Underwent Pedicle Screw Fixation Research Articles

Unravelling a hidden pathology of a vertebral fracture in a teenage girl

BackgroundAlthough the skeleton remains a common target of primary hyperparathyroidism, the classic bone disease “osteitis fibrosa cystica” is currently rare due to early diagnosis. This case represents severe classic bone manifestations of primary hyperparathyroidism due to delayed diagnosis and delayed medical attention.Case presentationA 19-year-old young female was symptomatically managed for chronic back pain and nonspecific bone pain in the small joints of both hands over 2 months by a general practitioner. The patient had delayed seeking for treatment for 3 months. Later, she was evaluated for tuberculosis, hematological malignancies and rheumatic disorders following a fractured T12 vertebra and underwent pedicle screw fixation. However, clinical examination and investigations, including biochemistry, imaging and histology, ruled out the above conditions. Unfortunately, serum calcium level was not performed at the initial presentation. Later, primary hyperparathyroidism was diagnosed on the basis of moderate hypercalcaemia and elevated intact PTH levels (2064 pg/ml). She had sufficient vitamin D levels and normal kidney function. Her DXA scan revealed severe secondary osteoporosis with the lowest Z score of -8 at the total lumbar spine. Ultrasonography of the thyroid revealed a hypo echoic mass in the left lower neck, and localization studies with technetium-99 m sestamibi and 4D-CT revealed a left inferior parathyroid adenoma (1.6 × 1.5 × 1.6 cm). CT scan also revealed brown tumors in the mandible and vertebrae and diffuse bony changes in the skull, sternum, humerus and vertebrae. Her radiographs revealed subperiosteal bone resorption on the radial aspects of the middle and distal phalanges and brown tumors in both the ulna and fibula. We excluded MEN and other hereditary syndromes in our patient with a personal and family history and with a normal pituitary hormone profile because of poor resources for genetic testing. She underwent parathyroid adenoma excision, and the postoperative period was complicated with hungry bone syndrome, requiring high doses of calcium and active vitamin D supplements. These supplements were gradually weaned off over 6 months, and she recovered with normal biochemical investigations. Histology revealed parathyroid adenoma without malignant features.ConclusionIn developing countries where routine calcium screening is not available, clinicians should be aware of various manifestations of primary hyperparathyroidism to allow diagnosis as soon as possible without delay to prevent further progression, as it is a treatable condition.

Clinical Analysis of Microwave Ablation Combined with Decompression and Pedicle Screw Fixation in the Treatment of Spinal Metastases.

There is still controversy over the choice of treatment for end-stage spinal metastases. With the continuous development of microwave technology in spinal tumors, related studies have reported that microwave combined with techniques such as pedicle screw fixation and percutaneous vertebroplasty can achieve the purpose of tumor ablation, relieving spinal cord compression, enhancing spinal stability, effectively relieving pain, and reducing recurrence rates. This study aimed to analyze the effectiveness of microwave ablation combined with decompression and pedicle screw fixation in the palliative management of spinal metastases with pathological fractures. This retrospective study enrolled 82 patients with spinal metastases and pathological fractures treated between January 2016 and July 2020, with 44 patients undergoing pedicle screw fixation along with laminectomy (fixation group) and the remaining 38 receiving microwave ablation in addition to the treatment provided to group fixation (MWA group). Before surgery, all patients underwent pain assessment using the visual analogue scale (VAS) and evaluation of spinal cord injury using the Frankel classification. After surgery, the patients' prognoses were assessed using the Tomita score, modified Tokuhashi score system, and progression-free survival. Additionally, we compared operative time and blood loss between the two groups. Survival analysis utilized the Kaplan-Meier method with a log-rank test for group comparisons. Paired t-tests and the Mann-Whitney U test were applied to metric and non-normally distributed data, respectively. Neurological function improvement across groups was evaluated using the χ2 test. All patients were followed up for a median duration of 18 and 20 months in the fixation and MWA groups, respectively, with follow-up periods ranging from 6 to 36 months. Statistically significant reductions in postoperative VAS scores were observed in all patients compared with their preoperative scores. The MWA group exhibited reduced blood loss (t = 2.74, p = 0.01), lower VAS scores at the 1- and 3-month follow-ups (t = 2.34, P = 0.02; t = 2.83, p = 0.006), and longer progression-free survival than the fixation group (p = 0.03). Although the operation times in the MWA group were longer than those in the fixation group, this difference was not statistically significant (t = 6.06, p = 0.12). No statistically significant differences were found regarding improvements in spinal cord function between the two groups (p = 0.77). Compared with decompression and pedicle screw fixation for treating spinal metastases with pathological fractures, microwave ablation combined with decompression and pedicle screw fixation showed better outcomes in terms of pain control, longer progression-free survival, and lower blood loss without increasing operative time, which has favorable implications for clinical practice.

