Thermal Effects during Bone Preparation and Insertion of Osseointegrated Transfemoral Implants

Background: The preparation of bone for the insertion of an osseointegrated transfemoral implant and the insertion process are performed at very low speeds in order to avoid thermal damages to bone tissue which may potentially jeopardize implant stability. The aim of this study was to quantify the temperature increase in the femur at different sites and insertion depths, relative to the final implant position during the stepwise implantation procedure. Methods: The procedure for installation of the osseointegrated implant was performed on 24 femoral specimens. In one specimen of each pair, the surgery was performed at the clinically practiced speed, while the speed was doubled in the contralateral specimen. Six 0.075 mm K fine gauge thermocouples (RS Components, Sorby, UK) were inserted into the specimen at a distance of 0.5 mm from the final implant surface, and six were inserted at a distance of 1.0 mm. Results: Drilling caused a temperature increase of <2.5 °C and was not statistically significantly different for most drill sizes (0.002 < p < 0.845). The mean increase in temperature during thread tapping and implant insertion was <5.0 °C, whereas the speed had an effect on the temperature increase during thread tapping. Conclusions: Drilling is the most time-consuming part of the surgery. Doubling the clinically practiced speed did not generate more heat during this step, suggesting the speed and thus the time- and cost-effectiveness of the procedure could be increased. The frequent withdrawal of the instruments and removal of the bone chips is beneficial to prevent temperature peaks, especially during thread tapping.

Longitudinal high-resolution imaging through a flexible intravital imaging window

Intravital microscopy (IVM) is a powerful technique that enables imaging of internal tissues at (sub)cellular resolutions in living animals. Here, we present a silicone-based imaging window consisting of a fully flexible, sutureless design that is ideally suited for long-term, longitudinal IVM of growing tissues and tumors. Crucially, we show that this window, without any customization, is suitable for numerous anatomical locations in mice using a rapid and standardized implantation procedure. This low-cost device represents a substantial technological and performance advance that facilitates intravital imaging in diverse contexts in higher organisms, opening previously unattainable avenues for in vivo imaging of soft and fragile tissues.

Artificial lens replacement in own experiences. What determines the success of this procedure?

The article describes the author’s experiences related to the replacement of an artificial lens with a different model. Reasons for the procedure are described and attention is paid to the stages of lens removal that may affect the final result of the procedure. Lens replacement procedures were performed by one surgeon in the period from one month to over 6 years from the initial implantation procedure. Calcification, glistening and subsequent opacification of the artificial lens are among the main reasons for removing an artificial lens after several years. Removal of the lens in a short time, up to 15 months, resulted from the desire to see without glasses to far and near distances, the presence of a residual defect, and the quality of vision unacceptable to the patient related to the implantation of a premium class lens. The presence of secondary cataract greatly facilitates the lens replacement process.

A study of probable benefit of a bioresorbable polymer scaffold for safety and neurological recovery in patients with complete thoracic spinal cord injury: 6-month results from the INSPIRE study

OBJECTIVEThe aim of this study was to evaluate whether the investigational Neuro-Spinal Scaffold (NSS), a highly porous bioresorbable polymer device, demonstrates probable benefit for safety and neurological recovery in patients with complete (AIS grade A) T2–12 spinal cord injury (SCI) when implanted ≤ 96 hours postinjury.METHODSThis was a prospective, open-label, multicenter, single-arm study in patients with a visible contusion on MRI. The NSS was implanted into the epicenter of the postirrigation intramedullary spinal cord contusion cavity with the intention of providing structural support to the injured spinal cord parenchyma. The primary efficacy endpoint was the proportion of patients who had an improvement of ≥ 1 AIS grade (i.e., conversion from complete paraplegia to incomplete paraplegia) at the 6-month follow-up visit. A preset objective performance criterion established for the study was defined as an AIS grade conversion rate of ≥ 25%. Secondary endpoints included change in neurological level of injury (NLI). This analysis reports on data through 6-month follow-up assessments.RESULTSNineteen patients underwent NSS implantation. There were 3 early withdrawals due to death, which were all determined by investigators to be unrelated to the NSS or the implantation procedure. Seven of 16 patients (43.8%) who completed the 6-month follow-up visit had conversion of neurological status (AIS grade A to grade B [n = 5] or C [n = 2]). Five patients showed improvement in NLI of 1 to 2 levels compared with preimplantation assessment, 3 patients showed no change, and 8 patients showed deterioration of 1 to 4 levels. There were no unanticipated or serious adverse device effects or serious adverse events related to the NSS or the implantation procedure as determined by investigators.CONCLUSIONSIn this first-in-human study, implantation of the NSS within the spinal cord appeared to be safe in the setting of surgical decompression and stabilization for complete (AIS grade A) thoracic SCI. It was associated with a 6-month AIS grade conversion rate that exceeded historical controls. The INSPIRE study data demonstrate that the potential benefits of the NSS outweigh the risks in this patient population and support further clinical investigation in a randomized controlled trial.Clinical trial registration no.: NCT02138110 (clinicaltrials.gov)

