Pedicle Screw Insertion Research Articles

Fast and versatile platform for pedicle screw insertion planning.

Computer-assisted surgical planning methods help to reduce the risks and costs in transpedicular fixation surgeries. However, most methods do not consider the speed and versatility of the planning as factors that improve its overall performance. In this work, we propose a method able to generate surgical plans in minimal time, within the required safety margins and accounting for the surgeon's personal preferences. The proposed planning module takes as input a CT image of the patient, initial-guess insertion trajectories provided by the surgeon and a reduced set of parameters, delivering optimal screw sizes and trajectories in a very reduced time frame. The planning results were validated with quantitative metrics and feedback from surgeons. The whole planning pipeline can be executed at an estimated time of less than 1min per vertebra. The surgeons remarked that the proposed trajectories remained in the safe area of the vertebra, and a Gertzbein-Robbins ranking of A or B was obtained for 95 % of them. The planning algorithm is safe and fast enough to perform in both pre-operative and intra-operative scenarios. Future steps will include the improvement of the preprocessing efficiency, as well as consideration of the spine's biomechanics and intervertebral rod constraints to improve the performance of the optimisation algorithm.

A Pilot Human Cadaveric Study on Accuracy of the Augmented Reality Surgical Navigation System for Thoracolumbar Pedicle Screw Insertion Using a New Intraoperative Rapid Registration Method.

To evaluate the feasibility and accuracy of AR-assisted pedicle screw placement using a new intraoperative rapid registration method of combining preoperative CT scanning and intraoperative C-arm 2D fluoroscopy in cadavers. Five cadavers with intact thoracolumbar spines were employed in this study. Intraoperative registration was performed using anteroposterior and lateral views of preoperative CT scanning and intraoperative 2D fluoroscopic images. Patient-specific targeting guides were used for pedicle screw placement from Th1-L5, totaling 166 screws. Instrumentation for each side was randomized (augmented reality surgical navigation (ARSN) vs. C-arm) with an equal distribution of 83 screws in each group. CT was performed to evaluate the accuracy of both techniques by assessing the screw positions and the deviations between the inserted screws and planned trajectories. Postoperative CT showed that 98.80% (82/83) screws in ARSN group and 72.29% (60/83) screws in C-arm group were within the 2-mm safe zone (p < 0.001). The mean time for instrumentation per level in ARSN group was significantly shorter than that in C-arm group (56.17 ± 3.33s vs. 99.22 ± 9.03s, p < 0.001). The overall intraoperative registration time was 17.2 ± 3.5s per segment. AR-based navigation technology can provide surgeons with accurate guidance of pedicle screw insertion and save the operation time by using the intraoperative rapid registration method of combining preoperative CT scanning and intraoperative C-arm 2D fluoroscopy.

“Satellite pedicle screws” - A novel technique of pedicle screw insertion in obese patients undergoing lumbar fusion

The presence of thick sub-cutaneous fat and bulky paraspinal musculature mandates extensive surgical dissection in obese patients undergoing open Transforaminal lumbar interbody fusion surgery. Securing a ‘converging’ pedicle screw trajectory becomes difficult by the counterforces of the erector spinae muscles and thick sub-cutaneous fat in obese patients, especially at the L5-S1 level. We describe the use of a limited standard posterior midline exposure and a separate, far lateral ‘satellite’ incision to insert pedicle screws in an optimal trajectory in obese patients. Through proper pre-operative planning of the axial and sagittal MRI, the appropriate entry site is determined which is executed intra-operatively to insert pedicle screws freehand. Through a single 1.5 cm incision, both L5-S1 screws were inserted. Fourteen obese patients (mean BMI was 30.5 ± 1.1) received 56 satellite pedicle screws for TLIF at L5-S1 level. The mean age was 48.3 ± 9.7 years. The mean blood loss was 244.8 ± 114 ml and the mean operative time was 126.7 ± 82.8 min. In all patients, the screws were inserted as per pre-operative planning without any difficulties. All wounds healed well without wound complications. There were no screw related complications, and in the antero-posterior and lateral radiographs, there were no screw breaches. Satellite free-hand pedicle screws are safe and easily reproducible. They enable limited dissection of the main surgical wound and well-medialised converging pedicle screws in obese patients.

