Application of computer-assisted navigation in treating congenital maxillomandibular syngnathia:A case report

BACKGROUND Congenital maxillomandibular syngnathia is an extremely rare disorder characterized by craniofacial malformations and inability to open the mouth adequately, which leads to problems with feeding, swallowing, and breathing as well as temporomandibular joint ankylosis. The main goal of the surgery is to release the ankylosis, establish functioning mandible, and prevent re-fusion.However, surgical procedures for this disease are rarely reported.CASE SUMMARY Here, we report a 7-mo-old girl with bilateral maxillomandibular syngnathia. The patient presented with difficulty in feeding, breathing, sounding, and swallowing and had developmental dysplasia. For treatment, we performed bone isolation by computer-assisted navigation and used silicone to fix the wound surface to prevent refusion of bone. To our knowledge, this is the only syngnathia case in the literature treated using computer-assisted navigation. With the guidance of precise navigation, we were able to minimize operation time by at least one hour,the patient's blood vessels, nerves, and tooth germs were well protected, and excessive bleeding was avoided. After six weeks, the patient showed improvement in mouth opening and no major issues of feeding.CONCLUSION Application of computer-assisted navigation can significantly improve accuracy,effectiveness, and surgical safety in correcting congenital maxillomandibular syngnathia.

Clinical application of improved 2D computer-assisted fluoroscopic navigation through simulating a 3D vertebrae image to guide pedicle screw internal fixation

Objective To study the effect of using improved 2D computer-assisted fluoroscopic navigation through simulating 3D vertebrae image to guide pedicle screw internal fixation.Methods Posterior pedicle screw internal fixation,distraction

Application of a novel computer-assisted surgery system in percutaneous nephrolithotomy:A controlled study

BACKGROUND Most complex renal stones are managed primarily with percutaneous nephrolithotomy(PCNL).However,PCNL is still a great challenge for surgeons because of poor comprehension on complex adjacent structures.Novel techniques are required to assist in planning and navigation.AIM To apply and evaluate the Hisense computer-assisted surgery(CAS)system in PCNL.METHODS A total of 60 patients with complex renal stones were included.Thirty patients in the CAS group had three-dimensional(3 D)virtual models constructed with the CAS system.The model assisted in planning and navigating in the CAS system.Thirty patients in the control group planned and navigated as standard PCNL,without the application of the CAS system.Success rate of one attempt,operation time,initial stone-free rate,decrease in hemoglobin,and complications were collected and analyzed.RESULTS There were no statistically significant differences in the baseline characteristics or planning characteristics.The success rate of one puncturing attempt(90%vs 67%,P=0.028)and the initial stone-free rate(87%vs 63%,P=0.037)were significantly higher in the CAS group.However,there were no statistically significant differences in the operation time(89.20±29.60 min vs 92.33±33.08 min,P=0.859)or in the decrease in hemoglobin(11.07±8.32 g/L vs 9.03±11.72 g/L,P=0.300)between the CAS group and the control group.No statistically significant differences in the incidence of complications(Clavien-Dindo grade≥2)were found.CONCLUSION Compared with standard PCNL,CAS-assisted PCNL had advantages in terms of the puncturing success rate and stone-free rate.The Hisense CAS System was recommended to assist in preoperative planning and intraoperative navigation for an intuitive,precise and convenient PCNL.

