Percutaneous Robot-Assisted versus Freehand S2 Iliosacral Screw Fixation in Unstable Posterior Pelvic Ring Fracture.

OBJECTIVES: To assess the efficiency, safety, and accuracy of S2 (IS) screw fixation using a robot-assisted method compared with a freehand method. METHODS: This is a retrospective clinical study. We analyzed the patients treated with S2 IS screw fixation for unstable pelvic fractures from January 2016 to January 2019 in our institution. Sixty-three patients (17 men and 46 women) aged between 21 and 55 years (with an average age of 39.22 ± 9.28) were included in this study. According to the Tile classification, there were 26 (41.3%) type B fractures and 37 (58.7%) type C fractures. All patients were divided into robot-assisted (RA) group (38 patients) or the traditional freehand (FH) group (25 patients). In RA group, the S2 IS screws were implanted with a robot-assisted technique. And S2 IS screws were implanted with a traditional freehand technique in FH group. The screw-related complications were recorded during and after the surgery. The position of all screws and fracture reduction was assessed by postoperative CT scans according to the Gras classification. The number of guide wire attempts and the radiation exposure for S2 screw implantation during operation were also recorded. Finally, the Matta standard was used to evaluate the fracture reduction of the IS joint. RESULTS: A total of 89 IS screws were implanted into S2 iliosacral joint. Fifty-four screws were placed by RA (38 patients) and 35 screws were by FH (25 patients). There was no difference between the two groups with respect to demographic data. There was no screw-related complications or revision surgery in any group. In terms of screw placement, the excellent and good rate was 100% in the RA group, better than that in the FH group where it was only 85.7% (P < 0.001). The fluoroscopy time was 8.06 ± 3.54 s in RA group, which was much less than that in the FH group (27.37 ± 8.82 s, P < 0.001). The guide wire attempts in the RA group (0.685 ± 0.820) were much less than those in the FH group (5.77 ± 3.34) (P < 0.001). Both the fluoroscopy time per screw and the number of guide wire attempts in the RA group were much less than those in the FH group (P < 0.001). The overall postoperative excellent and good rate of Matta standard in RA and FH groups were 86.8% (34/4) and 90.0% (23/25), respectively (P = 0.750), and there was no statistical difference. CONCLUSION: The robot-assisted surgery is an accurate and minimally invasive technique. S2 IS screw implantation assisted by TiRobot to treat the posterior pelvic ring fractures, have a high success rate than the freehand technique. Percutaneous RA S2 IS screw fixation for unstable posterior pelvic ring injuries is safe and clinically feasible and has great clinical application value.

Effects of different 2A peptides on transgene expression mediated by tricistronic vectors in transfected CHO cells.

Multicistronic vectors can increase transgene expression and decrease the imbalance of gene expression in the Chinese hamster ovary (CHO) cell expression system. Small, self-cleaving 2A peptides have a high cleavage efficiency and are essential for constructing high-expression multicistronic vectors. In this study, we investigated the effects of two different 2A peptides on transgene expression in CHO cells via their mediating action on tricistronic vectors. The enhanced green fluorescent protein (eGFP) and red fluorescent protein (RFP) genes were linked by the porcine teschovirus-1 (P2A) and Thosea asigna virus (T2A) peptides in a multicistronic vector. We transfected CHO cells with these vectors and screened for the presence of blasticidin-resistant colonies. Flow cytometry and real-time quantitative PCR (qPCR) were used to detect the expression levels of eGFP and RFP and the copy numbers of stably transfected cells. The results showed that P2A could enhance eGFP and RFP expression by 1.48- and 1.47-fold, respectively, compared to T2A. The expression levels of the genes were not proportional to their copy numbers. In conclusion, we found that P2A can effectively drive transgene expression in CHO cells and a potent 2A peptide can be used for recombinant protein production in the CHO cell system.

Guidance for Treatment of Pelvic Acetabular Injuries with Precise Minimally Invasive Internal Fixation Based on the Orthopaedic Surgery Robot Positioning System.

