Accuracy and risk factors of Magerl screw placement in robot-assisted atlantoaxial surgery: A case series study.

BACKGROUND: To assess the accuracy of robot-assisted Magerl screw placement and explore the factors affecting the accuracy. METHODS: A retrospective analysis of patients who underwent robot-assisted Magerl screw placement was performed. The accuracy of Magerl screw placement was evaluated according to the Gertzbein and Robbins scale. RESULTS: 47 Magerl screws were placed in 24 consecutive patients. 32 Magerl screws were narrower than the C2 isthmus height and 26 of them were grade A. 15 Magerl screws were wider than the C2 isthmus height and all of them were grade B. Temporary fixation after decompression and a smaller difference between the C2 isthmus height and screw diameter were associated with a higher probability of cortical breach. CONCLUSION: The accuracy of robot-assisted Magerl screw placement was excellent. Temporary fixation after decompression and a smaller difference between the C2 isthmus height and screw diameter increased the risk of cortical breach.

Comparative efficacy of robotic-assisted and freehand techniques for pedicle screw placement in spinal disorders: a meta-analysis and systematic review.

The efficacy and safety of robotic-assisted pedicle screw placement compared to traditional fluoroscopy-guided techniques are of great interest in the field of spinal surgery. This systematic review and meta-analysis aimed to compare the outcomes of these two methods in patients with spinal diseases. Following the PRISMA guidelines, we conducted a systematic search across PubMed, Embase, Web of Science, and Cochrane Library. We included randomized controlled trials comparing robotic-assisted and fluoroscopy-guided pedicle screw placement in patients with spinal diseases. Outcome measures included the accuracy of pedicle screw placement, postoperative complication rates, intraoperative radiation exposure time, and duration of surgery. Data were analyzed using Stata software. Our analysis included 12 studies. It revealed significantly higher accuracy in pedicle screw placement with robotic assistance (odds ratio [OR] = 2.83, 95% confidence interval [CI] = 2.20-3.64, P < 0.01). Postoperative complication rates, intraoperative radiation exposure time, and duration of surgery were similar between the two techniques (OR = 0.72, 95% CI = 0.31 to 1.68, P = 0.56 for complication rates; weighted mean difference [WMD] = - 0.13, 95% CI = - 0.93 to 0.68, P = 0.86 for radiation exposure time; WMD = 0.30, 95% CI = - 0.06 to 0.66, P = 0.06 for duration of surgery). Robotic-assisted pedicle screw placement offers superior placement accuracy compared to fluoroscopy-guided techniques. Postoperative complication rates, intraoperative radiation exposure time, and duration of surgery were comparable for both methods. Future studies should explore the potential for fewer complications with the robotic-assisted approach as suggested by the lower point estimate.

Hybrid kyphoplasty with short-versus intermediate- and long-segment pedicle screw fixations for the management of thoracolumbar burst fractures.

BACKGROUND: This study aimed to determine if the hybrid short-segment (HSS) technique is a good alternative to the intermediate-segment (IS) and long-segment (LS) techniques in pedicle screw fixations for acute thoracolumbar burst fractures (TLBFs). METHODS: In this retrospective evaluation, we examined 43 patients who underwent surgical treatments, including one- or two-level suprajacent (U) and infrajacent (L) pedicle screw fixations, for acute single-level TLBFs with neurological deficits between the T11 and L2 levels from July 2013 to December 2019. Among these patients, 15 individuals underwent HSS (U1L1), 12 received IS (U2L1), and 16 underwent LS (U2L2) fixations. Supplemental kyphoplasty of the fractured vertebral bodies was performed exclusively in the HSS group. Our analysis focused on assessing blood loss and surgical duration. Additionally, we compared postoperative thoracolumbar kyphotic degeneration using the data on Cobb angles on lateral radiographic images acquired at three time points (preoperatively, postoperative day 1, and follow-up). The end of follow-up was defined as the most recent postoperative radiographic image or implant complication occurrence. RESULTS: Blood loss and surgical duration were significantly lower in the HSS group than in the IS and LS groups. Additionally, the HSS group exhibited the lowest implant complication rate (2/15, 13.33%), followed by the LS (6/16, 37.5%) and IS (8/12, 66.7%) group. Implant complications occurred at a mean follow-up of 7.5 (range: 6-9), 9 (range: 5-23), and 7 (range: 1-21) months in the HSS, IS, and LS groups. Among these implant complications, revision surgeries were performed in two patients in the HSS group, two in the IS group, and one in the LS group. One patient treated by HSS with balloon kyphoplasty underwent reoperation because of symptomatic cement leakage. CONCLUSIONS: The HSS technique reduced intraoperative blood loss, surgical duration, and postoperative implant complications, indicating it is a good alternative to the IS and LS techniques for treating acute single-level TLBFs. This technique facilitates immediate kyphosis correction and successful maintenance of the corrected alignment within 1 year. Supplemental kyphoplasty with SpineJack® devices and high-viscosity bone cements for anterior reconstruction can potentially decrease the risk of cement leakage and related issues.

