Pedicle Screw Placement Research Articles

First case report using optical topographic-guided navigation in revision spinal fusion for calcified thoracic disk

Computer assisted navigation systems are frequently used in spine surgery to improve the accuracy of pedicle screw placement. The 7D Surgical System utilizes optical topographic imaging (OTI) with a camera positioned directly above the surgical field to perform rapid registration from a pre-operative CT scan onto anatomical landmarks with zero intra-operative radiation exposure. This current technology requires an open approach with well-exposed bony anatomy, raising concerns about using the 7D Surgical System in revision surgery, where typical anatomical landmarks may be altered, missing, or obscured by prior hardware. To overcome this, the 7D Surgical System is capable of registering off prior hardware. Here, we present the first published report of 7D Surgical System’s registration off prior hardware in a revision spinal fusion. The registration was accurate, and the workflow was easy and efficient with one registration required for 3 levels of instrumentation and discectomy/corpectomy. This demonstrates that the 7D Surgical System can be used in revision cases with altered, missing, or obscured anatomy.

Accuracy and Efficiency of Fusion Robotics™ Versus Mazor-X™ in Single-Level Lumbar Pedicle Screw Placement.

IntroductionThere has been a surge in robot utilization in spine surgery over the past five years with the rapid development of new spine robotic platforms. This study aimed to compare a new robotic spine platform from Fusion RoboticsTM (Fusion Robotics, Helena, MT) with the widely used Mazor-XTM Stealth Edition robotic platform (Medtronic, Dublin, Ireland) in terms of workflow and lumbar pedicle screw placement accuracy.MethodsA cadaver lab was conducted, which included four procedures with single-level lumbar pedicle screw placement using the Fusion RoboticsTM system. These four procedures were compared to four propensity-score matched cases with single-level lumbar pedicle screw placement using the Mazor-XTM Stealth Edition. A single surgeon performed all surgeries. The cases were matched in terms of demographics (age, sex, race, BMI) and comorbidities (Charlson Comorbidity Index score). The primary outcome measure was the operative workflow efficiency (duration as measured with a stopwatch by an independent observer). The secondary outcome measures were pedicle screw accuracy and accuracy to plan.ResultsAfter propensity-score matching, there were four cases in each group with no significant between-group differences in terms of sex, race, BMI, or surgical levels; however, there were significant differences in terms of age (p=0.01) and comorbidities (p<0.001). The workflow efficiency measurement showed that the Fusion RoboticsTM platform had a significantly shorter duration in terms of the system set-up time, planning to in-position time, and total procedure time (p<0.05). However, there was no significant difference between the robotic platforms in terms of creating a sterile barrier, scanning and importing images, creating a plan, screw placement, screw accuracy, and screw accuracy to plan.ConclusionBased on our findings, the Fusion RoboticsTM platform had a significantly shorter procedure workflow duration while maintaining the same accuracy as the most commonly used robotic platform (Mazor-XTM). This is the first study to directly compare different spine surgery robotic systems.

Occipitocervical instrumented fixation utilising patient-specific C2 3D-printed spinal screw trajectory guides in complex paediatric skeletal dysplasia.

Instability of the craniocervical junction in paediatric patients with skeletal dysplasia poses a unique set of challenges including anatomical abnormalities, poor bone quality, skeletal immaturity and associated general anaesthetic risks. Instrumented fixation provides optimal stabilisation and fusion rates. The small vertebrae make the placement of C2 pedicle screws technically demanding with low margins of error between the spinal canal and the vertebral artery. We describe a novel clinical strategy utilising 3D-printed spinal screw trajectory guides (3D-SSTG) for individually planned C2 pedicle and laminar screws. The technique is based on a pre-operative CT scan and does not require intraoperative CT imaging. This reduces the radiation burden to the patient and forgoes the associated time and cost. The time for model generation and sterilisation was < 24h. We describe two patients (3 and 6years old) requiring occipitocervical instrumented fixation for cervical myelopathy secondary to Morquio syndrome with 3D-SSTGs. In the second case, bilateral laminar screw trajectories were also incorporated into the same guide due to the presence of high-riding vertebral arteries. Registration of the postoperative CT to the pre-operative imaging revealed that screws were optimally placed and accurately followed the predefined trajectory. To our knowledge, we present the first clinical report of 3D-printed spinal screw trajectory guides at the craniocervical junction in paediatric patients with skeletal dysplasia. The novel combination of multiple trajectories within the same guide provides the intraoperative flexibility of potential bailout options. Future studies will better define the potential of this technology to optimise personalised non-standard screw trajectories.

