PubMed HealthSearch

Biomedical subjects

T M Tsai

Publications and source records attributed to T M Tsai.

At least 19 recordsLinked to original sources

Pre-operative factors and treatment outcome following carpal tunnel release.

The outcome of carpal tunnel release was evaluated retrospectively in 60 hands of 53 patients followed for six to 33 months (median ten months). Outcome was considered good in 27% (pain, weakness, and numbness were essentially resolved); fair in 42% (most of the symptoms improved); and poor in 32% (symptoms persisted or worsened). Patients whose pre-operative work activity was considered physically strenuous were associated with a slightly but significantly poorer outcome (60% good or fair) compared to those in light work or with no employment (89% good or fair). Proportionately fewer patients returned to their original work when they previously engaged in strenuous activity, ranging from 27% for those using air guns to 80% in light work. It appears that the highest chance of a poor outcome from carpal tunnel release occurs in patients who have either associated symptoms of thoracic outlet syndrome or physically strenuous work activities.

Adult

X-ray evaluation of radial shortening for Kienböck's disease.

The effect of inclination of the distal radius to subsequent lunate collapse is controversial. Therefore we evaluated the postoperative x-ray course of 10 patients with stage II, III, or IV Kienböck's disease who were treated only with radial shortening and followed up for an average of 25 months. The three patients who became worse as determined by x-ray evaluation had lunate fossa inclinations of less than 12 degrees after surgery. The four patients who improved had lunate fossa inclinations greater than 12 degrees. Appropriate radial shortening with adjunct wedge osteotomy to increase lunate fossa inclination may prevent further lunate collapse.

Adult

The osteocutaneous fibula flap: an anatomic study.

Recent studies related to the fibula flap have disagreed regarding the anatomy of the cutaneous branches of the peroneal artery. To clarify this issue, various dissections of 35 injected fresh cadaver legs were done. Identifiable skin branches were found in 23 of 25 dissections. Skin branches from the proximal third of the peroneal artery always travelled an intramuscular course. Skin branches from the distal two-thirds of the peroneal artery were usually affixed to the posterior crural septum. Legs with peroneal artery skin branches had from three to seven branches (average: 4.7); each branch contributed to the fibular periosteal blood supply. The most reliably found skin branch was located within 2 cm of the fibula midpoint. These findings reinforce the fact that a large skin island supplied by branches of the peroneal artery can be harvested with the fibula flap, and that the most reliable cutaneous vessels are found in the lower two-thirds of the leg, run posterior to the fibula in the posterior crural septum, and are always associated with muscular side branches.

Fibula

Functional results of vascularized versus nonvascularized nerve grafting.

Functional results of vascularized nerve grafts (VNG), end-to-end (E-E) repair, and nonvascularized nerve grafts (NNG) were compared using 75 rats. For all three groups, the sciatic function index (SFI) was measured for 12 weeks. For the vascularized nerve graft and nonvascularized nerve graft groups, it was measured every 4 weeks to week 36. The vascularized nerve graft and end-to-end repair groups showed significantly better recovery than the nonvascularized nerve graft group 4 weeks after surgery, and this pattern continued throughout the experiment. Results from the vascularized nerve graft and end-to-end repair groups did not differ significantly. Twelve weeks after surgery, morphologic and electrophysiologic assessments were used to compare the experimental and contralateral legs. The vascularized nerve graft group showed significantly better recovery than the nonvascularized nerve graft group on all measures except muscle weight and axon count, even though the grafts were completed in a normal bed.

Analysis of Variance

Vascularized joint transfers. Indications and results.

Vascularized joint transfer can be beneficial in restoring joint function and maintaining growth. It is sometimes indicated in patients with painful post-traumatic arthritis, post-traumatic joint instability, and post-traumatic deformity. The best indication for this procedure is in children whose joint injury is associated with damage to growth plates in any of the digits; however, the complications associated with this procedure should not be overlooked. Extensor lag is common. This complication may be prevented during the surgical procedure by using a step-cut osteotomy to preserve the insertion of the extensor tendon, resecting the volar plate of the finger, harvesting the transferred joint with enough length to keep the extensor tendon tight, and placing the transferred joint in a maximally extended position to counteract the flexible trend of the toe joints. We believe this procedure holds promise for the future. Further improvement in surgical technique and clarification of its indications will likely enhance overall results.