Risk Factors for Medial Breach During Robotic-Assisted Cortical Bone Trajectory Screw Insertion.

OBJECTIVE: We describe the incidence of, and identify the risk factors for, a medial breach of the pedicle wall during robotic-assisted cortical bone trajectory (RA-CBT) screw insertion. METHODS: We analyzed a consecutive series of adult patients who underwent RA-CBT screw placement from January 2019 to July 2022. To assess the pedicle wall medial breach, postoperative computed tomography (CT) images were analyzed. Patient demographic data and screw data were compared between patients with and without a medial breach. The Hounsfield units (HUs) on the L1 midvertebral axial CT scan was used to evaluate bone quality. RESULTS: Of 784 CBT screws in 145 patients, 30 (3.8%) had a medial breach in 23 patients (15.9%). One screw was grade 2, and the others were grade 1. Patients with a medial breach had a lower HU value compared with the patients without a medial breach (123.3 vs. 150.5; P = 0.027). A medial breach was more common in the right than left side (5.5% vs. 2.0%; P = 0.014). More than one half of the screws with a medial breach were found in the upper instrumented vertebra (UIV) compared with the middle construct or lowest instrumented vertebra (6.7% vs. 1.3% vs. 2.7%; P = 0.003). Binary logistic regression showed that low HU values, right-sided screw placement, and UIV were associated with a medial breach. No patients returned to the operating room for screw malposition. No differences were found in the clinical outcomes between patients with and without a medial breach. CONCLUSIONS: The incidence of pedicle wall medial breach was 3.8% of RA-CBT screws in the postoperative CT images. A low HU value measured in the L1 axial image, right-sided screw placement, and UIV were associated with an increased risk of medial breach for RA-CBT screw placement.

Navigation-Assisted One-Staged Posterior Spinal Fusion Using Pedicle Screw Instrumentation in Adolescent Idiopathic Scoliosis-A Case Series.

Background and Objectives: Adolescent idiopathic scoliosis (AIS) is a prevalent three-dimensional spinal disorder, with a multifactorial pathogenesis, including genetics and environmental aspects. Treatment options include non-surgical and surgical treatment. Surgical interventions demonstrate positive outcomes in terms of deformity correction, pain relief, and improvements of the cardiac and pulmonary function. Surgical complications, including excessive blood loss and neurologic deficits, are reported in 2.27-12% of cases. Navigation-assisted techniques, such as the O-arm system, have been a recent focus with enhanced precision. This study aims to evaluate the results and complications of one-stage posterior instrumentation fusion in AIS patients assisted by O-arm navigation. Materials and Methods: This retrospective study assesses 55 patients with AIS (12-28 years) who underwent one-stage posterior instrumentation correction supported by O-arm navigation from June 2016 to August 2023. We examined radiological surgical outcomes (initial correction rate, loss of correction rate, last follow-up correction rate) and complications as major outcomes. The characteristics of the patients, intraoperative blood loss, operation time, number of fusion levels, and screw density were documented. Results: Of 73 patients, 55 met the inclusion criteria. The average age was 16.67 years, with a predominance of females (78.2%). The surgical outcomes demonstrated substantial initial correction (58.88%) and sustained positive radiological impact at the last follow-up (56.56%). Perioperative complications, including major and minor, occurred in 18.18% of the cases. Two patients experienced a major complication. Blood loss (509.46 mL) and operation time (402.13 min) were comparable to the literature ranges. Trend analysis indicated improvements in operation time and blood loss over the study period. Conclusions: O-arm navigation-assisted one-stage posterior instrumentation proves reliable for AIS corrective surgery, achieving significant and sustained positive radiological outcomes, lower correction loss, reduced intraoperative blood loss, and absence of implant-related complications. Despite the challenges, our study demonstrates the efficacy and maturation of this surgical approach.

