Biomedical subjects

Da-chuan Xu

Publications and source records attributed to Da-chuan Xu.

10 recordsLinked to original sources

PubMed2006

[Anatomic evaluation the entry point of C2 pedicle screw].

OBJECTIVE: To study the relevant position of C(2) pedicle to C(2) inferior articular process, set up a technique of C(2) pedicle screw placement with the inferior articular process of axis as an anatomic landmark. METHODS: Fifty C(2) bone specimens were used to measure the distance from the sagittal midline to the medial border, the midpoint and the lateral border of C(2) inferior articular process or C(2) pedicle; the width and the height of the C(2) pedicle were also evaluated. The anatomic relation between the measurements data of C(2) pedicle and that of C(2) inferior articular process were analyzed, and the technique of C(2) pedicle screw fixation was established. RESULTS: The medial border of C(2) inferior articular process was averaged (3.67 +/- 0.41) mm lateral to that of C(2) pedicle, and the midpoint C(2) inferior articular process was averaged (1.15 +/- 0.44) mm lateral to the lateral border of C(2) pedicle, respectively. Using the C(2) inferior articular process as landmark, two techniques was established for C(2) pedicle screw placement. The entry point of method A was located in 2 mm medial and superior to the central point of C(2) inferior articular process; the entry point of method B was at the crossing point of the medial border C(2) inferior articular process with the superior quarter of C(2) inferior articular process. CONCLUSIONS: There is a steady anatomic relation between C(2) pedicle and C(2) inferior articular process, the C(2) inferior articular process could be as a convenient key anatomic landmark to determine the location of C(2) pedicle and the position of C(2) pedicle screw entry point.

Axis, Cervical Vertebra↗

PubMed2006

[Rotational malalignment causing patellofemoral complications after total knee replacement].

OBJECTIVE: To study the rotation of femoral component and tibial component with CT and evaluate the relationship between patellofemoral complications and rotational alignment of the components. METHODS: Thirty patients with isolated patellofemoral complications after total knee arthroplasty were compared with 20 patients with well functioning total knee replacements free of patellofemoral complications. The epicondylar axis and tibial tubercle were used as references on CT scans to quantify the rotational alignment of the femoral and tibial components. RESULTS: Patients with patellofemoral complications had excessive combined (tibial plus femoral) internal component rotation, which was directly proportional to the severity of the patellofemoral complications. Mild combined internal rotation (1 degree-4 degrees) was correlated with patellar and lateral tracking tilting, moderate rotation (3 degrees-8 degrees) with patellar subluxation, and severe rotation (7 degrees-17 degrees) with early patellar dislocation or late patellar prosthesis failure. The control group had combined external rotation of 10 degrees-0 degree. CONCLUSIONS: The direct correlation of combined internal component rotation to the severity of the patellofemoral complication suggests that internal component rotation may be the predominant cause of patellofemoral complications in patients with normal axis alignment. CT scans can be used intraoperatively and postoperatively to determine whether the rotational malalignment is present to require revision of one or both components.

Adult↗

PubMed2006

[Anatomic study of the hypoglossal nerve in hypoglossal-facial nerve anastomosis].

OBJECTIVE: To determine the optimal position of hypoglossal nerve in hypoglossal-facial nerve anastomosis and the eligibility of hypoglossal-facial nerve anastomosis with the cervical loop. METHODS: The cervical course and adjacent structures of the hypoglossal nerve were observed on 21 adult cadavers. The hypoglossal nerve and facial nerve were taken from 3 fresh specimens, and the number of the fasciculus and the cross-sectional area of the nerve were measured. RESULTS: The facial nerve trunk were monofascicular with a cross-sectional area of 5.1-/+0.2 (range 4.6-5.7) mm(2). The number of the fasciculus and the cross-sectional areas of the nerve trunk and the fasciculus were 1.6-/+0.8 (range 1-4) mm(2) , 7.5-/+0.7 mm(2) (range 6.8-8.0) mm(2), and 4.7-/+0.6 (4.1-5.5) mm(2), respectively, at the proximal segment of the hypoglossal nerve, 3.6-/+0.5 (1-5) mm(2) , 5.6-/+0.5 (4.9-6.1) mm(2) , and 1.6-/+0.4 (0.9-2.2) mm(2) at the distal segment, and 2.4-/+0.8 (1-3) mm(2), 1.1-/+0.7 (0.6-2.2) mm(2), and 0.5-/+0.3 (0.3-1.2) mm(2) at the cervical loop. CONCLUSION: The cervical loop is inadequate for facial nerve anastomosis and the proximal segment is large enough to allow partial harvesting of the hypoglossal nerve for neurotisation of the facial nerve.

