Free Hand Research Articles

Free Hand One Stage Correction of Kyphoscoliosis

Background: Scoliosis is a complex musculoskeletal torsional deformity of spine that includes: Lateral curvature in the anterior-posterior plane with a Cobb angle greater than 10 degrees, Angulation in the sagittal plane, or Rotation in the transverse plane. Scoliosis classified into neuromuscular, idiopathic, or congenital. Radiological evaluation is done by plain radiography, computed tomography (CT), and magnetic resonance (MR). We aimed to evaluate patients with idiopathic kyphoscoliosis who underwent a freehand posterior approach for scoliosis correction through transpedicular screws fixation. Setting: Al-Azhar University Hospitals. Subjects and Methods: Study was performed on 12 patients with idiopathic kyphoscoliosis who underwent a freehand posterior approach for scoliosis correction through transpedicular screws fixation in Al-Azhar University Hospitals between 2015 to 2018 & follow up for one year. Results: Early outcome showed improved Cobb’s angle and coronal balance significantly after surgery. Correction is 95% in 2 cases (17%), 80% correction in 8 cases (66%), 60% correction in 2 cases (17%). 2 cases have CSF leakage which improved with conservative treatment. Late follow-up shows improvement of patient deformity and cosmetic appearance to the degree of patient satisfaction occur in 7 cases (58%) associated with high SRS-30 total scores. However, assessment of the pain in comparison to preoperative assessment show improvement of pain in 4 cases (33%), persistent in 4 cases (33%), appear in 4 cases (33%). Conclusion: Freehand one-stage correction management of idiopathic kyphoscoliosis through the posterior approach is a safe and effective for near-total correction of deformity with a good outcome with minimal complications.

Accuracy and safety of free-hand pedicle screw placement in cervical injury patients

Objectives: The purpose of this study was to describe the free hand method of pedicle screw placement without intraoperative imaging monitors and to evaluate the accuracy of the screw placement in quadriplegics patients. Methods: A free hand screw was inserted in the eleven cervical injury patients with quadriplegia. We studied the preoperative pedicle dimension in all the patients and assessed the clinical and radiological outcome and accuracy of the screw placement. Results: A total of 44 screws were inserted in the cervical pedicles of eleven patients. The postoperative images showed that 28 of the 44 screws had perforated the pedicles but none of them had breached the spinal canal. Among them 16 screws were grade 2 and 12 screws were grade 3. All the screws had penetrated the lateral wall. There were no neurovascular complications related to any malpositioned screw and there was no screw loosening or instrumentation failure in the patients. Conclusion: The free hand screw placement without intraoperative image guidance seems to be safe and effective method of fixation. But this technique requires sound knowledge of the cervical anatomy and experience and is useful in the places where navigation system are not available.

Clinical application of 3D-printed patient-specific guide plate combined with computer navigation in acetabular reconstruction following resection of periacetabular tumors.

BackgroundThe precise acetabular reconstruction has historically been a challenging procedure. 3D-printed patient-specific guide (PSG) and computer navigation (CN) technologies have been used to assist acetabular component positioning and pelvic reconstruction. This precise reconstruction approach may translate into clinical benefit.MethodsThe clinical data of 84 patients who underwent periacetabular malignant tumor resection and screw-rod-acetabular cage system reconstruction in our center from January 2013 to December 2020 were retrospectively analyzed. Patients were divided into four groups: free hand (FH) group, PSG group, CN group, and PSG combined with computer navigation (PSG + CN) group. The operation time, intraoperative blood loss, and number of fluoroscopy views were recorded. The oncological prognosis, radiographic measurements of the acetabulum, limb function data, and postoperative complications were compared among groups. And finally, we evaluated the risk factors for mechanical failure of the prosthesis.ResultsThe postoperative X-ray and computed tomography (CT) scan revealed that the vertical offset discrepancy (VOD) between affected side and contralateral side was 8.4±1.9, 5.9±2.2, 4.1±1.3, and 2.4±1.2 mm in each groups; the horizontal offset discrepancy (HOD) was 9.0±1.9, 6.1±2.2, 3.2±1.3, and 2.1±1.2 mm, correspondingly; the abduction angle discrepancy (ABAD) was 8.6°±1.8°, 5.6°±2.0°, 2.5°±1.3°, and 1.8°±0.9°, respectively; the anteversion angle discrepancy (ANAD) was 5.9°±1.6°, 3.6°±1.7°, 2.9°±1.6°, and 1.9°±0.9°, correspondingly. Statistical results show that the PSG + CN group was superior to the FH group and the PSG group in terms of acetabular position and limb function (P<0.05). Body mass index (P=0.040) and resection type (P=0.042) were found to be the high-risk factors for mechanical failure of the prosthesis.ConclusionsPSG + CN has potential advantages in improving the accuracy and safety of acetabular positioning and reconstruction.