Pelvic acetabular fracture is a common kind of fracture, mostly caused by high energy injuries. It is associated with high mortality and disability rates. The aim of surgical treatment of pelvic acetabular fractures is to restore the symmetry and stability of the pelvic ring structure and the anatomical structure of acetabular. Open reduction internal fixation is often used for the treatment of such fractures, but open surgery is in cases of serious injury, more bleeding, and high risk of infection. With the development of minimally invasive technology and the concept of the bone channel structure, the percutaneous lag screw technique for the treatment of pelvic and acetabular fractures has been applied in clinical practice and has proven to be effective. However, the anatomical structure of the pelvis and acetabulum is complex, and there are many important nerves and vessels adjacent to it. Traditional fluoroscopy screw placement is prone to screw malposition, and even minor angle changes may lead to screw perforation and damage of nerve vessels. The problem of radiation exposure is also noteworthy. Robotic-assisted surgery can be used to carry out screw position planning through preoperative imaging, intraoperative real-time tracking, and mechanical arm assistance to ensure that the screw placement position is consistent with the planning. In this way, robotic-assisted surgery can be used to accurately insert lag screws, and can reduce surgical risk and radiation exposure. This guide uses the TiRobot system as an example to describe the application of robot surgery in detail, aiming at standardizing the application of robots in orthopaedic surgery.

Evaluation of a Bi-Planar Robot Navigation System for Insertion of Cannulated Screws in Femoral Neck Fractures.

OBJECTIVE: To evaluate the bi-planar robot navigation system for insertion of cannulated screws in femoral neck fractures. METHOD: Between January 2016 and December 2016, 60 patients with femoral neck fractures were separately treated using percutaneous cannulated screws assisted by the bi-planar robot navigation system (robot group) and conventional freehand surgery (freehand group). The fluoroscopy time, the number of drilling attempts, and the operation time were recorded during operations; the dispersion and parallelism of the cannulated screws on the posteroanterior and lateral images were measured after operations. Patients were followed up for 12-24 months and the Harris scores and the final results of the two groups were compared. RESULTS: During bi-planar robot navigation system-assisted surgery, the fluoroscopy time for acquisition of images was 2.3 seconds on average, and the time for planning screws during the operation was 2.8 min on average. The average fluoroscopy time during the placement of the guide pin was 5.7 seconds and 14.14 seconds (P = 0.00), respectively. The average time of the placement of the cannulated screws was 12.7 min and 19.4 min (P = 0.00), respectively, in the robot group and the freehand group. In the robot group, only one guide pin was replaced during the operation, and the average number of adjustments for each guide pin was 2.39 in the freehand group. The screw parallelism and dispersion measured by postoperative imaging in the robot group were significantly superior to those in the freehand group. From postoperative CT it was evident that there were 5 cases of screws exiting the posterior cortex in both groups. During the follow-up phase, 1 case of femoral head necrosis and 5 cases of femoral neck shortening of more than 10 mm occurred in the robotic navigation group; 3 cases of femoral head necrosis, 1 case of fracture nonunion, and 2 cases of shortening of more than 10 mm occurred in the freehand group. At 18 months after surgery, the average Harris scores of the patients were 85.20 and 83.45, respectively, with no significant difference. CONCLUSION: Using bi-planar robot navigation system-assisted placement of femoral neck cannulated screws can significantly reduce the time of intraoperative fluoroscopy, drilling attempts, and operation time. The placed screws are superior to the screws placed freehand in relation to parallelism and dispersion. However, it is still necessary for surgeons to have a good reduction of the femoral neck fracture before surgery and to be proficient in the operation of the robot navigation system. In summary, the bi-planar robot navigation system is an effective assistant instrument for surgery.

[Effects of Different Promoters and MAR Combinations on Transgene Expression of Recombinant CHO Cells].

