| 1. |
|
|
| 2. |
- Eriksson, Sam, et al.
(författare)
-
Laser speckle contrast imaging for intraoperative assessment of liver microcirculation: a clinical pilot study.
- 2014
-
Ingår i: Medical devices (Auckland, N.Z.). - 1179-1470. ; 7, s. 257-261
-
Tidskriftsartikel (refereegranskat)abstract
- Liver microcirculation can be affected by a wide variety of causes relevant to liver transplantation and resectional surgery. Intraoperative assessment of the microcirculation could possibly predict postoperative outcome. The present pilot study introduces laser speckle contrast imaging (LSCI) as a new clinical method for assessing liver microcirculation.
|
|
| 3. |
- Eriksson, Sam, et al.
(författare)
-
Non-invasive imaging of microcirculation: a technology review.
- 2014
-
Ingår i: Medical devices (Auckland, N.Z.). - 1179-1470. ; 7, s. 445-452
-
Forskningsöversikt (refereegranskat)abstract
- Microcirculation plays a crucial role in physiological processes of tissue oxygenation and nutritional exchange. Measurement of microcirculation can be applied on many organs in various pathologies. In this paper we aim to review the technique of non-invasive methods for imaging of the microcirculation. Methods covered are: videomicroscopy techniques, laser Doppler perfusion imaging, and laser speckle contrast imaging. Videomicroscopy techniques, such as orthogonal polarization spectral imaging and sidestream dark-field imaging, provide a plentitude of information and offer direct visualization of the microcirculation but have the major drawback that they may give pressure artifacts. Both laser Doppler perfusion imaging and laser speckle contrast imaging allow non-contact measurements but have the disadvantage of their sensitivity to motion artifacts and that they are confined to relative measurement comparisons. Ideal would be a non-contact videomicroscopy method with fully automatic analysis software.
|
|
| 4. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
-
Bone Conduction Stimulated VEMP Using the B250 Transducer
- 2021
-
Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 14, s. 225-237
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Bone conduction (BC) stimulation is rarely used for clinical testing of vestibular evoked myogenic potentials (VEMPs) due to the limitations of conventional stimulation alternatives. The aim of this study is to compare VEMP using the new B250 transducer with the Minishaker and air conduction (AC) stimulation. Methods: Thirty normal subjects between 20 and 37 years old and equal gender distribution were recruited, 15 for ocular VEMP and 15 for cervical VEMP. Four stimulation conditions were compared: B250 on the mastoid (FM); Minishaker and B250 on the forehead (FZ); and AC stimulation using an insert earphone. Results: It was found that B250 at FM required a statistically significant lower hearing level than with AC stimulation, in average 41 dB and 35 dB lower for ocular VEMP and cervical VEMP, respectively, but gave longer n10 (1.1 ms) and n23 (1.6 ms). No statistical difference was found between B250 at FM and Minishaker at FZ. Conclusion: VEMP stimulated with B250 at FM gave similar response as the Minishaker at FZ and for a much lower hearing level than AC stimulation using insert earphones.
|
|
| 5. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
-
Magnetic resonance imaging investigation of the bone conduction implant - a pilot study at 1.5 Tesla.
- 2015
-
Ingår i: Medical devices (Auckland, N.Z.). - 1179-1470. ; 8, s. 413-23
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this pilot study was to investigate if an active bone conduction implant (BCI) used in an ongoing clinical study withstands magnetic resonance imaging (MRI) of 1.5 Tesla. In particular, the MRI effects on maximum power output (MPO), total harmonic distortion (THD), and demagnetization were investigated. Implant activation and image artifacts were also evaluated.
|
|
| 6. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
-
Robustness and lifetime of the bone conduction implant - a pilot study
- 2019
-
Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 12, s. 89-100
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: The objective of this study was to develop methods for evaluating the mechanical robustness and estimating the lifetime of the novel bone conduction implant (BCI) that is used in a clinical study. The methods are intended to be applicable to any similar device. Materials and methods: The robustness was evaluated using tests originally developed for cochlear implants comprising a random vibration test, a shock test, a pendulum test, and an impact test. Furthermore, magnetically induced torque and demagnetization during magnetic resonance imaging at 1.5 T were investigated using a dipole electromagnet. To estimate the lifetime of the implant, a long-term age-accelerated test was performed. Results: Out of all the tests, the pendulum and the impact tests had the largest effect on the electro-acoustic performance of the BCI implant, even if the change in performance was within acceptable limits (< 20%). In comparison with baseline data, the lower and higher resonance peaks shifted down in frequency by 13% and 18%, respectively, and with a loss in magnitude of 1.1 and 2.0 dB, respectively, in these tests. Conclusion: A complete series of tests were developed, and the BCI passed all the tests; its lifetime was estimated to be at least 26 years for patients who are using the implant for 12 hours on a daily basis.
|
|
| 7. |
- Hakansson, B., et al.