Novel computer-assisted method for revision arthroplasty of the knee

AIM: To introduce the navigation system of software and instruments designed specifically for revision total knee arthroplasty(TKA).METHODS: We present an imageless navigation system for revision TKA,with optical point and tracker identification to assess kinematic and anatomical landmarks.The system automatically positions the cutting guides with a motorized cutting unit.The cutting unit is placed on the distal femur with a femoral clamp and acts as a rigid body and the base for all femoral cuts.The surgical technique for using the navigation system for revision TKA is based on the technique used in primary TKA.However,there are some important differences.The most notable are:(1) differences in estimation of the position of the primary implant relative to the bone and the mechanical axes;(2) the specific possibilities the revision navigation software offers in terms of optimal joint level positioning; and(3) the suggested "best fit" position,in which the clock position,stem position and offset,femoral component size,and mediolateral position of the femoral component are taken into account to find the optimal femoral component position.We assessed the surgical technique,and accompanying software procedural steps,of the system,identifying any advantages or disadvantages that they present.RESULTS: The system aims to visualize critical steps of the procedure and is intended as a tool to support the surgeon in surgical decision-making.Combining a computer-assisted cutting device with navigation makes it possible to carry out precise cuts without pinning.Furthermore,the femoral clamp provides a stable fixation mechanism for the motorized cutting unit.A stable clamp is paramount in the presence of periarticular bony defects.The system allows the position of the primary implant relative to the bone and mechanical axes to be estimated,at which point any malalignments can be corrected.It also offers an optimal joint level position for implantation,and suggests a "best fit" position,in which the clock position,stem position and offset,femoral component size,and mediolateral position of the femoral component are considered.The surgeon can therefore make decisions intraoperatively to maximise alignment and,hence,outcomes.Based on the intraoperative findings of joint stability,the surgeon can modify the preoperative plan and switch from a constrained condylar system to a hinged version,or vice versa.CONCLUSION: The system is flexible and easy to learn and allows improvements in workflow during TKA.

Computer-Assisted Surgery for Mandibular Reconstruction Using a Patient-Specific Titanium Mesh Tray and Particulate Cancellous Bone and Marrow

Craniomaxillofacial surgery is difficult due to the complexity of the regional anatomy. Computer-assisted surgery is a promising tool aiming to improve the safety and precision of such surgery. A computer-assisted surgical navigation approach for reconstruction of mandibular defects using a patient-specific titanium mesh tray and particulate cancellous bone and marrow (PCBM) harvested from bilateral anterior ilia is proposed. This case report involves a large multicystic ameloblastoma affecting the right mandible of a 31-year-old male patient. Following detailed clinical examination, radiological interpretation, and histopathological diagnosis, computer-assisted surgical simulation with a virtual 3-dimensional (3-D) model was designed using surgical planning software based on the pre-operative computed tomography data. Long-span segmental resection of the mandible was planned, and the defect was analyzed for reconstruction using a patient-specific reconstruction titanium mesh tray mediated with computer-aided design and manufacturing (CAD/CAM) techniques. During the actual surgery, the ultrasonic bone cutting instrument in the surgeon’s hand was connected to the navigation system to touch an anatomical position on the patient. Therefore, osteotomies were performed finely and smoothly according to the navigation images of the cutting bone line by sequentially moving the instrument. Finally, a CAD/CAM-mediated titanium mesh tray condensed by PCBM was adapted to the remaining mandibular fragments. Six months postoperatively, the patient had a good mandibular configuration and facial contour. Integration of different technologies, such as software planning and 3-D surgical simulation, combined with intraoperative navigation and CAD/CAM techniques, provides safe and precise mandibular reconstruction surgery.

Lumbar spine superior-level facet joint violations： percutaneous versus open pedicle screw insertion using intraoperative 3-dimensional computer-assisted navigation

Background Percutaneous pedicle screw use has a high rate of cranial facet joint violations （FVs） because of the facet joint being indirectly visualized.Computer-assisted navigation shows the anatomic structures clearly,and may help to lower the rate of FVs during pedicle screw insertion.This study used computed tomography （CT） to evaluate and compare the incidence of FVs between percutaneous and open surgeries employing computer-assisted navigation for the implantation of pedicle screw instrumentation during lumbar fusions.Methods A prospective study,including 142 patients having lumbar and lumbosacral fusion,was conducted between January 2013 and April 2014.All patients had bilateral posterior pedicle screw-rod instrumentation （top-loading screws） implanted by the same group of surgeons; intraoperative 3-dimensional computer navigation was used during the procedures.All patients underwent CT examinations within 6 months postoperation.The CT scans were independently reviewed by three reviewers blinded to the technique used.Results The cohort comprised 68 percutaneous and 74 open cases （136 and 148 superior-level pedicle screw placements,respectively）.Overall,superior-level FVs occurred in 20 patients （20/142,14.1％）,involving 27 top screws （27/284,9.5％）.The percutaneous technique （7.4％ of patients,3.7％ of top screws） had a significantly lower violation rate than the open procedure （20.3％ of patients,14.9％ of top screws）.The open group also had significantly more serious violations than did the percutaneous group.Both groups had a higher violation rate when the cranial fixation involved the L5.A 1-level open procedure had a higher violation rate than did the 2-and 3-level surgeries.Conclusions With computer-assisted navigation,the placement of top-loading percutaneous screws carries a lower risk of adjacent-FVs than does the open technique; when FVs occur,they tend to be less serious.Performing a single-level open lumbar fusion,or the fusion of the L5-S1 segment,requires caution to avoid cranial adjacent FVs.

