Biomedical subjects
K Masada
Publications and source records attributed to K Masada.
Stretching of the brachial plexus in rabbits.
The brachial plexus of rabbits was stretched until mechanical failure. The level and site of rupture varied according to the direction of the stretching force. Upward and lateral traction of the forelimbs caused spinal nerve-root avulsions combined with nerve-trunk ruptures distal to the dorsal root ganglions. In such tractions the C5 nerves consistently exhibited postganglionic nerve-trunk rupture. The C6, C7, and C8 nerves had root avulsions. The T1 nerve was avulsed from the spinal cord in 7 cases out of 10; the other 3 cases had postganglionic nerve-trunk rupture. Downward traction of the forelimbs caused nerve avulsions from the scapulohumeral muscles innervated by the terminal branches of the brachial plexus and peripheral nerve ruptures in the course of the arm. The force producing trunk rupture of the C6 nerve was twice as great as that for root avulsion. The required stain was similar for nerve trunk rupture and root avulsion.
Nerve repairs for traumatic brachial plexus palsy with root avulsion.
Thirty-six patients with traumatic brachial plexus lesions and root avulsions were treated surgically between 1972 and 1986 and were followed for more than 24 months (average, 42.6 months). Neurotization of the musculocutaneous nerve with intercostal nerves or the spinal accessory nerve resulted in satisfactory elbow flexion in 21 of the 33 cases (64%). Combined nerve repairs (i.e., intercostal and spinal accessory neurotization of the terminal branch of the brachial plexus in combination with nerve grafts from the upper spinal nerves of the brachial plexus) created a useful function in at least one functional level of the upper limb for 11 of the 15 cases so treated. Nerve repairs resulted in stability of the shoulder and elbow function controllable with a sensible hand for patients with root avulsion injury of the brachial plexus.
Pathologic rupture of flexor tendons due to longstanding Kienböck's disease.
A 62-year-old man was seen for rupture of the flexor digitorum superficialis and profundus to the index finger. X-ray films showed longstanding Kienböck's disease with a completely fragmented lunate bone with fragments lying in front of the anterior lip of the radius. Tendon transfer restored active flexion to the index finger.
The effects of intra-arterially injected adriamycin on microvascular anastomosis.
Although free tissue transfer following limb-saving wide resection has become increasingly necessary in the treatment of sarcomas of the extremities, the side effects of adjuvant chemotherapy on the microvascular structure are not yet known. There may be significant effects, especially with intra-arterial administration. In order to study the time-dependent manifestations of possible effects, experimental microvascular anastomoses in the rat femoral artery were performed at various intervals, after intra-arterial injection of Adriamycin. This drug was used because of its popularity as an adjuvant chemotherapeutic agent. Vessels were examined at varying intervals for macroscopic changes affecting patency and for histologic changes. Anastomoses done at three weeks after Adriamycin injection resulted in the worst patency rate. Histologically, thrombotic occlusion was associated with widespread and profound disruption of the internal elastic lamina, thought to be thrombogenic trauma: the vessel was presumed to have been made fragile by preoperative Adriamycin treatment. Five weeks or longer after injection, this effect was reduced, according to patency rates and histologic findings. Endothelial damage was minimal and appeared insignificant.
Treatment of preaxial polydactyly of the foot.
Fourteen patients with preaxial polydactyly are classified into four types according to their morphologic configuration: type 1--ray duplication; type 2--completely duplicated phalanges; type 3--incompletely duplicated metatarsals; and type 4--incompletely duplicated phalanges. The surgical treatment and timing thereof appropriate for each group are discussed. Three cases of congenital hallux varus deformity are analyzed, focusing on the pathomechanism of this disorder. Based on our experience, two main factors are noticed in the etiology of congenital hallux varus deformity: inadequacy of the adductor hallucis and tightening of the fibrous band pulling the big toe into the varus.
Early microsurgical reconstruction in birth palsy.