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

Retrospective cohort. 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. 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. 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. 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.

Operative Effect Comparison of Flexible Drill Guiding vs. Traditional Drill Guiding Template for Lower Cervical Pedicle Screw Insertion: A Retrospective Analysis.

Accurately inserting pedicle screws is the key point of posterior pedicle screw fixation for lower cervical spine (C3-C7) instability. 3D printing technology can improve the accuracy of screw placement. This study compared the safety of 3D-printed flexible drill guiding template vs. traditional rigid drill guiding template for lower cervical pedicle screw insertion. This was a retrospective study. A total of 34 patients who underwent lower cervical pedicle screw fixation from March 2018 to May 2021 were enrolled in this study, and they were divided into the flexible drill flexible drill group and the traditional drill group. A total of 18 patients in the flexible drill flexible drill group underwent pedicle screw fixation assisted by 3D printed flexible drill guiding templates for the lower cervix, and 16 patients in the traditional drill group underwent pedicle screw fixation assisted by 3D printed regular drill guiding templates for the lower cervix. The length of the incision and intraoperative blood loss during surgery were recorded and compared for the two groups. The grade, deviation of the screw entry point, deviation of the screw medial angle and screw length were measured and compared after surgery for the two groups by independent-sample tests. There was a significant difference in the length of the incision and blood loss between the two groups (P < 0.05). There was a significant difference between the two groups for grade (P = 0.016). The deviation of the screw entry point was 0.65 ± 0.50 mm in the flexible drill group and 0.78 ± 0.83 mm in the traditional drill group. The deviation of the screw medial angle was 2.14 ± 1.78 in the flexible drill group and 4.23 ± 2.51 in the traditional drill group, with a significant difference between the two groups (P < 0.05). Compared with regular guiding techniques, lower cervical pedicle screw placement assisted by multistep navigation templates and flexible K-wires results in less trauma and better safety.

Craniocaudal toggling increases the risk of screw loosening in osteoporotic vertebrae

Background and ObjectiveScrew loosening remains a prominent problem for osteoporotic patients undergoing pedicle screw fixation surgeries but its underlying mechanisms are not fully understood. This study sought to examine the interactive effect of craniocaudal or axial cyclic loading (toggling) and osteoporosis on screw fixation. MethodsQCT-based finite element models of normal (n = 7; vBMD = 156 ± 13 mg/cm3) and osteoporotic vertebrae (n = 7; vBMD = 72 ± 6 mg/cm3) were inserted with pedicle screws and loaded with or without craniocaudal toggling. Among them, a representative normal vertebra (age: 55; BMD: 140 mg/cm3) and an osteoporotic vertebra (age: 64; BMD: 79 mg/cm3) were also loaded with or without axial toggling. The individual and interactive effects of craniocaudal toggling and osteoporosis on screw fixation strength (the force when the pull-up displacement of the screw head reached 1 mm) and bone tissue failure (characterized by equivalent plastic strain) were examined by repeated measure ANOVA. ResultsA significant interactive effect between craniocaudal toggling and osteoporosis on screw fixation strength was detected (p = 0.008). Specifically, craniocaudal toggling led to a marked decrease in the fixation strength (68%, p < 0.05) and stiffness (83%, p < 0.05) only in the osteoporotic vertebrae but had no effect on screw fixation strength and stiffness of the normal vertebrae (p > 0.05). Likewise, most of the bone tissues around the screw in the osteoporotic vertebrae yielded following craniocaudal toggling whereas this result was not seen in the normal vertebrae. The axial toggling had no significant effect on bone tissue failure as well as pedicle screw fixation in normal or osteoporotic vertebrae. ConclusionsCraniocaudal toggling substantially reduces the screw fixation strength of the osteoporotic vertebrae by progressively increasing tissue failure around the screw, and therefore may contribute to the higher rates of screw loosening in osteoporotic compared to normal patients, whereas axial toggling is not a risk factor for pedicle screw loosening in normal or osteoporotic patients.

