Biomedical subjects

Y Nakatsuchi

Publications and source records attributed to Y Nakatsuchi.

At least 19 recordsLinked to original sources

PubMed2006

Closed rupture of the flexor tendons of the little finger secondary to non-union of fractures of the hook of the hamate.

We report six patients with closed flexor tendon rupture affecting the little finger, occurring secondarily to non-union of the hook of the hamate bone. The ununited fragments were separated from the basal part of the hook by more than 1mm. The fragments were also rounded and showed marginal sclerosis. Non-union was located in the middle part of the hook in three patients, the tip in two, and the base in one. At operation, the fragments were removed in all patients. Five patients were treated by free tendon grafts using three palmaris and two plantaris grafts and one underwent tendon transfer. Postoperative total range of active motion of the little finger averaged 218 degrees (range 185-265 degrees ). All patients returned to their original employment. This series would suggest that flexor tendon rupture can occur after fracture of the hook of the hamate bone, even when the ununited fragment is small and/or rounded.

Adult↗

PubMed1999

Contact area of the trapeziometacarpal joint.

Eighteen cadaver hands were studied to determine the contact area of the trapeziometacarpal joint by using silicone rubber casts. Casting material was introduced into the trapeziometacarpal joint during several motions of the thumb and the contact location was observed. The ratios of the contact area to the total joint area were calculated. The contact locations in opposition were the radial, volar, and ulnar segments of the trapezium and the dorsal, radial, and volar segments of the metacarpal. On average, 53% of the trapezium was in contact with 53% of the metacarpal in opposition, while 28% of the trapezium was in contact with 28% of the metacarpal in palmar abduction and 25% of the trapezium was in contact with 25% of the metacarpal in radial abduction. The contact area was the largest in opposition. The trapeziometacarpal joint is stable in opposition and facilitates a strong pinch.

Aged↗

PubMed1999

Scaphoid nonunion and flexor pollicis longus tendon rupture.

Four patients presented with a rupture of the flexor pollicis longus tendon that was associated with a longstanding scaphoid nonunion. A radiocarpal arthrosis was present in 3 of the 4 patients and a dorsiflexed intercalated segment instability deformity was also seen in 3 of the 4 patients. Three patients underwent surgery consisting of an osteosynthesis with an iliac bone graft for the scaphoid nonunion and a palmaris longus tendon graft for the ruptured flexor pollicis longus tendon. An osseous union of the scaphoid and a functional active range of motion of the thumb interphalangeal joint (33 degrees on average) was attained in all 3 of the patients treated surgically. Preoperative radiologic examinations and intraoperative findings suggest that the volarly protruding distal scaphoid segment is the cause of the rupture.

Aged↗

PubMed1999

Granular cell tumour of the ulnar nerve.

Although granular cell tumours have been demonstrated to have a neural origin, they rarely arise in peripheral nerve trunks. We report a case of granular cell tumour of the ulnar nerve in a 51-year-old man. Though dissectable from the nerve, this intraneural tumour showed microscopic involvement of focal nerve fibres. This tumour tended to infiltrate the nerve in the same manner as a neurofibroma.

Granular Cell Tumor↗

PubMed1996

Alternation in the coronary blood flow velocity pattern in patients with no reflow and reperfused acute myocardial infarction.