A novel guided zygomatic implant surgery system compared to free hand: A human cadaver study on accuracy

Objectives: The aim of this human cadaver study was to compare the accuracy of guided versus free-hand zygomatic implant placement. For the guided implant placement laser sintered titanium templates were used.Methods: Forty zygomatic implants were placed in ten cadavers heads. For each case two implants were inserted using the guided protocol (Ezgoma guide, Noris Medical, Israel) and the related surgical kit and the other two by using a free hand approach. Post-operative computed tomography (CT) scans were carried out to assess the deviations between planned and inserted implants. The accuracy was measured by overlaying the post-operative CT scan (with the final position of the achieved implants) with the pre-operative CT scan (with the planned implants).Results: The difference of the mean between planned and placed zygomatic implants by using surgical guides or free hand were statistically significant for all the variables evaluated: angular deviation (1.19°±0.40° and 4.92°±1.71°, p<0.001), linear distance deviation at coronal point (0.88 mm±0.33 mm and 2.04 mm±0.56 mm, p<0.001), at apical point (0.79 mm±0.23 mm and 3.23 mm±1.43 mm, p<0.001) and at apical depth (0.35 mm±0.25 mm and 1.02 mm±0.61 mm, p<0.001).Conclusions: The proposed guided surgery system exhibited a higher accuracy for all the investigated variables, when compared to the free hand technique.

Geometrical analysis of motion schemes on fencing experts from competition videos.

Geometrical fencing is a scientific approach to fencing pioneered by Camillo Agrippa in the XVIth century which consists of characterizing the geometrical structure of fencing movements. Many geometrical spaces are involved in a duel, which evolve over time according to the skills of the fencers and the game rules. In this article, the concept of motion scheme is introduced as a flexible geometrical structure to represent fencing spaces evolving over time. The method is applied to the video of a duel of the Olympic games 2016. Five main results are presented. First, decisive actions of the duel are deduced from the distance between fencers. Second, footwork is reconstructed from horizontal movements of the feet. Third, a kinematic model is developed and compared with data in the literature. Fourth, the lunge attack is characterized and compared with data in the literature. Fifth, the role of the free hand is studied in the case of protective and balancing gestures. These findings provide rich information on the geometrical structure of fencing movements as well as on the tactical-strategic choices made by the fencers in real competition conditions. Finally, four applications illustrate the scientific value of motion schemes in fencing and other sports.

Percutaneous Robot-Assisted versus Freehand S2 Iliosacral Screw Fixation in Unstable Posterior Pelvic Ring Fracture.

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.

