Spinal Hardware Research Articles

Consideration of Antifungal Coverage in Treating Infections Related to Delayed Esophageal Perforation from Anterior Cervical Spine Hardware

(1) Background/Objectives: Delayed esophageal perforation following anterior cervical (spine) discectomy and fusion (ACDF) is rare but can lead to serious infectious complications. The treatment usually involves hardware explanation and prolonged intravenous antibiotics; however, there are scarce reports about the microbiology of these infections and corresponding targeted therapy. (2) Methods: Patients diagnosed or treated for delayed esophageal perforation after anterior cervical fusion between 2000–2020 at a tertiary medical center were studied. (3) Results: Seven patients with delayed esophageal perforation following ACDF were identified. The most common bacteria isolated included Streptococcus, Haemophilus, and Mycobacterium species. The cultures from five patients grew fungal species, including Candida albicans and C. glabrata. All the patients received several weeks of broad-spectrum antibiotics, and, notably, 5/7 patients received antifungal therapy targeting Candida. (4) Conclusions: Although the incidence of delayed esophageal perforation following ACDF is low, providers should remain aware of this entity due to the serious infectious complications. Most infections are polymicrobial in nature, and providers should consider empiric antifungal coverage specifically targeting Candida species when treating patients with this complication.

Extensive Reactive Myelitis Secondary to Long-standing Cervical Spinal Hardware

Extensive Reactive Myelitis Secondary to Long-standing Cervical Spinal Hardware

Wearable bio-adhesive metal detector array (BioMDA) for spinal implants

Dynamic tracking of spinal instrumentation could facilitate real-time evaluation of hardware integrity and in so doing alert patients/clinicians of potential failure(s). Critically, no method yet exists to continually monitor the integrity of spinal hardware and by proxy the process of spinal arthrodesis; as such hardware failures are often not appreciated until clinical symptoms manifest. Accordingly, herein, we report on the development and engineering of a bio-adhesive metal detector array (BioMDA), a potential wearable solution for real-time, non-invasive positional analyses of osseous implants within the spine. The electromagnetic coupling mechanism and intimate interfacial adhesion enable the precise sensing of the metallic implants position without the use of radiation. The customized decoupling models developed facilitate the precise determination of the horizontal and vertical positions of the implants with incredible levels of accuracy (e.g., <0.5 mm). These data support the potential use of BioMDA in real-time/dynamic postoperative monitoring of spinal implants.

Complications of Hardware Removal in Pediatric Orthopaedic Surgery.

Hardware removal (HR) is one of the most common surgical procedures in pediatric orthopaedics. Surgeons advocate for HR for a variety of reasons, including to limit peri-implant fracture risk, restore native anatomy for adult reconstruction surgery, permit bone growth and development, and mitigate implant-related pain/irritation. To our knowledge, no recent study has investigated the characteristics and complications of HR in pediatric orthopaedics. The goal of this study is to report the prevalence and complications of hardware removals across all of pediatric orthopaedic surgery. A retrospective case series was conducted of all hardware removals from 2012 to 2023 performed at a single urban tertiary-care children's hospital. Cases were identified using CPT codes/billing records. Spinal hardware and cases for which hardware was either implanted or explanted at an outside hospital were excluded. Patient demographic and clinical data were recorded. For patients with multiple hardware removals, each case was recorded independently. A total of 2585 HR cases for 2176 children met study criteria (57.7% male; mean age 12.3±4.4y). The median postoperative follow-up time was 1.7 months (interquartile range: 0.6 to 6.9). The most common sites of hardware removal were the femur/knee (32.7%), tibia/fibula/ankle (19.3%), and pelvis/hip (18.5%). The most common complications included sustained, new-onset postoperative pain (2.6%), incomplete hardware removal (1.6%), and perioperative fracture (1.4%). The overall complication rate of hardware removal was 9.5%. Eighty-eight percent of patients who underwent hardware removal for pain experienced pain relief postoperatively. HR >18 months after insertion had a 1.2x higher odds of overall complication (P=0.002) and 3x higher odds of incomplete removal/breakage (P<0.001) than hardware removed 9 to 18 months after insertion. The overall complication rate of hardware removal across a large series in the pediatric population was 9.5%. Despite hardware removal being one of the most common and often routine procedures in pediatric orthopaedics, the complication rate is not benign. Surgeons should inform patients and families about the likelihood of success and the risks of incomplete removal during the informed consent process. IV.

