Vertebral Plates Research Articles

Skill-Learning-Based Trajectory Planning for Robotic Vertebral Plate Cutting: Personalization Through Surgeon Technique Integration and Neural Network Prediction

In robotic-assisted laminectomy decompression, stable and precise vertebral plate cutting remains challenging due to manual dependency and the absence of adaptive skill-learning mechanisms. This paper presents an advanced robotic vertebral plate-cutting system that leverages patient-specific anatomical variations and replicates the surgeon’s cutting technique through a trajectory parameter prediction model. A spatial mapping relationship between artificial and patient vertebrae is first established, enabling the robot to mimic surgeon-defined trajectories with high accuracy. The robotic system’s trajectory planning begins with acquiring point cloud data of the vertebral plate, which undergoes preprocessing, Non-Uniform Rational B-Splines (NURBS) fitting, and parametric discretization. Using the processed data, a spatial mapping method translates the surgeon’s cutting path to the robotic coordinate system, with simulation validating the trajectory’s adherence to surgical requirements. To further enhance the accuracy and stability of trajectory planning, a Backpropagation(BP) neural network is implemented, providing predictive modeling for trajectory parameters. The analysis and training of the neural network confirm its effectiveness in capturing complex cutting trajectories. Finally, experimental validation, involving an artificial vertebral body model and cutting trials on patient vertebrae, demonstrates the proposed method’s capability to deliver enhanced cutting precision and stability. This skill-learning-based, personalized trajectory planning approach offers significant potential for improving the safety and quality of orthopedic robotic surgeries.

Optimization and control of robotic vertebral plate grinding: Predictive modeling, parameter optimization, and fuzzy control strategies for minimizing bone damage in laminectomy procedures.

During the robotic grinding of vertebral plates in high-risk laminectomy procedures, programmed operations may inadvertently induce force or temperature-related damage to the bone tissue. Therefore, it is imperative to explore a control methodology aimed at minimizing such damage during the robotic grinding of vertebral plate cortical bone, contingent upon optimal grinding parameters. Initially, predictive models for both the grinding force and temperature of vertebral plate cortical bone were developed using the response surface design (RSD) methodology. Subsequently, employing the satisfaction function approach, multi-objective parameter optimization of these predictive models was conducted to ascertain the optimal combination of parameters conducive to low-damage grinding. The optimum grinding parameters identified were a speed of 6000 r/min, a depth of grind of 0.4 mm, and a feed rate of 3.8 mm/s. Moreover, a multi-layer adaptive fuzzy control strategy was devised, and a corresponding multi-layer adaptive fuzzy controller (MFLC) was then implemented to dynamically adjust the grinding feed speed. The efficacy of this control module was corroborated through Simulink simulations. Simulation results demonstrated that the magnitude of the grinding force fluctuated within the range of 2.2-2.6 N after FLC control, while the fluctuation range of the grinding force was limited to 2.2-2.48 N after MFLC control. This indicates that MFLC control brings the force closer to the target expectation value of 2.39 N compared with FLC control. Finally, the dynamic fuzzy control method predicated on optimal grinding parameters was validated through experimental porcine spine grinding conducted on a robotic vertebral plate grinding platform.

Trajectory Planning and Adaptive Fuzzy PID Control for Precision in Robotic Vertebral Plate Cutting: Addressing Force Dynamics and Deformation Challenges

This study explores trajectory planning and cutting force control for spinal surgical robots, focusing on managing cutting deformation and vibration during vertebral plate cutting—a critical challenge in robotic spinal surgery. Through theoretical analysis, simulation, and experimental validation, the research addresses the complexities of cutting force dynamics and the associated deformations. A dynamic equation for vertebral plate cutting is established, providing a theoretical foundation for trajectory planning. A new trajectory planning method using B-spline curves and an interpolation point constraint formula is introduced, enabling precise robot trajectory control. Additionally, an adaptive fuzzy PID control strategy with force feedback is proposed to dynamically adjust the feed rate, effectively suppressing cutting deformation and vibration in real time. Simulations and experiments validate the effectiveness of these methods in reducing force fluctuations and enhancing control stability. The findings offer valuable guidance for improving the performance and safety of spinal surgery robots, optimizing their trajectories, incorporating dynamic sensing, and enhancing safety controls. Future research should focus on refining control strategies for more complex surgical scenarios and validating their applicability under conditions closer to actual surgical environments. This work provides theoretical and practical insights into advancing robotic spinal surgery, contributing to better surgical outcomes and patient safety.