T1 Pedicle Subtraction Osteotomy With Subaxial Cervical Pedicle Screw Fixation.

Patients suffering from ankylosing spondylitis are not only predisposed to the development of rigid cervicothoracic deformities but are also at an increased risk of cervical fractures. Deformity correction and stabilization are particularly challenging in this patient population due to the brittle bone quality and low bone mineral density. Thoracic pedicle subtraction osteotomy is a workhorse approach for the correction of focal severe kyphotic deformity with lower complication rates than 3-column osteotomy. Successful execution of an upper thoracic PSO requires careful presurgical planning as well as anticipation of the patient's postoperative needs. Here, we describe the use of a T1 PSO in the correction of a rigid cervicothoracic chin-on-chest deformity in a patient with AS. The risk of implant failure was reduced by the use of a multi-rod construct, navigated cervical pedicle screws, and dual-pitched thoracic pedicle screws.

Pedicle screw placement accuracy in robot-assisted versus image-guided freehand surgery of thoraco-lumbar spine (ROBARTHRODESE): study protocol for a single-centre randomized controlled trial.

BACKGROUND: Robotic spinal surgery may result in better pedicle screw placement accuracy, and reduction in radiation exposure and length of stay, compared to freehand surgery. The purpose of this randomized controlled trial (RCT) is to compare screw placement accuracy of robot-assisted surgery with integrated 3D computer-assisted navigation versus freehand surgery with 2D fluoroscopy for arthrodesis of the thoraco-lumbar spine. METHODS: This is a single-centre evaluator-blinded RCT with a 1:1 allocation ratio. Participants (n = 300) will be randomized into two groups, robot-assisted (Mazor X Stealth Edition) versus freehand, after stratification based on the planned number of pedicle screws needed for surgery. The primary outcome is the proportion of pedicle screws placed with grade A accuracy (Gertzbein-Robbins classification) on postoperative computed tomography images. The secondary outcomes are intervention time, operation room occupancy time, length of stay, estimated blood loss, surgeon's radiation exposure, screw fracture/loosening, superior-level facet joint violation, complication rate, reoperation rate on the same level or one level above, functional and clinical outcomes (Oswestry Disability Index, pain, Hospital Anxiety and Depression Scale, sensory and motor status) and cost-utility analysis. DISCUSSION: This RCT will provide insight into whether robot-assisted surgery with the newest generation spinal robot yields better pedicle screw placement accuracy than freehand surgery. Potential benefits of robot-assisted surgery include lower complication and revision rates, shorter length of stay, lower radiation exposure and reduction of economic cost of the overall care. TRIAL REGISTRATION: ClinicalTrials.gov NCT05553028. Registered on September 23, 2022.

Establishment and Validation of Nomograms and Web Calculators for Different Cement Leakage Risk Types in Pedicle Screw Augmentation for Degenerative Lumbar Stenosis in Osteoporotic Vertebrae.

