Graft Length Research Articles

The effectiveness of acellular nerve allografts compared to autografts in animal models: A systematic review and meta-analysis.

Treatment of nerve injuries proves to be a worldwide clinical challenge. Acellular nerve allografts are suggested to be a promising alternative for bridging a nerve gap to the current gold standard, an autologous nerve graft. To systematically review the efficacy of the acellular nerve allograft, its difference from the gold standard (the nerve autograft) and to discuss its possible indications. PubMed, Embase and Web of Science were systematically searched until the 4th of January 2022. Original peer reviewed paper that presented 1) distinctive data; 2) a clear comparison between not immunologically processed acellular allografts and autologous nerve transfers; 3) was performed in laboratory animals of all species and sex. Meta analyses and subgroup analyses (for graft length and species) were conducted for muscle weight, sciatic function index, ankle angle, nerve conduction velocity, axon count diameter, tetanic contraction and amplitude using a Random effects model. Subgroup analyses were conducted on graft length and species. Fifty articles were included in this review and all were included in the meta-analyses. An acellular allograft resulted in a significantly lower muscle weight, sciatic function index, ankle angle, nerve conduction velocity, axon count and smaller diameter, tetanic contraction compared to an autologous nerve graft. No difference was found in amplitude between acellular allografts and autologous nerve transfers. Post hoc subgroup analyses of graft length showed a significant reduced muscle weight in long grafts versus small and medium length grafts. All included studies showed a large variance in methodological design. Our review shows that the included studies, investigating the use of acellular allografts, showed a large variance in methodological design and are as a consequence difficult to compare. Nevertheless, our results indicate that treating a nerve gap with an allograft results in an inferior nerve recovery compared to an autograft in seven out of eight outcomes assessed in experimental animals. In addition, based on our preliminary post hoc subgroup analyses we suggest that when an allograft is being used an allograft in short and medium (0-1cm, > 1-2cm) nerve gaps is preferred over an allograft in long (> 2cm) nerve gaps.

Efficacy of personalized 3D-printed osteotomy guide in maximizing fibular utilization and minimizing graft length for reconstruction of large mandibular defect.

The study addresses the long-standing challenge of insufficient length in vascularized fibular flaps when reconstructing large mandibular defects that require dual-barrel grafts. Employing personalized 3D-printed osteotomy guides, the study aims to optimize fibular utilization and minimize the required graft length. Two reconstruction methods for distal bone defects were compared: a fold-down (FD) group that employed a specialized osteotomy guide for folding down a triangular bone segment, and a traditional double-barrel (DB) group. Metrics for comparison included defect and graft lengths, as well as the graft-to-defect length ratio. Postoperative quality of life was assessed using the University of Washington Quality of Life questionnaire (UW-QoL). Both FD and DB groups achieved successful mandibular reconstruction. Despite larger defects in the FD group (117 ± 31.35mm vs 84 ± 35.34mm, p = 0.028), the used fibula length was not statistically longer in the FD group. The median ratio of graft-to-defect length was also lower in the FD group (1.327 vs 1.629, p = 0.024), suggesting that FD required only 82.47% of the graft length needed in the DB approach. Quality of life scores post-surgery were comparable between the groups. Personalized 3D-printed osteotomy guides enhance fibula graft efficacy for reconstructing larger mandibular defects, necessitating shorter graft lengths while preserving postoperative quality of life. This study confirms the utility of 3D printing technology as an effective and precise tool in orthopedic surgery, particularly for complex reconstructions like large mandibular defects. It suggests a viable alternative that could potentially revolutionize current practices in bone grafting.

Anatomic Feasibility of a Superficial Temporal Artery to Distal Anterior Cerebral Artery Bypass With a Parietal Branch Interposition Graft: The Superficial Temporal Artery Telescope Bypass.

