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Biomedical subjects

Hung-Chi Chen

Publications and source records attributed to Hung-Chi Chen.

At least 55 records · Page 3Linked to original sources
PubMed2004

Adequate venous drainage: the most critical factor for a successful free jejunal transfer.

Reconstruction of the cervical esophagus with free jejunum can yield excellent functional results. Flap survival alone, however, does not guarantee satisfying functional outcomes. Critical factors that determine the level of function of the flap include the duration of ischemia and degree of venous congestion. An attempt is made in this study to evaluate the degree that these 2 factors influence outcome and to establish safe methods for avoiding suboptimal functional results. Out of 71 patients that underwent free jejunal transfer for the reconstruction of the cervical esophagus between January 1995 and December 1999, 60 patients with available chart records were included into this study. A retrospective chart review was performed on all 60 patients to evaluate the degree of venous congestion in those patients and the choice of recipient veins and method of anastomosis of those veins (end-to-end versus end-to-side). A more detailed review was performed on the 8 patients that underwent reexploration and detailed history, operative method, ischemia time, choice of recipient vessels, technique of anastomosis, immediate postoperative course, and outcome were determined. Following exploration of the flaps, all flaps survived. Two developed partial necrosis. When smaller veins were used as recipient vessels, the chances of venous congestion were found to be higher than when larger recipient veins were used (chi2 analysis, P <0.02). Method of anastomosis and previous radiotherapy were both found to be significant determinants of venous congestion (chi2 P <0.05 for both). Venous problems accounted for 87.5% (7/8) of all reexplorations. In 75% (6/8) of the reexplored patients, pharyngocutaneous fistula formation or stricture formation was noted.The degree of venous congestion and previous radiotherapy are factors that influence the functional outcome of free jejunal flaps. Proper selection of the recipient veins is a critical factor in providing adequate venous outflow and minimizing venous congestion. End-to-side anastomosis to large vessels is a more reliable method that was found to have a significant influence on minimizing venous congestion and is a useful method for the salvage of venous congested flaps.

Adolescent↗
PubMed2004

Sixty-five clinical cases of free tissue transfer using long arteriovenous fistulas or vein grafts.

Traumatic limb injuries requiring free tissue transfer for coverage, often lack healthy recipient vessels adjacent to the defect. In these patients, vein grafts are required to bridge the gap of either the artery, vein or both. For the latter situation, a temporary arteriovenous fistula (AVF) can be created and allowed to mature and then divided and used as recipient artery and veins for the free flap. These cases are challenging and several variables including vein graft length, vein graft diameter, and arterial inflow affect the patency of the vessels and the final outcome of the reconstruction. Sixty-five defects were reconstructed with free tissue transfers using vein grafts of significant length (>20 cm for the arterial gap). The ipsilateral or contralateral great saphenous veins were used for vessel lengthening in all cases. Inflow arteries were either major arteries (superficial femoral, popliteal or brachial), or lesser arteries (sural, anterior or posterior tibial, thoracodorsal, or superior gluteal). The patients were divided into those that underwent AVF followed by free tissue transfer in two stages (n = 6), AVF followed by free tissue transfer in one stage (n = 28) and patients that underwent vein grafting for the arterial defect only with (n = 6) or without (n = 25) a simultaneous bypass graft for lower limb revascularization. In the two-stage AVF group, the rate of occlusion of the graft after AVF creation was 50% (3/6); re-exploration rate was 33.3% (2/6); free flap failure rate was 33.3% (2/6); and limb salvage rate was 83.3% (5/6). In the one-stage AVF group: re-exploration rate was 28.6% (8/28); free flap success rate was 89.3% (25/28); and limb salvage rate was 92.9% (26/28). In the long vein graft group for arterial defects only: re-exploration rate was 25.8% (8/31); free flap success rate was 96.8% (30/31); and limb salvage rate was 87.1% (27/31). In patients where the graft was anastomosed to a major artery the re-exploration rate and free flap failure rate were 22.4% (11/49) and 8.2% (4/49). In patients where the graft was anastomosed to a lesser artery, the re-exploration rate and free flap failure rate were 43.4% (7/16) and 12.5% (2/16). The limb salvage rate was comparable in both groups (89.8%, 44/49, versus 87.5%, 14/16). In all groups, patients undergoing re-exploration were noted to have a an arterial gap of 31.78 cm as compared with the patients that did not require re-exploration which had an arterial gap of 26.26 cm. Vein grafting for bridging vascular defects is a safe procedure when proper indications and techniques are followed. Although a longer graft length seemed to be associated with a higher re-exploration rate, there was no statistical significance. One-stage AVFs can be used with good results, however, two-stage AVFs are associated with a high graft occlusion rate, wound failure rate and limb amputation rate. In all cases, a large caliber graft such as the great saphenous vein provided a large (relatively low resistance) conduit for bridging the defect.

