Virtual reality-based surgical planning simulator for tumorous resection in FreeForm Modeling: an illustrative case of clinical teaching.

The importance of virtual reality (VR) has been emphasized by many medical studies, yet it has been relatively under-applied to surgical operation. This study characterized how VR has been applied in clinical education and evaluated its tutorial utility by designing a surgical model of tumorous resection as a simulator for preoperative planning and medical tutorial. A 36-year-old male patient with a femoral tumor who was admitted to the Affiliated Jiangmen Traditional Chinese Medicine Hospital was randomly selected and scanned by computed tomography (CT). The data in digital imaging and communications in medicine (*.DICOM) format were imported into Mimics to reconstruct a femoral model, and were generated to the format of *.stl executing in the computer-aided design (CAD) software SenSable FreeForm Modeling (SFM). A bony tumor was simulated by adding clay to the femur, the procedure of tumorous resection was virtually performed with a toolkit called Phantom, and its bony defect was filled with virtual cement. A 3D workspace was created to enable the individual multimodality manipulation, and a virtual operation of tumorous excision was successfully carried out with indefinitely repeated running. The precise delineation of surgical margins was shown to be achieved with expert proficiency and inexperienced hands among 43 of 50 participants. This simulative educator presented an imitation of high definition, those trained by VR models achieved a higher success rate of 86% than the rate of 74% achieved by those trained by conventional methods. This tumorous resection was repeatably handled by SFM, including the establishment of surgical strategy, whereby participants felt that respondent force feedback was beneficial to surgical teaching programs, enabling engagement of learning experiences by immersive events which mimic real-world circumstances to reinforce didactic and clinical concepts.

Percutaneous Bilateral Endoscopic Lumbar Interbody Fusion: Technical Note and Preliminary Results.

Objective: The purpose of this study was to investigate the feasibility and clinical efficacy of the percutaneous bilateral endoscopy technique (microendoscopic trans-Kambin's triangle lumbar interbody fusion + percutaneous endoscopic transforaminal decompression of the lumbar spinal canal, ME-TKT-LIF+ PETD) in the treatment of lumbar degenerative diseases. Methods: From May 2016 to September 2018, 29 patients (16 males and 13 females) who suffered from neurologic symptoms due to degenerative lumbar spine disease and underwent percutaneous bilateral endoscopy technique were enrolled. A microendoscope was used for fusion, and a percutaneous endoscope was used for spinal canal decompression. These patients' perioperative and clinical outcome-related parameters were collected and analyzed. Results: The mean intraoperative blood loss was 72.8 ± 40.6 ml, the operation time was 87.1 ± 10.1 min, the postoperative ambulatory time was 1.69 ± 1.0 days, the hospital stay was 2.6 ± 1.3 days, and the follow-up period was 22.34 ± 4.2 months. The visual analog scale (VAS) and the Oswestry disability index (ODI) were significantly improved at the early postoperative and last follow-up, respectively. According to the modified MacNab criteria, 11 (11/29) cases were rated as excellent, 15 (15/29) as good, and 3 (3/29) as fair, and the excellent and good rate was 89.7%. Twenty-eight (28/29) cases demonstrated solid fusion, and the fusion rate was 96.6%. Conclusion: The percutaneous bilateral endoscopy technique is safe and feasible in the treatment of lumbar degenerative diseases, with the advantage that more normal anatomical structures are preserved. It is an optional method of lumbar interbody fusion.

Screws Fixation for Oblique Lateral Lumbar Interbody Fusion (OL-LIF): A Finite Element Study.

BACKGROUND: The combination of screw fixation and cage can provide stability in lumbar interbody fusion (LIF), which is an important technique to treat lumbar degeneration diseases. As the narrow surface cage is developed in oblique lateral lumbar interbody fusion (OL-LIF), screw fixation should be improved at the same time. We used the finite element (FE) method to investigate the biomechanics response by three different ways of screw fixation in OL-LIF. METHODS: Using a validated FE model, OL-LIF with 3 different screw fixations was simulated, including percutaneous transverterbral screw (PTVS) fixation, percutaneous cortical bone trajectory screw (PCBTS) fixation, and percutaneous transpedical screw (PPS) fixation. Range of motion (ROM), vertebral body displacement, cage displacement, cage stress, cortical bone stress, and screw stress were compared. RESULTS: ROM in FE models significantly decreased by 84-89% in flexion, 91-93% in extension, 78-89% in right and left lateral bending, and 73-82% in right and left axial rotation compared to the original model. The maximum displacement of the vertebral body and the cage in six motions except for the extension of model PTVS was the smallest among models. Meanwhile, the model PTVS had the higher stress of screw-rods system and also the lowest stress of cage. In all moments, the maximum stresses of the cages were lower than their yield stress. CONCLUSIONS: Three screw fixations can highly restrict the surgical functional spinal unit (FSU). PTVS provided the better stability than the other two screw fixations. It may be a good choice for OL-LIF.

