Accuracy of dental implants positioning in computer-assisted surgeries: In vitro study.

OBJECTIVES: The aim of this study is to presents an experimental method for surgical guide confection using an intraoral scanner to obtain a 3D model of the patient's complete denture and compare its accuracy with the conventional methodology using computed tomography. STUDY DESIGN: This prospective in-vitro study used 30 polyurethane pre-manufactured mandibles which were divided into two groups, conventional technique (group I) and a new method using intraoral scanner (group II), establishing the virtually planned position of the dental implants as a control group, considered as the gold standard for postoperative comparison. RESULTS: The difference between these methods is close to zero and not statistically significant (p > 0.05), being heigh deviation (Xh) with p:0.130 and angulation difference of dental implants between the groups (Ang) with p:0.396. CONCLUSION: The acquisition of stereolithography image of the prosthesis using an intraoral scanner has a clinically acceptable accuracy, being in agreement with the conventional method.

Biochemical implications of robotic surgery: a new frontier in the operating room.

Robotic surgery represents a milestone in surgical procedures, offering advantages such as less invasive methods, elimination of tremors, scaled motion, and 3D visualization. This in-depth analysis explores the complex biochemical effects of robotic methods. The use of pneumoperitoneum and steep Trendelenburg positioning can decrease pulmonary compliance and splanchnic perfusion while increasing hypercarbia. However, robotic surgery reduces surgical stress and inflammation by minimizing tissue trauma. This contributes to faster recovery but may limit immune function. Robotic procedures also limit ischemia-reperfusion injury and oxidative damage compared to open surgery. They also help preserve native antioxidant defenses and coagulation. In a clinical setting, robotic procedures reduce blood loss, pain, complications, and length of stay compared to traditional procedures. However, risks remain, including device failure, the need for conversion to open surgery and increased costs. On the oncology side, there is still debate about margins, recurrence, and long-term survival. The advent of advanced technologies, such as intraoperative biosensors, localized drug delivery systems, and the incorporation of artificial intelligence, may further improve the efficiency of robotic surgery. However, ethical dilemmas regarding patient consent, privacy, access, and regulation of this disruptive innovation need to be addressed. Overall, this review sheds light on the complex biochemical implications of robotic surgery and highlights areas that require additional mechanistic investigation. It presents a comprehensive approach to responsibly maximize the potential of robotic surgery to improve patient outcomes, integrating technical skill with careful consideration of physiological and ethical issues.

Poor usability of computer-assisted navigation for hip fracture surgery.

INTRODUCTION: The STRYKER ADAPT computer-assisted navigation system provides intraoperative feedback to the surgeon regarding implant placement of the Gamma3 nail. The usability of the ADAPT system has not been evaluated. The aim of the study was to investigate the perceived usability of the ADAPT system. MATERIALS AND METHODS: This was a descriptive study with prospectively collected data. ADAPT was introduced at Aarhus University Hospital in February 2021. Prior to introduction, surgeons at the department attended a general introduction to the system. ADAPT was introduced to the surgical nurses and was on display at the surgical ward at more than one occasion, where personal introduction to the system was possible. After introduction, it was mandatory to use ADAPT when using the Gamma3 nail to treat intertrochanteric femur fractures. After each procedure, primary and an eventual supervisor answered a questionnaire, which encompassed the System Usability Scale (SUS) questionnaire. The SUS is a ten-item questionnaire regarding the perceived usability of a system. SUS scores were translated to adjectives, describing user experience on a 7-point adjective scale (worst imaginable, awful, poor, ok, good, excellent, best imaginable). User acceptability, defined as "not acceptable", "marginal" or "acceptable", was also used to interpret the SUS scores. RESULTS: ADAPT was used in 50 procedures by 29 different surgeons, with varying skill-level. Median SUS-score after first-time use of ADAPT for all 29 surgeons was 43 (range: 5-60), which translated to "poor" or "not acceptable". For surgeons who performed ≥ 3 ADAPT-assisted procedures, there were no statistically significant difference in their first to latest SUS-score (median difference: 4.3, p = 0.5). In free text comments ADAPT was positively described as helpful in placement of K-wire and providing educational opportunities for inexperienced surgeons and negatively as inconsistent, slow, time consuming, and causing excessive fluoroscopy. CONCLUSIONS: Usability and acceptability of ADAPT was rated as "poor" or "not acceptable" by the majority of operating surgeons. ADAPT has not been used at our institution based on these findings. The System Usability Scale may be used in further research exploring usability and acceptability of novel computer-assisted navigation systems for orthopaedic surgery.