The effect of pedicle screw instrumentation at a young age on upper thoracic vertebra and canal development

BACKGROUND CONTEXTPedicle screws are widely used in spinal surgeries. Pedicle screw fixation has shown better clinical effects than other techniques by providing steady fixation from the posterior arch to the vertebral body. However, there are several concerns about the impact of pedicle screw instrumentation insertion on vertebral development in young children, including early closure of the neurocentral cartilage (NCC). The effect of pedicle screw insertion in an early age on further growth of the upper thoracic spine is still unclear. PURPOSEThis study aimed to evaluate the impact of pedicle screw insertion on further growth of the upper thoracic vertebra and spinal canal. STUDY DESIGNA retrospective case study. PATIENT SAMPLETwenty-eight patients. OUTCOME MEASUREMENTSX-ray and CT parameters including length, height and area of the vertebrae and spinal canal were manually measured. METHODSTwenty-eight patients who underwent pedicle screw fixation (T1-T6) before the age of 5 years from March 2005 to August 2019 at Peking Union Medical College Hospital were recruited, and records were retrospectively reviewed. Vertebral body and spinal canal parameters were measured at instrumented and adjacent noninstrumented levels and compared using statistical methods. RESULTSNinety-seven segments met the inclusion criteria (average age at instrumentation 44.57 months, range from 23–60 months). Thirty-nine segments had no screws, and 58 had at least one screw. There was no significant difference between the preoperative and final follow-up values of the measurement of vertebral body parameters. No significant difference was observed between the growth rates in levels with or without screws in pedicle length, vertebral body diameter, or spinal canal parameters. CONCLUSIONPedicle screw instrumentation in the upper thoracic spine does not cause a negative effect on the development of the vertebral body and spinal canal in children younger than 5 years old.

Influence of the facet joint angle on facet joint degeneration following pedicle screw fixation without fusion in thoracolumbar fractures.

Posterior approach pedicle screw fixation without fusion is widely used in the treatment of neurologically intact type A3 thoracolumbar fractures. To analyze the influence of the facet joint (FJ) angle on FJ degeneration following posterior approach pedicle screw fixation without fusion in neurologically intact type A3 thoracolumbar fractures. Fifty-eight patients who underwent pedicle screw fixation via the traditional posterior approach (n= 28) or the Wiltse approach (n= 30) were enrolled. A CT scan was performed before fixation and before fixation removal (Within 1.5 to 2 years after fixation) to evaluate the FJs parameters, including FJ inclination (FJI), FJ tropism (FJT), FJ violation, and FJ degeneration grade (FJDG), of three fixed segments and the adjacent segment below the fixed segments. There was no significant difference in FJ violation rate, FJDG deterioration, or FJ angle between the two groups (P> 0.05). FJDG deterioration showed a weak positive correlation with FJI and FJT before fixation, and the angular change in FJI (P< 0.05); and FJT before fixation and the angular change in FJI were risk factors for FJDG deterioration (P< 0.01). The Wiltse approach did not increase the rate of FJDG deterioration and FJs angle changes. However, the FJT before fixation and the angular change in FJI were risk factors for FJDG deterioration.

Comparison of three techniques in the surgical management of metastatic vertebral fracture with posterior wall damage: a retrospective study