Biomechanical analysis for five fixation techniques of Pauwels-III fracture by finite element modeling.

BACKGROUND AND OBJECTIVES: There are many fixation methods for Pauwels- III fracture, the most common implants are Locking Plate (LP), Dynamic Hip Screw (DHS), Multiple Lag Screw (MLS), and mixed fixture (DHS+MLS) implants, the common procedure is HemiArthroplasty (HA). However, how these fixtures biomechanically function is not clear. The aims of this study are to compare the mechanical behaviors of these five implants by finite element modeling and determinate the most suitable procedure for individuals with Pauwels- III fractures. METHODS: We gathered 20 sets of femur images from CT scans in the *.dicom format first, and then processed them by using reverse engineering software programs, such as Mimics, Geomagic Studio, UG-8, Pro-Engineer and HyperMesh. Finally, we assembled and analyzed the five types of fixture models, the LP, DHS, MLS, DHS+LS and HA models, by AnSys. RESULTS: These numerical models of Pauwels III fractures, including fixators and a simulative HA, were validated by a previous study and a cadaver test. Our analytical findings include the following: the displacements of all fixtures were between 0.3801 and 1.0834 mm, and the differences were not statistically significantly different; the resulting average peaks in stress were e(Ha) = 43.859 ≤ d(LP) = 60.435 ≤ b(MLS) = 68.678 < c(LS+DHS) = 98.478 < a(DHS) = 248.595 in Mpa, indicating that the stress of DHS and DHS+LS are greater than those of LP, HA and MLS, while the last 3 models were not significantly different. CONCLUSIONS: To optimize the treatment for Pauwels III factures clinically, HA and LP should be proposed.

A novel narrow surface cage for full endoscopic oblique lateral lumbar interbody fusion: A finite element study.

OBJECTIVE: To evaluate the mechanical response of a narrow surface cage that we designed for full endoscopic oblique lateral lumbar interbody fusion (FE-OL-LIF). METHODS: A finite element (FE) model of lumbar spine was developed and validated. To simulate the FE-OL-LIF, the functional spinal unit (FSU) L4-L5 was assembled with a narrow surface polyetheretherketone (PEEK) cage, two rods and four screws. 500N load combined with 7.5Nm moment was applied to the surgical models. Effect of the cage width on the stress was studied. RESULTS: Range of motion (ROM) in the surgical models significantly decreased by 88% in flexion, 91% extension, 85% in right and left lateral bending, 75% in right and left axial rotation as compared to the intact model. Width of the cage slightly decreased the ROM in all loading scenarios. Flexion produced the highest stress in the cages and endplates. In all loading cases, the maximum stresses of cages and endplates were both lower than their yield stress. CONCLUSIONS: In engineering analysis, the novel narrow-surface cage had a strength to support spine activities. 9 mm width cage was recommended in FE-OL-LIF. This study provided engineering evidence and technical advice to improve the design of minimally invasive cage. Fatigue test and cadaver trial shall be improved.

Scalable Generation of Mesenchymal Stem Cells from Human Embryonic Stem Cells in 3D.

Human embryonic stem cell (hESC) derived mesenchymal stem cells (EMSC) are efficacious in treating a series of autoimmune, inflammatory, and degenerative diseases in animal models. However, all the EMSC derivation methods reported so far rely on two-dimensional (2D) culture systems, which are inefficient, costive and difficult for large-scale production. HESC, as an unlimited source, can be successively propagated in spheroids. Here, we demonstrate that hESC spheroids can directly differentiate into MSC spheroids (EMSCSp) within 20 days in one vessel without passaging and the system is scalable to any desired size. EMSCSp can further differentiate into osteocytes and chondrocytes in spheres or demineralized bone matrix. EMSCSp also retains immune-modulatory effects in vitro and therapeutic effects on two mouse models of colitis after dissociation. Compared to EMSC differentiated in monolayer, EMSCSp-derived cells have faster proliferation and higher yield and develop less apoptosis and slower senescence. Thus, the 3D differentiation system allows simple, cost-effective, and scalable production of high-quality EMSC and subsequently bone and cartilage tissues for therapeutic application.