Spinal Pedicle Morphometry using Multidetector CT—An experience from the Indian Subcontinent

Abstract Introduction For safe pedicle screws placement, knowledge of pedicle morphometry is essential, because an inconsistency between pedicle width and the screw diameter may lead to severe complications like nerve, vessel or visceral injuries. Objectives To study the spinal pedicle width and height of lumbar spine, using multidetector CT (MDCT), among the Indian population. To study the spinal pedicle angulation of lumbar spine, using MDCT, among the Indian population. Method The study was conducted at a tertiary care multispecialty hospital. In the present study, a total of 321 patients were included, who underwent MDCT scan without contrast at our institution, over a period of 2 years, from May 2017 to May 2019. The study population (n = 321) was divided into different subgroups on the basis of the age. The data was taken from the workstation. Comparison was made separately between each subgroup. Results In our subset of population, the 10 to 90 years age group, pedicle dimensions are as follow: The pedicle diameter from L1 to L5 is 4.46 to 11.92 mm. The pedicle height from L1 to L5 is 7.38 to 11.01 mm. The pedicle axial angulation from L1 to L5 is 22.27 to 36.08 degree. The pedicle lateral angulation from L1 to L5 is 16.12 to 22.47 degree. Conclusion Knowledge of the pedicle morphometry (pedicle width, height and angulation) of lumbar spine will help the neurosurgeons standardize the size of pedicle screws which is required for spinal fixation surgery at various lumbar vertebra levels.

Subaxial Cervical Pedicle Screw Placement With Direct Visualization of Pedicle Borders: 2-Dimensional Operative Video.

Pedicle screws provide superior fixation of the subaxial cervical spine to other techniques. However, a high degree of accuracy is required for safe placement given the proximity of pedicles to critical neurovascular structures. A variety of techniques are described to maximize accuracy, including freehand, fluoroscopy-guided, and neuronavigation-based methods. We present a technique for the placement of pedicle screws in the subaxial cervical spine using direct visualization of the pedicle in a patient who required an occipito-cervical fusion construct in the setting of a C2 chordoma. A laminotomy or laminectomy is performed laterally to allow for visualization of the medial, superior, and inferior walls of the pedicle. The entry point for screw placement is determined based on pedicle anatomy and is typically 1 to 2 mm lateral to the midpoint of the lateral mass, just below the base of the superior articulating process. Screw trajectory is determined by visualizing the pedicle borders and is aimed at the junction of the medial pedicle wall, with the posterior vertebral body down the pedicle axis. Tactile feedback (loss of resistance) is used to assess for a breach while drilling. The cannulation is then tapped, and the screw is placed in a standard fashion. Direct visualization of pedicle anatomy can be a useful adjunct to guide the safe placement of subaxial pedicle screws when superior fixation is required or when normal anatomy is distorted. The technique may be combined with fluoroscopic or navigation-based techniques to provide real-time anatomic guidance during screw placement. The patient provided informed, written consent for this procedure before surgery. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

A Comparison of Drill Guiding and Screw Guiding 3D-Printing Techniques for Intra- and Extrapedicular Screw Insertion.