Personalized 3D Printing of Artificial Vertebrae: A Predictive Bone Density Modeling Approach for Robotic Cutting Applications

Robotic vertebral plate cutting poses significant challenges due to the complex bone structures of the lumbar spine, which consist of varying densities in cortical and cancellous regions. This study addresses these challenges by developing a predictive model for robotic vertebral plate cutting force and bone quality recognition through the fabrication of artificial vertebrae with controlled, consistent bone density. To address the variability in bone density between cortical and cancellous regions, CT data are utilized to predict target bone density, serving as a foundation for determining the optimal 3D printing process parameters. The proposed methodology integrates a Response Surface Methodology (RSM), Back Propagation (BP) neural network, and genetic algorithm (GA) to systematically evaluate the effects of key process parameters, such as the filling density, material flow rate, and layer thickness, on the printed vertebrae’s density. A one-factor experimental approach and RSM-based central composite design are applied to build an initial bone density prediction model, followed by Sobol’s sensitivity analysis to quantify the influence of each parameter. The GA-BP neural network model is then employed to rapidly and accurately identify optimal printing parameters for different bone layer densities. The resulting optimized models are used to fabricate personalized artificial lumbar vertebrae, which are subsequently validated through robotic cutting experiments. This research not only contributes to the advancement in personalized 3D printing technology but also provides a reliable framework for developing patient-specific surgical planning models in robot-assisted orthopedic surgery.

Effect of screw insertion depth into fractured vertebrae in the treatment of thoracolumbar fractures

PurposeThe study’s objective was to assess the effect of the screw insertion depth into fractured vertebrae in treating thoracolumbar fractures.Materials and methodsThis was a retrospective analysis of 92 patients with thoracolumbar fractures from December 2018 to February 2020. Patients had AO type A2, A3 thoracolumbar fractures. The patients were divided into two groups according to the screw insertion depth. The vertebral wedge angle (VWA), Cobb angle (CA), anterior vertebral body height (AVBH), middle vertebral body height (MVBH), visual analog scale (VAS) score, and Oswestry Disability Index (ODI) were compared preoperatively and at one week and 12 months postoperatively. The correlation between Vertebral height loss and potential risk factors, such as sex, age, BMD and BMI was evaluated.ResultsCompared with the preoperative data, the postoperative clinical and radiographic findings were significantly different in both groups, But no significant difference between the two groups at 1 week. At 1 year postoperatively, there was a significant difference in the CA (p < 0.0001), VWA (p = 0.047), AVBH (p < 0.0001), MVBH (p < 0.0001), VAS score (p < 0.0001), and ODI (p < 0.0001) between the two groups, Except for age, bone density and other influencing factors the long screw group had better treatment results than the short screw group.ConclusionA longer screw provides greater grip on the fractured vertebral body and stronger support to the vertebral plate. The optimal screw placement depth exceeds 60% of the vertebral body length on the lateral view.

7598 A Humanized PTH Receptor Mouse Model Of Eiken Syndrome: Delayed Bone Mineralization Caused By A Receptor C-tail Truncation

Abstract Disclosure: J. Höppner: None. P. Hanna: None. M.N. Wein: None. H. Jueppner: None. T.J. Gardella: None. R. Civitelli: None. I.A. Portales-Castillo: None. Abstract The parathyroid hormone receptor-1 (PTH1R) plays a key role in bone development and acts in the growth plates in response to PTHrP ligand. Eiken syndrome is characterized by a delay in bone mineralization and is caused by homozygous PTH1R mutations. One such mutation, R485X, truncates the receptor's C-tail and removes serine phosphorylation sites involved in βarrestin binding. In HEK293 cells, R485X-hPTH1R exhibits deficient interaction with βarrestin and increased cAMP signaling both basally and in response to PTHrP (Portales-Castillo et al., Comms. Biology 2023). To understand how the R485X mutation causes delayed bone mineralization, we generated humanized R485X-hPTH1R knock-in mice. Homozygous hPTH1RR485X/R485X mice closely recapitulate the delayed bone mineralization seen in Eiken patients, as skeletal whole mount preparations from neonatal mutant mice showed reduced Alizarin red staining compared to WT controls, and metatarsal explants from the mutant mice showed a pronounced absence of mineralized bone. Tails of hPTH1RR485X/R485X mice were ∼50% shorter than those of WT littermates, and H&amp;E-stained sections revealed only proliferative chondrocytes in the growth plates of mutant mice. This delay in growth plate chondrocyte maturation in hPTH1RR485X/R485X mice resolved with age, although older long bones and tails remained smaller in size than WT controls (Höppner et al. Presented at ASBMR 2023).Based on our in vitro findings and initial mouse characterization, we reasoned that the phenotype of Eiken mice may be explained by increased PTHrP/PTH1R signaling in growth plate chondrocyte. The class IIa histone deacetylase HDAC4 suppresses chondrocyte maturation downstream of PTH1R signaling. Therefore, we generated compound mutant mice bearing both Hdac4 deletion and the mutant R485X PTH1R allele. Indeed, Hdac4 deletion largely rescued the mineralization defect apparent in metatarsals of P1 hPTH1RR485X/R485X mice. We then assessed the contribution of endogenous PTHrP to the Eiken-like phenotype by generating hPTH1RR485X/R485X/PTHrPflox/+/Col2-Cre(tg) mice. Remarkably, these mice exhibit approximately the same tail lengths as hPTH1R-WT littermate controls, indicating that reduced PTHrP production can rescue the effects of homozygosity for R485X-PTH1R. In line, vertebral growth plates of the rescued mice exhibited normal zones of chondrocytes, including hypertrophic cells. The overall results support a disease mechanism for Eiken syndrome by which excess cAMP signaling by PTH1R-R485X, as induced in part by endogenous PTHrP, results in delayed chondrocyte differentiation and bone mineralization. Further studies employing βarr1/2-KO mice may help shed light on the specific roles of βarrestins in growth plate development by PTH1R in Eiken syndrome. Presentation: 6/3/2024

