PURPOSE: Subpectoral biceps tenodesis is a widely used surgical technique to relieve pain and restore function in the shoulder by securing the long head of the biceps tendon. This study aimed to evaluate the mechanical performance of three fixation techniques using cortical button, interference screw and keyhole methods by assessing their strength, durability and strain distribution, incorporating the novel application of digital image correlation (DIC). METHODS: Thirty fresh porcine bone-tendon specimens were allocated evenly among the fixation techniques. Biomechanical testing involved cyclic axial loading (10-100 N) for 500 cycles, followed by load-to-failure testing using a universal testing machine. DIC analysis assessed strain distribution around the bone drill site. Statistical comparisons of displacement, load-to-failure and strain patterns were performed. RESULTS: Cortical button fixation demonstrated the highest average load-to-failure at 353 ± 45 N, with all specimens completing 500 cycles and showing the least variability. In comparison, interference screw fixation had the lowest average load-to-failure (271 ± 71 N) with two failures occurring before 500 cycles, and the keyhole technique showed intermediate performance at 319 ± 45 N, also with two early failures. Cyclic displacement after 500 cycles was lowest for the interference screw (3.16 ± 0.52 mm), followed by the keyhole (11.51 ± 2.08 mm), and highest for the cortical button (13.84 ± 1.90 mm). Displacement range after 500 cycles was also lowest in the interference screw group (0.62 ± 0.05 mm), compared to the cortical button (0.88 ± 0.07 mm) and keyhole (0.91 ± 0.23 mm). DIC revealed the highest maximum first principal strain around cortical button fixation (0.21%), followed by interference screw (0.16%) and keyhole (0.13%). CONCLUSION: Cortical button fixation demonstrated the highest load-to-failure and the lowest variability, indicating mechanical reliability. The interference screw and keyhole techniques showed comparable load-to-failure values and cyclic displacement but exhibited greater variability. DIC analysis revealed higher localized strain around the cortical button fixation, whereas the interference screw and keyhole techniques displayed more evenly distributed strain. LEVEL OF EVIDENCE: Level V.

• Klíčová slova
• biceps tenodesis, cortical button, digital image correlation, interference screw, keyhole technique, subpectoral tenodesis,
• Publikační typ
• časopisecké články MeSH

Injuries of pectoralis major (PM) muscle are among rare muscle injuries. Due to the lack of experience and knowledge in this field, they are often missed or improperly treated. Most often they are caused by an indirect mechanism, during strength sports, typically using the bench press. In clinical terms, they are typically characterized by specific disorder of the anterior axillary fold and a hematoma and, after subsidence of the swelling, disfiguration with medial retraction of the muscle belly. The most beneficial imaging method to examine these injuries is MRI with an emphasis on a properly set protocol. According to the Cordasco classification, they are categorized as PM distensions, isolated and complete ruptures. Ruptures involve most frequently the musculotendinous junction and tendon insertion. Operative treatment is indicated in isolated complete ruptures of one portion and complete ruptures of both portions of the pectoralis major tendon, predominantly in young active patients with high functional demands. Surgery should be preferably performed without delay, within no more than 6 weeks, in order to ensure the best results. The most common operative technique is reinsertion of the muscle by means of implants or direct suture. In chronic ruptures, it is often necessary to perform a reconstruction with a tendon graft. The results are good, although worse as compared to an early treatment.

• Klíčová slova
• Bak criteria, Cordasco classification, cortical button, pectoralis major muscle, tendon injuries,
• MeSH
• lidé MeSH
• magnetická rezonanční tomografie škodlivé účinky   MeSH
• prsní svaly * zranění   chirurgie   MeSH
• ruptura etiologie   chirurgie   MeSH
• šlachy * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVE: To identify intracerebral sites activated after correct motor response during cognitive task and to assess associations of this activity with mental processes. METHODS: Intracerebral EEG was recorded from 205 sites of frontal, temporal and parietal lobes in 18 epileptic patients, who responded by button pressing together with mental counting to target stimuli in visual oddball task. RESULTS: Post-movement event-related potentials (ERPs) with mean latency 295 ± 184 ms after movement were found in all subjects in 64% of sites investigated. Generators were consistently observed in mesiotemporal structures, anterior midcingulate, prefrontal, and temporal cortices. Task-variant nonspecific and target specific post-movement ERPs were identified, displaying no significant differences in distribution among generating structures. Both after correct and incorrect performances the post-performance ERPs were observed in frontal and temporal cortices with latency sensitive to error commission in several frontal regions. CONCLUSION: Mesiotemporal structures and regions in anterior midcingulate, prefrontal and temporal cortices seem to represent integral parts of network activated after correct motor response in visual oddball task with mental counting. Our results imply equivalent involvement of these structures in task-variant nonspecific and target specific processes, and suggest existence of common nodes for correct and incorrect responses. SIGNIFICANCE: Our results contribute to better understanding of neural mechanisms underlying goal-directed behavior.

