Spinal Fixation Surgery Research Articles

Comparative evaluation of different doses of gabapentin and celecoxib as multimodal oral analgesia in patients of spine fixation surgery

Comparative evaluation of different doses of gabapentin and celecoxib as multimodal oral analgesia in patients of spine fixation surgery

Complications after spinal fixation surgery for osteoporotic vertebral collapse with neurological deficits: Japan Association of Spine Surgeons with ambition multicenter study

BackgroundThere have been few reports on the incidence and risk factors of the complications after spinal fixation surgery for osteoporotic vertebral collapse (OVC) with neurological deficits. This study aimed to identify the incidence and risk factors of the complications after OVC surgery. MethodsIn this retrospective multicenter study, a total of 403 patients (314 women and 89 men; mean age 73.8 years) who underwent spinal fixation surgery for OVC with neurological deficits between 2005 and 2014 were enrolled. Data on patient demographics were collected, including age, sex, body mass index, smoking, steroid use, medical comorbidities, and surgical procedures. All postoperative complications that occurred within 6 weeks were recorded. Patients were classified into two groups, namely, complication group and no complication group, and risk factors for postoperative complications were investigated by univariate and multivariate analyses. ResultsPostoperative complications occurred in 57 patients (14.1%), and the most common complication was delirium (5.7%). In the univariate analysis, the complication group was found to be older (p = 0.039) and predominantly male (p = 0.049), with higher occurrence rate of liver disease (p = 0.001) and Parkinson's disease (p = 0.039) compared with the no-complication group. In the multivariate analysis, the significant independent risk factors were age (p = 0.021; odds ratio [OR] 1.051, 95% confidence interval [CI] 1.007–1.097), liver disease (p < 0.001; OR 8.993, 95% CI 2.882–28.065), and Parkinson's disease (p = 0.009; OR 3.636, 95% CI 1.378–9.599). ConclusionsComplications after spinal fixation surgery for OVC with neurological deficits occurred in 14.1%. Age, liver disease, and Parkinson's disease were demonstrated to be independent risk factors for postoperative complications.

MORTALITY AND ITS ASSOCIATED FACTORS IN PATIENTS WITH SPINAL CORD INJURIES AT PARAPLEGIC CENTER PESHAWAR, PAKISTAN

OBJECTIVE: to determine mortality and its associated factors in patients with spinal cord injuries (SCI), presenting to Paraplegic Center Peshawar, Pakistan. METHODS: In this retrospective study, clinical records of SCI patients, admitted to Paraplegic Center from January 2011 to March 2017 were evaluated. SCI patients who died during this period, irrespective of their age, gender, duration of SCI and number of readmissions were included in study. Demographic information, clinical characteristic and complications in eligible patients were recorded and analyzed. RESULTS: Out of 62 patients, 46 (74.2%) were males. Mean age of patients was 41.7±17.3 years. Twenty-two (35.5%) patients aged ≤30 years &amp; 20 (32%) patients aged &gt;50 years. The most common cause of SCIs was fall from height (n=23, 37.1%), followed by road traffic accident (n=17, 27.4%) and firearm injury (n=11, 17.7%). About 51.6% of patients (n=32) had complete thoracic paraplegia, 30.6% (n=19) had complete cervical tetraplegia and 8.1% (n=5) had incomplete cervical tetraplegia. Complications and co-morbid conditions included pressure ulcers (n=53; 85.5%), limb fractures (n=7 11.3%), deep venous thrombosis (n=3; 4.8%), hepatitis (n=2; 3.2%) and injury to brachial plexus (n=1; 1.6%). Twenty-two (35.5%) patients underwent spine fixation surgery while forty (64.5%) patients were managed conservatively. Majority of the patients (n=51, 82.3%) died within the first year of SCI. CONCLUSION: Relatively younger patients were predominant and complete thoracic paraplegia was the commonest SCI level. Presence of pressure ulcers, limb fractures and deep venous thrombosis in patients with SCI were major contributing factors to morbidity leading to mortality in our patients.

Is there a place for the use of activator poles in rehabilitation following spinal surgery?