Screw randomized cadaveric study. To compare the accuracy of three-dimensional (3D)-printed drill guides versus additional screw guiding techniques for challenging intra- and extrapedicular screw trajectories. Pedicle screw placement can be technically demanding, especially in syndromic scoliosis with limited bone stock. Recently, 3D-printing and virtual planning technology have become available as new tools to improve pedicle screw insertion. Differences in techniques exist, while some focus on guiding the drill, others also actively guide subsequent screws insertion. The accuracy of various 3D-printing-assisted techniques has been studied; however, direct comparative studies have yet to determine whether there is a benefit of additional screw guidance. Two cadaveric experiments were conducted to compare drill guides with two techniques that introduce additional screw guiding. The screw guiding consisted of either k-wire cannulated screws or modular guides, which were designed to guide the screw in addition to the drill bit. Screws were inserted intra- or extrapedicular using one of each methods according to a randomization scheme. Postoperative computed tomography scanning was performed and fused with the preoperative planning for detailed 3D screw deviation analysis. For intrapedicular screw trajectories malpositioning was low (2%) and the modular guides revealed a statistically significant increase of accuracy (P = 0.05) compared with drill guides. All techniques showed accurate cervical screw insertion without breach. For the extrapedicular screw trajectories both additional screw guiding methods did not significantly (P = 0.09) improve accuracy and malpositioning rates remained high (24%). In this cadaveric study it was found that the additional screw-guiding techniques are not superior to the regular 3D-printed drill guides for the technically demanding extrapedicular screw technique. For intrapedicular screw insertion, modular guides can improve insertion; however, at cervical levels regular 3D-printed drill guides already demonstrated very high accuracy and therefore there is no benefit from additional screw guiding techniques. 3.

Robotic-assisted percutaneous iliac screw fixation for destructive lumbosacral metastatic lesions: an early single-institution experience.

Robotic-assisted surgery is becoming more widely applied in surgical subspecialties due to its intraoperative and postoperative advantages such as minimally invasive approach, reduced blood loss, shorter hospital stay, and decreased incidence of postoperative complications. However, robotic devices were only recently introduced in the field of spinal surgery. Specifically, percutaneous approaches involving computer-assisted image guidance are relatively new in iliac screw fixation. Previous methods focused on the use of S2-alar-iliac (S2AI) screw fixation which allows for pelvic fixation without a need for side connectors. However, for patients with destructive lesions of the sacrum, placement of these S2AI screws may not be feasible. The purpose of this technical note is to illustrate the implementation of robotic-assisted percutaneous iliac screw fixation in two cases which allows for minimally invasive attachment to the proximal lumbar screws without a side connector and eliminates a potential source of instrumentation failure. Robotic-assisted percutaneous iliac screw fixation was performed on two patients. The robotics system was used to merge the fluoroscopic images with intraoperative computed tomography (CT) images to plan the trajectories for placement of bilateral pedicle and iliac screws. Intraoperative CT scan was again performed to confirm proper placement of all screws. Rods were then engaged bilaterally with the pedicle and iliac screws without the use of side connectors. The patients did not experience immediate postoperative complications and had stable hardware at one-month follow-up. Our cases demonstrate the surgical efficiency of robotic-assisted lumbo-iliac instrumentation which obviates the need to use a side connector, which is commonly used in iliac fixation. This eliminates a step, which can reduce the possibility of instrumentation failure. Robotic-assisted percutaneous iliac screw fixation is a safe and feasible technique to improve operative and clinical outcomes in complex spinal instrumentation surgeries.

Present and Future Spinal Robotic and Enabling Technologies.

Enabling technologies include surgical planning software, computer-assisted navigation, intraoperative three-dimensional (3D) imaging, and robotic systems. Presently, these technologies are in various stages of refinement. Spinal robots in particular are currently limited to the positioning of an alignment guide for pedicle screw placement. Current generation spinal robots, therefore, play a more limited role in spinal surgery. In contrast to spinal robots, intraoperative imaging technology has been developed further, to a stage that allows accurate 3D spinal image acquisition that can be readily utilized for spinal navigation. The integration of these various technologies has the potential to maximize the safety, consistency, reliability, and efficacy of surgical procedures. To that end, the trend for manufacturers is to incorporate various enabling technologies into the spinal robotic systems. In the near-term, it is expected that integration of more advanced planning software and navigation will result in wider applicability and value. In the long-term, there are a variety of enabling technologies such as augmented reality that may be a component of spinal robots. This article reviews the features of currently available spinal robots and discusses the likely future advancements of robotic platforms in the near- and long-term.

