while the in-built application of VRS was utilized to check for accuracy of screw placement using the simulator. The study included 38 participants (19 in each group). Group A participants showed reduced mean entry point error (0.11mm, P 0.024), increased mean purchase length (4.66cm, P 0.007), and no cortical breaches (P 0.031) when placing the second saw bone model screw. Similar improvements were observed among group A participants in PGY 1-3 while placing the second saw bone model screws. Virtual reality simulators (VRS) prove to be an invaluable tool for teaching complex neurosurgical skills, such as LPSI, to trainees. This technology investment can enhance the learning curve while maintaining patient safety.

Predicting Complications in 153 Lumbar Pedicle Subtraction Osteotomies by a Single Surgeon Over a 6-Year Period.

Pedicle subtraction osteotomy (PSO) is a complex surgical procedure that provides correction of moderate sagittal imbalance. Surgical complications have adverse effects on patient outcomes and healthcare costs, making it imperative for clinical researchers to focus on minimizing complications. However, when it comes to risk modeling of PSO surgery, there is currently no consensus on which patient characteristics or measures should be used. This study aimed to describe complications and compare the performance of various sociodemographic characteristics, surgical variables, and established risk indices in predicting postoperative complications, infections, and readmissions after lumbar PSO surgeries. A review was conducted on 191 patients who underwent PSO surgery at a single institution by a single fellowship-trained orthopaedic spine surgeon between January 1, 2018, and December 31, 2021. Demographic, intraoperative, and postoperative data within 30 days, 1 year, and 2 years of the index procedure were evaluated. Descriptive statistics, t -test, chi-squared analysis, and logistic regression models were used. Intraoperative complications were significantly associated with coronary artery disease (odds ratios [OR] 3.95, P = 0.03) and operating room time (OR 1.01, P = 0.006). 30-day complications were significantly cardiovascular disease (OR 2.68, P = 0.04) and levels fused (OR 1.10, P = 0.04). 2-year complications were significantly associated with cardiovascular disease (OR 2.85, P = 0.02). 30-day readmissions were significantly associated with sex (4.47, 0.04) and length of hospital stay (χ 2 = 0.07, P = 0.04). 2-year readmissions were significantly associated with age (χ 2 = 0.50, P = 0.03), hypertension (χ 2 = 4.64, P = 0.03), revision surgeries (χ 2 = 5.46, P = 0.02), and length of hospital stay (χ 2 = 0.07, P = 0.03). This study found that patients with coronary vascular disease and longer fusions were at higher risk of postoperative complications and patients with notable intraoperative blood loss were at higher risk of postoperative infections. In addition, physicians should closely follow patients with extended postoperative hospital stays, with advanced age, and undergoing revision surgery because these patients were more likely to be readmitted to the hospital.

Morphometric Study of Lumbar Vertebral Pedicles by Using Computed Tomography among Adults in Kano, Nigeria

Abstract Context: Precise anatomical knowledge of lumbar pedicle dimensions is necessary to make a clinical diagnosis of lower back pain, and any structural deviation of the pedicles may result in interference with the weight transmission mechanism and compression of neural structures. Aim: To evaluate the morphometric dimensions of lumbar vertebral pedicles among normal adults in Kano by using computerized tomography scan images. Materials and Method: This was a hospital-based cross-sectional study that was conducted in the radiology department of Aminu Kano Teaching Hospital (AKTH). This study was conducted over 1 year and included 110 adults aged 18–75 years involving both sexes in Kano, using their CT scan images from L1 to L5, following IRB ethics approval. Each vertebral pedicle was measured in transverse and sagittal planes. The measurements included the pedicle width (PW), sagittal pedicle height (SPH), and the pedicle chord length (PCL) of individual pedicles. The mean and standard deviations for each measurement parameter were determined, and parametric correlation tests were performed to determine the relationships between age, sex, and ethnicity. Statistical Analysis Used: Data analysis was performed using the statistical software package IBM SPSS Statistics version-23 for Windows. The significance level was considered at P &lt; 0.05. Results: Mean PW size increased craniocaudally along the lumbar spine from L1 (7.49 ± 1.52 mm) to L5 (14.31 ± 1.93 mm). A gradual decrease in mean SPH sizes from L1 (14.53 ± 1.32 mm) to L5 (11.73 ± 1.38 mm) was noted, while mean PCL showed an irregular “U” pattern, with the smallest size at L4 (44.63 ± 3.42 mm) and highest at L2 (46.80 ± 3.85 mm). All measured dimensions were significantly higher in the right pedicles and among male subjects (P &lt; 0.05). Age and ethnicity did not consistently affect pedicle dimensions (P &gt; 0.05). Conclusion: This study observed right pedicle dimensions and male subjects as having significantly larger pedicle diameters, with age and ethnicity not having a significant effect on pedicle sizes across all vertebral levels.