(författare)
-
VEMP using a new low-frequency bone conduction transducer
- 2018
-
Ingår i: Medical Devices-Evidence and Research. - : Informa UK Limited. - 1179-1470. ; 11, s. 301-312
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: A new prototype bone conduction (BC) transducer B250, with an emphasized low-frequency response, is evaluated in vestibular evoked myogenic potential (VEMP) investigations. The aim was to compare cervical (cVEMP) and ocular (oVEMP) responses using tone bursts at 250 and 500 Hz with BC stimulation using the B250 and the conventional B81 transducer and by using air conduction (AC) stimulation. Methods: Three normal subjects were investigated in a pilot study. BC stimulation was applied to the mastoids in cVEMP, and both mastoid and forehead in oVEMP investigations. Results: BC stimulation was found to reach VEMP thresholds at considerably lower hearing levels than in AC stimulation (30-40 dB lower oVEMP threshold at 250 Hz). Three or more cVEMP and oVEMP responses at consecutive 5 dB increasing mastoid stimulation levels were only obtained in all subjects using the B250 transducer at 250 Hz. Similar BC thresholds were obtained for both ipsilateral and contralateral mastoid stimulation. Forehead stimulation, if needed, may require a more powerful vibration output. Conclusion: Viable VEMP responses can be obtained at a considerably lower hearing level with BC stimulation than by AC stimulation. The cVEMP and oVEMP responses were similar when measured on one side and with the B250 attached to both ipsilateral and contralateral mastoids.
|
|
| 8. |
- Håkansson, Bo, 1953, et al.
(författare)
-
The mechanical impedance of the human skull via direct bone conduction implants
- 2020
-
Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 13, s. 293-313
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: The mechanical skull impedance is used in the design of direct bone drive hearing systems. This impedance is also important for the design of skull simulators used in manufacturing, service, and fitting procedures of such devices. Patients and Methods: The skull impedance was measured in 45 patients (25 female and 20 male) who were using percutaneous bone conduction implants (Ponto system or Baha system). Patients were recruited as a consecutive prospective case series and having an average age of 55.4 years (range 18–80 years). Seven patients were treated in Gothenburg, Sweden, and 38 patients in Edmonton, Canada. An impedance head (B&K 8001), driven by an excitation transducer with emphasized low-frequency response, was used to measure the mechanical point impedance with a swept sine from 100 to 10k Hz. Results and Discussion: The skull impedance was found to have an anti-resonance of approximately 150 Hz, with a median maximum magnitude of 4500 mechanical ohms. Below this anti-resonance, the mechanical impedance was mainly mass-controlled corresponding to an effective skull mass of 2.5 kg at 100 Hz with substantial damping from neck and shoulder. Above the anti-resonance and up to 4 kHz, the impedance was stiffness-controlled, with a total compliance of approximately 450n m/N with a small amount of damping. At frequencies above 4 kHz, the skull impedance becomes gradually mass-controlled originating from the mass of the osseointegrated implant and adjacent bone. No significant differences related to gender or skull abnormalities were seen, just a slight dependence on age and major ear surgeries. The variability of the mechanical impedance among patients was not found to have any clinical importance. Conclusion: The mechanical skull impedance of percutaneous implants was found to confirm previous studies and can be used for optimizing the design and test procedures of direct bone drive hearing implants. © 2020 Håkansson et al.
|
|
| 9. |
- Håkansson, Bo, 1953, et al.