Computerized Tomographic Based Study of Thoracic Spine Morphology in Relevance to Pedicle Screw Fixation in Pakistani Population

Objective: To study the thoracic spine anatomy for accurate placement of pedicle screws using computerized tomography.&#x0D; Material and Methods: CT scans of 200 patients were included in our study. T1 to T12 vertebrae morphology was studied for each patient. Following measurements were taken, 1: Transverse pedicle width, 2 = Depth of anterior cortex along pedicle axis, 3 = Transverse pedicle angle, 4 = canal dimensions, 5 = vertebral body height anterior and posterior, 6 = mid vertebral body width.&#x0D; Results: Transverse pedicle width decreased from T1 (4.06 ± 0.50 mm) to T4 (3.72 ± 0.17 mm) and then gradually increases to T12 (6.08 ± 0.60 mm). Depth of the anterior vertebral cortex remained constant from T1 to T4 and gradually increases up to T12. Transverse pedicle angle remained constant from T1 to T4 with a maximum at T4 (23.39 ± 3.15 mm) and then gradually decreased to T12 (3.99 ± 2.16 mm). Anteroposterior (AP) canal dimensions were minimum at T7 (17.03 ± 1.01 mm) and maximum at T2 (21.2 ± 1.07 mm). Interpedicular (IPD) canal dimensions were minimum at T6 (19.18 ± 1.6 mm) and maximum at T3 (23.18 ± 1.2 mm). Anterior vertebral body height was minimum at T1 (16.9 ± 1.34 mm) and maximum at T12 (27.14 ± 1.34mm). Posterior vertebral body height was minimum at T1 (18.8 ± 1.13 mm) and maximum at T12 (29.76 ± 1.43 mm).&#x0D; Conclusion: A detailed anatomy of the thoracic spine is essential for surgical planning to decrease postoperative complications.

Framed and non-framed robotics in neurosurgery: A 10-year single-center experience.

Safety, efficacy and efficiency of neurosurgical robots are defined by their design (i.e., framed and non-framed) and procedural workflow (PW) (from image to surgery). The present study describes the quality indicators of three different robots in brain and spine surgery. This single-centre study enrolled 252 patients over a 10-year period. Safety (complication rate) and efficacy (diagnostic yield, pedicle screw placement) were determined. Predictors of workflow efficiency (e.g., skin-to-skin) were evaluated and compared to conventional techniques (neuronavigation, stereotaxy). All robots showed excellent reliability (97.5%-100%) with low complication rates (4.5%-5.3%) and high efficacy (94.7%-97.7%). Robotics demonstrated a better time-efficiency than neuronavigation. However, there was no shortening of surgery time compared to conventional stereotaxy. Time-efficiency differed significantly between framed and non-framed workflows. While all neurosurgical robots were reliable, safe and efficacious, there were significant differences in time-efficiency. PWs should be improved to increase the acceptance of robotics in neurosurgery.

PMD18 Reduction in Pedicle SCREW Placement Time with a Guidewireless Pedicle SCREW System for Minimally Invasive SPINE Surgery

Minimally invasive surgical (MIS) approaches in spinal surgery are considered to have less perioperative blood loss and shorter duration of hospitalization compared to open procedures. However, steeper learning curves, higher technical demand, longer operating times and fluoroscopy exposure are common challenges. The VIPER PRIME™ System was designed to mitigate these challenges by introducing the first pedicle screw placement system with a screw tip design and stylet that obviates the need for pedicle preparation.

Evaluation of K-wireless robotic and navigation assisted pedicle screw placement in adult degenerative spinal surgery: learning curve and technical notes.

