Spinal Reconstruction Research Articles

Case Series: An Innovative Technique for Post-Corpectomy Reconstruction Using a Cage–Allograft/Autograft Construct

Study Design: This was a single-institution, retrospective cohort study. Objective: The objective of this study was to assess a surgical technique for spinal reconstruction after corpectomy, integrating an allograft/autograft within a vertebral body replacement cage linked to spinal rods via pedicle screws. This method aims to enhance biomechanical stability and promote long-term fusion without cage endcaps. Summary of Background data: Recent advancements in spinal surgery feature innovative constructs that improve healing and fusion rates. FDA-approved mesh cages provide enhanced stability and superior fusion with fewer complications. Our approach combines allografts/autografts with vertebral replacements, using a pedicle screw through the cage for significant biomechanical enhancement. Methods: Two patients undergoing cervical and lumbar spinal reconstructions due to different pathologies were selected. The surgical technique involved shaping the allograft/autograft to fit precisely within the cage, extending beyond its ends to facilitate fusion at both ends, and securing the construct to the spinal rods with pedicle screws for added stability. Patient outcomes were assessed based on post-operative stability, fusion rates, and the presence of any complications. Results: Both cases successfully utilized the technique, achieving stabilization and fusion. Improvements were noted in post-operative recovery. There were no instances of cage subsidence, or any significant complications directly related to the novel construct. Conclusions: Our case series highlights a post-corpectomy reconstruction technique involving a mesh cage construct integrated with an autograft/allograft and connected to posterior instrumentation for enhanced stability. This technique was applied successfully in two cases, demonstrating its feasibility, durability, and potential to promote biological integration. Further studies with larger cohorts and extended follow-up periods are necessary to refine the approach for wider clinical use.

Psychological distress does not predict decisional regret in patients undergoing spinal reconstruction for adult spinal deformity

PurposeThe study aimed to assess the link between preoperative psychological distress and postoperative decisional regret in adult spinal deformity (ASD) surgery patients. We hypothesized that greater pre-surgery distress would correlate with higher post-surgery regret. This evaluation was based on a retrospective case series from an institution with standardized surgical guidelines for ASD.MethodsThis IRB-approved retrospective study analyzed our institution’s ASD database from 2014 to 2020. Eligible patients had a minimum two-year post-op follow-up and preoperative psychological distress assessment. Patients were grouped based on psychological distress levels: green, yellow, and yellow minus. Regret post-surgery was assessed using the Decision Regret Scale and SRS-22 Question 22. Logistic regression evaluated the impact of distress levels on regret, controlling for age and sex.ResultsOut of 167 eligible patients, 112 responded and were analyzed. No significant demographic differences were observed between responders and non-responders. Using the Decision Regret Scale, 41% expressed no regret, while 63% expressed no regret with the SRS-22 questionnaire’s Single-Item scale. Only the yellow minus group showed significant regret difference based on osteotomy, with non-recipients more likely to express regret.ConclusionThis study found no significant link between psychological distress and post-operative regret in adult spinal deformity surgery after a minimum 2-year follow-up. Although nearly 60% exhibited some post-surgery regret, predicting regret based on psychological burden or demographics remains challenging. Further research is essential to identify factors contributing to post-operative regret in spinal deformity surgery patients.

Generate and Analyze Three-Dimensional Dendritic Spine Morphology Datasets With SpineTool Software.