Application of ultrasonic bone scalpel system for laminectomy and posterior longitudinal ligament ossification block release combined with dekyphosis orthopedic surgery in treatment of multisegmental thoracic ossification of posterior longitudinal ligament

To explore the safety and effectiveness of multisegmental thoracic ossification of posterior longitudinal ligament (T-OPLL) treated by laminectomy, posterior longitudinal ligament ossification block release combined with dekyphosis orthopedic surgery using ultrasonic bone scalpel system. The clinical data of 8 patients with multisegmental T-OPLL treated with laminectomy, posterior longitudinal ligament ossification block release combined with dekyphosis orthopedic surgery using ultrasonic bone scalpel system between January 2020 and April 2023 was retrospectively analyzed. There were 3 males and 5 females; the age ranged from 41 to 67 years, with a mean of 57.1 years. The disease duration ranged from 3 to 74 months, with a mean of 33.4 months. Symptoms were progressive numbness and weakness of both lower limbs, unsteady walking, chest and back pain in 3 cases, and urinary and bowel dysfunction in 5 cases; 7 cases showed increased muscle strength of the lower limbs, hyperreflexia of the tendons, and a positive Babinski sign, and 1 case showed decreased muscle strength of the lower limbs, decreased skin sensation, decreased knee and Achilles tendon reflexes, and a negative pathologic sign. Multisegmental posterior longitudinal ligament ossification of thoracic spine was found in 8 cases, with 4-8 segments of ossification, and in 5 cases with multisegmental ossification of the ligamentum flavum. The preoperative Japanese Orthopaedic Association (JOA) thoracic spinal function score was 4.3±0.9, the visual analogue scale (VAS) score was 6.9±1.0, and the the kyphotic Cobb angle of the stenosis segment was (34.62±10.76)°. The operation time, intraoperative blood loss, and complications were recorded. VAS score was used to evaluate the back pain, JOA score was used to evaluate the thoracic spinal cord function and the JOA improvement rate was calculated, and the kyphotic Cobb angle of the stenosis segment was measured and the Cobb angle improvement rate was calculated. The operation time ranged from 210 to 340 minutes, with a mean of 271.62 minutes; intraoperative blood loss ranged from 900 to 2 100 mL, with a mean of 1 458.75 mL; the number of resected vertebral plates ranged from 4 to 8, with a mean of 6.1; dural tears and cerebrospinal fluid leakage occurred in 3 cases, and the incisions healed by first intention. All 8 cases were followed up 12-26 months, with a mean of 18.3 months. There was no complication such as loosening of internal fixator, breakage of screws and rods, and no significant progress of ossification. At last follow-up, the VAS score was 1.4±0.7, the JOA thoracic spinal function score was 9.8±0.7, and the the kyphotic Cobb angle of the stenosis segment was (22.12±8.28)°, all of which significantly improved when compared with preoperative ones ( t=11.887, P<0.001; t=13.015, P<0.001; t=7.395, P<0.001). The JOA improvement rate was 81.06%±10.93%, of which 5 cases were rated as excellent and 3 cases as good; the Cobb angle improvement rate was 36.51%±14.20%. Laminectomy, posterior longitudinal ligament ossification block release combined with dekyphosis orthopedic surgery using ultrasonic bone scalpel system is a safe, effective, and simple method for the treatment of multisegmental T-OPLL, which is a feasible option.

Spinal Neuronavigation for Lumbar Plate Fixation in Miniature Breed Dogs.

The main aim of this pilot study was to assess the feasibility of spinal neuronavigation for plate fixation of lumbar vertebrae in miniature breed dogs using a surgical navigation system in combination with a custom-made reference array. This was an experimental cadaveric study in five miniature breed dogs. A 4-hole locking plate with four 2.0-mm locking screws was placed on two adjacent lumbar vertebrae using a neuronavigation system consisting of a mobile cone beam computed tomography linked to a navigation system. The procedure was performed by a novice surgeon. The plate and screw positions were assessed for surgical safety using predefined criteria. Surgical accuracy was determined by the deviation of entry and exit points between pre- and postoperative images. A total of five plates and 20 screws were placed. In 85% (17/20), screws were placed appropriately. The median entry point deviation was 1.8 mm (range: 0.3-3.7) and the median exit point deviation was 1.6 mm (range: 0.6-5). Achievement of surgical accuracy in the placement of screws for fixation of lumbar vertebral plates in small breed dogs using neuronavigation with a custom-made reference array by a novice surgeon resulted in surgical safe plate placement in four of the five cadavers. Therefore, we judge the method as promising, however, further studies are necessary to allow the transfer of image-guided navigation for lumbar plate fixation into the clinic.