BACKGROUND: The use of cement in pedicle screw augmentation (PSA) enhances the pullout force of pedicle screws in vertebrae affected by osteoporosis. Risks involved in the use of cement for PSA include nerve injury and vascular damage caused by cement leakage. METHODS: This study included all patients who received PSA for degenerative lumbar stenosis in osteoporotic vertebrae from January 2014 to May 2022. Postoperative computed tomography was used to assess cement leakage. Correlation analysis and logistic regression analyses were used to establish the associated clinical or radiological factors, which were then used to construct nomograms and web calculators. RESULTS: The study comprised 181 patients including 886 screws inserted into 443 vertebrae. Perivertebral cement leakage was significantly associated with female sex, decreased bone mineral density, solid screws, and scattered cement distribution. Cement leakage through segmental veins (type S, 72.1%), leakage through basivertebral veins (type B, 23.9%), and instrument-related leakage (type I, 13.9%) accounted for most cement leakage. Patients with lower bone mineral density and scattered cement distribution were more likely to experience type S or type B leakage. Our analysis data showed that cement augmentation with cannulated and fenestrated screws tended toward concentrated cement distribution. Creation and verification of each nomogram additionally showcased the prognostic capability and medical significance of the corresponding model. CONCLUSIONS: Nomograms and web-based calculators can accurately forecast the probability of cement leakage. PSA should be routinely performed using cannulated and fenestrated screws, along with a moderate amount of high-viscosity cement, with continuous monitoring using fluoroscopy.

Comparison of the clinical and radiographic outcomes of cortical bone trajectory and traditional trajectory pedicle screw fixation in transforaminal lumbar interbody fusion: a randomized controlled trial.

PURPOSE: To compare the clinical outcomes and radiographic outcomes of cortical bone trajectory (CBT) and traditional trajectory (TT) pedicle screw fixation in patients treated with single-level transforaminal lumbar interbody fusion (TLIF). METHODS: This trial included a total of 224 patients with lumbar spine disease who required single-level TLIF surgery. Patients were randomly assigned to the CBT and TT groups at a 1:1 ratio. Demographics and clinical and radiographic data were collected to evaluate the efficacy and safety of CBT and TT screw fixation in TLIF. RESULTS: The baseline characteristic data were similar between the CBT and TT groups. Back and leg pain for both the CBT and TT groups improved significantly from baseline to 24 months postoperatively. The CBT group experienced less pain than the TT group at one week postoperatively. The postoperative radiographic results showed that the accuracy of screw placement was significantly increased in the CBT group compared with the TT group (P < 0.05). The CBT group had a significantly lower rate of FJV than the TT group (P < 0.05). In addition, the rate of fusion and the rate of screw loosening were similar between the CBT and TT groups according to screw loosening criteria. CONCLUSION: This prospective, randomized controlled analysis suggests that clinical outcomes and radiographic characteristics, including fusion rates and caudal screw loosening rates, were comparable between CBT and TT screw fixation. Compared with the TT group, the CBT group showed advantages in the accuracy of screw placement and the FJV rate. CLINICAL TRIALS REGISTRATION: This trial has been registered at the US National Institutes of Health Clinical Trials Registry: NCT03105167.

Analysis of factors influencing the intravertebral shell phenomenon after posterior reduction internal fixation of thoracolumbar fracture: a retrospective study.

STUDY DESIGN: A retrospective study. PURPOSE: The study objectives were as follows: 1) to analyze the factors influencing the occurrence of the intravertebral shell phenomenon (ISP) after thoracolumbar spinal fracture surgery and the evolutionary outcome of this phenomenon; and 2) to make recommendations for the clinical prevention and treatment of ISP. METHODS: We retrospectively analyzed 331 patients with single-segment fractures of the thoracolumbar spine treated with internal fixation via a pedicle screw-rod system. Univariate and multivariate logistic regression were used to analyze factors influencing ISP. RESULTS: A total of 260 patients (78.5%) developed ISP after surgery. Reduced bone mineral density, screw insertion depth, degree of vertebral body injury, and excessive vertebral body spreading were significantly associated with the occurrence of ISP (P < 0.05). A total of 166 of the 260 patients were reviewed via CT at 1 year postoperatively. Among them, 104 patients (62.6%) showed shrinkage or healed vertebral cavities, and 62 patients (37.4%) showed enlarged vertebral cavities or collapsed endplates. CONCLUSION: In clinical management, surgeons need to focus on risk factors for ISP, which include decreased bone density, preoperative vertebral overcompression, intraoperative vertebral overextension, screw insertion depth, and the degree of vertebral repositioning. At the 1-year postoperative follow-up, some of the vertebrae with ISP failed to heal or even showed vertebral cleft enlargement, which would affect the stability of the internal fracture fixation device and the quality of the patient's daily life.