Revascularizing the postcommunicating segment of the anterior cerebral artery (ACA) using extracranial donor sites requires long interposition grafts. The superficial temporal artery (STA) is frequently used for extracranial-intracranial ACA revascularization. However, the length of either STA branch is not sufficient to reach the ACA with a proper caliber match, so an interposition graft is required. The aim of this study was to evaluate a bypass that uses the 2 main branches of the STA to reach the A3 (pericallosal) segment of the ACA. The frontal and parietal branches of the STA were dissected from 10 cadaveric specimens. The middle internal frontal artery (MIFA) was exposed through an anterior interhemispheric approach. An interposition graft technique was applied using the parietal branch of the STA (pSTA) to connect the frontal branch of the STA (fSTA) with the MIFA. The bypass code is fSTA (E-Ec) pSTA + pSTA (E-Sc) MIFA. Measurements of length and caliber were taken at the anastomotic sites for the distal branches of the STA and the MIFA. The mean (SD) diameter of the MIFA measured 1.4 (0.2) mm, similar to the calibers of the frontal and parietal branches of the STA. The mean (SD) length of the end-to-side STA-MIFA bypass was 145.5 (7.4) mm, and the mean (SD) length of the donor-graft construct measured 204.2 (27.9) mm. This bypass design resulted in a surplus donor graft length of 38%. Using the pSTA as an interposition graft proved to be a successful technique for creating an STA-MIFA bypass, yielding excess donor graft length that facilitated an unstrained bypass construct. This approach offers several advantages, including a single skin incision, ample graft length, caliber compatibility, and a straightforward technical execution.

Minimal-invasive ileal ureter replacement for the management of multiple ureteral polyps: the initial experience.

To present our initial experience in the management of multiple ureteral polyps with robotic or laparoscopic ileal ureter replacement (IUR). Eight consecutive patients diagnosed with multiple ureteral polyps underwent robotic or laparoscopic IUR between July 2019 and November 2022. Unilateral IUR was performed in 5 patients with polyps in the left (n = 3) or right (n = 2) side, and 3 patients with bilateral multiple polyps underwent bilateral IUR. Demographic characteristics, perioperative data and follow-up outcomes were prospectively collected. A cohort of 5 male and 3 female patients (11 ureters) with a mean age of 32.8 ± 11.3 years were included. Among these patients, 5 presented with recurrent flank pain, 1 had hematuria, and 2 were asymptomatic. Four patients experienced prior failed surgical interventions. The mean length of diseased ureter was 11.9 ± 4.7cm, with more than 10cm in eight sides. All procedures were performed successfully. The mean operation time was 319 ± 87.6min with 3 patients who simultaneously underwent intraoperative ureteroscopy. The mean length of ileal graft was 23.8 ± 5.8cm. During the mean follow-up of 20.4 ± 12.8months, one major complication, specifically incision infection, and four minor complications, including urinary infection (n = 3) and metabolic acidosis (n = 1), were observed. All patients presented symptom-free, with improved/stabilized hydronephrosis andno signs of restenosis. Robotic or laparoscopic IUR is a feasible, safe, and effective surgical option for patients with long ureteral defects caused by multiple polyps.

A Novel Predictor of the Length and Size of ACL Grafts in Chinese Han Adults for ACL Reconstruction: An MRI Study.

Currently, there is no simple and valid method to predict the length and size of the native anterior cruciate ligament (ACL) in each adult patient who will undergo ACL reconstruction. This study aimed to develop an imaging prediction method that can predict the length and size of ACL grafts using the intact posterior cruciate ligament (PCL), in order to enhance the graft preparation individualized sizing. Three hundred and nineteen patients aged 18 years or older who underwent magnetic resonance imaging (MRI) of the knee at an orthopaedic clinic between September 9, 2021, and February 5, 2023, were included. The length, sagittal diameter, and coronal diameter of the ACL and PCL were measured in all patients, and F-test were performed to explore linear relationship between ligament measurements. Equations were established to predict a variable of the native ACL for the corresponding variable of the intact PCL (i.e., sagittal diameter of the ACL = 4.32 + 1.08 × sagittal diameter of the PCL, and coronal diameter of the ACL = 2.45 + 0.59 × coronal diameter of the PCL, length of the male ACL = 10.92 + 0.64 × length of the male PCL, length of the female ACL = 11.76 + 0.58 × length of the female PCL) (R2 = 0.532; R2 = 0.417; R2 = 0.488; R2 = 0.509; respectively). The length and size of the intact PCL in cases without PCL buckling are predictors of the length and size of the native ACL in adults, respectively. The use of this information to optimize graft diameter may lower the rates of ACL graft failure in the future.

Determining optimal length of coracoid graft in the modified Bristow procedure for anterior shoulder instability: A three-dimensional finite element analysis.