Purpose: Following spinal fixation surgery, it is generally agreed that an upright posture is better for a patient and reduces the risk of revision surgery if this is maintained. ‘Activator Poles’ (AP, a type of walking pole) can be used to encourage this upright posture; however to our knowledge no research has compared the use of AP's to other walking aids. The purpose of this pilot study was to explore whether using AP's encourages a more upright posture in comparison to other walking aids.

Prospective Multicenter Study of a Multistep Screw Insertion Technique Using Patient-Specific Screw Guide Templates for the Cervical and Thoracic Spine.

A prospective clinical study of a multistep screw insertion method using a patient-specific screw guide template system (SGTS) for the cervical and thoracic spine. To evaluate the efficacy of SGTS for inserting screws into the cervical and thoracic spine. Posterior screw fixation is a standard procedure for spinal instrumentation; however, screw insertion carries the risk of injury to neuronal and vascular structures. Preoperative bone images of the computed tomography (CT) scans were analyzed using 3D/multiplanar imaging software, and the screw trajectories were planned. Plastic templates with screw-guiding structures were created for each lamina using 3D design and printing technology. Three types of templates were made for precise multistep guidance, and all the templates were specially designed to fit and lock onto the lamina during the procedure. In addition, plastic vertebra models were generated, and preoperative screw insertion simulation was performed. This patient-specific SGTS was used to perform the surgery, and CT scanning was used to postoperatively evaluate screw placement. Enrolled to verify this procedure were 103 patients with cervical, thoracic, or cervicothoracic pathologies. The SGTS were used to place 813 screws. Preoperatively, each template was found to fit exactly and to lock onto the lamina of the vertebra models. In addition, intraoperatively, the templates fit and locked onto the patient lamina, and the screws were inserted successfully. Postoperative CT scans confirmed that 801 screws (98.5%) were accurately placed without cortical violation. There were no injuries to the vessels or nerves. The multistep, patient-specific SGTS is useful for intraoperative pedicle screw (PS) navigation in the cervical and thoracic spine. This method improves the accuracy of PS insertion and reduces the operating time and radiation exposure during spinal fixation surgery. 3.

Total intravenous anaesthesia versus volatile induction and maintenance anaesthesia for controlled hypotension in lumbar spine fixation surgery: Comparative clinical study

Background: Controlled hypotension during general anesthesia aims to lower the mean arterial blood pressure (MAP)to values between 55 and 65 mmHg in patients with normal blood pressure, with the goal of significantly reducing blood loss by maintaining it at this level throughout the operation process. Controlled hypotension is frequently used for obtaining better exposure during spine surgery as small bleeding areas can produce better surgical field visibility and result in decreased time of surgery.Objective: This study was done to compare the efficacy and safety of TIVA and VIMA to induce hypotensive technique during spine surgery, with attention on the amount of blood loss, blood transfusion, hemodynamics, time of recovery and postoperative nausea and vomiting. Patients and Methods: This study included 40 patients of both sex, admitted for lumbar spine fixation surgery carried out at Al- Azhar University Hospitals (El-Hussein and Bab El-Sharia). They were randomly allocated into two equal groups, 20 patients each (n= 20): Group I (TIVA); Total intravenous anaesthesia using (fentanyl and propofol). Group II (VIMA); Volatile induction and maintenance anesthesia (Inhalational anaesthesia) using (fentanyl and sevoflurane). Results: The following parameters were assessed between the 2 groups: Hemodynamics (HR, SBP, DBP and MAP), SPO2 and ET CO2 were continuously monitored and recorded at 15 min interval. Intraoperative blood loss, blood transfusion, duration of surgery, time of recovery and postoperative nausea and vomiting were monitored in all patients. Conclusion: this study showed that both TIVA and VIMA were effective in producing controlled hypotension for lumbar spinal fixation surgery. However, only TIVA was beneficial, allowing properly controlled hypotension, minimized intraoperative bleeding, and improved surgical field visibility compared to VIMA.