K-wireless robotic pedicle screw instrumentation with navigation is a new technology with large potential. Barriers to adoption are added registration time with robotic-navigated system and reliable screw positioning. Understanding the learning curve and limitations is crucial for successful implementation. The purpose of this study was to describe a learning curve of k-wireless robotic assisted pedicle screw placement with navigation and compare to conventional techniques. A retrospective review of prospectively collected data of 65 consecutive adult patients underwent robotic-navigated posterior spinal fusion by a single spine surgeon. Registration, screw placement, and positioning times were recorded. All patients underwent intra-operative 3D fluoroscopy and screw trajectory was compared to pre-operative CT. A total of 364 instrumented pedicles were planned robotically, 311 (85.4%) were placed robotically; 17 screws (4.7%) converted to k-wire, 21 (5.8%) converted to freehand, and 15 (4.1%) planned freehand. Of the 311 robotically placed pedicle screws, three dimensional fluoroscopic imaging showed 291 (93.5%) to be GRS Grade A in the axial plane (fully contained within the pedicle) and 281 (90.4%) were GRS Grade A in the sagittal plane. All breached screw deviations from plan were identified on 3D fluoroscopy during surgery and repositioned and confirmed by additional 3d fluoroscopy scan. Reasons for conversion included morphology of starting point (n=18), soft tissue pressure (n=9), hypoplastic pedicles (n=6), obstructive reference pin placement (n=2), and robotic arm issues (n=1). Seventeen (5.5%) critical breaches (≥2-4 mm) were recorded in 11 patients, 9 (2.9%) critical breaches were due to soft tissue pressure causing skive. Two patients experienced 6 (1.9%) critical breaches from hypoplastic pedicles, and 3 (0.9%) unplanned lateral breaches were found in another patient. One patient (0.3%) experienced skive due to morphology and spinal instability from isthmic spondylolisthesis. Imaging showed 143 screws placed medially to plan (1.2±0.9 mm), 170 lateral (1.2±1.1 mm), 193 screws caudal (1.0±0.6 mm) and 117 cranial (0.6±0.5 mm). No adverse clinical sequelae occurred from implantation of any screw. The learning curve showed improvement in screw times for the first several cases. Understanding the learning curve and situations where the robotic technique may be suboptimal can help guide the surgeon safe and effectively for adoption, as well as further refine these technologies.

Application and Evaluation of an Independent Robotic Arm System in K-wire Placement for Lumbar Fusion.

A single-center randomized controlled study. The objective of this study was to introduce a novel robotic system with an independent arm ("Orthbot Intelligent Orthopedic Minimally Invasive System"; Xin Junte Surgical Technologies) that has been developed and tested as a surgical assistant for autoplacement of the Kirschner wire (K-wire) in lumbar fusion, and to evaluate its accuracy by comparing it with the conventional free-hand instrumentation. Robotic technology has performed excellently in spine surgeries and has demonstrated high clinical value and potential. Robot-assisted spinal surgery is now being promoted as a paradigm for technology-led advancement. A total of 24 patients were recruited and assigned randomly to the robotic arm group (RG) or the free-hand group (FG). Deviation distance and deviation angle (DA) of K-wire placement were measured and compared between the RG and the FG. The average deviation distance was 0.88±0.08 mm in the RG and 5.13±1.68 mm in the FG (P<0.001). In both coronal and sagittal radiographs, the average DA of K-wire placement was smaller in the RG (P<0.05), and in both axial and sagittal computed tomography scans, the average DA of pedicle screw placement was also lower in the RG (P<0.05), which indicated higher accuracy of the robotic system. The novel robotic system in this study has shown certain advantages over the conventional free-hand approach in K-wire placement for lumbar fusion, including being more accurate in K-wire placement, fully automatic, and more adaptive to preoperative plans. Although the robotic arm proves to be promising in our results, the small sample size in this clinical study necessitates further multicenter, large sample follow-up studies to verify its advantages.

Comparison of outcome between percutaneous pedicle screw fixation and the Mini-Open Wiltse Approach with pedicle screw fixation for neurologically intact thoracolumbar fractures: A retrospective study

