Safety study of navigation-assisted medial "in-out-in" technique in C2 screw fixation

To investigate the early effectiveness of transiliac-transsacral screws internal fixation assisted by augmented reality navigation system HoloSight (hereinafter referred to as "computer navigation system") in the treatment of posterior pelvic ring injuries. A retrospective analysis was made in the 41 patients with posterior pelvic ring injuries who had been treated surgically with transiliac-transsacral screws between June 2022 and June 2023. The patients were divided into navigation group (18 cases, using computer navigation system to assist screw implantation) and freehand group (23 cases, using C-arm X-ray fluoroscopy to guide screw implantation) according to the different methods of transiliac-transsacral screws placement. There was no significant difference in gender, age, body mass index, causes of injuries, Tile classification of pelvic fracture, days from injury to operation, usage of unlocking closed reduction technique between the two groups ( P>0.05). The time of screw implantation, the fluoroscopy times, the guide wire adjustment times of each screw, and the incidence of complications were recorded and compared between the two groups. The position of the transiliac-transsacral screw was scanned by CT within 2 days after operation, and the position of the screw was classified according to Gras standard. The operation was successfully completed in both groups. The time of screw implantation, the fluoroscopy times, and the guide wire adjustment times of each screw in the navigation group were significantly less than those in the freehand group ( P<0.05). There were 2 cases of incision infection in the freehand group, and the incision healed by first intention after active dressing change; there was no screw-related complication in the navigation group during operation and early period after operation; the difference in incidence of complications between the two groups (8.7% vs. 0) was not significant ( P=0.495). According to the Gras standard, the screw position of the navigation group was significantly better than that of the freehand group ( P<0.05). Compared with the traditional freehand method, the computer navigation system assisted transiliac-transsacral screws internal fixation in the treatment of posterior pelvic ring injuries has advantages of improving the accuracy of screw implantation and reducing radiation damage and the time of screw implantation.

To investigate the effectiveness of Holosight robotic navigation-assisted percutaneous cannulated screw fixation for femoral neck fractures. A retrospective analysis was conducted on 65 patients with femoral neck fractures treated with cannulated screw fixation between January 2022 and February 2024. Among them, 31 patients underwent robotic navigation-assisted screw placement (navigation group), while 34 underwent conventional freehand percutaneous screw fixation (freehand group). Baseline characteristics, including age, gender, fracture side, injury mechanism, Garden classification, Pauwels classification, and time from injury to operation, showed no significant differences between the two groups ( P>0.05). The operation time, intraoperative blood loss, fluoroscopy frequency, fracture healing time, and complications were recorded and compared, and hip function was evaluated by Harris score at last follow-up. Postoperative anteroposterior and lateral hip X-ray films were taken to assess screw distribution accuracy, including deviation from the femoral neck axis, inter-screw parallelism, and distance from screws to the femoral neck cortex. No significant difference was observed in operation time between the two groups ( P>0.05). However, the navigation group demonstrated superior outcomes in intraoperative blood loss, fluoroscopy frequency, deviation from the femoral neck axis, inter-screw parallelism, and distance from screws to the femoral neck cortex ( P<0.05). No incision infections or deep vein thrombosis occurred. All patients were followed up 12-18 months (mean, 16 months). In the freehand group, 1 case suffered from cannulated screw dislodgement and nonunion secondary to osteonecrosis of femoral head at 1 year after operation, 1 case suffered from screw penetration secondary to osteonecrosis of femoral head at 5 months after operation; and 1 case suffered from nonunion secondary to osteonecrosis of femoral head at 6 months after operation in the navigation group. All the 3 patients underwent internal fixators removal and total hip arthroplasty. There was no significant difference in the incidence of complications between the two groups ( P>0.05). The fracture healing time and hip Harris score at last follow-up in the navigation group were significantly better than those in the freehand group ( P<0.05). Compared to freehand percutaneous screw fixation, Holosight robotic navigation-assisted cannulated screw fixation for femoral neck fractures achieves higher precision, reduced intraoperative radiation exposure, smaller incisions, and superior postoperative hip function recovery.