BackgroundTo retrospectively compare the safety and efficacy of percutaneous kyphoplasty (PKP), internal fixation (IF), and kyphoplasty combined with internal fixation (KP + IF) in treating metastatic vertebral fracture (MVF) with posterior wall damage.Methods87 patients with MVF with posterior wall damage underwent surgery. In Group PKP, 36 patients underwent PKP; in Group IF, 20 patients underwent pedicle screw fixation; and in Group KP + IF, 31 patients underwent kyphoplasty combined with pedicle screw fixation. Operative time, intraoperative blood loss, clinical and radiological results, and complication rate in each group were evaluated and compared.ResultsSignificant improvement on the VAS, ODI scores, vertebral height and local kyphotic angle (LKA) was noted in each group (P < 0.001). Group PKP and Group KP + IF achieved better pain relief than Group IF (P < 0.05). At postoperative 3 days, Group PKP had better pain relief than Group KP + IF (P < 0.05). At other follow-up time points, there were no differences between Group PKP and KP + IF (P > 0.05). Group KP + IF and Group IF were more efficacious than Group PKP in terms of height restoration and LKA correction (P < 0.05). Group KP + IF had a higher incidence of postoperative complications than Group PKP and Group IF(P < 0.05).ConclusionsPKP was safe and effective in treating MVF with posterior wall damage. It can achieve similar clinical outcomes compared to KP + IF, but associated with less operative time, less blood loss and fewer complications. IF alone should not be the first treatment option for its poorer analgesic effect.

Vertebral Bone Quality Score as a Predictor of Pedicle Screw Loosening following Surgery for Degenerative Lumbar Disease.

Retrospective study. To investigate whether magnetic resonance imaging (MRI)-based vertebral bone quality (VBQ) score can predict pedicle screw loosening in patients who underwent pedicle screw fixation, and to compare which measurement, the VBQ score or the Hounsfield unit (HU) value, is more predictive of pedicle screw loosening. In clinical work, we found that patients with screw loosening had higher VBQ scores. In addition, some studies have found a correlation between VBQ scores and osteoporosis. Patients who were treated with lumbar pedicle screw fixation were reviewed. The VBQ score was measured using MRI scans. The HU value for L1-4 lumbar bone mineral density (BMD) was measured with computed tomography scans. Logistic regression analysis was used to identify factors associated with pedicle screw loosening. Receiver-operating characteristic curve (ROC) analysis was used to evaluate the value of VBQ scores in predicting pedicle screw loosening. A total of 156 patients were included in the final analysis. The pedicle screw loosening rate was 35% (55 of 156 patients). The postoperative low-back pain VAS score was higher in the loosening group (3.0±2.0 vs. 2.4±1.8, P<0.05). The VBQ score was higher in the loosening group than in the non-loosening group (3.28±0.58 vs. 2.82±0.50; P<0.01). In multivariable analysis, non-single segment fixation (OR, 3.992; 95% CI 1.643-9.701; P=0.002), LIV at S1 (OR, 3.378; 95% CI 1.387-8.226; P=0.007), HU value (OR, 0.988; 95% CI 0.976-1.000; P=0.047), and VBQ score (OR, 3.908; 95% CI 1.624-9.405; P=0.002) were factors associated with screw loosening. The areas under the curve (AUCs) for using the VBQ score and HU value to predict pedicle screw loosening were 0.720 and 0.702, respectively. The optimal VBQ score threshold was 3.05 for predicting pedicle screw loosening (sensitivity,0.655; specificity,0.713). The VBQ score was an influential factor associated with lumbar pedicle screw loosening, and a higher VBQ score was significantly correlated with a higher risk of screw loosening. The VBQ score was a better predictor of pedicle screw loosening than the HU value in patients who underwent pedicle screw fixation for degenerative lumbar disease.

Pedicle Screw Placement Aided byC-Arm Fluoroscopy: A "Nevermore without" Technology to Pursue Optimal Spine Fixation.

The surgical technique and the intraoperative technology that support spinal pedicle screw placement have consistently evolved over the past decades to decrease the misplacement rate of pedicle screws. We retrospectively evaluated our case series by analyzing the period 2016-2020. Patients undergoing pedicle screw fixation for cervical, thoracic, or lumbar spine degenerative diseases have been included. Surgery was carried out with the aid of intraoperative 3D C-arm fluoroscopy to assess and optimize screw placement and/or correct possible mispositioning. Each patient underwent a postoperative CT scan. Our aim was to evaluate the safety and accuracy of pedicle screw placement and estimate the variation in mispositioning rates. We carried out 329 surgical procedures, as follows: 70 cervical, 78 thoracic spine, and 181 lumbar spine surgeries. An excellent overall pedicle screw positioning was obtained, with slight differences between the cervical (98.6%), thoracic (100%), and lumbar (98.9%) tracts. Accordingly, only three patients required a revision surgery owing to mispositioning (0.91%). In particular, intraoperative C-arm fluoroscopy significatively improved the accuracy of thoracic screw positioning, as shown by postoperative CT scans. Our experience proves the crucial role of intraoperative C-arm fluoroscopy in pursuing optimal technical results and improving patient outcomes at follow-up.