Analysis of accuracy of pedicle screw placement in dysplastic pedicles in adolescent idiopathic scoliosis using the pedicle expansion technique with CT-based navigation

BackgroundThis study aimed to study the accuracy of pedicle screw (PS) insertion into dysplastic pedicles in adolescent idiopathic scoliosis (AIS) comparing cannulated screw using the pedicle expansion technique (PET) versus conventional technique. MethodsForty-two AIS patients with 766 PSs were evaluated. In total, 236 screws were inserted into dysplastic pedicles: 138 and 98 screws were inserted using the PET (PET group) and standard technique (conventional group), respectively. Both methods used CT-based navigation to determine the insertion point. In the PET, a rigid ball tip feeler was tapped with a mallet to create an insertion route, a guide wire was passed through the tap, the pedicle was enlarged, and then a cannulated PS with a diameter of 4.35 mm was inserted. Postoperative CT was used to compare the accuracy of PS insertion. ResultsIn total, 23/236 (9.7%) perforations occurred. Regarding overall perforation, there were six (4.3%) and 17 (17.3%) cases in the PET and conventional group, respectively (P = 0.008). In terms of medial perforation, the PET group (n = 2, 1.4%) was significantly better than the conventional group (n = 7, 7.1%) (P = 0.021). In terms of lateral perforation, the PET group (n = 4, 2.9%) was significantly better than conventional group (n = 10, 10.2%) (P = 0.030). Only grade 1 perforation had occurred in the PET group, whereas grades 2 and 3 perforation occurred in the conventional group. ConclusionUse of the PET with CT-based navigation significantly increased the accuracy and safety of PS insertion in dysplastic pedicles in AIS.

437 Percutaneous Juxtapedicular Cement Salvage of Failed Pedicle Screws: A Cadaveric Biomechanical Study

INTRODUCTION: Posterior spinal fixation with pedicle screw-based constructs is the gold standard for stabilizing the thoracolumbar spine; however, these constructs sometimes fail due to fatigue loading, necessitating revision surgery. A common hardware revision strategy involves open surgery for screw upsizing, with or without cement augmentation, and extension of fusion. Others have described good clinical outcomes following percutaneous juxtapedicular cement salvage of failing pedicle screws. The relative biomechanical properties of these various approaches has not been evaluated. METHODS: Thirty-two fresh, un-embalmed vertebrae from four cadaveric thoracolumbar spines were used for the study. The study was conducted in two phases. The first phase involved primary pedicle screw insertions and pullout strength testing to model critical pedicle screw failure. The second phase involved revision of failed pedicle screws followed by pullout testing. The four revision cohorts were: 1) Screw Upsizing, 2) Vertebroplasty (cement augmentation with replacement of primary screw), 3) Fenestrated Screws with cement augmentation, and 4) Juxtapedicular Cement Salvage. RESULTS: There was no statistically significant difference in primary fixation strength between the cohorts. The Screw Upsizing cohort exhibited inferior pullout strength compared to the other groups which involved cement augmentation. There was no significant difference in pullout strength between Vertebroplasty, Fenestrated Screws, or Juxtapedicular Cement Salvage cohorts. CONCLUSIONS: Cement augmentation confers superior pullout strength compared to screw upsizing only. The key finding of this study is that the technique of percutaneous juxtapedicular cement salvage is biomechanically non-inferior to other revision strategies that require an open procedure to perform.

