A hinged, double-hook retractor design.
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Equipment Design↗
Biomedical subjects
S Karamürsel
Publications and source records attributed to S Karamürsel.
The 980-nm diode laser as a new stimulant for laser evoked potentials studies.
BACKGROUND AND OBJECTIVE: Lasers have been used as stimulators for creating pain response without stimulating mechanoreceptive fibers. Various laser systems are still under investigation on the quest for best laser system. Our objective was to test the feasibility of the 980-nm diode laser for LEP (laser evoked potentials) studies. STUDY DESIGN/MATERIALS AND METHODS: Laser evoked potentials created by using the 980-nm diode laser were recorded by using standard electroencephalogram (EEG) techniques. The collimated laser beam was 3 mm in diameter. Stimulus duration was set to 200 msec. The power of laser stimulus exposed to the dorsum of the right hand of 10 healthy volunteer subjects (5 women and 5 men) was varied between 0 and 10 watts to determine the pain threshold. EEG signals during the exposure of 1.5 times the threshold value were recorded from scalp electrodes placed on areas Fz, Cz, Pz, C3, and C4 according to the international 10--20 system. The stimulus presented during the EEG recording was described as a bearable pain sensation like a pinprick perception by the subjects. After 0.1--30 Hz analog low-pass filtering, 100-msec prestimulus, and 900-msec poststimulus EEG epochs were recorded at 256 Hz sampling rate and evaluated statistically. Thirty stimuli were presented by randomly varying the interstimulus duration between 5 and 9 seconds. RESULTS: Latency and amplitude values of LEPs were found in accordance with those reported in the literature. CONCLUSION: The 980-nm diode laser used is a suitable stimulator for LEP studies.
Adult↗
End-to-side microvascular anastomosis using an external metal ring.
Enthusiasm for developing safer and faster anastomotic techniques and complementary devices continues. We report on a new microvascular end-to-side anastomosis technique using a silver ring around the anastomotic circumference. The purpose of this study was to compare the effectiveness of this technique with conventional end-to-side vessel anastomosis. Forty Sprague-Dawley rats were divided into two groups. Twenty rats were used to assess the external ring method in end-to-side anastomosis between carotid arteries and anterior jugular veins and the remaining 20 formed the control group with conventional end-to-end anastomosis. The anastomosis time was 26.4 min for standard suture anastomosis and 18.4 min for the external ring technique (P< 0.01). Patency was 95% with standard technique and 100% using the external ring (P> 0.05). The external ring technique of end-to-side microvascular anastomosis is a safe and reliable method and may reduce the operation time. Its clinical applicability should be further evaluated.
Anastomosis, Surgical↗
Two new intramedullary implant designs for phalanx fixation in digital replantation: an experimental study.
Bone fixation in digital replantation must provide adequate rigidity, and must be applied in a fast and easy manner. Various fixation methods have been used so far with certain advantages and disadvantages. The authors report two new intramedullary proximal phalangeal implant designs to secure two amputated bone segments tightly. They compare their intramedullary implants with commonly applied K-wire fixation methods and plate fixation via biomechanical analysis in terms of bending rigidity and distraction strength. Their two-sided asymmetrical screw provided the highest rigidity and distraction strength, whereas the hook-trap system was nearly equal to cross-K-wire fixation. Intramedullary bone fixation may be a feasible method of bone fixation, and resorbable implant materials and different implant configurations deserve further investigation.
Amputation, Traumatic↗
End-to-side neurorrhaphies of the ulnar and median nerves at the wrist: report of two cases without sensory or motor improvement.
The authors present two unsuccessful clinical cases of end-to-side neurorrhaphy. In the first patient the distal median nerve was coapted in an end-to-side manner to the intact ulnar nerve. In the other patient four cables of sural nerve graft were used to bridge the ulnar nerve and the intact median nerve by two end-to-side coaptations. Neurorrhaphies were performed via epineural sutures through epineural windows. Both of the cases failed to demonstrate any signs of regeneration either clinically or as evidenced by electromyography, Semmes-Weinstein monofilament test, or 256-Hz vibration tests at 18 and 21 months' follow-up respectively.
Adult↗
Biconcave design of the silastic implant in temporomandibular joint disorder.
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Ankylosis↗
Lymphatic malformation causing intractable chylorrhagia.