A Novel Screw Modeling Approach to Study the Effects of Screw Parameters on Pullout Strength.

Screw loosening remains a prominent problem for osteoporotic patients undergoing pedicle screw fixation surgeries and is affected by screw parameters (e.g., diameter, pitch, and thread angle). However, the individual and interactive effects of these parameters on screw fixation are not fully understood. Furthermore, the current finite element modeling of a threaded screw is less computationally efficient. To address these issues, we (1) explored a novel "simulated threaded screw" approach (virtual threads assigned to the contact elements of a simplified screw) and compared its performance with threaded and simplified screws, and (2) examined this approach the individual and interactive effects of altering screw diameter (5.5-6.5 mm), pitch (1-2 mm) and half-thread angle (20-30 deg) on pullout strength of normal vertebrae. Results demonstrated that the "simulated threaded screw" approach equivalently predicted pullout strength compared to the "threaded screw" approach (R2 = 0.99, slope = 1). We further found that the pullout strength was most sensitive to the change in screw diameter, followed by thread angle, pitch, and interactions of diameter*pitch or diameter*angle. In conclusion, the "simulated threaded screw" approach can achieve the same predictive capability compared to threaded modeling of the screw. The current findings may serve as useful references for planning of screw parameters, so as to improve the complication of screw loosening.

Augmentation of Pedicle Screws Using Bone Grafting in Patients with Spinal Osteoporosis.

The aim of the study was to develop a new method of vertebral augmentation based on autologous and allogeneic bone chips to be used in pedicle screw fixation and to compare this method with the technique based on polymethyl methacrylate (PMMA).Materials and MethodsThis prospective non-randomized study included 164 patients with degenerative pathologies or traumatic injuries of the lumbar spine and transitional thoracolumbar segments; 153 of the operated patients were followed up for 18 months. In these patients, radiodensity of the cancellous bone tissue was below 110 HU by the Hounsfield scale. Patients with degenerative spinal disorders underwent pedicle screw fixation using transforaminal interbody fusion; patients with traumatic spinal injuries underwent intermediate pedicle screw fixation, and those with a loss of vertebral body height by >50% underwent anterior fusion.The patients were divided into three groups: in group 1 (n=39), bone tissue augmentation was performed using PMMA; in group 2 (n=21), augmentation was done with bone chips; in group 3 (n=93), no augmentation was performed (control group). The follow-up period was 12 months; cases with fixator breakage or loosening were recorded.ResultsAfter augmentation with PMMA, 11 cases (28.2%) of fixator destabilization were detected. With bone chips, fixator instability developed in 2 patients (9.5%) only, whereas in patients operated without augmentation, the instability was observed in 43 cases (46.2%). With PMMA augmentation, the incidence rate of fixator destabilization did not significantly differ from that in the control group (p=0.0801), while the use of bone chips resulted in a statistically significant decrease of this index compared to the control group (p=0.0023). A logistic regression analysis confirmed the superiority of the developed method over the PMMA-based vertebral augmentation.ConclusionThe use of bone chips for vertebral augmentation provides a statistically significant decrease in the incidence of pedicle screw fixator destabilization in the post-operative period. By reducing the risk of proximal loosening and eliminating the risk of bone cement drainage into the spinal canal and vascular bed, the proposed method may become especially effective in patients with impaired bone density.

Novel MIS 3D NAV Single Step Pedicle Screw System (SSPSS): Workflow, Accuracy and Initial Clinical Experience.