There is a lack of consensus concerning the coracoid graft length in the modified Bristow procedure. We attempted to determine the optimal graft length using the three-dimensional finite element method. In a shoulder model with a 25% anterior glenoid defect, a coracoid graft of varying lengths (5, 10, 15, and 20 mm) was fixed using a half-threaded screw. First, a compressive load of 500 N was applied to the screw head to determine the graft failure load during screw tightening. Next, a tensile load (200 N) was applied to the graft to determine the failure load due to biceps muscle traction. In the screw compression, the failure loads in the 5-, 10-, 15-, and 20-mm models were 252, 370, 377, and 331 N, respectively. In the tensile load applied to the coracoid graft, the failure load exceeded 200 N for both the 5- and 10-mm models. The 5-mm graft had a high risk of fracture during intraoperative screw tightening. As for the biceps muscle traction, the 5- and 10-mm-grafts had a lower failure risk than the 15- and 20-mm-grafts. Therefore, we believe that the optimal length of the coracoid graft is 10 mm in the modified Bristow procedure.

Distal Radius Allograft for Glenohumeral Instability: A Novel Osteochondral Allograft Reconstruction Option in the Setting of Glenoid Bone Loss

Background: Distal tibial allograft (DTA) reconstruction for glenoid bone loss is nonanatomic, as it does not match the glenoid radius of curvature (ROC) in the anterior-posterior (AP) plane. The dorsal articular portion of the distal radius has not been previously described as an allograft reconstruction option for glenoid bone loss. Purpose: To evaluate distal radius fresh-frozen allograft (DRA) as a potential match for glenoid reconstruction. Study Design: Controlled laboratory study. Methods: Eighteen fresh-frozen human cadaveric specimens—including 6 shoulder, 6 wrist, and 6 tibia specimens—were used. The ROC and the graft length were measured in the superior-inferior (SI) plane. A 30% defect was created in all glenoid specimens, and both DTAs and DRAs were harvested to assess graft fit after fixation. Computed tomography analysis was used to assess bony ROC and bone mineral density (BMD). Results: The cadaveric specimens had a mean age of 77 years. The mean SI glenoid length was 39.7 mm compared with 36.8 mm for the DRA and 30 mm for the DTA. The ROC in the SI plane was 29 ± 5.3 mm for the glenoid, 37.8 ± 4.9 mm for the DRA, and 24 ± 3.7 mm for the DTA. In the AP plane, the ROC was 39.6 ± 6.6 mm for the glenoid, 30.4 ± 18.6 mm for the DRA, and 126.3 ± 9.5 mm for the DTA. On computed tomography analysis, the ROC in the SI plane was 30.4 ± 1.5 mm for the glenoid, 30.3 ± 5.6 mm for the DRA, and 24.5 ± 9.4 mm for the DTA. In the AP plane, the ROC was 30.8 ± 2 mm for the glenoid, 19.1 ± 2.3 mm for the DRA, and 46.7 ± 21.7 mm for the DTA. The BMD was 226.3 ± 79 Hounsfield units (HU) for the glenoid, 228.5 ± 94.7 HU for the DRA, 235 ± 96.2 HU for the coracoid process, and 235.1 ± 84.6 HU for the DTA. Conclusion: Compared with the DTA, the DRA had a greater mean graft length in the SI plane, providing utilization in cases of larger bony defects; the DRA has a more acute ROC in the AP plane (closer to that of the glenoid), providing a greater potential buttress to anterior humeral translation. Compared with currently utilized grafts, the DRA BMD was not significantly diminished. This study presents the DRA as a novel allograft reconstruction option in the setting of anterior glenoid bone loss; further biomechanical and clinical investigation is indicated.

The Posteromedial Approach for Harvesting Hamstring Autografts Results in Fewer Incidents of Saphenous Nerve Injury Compared to the Conventional Anteromedial Approach: A Systematic Review and Meta-Analysis.