Learning curve of computer-assisted navigation system in spine surgery

Background Spine surgery using computer-assisted navigation （CAN） has been proven to result in low screw misplacement rates, low incidence of radiation exposure and excellent operative field viewing versus the conventional intraoperative image intensifier （CⅢ）. However, as we know, few previous studies have described the learning curve of CAN in spine surgery.Methods We performed two consecutive case cohort studies on pedicel screw accuracy and operative time of two spine surgeons with different experience backgrounds, A and B, in one institution during the same period. Lumbar pedicel screw cortical perforation rate and operative time of the same kind of operation using CAN were analyzed and compared using CⅢ for the two surgeons at initial, 6 months and 12 months of CAN usage.Results CAN spine surgery had an overall lower cortical perforation rate and less mean operative time compared with CⅢ for both surgeon A and B cohorts when total cases of four years were included. It missed being statistically significant,with 3.3% versus 4.7% （P=0.191） and 125.7 versus 132.3 minutes （P=0.428） for surgeon A and 3.6% versus 6.4%（P=0.058）, and 183.2 versus 213.2 minutes （P=0.070） for surgeon B. in an attempt to demonstrate the learning curve,the cases after 6 months of the CAN system in each surgeon＇s cohort were compared. The perforation rate decreased by 2.4% （P=0.039） and 4.3% （P=0.003） and the operative time was reduced by 31.8 minutes （P=0.002） and 14.4 minutes （P=0.026） for the CAN groups of surgeons A and B, respectively. When only the cases performed after 12 months using the CAN system were considered, the perforation rate decreased by 3.9% （P=0.006） and 5.6% （P 〈0.001） and the operative time was reduced by 20.9 minutes （P 〈0.001） and 40.3 minutes （P 〈0.001） for the CAN groups of surgeon A and B, respectively.Conclusions In the long run, CAN spine surgery decreased the lumbar screw cortical perforation rate and operative time. The learning curve showed a sharp drop after 6 months of using CAN that plateaued after 12 months; which was demonstrated by both perforation rate and operative time data. Careful analysis of the data showed CAN is especially useful for less experienced surgeon to reduce perforation rate and intraoperative time, although further comparative studies are anticipated.

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

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 hi.qh rates of failed matching procedures.

Minimally invasive transforaminal lumbar interbody fusion aided with computer-assisted spinal navigation system combined with electromyography monitoring

Background Minimally invasive techniques are gaining wide-spread application in lumbar fusion surgery, because they may have advantage over conventional open surgery in approach-related morbidity. This research was aimed to evaluate the safety and accuracy of the techniques of minimally invasive transforaminal lumbar interbody fusion by using a computer-assisted spinal navigation system combined with electromyography monitoring. Methods Sixteen patients underwent minimally invasive transforaminal lumbar interbody fusion. A computer-assisted spinal navigation system and electromyography were used for guiding pedicle screw placement. The operative duration, blood loss, complications, and fluoroscopic time were recorded. Clinical outcome was assessed by Visual Analog Scale and Oswestry Disability Index. Radiographic images were obtained to evaluate the accuracy of pedicle screw placement and fusion rates. Results The Visual Analog Scale and Oswestry Disability Index scores were vastly improved postoperatively. A total of 64 pedicle screws were implanted and three were regarded as misplacement by post-operative CT scan. Three screw trajectories were adjusted according to intra-operative stimulus-evoked electromyography monitoring. The average fluoroscopy time in each patient was 31.8 seconds, which equals to 7.9 seconds per pedicle screw. No patients had instrument related neurological complications, infection, implant failure or revision. Successful fusion was found in all patients. Conclusions The combination of navigation system and real-time electromyography monitoring can make the minimally invasive operation more safe and accurate while decreasing radiation exposure time of the medical staff and patient and minimizing the chance and the degree of the pedicle screw misplacement.

