Biomedical subjects

Y K Tu

Publications and source records attributed to Y K Tu.

At least 19 recordsLinked to original sources

PubMed2005

Inhibition of nitric oxide can ameliorate apoptosis and modulate matrix protein gene expression in bacteria infected chondrocytes in vitro.

Bacterial infection stimulates nitric oxide (NO) production in chondrocytes. However, the role of NO in chondrocyte apoptosis after infection remains unclear. The purpose of the study was to test if inhibition of NO could ameliorate apoptosis and modulate matrix protein gene expression in bacteria-infected chondrocytes. It was shown that pre-treating chondrocytes with L-NAME (1 mM) significantly decreased the release of NO (from 72 to 14 microM) and the extent of apoptosis (from 52.9% to 18.9%). Pre-treatment with L-NAME also counteracted the bacteria-induced downregulation of Type II collagen (from 26% to 79%) and aggrecan (from 63% to 105%) mRNA levels. Inhibition of NO after the induction of infection could not decrease the extent of apoptosis and modulate matrix protein gene expression. The results of this study support the hypothesis that NO has an important role in bacteria-induced chondrocyte apoptosis. Pre-treatment but not post-treatment could ameliorate the extent of apoptosis and reestablish the cartilage matrix protein gene expression. This study suggests that in addition to NO, other mechanisms may be responsible for the sustained destruction of articular cartilage in the post-infectious arthropathy.

Apoptosis↗

PubMed2003

Endovascular treatment of brain-stem arteriovenous malformations: safety and efficacy.

Our purpose was to evaluate the safety and efficacy of endovascular treatment of brain-stem arteriovenous malformations (AVMs), reviewing six cases managed in the last 5 years. There were four patients who presented with bleeding, one with a progressive neurological deficit and one with obstructive hydrocephalus. Of the six patients, one showed 100%, one 90%, two 75% and two about 50% angiographic obliteration of the AVM after embolisation; the volume decreased about 75% on average. Five patients had a good outcome and one an acceptable outcome, with a mild postprocedure neurological deficit; none had further bleeding during midterm follow-up. Endovascular management of a brain-stem AVM may be an alternative to treatment such as radiosurgery and microsurgery in selected cases. It may be not as risky as previously thought. Embolisation can reduce the size of the AVM and possibly make it more treatable by radiosurgery and decrease the possibility of radiation injury.

Adolescent↗

PubMed2001

Long-term clinical outcome of spontaneous carotid cavernous sinus fistulae supplied by dural branches of the internal carotid artery.

We report the long-term clinical outcome of spontaneous carotid cavernous sinus fistulae (CCF) originally supplied by branches arising from the internal carotid artery (Barrow's type B), or type-D lesion that became type B after particulate embolization. A total of 55 patients was included in this study. Their angiography revealed that cortical drainage was absent, and that the arteries supplying the fistulae originated in the dural branches of the internal carotid artery. Thirty-two patients had type-D lesions, which became type-B lesions after obliteration of the external carotid supply by endovascular treatment. The other 23 patients had type-B lesions documented by angiography, and had no embolization. The follow-up period ranged from 8 to 144.5 months. Clinical cure was achieved in 39 patients (70.9%), improvement in eight patients (14.5%), the lesion remained stable in four patients (7.3%), and was aggravated in four patients (7.3%). The number of drainage veins is the only radiographic factor that could predict the outcome. Those patients with single draining veins had a better chance of complete remission. The outcome between the group with original type D lesions after embolization and the group with original type B revealed no statistically significant difference. The time-course to complete cure was significantly shorter in the group with embolization of the external carotid supply. In the four patients whose symptoms were aggravated, embolization was performed, and the result was excellent. The clinical outcome of type-B CCF, or type D converted to type B, is good. Previous external carotid artery embolization can significantly shorten the time to complete cure. Aggressive treatment should be reserved for those who have aggravated symptoms.

Adult↗

PubMed2001

New application of heparin-bonded extracorporeal membrane oxygenation in difficult neurosurgery.

