Computer-assisted Navigation Surgery Research Articles

Patient-reported outcome differences for navigated and robot-assisted total hip arthroplasty frequently do not achieve clinically important differences: a systematic review.

Total hip arthroplasty (THA) using computer-assisted navigation (N-THA) and robot-assisted surgery (RA-THA) has been increasingly adopted to improve implant positioning and offset/leg-length restoration. Whether clinically meaningful differences in patient-reported outcomes (PROMs) compared to conventional THA (C-THA) are achieved with intraoperative technology has not been established. This systematic review aimed to assess whether published relative PROM improvements with technology use in THA achieved minimal clinically important differences (MCIDs). PubMed/MEDLINE/Cochrane Library were systematically reviewed for studies comparing PROMs for primary N-THA or RA-THA with C-THA as the control group. Relative improvement differences between groups were compared to established MCID values. Reported clinical and radiographic differences were assessed. Review of N-THA and RA-THA literature yielded 6 (n = 2580) and 10 (n = 2786) studies, respectively, for analyses. Statistically significant improvements in postoperative PROM scores were reported in 2/6 (33.3%) studies comparing N-THA with C-THA, though only 1 (16.7%) reported clinically significant relative improvements. Statistically significant improvements in postoperative PROMs were reported in 6/10 (60.0%) studies comparing RA-THA and C-THA, though none reported clinically significant relative improvements. Improved radiographic outcomes for N-THA and RA-THA were reported in 83.3% and 70.0% of studies, respectively. Only 1 study reported a significant improvement in revision rates with RA-THA as compared to C-THA. Reported PROM scores in studies comparing N-THA or RA-THA to C-THA often do not achieve clinically significant relative improvements. Future studies reporting PROMs should be interpreted in the context of validated MCID values to accurately establish the clinical impact of intraoperative technology.

Computer-based pre- and intra-operative planning modalities for Total Knee Arthroplasty: A comprehensive review

Introduction Since the introduction of total knee arthroplasty (TKA) into modern medicine, many types of digital pre- and intra-operative planning methods have been introduced. Due to the abundance of planning modalities for TKA, physicians are posed with the challenge of which type to implement into their daily practice. In the current fast-paced and research-driven medical environment it is important to understand the differences between the computer-based pre- and intra-operative planning modalities for TKA. Materials and methods The following databases were searched: MedLine, EMBASE, Web of Science, and the Cochrane Library. All articles were independently reviewed by the two reviewers (DS, ID). The following data were extracted, if available: study ID, country of conduction, type of planning modality or modalities, and the use and explanation of historical and currently employed pre- and intra-operative planning modalities for TKA. Results 39 studies were included into the systematic review. Computer assisted surgery (CAS) represents a surgical concept where computer technology is used for surgical planning. CAS for TKA was introduced in the late 1980s. Subsequently, three different types of CAS were developed to plan TKA. The first type of CAS, computer integrated instruments, also known as CAS navigation, provides a real-time view of anatomy and marked surgical instruments intra-operatively. For the second type of CAS, rapid prototyping, or 3D printing, was derived from CAS technology in which the development of patient specific instrumentation (PSI) for TKA followed. Furthermore, CAS aided the evolution of the third type of CAS for TKA: robotics. Conclusion With a high demand for TKA surgery, the challenge to achieve more accurate alignment, improved prosthesis survival, and improved patient satisfaction rates is a very topical one. Planning modalities for TKA were developed to address this demand. This comprehensive systematic review showed that the monumental development of digital planning modalities for TKA has led to a vast amount of well-researched options that surgeons can choose from and use in daily practice.

What Is the Correlation between Coronal Plane Alignment Measured on Pre- and Postoperative Weight-bearing Radiographs and Intraoperative Navigation When Stress Is Applied to the Knee?