OBJECTIVE: To analyze the effects of different promoters and matrix attachment region (MAR) on the expression of transgene in Chinese hamster ovary (CHO) cells. METHODS: The expression vector was constructed by the combination of beta globin MAR (gMAR) with the human cytomegalovirus immediate-early promoter (CMV-IE) and simian virus 40 (SV40) promoter. These vectors were transfected into CHO cells,after 48 h,the transient expression of enhanced green fluorescent protein (eGFP) was observed; G418 was used to screen stably transformed cell lines,and the expression level of eGFP in CHO cells was analyzed by flow cytometry. The relative copy numbers of eGFP were analyzed by qPCR. RESULTS: Without gMAR expression vector,the expression of eGFP which was driven by CMV-IE promoter was stronger than that of SV40 promoter; gMAR could increase the expression level of eGFP driven by CMV-IE promoter,but did not show any enhancement in SV40 promoter. The expression level of eGFP which containing gMAR on both sides was stronger than that of gMAR on one side driven by CMV-IE promoter; After G418 screening,the expression level of eGFP containing gMAR driven by SV40 promoter wasunstable,the fluorescence gradually weakened,therefore,we only analyzed the expression vector stably expressing the eGFP gene driven by CMV-IE promoter by flow cytometry and qPCR. Compared with the expression vector without gMAR containing CMV-IE promoter,flow cytometry showed that the expression levels of eGFP on one and both sides with gMAR were increased by 9.85-fold and 12.94-fold,respectivley; The result of qPCR showed that the copy number of the eGFP gene without gMAR was set to 1,the copy number of the eGFP gene in the expression vector driven by CMV-IE with gMAR on one side and both sides were 3.68-fold and 9.25-fold,respectively. CONCLUSION: The activity of CMV-IE promoter is stronger than that of SV40 promoter. gMAR can enhance the expression levels of transgene,which may be related to the increase of gene copy number.

Overexpression of suppressor of IKBKE 1 is associated with vincristine resistance in colon cancer cells.

In a previous study, the suppressor of IKBKE 1 expression level was confirmed to be higher in vincristine (VCR)-resistant HCT-8 (HCT-8/V) colon cancer cells than in non-VCR-resistant HCT-8 cells. In the current study, IKBKE 1 expression in VCR-resistant colon cancer cells was investigated further. HCT-8 and HCT-8/V human colon cancer cells were used, and polymerase chain reaction (PCR) primers were designed to amplify the IKBKE 1 gene. Fluorescence reverse transcription-quantitative PCR (RT-qPCR) was performed to detect differences in IKBKE 1 expression between sensitive and drug-resistant colon cancer cell lines. Western blotting was performed to further observe IKBKE 1 expression. Based on the RT-qPCR and western blot results, IKBKE 1 expression was observed to be markedly higher in the HCT-8/V cells, and this difference was significant (P<0.05). Thus, IKBKE 1 expression was identified to be associated with the resistance of colon cancer cells to VCR.

Impact of Different Promoters on Episomal Vectors Harbouring Characteristic Motifs of Matrix Attachment Regions.

We previously demonstrated that the characteristic sequence of matrix attachment regions (MARs) allows transgenes to be maintained episomally in CHO cells. In the present study, six commonly used promoters from human cytomegalovirus major immediate-early (CMV), simian vacuolating virus 40 (SV40), Rous sarcoma virus, Homo sapiens ubiquitin C, phosphoglycerate kinase, and ß-globin, respectively, were evaluated to determine their effects on transgene expression and stability in CHO cells stably transfected via the episomal vector harbouring characteristic MAR motifs. The CHO cells were transfected with vectors and then screened using G418, after which the stably transfected cells were split into two and further cultured either in the presence or absence of G418. Of the six promoters, the CMV promoter yielded the highest transgene expression levels and the highest transfection efficiency, whereas the SV40 promoter maintained transgene expression more stably during long-term culture than the other promoters did. The CMV and SV40 promoter-containing vectors were furthermore episomally maintained and conferred sustained eGFP expression in the cells even under nonselective conditions. On the basis of these findings, we conclude that the CMV promoter performs best in terms of yielding both high expression levels and high levels of stability using this episomal vector system.

Treating Colon Cancer Cells with FK228 Reveals a Link between Histone Lysine Acetylation and Extensive Changes in the Cellular Proteome.