Accuracy of surgical navigation for patient-specific reconstructions of orbital fractures: A systematic review and meta-analysis.

OBJECTIVE: This systematic review and meta-analysis aimed to review the recent literature on the technical accuracy of surgical navigation for patient-specific reconstruction of orbital fractures using a patient-specific implant, and to compare surgical navigation with conventional techniques. MATERIALS AND METHODS: A systematic literature search was conducted in PubMed (Medline), Embase, Web of Science, and Cochrane (Core Collection) databases on May 16, 2023. Literature comparing surgical navigation with a conventional method using postoperative three-dimensional computed tomography imaging was collected. Only articles that studied at least one of the following outcomes were included: technical accuracy (angular accuracy, linear accuracy, volumetric accuracy, and degree of enophthalmos), preoperative and perioperative times, need for revision, complications, and total cost of the intervention. MINORS criteria were used to evaluate the quality of the articles. RESULTS: After screening 3733 articles, 696 patients from 27 studies were included. A meta-analysis was conducted to evaluate volumetric accuracy and revision rates. Meta-analysis proved a significant better volumetric accuracy (0.93 cm3 ± 0.47 cm3) when surgical navigation was used compared with conventional surgery (2.17 cm3 ± 1.35 cm3). No meta-analysis of linear accuracy, angular accuracy, or enophthalmos was possible due to methodological heterogeneity. Surgical navigation had a revision rate of 4.9%, which was significantly lower than that of the conventional surgery (17%). Costs were increased when surgical navigation was used. CONCLUSION: Studies with higher MINORS scores demonstrated enhanced volumetric precision compared with traditional approaches. Surgical navigation has proven effective in reducing revision rates compared to conventional approaches, despite increased costs.

Feasibility of the set-up for the different approaches in robotic head and neck surgery with the Versius Surgical System.

The Versius Surgical System is a next generation soft-tissue robot with instrument and endoscope arms split into individual modules. Despite its similarities with previous systems, the basic changes in the design raise concerns relating to the feasibility of the set-up for the different approaches in robotic head and neck surgery procedures. We used a complete unit with a surgeon's console and four modules on a training mannequin to depict the different configurations in the operating room. We tested transoral robotic surgery and the four basic configurations for the remote access to the neck: transoral/transvestibular, retroauricular, axillary and bilateral axillo-breast approaches. We obtained a high quality simulation for transoral robotic surgery, as well as for the usual remote access approaches, except for the axillary approach. We were able to obtain an optimal distribution of the modules around the surgical table and an adequate configuration of the joints allowing the instruments to reach their targets. The Versius Surgical System might be an alternative device for robotic procedures in head and neck surgery, although this needs to be proved in a clinical setting.

A learning curve in 3D virtual surgical planned orthognathic surgery.

OBJECTIVES: To assess the surgical accuracy of 3D virtual surgical planned orthognathic surgery and the influence of posterior impaction and magnitude of the planned movements on a possible learning curve. MATERIALS AND METHODS: This prospective cohort study included subjects who underwent bimaxillary surgery between 2016 and 2020 at the Department of Oral and Maxillofacial Surgery of the Radboud University Medical Center, Nijmegen. 3D virtual surgical planning (VSP) was performed with CBCT data and digitalized dentition data. By using voxel-based matching with pre- and postoperative CBCT data the maxillary movements were quantified in six degrees of freedom. The primary outcome variable, surgical accuracy, was defined as the difference between the planned and achieved maxillary movement. RESULTS: Based on 124 subjects, the surgical accuracy increased annually from 2016 to 2020 in terms of vertical translations (0.82 ± 0.28 mm; p = 0.038) and yaw rotations (0.68 ± 0.22°; p = 0.028). An increase in surgical accuracy was observed when combining all six degrees of freedom (p = 0.021) and specifically between 2016 and 2020 (p = 0.004). An unfavorable learning curve was seen with posterior impaction and with a greater magnitude of movements. CONCLUSION: The present study demonstrated a significant increase in surgical accuracy annually and therefore supports the presence of a learning curve. CLINICAL RELEVANCE: Cases with planned maxillary posterior impaction and/or a great magnitude of jaw movements should be transferred from the 3D VSP with extra care to obtain a satisfactory surgical accuracy.

Low-cost and open-source three-dimensional (3D) printing in neurosurgery: A pilot experiment using direct drive modification to produce multi-material neuroanatomical models.