The hamstring autograft can be harvested using various skin incisions, such as vertical, transverse, and oblique incisions, and from different localizations, including anteromedial and posteromedial harvest sites. The aim of this study was to compare studies on the anteromedial and posteromedial approaches for hamstring autograft harvest in terms of clinical outcomes, saphenous nerve injury, infection, operative time, graft length, incision length, range of motion, and patient satisfaction. Following the 2020 Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, a search was conducted in PubMed and Scopus, focusing on studies comparing anteromedial and posterior approaches for hamstring harvest. This study was registered with the PROSPERO International Prospective Register of Systematic Reviews (CRD42023450249). Methodological quality was evaluated using the Modified Coleman Methodology Score. Odds ratios (ORs) and mean differences (MDs) quantified dichotomous and continuous outcomes, respectively. Five articles, involving 405 knees, underwent analysis. Four studies were level 3 evidence, while 1 was level 1. The anteromedial hamstring harvest showed higher rates of saphenous nerve injury (OR, 9.77; 95% confidence interval [CI], 2.19-43.65; p = 0.003) and longer operative times, with an MD of about 13 minutes (MD, 13.33; 95% CI, 0.68-25.97; p = 0.04), compared to the posteromedial approach. The anteromedial method yielded a longer semitendinosus graft, with an MD of about 17 mm (MD, 17.57; 95% CI, 7.17-27.98; p = 0.0009). However, no significant differences existed in range of motion, flexion contracture, unintentional graft harvest, infection rates, and patient-reported outcomes. Notably, the posteromedial group reported higher cosmetic satisfaction, with 92% being very satisfied, compared to the anteromedial group with 80% (p = 0.005). However, overall satisfaction levels were similar between the 2 groups (p = 0.35), with a very satisfied rate of 72% for the anteromedial group and 78% for the posteromedial group. The anteromedial hamstring harvest showed greater saphenous nerve injury and longer operative times compared to the posteromedial approach, along with a longer graft. However, no significant differences were observed in the range of motion, flexion contracture, graft harvest, infection, or patient outcomes.

Application of three-dimensional printing technology to the customized design of spinal implants

Abstract In recent years, the field of 3D printing technology has experienced rapid advancements, notably expanding its application within the medical sector. This study focuses on the custom design of 3D-printed spinal implants, specifically examining porous interbody fusion products. It integrates considerations of mechanical strength and bone ingrowth to establish a finite element model of porous interbody fusion, subsequently conducting topology optimization to design three distinct types of spinal interbody fusion implants. Analytical investigations were carried out on the stress and displacement responses of these three implant types under compressive loading. Furthermore, a detailed stress analysis was conducted on implants varying in porosity, length, and screw angle of the bone graft to assess the performance characteristics of the porous interbody fusion devices. Results indicated that the Type C implant exhibited superior performance, demonstrating a stress reduction to 89.21 MPa and a displacement change of 0.006 mm, optimally at a 60% porosity level. Adjustments in the lengths and screw clamp angles of the splint ensured that the maximal stress experienced by each vertebra remained below the yield limits of both cortical and cancellous bone, thus preventing vertebral damage. This paper presents a comparative analysis of three types of porous interbody fusion devices, providing substantial data support and a theoretical framework that can inform the future development of fusion products.

Less invasive bonnet bypass with subcutaneous tunneling method for common carotid artery occlusion - A technical note.

Common carotid artery occlusion (CCAO) sometimes requires vascular reconstruction. Ipsilateral superficial temporal artery (STA)-middle cerebral artery (MCA) bypass is unsuitable due to insufficient blood flow to the external carotid artery. The bonnet bypass, one treatment option for CCAO, requires a long coronal incision and bone groove to prevent malposition and collapse of an interposition graft. However, this long incision might lead to skin complications and reduced collateral blood flow. A 60-year-old man who experienced recurrent ischemic stroke presented with the right internal carotid artery occlusion and left CCAO. The left STA was unavailable; however, both branches of his right STA were well-developed. Minimizing skin invasion was a priority because the patient had diabetes mellitus. We performed a right STA parietal branch - right MCA anastomosis, followed by a right STA frontal branch - left radial artery graft (RAG) - left MCA bonnet bypass using small intermittent skin incisions. We drilled a bone groove extending across the entire length of the interposition graft through the small intermittent skin incisions. Furthermore, we applied a right STA-RAG end-to-side anastomosis instead of an endto-end anastomosis to preserve collateral skin anastomosis. Postoperatively, the bypass remained patent, and the patient was discharged without complications. The bonnet bypass is a potential treatment for CCAO, but the procedure is invasive. Our modified bonnet bypass method enables less invasive management, preventing collapse and malposition of the interposition graft and minimizing skin complications.

Functional Outcomes of Anatomic Single Bundle Primary ACL Reconstruction with Peroneus Longus Tendon (Without a Peroneal Tenodesis) Versus Hamstring Autografts.

