Accurate Pedicle Screw Research Articles

Selective application of navigation templates in idiopathic scoliosis: technical and hronometric features

Objective. To evaluate short-term result of selective navigation templates application in idiopathic scoliosis surgery.Material and Methods. A total of 12 patients aged 14–17 years with idiopathic scoliosis were included in the study. Group A included 6 patients treated with selective application of navigation templates for pedicle screws insertion in the most difficult zones. Group B (control) included 6 patients in whom all the pedicle screws were placed with free-hand technique. Number of screws inserted was 16–20 per patient. There was no significant difference between the groups in sex, age, Cobb angle, number of vertebrae instrumented, number of pedicle screws and laminar hooks. Surgery duration, blood loss, absolute and relative correction were compared. In Group A, duration of the 3D-objects fabrication and printing, as well as pedicle screw accuracy based on 2-mm increment grading system were evaluated.Results. Selective application of navigation templates as compared with total free hand screws placement significantly reduced surgery duration. Difference in blood loss and deformity correction was not significant. A total of 107 pedicle screws were placed in Group A, 48 of them with navigation templates and 59 by free-hand technique. Average pedicle width in screw installation with navigation templates was 4.28 ± 1.43 mm, and in that with free-hand technique 6.53 ± 1.72 mm, with significant difference. Accurate screw placement with navigation templates and by free-hand technique were 93.7 % and 88.0 %, respectively, with no significant difference. Duration of 3D-objects manufacturing was 1419 ± 190 minutes. Active operator’s involvement was required in about 10 % of the while.Conclusion. Selective application of a pair of two-level navigation templates for most difficult pedicles in idiopathic scoliosis significantly reduces surgery duration. Difference in blood loss and deformity correction is insignificant. Refusal of total templates usage for combination of navigation templates for selected difficult pedicles and free-hand technique for the rest is an option for shortening the preoperative preparation, but provides screw placement accuracy comparable with total templates usage (92.5–97.6 % as reported).

Patient-Specific Drill Guide Template for Pedicle Screw Insertion into the Atlantoaxial Cervical Spine Using Stereolithographic Modeling: An In Vitro Study.

Cadaveric study. This study aimed to assess the accuracy and feasibility of cervical pedicle screw (CPS) insertion into the atlantoaxial cervical spine using a patient-specific drill guide template constructed from a stereolithographic model. CPS fixation is a widely accepted procedure for posterior cervical fixation because of its biomechanical advantages, particularly in the subaxial cervical region. The extremely narrow corridors of the atlantoaxial spine make CPS insertion more difficult, requiring the development of new tools to ensure accurate placement. Fifteen atlantoaxial cervical vertebra specimens from 15 cadavers were scanned into thin slices using computed tomography. Images of the cadaver spine were digitally processed and rendered stl files so that they could be printed to scale as threedimensional (3D) plastic models. Manually molded dental acrylic drill guide templates with pins inserted in the pedicles of the plastic cervical models were placed over the 3D printed models. The drill guide templates were used for precise placement of the drill holes in the pedicles of cadaveric specimens for pedicle screw fixation. The accuracy of screw placement was evaluated by an independent evaluator. A total of 60 pedicles (combined C1 and C2) from 15 cadaveric axial cervical vertebrae were evaluated. The total acceptable accuracy for pedicle screw insertion in the atlantoaxial cervical vertebrae is 95%. An accuracy rate of 100% was achieved for C1 while an acceptable accuracy rate of 90% was achieved for C2. The use of a patient-specific drill guide constructed using stereolithography improved the accuracy of CPS placement in a cadaveric model.

Navigation accuracy and assessability of carbon fiber-reinforced PEEK instrumentation with multimodal intraoperative imaging in spinal oncology