Total intravenous anaesthesia versus volatile induction and maintenance anaesthesia for controlled hypotension in lumbar spine fixation surgery: Comparative clinical study

Background: Controlled hypotension during general anesthesia aims to lower the mean arterial blood pressure (MAP)to values between 55 and 65 mmHg in patients with normal blood pressure, with the goal of significantly reducing blood loss by maintaining it at this level throughout the operation process. Controlled hypotension is frequently used for obtaining better exposure during spine surgery as small bleeding areas can produce better surgical field visibility and result in decreased time of surgery.Objective: This study was done to compare the efficacy and safety of TIVA and VIMA to induce hypotensive technique during spine surgery, with attention on the amount of blood loss, blood transfusion, hemodynamics, time of recovery and postoperative nausea and vomiting. Patients and Methods: This study included 40 patients of both sex, admitted for lumbar spine fixation surgery carried out at Al- Azhar University Hospitals (El-Hussein and Bab El-Sharia). They were randomly allocated into two equal groups, 20 patients each (n= 20): Group I (TIVA); Total intravenous anaesthesia using (fentanyl and propofol). Group II (VIMA); Volatile induction and maintenance anesthesia (Inhalational anaesthesia) using (fentanyl and sevoflurane). Results: The following parameters were assessed between the 2 groups: Hemodynamics (HR, SBP, DBP and MAP), SPO2 and ET CO2 were continuously monitored and recorded at 15 min interval. Intraoperative blood loss, blood transfusion, duration of surgery, time of recovery and postoperative nausea and vomiting were monitored in all patients. Conclusion: this study showed that both TIVA and VIMA were effective in producing controlled hypotension for lumbar spinal fixation surgery. However, only TIVA was beneficial, allowing properly controlled hypotension, minimized intraoperative bleeding, and improved surgical field visibility compared to VIMA.

Pedicle Screw Placement Using Augmented Reality Surgical Navigation With Intraoperative 3D Imaging: A First In-Human Prospective Cohort Study.

Prospective observational study. The aim of this study was to evaluate the accuracy of pedicle screw placement using augmented reality surgical navigation (ARSN) in a clinical trial. Recent cadaveric studies have shown improved accuracy for pedicle screw placement in the thoracic spine using ARSN with intraoperative 3D imaging, without the need for periprocedural x-ray. In this clinical study, we used the same system to place pedicle screws in the thoracic and lumbosacral spine of 20 patients. The study was performed in a hybrid operating room with an integrated ARSN system encompassing a surgical table, a motorized flat detector C-arm with intraoperative 2D/3D capabilities, integrated optical cameras for augmented reality navigation, and noninvasive patient motion tracking. Three independent reviewers assessed screw placement accuracy using the Gertzbein grading on 3D scans obtained before wound closure. In addition, the navigation time per screw placement was measured. One orthopedic spinal surgeon placed 253 lumbosacral and thoracic pedicle screws on 20 consenting patients scheduled for spinal fixation surgery. An overall accuracy of 94.1% of primarily thoracic pedicle screws was achieved. No screws were deemed severely misplaced (Gertzbein grade 3). Fifteen (5.9%) screws had 2 to 4 mm breach (Gertzbein grade 2), occurring in scoliosis patients only. Thirteen of those 15 screws were larger than the pedicle in which they were placed. Two medial breaches were observed and 13 were lateral. Thirteen of the grade 2 breaches were in the thoracic spine. The average screw placement time was 5.2 ± 4.1 minutes. During the study, no device-related adverse event occurred. ARSN can be clinically used to place thoracic and lumbosacral pedicle screws with high accuracy and with acceptable navigation time. Consequently, the risk for revision surgery and complications could be minimized. 3.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P73. Economic study: a cost-effectiveness study of an intraoperative compared with a preoperative image-guided system in spine surgery fixation. Analysis of 10years of experience