Dendritic spine morphology is associated with the current state of the synapse and neuron, and changes during synaptic plasticity in response to stimulus. At the same time, dendritic spine alterations are reported during various neurodegenerative and neurodevelopmental disorders and other brain states. Accurate and informative analysis of spine shape has an urgent need for studying the synaptic processes and molecular pathways in normal and pathological conditions, and for testing synapto-protective strategies during preclinical studies. Primary neuronal cultures enable high quality imaging of dendritic spines and offer a wide spectrum of accessible experimental manipulations. This article outlines the protocol for isolating, culturing, fluorescent labeling, and imaging of mouse primary hippocampal neurons by three-dimensional (3D) confocal microscopy in a normal state and in conditions of low amyloid toxicity-an in vitro model of Alzheimer's disease. An alternate protocol describes the neuronal morphology analysis using the EGFP expressing neurons in line-M transgenic mouse brain slices. Since the dendritic spines are relatively small structures lying close to the confocal microscope resolution limit, their proper segmentation on the images is challenging. This protocol highlights the image-preprocessing steps, including generation of theoretical point spread function and deconvolution, which enhances resolution and removes noise, thereby enhancing the 3D spine reconstruction results. SpineTool, an open source Python-based script, enables 3D segmentation of dendrites and spines and numerical metric calculation, including key measures, such as spine length, volume, and surface area, with a new feature, the chord length distribution histogram, improving clustering results. SpineTool supports both manual and machine learning spine classification (i.e., mushroom, thin, stubby, filopodia) and automated clustering using k-means and DBSCAN methods. This protocol provides detailed instructions for using SpineTool to analyze and classify dendritic spines in control and experimental groups, enhancing our understanding of spine morphology across different experimental conditions. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Obtaining 3D confocal dendritic spine images of hippocampal neuronal culture in normal state and conditions of low amyloid toxicity Alternate Protocol: Obtaining confocal dendritic spine images of mice hippocampal neurons from fixed brain slices Support Protocol: Post-processing deconvolution of confocal images Basic Protocol 2: Segmentation of dendritic spines with SpineTool Basic Protocol 3: Spine dataset preparation using SpineTool Basic Protocol 4: Clustering of dendritic spines with SpineTool Basic Protocol 5: Machine classification of dendritic spines with SpineTool.

Early clinical efficacy of 3D-printed artificial vertebral body in spinal reconstruction after total en bloc spondylectomy for spinal tumors

BackgroundTotal en bloc spondylectomy (TES) is a recognized surgical approach for managing spinal tumors. With advancements in three-dimensional (3D) printing technology, the use of 3D-printed prosthetics for vertebral reconstruction post-tumor resection has gained traction. However, research on the clinical implications of these prosthetics remains limited.MethodsThis retrospective study evaluated patients who underwent TES for primary and metastatic thoracolumbar tumors at the Department of Spinal Surgery, Tianjin Hospital, between October 2017 and September 2020. These patients received anterior reconstruction with 3D-printed artificial vertebral bodies.Results14 patients completed the surgery, with intraoperative blood loss ranging from 1,400 to 4,200 ml (mean 2,767 ± 790 ml) and operative duration between 240 and 520 min (mean 382 ± 75.9 min). The follow-up period extended from 7 to 43 months, with an average of 19.9 ± 9.5 months. Standardized prefabricated prosthetics were utilized in nine patients, while five received customized prosthetics. Throughout the follow-up, there were no reports of posterior connecting rod, 3D-printed prosthetic, or pedicle screw failures. Notably, one patient presented with significant prosthetic subsidence resulting in screw loosening, and three cases of prosthetic subsidence were observed.ConclusionThe incorporation of 3D-printed prosthetics in TES procedures yielded favorable clinical outcomes. Further research is warranted to optimize these prosthetics for enhanced postoperative stability and patient-specific applications.

MRI Spinal Cord Reconstruction Provides Insights into Mapping and Migration Following Percutaneous Epidural Stimulation Implantation in Spinal Cord Injury.

Background: Spinal cord epidural stimulation (SCES) has the potential to restore motor functions following spinal cord injury (SCI). Spinal cord mapping is a cornerstone step towards successfully configuring SCES to improve motor function, aiming to restore standing and stepping abilities in individuals with SCI. While some centers have advocated for the use of intraoperative mapping to anatomically target the spinal cord locomotor centers, this is a resource-intensive endeavor and may not be a feasible approach in all centers. Methods: Two participants underwent percutaneous SCES implantation as part of a clinical trial. Each participant underwent a temporary (1-week, two-lead) trial followed by a permanent, two-lead implantation. SCES configurations were matched between temporary and permanent mappings, and motor evoked potential in response to 2 Hz, for a duration of 250-1000 µs and with an amplitude of 1-14 mA, was measured using electromyography. T2 axial MRI images captured prior to implantation were used to retrospectively reconstruct the lumbosacral segments of the spinal cord. The effects of lead migration on mapping were further determined in one of the participants. Results: In both participants, there were recognized discrepancies in the recruitment curves of the motor evoked potentials across different muscle groups between temporary and permanent SCES mappings. These may be explained by retrospective MRI reconstruction of the spinal cord, which indicated that the percutaneous leads did not specifically target the entire L1-S2 segments in both participants. Minor lead migration appeared to have a minimal impact on spinal cord mapping outcomes in one of the participants but did dampen the motor activity of the hip and knee muscle groups. Conclusions: Temporary mapping coupled with MRI reconstruction has the potential to be considered as guidance for permanent implantation considering target activation of the spinal cord locomotor centers. Since lead migration may alter the synergistic coordination between different muscle groups and since lead migration of 1-2 contacts is expected and planned for in clinical practice, it can be better guided with proper spinal cord mapping and a diligent SCES lead trial beforehand.