Morphology analysis of the C2 pediculoisthmic component and feasibility of safe C2 pedicle screw placement: comparison of multiplanar reconstruction versus traditional radiographic methods

BackgroundPreoperatively evaluating the feasibility of safe C2 pedicle screw placement is the key to avoiding iatrogenic vertebral artery injury. However, it has not been verified whether the conventional CT measurements of C2 pediculoisthmic component (PIC) are reliable and accurate, and the results may lack validity. The purpose of this study is to analyze the evaluative performance of conventional CT measurements and to create an accurate predictor of morphometrics of C2 PIC.MethodsA total of 304 C2 PICs were measured in 152 consecutive patients who underwent CT examination of the cervical spine between April 2020 and December 2020. We obtained the morphometric parameters of C2 PIC by measuring minimum PIC diameter (MPD) in CT multiplanar reconstruction versus conventional measurements of transverse PIC width (TPW), oblique PIC width (OPW) and definition of high-riding vertebral artery (HRVA). The outer diameter measured less than 4 mm in MPD was regarded as the standard of precluding safe C2 pedicle screw insertion. The evaluative performance of the conventional CT measurements was assessed, and the correlation between conventional CT measurements and measurements in CT multiplanar reconstruction was calculated.ResultsThe parameters in OPW and MPD were measured significantly larger than those in TPW, and the preclusion of C2 pedicle screw placement evaluated from TPW and HRVA was significantly higher than that evaluated from OPW and MPD. The sensitivity of TPW was 93.09%, and the specificity was 79.31%. The sensitivity and specificity of OPW were 97.82% and 82.76%. The sensitivity of HRVA was 88.36%, and the specificity was 96.55%. Strong agreement with the highest correlation coefficient (0.879) and determination coefficient (0.7720) suggested that the outer diameter of OPW could be useful for the precise prediction of MPD.ConclusionsCT MPR allows accurate measurement of the narrowest section of the C2 PIC. The outer diameter of OPW could be simply measured and be useful for precise prediction of MPD, which makes C2 pedicle screw placement more safely than the conventional measurement of TPW and HRVA.

Accuracies of various types of spinal robot in robot-assisted pedicle screw insertion: a Bayesian network meta-analysis

BackgroundWith the popularization of robot-assisted spinal surgeries, it is still uncertain whether robots with different designs could lead to different results in the accuracy of pedicle screw placement. This study aimed to compare the pedicle screw inserting accuracies among the spinal surgeries assisted by various types of robot and estimate the rank probability of each robot-assisted operative technique involved.MethodsThe electronic literature database of PubMed, Web of Science, EMBASE, CNKI, WANFANG and the Cochrane Library was searched in November 2021. The primary outcome was the Gertzbein–Robbins classification of pedicle screws inserted with various operative techniques. After the data extraction and direct meta-analysis process, a network model was established in the Bayesian framework and further analyses were carried out.ResultsAmong all the 15 eligible RCTs, 4 types of robot device, namely Orthbot, Renaissance, SpineAssist and TiRobot, were included in this study. In the network meta-analysis, the Orthbot group (RR 0.27, 95% CI 0.13–0.58), the Renaissance group (RR 0.33, 95% CI 0.14–0.86), the SpineAssist group (RR 0.14, 95% CI 0.06–0.34) and the conventional surgery group (RR 0.21, 95% CI 0.13–0.31) were inferior to the TiRobot group in the proportion of grade A pedicle screws. Moreover, the results of rank probabilities revealed that in terms of accuracy, the highest-ranked robot was TiRobot, followed by Renaissance and Orthbot.ConclusionsIn general, current RCT evidence indicates that TiRobot has an advantage in the accuracy of the pedicle screw placement, while there is no significant difference among the Orthbot-assisted technique, the Renaissance-assisted technique, the conventional freehand technique, and the SpineAssist-assisted technique in accuracy.

Marker Screw Utilization for Minimally Invasive Transforaminal Lumbar Interbody Fusion (MS-MIS TLIF): Promises and Advantages.