Ruthenibacterium lactatiformans isolated from a human blood culture: a first report

BackgroundRuthenibacterium lactatiformans, a Gram-stain-negative, rod-shaped, obligate anaerobic bacterium of the Oscillospiraceae family, has not been previously reported in human infections. This study reports the first case of bacteraemia and potential vertebral osteomyelitis caused by Ruthenibacterium lactatiformans.Case presentationAn 82-year-old man with a history of diabetes, chronic renal failure, and prior spinal surgery for spondylolisthesis and spinal stenosis presented with fever and lower back pain. Magnetic resonance imaging revealed multiple vertebral osteomyelitis lesions. Initial blood cultures identified methicillin-resistant Staphylococcus aureus (MRSA), which prompted vancomycin treatment. However, repeated blood cultures not only confirmed persistent MRSA, but also detected Gram-negative bacilli (GNB). Despite surgical removal of the spinal hardware and antimicrobial therapy, the patient’s osteomyelitis worsened, necessitating transfer for further management. Subsequent analysis using 16S rRNA gene sequencing identified the GNB as Ruthenibacterium lactatiformans.ConclusionsThis is the first documented instance of human infection with Ruthenibacterium lactatiformans, signifying its pathogenic potential in vertebral osteomyelitis. The involvement of anaerobic bacteria and the possibility of polymicrobial infections complicate the diagnosis and treatment of vertebral osteomyelitis. This report underscores the need for caution when identifying the causative organism and selecting an appropriate treatment.

Single-level laminoplasty approach to selective dorsal rhizotomy with conus localization by rapid spine MRI

IntroductionWhile selective dorsal rhizotomy (SDR) was originally described as a multilevel approach, single-level approaches are now popularized. Conus localization is beneficial for operative planning in single-level selective dorsal rhizotomy. Our approach to SDR involves minimal exposure for a single-level laminoplasty, preserving one attached interspinous ligament. Pre-operative conus localization is required for this tailored approach to determine the laminoplasty level and dictate rostral or caudal division of the superior spinus ligament. While rapid MRI sequences have been popularized for pediatric cranial imaging, its utility for spinal imagining is less well-described, and specific application for conus localization has not been reported.ObjectiveIllustrate that rapid MRI without sedation is sufficient to identify conus level for tailored single-level laminoplasty SDR.Material and methodsPatients undergoing SDR from 2014 to 2022 at one institution were reviewed for type of pre-operative MRI (rapid vs full), conus level, procedural time for MRI, and radiology report. The typical rapid MRI has four sequences utilizing single-shot technique (scout, sagittal T2, axial T2, and axial T1) that typically take less than 1 min each of acquisition time, with non-single-shot sequences added periodically in cooperative patients. To include time for patient positioning, pre-scan shimming, procedural incidentals, and other patient-specific variations, MRI procedure length was recorded as documented in the electronic medical record.ResultsN = 100 patients had documentation of an MRI for pre-operative imaging. Seventy-nine of these had a rapid MRI, and 21 required a full MRI with anesthesia for their treatment plan. Mean total procedure time for rapid MRI was 21.5 min (median 17). Mean procedure time for MRI under general anesthesia was 91.2 min (median 94). Of patients with rapid MRI imaging, 2/79 had an ambiguous conus level (1 from motion artifact, 1 from spinal hardware) vs 1/21 with a full MRI under anesthesia (due to spinal hardware).ConclusionRapid spinal MRI without sedation can be used for conus localization in a pediatric population. This may be routinely used as pre-operative imaging for a single-level approach to selective dorsal rhizotomy, without sedation or intubation procedures.