This study examines the correlation between the weight-bearing (WB) long leg radiograph (LLR)-derived hip-knee-ankle angle (HKAA) and intraoperative supine computer-assisted surgery (CAS)-derived HKAA measurements at the beginning and end of total knee arthroplasty (TKA). The primary aim of the study was to determine if WB alignment could be mimicked or inferred based on intraoperative alignment findings. We conducted a prospective analysis from a cohort of 129 TKAs undergoing a CAS TKA at a single center by a single surgeon. The HKAA was recorded using the CAS navigation system immediately postregistration of navigation data and after implantation of the prosthesis. The intraoperative HKAA was recorded in both the supine "resting" position of the knee and also while the knee was manipulated in an effort to replicate the patient's WB alignment. These measurements were compared with the HKAA recorded on pre- and postoperative WB LLRs. There was a strong correlation between the preoperative WB LLR HKAA and the intraoperative preimplant CAS-derived stressed HKAA (R = 0.946). However, there was no correlation between the postoperative WB LLR HKAA and the postimplant insertion HKAA as measured intraoperatively via CAS for either a "resting" or "stressed" position of the operated knee (R = 0.165 and R = 0.041, respectively). Thus, the interpretation of intraoperative alignment data is potentially problematic. Despite technological advances in the development and utilization of computer navigation and robotics in arthroplasty to help obtain the optimal alignment, it would seem apparent from our study that this alignment does not correlate to upright stance postoperatively. Surgeons should apply caution to the strength of assumptions they place on intraoperative coronal plane alignment findings.

Pedicle screw placement accuracy in robot-assisted versus image-guided freehand surgery of thoraco-lumbar spine (ROBARTHRODESE): study protocol for a single-centre randomized controlled trial

BackgroundRobotic spinal surgery may result in better pedicle screw placement accuracy, and reduction in radiation exposure and length of stay, compared to freehand surgery. The purpose of this randomized controlled trial (RCT) is to compare screw placement accuracy of robot-assisted surgery with integrated 3D computer-assisted navigation versus freehand surgery with 2D fluoroscopy for arthrodesis of the thoraco-lumbar spine.MethodsThis is a single-centre evaluator-blinded RCT with a 1:1 allocation ratio. Participants (n = 300) will be randomized into two groups, robot-assisted (Mazor X Stealth Edition) versus freehand, after stratification based on the planned number of pedicle screws needed for surgery. The primary outcome is the proportion of pedicle screws placed with grade A accuracy (Gertzbein-Robbins classification) on postoperative computed tomography images. The secondary outcomes are intervention time, operation room occupancy time, length of stay, estimated blood loss, surgeon’s radiation exposure, screw fracture/loosening, superior-level facet joint violation, complication rate, reoperation rate on the same level or one level above, functional and clinical outcomes (Oswestry Disability Index, pain, Hospital Anxiety and Depression Scale, sensory and motor status) and cost-utility analysis.DiscussionThis RCT will provide insight into whether robot-assisted surgery with the newest generation spinal robot yields better pedicle screw placement accuracy than freehand surgery. Potential benefits of robot-assisted surgery include lower complication and revision rates, shorter length of stay, lower radiation exposure and reduction of economic cost of the overall care.Trial registrationClinicalTrials.gov NCT05553028. Registered on September 23, 2022

Robotic-Assisted and Computer-Assisted Navigation Surgery in the Cervical Spine: Current Experiences, Techniques, and Accuracy

Background: In recent years, the role of robotic-assisted and computer-assisted navigation (RA-CAN) systems has significantly expanded in spine surgery, particularly those performed in the thoracic, lumbar and sacral spine showing higher accuracy in pedicle screw placement and improved surgical efficiency. However, there are few reports on these techniques in the cervical spine. The anatomy of the cervical spine possesses additional challenges such as the close proximity to critical neurovascular structures. Purpose: In this article, we present the existing clinical experience of RA-CAN in the cervical spine and evaluate technical considerations. Cervical spine screw fixation and decompression using RA-CAN are reviewed. Results: This analysis covers various aspects such as techniques, accuracy, and the types of procedures reported in the literature. Recent reports include surgical procedures such as anterior cervical diskectomy and fusion’s, odontoid fracture fixation, C1 lateral mass, C2 pedicle, translaminar, subaxial spine lateral mass, and mid-cervical spine pedicle screw fixation. There is potential for enormous clinical benefit to navigated decompression in cervical CAN procedures also. Future opportunities include further improvements in imaging co-localization, pre-surgical planning software, and mechanization of surgical procedures for instrumentation and decompression. Conclusion: The growth of RA-CAN in spinal surgery has shown significant potential in its application in the cervical spine for fusion procedures as well as decompression. By understanding the potential limitations and techniques reported from early experiences, previous techniques can be improved and provide further benefits for accuracy and less invasive surgery.