К вопросу о совершенствовании деятельности службы авиационной безопасности в России

Introduction: Aviation Security Service is an independent system that ensures the safety of air passengers and the airport as a whole. It has been given a free hand recently, namely, with the adoption of Federal Law No. 491-FZ Dated December 31, 2017 “On Amending the Aviation Code of the Russian Federation for ensuring aviation security”. Before the enactment, these functions were fulfilled by the police. In its activities, the police used some technical means necessary to identify the objects prohibited in circulation, but after the transfer of such powers to the Aviation Security Service, there was a process of improving and digitalizing technical devices, which contributed to improving the quality of screening air passengers, baggage and airport facilities. In its activities, the Aviation Security Service uses a highly systematic improved safety technology; a huge range of high-tech devices is used to ensure this service. But despite the improvement of technologies in the inspection system, the broadening of powers of the Aviation Security Service, there are also several shortcomings in its activities. Such are the gaps in the regulatory framework both for the Aviation Security Service itself and for interaction with the territorial Departments of Internal Affairs in transport. In addition, there is poor recruitment of personnel and corruption component in this area. Purpose: the purpose of the study is to analyze the features of aviation security in Russia and develop measures to improve the activities of the Aviation Security Service. Research methods: the methodological framework for the study is made up of the general scientific methods of cognition. To ensure the objectivity of the research, the analyzed problem is revealed by the authors as a phenomenon using a systematic approach, which allows us to reveal its mechanism in such a way that the theoretical provisions are used with maximum efficiency in practical activities. Research results and conclusions: the authors highlight the features of the activities of the Aviation Security Service in Russia during inspection measures, and also identify the main security problems at the airports.

Duration, deviation and operator's perception of static computer assisted implant placements by inexperienced clinicians.

This study measured the duration, deviation and operator's perception of implant placement by fully guided (FG), pilot-guided (PG) and freehand (FH) protocols by postgraduate students with minimal implant experience. Twenty postgraduate students participated in the study. Half of them placed single anterior (S-Ant) and single posterior (S-Post) implants, and the other half placed anterior (B-Ant) and posterior (B-Post) implants in a wide edentulous area. The PG placement involved surgical guides that only controlled pilot drilling, whilst the FG placement controlled all the drilling steps and implant placement. The duration of implant placement and the operator's perception (ease of drilling, ease of implant placement and operator's preference) were measured. The deviations of placed implants were quantified by measuring the trueness and angulation deviations in relation to the planned implants. The PG placement was the quickest for inserting implants, followed by FG and FH placements, respectively (p<.05). The location of the implant had influenced the duration of implant placement only for the PG placement. In relation to ease of drilling, ease of implant placement and operator's preference, there was no significant difference amongst the different placement protocols or implant locations. The FG placement was associated with least deviations, followed by PG and FH placements, respectively (p<.05). In the hands of postgraduate students with minimal implant experience, FG and PG placements reduced the implant placement duration in comparison with FH placement. The FG placement was consistently more accurate followed by PG placement.

Effect of knee joint angle on individual hamstrings morphology quantified using free-hand 3D ultrasonography

Exercise responses and injury rates differ between individual hamstrings and this may be linked with their morphology. The aim of this study was to compare muscle length and tendon dimensions between the individual hamstrings at two knee joint angles using free hand three-dimensional ultrasound (3D US). Muscle-tendon length and distal tendon cross-sectional area (CSA), volume, length and echogenicity of biceps femoris long (BFlh) and short (BFsh) head, semimembranosus (SM) and semitendinosus (ST) of 16 individuals were measured using free-hand 3D US at 0° (full extension) and 45° of knee flexion. ST showed the greatest length than all muscles and BFsh the lowest (p < 0.05). No difference was observed between SM and BFlh length (p > 0.05). Of the four muscles, ST tendon was longer, with less volume and CSA but greater echogenicity than the other tendons. In contrast, SM and BFlh showed shorter tendons and lower echogenicity but a greater volume and CSA than ST (p < 0.05). Muscle and tendon lengthened from 45° to 0° knee flexion angle (p < 0.05) but this change was not statistically different between individual hamstrings (p > 0.05). Freehand 3D US indicated that hamstring muscle length and distal tendon dimensions differ between individual hamstrings. All muscles and tendons lengthened as the knee was extended but this change was similar for all individual hamstrings.