Entry point and screw path study of second sacral alar-iliac screw trajectory in spinal pelvic fixation under O-arm navigation

Objective: To explore the feasibility of using the entry point and screw path parameters of sacroiliac (S2AI) screws inserted under O-arm 3D computer navigation as a reference for freehand screw insertion in patients with degenerative spinal deformities. Methods: A retrospective analysis was conducted on the clinical data of 66 patients with degenerative spinal deformities who received S2AI screw fixation assisted by the O-arm 3D computer navigation system at Nanjing Drum Tower Hospital Affiliated with Nanjing University Medical School from January 2017 to April 2022. The patients included 6 males and 60 females, with a mean age of (64.3±5.9) years. Preoperatively, the entry point was set as the intersection of 1 mm from the outer and lower edges of the S1 foramen, adjusted intraoperatively by navigation, and verified postoperatively by full spinal CT scans and 3D reconstructions. Using the S1 screw entry point as the origin, the position of the bilateral S2AI screw entry points, tailward angulation (SA), outward angulation (TA), and vertical distance from the entry point to the skin (SD) were measured on postoperative CT 3D images. The accuracy of S2AI screw placement and any intraoperative and postoperative complications were recorded. Differences in entry point coordinates and screw path parameters between the left and right sides were compared. The intraclass correlation coefficient (ICC) was used to assess intra-observer and inter-observer agreement. Results: The coordinates and screw path parameters for the S2AI screws placed using the O-arm navigation demonstrated good intra-observer and inter-observer consistency (ICC>0.75). The left entry point was located (8.08±1.39) mm laterally and (24.47±2.20) mm caudally from the S1 entry point, while the right entry point was (8.09±1.41) mm laterally and (24.40±2.54) mm caudally, with no significant difference between the left and right sides (both P>0.05). The left TA was 46.33°±3.44°, SA was 39.14°±6.12°, and SD was (60.38±13.37) mm; the right TA was 46.37°±3.41°, SA was 39.59°±5.89°, and SD was (60.30±12.24) mm, with no significant differences between the left and right parameters (all P>0.05). There was no significant neurovascular complications intraoperatively or two weeks postoperatively, with a screw insertion accuracy of 97.7% (129/132). Conclusions: In the fixation of the pelvis in degenerative spinal deformities, the use of O-arm navigation-assisted S2AI screw insertion has a high accuracy rate. It is recommended that for freehand screw insertion, the entry point should be located 24 mm caudally and 8 mm laterally from the outer and lower edges of the superior articular process of S1, with an TA of approximately 46° and a SA of approximately 39°.

3D external shape analysis and barycentremetry can provide early signs of progression in adolescent idiopathic scoliosis.

Our objective was to analysis the barycentremetry, obtained from the external envelope reconstruction of biplanar radiographs, in adolescent idiopathic scoliosis (AIS) and to determine whether assessing would help predict the distinction between progressive and stable AIS at the early stage. A retrospective study with a multicentre cohort of 205 AIS was conducted. All AIS underwent a biplanar X-ray between 2013 and 2020. Inclusion criteria were Cobb angle between 10° and 25°; Risser sign lower than 3; age higher than 10years; and no previous treatment. A 3D spine reconstruction was performed, and the barycentremetry parameters were computed, i.e., the center of mass position at the apex and the axial torque at the apex, the upper and lower junction. A severity index, helping to distinguish stable and progressive AIS, was computed on the first radiograph, and weighted according to these parameters. A clinical and radiographic monitoring determined if AIS were classified such a stable or progressive scoliosis. One hundred and sixty-two AIS were included (i.e., 87 were classified as stable and 75 as progressive). The apex center of mass position was different between the stable and progressive AIS groups (6mm, SD = 4mm for the whole cohort; 5mm, SD = 4mm for stable AIS versus 7mm, SD = 4mm for progressive AIS; p = 0.02). In AIS thoracic, the specificity and positive predictive value of the severity index increased by 19% and 16%, respectively, by adding the apex vertebral axial torque. Early assessment of the external envelope from biplanar X-ray reconstruction of idiopathic scoliosis showed that the apex centre of mass position was significantly different between progressive and stable scoliosis. The inclusion of the axial torque of the apex vertebra in the severity index is promising to help the clinician distinguish between stable and progressive thoracic AIS at an early stage. II - Prognostic studies.