The Value of Computer-Assisted Navigation for Glenoid Baseplate Implantation in Reverse Shoulder Arthroplasty: A Systematic Review and Meta-Analysis.

Glenoid baseplate malpositioning during reverse total shoulder arthroplasty can contribute to perimeter impingement, dislocation, and loosening. Despite advances in preoperative planning, conventional instrumentation may lead to considerable inaccuracy in implant positioning unless patient-specific guides are used. Optical navigation has the potential to improve accuracy and precision when implanting a reverse shoulder arthroplasty baseplate. This systematic review aimed to analyze the most recent evidence on the accuracy and precision of glenoid baseplate positioning using intraoperative navigation and its potential impact on component selection and surgical time. We conducted a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. The PubMed, Scopus, and EMBASE databases were queried in July 2022 to identify all studies that compared navigation vs. conventional instrumentation for reverse shoulder arthroplasty. Data of deviation from the planned baseplate version and inclination, the use of standard or augmented glenoid components, and surgical time were extracted. Quantitative analysis from the included publications was performed using the inverse-variance approach and Mantel-Haenszel method. Of the 2,048 records identified in the initial query, only 10 articles met the inclusion and exclusion criteria, comprising 667 shoulders that underwent reverse total shoulder arthroplasty. The pooled mean difference (MD) of the deviation from the planned baseplate position for the clinical studies was -0.44 (95% confidence interval [CI], -3.26; p = 0.76; I2 = 36%) for version and -8.75 (95% CI, -16.83 to -0.68; p = 0.02; I2 = 83%) for inclination, both in favor of navigation. The odds ratio of selecting an augmented glenoid component after preoperative planning and navigation-assisted surgery was 8.09 (95% CI, 3.82-17.14; p < 0.00001; I2 = 60%). The average surgical time was 12 minutes longer in the navigation group (MD 12.46, 95% CI, 5.20-19.72; p = 0.0008; I2 = 71%). Preoperative planning integrated with computer-assisted navigation surgery seems to increase the accuracy and precision of glenoid baseplate inclination compared with the preoperatively planned placement during reverse total shoulder arthroplasty. The surgical time and proportion of augmented glenoid components significantly increase when using navigation. However, the clinical impact of these findings on improving prosthesis longevity, complications, and patient functional outcomes is still unknown. Level III, systematic review and meta-analysis. See Instructions for Authors for a complete description of levels of evidence.

A Cadaveric Feasibility Study of an Automatic Multi-Degrees of Freedom Surgical Robot for Percutaneous Scaphoid Guide Pin Insertion.

Background: Percutaneous fixation of scaphoid fractures need accurate guide pin insertion. The emergence of computer-assisted navigation and robotic surgery may provide a promising solution to this problem. Methods: This study presents the development of an automatic multi-degrees of freedom (DOF) surgical robot with computer-assisted navigation system, focusing on percutaneous scaphoid guide pin insertion. Using this device, along with a 3D fluoroscopy unit, we have conducted an experimental study on 10 cadavers for percutaneous scaphoid guide pin insertion to verify the feasibility and reliability of the system. Results: The mean operative duration was 29.1 (SD 4.3) minutes. The cadavers required no more than two attempts to achieve desired wire placement, with the mean positioning-error being 2.0 (SD 0.3) mm and the mean angle-deviation 3.6 (SD 0.7)°. Throughout the study, a mean of 2.2 full-cycle fluoroscopy attempts was required for each cadaver during surgery, and no preoperative CT scan was needed. Conclusions: The outcomes show that using the automatic surgical robot to perform the percutaneous scaphoid guide pin insertion is feasible and desired results can be achieved.