A low-cost phantom design for evaluating spine SABR calculations in the presence of prosthetic vertebral stabilization.

Dose-perturbation characteristics are important to consider during the calculation of radiation therapy protocols for patients who are going to receive high doses that would reach the tolerance limits of the spinal cord [1]. Several studies have investigated dose perturbations introduced by metal implants in close proximity to spine SABR treatments [2-7]. However, there is a lack of work assessing this effect using the RayStation TPS [8]. We present an initial design for a low-cost phantom to evaluate spine stereotactic ablative radiotherapy (SABR) in the presence of prosthetic vertebral stabilization. The phantom is modular, allowing the prosthetic at the centre of the phantom to be removed by exchanging the central block. It also includes space to insert ion chamber and film. The agreement of the RayStation TPS (v8.0B) collapsed cone convolution (CCC) calculation and measurement was determined for phantom versions with and without prosthetic. There was little to no change in the agreement between the measured and calculated dose when introducing metallic hardware. This suggests that our Raystation-based SABR planning approach for patients with spinal hardware meets clinical expectations. Departments without access to anthropomorphic phantoms may find this design useful but should test their phantom design in typical clinical settings to ensure it is robust to real world situations.

Extruded Screw From Cervical Spine Hardware Causing Vocal Fold Paralysis.

Dysphonia and dysphagia are often observed among patients presenting to the otolaryngology clinic. One of the more common etiologies includes iatrogenic injury to the recurrent laryngeal nerve (RLN) as a known complication of head and neck surgeries such as thyroidectomy or anterior approaches to the cervical spine. Most often, RLN injury occurs in this context due to traction or transection of the nerve. No reports on delayed presentation of RLN injury from the extrusion of cervical spine hardware (screw) could be found in the peer-reviewed literature. We present a case of a 63-year-old woman who presented to the otolaryngology office with a 3-month history of hoarseness and difficulty swallowing. The patient's past medical history was significant for a motor vehicle accident (MVA) 6 years prior resulting in right arm radiculopathy and subsequent anterior cervical discectomy with spinal decompression and fusion (ACDF) at C5-C6 and C6-C7 approximately 3 months after the MVA. Strobovideolaryngoscopy revealed right vocal fold immobility. Computed tomography scan revealed that a screw from the right side of the ACDF hardware migrated approximately 2 cm with compression of the RLN. The patient underwent neck exploration with removal of the extruded hardware and microdirect laryngoscopy with right vocal fold injection laryngoplasty. Intraoperatively, the extruded screw was found embedded within the RLN fibers. This case represents the first report to our knowledge of extrusion of cervical spine hardware screw resulting in delayed RLN injury and vocal fold paralysis.

Low Tesla MR Imaging for Spine with Hardware

Acquiring MR images with minimized susceptibility artifacts is essential for spines with medical hardware to delineate clinical target volumes (CTVs) in radiation therapy for chordomas, chondrosarcomas, and other sarcomas. Since it can be more challenging to visualize the primary structures in high-tesla MR images due to metal-induced artifacts, we optimized imaging parameters to acquire high-quality, low-tesla MR images for clinical use. OptimalMR imaging parameters were investigated under general guidelines for artifact reduction techniques by testing several 3D spin echo and gradient echo sequences in a 0.23-T MR scanner. A customized spine phantom was developed to acquire MR images for bony materials which included, 4-6 industrial titanium screws, an aluminum plate, and a superflab bolus. While the 3D b-FFE sequence was used to acquire MR images with a high signal-to-noise ratio, the other 3D T1-FFE, THRIVE, and DTSE sequences were applied to reduce susceptible artifacts to the medical hardware. The optimized parameters determined in the phantom test were applied to the 15 clinical cases, including patients with residual spinal tumors and fusion hardware. The low-tesla MR imaging technique was also used to scan sarcomas of the extremities and re-irradiation cases of spinal metastases. The optimized low-tesla MR images in the spine were noticeably useful to guide CTV delineations for patients with medical hardware, especially for residual or recurrent tumors. The imaging technique to minimize susceptibility artifacts enabled a more defined separation of each hardware component from the spinal cord and CTVs. In spine metastasis cases, pre-irradiated target volumes were determined, reflecting property changes in the bone marrow. The MR images acquired using the optimized parameters showed minimal artifacts to scan spine patients with hardware. By using the low-tesla MR images, spinal chordoma and chondrosarcoma patients could be treated to improve tumor control probabilities with minimized complications.