Background and Objective: Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS-TLIF) has been investigated and shown excellent short- and long-term outcomes. In this paper, we describe a new MIS-TLIF technique and pedicle screw insertion using a marker screw as a guidance method. Moreover, we report perioperative, postoperative, and patient-related outcomes. In addition, this paper outlines major differences in radiation exposure, cost effectiveness and accuracy of Marker Screw Minimally Invasive Transforaminal Interbody Fusion (MS-MIS TLIF) compared to other techniques. We report our technique to share our knowledge and experience with the aim of achieving a better MIS-TLIF that would help both surgeons and patients. Materials and Methods: A prospective case series was conducted between October 2018 and February 2021. Patients undergoing MS-MIS TLIF with marker screws were consecutively included. The surgery did not exceed two levels. The patients' medical records were reviewed, and the included patients were asked to complete two outcome-questionnaires before surgery and at the six-month visit. The surgical technique is described in this paper. Results: A total of 37 patients were recruited. The mean age was 57.35 ± 12.8 years, and more than half of the patients were females. The most common indications for surgery were degenerative disc disease and spondylolisthesis, with the typical level at L4-5. The operative time was 3.02 ± 0.83 h, while the estimated blood loss was 127.7 ± 71.1 mL. The average time for ambulation and hospitalization was 1 ± 1.1 and 2.84 ± 1.4 days, respectively. The patients described significant improvement in both questionnaires. No screw-related complications or screw revisions were needed up to two years of follow-up. Conclusions: The use of marker screws for pedicle screw placement through a minimally invasive fashion is shown to be a promising technique that can overcome many drawbacks, including cost, operative time, and radiation exposure. Performing MS-MIS TLIF can achieve a 360- degree fusion compared to percutaneous MIS-TLIF.

Posterior Preventive Foraminotomy before Laminectomy Combined with Pedicle Screw Fixation May Decrease the Incidence of C5 Palsy in Complex Cervical Spine Surgery in Patients with Severe Myeloradiculopathy.

C5 palsy is a frequent sequela of cervical decompression surgeries for cervical myeloradiculopathy. Although many researchers have suggested various risk factors, such as cord shifting and the correction of lordotic angles, the tethering of the C5 root beneath the narrow foramen is an independent risk factor for C5 palsy. In this study, we tried to investigate different techniques for foramen decompression with posterior cervical fusion and assess the incidence of C5 palsy with each technique depending on the order of foraminal decompression. A combined 540° approach with LMS and uncovertebrectomy was used in group 1. Group 2 combined a 540° approach with pedicle screws and posterior foraminotomy, while posterior approach only with pedicle screws and foraminotomy was used in group 3. For groups 2 and 3, prophylactic posterior foraminotomy was performed before laminectomy. Motor manual testing to assess C5 palsy, the Neck Disability Index (NDI) and the Japanese Orthopedic Association (JOA) scores were determined before and after surgery. Simple radiographs, MRI and CT scans, were obtained to assess radiologic parameters preoperatively and postoperatively. A total of 362 patients were enrolled in this study: 208 in group 1, 72 in group 2, and 82 in group 3. The mean age was 63.2, 65.5, and 66.6 years in groups 1, 2, and 3, respectively. The median for fused levels was 4 for the three groups. There was no significant difference between groups regarding the number of fused levels. Weight, height, comorbidities, and diagnosis were not significantly different between groups. Preoperative JOA scores were similar between groups (p = 0.256), whereas the preoperative NDI score was significantly higher in group 3 than in group 2 (p = 0.040). Mean JOA score at 12-month follow-up was 15.5 ± 1.89, 16.1 ± 1.48, and 16.1 ± 1.48 for groups 1, 2, and 3, respectively; it was higher in group 3 compared with group 1 (p = 0.008) and in group 2 compared with group 1 (p = 0.024). NDI score at 12 months was 13, 12, and 13 in groups 1, 2, and 3, respectively; it was significantly better in group 3 than in group 1 (p = 0.040), but there were no other significant differences between groups. The incidence of C5 palsy was significantly lower in posterior foraminotomy groups with pedicle screws (groups 2 and 3) than in LMS with uncovertebrectomy (group 1) (p < 0.001). Thus, preventive expansive foraminotomy before decompressive laminectomy is able to significantly decrease the root tethering by stenotic lesion, and subsequently, decrease the incidence of C5 palsy associated with posterior only or combined posterior and anterior cervical fusion surgeries. Additionally, such expansive foraminotomy might be appropriate with pedicle screw insertion based on biomechanical considerations.