Radiolucent carbon-fiber reinforced PEEK (CFRP) implants have helped improve oncological follow-up and radiation therapy. Here, we investigated the performance of 3D intraoperative imaging and navigation systems for instrumentation and precision assessment of CFRP pedicle screws across the thoraco-lumbar spine. Thirty-three patients with spinal tumors underwent navigated CFRP instrumentation with intraoperative CT (iCT), robotic cone-beam CT (rCBCT) or cone-beam CT (CBCT) imaging. Two different navigation systems were used for iCT-/rCBCT- and CBCT-based navigation. Demographic, clinical and outcome data was assessed. Four blinded observers rated image quality, assessability and accuracy of CFRP pedicle screws. Inter-observer reliability was determined with Fleiss` Kappa analysis. Between 2018 and 2021, 243 CFRP screws were implanted (iCT:93, rCBCT: 99, CBCT: 51), of which 13 were non-assessable (iCT: 1, rCBCT: 9, CBCT: 3; *p = 0.0475; iCT vs. rCBCT). Navigation accuracy was highest using iCT (74%), followed by rCBCT (69%) and CBCT (49%) (*p = 0.0064; iCT vs. CBCT and rCBCT vs. CBCT). All observers rated iCT image quality higher than rCBCT/CBCT image quality (*p < 0.01) but relevant pedicle breaches were reliably identified with substantial agreement between all observers regardless of the imaging modality. Navigation accuracy for CFRP pedicle screws was considerably lower than expected from reports on titanium implants and CT may be best for reliable assessment of CFRP materials.

P141. Robotics versus navigation for minimally invasive elective lumbar fusion

P141. Robotics versus navigation for minimally invasive elective lumbar fusion

P143. The “V” sign: a reliable anatomic and radiographic landmark for posterior percutaneous S1 screw placement

P143. The “V” sign: a reliable anatomic and radiographic landmark for posterior percutaneous S1 screw placement

P105. Intraoperative CT based pedicle screw navigation in pediatric spine deformity increases operative time, radiation exposure with minimal impact on screw accuracy for experienced surgeon

P105. Intraoperative CT based pedicle screw navigation in pediatric spine deformity increases operative time, radiation exposure with minimal impact on screw accuracy for experienced surgeon

P119. Are biplanar projection radiographs sufficient to confirm intraoperative pedicle screw placement?

<h3>BACKGROUND CONTEXT</h3> Two-dimensional BPR (AP and lateral fluoroscopy or x-ray) has been the gold standard in spine fusion surgery for many years, however, 3D intraoperative imaging systems are now available. When utilizing BPR for pedicle screw confirmation, significant misplacement rates have been reported in the lumbar and thoracic spine. <h3>PURPOSE</h3> Biplanar projection radiographs (BPR) for confirmation of intraoperative pedicle screw placement are inferior to three-dimensional fluoroscopic (3D) imaging. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of prospectively collected data. <h3>PATIENT SAMPLE</h3> A total of 100 patients underwent degenerative spinal surgery by one spine surgeon. <h3>OUTCOME MEASURES</h3> Screw placement was compared between postoperative CT, intraoperative x-rays( BPR) and intraoperative 3D fluoroscopic imaging. <h3>METHODS</h3> One hundred patients underwent degenerative spinal surgery by one spine surgeon and screw placement was compared from preoperative CT images to intraoperative 3D fluoroscopy. The M-line and Gertzbein-Robbins system (GRS) was used to confirm false positives or negatives in BPR. M-line was defined as a line connecting the upper and lower spinous processes through the fixed vertebrae within BPR. GRS measures pedicle screw accuracy and categorizes positions into 4 groups based on a clinical positioning grading used in 3D imaging. <h3>RESULTS</h3> A total of 604 instrumented pedicles in 100 patients were planned robotically, 497 (82.2%) were placed robotically. Each patient received a postoperative CT, intraoperative X-rays (BPR), and intraoperative 3D fluoroscopic imaging. M-Lines were measured for each patient vias intraoperative X-ray postoperatively. Patient postoperative CTs were compared to intraoperative 3D fluoroscopy by the GRS method. Postoperative CTs were then compared to M-line findings in BPR, to confirm whether false positives or negatives were detected. Based on BPR imaging, 5 (5%) patients exhibited 5 (0.8%) screws which were all robotically placed screws crossing the M-line in BPR. However, when compared to their postoperative CT imaging, breach was not detected and was classified as fully within the pedicle (category A of GRS). A BPR in a separate patient (1%) did exhibit one screw (0.2%) with a false negative BPR compared to 3D imaging. This could be possibly due to anatomical rotation in BPR. <h3>CONCLUSIONS</h3> A clinically significant number of patients had false-negative and false-positive screw confirmation on BPR. In 5% of patients and 0.8% of screws, a false-negative breaching within robotically placed screws was seen. Furthermore, 1% of patients and 0.2% of screws showed a false negative of pedicle screw mal-positioning. BPR may yield a false sense of security for misplaced screws and conversely may raise concern over screws that are in a satisfactory position. These findings may make 3D imaging a more desirable post-instrumentation gold standard. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