The therapeutic value of FK228 as a cancer treatment option is well known, and various types of cancer have been shown to respond to this drug. However, the complete mechanism of FK228 and the affect it has on histone lysine acetylation and the colon cancer cell proteome are largely unknown. In the present study, we used stable isotope labeling by amino acids in cell culture (SILAC) and affinity enrichment followed by high-resolution liquid chromatograph-mass spectrometer (LC-MS)/MS analysis to quantitate the changes in the lysine acetylome in HCT-8 cells after FK228 treatment. A total of 1,194 lysine acetylation sites in 751 proteins were quantified, with 115 of the sites in 85 proteins being significantly upregulated and 38 of the sites in 32 proteins being significantly downregulated in response to FK228 treatment. Interestingly, 47 histone lysine acetylation sites were identified in the core histone proteins. We also found a novel lysine acetylation site on H2BK121. These significantly altered proteins are involved in multiple biological functions as well as a myriad of metabolic and enzyme-regulated pathways. Taken together, the link between FK228 function and the downstream changes in the HCT-8 cell proteome observed in response to FK228 treatment is established.

Expression profile analysis of long non-coding RNA associated with vincristine resistance in colon cancer cells by next-generation sequencing.

Vincristine (VCR) is widely used in tumor treatment. However, long-term use of this drug can make tumor cells resistant to it. Furthermore, the mechanisms underlying resistance development are unclear. The aim of this study was to investigate the long non-coding RNAs (lncRNAs) associated with colon cancer drug resistance using next-generation sequencing. A cDNA library of HCT-8 VCR-resistant colon cancer cell was established through PCR amplification. Using HiSeq 2500 sequencing and bioinformatic methods, we identified lncRNAs showing different expression levels in drug-resistant and non-resistant cells, and constructed expression profiles of the lncRNA differences. The pretreatment of data was quality controlled using FastQC software. Transcription of lncRNA was calculated using Fragments Per Kilobase of transcript per Million fragments mapped (FPKM). To reveal the potential functions of these lncRNAs, we applied GO analysis to study the differentially expressed lncRNAs. Total transcript number was higher in resistant cells than in non-resistant colon cancer cells, and high-quality transcripts constituted the major portion of the total. In addition, 121 transcripts showed significantly different expression in VCR-resistant and non-resistant cells. Of these, we observed 23 up-regulated and 20 down-regulated lncRNAs (fold change >10.0). This is the first report of the expression profile of lncRNA of VCR-resistant colon cancer cells. Abnormal lncRNA expression was associated with VCR resistance in colon cancer cells and these expression differences may play a key role in VCR resistance of these cells.

The effect of recombinant lentiviral vector encoding miR-145 on human esophageal cancer cells.

miR-145, a newly identified microRNA molecule, is hypothesized to function as a tumor suppressor, but this activity has not been investigated in esophageal l carcinoma (EC). The aim of this study was to investigate the effect of miR-145 on the biological features of EC cells. miR-145 was obtained using PCR technology and cloned into the lentiviral vector, pLVX-IRES-ZsGreen1, to construct the resulting vector, pLVX-IZ-miR-145. The vector was packaged, the viral titer was tested, and ECA109 cells were infected with the optimal viral titer. Cells that were stably transfected with miR-145 were screened. Flow cytometry was used to analyze enhanced green fluorescence protein gene expression, and to measure cell apoptosis and cell cycle. miR-145 expression was detected by real-time fluorescent quantitative PCR. Furthermore, cell proliferation was assayed using CCK-8 assay. The pLVX-IZ-miR-145 vector was successfully constructed, and the viral titer achieved up to 5.0 × 10(8) TU/mL. The transfection efficiency was 90 %. Compared to the control group, the expression level of miR-145 in the transfected group was significantly higher (185-fold, P < 0.05). miR-145 overexpression significantly inhibited esophageal cancer cell proliferation (P < 0.05). Moreover, the number of cells at the G2/M stage, as well as the cell apoptotic rate, in the miR-145-transfected group was significantly increased (P < 0.05). Our study reveals that overexpression of miR-145 inhibits cell proliferation, increases apoptosis, and influences the cell cycle progression of EC cell.