Morphometric Study of Sub Axial Cervical Spine Pedicles in Nepalese Population.

Mal-positioning of cervical screws risks neurovascular injury so, it is necessary to understand cervical pedicle morphology for pedicle screw fixation in the region. The risks of pedicle screw insertion in the cervical spine can be mitigated by a three-dimensional appreciation of pedicle anatomy. The study aims to determine the morphology of the sub axial cervical spine pedicles in Nepalese Population based on computerized tomography. A cross-sectional study using computerized tomography scans of the spine was made among the randomly selected 87 patients who had visited National Trauma center, Kathmandu, Nepal with vertebral fracture other than cervical vertebrae. Patient was examined as per Advanced Trauma Life support protocol and neurological assessment. Measurement was done from the third cervical vertebra down to the seventh cervical vertebra in computer with standard software in the department of radiology from where all the computerized tomography scan reporting are done. The mean pedicle length ranged from 4.41 mm at C3 to 4.96 mm at C7 where mean pedicle height ranged from 4.64 at C3 to 5.12 at C7. Pedicle length, pedicle height and pedicle width were observed to be statistically significant with gender. The pedicle axial length of C3 and C7 vertebra were found significant with gender. All parameters were found to be greater in male compared to female. The study revealed that pedicle length, pedicle height, pedicle width, pedicle axial length increased from third to seventh cervical however, transverse angulation increased up to fifth vertebra and decreased to seventh vertebra.

Stress Distribution of Different Pedicle Screw Insertion Techniques Following Single-Segment TLIF: A Finite Element Analysis Study.

At present, a variety of posterior lumbar internal fixation implantation methods have been developed, which makes it difficult for spine surgeons to choose. The stress distribution of the internal fixation system is one of the important indexes to evaluate these technologies. Common insertion technologies include Roy Camille, Magerl, Krag, AO, and Weinstein insertion techniques. This study aimed to compare the distribution of von Mises stresses in different screw fixation systems established by these insertion technologies. Here, the three-dimensional finite element (FE) method was selected to evaluate the postoperative stress distribution of internal fixation. Following different pedicle screw insertion techniques, five single-segment transforaminal lumbar interbody fusion (TLIF) models were established after modeling and validation of the L1-S1 vertebrae FE model. By analyzing the data, we found that stress concentration phenomenon was in all the models. Additionally, Roy-Camille, Krag, AO, and Weinstein insertion techniques led to the great stress on lumbar vertebra, intervertebral disc, and screw-rod fixation systems. Therefore, we hope that the results can provide ideas for clinical work and development of pedicle screws in the future. It is worth noting that flexion, unaffected side lateral bending, and affected side axial rotation should be limited for the patients with cages implanted. Overall, our method obtained the results that Magerl insertion technique was the relatively safe approach for pedicle screw implantation due to its relatively dispersive stress in TLIF models.

High Rate of Pulmonary Cement Embolism after Cement-Augmented Pedicle Screw Fixation: A 12-Year Single-Center Study.

The global trend toward increased life expectancy because of remarkable improvements in health care quality has drawn increased attention to osteoporotic fractures and degenerative spine diseases. Cement-augmented pedicle screw fixation has been established as the mainstay treatment for patients with poor bone quality. This study aimed to determine the number of patients with cement leakage and pulmonary cement embolism (PCE) as detected on thoracic computed tomography (CT), and to assess the potential risk factors for PCE. Patients undergoing cement-augmented pedicle screw placement in our institution between May 2008 and December 2020 were included. Data regarding baseline characteristics, complications, and cement leakage rates were collected. Indications for the performance of a postoperative thoracic CT due to the suspicion of PCE were intra- or postoperative complications, or postoperative oxygen supplementation. Moreover, PCE was accidently diagnosed because the thoracic CT was performed for medical reasons other than the suspicion of PCE (tumor staging, severe pneumonia, or exacerbated chronic pulmonary obstructive disease). A total of 104 patients with a mean age of 72.8 years (standard deviation of 6.7) were included. Of 802 screws, 573 were cement augmented. Of the 104 patients, 44 (42.3%) underwent thoracic CT scans to diagnose PCE; additionally, 67 (64.4%) demonstrated cement leakage, of whom 27 developed PCE and 4 were symptomatic. Cement-augmented thoracic screws were a risk factor for PCE (odds ratio: 1.5; 95% confidence interval: 1.2-2.1; p = 0.004). This study showed a high prevalence of cement leakage after cement-augmented pedicle screw insertion, with a relatively frequent incidence of PCE, as tracked by thoracic CT scans. Cement-augmented thoracic screw placement was a unique risk factor for PCE.