• Klíčová slova
• Correct performance, ERP, Error, Intracerebral EEG, Monitoring, Movement,
• MeSH
• dospělí MeSH
• elektroencefalografie metody   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mozek fyziologie   MeSH
• pohyb fyziologie   MeSH
• psychomotorický výkon fyziologie   MeSH
• světelná stimulace metody   MeSH
• zrakové evokované potenciály fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Traditionally, the pathophysiology of cervical dystonia has been regarded mainly in relation to neurochemical abnormities in the basal ganglia. Recently, however, substantial evidence has emerged for cerebellar involvement. While the absence of neurological "cerebellar signs" in most dystonia patients may be considered at least provoking, there are more subtle indications of cerebellar dysfunction in complex, demanding tasks. Specifically, given the role of the cerebellum in the neural representation of time, in the millisecond range, dysfunction to this structure is considered to be of greater importance than dysfunction of the basal ganglia. In the current study, we investigated the performance of cervical dystonia patients on a computer task known to engage the cerebellum, namely, the interception of a moving target with changing parameters (speed, acceleration, and angle) with a simple response (pushing a button). The cervical dystonia patients achieved significantly worse results than a sample of healthy controls. Our results suggest that the cervical dystonia patients are impaired at integrating incoming visual information with motor responses during the prediction of upcoming actions, an impairment we interpret as evidence of cerebellar dysfunction.

• MeSH
• bazální ganglia patofyziologie   MeSH
• dospělí MeSH
• dystonie vrozené   MeSH
• lidé středního věku MeSH
• lidé MeSH
• motorické korové centrum patofyziologie   MeSH
• mozeček patofyziologie   MeSH
• pohyb fyziologie   MeSH
• psychomotorický výkon fyziologie   MeSH
• reakční čas fyziologie   MeSH
• senioři MeSH
• tortikolis vrozené   patofyziologie   MeSH
• vnímání času fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVES: Supplementary motor area (SMA) was suggested to have a dominant role in the temporal control of behavior by many neuroimaging studies. The aim of this study was to support this hypothesis by influencing time estimates with theta burst transcranial magnetic stimulation (TMS) over the SMA. METHODS: Nineteen healthy volunteers with a mean age 25.9±3 (SD) years performed the time reproduction task (TRT) before and after 190 seconds of intermittent theta-burst TMS over SMA and the precuneus (total 600 pulses). The TRT consisted of an encoding phase (during which visual stimuli with durations of 5, 10 and 16.82 seconds were presented pseudorandomly) and a reproduction phase (during which interval durations were reproduced by pressing a button). Mean subjects' interval estimates as a measure of accuracy and standard deviation as a measure of variability pre-TMS and post-TMS were compared. RESULTS: Theta-burst TMS over both areas had no effect on the accuracy of duration estimates. An increased variability of interval reproduction was present after stimulation of the precuneus (p<0.01) with the biggest effect on the five second interval. Stimulation of SMA caused a decrease of variability in the ten second interval only (p<0.05). CONCLUSION: It is likely that increased variability of time estimates is a non-specific result of impaired attention and working memory after theta-burst TMS. Decreased variability after stimulation over the SMA could be explained in terms of enhanced activity of the physiological oscillator with a frequency close to 0.1 Hz.