BackgroundThe purpose of this study was to compare the outcome between percutaneous pedicle screw fixation (PPSF) and the mini-open Wiltse approach with pedicle screw fixation (MWPSF) for neurologically intact thoracolumbar fractures. MethodsFrom January 2017 to January 2019, ninety-four patients with neurologically intact thoracolumbar fractures were included in this study. In this retrospective study, forty-nine patients were operated with the PPSF and forty-five patients received MWPSF. The clinical information, surgery-related results and radiographic outcome were collected and compared between the two groups. ResultsThere was no significant difference between the two groups in total length of incisions, blood loss, post-operative hospitalization time, visual analog scale (VAS) score and Oswestry disability index (ODI) score. There was also no significant difference in the accuracy rate of pedicle screw placement between two groups; however, the facet joint violation (FJV) was significantly higher in the PPSF group. The atrophic area of multifidus muscle in the PPSF group is significantly larger than that in the MWPSF group and the operative time of MWPSF group was shorter than that in the PPSF group. Meanwhile, the PPSF group obtaining significantly more cumulative exposure to radiation (p < 0.001). The result of vertebral body angle (VBA), Cobb's angle and AVH rate in the MWPSF group were significantly better than those in the PPSF group at the last post-operative follow-up. ConclusionsBoth minimally invasive treatment techniques (PPSF and MWPSF) are safe and effective in treatment of neurologically intact thoracolumbar fractures. Nevertheless, our results indicate that MWPSF may be a better choice for neurologically intact thoracolumbar fractures, since it protects multifidus muscle, and decreases facet joint violation, operation time, as well as radiation exposure. In addition, MWPSF was associated with better reduction of kyphosis.

Using the lamina nutrient foramen as the entry point for posterior cervical pedicle screw placement

Study designA prospective study and technique description. ObjectiveThis study introduced a method for posterior cervical pedicle screw placement by using the bilateral posterior lamina nutrient foramens as the entry point. MethodsFirstly, 30 dry C3-C7 vertebrae specimens were harvested for measurement. The lamina nutrient foramens were used as the entry points for posterior cervical pedicle screw placement and four linear and two angle parameters were obtained from a computed tomography scan(CT). Then, 60 patients who underwent C3–C7 pedicle screw fixation using this method were included, linear and angle parameters were obtained from a postoperative CT. ResultsThe average incidences of lamina nutrient foramen on the C3–C7 specimens were 88.3%, 90.0%, 95.0%, 95.0%, and 96.7%, respectively. The distances from the entry point to the pedicle screw tip (OD), the pedicle transverse angles (α), and the pedicle sagittal angles (β) measure for the entry points from C3–C7 were 28.74 ± 3.45–30.15 ± 2.01 mm, 26.88 ± 6.89° to 32.72 ± 5.91°, and 12.48 ± 9.31° to 19.71 ± 8.45°, respectively, with no significant differences between the left and right sides. In the 60 patients who underwent surgery, the lengths of the pedicle screws (PL) were 28.34 ± 2.25–30.15 ± 2.31 mm, the pedicle transverse angles (α) were 26.89 ± 6.86° to 32.36 ± 5.65°, and the pedicle sagittal angles (β) were 12.49 ± 9.11° to 20.06 ± 8.91°. The new method had a 96.8% (454/469) success rate among these patients, with no screws penetrating the spinal canal or signs of vertebral artery injury. ConclusionEntry at the bilateral lamina nutrient foramen represents an alternative posterior cervical pedicle screw placement technique that is feasible and safe.

A Prospective Comparison of the Effects of Instrument Tracking on Time and Radiation During Minimally Invasive Lumbar Interbody Fusion

Minimally invasive surgical techniques have resulted in improved patient outcomes. One drawback has been the increased reliance on fluoroscopy and subsequent exposure to ionizing radiation. We have previously shown the efficacy of a novel instrument tracking system in cadaveric and preliminary clinical studies for commonplace orthopedic and spine procedures. In the present study, we examined the radiation and operative time using a novel instrument tracking system compared with standard C-arm fluoroscopy for patients undergoing minimally invasive lumbar fusion. The radiation emitted, number of radiographs taken, and time required to complete 2 tasks were recorded between the instrument tracking systems and conventional C-arm fluoroscopy. The studied tasks included placement of the initial dilator through Kambin's triangle during percutaneous lumbar interbody fusion and placement of pedicle screws during both percutaneous lumbar interbody fusion and minimally invasive transforaminal lumbar interbody fusion with or without instrument tracking. A total of 23 patients were included in the analysis encompassing 31 total levels. For the task of placing the initial dilator into Kambin's triangle, an average of 4.21 minutes (2.4 vs. 6.6 minutes; P= 0.002), 15 fluoroscopic images (5.4 vs. 20.5; P= 0.002), and 8.14 mGy (3.3 vs. 11.4; P= 0.011) were saved by instrument tracking. For pedicle screw insertion, an average of 5.69 minutes (3.97 vs. 9.67; P < 0.001), 14 radiographs (6.53 vs. 20.62; P < 0.001), and 7.89 mGy (2.98 vs. 10.87 mGy; P < 0.001) were saved per screw insertion. Instrument tracking, when used for minimally invasive lumbar fusion, leads to significant reductions in radiation and operative time compared with conventional fluoroscopy.

