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.

Overexpression of long non-coding RNA MFI2 promotes cell proliferation and suppresses apoptosis in human osteosarcoma.

The long non-coding RNA MFI2 antisense RNA is overexpressed in human cancer tissues and its increased expression is associated with occurrence and metastasis of cancer. However, the underlying mechanism in evolution and progression of human osteosarcoma is not well known. In the present study, we aimed to evaluate the molecular mechanism of lncRNA MFI2 in promoting osteosarcoma cell proliferation and suppressing apoptosis. We found that the lncRNA MFI2 was significantly overexpressed in human osteosarcoma tissues. Knockdown of lncRNA MFI2 expression suppressed MG63 and SAOS-2 cell proliferation, migration and invasion, and induced cell apoptosis. Furthermore, the expression of forkhead box P4 (FOXP4) was significantly increased and it was positively associated with lncRNA MFI2 expression in tumor tissues. In addition, knockdown of FOXP4 expression by RNA interference strategy inhibited osteosarcoma cell proliferation, migration and invasion, and promoted cell apoptosis. All the results indicated lncRNA MFI2 could promote proliferation and migration of osteosarcoma cells by regulating FOXP4 expression, which suggested critical roles of lncRNA MFI2 and FOXP4 in occurrence and development of 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.

Three-dimensional visualization of the cutaneous angiosome using angiography.

The purpose of this study was to establish the three-dimensional (3D) architecture of the cutaneous angiosome for assessment and design of the perforator flaps. Two fresh cadavers were injected with carboxymethyl cellulose (CMC)/lead oxide and computed tomography (CT) scanned before and after the injection. The various parts of the cutaneous and subcutaneous tissue derived from one of the injected cadavers were also CT scanned. Three-dimensional reconstruction of the cutaneous angiosome and the two flap designs were performed using Materialise's Interactive Medical Image Control System (MIMICS). Both the reconstructed cutaneous angiosomes and the digital flaps can be displayed independently or in conjunction with bones, source arteries, and skin. The 3D architecture of the cutaneous angiosome ensures clear display of the spatial location, distribution range, and anastomoses relationship of the cutaneous perforators. In addition, the caliber, length, and position of a particular source artery are illustrated in the exact spatial location. As a result, the technique provides visualization of the general area and the expandable direction of a respective flap. This technique has the potential to play an important role in assessing perforator blood supply territory and in the design of new flaps.

A mini pig model for visualization of perforator flap by using angiography and MIMICS.

BACKGROUND: Research performed using animal models has assisted in the understanding of flap anatomy and physiology. Pigs' vasculature in the skin is anatomically and physiologically similar to human, making it an ideal model for research. Until now, most vascular imaging studies are of two-dimensions. The aim of this study is to provide a three-dimensional (3D) model that reveals detailed architecture of the vascular network of the porcine, for accurate quantitative assessment. METHODS: Five Guangxi Bama minipigs were anaesthetized intramuscularly and underwent whole body lead oxide-gelatin injection. Spiral computed tomography scanning was performed on the subjects and three-dimensional reconstructions were made. Another minipig was used, and underwent Cardiografin injection. 3D-reconstruction was executed in vivo. All subjects were then dissected by layers to document the individual perforators. RESULTS: Angiography using perfusion with lead oxide-gelatine mixture has the advantage of illustrating distinctively the vessels and their perforating branches. However, it is incapable of displaying other tissues structures. Angiography through perfusion with Cardiografin in vivo has the advantage of demonstrating the relationship between arteries and bones. Yet it could only display coarsely the vascular trunk, and is incapable of displaying the vascular network. By combining these two methods, the 3D structure, source, course, and territories of the arteries were presented distinctively. CONCLUSIONS: 3D modeling in combination with traditional sectional imaging of the pig model enables blood vessels to be displayed more dynamically with greater realism. The procedure described could be useful for future flap research, by offering a better visualization of the vascular structure of the skin flap, allowing for better anatomical understanding.

[Modification of a percutaneous transpedical interbody bone grafting apparatus and its application in cadaveric operation].

OBJECTIVE: To modify a percutaneous transpedical interbody bone grafting apparatus for better surgical performance in transpedical interbody bone grafting. METHODS: The puncture needle, guide pin and expander were removed from the original design of interbody bone grafting apparatus, with also modification of the bone grafting funnel, obturator, wick and bone harvesting device. Percutaneous puncture and transpedical interbody bone grafting were performed using the modified apparatus on two cadavers, and the operative procedures, bone grafting scope and surgical trauma were observed. RESULTS: This modified apparatus allowed increased bone grafting scope with shortened operative time, simplified operation procedures, and reduced surgical trauma. CONCLUSION: Percutaneous puncture and transpedical interbody bone grafting can be easily and safely performed with the modified apparatus.

Histological changes of an injectable rhBMP-2/calcium phosphate cement in vertebroplasty of rhesus monkey.