Pedicle morphometry analysis of main thoracic apex adolescent idiopathic scoliosis

IntroductionScrew insertion during scoliosis surgery uses free-hand pedicle screw insertion methods. However, there is a wide variation in pedicle shapes, sizes, and morphometry, especially in scoliosis patients. CT scan pedicle measurements in main thoracic Lenke type 1 adolescent idiopathic scoliosis can help visualize this diversity. This study aimed to highlight the features of pedicle morphometry on the concave and convex sides, including pedicle diameter (width in axial and height in the sagittal plane), the depth to the anterior cortex, and Watanabe Pedicle classification in patients with main thoracic apex adolescent idiopathic scoliosis.Materials and methodsThis study was a cross-sectional observational study of Adolescent Idiopathic Scoliosis (AIS) patients whose apex in the main thoracic patient underwent deformity correction procedures. We used a three-dimensional CT scan to evaluate pedicle morphometry on the apex vertebrae, three consecutive vertebrae above and below the apex.ResultsA total of 6 patients with apex main thoracic AIS with 84 pedicles consisting of 42 pedicles from each concave and convex curve were analyzed. All of the samples were female, with the mean age at the procedure being 21.2 ± 5.56. The mean cobb angle was 62° ± 23°, with the main apex between VT8-VT10. The size of the pedicle was bigger from upper to lower vertebrae. The mean pedicle depth, pedicle width, and pedicle height for the concave side were 36.06 ± 4.31 mm, 3.91 ± 0.66 mm, and 9.16 ± 1.52 mm, respectively. Meanwhile, the convex side is 37.52 ± 1.84 mm, 5.20 ± 0.55 mm, and 11.05 ± 0.70 mm, respectively. We found a significant difference between the concave and convex sides for the pedicle width and height. The concave and convex sides were mainly classified as type C (38%) and type A (50%) Watanabe pedicle.ConclusionPedicle width and pedicle height are significantly different between the concave and the convex side with convex side has better Watanabe pedicle classification. Pre-operative CT evaluation is essential for planning proper pedicle screw placement in AIS patients.

Morphometric Study and Anatomical Variation with its Incidence of Foramina Transversaria on the Lower Cervical Vertebrae

Anatomical variation of the foramina transversaria (FT) is associated with vertebral neurovascular symptoms and can cause complications after lower spine surgery, especially cervical pedicle screw (CPS) insertion. FT variation has been documented and classified in various populations, as this information can help increase cervical stability in subaxial vertebral surgery. Although the morphometry of the upper cervical spine in Thai populations has been reported, there have yet been no studies examining the features of FT. The FT of dried cervical spines (C3-C7; left and right side; n = 107, male = 53 and female = 54) were examined for morphological variation, and their anteroposterior (AP) and transverse (T) diameters were measured using a digital vernier caliper. Morphometric data and variations were compared by sex and lateral side. It was that the C3-C6 FT in both sexes were round, and the C7 FT was elliptical with an oblique right side. FT diameters did not differ significantly by sex except for the AP diameters of C6-C7 and for T diameters of C4 and C7. The left AP diameters of C3-C6 were significantly longer than the right, as were the T diameters of C4 and C7 FT. Additionally, T diameter was significantly longer than that of the AP, except that of the left C6 in male spines, which did not differ from the AP. Most FT examined were round. These findings should be considered in the provisional diagnosis of vertebral neurovascular symptoms caused by FT variation as well as that of neurovascular damage after cervical pedicle screw placement.

