Computer-aided Navigation System Research Articles

Abdominal organ segmentation via deep diffeomorphic mesh deformations

Abdominal organ segmentation from CT and MRI is an essential prerequisite for surgical planning and computer-aided navigation systems. It is challenging due to the high variability in the shape, size, and position of abdominal organs. Three-dimensional numeric representations of abdominal shapes with point-wise correspondence to a template are further important for quantitative and statistical analyses thereof. Recently, template-based surface extraction methods have shown promising advances for direct mesh reconstruction from volumetric scans. However, the generalization of these deep learning-based approaches to different organs and datasets, a crucial property for deployment in clinical environments, has not yet been assessed. We close this gap and employ template-based mesh reconstruction methods for joint liver, kidney, pancreas, and spleen segmentation. Our experiments on manually annotated CT and MRI data reveal limited generalization capabilities of previous methods to organs of different geometry and weak performance on small datasets. We alleviate these issues with a novel deep diffeomorphic mesh-deformation architecture and an improved training scheme. The resulting method, UNetFlow, generalizes well to all four organs and can be easily fine-tuned on new data. Moreover, we propose a simple registration-based post-processing that aligns voxel and mesh outputs to boost segmentation accuracy.

Robotic Systems and Navigation Techniques in Orthopedics: A Historical Review

Since the da Vinci surgical system was approved by the Food and Drug Administration (FDA) in 2000, the development and deployment of various robot-assisted minimally invasive surgery (MIS) systems have been largely expedited and boomed. With the rapid advancement of robotic techniques in recent decades, robot-assisted systems have been widely used in various surgeries including orthopedics. These robot-related techniques are transforming the conventional ways to conduct surgical procedures. Robot-assisted orthopedic surgeries have become more and more popular due to their potential benefits of increased accuracy and precision in surgical outcomes, enhanced reproducibility, reduced technical variability, decreased pain, and faster recovery time. In this paper, robotic systems and navigation techniques in typical orthopedic surgeries are reviewed, especially for arthroplasty. From the perspective of robotics and engineering, the systems and techniques are divided into two main categories, i.e., robotic systems (RSs), and computer-aided navigation systems (CANSs). The former is further divided into autonomous RS, hands-on RS, and teleoperated RS. For the latter, three key elements in CANS are introduced, including 3D modeling, registration, and navigation. Lastly, the potential advantages and disadvantages of the RS and CANS are summarized and discussed. Future perspectives on robotics in orthopedics, as well as the challenges, are presented.

The Role of Intraoperative Navigation in Surgical Treatment of Unilateral Zygomatic Complex Fractures: A Systematic Review and Meta-Analysis

The application of a computer-aided navigation system (CANS) in zygomatic complex (ZMC) fractures has been extensively reported, but individual results are heterogeneous. The purpose of this systematic review was to evaluate the role of CANS in the surgical treatment of unilateral ZMC fractures. Electronic retrieval of MEDLINE, Embase, and Cochrane Library (CENTRAL) and manual searching until November 1, 2022 were used to identify cohort studies and randomized controlled trials employing CANS in the surgical treatment of ZMC fractures. The identified reports contained at least 1 of the following outcome variables: accuracy of reduction, total treatment time, amount of bleeding, postoperative complications, satisfaction, and cost. Weighted or mean differences (MD), risk ratios, and corresponding 95% confidence intervals (CI) were calculated, where P＜.05 and I2＞50% random-effect model was adopted, and a vice versa fixed-effect model was adopted. Descriptive analysis was applied to qualitative statistics. The protocol was conducted in accordance with PRISMA guidelines and prospectively registered with PROSPERO (CRD42022373135). A total of 562 studies were identified, of which 2 cohort studies and 3 randomized controlled trials with 189 participants were included. Meta-analysis indicated that employing CANS significantly decreased the reduction error (MD=-0.86, 95% CI -1.58 to -0.14; P=.02, random-effect model) compared with conventional surgery without using CANS. The differences in total treatment time (preoperative planning time: MD=1.44, 95% CI -3.55 to 6.43; P=.57 and operative time: MD=3.02, 95% CI -9.21 to 15.26; P=.63, fixed-effect model) and amount of bleeding (MD=14.86, 95% CI -8.86 to 38.58; P=.22, fixed-effect model) were not statistically significant between the two groups. Descriptive analysis suggested that postoperative complications, postoperative satisfaction, and cost were also similar with or without CANS. Within the limitations of the present review, the reduction accuracy of unilateral ZMC fractures using CANS is superior to that of conventional surgery. CANS presents limited influence on operation time, amount of bleeding, postoperative complications, postoperative satisfaction, and cost.

