Optimization of tracheoesophageal fistula model established with T-shaped magnet system based on magnetic compression technique.

BACKGROUND: The magnetic compression technique has been used to establish an animal model of tracheoesophageal fistula (TEF), but the commonly shaped magnets present limitations of poor homogeneity of TEF and poor model control. We designed a T-shaped magnet system to overcome these problems and verified its effectiveness via animal experiments. AIM: To investigate the effectiveness of a T-shaped magnet system for establishing a TEF model in beagle dogs. METHODS: Twelve beagles were randomly assigned to groups in which magnets of the T-shaped scheme (study group, n = 6) or normal magnets (control group, n = 6) were implanted into the trachea and esophagus separately under gastroscopy. Operation time, operation success rate, and accidental injury were recorded. After operation, the presence and timing of cough and the time of magnet shedding were observed. Dogs in the control group were euthanized after X-ray and gastroscopy to confirm establishment of TEFs after coughing, and gross specimens of TEFs were obtained. Dogs in the study group were euthanized after X-ray and gastroscopy 2 wk after surgery, and gross specimens were obtained. Fistula size was measured in all animals, and then harvested fistula specimens were examined by hematoxylin and eosin (HE) and Masson trichrome staining. RESULTS: The operation success rate was 100% for both groups. Operation time did not differ between the study group (5.25 min ± 1.29 min) and the control group (4.75 min ± 1.70 min; P = 0.331). No bleeding, perforation, or unplanned magnet attraction occurred in any animal during the operation. In the early postoperative period, all dogs ate freely and were generally in good condition. Dogs in the control group had severe cough after drinking water at 6-9 d after surgery. X-ray indicated that the magnets had entered the stomach, and gastroscopy showed TEF formation. Gross specimens of TEFs from the control group showed the formation of fistulas with a diameter of 4.94 mm ± 1.29 mm (range, 3.52-6.56 mm). HE and Masson trichrome staining showed scar tissue formation and hierarchical structural disorder at the fistulas. Dogs in the study group did not exhibit obvious coughing after surgery. X-ray examination 2 wk after surgery indicated fixed magnet positioning, and gastroscopy showed no change in magnet positioning. The magnets were removed using a snare under endoscopy, and TEF was observed. Gross specimens showed well-formed fistulas with a diameter of 6.11 mm ± 0.16 mm (range, 5.92-6.36 mm), which exceeded that in the control group (P < 0.001). Scar formation was observed on the internal surface of fistulas by HE and Masson trichrome staining, and the structure was more regular than that in the control group. CONCLUSION: Use of the modified T-shaped magnet scheme is safe and feasible for establishing TEF and can achieve a more stable and uniform fistula size compared with ordinary magnets. Most importantly, this model offers better controllability, which improves the flexibility of follow-up studies.

Development of real-time navigation system for laparoscopic hepatectomy using magnetic micro sensor.

BACKGROUND: We report a new real-time navigation system for laparoscopic hepatectomy (LH), which resembles a car navigation system. MATERIAL AND METHODS: Virtual three-dimensional liver and body images were reconstructed using the "New-VES" system, which worked as roadmap during surgery. Several points of the patient's body were registered in virtual images using a magnetic position sensor (MPS). A magnetic transmitter, corresponding to an artificial satellite, was placed about 40 cm above the patient's body. Another MPS, corresponding to a GPS antenna, was fixed on the handling part of the laparoscope. Fiducial registration error (FRE, an error between real and virtual lengths) was utilized to evaluate the accuracy of this system. RESULTS: Twenty-one patients underwent LH with this system. Mean FRE of the initial five patients was 17.7 mm. Mean FRE of eight patients in whom MDCT was taken using radiological markers for registration of body parts as first improvement, was reduced to 10.2 mm (p = .014). As second improvement, a new MPS as an intraoperative body position sensor was fixed on the right-sided chest wall for automatic correction of postural gap. The preoperative and postoperative mean FREs of 8 patients with both improvements were 11.1 mm and 10.1 mm (p = .250). CONCLUSIONS: Our system may provide a promising option that virtually guides LH.

Remote magnetic navigation versus manual catheter ablation of atrial fibrillation: A single center long-term comparison.