BACKGROUND: Experimental and clinical evidence indicates that myocardial ischemia often damages the coronary microvasculature ("no-reflow" phenomenon). In this study, we examined the effect of this phenomenon on the coronary blood flow velocity pattern in patients with reperfused acute myocardial infarction. METHODS AND RESULTS: We measured coronary blood flow velocity after coronary angioplasty in 42 patients with acute myocardial infarction using a Doppler guidewire. Myocardial contrast echocardiography (MCE) was also performed before and after angioplasty. Thirty-one patients showed good contrast reperfusion (MCE reflow), whereas the other 11 showed no reflow (MCE no reflow). Peak velocity and duration of systolic coronary flow were significantly less in patients with MCE no reflow than in those with MCE reflow (8 +/- 4 versus 17 +/- 10 cm/s and 207 +/- 79 versus 289 +/- 55 ms, respectively; P < .01). Early systolic retrograde flow was frequently observed in patients with MCE no reflow, whereas it was observed in only 1 patient among those with MCE reflow (95% versus 3%; P < .001). Although peak diastolic flow velocity was similar between the two subsets, diastolic deceleration rate was significantly higher in patients with MCE no reflow than in those with MCE reflow (107 +/- 76 versus 56 +/- 31 cm/s2; P < .01). CONCLUSIONS: The coronary flow velocity pattern in patients with the no-reflow phenomenon was characterized by the appearance of systolic retrograde flow, diminished systolic antegrade flow, and rapid deceleration of diastolic flow. Thus, the Doppler guidewire allows us to assess the presence of microvascular dysfunction in AMI.

Aged↗

PubMed1996

Differential regional sympathetic responses to somatic stimulation in anesthetized dogs.

The present study was designed to determine whether regional differences exist in sympathetic responses to somatic nerve stimulation and whether the baroreceptor reflex modulates this somato-sympathetic reflex. The cardiac (CNA), renal (RNA), hepatic (HNA), splenic (SpNA) and adrenal (AdNA) sympathetic postganglionic nerve activities (SNA) were simultaneously recorded in anesthetized dogs with intact (n = 7) or bilaterally sectioned (n = 8) carotid sinus and vagus nerves. In the intact group, electrical stimulation of the left peroneal nerve at low intensity and low frequency (5 V, 5 Hz) produced a fall in mean arterial pressure (MAP) (-9.7 +/- 2.7 mmHg) and a decrease in each SNA with no regional differences RNA (79.2 +/- 8.5%), AdNA (82.7 +/- 5.4%), HNA (89.4 +/- 4.5%), CNA (87.5 +/- 3.5%), SpNA (84.2 +/- 3.2%). In contrast, stimulation at high intensity and high frequency (25 V, 50 Hz) produced a rise in MAP (+21.4 +/- 3.8 mmHg) and increases in SNA with quantitative predominance of RNA (178.6 +/- 13.6%) and AdNA (158.3 +/- 16.1%) over HNA (129.0 +/- 4.2%), CNA (117.7 +/- 7.6%), and SpNA (112.0 +/- 6.2%). Similar responses were observed when the left ulnar nerve was stimulated. The changes in SNA (delta SNA) at 10 s after the start of stimulation were plotted as a function of the changes in MAP (delta MAP) and the regression curves were determined. The best fit regression curve was a logistic sigmoid curve in the intact group and a linear one in the baroreceptor denervated group. Furthermore, delta RNA/delta MAP and delta AdNA/delta MAP during the somato-pressor response were significantly smaller in the intact group than in the denervated group. In conclusion, there are regional differences of sympathetic response during the somato pressor response but not during somato depressor response. The baroreceptor reflex may suppress the somato-sympathetic reflex of RNA and AdNA.

Animals↗

PubMed1996

Myocardial perfusion patterns related to thrombolysis in myocardial infarction perfusion grades after coronary angioplasty in patients with acute anterior wall myocardial infarction.