Posterior endpoint determination of the lumbar pedicle central axis on the anterior–posterior fluoroscopic image for pedicle screw insertion

The transpedicular procedure has been widely used in spinal surgery. The determination of the best entry point is the key to perform a successful transpedicular procedure. Various techniques have been used to determine this point, but the results are variable. This study was carried out to determine the posterior endpoint of the lumbar pedicle central axis on the standard anterior–posterior (AP) fluoroscopic images. Computer-aided design technology was used to determine the pedicle central axis and the posterior endpoint of the pedicle central axis on the posterior aspect of the vertebra. The standard AP fluoroscopic image of the lumbar vertebral models by three-dimensional printing was achieved. The endpoint projection on the AP fluoroscopic image was determined in reference to the pedicle cortex projection by the measurements of the angle and distance on the established X–Y coordinate system of the radiologic image. The projection of posterior endpoint of the lumbar pedicle central axis were found to be superior to the X-axis of the established X–Y coordinate system and was located on the pedicle cortex projection on the standard AP fluoroscopic image of the vertebra. The projection point was distributed in different sectors in the coordinate system. It was located superior to the X-axis by 18° to 26° at L1, while they were located superior to the X-axis by 12° to 14° at L2 to L5. The projections of posterior endpoints of the lumbar pedicle central axis were located in different positions on the standard AP fluoroscopic image of the vertebra. The determination method of the projection point was helpful for selecting an entry point for a transpedicular procedure with a fluoroscopic technique.

Revision of Harrington rod constructs: a single-center's experience with this homogenous adult spinal deformity population at a minimum 2-year follow-up.

To evaluate radiographic and clinical outcomes following revision surgery after HRC fusions. Single-institution, retrospective study of patients revised following HRC with minimum 2-year follow-up post-revision. Demographics, perioperative information, radiographic parameters, complications, and Oswestry disability index (ODI) scores were collected. Radiographic parameters included global alignment, coronal and sagittal measurements pre and postoperatively, as well as final follow-up time points. 26 patients were included with a mean follow-up of 3.3 ± 1.1years. Mean age was 55.5 ± 7.8years, BMI 25.2 ± 5.8, and 22 (85%) were females. Instrumented levels increased from 9.7 ± 2.8 to 16.0 ± 2.2. Five (19.2%) patients underwent lumbar pedicle subtraction osteotomies, and 23 (88.4%) had interbody fusions. Patients significantly improved in all radiographic parameters at immediate and final follow-up (p < 0.005), except for thoracic kyphosis and pelvic incidence (p > 0.05). Correction was maintained from immediate postop to final follow-up (p > 0.05). 20 (76.9%) of patients experienced a complication at some point within the follow-up period with the most common being a lumbar nerve root deficit (n = 7). However, only one patient had a nerve root deficit at final follow-up, that being a 4/5 unilateral anterior tibialis function. 5 (19.2%) patients required further revision within a mean of 1.8 ± 1.1years. On average, patients had an improvement in ODI score by final follow-up (35.6 ± 16.8 vs 25.4 ± 19.8, p = 0.035). Patients revised for HRCs significantly improve, both clinically and radiographically by final follow-up. This group did have a propensity for distal lumbar root neurological issues, which were common but all patients except for one, recovered to full strength by two-year follow-up.

Novel Screw Placement Method for Extremely Small Lumbar Pedicles in Scoliosis.

Study Design: Consecutive case series. Objective: To propose a screw placement method in patients with extremely small lumbar pedicles (ESLPs) (<2 mm) to maintain screw density and correction power, without relying on the O-arm navigation system. Summary of Background Data: In scoliosis surgery, ESLPs can hinder probe passage, resulting in exclusion or substitution of the pedicle screws with a hook. Screw density affects correction power, making it necessary to maximize the number of screw placements, especially in the lumbar curve. Limited studies provide technical guidelines for screw placement in patients with ESLPs, independent of the O-arm navigation system. Methods: We enrolled 19 patients who underwent scoliosis correction surgery using our novel screw placement method for ESLPs. Clinical, radiological, and surgical parameters were assessed. After posterior exposure of the spine, the C-arm fluoroscope was rotated to obtain a true posterior-anterior view and both pedicles were symmetrically visualized. An imaginary pedicle outline was presumed based on the elliptical or linear shadow from the pedicle. The screw entry point was established at a 2 (or 10) o'clock position in the presumed pedicle outline. After adjusting the gear-shift convergence, both cortices of the transverse process were penetrated and the tip was advanced towards the lateral vertebral body wall, where an extrapedicular screw was placed with tricortical fixation. Results: Out of 90 lumbar screws in 19 patients, 33 screws were inserted using our novel method, without correction loss or complications during an average follow-up period of 28.44 months, except radiological loosening of one screw. Conclusions: Our new extrapedicular screw placement method into the vertebral body provides an easy, accurate, and safe alternative for scoliosis patients with ESLPs without relying on the O-arm navigation system. Surgeons must consider utilizing this method to enhance correction power in scoliosis surgery, regardless of the small size of the lumbar pedicle.