Accuracy of atlantoaxial screw placement using computed tomography-based navigation system-assisted surgery: The single-level vertebral registration

ObjectivePosterior screw fixation via a C1 lateral mass screw combined with a C2 pedicle screw is a well-known technique for atlantoaxial instability. However, screw malposition can occur because of the complex anatomical structure of this region. This study aimed to evaluate the accuracy and risk factors of cortical breach following the C1 lateral mass and/or C2 pedicle screw insertion using a preoperative computed tomography (CT)-based navigation system with a single-level vertebral registration method. MethodsThis retrospective cohort study included patients who had undergone a C1 lateral mass and/or a C2 pedicle screw placement using a preoperative CT-based navigation system from January 2013 to March 2020 from the university hospital. The extent of screw deviation was classified as: within the pedicle (grade 0), out of pedicle < 2 mm (grade I), from 2 to 4 mm (grade II), and > 4 mm (grade III). The risk of cortical breach was evaluated using multivariate analysis. ResultsSeventy-eight C1 lateral masses and 71 C2 pedicle screws were inserted into 42 patients. The accuracy of screw placement was as follows: 133 grade 0 (89.3 %), 14 grade I (9.4 %), and two grade II (1.3 %). No screws required repositioning, and no vertebral artery injury or neurological deficit was associated with this technique. Additionally, a diameter of < 5 mm was associated with the cortical breach in the multivariate analysis. ConclusionsC1 lateral mass and C2 pedicle screw placement could be safely and effectively performed by using a preoperative CT-based navigation system with a single-level registration technique. The risk factors for cortical breach are the C1 lateral mass and C2 pedicle diameters.

Low Radiation Protocol for Intraoperative Robotic C-Arm Can Enhance Adolescent Idiopathic Scoliosis Deformity Correction Accuracy and Safety.

Retrospective case-series study. To assess (1) low cone beam CT (CBCT) mediated intraoperative navigation to limit radiation exposure without compromising surgical accuracy, and (2) the potential of intraoperative C-arm CBCT navigation to augment pedicle screw (PS) placement accuracy in AIS surgery compared to pre-surgery CT-based planning. The first part involved a prospective phantom study, comparing radiation doses for conventional CT, and standard (6sDCT) and a low dose (5sDCT) Artis Zeego®-imaging. Next, 5sDCT- and 6sDCT-navigation were compared on PS accuracy and radiation exposure during AIS correction. The final part compared surgical AIS deformity correction through intraoperative 5sDCT navigation to a matched cohort treated using conventional pre-surgery CT-scans for navigation. Outcome parameters included operation time, skin dose (SD), dose area product (DAP), intraoperative blood loss, postoperative complications, and PS deviation rates. The phantom study demonstrated a reduction in radiation for the 5sDCT protocol. Moreover, 5sDCT-imaged patients (n = 15) showed a significantly lower SD (-27.41%) and DAP (-30.92%), without compromising PS accuracy compared with 6sDCT-settings (n = 15). Finally, AIS correction through intraoperative CBCT C-arm navigation (n = 27) significantly reduced screw deviation rates (6.83% versus 10.75%, P = .016) without increasing operation times, compared with conventional CT (n = 37). Intraoperative navigation using a CBCT C-arm system improved the accuracy of PS insertion and reduced surgery time. Moreover, it reduced radiation exposure compared with conventional CT, which was further curtailed by adapting the low-dose 5sDCT protocol. In short, our study highlights the benefits of intraoperative CBCT navigation for PS placement in AIS surgery.

A technical note of an alternative way for lumbar pedicle screw insertion

Posterior stabilization using pedicle screw is a basic procedure in lumbar spine surgery. The success of this procedure requires learning curve, experience as well as knowledge on anatomical landmarks. Breach into vital structures of or around the spine due to mistakes in screw insertion may result in detrimental results. This technical note proposes a technique to insert lumbar pedicle screws in a relatively easier manner and more consistent for each lumbar vertebral level.

A Dual-Screw Technique for Vertebral Compression Fractures via Robotic Navigation in the Osteopenic Lumbar Spine: An In-Vitro Biomechanical Analysis.