Adolescent↗
PubMed2004

Immediate toe transfer following index finger amputation for extensive giant cell tumor of the tendon sheath with intraosseous invasion.

Giant cell tumor of the tendon sheath (GCTTS) is the second most common benign tumor of the hand. Although bony indentation from external compression by the GCTTS is frequently seen on x-ray film, the intraosseous invasion is relatively rare and is a sign for high recurrence. We present a woman with extensive GCTTS located in the left index finger at the level of distal interphalangeal joint. X-ray films revealed multiple osteolytic cystic cavities in the shaft of the middle phalanx. Amputation of the index finger at the base of the middle phalanx was performed because of extensive bony involvement and concern about possible recurrence from inadequate excision. Her left second toe was transferred to replace the amputated index finger in the same session. Follow-up examination at 15 months postoperative revealed good function and appearance of the reconstructed index.

Amputation, Surgical↗
PubMed2003

Critical oropharyngocutaneous fistulas after microsurgical head and neck reconstruction: indications for management using the "tissue-plug" technique.

Despite advances in head and neck reconstruction with free-tissue transfer techniques, oropharyngocutaneous fistulas continue to present challenging and potentially lethal complications. The authors present a system for prioritizing these fistulas and the surgical management of nine patients in whom critical fistulas developed after microsurgical head and neck reconstruction. The indications for aggressive management of these fistulas were primarily dependent on their location. Three peristomal and six midneck fistulas were considered critical because of the risk of aspiration pneumonia and carotid artery blowout, respectively. Fistulas located in the submental and/or submandibular region were considered noncritical and were managed conservatively. Using the concept of a "tissue plug" for fistula repair, a dermal component (i.e., a deltopectoral or pectoralis major pedicled flap) is guided through the fistula, and with external traction the tissue "plugs" the tract. No sutures are placed directly in the surrounding friable tissue. There were no partial or total flap losses. There were two fistula recurrences in patients who had received postoperative radiation therapy. One of these recurrences was due to tumor recurrence within the previous fistula and was managed with palliative measures. The other fistula recurrence was closed with a local-flap procedure on an outpatient basis. All patients resumed oral feeding, except for the patient in whom tumor recurrence was suspected. This tissue-plug technique can be used in the management of critical peristomal and/or midneck oropharyngocutaneous fistulas not only to obliterate the tract but also to augment volume and vascularity in already damaged, ischemic, and deficient tissue.

Cutaneous Fistula↗
PubMed2003

Chimeric flap in clinical use.

With the development of modern microsurgical reconstruction, there are several alternative methods for the complicated head and neck defect or injured extremity. The double-paddled flap, double flaps, and double flap with vascular flow-through linkage are good tools for extensive wide, composite, and three-dimensional defects. When faced with a difficult reconstruction, the expense, morbidity of the donor site, and operative time must be taken into consideration. Compared with other combined composite flaps and other methods, the chimeric flap has many advantages including: easy three-dimensional insetting, acceptable aesthetic appearance, reduced donor site morbidity, design with the least effort and operation time, and one pair of recipient vessel. The disadvantages of the chimeric flaps include: the variation of perforators, the requirement of a learning curve, and, sometimes, the need for a second venous drainage or shifting to double flaps. Overall, in selected cases, the chimeric flap is a good option for the reconstruction of extensive, composite, and three-dimensional defects.