Value of [18F]FDG PET/CT in Diagnosis and Management of Spondylodiscitis.

Vertebral osteomyelitis is the third most common form of osteomyelitis in patients over 50 years of age.Whereas prompt (pathogen-directed) therapy is crucially associated with better outcomes, the heterogeneous clinical presentation of disease with unspecific symptoms often delays adequate treatment initiation. Diagnosis requires a careful investigation of medical history, clinical findings and diagnostic imaging, including magnetic resonance imaging and nuclear medicine techniques.Due to its high sensitivity, [18F]FDG PET/CT is becoming increasingly important in diagnosis and management of spondylodiscitis, especially in the postoperative setting with presence of spinal hardware or other implantable devices in which MRI is limited.

Complications and Functional Outcomes After Esophageal Reconstruction with an Intact Larynx.

Esophageal defects can result from primary pathologies such as malignancy or stricture, or secondary ones such as perforation due to trauma or iatrogenic injury. Techniques, management, and outcomes of reconstruction in this setting are poorly understood. Herein, we aim to highlight surgical outcomes in patients undergoing local and free flap reconstruction of esophageal defects in the setting of an intact larynx. Retrospective review of patients who underwent esophageal reconstruction with an intact larynx between 2009 and 2022 at our institution was performed. Ten patients met inclusion criteria. Esophageal reconstruction was performed for extruded spinal hardware (n = 8), and esophageal stricture (n = 2). Four patients underwent reconstruction with free tissue transfer, and six with local pedicled flaps. There were no cases of flap failure, esophageal fistula, hematoma, or wound dehiscence. One patient had post-operative bleeding requiring return to the operating room. Three patients had a postoperative wound infection, two of whom required washout. There were no unplanned 30-day readmissions. At three months after operation, all patients who were not tube feed-dependent prior to surgery returned to oral intake. Of the four patients who were tube feed-dependent preoperatively, three were tolerating oral intake at nine months postoperatively. Nine patients (90%) had stable flexible laryngoscopy exams pre- and postoperatively with no voice changes. Reconstruction of esophageal defects in the setting of an intact larynx can be challenging. In this series, surgical intervention with free tissue transfer and local pedicled flaps was effective in returning patients to oral intake with low long-term morbidity. 4 Laryngoscope, 134:1227-1233, 2024.

Intravascular ultrasound to aid in the diagnosis and revision of an intra-aortic pedicle screw: illustrative case.

Pedicle screw impingement on vessel walls has the potential for complications due to pulsatile effects and wall erosion. Artifacts from spinal instrumentation create difficulty in accurately evaluating this interface. The authors present the first case of intravascular ultrasound (IVUS) used to characterize a pedicle screw breach into the aortic lumen. A 21-year-old female with surgically corrected scoliosis underwent computed tomography angiography (CTA) 3 years postoperatively, which revealed a pedicle screw within the thoracic aorta lumen. Metal artifact distorted the CTA images, which prompted the decision to use intraoperative IVUS. The IVUS confirmed the noninvasive imaging findings and guided final decisions regarding aortic endograft size and location during spine hardware revision. For asymptomatic patients presenting with pedicle screws malpositioned in or near the aorta, treatment decisions revolve around the extent of vessel wall penetration. Intraluminal depth can be obscured by artifact on computed tomography or magnetic resonance imaging or inadequately evaluated by a transesophageal echocardiogram. In our intraoperative experience, IVUS confirmed the depth of vessel lumen violation by a single pedicle screw and no wall penetration by two additional screws of concern. This was useful in deciding on thoracic endovascular aortic repair graft size and landing zone and facilitated safe spinal instrumentation removal and revision.