A Systematic Review of the Complications Associated with Free Fibular Flaps in Adult and Pediatric Spinal Reconstruction.

Free fibular flaps have been suggested as a modality of reconstruction for complex spinal deformities. However, there is limited data that describes associated postoperative outcomes. The purpose of this systematic review was to characterize outcomes after spinal reconstruction using the free fibular flap for both adults and children. Thirty-nine articles among four databases were identified as having met inclusion criteria. Patient demographics, indications for spinal reconstruction as well as location and anastomosis, history of chemotherapy and radiation therapy, and postoperative outcomes including complications were identified. Major complications were defined as complications requiring reoperation, while minor complications were those that did not require reoperation. Systemic complications were defined as complications affecting sites or organ systems beyond the local donor and recipient sites. Statistical analysis was performed using Fischer's exact, chi-squared, and t-tests. We identified 218 adult patients (mean age 47.7 years, 56.4% male) and 27 pediatric patients (mean age 12.7 years, 55.6% male). While there was no significant difference in the rates of bony union between the two groups (adults: 90.8%, children: 90%, p > 0.9), adults had significantly higher rates of major (27% vs. 7.4%, p = 0.026), minor (26.1% vs. 7.4%, p = 0.032), and systemic (14.2% vs. 0%, p = 0.047) complications. Free fibular flaps are effective for spinal reconstruction for both adults and children, as evidenced by the high rates of bony union. However, adults exhibited significantly higher complication rates. Further research is required to better understand the patient and clinical risk factors associated with increased rate of complications.

Posterior Correction and Fusion Using a 4D Anatomical Spinal Reconstruction Technique Improves Postural Stability Under the Eye-Closed Condition in Patients with Adolescent Idiopathic Scoliosis.

Background: Patients with adolescent idiopathic scoliosis (AIS) has been reported to exhibit impaired postural stability. Posterior correction and fusion using four-dimensional (4D) anatomical spinal reconstruction techniques may improve postural stability to correct the spine for optimal anatomical alignment. This prospective study aimed to determine the effect of posterior correction and fusion using a 4D anatomical spinal reconstruction technique on postural stability in the eye-open and eye-closed standing position in patients with thoracic AIS. Methods: Thirty-three patients with AIS, excluding those with Lenke type 5C AIS, participated in the study. The mean and standard deviation of the minimum values of the time-to-boundary (TTB) were determined. All patients were asked to perform the quiet standing position under the eye-open and eye-closed condition on a force plate preoperatively and at 1 week and 2 years postoperatively. The TTB value was calculated from the velocity and distance to the foot boundary of the acquired center-of-pressure data. Results: Under the eye-closed condition, the mean and standard deviation of the minimum TTB were significantly higher at 2 years postoperatively than preoperatively and at 1 week postoperatively. The mean and standard deviation of the minimum TTB values were significantly lower at 1 week postoperatively than preoperatively. Conclusions: The results of this study suggest that surgery using the 4D anatomical spinal reconstruction technique reduces postural stability immediately after surgery; however, it improves postural stability at 2 years compared to the preoperative values.