Bone and Bones↗
PubMed2003

Use of the free vastus lateralis flap in skull base reconstruction.

Free flaps in skull base reconstruction are indicated for providing an effective separation of the intracranial cavity from the oronasal space, for eliminating a dead space, and for the treatment of established wound complications such as dural exposures and cerebrospinal fluid leaks. Seven patients with cranial base defects underwent reconstructions using a free vastus lateralis muscle flap. In two cases, a vastus lateralis flap was raised to incorporate the anterolateral thigh skin as a myocutaneous flap. In four cases, a free flap was indicated for reconstruction following tumor ablation, and in three cases, for the resolution of wound or cerebrospinal fluid leak complications following previous cranial base surgery. All flaps were successful, with no partial failures. In those patients undergoing tumor ablative surgery, the cranial cavity was effectively sealed from the oronasal cavity. Patients with established wound complications following previous cranial base surgery had a complete resolution of their symptoms. This report discusses the suitability of the vastus lateralis flap for skull base reconstruction in terms of the availability of adequate muscle volume to fill dead space, vascularized fascia to augment dural repairs, and the freedom to use skin if required for internal lining or external skin cover. This flap also provides an extremely long pedicle, allows simultaneous flap harvest, and has low donor site morbidity.

Adult↗
PubMed2003

Complications after reconstruction by plate and soft-tissue free flap in composite mandibular defects and secondary salvage reconstruction with osteocutaneous flap.

Reconstruction of composite defects of the mandible is a challenging problem. Although the use of an osteocutaneous free flap, alone or in combination with another soft-tissue free flap, is generally accepted to be optimal, the bony reconstruction is sometimes undervalued, especially when the cancer is advanced. In such situations, reconstruction is often performed with a reconstruction plate covered with a soft-tissue free flap. Between January of 1997 and July of 2000, 80 patients with composite or extensive composite oromandibular defects underwent treatment with a reconstruction plate and a soft-tissue free flap. All of the patients were male, and the ages of the patients at the time of treatment ranged from 32 to 78 years (mean, 51 years). Tumors were classified as stage IV in 56 patients (70 percent), whereas the remaining 24 patients (30 percent) had recurrent carcinomas. The titanium mandibular reconstruction system manufactured by Stryker (Freiburg, Germany) was used to bridge the mandibular defects. The soft-tissue free flaps used for wound and plate coverage were as follows: anterolateral thigh flap (n = 75), radial forearm flap (n = 3), transverse rectus abdominis myocutaneous flap (n = 1), and tensor fasciae latae flap (n = 1). Five patients with recurrent carcinomas and 10 with stage IV carcinomas (18.75 percent) died 2 to 6 months after the operation and were excluded from the study. The remaining 65 patients were monitored for an average follow-up period of 22 months (range, 6 to 40 months). During that period, one or more complications occurred for 45 patients (69.2 percent). Plate exposure was the most common complication and was observed for 30 patients (46.15 percent). Twenty of the 65 patients (30.8 percent) required secondary salvage reconstruction with a fibula osteoseptocutaneous flap. The decision to perform a secondary salvage procedure was based on the general health of the patient, the extent of local disease, and the severity of the complications. Patients underwent salvage operations after an average of 11.5 months (range, 6 to 26 months). The major reasons for the second operation were as follows: reconstruction plate exposure (n = 12), soft-tissue deficiency and mandibular contour deformation of the lateral face (n = 7), intraoral contracture and lack of a gingivobuccal sulcus (n = 6), trismus (n = 4), and osteoradionecrosis of the mandible (n = 2). The total flap survival rate was 90 percent (18 of 20 free flaps). In two cases, the skin paddles of the fibula osteoseptocutaneous flaps exhibited partial failure and were revised with pedicled pectoralis major and deltopectoral flaps. The reconstruction plate and free soft-tissue flap procedure for the reconstruction of composite defects of the oromandibular region has many late complications, which eventually necessitate reconstruction of the mandible with an osteocutaneous free flap.

Adult↗
PubMed2003

The use of ultrasonography in preoperative localization of digital glomus tumors.