Novel Intrafraction Motion Tracking During Postoperative Spine Stereotactic Irradiation for a Patient With Carbon Fiber Fixation Hardware

Carbon-fiber reinforced (CFR) polyetheretherketone hardware is an alternative to traditional metal hardware used for spinal fixation surgeries before postoperative radiation therapy for patients with spinal metastases. CFR hardware's radiolucency decreases metal artifact, improving visualization and accuracy of treatment planning. We present the first clinical use and proof of principle of CFR spinal hardware with tantalum markers used for successful tracking of intrafraction motion (IM) using Varian TrueBeam IMR (Intrafraction Motion Review) software module during postoperative spine stereotactic radiation. A 63-year-old woman with history of endometrial cancer presented with acute back pain. Imaging demonstrated pathologic T12 vertebral fracture with cord compression. She underwent T12 vertebrectomy with circumferential decompression and posterior instrumented T10-L2 fusion at our facility using CFR-polyetheretherketone hardware with tantalum screw markers followed by postoperative stereotactic body radiation therapy to 3000 cGy in 5 fractions delivered to T11-T12. Tantalum screw markers were used for IMR tracking. During irradiation, 260 kV images were acquired, and IMR software was able to identify and track markers. During the entire treatment, the IM motions were less than 3 mm. This is the first presented case of CFR spinal hardware with tantalum markers used for successful IMR tracking of IM during daily spine stereotactic treatment. Future work will be needed to improve workflow and create a spine-specific IMR protocol.

ID: 214897 Peripheral Nerve Stimulation for Refractory Complex Regional Pain Syndrome Type I to Avoid Amputation

Peripheral nerve and dorsal root ganglion stimulation (DRG-s) are effective treatment modalities for focal complex regional pain syndrome (CRPS) that is limited to one or two dermatomes1,2,3. When deciding on a neural target for stimulation, consideration is given to the location of pain, MRI labeling, charge burden of external or internal pulse generator, spinal hardware, and medical comorbidities. While a reduction in pain of fifty percent or greater is often deemed a satisfactory response in the treatment of chronic pain, we describe a case were the patient sought amputation of her limb in the hopes a prosthetic extremity would provide improved function. Despite the risk of post amputation pain, there are patients that seek amputation for advanced CRPS that is refractory to treatment4,5,6. We proceeded with peripheral nerve stimulation (PNS) in addition to her DRG-s system in effort to avoid her upcoming amputation.

Value of [18F]FDG PET/CT in diagnosis and management of spondylodiscitis.

Vertebral osteomyelitis is the third most common form of osteomyelitis in patients over 50 years of age.Whereas prompt (pathogen-directed) therapy is crucially associated with better outcomes, the heterogeneous clinical presentation of disease with unspecific symptoms often delays adequate treatment initiation. Diagnosis requires a careful investigation of medical history, clinical findings and diagnostic imaging, including magnetic resonance imaging and nuclear medicine techniques.Due to its high sensitivity, [18F]FDG PET/CT is becoming increasingly important in diagnosis and management of spondylodiscitis, especially in the postoperative setting with presence of spinal hardware or other implantable devices in which MRI is limited.

Cutibacterium acnes in spine tissue: characteristics and outcomes of non-hardware-associated vertebral osteomyelitis.