Ultrasound-guided abdominal wall infiltration versus freehand technique in anterior cutaneous nerve entrapment syndrome (ACNES): randomized clinical trial.

BackgroundThe optimal technique of abdominal wall infiltration for chronic abdominal wall pain due to anterior cutaneous nerve entrapment syndrome (ACNES) is unknown. The aim of this study was to compare pain reduction after an abdominal wall anaesthetic injection by use of an ultrasound-guided technique (US) or given freehand (FH).MethodsIn this multicentre non-blinded randomized trial, adult patients with ACNES were randomized (1:1) to an US or a FH injection technique. Primary outcome was the proportion of injections achieving a minimum of 50 per cent pain reduction on the Numeric Rating Scale (range 0–10) 15–20 min after abdominal wall infiltration (‘successful response’). Secondary outcomes were treatment efficacy after 6 weeks and 3 months, and the influence of the subcutaneous tissue thickness on treatment outcome.ResultsBetween January 2018 and April 2020, 391 injections (US = 192, FH = 199) were administered in 117 randomized patients (US = 55, FH = 62; 76.0 per cent female, mean age 45 years). The proportion of successful responses did not significantly differ immediately after the injection regimen (US 27.1 per cent versus FH 33.2 per cent; P = 0.19) or after 3 months (US 29.4 per cent versus FH 30.5 per cent; P = 0.90). Success was not determined by subcutaneous tissue thickness.ConclusionPain relief following abdominal wall infiltration by a US or FH technique in ACNES is similar and not influenced by subcutaneous tissue thickness.Registration numberDutch Clinical Trial Register NL8465.

Development of open-source software for free-hand 3D vascular ultrasound: Dialysis fistula application.

The arteriovenous fistula (AVF) is the preferred vascular access for End Stage Renal Disease, having superior patency and lower infection risks than prosthetic graft and catheter access. When AVF dysfunction or delayed maturation does occur, the gold standard for diagnosis is the fistula angiogram (a.k.a. fistulogram). 3D ultrasound is available for obstetrical and other specialized uses, but it is cost prohibitive and has a field of view that is too small to cover the region of interest for the dialysis fistula application. We sought to develop a point of care 3D solution using freehand 2D ultrasound data acquisition. We developed open-source software for 3D image reconstruction and projection of an angiogram-like image of the vascular access using a 2D freehand ultrasound scanner. We evaluated this software by comparing the ultrasound "sono-angiogram" images to fistulogram images in five subjects, using visual inspection and by applying the Percent of Exact Match (PEM) as a statistic test. The sono-angiograms showed identifiable characteristics that matched the fistulogram results in all five subjects. The PEM ranged between 42.8% and 77.0%, with Doppler and grayscale ultrasound data, showing complementary advantages and disadvantages when used for sono-angiogram image construction. Motion from freehand ultrasound acquisition was a significant source of mismatch. 3D image generation is a potential advantage with ultrasound data. While further work is needed to improve the accuracy with free hand scanning, fistulogram-like "sono-angiograms" can be generated using point of care 2D ultrasound. Methods such as these may be able to assist in point-of-care diagnosis in the future. The software is open-source, and importantly, the ultrasound data used are non-proprietary and available from any standard ultrasound machine. The simplicity and accessibility of this approach warrant further study.

Study of θϕ Networks via Zagreb Connection Indices

Graph theory can be used to optimize interconnection network systems. The compatibility of such networks mainly depends on their topology. Topological indices may characterize the topology of such networks. In this work, we studied a symmetric network θϕ formed by ϕ time repetition of the process of joining θ copies of a selected graph Ω in such a way that corresponding vertices of Ω in all the copies are joined with each other by a new edge. The symmetry of θϕ is ensured by the involvement of complete graph Kθ in the construction process. The free hand to choose an initial graph Ω and formation of chemical graphs using θϕΩ enhance its importance as a family of graphs which covers all the pre-defined graphs, along with space for new graphs, possibly formed in this way. We used Zagreb connection indices for the characterization of θϕΩ. These indices have gained worth in the field of chemical graph theory in very small duration due to their predictive power for enthalpy, entropy, and acentric factor. These computations are mathematically novel and assist in topological characterization of θϕΩ to enable its emerging use.