Risk factors of instrumentation failure after laminectomy and posterior cervical fusions (PCF).

BACKGROUND: For patients with multilevel degenerative cervical myelopathy, laminectomy and posterior cervical fusions (PCF) with instrumentation are widely accepted techniques for symptom relief. However, hardware failure is not rare and results in neck pain or even permanent neurological lesions. There are no in-depth studies of hardware-related complications following laminectomy and PCF with instrumentation. METHODS: The present study was a retrospective, single centre, observational study. Patients who underwent laminectomy and PCF with instrumentation in a single institution between January 2019 and January 2021 were included. Patients were divided into hardware failure and no hardware failure group according to whether there was a hardware failure. Data, including sex, age, screw density, end vertebra (C7 or T1), cervical sagittal alignment parameters (C2-C7 cervical lordosis, C2-C7 sagittal vertical axis, T1 slope, Cervical lordosis correction), regional Hounsfield units (HU) of the screw trajectory and osteoporosis status, were collected and compared between the two groups. RESULTS: We analysed the clinical data of 56 patients in total. The mean overall follow-up duration was 20.6 months (range, 12-30 months). Patients were divided into the hardware failure group (n = 14) and no hardware failure group (n = 42). There were no significant differences in the general information (age, sex, follow-up period) of patients between the two groups. The differences in fusion rate, fixation levels, and screw density between the two groups were not statistically significant (p > 0.05). The failure rate of fixation ending at T1 was lower than that at C7 (9% vs. 36.3%) (p = 0.019). The regional HU values of the pedicle screw (PS) and lateral mass screw (LMS) in the failure group were lower than those in the no failure group (PS: 267 ± 45 vs. 368 ± 43, p = 0.001; LMS: 308 ± 53 vs. 412 ± 41, p = 0.001). The sagittal alignment parameters did not show significant differences between the two groups before surgery or at the final follow-up (p > 0.05). The hardware failure rate in patients without osteoporosis was lower than that in patients with osteoporosis (14.3% vs. 57.1%) (p = 0.001). CONCLUSIONS: Osteoporosis, fixation ending at C7, and low regional HU value of the screw trajectory were the independent risk factors of hardware failure after laminectomy and PCF. Future studies should illuminate if preventive measures targeting these factors can help reduce hardware failure and identified more risk factors, and perform long-term follow-up.

Anatomic distribution of basivertebral foramen with a magistral form in vertebral bodies of T10~L5 and its clinical significance for extensive epidural cement leakage in cement-augmented pedicle screw fixation: a multicenter case-control study.

BACKGROUND: There are no reports discussing anatomic distribution of basivertebral foramen (BVF) in the osteoporotic vertebral body, which is critical in the analysis of the risk of epidural cement leakage (ECL) after cement-augmented pedicle screw fixation (CAPSF). METHODS: 371 osteoporotic patients using 1898 cement-augmented screws were included. Preoperative computed tomography (CT) was used to determine the frequency, width, height, and depth of magistral BVF in T10~L5. Additionally, we measured the distance between BVF and the left/right borders of vertebral body as well as the distance between BVF and upper/lower endplates. Following CAPSF, the severity of ECL and the position of pedicle screws were determined by postoperative CT. Finally, significant risk factors for extensive ECL were identified through binary logistic regression analysis. RESULTS: Of 2968 vertebral bodies ranging from T10 to L5, 801 (42.2%) had a magistral BVF. From T10 to L5, the frequency of magistral BVF appeared to gradually increase. The magistral BVF was much closer to the upper endplate and the depth accounted for about a quarter of anteroposterior diameter of vertebral body. Overall, there were 19 patients (5.1%) and 32 screws (1.7%) with extensive ECL, nine of whom had neurological symptoms. The independent risk factors for extensive ECL were the magistral BVF (OR = 8.62, P < 0.001), more volume of cement injected (OR = 1.57, P = 0.031), reduced distance from screw tip to vertebral midline (OR = 0.76, P = 0.003) and vertebral posterior wall (OR = 0.77, P < 0.001) respectively. CONCLUSION: When planning a CAPSF procedure, it is important to consider anatomical distribution of BVF and improve screw implantation methods.