BACKGROUND: 3-dimensional (3D) printing carries a genuine potential for pre-operative planning in neurosurgery. Entry-level 3D printers offer practicality in low resource settings, but are often limited by the range of filament materials as well as the capability of open-source segmentation software. OBJECTIVE: We intended to demonstrate that 3D printing of neuroanatomical structures is possible using an entry-level 3D printer equipped with the direct drive (DD) modification, which supported flexible filaments, with the models segmented using an open-source software. METHODS: A DD system was installed onto the Ender 3 Pro printer. An attempt to print neurosurgical models using a low-cost 3D printer was conducted, where four patient-based neuroanatomical models were printed: skull base-vasculature, skull base-tumour, cervical spine, and ventricular system. The results were discussed and compared to similar endeavours in past literature. RESULTS: Although DD installation was challenging and led to vibration and longer print time, which ultimately warranted an inferior printing speed, DD system enabled the printing with thermoplastic polyurethane (TPU), a versatile elastomer; in addition to producing equal amount of detail to those printed with high-end printers and advanced image segmentation software. Fitting the frame well, changing infill type, and avoiding warping and stringing will improve print quality with the DD system. CONCLUSION: 3D printing with entry-level 3D printers equipped with DD system has been proven to be a reliable way of accurately reproducing patient-specific neuroanatomical constructs. Follow-up studies are necessary to implement 3D printing for neurosurgical planning in low-resource settings.

[Imaging examination procedures, navigation and minimally invasive procedures in acetabular surgery]. / Bildgebende Untersuchungsverfahren, Navigation und minimal-invasive Verfahren in der Acetabulumchirurgie.

Acetabular fractures still pose a special challenge even today. Considering the increasing case numbers, especially in the geriatric patient group, modern imaging examination procedures represent an essential pillar of the diagnostics. Especially in this vulnerable patient group, minimally invasive methods are necessary, which can be guaranteed by intraoperative navigation; however, the choice of surgical access and implants is also made based on the existing morphological characteristics of fractures, which highlights the importance of an imaging modality that is as detailed as possible. Last but not least, new developments concerning the surgical treatment of these injuries are also based on this. This article summarizes the current state of the techniques and the available literature.

Minimal invasiveness at dental implant placement: A systematic review with meta-analyses on flapless fully guided surgery.

Flapless and fully guided implant placement has the potential to maximize efficacy outcomes and at the same time to minimize surgical invasiveness. The aim of the current systematic review was to answer the following PICO question: "In adult human subjects undergoing dental implant placement (P), is minimally invasive flapless computer-aided fully guided (either dynamic or static computer-aided implant placement (sCAIP)) (I) superior to flapped conventional (free-handed implant placement (FHIP) or cast-based/drill partially guided implant placement (dPGIP)) surgery (C), in terms of efficacy, patient morbidity, long-term prognosis, and costs (O)?" Randomized clinical trials (RCTs) fulfilling specific inclusion criteria established to answer the PICO question were included. Two review authors independently searched for eligible studies, screened the titles and abstracts, performed full-text analysis, extracted the data from the published reports, and performed the risk of bias assessment. In cases of disagreement, a third review author took the final decision during ad hoc consensus meetings. The study results were summarized using random effects meta-analyses, which were based (wherever possible) on individual patient data (IPD). A total of 10 manuscripts reporting on five RCTs, involving a total of 124 participants and 449 implants, and comparing flapless sCAIP with flapped FHIP/cast-based partially guided implant placement (cPGIP), were included. There was no RCT analyzing flapless dynamic computer-aided implant placement (dCAIP) or flapped dPGIP. Intergroup meta-analyses indicated less depth deviation (difference in means (MD) = -0.28 mm; 95% confidence interval (CI): -0.59 to 0.03; moderate certainty), angular deviation (MD = -3.88 degrees; 95% CI: -7.00 to -0.77; high certainty), coronal (MD = -0.6 mm; 95% CI: -1.21 to 0.01; low certainty) and apical (MD = -0.75 mm; 95% CI: -1.43 to -0.07; moderate certainty) three-dimensional bodily deviations, postoperative pain (MD = -17.09 mm on the visual analogue scale (VAS); 95% CI: -33.38 to -0.80; low certainty), postoperative swelling (MD = -6.59 mm on the VAS; 95% CI: -19.03 to 5.85; very low certainty), intraoperative discomfort (MD = -9.36 mm on the VAS; 95% CI: -17.10 to -1.61) and surgery duration (MD = -24.28 minutes; 95% CI: -28.62 to -19.95) in flapless sCAIP than in flapped FHIP/cPGIP. Despite being more accurate than flapped FHIP/cPGIP, flapless sCAIP still resulted in deviations with respect to the planned position (intragroup meta-analytic means: 0.76 mm in depth, 2.57 degrees in angular, 1.43 mm in coronal, and 1.68 in apical three-dimensional bodily position). Moreover, flapless sCAIP presented a 12% group-specific intraoperative complication rate, resulting in an inability to place the implant with this protocol in 7% of cases. Evidence regarding more clinically relevant outcomes of efficacy (implant survival and success, prosthetically and biologically correct positioning), long-term prognosis, and costs, is currently scarce. When the objective is to guarantee minimal invasiveness at implant placement, clinicians could consider the use of flapless sCAIP. A proper case selection and consideration of a safety margin are, however, suggested.