Design of mulitlevel OLF approach ("V"-shaped decompressive laminoplasty) based on 3D printing technology.

PURPOSE: To introduce a new surgical approach to the multilevel ossification of the ligamentum flavum (OLF) aided by three-dimensional (3D) printing technology. METHODS: A multilevel OLF patient (male, 66 years) was scanned using computed tomography (CT). His saved DICOM format data were inputted to the Mimics14.0 3D reconstruction software (Materialise, Belgium). The resulting 3D model was used to observe the anatomical features of the multilevel OLF area and to design the surgical approach. At the base of the spinous process, two channels were created using an osteotomy bilaterally to create a "V" shape to remove the bone ligamentous complex (BLC). The decompressive laminoplasty using mini-plate fixation was simulated with the computer. The physical model was manufactured using 3D printing technology. The patient was subsequently treated using the designed surgery. RESULT: The operation was completed successfully without any complications. The operative time was 90 min, and blood loss was 200 ml. One month after the operation, neurologic function was recovered well, and the JOA score was improved from 6 preoperatively to 10. Postoperative CT scanning showed that the OLF was totally removed, and the replanted BLC had not subsided. CONCLUSION: 3D printing technology is an effective, reliable, and minimally invasive method to design operations. The technique can be an option for multilevel OLF surgical treatment. This can provide sufficient decompression with minimum damage to the spine and other intact anatomical structures.

Reliability analysis of Cobb measurement in degenerative lumbar scoliosis using endplate versus pedicle as bony landmarks.

OBJECTIVES: Degenerative changes of endplates in older patients and tilting of vertebral body in lumbosacral lordosis could make an accurate identification of endplates for the Cobb measurement difficult. Pedicles have been proposed as alternative landmarks because they are usually better visualized, and offer similar clinical validity to the endplates. The objective of this study was to investigate the reliability of the pedicle method of Cobb measurement in degenerative lumbar scoliosis and compare it with the traditional endplate method. METHODS: Two hundred and eighty-four radiographs of degenerative lumbar scoliosis were evaluated. The radiographs were classified into groups based on the patient's age (< 60 years, 60 to 80 years, and > 80 years), level of lower end vertebra (LEV) (LEV at L5, and LEV at or above L4), and curve severity (< 20°, 20° to 40°, and > 40°). Three observers independently measured the radiographs using the endplate and pedicle methods twice with an interval of 1 week. The intra- and interobserver reliabilities were calculated using intraclass correlation coefficients (ICC). RESULTS: The intra- and interobserver ICC values were better for all observers in the > 80 years age group using the pedicle method. The intraobserver ICC values of pedicle method were also better in the LEV at L5 group, and the interobserver ICC values showed a slightly better consistency with the pedicle method. For patients with > 40° curves, the intraobserver ICC values for all observers as well as interobserver ICC values were better using the endplate method. CONCLUSION: The reliabilities of the endplate and pedicle methods for degenerative lumbar scoliosis were both excellent. The pedicle method might be better in older patients (> 80 years) and those with LEV at L5; while the endplate method could have some strength in severe cases (> 40°).

Does a deep seated L5 vertebra position with respect to the iliac crests affect the accuracy of percutaneous pedicle screw placement at lumbosacral junction?

BACKGROUND: Significant prominence of iliac crests with a deep seated L5 vertebra can potentially interfere with the screw trajectory when placing percutaneous pedicle screws (PPS) at the lumbosacral segment. The objective of this study was to investigate the influence of L5 position in relation to the iliac crests on the accuracy of percutaneous placement of lumbosacral pedicle screws. METHODS: From Oct 2012 to Sep 2014, 54 patients who underwent PPS placement at L5-S1 segment were recruited. Patients were divided into 2 groups: the L5-Seated Group (L5-S Group, n = 34) including patients with intercrest lines passing through the L4 vertebra or L4/5 intervertebral disc; whereas the L5-Non-Seated Group (L5-NS Group, n = 20) including patients with intercrest lines passing through the L5 vertebra. Postoperative computerized tomography was obtained in all patients, and PPS accuracy was evaluated by grading pedicle breach (Grade 0, no breach; Grade 1, ≤2mm; Grade 2, >2mm without neurological compromise; Grade 3, with complications). Screw convergence angle (SCA), defined as the angle subtended by the screw axis and vertebral midline, was also recorded. RESULTS: In the L5-S Group, 82.4% (56/68) screws were measured as Grade 0 at L5, and 66.2% (45/68) were Grade 0 at S1; meanwhile, in the L5-NS Group, 77.5% (31/40) and 75.0% (30/40) screws were Grade 0 at L5 and S1, respectively. Misplacement rate was numerically higher at S1 in the L5-S Group (P > 0.05). There were significantly more medial pedicle violations at S1 in the L5-S Group as compared to the L5-NS Group (25.0% vs 7.5%, P = 0.024). No statistical difference was found in L5 SCA between the 2 groups (L5-S Group 23.7° ± 7.4° vs L5-NS Group 23.4° ± 10.6°, P = 0.945); however, S1 SCA was significantly smaller in the L5-S Group (14.7° ± 5.8°) when compared with the L5-NS Group (20.8° ± 5.2°) (P = 0.036). CONCLUSIONS: A deep seated L5 vertebra with respect to the iliac crests might compromise the accuracy of PPS placement at S1 vertebra. Severe iliac prominence may interfere with the screw trajectory and limit the medial angulation of pedicle screw for percutaneous S1 fixation.