Spinal Epidural Tuberculoma with Adjacent Vertebral Fracture: A Case Report.

CASE: An 85-year-old woman was transported to our institution due to difficulty in walking. Preoperative imaging showed spinal cord lesions indicative of spinal cord tumor at the T7-8 level, accompanied by T8 vertebral fracture. Intraoperatively, the spinal lesion was suspected to be an epidural abscess; therefore, the capsule was resected, and the abscess was drained. We added pedicle screw fixation at the T6-10 level. Postoperatively, the spinal cord lesion was definitively diagnosed as spinal epidural tuberculoma. CONCLUSION: Spinal epidural tuberculomas should be considered in the treatment of spinal cord lesions causing paralysis attributed to spinal cord compression.

Do Pedicle Screws That Terminate in the Costovertebral Joint Compromise Proximal Anchor Fixation in a Dual Growing Rod Construct?

INTRODUCTION: Growing rods (GRs) are used to treat early-onset scoliosis (EOS) recalcitrant to bracing and casting. Proximal anchor pullout, a known complication of GR constructs, can result in spinal cord injury if pedicle screw anchors are placed with a lateral-to-medial trajectory. To mitigate this risk, a more straightforward and potentially safer trajectory may result in screws that terminate within the costovertebral joint (CVJ). We asked, how often does CVJ placement occur and does this technique increase the rate of failure in GR constructs? METHODS: We retrospectively reviewed 35 patients with EOS treated with dual GR with >2-year follow-up excluding patients with skeletal dysplasia or history of previous posterior instrumentation. Patient demographics, radiographic parameters, and implant constructs were assessed. RESULTS: Of patients meeting the inclusion criteria, 18/35 (51%) were females with an average age of 7.96 (range: 4.0 to 15.2) years at surgery with a follow-up of 3.7 (range: 2.0 to 7.7) years. Five (14%) patients had idiopathic EOS, 5 (14%) had congenital EOS, 12 (34%) had neuromuscular EOS, 10 (29%) had syndromic scoliosis, and 3 (9%) had another etiology for EOS. Among 195 proximal pedicle screws placed, 19 (10%) terminated within the CVJ, and 13 patients (37%) had at least 1 CVJ screw. Two patients (6%) experienced unilateral proximal pullout. In both patients, the anchors on the affected side included 1 of 2 screws within the CVJ. Both patients had constructs that included 2 screws on the side that pulled out and 3 screws on the side that did not. None of the remaining 17 CVJ screws led to implant failure. CONCLUSION: Pedicle screw placement within the CVJ is common and does not appear to significantly contribute to proximal screw pullout; however, it may contribute to unilateral implant failure in constructs employing only 2 proximal screws, where 1 of those 2 screws terminates within the CVJ. Construct modifications should be considered in this scenario. LEVEL OF EVIDENCE: Level III.

Clinical outcomes of short rod technique in posterior lumbar interbody fusion surgery: a minimum of 2-year follow-up.

PURPOSE: We present for the first time a novel entry point of pedicle screws (Short Rod Technique, SRT), which can avoid superior facet violation and has been verified as a safe screw placement method. The purpose of this study is to determine the clinical outcomes of SRT in posterior lumbar interbody fusion (PLIF) surgery. METHODS: We retrospectively analyzed the clinical outcomes of 89 patients who received SRT and 109 patients who received PLIF surgery with regular entry points of pedicle screws with a minimum of 2 years of follow-ups. Patients were divided into three groups according to the number of fusion segments, and the clinical outcomes of the three groups were compared. RESULTS: The length of the wound and the length of rods were significantly shorter in the each SRT group. Less intraoperative blood loss was observed in the SRT group in patients with a single segment and two segments fusions, but not in three segments fusions. Fewer degenerations of the upper adjacent segment were observed in the SRT group in patients with a single segment and three segments fusions. In addition, less postoperative wound pain related to PLIF surgery was observed in the SRT group in patients with two and three segments fusions. CONCLUSION: SRT has been validated as an effective technique with good clinical outcomes, especially for reducing the occurrence of upper ASD in PLIF surgery with a single segment and three segments. The present study provides spinal surgeons with a novel method for performing PLIF surgery.

