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Biomedical subjects

S M Hou

Publications and source records attributed to S M Hou.

At least 91 records · Page 5Linked to original sources
PubMed1992

Bilateral severance of thumbs: report of two cases.

Management of hand injuries is a common practice but bilateral amputation of thumbs is very rare. We report on two cases of both thumbs amputated by a similar machine. In case 1, the man's left thumb was closed with a composite skin graft because the severance was through the middle of the nail. A wrap-around procedure was performed to reconstruct the right thumb which was infected after a primary V-Y advancement flap. The final results were acceptable. Replantation of detached thumbs, if possible, achieves the best functional recovery, which was well demonstrated in Case 2. Although the interphalangeal joints were arthrodesed, the patient was greatly satisfied with the results because of excellent appearance, adequate strength and nearly normal sensation. Prevention of bilateral thumb injuries is important. The paper-cutting machine on which these accidents occurred should be improved in order to prevent further similar catastrophes.

Adult↗
PubMed1992

Management of bony defects in open grade III fractures.

Early soft tissue reconstruction is recommended in treating open grade III fractures. Yet, there are still controversies regarding the way to handle bony defects when the soft tissue reconstruction is completed. This is a retrospective study to evaluate various methods of treating bony defects after soft tissue reconstruction in open fractures. From May 1985 to June 1988, we experienced 16 cases of open grade III fractures of the extremities with bony defects which received either local treatment with flap transfers (five cases) or free flap transfers (11 cases). The bony defects ranged from 3 cm to 10 cm in length. Cancellous bone grafting was performed in nine cases, and two of them received internal fixation at the same time. Seven cases received vascularized bone grafts (six fibulas and one iliac bone). Our results showed that bone grafting, with either a conventional cancellous bone graft or a vascularized bone graft, is useful in treating bony defects after soft tissue reconstruction. Internal fixation of the fractures after removing an extraskeletal fixator has the disadvantages of soft tissue breakdown and of possible infection. Early posterolateral bone grafting was beneficial if a cancellous bone graft was used on the tibia. Double free tissue transfers were quite useful, and we did not lose any free tissue transfers in our series. Vascularized bone grafts should be considered in cases where the osseous gap is greater than 6 cm, or where the recipient bed is bad.

Adolescent↗
PubMed1991

Absorption of lidocaine following topical application in microvascular procedures on rabbits.

Fifty rabbits were used to investigate the absorption of lidocaine following its topical application to blood vessels. The lidocaine level in the blood was determined by gas chromatography and the enzyme immunoassay. Animals were divided into five groups according to anatomic site (femoral vs iliac) and according to whether vessels were intact or anastomosed. In the last group (E), a water-tight sleeve was placed on the anastomosed femoral artery so that the lidocaine contacted only a small segment of the artery. In each group, 0.4 and 1 ml of 10% lidocaine were used. Our results revealed that absorption of lidocaine from topical usage was rapid. The absorption peak occurred within 5-15 min. The serum concentration of lidocaine was significantly higher in groups with intact vessels than in those with anastomosed ones. The peak level of lidocaine in the serum occurred sooner in the iliac area than in the femoral area. Absorption in group E was very low due to only a small segment of the artery being immersed with lidocaine. The main absorption site of lidocaine was not through the vessel but through the perivascular area. Toxicity may develop clinically if a high concentration of lidocaine is applied on a vessel during microsurgery.

Absorption↗
PubMed1991

Vascularized autogenous canine coccygeal bone transfer.

Based on cadaver studies in dogs, the 8th, 9th, or 10th canine coccygeal vertebra with overlying skin was designed for free vascularized bone transfer. In six dogs the coccygeal osteocutaneous flap was transferred to fill a defect of the tibia, anastomosing the median caudal artery and one of the two caudal veins to the tibial vessels. The overlying skin provided a reliable monitoring system for the transferred tissue. The behavior of the vascularized coccygeal vertebrae was then evaluated with radiographic and histologic examination and compared with control vertebrae transferred without reconnection of the blood vessels. The results revealed that the canine coccygeal bone graft is a reliable vascularized osteocutaneous flap, which can be applied either in clinical veterinary surgery or in orthopedic microsurgical research.