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

C2 pedicle screw insertion assisted by mobilization of the vertebral artery in cases with high-riding vertebral artery

Objective To explore the role of neuronavigation in emergency surgical rescue for traumatic neurological disease. Methods Sixty-eight patients received surgical treatment for critical neurological disease between May 2016 and March 2017 were included and divided into navigation group and freehand group. Their general information, category of neurological emergency, radiologic characteristics, duration of ICU and hospital stay, perioperative GCS score and prognostic GOS score were retrospectively analyzed. Results These 68 patients (39 males and 29 females) ranged from 19 to 71 years old. The surgery duration and the average length of ICU stay in navigation group (n=16) was shorter than that in freehand group (n=52), but there was no significant difference between the 2 groups. Preoperative GCS score of navigation group was higher than freehand group and there were significant statistic difference (P=0.046) between the two groups with (9.7±4.1) in navigation group and (7.3±3.5) in freehand group. However, the three-month GOS score was not of significant difference between the two groups. The rate of optimal accuracy of the ventricular draining tube was 83.3% in navigation group and 64.3% in freehand group. Conclusion Neuronavigation-assisted minimally invasive operation may be of help to increase the accuracy of lesion localization and ventricular penetration, and may lead to a decrease in surgery duration, especially in the cases of ventricular narrowing and hematoma in deep brain region. Key words: Neuronavigation; Neurotarmatic; Emergency rescue; Minimally invasive surgery

To investigate the effectiveness of HoloSight Orthopaedic Trauma Surgery Robot-assisted infra-acetabular screw placement for treatment of acetabular fractures. The clinical data of 23 patients with acetabular fractures treated with open reduction and internal fixation and infra-acetabular screw placement in two medical centers between June 2022 and October 2023 were retrospectively analyzed. According to the the method of infra-acetabular screw placement, the patients were divided into navigation group (10 cases, using HoloSight Orthopaedic Trauma Surgery Robot-assisted screw placement) and freehand group (13 cases, using traditional X-ray fluoroscopy to guide screw placement). There was no significant difference in gender, age, body mass index, cause of injury, time from injury to operation, and Judet-Letournel classification between the two groups ( P>0.05). The time of infra-acetabular screw placement, the fluoroscopy frequency, the guide pin adjustment times, the quality of screw placement, the quality of fracture reduction, and the function of hip joint were compared between the two groups. All patients completed the operation successfully. The time of screw placement, the fluoroscopy frequency, and guide pin adjustment times in the navigation group were significantly less than those in the freehand group ( P<0.05). The quality of screw placement in the navigation group was significantly better than that in the freehand group ( P<0.05). Patients in both groups were followed up 6-11 months, with an average of 7.7 months. There were 9 and 9 cases in the navigation group and the freehand group who achieved excellent and good fracture reduction quality at 1 week after operation, and 12 and 12 cases with excellent and good hip joint function at last follow-up, respectively, and there was no significant difference between the two groups ( P>0.05). The fractures in both groups healed well, and there was no significant difference in healing time ( P>0.05). During the follow-up, there was no complication related to screw placement, such as failure of internal fixation, vascular and nerve injury, incisional hernia. In the treatment of acetabular fractures, compared with the traditional freehand screw placement, the HoloSight Orthopaedic Trauma Surgery Robot-assisted screw placement can reduce the time of screw placement, improve the accuracy of screw placement, and reduce the amount of radiation, which is an efficient, accurate, and safe surgical method.