Printed three-dimensional anatomic templates for virtual preoperative planning before reconstruction of old pelvic injuries: initial results.

BACKGROUND: Old pelvis fractures are among the most challenging fractures to treat because of their complex anatomy, difficult-to-access surgical sites, and the relatively low incidence of such cases. Proper evaluation and surgical planning are necessary to achieve the pelvic ring symmetry and stable fixation of the fracture. The goal of this study was to assess the use of three-dimensional (3D) printing techniques for surgical management of old pelvic fractures. METHODS: First, 16 dried human cadaveric pelvises were used to confirm the anatomical accuracy of the 3D models printed based on radiographic data. Next, nine clinical cases between January 2009 and April 2013 were used to evaluate the surgical reconstruction based on the 3D printed models. The pelvic injuries were all type C, and the average time from injury to reconstruction was 11 weeks (range: 8-17 weeks). The workflow consisted of: (1) Printing patient-specific bone models based on preoperative computed tomography (CT) scans, (2) virtual fracture reduction using the printed 3D anatomic template, (3) virtual fracture fixation using Kirschner wires, and (4) preoperatively measuring the osteotomy and implant position relative to landmarks using the virtually defined deformation. These models aided communication between surgical team members during the procedure. This technique was validated by comparing the preoperative planning to the intraoperative procedure. RESULTS: The accuracy of the 3D printed models was within specification. Production of a model from standard CT DICOM data took 7 hours (range: 6-9 hours). Preoperative planning using the 3D printed models was feasible in all cases. Good correlation was found between the preoperative planning and postoperative follow-up X-ray in all nine cases. The patients were followed for 3-29 months (median: 5 months). The fracture healing time was 9-17 weeks (mean: 10 weeks). No delayed incision healing, wound infection, or nonunions occurred. The results were excellent in two cases, good in five, and poor in two based on the Majeed score. CONCLUSIONS: The 3D printing planning technique for pelvic surgery was successfully integrated into a clinical workflow to improve patient-specific preoperative planning by providing a visual and haptic model of the injury and allowing patient-specific adaptation of each osteosynthesis implant to the virtually reduced pelvis.

[Percutaneous pelvic fracture stabilization using CT-based 3D navigation software combined with targeting mechanical arm: a cadaver model trial].

OBJECTIVES: To investigate a new targeting mechanical arm for CT-based navigated percutaneous fixation of pelvic fractures, and to evaluate the safety and efficiency of the procedures. METHODS: Using CT-based 3D navigation software combined with targeting mechanical arm, percutaneous insertion of pelvic models (3 dry human cadaver pelvic skeletons and 5 plastic Sybone pelvic models) were performed, 8 pelvic models allowed percutaneous cannulated screw insertion of both S-I joint (2 S-I screws placement for each side, total 32 screws in this experiment) and both superior ramus (1 ramus medullary screw placement for each side, total 16 screws in this experiment). Percutaneous insertion of pelvic models (4 dry human cadaver pelvic skeletons and 4 plastic Sybone pelvic models, 1 S-I screws and 1 ramus medullary scre placement for each side, 32 screws in this experiment) were performed using fluoro-navigation system (Stryker, USA). Time necessary for every screw insertion were recorded. Accuracy of screw placement was assessed using C-arm imaging and direct eyes inspecting. The time and accuracy of the two methods were compared. RESULTS: The time required for the CT-based 3D navigation procedure (3.6 ± 1.2) min was significantly less than using the targeting mechanical arm compared to drilling freehand with navigation (9.1 ± 0.8) min (t = 2.50, P < 0.01). There was no significant difference in accuracy between the two methods. CONCLUSION: CT-based 3D navigation software combined with targeting mechanical arm should be potential to apply percutaneous sacroiliac screwing for pelvic fractures with more accurate and more reliable.