Application of a narrow-surface cage in full endoscopic minimally invasive transforaminal lumbar interbody fusion.

BACKGROUND: Spinal endoscopy has been widely applied in lumbar discectomy and decompression. However, endoscopic lumbar interbody fusion still remains a technical challenge due to the limited space within the working trocar for cage implantation. The purpose of this study was to investigate the feasibility and effectiveness of using a narrow-surface fusion cage in full endoscopic minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for the treatment of lumbar degenerative disease. MATERIALS AND METHODS: From Jun 2013 to Dec 2014, a total of 42 patients (23 males, 19 females) underwent full endoscopic MIS-TLIF at our hospital was recruited. An 8-mm-wide narrow-surface fusion cage was selected for all cases. Perioperative parameters and complications were recorded. Comparisons on visual analog scale (VAS) and oswestry disability index (ODI) scores before and after surgery were performed. At the last follow-up, Nakai grading system was applied to assess patients' satisfaction; meanwhile, interbody fusion was evaluated by computed tomography. RESULTS: Mean operation time was 233.1 ± 69.5 min, and mean blood loss during surgery was 221.8 ± 98.5 ml. Two patients (4.8%) developed neurological complications. Postoperative follow-up ranged from 24 to 36 months (mean 27.6 ± 3.8 months). VAS and ODI scores were significantly improved 3 months after surgery and at the final follow-up, respectively (P < 0.05). Outcome of surgery was graded as excellent for 32 patients, good for 8 patients, and acceptable for 2 patients, corresponding to a success rate ("good" and "excellent") of 95.2%. Thirty-nine of the 42 patients demonstrated solid interbody fusion at the last follow-up, indicating a fusion rate of 92.9%. CONCLUSION: Application of a narrow-surface fusion cage in full endoscopic MIS-TLIF for the treatment of lumbar degenerative disease is feasible and effective. The clinical outcome and fusion success of this procedure were acceptable and promising.

Large enchondroma of the thoracic spine: a rare case report and review of the literature.

BACKGROUND: Enchondroma, a subtype of chondroma, originates from the medullary cavity of the bone and produces an expansile growth pattern. Enchondroma located in the spine is rare and a few cases of large thoracic enchondroma have been reported. The authors document a rare case of large enchondroma in the thoracic spine of a 49-year-old woman, and discuss its clinical, radiological and histopathological characteristics. CASE PRESENTATION: The patient presented with rapidly progressive and severe pain on her upper back. Magnetic resonance imaging revealed an expansile lesion at the posterior elements of T3 that was hypointense on T1-weighted images and mixed iso- to hyperintense on T2-weighted images. Administration of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) resulted in heterogeneous enhancement. During surgery, a large tumor of 4.2cm × 4.7cm × 2.1cm was resected along with the lamina and spinous process. Histological examination revealed that the tumor consisted of mature hyaline cartilage with typical chondrocytes, indicating that it was an enchondroma. CONCLUSIONS: Despite its benign-growing nature, enchondroma should be examined closely for signs of enchondromatosis and enchondrosarcoma. Complete surgical resection is the treatment of choice for immediate relief of symptoms and avoidance of recurrence.

Up-regulation of microRNA-491-5p suppresses cell proliferation and promotes apoptosis by targeting FOXP4 in human osteosarcoma.