(författare)
-
VEMP using a new low-frequency bone conduction transducer
- 2018
-
Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 11, s. 301-312
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: A new prototype bone conduction (BC) transducer B250, with an emphasized low-frequency response, is evaluated in vestibular evoked myogenic potential (VEMP) investigations. The aim was to compare cervical (cVEMP) and ocular (oVEMP) responses using tone bursts at 250 and 500 Hz with BC stimulation using the B250 and the conventional B81 transducer and by using air conduction (AC) stimulation. Methods: Three normal subjects were investigated in a pilot study. BC stimulation was applied to the mastoids in cVEMP, and both mastoid and forehead in oVEMP investigations. Results: BC stimulation was found to reach VEMP thresholds at considerably lower hearing levels than in AC stimulation (30-40 dB lower oVEMP threshold at 250 Hz). Three or more cVEMP and oVEMP responses at consecutive 5 dB increasing mastoid stimulation levels were only obtained in all subjects using the B250 transducer at 250 Hz. Similar BC thresholds were obtained for both ipsilateral and contralateral mastoid stimulation. Forehead stimulation, if needed, may require a more powerful vibration output. Conclusion: Viable VEMP responses can be obtained at a considerably lower hearing level with BC stimulation than by AC stimulation. The cVEMP and oVEMP responses were similar when measured on one side and with the B250 attached to both ipsilateral and contralateral mastoids.
|
|
| 10. |
- Jansson, K. J. F., et al.
(författare)
-
Bone Conduction Stimulated VEMP Using the B250 Transducer
- 2021
-
Ingår i: Medical Devices-Evidence and Research. - 1179-1470. ; 14, s. 225-237
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Bone conduction (BC) stimulation is rarely used for clinical testing of vestibular evoked myogenic potentials (VEMPs) due to the limitations of conventional stimulation alternatives. The aim of this study is to compare VEMP using the new B250 transducer with the Minishaker and air conduction (AC) stimulation. Methods: Thirty normal subjects between 20 and 37 years old and equal gender distribution were recruited, 15 for ocular VEMP and 15 for cervical VEMP. Four stimulation conditions were compared: B250 on the mastoid (FM); Minishaker and B250 on the forehead (FZ); and AC stimulation using an insert earphone. Results: It was found that B250 at FM required a statistically significant lower hearing level than with AC stimulation, in average 41 dB and 35 dB lower for ocular VEMP and cervical VEMP, respectively, but gave longer n10 (1.1 ms) and n23 (1.6 ms). No statistical difference was found between B250 at FM and Minishaker at FZ. Conclusion: VEMP stimulated with B250 at FM gave similar response as the Minishaker at FZ and for a much lower hearing level than AC stimulation using insert earphones.
|
|
| 11. |
|
|
| 12. |
- Jonasson, Aino Fianu, et al.
(författare)
-
Safety and Efficacy of an Oxytocin Gel and an Equivalent Gel but Without Hormonal Ingredients (Vagivital® Gel) in Postmenopausal Women with Symptoms of Vulvovaginal Atrophy : A Randomized, Double-Blind Controlled Study
- 2020
-
Ingår i: Medical Devices. - : DOVE MEDICAL PRESS LTD. - 1179-1470. ; 13, s. 339-347
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: The primary objective was to compare the efficacy of 12 weeks of daily treatment with Aqueous Hypromellose-based vaginal (Vagivital®) gel versus Aqueous Hypromellose-based vaginal gel plus 400 IU oxytocin gel in reducing the severity of the most bothersome vulvovaginal atrophy symptoms (MBS: itching, dysuria, bleeding, and pain/discomfort during vaginal sexual activity) observed at baseline. The secondary objectives were to evaluate the other vulvovaginal atrophy symptoms, vaginal pH, superficial squamous cells, and the safety and tolerability of both gels.Patients and Methods: This double-blind, randomized study evaluated the safety and efficacy of subjects randomly assigned to 12 weeks of daily intravaginal oxytocin gel (n=79) or Aqueous Hypromellose-based vaginal gel (n=78). The efficacy evaluation was performed using data from all included subjects who fulfilled entry criteria.Results: Both treatments induced statistically significant reductions in the severity of the MBS from baseline until 4 weeks (Vagivital mean reduction 0.90, p=0.0000; Oxytocin mean reduction 0.82, p=0.0000) and 12 weeks post baseline (Vagivital mean reduction 1.28, p=0.0000; Oxytocin mean reduction 1.16, p=0.0000), but the reduction of MBS severity was not significantly different between the treatment groups at either time point. No serious adverse events were reported in the Aqueous Hypromellose-based vaginal gel group during the treatment period, but one (breast cancer) was reported in the oxytocin gel group (assessed as unlikely related to the study compound).Conclusion: Significant reductions in the severity of the MBS were seen in both the Aqueous Hypromellose-based vaginal gel and the oxytocin gel groups, but with no significant differences in severity reduction seen between the groups. Both gels were safe and well tolerated. Given the benefits of avoiding the use of hormones, Aqueous Hypromellose-based vaginal gel is an attractive first choice in the treatment of postmenopausal women with vulvovaginal atrophy symptoms.
|
|
| 13. |
- Reinfeldt, Sabine, 1978, et al.