Small glomus tumors of the digits of the hand are difficult to excise and may be associated with relatively high rates of recurrence. This study was designed to prospectively evaluate the utility of preoperative ultrasound localization of such tumors to facilitate removal and to reduce recurrence rates. During a 5-year period, 34 patients clinically diagnosed with glomus tumors involving their digits were examined with high-resolution ultrasonography (5 to 9 MHz). Color duplex sonography was further applied if flow characteristics were identified. The ultrasound-predicted and actual intraoperative sizes were correlated and analyzed using the paired t test. Patients were followed for 1 to 6 years, and results were documented. Sonography showed a hypoechoic nodule with prominent vascularity between the nail body and the dorsal cortex of the distal phalanx in all subungual tumors. Complete resection was possible in all 35 glomus tumors, with assistance by accurate preoperative ultrasound localization. There was no long-term recurrence among the 29 patients available for evaluation 1 to 6 years postoperatively. Ultrasonography has great advantages in defining the exact location and size of the glomus tumor preoperatively. Prior knowledge of the exact site and size of the glomus tumor facilitates excision and appears to reduce rates of recurrence. The collaboration between hand surgeons and radiologists is useful to successfully treat glomus tumors of the digit.

Adult↗
PubMed2003

US-guided catheter drainage of postoperative head and neck fluid collections.

PURPOSE: To analyze results of percutaneous catheter drainage of large fluid collections in the head and neck region noted in the immediate postoperative period. MATERIALS AND METHODS: Thirty-four consecutive patients with 41 large fluid collections in the head and neck detected 7-10 days after oncologic surgery underwent percutaneous catheter drainage. There were 29 men and five women, with a mean age of 52.2 years (95% CI: 47.8-56.7). Each patient had a surgical drain placed in the posterior neck triangle; three patients had low-grade fever and six had diabetes at the time of percutaneous catheter drainage. Conventional management consisting of serial needle aspirations at bedside followed by pressure dressing failed in 15 of 34 patients (44%). Ultrasound-guided drainage was performed and catheters were connected to vacuum balls for continuous suction drainage. RESULTS: The average fluid volume estimated by sonographic measurement was 84 cm(3) (95% CI: 57-112 cm(3)). The fluid content was serosanguinous in 46% (19 of 41), uncoagulated blood in 32% (13 of 41), pus in 15% (six of 41), and saliva in 7% (three of 41). The mean duration of catheter drainage was nine days (95% CI: 7-10 d) and mean fluid drainage was 287 mL (95% CI: 188-387 mL). Ninety-one percent of patients (31 of 34) were successfully treated with initial catheter drainage. Three patients had recurrent fluid collections at the same locations: two were treated with repeated catheter insertions and one required a limited open drainage. No complication related to catheter drainage was noted at 6-month follow-up. CONCLUSION: Percutaneous catheter drainage is effective for large fluid collections in the head and neck region noted in the immediate postoperative period irrespective of contents.

Drainage↗
PubMed2003

A new method for vaginal reconstruction using a pedicled jejunal flap.

A technique for vaginal reconstruction is described that uses a pedicled jejunal flap. A neovagina was constructed using a segment of jejunum based on the fourth branch of the superior mesenteric artery. This provided an excellent result with adequate length, without the need for a lubricator or stent. Hypersecretion has not been observed.

Adult↗
PubMed2003

Using a Y-shaped vein graft with drain-out branches to provide additional arterial sources for free flap reconstruction in injured lower extremities.

BACKGROUND: Reconstruction of the distal lower extremity with poor arterial circulation is a challenge for reconstructive surgeons, especially when a microsurgical free tissue transfer is necessary. One may face the problem of having no suitable recipient artery to be used except the main one. To overcome this difficult situation, utilization of a Y-shaped vein graft (YVG) was developed. METHODS: We report on 3 successful reconstructions of the lower extremities with free flaps using YVG to supply the arterial inflow and in which the distal circulation of the lower extremity was preserved at the same time. The therapeutic goals, design, surgical technique, and outcomes are clarified. The indications, advantages, and disadvantages are also discussed. RESULTS: All 3 patients achieved successful reconstruction of the affected limbs with uneventful surgery. Special microsurgical skills are unnecessary in this method. It can provide an additional arterial source, which is useful and reliable for revascularizing various kinds of free tissue. Utmost care must be taken to examine the direction of flow during harvesting since only the drainout branches can serve as an ideal YVG. CONCLUSION: We concluded that Y-shaped vein grafting is a good alternative technique to achieve free flap reconstruction of a distal lower extremity with simultaneous preservation of the distal circulation in selected difficult cases.