Navigation-assisted valgus stress method can avoid over correction of high tibial osteotomy / 中华骨科杂志

Objective:To explore the role of navigation-assisted valgus stress method in avoiding excessive correction of lower limb mechanical axis after high tibial osteotomy (HTO).Methods:A retrospective study was carried out on osteoarthritis (OA) patients who were treated with HTO for medial compartment pain of knee from January 2020 to March 2022 in the Department of Joint Surgery, Shanghai Changhai Hospital, the First Affiliated Hospital of Naval Medical University. According to the different ways of confirming alignment during operation, they were divided into computer navigation assisted valgus stress HTO group (referred to as navigation group) and traditional rod fluoroscopy HTO group (referred to as traditional group). There were 28 patients in the navigation group, 10 males and 18 females, with age of 54.4±9.1 years (range, 41-73 years) and body mass index of 26.1±3.3 kg/m 2 (range, 19.8-35.2 kg/m 2); There were 30 patients in the traditional group, 13 males and 17 females, aged 56.9±8.5 years (range, 40-70 years), with a body mass index of 25.7±4.0 kg/m 2 (range, 19.2-32.9 kg/m 2). Measuring the mechanical femoral tibial angle (mFTA), joint line convergence angle (JLCA), medial proximal tibial angle (MPTA), Lysholm score and Hospital for Special Surgery (HSS) score before operation and at the last follow-up of the two groups, and conduct statistical analysis. Results:Both groups were followed up. The follow-up time of navigation group and traditional group was 21.3±8.7 months and 22.5±7.6 months, respectively, with no significant difference ( t=0.53, P=0.596). There were significant differences between the two groups in the amount of mechanical axis correction (ΔmFTA) and the amount of bone correction (ΔMPTA) ( t=2.09, P=0.041; t=2.58, P=0.012), while there was no significant difference in ΔJLCA ( t=0.32, P=0.753). In the navigation group, there were 9 cases (32%) of undercorrection, 17 cases (61%) with acceptable alignment, and 2 cases (7%) with over correction, while in the traditional group, there were 5 cases (17%) with under correction, 13 cases (43%) with acceptable alignment, and 12 cases (40%) with over correction. There was significant difference in the distribution rate of alignment between the two groups ( P=0.012), and the rate of overcorrection in the navigation group was significantly lower than that in the control group (7% vs. 40%, P=0.005). The intra group correlation coefficient between the navigation correction mechanical axis and ΔmFTA was 0.787. There was no significant difference in Lysholm score and HSS score between the two groups before and after surgery (all P>0.05), and they were significantly improved after operation (all P<0.05). Conclusion:Navigation-assisted valgus stress method HTO is reliable, which can accurately achieve the target alignment, reduce the incidence of over correction, and obtain good clinical results.

Application of preoperative three-dimensional reconstruction planning in total hip arthroplasty for development dysplasia of the hip secondary to osteoarthritis / 中华骨科杂志