Anastomosis, Surgical↗

PubMed2006

[Pelvic artery representation on three-dimensional reconstructed multislice spiral CT images: variability between the young and the elderly].

OBJECTIVE: To analyze the variability in pelvic artery representation on three-dimensional reconstructed multislice spiral CT images between young adults and the elderly. METHODS: Eight young adult volunteers from the medical staff and 8 elderly people undergoing regular coronary artery examination, who were all free of coronary artery disease and diabetes mellitus, were enrolled in this study. After administration of the contrast agent through the median cubital vein at 3.5 ml/s, the subjects underwent contrast-enhanced CT angiography of the pelvic arteries utilizing a 16-row multislice spiral CT. The images were collected and processed with volume reconstruction (VR) technique for three-dimensional reconstruction to distinguish the arteries and their branches. RESULTS: Good visualization of the pelvic artery was observed on the reconstructed CT images of the young subjects, which revealed in detail up to the third- and even the fourth-order vessels, and the arteries were smooth and had plenty of branches; but in the elderly only the second- or third-order vessels were shown, and the arteries appeared stiff with only a few branches. CONCLUSIONS: Compared with the young adults, the elderly have generally poor visualization of the pelvic arteries on three-dimensional reconstructed multislice spiral CT images possibly in association with atherosclerosis and the functional deterioration of the blood vessels in the latter, which is relative to vascular morphologic changes, suggesting the necessity of studying the pelvic vessels with developmental and functional methods.

Adult↗

PubMed2006

[Evaluation of perioperative blood loss following total knee arthroplasty].

OBJECTIVE: To evaluate perioperative occult blood loss following total knee arthroplasty (TKA). METHODS: A retrospective analysis of 40 patients undergoing TKA was conducted to calculate the mean blood loss and occult blood loss according to Gross formula. RESULTS: The mean total blood loss was 1538 ml in these cases with occult blood loss of 791 ml. In patients with autologous blood transfusion, the mean total blood loss was 1650 ml with occult blood loss of 786 ml. In patients without autologous blood transfusion, the mean total blood loss was 1370 ml with occult loss of 798 ml. CONCLUSION: TKA often results in large volume of occult blood loss in the perioperative period which can not be fully compensated by autologous blood transfusion, and additional blood supply is needed for maintenance of the circulating volume.

Aged↗

PubMed2005

[Anatomic identification of the location of the pedicle of atlas with the lateral mass of C2 to C4 as the landmark].

OBJECTIVE: To study the relevant position of the pedicle of C1 to the lateral mass of C(2-4), set up an identification technique for the entry point decision of C1 pedicle screw by using the lateral mass of C(2-4) as anatomic landmarks. METHODS: Twenty cadaver specimens were used to measure the distance from the sagittal midline of spine to the medial border, the midpoint and the lateral border of C1 pedicle or the lateral mass of C2, C3 or C4. The anatomic relation between the measurements data of C1 pedicle and that of the lateral masses of the cervical vertebrae were analyzed, and the technique of C1 pedicle screw fixation was established. RESULTS: The average medial border of the lateral mass of C2, C3 and C4 was 0.37 mm, 0.27 mm and 0.24 mm lateral to that of C1 pedicle, the average midpoint of the lateral mass of C2, C3 and C4 was 1.18 mm, 1.41 mm and 1.74 mm lateral to that of C1 pedicle, and the average lateral border of the lateral mass of C2, C3 and C4 was 1.96 mm, 2.54 mm and 3.24 mm lateral to that of C1 pedicle, respectively. CONCLUSION: There is a steady anatomic location relation between C1 pedicle and the lateral mass of C2, C3 or C4. As well as the lateral mass of C2, the lateral mass of C3 or that of C4 could be convenient anatomic landmarks to determine the location of C1 pedicle and the position of C1 pedicle screw entry point.

Adult↗

PubMed2003

Brow fat pad flap transfer for repairing depressed deformity of the upper eyelids.