• MeSH
• dospělí MeSH
• kognice fyziologie   MeSH
• krátkodobá paměť fyziologie   MeSH
• lidé MeSH
• mladý dospělý MeSH
• motorické korové centrum fyziologie   MeSH
• pozornost fyziologie   MeSH
• psychomotorický výkon fyziologie   MeSH
• světelná stimulace metody   MeSH
• theta rytmus EEG fyziologie   MeSH
• transkraniální magnetická stimulace metody   MeSH
• vnímání času fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

I describe a new irrigating iris retractor for cataract surgery in small pupils. The retractor, a modified irrigating handpiece has a smooth button-like iris hook in the front. The hook is inserted into the margin of a small pupil and retract the pupil peripherally to allow visualisation of cortical remnant in the equatorial area of the lens capsule. The capsule can then be safely cleaned using the aspirating handpiece in the surgeon's other hand.

• MeSH
• extrakce katarakty přístrojové vybavení   metody   MeSH
• iris chirurgie   MeSH
• léčebná irigace přístrojové vybavení   MeSH
• lidé MeSH
• pupila MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH

The aim of our study was to verify reported visual dysfunctions of patients with Alzheimer disease with the use of several variants of VEPs and visual ERPs and to learn whether these methods can be useful in diagnostics of AD. We tested 15 patients (6 women and 9 men, aged from 58 to 87) with mild to moderate Alzheimer disease (12-23 points of Mini Mental State Examination) and 15 age, gender and education level matched controls. The examination consisted of VEPs to pattern-reversal and motion-onset stimulation (to translational and radial movement) and of visual ERPs recorded during an odd-ball test. The subjects were instructed to signalize target stimuli by pressing of a button, which enabled to evaluate also the reaction time. While pattern-reversal VEPs were comparable in patients and controls, there were significantly smaller N2 peak amplitudes of motion-onset VEPs in patients with AD (in particular in radial moving stimuli outside the central 20 deg of the visual field), which suggests a dysfunction of the motion-processing (magnocellular) system or the dorsal cortical stream. ERPs, having significantly longer latencies in patients than in controls, distinguished well both groups. However, the individual AD diagnostics based on ERPs seems to be limited by rather high inter-individual variability of the ERP latencies. The ERPs might, however, be useful in disease progress and therapy effect estimation. Electrophysiological parameters did not correlate with neuropsychological ADAS cog test (Alzheimer Disease Assessment Scale--cognitive part).

• MeSH
• Alzheimerova nemoc patofyziologie   psychologie   MeSH
• evokované potenciály MeSH
• kognice * MeSH
• lidé středního věku MeSH
• lidé MeSH
• psychologické testy MeSH
• reakční čas MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• stupeň závažnosti nemoci MeSH
• světelná stimulace metody   MeSH
• vnímání pohybu * MeSH
• zrakové evokované potenciály * MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

OBJECTIVE: This study investigated the possible linkage of intracerebrally recorded P3-like waveforms to the processes induced by stimulus perception or motor response formation. METHODS: Event-related potentials were recorded from 560 cerebral sites in 17 patients suffering from intractable epilepsy during visual oddball task. Potentials evoked by the target stimuli were sorted according to button-pressing response times, and the P3 waveform was analyzed both in stimulus-locked and response-locked averages, which were separately averaged for fast and slow responses. RESULTS: P3-like waveforms were identified in 180 sites in 17 patients. Three different types of P3-like waveforms, diffusely distributed within the brain, were found: (1) time-locked to the stimulus (30 sites in 11 patients); (2) time-locked to the motor response (52 sites in 13 patients); and (3) with ambiguous time relationship to stimulus and motor response (98 sites in 16 patients). CONCLUSIONS: The intracerebral P3-like waveform could represent different processes involved in performing active oddball tasks. Therefore, our results support the hypothesis that the P3 waveform registered by surface electrodes could be a heterogeneous phenomenon. SIGNIFICANCE: These results provide evidence that the P3 waveform is not only related to stimulus processing, which differs from what has been generally claimed in the literature.

• MeSH
• analýza rozptylu MeSH
• časové faktory MeSH
• dospělí MeSH
• duševní procesy fyziologie   MeSH
• elektroencefalografie metody   MeSH
• epilepsie patofyziologie   MeSH
• funkční lateralita fyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mapování mozku MeSH
• mozková kůra anatomie a histologie   patofyziologie   MeSH
• pohybová aktivita fyziologie   MeSH
• psychomotorický výkon fyziologie   MeSH
• reakční čas fyziologie   MeSH
• světelná stimulace metody   MeSH
• zrakové evokované potenciály fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