216. The arrival of augmented reality in MIS: initial results of use for percutaneous pedicle screw instrumentation

<h3>BACKGROUND CONTEXT</h3> Augmented reality (AR) employs computer-generated sensory inputs to enhance the user's perception of his or her environment. Pedicle screw instrumentation has become a mainstay of spinal stabilization. In general, pedicle screw accuracy rates have improved with increasing use of technology; navigation-based instrumentation have been described as accurate in 89-100% of cases. Some inherent difficulties persist with regards to ergonomics and efficiency of spinal navigation. Traditional navigation requires removing focus from the surgical field to interpret and coordinate input of external visual data. Line-of-sight disturbance and attention-shift has known impact on cognitive load and optimization of workflow in surgery. Emerging AR technology in spine surgery aims to reduce the impact of these pitfalls. <h3>PURPOSE</h3> To describe the first known series of in vivo pedicle screws placed percutaneously using AR technology for minimally invasive surgery (MIS) applications. <h3>STUDY DESIGN/SETTING</h3> After IRB approval, three senior surgeons at two institutions collected cases from June, 2020 - October, 2021, in which AR was used for placement of percutaneous pedicle screw instrumentation. <h3>PATIENT SAMPLE</h3> A total of 148 total MIS cases were studied; the average patient age was 59.7 ±13.84 and average BMI was 30.8 ±7.2. <h3>OUTCOME MEASURES</h3> Patient demographics and surgical metrics including total posterior construct time (defined as time elapsed from pre-incision instrument registration, percutaneous posterior fusion and final screw placement) were recorded. Screw revision intraoperatively after fluoroscopic evaluation and revision rates postoperatively were recorded. <h3>METHODS</h3> The xvision^TM (Augmedics Inc., Arlington Heights, IL, USA) system features a wireless headset with transparent near-eye display which projects intraoperative 3D imaging directly onto the surgeon's retina. After patient positioning, one percuntaneous and one superficial reference marker are placed. Intra-operative CT data is processed to the headset and integrates into the surgeon's visual field creating a "see-through" 3D effect in addition to 2D standard navigation images. MIS pedicle screw placement is then carried out percutaneously through single line of sight using navigated instruments. <h3>RESULTS</h3> Of the 148 cases, 139 (93.9%) were performed for degenerative pathology, 6 (4.1%) for tumor and 3 (2.0%) for spinal deformity. A total of 535 pedicle screws were placed; 519 (97.0%) lumbar and 16 (3.0%) thoracic. Eighty-four (58.8%) cases were 1-level, 42 (28.4%) were 2-level, 16 (10.8%) were 3-level and 6 (4.1%) were 4-level, equating to an average of 3.51 screws per case. A total of one screw (0.20%) was replaced intraoperatively after examining position with fluoroscopy. No instrumentation was revised postoperatively at final available follow-up ranging from 3-18 months. The mean total posterior construct time was 5 minutes and 56 seconds per screw overall; cases later in the learning curve achieved total posterior construct mean time of 2 minutes and 51 seconds per screw. <h3>CONCLUSIONS</h3> This study represents the first report of the use of AR to place MIS pedicle screws. These data support an exceedingly low rate of complications with screw placement and confirms a rapid learning curve with a high level of surgical efficiency demonstrated. These advances are achieved with an image- and implant-agnostic system which requires no physical footprint in the operating room. <h3>FDA DEVICE/DRUG STATUS</h3> xvision^TM (Augmedics Inc., Arlington Heights, IL, USA) (Approved for this indication)