Technology-assisted anterior cruciate ligament reconstruction improves tunnel placement but leads to no change in clinical outcomes: a systematic review and meta-analysis.

To investigate the effect of technology-assisted Anterior Cruciate Ligament Reconstruction (ACLR) on post-operative clinical outcomes and tunnel placement compared to conventional arthroscopic ACLR. CENTRAL, MEDLINE, and Embase were searched from January 2000 to November 17, 2022. Articles were included if there was intraoperative use of computer-assisted navigation, robotics, diagnostic imaging, computer simulations, or 3D printing (3DP). Two reviewers searched, screened, and evaluated the included studies for data quality. Data were abstracted using descriptive statistics and pooled using relative risk ratios (RR) or mean differences (MD), both with 95% confidence intervals (CI), where appropriate. Eleven studies were included with total 775 patients and majority male participants (70.7%). Ages ranged from 14 to 54years (391 patients) and follow-up ranged from 12 to 60months (775 patients). Subjective International Knee Documentation Committee (IKDC) scores increased in the technology-assisted surgery group (473 patients; P = 0.02; MD 1.97, 95% CI 0.27 to 3.66). There was no difference in objective IKDC scores (447 patients; RR 1.02, 95% CI 0.98 to 1.06), Lysholm scores (199 patients; MD 1.14, 95% CI -1.03 to 3.30) or negative pivot-shift tests (278 patients; RR 1.07, 95% CI 0.97 to 1.18) between the two groups. When using technology-assisted surgery, 6 (351 patients) of 8 (451 patients) studies reported more accurate femoral tunnel placement and 6 (321 patients) of 10 (561 patients) studies reported more accurate tibial tunnel placement in at least one measure. One study (209 patients) demonstrated a significant increase in cost associated with use of computer-assisted navigation (mean 1158€) versus conventional surgery (mean 704€). Of the two studies using 3DP templates, production costs ranging from $10 to $42 USD were cited. There was no difference in adverse events between the two groups. Clinical outcomes do not differ between technology-assisted surgery and conventional surgery. Computer-assisted navigation is more expensive and time consuming while 3DP is inexpensive and does not lead to greater operating times. ACLR tunnels can be more accurately located in radiologically ideal places by using technology, but anatomic placement is still undetermined because of variability and inaccuracy of the evaluation systems utilized. Level III.

Intraoperative Technology Use Improves Accuracy of Functional Safe Zone Targeting in Total Hip Arthroplasty.

Targets of acetabular inclination and anteversion have been suggested based on a patient's spinopelvic mobility. Current methods in total hip arthroplasty (THA) include manual instrumentation, computer-assisted navigation, and robotic-assisted surgery. This study aims to compare the accuracy of these 3 methods in targeting the functional safe zone. This is a prospective multicenter study including a series of 251 consecutive primary posterior THA patients from April 2019 to January 2021. Preoperative lateral standing and sitting spinopelvic radiographs were obtained. Each patient was classified using the Hip-Spine Classification. A functional safe zone plan was determined. Surgeons used their preferred method (manual instrumentation, computer-assisted, or robotic-assisted). Postoperative anteversion and inclination was measured and compared to the preoperative plan. Mean differences between preoperative and postoperative values were calculated. Welch's t-test was used to assess significant between-group differences with P < .05 considered significant. Of the 249 patients, there were 63 manual instrumentation, 68 computer-assisted navigation, and 118 robotic-assisted surgery. Robotic-assisted surgery (rTHA) was significantly more accurate in targeting anteversion (1±2) compared to manual instrumentation (mTHA; 7±6, P < .001) and computer-assisted navigation (cTHA; 6±6, P < .001). rTHA was also significantly more accurate in targeting inclination (1±1) compared to mTHA (8±7, P < .001) and cTHA (6±7, P < .001). Although cTHA had greater accuracy in targeting both inclination and anteversion compared to mTHA, these differences were not statistically significant. Robotic-assisted surgery was more accurate than both computer-assisted navigation and manual instrumentation in targeting the functional safe zone in primary THA. Further research is needed to evaluate the effect of improved accuracy on dislocation rates.