Evaluation of Accuracy in Computer Guided Versus Free Hand Immediate Implant Placement in Fresh Extraction Sockets: a Randomized Controlled Clinical Trial

Background: The aim of this study was to compare between computer guided and free hand immediate implant placement in fresh extraction sockets in terms of accuracy of implant positioning.Methods: This is a randomized controlled clinical study, which used CBCT imaging and flapless surgical technique to place implants in fresh extraction sockets. Accuracy measurements were done using BluSky®1software. A total of 22 patients were recruited according to inclusion and exclusion criteria. Results: The mean values at the implant shoulder for implants inserted using computer surgical guides and those inserted using free hand technique in the mesiodistal direction were 0.69 and 1.43mm, respectively. While in the buccolingual direction they were 0.96 and 1.34mm, respectively. At the implant apex in the mesiodistal direction, they were 1.26 and 2.35mm, respectively. While in the buccolingual direction, they were 1.64 and 1.70mm, respectively. For the angular deviation they were 1.57 and 3.18mm respectively in the mesiodistal direction. Whilein the buccolingual direction were 1.29 and 7.76mm, respectively.Conclusions: Accuracy of computer guided immediate implant insertion surpasses the freehand technique in the buccolingual direction in terms of placing Immediate Implants in fresh extraction sockets in maxillary estheticregion and thus the prosthetic aspect.

Perspective on robotic spine surgery: Who's doing the thinking?

Background: Robotic assisted (RA) spine surgery was developed to reduce the morbidity for misplaced thoracolumbar (TL) pedicle screws (PS) resulting in neurovascular injuries, dural fistulas, and/or visceral/other injuries. RA is gaining the attention of spine surgeons to optimize the placement of TL PSs, and to do this more safely/effectively versus utilizing stereotactic navigation alone, or predominantly free hand (FH) techniques. However, little attention is being focused on whether a significant number of these TL RA instrumented fusions are necessary.Methods: RA spine surgery has been developed to improve the safety, efficacy, and accuracy of minimally invasive TL versus open FH PS placement.Results: Theoretical benefits of RA spine surgery include; enhanced accuracy of screw placement, fewer complications, less radiation exposure, smaller incisions, to minimize blood loss, reduce infection rates, shorten operative times, reduce postoperative recovery periods, and shorten lengths of stay. Cons of RA include; increased cost, increased morbidity with steep learning curves, robotic failures of registration, more soft tissue injuries, lateral skiving of drill guides, displacement of robotic arms impacting accurate PS placement, higher reoperation rates, and potential loss of accuracy with motion versus FH techniques. Notably, insufficient attention has been focused on the necessity for performing many of these TL PS instrumented fusions in the first place.Conclusion: RA spinal surgery is still in its infancy, and comparison of RA versus FH techniques for TL PS placement demonstrates several potential pros, but also multiple cons. Further, more attention must be focused on whether many of these TL PS instrumented procedures are even warranted.

Violation of consolidation of the femur after untimely dynamization of the intramedullary blocking rod