89. Comparison of pedicle screw accuracy using two different robotic techniques: a matched cohort study

BACKGROUND CONTEXT Adoption of robotic technology in spine fusion surgery has expanded significantly in recent years, yet several different techniques exist. Robotic spine surgery allows trajectory guidance and combined navigation allows real-time visualization of instrument/screw placement. Instrumentation of the pedicle can be performed through the robotic arm using anti-skive pin (ASP) or navigated high-speed drill (NHSD). PURPOSE The NHSD may show a decrease in the incidence of skive compared to ASP. STUDY DESIGN/SETTING Matched cohort series. PATIENT SAMPLE This study included 117 patients. OUTCOME MEASURES Screw placement was compared between two groups and incidence of skive compared to ASP. METHODS A total of 737 screws were placed in 117 patients and measurements were recorded. Screw placement was compared in the control group ASP (n=65) and the study group NHSD (n=52). RESULTS Of 117 patients, 65 in the ASP control group had 364 instrumented pedicles and 311 (85.4%) placed robotically. The NHSD study group consisted of 52 patients with 373 instrumented pedicles and 352 (94.4 %) placed robotically. In the control group, a drill guide was placed down the outer cannula, an ASP was manually tapped into the pedicle, then the drill guide tapped into the bone with an outer cannula before drilling into the pedicle under navigation. In the study group, four instruments combined into one and were implemented with NHSD into the pedicle in a single step without additional cannulas or pins. A significant decrease in the number of cases with skive and the total skived screws was found between groups. The control group reported skive in 17% of patients (11/65) which corresponded to 4.7% of screws robotically placed (17/311). The study group reported 1 (1.9%) case with only 2 (0.5%) screws that skived (same as above). Skive occurred in fewer patients with NSHD (p=.002) and in fewer of the NSHD placed screws (p=.014). CONCLUSIONS Pedicle instrumentation with NHSDs shows a decrease in the incidence of skive compared to an ASP. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Adoption of robotic technology in spine fusion surgery has expanded significantly in recent years, yet several different techniques exist. Robotic spine surgery allows trajectory guidance and combined navigation allows real-time visualization of instrument/screw placement. Instrumentation of the pedicle can be performed through the robotic arm using anti-skive pin (ASP) or navigated high-speed drill (NHSD). The NHSD may show a decrease in the incidence of skive compared to ASP. Matched cohort series. This study included 117 patients. Screw placement was compared between two groups and incidence of skive compared to ASP. A total of 737 screws were placed in 117 patients and measurements were recorded. Screw placement was compared in the control group ASP (n=65) and the study group NHSD (n=52). Of 117 patients, 65 in the ASP control group had 364 instrumented pedicles and 311 (85.4%) placed robotically. The NHSD study group consisted of 52 patients with 373 instrumented pedicles and 352 (94.4 %) placed robotically. In the control group, a drill guide was placed down the outer cannula, an ASP was manually tapped into the pedicle, then the drill guide tapped into the bone with an outer cannula before drilling into the pedicle under navigation. In the study group, four instruments combined into one and were implemented with NHSD into the pedicle in a single step without additional cannulas or pins. A significant decrease in the number of cases with skive and the total skived screws was found between groups. The control group reported skive in 17% of patients (11/65) which corresponded to 4.7% of screws robotically placed (17/311). The study group reported 1 (1.9%) case with only 2 (0.5%) screws that skived (same as above). Skive occurred in fewer patients with NSHD (p=.002) and in fewer of the NSHD placed screws (p=.014). Pedicle instrumentation with NHSDs shows a decrease in the incidence of skive compared to an ASP.

P120. Augmented reality navigation for percutaneous thoracolumbar pedicle screws: a prospective clinical study