BACKGROUND: Epicardial coronary flow is occasionally reduced even after coronary intervention despite the absence of vessel obstruction in patients with acute myocardial infarction. Our aim was to clarify the cause and outcomes of radiocontrast slow filling in patients with reperfused acute anterior myocardial infarction by assessing microvascular damage with the use of myocardial contrast echocardiography (MCE) and functional outcomes. METHODS AND RESULTS: We carefully reviewed the cineangiograms of 86 patients who achieved coronary revascularization within 12 hours of the onset and underwent MCE before and soon after recanalization with the intracoronary injection of sonicated microbubbles. Antegrade coronary flow after recanalization was graded by two observers based on Thrombolysis in Myocardial Infarction (TIMI) trial flow grades. Left ventricular ejection fraction was measured on the day of infarction and 1 month later. TIMI grade 2 was observed in 18 patients (21%), and the other 68 patients manifested TIMI grade 3 after recanalization. All patients with TIMI 2 showed substantial MCE no reflow, whereas only 11 patients (16%) with TIMI 3 showed MCE no reflow. Functional improvement was worse in patients with TIMI 2 than in those with TIMI 3 (TIMI 2, 38 +/- 8% versus 40 +/- 8%, P = NS [acute versus late]; TIMI 3, 44 +/- 13% versus 55 +/- 13%, P < .001). Among patients with TIMI 3, significant functional improvement was observed only in patients with MCE reflow (MCE reflow, 46 +/- 13% versus 57 +/- 12%, P < .001; MCE no reflow, 35 +/- 11% versus 45 +/- 12%, P = NS). CONCLUSIONS: Despite no obstructive lesion of the vessel, TIMI 2 is caused by advanced microvascular damage and is a highly specific, although not sensitive, predictor of poor functional outcomes in patients with acute myocardial infarction. TIMI 3 does not necessarily indicate myocardial salvage, and detection of MCE no reflow in these patients is particularly useful for the prediction of functional outcome.

Adult↗

PubMed1996

Peroneal osteocutaneous flap raised on reconstructed popliteal artery for delayed union following open tibial fractures.

Two cases of delayed union following type IIIC open tibial fracture were treated by a pedicled peroneal osteocutaneous flap raised on reconstructed popliteal vessels. Dissection of the peroneal vessels from the already traumatized extremity was tedious, but this technique provided a reliable vascularized skin and bone graft that was indispensable for the fracture healing. Peroneal osteocutaneous flaps raised on the reconstructed popliteal artery have not been reported to date; they appear to be a good alternative to free osteocutaneous flaps for non-union of the proximal tibia.

Adult↗

PubMed1996

The vibrational mode of the tibia and assessment of bone union in experimental fracture healing using the impulse response method.

This study attempts to clarify the use of the impulse response method in the assessment of fracture healing. The vibrational mode as well as the effect of simulated callus consolidation on the vibrational parameters of excised human tibia were studied. Two separate vibrations were found, one vibrating strongly in the lateral direction and the other vibrating weakly in the antero-posterior direction. The ability to identify the primary vibrational mode in the lateral direction would make the impulse response method suitable for use in clinical practice. The callus consolidation process was simulated by the sequential consolidation of an adhesive material in an experimentally produced fracture gap. The change in hardness of the epoxy was found to correlate well with the change of resonant frequency of the bone. The resonant frequency demonstrated a steady increase during the initial phase of consolidation of the adhesive, up to about 40% of its final hardness. With the addition of various constructs for fracture fixation to the in vitro model such as a plate, Ender's pins, a Russell-Taylor intramedullary nail, or an Orthofix external fixator, the relationship between the consolidation of the 'callus' and the change in resonant frequency of the bone was not disturbed.

Bony Callus↗

PubMed1996

Long-term results of vein grafts interposed in arterial defects using the telescoping anastomotic technique and fibrin glue.

Fibrin glue has been applied in the anastomosis of vein grafts placed in rat femoral arteries using the telescoping technique at both ends of the graft. 34 out of 35 grafts which were patent 1 to 3 weeks post-operatively were kept for 3 months to assess the long-term patency, and the effect of the glue on the diameters of the graft and femoral artery. All 34 grafts were patent 3 months post-operatively. Excessive enlargement of the graft diameter was alleviated by the fibrin glue without affecting the diameter of the femoral artery. The diameter at the proximal anastomosis was 66% and that at the distal anastomosis was 87% of the diameter of the femoral artery.

Anastomosis, Surgical↗

PubMed1996

Assessment of fracture healing in the tibia using the impulse response method.