Imaging anatomy study related to unilateral biportal endoscopic lumbar spine surgery.

To provide lumbar spine anatomical parameters relevant to the UBE technique and explore their intraoperative application. CT imaging data processed by Mimics for parametric measurements, including laminar abduction angle (LAA), laminar slope angle (LSA), minimum laminar height (MLH), distance between the inferior margin of the lamina and attachment of the ligamentum flavum onto the cephalad lamina (DLL), distance between the initial point and the middle of the articular process (DIA), and distance from the inferior margin of the lamina to the inferior border of the vertebral body (DLV), and were manually measured. LAA and DIA gradually increase from L1 to L5. At L1, the DIA is approximately the length of 2 drill bits with a diameter of 3mm (male: 7.77 ± 1.39mm, female: 7.22 ± 1.09mm), while at L5, it can reach the length of 4-5 drill bits (male: 14.96 ± 2.24mm, female: 13.67 ± 2.33mm). MLH, DLL, and DLV reach their maximum values at the L3 and decrease toward the cranial and caudal ends. The DLL is smallest at L5 (male: 9.58 ± 1.90mm, female: 9.38 ± 2.14mm), equivalent to the length of 3 drill bits, while the DLL at L3 is the length of 4-5 drill bits (male: 14.17 ± 2.13mm, female: 14.01 ± 2.07mm). Referring to the drill diameter during surgery can mark the extent of laminotomy. The characteristics of vertebral plate angles at different lumbar levels can provide references for preoperative incision design.

A comparative analysis of TonEBP conditional knockout mouse models reveals inter-dependency between compartments of the intervertebral disc.

Interactions between notochord and sclerotome are required for normal embryonic spine patterning, but whether the postnatal derivatives of these tissues also require interactions for postnatal intervertebral disc (IVD) growth and maintenance is less established. We report here the comparative analysis of four conditional knockout mice deficient for TonEBP, a transcription factor known to allow cells to adapt to changes in extracellular osmotic pressure, in specific compartments of the IVD. We show that TonEBP deletion in nucleus pulposus (NP) cells does not affect their survival or aggrecan expression, but promoted cell proliferation in the NP and in adjacent vertebral growth plates (GPs). In cartilage end plates/GPs, TonEBP deletion induced cell death, but also structural alterations in the adjacent NP cells and vertebral bodies. Embryonic or postnatal TonEBP loss generated similar IVD changes. In addition to demonstrating the requirement of TonEBP in the different compartments of the IVD, this comparative analysis uncovers the in vivo interdependency of the different IVD compartments during the growth of the postnatal IVD-vertebral units.

Experimental study of tetramethylpyrazine-loaded electroconductive hydrogel on angiogenesis and neuroprotection after spinal cord injury