Fusion of multimodality image and point cloud for spatial surface registration for knee arthroplasty

Image-guided computer-aided navigation system is an indispensable part of computer assisted orthopaedic surgery. However, the location and number of fiducial markers, the time required to localize fiducial markers in existing systems affect their effectiveness. The study proposed that spatial surface registration between the point cloud on the surface of the fusion model based on preoperative knee MRI and CT images and the point cloud on the cartilage surface captured by intraoperative laser scanner could solve the above limitations. The experimental results show that the registration error of the method is less than 2mm, but the total time from scanning the point cloud on patient's cartilage surface to registering it with the point cloud in preoperative image space is less than 2 minutes. The method achieves the registration accuracy similar to existing methods without selecting anatomical corresponding points, which is of great help to the clinic. This article is protected by copyright. All rights reserved.

Arthroscopic Debridement of Elbow Osteoarthritis Using CT-Based Computer-Aided Navigation Systems Is Accurate

PurposeTo evaluate whether the bony impingement lesion in elbow osteoarthritis can be removed accurately, as planned during arthroscopy, by using the computer-aided navigation system and performing mock surgery using 3-dimensional (3D)-printed bone models for clinical applications.MethodsWe performed mock surgery using 3D-printed plaster bone models of the humerus of 15 actual patients with elbow osteoarthritis. Two types of experiments were conducted to evaluate the surgical accuracy. Three surgeons performed the mock surgery, each with 15 bone models (total, 45 trials). Surgical accuracy was based on the mean of 45 trials. The differences in surgical accuracy among the 3 surgeons were also evaluated (mean 15 trials). The same surgeon performed 30 trials, and the difference in surgical accuracy between the first and the second halves was also evaluated (mean 15 trials).ResultsThe spatial error in the entire elbow joint was 1.13 mm. In terms of resection volume, a mean of 8% more volume was resected than was planned, and 85% of the planned area was resected. In our experiments, the surgical accuracy was significantly lower in the anterior than in the posterior joint. Intrarater reliability was intraclass correlation (ICC)2,1 0.81 and inter-rater reliability was ICC1,1 0.87.ConclusionsSurgery using computer-aided navigation systems for arthroscopic debridement of the elbow provided accuracy comparable to that in other joints.Clinical RelevanceArthroscopic debridement of elbow osteoarthritis requires advanced surgical skills because accurate identification of the bony impingement legion is difficult during surgery. Surgery using computer-aided navigation systems for arthroscopic debridement of the elbow will provide real-time tracking of both the surgical instruments and bony impingement lesions as well as solve the technical difficulties of arthroscopic surgery of the elbow joint.

