Surgical Implantation Research Articles

Clinical Applicability and Safety of Conventional Frame-Based Stereotactic Techniques for Stereoelectroencephalography.

Stereoelectroencephalography (SEEG) is increasingly being recognized as an important invasive modality for presurgical evaluation of epilepsy. This study focuses on the clinical and technical considerations of SEEG investigations when using conventional frame-based stereotaxy, drawing on institutional experience and a comprehensive review of relevant literature. This retrospective observational study encompassed the surgical implantation of 201 SEEG electrodes in 16 epilepsy patients using a frame-based stereotactic instrument at a single tertiary-level center. We provide detailed descriptions of the operative procedures and technical nuances for bilateral and multiple SEEG insertions, along with several illustrative cases. Additionally, we present a literature review on the technical aspects of the SEEG procedure, discussing its clinical implications and potential risks. Frame-based SEEG electrode placements were successfully performed through sagittal arc application, with the majority (81.2%) of cases being bilateral and involving up to 18 electrodes in a single operation. The median skin-to-skin operation time was 162 minutes (interquartile range [IQR], 145-200), with a median of 13 minutes (IQR, 12-15) per electrode placement for time efficiency. There were two occurrences (1.0%) of electrode misplacement and one instance (0.5%) of a postoperative complication, which manifested as a delayed intraparenchymal hemorrhage. Following SEEG investigation, 11 patients proceeded with surgical intervention, resulting in favorable seizure outcomes for nine (81.8%) and complete remission for eight cases (72.7%). Conventional frame-based stereotactic techniques remain a reliable and effective option for bilateral and multiple SEEG electrode placements. While SEEG is a suitable approach for selected patients who are strong candidates for epilepsy surgery, it is important to remain vigilant concerning the potential risks of electrode misplacement and hemorrhagic complications.

A Review on 3D Printing Processes in Pharmaceutical Engineering and Tissue Engineering: Applications, Trends and Challenges

AbstractAs a 3D rapid prototyping technology, 3D printing (3DP) technology has been widely applied in medical research, fabricating various medical devices or implants. With the development of biomaterials and cell‐related technologies, 3DP, especially bioprinting technology, is quietly bringing great changes and opportunities in the medical industry. Beyond surgical models, medical devices, and implants, traditional 3DP, cell‐based 3D bioprinting, and emerging 4D printing (4DP) have significantly aided in the advancement and manufacture of pharmaceuticals and biological alternatives for tissue engineering. It is envisioned that future healthcare systems, based on evolving 3DP technology and precision medicine, will deliver customized solutions that cater to the unique differences and needs of each patient. In this review work, several mainstream 3D bioprinting technologies are presented, with a focus on recent advances in 3DP for pharmaceutical engineering and important tissue engineering, including vascular and bone tissue engineering. Challenges and future prospects of 3DP for drug discovery, drug delivery systems, artificial blood vessels, vascular and bone tissue engineering scaffolds, and practical applications are also covered. Finally, the differences between 3DP and 4DP, as well as the advantages and disadvantages of different stimulus response mechanisms in 4DP and their potential applications are summarized.

Performance and Failure of Right Ventricle to Pulmonary Artery Conduit in Congenital Heart Disease

Surgical implantation of a right ventricle to pulmonary artery (RV-PA) conduit is an important component of congenital heart disease (CHD) surgery, but with limited durability, leading to re-intervention. The present single-center, retrospective, cohort study reports the results of surgically implanted RV-PA conduits in a consecutive series of children and adults with CHD. Patients with CHD referred for RV-PA conduit surgical implantation (from October 1997 to January 2022) were included. The primary outcome was conduit failure, defined as a peak gradient above 64 mm Hg, severe regurgitation, or the need for conduit-related interventions. Longitudinal echocardiographic studies were available for mixed-effects linear regression analysis. A total of 252 patients were initially included; 149 patients were eligible for follow-up data collection. After a median follow-up time of 49 months, the primary study end point occurred in 44 (29%) patients. A multivariable Cox regression model identified adult age (>18 years) at implantation and pulmonary homograft implantation as protective factors (hazard ratio 0.11, 95% confidence interval [CI] 0.02 to 0.47 and hazard ratio 0.34, 95% CI 0.16 to 0.74, respectively). Fever within 7 days of surgical conduit implantation was a risk factor for early (within 24 months) failure (odds ratio 4.29, 95% CI 1.41 to 13.01). Long-term use of oral anticoagulants was independently associated with slower progression of peak echocardiographic gradient across the conduits (mixed-effects linear regression p = 0.027). In patients with CHD, the rate of failure of surgically implanted RV-PA conduits is higher in children and after nonhomograft conduit implantation. Early fever after surgery is a strong risk factor for early failure. Long-term anticoagulation seems to exert a protective effect.