BACKGROUND CONTEXT Spinal navigation and image-guided system (IGS) are, up to now, well establish technologies, and thanks to their excellent results their spread is growing. In the latest years many publications and meta-analyses demonstrate their accuracy and safety, and even more center adopted IGS in daily activity. However, the acquisition and maintenance costs of these systems are high, and not all the hospital and clinics can effort its purchase. In an era when health expenditure is rising exponentially, cost-effectiveness analyses are mandatory to responsibly manage the scarce health care resources and to define if this technology is economically sustainable and which criteria must be respect to justify its acquisition. PURPOSE The purpose of the present study was to perform a detailed cost-effectiveness analysis to determine the value of a navigation system coupled with intra-operative 3D imaging in adult spinal surgery analyzed thought a micro costing approach in a period of 10years. STUDY DESIGN/SETTING Retrospective cost-effectiveness study. PATIENT SAMPLE Patients operated on our surgical department between 2003 and 2013. METHODS A retrospective cost-effectiveness study was conducted to analyze the overall costs of a population of patients admitted to our Neurosurgical department for spine fixation surgery. In the present study the authors have analyzed the entire population of patients treated for spinal instrumentation with the aid of an IGS system from January 2003 to March 2013. The cost-effectiveness study compared two different type of spinal navigation: system based on a preoperative CT scan (from January 2003 to April 2009 – group I) and the intraoperative CT like scan system (from April 2009 to March 2013 – group II). The economic evaluation is conducted from a hospital perspective. Costs of the two procedures are measured and valued using a microcosting approach. All costs incurred by the hospital are collected from the hospital's accounting service. The evaluation took into consideration all of the phases, from preadmission testing to discharge. Cost of the complications are considered and analyzed as well. RESULTS The study includes 499 patients with a total of 2,542 screws inserted with IGS. Baseline data were similar for the two groups, as were hospitalization and complications. The full cost of the two procedures was analysed: mean cost with intraoperative CT scan system procedure was 6.545 € (±525.9) and 6.853 (±564.3) with preoperative image-guided system. The screws' accuracy were respectively 98.5% and 96.1%. Higher costs were identified for human resources, disposable and implanted materials (more than 1.000 €); in particular, cost of human source were higher for the use of preoperative scan. The higher total cost of the procedure with preoperative scan is related for the major part to the cost of CT scan (preoperative for navigation and postoperative for control). CONCLUSIONS The results of our study show a cost difference that is not statistically significant between the two procedures. However, the use of the intraoperative CT scan system suggests an economic advantage in a long-term point of view. It consent to reduce surgical time and complications bringing to a better clinical result; consent an economics saving in term of human resource and number and type of radiological imaging. A break-even point is estimated after almost 150 procedures. Moreover, nowadays this system is used for more than only screws insertion reducing the financial impact of this technology on the hospital.

Postoperative deep wound infection in posterior spinal fixation surgeries: Does it affect the clinicoradiological outcome? - At a minimum follow-up of 2 years

Background: Incidence of postoperative deep wound infection (PODWI) after lumbar surgery varies from 2.1% to 6.7%.Studies looking into the effect of postoperative infection on functional recovery of the patient have thrown conflicting results. The aim of this study is to evaluate 2-year functional and radiological outcome of patients with PODWI. This was a retrospective, matched cohort study. Materials and Methods: A total of 23 patients developing acute PODWI (

Anaesthetic Management of a Morbidly Obese Patient in Prone Position for Spine Fixation Surgery

Anaesthetic Management of a Morbidly Obese Patient in Prone Position for Spine Fixation Surgery

Clinical outcome of posterior fixation surgery in patients with vertebral metastasis of lung cancer.

Vertebral metastasis of non-small-cell lung cancer (NSCLC) often leads to neurological paralysis, with deterioration of the patients' activities of daily living (ADL). Surgical treatments for the symptoms are unlikely to be recommended due to the poor prognosis of patients with advanced NSCLC. The aim of the present study was to retrospectively evaluate the clinical outcome of posterior spinal fixation surgery in patients with neurological paralysis resulting from vertebral metastasis of NSCLC. Between April, 2007 and March, 2012, 4 patients (3 men and 1 woman; median age, 56.5 years) underwent fixation surgery at the Shiga University of Medical Science Hospital (Otsu, Japan). The mean preoperative Tokuhashi and Tomita scores of the patients were high (8.25 and 7.0, respectively). However, the Frankel grade functional score and performance status of the patients improved following fixation surgery, after which all patients received chemoradiotherapy. Postoperatively, the median paralysis-free time was 41 months (range, 17-42 months) and the median survival time was 42.5 months (range, 22-43 months). According to the functional scores, the patients had a poor prognosis, which may have been a contraindication for fixation surgery. In these cases, however, surgical treatment improved the patients' ADL and increased the likelihood of receiving anticancer therapy, contributing to the prolongation of survival. Therefore, fixation surgery may be beneficial for patients with neurological paralysis following vertebral metastasis of advanced NSCLC.