Cutibacterium acnes isolation from spine tissue can be challenging because the organism can represent a contaminant. There is a paucity of data regarding the role of C.acnes in non-hardware-associated vertebral osteomyelitis (VO). Herein we evaluate the clinical and microbiological characteristics, treatment, and outcome of patients with C.acnes VO. Data were retrospectively collected from adults with a positive spine culture for C.acnes at Mayo Clinic, Rochester (MN), from 2011 to 2021. Patients with spinal hardware and polymicrobial infections were excluded. Of the subjects, 16 showed radiological and clinical findings of VO: 87.5 % were male, the average age was 58years ( SD), and back pain was the predominant symptom. Of the lesions, 89.5 % involved the thoracic spine. Of the subjects, 69 % had experienced an antecedent event at the site of VO. In five subjects, C.acnes was isolated after 7 d of anaerobic culture incubation. Thirteen subjects were treated with parenteral -lactams, and three with oral antimicrobials, without any evidence of recurrence. Twenty-one subjects were not treated for VO, as C.acnes was considered a contaminant; at follow-up, none had evidence of progressive disease. C.acnes should be part of microbiological differential diagnosis in patients with suspected VO, especially in the context of a prior spinal procedure. Anaerobic spine cultures should undergo prolonged incubation to enable recovery of C.acnes. C.acnes VO may be managed with oral or parenteral antimicrobial therapy. Without clinical and radiological evidence of VO, a single positive culture of C.acnes from spine tissue frequently represents contaminants.

676 Anatomic Assessment of L1-S1 Neural Foraminal Dimensions Using Computed Tomography

INTRODUCTION: While radiographic parameters for diagnosis of central lumbar canal stenosis are well known, parameters for diagnosis of neural foraminal stenosis are less well defined. Previous research has used magnetic resonance imaging (MRI) to describe neural foraminal dimensions. However, the blooming artifact on MRI may distort these measurements. There is limited research using computed tomography (CT) to investigate normal neuroforamina dimensions. METHODS: We evaluated CT imaging of 55 female and 55 male subjects between 18 and 35 years of age. Those with history of degenerative disc disease, spondylolisthesis, fracture, neoplasm, trauma, existing spinal hardware, CT imaging performed due to back pain, or previous spinal surgery were excluded from review. Three independent reviewers were trained by a board-certified neuroradiologist to measure L1-S1 neural foraminal dimensions bilaterally. Intraclass correlation coefficient (ICC) two-way mixed model on absolute agreement was used to analyze interrater reliability. Pearson’s correlation was used to evaluate associations among variables. Differences between sexes were analyzed using independent sample t-tests. Measurement differences between disc levels and left- and right-sided measurements were analyzed using paired sample t-tests and one-way analysis of variance. RESULTS: Mean subject age, height, weight, and BMI were 27.16 years, 1.71 m, 88.1 kg, and 29.63 kg/m2, respectively. No moderate or strong correlations were found between measurements and age, height, weight, or BMI for all levels L1-S1. No sex differences were found for measurements at all levels L1-S1. CONCLUSIONS: This study describes CT-based L1-S1 neural foraminal dimensions in patients without pathology affecting the neuroforamina. Dimensions were not strongly influenced by demographic or anthropometric factors.

A computer vision approach to identifying the manufacturer of posterior thoracolumbar instrumentation systems.