Surgical Bone Implantation Technique for Rat Tibia Models of Diabetes and Osteoporosis.

The rat has long served as a valuable animal model in implant dentistry and orthopedics, particularly in studying the interactions between biomaterials and bone tissue. The rat's tibia is frequently chosen due to its easy surgical access through thin tissue layers (skin and muscle) and the flattened shape of its medial face, facilitating the surgical insertion of intraosseous devices. Additionally, this model enables the induction of specific diseases, mimicking various clinical conditions to assess biological responses to different implant conditions like geometry, surface texture, or biological cues. However, despite its robust cortical structure, certain intraosseous devices may require adaptations in design and size for successful implantation. Therefore, establishing standardized surgical methods for manipulating both soft and hard tissues in the implantation region is essential for ensuring proper implant or screw device placement, particularly in fields like implant dentistry and orthopedics. This study included eighty Sprague Dawley rats divided into two groups based on their respective diseases: Group 1 with osteoporosis and Group 2 with Type 2 Diabetes. Implantations were performed at 4 weeks and 12 weeks, with the same surgeon following a consistent surgical technique. A positive biological response was observed, indicating complete osseointegration of all implants placed. These results validate the success of the surgical protocol, which can be replicated for other studies and serve as a benchmark for the biomaterials community. Notably, osseointegration values remained stable at both 4 weeks and 12 weeks for both disease models, demonstrating a durable integration of the implant over time and emphasizing the establishment of an intimate bone connection as early as 4 weeks.

Surgical Implantation of Single-Staged Tissue-Engineered Urothelial Tubes in a Minipig Model.

Reconstructive surgeries are often challenged by a lack of grafting tissue. In the treatment of urogenital malformations, the conventional solution has been harvesting gastrointestinal tissue for non-orthotopic reconstruction due to its abundance to reestablish normal function in the patient. The clinical outcomes after rearranging native tissues within the body are often associated with significant morbidity; thus, tissue engineering holds specific potential within this field of surgery. Despite substantial advances, tissue-engineered scaffolds have not yet been established as a valid surgical treatment alternative, mainly due to the costly and complex requirements of materials, production, and implantation. In this protocol, we present a simple and accessible collagen-based tubular scaffold embedded with autologous organ-specific tissue particles, designed as a conduit for urinary diversion. The scaffold is constructed during the primary surgical procedure, comprises commonly available surgical materials, and requires conventional surgical skills. Secondly, the protocol describes an animal model designed to evaluate the short-term in vivo outcomes post-implantation, with the possibility of additional variations to the procedure. This publication aims to demonstrate the procedure step-by-step, with special attention to the use of autologous tissue and a tubular form.

Impact of thermal energy efficiency based on kerosene oil movement through hybrid nano-particles across contracting/stretching needle

This manuscript reveals the mathematical analysis of dual simulations in tangent hyperbolic rheology with heat transfer and mass diffusion mechanisms on the needle (expanding and shrinking). Further, Darcy's Forchhiermer law is employed with the occurrence of the magnetic field. The models of hybrid nanofluid utilized are Xue- and YO-hybrid nano-fluid models. Such models apply to optical fibers, solar systems, surgical implants, electronics and biological applications. Transfer of thermal energy and diffusion related to mass species occurs employing a non-Fourier approach. The transformed system of non-linear Odes is numerically tackled with the finite element method. Furthermore, because fluid and needle movement have opposite directions, the current model has dual solutions. It visualizes that such a complicated model is not solved numerically by FEM. The applications of Xue- and YO-hybrid nano-fluid model with non-Fourier's law on a needle are implemented for the first time. It concludes that adding YO-hybrid nanofluid with base fluid increases the entropy profile, temperature profile and Bejan profile rather than the Xue hybrid nanofluid model. Fields of concentration, velocity and heat energy for the case of upper solutions are higher than concentration, velocity and heat energy profiles for lower solutions.