Patient-specific 3D-Printed PEEK implants for spinal tumor surgery

Aims & objectivesThis study evaluates the feasibility and clinical outcomes of using 3D-printed polyetheretherketone (PEEK) patient-specific implants (PSI) for vertebral body replacement (VBR) in patients with spinal tumors. The research question focuses on postoperative results, implant integration, and complications over a 12-month period. MethodsA single-center, retrospective case series analyzed five patients who underwent spinal reconstruction after tumor resection using PEEK 3D VBR between April 2022 and June 2023. Inclusion criteria were thoracic/lumbar spinal tumors, tumor resection with PEEK 3D VBR reconstruction, and follow-up exceeding 12 months. PEEK implants were created using fused filament fabrication from medical-grade PEEK. Patient data included demographics, medical history, tumor characteristics, and surgical outcomes. Radiological evaluations assessed bony fusion, local angle changes, and segment height stability. Descriptive statistical analyses were performed using R software. ResultsThe mean follow-up duration was 19.2 months. All patients remained alive, with one experiencing local recurrence. Postoperative imaging showed a decrease in local angle with no significant changes during follow-up. Segment heights remained stable, and no PEEK 3D VBR subsidence or hardware failure was observed. Bony fusion was observed in all patients. ConclusionsThe use of PEEK 3D printed PSI for VBR in spinal tumor patients demonstrates promising feasibility and clinical outcomes, with stable implant integration and minimal complications over a 12-month period. Further studies with larger cohorts are recommended to validate these findings.

Computer-Aided Design and Manufacturing to Facilitate Microvascular Free Tissue Transfer in Extremity, Pelvic, and Spinal Reconstructions.

Numerous surgical fields have embraced computer-aided design and computer-aided manufacturing (CAD/CAM), including plastic and reconstructive surgery. However, most of the literature and clinical use pertains to reconstruction of the head and neck. Herein, we provide a case series and systematic review of the literature, documenting the use of CAD/CAM in facilitating complex microvascular free tissue transfer for reconstructions involving the extremities, pelvis, and spine (EPS). This study consisted of two components: a case series and a systematic review of the literature. For the case series, the senior author's cases that included CAD/CAM to assist microvascular free tissue transfer reconstructions of the EPS were included. For the systematic review, all PubMed-, Scopus-, and Google Scholar-indexed studies describing the use of CAD/CAM to facilitate free tissue transfer in the EPS were identified and included using PRSMA guidelines. The case series identified 10 patients who received CAD/CAM-assisted microvascular reconstruction. Our systematic review identified 15 articles, representing 124 patients and 133 CAD/CAM-assisted free tissue transfers. Most authors believed that CAD/CAM facilitated a more efficient operation by shifting much of the intraoperative planning to the preoperative phase, ultimately translating to a shorter and more accurate surgery with improved function and cosmesis. CAD/CAM can be used to facilitate microvascular reconstruction of the EPS. Our cases series and systematic review suggest that CAD/CAM for EPS surgery may improve outcomes.

Risk factors and clinical significance of posterior slip of the proximal vertebral body after lower lumbar fusion.

Adjacent segment disease (ASD) after fusion surgery is frequently manifests as a cranial segment instability, disc herniation, spinal canal stenosis, spondylolisthesis or retrolisthesis. The risk factors and mechanisms of ASD have been widely discussed but never clearly defined. To investigate the risk factors and clinical significance of retrograde movement of the proximal vertebral body after lower lumbar fusion. This was a retrospective analysis of the clinical data of patients who underwent transforaminal lumbar interbody fusion surgery between September 2015 and July 2021 and who were followed up for more than 2 years. Ninety-one patients with degenerative lumbar diseases were included (22 males and 69 females), with an average age of 52.3 years (40-73 years). According to whether there was retrograde movement of the adjacent vertebral body on postoperative X-rays, the patients were divided into retrograde and nonretrograde groups. The sagittal parameters of the spine and pelvis were evaluated before surgery, after surgery, and at the final follow-up. At the same time, the Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) were used to evaluate the patients' quality of life. Nineteen patients (20.9%) who experienced retrograde movement of proximal adjacent segments were included in this study. The pelvic incidence (PI) of the patients in the retrograde group were significantly higher than those of the patients in the nonretrograde group before surgery, after surgery and at the final follow-up (P < 0.05). There was no significant difference in lumbar lordosis (LL) between the two groups before the operation, but LL in the retrograde group was significantly greater than that in the nonretrograde group postoperatively and at the final follow-up. No significant differences were detected in terms of the |PI-LL|, and there was no significant difference in the preoperative lordosis distribution index (LDI) between the two groups. The LDIs of the retrograde group were 68.1% ± 11.5% and 67.2% ± 11.9%, respectively, which were significantly lower than those of the nonretrograde group (75.7% ± 10.4% and 74.3% ± 9.4%, respectively) (P < 0.05). Moreover, the patients in the retrograde group had a greater incidence of a LDI < 50% than those in the nonretrograde group (P < 0.05). There were no significant differences in the ODI or VAS scores between the two groups before the operation, but the ODI and VAS scores in the retrograde group were significantly worse than those in the nonretrograde group after the operation and at the last follow-up, (P < 0.05). The incidence of posterior slippage after lower lumbar fusion was approximately 20.9%. The risk factors are related to a higher PI and distribution of lumbar lordosis. When a patient has a high PI and insufficient reconstruction of the lower lumbar spine, adjacent segment compensation via posterior vertebral body slippage is one of the factors that significantly affects surgical outcomes.