Robot-navigated pedicle screw insertion can reduce intraoperative blood loss and length of hospital stay: analysis of 1,633 patients utilizing propensity score matching.

BACKGROUND CONTEXT: Navigation and robotic technologies have emerged as an alternative option to conventional freehand techniques for pedicle screw insertion. However, the effectiveness of these technologies in reducing the perioperative complications of spinal fusion surgery remains limited due to the small cohort size in the existing literature. PURPOSE: To investigate whether utilization of robotically navigated pedicle screw insertion can reduce the perioperative complications of spinal fusion surgery-including reoperations-with a sizeable cohort. STUDY DESIGN: Retrospective study. PATIENT SAMPLE: Patients who underwent primary lumbar fusion surgery between 2019 and 2022. OUTCOME MEASURES: Perioperative complications including readmission, reoperation, its reasons, estimated blood loss, operative time, and length of hospital stay. METHODS: Patients' data were collected including age, sex, race, body mass index, upper-instrumented vertebra, lower-instrumented vertebra, number of screws inserted, and primary procedure name. Patients were classified into the following two groups: freehand group and robot group. The variable-ratio greedy matching was utilized to create the matched cohorts by propensity score and compared the outcomes between the two group. RESULTS: A total of 1,633 patients who underwent primary instrumented spinal lumbar fusion surgery were initially identified (freehand 1,286; robot 347). After variable ratio matching was performed with age, sex, body mass index, fused levels, and upper instrumented vertebrae level, 694 patients in the freehand group and 347 patients in robot groups were selected. The robot group showed less estimated blood loss (418.9±398.9 vs 199.2±239.6 ml; p<.001), shorter LOS (4.1±3.1 vs 3.2±3.0 days; p<.001) and similar operative time (212.5 vs 222.0 minutes; p=.151). Otherwise, there was no significant difference in readmission rate (3.6% vs 2.6%; p=.498), reoperation rate (3.2% vs 2.6%; p=.498), and screw malposition requiring reoperation (five cases, 0.7% vs one case, 0.3%; p=1.000). CONCLUSIONS: Perioperative complications requiring readmission and reoperation were similar between fluoroscopy guided freehand and robotic surgery. Robot-guided pedicle screw insertion can enhance surgical efficiency by reducing intraoperative blood loss and length of hospital stay without extending operative time.

Assessing the utility of MRI-based vertebral bone quality (VBQ) for predicting lumbar pedicle screw loosening.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: The purpose of this study is to assess the potential of utilizing the MRI-based vertebral bone quality (VBQ) score as a predictive tool for pedicle screw loosening (PSL) in patients who have undergone pedicle screw fixation and to identify risk factors associated with VBQ scores. METHODS: One hundred and sixteen patients who had undergone pedicle screw fixation between December 2019 and January 2021 and had more than a year of follow-up were divided into two groups of PSL and non-PSL. The radiological and clinical parameters investigated were age, gender, body mass index, the VBQ score, length of fusion and the DXA T-score. RESULTS: Of the 116 patients included in the study, 22 patients developed pedicle screw loosening after surgery (18.97%). VBQ score of PSL group was higher than the non-PSL group (3.61 ± 0.63 vs. 2. 86 ± 0.43, p < 0.001). According to logistic regression, PSL was independently linked with a higher VBQ score (OR = 3.555, 95% confidence interval [1.620-7.802], p < 0.005). The AUC of predicting screw loosening was 0.774 (p < 0.001) for VBQ score, and the best threshold was 3.055 (sensitivity, 81.8%; specificity, 71.3%). High VBQ score was associated with age (r (114) = 0.29, p = 0.002), while it was not negatively correlated with T-scores of each part. CONCLUSION: VBQ score is an independent predictor of pedicle screw loosening, with higher scores indicating a greater risk. Our results showed that older patients and women had higher VBQ scores.