A new technique useful for lumbosacral percutaneous pedicle screw placement without fluoroscopy or computer-aided navigation systems

BackgroundPercutaneous pedicle screw (PPS) placements in the lumbosacral spine generally rely on fluoroscopy at the expense of radiation exposure. Our accumulated experience in open PS placements without fluoroscopic guidance realized a consistent shift toward PPS insertion with newly developed devices, which require neither fluoroscopy nor navigation. We wish to report our new technique and evaluations of its accuracy. MethodsOur equipment consisted of a pedicle targeting tool to identify and escort the cannulated awl to the correct starting point for cortical bone perforation and a cannulated awl-probe system with a guidewire to maintain the optimal position throughout the subsequent surgical steps. The surgeon could advance the blunt-tipped probe searching for the cancellous bone track using tactile feedback as experienced in open techniques. A 2-year period of transition from a free-hand (1169 screws in 286 patients) to the new PPS technique (1933 screws in 413 patients) allowed accuracy comparison between the two procedures using postoperative CT scans. ResultsCompared with the open-group, the PPS-group showed a lower rate of fully contained intrapedicular PS placements at L1 through S1, as a whole (90.7% vs 85.4%), but not at L4 through S1 (89.9% vs 90.2%). Less-accurate PPS placements at upper than lower lumbar spines in part reflect intended pedicle perforations laterally as a trade-off for avoiding facet violation immediately above the most cephalad screw. The PPS-group also had a higher incidence of PS-related transient nerve root complications (0% vs 1.7%). These values for the PPS-group, however, fell within those previously reported for free-hand or fluoroscopy techniques. ConclusionsOur new PPS technique, although useful for eliminating the potential risk of repeated radiation exposure, fell short of reaching the accuracy of the free-hand technique. Nerve integrity monitoring with PS stimulation, which we currently use, will help further improve the technical precision. Study designOriginal Article. The study was approved by our institutional review boad (2,019,231).

Application of aided three-dimension CT navigation system in craniocervical junction malformation disease surgery

To investigate the related problems of three-dimension CT navigation system applied to craniocervical junction malformation diseases surgery. The clinical data of 61 patients with craniocervical junction malformation disease who underwent surgical treatment from July 2015 to March 2018 was retrospectively analyzed. There were 39 males and 22 females aged from 25 to 73 years old with a mean of (46.20±12.09) years. According to the different ways of screw placements, these patients were divided into navigation group (30 cases) and non navigation group (31 cases). The screws insertion in the navigation group were guided under three-dimension CT computer-aided navigation system, while the screws insertion were guided by C-arm fluoroscopy and intraoperative anatomical landmarks in non-navigation group. All surgeries were performed by the same group of surgeons. All cases were scanned by CT after operation to assess the accuracy of the screw insertion. A total of 122 screws were inserted in the study, including 60 screws in navigation group and 62 screws in non-navigation group. The screw positions in navigation group were all satisfactory, and there were no screw-related complications. The position of 3 screws (4.83%) in non-navigation group was not satisfactory, and there was no obvious neurological symptoms after operation. The operation time of navigation group was from 87.5 to 112.5 min with a mean of (99.6± 12.0) min;and non-navigation group was from 87.5 to 107.5 min, with a mean of (97.5±10.5) min. There was no statistically significant difference in the operation time between two groups (P>0.05). The screw insertion time in navigation group was from 1.50 to 4.20 min, with a mean of (2.51±1.02) min;and non navigation group was from 1.80 to 5.10 min, with a mean of (3.25±1.05) min. The screw insertion time in navigation group was shorter than that in non-navigation group (P<0.05). The intraoperative blood loss in navigation group was from 122 to 153 ml, with a mean of (137.57±9.48) ml, which in non-navigation group wasfrom 121 to 158 ml, with a mean of (138.75±8.56) ml, there was no statistically significant difference between two groups (P>0.05). The three-dimensional CT computer-aided navigation system has the characteristics of clear imaging and accurate positioning, which can help improve the accuracy and safety of the screw insertion in craniocervical junction malformation disease surgery.

Process analysis and application summary of surgical navigation system

In recent years, with the rapid development of computer image processing technology, medical image technology and location tracking technology, computer-aided navigation system helps doctors to determine the best surgical path through preoperative diagnosis, operation path planning, registration and intraoperative navigation, which makes the operation more accurate, rapid and safe, and opens up a new field for the development of surgery. In this paper, the key technologies, process analysis, function realization and clinical application progress of surgical navigation system are briefly summarized. Finally, this paper also makes a prospect for the development trend of surgical navigation technology.