BACKGROUND: Data comparing remote magnetic catheter navigation (RMN) with manual catheter navigation (MCN) ablation of atrial fibrillation (AF) is lacking. The aim of the present prospective observational study was to compare the outcome of RMN versus (vs.) MCN ablation of AF with regards to AF recurrence. METHODS: The study comprised 667 consecutive patients with a total of 939 procedures: 287 patients were ablated using RMN, 380 using MCN. RESULTS: There was no significant difference between the groups at baseline. After 2.3 ± 2.3 years of follow-up, 23% of the patients in the MCN group remained free of AF recurrence compared to 13% in the RMN group (p < .001). After analysis of 299 repeat ablations (133 MCN, 166 RMN) there was a significantly higher reconnection rate of pulmonary veins after RMN ablation p < .001). In multivariable Cox-regression analysis, RMN ablation was an independent risk factor for AF recurrence besides age, persistent AF, number of isolated pulmonary veins, and left atrial diameter. Procedure time, radiofrequency application time and total number of ablation points were higher in the RMN group. Total fluoroscopy time and total fluoroscopy dose were significantly lower for RMN. Complication rates did not differ between groups (p = .842), although the incidence of significant pericardial effusion was higher in the MCN group (seven cases vs. three in RMN group). CONCLUSIONS: In our study the AF recurrence rate and pulmonary vein reconnection rate is higher after RMN ablation with a similar complication rate but reduced probability of pericardial effusion when compared to MCN.

Endoscopy-assisted magnetic navigation of biohybrid soft microrobots with rapid endoluminal delivery and imaging.

High-precision delivery of microrobots at the whole-body scale is of considerable importance for efforts toward targeted therapeutic intervention. However, vision-based control of microrobots, to deep and narrow spaces inside the body, remains a challenge. Here, we report a soft and resilient magnetic cell microrobot with high biocompatibility that can interface with the human body and adapt to the complex surroundings while navigating inside the body. We achieve time-efficient delivery of soft microrobots using an integrated platform called endoscopy-assisted magnetic actuation with dual imaging system (EMADIS). EMADIS enables rapid deployment across multiple organ/tissue barriers at the whole-body scale and high-precision delivery of soft and biohybrid microrobots in real time to tiny regions with depth up to meter scale through natural orifice, which are commonly inaccessible and even invisible by conventional endoscope and medical robots. The precise delivery of magnetic stem cell spheroid microrobots (MSCSMs) by the EMADIS transesophageal into the bile duct with a total distance of about 100 centimeters can be completed within 8 minutes. The integration strategy offers a full clinical imaging technique-based therapeutic/intervention system, which broadens the accessibility of hitherto hard-to-access regions, by means of soft microrobots.

Hydrophilic molecularly imprinted polymers functionalized magnetic carbon nanotubes for selective extraction of cyclic adenosine monophosphate from winter jujube.

In this work, a green strategy was developed to prepare molecularly imprinted polymers functionalized magnetic carbon nanotubes in aqueous phase under mild conditions for cyclic adenosine monophosphate. Thanks to water solubility of chitosan, a natural polysaccharide which is rich in amino and hydroxyl groups, provided the feasibility to synthesize the green molecularly imprinted polymers for water soluble template in aqueous media. Coupled with high-performance liquid chromatography, the method exhibited a short equilibrium time (6 min), high adsorption capacity (22.42 µg/mg), high magnetic susceptibility, and good selectivity to template molecule with the imprinting factor of 2.94. A good linearity in the range of 0.020-3.0 mg/mL for target was obtained with a correlation coefficient of 0.9998. The limit of detection (signal-to-noise ratio = 3) and limit of quantitation (signal-to-noise ratio = 10) of the magnetic solid phase extraction method for cyclic adenosine monophosphate were 5 and 15 ng/mg, respectively. And the practical application of chitosan-based molecularly imprinted polymers as adsorbent to isolate and determine cyclic adenosine monophosphate in real natural samples (winter jujube) was demonstrated.

Single-molecule multiplexed profiling of protein-DNA complexes using magnetic tweezers.