The accuracy of robot-assisted pedicle screw implantation is a safe and effective method in lumbar surgery, but it still remains controversial in lumbar revision surgery. This study evaluated the clinical safety and accuracy of robot-assisted versus freehand pedicle screw implantation in lumbar revision surgery. This was a retrospective study. From January 2018 to December 2019, 81 patients underwent posterior lumbar revision surgery in our hospital. Among them, 39 patients underwent revision surgery performed with robot-assisted pedicle screw implantation (Renaissance robotic system), whereas the remaining 42 patients underwent traditional freehand pedicle screw implantation. All patients underwent magnetic resonance imaging (MRI), computed tomography (CT), and X-ray before revision surgery. The sex, age, body mass index, bone mineral density, operative time, blood loss, operative segments, intra-operative fluoroscopy time, and complications were compared between the two groups. The accuracy of pedicle screw implantation was measured on CT scans based on Gertzbein Robbins grading, and the invasion of superior level facet joint was evaluated by Babu's method. There was no statistical difference about the baseline between the two groups (P > 0.05). Although there were no significant differences in operative time and complications between the two groups (P > 0.05), the robot-assisted group had significantly less intra-operative blood loss and shorter intra-operative fluoroscopy times than the freehand group (P < 0.05). In the robot-assisted group, a total of 267 screws were inserted, which were marked as grade A in 250, grade B in 13, grade C in four, and no grade D or E in any screw. In terms of invasion of superior level facet joint, a total of 78 screws were inserted in the robot-assisted group, which were marked as grade 0 in 73, grade 1 in four, grade 2 in one, and grade 3 in zero. By comparison, 288 screws were placed in total in the freehand group, which were rated as grade A in 251, grade B in 28, grade C in eight, grade D in one, and no grade E in any screw. A total of 82 superior level facet joint screws were inserted in freehand group, which were marked as grade 0 in 62, grade onein 18, grade 2 in two, and grade 3 in zero. The robot-assisted technique was statistically superior to the freehand method in the accuracy of screw placement (P < 0.05). Compared with freehand screw implantation, in lumbar revision surgery, the Renaissance robot had higher accuracy and safety of pedicle screw implantation, fewer superior level facet joint violations, and less intra-operative blood loss and intra-operative fluoroscopy time.

Objective To compare the clinical efficacy and fusion rate of unilateral and bilateral C1 and C2 pedicle screw fixation of unstable Jefferson fractures. Methods This retrospective case-control study enrolled 22 patients with unstable Jefferson fractures admitted between April 2012 and May 2015. There were 18 males and four females, with the mean age of 52.9 years (range, 35-67 years). Mean preoperative visual analogue scale (VAS) was 6.09 points (range, 4-8 points). According to the American spinal injury association (ASIA) classification, two patients were rated grade D and one patient grade C. Mean Japanese orthopedic association (JOA) score was 12.3 points. Bilateral C1 and C2 pedicle screw fixation was performed for 15 patients (bilateral group). Advantage side unilateral C1 and C2 pedicle screw fixation was performed for seven patients with extremely unstable fracture or narrow pedicle (unilateral group). Operation time, blood loss and surgical complications were recorded. VAS was used to evaluate the improvement of neck pain after operation. ASIA classification and JOA score were used to assess nerve function recovery. Atlanto-dental interval (ADI), srew position and bone fusion were evaluated after operation. Results All patients successfully completed the operation. Operation time was (119.5±21.2)min, and blood loss was (280.1±83.1)ml. A total of 74 screws were placed and CT scan showed satisfactory position of the screws. No complications were noted either during the operation or after surgery. All patients were followed up for mean 20.7 months (range, 13-33 months). VAS was improved in both groups after operation (P 0.05). Two patients with ASIA grade D in bilateral group were improved to ASIA grade E after operation. One patient with ASIA grade C in unilateral group was improved to ASIA grade D after operation. JOA score increased to mean 15.7 points at last follow-up. ADI were decreased in both groups after operation(P 0.05). All patients had bony fusion 6 months after operation, with similar fusion rate between the two groups (P>0.05). Conclusion Advantage side unilateral screw fixation can be used for the patients with bilateral C1 and C2 pedicle screw fixation failure, for the technique can improve cervical pain and provide relatively high stability and fusion rate. Key words: Atlanto-occipital joint; Spinal fractures; Internal fixators; Spinal fusion

Computer Navigation-Assisted Osteochondroplasty May Improve Accuracy of Resection Planning With Limited Outcome Differences Compared With Freehand Hip Arthroscopic Technique in Patients With Femoroacetabular Impingement Syndrome.