Analysis of the antibacterial properties of polycaprolactone modified with graphene, bioglass and zinc-doped bioglass

Purpose: Innovative biomedical filaments for 3D printing in the form of short and biodegradable composite sticks modified with various additives were used to prepare biomaterials for further nasal implants. As the respiratory tract is considered to be potentially exposed to contamination during the implantation procedure there is a need to modify the implant with an antibacterial additives. The purpose of this work was to analyze the effect of biodegradable polymer – polycaprolactone (PCL) modification with various additives on its antibacterial properties. Methods: PCL filament modified with graphene (0.5, 5, 10% wt.), bioglass (0.4% wt.) and zinc-doped bioglass (0.4% wt.) were used to print spatial biomaterials using FDM 3D printer. Pure polymer biomaterials without additives were used as reference samples. The key task was to assess the antimicrobial impact of the prepared biomaterials against the following microorganisms: Staphylococcus aureus ATCC 25293, Escherichia coli ATCC 25922, Candida albicans ATCC 10231. Results: The research results point to a significant antibacterial efficacy of the tested materials against S. aureus and C. albicans, which, however, seems to decrease with increasing graphene content in the filaments. A complete lack of antibacterial efficacy against E. coli was determined. Conclusions: The tested biomaterials have important antibacterial properties, especially against C. albicans. The obtained results showed that biomaterials made of modified filaments can be successfully used in implantology, where a need to create temporary tissue scaffolds occurs.

A randomised, double-blind, controlled trial on patients undergoing cardiac implantable electronic device implantation with local anaesthesia and sedation with and without pectoral nerve block

Background Implantation of cardiac implantable electronic devices (CIED) are generally carried out with local anaesthesia (LA) and sedation. However, peri-procedural hypoxaemia and hypotension are well recognised complications of this technique primarily due to sedation effect. The pectoral nerves block (PECs) targets the lateral and median pectoral nerves at interfascial plane between pectoralis major and minor muscles. This technique potentially lower sedation usage and therefore lower sedation-related complications. There is, however, no randomised study to date comparing CIED procedure with and without PECs block. Methods We randomly assigned 64 patients undergoing CIED implantation procedure with LA (subcutaneous lignocaine 1%) and sedation (intermittent bolus of intravenous midazolam and fentanyl according to pain score) with (32 patients) and without (32 patients) PECs. Those received PECs with be given 10 mls of 0.25% ropivacaine. Primary endpoint was total dose of sedation used. Secondary endpoints were perioperative incidence of hypoxia, hypotension and hypopnea, perioperative pain scores, proceduralists' and patients' satisfaction scores. Results Overall, majority were male (64.1%), mean age of 67.9±10.7 years, mean BMI of 25.7±5.5 kg/m2 and mean lignocaine 1% dosage was 15.3±3.1mL. Compare to those with and without PECs, there was no significant difference in baseline characteristics. The mean fentanyl [25.3±25.0 mcg (95% CI: 16.3–34.3) vs 32.2±26.7 mcg (95% CI: 22.6–41.8), p=0.29] and midazolam dosage [0.7±0.7mg (95% CI: 0.4–0.9) vs 0.8±0.8 (95% CI: 0.6±1.1), p=0.36] were trended lower in PECs compared to without PECs. PECs group had lower pain score at recovery (OR: 1.7, 95% CI: 0.38–7.93, p=0.48). Proceduralists' and patients' satisfaction score were trended higher in PECs compare to non-PECs group. There was no hypoxia, hypotension or hypopnea in both groups. Conclusion Patients underwent CIEDs implantation procedure with PECs received lower sedation dosage and lower periprocedure pain score as compare to non-PECs group. Satisfaction score for both proceduralists and patients were trended higher in PECs group compare to non-PECs group. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): Changi General Hospital Research Grant