Epigenetics, such as the dynamic interplay between DNA methylation and demethylation, play diverse roles in critical cellular events. Enzymatic activity at CpG sites, where cytosines are methylated or demethylated, is known to be influenced by the density of CpGs, methylation states, and the flanking sequences of a CpG site. However, how the relevant enzymes are recruited to and recognize their target DNA is less clear. Moreover, although DNA-binding epigenetic enzymes are ideal targets for therapeutic intervention, these targets have been rarely exploited. Single-molecule techniques offer excellent capabilities to probe site-specific protein-DNA interactions and unravel the dynamics. Here, we develop a single-molecule approach that allows multiplexed profiling of protein-DNA complexes using magnetic tweezers. When a DNA hairpin with multiple binding sites is unzipping, strand separation pauses at the positions bound by a protein. We can thus measure site-specific binding probabilities and dissociation time directly. Taking the TET1 CXXC domain as an example, we show that TET1 CXXC binds multiple CpG motifs with various flanking nucleotides or different methylation patterns in an AT-rich DNA. We are able to establish for the first time, at nanometer resolution, that TET1 CXXC prefers G/C flanked CpG motif over C/G, A/T, or T/A flanked ones. CpG methylation strengthens TET1 CXXC recruitment but has little effect on dissociation time. Finally, we demonstrate that TET1 CXXC can distinguish five CpG clusters in a CpG island with crowded binding motifs. We anticipate that the feasibility of single-molecule multiplexed profiling assays will contribute to the understanding of protein-DNA interactions.

Microfluidic chip for graduated magnetic separation of circulating tumor cells by their epithelial cell adhesion molecule expression and magnetic nanoparticle binding.

The enumeration of circulating tumor cells (CTCs) in the peripheral bloodstream of metastatic cancer patients has contributed to improvements in prognosis and therapeutics. There have been numerous approaches to capture and counting of CTCs. However, CTCs have potential information beyond simple enumeration and hold promise as a liquid biopsy for cancer and a pathway for personalized cancer therapy by detecting the subset of CTCs having the highest metastatic potential. There is evidence that epithelial cell adhesion molecule (EpCAM) expression level distinguishes these highly metastatic CTCs. The few previous approaches to selective CTC capture according to EpCAM expression level are reviewed. A new two-stage microfluidic device for separation, enrichment and release of CTCs into subpopulations sorted by EpCAM expression level is presented here. It relies upon immunospecific magnetic nanoparticle labeling of CTCs followed by their field- and flow-based separation in the first stage and capture as discrete subpopulations in the second stage. To fine tune the separation, the magnetic field profile across the first stage microfluidic channel may be modified by bonding small Vanadium Permendur strips to its outer walls. Mathematical modeling of magnetic fields and fluid flows supports the soundness of the design.

Using magnetic particle imaging systems to localize and guide magnetic hyperthermia treatment: tracers, hardware, and future medical applications.

Magnetic fluid hyperthermia (MFH) treatment makes use of a suspension of superparamagnetic iron oxide nanoparticles, administered systemically or locally, in combination with an externally applied alternating magnetic field, to ablate target tissue by generating heat through a process called induction. The heat generated above the mammalian euthermic temperature of 37°C induces apoptotic cell death and/or enhances the susceptibility of the target tissue to other therapies such as radiation and chemotherapy. While most hyperthermia techniques currently in development are targeted towards cancer treatment, hyperthermia is also used to treat restenosis, to remove plaques, to ablate nerves and to alleviate pain by increasing regional blood flow. While RF hyperthermia can be directed invasively towards the site of treatment, non-invasive localization of heat through induction is challenging. In this review, we discuss recent progress in the field of RF magnetic fluid hyperthermia and introduce a new diagnostic imaging modality called magnetic particle imaging that allows for a focused theranostic approach encompassing treatment planning, treatment monitoring and spatially localized inductive heating.

Synergistic use of electroosmotic flow and magnetic forces for nucleic acid extraction.