We wished to evaluate the safety and the advantages of using heparin-bonded extracorporeal membrane oxygenation (ECMO) to replace conventional cardiopulmonary bypass (CPB) in deep hypothermic circulation for complex cerebral aneurysm surgery.Heparin-bonded ECMO without the bridging tube and the cardiotomy reservoir was set up through the femoral vessels. Limited heparin was infused. In deep hypothermia, the ECMO blood flow was temporarily decreased as low as the neurosurgeons' request. It was applied to 4 patients with difficult intracranial aneurysms who were selected for the procedure. Clipping, wrapping, or vascular bypass was implemented to manage the aneurysms under deep hypothermia. The total heparin dosage used in the whole procedure was 9,875 +/- 1,625 U, and the mean ECMO time was 270 +/- 105 min. The blood consumption was packed red blood cell 3.0 +/- 0.5 U and fresh frozen plasma 3.8 +/- 2.3 U. Compared with our previous experiences using conventional CPB, ECMO did need less heparin and blood transfusions. Clipping was applied in 2 patients, wrapping in 1, and venous graft interposition was performed in 1. Mortality occurred in 1 patient (25%) due to brain herniation. This preliminary study suggested that the heparin-bonded ECMO without reservoir in deep hypothermia could be safe in cerebral aneurysm surgery under a low flow circuit.

Adult↗

PubMed2001

Reconstruction of posttraumatic long bone defect with free vascularized bone graft: good outcome in 48 patients with 6 years' follow-up.

We analyzed our clinical results in 48 patients (40 men) treated during 1990-1993 with free vascularized bone-graft reconstruction for bone defects, the follow-up being an average 6 (5-8) years. The bone defects were located in the femur (10), tibia (32), humerus (2), and forearm (4). We performed 41 fibula transfers, 4 iliac transfers, and 3 rib transfers in these patients. 3 patients required early revision surgery due to venous thrombosis. The average time needed for radiographic bone union was 4.2 months. Bone transfers to the lower extremity showed significantly more hypertrophy than those in the upper extremity. The functional outcome was good in 43 patients.

Adolescent↗

PubMed2001

Surgical treatment of spinal arteriovenous malformations: vascular anatomy and surgical outcome.

BACKGROUND AND PURPOSE: Spinal arteriovenous malformations (AVMs) are rare but debilitating lesions of the central nervous system. This study evaluated the outcome in patients with spinal AVMs treated surgically, and the relationship between outcome and the vascular anatomy of the lesions. METHODS: These AVMs were classified into four types: dural AVM (type I), glomus AVM (type II), juvenile AVM (type III), and intradural direct arteriovenous fistula (type IV). Either interruption of the feeding vessels or excision of the AVMs was performed in all patients. RESULTS: Intradural AVMs manifested as subarachnoid or intramedullary hemorrhages, whereas dural AVM manifested as epidural hemorrhage in two patients, and as an episode of subarachnoid hemorrhage in one patient. The nidus in five of the six dural AVMs was below the mid-thoracic level. In six of the seven patients with intradural AVMs, the nidus was located in the cervical region. The prognosis of patients with dural AVMs was generally good, but in patients with intradural AVMs, motor recovery was worse and resection was more difficult. CONCLUSIONS: Correct diagnosis and classification of spinal AVMs are the key prerequisites for successful treatment. The surgical outcome is closely related to the vascular anatomy of the lesion. For dural AVMs, only surgical interruption of the arteriovenous shunting at the dural sleeve of the nerve is required and good surgical results are often obtained. Intradural direct arteriovenous fistula responded well to surgery, whereas combined endovascular and microsurgical techniques can minimize the chance of rebleeding in intramedullary AVMs.

Adolescent↗

PubMed2001

Arthroscopy in avulsion fracture of posterior cruciate ligament.

BACKGROUND: Surgical reduction of PCL avulsion fracture was performed from posterior approach and arthroscopic treatment was not routinely performed. However, associated intraarticular lesions of meniscus, cartilage, of any other pathologies were very common in PCL injuries. If the treatments of associated intraarticular lesions would improve the results was not known. Under this prospective study, we want to know if arthroscope is valuable in PCL avulsion fractures. METHODS: From January 1995 to December 1997, there were 29 cases of PCL avulsion fractures. They were grouped according to chart numbers. Group I was even number group and group II was odd number group. Arthroscopic examination was performed in even number group, but not in odd number group. Group I had 13 cases and group II had 16 cases. All the PCL avulsion fractures were repaired from posterior approach and fixed with cancellous screws. RESULTS: The range of motion, arthrometric data, and Lysholm score were similar in both group after more than 2 years of follow-up. The residual pain was less in arthroscopic group. Arthroscopic examination showed hemarthrosis in all cases of group I; meniscal lesion in 7 cases (54%), osteochondral or chondral lesions in 3 cases (23%), hard medial plica in 3 cases (23%), patellofemoral lesion in 1 case (7.7%), ACL tear in 1 case (7.7%), popliteal lesion in 2 cases (15.4%), lateral opening greater than 1 cm in 5 cases (38.5%). Though the functional results were similar in both groups, the arthroscopic findings in PCL avulsion fracture were negative in only 2 cases. CONCLUSION: Arthroscopic examination in PCL avulsion fracture can provide valuable information.