Accuracy of Dynamic Computer-Aided Navigation System for Dental Implant Placement

Accuracy of Dynamic Computer-Aided Navigation System for Dental Implant Placement

Navigated robotic assistance results in improved screw accuracy and positive clinical outcomes: an evaluation of the first 54 cases

Computer-aided navigation and robotic guidance systems have become widespread in their utilization for spine surgery. A recent innovation combines these two advances, which theoretically provides accuracy in spinal screw placement. This study describes the cortical and pedicle screw accuracy for the first 54 cases where navigated robotic assistance was used in a surgical setting. This is a retrospective chart review of the initial 54 patients undergoing spine surgery with pedicle and cortical screws using robotic guidance with navigation. A computed tomography (CT)-based Gertzbein and Robbins System (GRS) was used to classify pedicle screw accuracy. Screw tip, tail, and angulation offsets were measured using image overlay analysis. Screw malposition, reposition, and return to operating room rates were collected. 1 of the first 54 cases was a revision surgery and was excluded from the study. Ten screws were placed without the robot due to surgeon discretion and were excluded for the data analysis of 292 screws. Only 0.68% (2/292) of the robot-assisted screws was repositioned based on surgeon discretion. Based on the GRS CT-based grading, 98.3% (287/292) were graded A or B, 1.0% (3/292) screws were graded C, and only 0.7% (2/292) screws was graded D. The average offset from preoperative plan to actual final placement was 1.9 mm from the tip, 2.3 mm from the tail, and 2.8° of angulation. In the first 53 cases, 292 screws placed with navigated robotic assistance resulted in a high level of accuracy (98.3%), adequate screw offsets from planned trajectory, and zero complications.

Role of computer aided navigation system for surgical treatment of extensive sinonasal polyposis

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; The aim of the study was to study the role of computer aided endoscopic sinus surgery for treatment of extensive sinonasal polyposis by comparing cases with and without navigation.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; A prospective study of 75 patients with extensive nasal polyposis attending outpatient section of department of ENT, BLDE University’s Sri BM Patil Medical College, Hospital, Vijaypur was done from January 2015 to December 2017. 37 cases were randomly subjected to surgery with navigation. Other group included 38 cases which underwent surgery without navigation. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; A total of 75 cases of which 39 were males and 36 females with an age range of 9-76 years. Patients were studied for preoperative and postoperative SNOT-22 symptom scores. These values showed significant improvement with p&amp;lt;0.001. The comfort level of the surgeon intraoperatively was good in 89.18%, medium in 10.8% and bad in 0% cases in navigation guided surgeries. Whereas in surgeries without navigation, it was good in 78.9%, medium 10.52% and bad in 10.52% cases. Intraoperatively disease clearance adequacy was partial in 1 case (2.7%) and total in 36 cases (97.3%). In cases without navigation, the scores were 4 (10.5%) partially cleared, 34 (89.5%) totally cleared. No major (0%) and one minor complication, 1(3%) in surgery with navigation occurred. In group without navigation guided surgery, Major complication was 13% and minor was 11%. These values are indicative of P value 0.021.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; The computer aided navigation guided surgery is a necessary tool in cases of extensive lesions like sinonasal polyposis.&lt;/p&gt;

Laparoscopic ultrasound manipulator with a spring-based elastic mechanism.