Failed Back Surgery Syndrome: Evaluation with Magnetic Resonance Imaging

Failed Back Surgery Syndrome (FBSS) is a generalized term used to describe varied spinal symptoms of patients who have had unsuccessful results after spinal surgery. The treatment of FBSS is challenging and varies from conservative management to reoperation. Imaging plays a crucial role in identifying the cause and helps to guide the appropriate therapy. Contrast enhanced Magnetic Resonance Imaging (MRI) with its superior resolution is the imaging modality of choice. To evaluate the spectrum of imaging findings on postoperative MRI in FBSS. A total of 30 postoperative symptomatic patients of FBSS were included in this cross-sectional study. Of these, 26 had undergone surgery for degenerative disc disease and four had spinal fixation surgery for spondylolisthesis or trauma. Patients were subjected to detailed clinical examination. All patients underwent MRI which was done on 1.5 Tesla scanner with standard sequences in all planes. Contrast was administered in all cases. Non Contrast Computed Tomography (NCCT) scan was done in patients with metallic implants to better delineate the placement of the implant. Patients with contraindication to MRI scanning were excluded from the study. Of the total 30 cases (23 males and seven females) of FBSS that were evaluated with contrast enhanced MRI of the spine, 16 patients had recurrent/residual disc herniation, six had epidural scar tissue, three patients had recurrent disc herniation and scar tissue, two had evidence of post surgery arachnoiditis, two patients had postoperative discitis and one patient had implant mal alignment. Eight patients underwent reoperation for recurrent disc herniation and one patient for implant malalignment after imaging. MRI is the modality of choice for evaluating the postoperative spine. It helps to identify the cause and guide the appropriate treatment.

Evaluation of neurotrauma in motorcycle-related accidents at a tertiary hospital in Egypt

Background Although traffic laws in Egypt obligate drivers to wear helmets, they are not strictly followed, resulting in an increased incidence of neurotrauma during accidents. Objective The aim of the present study was to evaluate head and spine injuries as a result of motorcycle accidents in 1 year. Patients and methods This study was conducted in the Neurosurgical Emergency Department of Cairo University Hospitals. Only motorcycle-related neurotrauma patients were included. Demographic data, types of lesions inflicted, operations and procedures carried out, hospital stay, and outcome were investigated by analyzing admission files and operation records. The results were then compared with the published literature. Results Out of 117 patients, there were 93% males and 7% females. The age group 20–40 years represented 61.5% of the cases. Extradural hematoma was present in 42 (36%) cases, fissure fracture and base of skull fracture in 64%, brain contusion in 29%, and spine fracture in four (0.034%). Helmeted drivers represented only 9.5% of the patients. Thirty-nine percent of patients had other associated injuries than of head and spine. Operations were performed on 45 (38.5%). Nearly half of the operation procedures comprised evacuation of extradural hematoma. Others included elevation of depressed fracture, frontal sinus repair, decompressive craniotomy, and spinal fixation surgeries. Hospital stay ranged from 2 to 28 days with an average of about 4.5 days; furthermore, 22.2% of the victims became handicapped and dependent. Conclusion Following safety measures during motorcycling significantly reduces morbidity and mortality at time of accidents. Although these patients have a short median hospital stay but surgery rates are obviously high. Follow-up for victims may reveal other potential burdens and help in the reintegration of society.

Late failure of posterior fixation without bone fusion for vertebral metastases.