Biomechanical cadaveric study. Multi-rod constructs maximize posterior fixation, but most use a single pedicle screw (PS) anchor point to support multiple rods. Robotic navigation allows for insertion of PS and cortical screw (CS) within the same pedicle, providing 4 points of bony fixation per vertebra. Recent studies demonstrated radiographic feasibility for dual-screw constructs for posterior lumbar spinal fixation; however, biomechanical characterization of this technique is lacking. Fourteen cadaveric lumbar specimens (L1-L5) were divided into 2 groups (n = 7): PS, and PS + CS. VCF was simulated at L3. Bilateral posterior screws were placed from L2-L4. Load control (±7.5Nm) testing performed in flexion-extension (FE), lateral bending (LB), axial rotation (AR) to measure ROM of: (1) intact; (2) 2-rod construct; (3) 4-rod construct. Static compression testing of 4-rod construct performed at 5mm/min to measure failure load, axial stiffness. Four-rod construct was more rigid than 2-rod in FE (P < .001), LB (P < .001), AR (P < .001). Screw technique had no significant effect on FE (P = .516), LB (P = .477), or AR (P = .452). PS + CS 4-rod construct was significantly more stable than PS group (P = .032). Stiffness of PS + CS group (445.8 ± 79.3N/mm) was significantly greater (P = .019) than PS (317.8 ± 79.8N/mm). Similarly, failure load of PS + CS group (1824.9 ± 352.2N) was significantly greater (P = .001) than PS (913.4 ± 309.8N). Dual-screw, 4-rod construct may be more stable than traditional rod-to-rod connectors, especially in axial rotation. Axial stiffness and ultimate strength of 4-rod, dual-screw construct were significantly greater than rod-to-rod. In this study, 4-rod construct was found to have potential biomechanical benefits of increased strength, stiffness, stability.

Tap or not to tap before pedicle screw insertion - Perioperative analysis

Tap or not to tap before pedicle screw insertion - Perioperative analysis

Spinal robotics in cervical spine surgery: a systematic review with key concepts and technical considerations.

Spinal robotics for thoracolumbar procedures, predominantly employed for the insertion of pedicle screws, is currently an emerging topic in the literature. The use of robotics in instrumentation of the cervical spine has not been broadly explored. In this review, the authors aimed to coherently synthesize the existing literature of intraoperative robotic use in the cervical spine and explore considerations for future directions and developments in cervical spinal robotics. A literature search in the Web of Science, Scopus, and PubMed databases was performed for the purpose of retrieving all articles reporting on cervical spine surgery with the use of robotics. For the purposes of this study, randomized controlled trials, nonrandomized controlled trials, retrospective case series, and individual case reports were included. The Newcastle-Ottawa Scale was utilized to assess risk of bias of the studies included in the review. To present and synthesize results, data were extracted from the included articles and analyzed using the PyMARE library for effect-size meta-analysis. On careful review, 6 articles published between 2016 and 2022 met the inclusion/exclusion criteria, including 1 randomized controlled trial, 1 nonrandomized controlled trial, 2 case series, and 2 case reports. These studies featured a total of 110 patients meeting the inclusion criteria (mean age 53.9 years, range 29-77 years; 64.5% males). A total of 482 cervical screws were placed with the use of a surgical robot, which yielded an average screw deviation of 0.95 mm. Cervical pedicle screws were the primary screw type used, at a rate of 78.6%. According to the Gertzbein-Robbins classification, 97.7% of screws in this review achieved a clinically acceptable grade. The average duration of surgery, blood loss, and postoperative length of stay were all decreased in minimally invasive robotic surgery relative to open procedures. Only 1 (0.9%) postoperative complication was reported, which was a surgical site infection, and the mean length of follow-up was 2.7 months. No mortality was reported. Robot-assisted cervical screw placement is associated with acceptable rates of clinical grading, operative time, blood loss, and postoperative complications-all of which are equal to or improved relative to the metrics seen in the conventional use of fluoroscopy or computer-assisted navigation for cervical screw placement.