Ankle Injuries↗
PubMed2002

Microsurgical reconstruction of the esophagus using supercharged pedicled jejunum flaps: special indications and pitfalls.

This report outlines a microsurgical technique for total esophageal reconstruction in situations in which conventional methods using stomach or colon are not available. Eleven patients with corrosive injury and one patient following tumor resection underwent total esophageal reconstruction in a two-stage procedure. In the first stage, skin flaps or free jejunal transfers were used for the cervical reconstruction. In the second stage, supercharged pedicled jejunum flaps placed subcutaneously were used for thoracic esophageal replacement. The study included one male and 10 female patients, with a mean age of 38.4 years. The mean follow-up period was 78.9 months. All patients had one or more complications that required revisional surgery. Pedicled myocutaneous flaps were used to close fistulas or chronic wounds in four patients. The cervical skin tube in two patients and the jejunum in another two patients required shortening because of redundancy. Four patients had dysphagia caused by neck contractures, which were released. Two patients developed pharyngoesophageal strictures that required further free skin flaps for release. Two patients had reflux because of blind pouches arising from the original esophagus and required thoracotomy for removal. At long-term follow-up, all patients are fully rehabilitated and have resumed an oral diet with significant weight gain. Compared with lifelong jejunostomy feeding and its associated psychosocial disadvantages, the authors' experience demonstrates that the application of microsurgical techniques to fully reconstruct the esophagus is of considerable benefit to this difficult patient group.

Adult↗
PubMed2002

Behavior of free jejunal flaps after early disruption of blood supply.

We describe three free jejunal flaps that lost their axial blood supply in the early postoperative period--two flaps on the 7th day and the third on the 17th day. At 7 days, reestablishment of axial blood flow was essential to flap survival, whereas after 17 days, vascularization from the recipient bed was adequate to maintain viability. Based on these observations, a conservative approach to flap salvage for cases with pedicle disruption at 17 days or later is recommended.

Adult↗
PubMed2002

Salvage of right colon interposition by microsurgical venous anastomosis.

Venous insufficiency of a right colon interposition in esophageal reconstruction can be a fatal complication resulting in total failure. A case is presented of the salvage of the right colon interposition by additional microsurgical venous anastomosis to relieve the problem of venous stasis. The outcome was successful in a young patient with a complicated medical history.

Anastomosis, Surgical↗
PubMed2002

In vivo evaluation of leucocyte dynamics in cremaster muscle in rats after exposure to cigarette smoke.

This experiment was designed to examine the effects of chronic cigarette smoking on the microcirculation immediately after exposure to smoke for two, four, and six weeks and after withholding smoke for two weeks from those previously exposed for four weeks. The mean (SD) rolling leucocytes at two, four, and six weeks were 11.10 (1.8), 23.7 (2.3), 40.2 (3.9) (p < 0.001). The rolling leucocytes after smoking for four weeks and then having smoke withheld for two weeks was 9.6 (1.4). The mean adherent leucocytes were 5.0 (0.7), 7.5 (1.1), 12.6 (1.8) (p < 0.001). The adherent leucocytes after smoking for four weeks and then having smoke withheld for two weeks was 3.5 (0.5). Our results confirm those of many previous studies of the adverse effects of cigarette smoking, and also that those deleterious effects are time-dependent. The reversibility of the deleterious effect of cigarette smoking after cessation of cigarette smoking before face-lift or flap reconstruction is at least two weeks. This information is also important for clinical management of patients who smoke and who are scheduled for face-lift and flap reconstruction. Two weeks without cigarettes is a necessary period for successful elective plastic surgery.

Animals↗