The resonant frequency of a long bone as measured using the impulse response method (IRM) can reflect the bending rigidity of the bone. A study was performed using IRM to quantitatively assess fracture healing in 67 tibial fractures. A temporary decrease in resonant frequency early in the treatment course was found in 55.6% of tibias, most frequently in the cases treated by external fixation (83.3%) and the AO plate (80%). The resonant frequency also decreased temporarily following the removal of the fixation devices in 76% of the tibias where they were removed. The resonant frequency of the fractured tibia at the final follow-up exceeded that of the contralateral side in 18% of tibias, approached within 20 Hz in 11.5%, and did not reach within 20 Hz in 70.5%. A questionnaire on the effectiveness of the IRM examination in the treatment of the tibia fractures was completed by the treating orthopaedic surgeons. The IRM examinations were found to be very useful in 58.2% of cases, useful in 31.3%, and useless in 10.4%. Thus, IRM examinations are most helpful when they are able to detect the change in bending rigidity early in the treatment of tibia fractures.

Acceleration↗

PubMed1995

Comparison of the telescoping anastomotic technique with the end-to-end technique utilizing vein grafts for venous defects: short- and long-term results.

The telescoping anastomotic technique was used for both anastomoses of vein grafts placed in the rat left epigastric vein in an effort to make the anastomosis easier and faster. Vein grafting in the right epigastric vein was completed using the conventional technique. The 20 rats with 20 left and 13 right vein grafts, which were patent at 3 weeks, were seen again 3 months postoperatively to compare the two techniques with regard to long-term stenosis and histological changes. Patency of the grafts 2 hr postoperatively was also compared between the two techniques in another 25 rats to eliminate the influence of recanalization on patency. All the vein grafts, which had been patent 3 weeks postoperatively, remained patent after 3 months and no statistically significant difference was found between the telescoping and conventional technique in the degree of stenosis. The vein grafts 2 hr postoperatively were all patent in both groups.

Anastomosis, Surgical↗

PubMed1995

Conservative treatment of thoracic outlet syndrome using an orthosis.

We describe a strapping device for elevation of the shoulder in patients with thoracic outlet syndrome (TOS). The device was used by 86 patients with TOS whose symptoms had been alleviated by passively raising the shoulder. Symptoms of TOS were classified as proximal, including pain in the shoulder girdle, and distal, in which there were neurological deficits related to the brachial plexus. The device was more effective in patients with distal symptoms: pain disappeared or improved in 67% of patients; numbness in 85%; sensory disturbance in 84%; and motor disturbance in 80%. However, proximal symptoms were relieved in only 65% of the patients. The ability to perform activities of daily living was rated as excellent in 33% of patients, good in 44%, fair in 12%, and poor in 9%. The shoulder orthosis described in this report can counterbalance downward traction on the brachial plexus and reduce the tension on it, thereby relieving symptoms of TOS.

Activities of Daily Living↗

PubMed1995

Telescoping and glue technique in vein grafts for arterial defects.

Fibrin glue was applied at the anastomotic site of the vein graft that was placed in rat femoral artery defects by the telescoping anastomotic technique at both proximal and distal anastomoses. All 35 vein grafts thus placed were patent, yielding a statistically higher patency rate than those placed in the same femoral artery by the same telescoping anastomotic technique but without fibrin glue. The telescoping anastomotic technique assisted by fibrin glue appears to give as reliable a patency rate as the conventional method even if it is used twice, both at the proximal and distal anastomoses, in autogenous vein grafting for arterial defects. Deformities of the inserted vessel should be minimized for patency by some means such as an application of fibrin glue so that the inserted vessel does not bulge under high arterial pressure.

Animals↗

PubMed1995

The influence of joints and soft tissue on the natural frequency of the human tibia using the impulse response method.