Accuracy of pedicle screw placement in the thoracic and lumbosacral spines using O-arm-based navigation versus conventional freehand technique

The accuracy and safety of pedicle screw insertion was markedly improved with the introduction of intraoperative three-dimensional navigation system during the last decade. This study aimed to evaluate the accuracy of pedicle screw placement using O-arm-based navigation system versus conventional freehand technique. Methods: We reviewed the accuracy of 341 thoracic (n = 173) and lumbosacral (n = 168) pedicle screws placed in 60 consecutive patients using either O-arm-based navigation or freehand technique in the Department of Neurosurgery of Beijing Tsinghua Changgung Hospital between January 2015 and June 2018. Patient-specific characteristics, treatment-related characteristics, and screw-specific accuracy were analyzed. The accuracy of pedicle screw placement was measured by Gertzbein-Robbins scale and screw grades A and B were clinically acceptable. Results: One hundred ninety-one screws were inserted in the O-arm-based navigation group and 150 in the freehand group. One hundred eighty-three (95.81%) clinically acceptable screws were placed in the navigation group and 135 (90.00%) in the freehand group (p = 0.034). Twenty-three (6.74%) screw revisions were performed in the two groups (8 screws in the navigation group and 15 screws in the freehand group) and significant difference was observed in thoracic spine (p = 0.018), while no statistical significance was presented in lumbosacral spine (p >0.05). Twenty-four (12.57%) screws in the navigation group and 24 (16.00%) in the freehand group violated the cortex (p > 0.05). Medial screw deviation was the most common problem in the two groups. Conclusion: The O-arm-based navigation exhibits higher accuracy for pedicle screw insertion than the freehand insertion technique.

Application of intraoperative O-arm-assisted real-time navigation technique for spinal fixation

This study explored the combined use of the O-arm and real-time navigation during spinal fixation. The clinical data for 60 patients undergoing spinal fixation, at Beijing Tsinghua Chang Gung Hospital between May 5, 2015 and May 1, 2017, were retrospectively analyzed. Pre-, intra-, and postoperative imaging findings were assessed. The patients were classified into the occipitocervical fusion(32 cases) and thoracic/lumbar/sacral spine fixation(28 cases, including 6 cases of percutaneous pedicle screw) groups. Lesion resections were performed microscopically. An O-arm, combined with real-time navigation, was used to assess spinal fixation. Efficacy was evaluated using operative times, X-ray times, screw positioning, and complications. Within the occipitocervical fusion group, 182 screws were placed in the cervical spine and 96 in the occipital bone. However, 6 screws penetrated the bone cortex and were adjacent to the vertebral arteries, based on O-arm three-dimensional imaging; therefore, the precision rate was 96.7%. Within the thoracic/lumbar/sacral spine fixation group, 148 pedicle screws were implanted, with 4 initially outside the vertebral body,yielding a precision rate of 97.3%. Ten percutaneous pedicle screws were implanted and well positioned. O-arm scans were performed 3 times/patient, with an average of 20–30 min/time. Screw implantation times were 5–7 min(cervical spine), 8–10 min(thoracic spine), and 6–8 min(lumbar spine). Intraoperative O-arm scans, combined with real-time navigation technology, allow real-time observation of screw angles and depths, improving the accuracy and safety of posterior screw fixations and reducing the radiation dose and frequency experienced by patients and surgeons.

Comparison of the clinical accuracy of cervical （C2-C7） pedicle screw insertion assisted by fluoroscopy, computed tomography-based navigation, and intraoperative three-dimensional C-arm navigation

Background The complicated anatomy of the cervical spine and the variation among pedicles reduces the accuracy and increases the risk of neurovascular complications associated with screw implantation in this region. In this study, we compared the accuracy of cervical （C2-C7） pedicle screw fixation assisted by X-ray fluoroscopy, computed tomography （CT）-based navigation, or intraoperative three-dimensional （3D） C-arm navigation.Methods This prospective cohort study was performed in 82 consecutive patients who underwent cervical pedicle screw fixation. The accuracy of screw insertion was assessed by postoperative CT scan with 3D reconstruction. The accuracy of screw insertion was assessed as： excellent （screw completely within pedicle）; acceptable （≤ 1 mm screw outside pedicle cortex）; poor （〉1 mm screw outside pedicle cortex）.Results A total of 145 screws were inserted in 24 patients who underwent C-arm fluoroscopy. Of these, 96 screws （66.2%） were excellent, 37 （25.5%） were acceptable, and 12 （8.3%） were poor. One hundred and fifty-nine screws were inserted in 29 patients in the CT-based navigation group. Among these, 141 （88.7%） were excellent, 14 （8.8%） were acceptable, and 4 （2.5%） were poor. A total of 140 screws were inserted in 29 patients in the intraoperative 3D C-arm navigation group, of which 127 （90.7%） were excellent, and 13 （9.3%） were acceptable. No severe or permanent neurovascular complications associated with screw insertion were observed in any patient.Conclusione CT-based and intraoperative 3D C-arm navigation were similarly accurate, and were both significantly more accurate than C-arm fluoroscopy for guiding cervical pedicle screw fixation. They were able to accurately guide the angle and depth of screw placement using visual 3D images. These two techniques are therefore preferable for high-risk cervical pedicle screw fixation. The ease and convenience of intraoperative 3D C-arm navigation suggests that it may replace virtual-fluoroscopy and CT-based navigation systems in future clinical applications.