Computer-assisted navigation systems for insertion of cannulated screws in femoral neck fractures: a comparison of bi-planar robot navigation with optoelectronic navigation in a Synbone hip model trial.

BACKGROUND: Computer-assisted procedures have recently been introduced for navigated femoral neck screw placement. Currently there is little information available regarding accuracy and efficiency of the different navigated procedures. The aim of this study was to compare two fluoroscopic navigation tracking technologies, a novel bi-planar robot navigation and standardized optoelectronic navigation, versus standard freehand fluoroscopic insertion in a Synbone hip model. METHODS: Eighteen fixed Synbone hip models were divided into 3 groups. C-arm navigated cannulated screws (AO-ASIF, diameter 7.3 mm) were inserted using freehand targeting (control group). A novel bi-planar robot system (TINAV, GD2000) and an optoelectronic system (Stryker OTS Navigation System) were used for the navigated procedures (robot group and optoelectronic group). Accuracy was measured using radiographic evaluation including the measurement of screw parallelism and decentralization, and joint penetration. To evaluate the efficiency, the number of guidewire passes, operative time and fluoroscopic images taken were noted. RESULTS: The two computer-assisted systems provided significantly improved accuracy compared to the freehand technique. Each of the parameters, including guidewire passes and number of fluoroscopy images, was significantly lower when using the computer-assisted systems than for freehand-unguided insertion (P <0.05), but operative time was significantly shorter when using freehand-unguided insertion than for the computer-assisted systems (P <0.05). Accuracy, operative time and number of fluoroscopy images taken were similar among the two navigated groups (P >0.05), but guidewire passes in the robot group were significantly less than in the optoelectronic group (P <0.05). CONCLUSIONS: Both bi-planar robot navigation and optoelectronic navigation were similarly accurate and have the potential to improve accuracy and reduce radiation for freehand fluoroscopic targeting for insertion of cannulated screws in femoral neck fractures. Guidewire passes in the robot group were significantly less than in the optoelectronic group. However, both navigated procedures were associated with time-consuming registration and high rates of failed matching procedures.

[Primary clinical application of traction reductor for lower limb fracture].

OBJECTIVE: To develop a traction reductor for the reduction of lower limb fractures during the minimally invasive surgery and explore its safety and efficacy. METHODS: From February 2007 to March 2009, closed or limited open reduction plus percutaneous plate and screw internal-fixation were conducted in 34 patients with fracture of distal femur and tibia metaphysic, among which there were 3 distal femoral fractures (2 33-B, 1 33-C), 14 proximal tibial fractures (9 41-A, 3 41-B, 2 41-C) and 17 distal tibial fractures (9 43-A, 5 43-B, 3 43-C, 2 Gustilo I a), according to the Association for Osteosynthesis-Orthopaedic Trauma Association (AO-OTA) classification. Besides, closed reduction plus interlocking intramedullary nailing on tibial shaft fracture were applied in 36 patients (7 42-A, 21 42-B, 8 42-C, 2 Gustilo I a). All the 70 patients, with an average age of 37.6 years (range: 17 to 63 years) and average time before surgery of 4.7 d (range: 0.7 to 12.0 d), underwent reduction by self-designed traction reductor for lower limb fracture in the surgery. The reduction duration and C-arm fluoroscopy time were recorded. Recovery of the force line of affected limbs after surgery was determined by whether the line from anterior superior iliac spine to the interdigit between the first and second toe-web passed the patella center. And the distance from bilateral anterior superior iliac spine to medial malleolus tip as well as the difference between lower limbs were recorded to determine the recovery of length after surgery. Meanwhile, the varus-valgus and anteroposterior angulations after reduction were measured by AP and lateral X-ray. RESULTS: The reduction duration was 12.7 min (range: 7 to 31 min); X-ray fluoroscopy time, 1.3 min (range: 0.4 to 3.0 min); length difference between both lower limbs (6.5 ± 1.1) mm; and axial alignment difference (7.0 ± 1.8) mm. The X-ray result showed that varus-valgus angle was (2.75 ± 0.16)°; and anteroposterior angulation (5.13 ± 0.51)°. CONCLUSION: The traction reductor for lower limb fracture could achieve satisfying fracture reduction in the minimally invasive surgery of distal femur, tibia metaphysic and tibial shaft fracture.