Objective:To investigate the clinical efficacy of preoperative three-dimensional (3D) reconstruction planning in total hip arthroplasty for development dysplasia of the hip secondary to osteoarthritis.Methods:A total of 80 patients with osteoarthritis secondary to Crowe I-III developmental dysplasia of the hip who underwent primary unilateral total hip arthroplasty from October 2019 to March 2021 were retrospectively analyzed, including 18 males and 62 females and the mean age was 55.7±10.4 years (range 41-72 years). Forty patients in the 3D group, the prosthesis type and installation angle were planed on the 3D reconstruction software based on the full-length CT scan data of the lower limbs, and the length difference of the lower limbs and hip offset were calculated. Forty patients in the control group underwent preoperative planning using conventional film measurement, and lower limb length was judged based on the preoperative measurement data and intraoperative comparison of both lower limbs. The difference of postoperative leg length, hip offset, hip function score, operating time, intraoperative blood loss, and incidence of complications were compared between the two groups.Results:All 80 patients completed the surgery successfully and the follow-up time was up to 3 months after operation. The 3D group was better than the control group in operation time (70.9±7.7 min vs. 81.6±13.3 min, t=-4.91, P<0.001), the difference of postoperative lower limb length (2.78±1.31 cm vs. 5.35±2.15 cm, t=-5.74, P<0.001), and hip function score at 1 week after operation (75.67±3.35 vs. 67.35±4.21, t=12.33, P=0.002), with statistically significant differences. In the 3D group, 95% of acetabular prosthesis and 90% of femoral stem components were consistent with the planned model, while the rate were only 75% and 68% in the control group, and the difference was statistically significant (χ 2=7.51, P=0.023; χ 2=14.92, P=0.005). There were no intraoperative complications such as vascular and nerve injury, and no postoperative complications such as dislocation or periprosthetic infection in all 80 patients. Conclusion:3D preoperative planning assisted total hip arthroplasty in the treatment of Crowe I-III developmental dysplasia of the hip secondary to osteoarthritis can improve the accuracy of the operation, and has a good clinical effect on restoring the leg length and hip offset.

Application of digital technology in the reconstruction of orbital fractures: research progress / 中华创伤杂志

Orbital fracture often leads to facial collapse, diplopia, enophthalmos, and even blindness. Traditional surgery relies on the experiences of physicians to achieve fracture reduction and orbital wall reconstruction, but the repair effect is not satisfactory. In recent years, with the development of digital technology, technologies such as computer-assisted surgery, 3D printing, surgical navigation systems, and intraoperative CT imaging have become increasingly widespread in the field of orbital reconstruction. Such techniques can avoid dependence on physicians′ experiences and make it easy for estimating and positioning the implantation sites, which subsequently contributes to better surgery efficiency and precise reconstruction of the orbit, improving aesthetics and visual function of patients. To this end, the authors reviewed the recent progress in application of digital technology for orbital fracture reconstruction, so as to provide reference and theoretical basis for clinical practice.

Open reduction and internal fixation assisted by computer virtual surgery in the treatment of complex proximal humeral fracture / 中华创伤杂志

Objective:To investigate the effect of open reduction and internal fixation assisted by computer virtual surgery in the treatment of complex proximal humeral fracture.Methods:A retrospective case series study was performed on clinical data of 36 patients with complex proximal humeral fracture admitted to Dongfang Hospital Affiliated to Tongji University from January 2018 to June 2020. There were 13 males and 23 females, aged 22-86 years [(56.4±4.8)years]. They were all closed fractures. According to Neer classification, there were 20 patients with three-part fractures and 16 with four-part fractures. Precise pre-surgical designs made by using the digital orthopedic surgery planning system of the E-3D were applied to assist the implementation of precise fracture reduction and internal fixation with the locking plate. The fracture healing was observed. The effect of the real surgery assisted by the virtual surgical designs was assessed by comparing the humeral neck shaft angle and humeral head height measured at the virtual surgery and at day 1 after the real surgery. The humeral neck shaft angle, humeral head height, shoulder range of motion (abduction, external rotation and forward flexion), Constant shoulder function score and visual analogue score (VAS) were recorded at 1 day, 3 months and 12 months after the real surgery. The stability of the medial column was assessed at 1 day after the real surgery. The complications were recorded.Results:All patients were followed up for 12-38 months [(18.5±1.8)months]. The fracture showed bony union in all patients with the union time of 6.6-17.2 weeks [(10.2±1.0)weeks]. The humeral neck shaft angle and humeral head height showed no significant differences measured at the virtual surgery and at 1 day after the real surgery, and were also not significant different at 1 day, 3 months and 12 months after the real surgery (all P>0.05). At 3 months and 12 months after the real surgery, the shoulder abduction [(119.4±11.8)°, (155.3±13.7)°], external rotation [(37.6±6.3)°, (46.8±7.4)°], forward flexion [ (94.8±10.2)°, (126.9±1.6)°] and Constant function score [(66.8±8.4)points, (82.4±9.6)points] were all higher than those at 1 day after the real surgery [(53.8±4.5)°, (21.6±3.3)°, (44.6±7.8)°, (34.3±6.1)points], while the VAS [(4.1±0.5)points, (1.2±0.2)points] was lower than that at 1 day after the real surgery [(8.3±1.4)points] (all P<0.05). The medial column was stable in 34 patients and unstable in 2 at 1 day after the real surgery. Complications included screw cutting out in the articular surface in 1 patient and humeral head necrosis in 1. Conclusion:Treatment of complex proximal humeral fractures with open reduction and internal fixation assisted by computer virtual surgery is conducive to maintaining reduction effect, promoting shoulder joint function, relieving pain and reducing complications.