The influences of the joints adjacent to the human tibia, the surrounding soft tissue and the fibula on the vibrational parameters of the tibia (that is natural frequency, mode shape and damping ratio) are in need of clarification. Using five cadaveric human legs, the resonant frequency and damping ratio were measured with an accelerometer placed on the medial tibial condyle while the medial malleolus was impacted by an impulse hammer. The legs were subsequently dissected and the measurements were made in six conditions. The mode shape was obtained by use of modal analysis. Hammer impacts were given at 15 points along the three surfaces of the tibia, while an accelerometer was attached to the surface of the medial malleolus. Resonant frequencies ranged from 275 to 405 Hz in the intact specimens and successively increased with removal of the skin, muscles and foot, and then decreased with the removal of the femur and the fibula. Damping ratios successively decreased. The transitional pattern of natural frequencies was similar to that of the resonant frequencies. The mode shape represented the first bending mode and it corresponded to the condition of the tibia in which the proximal and distal ends of the bone were free.

Aged↗

PubMed1995

[Clinical application of digital TV tomosynthesis to disorders of the wrist and their post-operative evaluation].

The clinical utility of digital TV tomosynthesis was assessed in 13 patients with chronic disorders of the wrist and the first carpometacarpal joints, and a post-operative evaluation was carried out. The disorders included nonunion of the scaphoid in five patients, Kienböck's disease in four, subluxation of the distal radioulnar joint in two, and osteoarthrosis of the first carpometacarpal joint in two. The total time needed to obtain two sets of tomographs of a wrist by digital TV tomosynthesis was about 10 minutes, or approximately one third of the time required with conventional methods. The total radiation exposure in obtaining all tomographs of one direction with digital TV tomosynthesis was less than that in obtaining only one tomograph with conventional methods. Digital TV tomosynthetic images were judged superior to conventional tomographs by four orthopedic surgeons and four radiologists, because tomographic blur was reduced in part by a spatial frequency filter processing. Clinically, digital TV tomosynthesis was very helpful in evaluating nonunion of the scaphoid and Kienböck's disease, especially in their post-operative conditions with metallic fixative devices. Digital TV tomosynthesis was found to be a fast, feasible and inexpensive method with low radiation exposure for evaluating disorders of the wrist.

Adult↗

PubMed1994

Clinicopathological characterization of cardiac free wall rupture in patients with acute myocardial infarction: difference between early and late phase rupture.

Differences in morphological characteristics have been described in early phase and late phase post-infarction cardiac rupture. In this study, the clinicopathological characteristics of early and late phase rupture have been clarified by reviewing the clinical records of 1450 consecutive patients with acute myocardial infarction (AMI). Rupture of the left ventricular free wall (blow-out type) developed in 27 of the 1450 patients, and these patients were divided into two groups on the basis of the rupture time: early phase (< 72 h) and late phase (> 4 days). Only one patient had a history of prior infarction. Early phase rupture was characterized by an abrupt slit-like tear in the infarcted myocardium, a preference for anterior infarction sites, no prior myocardial infarction, and no difference in incidence in conventional and reperfusion therapy, while late phase rupture was characterized by the presence of infarct expansion, no preferential infarct site and a very low incidence in patients with successful reperfusion. Hence, early and late phase cardiac rupture differ in their pathogenesis, and thus the approach to the prevention and prediction of early and late phase cardiac rupture should be different.

Aged↗

PubMed1994

Anatomical and radiological evaluation of the triangular fibrocartilage complex of the wrist.

109 wrists from 69 cadavers (mean age 74 years) have been studied to clarify the pathology and morphology of the triangular fibrocartilage complex (TFCC) and to correlate pathological and radiological findings. Perforation of the TFCC was observed in 65% of the specimens and was considered to be secondary to a degenerative process, because it was often accompanied by degenerative changes in the ulnar carpal bones and perforation of the lunotriquetral ligament. To detect TFCC perforations on plain postero-anterior radiographs, it is important to evaluate ulnar plus variance and degenerative changes in the ulnar carpus. Existence of ulnar plus variance alone is more sensitive but less specific in detection of TFCC perforation than the existence of degenerative changes in the ulnar carpus.

Aged↗