Does Pedicle Morphology Affect the Safety and Accuracy of Pedicle Screw Placement Using 3D-Printed Guides? A 5-Year, Single-Center Experience With 2210 Screws Placed for Adult Spinal Deformity Reconstruction.

Adult spinal deformity (ASD) surgery often involves the placement of pedicle screws using various methods, including freehand technique, fluoroscopic guidance, and computer-assisted intraoperative navigation, each with distinct limitations. Particularly challenging is the instrumentation of pedicles with small or absent cancellous channels (Watanabe types C and D pedicles), commonly found at the apex of large curves where precise screw placement is crucial for effective deformity correction. 3D-printed pedicle screw drill guides (3DPSG) may assist in accurately placing pedicle screws while minimally disrupting the standard ASD surgery workflow. This study aims to evaluate the safety and efficacy of 3DPSG in ASD patients with Watanabe types C and D pedicles, where the safe corridor for screw placement is limited. 3DPSG were designed using fine cut (≤1.25 mm) computed tomography scans. Preoperative screw trajectory planning and guide manufacturing were conducted using computer-aided design software (Mighty Oak Medical, Englewood, CO). Four ASD surgeons with varying experience levels placed the guides. Data on patient demographics, pedicle morphology, number of levels instrumented, and implant-related complications were collected. The study included 115 patients (median age 67, range 18-81 years) with 2210 screws placed from T1 to L5. The median number of levels instrumented per case was 11 (range 7-12). Diagnoses included adult degenerative scoliosis (n = 62), adult idiopathic scoliosis (n = 30), Scheuermann's kyphosis (n = 2), and other complex conditions (n = 21). The overall accuracy rate for pedicle screw placement was 99.5%, with a 0% malposition rate in type C and D pedicles. No vascular or neurological complications or reoperations related to screw placement were reported. 3DPSG facilitates safe and accurate pedicle screw placement regardless of pedicle morphology in ASD surgeries. This includes the challenging Watanabe types C and D pedicles, typically found at curve apices, enabling surgeons to achieve high implant density and optimal spinal fixation in ASD patients.

Vascularized bone grafts in spinal reconstruction: An updated comprehensive review

In the past two decades, plastic surgeons have advanced to the forefront of spinal surgery, joining orthopedic and neurosurgeons in the multidisciplinary field of spino-plastics. As the global disease burden grows with an increased incidence of spinal pathologies, vascularized bone grafts (VBGs) define the current frontier of spino-plastic surgery. Vascularized bone grafting involves lifting segments of bone with the muscular attachments but without the inclusion of a named vessel. When compared to traditional nonvascular bone grafts and allografts, VBGs have come forward as a favored technique for complex spinal reconstruction due to the unique opportunity to capitalize on the relationship between the tendons and Sharpey's fibers which maintain blood flow to both the bone and muscular segments. This technique ensures robust autologous tissue rearrangement and also takes advantage of the osteoinductive properties of the bone segments, promoting adequate structural support and the perfusion necessary for efficient direct healing and fusion in intricate spine reconstructions. Another one of the many favorable qualities of VBGs is the diversity of sources available to surgeons. The review explores the role of VBGs in enhancing spinal fusion rates and minimizing morbidity compared to traditional approaches. Additionally, a detailed examination of six common VBG sources-the iliac crest, ribs, medial scapula, occiput, spinous processes, and clavicle is included, highlighting each graft's specific techniques and emphasizing the range of options available to spino-plastic surgeons.