Study Design:Prospective case series.Objective:SSPSS (single step pedicle screw system) was developed for minimally invasive spine surgery. We performed this study to report on safety, workflow, and our initial clinical experience with this novel technique.Methods:The prospective study was conducted on patients who underwent pedicle screw fixation between October 2017 and April 2018 using a novel single step 3D navigated pedicle screw system for MIS. Outcome measurements were obtained from intraoperative computerized tomography. The images were evaluated to determine pedicle wall penetration. We used a grading system to assess the severity of the pedicle wall penetration. Breaches were classified as grade 1 (<2 mm), grade 2 (2-4 mm), or grade 3 (<4 mm), 1 and as cranial, caudal, medial, and lateral.Results:Our study includes 135 screws in 24 patients. SSPSS eliminated K-wires and multiple steps traditionally necessary for MIS pedicle screw insertion. The median time per screw was 2.45 minutes. 3 screws were corrected intraoperatively. Pedicle wall penetration occurred in 14 screws (10%). Grade 1 breaches occurred in 4 screws (3%) and grade 2 breaches occurred in 10 screws (7%). Lateral breaches were observed more often than medial breaches. The accuracy rate in our study was 90% (Grade 0 breach). No revision surgeries were needed and no complications occurred.Conclusions:Our study suggests that SSPSS could be a safe, accurate, and efficient tool. Our accuracy rate is comparable to that found in the literature.

Accuracy of Freehand versus Navigated Thoracolumbar Pedicle Screw Placement in Patients with Metastatic Tumors of the Spine.

ObjectiveTo compare the accuracy and breach rates of freehand (FH) versus navigated (NV) pedicle screws in the thoracic and lumbar spine in patients with metastatic spinal tumors. MethodsA retrospective review of adult patients who underwent pedicle screw fixation in the thoracic or lumbar spine for metastatic spinal tumors between 2012 and 2018 was conducted. Breaches were assessed based on the Gertzbein and Robbins classification and only screws placed >4 mm outside of the pedicle wall (lateral or medial) were considered breached. ResultsA total of 62 patients received 547 pedicle screws (average 8 per patient) – 34 patients received 298 pedicle screws in the FH group and 28 patients received 249 screws in the NV group. There were 40/547 breaches, corresponding to a breach and accuracy rate of 7.3% and 92.7%, respectively. The breach rate was 9.7% in the FH group and 4.4% in the NV group (chi-squared test, p=0.017); this corresponded to an accuracy rate of 90.3% and 95.6%, respectively. Only one patient from the overall cohort (in the FH group) required revision surgery due to a medial breach abutting the spinal cord (1.6% of all patients; 2.9% of FH patients); no patient suffered organ, vessel, or neurological injury from screw breaches. ConclusionNavigated pedicle screw placement in patients with metastatic spinal tumors has a significantly higher radiographic accuracy compared to the FH technique. However, the revision surgery was low and no patient suffered from clinically-relevant breach. Navigation also offers the advantage of real-time localization of spinal tumors and aids in targeting and resection of these lesions.

Perforation Rate of Pedicle Screws Using Hybrid Operating Room Combined With Intraoperative Computed Tomography Navigation for Adolescent Idiopathic Scoliosis: Impact of Distance From the Reference Frame and Other Risk Factors.

Retrospective observational cohort study. Evaluate the perforation rate of pedicle screw (PS) insertion using a hybrid OR combined with intraoperative computed tomography (CT) navigation (hybrid navigation) for adolescent idiopathic scoliosis (AIS) and determine the predictors of misplacement specific to hybrid navigation. Hybrid navigation provides intraoperative three-dimensional fluoroscopic imaging of a quality similar to that of CT. Hybrid navigation is now being used in AIS treatment. However, few reports exist on the perforation rate and predictors of PS perforation using hybrid navigation for AIS. Thirty-eight consecutive patients (34 female and 4 male; mean age: 16.2 years) with AIS who had undergone PS fixation using hybrid navigation were analyzed. PS perforation was evaluated using intraoperative CT after PS insertion. The perforation rate for each level from the anchor reference frame (RF) was measured and compared. We examined for predictors of screw misplacement using baseline patient parameters, instrumented vertebral level, PS insertion order, and vertebral body distance from the RF. Eighteen major perforations (Grade 2 or Grade 3) were recorded among 531 screw insertions (3.4%). The major perforation rate did not increase remarkably until the distance from the RF was 5 vertebral bodies, after which it increased significantly (2.2% vs. 18.4%, P = 0.03). Thirteen patients experienced at least 1 perforation. The subjects with perforations were all female and significantly shorter than those without. Multivariate analysis revealed distance from the RF (+1 vertebra; odds ratio 1.44, P = 0.003) as a predictor of major perforation. The rate of major perforation after PS insertion using hybrid navigation for AIS was relatively low. However, no more than 7 vertebral bodies should be instrumented in a single CT scan to reduce the risk of major perforations. Special attention is also needed for female patients of shorter stature. 3.