BackgroundThe 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.MethodsWe 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.ResultsOne 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.ConclusionThe O-arm-based navigation exhibits higher accuracy for pedicle screw insertion than the freehand insertion technique.

P105. Intraoperative CT based pedicle screw navigation in pediatric spine deformity increases operative time, radiation exposure with minimal impact on screw accuracy for experienced surgeon

Objective: To examine the feasibility, safety, and efficacy of mobilization of the vertebral artery for C2 pedicle screws in cases with high-riding vertebral artery (HRVA). Methods: The clinical data of 12 patients with basilar invagination and atlantoaxial dislocation underwent atlantoaxial reduction and fixation in the Department of Neurosurgery, the First Affiliated Hospital of University of Science and Technology of China between January 2020 and November 2021 were retrospectively analyzed. All patients had high-riding vertebral artery on at least one side that prohibited the insertion of C2 pedicle screws. There were 2 males and 10 females aged (48.0±12.8) years (range: 17 to 67 years). After correction of vertical dislocation during the operation, the C2 pedicle screw insertion and occipitocervical fixation and fusion were performed using the vertebral artery mobilization technique. Neurological function was assessed using the Japanese Orthopedic Association (JOA) scale. The preoperative and postoperative JOA score and the main radiological measurements, including the anterior atlantodental interval (ADI), the distance of the odontoid tip above the Chamberlain line, the clivus-canal angle, were collected and compared by paired t-test. Results: Mobilization of the high-riding vertebral artery was successfully completed, and C2 pedicle screws were then fulfilled after the vertebral artery was protected. There was no injury to the vertebral artery during the operation. Meanwhile, no severe surgical complications such as cerebral infarction or aggravated neurological dysfunction occurred during the perioperative period. Satisfactory C2 pedicle screw placement and reduction were achieved in all 12 patients. All patients achieved bone fusion 6 months after surgery. No looseness and shift in internal fixation or reduction loss was observed during the follow-up period. Compared to the preoperative, the postoperative ADI decreased from (6.1±1.9) mm to (2.0±1.2) mm (t=6.73, P<0.01), the distance of the odontoid tip above Chamberlain line decreased from (10.4±2.5) mm to (5.5±2.3) mm (t=7.12, P<0.01), the clivus-canal angle increased from (123.4±11.1) ° to (134.7±9.6) ° (t=2.50, P=0.032), the JOA score increased from 13.3±2.1 to 15.6±1.2 (t=6.99, P<0.01). Conclusion: The C2 pedicle screw insertion assisted by mobilization of the vertebral artery is safe and considerably effective, providing a choice for internal fixation in cases with high-riding vertebral arteries.

ObjectiveTo evaluate the accuracy and clinical effect of immediate implant placement(IIP) using real-time dynamic navigation in the posterior maxilla with alveolar bone defects.MethodsA total of 55 patients with 72 implants placed in the posterior maxillary region with alveolar bone defects were retrospectively analyzed between January 1, 2021, and October 31, 2024. The study was divided into two groups, navigation group and freehand implant group.The preoperative planning implant data and postoperative CBCT data of the actual implant were imported into the dynamic navigation accuracy verification software, and the deviations of the actual implant neck, root, depth and angle were calculated and reported. Clinical indicators including implant deviation, initial stability, implant success were recorded.ResultsThere were 38 implants in the navigation group and 34 in the freehand group. All implants were successfully placed without serious complications such as perforation of the maxillary sinus mucosa. The initial stability of the implant in the navigation group was (28.53 ± 5.81)N.cm and (18.47 ± 3.64)N.cm, respectively. The initial stability of the implant in the navigation group was higher than that in the free hand group (P < 0.05). The deviations in the cervical, root, depth, and angulation of the navigation group were all significantly smaller than those of the free-hand implant group, with statistically significant differences (P < 0.05). The median follow-up was 29.6 ± 11.2 months and the implant success rate was 100%.ConclusionsImmediate implant placement in the maxillary posterior region with bone deficiency assisted by real-time dynamic navigation can achieve good implant accuracy and satisfactory clinical results.Clinical relevanceDynamic navigation is an advantage for the IIP of an alveolar bone defect in the posterior region of the maxilla.