Clinical application of three-dimensional printing technique combined with thoracic pedicle screw track detector in thoracic pedicle screw placement

To investigate the clinical application of three-dimensional (3D) printing technique combined with a new type of thoracic pedicle screw track detector in thoracic pedicle screw placement. According to the characteristics of thoracic pedicle and common clinical screw placement methods, a new type of thoracic pedicle screw track detector was independently developed and designed. The clinical data of 30 patients with thoracic vertebrae related diseases who underwent posterior thoracic pedicle screw fixation between March 2017 and January 2020 were retrospectively analysed. Among them, there were 18 males and 12 females with an average age of 56.3 years (range, 32-76 years). There was 1 case of thoracic disc herniation, 4 cases of thoracic canal stenosis, 2 cases of ossification of posterior longitudinal ligament of thoracic vertebra, 16 cases of thoracic trauma, 2 cases of thoracic infection, and 5 cases of thoracic canal occupation. Three-dimensional CT of the thoracic vertebra was routinely performed preoperatively, and the model of the patient's thoracic vertebra was reconstructed and printed out. With the assistance of the model, preoperative simulation was performed with the combination of the new type thoracic pedicle screw track detector, and detected no nails after critical cortical damage. During operation, one side was randomly selected to use traditional hand screws placement (control group), and the other side was selected to use 3D printing technique combined with new type thoracic pedicle screw track detector to assist thoracic pedicle screws placement (observation group). The single screw placement time, adjustment times of single screw, and blood loss during screw placement were compared between the two groups. The accuracy of screw placement in the two groups was evaluated according to postoperative CT imaging data. The single screw placement time, adjustment times of single screw, and blood loss during screw placement in the observation group were significantly less than those in the control group ( P<0.05). Postoperative CT examination showed that the observation group had 87 screws of grade 1, 3 screws of grade 2, and the acceptable screw placement rate was 100% (90/90); the control group had 76 screws of grade 1, 2 screws of grade 2, 11 screws of grade 3, and 1 screw of grade 4, and the acceptable screw placement rate was 86.7% (78/90); showing significant difference in screw placement between the two groups ( χ 2=12.875, P=0.001). All patients were followed up 6-18 months, with an average of 11.3 months. There was no complication of vascular, nerve, spinal cord, or visceral injury, and screws or rods broken, and no patient was revised. The 3D printing technique combined with the new type of thoracic pedicle screw track detector assisted thoracic pedicle screw placement is convenient, and significantly improves the accuracy and safety of intraoperative screw placement, and overall success rate of the surgery.

A robotic system for spine surgery positioning and pedicle screw placement.

In recent years, surgeons have explored minimally invasive methods of percutaneous pedicle screw implantation which can effectively reduce human injuries. This article presents an accurate and efficient positioning method and robot system for percutaneous needle placement under c-arm fluoroscopy. A simple five degree of freedom (DOF) robot with a unique end-effector is designed to perform perspective calibration and image space registration. The principle of pedicle standard axis positioning is adopted to make the axis of the pedicle overlap with the x-ray axis of c-arm. Then the clinical operation is carried out to verify the clinical feasibility of the designed robot and positioning method. The experimental results show that a total of 26 pedicle screws were accurately implanted. The accuracy of Grade A is 96.15%. The positioning time of a single guide pin is about 154.77s, and three x-ray films need to be taken on average. The positioning accuracy is increased by using the present method. In addition, this method is simple in operation, short in operation time, low in X-ray exposure.