To explore the mechanisms for repairing spinal cord injury (SCI) with tetramethylpyrazine-loaded electroconductive hydrogel (hereinafter referred to as "TGTP"). A total of 72 female Sprague-Dawley rats were randomly divided into 4 groups: sham operation group (group A), SCI group (group B), SCI+electroconductive hydrogel group (group C), and SCI+TGTP group (group D). Only the vertebral plate was removed in group A, while the remaining groups were subjected to a whole transection model of spinal cord with a 2 mm gap in the lesions. The recovery of hindlimb motor function was evaluated by Basso, Beattie, Bresnahan (BBB) score and modified Rivlin-Tator inclined plate test before operation and at 1, 3, 7, 14, and 28 days after operation, respectively. Animals were sacrificed at 7 days and 28 days after modeling. Neovascularisation was observed by immunofluorescence staining of CD31 and the expression levels of angiopoietin 1 (Ang-1) and Tie-2 were assessed by Western blot assay. At 28 days postoperatively, the expression levels of pro-angiogenic related proteins, including platelet-derived growth factor B (PDGF-B), PDGF receptor β (PDGFR-β), vascular endothelial growth factor A (VEGF-A), and VEGF receptor 2 (VEGFR-2), were also assessed by Western blot. The fibrous scar in the injured area was assessed using Masson staining, while neuronal survival was observed through Nissl staining. Furthermore, LFB staining was utilized to detect myelin distribution and regeneration. Immunofluorescence and Western blot assay were employed to evaluate the expression of neurofilament 200 (NF200). The hindlimb motor function of rats in each group gradually recovered from the 3rd day after operation. The BBB score and climbing angle in group D were significantly higher than those in group B from 3 to 28 days after operation, and significantly higher than those in group C at 14 days and 28 days after operation ( P<0.05). Masson staining showed that the collagen volume fraction in groups B-D were significantly higher than that in group A, and that in group D was significantly lower than that in groups B and C ( P<0.05); a small amount of black conductive particles were scattered at the broken end in group D, and the surrounding collagen fibers were less than those in group C. Nissl and LFB staining showed that the structure of neurons and myelin sheath in the injured area of spinal cord in group D was relatively complete and continuous, and the number of Nissl bodies and the positive area of myelin sheath in group D were significantly better than those in groups B and C ( P<0.05). NF200 immunofluorescence staining and Western blot assay results showed that the relative expression of NF200 protein in group D was significantly higher than that in groups B and C ( P<0.05). CD31 immunofluorescence staining showed that the fluorescence intensity of group D was better than that of groups B and C at 28 days after operation, and tubular or linear neovascularization could be seen. The relative expressions of Ang-1 and Tie-2 proteins in group D were significantly higher than those in groups B and C at 7 and 28 days after operation ( P<0.05). The relative expressions of PDGF-B and PDGFR-β proteins in group D were significantly higher than those in groups B and C, and group B was significantly higher than group C at 28 days after operation ( P<0.05). The relative expressions of VEGF-A and VEGFR2 proteins in group D were higher than those in groups B and C, showing significant difference when compared with group B ( P<0.05), but only the expression of VEGF-A protein was significantly higher than that in group C ( P<0.05). There was significant difference only in VEGFR-2 protein between groups B and C ( P<0.05). TGTP may enhance the revascularization of the injured area and protect the neurons, thus alleviating the injury of spinal cord tissue structure and promoting the recovery of neurological function after SCI in rats.

Biomechanical evaluation on a new type of vertebral titanium porous mini-plate and mechanical comparison between cervical open-door laminoplasty and laminectomy: a finite element analysis.

Objective: Compare the spine's stability after laminectomy (LN) and laminoplasty (LP) for two posterior surgeries. Simultaneously, design a new vertebral titanium porous mini plate (TPMP) to achieve firm fixation of the open-door vertebral LP fully. The objective is to enhance the fixation stability, effectively prevent the possibility of "re-closure," and may facilitate bone healing. Methods: TPMP was designed by incorporating a fusion body and porous structures, and a three-dimensional finite element cervical model of C2-T1 was constructed and validated. Load LN and LP finite element models, respectively, and analyze and simulate the detailed processes of the two surgeries. It was simultaneously implanting the TPMP into LP to evaluate its biomechanical properties. Results: We find that the range of motion (ROM) of C4-C5 after LN surgery was greater than that of LP implanted with different plates alone. Furthermore, flexion-extension, lateral bending, and axial rotation reflect this change. More noteworthy is that LN has a much larger ROM on C2-C3 in axial rotation. The ROM of LP implanted with two different plates is similar. There is almost no difference in facet joint stress in lateral bending. The facet joint stress of LN is smaller on C2-C3 and C4-C5, and larger more prominent on C5-C6 in the flexion-extension. Regarding intervertebral disc pressure (IDP), there is little difference between different surgeries except for the LN on C2-C3 in axial rotation. The plate displacement specificity does not significantly differ from LP with vertebral titanium mini-plate (TMP) and LP with TPMP after surgery. The stress of LP with TPMP is larger in C4-C5, C5-C6. Moreover, LP with TMP shows greater stress in the C3-C4 during flexion-extension and lateral bending. Conclusion: LP may have better postoperative stability when posterior approach surgery is used to treat CSM; at the same time, the new type of vertebral titanium mini-plate can achieve almost the same effect as the traditional titanium mini-plate after surgery for LP. In addition, it has specific potential due to the porous structure promoting bone fusion.

Intervertebral disc-intrinsic Hedgehog signaling maintains disc cell phenotypes and prevents disc degeneration through both cell autonomous and non-autonomous mechanisms