STUDY DESIGN: A histologic study of recombinant human bone morphogenetic protein-2/calcium phosphate cement (rhBMP-2/CPC) using adult rhesus monkeys in vivo. OBJECTIVE: To evaluate the histologic changes of rhBMP-2/CPC in vertebroplasty and determine the feasibility of this bone substitution instead of polymethylmethacrylate (PMMA). SUMMARY OF BACKGROUND DATA: Previous studies have shown that the new rhBMP-2/nanoscale CPC has a suitable strength and injection for vertebroplasty. However, the osteoinductive properties and biodegradable characteristics are still unclear. METHODS: Percutaneous vertebroplasty (PVP) was performed in 4 adult rhesus monkeys of 2 groups. Ten vertebral bodies (VBs) from T10-L7 of each rhesus were selected, and the 20 VBs in each group were randomly divided into 3 subgroups. Subgroup A (rhBMP-2/CPC): 8 VBs, filled with rhBMP-2/CPC; Subgroup B (PMMA): 6 VBs, filled with injectable PMMA; Subgroup C (control): 6 VBs, filled with normal saline. The 2 rhesus monkeys from each of the groups were killed at 2 and 6 months after operation, respectively. Individual specimens from the 40 VBs were collected for histologic observation. RESULTS: In subgroup A, radiographic and histologic observations showed that the part of the rhBMP-2/CPC cement degraded with new bone and new vessel ingrowths, into the material, after 2 months. In addition, gaps, fibrous hyperplasia, or sclerotic callus were not found in the interface. After 6 months, the cement was nearly all replaced by mature bone tissue. In subgroup B, the inflammatory cell infiltration and fibrous membrane gapping were found after 2 months, and subsided partly at 6 months. But no new bone formation and material degradation were discovered. In subgroup C, the tunnels were filled with irregular new trabeculae after 2 months and unrecognizable from the surrounding mature bone after 6 months. CONCLUSION: It is confirmed that the rhBMP-2/CPC is an osteoinductive and biodegradable material (in animal trials). It may also be an alternative to PMMA in order to achieve biostabilization in a vertebroplasty.

A pilot study on three-dimensional visualization of perforator flaps by using angiography in cadavers.

BACKGROUND: Perforator flaps have become popular worldwide, in part because of their ability to reliably support a large skin territory on a single perforator. Although the lead oxide injection technique provides excellent images for anatomical study, it is not possible to show the location, course, and direction of the source artery. Materialise's Interactive Medical Image Control System allows microvascular anatomy to be evaluated in three-dimensions to design perforator flaps. METHODS: Two fresh cadavers were injected using the lead oxide-gelatin injection technique. The cadavers were imaged using a spiral computed tomography scanner. The computed tomographic data were transferred to Digital Imaging and Communications in Medicine format and imported to a personal computer. Three-dimensional reconstructions of various parts of the body were then performed using Materialise's Interactive Medical Image Control System software. RESULTS: : Three-dimensional visualization of various parts of the body was obtained. This technique clearly shows the bone, soft tissue, skin, and vascular structures in a layer-by-layer transparent process. The detailed views of the microvasculature provide extensive information regarding the course of vessels in all layers of tissue. CONCLUSIONS: The intricate vascular details captured by this technique clearly demonstrate the three-dimensional anatomy of the integument, bone, and soft tissue in a layer-by-layer transparent process. It is a powerful, quick, easy method with which to demonstrate cadaver vascular anatomy that may be useful in the design of surgical flaps.

Three-dimensional visualization of pelvic vascularity.

The aim of this study was to establish a 3D digitized model of pelvic vasculature for anatomic study, preoperative planning, and virtual reality. Three adult fresh cadavers were perfused with carboxymethyl cellulose/lead oxide mixture to mark blood vessels, and subjected to multilayer spiral computed tomography scanning to obtain a series of thin sections. Then, the 2D images of the pelvis and pelvic blood vessels were transformed into 3D digitized models using Mimics 11.0. The 2D images of carboxymethyl cellulose/lead oxide filled arteries had the features of entire outline and few constructed defects. The 3D digitized models of the pelvis and pelvic artery system displayed spatial location and the adjacent relationship of arteries with the pelvis. Not only the well-known arteries but also the tiny blood vessels in the reconstructed structures were well demonstrated and observed interactively. The reconstructed tissue flaps, including a lobulated skin flap with the pedicle of superficial epigastric artery, and an iliac flap with the pedicle of deep iliac circumflex artery, demonstrated their blood supply area. This indicated that the modified technique of vascular perfusion with carboxymethyl cellulose/lead oxide and reconstitution with Mimics 11.0 software contributed to 3D digitized model of pelvic vasculature.

[Surgery simulation with a percutaneous and transpedical interbody bone grafting apparatus].

OBJECTIVE: To develop a percutaneous and transpedical interbody bone grafting apparatus for vertebral bone defect reconstruction in thoracolumbar fracture correction via minimally invasive operation. METHODS: The percutaneous and transpedical interbody bone grafting apparatus was designed with CAD software, and the reduction effect, range of bone grafting and surgical complications of the apparatus were investigated in adult cadaveric thoracolumbar body and with computerized surgical simulation. RESULTS: The self-designed apparatus was convenient for percutaneous and transpedical interbody bone grafting that did not give rise to complications. CT showed large bone grafting area with increased density in the vertebral body corrected with this apparatus. CONCLUSION: The designed apparatus allows easy manipulation and efficient bone grafting and repositioning. Minimally invasive interbody bone grafting in thoracolumbar fracture can be easily performed with proper application of the apparatus.