Violation of femoral fracture consolidation after blocking intra­medullary osteosynthesis is a fairly common pathology, and requires the attention of physicians due to its prevalence. There are several reasons for this complication: it is the instabi­lity in the system «bone-implant», and the untimely dynamization of the locking nail. Methods. This article presents a case of fracture violated consolidation after blocking intramedullary osteosynthesis caused a nonunion due to nail failure. Results. Patient was injured on 29.12.2018, as a result of a traffic accident. 01.15.2019, the surgery was performed: closed reduction, blocking intramedullary osteosynthesis of the fracture of the middle shaft of the right thigh, static fixation of the nail. Next visit to the clinic was on 02.01.2020, because of pain in the middle third of the thigh, problems with axial weight-bearing on the right leg, limitation of the flexion in the right knee joint. Control radiographs demonstrated no signs of consolidation of the femoral shaft fracture, and migration of the distal locking screw. 08.01.2020 revision surgical treatment was performed. Given the presence of 5 mutually perpendicular holes in the distal part of the nail, two of them were locked in the anterio-posterior view by the free hand method, the migrated screw in the distal part of the nail was replaced, and the nail was dynamized in the proximal part taking into account its design features. Conclusions. To normalize the consolidation processes in patients with nonunion femoral fractures, bone physiology and the positive effect of autocompression should be considered. The described case demonstrates the necessity for timely dynamization of the blocking nail, which confirms our own observations and literature data. Despite the fact that the dynamization of the nail was performed 1 year after blocking intramedullary osteosynthesis, fracture consolidation occurred 5 months after its implementation. Key words. Femoral fracture, blocked intramedullary osteosynthesis, disorders consolidation, dynamization of the construction.

CT texture analysis in evaluation of thymic tumors and thymic hyperplasia: correlation with the international thymic malignancy interest group (ITMIG) stage and WHO grade.

To evaluate the effectiveness of CT texture analysis (CTTA) in (1) differentiating Thymoma (THY) from thymic hyperplasia (TH) (2) low from high WHO grade, and (3) low from high Masaoka Koga (MK)/International Thymic Malignancy Interest Group (ITMIG) stages. After institute ethical clearance, this cross-sectional study analyzed 26 patients (THY-18, TH-8) who underwent dual energy CT (DECT) and surgery between January 2016 and December 2018. CTTA was performed using TexRad (Feedback Medical Ltd., Cambridge, UK- www.fbkmed.com) by a single observer. Free hand regions of interest (ROIs) were placed over axial sections where there was maximum enhancement and homogeneity. Filtration histogram was used to generate six first-order texture parameters [mean, standard deviation (SD), mean of positive pixels (MPP), entropy, skewness, and kurtosis] at six spatial scaling factors "SSF 0, 2, 3, 4, 5, and 6". Mann-Whitney test was applied among various categories and p value < 0.05 was considered significant. Three-step feature selection was performed to determine the best parameters among each category. The best performing parameters were (1) THY vs TH- Mean at "SSF 0" (AUC: 0.8889) and MPP at "SSF 0" (AUC: 0.8889), (2) Low vs high WHO grade - no parameter showed statistical significance with good AUC, and (3) Low vs high MK/ITMIG stage- SD at "SSF 6" (AUC: 0.8052 and 0.8333 respectively]). CTTA revealed several parameters with excellent diagnostic performance in differentiating thymoma from thymic hyperplasia and MK/ITMIG high vs low stages. CTTA could potentially serve as a non-invasive tool for this stratification. This study has employed texture analysis, a novel radiomics method on DECT scans to determine the best performing parameter and their corresponding cut-off values to differentiate among the above-mentioned categories. These new parameters may help add another layer of confidence to non-invasively stratify and prognosticate patients accurately which was only previously possible with a biopsy.

Guided surgery in implantprosthetic rehabilitation

The prosthetic result as well as the long– term success in implant–prosthetic rehabilitation depends on a series of factors such as: position, number of implants, surgical technique, bone and mucosal offer, and others. Usually, free hand surgery does not allow in all the cases to place implants in best position from the prosthetic and biomechanical point of view. Due to the development of scanning technologies and three–dimensional printing, the planning of final results allows the printing of surgical guides, to ensure the most accurate position of dental implants [1,2]. The comparative analysis of conventional and guided implant placement methods has demonstrated significant advantages in favor of guided surgery. However, with the application of additional maneuvers in the treatment (impression, scanning, planning, template fabrication), a number of disadvantages and errors were observed that may affect both, the treatment and results.