Adolescent↗

PubMed2000

Transarterial embolisation of complex cavernous sinus dural arteriovenous fistulae with low-concentration cyanoacrylate.

We report the effectiveness of low-concentration n-butyl-2-cyanoacrylate (NBCA)-Lipiodol-tungsten mixture (10-15 %) in the management of patients with aggressive or recurrent complex cavernous dural arteriovenous fistulae (CSDAVF). We treated five patients with complex CSDAVF with a low concentration of an NBCA-Lipiodol-tungsten mixture after catheterisation of the feeding arteries arising from the external carotid artery. Three had a recurrent CSDAVF after transarterial particulate embolisation. Three refused transvenous treatment or could not be treated in this way; two patients had also feeding dural branches of the internal carotid artery. All patients had complete resolution of symptoms and signs within a month of the procedure. No definite neurological complication was found during follow-up ranging from 12 to 36 months. Transarterial embolisation with low-concentration cyanoacrylate appears to be an effective alternative management of aggressive or recurrent CSDAVF.

Arteriovenous Fistula↗

PubMed2000

Experimental carpal reverse-flow pedicle vascularized bone grafts. Part I: the anatomical basis of vascularized pedicle bone grafts based on the canine distal radius and ulna.

We investigated the detailed extraosseous and intraosseous vascular anatomy of the distal radius and ulna in 55 pairs of canine forelimbs. Ten specimens were used for compartment identification. One hundred specimens were investigated after intra-arterial injection with red latex or Batson's compound. The extraosseous vascular network, including the nutrient artery location, was studied by delicate dissection and soft tissue digestion. Two superficial and 4 deep arteries were found on the dorsal aspect, with constant relationships to the retinaculum. On the palmar aspect, bony nutrient vessels rose from the branches of the radial artery (descriptive anatomy). The vascular supply of the canine distal forelimb was very consistent and enabled the design of 5 vascularized pedicle bone grafts similar to those described in humans (applied anatomy). These reverse-flow pedicle grafts may be placed in the carpus, allowing the canine forelimb to serve as an experimental model for the study of vascularized carpal bone grafting. (J Hand Surg 2000; 25A:34-45.

Animals↗

PubMed2000

Experimental carpal reverse-flow pedicle vascularized bone grafts. Part II: bone blood flow measurement by radioactive-labeled microspheres in a canine model.

Reverse-flow pedicle vascularized bone grafts (VBGs) from the radius, commonly used for carpal nonunion and avascular necrosis, provide superior clinical results. In this experimental study bone blood flow in canine distal radius VBGs was measured to determine the status of the bone circulation immediately after elevation (group 1) and 2 weeks later (group 2). Immediate VBG flow (group 1) was substantial, but significantly less than the contralateral undisturbed distal radius (8.42 mL/min/100 g and 16.53 mL/min/100 g, respectively). At 2 weeks after surgery (group 2) VBG flow was compared with nonvascularized control grafts. Vascularized bone graft flow was significantly higher than group 1 (mean, 33.72 mL/min/100 g). Minimal flow was seen in the conventional graft control (0.62 mL/min/100 g). This study demonstrates that reverse-flow pedicle radius VBG maintain enhanced bone circulation long-term. Given the similarity of human and canine distal radius vascular anatomy, these data support the clinical use of reverse-flow VBG for carpal pathology. (J Hand Surg 2000; 25A:46-54.

Animals↗

PubMed2000

Experience in surgical management of tumours involving the cavernous sinus.