Anastomosis, Surgical↗
PubMed1990

Surgical treatment of tibial shaft fracture: experience of 207 cases.

From January 1984 to March 1988, 210 tibial shaft fractures in 207 patients treated by intramedullary nails, and by plate and screws and extraskeletal fixation were studied. There were 166 men and 41 women. Of the fractures, 95 (42.2%) of the 210 tibial shaft fractures were closed fractures and 115 (54.8%) were open fractures [Grade I: 44 (21.0%), Grade II: 39 (18.6%), and Grade III: 32 (15.2%)]. The incidence of associated injury was 44.3% and it was highest in the group with extraskeletal fixation (64.7%). Intramedullary nailing was performed in the majority of these fractures (127 out of 210) and yielded the best results in this series. Kuntscher's nailing resulted in nonunion in 3 cases (2.8%), superficial infections in 3 cases (2.8%) and deep infections in 4 cases (3.8%). Interlocking nailing resulted in nonunion in 1 case (4.8%), superficial infection in 1 case (4.8%) and deep infections in 3 cases (14.3%). Plate and screws fixation was performed primarily for metaphyseal fractures (71.4%) and resulted in nonunion in 4 cases (8.1%), superficial infection in 1 case (2.0%) and deep infection in 5 (10.2%). In the group treated with extraskeletal fixation, inasmuch as there were more cases of compromised soft tissue (open fracture, 97.1%), a higher incidence of associated major injuries (64.7%) and more cases of comminution of the bone (67.6%), the final results were less satisfactory. Nonunion was noted in 26.5% of the cases, superficial infection in 2.9% of the cases, and deep infection in 32.4% of the cases. From our study, we conclude that in appropriately selected patients, surgical fixation of tibial shaft fractures can produce a good functional recovery with an acceptable low rate of complications.

Adolescent↗
PubMed1987

An alternative technique of microvascular anastomosis.

The femoral arteries and veins of rats were severed and reanastomosed, using either the conventional interrupted suture technique or an alternative interrupted technique that allows the lumen to remain visible throughout the reanastomosis procedure. The alternative technique involves placing the sutures in the posterior wall of the vessel, eliminating the necessity of rotating the microsurgical clamp during the anastomosis. Clinically, this method may be advantageous in cases where the anastomosis is being performed in a deep wound in which there is no room to turn over the microclamp. Additionally, this technique allows the posterior wall of the vessel to be observed throughout the anastomosis procedure, reducing the possibility of accidental placement of sutures through the posterior wall and resulting nonpatency. There was no significant difference between the two techniques in terms of operating time, patency rate, aneurysm formation, arteriography, and histological findings.

Animals↗
PubMed1987

Use of the surgical glove in microsurgery.

The disposable surgical glove can serve as a model for toe-to-hand transfer, as a template for flap design, and as a ring tourniquet for the finger. The low cost, effectiveness, and easy handling of the glove warrant its role in reconstructive microsurgery.

Gloves, Surgical↗
PubMed1987

Relief of blood-induced arterial vasospasm by pharmacologic solutions.

A partially amputated rat hind limb model was used to evaluate the potency of 1 percent, 2 percent, and 20 percent Xylocaine, 0.3 percent papaverine, and normal saline in both the treatment and prevention of blood-induced arterial spasm. Direct application of blood to the femoral artery was shown to produce a 60 percent reduction in limb perfusion. The 0.3 percent papaverine and 20 percent Xylocaine solutions were statistically superior to normal saline and the lower Xylocaine concentrations in their ability to relieve the blood-induced vasospasm and prevent further spasm. Normal saline, 1 percent Xylocaine, and 2 percent Xylocaine showed no preventive effect against blood-induced spasm. These findings emphasize the importance of good hemostasis in microsurgery, and simplify the choice of an effective spasmolytic agent.

Amputation, Surgical↗
PubMed1987

Salvage of tourniquet-induced thumb necrosis by a modified wraparound procedure.