Arthrodesis

Free vascularized whole joint transfer in children.

Reconstruction of the traumatized finger joint with epiphyseal destruction has long been problematic. Since free vascularized whole joint transfer was introduced as a treatment for joint and epiphyseal destruction, this procedure has been selected as an alternative treatment because it may provide a growing epiphysis. We have reviewed our series of 19 joint transfers. Mean age at operation was 6.2 years (range 3 to 12). Average active range of motion was 31 degrees/61 degrees for the group with posttraumatic reconstruction (n = 12) and 21 degrees/43 degrees for the group with reconstruction of a congenital deformity (n = 7), with an overall average of 27 degrees/54 degrees. Average range of motion following transfer of an metatarsophalangeal (MTP) or metacarpophalangeal (MCP) joint to an MCP joint position was 39 degrees/75 degrees (n = 4); proximal interphalangeal (PIP) to PIP transfer was 22 degrees/39 degrees (n = 13); and PIP to MCP transfer was 38 degrees/51 degrees (n = 2). The proximal phalanges in MCP joints transferred to the MCP position grew an average of 7.0 mm, and the middle phalanges of joints transferred to the PIP position grew 4.3 mm. Almost normal growth was observed in all transferred joints except two that showed premature epiphyseal closure. Indications for this procedure and techniques to improve range of motion are described.

Arthroplasty

Revascularization of a finger with a thenar mini-free flap.

A devascularized index finger with a soft tissue defect on its palmar side was managed by using a small free flap raised at the level of the metacarpophalangeal joint of the thumb. The radial digital artery was included in the flap and used to revascularize the index finger, and a palmar vein was used to drain the flap. This resulted in minimal donor side morbidity.

Adult

Vascularized single toe joint transfer to the hand.

We report a retrospective review of our series of thirty-one single joints harvested from the toe in twenty-six patients and transferred to the metacarpophalangeal or proximal interphalangeal joint of the finger. Twenty-six transfers were done in traumatic cases and five in congenital. Follow-up averaged 22.6 months. Average range of motion was from 17.1 degrees to 44.3 degrees, with an arc of 27.2 degrees. The congenital group had an average motion ranging from 14.4 degrees to 27.2 degrees and an arc of 12.8 degrees. The traumatic group's motion was from 17.6 degrees to 47.6 degrees and an arc of 30.0 degrees. Complication rates were significant, with fifty percent of the patients experiencing one or more complications. Although vascularized joint transfer is a demanding procedure, it provides a reasonable alternative to arthrodesis and with further refinement in technique may become a reliable treatment option.

Adolescent

Sensory and motor fiber differentiation with Karnovsky staining.

We examined four acetylthiocholine methods based on Karnovsky's procedure--two fast-acting requiring 1 hour and two slow-acting requiring 24 hours. We compared these with our modification, which requires less than an hour and is simple to use. Rabbit sciatic nerves and spinal cords were used to compare methods. Our modification showed clearer differentiation than other fast-acting methods and staining identical to slow-acting methods. In blind examination of radial nerve specimens stained with our method, motor and sensory fascicles were correctly identified, showing sensitivity and specificity of 100%. In 12 clinical cases, our method produced staining in the proximal stump as long as 16 months after injury and in the distal stump as long as 5 days after injury. In 10 of 12 patients, this staining helped in aligning motor fascicles to motor fascicles and sensory fascicles to sensory fascicles.

Acetylthiocholine

Toe-to-thumb transfer: a new technique.

Our technique combines the advantages of two proven techniques of the wraparound flap and vascularized joint transfer while offering a more normal thumb, both functionally and cosmetically. Its advantages are as follows: 1. A more normal-looking thumb with good length 2. Preservation of motion through joint transfer 3. Maintenance of growth potential through transfer of vascularized epiphyses 4. Minimal donor-site morbidity

Adolescent

Per Primam thumb replantation for all patients with traumatic amputations.