<h3>BACKGROUND CONTEXT</h3> Conventional navigation systems depend on a separate imaging system and use of passive infra-red cameras with a bulky dynamic reference frame (DRF) attached to the spine and to the instruments for live tracking. This often leads to 1) issues with line of sight 2) need for an invasive procedure to attach the DRF 3) lowered accuracy due to inadvertent bumping of the DRF and when point of interest is further from the location of the DRF and 4) a need for repeated re-registrations that can affect the surgical workflow and impact the procedure time. These common issues that impede the adoption of navigation can be bypassed using an Augmented Reality Surgical Navigation system (ARSN), that combines the use of superior quality 3D intra-operative imaging and optical camera based Augmented Reality Navigation (ARN), noninvasive dynamic patient monitoring and on-shaft optical trackers on the Jamshidi needles to provide real time visual feedback of instrument location, without relying on fluoroscopy. <h3>PURPOSE</h3> To determine the accuracy of percutaneous pedicle screw placement when using ARSN. <h3>STUDY DESIGN/SETTING</h3> A single-arm, prospective multicenter clinical study. <h3>PATIENT SAMPLE</h3> A total of 211 pedicle screws were placed percutaneously in 39 patients between levels T2 and S1. The predominant indication was trauma (42%). However, patients with instability of the spine due to degenerative and neoplastic diseases were also included. <h3>OUTCOME MEASURES</h3> Accuracy of pedicle screw placement according to Gertzbein grading (Grade 0: no breach; Grade 1: 4mm breach) determined by three independent reviewers. The median time required to insert the pedicle screw in the right location when using the system was also noted. <h3>METHODS</h3> Navigation was performed in a hybrid OR including surgical table, motorized flat detector C-arm with intraoperative 2D/3D imaging capabilities, optical video cameras integrated in the detector for ARN, and patient motion tracking using skin markers. The C-arm rotated 180 degrees in 10 seconds during acquisition, creating a 3D Cone-Beam CT (CBCT) of the area of interest of 4-8 levels. A disposable Jamshidi needle with optical markers etched on the shaft was used to guide the needle to the desired location in the vertebral body using ARN. <h3>RESULTS</h3> Overall accuracy (Gertzbein 0-1) was 98.1% (95% CI 95.2-99.5). For thoracic screws (n=69), accuracy was 95.7%, for lumbar screws (n=126) 99.2%. Grade 0 screws (no breach) were 93% overall (86% in thoracic and 96% in lumbar levels). Four screws were graded as 2 (2-4 mm breach), with a medial positioning. Three of them were in the upper thoracic spine. None was associated with a neurological consequence. No screw was highly misplaced (> 4mm error). Six screws (2.7%) were intraoperatively revised. Median time per screw was 6 minutes and 25 sec (± 3.3 min). <h3>CONCLUSIONS</h3> Use of ARN leads to a high rate of accurate pedicle screw placement. The use of ARSN favorably compares to screw placement times reported in literature. <h3>FDA DEVICE/DRUG STATUS</h3> ClarifEye surgical navigation system (Philips Healthcare) (Approved for this indication)

First Clinical Experience with a Novel 3D C-Arm-Based System for Navigated Percutaneous Thoracolumbar Pedicle Screw Placement

Background and Objectives: Navigated pedicle screw placement is becoming increasingly popular, as it has been shown to reduce the rate of screw misplacement. We present our intraoperative workflow and initial experience in terms of safety, efficiency, and clinical feasibility with a novel system for a 3D C-arm cone beam computed-tomography-based navigation of thoracolumbar pedicle screws. Materials and Methods: The first 20 consecutive cases of C-arm cone beam computed-tomography-based percutaneous pedicle screw placement using a novel navigation system were included in this study. Procedural data including screw placement time and patient radiation dose were prospectively collected. Final pedicle screw accuracy was assessed using the Gertzbein–Robbins grading system. Results: In total, 156 screws were placed. The screw accuracy was 94.9%. All the pedicle breaches occurred on the lateral pedicle wall, and none caused clinical complications. On average, a time of 2:42 min was required to place a screw. The mean intraoperative patient radiation exposure was 7.46 mSv. Conclusions: In summary, the investigated combination of C-arm CBCT-based navigation proved to be easy to implement and highly reliable. It facilitates the accurate and efficient percutaneous placement of pedicle screws in the thoracolumbar spine. The careful use of intraoperative imaging maintains the intraoperative radiation exposure to the patient at a moderate level.

Alternative Uses of O-Arm and Stealth Navigation Technology Over 10 Years: The University of Colorado Experience.

Intraoperative computed tomography scanning with O-arm and use of Stealth navigation can improve surgical outcomes in a variety of orthopedic subspecialties. In spine surgery, the accuracy, precision, and safety of pedicle screw and interbody implant placement has improved. This technology is now routinely used in percutaneous pedicle screw placement and minimally invasive sacroiliac joint fusion. Other applications include, but are not limited to, isthmic pars defect repair, lumbosacral pseudoarticulation resection in Bertolotti's syndrome, radiofrequency ablation, and en bloc tumor resection. Intraoperative navigation has numerous applications, and use of this technology should continue to evolve as the technology advances. [Orthopedics. 2023;46(2):e89-e97.].