Domain adaptation strategies for 3D reconstruction of the lumbar spine using real fluoroscopy data

In this study, we address critical barriers hindering the widespread adoption of surgical navigation in orthopedic surgeries due to limitations such as time constraints, cost implications, radiation concerns, and integration within the surgical workflow. Recently, our work X23D showed an approach for generating 3D anatomical models of the spine from only a few intraoperative fluoroscopic images. This approach negates the need for conventional registration-based surgical navigation by creating a direct intraoperative 3D reconstruction of the anatomy. Despite these strides, the practical application of X23D has been limited by a significant domain gap between synthetic training data and real intraoperative images.In response, we devised a novel data collection protocol to assemble a paired dataset consisting of synthetic and real fluoroscopic images captured from identical perspectives. Leveraging this unique dataset, we refined our deep learning model through transfer learning, effectively bridging the domain gap between synthetic and real X-ray data. We introduce an innovative approach combining style transfer with the curated paired dataset. This method transforms real X-ray images into the synthetic domain, enabling the in-silico-trained X23D model to achieve high accuracy in real-world settings.Our results demonstrated that the refined model can rapidly generate accurate 3D reconstructions of the entire lumbar spine from as few as three intraoperative fluoroscopic shots. The enhanced model reached a sufficient accuracy, achieving an 84% F1 score, equating to the benchmark set solely by synthetic data in previous research. Moreover, with an impressive computational time of just 81.1 ms, our approach offers real-time capabilities, vital for successful integration into active surgical procedures.By investigating optimal imaging setups and view angle dependencies, we have further validated the practicality and reliability of our system in a clinical environment. Our research represents a promising advancement in intraoperative 3D reconstruction. This innovation has the potential to enhance intraoperative surgical planning, navigation, and surgical robotics.

Multiplanar reconstructions of the thoracic spine in a photon counting dual-source CT scanner: comparison to EID-CT.

Photon-counting detector computed tomography (PCD-CT) is a groundbreaking technology with promising results for visualization of small bone structures. To analyze the delineation of the thoracic spine in multiplanar reconstructions (MPR) on PCD-CT compared to energy-integrating detector (EID)-CT. Two euthanized mice were examined using different scanners: (i) 20-slice EID-CT and (ii) dual-source PCD-CT at various CTDIVol values. Readers evaluated the thoracic spine and selected series with best visualization among signal-to-noise ratio (SNR)-matched pairs. SNR was significantly higher in PCD-CT reconstructions (Br68) and lower in Hr98 reconstructions compared to EID-CT. Bone detail visualization was superior in PCD-CT (especially in Hr98 reconstructions) compared to EID-CT. MPR on a PCD-CT had a higher SNR and better bone detail visualization even at lower radiation doses compared to EID-CT. PCD-CT with bone reconstructions showed the best delineation of small bone structures and might be considered in clinical routine.

Hounsfield units in assessing bone mineral density in ankylosing spondylitis patients with cervical fracture-dislocation.

Cervical spine fracture-dislocations in patients with ankylosing spondylitis (AS) are mostly unstable and require surgery. However, osteoporosis, one of the comorbidities for AS, could lead to detrimental prognoses. There are few accurate assessments of bone mineral density in AS patients. To analyze Hounsfield units (HUs) for assessing bone mineral density in AS patients with cervical fracture-dislocation. The HUs from C2 to C7 of 51 patients obtained from computed tomography (CT) scans and three-dimensional reconstruction of the cervical spine were independently assessed by two trained spinal surgeons and statistically analyzed. Inter-reader reliability and agreement were assessed by interclass correlation coefficient. The HUs decreased gradually from C2 to C7. The mean values of the left and right levels were significantly higher than those in the middle. Among the 51 patients, 25 patients (49.02%) may be diagnosed with osteoporosis, and 16 patients (31.37%) may be diagnosed with osteopenia. The HUs obtained by cervical spine CT are feasible for assessing bone mineral density with excellent agreement in AS patients with cervical fracture-dislocation.