ABSTRACTOBJECTIVE: To verify the frequency of late radiological com-plications in spinal fixation surgeries performed without fu-sion in oncological patientsMETHODS: This is a retrospective analysis analysing failure in cases of non-fused vertebral fixation in an oncology reference hospital between 2009 and 2014. Failure was defined as implant loosening or bre-akage, as well as new angular or translation deformitiesRESULTS: One hundred and five cases were analyzed. The most common site of primary tumor was the breast and the most common place of metastasis was the thoracic spine. The average follow-up was 22.7 months. Nine cases (8%) of failure were reported, with an average time until failure of 9.5 months. The most common failure was implant loosening. No case required further surgeryCONCLUSION: The occurrence of failure was not different than that reported for fused cases. The time interval until failure was higher than the median of survival of the majority (88%) of cases. Level of Evidence IV, Therapeutic Study.

β-Type titanium alloys for spinal fixation surgery with high Young’s modulus variability and good mechanical properties

Along with a high strength, ductility, and work hardening rate, a variable Young’s modulus is crucial for materials used as implant rods in spinal fixation surgery. The potential in this context of Ti–(9,8,7)Cr–0.2O (mass%) alloys is reported herein. The microstructural and mechanical properties of the alloys were systematically examined as a function of their chromium content, and the ion release of the optimized alloy was investigated to assess its suitability as an implant material. In terms of the deformation-induced ω-phase transformation required for a variable Young’s modulus, the balance between β-phase stability and athermal ω-phase content is most favorable in the Ti–9Cr–0.2O alloy. In addition, this composition affords a high tensile strength (>1000MPa), elongation at break (∼20%), and work hardening rate to solution-treated (ST) samples. These excellent properties are attributed to the combined effects of deformation-induced ω-phase transformation, deformation twinning, and dislocation gliding. Furthermore, the ST Ti–9Cr–0.2O alloy proves resistant to metal ion release in simulated body fluid. This combination of a good biocompatibility, variable Young’s modulus and a high strength, ductility, and work hardening rate is ideal for spinal fixation applications. Statement of significanceExtensive efforts have been devoted over the past decades to developing β-type titanium alloys with low Young’s moduli for biomedical applications. In spinal fixation surgery however, along with excellent mechanical properties, the spinal-support materials should possess high Young’s modulus for showing small springback during surgery to facilitate manipulation but low Young’s modulus close to bone once implanted to avoid stress shielding. None of currently used metallic biomaterials can satisfy these abovementioned requirements. In the present study, we have developed a novel alloy, Ti–9Cr–0.2O. Remarkably variable Young’s modulus and excellent mechanical properties can be achieved in this alloy via phase transformations and complex deformation mechanisms, which makes the Ti–9Cr–0.2O preferred material for spinal fixation surgery.

Comparison of Analgesic Effects of Epidural Infusion of Fentanyl and Fentanyl-bupivacaine in Spine Surgery: A Randomized Clinical Trial Study

Background & Aim: Although most patients experience severe pain after major spinal fixation surgery, little attention has been paid to control it with a multi-modal approach. The aim of this study is to select appropriate method of pain management after spinal surgery. Methods & Materials/Patients: This study was a randomized clinically controlled trial in candidates of spondylolisthesis and spinal fixation surgery under general anesthesia. 90 patients were divided into three groups, as follows: 1) Intervention group of epidural fentanyl (F): patient-controlled analgesia (PCA) pump infused 100 µg of fentanyl and 98cc of normal saline at the rate of 3-5 ml/h in the epidural space via an epidural catheter placed by surgeon 2) Intervention group of epidural fentanyl-bupivacaine (FB): PCA pump infused 100 µg of fentanyl and bupivacaine 0.125% at the rate of 3-5 ml/h in the epidural space. 3) IV morphine group (M): No medication was received epidurally. In case of visual analog scale (VAS) score more than four, one mg of IV morphine bolus was administered to patient. The blood pressure, heart rate, respiratory rate and pain severity were recorded at the moment of patient’s transfer from recovery room to the ward and compared in three groups every six hours for 24 hours. The results of this study were analyzed by statistical tests including repeated measures ANOVA, Kruskal-Wallis, Fisher’s exact test and SPSS software 16. P values less than 0.05 were considered statistically significant. Results: The results of the study showed that VAS score in fentanyl-bupivacaine group was significantly lower than that in the two other groups during the first 18 hours. However, VAS score in all groups decreased at 24th hour postoperatively (less than three) suggesting that there was no statistically significant difference between the three groups. In this study, no serious and severe complications were observed except for a few cases of nausea in the control group. Conclusion: Epidural analgesia with fentanyl-bupivacaine is a safe and effective way to postoperative pain management in listhesis and spinal surgeries.