Potential injury to the neurovascular structures within the cavernous sinus often prohibits aggressive removal of tumours involving it, however, fully understanding the anatomy and selecting an appropriate surgical approach can often resolve this problem with acceptable morbidity. Moreover, a tumour may originate from different anatomical structures of the cavernous sinus which will influence the difficulty and outcome of the surgery. In general, tumours in this region can be classified as intradural, intracavernous and invasive types. The strategy of surgical treatment varies among these different anatomical types. Therefore, preoperative evaluation of tumours in the cavernous sinus is critical for the selection of an appropriate microsurgical approach. During the past 5 years, 12 tumours involving the cavernous sinus have been operated upon which included four neuromas, three meningiomas, three cavernous haemangiomas, one plasmacytoma and one chondroma. Nine of these twelve tumours were totally resected after one or two operations. There was no surgical mortality and the most common morbidity was transient cranial nerve palsy. At 2 months after surgery there was no additional postoperative cranial nerve deficit in all the patients; however, one patient developed a postoperative middle cerebral artery infarct due to accidental injury to the internal carotid artery during surgery. The respectability of the tumour mostly depends on its consistency and the involvement of the adjacent anatomy. The pathoanatomical features of the tumours and the clinicoradiological findings, as well as the selection of the microsurgical approach, are discussed.

Adolescent↗

PubMed2000

Complications of liner locking system in Micro-structured Omnifit acetabular components: a radiographic evaluation of 887 hips followed for 5-10 years.

We evaluated 887 hips in 672 patients with uncemented MicroStructured Omnifit acetabular components for liner locking complications. We found 2 types of radiographic signs of liner locking system complications in 7 hips, developing between 2 and 4 years postoperatively. The incidence of liner locking system complications was 0.8% using this modular acetabular component. We recommend that a patient who has received a total hip arthroplasty including a MicroStructured Omnifit acetabular component should be monitored frequently for radiographic signs of liner locking system complications, especially with a polyethylene thickness of less than 8 mm.

Adult↗

PubMed2000

Vascularized island pedicle iliac bone grafting for avascular necrosis of the femoral head.

BACKGROUND: Nontraumatic avascular necrosis of the femoral head is a common disorder causing disability of the hip joint. The methods for optimally treating this disease in active young patients are still controversial. In this study we investigated the surgical outcome of vascularized pedicle iliac bone grafting for treating nontraumatic avascular necrosis of the femoral head. METHODS: Between 1994 and 1999, we treated 100 cases of avascular necrosis of the femoral head with vascularized pedicle iliac bone grafting. Thirty-nine hips in 33 patients were followed-up longer than 24 months. These patients included 30 men and 3 women, with an average age of 40 years. Steinberg's classification and Ohzono's types were used to categorize the diseased hips. The clinical results were evaluated using Charnley's modification of Merle d'Aubigne and Postel's numeric classification. RESULTS: Of the 33 patients, 82% were satisfied with their decision to have vascularized pedicle iliac bone grafting for avascular necrosis of the femoral head. No serious complications arose during this study. The average operation time for vascularized pedicle iliac bone grafting was 3.5 hours for one team. The rate of conversion to replacement arthroplasty was 10.3% (4 of 39 patients). CONCLUSION: Vascularized pedicle iliac bone grafting is a useful alternative treatment option for patients with avascular necrosis of the femoral head.

Adult↗

PubMed2000

Tibial plateau fracture with compartment syndrome: a complication of higher incidence in Taiwan.

BACKGROUND: Compartment syndrome after tibial plateau fracture has been described, solely as case reports in previously published articles, as a relatively rare complication. METHODS: A retrospective review of 106 patients with 107 tibial plateau fractures was undertaken from January 1996 to June 1997 at a level I trauma center, and the incidence of compartment syndrome was 10.3%. The diagnosis was based on characteristic clinical symptoms and signs of acute compartment syndrome and/or by measurement of intracompartment pressures. The treatment included fasciotomy of the 4 compartments. RESULTS: There was a high correlation between the incidence of compartment syndrome and the fracture pattern as well as the mechanism of trauma. Higher-energy traumas (Schatzker's type IV, V, and VI) were associated with a higher incidence of compartment syndrome (30.4% in type VI). CONCLUSION: The incidence of compartment syndrome after tibial plateau fracture is more common than what has been reported in the literature, especially after high-energy trauma.

Adolescent↗

PubMed1999

Early polyethylene wear and osteolysis in cementless total hip arthroplasty: the influence of femoral head size and polyethylene thickness.