There is a paucity of comparative studies on the Peroneus longus tendon versus conventional hamstring autograft use in primary single-bundle ACL reconstruction. To date, there are no studies that reported donor ankle functional outcomes when a peroneus longus graft is harvested without performing a tenodesis to peroneus brevis. A single-center retrospective comparative study was undertaken to evaluate the functional outcomes (IKDC & Tegner-Lysholm scores) of primary isolated single bundle anatomic ACL Reconstruction with Peroneus Longus tendon (PL group) versus Hamstring (HT group) autografts. Further, an evaluation of donor ankle morbidity using the AOFAS score for the PL group and persistent anteromedial thigh pain and paraesthesia around the knee for the HT group was also performed. 30 patients were evaluated in each group. The mean graft diameter was 8.61 +/- 0.66mm (HT) & 9.6 +/- 0.84mm (PL) and the mean graft length was 7.39cm (HT) & 7.86cm (PL) respectively. The mean IKDC scores were 58.2 (Pre-op) & 89.52 (1 year) for the HT group and 61.8 (Pre-op) & 90.9 (1 year) for the PL group respectively. The mean Tegner-Lysholm scores were 69.83 (Pre-op) & 91.96 (1 year) for the HT group and 70.66 (Pre-op) & 92.36 (1 year) for the PL group respectively.10% of the HT group had residual anteromedial thigh pain & 6.7% had paraesthesia at one-year follow-up. In the PL group, the mean AOFAS score was 96.37 +/- 2.49 at the end of one year. Two cases (6.66%) reported paraesthesia around the harvested site. Peroneus longus tendon appears to be a better autograft choice than hamstrings for primary ACL reconstruction. Further, without a peroneal tenodesis, the functional outcomes of the donor ankle remained excellent.

Arthroscopic Reconstruction of Injured Anterior Cruciate Ligament Using Peroneus Longus Graft With Fixed Loop Endobutton - A Prospective Study.

ACL injuries are more common amongst active young people where RTA and sports injuries predominate as the most common methods of injury ACL reconstruction with peroneus longus graft method have been used more frequently nowadays. The advantages of peroneus longus graft are, Adequate graft length of minimum of 25 to 30 cm. Adequate thickness of minimum 8.5 to 9mm,Less incidence of graft thinning, Lesser hamstring and quadriceps weakness, Minimal donor site morbidity. Minimal restriction of ankle movements. A prospective study of 25 patients with injured anterior cruciate ligament without meniscal injury within the age group of 18-55 years managed with arthroscopic reconstruction of anterior cruciate ligament with peroneus longus graft and fixed loop endobutton at femoral side and interference screw at tibial side. Functional outcome was assessed using clinical examination, International Knee Documentation committee and Lysholm knee scoring scale, FADI score (foot and ankle disability index score). Patients were followed up at 2, 4, 8, 12weeks and 6, 8 months post-operatively. This study consists of 25 cases of Anterior Cruciate Ligament injury. ACL rupture was common in second and third decade of life. In our study, 18(63.34%) were sports related injuries, 5(26.66%) were due to road traffic accidents and 2(10%) were atraumatic degenerations. 22(80%) showed excellent results and 3(20%) showed good results. Arthroscopic ACL reconstruction using peroneus longus graft and Fixed-loop Endobutton and interference screws provided excellent post-operative clinical outcome in terms of knee stability, subjective knee and ankle function and range of movements of the knee and ankle in our study.

Micro-ballistic response of thin film polymer grafted nanoparticle monolayers.

Self-assembled polymer grafted nanoparticles (PGNs) are of great interest for their potential to enhance mechanical properties compared to neat polymers and nanocomposites. Apart from volume fraction of nanoparticles, recent experiments have suggested that nanoscale phenomena such as nanoconfinement of grafted chains, altered dynamics and relaxation behavior at the segmental and colloidal scales, and cohesive energy between neighboring coronas are important factors that influence mechanical and rheological properties. How these factors influence the mechanics of thin films subject to micro-ballistic impact remains to be fully understood. Here we examine the micro-ballistic impact resistance of PGN thin films with polymethyl methacrylate (PMMA) grafts using coarse-grained molecular dynamics simulations. The grafted chain length and nanoparticle core densities are systematically varied to understand the influences of interparticle spacing, cohesion, and momentum transfer effects under high-velocity impact. Our findings show that the inter-PGN cohesive energy density (γPGN) is an important parameter for energy absorption. Cohesion energy density is low for short grafts but quickly saturates around entanglement length as adjacent coronas interpenetrate fully. The response of γPGN positively influences specific penetration energy, , which peaks before chain entanglement starts (<Ne). We further divide the ballistic response into three regimes based on grafted chain length: short graft, intermediate graft, and entangled graft. The short grafted PGNs show fragmentation due to almost no cohesion between particles, and the rigid body motion of the nanoparticles absorbs most of the energy. When chains are in the intermediate graft length regime, the film fails by chain pull-out, and unraveling of grafts is the primary dissipation mechanism. The Ashby plot of penetration energy, Ep, indicates ballistic processes are inelastic collisions when grafted chains are short and vary with density in a power law fashion as expected from momentum transfer. The response indicates that a lower nanoparticle weight fraction, ϕwtNP, leads to higher energy absorption per mass, that is, the added mass of nanoparticles does not warrant proportionate increases in energy absorption in the parametric range studied. However, the peak deceleration, Ab, shows a clear positive effect of adding NPs. Finally, PGNs with intermediate chain lengths simultaneously show relatively higher and Ab.