Knowledge of the manufacturer of the previously implanted pedicle screw systems prior to revision spinal surgery may facilitate faster and safer surgery. Often, this information is unavailable because patients are referred by other centers or because of missing information in the patients' records. Recently, machine learning and computer vision have gained wider use in clinical applications. The authors propose a computer vision approach to classify posterior thoracolumbar instrumentation systems. Lateral and anteroposterior (AP) radiographs obtained in patients undergoing posterior thoracolumbar pedicle screw implantation for any indication at the authors' institution (2015-2021) were obtained. DICOM images were cropped to include both the pedicle screws and rods. Images were labeled with the manufacturer according to the operative record. Multiple feature detection methods were tested (SURF, MESR, and Minimum Eigenvalues); however, the bag-of-visual-words technique with KAZE feature detection was ultimately used to construct a computer vision support vector machine (SVM) classifier for lateral, AP, and fused lateral and AP images. Accuracy was tested using an 80%/20% training/testing pseudorandom split over 100 iterations. Using a reader study, the authors compared the model performance with the current practice of surgeons and manufacturer representatives identifying spinal hardware by visual inspection. Among the three image types, 355 lateral, 379 AP, and 338 fused radiographs were obtained. The five pedicle screw implants included in this study were the Globus Medical Creo, Medtronic Solera, NuVasive Reline, Stryker Xia, and DePuy Expedium. When the two most common manufacturers used at the authors' institution were binarily classified (Globus Medical and Medtronic), the accuracy rates for lateral, AP, and fused images were 93.15% ± 4.06%, 88.98% ± 4.08%, and 91.08% ± 5.30%, respectively. Classification accuracy decreased by approximately 10% with each additional manufacturer added. The multilevel five-way classification accuracy rates for lateral, AP, and fused images were 64.27% ± 5.13%, 60.95% ± 5.52%, and 65.90% ± 5.14%, respectively. In the reader study, the model performed five-way classification on 100 test images with 79% accuracy in 14 seconds, compared with an average of 44% accuracy in 20 minutes for two surgeons and three manufacturer representatives. The authors developed a KAZE feature detector with an SVM classifier that successfully identified posterior thoracolumbar hardware at five-level classification. The model performed more accurately and efficiently than the method currently used in clinical practice. The relative computational simplicity of this model, from input to output, may facilitate future prospective studies in the clinical setting.

FactFinders for patient safety: Motor stimulation testing in lumbar radiofrequency neurotomy and radiofrequency neurotomy in patients with posterior hardware

This series of FactFinders presents a brief summary of the evidence and outlines recommendations regarding the use of motor stimulation testing in lumbar radiofrequency neurotomy and performance of radiofrequency neurotomy in patients with posterior spinal hardware.The evidence in support of the following facts is presented: (1) Motor stimulation does not inherently protect against unwanted damage to the spinal nerve, exiting spinal nerve root or its ventral ramus due to a lack of sensitivity of this test for identification of electrode contact or close proximity to sensorimotor nerves. Even when motor stimulation is performed, verification of correct electrode placement with multiplanar imaging including a minimum of true anterior-posterior and lateral fluoroscopic views is a recommended safeguard. (2) The existence of posterior spinal hardware is not an absolute contraindication to radiofrequency neurotomy, but direct contact with hardware should be avoided.

Implementation of triggered kilovoltage imaging for stereotactic radiotherapy of the spine for patients with spinal fixation hardware.

Mitigation of intrafraction motion (IM) is valuable in stereotactic radiotherapy (SRT) radiotherapy where submillimeter accuracy is desired. The purpose of this study was to investigate the application of triggered kilovoltage (kV) imaging for spine SRT patients with hardware by correlating kV imaging with patient motion and summarizing implications of tolerance for IM based on calculated dose. Ten plans (33 fractions) were studied, correlating kV imaging during treatment with pre- and post-treatment cone beam computed tomography (CBCT). Images were taken at 20-degree gantry angle intervals during the arc-based treatment. The contour of the hardware with a 1mm expansion was displayed at the treatment console to manually pause treatment delivery if the hardware was visually detected outside the contour. The treatment CBCTs were compared using retrospective image registration to assess the validity of contour-based method for pausing treatment. Finally, plans were generated to estimate dose volume objective differences in case of 1mm deviation. When kV imaging during treatment was used with the 1mm contour, 100% of the post-treatment CBCTs reported consistent results. One patient in the cohort exhibited motion greater than 1mm during treatment which allowed intervention and re-setup during treatment. The average translational motion was 0.35mm. Treatment plan comparison at 1mm deviation showed little differences in calculated dose for the target and cord. Utilizing kV imaging during treatment is an effective method of assessing IM for SRT spine patients with hardware without increasing treatment time.