Research progress on comparison of the application effects between personal specific instrumentation and computer-assisted navigation surgery in total knee arthroplasty

To compare the application effects between personal specific instrumentation (PSI) and computer-assisted navigation surgery (CAS) in total knee arthroplasty (TKA). The literature comparing the application effects of PSI and CAS in TKA in recent years was widely consulted, and the difference between PSI-TKA and CAS-TKA in operation time, lower limb alignment, blood loss, and knee function were compared. Compared to CAS-TKA, PSI-TKA simplifies operation procedures and shortens operation time but probably has worse lower limb alignment. It is still controversial in comparison of perioperative blood loss and knee function between two techniques. PSI-TKA and CAS-TKA both have advantages and disadvantages, and their differences need to be confirmed by further high-quality clinical trial.

Computer-Assisted Surgical Navigation for Primary and Metastatic Bone Malignancy of the Pelvis: Current Evidence and Future Directions.

Computer-assisted navigation and robotic surgery have gained popularity in the treatment of pelvic bone malignancies, given the complexity of the bony pelvis, the proximity of numerous vital structures, and the historical challenges of pelvic bone tumor surgery. Initial interest was on enhancing the accuracy in sarcoma resection by improving the quality of surgical margins and decreasing the incidence of local recurrences. Several studies have shown an association between intraoperative navigation and increased incidence of negative margin bone resection, but long-term outcomes of navigation in pelvic bone tumor resection have yet to be established. Historically, mechanical stabilization of pelvic bone metastases has been limited to Harrington-type total hip arthroplasty for disabling periacetabular disease, but more recently, computer-assisted surgery has been employed for minimally invasive percutaneous fixation and stabilization; although still in its incipient stages, this procedure is potentially appealing for treating patients with bone metastases to the pelvis. The authors review the literature on navigation for the treatment of primary and metastatic tumors of the pelvic bone and discuss the best practices and limitations of these techniques.

Periprosthetic Fractures Through Tracking Pin Sites Following Computer Navigated and Robotic Total and Unicompartmental Knee Arthroplasty: A Systematic Review.

Use of computer-assisted navigation (CAN) and robotic-assisted (RA) surgery in total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) both necessitate the use of tracking pins rigidly fixed to the femur and tibia. Although periprosthetic fractures through tracking pin sites are rare, there is a paucity of literature on this potential complication. Therefore, the purpose of this study was to perform a systematic review of the current literature to assess the incidence and clinical outcomes of periprosthetic fractures through tracking pin sites following CAN and RA TKA and UKA. A systematic review was performed following PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines using the PubMed, MEDLINE, and Cochrane databases in April 2020. Studies were assessed for the presence of pin site fractures, fracture characteristics, and clinical outcomes. Seventeen clinical studies (5 case series, 1 cohort study, and 11 case reports) involving 29 pin-related fractures were included for review. The overall incidence ranged from 0.06% to 4.8%. The mean time from index arthroplasty to fracture was 9.5 weeks (range, 0 to 40 weeks). The majority of fractures occurred in the femoral diaphysis (59%). Nineteen fractures (66%) were displaced and 10 (34%) were nondisplaced or occult. The majority of cases were atraumatic in nature or involved minor trauma and were typically preceded by persistent leg pain. A transcortical pin trajectory, large pin diameter (>4 mm), diaphyseal fixation, multiple placement attempts, and the use of non-self-drilling, non-self-tapping pins were the most commonly reported risk factors for pin-related periprosthetic fractures following CAN or RA TKA. Surgeons should maintain a high index of suspicion for pin-related fractures in patients with ongoing leg or thigh pain after CAN or RA TKA in order to avoid fracture displacement and additional morbidity. As CAN and RA TKA have unique complication risks, the debate regarding the value of technology-assisted TKA and its cost-effectiveness continues. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The role of computer-assisted navigation in intramedullary nailing of pertrochanteric fractures: a prospective multicentre comparative study between EBA II standard and EBA NAV nails