Rolled finger gloves were used as ring tourniquets on a case of amputation injury of bilateral thumbs. Necrosis of soft tissue of the right thumb occurred due to mistakenly prolonged use of the tourniquet. Later the patient successfully underwent a toe-to-thumb transfer (modified wraparound procedure). The precautions in using finger tourniquets are stressed.

Adult↗
PubMed1986

Blood-induced arterial segmental spasm.

Blood-induced arterial segmental spasm has been noticed clinically, and is thought to result from contact between a main feeding artery and extravasating blood from one of its side branches. This localized spasm can persist long enough to compromise the survival of a replantation or flap transfer. A partially amputated rat hind limb model was used to investigate this phenomenon. Bleeding from a side branch was shown to cause severe vasoconstriction and reduced limb perfusion only on direct contact with the main artery. Pretreatment with heparin and minimization of endothelial damage resulted in decreased vasospasm, but aspirin pretreatment had no effect on the degree of spasm and resulting reduced blood flow. This study demonstrates the clinical importance of careful ligation of side branches to reduce vasospasm that may compromise the survival of a replanted part or tissue flap.

Animals↗
PubMed1979

An investigation of the auditory frequency-following responses as compared to cochlear potentials.

Comparisons were made of cochlear microphonics (CM) and scalp recorded frequency-following responses (FFR) from chinchilla and human. The latency of the scalp/ear-lobe recorded FFR was found to be nearly zero with respect to CM. Further, auditory nerve action potential were noted to diminish rapidly after death whereas the CM component in FFR reduced gradually. The decay of the CM component of FFR measured at the scalp after death followed an identical time course to that of the CM at round window. These observation lead to the conclusion that FFR does not originate in the brain stem but is essentially cochlear potentials picked up by electrodes located at the scalp.

Action Potentials↗
PubMed1979

Ultrastructure of the turkey's basilar papilla and the damping elements in the scala media.

The ultrastructure of the turkey's inner ear was investigated by use of scanning and transmission electron microscopes. It was shown that hair cells of the basilar papilla are separated from each other by microvilli of the supporting cells. Organized compartments in the lower surface of the tectorial membrane of the turkey are arranged in polarized fashion as are the hair bundles. Kinocilia were not identified in the hair bundles examined in this study. Well-organized filamentous elements were observed in the cutucular plates. The continuation of these filamentous elements into the stereocilia indicates that the theory of adjustable resistor in generating cochlear potential may be closely associated with these elements. Membrane bound homogeneous material was found in the scala media between the tegmentum vasculosum and the tectorial membrane. The presence of this homogeneous damping material is believed to be essential in offsetting the sensitivity and enhancing the time resolution ability of the relatively short avian cochlea.

Animals↗
PubMed1978

Preliminary report on the effects of hyperoxia on cochlear potential in chinchilla.

Anesthestized chinchilla with round window electrodes were placed in a Plexiglas chamber. When they inhaled 100% oxygen at 1 atm, two types of neural effects were observed: 1. fast and reversible AP depression in response to brief exposure to 100% O2; and 2. a slowly developed chronic depression of AP and latency shift due to multiple hyperoxic exposures. The severity of the latter is a function of the dosage of the O2 inhaled, i.e., the concentration of oxygen and the length of time of exposure. For the type-1 effect, carbon dioxide deprivation is felt to be the immediate cause while the type-2 effect is mainly due to O2 toxicity developed at the intracellular level by high O2 concentration. The possible role of superoxide in the auditory O2 toxicity was discussed.

Action Potentials↗
PubMedDate not supplied

Early diagnosis of single segment vertebral osteomyelitis--MR pattern and its characteristics.

Nine cases of single segment vertebral osteomyelitis were included based on the single level of vertebral body involvement according to the MR findings. They were 3 cases with tuberculous infection and 6 cases with pyogenic infection. The vertebral body involvement was presented as abnormal signal changes (100%) and heterogenous enhancement (77.7%). They usually caused the cortical disruption in its anterior aspect (100%). It goes along the upward subligamentous spread (100%) most often, then the upper disc involvement (66.6%) and downward subligamentous spread (55.5%). The lower disc involvement is least common (11.1%). By using these criteria, the single segment vertebral osteomyelitis could be earlier diagnosed.

Adult↗