Vitrectome with Integrated LED Illumination: Development and Testing

Abstract Background: In current vitrectomy, the surgeon guides the vitrectome and a rigid fiber light guide with one hand each. It would be desirable to have a free hand for other surgical instruments and maneuvers. Methods: In the feasibility study presented here, a 20 gauge vitrectome is equipped with a miniature white LED that could eliminate the need for the separate light guide and therefore free one hand. The functionality of the system is proved in a ping-pong ball filled with agar and an ex-vivo porcine eye. Results: The brightness of the approach appears to be sufficient without any realistic phototoxic retinal hazard while the functionality of the vitrectome, in combination with the LED, is still given. Conclusion: The combination of a 20 gauge vitrectome with a LED illumination unit was successfully tested. The approach can be transferred to small vitrectomes in the future

Computer guided flapless versus Free hand flap surgery for implants supporting All-on-4 fixed prosthesis in atrophied mandible. One year clinical and radiographical results of a randomized trial.

Aim: The purpose of this study was to evaluate clinical and radiographical outcomes of computer guided flapless versus Free hand flap surgery for implants used to anchor All-on-4 fixed prosthesis in atrophied mandible. Materials and methods: Twelve completely edentulous patients with atrophied mandibular ridges were randomly assigned into two groups Group1 (Free hand flap surgery, control): received 4 implants using the All on four protocol and free hand flap surgery and metal guide. Group2 (computer guided flapless surgery, study): received 4 implants using computer guided flapless surgery and stereolithographic surgical guide. Implants were immediately loaded by acrylic prosthesis then full arch ceramometal fixed prosthesis was used as a final restoration. Plaque Index, Gingival Index, pocket depth, stability of the implants, and crestal bone loss were evaluated at baseline, 3, 6 and 12 months after loading. Results: The survival rate of the implants was 95.8% and 91.7% for group 1 and group 2. For both groups, implant stability significantly decreased from insertion to 3 months, and increased again at six months. For both techniques, crestal bone loss significantly increased with time. For all time intervals, flap group showed significant higher plaque index, gingival index, probing depth and crestal bone resorption than flapless group. Conclusion: Within the limits of this short-term randomized trial regarding the small sample size, computer guided flapless approach may be recommended for all on four implant rehabilitation of edentulous mandibles than conventional flap surgical approach as it was associated with favorable clinical and radiographical peri-implant parameters.

English

BACKGROUND The factors that influence the implant accuracy are the anatomy of the patient, the experience of the practitioner and the surgical approach. However, the relative importance of each factor is poorly understood. Favourable function, occlusion, aesthetics and implant loading patterns can be obtained by optimal positioning. The experience of the surgeon is of utmost importance for the skill of placing a dental implant with proper angulation. The purpose of this retrospective study was to determine the increased accuracy obtained in performing freehand surgical placement of implants. METHODS This study was conducted in the Department of Implantology. A total of 1216 postoperative periapical radiographs from which single implant placement with adjacent straight root morphology was collected from the department in the period of June 2019 to June 2020 and checked for angulation, practitioner’s experience and the site of placement. Mesio-distal angulation was calculated. Statistical analysis was performed using the SPSS method. RESULTS The results showed accuracy in angulation and positioning of implants increased with an increase in experience of the dental surgeon (oral surgeons, prosthodontists, periodontists). Within the limitations of the study, it showed that the freehand dental implant placement angulation was less than a degree for experienced surgeons. The postgraduates had a better understanding and orientation of the angulation than the undergraduates. Moreover, the difficult site was the second and third quadrant to assess the angulation properly. CONCLUSIONS With proper assessment of the anatomy and with experience freehand dental implant placement shows significant results with less angulation which can be prosthetically accepted. KEY WORDS Free Hand Surgery, Guided Surgery, Angulation Of Implants.