Background. Computer-assisted navigation surgery has been gaining increasing importance in several orthopaedic fields in the last decade. However, none of the previous studies has described a navigated system in the intramedullary nailing of pertrochanteric femoral fractures. This prospective comparative study aims to compare, for the first time, a navigated pertrochanteric intramedullary nailing system (EBA NAV) to a traditional cephalo-medullary nail (EBA2). Materials and methods. 100 patients with 31-A1 or 31-A2 pertrochanteric femoral fractures were recruited from January to September 2020. Twenty patients were managed using the EBA-NAV system, whereas 80 patients were treated using a traditional cephalomedullary nail (EBA2) implanted under fluoroscopic guidance. The set-up time of the operating room (ST-OR), surgical time, exposure time to ionising radiation and the dose area product (DAP) were compared in the two groups. Results. Although the ST-OR was longer in patients managed with EBA NAV compared with EBA2 system, shorter surgical time and radiation exposure time was observed during EBA NAV surgery. Furthermore, significant DAP reduction was observed during the EBA NAV procedure. Conclusions. This preliminary study shows that EBA NAV navigated pertrochanteric intramedullary nail allows standardisation of the surgical technique, regardless of the surgeon’s experience, and significantly reduces exposure to ionising radiation, both in terms of time and DAP. EBA NAV could also play a key role in improving the learning curve of residents.

Blood loss in total knee arthroplasty using computer-assisted navigation or 3D-printed patient-specific instruments

Objective: To compare the perioperative blood loss in patients undergoing a total knee arthroplasty (TKA) across three different techniques: computer-assisted navigation surgery (CAS), patient specific instrumentation (PSI) and conventional instrumentation (CI). Methods: Ninety consecutive patients with severe knee osteoarthritis who underwent unilateral primary TKA in Peking University Third Hospital Orthopedics Department from January 2018 to December 2018 were enrolled in this prospective study. The patients were randomly divided into three groups (30 case in each group): CAS-TKA group, PSI-TKA group and CI-TKA group. The study measured intraoperative blood loss, total blood loss, hidden blood loss, decreases of hemoglobin and hematocrit, and the post-TKA blood transfusions in the three groups. One-way ANOVA was used to detect the differences among the cohorts, and LSD was used for the post-hoc test. Results: The overall intraoperative blood loss of all patients was 6 ml (5~8 ml). The mean total blood loss and hidden blood loss in CAS-TKA group, PSI-TKA group and CI-TKA group was (1 147.0±301.8) and (1 140.1±301.9)ml, (1 044.3±454.1) and (1 038.5±454.0)ml, (1 154.0±483.6) and (1 145.3±482.7)ml, respectively; there was no significant differences among the three groups (F=0.639, 0.616, both P>0.05). There were no patients who received allogeneic blood transfusion. There were no significant differences in decrease of hemoglobin and hematocrit among the three groups neither (both P>0.05). Conclusions: Compared with conventional TKA, CAS and PSI does not increase the total blood loss of TKA. However, they both demonstrate a potential benefit in reducing blood loss of TKA.

Computer-assisted surgery navigation of pedicle screw insertion by standardized trainees

Objective: To assess the precision and efficiency computer-assisted surgery navigation of pedicle screw insertion by standardized trainees. Methods: From September 2013 to June 2016, 360 thoracic pedicle screws were inserted into 100 patients by standardized trainees (n = 30). Screws on the left side were inserted by hands (control group), while the other side were inserted under the guidance of computer-assistant navigation system (guided group). The insertion time and volume of blood lost by each screw were retrospectively analyzed. The precision ratio was assessed by computerized tomography (CT) scan after operation. Results: The time consumed in screw insertion was significantly shorter in the guided group than that in the control group. The blood lost volume was lesser in the guided group. Post-operation CT scan revealed higher precision in the guided group than that in the control group. Conclusion: Computer-assistant navigation system facilitates the learning of standardized trainees, and reduces the time-consuming and bleeding in thoracic pedicle screw insertion.