Nucleic acid sample preparation is essential for biological sample-based diagnostics. It is crucial that diagnostic tests be both specific and sensitive as to provide the most accurate diagnosis possible. Inefficient sample preparation can hinder the specificity and sensitivity of these tests since carryover contaminants can inhibit downstream processes, such as amplification. Microfluidic devices have been used previously to extract nucleic acids from a biological sample due to lower reagent volumes and ease of use. A novel microfluidic chip has been designed for nucleic acid sample preparation which combines electroosmotic flow and magnetic bead-based extraction to isolate DNA from a plasma sample. A steady electric field was incorporated into the microfluidic chip design, which when combined with a glass clover slip and a voltage differential, creates electroosmotic flow. With the goal of isolating nucleic acids into a clean, inhibitor free solution, the electroosmotic flow is the driving force and separation mechanism purifying the DNA sample captured on magnetic beads in the microfluidic chip system. Carryover volume, or the volume of unwanted sample contaminants that accompany the nucleic acids into the final elution buffer, was minimized to 0.22 ± 0.03%. In combination with magnetic bead based nucleic acid extraction techniques, a 15% increase in DNA extraction yield is reported for the microfluidic chip with the voltage applied versus without. Although the literature on nucleic acid separation in microfluidic chips is abundant, this is the first to combine microfluidic chip design, magnetic bead-based isolation and electroosmotic flow.

Dynamic Analysis of Sphere-Like Iron Particles Based Magnetorheological Damper for Waveform-Generating Test System.

In this study, a new double pulse waveform-generating test system with an integrated magnetorheological (MR) damper is proposed. Since the total shear stress of MR fluid can be varied according to the shape of particles, sphere-like iron particles-based MR fluid is filled into the MR damper. The test system consists of a velocity generator, three masses (impact, test, and dummy), a spring, and an MR damper. To tune the double pulse waveform profile, a damping force model is constructed to determine the fundamental parameters of the simulator. Then, the first and second shock waveform profiles are analyzed to solve the governing equation of motions representing the damping force and velocity. The mathematical model of the MR damper is formulated and applied to a simulator with a graphical user interface programmed using MATLAB. The effectiveness of the proposed simulator-featuring controllable MR damper is demonstrated by comparing the simulation and experimental results.

Single-port robotic-assisted laparoscopic sacrocolpopexy with magnetic retraction: first experience using the SP da Vinci platform.

The purpose of this study was to describe technical considerations and first outcomes from a single-port robotic-assisted sacrocolpopexy (RSC) using the da Vinci SP platform (Intuitive Surgical, Sunnyvale, CA) and the Levita™ Magnetic Surgical System (San Mateo, CA, USA), a novel magnetic retraction system. Three females with pelvic organ prolapse elected to undergo RSC using the da Vinci SP platform. The supraumbilical incision length was 25 mm through which SP trocar was placed. A 12-mm assistant port was placed in the right upper quadrant. The external magnet was attached to the left side of the bed and used for bowel and bladder retraction. We then proceeded by duplicating the steps of our approach for a RSC performed using a multi-port robotic platform with necessary modifications given the SP approach. Intra-operative outcomes and peri-operative outcomes were collected and reported. The patients were women of 64, 66 and 73 years of age with BMI of 22, 25, and 34, respectively, and POP-Q stage III and IV prolapse. The RSC was performed between 198 and 247 min, estimated blood loss was 10-50 cc, and there were no complications. All patients were discharged home on post-operative day 1. All patients were doing well 1 month out with resolution of bulge symptoms. To our knowledge, this represents the first case series of robotic, magnetic-assisted sacrocolpopexies using the da Vinci SP platform and the Levita™ Magnetic Surgical System. It appears to be a safe and feasible approach, but long-term comparative studies will be necessary to assess functional outcomes.

Development and application of DNA-aptamer-coupled magnetic beads and aptasensors for the detection of Cryptosporidium parvum oocysts in drinking and recreational water resources.

Environmentally stable and disinfectant-resistant oocysts of Cryptosporidium spp. shed in the feces of infected humans and animals frequently contaminate water resources and are subsequently spread via potable and recreational waters. The current monoclonal-antibody-based methods for detecting them in water are slow, labor-intensive, and demand skills to interpret the results. We have developed DNA-aptamer-based aptasensors, coupled with magnetic beads, to detect and identify the oocysts of C. parvum for monitoring recreational and drinking water sources. A sensitive and specific electrochemical aptasensor (3'-biotinylated R4-6 aptamer) was used as a secondary ligand to bind the streptavidin-coated magnetic beads. This was incorporated into a probe using gold nanoparticle modified screen-printed carbon electrodes. Square wave voltammetry allowed for specific recognition of C. parvum oocysts. The aptamer-coated probes had an oocyst detection limit of 50. It did not bind to the cysts of Giardia duodenalis, another common waterborne pathogen, thus indicating its high specificity for the target pathogen. The system could successfully detect C. parvum oocysts in spiked samples of the raw lake and river waters. Therefore, the combined use of the aptasensor and magnetic beads has the potential to monitor water quality for C. parvum oocysts in field samples without relying on monoclonal antibodies and skill-demanding microscopy.