Automatic 3D reconstruction of vertebrae from orthogonal bi-planar radiographs

When conducting spine-related diagnosis and surgery, the three-dimensional (3D) upright posture of the spine under natural weight bearing is of significant clinical value for physicians to analyze the force on the spine. However, existing medical imaging technologies cannot meet current requirements of medical service. On the one hand, the mainstream 3D volumetric imaging modalities (e.g. CT and MRI) require patients to lie down during the imaging process. On the other hand, the imaging modalities conducted in an upright posture (e.g. radiograph) can only realize 2D projections, which lose the valid information of spinal anatomy and curvature. Developments of deep learning-based 3D reconstruction methods bring potential to overcome the limitations of the existing medical imaging technologies. To deal with the limitations of current medical imaging technologies as is described above, in this paper, we propose a novel deep learning framework, ReVerteR, which can realize automatic 3D Reconstruction of Vertebrae from orthogonal bi-planar Radiographs. With the utilization of self-attention mechanism and specially designed loss function combining Dice, Hausdorff, Focal, and MSE, ReVerteR can alleviate the sample-imbalance problem during the reconstruction process and realize the fusion of the centroid annotation and the focused vertebra. Furthermore, aiming at automatic and customized 3D spinal reconstruction in real-world scenarios, we extend ReVerteR to a clinical deployment-oriented framework, and develop an interactive interface with all functions in the framework integrated so as to enhance human–computer interaction during clinical decision-making. Extensive experiments and visualization conducted on our constructed datasets based on two benchmark datasets of spinal CT, VerSe 2019 and VerSe 2020, demonstrate the effectiveness of our proposed ReVerteR. In this paper, we propose an automatic 3D reconstruction method of vertebrae based on orthogonal bi-planar radiographs. With the 3D upright posture of the spine under natural weight bearing effectively constructed, our proposed method is expected to better support doctors make clinical decision during spine-related diagnosis and surgery.

Fibula Free Flap Reconstruction of Cervical Spine Defects: A Multi-Institutional Study.

Cervical spine defects result in spinal instability, putting the spinal cord and vertebral arteries at risk of damage and possibly devastating neurological injuries. The fibula free flap can span the spinal defects for stability. There is a paucity of literature on this technique. Multi-institutional retrospective case series reviewing patients who underwent cervical spine reconstruction with a fibula free flap. Patient demographic information, comorbidities, characteristics of cervical spine defects, and free flap complications were collected. A total of 1187 fibula free flaps across 10 different institutions were reviewed. Thirteen patients (1.09%) underwent cervical spine reconstruction with a fibula free flap. Average age was 52.3 years old with an age range of 12-79 years. There were six males (46.1%) and seven females (53.8%). The most common defect etiology was infection (n = 6, 46.1%). Most commonly involved cervical spine level of the defect was C5 (n = 10) followed by C6 (n = 9) and C4 (n = 8). The majority of reconstructed defects spanned three or more cervical levels, (n = 9, 69.2%). Facial artery was the most common arterial anastomosis (n = 8). Eight patients (61.5%) required a tracheostomy during their postoperative course. None of the patients had symptomatic or radiographic nonunion. This case series demonstrates that a vascularized fibula flap is a potential reconstructive option for cervical spine defects, especially in defects greater than three cervical levels, in the setting of infection, and previously radiated patients. 4 Laryngoscope, 134:4923-4928, 2024.

Use of Patient-Specific Interbody Cages Through a Minimally Invasive Lateral Approach for Unstable Lumbar Spondylodiskitis.

Patients with diskitis/osteomyelitis who do not respond to medical treatment or develop spinal instability/deformity may warrant surgical intervention. Irregular bony destruction due to the infection can pose a challenge for spinal reconstruction. The authors report a lateral approach using patient-specific interbody cages combined with posterior or lateral instrumentation to achieve spinal reconstruction for spinal instability/deformity from spondylodiskitis. This is a retrospective review of 4 cases undergoing debridement, lateral lumbar interbody fusion using patient-specific interbody cages, and supplemental lateral or posterior instrumentation for spinal instability/deformity after spondylodiskitis. The surgical technique is reported, as are the clinical and imaging outcomes. Four male patients with a mean age of 69 years comprised this study. One had lateral lumbar interbody fusion at L2/3 and 3 at L4/5. The mean hospital stay was 5.8 days. The mean follow-up was 8.5 months (range 6-12 months). There were no approach-related neurological injuries or complications. The mean visual analog scale back pain scores improved from 9.5 to 1.5, and the mean Oswestry disability index improved from 68.5 to 23 at the end of the follow-up. The mean lumbar lordosis increased from 18° to 51°. The segmental angle increased from 6.5° to 18°. The coronal shift was 2.8 cm preoperatively and 0.9 cm postoperatively. The coronal Cobb angle reduced from 8.8° preoperatively to 2.8° postoperatively. On postoperative computed tomography, all patients had interval development of bridging bone across the surgical level through or around the cage. None of them developed cage migration or subsidence. Patients with irregular bony destruction due to diskitis/osteomyelitis may benefit from patient-specific cages for spinal reconstruction to address spinal instability and deformity.