Image guidance is a key technology that can improve the outcome of laparoscopic surgery. However, due to the large deformation caused by digestive organs, a computer-aided navigation system based on preoperative imaging data cannot indicate the correct target position of the lesion (e.g., liver tumors and vessels invisible from the organ surface). To overcome this issue, we developed a laparoscopic ultrasound manipulator with two motorized degrees of freedom at the tip, allowing for the performance of a dexterous ultrasound scan in a confined laparoscopic surgical area. The developed manipulator consists of a compact and elastic structure using springs, enabling a safe ultrasound scan and avoiding excess force on the inspected organs. The manipulator is a handheld device equipped with four buttons at the handle, which the surgeon directly grasps to send a motion command to the tip structure. The developed prototype realizes two motorized degree-of-freedom motion at the tip. The size of prototype is 15.0mm in diameter that is usable in conventional laparoscopy. The tip of the manipulator was carefully designed by considering the kinematic model and the results of the finite element analysis. To assess the prototype, accuracy and rigidity were measured by using a motion processing microscope. The accuracy test showed that the proposed device has a fairly accurate characteristic as a handheld device. This was supposedly caused by the nature of compliant mechanism, which does not have mechanical play in motion. In addition, the intrinsic elastic structure (approximately 2.0N/mm in most of the range of motion) allowed the ultrasound probe to adequately fit on the curved organ surface without extra effort of manipulation during the inspection. In the in vivo experiment, the yaw motion was found to be effective for investigating the vascular network because the manipulator allows the probe to be rotated while maintaining the same position. The mechanical evaluation and in vivo test results showed high feasibility of the prototype. We are currently working on further mechanical improvement for commercialization and development of a real-time navigation system that can perform three-dimensional reconstruction of ultrasonographic images by implementing a magnetic position sensor at the tip of the manipulator.

Computer-aided navigation system in treatment of children with the diseases of the nasal cavity and paranasal sinuses

The use of minimally invasive methods of surgical treatment is preferable in children’s otorhinolaryngology. The use of navigation system in rhinosurgery provides the improvement of endoscopic interventional technique, the avoidance of damage of the adjacent vital anatomical structures, planning the scope of surgical treatment, thus decreasing the risk of post-surgical complications in pediatric practice. This article describes successful application of the navigation system in surgery of various nasal cavity and paranasal sinuses diseases in 25 children.

A Robotic Flexible Drill and Its Navigation System for Total Hip Arthroplasty

This paper presents a robotic flexible drill and its navigation system for total hip arthroplasty (THA). The new robotic system provides an unprecedented and unique capability to perform curved femoral milling under the guidance of a multimodality navigation system. The robotic system consists of three components. Firstly, a flexible drill manipulator comprises multiple rigid segments that act as a sheath to a flexible shaft with a drill/burr attached to the end. The second part of the robotic system is a hybrid tracking system that consists of an optical tracking system and a position tracking system. Optical tracking units are used to track the surgical objects and tools outside the drilling area, while a rotary encoder placed at each joint of the sheath is synchronized to provide the position information for the flexible manipulator with its virtual object. Finally, the flexible drill is integrated into a computer-aided navigation system. The navigation system provides real time guidance to a surgeon during the procedure. The flexible drill system is then able to implement THA by bone milling. The final section of this paper is an evaluation of the flexible and steerable drill and its navigation system for femoral bone milling in sawbones.

3D-Navigated Implantation of Pedicle Screws in the Cervical Spine - Experience and Analysis of Complications