Forty-two complete thumb replantations performed between 1980 and 1984 were reviewed. The mean follow-up time was 14 months. Replantation was attempted for all thumb amputations regardless of mechanism or severity of injury. Sixteen (38%) failed intraoperatively or postoperatively. Thumbs with narrow zones of injury showed a significantly higher survival rate than those with wide zones of injury. Eighty percent of those with poor arterial flow intraoperatively ultimately failed, despite pharmacologic treatment and multiple vein-graft anastomoses. Two thumbs with no vein repairs ultimately survived. Reexploration for loss of perfusion succeeded in 60% of cases. Total metacarpophalangeal and proximal interphalangeal active motion postoperatively averaged 68 degrees. Median static two-point discrimination returned to 11 mm. Avulsed thumbs survived in 46% of cases. Replantation should be attempted in all cases of thumb amputation, as success cannot be predicted by mechanism or severity of injury. Thumbs with poor intraoperative flow (20%) or no venous return (50%) can survive and should not be primarily amputated. Vein grafting is not mandatory if shortening allows anastomoses to be tension free. Prompt reexploration of acute vascular occlusions is worthwhile.

Adult

The repair of nail deformities with the nonvascularized nail bed graft: indications and results.

Twenty-four cases of nonvascularized nail bed grafting to correct nail deformities were reviewed. The highest success rate in improving the appearance of the deformed nail, 86%, was achieved when the split-thickness nail bed graft of sterile matrix was used to correct a nail deformity caused by a sterile matrix injury; the same procedure used to correct a nail deformity caused by a germinal matrix injury had a 0% success rate. Donor site morbidity occurred in 25% of split-thickness nail bed grafts and 100% of full-thickness nail bed grafts. The split-thickness nail bed graft of sterile matrix, if used in properly selected patients, will consistently improve the appearance of the deformed nail.

Adolescent

Improvement in motor function after brachial plexus surgery.

Motor functional recovery of 52 patients with brachial plexus surgery followed up for more than 2 years was evaluated. Fifty-eight surgical procedures were done, including autologous nerve grafting (38 cases), neurolysis (14 cases), and neurotization (6 cases). Overall results, evaluated according to the 0 to 5 formula of the Medical Research Council, were as follows: good, 58%; fair, 15%; and poor, 27%. Good results were evident in 58% of patients with nerve grafts and in 64% of those with neurolysis. In patients with neurotization, no good recovery and only one fair recovery were seen. Patients with open injuries showed good recovery, whereas the group with closed injury showed good recovery in only 48%. Patients with closed injuries caused by traffic accidents showed a worse recovery than those caused by other means. Patients with closed injuries and nerve grafting done within 3 months of injury or neurolysis within 6 months showed better recovery.

Adolescent

A technique for replantation of the finger tip.

The finger-tip replantation technique reported here has evolved over 15 years. Indications for surgery include both strong patient desire and specialized use of the finger tip. Palmar flaps are elevated as full-thickness skin grafts to avoid injury to palmar veins. Arteries and palmar digital veins are repaired using an open-vessel technique. Postoperative care varies from immediate discharge with follow-up to inpatient care using surgical leeches or continuous bleeding as a method of drainage should venous congestion develop. The survival rate of 26 finger tips replanted using this technique between 1981 and 1987 was 69%. Two-point discrimination returned in 75% of patients, and 25% had two-point discrimination of less than 5 mm. The distal interphalangeal joint retained an average range of motion of 56 degrees. Appearance was excellent, and patient satisfaction was high.

Fingers

Experimental replantation of canine forelimbs after 78.5 hours of anoxia.

To assess the effect of ischemia on osteocyte survival and longitudinal growth in bone, one forelimb of eight puppies and seven dogs was amputated, perfused with iced Collins solution, maintained at 4 degrees C for 72 hours (78.5 hours total anoxia), and replanted. Five puppies were kept for 1 year to assess bone growth. Undergoing bone labeling on days 1, 8, and 15, the other animals were sacrificed at 22 days to assess osteocyte survival. Osteocytes survived replantation in all dogs and one puppy; most osteocytes died in two puppies. In five long-term puppies, central epiphyseal growth was disturbed, but the peripheral portions maintained nearly normal growth, with almost normal bone length being achieved at 1 year.