Novel technique of predicting the dimensions of 5-stranded hamstring grafts for anterior cruciate ligament reconstruction: A descriptive study

BackgroundPrediction of hamstring tendon autografts is essential when planning a ligament reconstruction surgery. This is especially important in cases of multiple ligament reconstruction surgeries. This study was designed to predict the dimensions of 5-stranded hamstring grafts from anthropometric parameters in patients undergoing anterior cruciate ligament (ACL) reconstruction surgery. Methods172 patients undergoing ACL reconstruction with hamstring autografts were included in the study. Preoperative parameters included age, gender, height, weight, body mass index (BMI), thigh length, thigh circumference, and tibia length; intraoperative parameters included semitendinosus (ST) and gracilis (G) length and diameter, final 5-stranded graft length and diameter. Pre-operative data was correlated with intra-operative data using tests of significance. ResultsHeight, tibia and thigh length were greater in males (p < 0.05) whereas BMI was greater in females (p < 0.05). G and ST length alongwith 5-stranded graft length and diameter were significantly greater in males (p < 0.05). The graft dimensions could be correlated with the pre-operative anthropometric parameters using specific equations. This was applicable to the lengths and diameters of ST, G and 5-stranded grafts. We also noted that an increase in age was associated with a reduction in graft dimensions except for the diameter of G graft in females and length of 5-stranded grafts in males. Conclusion5-stranded hamstring graft dimensions can be reliably predicted using anthropometric parameters and this eases surgical planning.

A Cadaveric Study of the Optimal Isometric Region on the Anterolateral Surface of the Knee in Anterolateral Ligament Reconstruction.

Isolated intra-articular anterior cruciate ligament (ACL) reconstruction is not capable of restoring instability in many cases leading some to recommend concomitant anterolateral ligament (ALL) reconstruction. The satisfactory fixation site and graft length change are crucial in ligament reconstruction to restore the ALL function and avoid some unwanted graft behavior. The purpose of this investigation is to determine the optimal isometric region on the anterolateral aspect of the knee for ALL reconstruction using a three-dimensional optical instrument and a suture similar to an intraoperative isometric test. Six freshly frozen cadaveric human knees were used in this study. Data regarding the anterolateral surface were obtained using an optical measurement system to create a three-dimensional model. Nine points were selected on the femur (F1-F9) and tibia (Ta-Ti) respectively. The three-dimensional length change between each pair of tibial and femoral points was measured during passive knee flexion from 0° to 90° in 15° increments. Subsequently, five femoral points (A-E) were selected from the lateral femur, located in different areas relative to the lateral femoral epicondyle, and three tibial reference points (T1-T3) were selected in the isometric test. The changes in the length between each pair of reference points were measured using sutures. The 95% confidence interval for the rate of length change was estimated using the mean and standard deviation of the maximum rate of length change at different flexion angles, and the data were expressed as the mean (95% confidence interval) and compared with the maximum acceptable rate of change (10%). The maximum acceptable change rate for ligament reconstruction is 10%, and the mean maximum rates and the 95% confidence interval (CI) of length change for the point combinations were calculated. Among all the combined points measured using the optical measurement system and the suture, the qualified point combination for reconstruction was F3 (8mm posterior and 8mm proximal to the lateral femoral epicondyle)-Tb (8mm proximal to the midpoint between the center of Gerdy's tubercle and the fibula head), A (posterior and proximal to the lateral femoral epicondyle)-T2 (10mm below the joint line)and A-T3 (15 mm below the joint line). The position of F3-Tb and A-T2 are close to each other. The most isometric area of the femur for ALL reconstruction was posterior and proximal to the lateral femoral epicondyle. We recommend that the initial location of the femoral point be set at 8 mm posterior and 8 mm proximal to the lateral femoral epicondyle and the tibial point at approximately 10 mm below the joint line, midway between Gerdy's tubercle and fibular head, and subsequently adjusted to the most satisfactory position according to the isometric test.