Comparison of pedicle screw placement accuracy between two types of imaging support (Artis Zeego versus two-dimensional fluoroscopy): a cross-sectional observational study

BackgroundThe pedicle screw system is widely used in spine surgery, and it provides rigid fixation and leads to successful subsequent deformity correction and bony fusion. The standard imaging technique for pedicle screw insertion is two-dimensional images obtained from C-arm-type X-ray fluoroscopy. Artis Zeego is an emerging intraoperative imaging technique that can provide conventional two-dimensional fluoroscopic images and rapid three-dimensional fluoroscopic computed tomography reconstruction imaging. The aim of this study is to compare the insertion accuracies of PS placement using Artis Zeego and conventional 2D X-ray fluoroscopy.MethodsIn this study, we retrospectively reviewed the postoperative images of thoracolumbar fusion patients who underwent surgery using pedicle screws between 2013 and 2018. Pedicle screw malplacement was assessed using a four-grade classification by Rao et al. Misplacement rates were compared between pedicle screws assisted with Artis Zeego and two-dimensional fluoroscopy.ResultsA total of 1107 pedicle screws in 153 patients were inserted using Artis Zeego, and 427 pedicle screws in 80 patients were inserted using fluoroscopy. The overall perforation rate was 4.2% (46 perforations of 1106 pedicle screws) in the Artis Zeego group and 7.7% (33 perforations of 427 pedicle screws) in the fluoroscopy group. In the Artis Zeego group, 43 (3.9%) screws were classified as grade 1, and three (0.3%) screws were classified as grade 2. In the fluoroscopy group, 21 (4.9%) screws were classified as grade 1, 10 (2.3%) screws were classified as grade 2, and 2 (0.5%) screws were classified as grade 3. The use of Artis Zeego was associated with a significantly lower screw malplacement rate than was the use of fluoroscopy (p < 0.001).ConclusionsOur results demonstrated that pedicle screw placement with Artis Zeego was associated with a lower malplacement rate than was conventional two-dimensional fluoroscopy. No severe malplacement was observed in the Artis Zeego group. Thus, Artis Zeego could be a good option for improving pedicle screw accuracy.

Application of electromagnetic navigation in endoscopic transforaminal lumbar interbody fusion: a cohort study.

Clinical retrospective cohort study. To explore the application of the electromagnetic navigation system in Endo-TLIF. From May 2019 to March 2020, 76 patients with single-segment lumbar spondylolisthesis treated by electromagnetic navigation-assisted Endo-TLIF (NE group) and conventional Endo-TLIF (CE group) were enrolled in the study. Time of pediclescrew implantation, entire operation time, the number of intraoperative X-ray fluoroscopy exposures, total blood loss, incisionlength, ambulation time, accuracy of pedicle screws, complications, visual analog scale for back and leg pain, Oswestry Disability Index, Japanese Orthopedic Association score and postoperative fusion rates were recorded, respectively. There were no significant differences in preoperative demographics between the NE and CE groups (P > 0.05). The mean number of intraoperative X-ray fluoroscopy exposures, guidewires insertion, entire operation time, total blood loss and adjustment rate of screws in the NE group were significantly less compared with the CE group (P < 0.05, respectively). There were no significant differences in clinical parameters between the two groups at different time points in the follow-up period (P > 0.05). There was no statistical difference in fusion rates between the two groups. In addition, one case of cage subsidence was observed after surgery in the CE group. Electromagnetic navigation systems could be applied throughout the entire surgical course and ameliorate theshortcomingsofthe conventional Endo-TLIF technique to reduce radiation exposure, improve accuracy, avoid repetitive operations and shorten surgery time and the required learning curve of the procedure. Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Clinical study on real-time three-dimensional CT navigation-guided full-endoscopic lumbar interbody fusion