Sex-specific aspects on prognosis after aortic valve replacement for aortic stenosis: a SWEDEHEART registry study

ObjectiveTo compare long-term cardiovascular (CV) outcomes between men and women with aortic stenosis (AS) undergoing aortic valve replacement (AVR) by the type of valve implant.MethodsThe study population consisted of 14...

Analysis of Calcaneal Avulsion Fractures Treated Surgically and Nonsurgically: A Retrospective Multicenter Study.

Calcaneal avulsion fractures (CAvFs) at the Achilles tendon insertion are among the more challenging fractures to treat. Although rare, they often require reoperation. The optimal treatment, including nonsurgical procedures and better implants for surgical procedures in the treatment of CAvFs, remains to be established. Therefore, our study aimed to (1) perform a descriptive evaluation of CAvFs, including cases managed nonsurgically, and (2) assess surgical procedures, including the incidence of complications and reoperation for surgically treated CAvFs. In this multicenter retrospective study, we collected data of patients with CAvFs treated at 9 hospitals from 2012 to 2022. We performed a descriptive study of CAvFs and compared postoperative complications and reoperation rates for multiple surgical techniques and implants. The size of the bone fragments was quantified. The data of 70 patients with CAvFs were analyzed; 20 patients were treated nonsurgically, and 50 were treated surgically. The mean age of patients was 68.5 years; 67% of the patients were female. Nineteen percent of the patients had diabetes, and 19% had osteoporosis. The incidence of postoperative complications was 30%, with infection in 14%, necrosis in 26%, and loss of reduction in 18%. The reoperation rate was 22%. Surgical techniques with use of cannulated cancellous screws were performed in 80% of the surgical cases. Cannulated cancellous screw (CCS) fixation alone resulted in a reoperation rate of 35%, whereas additional augmentation, including washers with CCS fixation, resulted in a reoperation rate of 10%. CCS fixation was successfully performed, although suture anchors were used in some cases with smaller fragments. CAvFs occurred more frequently in older women and had a high rate of postoperative complications. A combination of CCS with augmentation was more effective at reducing postoperative complications than CCS fixation alone, even when the bone fragment size was small. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

PRIMARY VITREORETINAL LYMPHOMA MASQUERADING AS POSTOPERATIVE ENDOPHTHALMITIS IN A PREGNANT PATIENT WITH LONG-STANDING IDIOPATHIC PANUVEITIS.

To report primary vitreoretinal lymphoma after surgical 0.59 mg fluocinolone acetonide implant (FAi) exchange in a patient treated with adalimumab for idiopathic bilateral panuveitis. Retrospective case review. A 37-year-old woman with bilateral idiopathic panuveitis, who had favorable responses to previous FAi surgical implants, presented with right eye recurrent intraocular inflammation and cystoid macular edema that partially responded to systemic adalimumab. Her FAi was replaced, given her previous favorable response. She developed postoperative ocular inflammation transiently responsive to two serial vitreous taps and injections of intravitreal antimicrobials and then worsening inflammation and new layered flocculant material. Diagnostic vitrectomy showed a few atypical lymphocytes and cultures were negative. At postdiagnostic vitrectomy Month 1, flocculant material recurred. Aqueous cytology and flow cytometry revealed large CD45-positive B cells suspicious for lymphoma. Postoperatively, she revealed that she was pregnant. She was treated with eight monthly intravitreal methotrexate injections and postpartum consolidation radiotherapy. Subsequent repeat cytology, flow cytometry, and corneal pathologic examination revealed large B cells that were CD20 positive, and next-generation sequencing detected a dominant monoclonal B-cell population, diagnostic of PVRL. Nineteen months after FAi exchange, she developed an area of enhancement in the lateral aspect of the right frontal lobe on brain MRI, consistent with central nervous system involvement. The authors present a unique case of PVRL masquerading as postoperative endophthalmitis after FAi exchange in an eye with chronic panuveitis treated with adalimumab immunosuppressive therapy. The authors hypothesize that there may be a causal relationship between adalimumab and PVRL.