(författare)
-
Nasal sound pressure as objective verification of implant in active transcutaneous bone conduction devices
- 2019
-
Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 12, s. 193-202
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Active transcutaneous bone conduction devices consist of an external audio processor and an internal implant under intact skin. During the surgical procedure, it is important to verify the functionality of the implant before the surgical wound is closed. In a clinical study with the new bone conduction implant (BCI), the functionality of the implant was tested with an electric transmission test, where the output was the nasal sound pressure (NSP) recorded in the ipsilateral nostril. The same measurement was performed in all follow-up visits to monitor the implant's functionality and transmission to bone over time. The objective of this study was to investigate the validity of the NSP method as a tool to objectively verify the implant's performance intraoperatively, as well as to follow-up the implant's performance over time. Design: Thirteen patients with the BCI were included, and the NSP measurement was part of the clinical study protocol. The implant was electrically stimulated with an amplitude-modulated signal generator using a swept sine 0.1-10 kHz. The NSP was measured with a probe tube microphone in the ipsilateral nostril. Results: The NSP during surgery was above the noise floor for most patients within the frequency interval 0.4-5 kHz, showing NSP values for expected normal transmission of a functioning implant. Inter-subject comparison showed large variability, but follow-up results showed only minor variability within each subject. Further investigation showed that the NSP was stable over time. Conclusion: The NSP method is considered applicable to verify the implant's functionality during and after surgery. Such a method is important for implantable devices, but should be simplified and clinically adapted. Large variations between subjects were found, as well as smaller variability in intra-subject comparisons. As the NSP was found to not change significantly over time, stable transmission to bone, and implant functionality, were indicated.
|
|
| 14. |
- Reinfeldt, Sabine, 1978, et al.
(författare)
-
New developments in bone-conduction hearing implants: a review
- 2015
-
Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 8, s. 79-93
-
Tidskriftsartikel (refereegranskat)abstract
- The different kinds of bone-conduction devices (BCDs) available for hearing rehabilitation are growing. In this paper, all BCDs currently available or in clinical trials will be described in categories according to their principles. BCDs that vibrate the bone via the skin are referred to as skin-drive devices, and are divided into conventional devices, which are attached with softbands, for example, and passive transcutaneous devices, which have implanted magnets. BCDs that directly stimulate the bone are referred to as direct-drive devices, and are further divided into percutaneous and active transcutaneous devices; the latter have implanted transducers directly stimulating the bone under intact skin. The percutaneous direct-drive device is known as a bone-anchored hearing aid, which is the BCD that has the largest part of the market today. Because of some issues associated with the percutaneous implant, and to some extent because of esthetics, more transcutaneous solutions with intact skin are being developed today, both in the skin-drive and in the direct-drive category. Challenges in developing transcutaneous BCDs are mostly to do with power, attachment, invasiveness, and magnetic resonance imaging compatibility. In the future, the authors assume that the existing percutaneous direct-drive BCD will be retained as an important rehabilitation alternative, while the transcutaneous solutions will increase their part of the market, especially for patients with bone-conduction thresholds better than 35 dB HL (hearing level). Furthermore, the active transcutaneous direct-drive BCDs appear to be the most promising systems, but to establish more detailed inclusion criteria, and potential benefits and drawbacks, more extensive clinical studies are needed.
|
|
| 15. |
- Samuelsson, Kersti, et al.