Power-assisted Pedicle Screw Technique Protects Against Risk of Surgeon Overuse Injury: A Comparative Electromyography Study of the Neck and Upper Extremity Muscle Groups in a Simulated Surgical Environment.

Cadaveric. The aim of this study was to quantify the amplitude and duration of surgeons' muscle exertion from pedicle cannulation to screw placement using both manual and power-assisted tools in a simulated surgical environment using surface electromyography (EMG). A survey of Scoliosis Research Society members reported rates of neck pain, rotator cuff disease, lateral epicondylitis, and cervical radiculopathy at 3 ×, 5 ×, 10 ×, and 100 × greater than the general population. The use of power-assisted tools in spine surgery to facilitate pedicle cannulation through screw placement during open posterior fixation surgery may reduce torque on the upper limb and risk of overuse injury. Pedicle preparation and screw placement was performed from T4-L5 in four cadavers by two board-certified spine surgeons using both manual and power-assisted techniques. EMG recorded muscle activity from the flexor carpi radialis, extensor carpi radialis, biceps, triceps, deltoid, upper trapezius, and neck extensors. Muscle activity was reported as a percentage of the maximum voluntary exertion of each muscle group (%MVE) and muscle exertion was linked to low- (0-20% MVE), moderate- (20%-45% MVE), high- (45%-70% MVE) and highest- (70%-100% MVE) risk of overuse injury based on literature. Use of power-assisted tools for pedicle cannulation through screw placement maintains average muscle exertion at low risk for overuse injury for every muscle group. Conversely with manual technique, the extensor carpi radialis, biceps, upper trapezius and neck extensors operate at levels of exertion that risk overuse injury for 50% to 92% of procedure time. Powerassisted tools reduce average muscle exertion of the biceps, triceps, and deltoid by upwards of 80%. Power-assisted technique protects against risk of overuse injury. Elevated muscle exertion of the extensor carpi radialis, biceps, upper trapezius, and neck extensors during manual technique directly correlate with surgeons' self-reported diagnoses of lateral epicondylitis, rotator cuff disease, and cervical myelopathy.Level of Evidence: N/A.

Application of Spinal Robotic Navigation Technology to Minimally Invasive Percutaneous Treatment of Spinal Fractures: A Clinical, Non-Randomized, Controlled Study.

ObjectiveTo introduce a new robotic navigation system that assists pedicle screw implantation and verify the accuracy and stability of the system.MethodsPedicle screw placements were performed on the thoracic vertebrae (T)9–Lumbar vertebrae (L)5 thoracolumbar vertebrae of cadavers using robotic guidance. The operative duration, puncture success, correction, and correction time were assessed. Additionally, a total of 30 thoracolumbar fractures from September 2017 until June 2019 were included in a clinical study. Two groups were evaluated: the robotic guidance group and freehand group. Both sexes were evaluated. Mean ages were 47.0 and 49.1 years, respectively, in the robotic and freehand groups. Inclusion criteria was age >18 years and a thoracolumbar fracture. Intervention was the operative treatment of thoracolumbar fractures. Outcome parameters were the operation time, intraoperative bleeding, and fluoroscopic data. The accuracy of the pedicle screw placement and screw penetration rate of the two groups were compared using intraoperative fluoroscopic axial images.ResultsThe success rate for 108 one‐time nail placements in cadavers was 88% and two‐time nail placement was 100%. Vertebral punctures at L5 took the longest to perform and achieve correction. Clinically, there were no significant differences in patients' sex, body mass index, age distribution, or intraoperative bleeding between the groups. The average X‐ray exposure time for patients and operators were 37.69 ± 9.24 s and 0 s in the robotic group (significantly lower than in the freehand group: 81.24 ± 6.97 s vs 56.29 ± 7.93 s, respectively). Success rates for one‐time screw placements were 98.64 and 88.46% in the robotic and freehand groups, respectively, which is significant. Screw penetration rates (1.36% vs 11.54%, robotic vs freehand), were significantly different.ConclusionsThe robotic system improved the accuracy and safety of pedicle screw internal fixation and reduced patients' and operators' intraoperative radiation exposure.