Demulsification efficiency and mechanism of hydrophobic carbon chains modified hyperbranched polyethylenimide on oil-in-water emulsion

A series of amphiphilic hyperbranched polyethylenimine (HPEI-Cn) with different length hydrophobic carbon chains were synthesized by amidation modification of hyperbranched polyethylenimine (HPEI), which can be used for separation of oil-in-water emulsion. The demulsification effect of HPEI-Cn under different demulsifier concentration, temperature, settling time and pH value were evaluated by bottle test method. The results indicated that the demulsification efficiency (DE) of HPEI-Cn increased with the increase of graft length of carbon chain. Encouragingly, the HPEI-C16 had the characteristics of small amount (50 mg/L), short settling time (30 min) and wide temperature adaptation range (20–60 °C). Through three-phase contact angle tests (CA), dynamic interfacial tension tests (IFT), elastic modulus analysis, Zeta potential and microscope observation, the demulsification mechanism of HPEI-Cn was systematically revealed. The excellent DE of HPEI-C16 was attributed to the high interfacial activity and appropriate length of hydrophobic groups. On the one hand, the high interfacial activity drives hyperbranched macromolecules to rapidly diffuse and adsorb to the oil-water interface. On the other hand, it contains appropriate hydrophobic carbon chains C16 to flocculate and coalesce oil droplets, thus achieving efficient demulsification.

Evaluation of changes in the length and cross-sectional dimension of autogenous grafts from semitendinosus and gracilis tendons used for anterior cruciate ligament (ACL) reconstruction in patients with active growth plates: MRI analysis

Introduction. In recent years, there has been an increase in anterior cruciate ligament (ACL) injuries during childhood and adolescence. Aim. The aim of this study is to observe the diameter and length of the graft change in the postoperative period. Materials and methods. The study group consisted of 21 adolescents (11 boys and 10 girls) who underwent ACL reconstruction using hamstring and gracilis tendon grafts. MRI evaluations were performed at 3-6 and 24-26 months postoperatively to assess the width and length of the graft. The graft cross-sectional dimension was measured at the mid-substance of the tendons on sagittal scans in T1 and T2-weighted sequences. Length measurement was performed on axial ACL scans at its central portion (assessing mid-substance length). The collected measurements from both postoperative periods were compared and statistically analysed. Results. MRI analysis conducted postoperatively showed a statistically significant decrease in graft cross-sectional dimension, from an average 7.21-5.82 mm. The intra-articular graft length measured in MRI at 3-6 months post-surgery averaged 21.52 mm, while the length measured at 24-26 months post-surgery averaged 22.42 mm. Conclusions. Postoperative MRI analysis of reconstructed ACLs in adolescents with active growth plates demonstrated a reduction in graft cross-sectional dimension and a slight increase in graft length.

Feasibility and accuracy of real-time 3D-holographic graft length measurements.

Mixed reality (MR) holograms can display high-definition images while preserving the user's situational awareness. New MR software can measure 3D objects with gestures and voice commands; however, these measurements have not been validated. We aimed to assess the feasibility and accuracy of using 3D holograms for measuring the length of coronary artery bypass grafts. An independent core lab analyzed follow-up computer tomography coronary angiograms performed 30 days after coronary artery bypass grafting in 30 consecutive cases enrolled in the FASTTRACK CABG trial. Two analysts, blinded to clinical information, performed holographic reconstruction and measurements using the CarnaLife Holo software (Medapp, Krakow, Poland). Inter-observer agreement was assessed in the first 20 cases. Another analyst performed the validation measurements using the CardIQ W8 CT system (GE Healthcare, Milwaukee, Wisconsin). Seventy grafts (30 left internal mammary artery grafts, 31 saphenous vein grafts, and 9 right internal mammary artery grafts) were measured. Holographic measurements were feasible in 97.1% of grafts and took 3 minutes 36 s ± 50.74 s per case. There was an excellent inter-observer agreement [interclass correlation coefficient (ICC) 0.99 (0.97-0.99)]. There was no significant difference between the total graft length on hologram and CT [187.5 mm (157.7-211.4) vs. 183.1 mm (156.8-206.1), P = 0.50], respectively. Hologram and CT measurements are highly correlated (r = 0.97, P < 0.001) with an excellent agreement [ICC 0.98 (0.97-0.99)]. Real-time holographic measurements are feasible, quick, and accurate even for tortuous bypass grafts. This new methodology can empower clinicians to visualize and measure 3D images by themselves and may provide insights for procedural strategy.