(författare)
-
Usability of Norm Values on Results from a Simulator Device and Cognitive Tests in Traffic Medicine
- 2022
-
Ingår i: Medical Devices. - Macclesfield, United Kingdom : Dove medical press Ltd.. - 1179-1470. ; 15, s. 59-70
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Driving is an essential everyday task for most adults, and fitness to continue car-driving after a brain injury/disease is a common issue in rehabilitation settings. There is no consensus on how this assessment should be performed and thus further research and development are of great value. The aim was to study the usability of cut-off values, based on recently developed norm values for a driving simulator device (CyberSiM), as well as cognitive tests, for patients already considered fit-to-drive after a standardized traffic medical investigation.Methods: The study had a retrospective case-control design. Norm results (n = 129) were compared with patient results (n = 126) divided into two age groups (<= 59 years and >= 60 years).Results: from Useful Field of View, Trail Making Test, Nordic Stroke Driver Screening Assessment as well as a simulator device (CyberSiM) were compared. Results: The group of patients considered fit-to-drive after a traffic medicine assessment had worse results on all cognitive tests compared with norms. Results on CyberSiM subtests II and III did not differ from norms. The proportion of patients within suggested cut-off limits (mean +/- 2SD norm) and considered fit to drive (mean +/- 2SD norm) were highest (75-95%) for all three subtests of CyberSiM and for Useful Field of View in both age groups. Conclusion: Availability of norm values in decision on continued driving is of value when interpreting the results of cognitive assessments sensitive to age, but it must be handled with care because many factors are important for individuals ability to drive.
|
|
| 16. |
|
|
| 17. |
- Wretenberg, Per, 1963-, et al.
(författare)
-
Hip joint load in relation to leg length discrepancy
- 2008
-
Ingår i: Medical Devices. - Macclesfield, United Kingdom : Dove Medical Press Ltd.(Dovepress). - 1179-1470. ; 1, s. 13-18
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Leg length discrepancy is common both in healthy subjects and after total hip arthroplasty (THA). Studies that evaluated leg length following THA have demonstrated a notable inconsistency in restoring leg length. The effects concerning joint load during gait is however not well known. The purpose of this study was to use three-dimensional (3D) gait analysis to evaluate joint load during gait with a simulated leg length discrepancy of 2 and 4 cm. Nine healthy subjects without any history of hip injury participated.Method: A 3D gait analysis (Vicon, Motion System, Oxford, England) was performed with 6 cameras and 2 force palates using a standard biomechanical gait model. Hip joint moments of force were calculated for all three degrees of motion freedom. ANOVA for repeated measurements was used for statistical calculations.Results: Abduction peak moment was significantly increased at the short side (P < 0.05) but unaffected on the long side. The adduction moment decreased on the long side between 0 and 4 cm (P < 0.01) but was unaffected on the short side. The internal hip rotation moments were unchanged for both the long and the short side. The external rotation moment was unchanged on the short side and decreased between bare foot and 4 cm on the long side (P < 0.05).Conclusion: A leg length discrepancy of 2 cm or more creates biomechanical changes concerning hip joint load both on the long and the short side and that the effects are larger on the short side. The increased stress may cause problems in the long run.
|
|
| 18. |
- Valdimarsson, Valentinus T., et al.
(författare)
-
Repeat procedures for recurrent colorectal liver metastases : Analysis of long-term liver regeneration and outcome
- 2019
-
Ingår i: Cancer Management and Research. - 1179-1322. ; 11, s. 2617-2622
-
Tidskriftsartikel (refereegranskat)abstract
- Background and aim: Repeat hepatectomy is increasingly performed for the management of recurrent colorectal liver metastases (CRLM). The aim of this study was to evaluate longterm functional liver volume (FLV) after a second hepatic procedure and to measure survival outcome. Methods: In this retrospective cohort study, patients treated for recurrent CRLM in the years 2005-2015 at two liver centers were included. Total FLV was calculated before the first procedure and before and after the second procedure. Overall survival was calculated. Results: Eighty-two patients were identified. The median follow-up was 53 (40-71) months from the first procedure. The median interval between first and second procedure was 13 (8-22) months. The initial FLV was 1584 (1313-1927) mL. The FLV was 1438 (1204-1896) mL after the first procedure and 1470 (1172-1699) mL after the second procedure (P<0.001). After the second procedure, a total of ten patients (12%) had a residual liver volume of less than 75% of the initial liver volume. The 5-year overall survival was 37 (26-54)% after the second procedure. Conclusion: Small changes in FLV were found after two hepatic procedures but with considerable inter-individual variation. Patients selected for a repeated hepatic procedure for recurrent CRLM had an acceptable survival.
|
|