Objective To compare the isocentric C-arm 3-dimensional （lso-C 3D） navigation versus conventional C-arm fluoroscopy in terms of accuracy of placing CI lateral mass and C2 pedicle （C1LM-C2P） screws in the treatment of atlantoaxial instability. Methods Thirty patients with atlantoaxial instability were treated with fixation with CI I,M-C2P screws in our hospital from June 2006 to June 201 I. They were 16 men and 14 women, aged frnm 39 to 52 years （average, 45.6 years）. The Iso-C 3D navigation group had 14 patients and there were 16 patients in the conventional fluoroscopy group. The 2 groups were comparable in general clinical data （ P 〉 0.05） . The operation time, radiation time, intraoperative blood loss, insertion accuracy and Japanese Orthopaedic Association （JOA） score were recorded and compared between the 2 groups. Results There were no significant differences between the 2 groups in the mean operation time （132. 1 ±6.4 minutes versus 143.2 ±8.2 minutes） （ t = 1. 761, P =0. 093） . The mean radiation time for the lso-C 3D navigation group （46.8 ± 1.4 seconds） was significantly shorter than for the conventional fluo- roscopy group （65.2±2.9 seeomts）, the mean blood loss for the navigation group （305.6 ±50.8 mL） was significantly less than for the fluoroscopy group （472.4± 56. 1 mL）, the percentage of screws of grade 0 forthe navigation group （94. 6% ） was significantly higher than for the fluoroscopy group （82.8%） （ P 〈 0. 05 ） . The mean follow-up of 12.4 months revealed fracture union on cervical X-ray films 6 months post- operation. There were no significant differences between the 2 groups in the mean JOA score 6 months post- operation （15.2± 0. 2 points versus 15.3 ± 0. 3 points）, but there were significant differences between the preoperative and postoperative scores in the 2 groups （ P 〈 0.05）. Conclusion In the treatment of at- lantoaxial instability with fixation with C1LM-C2P screws, compared with conventional C-ann fluoroscopy, Iso-C 3D navigation can significantly improve the accuracy of screw placement and reduce intraoperative flu- oroscopic time and blood loss. Key words: Atlas; Axis; Surgery, computer-assisted; Bone nail

A retrospective study. The aim of the study was to compare the precision of C1 lateral mass and C2 pedicle (C1LM-C2P) screw fixation for atlantoaxial instability using the isocentric C-arm 3-dimensional (Iso-C 3D) navigation versus conventional fluoroscopy. The Iso-C 3D navigation has been widely used in spinal surgeries in recent years. The advantages of this navigation system compared with conventional fluoroscopy in C1LM-C2P screw fixation for atlantoaxial instability are not known. Twenty-four patients diagnosed with atlantoaxial instability were treated with C1LM-C2P screw fixation in this study. The navigation group included 12 patients and the other 12 patients were in the conventional fluoroscopy group. The clinical and radiographic results were recorded and compared between the 2 groups. Patients were followed up with clinical examination and radiographs at a mean of 10.8 months. There were no significant differences between groups in the mean age, gender, and causes of atlantoaxial instability. Operative time was 130 ± 5.4 minutes in the navigation group versus 145 ± 6.5 minutes in the conventional fluoroscopy group. The mean blood loss in the navigation group was 304.2 ± 47.9 mL relative to 462.5 ± 55.4 mL in the conventional fluoroscopy group. The radiation time was significantly reduced using 3D navigation (47.5 ± 1.5 s vs. 64.0 ± 3.0 s). 95.8% (46/48) of 3D navigated screws and 83.3% (40/48) of fluoroscopy screws had no pedicle perforation. Each patient showed evidence of solid fusion after 6 months on cervical plain radiographies. On comparing the 2 imaging techniques, it was found that using Iso-C 3D navigation can significantly improve the accuracy of screw placement and decrease intraoperative fluoroscopic time and blood loss. This study demonstrates that Iso-C 3D navigation is a safe and effective means of guiding C1LM-C2P screw fixation for atlantoaxial instability.