Endoscopic sinus surgery with and without computer assisted navigation: A retrospective study

ObjectiveIn the last years endoscopic sinus surgery (ESS) is improved with the introduction of computer assisted navigation (CAN). In this retrospective study we evaluated the usefulness of CAN in endoscopic sinus surgery and studied its advantages over conventional endoscopic sinus surgery. MethodsWe retrospectively reviewed the records of 96 patients with chronic rhinosinusitis (CRS). 48 patients undergoing endoscopic sinus surgery with surgical navigation (A group) and other 48 without navigation (B group). Data about percentage of complications, olfactory function (Visual Analogue Scale), Sino-nasal Outcomes Test (SNOT-22), Rhinosinusitis Quality of Life (RhinoQoL), recurrence (CT Lund–Mackay score), total nasal resistance (rhinomanometry) and duration of the intervention were collected and analyzed. ResultsA group evidenced a decrease of recurrence rate (p=0.009), a reduction of total nasal resistance (p=0.007), of frontal recess stenosis (p=0.04) and of nasal symptomatology (p=0.008). QoL had a better improvement in group A. Rate of other complications and olfactory function did not show statistically significant differences between the two groups. The average calibration time was approximately 11min in the A group. Total time of surgical procedure does not evidenced statistically significant difference between the two groups (p>0.05) but if it is considered only the time of the surgical intervention, the difference of duration is significant reduced statistically (p<0.05) in CAN surgery. ConclusionComputer assisted navigation in ESS can be useful for the most experienced surgeons, especially in the frontal recess surgery, decreasing the recurrence rate and reducing the total nasal resistance.

Effect of the surgical time and coronalmechanical alignment after total knee arthroplasty using computer navigation system, traditionalor 3D printing patient-specific instruments

Objective: To compare the surgical time and postoperative coronal mechanical axis alignment in patients with osteoarthritis who were treated with three different total knee arthroplasty (TKA) techniques: computer-assisted navigation surgery (CAS), patient specific instrumentation(PSI) and traditional instrumentation. Methods: A total of 96 patients with severe knee osteoarthritis who underwent unilateral primary TKA by the same surgeon were included in this retrospective study.The patients were divided into CAS-TKA group (34 patients), PSI-TKA group (29 patients) and control group (33 patients) based on surgical techniques used in the operations.The surgical time and postoperative coronal mechanical axis alignment were compared between the three groups.One-way ANOVA was used to detect the differences between three groups, and LSD test was used for the post-hoc test. Results: The overall mean surgical time of the patients was (79±16) min.CAS-TKA group had significantly longer surgical time when compared with those in the other two groups [CAS-TKA vs PSI-TKA: (90±10) min vs (80±14) min, LSD-t=3.458, P<0.05; CAS-TKA vs control: (90±10) min vs (66±11) min, LSD-t=8.350, P<0.05; PSI-TKA vs control: (80±14) min vs (66±11) min, LSD-t=4.582, P<0.05]. The overall mean postoperative coronal mechanical alignment varus/valgus deformity was 2.4° and 2.0°, respectively.The overall outliers (varus/valgus>3°) represented 22.9% of cases and were distributed as followed: 11.8% in CAS-TKA group, 27.6% in PSI-TKA group, 30.3% in control group; and no significant differences was found among the three groups (χ(2)=3.771, P=0.151). Conclusions: The use of CAS or PSI in TKA costs a significant longer surgical time.These two techniques results in acceptable postoperative coronal alignment and both demonstrated a potential benefit in reducing outliers when compared with the traditional instruments.

Computer-assisted surgery navigation of pedicle screw insertion by standardized trainees