We examined initial polyethylene thickness, early polyethylene liner wear, and osteolysis in 350 primary, cementless total hip arthroplasties (THAs). All of the prostheses were of identical design and used Omnifit components. In the 32-mm head group, the mean liner wear correlated significantly with polyethylene thickness (P<.001) and increased rapidly with initial thinner polyethylene following a logarithmic model, although this increase was not statistically significant (r = -.633). Inadequate polyethylene thickness in the 32-mm head group was implicated as the major cause of higher liner wear. A minimal polyethylene thickness of 7 mm is recommended in cementless metal-backed THAs. The use of a large head combined with poor prosthetic design appeared to be responsible for the unacceptably high incidence of femoral osteolysis.

Acetabulum↗

PubMed1999

Knee dislocation: treatment of high-velocity knee dislocation.

BACKGROUND: We report the outcomes of patients treated with a new arthroscopic treatment modality for knee dislocation after high-velocity trauma. METHODS: Twenty-three patients (12 men, 11 women; 25 knees) with traumatic knee dislocation were treated with this technique. Under arthroscopy with gravity inflow irrigation, the ruptured posterior cruciate ligament was reconstructed with a patellar bone-tendon-bone graft, and the anterior cruciate ligament was debrided subacutely. The collateral ligament, meniscus, and capsules were repaired through additional incisions. RESULTS: The average interval between injury and surgery was 11.1+/-5 days (range, 5 to 25 days). After a mean follow-up period of 27.2+/-7.86 months, the mean extension was 1+/-2 degrees and the average flexion was 129.6+/-4.91 degrees. The mean Lysholm score was 84. There were no major complications. CONCLUSION: Arthroscopic posterior cruciate ligament reconstruction seems to be an effective treatment for traumatic knee dislocation.

Adolescent↗

PubMed1999

Reconstruction of ankle and heel defects by a modified wide-base reverse sural flap.

BACKGROUND: Flap reconstruction around the ankle and heel is a technically demanding procedure. Some patients have contraindications for microsurgery, however, limiting the options for local tissue transfer. In this study, we describe our experience with a new flap technique for ankle and heel coverage. METHODS: We designed a modified wide-base reverse sural flap and applied it to 20 patients with lower leg trauma from 1994 to 1997. All patients sustained Gustilo type IIIb,c open fractures with soft-tissue defects around the ankle and heel. Six cases had chronic osteomyelitis. Most of our patients had contraindications for microsurgery such as old age, poor medical condition, or heavy smoker status. The average age was 69.5 years old, and the average follow-up time was 18.5 months. RESULTS: All 20 patients underwent successful modified reverse sural flap reconstruction. There were no deep infections, no soft-tissue necrosis, or pressure ulcers. The nonunion rate was 5%. The average time for flap elevation and rotation was 29.3 minutes. No blood transfusion was required. An unsightly scar was the major complaint (60%) from our patients. Seventeen cases (85%) achieved good functional outcomes. CONCLUSION: This report demonstrates that our design of this modified wide-base reverse sural flap is suitable for flap reconstruction around the ankle and heel; especially for patients who have difficulty in receiving microsurgery. The surgical procedure is simple, and the results are satisfactory.

Adult↗

PubMed1999

Anterior knee pain after intramedullary tibial nailing.

BACKGROUND: Currently, intramedullary nailing is a well-accepted method for treating tibial shaft fractures, but some patients complain of anterior knee pain after surgery. Multiple factors may influence this troublesome complication. METHODS: This was a retrospective analysis of the medical records of 200 patients who were treated with intramedullary nailing after tibial shaft fractures. Sixty-four patients complained of knee pain after surgery. We evaluated the knee pain in relation to the surgical approach, radiographic readings, and the type of nail used. RESULTS: Among the 64 patients, 45 (70%) received central approaches and 19 (30%) received paramedial approaches (p = 0.0002); 46 patients (72%) showed nail protrusions on radiographs and only 18 patients (28%) were without nail impingement (p = 0.0001). Forty-three patients (67%) received Kuntscher nail fixation and just 21 patients (33%) had interlocking nail fixation (p = 0.0015). CONCLUSION: The use of the central patellar tendon splitted approach, nail protrusion observed on radiographs, and the insertion of a non-locking intramedullary nail were all significant risk factors for anterior knee pain after surgery. All these risk factors should be avoided in tibial nailing to decrease the problem of postoperative knee pain.

Fracture Fixation, Intramedullary↗