Background: Placing transpedicular screws in the cervical spine is a special challenge for spine surgeons, due to the anatomical features of this part of the spine. During the last 15 years, computer-aided navigation systems have been developed to facilitate this procedure and to make it safer for patients. One option is navigation by intraoperatively acquired data sets with the use of an 3D C-arm. Patients/Material and methods: Our retrospective study evaluates transpedicular screws in the cervical spine placed by 3D C-arm navigation, within a 6 year period in a level 1 trauma centre. We recorded epidemiological data, operation time and especially general adverse events, as well as revision surgery, including reasons for revision. We used a C-arm Arcardis Orbic 3D (Siemens, Munich), connected to a navigation system (VectorVision, Brainlab, Munich). Results: Between July 2007 and July 2013, 207 transpedicular screws were placed in 58 patients. The main indications were trauma (69 %), rheumatic diseases (20.7 %) and tumour (8.6 %). The most commonly instrumented cervical spine segments were C2 (53.5 %)%), C7 (10.3 %) and C5 (8.6 %). In nearly 95 % of the cases, we performed an intraoperative 3D scan after screw or k-wire placement to control the screw position. We found unacceptable malposition in 7.2 % of patients. This was corrected at once. Ten patients had to be revised: seven times due to wound problems, twice because of implant failure and once for treatment of CSF leakage. Three screws (1.5 %) led to injuries of the vertebral artery, once with a lethal outcome. Analysis of these cases showed that the 3D scan gave reduced data quality, due to reduced bone density or anatomical factors. Conclusion: Intraoperative 3D C-arm navigation seems to be a reliable option for transpedicular screw placement in the cervical spine. Complication rates were comparable to published values. 7.2 % of all screws were corrected intraoperatively after a control scan. Therefore possible revisions could be avoided during primary surgery. Analysis of problematic cases led to a change in our treatment strategy: in patients with poor bone quality and/or anatomical problems which lead to 3D scans of poor quality, we avoid transpedicular screw placement in C6 or higher, in order to prevent injuries of the vertebral artery.

Computer-Assisted Mandibular Reconstruction with Monocortical DCIA Flap; A Case Report

Recently, computer-assisted surgery is popular for performing well-planned operations. Computer-aided navigation system is helpful in maxillofacial surgery with real time instrument positioning and clear anatomic identification. Generally, segmental mandibulectomy and reconstruction flap surgery have done by extra-oral approach such as, submandibular approach. This case report describes performing intra-oral segmental mandibulectomy and reconstruction with monocortical deep circumflex iliac artery (DCIA) flap and CT guided implant surgery by using computer-aided surgical guide and navigation for managing ameloblastoma in a 31 years old female patient.

Influence of the two-dimension computer-aided navigation system to the concordance of lumbar spine pedicle screw fixation on both sides

Objective To investigate the influence of the two-dimension computer-aided surgery navigation system to the concordance of lumbar spine pedicle screw fixation on both sides.Methods 1355 patients were undergone lumbar spinal pedicle screw fixation during January 2004 to December 2009.All patients were divided into tow groups:the navigation group (743cases) and the fluoroscopy assistant group (612 cases).All patients got standard A-P and lateral X-ray plate of lumbar spine within seven days after surgery.The X-ray images were analyzed by the software of Image-pro plus 5.0 to evaluate the concordance of lumbar spine pedicle screw fixation on both sides.The angle between axial line of pedicle screw and superior lamina terminals (α angle) and the angle between axial lines of pedicle screw on both sides (γangle) were measured.The position of the pedicle screw was checked weather it was in the lumbar pedicle partially.Results There were no significant differences (P＞0.05) between the α angle on both sides of L1-S5 vertebral body in navigation assistant group (L:3.89°±0.47°,R:3.94°±0.37°).The differences of the α angle on both sides of L2 (L:4.55°±1.27°,R:5.12°±1.87°) and L4 (L:4.22°±1.89°,R:6.62°±1.97°) vertebral body in the fluoroscopy assistant group had statistical significance (P＜0.05).There were no significant differences between the α angle on both sides of other bodies (L:4.32°±1.47°,R:4.37°±1.59°,P＞0.05).The γangle in navigation assistant group (2.32°± 0.27°) was obviously smaller than fluoroscopy assistant group (3.32°±1.51°),the differences had statistical significance (P＜0.05).Accuracy of pedicle screw in navigation assistant group was 91.5％ (3604/3938).Accuracy of pedicle screw in fluoroscopy assistant group was 87.6％ (2426/2768).The difference in accuracy of pedicle screw in both groups had statistical significance (x2=26.913,P＜0.0001).Conclusion The accuracy of pedicle screw and the concordance of pedicle screw on both sides can be significantly improved using the two-dimension perspective computer-aided surgery navigation system. Key words: Lumbar vertebrae; Surgery, computer-assisted; Internal fixators

Application of surgical navigation in treatment of pelvic fractures in the Lushan earthquake rescue