[Percutaneous screw fixation in treatment of fractures of acetabular columns using computer-assisted imaging navigation system: experiment with cadaver model].

OBJECTIVE: To establish a new imaging protocol to acquire the most appropriate fluoro-images for fluoro-navigated percutaneous fixation of acetabular fracture and to evaluate the safety and efficiency of the procedures. METHODS: Guide needles were inserted into the bilateral anterior and posterior columns of the acetabula of 4 dry human cadaver pelvic skeletons and 4 plastic pelvic models. Then the pelvis skeletons were fixed to imaging guided surgery mimic operation modules. Dynamic fluoroscopy was conducted with C-arm X-ray machine vertically on the 4 virtual planes of the acetabulum, inner, outer, anterior, and posterior from multiple angles. The fluoroscopic images clearly showing the guide needles, anterior and posterior columns, and acetabulum were selected as registration images, and the relative space positions between the C-arm X-ray fluoroscope and pelvis and operation table. Guided by the navigation system, totally 16 titanium hollow screws were inserted into bilateral anterior and posterior columns of acetabula of the 4 pelvis skeletons. The screw positions were estimated by visual method. The time needed to position the C-arm so as to obtain the standard registration image, time needed for fluoroscopy, and operation time, including establishment of navigation system, software interface operation, and screw insertion, were recorded. RESULTS: All the screws were inserted to the satisfying positions: placed within the desired bony corridor of the column and none of then were inserted into the joint. While inserting the screw into the anterior column fluoroscopy should be conducted with obturated oblique view, obturated inlet view, obturated oblique outlet view, or pelvic AP view. While inserting the screw into the posterior column fluoroscopy should be conducted with iliac-oblique view, obturated oblique view, pelvic inlet view, or obturated oblique outlet view. The total surgical time required for screw insertion was 11.7 min for anterior column, and was 9.2 min for posterior column. 9.5 and 7.3 minutes were needed to position the C-arm X-ray machine so as to obtain the images of the anterior and posterior columns respectively. 2.9 and 1.7 seconds were needed for the actual fluoroscopy during insertion of the screws into the anterior and posterior columns respectively. CONCLUSION: The standard registered fluoro-images are different from the conventional standard Judet-Letournel oblique views. How to get appropriate fluoro-images is the key point for fluoro-navigated percutaneous fixation of acetabular fractures.

[Accurate traction of long bone fracture with full-length planning module of orthopedic robot system: experiments in vitro and in vivo].

OBJECTIVE: To evaluate the precision in location and clinical flexibility of the newly designed full-length planning module of orthopedic robot system in treatment of fractures of long bone. METHODS: Nine plastic tibia models were selected for the image mosaicing. The full length of each tibia model was measured on the constructed panorama and compared with the real model length to record the length deviation and conduct the precision analysis. Fracture of tibia and fibula with shortening and angulation deformity was caused on a cadaver specimen with two lower limbs. Full-length planning was carried out on the entire tibial panorama with the fracture. After the reduction distance was determined quantitatively, automatic close traction procedure was carried out with the tibial reduction frame to analyze the precision and effectiveness of this module. At the same time, the relative length variation between the two bone fragments was monitored utilizing video camera to ensure the safety of the reduction operation. Image mosaicing, surgical planning, and bone traction were performed on a clinical case of tibial fracture to validate the clinical feasibility of the module. RESULTS: An entire tibial panorama could be constructed from 7 - 10 C-arm images collected during the operation. 1.5 min was needed for image collection. The average mosaicing and planning time was 3 min. The mosaicing error was less than 1.5 mm. The average time for the traction frame installation and traction operation was 4 min. Traction resulted in accurate reposition of the fracture ends meeting the requirement of surgery in both the cadaver specimen and the clinical case. CONCLUSION: The newly designed full-length planning module of orthopedic robot system is easy to use and provides effective and accurate traction result in long bone fracture therapy. This module can not only achieve the minimally invasive surgery, but also dramatically decrease the radiation damage to the medical staff.