Magnetically Controlled Growing Rods in Treatment of Early-Onset Scoliosis: A Single Center Study With a Minimum of 2-Year-Follow up and Preliminary Results After Converting Surgery.

STUDY DESIGN: Case series. OBJECTIVE: To evaluate complications and radiographic parameters after magnetically controlled growing rod (MCGR) index surgery (IS), during lengthening and following converting surgery (CS) with a minimum of 2-year follow up (FU). SUMMARY OF BACKGROUND DATA: MCGR are maintaining skeletal growth in treatment of early onset scoliosis (EOS). There is no data regarding correction potential after CS available. METHODS: Twenty-four cases were included. Two patients with rib and pelvic hook fixation instead of pedicle screws and three patients with previous spinal surgery were excluded from radiographic analysis. RESULTS: Twenty-one patients received grade 3 or 4 in Classification of Early-Onset-Scoliosis (C-EOS) for main curve severity. The kyphotic modifiers (-) were given to seven and (+) to seven patients. Mean age at IS was 10.5 ±â€Š2.4 years with a mean FU time of 42.3 ±â€Š11.3 months. Deformity correction was only achieved during IS (46%) and CS (36%). During MCGR treatment a 5° loss of correction seen, while 25 mm of T1-S1 length was gained during the lengthening period. An overall average lengthening of 1.6 mm per lengthening procedure was achieved. Possibility to gain length during distractions decreases over time. No major failure of the distraction mechanism was observed, only 16 lengthening procedures failed within a total of 264 lengthening procedures. A total of 19 revision surgeries in 10 patients were observed. Four patients received more than one revision surgery. CONCLUSION: Applying MCGR results in a revision rate of 0.23 per patient and per one FU year, while making further lengthening procedures obsolete compared with conventional growing rod techniques. Correction of major curve is possible during IS und CS. The law of diminishing returns applies during the period of lengthening. LEVEL OF EVIDENCE: 4.

Evaluation of a Ferromagnetic Marker Technology for Intraoperative Localization of Nonpalpable Breast Lesions.

OBJECTIVE: The purpose of this study was to evaluate the magnetic occult lesion localization instrument (MOLLI) system that involves implantation of a small, ferromagnetic marker to guide surgical excision of nonpalpable breast lesions. Characterization of the system was undertaken as part of what is, to our knowledge, the first study to assess the MOLLI system. MATERIALS AND METHODS: The MOLLI system consists of a handheld probe that can detect the position and distance of an implanted magnetic marker. The system presents the surgeon with an accurate assessment of lesion location and depth measurement for precise 3D localization. The marker is implanted under ultrasound or mammographic guidance at any time before the surgical procedure and requires no special precautions. Experimental analysis focused on characterization of the following aspects of the MOLLI system: visualization of the marker under imaging, 3D detection of the magnetic marker, spatial resolution of the probe to detect markers placed in close proximity, and the effect of signal interference on system performance. RESULTS: The MOLLI system can reliably detect mean (± SD) marker depths up to 53 ± 8.56 mm from the probe. Bracketing large lesions or localizing multiple lesions can be accomplished by placing markers as close as 10 mm apart, at depths of up to 42 mm. The biologically inert MOLLI marker is readily visible under ultrasound and mammographic guidance, and it is differentiable from radiologic clips. The effect of surgical instruments on MOLLI functioning is minimal and does not impact system accuracy or reliability. CONCLUSION: The MOLLI system offers an accurate and efficient alternative lesion localization method for nonpalpable breast lesions.

Kinematics and shock attenuation during a prolonged run on the athletic track as measured with inertial magnetic measurement units.