Does Main Curve Flexibility Affect Screw Insertion Accuracy Using a CT-based Navigation System in Adolescent Idiopathic Scoliosis Surgery?

A retrospective single-center and single-surgeon study. This study investigated the screw perforation rate according to main curve flexibility in pedicle screw fixation using a computed tomography (CT) guidance for adolescent idiopathic scoliosis (AIS). The authors have been using a CT-based navigation system during pedicle screw insertion for AIS to avoid serious neurovascular or visceral structure injury but suspect that high main curve flexibility may account for some breaches. Seventy-two consecutive patients with AIS Lenke type 1 or 2 who had undergone pedicle screw fixation using a CT-based navigation system between February 2008 and April 2018 were retrospectively reviewed. The authors evaluated the perforation rate of pedicle screws inserted into the main thoracic curve between the upper-end and lower-end vertebrae for factors associated with screw violations using multivariate logistic regression mixed models. A total of 723 pedicle screws were inserted into the T4-T12 vertebrae with the aid of CT-based navigation. The respective grade 3 perforation rates according to main curve flexibility were 0%-30%: 3.2%; 30%-55%: 1.1%; 55%-75%: 5.2%; and 75%-100%: 5.5%. Main curve flexibility of ≥55% was significantly associated with grade 3 screw perforations (P=0.02). Main curve flexibility of ≥55% was significantly related to screw violation in AIS surgery. Greater care is thus advised for screw insertion using CT navigation in AIS with main curve flexibility ≥55%.

Hounsfield units value is a better predictor of pedicle screw loosening than the T-score of DXA in patients with lumbar degenerative diseases.

To compare the performance of using Hounsfield units (HU) value derived from computed tomography and T-score of dual-energy X-ray absorptiometry (DXA) to predict pedicle screw loosening. We reviewed 253 patients aged ≥ 50years undergoing pedicle screw fixation for lumbar degenerative diseases (LDD). The evaluation of screw loosening: radiolucent zones of ≥ 1mm thick in X-ray. The criterion for osteoporosis: the lowest T-score ≤ - 2.5. The average HU value of L1-L4 was used to represent lumbar bone mineral density (BMD). The area under receiver operating characteristics curve (AUC) was used to evaluate the performance of predicting screw loosening. One patient underwent reoperation for screw loosening at 9months follow-up. At 12months follow-up, the loosening rate was 30.6% (77/252) in the remaining 252 patients. Osteoporotic patients had higher loosening rate than non-osteoporotic patients (39.3% vs. 25.8%, P = 0.026). The T-score showed no significant difference between loosening group and non-loosening group (- 2.1 ± 1.5 vs. - 1.7 ± 1.6, P = 0.074), and so is the lowest lumbar BMD of DXA (0.83 ± 0.16g/cm2 vs. 0.88 ± 0.19g/cm2, P = 0.054). The HU value was lower in the loosening group (106.8 ± 34.4 vs. 129.8 ± 45.7, P < 0.001). The HU value (OR, 0.980; 95%CI 0.968-0.993; P = 0.002) was the independent influencing factor of screw loosening. The AUC of predicting screw loosening was 0.666 (P < 0.001) for HU value and 0.574 (P = 0.062) for T-score. HU value is a better predictor of pedicle screw loosening than T-score of DXA in patients aged ≥ 50years with LDD. We should not only focus on the DXA measurements when making surgical plans concerning lumbar fixation. These slides can be retrieved under Electronic Supplementary Material.