OBJECTIVE: To study the new surgical approach to repair depressed deformity of the upper eyelids by transferring brow fat pad flap that retains blood supply and similar construction with the orbital septum. METHOD: An incision was made in the inferior margin of the brow to dissect and expose the brow fat pad under the orbicular muscle of the eye and frontal muscle plane in the lateral superior orbit, and the flap was removed from above the periosteum and pedicled under the orbital rim. Through the incision in the double-eyelid fold, a tunnel was dissected upward from the plane under the orbicular muscle to reach the brow incision. The brow fat pad flap was then turned over to cover the deformity, followed by fixation and suture of the flap and a double-eyelid operation. RESULT: Four patients with the upper eyelid deformity were successfully treated using this new procedure with satisfactory results and no complications were encountered. Fat absorption was not observed in the one-year follow-up. CONCLUSION: This procedure has the merits that (1) the fat tissue transferred to the recipient site has blood supply, thus fat absorption is prevented and the surgical results can be almost permanently maintained; (2) The similarity between the construction of the brow fat pad and the orbital septum fat may ensure better result with more natural look of the eyelids; (3) The donor site is adjacent to the recipient site to facilitate the brow fat pad transferring; (4) The operation leaves no obvious scars at the donor site.

Adult↗

PubMed2003

[Study and clinical application of auto-compressive and anti-rotate intramedullary nail].

OBJECTIVE: To design an auto-compressive and anti-rotate intramedullary nail (ACACIN) and to evaluate the preliminary clinical efficacy on fixing adult femur fracture. METHODS: From January 1998 to June 2001, 23 patients with femur fracture were stabilized with auto-compressive and anti-rotate intramedullary nail. 2-4 elastic blocks were installed into the proximal and distal different distance of quincunx nail to defend rotate and axis compress. RESULTS: Fracture healing were obtained in all 23 patients treated with auto-compressive and anti-rotate intramedullary nail, the time of fracture healing was 6-13 weeks in 21 cases and 15-22 weeks in 2 cases of old fracture. There was no complication related to infection, nail break, abnormal union and joint ankylosis. The results were excellent in 19 cases, good in 3 cases, and moderate in 1 case according Kolmert's criterion for function; the effective rate was 95.7%. CONCLUSION: Auto-compressive and anti-rotate intramedullary nail has a suitable radian for adult femur, can afford stable fixation, anti-rotate and axis compress.

Adolescent↗

PubMed2003

[Prevention of the zygomatic branch of the facial nerve in rhytidectomy: an anatomical study].

OBJECTIVE: To investigate the anatomical distribution of the zygomatic branch of the facial nerve and discuss its clinical significance in the rhytidectomy. METHODS: The distribution of the zygomatic branch of the facial nerve was observed on 30 halves of the fifteen candaveric specimens (10 antiseptic cadaveric specimens and 5 fresh cadavers). RESULTS: The zygomatic branch made its way through the upper or the anterior border of the parotid gland, giving rise to 2 or 3 rami, which could be divided into the superior and the inferior rami. The superior rami, which were thin and superficial, crossed the zygomatic arch at its inner one-third or ran along the inferior margin of the zygomatic arch, and then entered beneath the zygomatic ligaments. The inferior rami were comparatively thick and deep, lying 1.0+/-0.3 cm inferior to the superior rami. The inferior and superior rami joined each other on the surface and deep side of the zygomatic major muscle. CONCLUSION: In the prevention of the zygomatic branch damage in rhytidectomy, the areas where caution should taken were the anterior border of the zygomatic major muscle in sub-SMAS dissection and the zygomatic arch in the subperiosteal dissection. The sharp dissection and excess tension should be avoided to reduce the nerve injury.

Adult↗

PubMed2003

[Observation of blood supplies system to mandible in transparent specimen].

OBJECTIVE: To search for a direct observation method in blood supply system of mandible. METHODS: Six specimens of mandible were made transparent specimens after the vascular system was perfused with Chinese ink from the common carotid artery, and the blood supply system of mandible were observed and analyzed. RESULTS: The distribution of mandibular arteries was distinctly demonstrated in transparent specimens. The normal mandible receives its blood supply from the inferior alveolar artery and the periosteal vessel meshwork. CONCLUSION: The transparent specimen is an effective observation method in blood supply system of mandible.

Female↗