GUIDED PERI-IMPLANT AUTOGENOUS SOFT TISSUE GRAFTING: CASE REPORT.

This case report showed the proof-of-concept of a guided free gingival graft around a dental implant. A 65-year-old male presented to replace his 30 and 31. Once the osseointegration of the 2 implants placed by guided surgery has been achieved, a free gingival graft was indicated. The surgical planning of this graft was performed using the Cone Beam Computed Tomography and archs digital scanning already used for implant placement. The greater palatine foramen and gutter were radiologically located to protect their arterial content. Two surgical guides were designed, one for the palatal donor site and one for the recipient site. The first one will serve both as an incision guide and as a post-operative protective plate. The procedure was free of adverse events. At the 1-year recall, the average gain in keratinized tissue width amounted 2.5 mm. This guided surgery could be used in a patient with insufficient amount of keratinized tissue around a posterior implant. For the first time, it makes it possible to anticipate, accelerate and secure the intervention, to improve the practitioner's comfort and potentially the outcomes of free gingival grafts. Further research and clinical are needed to validate this protocol and to assess its long-term impact on peri-implant health.

Navigation in Shoulder Arthroplasty Surgery.

The indication of shoulder arthroplasties has increased progressively. Accurate positioning of the components may have significant implications for clinical results. The navigation used to aid in the performance of anatomical and reverse total arthroplasties has provided greater precision in implant placement, especially on the glenoid. The development of the technique, material, and prosthesis design have shown encouraging results and led to a trend toward its expansion. In this way, we estimate a higher survival of the arthroplasties resulting from lower rates of dislocation and early loosening. We aim to describe the current technique and to present the results of the literature with navigation. However, comparative clinical studies with long term follow-up are necessary to prove the efficacy in the final results of total shoulder arthroplasties.

Reliability and accuracy of dynamic navigation for zygomatic implant placement.

OBJECTIVES: To assess the accuracy of a real-time dynamic navigation system applied in zygomatic implant (ZI) surgery and summarize device-related negative events and their management. MATERIAL AND METHODS: Patients who presented with severely maxillary atrophy or maxillary defects and received dynamic navigation-supported ZI surgery were included. The deviations of entry, exit, and angle were measured after image data fusion. A linear mixed-effects model was used. Statistical significance was defined as p < .05. Device-related negative events and their management were also recorded and analyzed. RESULTS: Two hundred and thirty-one zygomatic implants (ZIs) with navigation-guided placement were planned in 74 consecutive patients between Jan 2015 and Aug 2020. Among them, 71 patients with 221 ZIs received navigation-guided surgery finally. The deviations in entry, exit, and angle were 1.57 ± 0.71 mm, 2.1 ± 0.94 mm and 2.68 ± 1.25 degrees, respectively. Significant differences were found in entry and exit deviation according to the number of ZIs in the zygomata (p = .03 and .00, respectively). Patients with atrophic maxillary or maxillary defects showed a significant difference in exit deviation (p = .01). A total of 28 device-related negative events occurred, and one resulted in 2 ZI failures due to implant malposition. The overall survival rate of ZIs was 98.64%, and the mean follow-up time was 24.11 months (Standard Deviation [SD]: 12.62). CONCLUSIONS: The navigation-supported ZI implantation is an accurate and reliable surgical approach. However, relevant technical negative events in the navigation process are worthy of attention.

[3D printing in spinal surgery-Update]. / 3D-Druck in der Wirbelsäulenchirurgie ­ Update.

The technique of 3D printing offers a high potential for further optimization of spinal surgery. This new technology has been published for different areas in the field of spinal surgery, e.g. in preoperative planning, intraoperative use as well as to create patient-specific implants. For example, it has been demonstrated that preoperative 3­dimensional visualization of spinal deformities is helpful in planning procedures. Moreover, insertion of pedicle screws seems to be more accurate when using individualized templates to guide the drill compared to freehand techniques. This review summarizes the current literature dealing with 3D printing in spinal surgery with special consideration of the current applications, the limitations and the future potential.