To analyze the technical notes, effectiveness, and current issues of real-time three-dimensional CT navigation-guided full-endoscopic lumbar interbody fusion. Between April 2020 and October 2021, a total of 27 patients received real-time three-dimensional CT navigation-guided full-endoscopic lumbar interbody fusion. There were 18 males and 9 females with an average age of 63.2 years (range, 48-84 years). There were 6 cases of lumbar spinal stenosis, 1 case of lumbar instability, 9 cases of lumbar spinal stenosis with instability, 3 cases of degenerative spondylolisthesis, 6 cases of isthmus spondylolisthesis, and 2 cases of recurrent lumbar disc herniation. All patients showed neurological symptoms before operation (ipsilateral symptom for 15 cases and bilateral symptom for 12 cases). The symptom duration was 1-300 months (median, 24 months). The operations were performed via transforaminal approach in 8 cases, trans-facet joint approach in 18 cases, and combined approaches in 1 case. A total of 32 levels were fused, including 23 single-level cases, 3 two-level cases, and 1 three-level case. Lumbar fusion segment was L 2, 3 in 1 case, L 3, 4 in 4 cases, L 4, 5 in 20 cases, and L 5, S 1 in 7 cases. The operation time, intraoperative estimated blood loss (IEBL), and perioperative complications were recorded. The improvement of intervertebral space height at fusion level was measured, and the accuracy of percutaneous pedicle screw (PPS) and Cage placement was also evaluated based on CT images performed at 1 week postoperatively. Visual analogue scale (VAS) score for both low back pain and leg pain, Japanese Orthopaedic Association (JOA) score, and Oswestry disability index (ODI) were evaluated before operation, at 1 week postoperatively, and at last follow-up. Satisfaction to effectivenss were assessed by patients using modified MacNab criteria at last follow-up. The operation time was ranged from 255 to 805 minutes (mean, 424.9 minutes). IEBL was 150-290 mL (mean, 219.3 mL). All patients received follow-up with the duration from 4 to 22 months (mean, 12.4 months). At 1 week postoperatively and last follow-up, VAS scores of low back pain and leg pain, JOA score, and ODI were significantly improved when compared with those before operation ( P<0.05). At last follow-up, the clinical indicators were similar in comparison with those at 1 week postoperatively ( P>0.05). There were 26 patients and 1 patient who respectively ranked excellent and mild in terms of effectiveness according to the modified MacNab criteria, with the excellent and good rate of 96.3%. There was 1 patient who suffered from incomplete injury of L 5 nerve root and partial neurological function recovered after 3-month conservative treatments. There were 118 implanted PPSs, and 116 of them were implanted under navigation. There were 33 Cages that were implanted under navigation. The accuracy of PPS and Cage placement was 99.1% and 97.0% respectively based on CT performed at 1 week postoperatively. The postoperative intervertebral space height was significantly increased in comparison with that before operation ( P<0.05). During follow-up, mild Cage subsidence was observed in 1 patient, whereas no fixation loosing was found. Real-time three-dimensional CT navigation-guided full-endoscopic lumbar interbody fusion has great safety and effectiveness with satisfactory preliminary clinical results. Design and further improvement of surgical equipment and instruments are expected to resolve the current technical difficulties.

Accuracy and safety of percutaneous pedicle screw placement using the K-wireless minimally invasive spine percutaneous pedicle screw system in Japan: A randomized active controlled study

BackgroundMinimally invasive lumbar fusion has recently become a widely used technique worldwide. This randomized active controlled study was conducted to demonstrate the non-inferiority of the K-wireless Minimally Invasive Spine (MIS) Percutaneous Pedicle Screw (PPS) system compared with use of the six pedicle screw systems currently used in our practices with respect to the accuracy of pedicle screw placement.Also to compare the screw-insertion time and number of fluoroscopic observations during screw insertion between the groups. MethodsA total of 80 patients with degenerative spinal diseases or vertebral fractures were assigned, including 41 patients in the K-wireless MIS PPS system group (K-wireless group) and 39 in the control group (K-wire group).The accuracy of the screw insertion, screw-insertion time, number of fluoroscopic observations during screw insertion, and the incidence of adverse events were compared between the K-wireless group and the K-wire group. The accuracy rate was calculated as the number of screws with no breach divided by the total number of screws. ResultsThe accuracy rates of screw insertion were 85.7% and 75.0% in the K-wireless and K-wire groups, respectively, with an intergroup difference of 10.7% (95% confidence interval: 2.3–19.1%). The K-wireless group demonstrated non-inferiority compared with the K-wire group. The mean screw-insertion time was significantly shorter in the K-wireless group (2.62 and 2.97 min in the K-wireless and K-wire groups, respectively; P=0.005). There were also significantly fewer fluoroscopies in the K-wireless group (10.7 and 17.4 in the K-wireless and K-wire groups, respectively; P<0.001). There were no device-related or study treatment-related adverse events in either group. ConclusionsThe accuracy of pedicle screw insertion using the K-wireless MIS PPS system was not inferior to that of existing products. In terms of safety, no product-related or treatment-related adverse events were identified in this study and no new safety concerns were noted.