Objective To report our clinical experience of using computer-aided orthopedic surgery (CAOS) in the treatment of patients with pelvic fracture who had been injured in the earthquake at Yaan,Lushan,Sichuan,China.Methods From 20 April to 3 May,2013 we treated 6 patients with pelvic fracture using CAOS in the Lushan earthquake rescue.They were 3 men and 3 women,aged from 20 to 54years (average,39.7 years).By the Tile classification,there were 2 cases of type B and 4 cases of type C.One case was complicated with open fractures of bilateral tibias,2 with costal fracture,3 with femoral fracture,2 with lumbar fracture,one with patellar fracture,one with humeral fracture,and 5 with skin contusion.The 6 patients received surgery under computer-aided navigation system 3 to 10 days after injury (average,6days).X-ray follow-ups of the pelvis were conducted post-surgery and the therapeutic effects were assessed by the Matta criteria.Results Altogether 11 cannulated screws were implanted,including 6 sacroiliac screws (5 S1 ones and one S2) and 5 pubic ramus screws (2 antegrade ones and 3 retrograde ones).All the surgeries went on uneventfully with no neurovascular injury.The average amount of bleeding for each cannulated screw was 20 mL.The total intraoperative bleeding ranged from 60 to 200 mL,averaging 110 mL.The time of radiation exposure for each screw averaged 10 seconds and the operative time 110 minutes.Postoperative review of the pelvic X-ray films showed satisfactory fracture reduction.Four cases were rated as excellent and 2 as good.All the surgical wounds healed primarily with no wound infection,deep vein thrombosis,multiple organ dysfunction syndrome or other complications.Conclusion CAOS is a feasible,safe and effective method for treatment of pelvic fractures in an earthquake rescue not only because it has common advantages of minimal invasion,high accuracy,less radiation exposure,shorter operative time and early stabilization but also because it can provide damage control for the patients who have been severely injured in the earthquake. Key words: Pelvis; Fracture, bone; Multiple trauma; Surgery, computer-assisted; Earthquakes

Application of computer navigation system in the treatment of post-traumatic reconstruction

To investigate the value of computer aided navigation system (CANS) in the treatment of post traumatic maxillofacial deformation. Fifty-four patients (M = 37, F = 17) were included in the study, including 31 cases of zygomatic fracture, 7 cases of pure orbital fracture, 11 cases of temporal mandibular joint ankylosis, 1 case of foreign body and 4 cases of defect reconstruction with custom implant. Data acquisition was done through CT scan, and DICOM data was transferred into workstation. Computer assisted design, including osteotomy, reposition, fibula flap design, orbital implant construction was performed using Surgicase CMF and Brain Lab Iplan system. The virtual design was transferred to Brain Lab navigation system, and the osteotomy, reduction, location of bone graft and custom implant were guided by navigation. Postoperative CT scan was required 48 - 72 hours after surgery. Preoperative and postoperative CT images were superimposed automatically in BrainLab Iplan system, and compared both in 3D objects and 2D slices. All the cases achieved good results without serious complication. The error of important corresponding points in zygomatic fracture reduction, orbital reconstruction and defect reconstruction was 0.2 - 3.5 mm, 0.8 - 2.0 mm and 0.2 - 2.2 mm respectively. Computer assisted design is of considerable value for the systematic and accurate planning for complicated post traumatic deformation. Virtual plan could be carried out accurately with the assistance of CANS.

Application of computer-aided surgical navigation system in orbital surgery

Computer-aided surgical navigation system, which is a combination of computer technology and medical imaging, is one of the most popular and developing fields in recent years. The navigation system is aimed to improve the accuracy and security of the surgery by pre-operative planning, intra-operative navigation and post-operative evaluation. This paper introduces the essential elements, fundamental principles, and implementation steps of the navigation system; further reviews its usefulness and progress in orbital fractures reduction, orbital tumor surgery and orbital decompression.