Microcalorimetric study of the bactericidal action of titanium tetrachloride on the Pseudomonas aeruginosa growth. Potential implications in orthopaedic surgery

With the rising use of metallic implants worldwide, bacterial infection has become a major concern due to its significant impact on patient health and national healthcare budgets. This study aimed to evaluate the sensitivity of Pseudomonas aeruginosa, a common bacterium responsible for implant surgery infections, to different concentrations of titanium tetrachloride (TiCl4) solutions. Microcalorimetry was used to analyze the heat output produced by bacteria metabolism when exposed to TiCl4 at concentrations ranging from 0 to 10 mM, as well as a saturated solution. The inner chamber of the calorimeter was set to the physiological temperature of the human body (309.65 K), and the heat output produced by bacteria metabolism was collected at intervals of 22.2 s for 48 h using a data acquisition and processing system. The data was then represented as thermograms. The results showed that higher concentrations of TiCl4 had a bactericidal effect on the growth of Pseudomonas aeruginosa. This study supports the potential use of higher concentrations of this compound in surgical implants to reduce the risk of infection development due to its bactericidal properties.

Development and Evaluation of an AZ31 Magnesium Alloy and Eggshell Powder Composite for Orthopedic Surgical Implants

This research investigates the development and evaluation of a novel composite material composed of AZ31 magnesium alloy and eggshell powder, designed for use in surgical bone implants. The primary objective is to enhance the mechanical properties and biocompatibility of AZ31 by incorporating eggshell powder, which is known for its hardness and strength. The composite is fabricated using the stir casting technique, where the molten magnesium is mixed with finely ground eggshell powder to achieve uniform dispersion. The resulting samples are subjected to rigorous mechanical testing, including tensile and compressive strength evaluations, as well as hardness measurements. Additionally, the internal structure and particle distribution of the composite are analyzed using scanning electron microscopy and X-ray diffraction, respectively. This study aims to provide a comprehensive understanding of the material properties and structural characteristics of the composite, with a focus on its potential applications in orthopedic load-bearing implants and fixation devices, such as bone plates, joint replacements, screws, rods, dental implants, and cardiac stents. The findings are expected to contribute to the development of improved biomaterials for medical applications, leveraging the unique benefits of both magnesium alloy and eggshell powder.

Heart failure hospitalization following surgical or transcatheter aortic valve implantation in low-risk aortic stenosis.

In low-risk patients with severe aortic stenosis (AS), sutureless surgical aortic valve replacement (SU-SAVR) may be an alternative to transcatheter aortic valve implantation (TAVI). The risk of heart failure hospitalization (HFH) after aortic valve replacement (AVR) in this population is incompletely characterized. This study aims to investigate the incidence, predictors, and outcomes of HFH in patients undergoing SU-SAVR versus TAVI. Patients referred for AVR between 2013 and 2020 at two centres were consecutively included. The decision for SU-SAVR or TAVI was determined by a multidisciplinary Heart Team. Cox regression and competing risk analysis were conducted to assess adverse events. Of 594 patients (mean age 77.5±6.4, 59.8% male), 424 underwent SU-SAVR, while 170 underwent TAVI. Following a mean follow-up of 34.1±23.1months, HFH occurred in 112 (27.8%) SU-SAVR patients and in 8 (4.8%) TAVI patients (P<0.001). The SU-SAVR cohort exhibited higher all-cause mortality (138 [32.5%] patients compared with 30 [17.6%] in the TAVI cohort [P<0.001]). These differences remained significant after sensitivity analyses with 1:1 propensity score matching for baseline variables. SU-SAVR with HFH was associated with increased all-cause mortality (61.6% vs. 23.1%, P<0.001). Independent associates of HFH in SU-SAVR patients included diabetes, atrial fibrillation, chronic obstructive pulmonary disease, lower glomerular filtration rate and lower left ventricular ejection fraction. SU-SAVR patients with HFH had a 12-month LVEF of 59.4±12.7. In low-risk AS, SU-SAVR is associated with a higher risk of HFH and all-cause mortality compared to TAVI. In patients with severe AS candidate to SU-SAVR or TAVI, TAVI may be the preferred intervention.