[Intra-operative stereotactic accuracy of computer-assisted robot orthopaedic trauma surgery planning system].

OBJECTIVE: To investigate the feasibility and accuracy of the software computer-assisted robot orthopaedic trauma surgery planning system (CAOTS). METHODS: The software CAOTS was developed and used on 85 cases of stereotactic operation, 24 model bones, 21 cadaveric extremity bones, and 40 patients. 307 groups of directional targets in these cases were randomly sampled. The distribution of error sources for evaluating system performance was embodied using Monte-Carlo method in order to derive the theoretic guarantees for further optimizing and enhancing the system performance, then the software SPSS 2.0 was used to analyze the errors. RESULTS: The statistical area of deviation number was 0.0408 +/- 0.4578 mm, corresponding to the result by Monte-Carlo method. Punching succeeded at the first run for all 307 cases without wrong locking and other clinical complications. CONCLUSION: Accurate and reliable, CAOTS improves the intra-operative navigation techniques and facilitates the orthopedists to perform operation.

[Effects of medical robot-assisted surgical navigation system in distal locking of femoral intramedullary nails: an experimental study].

OBJECTIVE: To investigate the effects of medical robot-assisted surgical navigation system based on fluoroscopic images in distal locking of femoral intramedullary nails. METHODS: Using a robot-assisted computer-guided system designed based on modularization and minimization that permitted C-arm alignment assistance and real-time navigation control, provided constant feedback without the need for radiologic updates, thus avoiding constant X-ray exposure. The C-arm was used to collect the orthotopic and lateral X-ray images into the computer so as to calculate the locations of the target points. Nails were locked into 5 plastic femurs (Swiss Sybone, 35 holes), 2 dry human femoral specimens (12 holes), and one leg of fresh human cadaver (6 holes). Radiographs were taken to confirm that screws were positioned correctly, and fluoroscopic time associated with the locking procedure was recorded. RESULTS: All distal holes were locked successfully. In 6 (11.1%) of the 53 holes the drill bit touched the canal of the locking hole, albeit with no damage to the nail. The fluoroscopy time of per screw was 1.83 +/- 0.31 seconds. CONCLUSION: The medical robot-assisted surgical navigation system enables the physicians to precisely navigate surgical instruments throughout the procedure using just a few computer-calibrated radiographic images. The total radiation time per procedure can be significantly reduced because additional X-ray exposure is not required for tool navigation. The idea of a robot-assisted surgical navigation system is practicable.

Computer-assisted auto-frame navigation system for distal locking of tibial intramedullary nails: a preliminary report on clinical application.

OBJECTIVE: To evaluate the clinical feasibility and effect of the computer-assisted auto-frame navigation system for distal locking of tibial intramedullary nails. METHODS: The hardware components of the system included a PC computer with a monitor, auto mechanical stereotactical localization cubic frame, foot holder and localization operative apparatus. Special navigation software can be used for registration of X-ray fluoroscopic images and real-time controlling navigation of tools. Twenty-one cases of close tibial and fibular fractures were treated with closed intramedullary nailing, 6 of which involved in middle third, 12 in middle and lower third, 3 in lower third. C-arm alignment and registration time, fluoroscopic time and drilling time involved in the locking procedure were recorded. The size of unreamed or reamed tibial nails ranged from 8/300-11/330. RESULTS: All distal holes except 1 were locked successfully. In 9 of 41 locked holes (21.95%), the drill bit touched the canal of locking hole without damage of the nail and clinical consequences. The fluoroscopy time per pair of screws was 2.23+/-0.31 s. CONCLUSIONS: The computer-assisted auto-frame navigation system for distal locking is well designed, easy to operate and do not need additional instruments during the procedure. The developed system enables the physician to precisely navigate surgical instruments throughout the anatomy using just a few computer-calibrated radiographic images. The total time of X-ray exposure per procedure can be significantly reduced.