Lymphatic malformation is a developmental error usually noticed at birth or in early childhood. Lesions of the upper leg and lower trunk are the most difficult to remove, because they are often the largest ones encountered and also because they tend to extend proximally into the retroperitoneal tissues. Chyle reflux, usually associated with lymphedema of the extremity, has not been reported to be caused by lymphatic malformation. We report a case of intrapelvic retroperitoneal lymphatic malformation with an extension of gluteal-thigh soft-tissue involvement causing intractable chylorrhagia. The tumor was subtotally excised, and the defect was closed by a distally based, peninsular latissimus dorsi myocutaneous flap. The flap served both as a filling material and as a "bridge" between the residual tumor, including abnormal lymphatics, and normal lymph flow.
Adolescent↗
A splint design for postoperative prominent ear retraction.
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Child↗
Repair of tips of microforceps.
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Microsurgery↗
Human auditory fast and slow omitted stimulus potentials and steady-state responses.
Two kinds of omitted stimulus potentials (OSP) are called "fast" and 'slow." Fast OSPs, recently found with visual stimuli, are here extended to auditory; they occur after omissions or after the end of trains of 1 to > 20 Hz clicks. Slow OSPs, long known, follow trains of 0.3 to 4 Hz. Each has its constant peak latency after the due-time of the first missing stimulus, as though the system is expecting something quite accurately on schedule. They differ in dynamics and slow OSPs require the subject to attend; fast OSPs do not. Steady-state responses (SSR) at a critical click rate of 6-7 Hz sometimes appear to alternate between two forms and OSPs may depend on which they follow. Fast OSPs can occur to the first, second and even the third omissions after the end of a train. Short conditioning periods suffice. Irregular interstimulus intervals do not reduce fast OSPs but attenuate slow OSPs.
Adult↗
Bartsocas-Papas syndrome with fusion of the lips and posterior fusion defects of the thoracic vertebrae.
Bartsocas-Papas syndrome is a rare popliteal pterygial syndrome with multiple anomalies including microcephaly, facial clefts, filiform bands, ankyloblepharon, syndactyly, and other ectodermal anomalies. Affected infants usually die perinatally. The authors present an 8-month-old female infant with manifestations of this syndrome and some additional traits including fusion of the lips, intraoral filiform bands, alopecia totalis, and posterior fusion failure of the vertebrae. The fused lips were opened by incising the fibrotic bands closing her mouth. Details of this patient and a brief review of the literature is presented.
Abnormalities, Multiple↗
A new epineural nerve repair technique: oblique nerve coaptation.
Despite the existence of various nerve coaptation techniques, functional results of nerve repair are still inadequate. Potential benefits of developing modified coaptation techniques cannot be disregarded. The authors report a new coaptation technique in which the nerves are cut in an oblique fashion to increase the coaptational surface. The sciatic nerves of male Wistar albino rats were cut at an angle of 30 and 45 deg (experimental groups), and 90 deg (control group). The nerves were repaired with nine 10-0 epineural stitches. Functional and histological studies were performed at week 12 on 7 rats from the 30-deg group, 15 rats from the 45-deg group, and 7 rats from the 90-deg group. Mean sciatic function index values of walking track analysis were the following: 30-deg group, -42.4+/-15.4; 45-deg group, -44.7+/-17.9; and 90-deg group, -52.9+/-13.9 (p>0.05). The mean values of myelinated axonal counts for the 30-deg, 45-deg, and 90-deg transection groups were 196.2+/-3.7, 196.1+/- 3.7, and 176.1+/- 5.6 respectively for proximal nerve segments and 180.1+/-6.8, 178.2+/-3.8, and 114.1+/-17.3 respectively for distal samples. Both the 30-deg and 45-deg coaptational groups had a significantly lower reduction of myelinated axonal counts at the regeneration zone in comparison with the 90-deg group (p<0.01). Mean myelinated axonal diameters in the proximal nerve segments were 8.2+/-2.6 microm, 8.4+/-3.1 microm, and 8.1+/-3.2 microm respectively, and were 7.1+/-3.6 microm, 6.9+/-3.4 microm, and 6.7+/-3.4 microm respectively in the distal nerve segments (p>0.05). The oblique nerve coaptation technique may enhance nerve regeneration by enabling a larger sprouting and contact area for nerve fibers, but additional investigation by more experienced centers is needed before relying on the preliminary results of this simple modification.