A Retrospective Review of Men Referred to a Dedicated Erectile Dysfunction Clinic in Secondary Care.

Background and objectives Erectile dysfunction (ED) is a multifactorial disease associated with many medical co-morbidities and risk factors commonly encountered in primary care. Initial management includes lifestyle changes and the treatment of any identifiable conditions. Guidelines exist recommending the assessment and management of sufferers with clear indications for referral to secondary care. With the outbreak of COVID-19, non-urgent medical services, including ED, were suspended, creating a significant waiting list for these patients. The aim of this study was to review the management of men in both primary and secondary care who had been referred to a dedicated ED service. Materials and methods A retrospective review of men referred to secondary care between June 2018 and April 2021 with ED was undertaken, reviewing whether the guidelines published by the National Institute for Health and Care Excellence (NICE) and GP Notebook for the assessment, initial treatment, and referral were followed by the primary care clinician. A secondary aim was to recordthe outcome of those men after review in a secondary carededicated ED clinic. Results One hundred and forty-eight men were reviewed in the ED clinic, with 55 men (37.2%) requiring an intervention that was appropriate to have been delivered in primary care. The majority of those (76.3%) were successfully managed with a phosphodiesterase inhibitor. Of those treated in secondary care, almost 60% required a second-line therapy, such as a vacuum device or the administration of alprostadil, with 14 men (15%) necessitating the surgical implantation of a penile prosthesis. Conclusion With a rise in both the prevalence and incidence of ED, primary care physicians have a pivotal role in the screening and initial assessment of patients with ED, with evidence suggesting that a significant proportion can be successfully managed in this setting.

Complications of Pelvic Prolapse Surgery Using Mesh: A Systematic Review.

Pelvic organ prolapse (POP) is a public health problem that influences millions of women around the globe, and it has a significant impact on the quality of life. From the FDA statement regarding the complications of using mesh implants in POP surgery to studies that have shown the benefits and side effects, we conducted a systematic review investigating the complications associated with surgical mesh implantation for POP repair. Relevant studies were identified through a comprehensive search of scientific databases. Studies evaluating the use of mesh in POP surgery and reporting on associated complications were included. Among 2816 studies, 28 studies met the research criteria, with a total number of 8958 patients, revealing that in laparoscopic mesh surgery, the rate of mesh exposure was lower compared to vaginal mesh surgery, among other complications. Laparoscopic mesh surgery is superior as a long-term approach for POP repair compared to vaginal mesh surgery, offering lower complication rates and potentially better anatomical success. However, vaginal mesh surgery remains a valuable option for patients who are unsuitable for laparoscopy due to specific factors. Future research should explore alternative techniques, like pectopexy with or without mesh, to further improve surgical outcomes and patient experience.

Wireless Heart and Respiration Rate Monitoring in Birds Using Skin Mounted Eutectogel Coated Threads

AbstractAnimal‐borne biologging technology allows researchers to understand the physiological responses of wild animals, especially songbirds, to environmental changes. Songbirds are of interest in studying these responses because of their visibility and relatively small body size yet high energetic demand of their various life‐history stages (e.g., molt, migration, breeding). Previous methods for monitoring responses, such as heart rate activity, have relied on surgical implantation of electrodes connected to bulky electronic devices which affect the well‐being of birds, indirectly influence bird behavior and create stress artifacts. A non‐invasive, lightweight solution is needed. This study introduces eutectogels, a long‐lasting gel made from deep eutectic solvents, combined with conductive threads and a wireless device to monitor the heart rate of house sparrows noninvasively through skin contact. In this work, heart rate and respiration rate measurements are validated on birds under anesthesia. These tests are repeated on birds that are awake but restrained. The eutectogel outperforms commercial electrodes and gels, yielding high signal‐to‐noise ratio measurements on restrained birds. The respiration rate is extracted and processed electronically from motion artifacts in the recorded signals without the need for a separate dedicated sensor. The system shows promise for future field studies on free‐living species.

Investigation of the Effect of Hafnium Chloride on Sperm Viability and Motility in Normospermic Cases: An In Vitro Study.