Reconstruction of the ulnar artery in Guyon’s canal with an arterial graft: Anatomical study

Ulnar artery thrombosis in Guyon’s canal can lead to vascular insufficiency in the fingers. The recommended treatment is resection and reconstruction of the pathological area. A bypass may be necessary, which may be venous or arterial. Arterial bypasses have better long-term patency; however, they are a source of donor-site complications.We carried out an anatomical study on 11 upper limbs and 7 lower limbs from cadavers to identify a technically accessible arterial graft, of a diameter suitable for bypassing the ulnar artery in Guyon’s canal and with acceptable scar sequelae (few predicted postoperative complications, discreet size and/or location of scar).Three grafts were considered: anterior interosseous artery, radial recurrent artery and descending genicular artery. The various grafts were dissected and harvested from cadaver specimens, then their lengths and diameters were measured. The diameter of the candidate grafts was compared to the diameter of the distal ulnar artery.The diameter of the descending genicular artery matched the ulnar artery better than the radial recurrent artery or the anterior interosseous artery (103% vs 44% and 67%, respectively). Mean graft length was 6.6 cm. The anatomical configuration of the descending genicular artery allowed Y-shaped bypasses to be performed. Harvesting this artery appears to cause little damage and allows bypasses up to 6 cm to be performed.Despite its smaller diameter making it necessary to perform a microvascular size adjustment, the anterior interosseous artery is a candidate graft because it is long enough (119 mm) and located near the surgical site. Level of evidenceV.

Feasibility and accuracy of real-time 3D-holographic graft length measurement, a sub-study of the FAST-TRACK CABG trial

Abstract Background 3D Hologram is an emerging tool for intuitively manipulating and visualizing CT images. Mixed reality (MR) technology can display high-definition 3D holograms while preserving situational awareness. The new MR software offers the possibility to measure 3D objects using hand gestures and voice commands. However, these measurements made on 3D holograms have not been validated. Purpose We aimed to assess the feasibility and accuracy of using CT-derived 3D holograms for bypass graft length measurement. Methods Twenty-seven consecutive cases in the FAST TRACK CABG trial were included. The post-operative CT images performed at 30 days follow-up were analyzed in an independent core lab. Two analysts blinded to clinical information performed Holographic reconstruction and measurement using the CanaLife Holo software (Medapp, Krakow, Poland). (Figure 1) Inter-observer agreement was assessed in the first 20 cases. Another analyst with full access to clinical information performed the validation measurements on the CardIQ W8 system (GE Healthcare, Milwaukee, Wisconsin). (Figure 1) Results A total of 62 grafts (27 left internal mammary artery grafts, 27 saphenous vein grafts, and 8 right internal mammary artery grafts) were measured. There was an excellent inter-observer agreement between the analysts in the first 47 grafts analyzed (interclass correlation 0.9879 [0.9783-0.9933]). (Figure 2A, 2B) On average, holographic reconstruction and measurement of a case took 3 minutes and 36 seconds± 50.74 seconds compared to around 10 minutes per vessel on the traditional CT system. There was no significant difference between the graft length measured by hologram and CT (188.59±51.63 mm vs. 183.95±50.93 mm, p=0.616). The length measured by hologram and CT were similar across different graft types. The measurements of hologram and CT are highly correlated (r=0.973, p &amp;lt;0.001) with an excellent agreement (interclass correlation 0.9928 [0.9880-0.9957]). (Figure2C, 2D) Conclusion Holographic vessel length measurement is feasible, fast, and accurate even for tortuous coronary bypass grafts. This new methodology can empower surgeons to visualize and measure the results of their work by themselves and may provide insights for procedure evaluation. 3D Holograms can eventually empower surgeons to plan the precise length of the arterial and venous grafts to be harvested for every individual case.