Computer Navigation-aided Resection of Sacral Chordomas

Background： Resection of sacral chordomas is challenging. The anatomy is complex, and there are often no bony landmarks to guide the resection. Achieving adequate surgical margins is, therefore, difficult, and the recurrence rate is high. Use of computer navigation may allow optimal preoperative planning and improve precision in tumor resection. The purpose of this study was to evaluate the safety and feasibility of computer navigation-aided resection of sacral chordomas. Methods： Between 2007 and 2013, a total of 26 patients with sacral chordoma underwent computer navigation-aided surgery were included and followed for a minimum of 18 months. There were 21 primary cases and 5 recurrent cases, with a mean age of 55.8 years old （range： 35 84 years old）. Tumors were located above the level of the $3 neural foramen in 23 patients and below the level of the $3 neural foramen in 3 patients. Three-dimensional images were reconstructed with a computed tomography-based navigation system combined with the magnetic resonance images using the navigation software. Tumors were resected via a posterior approach assisted by the computer navigation. Mean follow-up was 38.6 months （range： 18-84 months）. Results： Mean operative time was 307 min. Mean intraoperative blood loss was 3065 ml. For computer navigation, the mean registration deviation during surgery was 1.7 ram. There were 18 wide resections, 4 marginal resections, and 4 intralesional resections. All patients were alive at the final follow-up, with 2 （7.7%） exhibiting tumor recurrence. The other 24 patients were tumor-free. The mean Musculoskeletal Tumor Society Score was 27.3 （range： 19-30）. Conclusions： Computer-assisted navigation can be safely applied to the resection of the sacral chordomas, allowing execution of preoperative plans, and achieving good oncological outcomes. Nevertheless, this needs to be accomplished by surgeons with adequate experience and skill.

Computer navigation-aided joint-preserving resection and custom-made endoprosthesis reconstruction for bone sarcomas:long-term outcomes

Background:Computed tomography(CT)and magnetic resonance imaging(MRI)data can be fused to identify the tumor boundaries.This enables surgeons to set close but tumor-free surgical margins and excise the tumor more precisely.This study aimed to report our experience in performing computer navigation-aided joint-preserving resection and custom-made endoprosthesis reconstruction to treat bone sarcoma in the diaphysis and metaphysis of the femur and tibia.Methods:Between September 2008 and December 2015,24 patients with bone sarcomas underwent surgical resection and joint-sparing reconstruction under image-guided computer navigation.The cohort comprised 16 males and eight females with a median age of 19.5 years(range:12-48 years).The tumor location was the femoral diaphysis in three patients,distal femur in 19,and proximal tibia in two.The tumors were osteosarcoma(n=15),chondrosarcoma(n=3),Ewing sarcoma(n=3),and other sarcomas(n=3).We created a pre-operative plan for each patient using navigation system software and performed navigation-aided resection before reconstructing the defect with a custom-made prosthesis with extracortical plate fixation.Results:Pathological examination verified that all resected specimens had appropriate surgical margins.The median distance from the tumor resection margin to the joint was 30 mm(range:13-80 mm).The median follow-up duration was 62.5 months(range:24-134 months).Of the 24 patients,21 remain disease free,one is alive with disease,and two died of the disease.One patient developed local recurrence.Complications requiring additional surgical procedures occurred in six patients,including one with wound hematoma,one with delayed wound healing,one with superficial infection,one with deep infection,and two with mechanical failure of the prosthesis.The mean Musculoskeletal Tumor Society score at the final follow-up was 91%(range:80%-100%).The 5-and 10-year implant survival rates were 91.3%and 79.9%,respectively.Conclusions:Computer navigation-aided joint-preserving resection and custom-made endoprosthesis reconstruction with extracortical plate fixation is a reliable surgical treatment option for bone sarcoma in the diaphysis and metaphysis of the femur and tibia.