Hafnium alloys are employed in medical applications due to their biocompatibility and high corrosion resistance. These alloys have demonstrated osteogenic and antimicrobial activities in surgical implants and have been utilized in the treatment of sarcoma. Additionally, a sensor based on hafnium nanoparticles has been reported for the detection of coronavirus disease 2019. Despite the increasing usage of hafnium, a literature review reveals no studies examining its effects on sperm in both human and animal species. Semen samples were analyzed according to the 2010 World Health Organization (WHO) criteria, and 20 normospermic specimens were included in the study. Three groups were formed: control, hafnium chloride 2 mg/mL, and 4 mg/mL. Motility and viability were assessed in all groups at the 20th and 40th minutes. The decrease in viable sperm count was found to be significant in the 2 mg/ml HfCl4 group (difference: 12.73 ± 0.8, p<0.001) and the 4 mg/ml HfCl4 group (difference: 41.72 ± 1.34, p<0.001) compared to the control group. A time-dependent decrease in sperm viability was significant across all groups (difference: 8.93 ± 0.59, p<0.001). The decrease in viable sperm count in the 4 mg/ml HfCl4 group was significant when compared to the 2 mg/ml HfCl4 group (difference: 29 ± 1.27, p<0.001). The decrease in total motile sperm count was observed in both the 2 mg/ml HfCl4 group (difference: 12.80 ± 1.30, p<0.001) and the 4 mg/ml HfCl4 group (difference: 35.63 ± 1.12, p<0.001) compared to the control group. Additionally, the decrease in total motile sperm count in the 4 mg/ml HfCl4 group was significant compared to the 2 mg/ml HfCl4 group (difference: 22.80 ± 1.60, p<0.001). A time-dependent decrease in total motile sperm count was also significant (difference: 6.03 ± 0.49, p<0.001). The study determined that hafnium chloride negatively affects sperm motility and viability in vitro.These effects may be due to the presence of an acidic environment. It has been demonstrated that instruments containing this element maypose a potential risk.

Combined, Pedicled Anterior Cruciate Ligament and Anterolateral Ligament Reconstruction - “PAAR” Technique

Despite constant development of surgical implants, instruments, and rehabilitation protocols, the outcomes of anterior cruciate ligament reconstruction remain unpredictable, and the failure rate of isolated procedures remains unacceptably high. Several factors possibly concerning suboptimal outcomes and risk of graft rerupture have been highlighted, among which are graft healing, tunnel position, and residual rotational instability. Recent studies have suggested that addressing anterolateral complex injury and enhancing graft healing properties might improve the outcomes of surgery. We propose a simple technique of combined anterior cruciate ligament and anterolateral ligament reconstruction using pedicled semitendinosus and gracilis tendons with a single femoral tunnel and no additional tibial tunnels.

Long-Term Outcomes of Enucleation and Secondary Orbital Implantation Surgeries Using Polyester Mesh-Wrapped Acrylic Orbital Implants.

To reveal the long-term outcomes of enucleation and secondary orbital implantation surgeries employing nonabsorbable surgical mesh-wrapped acrylic orbital implants for various reasons. A retrospective interventional study of 48 eyes that underwent primary or late primary enucleation and secondary orbital implantation using polyester mesh-wrapped acrylic orbital implants, between 2012 and 2021. Patient demographics, diagnosis, prior ophthalmic surgery, implant size, follow-up periods, and implant-associated complications were evaluated. The records of 36 patients who underwent primary or late primary enucleation and 12 who underwent secondary orbital implantation due to sphere extrusion were evaluated. Patients' mean age was 38.7 (range: 2-75) and the mean follow-up period was 48.3 months (range: 24-72mo). Major causes for surgeries were trauma and malignancies (54.1% and 33.3%, respectively). No complications, such as conjunctival dehiscence, implant exposure or extrusion, contracted socket, or fornix insufficiency were observed in any patient during the long-term follow-up period postsurgeries. Using polyester mesh-wrapped acrylic orbital implants in enucleation and secondary orbital implantation surgeries proves to be a successful, safe, and cost-effective option.

Optimized Biomanufacturing for Treatment of Volumetric Muscle Loss Enables Physiomimetic Recovery.