Most patients with birth palsy can be expected to recover spontaneously. But in some patients the recovery is unsatisfactory and the functional results are disappointing. One possible way to improve the prognosis for such patients is early surgical nerve reconstruction. In six infants, exploration of the brachial plexus was carried out at about six months after delivery, when there were no signs of recovery in shoulder and elbow joint movements. Preoperative metrizamide myelography, computerized tomography with intrathecal metrizamide (CT myelography), and axon reflex test (histamine test) were followed by intraoperative electrophysiologic examinations of root sensory evoked potential (SEP), nerve action potential (NAP), and evoked muscle response (M-response). Microsurgical nerve repair was performed on the basis of intraoperative diagnosis. Metrizamide myelography showed 13% false-positive root avulsion. Reliability of the histamine test was 80%. The intraoperative electro-diagnosis is essential for understanding the actual condition of the brachial plexus lesion and obtaining better results from microsurgical reconstruction in birth palsy. The surgical results, with an average follow-up evaluation of two years and four months, have been encouraging enough to continue this diagnostic and therapeutic program, though its superiority to natural recovery has not yet been clarified.
Infantile digital fibromatosis after web construction in syndactyly.
A case of infantile digital fibromatosis with an unusual onset is reported. A Japanese girl, with a simple syndactyly of the right ring and little fingers, had an operation at the age of 2 1/2 years. Three months after the operation, multiple nodules appeared at the skin graft edge. The nodules were excised but soon recurred. When the patient was 8 years old, a large-scale excision of the tumors was performed. Intracytoplasmic inclusion bodies were shown by phosphotungstic acid-hematoxylin stain, and the case was diagnosed as infantile digital fibromatosis.
Congenital clasped thumb: a review of forty-three cases.
Over a 10-year period, 43 patients (75 hands) with congenital clasped thumb were seen in our institution. Three groups were identified: group I, 14 patients (24 hands) without contracture; group II, 14 patients (21 hands) with contractures of the palmar side; and group III, 15 patients (30 hands) with arthrogryposis multiplex congenita. Forty-two hands were treated with splinting alone and 16 hands with surgery. The remaining 17 hands were followed conservatively without splinting or surgery. The mean follow-up was 32 months. The results were evaluated by active abduction of the carpometacarpal joint and extension of metacarpophalangeal joint. All patients in group I showed good response to splinting, and the cause of the deformity appeared to be the predominance of the flexor muscles. In groups II and III, 10 patients (16 hands) who had severe deformity or no response to splinting were treated by release of the palmar soft tissues, skin grafts, and reconstruction of the extensors. Satisfactory results were obtained in 12 of 16 hands.
Multivariate analysis of stroke risk factors in Japanese rural districts.
Explore the source record for details and available documents.
[The effect of age on taste sensitivity].
Explore the source record for details and available documents.
Terminal limb congenital malformations: analysis of 523 cases.
A total of 523 Japanese patients with terminal limb congenital malformations were reviewed for the characteristic features, and especially for type correlation between hand and foot anomalies. There were 281 cases of hand involvement alone, 149 cases of foot involvement alone, and 93 cases of combined hand and foot involvement. Polydactyly was commonly preaxial in the hand and postaxial in the foot, in contrast to the well-known postaxial dominance in the hand among whites. Hand anomalies were likely to show the same Swanson type of anomaly as the foot, with the affected digital ray likely to be identical in both hand and foot.
Complications following metatarsal lengthening by callus distraction for brachymetatarsia.
We performed six metatarsal lengthenings in four patients for brachymetatarsia of the fourth toe by callus distraction from 1991 to 1995. Healing was achieved in all cases. The average amount of lengthening was 30% (range, 15-41%) of the original length. The average healing index was 82 days/cm (range, 66-113 days/cm). After the operation, range of movement of the metatarsophalangeal joint decreased in all cases (120 degrees before and 57 degrees after surgery). In two cases in which the lengthening exceeded 40% of the original length, stiffness of the joint (20 degrees and 0 degrees each) and joint deformity occurred. These two cases also had angulation of the metatarsal. Corrective osteotomy and release surgery was performed in one case. Angulation of the metatarsal was corrected, but the range of movement of the joint did not much recover after surgery. Another case was left untreated because the patient had no complaints. In metatarsal lengthening by callus distraction, the amount of lengthening should not exceed 40% of the original length.