Animals↗
A new technique for microvascular anastomosis: external metallic circle.
Vessel anastomosis is the most critical step in free tissue transfers and replantation surgery. We report on a new microvascular anastomosis technique that uses a metallic circle around the anastomotic circumference. Sutures are first passed inside the circle and tied outside and over the circle so as to stretch open the anastomotic site. By retraction of vessel ends, the circle is totally exteriorized and thus there is no contact with blood. In 48 rats, the external circle method was compared with the conventional technique for constructing end-to-end anastomosis between carotid arteries (1 to 1.2 mm) and femoral veins (1 to 1.5 mm). The external circle method proved to be superior to the conventional end-to-end technique in speed of execution for both arterial and venous anastomoses. Patency rates at the third week were significantly higher in the venous group using the metallic circle (100 percent versus 70.8 percent, p < 0.05). This new method may be applicable in clinical microvascular surgery.
Anastomosis, Surgical↗
Primary hydatidosis of the thigh.
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Aged↗
Human Auditory Fast and Slow Omitted Stimulus Potentials and Steady-State Responses.
Two kinds of omitted stimulus potentials (OSP) are called "fast" and "slow." Fast OSPs, recently found with visual stimuli, are here extended to auditory; they occur after omissions or after the end of trains of 1 to >20 Hz clicks. Slow OSPs, long known, follow trains of 0.3 to 4 Hz. Each has its constant peak latency after the due-time of the first missing stimulus, as though the system is expecting something quite accurately on schedule. They differ in dynamics and slow OSPs require the subject to attend; fast OSPs do not. Steady-state responses (SSR) at a critical click rate of 6-7 Hz sometimes appear to alternate between two forms and OSPs may depend on which they follow. Fast OSPs can occur to the first, second and even the third omissions after the end of a train. Short conditioning periods suffice. Irregular interstimulus intervals do not reduce fast OSPs but attenuate slow OSPs.
Journal Article↗
Sensory processing in the pallium of a mormyrid fish.
To investigate the functional organization of higher brain levels in fish we test the hypothesis that the dorsal gray mantle of the telencephalon of a mormyrid fish has discrete receptive areas for several sensory modalities. Multiunit and compound field potentials evoked by auditory, visual, electrosensory, and water displacement stimuli in this weakly electric fish are recorded with multiple semimicroelectrodes placed in many tracks and depths in or near telencephalic area dorsalis pars medialis (Dm). Most responsive loci are unimodal; some respond to two or more modalities. Each modality dominates a circumscribed area, chiefly separate. Auditory and electrical responses cluster in the dorsal 500 micrometer of rostral and caudolateral Dm, respectively. Two auditory subdivisions underline specialization of this sense. Mechanoreception occupies a caudal area overlapping electroreception but centered 500 micrometer deeper. Visual responses scatter widely through ventral areas. Auditory, electrosensory, and mechanosensory responses are dominated by a negative wave within the first 50 msec, followed by 15-55 Hz oscillations and a slow positive wave with multiunit spikes lasting from 200 to 500 msec. Stimuli can induce shifts in coherence of certain frequency bands between neighboring loci. Every electric organ discharge command is followed within 3 msec by a large, mainly negative but generally biphasic, widespread corollary discharge. At certain loci large, slow ("deltaF") waves usually precede transient shifts in electric organ discharge rate. Sensory-evoked potentials in this fish pallium may be more segregated than in elasmobranchs and anurans and have some surprising similarities to those in mammals.
Acoustic Stimulation↗
Slow cortical potential shifts modulate P300 amplitude and topography in humans.
Effects of the spontaneous slow cortical potential (SCP) shifts of the electroencephalogram (EEG) on the P300 response were investigated on ten healthy volunteers. P300 responses were recorded using an auditory oddball paradigm, where target stimuli were presented regularly after every four standard stimuli. Single event-related potential (ERP) sweeps exhibiting negative or positive SCP shifts were averaged separately. The P300 amplitude was significantly larger during negative SCP shifts. Furthermore, the topographies of P200 and P300 waves obtained during negative and positive SCP shifts showed significant differences. The results indicate that the SCP shifts in single ERP sweeps, which are considered to be correlated with the arousal or basic activity level of the cortex, explain at least part of the inter-trial variability of P300 response.
Adult↗