Volumetric muscle loss (VML) injuries are defined by loss of sufficient skeletal muscle to produce persistent deficits in muscle form and function, with devastating lifelong consequences to both soldiers and civilians. There are currently no satisfactory treatments for VML injuries. The work described herein details the implementation of a fully enclosed bioreactor environment (FEBE) system that efficiently interfaces with our existing automated bioprinting and advanced biomanufacturing methods for cell deposition on sheet-based scaffolds for our previously described tissue-engineered muscle repair (TEMR) technology platform. Briefly, the TEMR technology consists of a porcine bladder acellular matrix seeded with skeletal muscle progenitor cells and preconditioned via 10% uniaxial cyclic stretch in a bioreactor. Overall, TEMR implantation in an established rat tibialis anterior (TA) VML injury model can result in 60 to ∼90% functional recovery. However, our original study documented >50% failure rate. That is, more than half of the implanted TEMR constructs produced no functional improvement beyond no treatment/repair. The high failure rate was attributed to the untoward mechanical disruption of TEMR during surgical implantation. In a follow-up study, adjustments were made to the geometry of both the VML injury and the TEMR construct, and the "nonresponder" group was reduced from over half the TEMR-treated animals to just 33%. Nonetheless, additional improvement is needed for clinical applicability. The main objectives of the current study were twofold: (1) explore the use of advanced biomanufacturing methods (i.e., FEBE bioreactor) to further improve TEMR reliability (i.e., increase functional response rate), (2) determine if previously established bioprinting methods, when coupled to the customized FEBE system would further improve the rate, magnitude or amplitude of functional outcomes following TEMR implantation in the same rat TA VML injury model. The current study demonstrates the unequivocal benefits of a customized bioreactor system that reduces manipulation of TEMR during cell seeding and maturation via bioprinting while simultaneously maximizing TEMR stability throughout the biofabrication process. This new biomanufacturing strategy not only accelerated the rate of functional recovery, but also eliminated all TEMR failures. In addition, implementation of bioprinting resulted in more physiomimetic skeletal muscle characteristics of repaired muscle tissue.

Double-Bundle Medial Collateral Ligament Reconstruction Improves Anteromedial Rotatory Instability

Background: New techniques have been proposed to better address anteromedial rotatory instability in a medial collateral ligament (MCL)–injured knee that require an extra graft and more surgical implants, which might not be feasible in every clinical setting. Purpose: To investigate if improved resistance to anteromedial rotatory instability can be achieved by using a single-graft, double-bundle (DB) MCL reconstruction with a proximal fixation more anteriorly on the tibia, in comparison with the gold standard single-bundle (SB) MCL reconstruction. Study Design: Controlled laboratory study. Methods: Eight fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic simulator in intact knee, superficial MCL/deep MCL–deficient, and reconstruction states. Three different reconstructions were tested: DB MCL no proximal tibial fixation and DB and SB MCL reconstruction with proximal tibial fixation. Knee kinematics were recorded at 0°, 30°, 60°, and 90° of knee flexion for the following measurements: 8 N·m of valgus rotation (VR), 5 N·m of external tibial rotation, 5 N·m of internal tibial rotation, combined 89 N of anterior tibial translation and 5 N·m of external rotation for anteromedial rotation (AMR) and anteromedial translation (AMT). The differences between each state for every measurement were analyzed with VR and AMR/AMT as primary outcomes. Results: Cutting the superficial MCL/deep MCL increased VR and AMR/AMT in all knee positions except at 90° for VR (P < .05). All reconstructions restored VR to the intact state except at 90° of knee flexion (P < .05). The DB MCL no proximal tibial fixation reconstruction could not restore intact AMR/AMT kinematics in any knee position (P < .05). Adding an anterior-based proximal tibial fixation restored intact AMR/AMT kinematics at ≥30° of knee flexion except at 90° for AMT (P < .05). The SB MCL reconstruction could not restore intact AMR/AMT kinematics at 0° and 90° of knee flexion (P < .05). Conclusion: In this in vitro cadaveric study, a DB MCL reconstruction with anteriorly placed proximal tibial fixation was able to control AMR and AMT better than the gold standard SB MCL reconstruction. Clinical Relevance: In patients with anteromedial rotatory instability and valgus instability, a DB MCL reconstruction may be superior to the SB MCL reconstruction, without causing extra surgical morbidity or additional costs.