Minimally Invasive Techniques in the Surgical Management of Traumatic Pediatric Thoracolumbar Fractures.

BACKGROUND: Thoracolumbar (TL) fractures are uncommon in children. While surgical treatment is recommended for unstable TL fractures, there is no consensus on appropriate surgical treatment. We present a case series of pediatric patients with traumatic TL fractures treated with minimally invasive techniques. We discuss our early experience and technical challenges with navigation and robotic-assisted fixation. METHODS: A retrospective review of a prospectively maintained trauma database from February 2018 to February 2023 of all pediatric patients (<18 years old) undergoing percutaneous fixation for unstable TL fractures was performed. Minimally invasive techniques included fluoroscopy and/or navigation-guided or robotic-assisted surgery. Clinical course, radiographic findings, and technical challenges were reviewed. RESULTS: A cohort of 12 patients (age range, 4-17 years) with 6 (50%) Chance fractures, 2 (16%) pars fractures, 2 (16%) pedicle fracture, 1 (8%) burst fracture, and 1 (8%) other fracture were identified. Nine patients had fractures involving the lumbar spine, and the remaining 3 had thoracic fractures. In all cases, percutaneous pedicle screws were placed above and below the fracture with the use of neuronavigation or robotic-assisted navigation (n = 2). Blood loss was <30 mL for single-level fractures and instrumented fusion. Two patients had hardware-related complications. At follow-up (mean 9.67 months after surgery), patients were doing well clinically, and most imaging showed stable alignment. CONCLUSIONS: Our early experience shows that short segment instrumentation through a minimally invasive approach is a safe and effective surgical option for young pediatric patients with good clinical outcomes and favorable radiographic postoperative finding.

Forearm bone mineral density predicts screw loosening after lumbar fusion similar to lumbar Hounsfield unit value in patients with lumbar spondylolisthesis.

Preoperative bone density assessment is necessary to predict screw loosening. The forearm BMD is a useful predictor of BMD-related complications after lumbar operation. Our results show that the forearm BMD is as effective a predictor of screw loosening as the lumbar average HU value. Measurement of the forearm BMD may be a useful adjunct in predicting screw loosening following lumbar fusion. PURPOSE: To determine the relationship between forearm bone mineral density (BMD) and the risk of pedicle screw loosening in patients with lumbar spondylolisthesis. METHODS: We retrospectively evaluated 270 patients who underwent posterior lumbar interbody fusion for lumbar spondylolisthesis. The patients were divided into two groups on the basis of the with or without loose screws: the loosening group and the non-loosening group. The patient's gender, age, BMI, smoking and diabetes histories, and the operative segment were recorded as the basic information. The Hounsfield unit (HU) value for the BMD of the L1-4 lumbar was measured using computed tomography. The patient's distal one-third of the length of the radius and ulna of the non-dominant forearm was chosen as the site for dual-energy X-ray (DXA) bone density testing. RESULTS: The rate of screw loosening was 13% at a minimum 12 months follow-up. Average forearm BMD (0.461 ± 0.1 vs 0.577 ± 0.1, p < 0.001) and mean HU value (L1-4) (121.1 ± 27.3 vs 155.6 ± 32.2, p < 0.001) were lower in the screw loosening group than those in the non-loosening group. In multivariate logistic regression analysis, the forearm BMD (OR 0.840; 95%CI 0.797-0.886) and HU value (L1-4) (OR 0.952; 95%CI 0.935-0.969) were independent risk factor for screw loosening. The area under the curve (AUC) for the forearm BMD and HU value for prediction of pedicle screw loosening was 0.802 and 0.811. The forearm BMD cut-off for predicting pedicle screw loosening was 0.543 (sensitivity, 0.800; specificity, 0.864). CONCLUSIONS: The forearm BMD was an independent risk factor for loosening of the lumbar pedicle screws. The forearm BMD was a valid predictor of pedicle screw loosening in patients undergoing lumbar fusion, as was the CT HU value.

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

BACKGROUND: 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. METHODS: 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). RESULTS: 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). CONCLUSIONS: 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.