What's New in Spine Surgery.

What's New in Spine Surgery.

Surface Navigation and the Influence of Navigation on MIS Surgery.

Study Design:Literature review.Objectives:To review the evidence for surface-based navigation in minimally-invasive spine surgery (MIS), provide an outline for its workflow, and present a wide range of MIS case examples in which surface-based navigation may be advantageous.Methods:A comprehensive review of the literature and compilation of findings related to surface-based navigation in MIS was performed. Workflow and case examples utilizing surface-based navigation were described.Results:The nascent literature regarding surface-based intraoperative navigation (ION) in spine surgery is encouraging and initial studies have shown that surface-based navigation can allow for accurate pedicle screw placement and decreased operative time, fluoroscopy time, and radiation exposure when compared to traditional fluoroscopic imaging. Surface-based navigation may be particularly useful in MIS cervical and lumbar decompressions and MIS lumbar instrumentation cases.Conclusions:Overall, it is possible that surface-based ION will become a mainstay in the armamentarium of enabling technologies utilized by minimally-invasive spine surgeons, but further studies are needed assessing its accuracy, complications, and cost-effectiveness.

A Retrospective Comparative Analysis of Perioperative Complications in Navigated versus Conventional Thoracolumbar Fusion in the Setting of Adult Spinal Deformity

Stereotactic intraoperative computer-assisted navigation has been shown to improve pedicle screw accuracy in spinal fusion surgery, but evidence of impact of navigation on clinical outcomes is lacking. The aim of this study is to compare rates of perioperative complications between navigated and nonnavigated procedures for deformity correction. An administrative database was queried for adult patients undergoing thoracolumbar fusion procedures for deformity. Nonelective cases and those involving malignancy, infection, or trauma were excluded. Individuals were divided into 2 cohorts based on the use of stereotactic intraoperative navigation and paired 1:1 for comparison based on a propensity score matching algorithm. Rates of unplanned reoperation and other perioperative complications were compared between matched groups. A multivariable Cox regression model was constructed to identify the impact of navigation on specific subgroups. A total of 6150 patients met eligibility criteria for the study; after propensity score matching, 456 patients who underwent conventional fusion were matched to 456 patients receiving intraoperative navigation. Navigated cases took an average of 30minutes longer than nonnavigated cases. There were no significant differences in rates of complications between cohorts. A subgroup analysis revealed that use of navigation was associated with decreased hazard for reoperation in individuals undergoing interbody fusion. Despite increased surgical duration, the use of navigation does not seem to significantly impact rates of perioperative complications outside of procedures involving interbody fusion. Surgeons should elect to use navigation in cases expected to be of high operative complexity at their own discretion.

5 Cervical Spine Pedicle Screw Accuracy in Open Fluoroscopic, Navigated and Template Guided Systems- a Systematic Review

Abstract Aim Pedicle screws provide excellent fixation for a wide range of indications; their adoption in the cervical spine has been slower than in the thoracic and lumbar spine, largely due to the smaller pedicle sizes and proximity to neurovascular structures in the neck. Recent years have seen the development of technology to improve accuracy and thereby safety in cervical pedicle screw placement over traditional fluoroscopic techniques, including intraoperative 3D navigation, computer assisted systems and physical templates with screw guides. We have performed a systematic review into the accuracy rates of the various systems. Method PubMed and Cochrane Library databases were searched; keywords "pedicle screw cervical spine" were searched; 9 valid papers involving 1427 screws were found. Results Accuracy rates were 80.6% for fluoroscopy, 91.4% for navigation methods, and 96.7% for templates. Conclusions Superior results for templates are complemented by reduced radiation exposure to patient and surgeon; however, the technology requires prolonged pre-operative planning to create the bespoke template, and the development of an infrastructure to allow for their rapid production and delivery is needed before they become more widely available. Two broad methods of navigation currently exist: intraoperative CT scanning providing real-time 3D navigation and preoperative CT registration in relation to a fixed reference with intraoperative computer assistance. At present, these methods are more commonly used, due to their proven improved accuracy rates over fluoroscopy, availability in emergencies and alongside minimally invasive techniques. Despite their novelty and limitations, templates provide promising accuracy scores, although practical considerations may inhibit their proliferation.