BACKGROUND: Tibial stress fractures are common running related injury and their etiology may include biomechanical factors like impact forces, shock attenuation, lower limb kinematics and how these factors are influenced by intense or prolonged running. Inertial-magnetic measurement units (IMUs) have recently emerged as an alternative to motion capture but their use to date was mostly limited to segmental and joint motion. RESEARCH QUESTION: The present study sought to examine the effects of a prolonged run on shock attenuation, peak tibial and sacral acceleration (PTA, PSA), and lower limb kinematics using IMUs. METHODS: Ten trained male runners (31 +/- 5 yr, 183 +/- 3 cm, 76 +/- 9 kg) performed a twenty-minute prolonged run on an athletic track at estimated lactate threshold speed. Eight IMUs, positioned over the feet, lower and uppers legs, sacrum and sternum, were used to calculate joint kinematics, impact parameters and shock attenuation in the time domain (1-(PSA/PTA)*100). RESULTS: PTA increased while PSA and shock attenuation did not change following the prolonged run. Hip and knee flexion at midstance decreased. Vertical lower leg angle at initial contact did not change. CONCLUSION: By using IMUs, it was shown that a prolonged run at estimated lactate threshold speed had significant effects on kinematics and tibial acceleration parameters. By modifying hip and knee joint kinematics during stance, the body was able to maintain sacral acceleration possibly by shifting from active shock attenuation to more passive mechanisms. SIGNIFICANCE: The present study shows that inertial sensors can be used in outdoor running to measure joint kinematics and kinetic parameters like PTA, PSA and shock attenuation simultaneously. The results of this study show new insights into how the body copes with impact during prolonged running.

Evaluation of an automated magnetic bead-based DNA extraction and real-time PCR in fecal samples as a pre-screening test for detection of Echinococcus multilocularis and Echinococcus canadensis in coyotes.

Efficient and sensitive diagnostic tools are essential for the study of the eco-epidemiology of Echinococcus species. We evaluated an automated magnetic bead-based DNA extraction commercial kit followed by qPCR (MB-qPCR), for the detection of Echinococcus multilocularis and Echinococcus canadensis in coyote (Canis latrans) fecal samples. The diagnostic sensitivity was determined by validating the method against the scraping, filtration, and counting technique (SFCT) for samples collected in Canada. From the 60 samples tested, 27 out of 31 SFCT positives samples for Echinococcus cestodes were positive in the MB-qPCR for E. multilocularis, with a sensitivity of 87.1% (95% CI 70.2 to 96.4%). Two samples were also positive for E. canadensis in the MB-qPCR and confirmed by morphological identification of adult worms. The agreement of the MB-qPCR and the SFCT was statistically significant with a kappa value of 0.67 (95% CI 0.48-0.85; p value < 0.001). The magnetic bead-based DNA extraction followed by qPCR proved to have a sensitivity comparable to the SFCT to detect E. multilocularis. Although the diagnostic sensitivity for E. canadensis was not estimated, MB-qPCR identified E. canadensis cases previously overlooked when using SFCT. We propose a combination of molecular and morphological identification using the MB-qPCR and the SFCT to detect both parasites, allowing for a more efficient large-scale surveillance, and detecting co-infections of Echinococcus species that can be difficult to identify when only based on morphology.

Magnetic-assisted robotic surgery: initial case series of reduced-port robotic prostatectomy.

Minimally invasive radical prostatectomy has rapidly been adopted as the primary means of surgical intervention for prostate cancer. Intraoperative tissue retraction relies on either gravity (via positioning) or use of additional ports and instrumentation. We report the use of a novel trocar-less magnetic retractor system to aid with tissue retraction. Three patients underwent robotic-assisted radical prostatectomy in the treatment of prostatic adenocarcinoma at a single tertiary care institution. All surgeries utilized the Levita™ Magnetic Surgical System (San Mateo, CA) without the use of a fourth robotic arm. The magnetic grasper was used to manipulate the bowel, peritoneum, seminal vesicles, and prostatic capsule. Demographic, pre-operative, and perioperative information were collected. No cases required placement of any additional ports. No intraoperative or immediate post-operative complications occurred. No tissue tearing or subjective tissue damage was noted by placement or removal of the magnetic retractor. Mean operative time was 216 ± 17 min and mean blood loss was 333 ± 57 mL. All patients were discharged to home on post-operative day 1. Robotic prostatectomy utilizing a magnetically anchored tissue grasper appears to be safe and effective while reducing the number of ports (fourth robotic arm) needed. Further investigation is warranted.