&lt;p&gt;&lt;strong&gt;Objective:&lt;/strong&gt; To assess the precision and efficiency computer-assisted surgery navigation of pedicle screw insertion by standardized trainees. &lt;strong&gt;Methods&lt;/strong&gt; From September 2013 to June 2016, 360 thoracic pedicle screws were inserted into 100 patients by standardized trainees (n = 30). Screws on the left side were inserted by hands (control group), while the other side were inserted under the guidance of computer-assistant navigation system (guided group). The insertion time and volume of blood lost by each screw were retrospectively analyzed. The precision ratio was assessed by computerized tomography (CT) scan after operation. &lt;strong&gt;Results&lt;/strong&gt; The time consumed in screw insertion was significantly shorter in the guided group than that in the control group. The blood lost volume was lesser in the guided group. Post-operation CT scan revealed higher precision in the guided group than that in the control group.&lt;strong&gt; Conclusion&lt;/strong&gt; Computer-assistant navigation system facilitates the learning of standardized trainees, and reduces the time-consuming and bleeding in thoracic pedicle screw insertion. Orthodontics training is the most important low-grade physician training in the orthopedic department1,2. Due to the complexity of spinal anatomy, professional required and high risk of spinal surgery, thoracic pedicle screw implantation has become a very demanding technique. Furthermore, the spine surgery learning is not conducive to the trainees. Since 2013, our department started to use the computer-assisted three-dimensional navigation technology to guide the implantation of screws3. We found that the computer-assisted navigation technology has greater advantage when compared with the traditional hand-implanted technology.&lt;/p&gt;

Measurement of lower limb alignment: there are within-person differences between weight-bearing and non-weight-bearing measurement modalities

Purpose Previous studies have compared weight-bearing mechanical leg axis (MLA) measurements to non-weight-bearing measurement modalities. Most of these studies compared mean or median values and did not analyse within-person differences between measurements. This study evaluates the within-person agreement of MLA measurements between weight-bearing full-length radiographs (FLR) and non-weight-bearing measurement modalities (computer-assisted surgery (CAS) navigation or MRI).Materials and methodsTwo independent observers measured the MLA on pre- and postoperative weight-bearing FLR in 168 patients. These measurements were compared to non-weight-bearing measurements obtained by CAS navigation or MRI. Absolute differences in individual subjects were calculated to determine the agreement between measurement modalities. Linear regression was used to evaluate the possibility that other independent variables impact the differences in measurements.ResultsA difference was found in preoperative measurements between FLR and CAS navigation (mean of 2.5° with limit of agreement (1.96 SD) of 6.4°), as well as between FLR and MRI measurements (mean of 2.4° with limit of agreement (1.96 SD) of 6.9°). Postoperatively, the mean difference between MLA measured on FLR compared to CAS navigation was 1.5° (limit of agreement (1.96 SD) of 4.6°). Linear regression analysis showed that weight-bearing MLA measurements vary significantly from non-weight-bearing MLA measurements. Differences were more severe in patients with mediolateral instability (p = 0.010), age (p = 0.049) and ≥3° varus or valgus alignment (p = 0.008).ConclusionThe clinical importance of this study lies in the finding that there are within-person differences between weight-bearing and non-weight-bearing measurement modalities. This has implications for preoperative planning, performing total knee arthroplasty (TKA), and clinical follow-up after TKA surgery using CAS navigation or patient-specific instrumentation.Level of evidenceIII.

Comparison of Midterm Outcomes of Minimally Invasive Computer-Assisted vs Minimally Invasive Jig-Based Total Knee Arthroplasty

BackgroundMinimally invasive surgery (MIS) has perceived advantages in the early postoperative stage for total knee arthroplasty (TKA). It is not clear whether the improved radiographic alignment achieved by computer-assisted navigation surgery (CAS) improves midterm clinical outcomes. The aim of this study was to compare patient outcomes of MIS TKA performed with and without CAS after a minimum follow-up of 7 years. MethodsBetween 2007 and 2009, 50 patients underwent CAS and MIS TKA, and 50 patients underwent jig-based MIS TKA in this prospective study. Ninety-six patients were evaluated after a mean follow-up of 7.7 years, and clinical and radiological evaluations were performed. ResultsMidterm results demonstrated that the Knee Society knee score, function score, and range of motion were comparable in the 2 groups. The percentage of patients with the mechanical axis within ±3° of neutral was significantly higher in the CAS group than in the jig-based group (94% vs 79%, respectively; P = .038). No knees had loosening after TKA. However, 1 patient in the CAS group demonstrated late infection 4 years postoperatively. ConclusionCAS did not improve midterm outcomes after MIS TKA compared with jig-based surgery, although CAS reduced outliers in coronal alignment.