Animals

Management of the traumatized joint of the finger.

Selection of the reconstructive technique for the traumatized joint requires a careful consideration of the condition of the injured and adjacent joints, the needs and desires of the patient, and an understanding of the advantages and disadvantages of the available options. The MP joint is the key to a useful arc of motion, providing 77 per cent of the total arc of flexion. Every effort should be made to preserve its maximum pain-free movement. PIP joint motion, although important in maintaining grip strength, can more readily be sacrificed to provide stability when MP joint motion is normal. Arthrodesis provides a pain-free stable joint with a sacrifice of motion. It may be indicated in young patients in whom heavy loading is likely; in joints with a fixed, painful deformity, instability, or loss of motor; and in the salvage of failed implant arthroplasty. Arthrodesis is generally contraindicated where physes are open. PIP joint arthrodesis is well tolerated in the index finger with minimal morbidity. Motion of MP joints and PIP joints of the long, ring, and small fingers, however, should be preserved using other techniques when possible. Resection arthroplasty may be useful in selected cases of post-traumatic arthroplasty where other treatment techniques are not available. Soft tissue interposition techniques are useful in specific cases. Eaton volar plate arthroplasty provides good results where 50 per cent of the articular surface is preserved. The technique, however, requires precision to avoid rotational malalignment. Perichondrial resurfacing provides a reasonable alternative in patients younger than 40 years of age who have a relatively well maintained joint contour, preferably involving a single joint surface. Prior infection is a relative contraindication. MP joints generally produce better results than PIP joints. Swanson interposition arthroplasty remains the most widely accepted implant technique, providing improved stability and earlier motion than simple resection arthroplasty. Reported arcs of motion range from a minimum of 29 degrees to a maximum of 85 degrees, with results generally better for MP than for PIP joints. Complications are common and include implant fracture, lateral instability of the PIP joint, and, occasionally, synovitis. Patient satisfaction, however, has been consistently reported as high. The use of Swanson arthroplasty in acute cases remains controversial, although several authors report favorable results. Silicone arthroplasty is contraindicated in joints with open physes. Allograft small joint reconstruction provides replacement bone and articular surface without donor site morbidity. Experience with the technique, however, has been limited. Increasing concern over the transmission of infectious diseases may make this option less desirable.(ABSTRACT TRUNCATED AT 400 WORDS)

Arthroplasty

Experimental comparison of vascularized and nonvascularized nerve grafting.

Previous studies have established the superiority of a vascularized nerve graft (VNG) over a nonvascularized nerve graft in a scarred recipient bed. This study compared the functional results of VNGs with nonvacularized nerve grafts (conventional nerve graft [CNG]) in a normal recipient bed. Forty rabbits were divided into two groups of 20 each. In one group a median nerve VNG was created in one forelimb. In the other group a CNG was created. Postoperative evaluation was performed at 10 and 24 weeks. Nerve conduction velocity, compound action potential area, axon diameter, and muscle weight did not demonstrate statistically significant differences. Axon counts and muscle strength did show a superior value for VNGs at 24 weeks.

Action Potentials

Survival and blood flow evaluation of canine venous flaps.

Using a canine model, we compared postoperative viability of saphenous venous flaps, cephalic venous flaps, and composite-tissue grafts without vascular connections. Of the saphenous flaps, 14 percent survived. Of the flaps based on the cephalic vein, 75 percent survived. Cephalic composite-tissue grafts were 13 percent successful. The presence of a more intricate venous plexus in a flap seems to increase its chances of success. Arterial injections of radioisotope-labeled microspheres were used to chart revascularization in cephalic flaps. These flaps demonstrated arterial blood flow by day 3, while the composite grafts showed no flow until day 7. Venous injections of microspheres distal to the flap were used to test vein-to-capillary blood flow. No significant entrapment of microspheres within the flaps occurred at any time, suggesting such flow to be inadequate.

Animals