A retrospective study to compare the treatment outcomes with and without surgical navigation for fracture of the orbital wall

Purpose To evaluate the outcomes with and without aid of a computer-assisted surgical navigation system(CASNS)for treatment of unilateral orbital wall fracture(OWF).Methods Patients who came to our hospital for repairing unilateral traumatic OWF from 2014 to 2017 were included in this study.The patients were divided into the navigation group who accepted orbital wall reconstruction aided by CASNS and the conventional group.We evaluated the surgical precision in the navigation group by analyzing the difference between actual postoperative computed tomography data and preoperative virtual surgical plan through color order ratios.We also compared the duration of surgery,enophthalmos correction,restoration of orbital volumes,and improvement of clinical symptoms in both groups systemically.Quantitative data were presented as mean±SD.Significance was determined by the two-sample t-test using SPSS Version 19.0 A p<0.05 was considered statistically significant.Results Seventy patients with unilateral OWF were included in the study cohort.The mean difference between preoperative virtual planning and actual reconstruction outcome was(0.869±0.472)mm,which means the reconstruction result could match the navigation planning accurately.The mean duration of surgery in the navigation group was shorter than it is in the control group,but not significantly.Discrepancies between the reconstructed and unaffected orbital-cavity volume and eyeball projection in the navigation group were significantly less than that in the conventional group.One patient had remnant diplopia and two patients had enophthalmos after surgery in the navigation group;two patients had postoperative diplopia and four patients had postoperative enophthalmos in the conventional group.Conclusion Compare with the conventional treatment for OWF,the use of CASNS can provide a significantly better surgical precision,greater improvements in orbital-cavity volume and eyeball projection,and better clinical results,without increasing the duration of surgery.

Guidelines for navigation-assisted spine surgery

Spinal surgery is a technically demanding and challenging procedure because of the complicated anatomical structures of the spine and its proximity to several important tissues.Surgical landmarks and fluoroscopy have been used for pedicle screw insertion but are found to produce inaccuracies in placement.Improving the safety and accuracy of spinal surgery has increasingly become a clinical concern.Computerassisted navigation is an extension and application of precision medicine in orthopaedic surgery and has significantly improved the accuracy of spinal surgery.However,no clinical guidelines have been published for this relatively new and fast-growing technique,thus potentially limiting its adoption.In accordance with the consensus of consultant specialists,literature reviews,and our local experience,these guidelines include the basic concepts of the navigation system,workflow of navigation-assisted spinal surgery,some common pitfalls,and recommended solutions.This work helps to standardize navigation-assisted spinal surgery,improve its clinical efficiency and precision,and shorten the clinical learning curve.

Min-invasive surgical treatment for multiple axis fractures: A case report

BACKGROUND Fractures of the axis are commonly seen in spinal injuries. Upper cervical fractures are usually managed conservatively. However, the complications due to long-term external immobilization cannot be ignored. The traditional open surgery has the disadvantages of too much blood loss and soft tissue injury. The aim of our paper is to introduce a minimally invasive surgical treatment for multiple axis fractures.CASE SUMMARY We report a 40-year-old Chinese male who had severe neck pain and difficult neck movement after falling from 3 meters. X-ray and computed tomography(CT) scan revealed an axis injury consisting of an odontoid Type Ⅲ fracture associated with a Hangman fracture categorized as a Levine-Edwards Type Ⅰ fracture. The patient underwent anterior odontoid screw fixation and posterior percutaneous screw fixation using intraoperative O-arm navigation. Neck pain was markedly improved after surgery. X-rays and CT scan reconstructions of 3-mo follow-up showed good stability and fusion. The range of cervical motion was well preserved.CONCLUSION Anterior odontoid screw fixation and posterior direct C2 percutaneous pedicle screw fixation with the aid of O-arm navigation and neurophysiological monitoring can be an interesting alternative option for complicated multiple axis fractures.