Spinal Navigation in Minimally Invasive Spinal Fixation Surgery: A Retrospective Study of Our 4-Year Experience

Introduction Spinal navigation is considered a useful adjunct in minimally invasive spine surgery. Numerous reports suggesting lower radiation exposure have been described, but there have been concerns around increased operative times that navigation may attract. Materials and Methods Radiation exposure and surgical times were analyzed in all minimally invasive instrumented spine surgery cases performed between January 2010 and March 2014. A total of 141 cases were identified (degenerative, tumor, and trauma). These were divided into two groups: those performed with fluoroscopy guidance and those performed using intraoperative spinal navigation. These two groups were compared for cumulative radiation dose and operative times. Results Mann–Whitney nonparametric tests demonstrated a statistically significant lower radiation exposure in the navigated cases compared with the fluoroscopy cases (233.26 vs. 710.12 cGy/cm2; p &lt; 0.05) without any significant difference in operative times (195 vs. 206 minutes; p = 0.52). Conclusion Evolving technologies are increasing our ability to improve spinal fixation. Our experience indicates that spinal navigation, in particular in longer spinal stabilization procedures, can be a powerful tool to reduce radiation exposure to both the patient and operating room personnel.

Reliability of Postoperative Multislice Computed Tomography in Assessment of Pedicle Screw Placement in Thoracic and Lumbar Spinal Fixation

Objective This study aims to evaluate the reliability of three-dimensional (3D) volume rendering computed tomography (CT) in postoperative assessment of pedicle screw placement. Methods A total of 98 patients with previous spinal fixation surgery were included. All inserted screws were evaluated postoperatively within the first week using CT. Degree of misplacement and difference between CT images were recorded. Results Overall, 76, 68, and 39 misplaced screws were detected in 3D reformatted image, coronal reconstruction, and axial CT images, respectively. Dorsal spine had higher rate of violation 46 (9.95%) with the highest rate at T4 (12.8%) comparing it with lumber 32 (6.9%). Statistically significant differences were found between lateral and medial violation ( p = 0.03), between findings of CT 3D reformatted and axial image ( p = 0.04), and also in detecting end plate perforation and anterior vertebral encroachment in different CT images ( p = 0.013). Sensitivity for 3D reformatted image and axial image compared with surgical finding in six revised screws was 100 and 95.8% and specificity 100 and 88.7%, respectively. Highly momentous agreement reported with Kappa coefficient = 0.95 Â ± &lt; 0.001. Conclusion The vertebral body and the pedicle are 3D structures. Therefore, we have to study them as they are. The postoperative evaluation of pedicle screw using CT 3D reconstruction was a reliable method and unveiled the deficiencies in conventional axial CT.

Low Conductivity Material Detection Method Based on Eddy Current and GMR Sensors

The low conductivity material such as cancellous bone, cortical bone tissue and soft tissue is the mainly content in the spine. And the improvements on distinguishing the low conductivity material can make a contribution to the spinal fixation surgery process, and protect the patient from spine incident trauma injury during internal fixation prosthetics with implanting pedicle screws. As a result the low conductivity material detection is of great importance in biomedicine study. According to the magnetic property difference of different low conductivity material, an eddy current detection method based on GMR sensor which is proposed in this paper. Compared with coil sensor in traditional non-contact detecting system, GMR sensors have advantages of higher sensitivity, higher precision, better linearity and better stability. Based on this methods, this paper introduces a low conductivity material detection probe. Several experiments indicate that this detection method can detect the low conductivity material NaCl solution with conductivity of 0.128 S/m, whose electrical conductivity matches that of biological tissue. This results lay a solid foundation on the biological tissue detection research.