The efficacy and safety of multiple-dose intravenous tranexamic acid in reducing perioperative blood loss in patients with thoracolumbar burst fracture

ObjectiveTo evaluate the efficacy and safety of tranexamic acid (TXA) for single-segment thoracolumbar burst fracture without neurologic injury underwent pedicle screw fixation via Wiltse approach. Patients and methodsWe identified 264 patients with single-segment thoracolumbar burst fracture without neurologic injury underwent pedicle screw fixation via Wiltse approach (January 2016-June 2019) at a single center. The cohort was separated into three groups. Group A received 20 mg/kg TXA at 5 min before skin incision and 16 h after first dose; Group B received 20 mg/kg TXA at 5 min before skin incision; Group C received NS at each same time point. The outcomes were evaluated by hidden blood loss (HBL), total blood loss (TBL), intraoperative blood loss (IBL), transfusion rate, maximum hemoglobin (Hb) drop, prethrombotic state molecular markers, liver and renal function, coagulation function, inflammatory factor and adverse events. ResultsThe HBL, TBL and maximum Hb drop were significantly lower in Group A than those of Group B and Group C, while the difference between Group B and Group C was statistically significant. The IBL was significantly lower in Group A and Group B than that of Group C. However, there was no significantly difference among the three groups in live and renal function, coagulation function, prethrombotic state molecular markers, transfusion rate and complications during the perioperative period. There was significantly lower level of interleukin-6 (IL-6) in Group A than Group C at the day after surgery, and lower level of C-reactive protein (CRP) at the third day after surgery. ConclusionsIntravenous TXA used in the treatment of thoracolumbar burst fracture underwent pedicle screw fixation via Wiltse approach is effective and safe in decreasing perioperative blood loss. The two-dose TXA regimen can further reduce blood loss and alleviate post-operative inflammation response, without affecting prethrombotic state molecular marks and without increasing the risk of complications.

Accuracy and reliability of spinal navigation: An analysis of over 1000 pedicle screws

PurposeTo estimate the rate of pedicle screw malpositioning associated with placing pedicle screws using intraoperative computed tomography (CT)-guided spinal navigation. MethodsWe analysed the records of 219 patients who underwent pedicle screw fixation using O-arm-based navigation. Screw placement accuracy was evaluated on intraoperative CT scans acquired after pedicle screw insertion. Breaches were graded according to the Gertzbein classification (grade 0–III). ResultsOf 1152 pedicle screws included, 47 had pedicle violations noted on intraoperative CT. Pedicle screw violation was noted for 17 of 241 screws placed in the cervical spine (overall breach rate, 7.05%; 3.73% and 3.3% with grade I and II, respectively), for 11 of 300 screws placed in the thoracic spine (overall breach rate, 3.67%; 2%, 1%, and 0.67% with grade I, II, and III, respectively), and for 22 of 611 screws placed in the lumbar spine (overall breach rate, 3.6%; 2.29% and 0.82% with grade I and II, respectively). The rate of accuracy of pedicle screw fixation was 93%, 96.33%, and 96.4% for the cervical, thoracic, and lumbar spine, respectively. ConclusionsUsing O-arm-based intra-operative three-dimensional scans for navigation can improve the reliability, accuracy, and safety of pedicle screw placement, reducing the risk for reoperation and hospitalization due to implant-related complications. Further improvement may be achieved by adequate consideration of potential sources of errors.

Assessment of patients' psychological state and self-efficacy associated with postoperative constipation after thoracolumbar fracture surgery.

ObjectiveWe aimed to explore the relationship among the duration of constipation at 30 days after thoracolumbar fracture surgery, self-efficacy, and anxiety or depression in patients with constipation after thoracolumbar fracture surgery.MethodsIn this descriptive correlational study, 108 patients with thoracolumbar fracture undergoing pedicle screw fixation surgery were recruited from January 2015 to May 2017 in our hospital. From the day of surgery, we conducted a 1-month follow-up investigation. We evaluated the pattern of defecation, stool consistency, and incidence of defecation-related problems using a structured interview. Clinical data were obtained using a patient intake form, and we applied the Health Behavior Self-Efficacy Scale (HBSES), and Hospital Anxiety and Depression Scale (HADS).ResultsApproximately 83.3% of patients experienced postoperative constipation, and most exhibited normal defecation by postoperative day 13. Self-efficacy and anxiety and depression were graded at a medium level in most patients. The average HBSES score was 74.39 ± 11.08, and the mean HADS score was 7.97 ± 4.08. The duration of postoperative constipation was negatively correlated with self-efficacy and positively associated with anxiety or depression.ConclusionsSelf-efficacy, anxiety, and depression are important sociopsychological factors associated with the duration of postoperative constipation.