BACKGROUND AND OBJECTIVES: MicroRNAs are small non-coding RNAs involved in pathogenesis and progression of human malignancies. MicroRNA-491-5p (miR-491-5p) is down-regulated in many human cancers where it would serve as a tumour suppressor. However, the role played by miR-491-5p in pathogenesis of human osteosarcoma has remained largely unknown. This study has been conducted to examine effects of miR-491-5p on migration and proliferation of cells of the SAOS-2 and MG63 osteosarcoma lines, and mechanisms of those effects. MATERIALS AND METHODS: Levels of miR-491-5p expression in osteosarcoma tissues and in human osteosarcoma cell lines were studied using qualitative real-time polymerase chain reaction (qRT-PCR) methods. Cell viability was detected using the CCK-8 and EdU assays, while the transwell assay was used to evaluate migration and invasion. Apoptosis was analysed uing flow cytometry and the Hoechst 33342 nuclear staining method. A dual-luciferase reporter system was used to confirm the target gene of miR-491-5p. The electrophoretic mobility shift assay (EMSA) with DIG-labelled double-stranded FOXP4 oligonucleotides was used to confirm whether or not miR-491-5p suppressed FOXP4 activation. RESULTS: Cells of osteosarcoma tissues and cell lines had low levels of miR-491-5p expression, but high levels of forkhead-box P4 (FOXP4) expression. Transfection of SAOS-2 and MG63 cells with miR-491-5p mimics inhibited expression of FOXP4 protein, which suppressed cell growth and migration, but induced apoptosis. Dual-luciferase reporter assays confirmed FOXP4 as the target gene for miR-491-5p. Overexpression of miR-491-5p suppressed FOXP4 activity in SAOS-2 and MG63 cells. Knockdown of FOXP4 in SAOS-2 and MG63 cells using an RNAi strategy resulted in reduced levels of cell proliferation and migration, but increased levels of apoptosis. CONCLUSION: Our in vitro studies showed that up-regulation of miR-491-5p suppressed proliferation of the human osteosarcoma cells and induced apoptosis by targeting FOXP4. These findings suggest that miR-491-5p could be further studied as a potential clinical diagnostic or predictive biomarker for human osteosarcoma.

Brucella infection of the thoracic vertebral arch presenting with an epidural abscess: a case report.

INTRODUCTION: Although Brucella spondylitis and Brucella discitis have been frequently reported, Brucella infection of the vertebral arch is rare and has not been previously described. We present the first case of Brucella infection of the thoracic vertebral arch with epidural abscess formation and discuss the clinical key points. CASE PRESENTATION: A 57-year-old man of Han nationality with a history of contact with an isolated sheep stomach 2 months previously was admitted with an undulant fever, night sweats, back pain, and weakness. Thoracic magnetic resonance imaging showed laminar destruction of T9 and an epidural abscess at the T9 to 10 level with significant cord compression. Diagnosis of Brucella infection of his vertebral arch was confirmed by a positive blood culture with growth of Brucella melitensis. Total laminectomy, abscess cleansing, and percutaneous pedicular screw fixation was performed initially, followed by antibiotic treatment with a combination of doxycycline and rifampin for 4 months. Recovery was confirmed by clinical, magnetic resonance imaging, and blood culture findings. CONCLUSIONS: This is an unusual case of Brucella infection of the vertebral arch with epidural abscess formation. Effective antibiotic therapy of a sufficient duration and timely performance of surgical treatment are the key points in management of such cases.

A minimally invasive posterior lumbar interbody fusion using percutaneous long arm pedicle screw system for degenerative lumbar disease.

The aim of this study is to evaluate the therapeutic efficacy of patients with lumbar degeneration and instability treated with percutaneous pedicle screw fixation and minimally invasive lumbar interbody fusion. Twenty-one patients were selected in our hospital from November, 2012 to March, 2013. The patients with an average age 55.62 years, including 8 vertebral spondylolisthesis, 4 lumbar intervertebral disc herniation, and 9 lumbar spinal canal stenosis cases. All the patients were managed to take the lumbar MRI and radiographs. The comparison of preoperative and postoperative (3 days, 2 weeks, 3 months) VAS and ODI score were analyzed. The results indicated that VAS scores were 7.14 ± 0.79 before operation, and 5.19 ± 0.81 in 3 days after operation, 4 ± 0.84 after 2 weeks, and 2.67 ± 0.66 after 3 months. The pain was relieved, and the postoperative VAS score was lower than that before treatment (P < 0.05). ODI score was 55.8 ± 11.4 before operation, 47.38 ± 9.38 after 3 days, 41.38 ± 8.09 after 2 weeks, 35.76 ± 4.50 after 3 months. ODI score was obviously decreased (P < 0.05). In conclusion, percutaneous pedicle screw fixation combined with minimally invasive interbody fusion is a safe, effective, feasible minimally invasive spine operation, with worthy for spreading.