Intervertebral disc degeneration is closely related to abnormal phenotypic changes in disc cells. However, the mechanism by which disc cell phenotypes are maintained remains poorly understood. Here, Hedgehog-responsive cells were found to be specifically localized in the inner annulus fibrosus and cartilaginous endplate of postnatal discs, likely activated by Indian Hedgehog. Global inhibition of Hedgehog signaling using a pharmacological inhibitor or Agc1-CreERT2-mediated deletion of Smo in disc cells of juvenile mice led to spontaneous degenerative changes in annulus fibrosus and cartilaginous endplate accompanied by aberrant disc cell differentiation in adult mice. In contrast, Krt19-CreER-mediated deletion of Smo specifically in nucleus pulposus cells led to healthy discs and normal disc cell phenotypes. Similarly, age-related degeneration of nucleus pulposus was accelerated by genetic inactivation of Hedgehog signaling in all disc cells, but not in nucleus pulposus cells. Furthermore, inactivation of Gli2 in disc cells resulted in partial loss of the vertebral growth plate but otherwise healthy discs, whereas deletion of Gli3 in disc cells largely corrected disc defects caused by Smo ablation in mice. Taken together, our findings not only revealed for the first time a direct role of Hedgehog-Gli3 signaling in maintaining homeostasis and cell phenotypes of annuls fibrosus and cartilaginous endplate, but also identified disc-intrinsic Hedgehog signaling as a novel non-cell-autonomous mechanism to regulate nucleus pulposus cell phenotype and protect mice from age-dependent nucleus pulposus degeneration. Thus, targeting Hedgehog signaling may represent a potential therapeutic strategy for the prevention and treatment of intervertebral disc degeneration.

The new clinical classification of metastatic spinal malignancies serves as a vital reference for surgical management: a retrospective case-control study

BackgroundIt is commonly accepted that surgical treatment is an essential component of the comprehensive management of metastatic spinal malignancies. However, up until now, the clinical classification of metastatic spinal malignancies has not been well-structured.MethodsAfter IRB approval, 86 patients with metastatic spinal malignancies were adopted. According to the vascular distribution, stability of vertebrae, and degree of nerve compression, metastatic spinal malignancies can be classified into five types. Tumors classified as type I typically appear in the vertebral body. Type II tumors are those that develop in the transverse processes, superior and inferior articular processes, and spinal pedicles. Type III denotes malignancies that are present in the spinous process and vertebral plate. Types IVa and IVb are included in type IV. Type IVa combines type I and type II, whereas type IVb combines type II and type III. Type V tumors are those of types I, II, and III that co-occur and spread in different directions into the spinal canal. 20 of included 86 patients who did not receive segmental arterial embolization were set as the non-embolization group. The embolization group included 24 patients who received segmental arterial embolization on both sides of the diseased vertebrae. 42 patients were included in the offending embolization group after receiving responsible arterial embolization. A surgical intervention was performed within 24 h following an embolization. Surgical intervention with the purpose of removing as much of the tumor as possible and providing an effective reconstruction of the spinal column.ResultsIn comparison with the non-embolization group and embolization group, the offending embolization group presented unique advantages in terms of bleeding volume (p<0.001), operation time (p<0.001), and local recurrence rate within 12 months (p=0.006).ConclusionBy significantly reducing surgical trauma and local recurrence rate (12 months), responsible arterial vascular embolization procedures together with associated surgical protocols developed on the basis of the clinical classification of metastatic spinal malignancies, are worthy of clinical dissemination.

Da Vinci Robotic Assistance for Anterolateral Lumbar Arthrodesis: Results of a French Multicentric Study

BackgroundDa Vinci® robot (DVR®) is today the most widely used robot in visceral, urological and gynecological surgery. Thanks to its minimally invasive approach, it has demonstrated its effectiveness and improved safety in these different disciplines. The aim of our study is to report its use in anterior approach of complex lumbar surgery. Material and MethodThis is a retrospective multicenter observational study. Ten robotic-assisted procedures were performed from March 2021 to May 2022. Six oblique lumbar interbody fusion (OLIF) procedures and four lumbar corporectomies were performed by anterolateral approach assisted by DVR®. The characteristics of the patients as well as the intra- and postoperative data were recorded. ResultsSix men and four women underwent surgery, with a mean age of 50.5 years and a BMI of 28.6 kg/m2. No vascular injuries were reported, and no procedures required conversion to open surgery. Mean surgical time were 219 minutes for 1-level-OLIF (3 patients), 286 minutes for 2-level-OLIF (3 patients), and 390 minutes for corporectomy (4 patients). Four patients experienced non-serious adverse events due to lumbar plexus nerve damage. One patient had a vertebral body plate fracture requiring posterior revision surgery, and one patient had a psoas hematoma requiring transfusion. No abdominal wall complications or surgical site infection were found. Seven patients were reviewed at 12 months, none had complications, and all showed radiological evidence of fusion. ConclusionThe use of DVR® in lumbar surgery allows a safe minimally invasive trans-peritoneal approach, but to date, it only allows hybrid procedures to be performed.

Dose-Effect of Proton and Photon Craniospinal Irradiation on Vertebral Growth in Pediatric Patients with Medulloblastoma

Craniospinal irradiation (CSI) directly damages vertebral growth plates causing skeletal dysplasia leading to reduced height in pediatric long-term survivors. The objective of this study is to quantify the adjusted effect of CSI on standing and sitting height by radiation dose and modality in children. Two hundred sixty-five patients (M/F 169/96) were treated at a single institution on a clinical and molecular risk-directed trial for medulloblastoma (NCT01878617) using proton or photon therapy. Three CSI dose regimens were evaluated: 15 Gy (n = 31), 23.4 Gy (n = 103), ≥36 Gy (n = 131). Vertebral body dose was limited to 18-20 CGE for 23.4 Gy or 36 Gy proton therapy. All patients received post-CSI protocol-specified chemotherapy. Non-parametric tests were applied for baseline patient comparison. Changes in growth over time were calculated using random coefficients models using patient-specific intercepts and slopes. Dose-effects were modeled for ages 5, 10, and 18 years. Age at CSI and race were similar between the three dose levels. Females most often received 23.4 Gy and males ≥36 Gy (p = 0.001). Higher CSI doses were associated with photon therapy (p<0.001). Median follow-up was 3 years (range 0.1-7.1). Annual growth rate was significantly different between 15 Gy (3.66 cm/year) and the higher dose levels of 23.4 Gy (2.81 cm/year, p = 0.0389) and ≥36 Gy (2.46 cm/year, p = 0.0032). Lower annual growth rate in females (vs. males, p = 0.0331) was observed in models for those aged 5 (-0.17 cm/year), 10 (-0.35 cm/year), and 18 years (-0.62 cm/year). In multivariate analysis, modelled annual growth rate was dose-dependent at ages 5 and 10 years. The differences were, respectively, 1.68 cm/year between 15 and 23.4 Gy (p = 0.0005) and 0.98 cm/year between 23.4 and ≥36 Gy (p = 0.0002), and 1.13 cm/year between 15 and 23.4 Gy (p = 0.0002) and 0.68 cm/year between 23.4 and ≥36 Gy (p = 0.0003). Radiation modality did not impact standing height over time significantly. Annual sitting height growth was 2.34, 1.67 and 1.1 cm/year for the three dose levels (p<0.0001-0.001). In the multivariate model, a 5-year-old receiving 15 or 23.4 Gy had similar annual sitting height growth, but not when 23.4 Gy was compared to ≥36 Gy (0.83 cm/year, p<0.0001). In a separate model for a patient aged 10 years, there was a difference comparing all CSI regimens (0.81 cm/year, p<0.0001, 15 vs 23.4 Gy; 0.54 cm/year, p = 0.0002, 23.4 vs ≥36 Gy). Sitting height growth was affected by CSI dose at age 18 years, with a difference of 2.2 cm/year between 15 vs 23.4 Gy (p = 0.0013), and no difference between 23.4 and ≥36 Gy. Annual growth rates show a dose-response relationship, independent of treatment modality. A dose-response in sitting height growth rate is seen at any age, while the annual standing height growth rate was only affected by CSI dose in 5- and 10-year-olds. While all CSI doses had a significant impact on the annual standing height, sitting height growth rates approximated normal values for those treated with a low CSI dose.

Exploring the micromorphological characteristics of adult lower cervical vertebrae based on micro-computed tomography

We will use micro-computed tomography to scan 31 sets of the adult lower cervical vertebrae (155 vertebrae) to observe the morphological characteristics and direction of trabeculae in the lower cervical vertebrae by outlining and reconstructing the regions of interest and to calculate the variation laws of the microstructure in the regions of interest to reveal their structural characteristics and weak areas. As a result, the images showed that the trabeculae in the lower cervical pedicle near the medial and lateral cortices were relatively dense, and their bone plates were lamellar. There were cavities between the superior and inferior articular processes where the ossification centers had not been absorbed after ossified. The lamellar trabeculae in the vertebral plates near the cortical bones were only 1–2 layers, extended and transformed into rod-shaped trabeculae in a radial shape toward the medullary space. The lamellar trabeculae of the vertebral plate extend over the spinous process near the cortical bone. The statistical results of the trabeculae's morphological parameters showed significant differences in bone volume fraction values among the four parts (P < 0.05). There were substantial differences in BS/BV, except for no differences between the pedicle and the vertebral plate (P < 0.05). There was a significant difference in trabecular pattern factor values between the articular process, the spinous process, and the vertebral plate (P < 0.05) and a significant difference between the pedicle, the spinous process, and the vertebral plate (P < 0.05). There were no significant differences in trabecular bone thickness and trabecular space values among the four parts (P < 0.05). The anatomical microstructural perspective confirms that the optimal choice is internal fixation via the pedicle. If using pedicle screws, the nail tract needs to be placed into the spinous process to increase its holding power and resistance to extraction.

Hematomyelia associated with coronavirus disease 2019: A rare case report.

Coronavirus disease 2019 (COVID-19) can damage the central nervous system. Although there have been reports of cerebral hemorrhage and infarction caused by COVID-19, hematomyelia due to COVID-19 has never been reported. A 40-year-old male was admitted to the hospital with positive nucleic acid detection for COVID-19 after experiencing fever for 2 weeks, urinary retention, fecal retention, and pain in both lower extremities for a week. The patient diagnosis was established using thoracic and lumbar magnetic resonance imaging (MRI). Contrast-enhanced thoracic and lumbar MRI revealed subdural (dorsal predominant) short T1 and slightly long T2 bands in the T12-S2 infundibular canal in the scan field, and the subdural hematoma was yet to be distinguished from other diseases. Spinal cord edema was observed in the left vertebral plate and facet joint of the T11 vertebral body, indicative of inflammation. The cerebrospinal fluid (CSF) was positive for COVID-19 nucleic acid. Antiinfection, immunomodulation, correction of acid-base balance and electrolyte disorders, improvement of circulation, nerve nutrition, and other symptomatic supportive treatments were administered to the patient. The patient symptoms significantly improved after 4 weeks of anti-infection and immunomodulatory therapy. Repeat thoracolumbar MRI revealed absorption of the spinal cord hematoma, and the patient was discharged from the hospital. To date, COVID-19-related hematomyelia has not been reported and anti-infective and immunomodulatory therapies may be effective. COVID-19 not only easily leads to brain injury but can also cause spinal cord injury and even spinal cord hemorrhage. When patients with COVID-19 experience symptoms and signs of spinal cord injury, spinal cord injury and bleeding caused by COVID-19 should be considered, and MRI and lumbar puncture should be performed as soon as possible to make a clear diagnosis.

Bone-to-Bone Ligament Preserving Laminoplasty with Ultrasonic Osteotome Assistance for Intraspinal Tumors: A Technical Note and Clinical Follow-Up.

Laminectomy has been widely used for intraspinal tumor resection. However, the tilted spinous process and narrow lateral laminae of the thoracic spine along with the hypertrophic ligamentum flavum of the lumbar spine pose certain problems for the laminae removal of the traditional laminectomy. We improved the laminectomy method with ultrasonic osteotome to treat thoracolumbar tumors and assessed its safety and superiority. A retrospective analysis was performed in 86 patients with thoracolumbar (T4-L5) spinal tumors treated by resection, including 44 with the lamina removed using the traditional method and 42 with the lamina removed using the bone-to-bone ligament preserving (BLP) laminoplasty, which preserves the posterior ligament complex. Age, sex, and tumor size, location, and depth were compared between the two groups. The length of incision and bone window, time to remove the vertebral lamina, and epidural effusion volume were recorded at 2 weeks after surgery in the two groups. Postoperative reexamination by magnetic resonance imaging (MRI) at 2 weeks and 3 months after surgery was compared with preoperative MRI to assess the change in vertebral lamina displacement. There were no statistical differences in age, sex, and tumor size, depth, or location between the two groups. The BLP laminectomy did not increase the risk of dural, spinal cord, or nerve injuries. The difference between the incision and tumor length, as well as the difference between the bone window and tumor length in the BLP laminectomy group, were smaller than those in the traditional laminectomy group, and the BLP laminectomy took less time compared to that of the traditional laminectomy (p < 0.05). There was no significant difference in the volume of epidural effusion between the two groups at 2 weeks postoperatively, or in the displacement of the returned vertebral plate observed in sagittal and axial positions. The same was true for the displacement at 3 months postoperatively in the axial position. However, the sagittal displacement in the BLP laminectomy group was smaller than that in the traditional laminectomy group (p < 0.05). The BLP laminectomy is safe for the resection of thoracolumbar spinal canal tumors. It is less traumatic and faster, with less displacement of the returned lamina, resulting in a stable repair of the spine.

3D Printing Model of a Patient's Specific Lumbar Vertebra.

Selective dorsal rhizotomy (SDR) is a difficult, risky, and sophisticated operation, in which a laminectomy should not only expose an adequate surgical field of view but also protect the patient's spinal nerves from injury. Digital models play an important role in the pre-and intra-operation of SDR, because they can not only make doctors more familiar with the anatomical structure of the surgical site, but also provide precise surgical navigation coordinates for the manipulator. This study aims to create a 3D digital model of a patient-specific lumbar vertebra that can be used for planning, surgical navigation, and training of the SDR operation. The 3D printing model is also manufactured for more effective work during these processes. Traditional orthopedic digital models rely almost entirely on computed tomography (CT) data, which is less sensitive to soft tissues. Fusion of the bone structure from CT and the neural structure from magnetic resonance imaging (MRI) is the key element for the model reconstruction in this study. The patient's specific 3D digital model is reconstructed for the real appearance of the surgical area and shows the accurate measurement of inter-structural distances and regional segmentation, which can effectively help in the preoperative planning and training of SDR. The transparent bone structure material of the 3D-printed model allows surgeons to clearly distinguish the relative relationship between the spinal nerve and the vertebral plate of the operated segment, enhancing their anatomical understanding and spatial sense of the structure. The advantages of the individualized 3D digital model and its accurate relationship between spinal nerve and bone structures make this method a good choice for preoperative planning of SDR surgery.