Does Decreased Surgical Stress Really Improve the Psychosocial Health of Early-onset Scoliosis Patients?: A Comparison of Traditional Growing Rods and Magnetically-controlled Growing Rods Patients Reveals Disappointing Results.

STUDY DESIGN: Cross-sectional case-control study. OBJECTIVE: Compare psychosocial profile of magnetically-controlled growing rod (MCGR) patients to traditional-growing rod (TGR) with an array of psychiatric tools, expecting improvement in MCGR due to decreased number of surgical procedures. SUMMARY OF BACKGROUND DATA: TGR treatment has had positive clinical and radiographic results; however, upward of 10 surgical sessions and high complication rates have called into question the quality of life of these children. Improvement with the introduction of the MCGR is expected. METHODS: GR patients with minimum of 2-years follow-up were recruited. None had neurological conditions. All underwent testing with the Wechsler Intelligence Scale for Children-Revised, and only those in the normal range were included. Patients filled out questionnaires with mental health professionals to measure psychosocial status. MCGR patients' results were compared to TGR patients. RESULTS: Twenty-seven patients met criteria (10 MCGR, 17 TGR): average age at enrollment 11.8 years (range 5.9-17). MCGR group was significantly younger (9.1 vs. 13.3 yr) and had significantly shorter follow-up (45.6 vs. 82.8 mo) (P < 0.05). TGR patients underwent an average of 16 surgical procedures, MCGR an average of 1.5 (including complications, P < 0.05). Age at index surgery (6 yr), preoperative and postoperative major curve magnitudes (60°, 40° respectively) were statistically similar.There was no difference in current psychiatric diagnoses between the groups. MCGR patients scored worse than TGR patients in general functionality domains. TGR patients showed increased functionality and prosocial scores with increased number of procedures. This effect was not observed in MCGR. CONCLUSIONS: The expected improvement in psychosocial status with the MCGR was not observed at a 31.6-month-follow-up. It appears that provided the patient spends enough time in the treatment process to notice benefit and does not experience major complications, noninvasiveness of lengthening procedures does not show up as an advantage with the psychosocial tools utilized in this study. LEVEL OF EVIDENCE: 3.

Troponin T release comparing manually or magnetically guided radiofrequency ablation for AVNRT- a MAGMA AVNRT substudy.

OBJECTIVES: Catheter ablation is regarded as first-line therapy for symptomatic atrioventricular nodal reentry tachycardia (AVNRT). Ablation induces intended myocardial damage and the extent of myocardial damage may differ between ablation methods. The objective of this MAGMA AVNRT(NCT00875914) substudy was to compare high-sensitive cardiac troponin T (hs-cTnT) levels as a surrogate marker for myocardial damage after manually guided (MAN) AVNRT ablation versus AVNRT ablation using remote magnetic navigation (RMN). DESIGN: In total, 70 patients (mean age 44 ± 14 years, 26% male) undergoing catheter ablation for AVNRT in the MagMa-AVNRT-Trial were randomized to remote magnetic navigation (n = 34, 49%) or manually guided catheter ablation (n = 36, 51%). hs-cTnT was measured the day after the procedure. RESULTS: The median follow-up time was 6.2 ± 1.1 years. Acute success was 100% in both groups. hs-cTnT release was significantly lower in the remote magnetic navigation group (52 ng/L versus 95 ng/L, p < .01), even though the ablation time was longer and number of applications was higher with remote magnetic navigation (4.2 min vs 2.8 min, p = .017; 4.9 vs 3.3 applications, p = .01). hs-cTnT released per minute ablation time was also lower with remote magnetic navigation (12 ng/L versus 34 ng/L, p < .01). Both groups exhibited similar clinical long-term follow up regarding recurrence and complications. CONCLUSION: Remote magnetic navigation controlled catheter ablation of AVNRT has similar clinical outcome, but leads to less hs-cTnT release than manually guided catheter ablation. This might correspond to less unintended myocardial damage with RMN, which might be advantageous in complex ablation procedures.