The P3 wave of event-related potentials was recorded with intracranial electrodes in 24 epileptic patients during the pre-surgical evaluation of epilepsy surgery. Three different cognitive auditory paradigms were used: (1) odd-ball paradigm with no output required (PGI) where patients had simply to recognize target tones, (2) odd-ball with motor response (PGII), where patients had to press a button in response to target tones, and (3) odd-ball with both counting task and motor response (PGIII), where patients had to recognize target tones, press a button in response to them, and count their number. The occurrence of P3 potential, its latency and amplitude, and the dependence of P3 latency on the task complexity were calculated. Identifiable P3 potentials in all the three paradigms were recorded from locations in mesial cortex (18 locations mesial temporal, eight locations mesial frontal, two locations mesial parietal) and lateral sites (eight sites lateral temporal, five lateral frontal, and two lateral parietal). P3 latency values ranged from 257 to 320 ms in all explored cortical areas when PGI was used; they significantly increased or decreased during PGII and PGIII, depending on the task and structure explored. In the mesial temporal cortex, the changes of P3 latency between paradigms were minimal. In the mesial parietal cortex, there was significant P3 delay in both PGII and PGIII relative to PGI. In the mesial frontal cortex, there was a significant latency decrease in PGII, and practically identical mean latency in PGI and PGIII. In all lateral cortices (temporal, frontal and parietal), there was always a P3 latency increase in PGII and PGIII relative to PGI, the most significant results being observed in the parietal and frontal lateral areas. The results support the multi-generator theory of P3. Prolongation of the mean P3 latency in lateral frontal and parietal cortices when the paradigm involved the execution of a motor task might reflect specific gating in this area during active movements, while the absence of modification in the temporal lobe may reflect minimal involvement of this region in motor planning or processing. The prolongation of mean P3 latency in practically all lateral structures in PGIII suggests that most cortical areas were involved in the cognitive functions needed for this test. The finding of reduction and subsequent prolongation of P3 latency in the mesial frontal cortex might reflect the unique specialization of this area and its specific involvement in motor processing.

• MeSH
• čelní lalok fyziologie   MeSH
• dospělí MeSH
• elektroencefalografie * MeSH
• epilepsie patofyziologie   MeSH
• evokované potenciály fyziologie   MeSH
• funkční lateralita fyziologie   MeSH
• lidé MeSH
• mladiství MeSH
• neurochirurgické výkony MeSH
• pohybová aktivita fyziologie   MeSH
• psychomotorický výkon fyziologie   MeSH
• sluchové evokované potenciály fyziologie   MeSH
• spánkový lalok fyziologie   MeSH
• temenní lalok fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• práce podpořená grantem MeSH

OBJECTIVE: To assess the contribution of different anatomical brain sites to the genesis of P3 phenomena with respect to button pressing versus mental counting tasks. METHODS: Eight intractable epileptic patients undergoing depth electrode recordings prior to their surgery participated in the study. A total of 546 cerebral sites were recorded. A standard somatosensory oddball paradigm was used. The experiment was carried out in two sessions, differing in the requested responses to targets. The averaged responses in both tasks were compared. RESULTS: After targets, two kinds of P3-like potentials were observed within different cortical sites. Task-non-specific P3 potentials were seen for both types of responses to targets. The mean amplitude of these task-non-specific P3 potentials was significantly higher in the button pressing task. The intracerebral generators of this somatosensory P3 did not differ from the known generators of auditory and visual P3s. Task-specific P3-like potentials were found much less frequently. Button pressing unequivocally generated additional P3-like potentials in the premotor cortical sites. Mental counting repeatedly evoked additional P3-like waveforms in the left-side middle and inferior temporal gyri. CONCLUSIONS: In addition to multiple intracerebral P3 generators that reflect target detection processing, other task-specific P3-like potential generators can be found in the human brain. Their activity may affect the topography and precise parameters of scalp P3 potential.

• MeSH
• analýza rozptylu MeSH
• dospělí MeSH
• duševní procesy * MeSH
• elektrody MeSH
• elektroencefalografie MeSH
• epilepsie patofyziologie   MeSH
• funkční lateralita MeSH
• fyzikální stimulace MeSH
• kognitivní evokované potenciály P300 fyziologie   MeSH
• lidé MeSH
• mapování mozku * MeSH
• reakční čas MeSH
• somatosenzorické evokované potenciály * MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH