Finite element analysis for self-made femoral head brace device in the treatment of early femoral head necrosis / 中国组织工程研究

BACKGROUND: Core decompression for early adult ischemic necrosis of femoral head gets the identity of most scholars, but the postoperative femoral head easily experiences collapse. How to prevent collapse is still a problem to be solved currently. OBJECTIVE: To perform biomechanical analysis of femoral head ischemic necrosis by using the finite element method and to provide biomechanical basis for the treatment of early adult femoral head necrosis. METHODS: One fresh femur specimen died of accidental death in youth and young adults was obtained, and no deformity or fracture was found. X-ray confirmed that it did not have tumor or osteoporosis. Spiral CT was used to scan normal femoral head and neck, pulp core decompression of femoral head and neck, brace device placement and bone-graft of femoral head and neck for acquiring image data from the proximal to distal vertical longitudinal axis. Scanning data were input in the Mimics software. Finite element method was utilized for biomechanical analysis of femoral head and neck of three models. RESULTS AND CONCLUSION: (1) The stress dispersal and downward conduction of normal femoral head was concentrated in the shaft of the femur and the tensile stress was concentrated in the rotor socket. (2) After pulp core decompression, the stress concentration, displacement and strain increased in the weight-bearing area of femoral head. (3) The stress of the internal bracing was similar to that of normal femoral head. (4) The stress of weight bearing area of femoral head is concentrated, and the strain is increased, so that weight bearing area is easy to collapse after pulp core decompression. The more stress distribution, more bearing load and less strain of implant and bone graft model, are conformed to the normal mechanical properties of the normal femoral head and neck.

Biomechanical study of compressive strength distribution on the whole spine endplates / 医用生物力学

Objective To study distributions of the compressive strength on the whole spine endplates by measuring the compressive strength at different locations of the whole spine endplates. Methods Indentation tests were performed at 49 locations in 225 bony endplates of intact human vertebrae (C3 S1) from 5 fresh male specimens to record the failure loads. Results (1) For the whole spine endplates, failure loads of the cervical and lumbar spine were found to be higher than those of the thoracic spine (P<0.01).The failure load was first decreased from C3 to C7 before increasing to T1, and then dropping through T7 and rising again from T8, reaching the maximum at L4, and dropping at L5 before increasing again at S1. (2) The failure load at inferior cervical endplates was significantly higher than that at superior endplates except at C5 and T1 (P＜0.05). (3) Within the intervertebral space, the cranial endplates had a higher yield stress than the caudal endplates except at C5/6, T12/L1 and L5/S1. (4) Failure loads were generally increased from the central to peripheral zones (P＜0.05). (5) For different angular points, failure load distributions were found among the endplates (P<0.01). (6) Distributions of the compressive strength on the endplates varied significantly within the whole spine（P<0.01）. It was found that at C3/4, the failure load at posterior was higher than that at anterior, but at C5/6, the failure load at posterior and anterior was balanced. At T1, the failure load was found to be higher at posterior again, until passing through T2 5, and at T6 L3, the failure load at anterior was higher than that at posterior, and balanced between the anterior and posterior again at L4. At L5 S1, the failure load at posterior was higher than that at anterior. Conclusions The strength distributions on the endplates varied significantly at different locations within the whole spine, which was closely correlated with the physiological curve of the spine. The failure load at inferior endplates was higher than that at superior endplates and it was increased from central to peripheral zones. Within the intervertebral space, the compressive strength at cranial endplates was higher than that at caudal endplates.

In vitro study of directional inducible differentiation of inner ear hair cells from human adipose-derived mesenchymal stem cells / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To explore the feasibility of directionally inducing human adipose-derived mesenchymal stem cells (hAD-MSCs) towards inner ear hair cells.</p><p><b>METHODS</b>Mesenchymal stem cells from human adipose tissue were isolated, purified and cultured in vitro. hAD-MSCs were induced to neural stem/progenitor-like cell, and then co-cultured with embryonic chick otic vesicle cells. Processed hAD-MSCs were tested by immunostaining to ascertain whether they expressed characteristic hair cell markers.</p><p><b>RESULTS</b>Morphologically, hAD-MSCs were induced to differentiate into neural stem/progenitor cells and expressed specific neural markers. After being co-cultured with embryonic chick otic vesicle cells, hAD-MSCs expressed specific surface markers of inner ear hair cells.</p><p><b>CONCLUSIONS</b>hAD-MSCs can be directionally induced to differentiate towards hair cell-like cells in vitro.</p>

Biomechanical analysis of artificial intervertebral disc in a 3-dimensional finite-element model / 中南大学学报(医学版)

OBJECTIVE@#To evaluate the mechanical properties of artificial lumbar intervertebral disc by finite-element (FE) analysis, to predict the mechanical influence of loading on the prosthesis after placement, especially after the long-term employment,and to offer the mechanical basis and technological means for the design optimization.@*METHODS@#A 3-dimensional solid model was built according to the geometry of the prosthesis; finite-element analysis was applied to determine the effect of the implanted artificial disc prosthesis on the biomechanical behavior; and the data of its mechanical responses were calculated in 3 compression modes which simulated its different load conditions in vivo. Simulations were conducted in a new specially designed manner, preferably simulated load conditions in vivo.@*RESULTS@#A finite-element model was established by generating mesh out of the prosthesis geometry. The analysis was conducted in employing models of the disc prosthesis under 3 types of emulational realism loading conditions, obtaining the distributing characteristics and data of displacement-stress-strain-energy in the structure, which are difficult to measure exactly by conventional methods.@*CONCLUSION@#Implanted loading strongly influences prosthesis in its internal distribution of displacement-stress-strain-energy in the structure, suggesting that the disc prosthesis allows correctly reproducing a profitable motion and cushion at the implanted level. Predictive wear may occur in special parts according to the designed prosthesis mechanical structure. When implanting an artificial disc, proper size should be taken in choosing disc and the higher core could provide better mechanical characteristics. The Results may assist in optimizing artificial lumbar disc replacement primarily from a biomechanical point of view.

Internal fixation with T type titanium plate for volar Barton's fracture / 中南大学学报(医学版)

OBJECTIVE@#To evaluate the operative method and the clinical efficacy of volar Barton's fracture treated by internal fixation with T type titanium plate.@*METHODS@#We performed the operation of the open reduction and internal fixation with T type titanium plate in 18 patients with volar Barton's fracture.@*RESULTS@#The 18 patients were followed up after the operation at the average time of 13 months (6 to 31 months). X radiographs showed that all patients achieved solid bone union. Mehara's evaluation for volar Barton's fracture revealed excellent outcome in 12 patients, good in 5 patients, and fair in 1 patients. The excellent and good rate of clinical results was 94.4%. X-radiographs showed that the volar tilting angle was 8-18 (mean=11.0) degree, and the ulnar inclining angle was 16-26 (mean=22.4) degree. There was no shortening of the radius.@*CONCLUSION@#The operative treatment with titanium T type plate fixation for volar Barton's fracture is in favor of fracture anatomic reduction, solid internal fixation, and catagmatic concrescence. It is beneficial for functional recovery of the wrist at the utmost. The outcome in the near future is satisfactory. It is an ideal method for volar Barton's fracture.

Design and manufacture of the static 3 dimensional screw-plate system and its matching tools / 中南大学学报(医学版)

OBJECTIVE@#To design and manufacture a new type instrument and its matching tools for the proximal femur.@*METHODS@#A new type instrument of subtrochanterical fracture-static 3-dimensional screw-plate system(STDSP)was designed and manufactured. The different types of accessory instruments which adapted to STDSP,the aiming guide, and the accessory tools were also designed and manufactured, and they were tested on bones.@*RESULTS@#STDSP included 3 special lag screws and 1 anatomic plate. The lag screws distributed in femoral neck like "or"shape. There was 135 degree between the lag screws and femoral shaft. The shape of the plate was similar to the anatomic structure of the proximal thighbone. The posterior screw was stably connected to the plate. The plate was affixed crosswise to the lateral and anterior side by bicortical screws. The aiming guides and all kinds of accessory tools could help to install STDSP exactly and conveniently,which was verified on cadavers and X-ray photographs.@*CONCLUSION@#STDSP has the function of dynamic compressing in 3-dimensional space, and can match with the structure of the proximal femur preferably. STDSP may be a suitable instrument to the subtrochanteric fractures. The accessory apparatus of STDSP has simple configuration,and can let the STDSP be installed accurately, conveniently and rapidly.

A controlled clinical trail of perioperative nutritional support of thoracolumbar spinal tuberculosis / 中国骨伤

<p><b>OBJECTIVE</b>To evaluate the influence of perioperative nutritional support on nutritional status of patients with thoracolumbar spinal tuberculosis.</p><p><b>METHODS</b>Forty-eight patients with thoracolumbar spinal tuberculosis (male 25 and female 23, aged from 35 to 60 years, with an average of 48.25 years) were randomized into two groups. Twenty-four patients nutritional support were increased intravenously for 14 days (7 days before and after operation) in experimental group. Twenty-four patients in control group were supplied with routine diet. The body weight, plasma concentrations of albumin and ESR were detected on the 7th day before operation and on the 7th day after operation. The total wound drainage was recorded and compared.</p><p><b>RESULTS</b>Body weight and plasma concentrations of albumin on the 7th day after operation and those on the 7th day before operation were not significantly different in experimental group (P > 0.05). In control group, body weight and plasma concentrations of albumin on the 7th day after operation was lower than those on the 7th day before operation (P < 0.05). The total wound drainage of experimental group was less than that of control group (P < 0.05). ESR on the 7th day after operation was lower than that on the 7th day before operation in two groups (P < 0.05); but the decrease of ESR in experimental group was more than that in control group (P < 0.05).</p><p><b>CONCLUSION</b>Nutritional support is beneficial to alleviating innutrition caused by tubercle bacillus and operation. It can promote the effects of operation and anti-tuberculotic drugs.</p>

Construction of recombinant baculovirus Ac-CMV-hSox9 for gene therapy of intervertebral disc degeneration / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To construct the recombinant baculovirus Ac-cytomegalovirus (CMV)-hSox9 for gene therapy of intervertebral disc degeneration.</p><p><b>METHODS</b>Bac-to-Bac system was used for the construction of baculovirus Ac-CMV-hSox9. The cDNA of hSox9 was first cloned into a plasmid vector under the control of CMV promotor to generate the donor plasmid pFastBacDuljgreen fluorescene protein (GFP)-CMV (pFGC)-hSox9. The resultant plasmid was transformed into DH10Bac cells and then the transformation mixture was spread on Luria-Bertani (LB) agarose culture medium containing isopropyl-beta-D-thiogalactoside (IPTG), X-gal, gentamicin, kanamycin and tetracycline. The white colonies were selected and cultured for amplification, and the hSox9Bacmid DNA was extracted. After verification, recombinant baculovirus Ac-CMV-hSox9 was obtained through transfecting Sf 21 cells. The expression of hSox9 gene in the intervertebral disc cells in rabbits was determined by Western blotting and immunohistochemical staining.</p><p><b>RESULTS</b>Polymerase chain reaction (PCR) confirmed the presence of hSox9 gene in the recombinant baculovirus and the Sf 21 cells transfected by the baculovirus showed the expression of fluorescence protein. Western blotting and immunohistochemical staining analysis indicated that exogenous hSox9 gene was expressed in the disc cells.</p><p><b>CONCLUSIONS</b>The successful construction of the recombinant baculovirus Ac-CMV-hSox9 and the confirmation of the target gene expression provides a novel expression vector system for basic research and clinical treatment of intervertebral degenerative disc disease.</p>

Denaturant gradient gel electrophoresis in the genetic diagnosis of hereditary multiple exostoses / 中南大学学报(医学版)

OBJECTIVE@#To detect the mutations of EXT2 gene in hereditary multiple exostoses (HME) families and to investigate the sensitivity of denaturant gradient gel electrophoresis (DGGE) in screening the mutations in EXT2 gene.@*METHODS@#Five HME families and 3 sporadic patients were screened for the mutation detection in all exons of EXT2 gene covering the coding sequence and the flanking intronic sequence by DGGE, and DNA sequencing was performed for products with abnormal conformation.@*RESULTS@#Among these HME patients, we found 2 disease-causing mutations: A313T (nonsense mutation) and 319 insGT (frameshift mutation).@*CONCLUSION@#Two mutations of EXT2 gene are identified in the sample. DGGE can be an ideal choice for gene diagnoses of HME.

Integrity of lumbar facet joint and curative effect after a lumbar intervertebral disc operation / 中南大学学报(医学版)

OBJECTIVE@#To analyze the relation between the clinical outcome and the integrity of the facets after a lumbar operation,and to provide a reference for choosing operative method and clinical prognosis.@*METHODS@#Forty-three patients with complete data underwent uni-segment discectomy were enrolled. There were 3 surgical interventions: open-window discectomy, full or semi-laminectomy. Groups were divided based on the integrity of the facets after the operation, and the clinical symptoms and signs were evaluated using the Japanese Orthopaedic Association Back (JOA) scores at 24-month follow-up.@*RESULTS@#Preoperative JOA scores were not significantly different among the groups (P>0.05). Compared with the facet intact group at 24-month follow-up,JOA scores were descended statistically in total uni-facetectomy group and total uni-facetectomy plus partial opposite facetectomy group (P<0.01).@*CONCLUSION@#Keeping facets integrated plays an important role in achieving good clinical results,and the damage of facet should be avoided in the lumbar operation.

Diagnosis and treatment of postoperative intervertebral infectio / 中南大学学报(医学版)

OBJECTIVE@#To retrospectively explore the diagnosis and treatment of postoperative lumbar intervertebral disc infection.@*METHODS@#Twelve patients who suffered from postoperative lumbar intervertebral disc infection between April 1995 and September 2004 were confirmed doubtlessly by the diagnosis. They were treated with early immobilization combined with early and sufficient antibiotics and adequate corticosteroid. Patients with severe symptoms were managed by percutaneous puncture and washing discectomy such as rising temperature and perivertebral muscle spasm besides nostalgia, and early debridement of all necrotic tissue was done.@*RESULTS@#Six were healed by non-operation and operation in the other 6. All had gotten locomotion with corset after the operation for 6-8 weeks and were followed-up from 6 months to 3 years. They have achieved excellent outcomes.@*CONCLUSION@#When a postoperative disc space infection occurs, early diagnosis and treatment should be undertaken to achieve excellent outcomes.

Clavicular hook plate in the treatment of dislocation of acromioclavicular joint and fracture of distal clavicle / 中南大学学报(医学版)

OBJECTIVE@#To evaluate the curative effects of AO clavicular hook plate in the treatment of dislocation of acromioclavicular joint and fracture of distal clavicle.@*METHODS@#We retrospectively analyzed the clinical data of 39 patients with acromioclavicular joint dislocation or distal clavicle fractures treated with clavicular hook plate: 16 suffered from dislocation of acromioclaviculr joint, 18 suffered from far end collarbone fractures, and 5 patients had both symptoms.@*RESULTS@#The 39 patients were followed up for 12 months averagely. All patients got good reduction and fixation. The acromioclavicular joint subluxation, breakage, and loosening of the clavicular hook plate were not observed. The acromioclavicular joint recovered quickly.@*CONCLUSION@#AO clavicular hook plate is a good choice for acromioclavicular joint dislocation and distal clavicular fracture.

Surgical treatment for lumbar discogenic low back pain / 中南大学学报(医学版)

OBJECTIVE@#To explore the curative effect of surgical treatment for lumbar discogenic low back pain.@*METHODS@#Forty-two patients with lumbar discogenic low back pain were treated with disc excision and lumbar interbody fusion: 12 of them were treated with posterior lumbar interbody fusion (PLIF), 30 with afront lumbar interbody fusion (ALIF). The clinical results were evaluated by pre- and post-operative visual analogue scale (VAS), and the fusion rates of the lumbosacral spine were evaluated by X-ray.@*RESULTS@#The average follow-up period was 18 months, ranging from 6 to 36 months. Low back pain basically disappeared in 11 patients treated with PLIF, with mild back pain in one patient; VAS after the operation decreased significantly in comparison with that preoperatively (P<0.01). Low back pain basically disappeared in 28 patients treated with ALIF; VAS after the operation decreased significantly in comparison with that preoperatively (P<0.01). The fusion rate was 90% in patients treated with PLIF, and 93% in patients with ALIF.@*CONCLUSION@#Disc excision and interbody fusion is effective in the treatment of lumbar discogenic low back pain, but the operation indications should be paid attention to.

Mitochondrial DNA deletion mutations in articular chondrocytes of cartilage affected by osteoarthritis / 中南大学学报(医学版)

OBJECTIVE@#To detect the changes of mitochondrion DNA (mtDNA) sequence in articular chondrocytes of cartilage affected by osteoarthritis and to clarified the pathogenetic mechanism of osteoarthritis.@*METHODS@#We analyzed the mtDNA 4,977 bp deletion mutations of articular chondrocytes in 10 patients with osteoarthritis and 3 normal cartilages using the gap-PCR amplification method. We designed a two round PCR detection method, in which total DNA was isolated from articular chondrocytes as the template of the first round PCR reaction and products from the first round were the template in the second round reaction.@*RESULTS@#The results of the first rounds of PCR reaction showed the mtDNA 524 bp amplified products in the osteoarthritis group and in the corresponding peripheral blood samples were not detected, but the 533 bp products were detected. However,the results of the second round reaction revealed that the 524 bp zones were detected in 2 of the 10 osteoarthritis patients and the corresponding peripheral blood samples were not detected. The 533 bp products were detected in all specimens. The mtDNA 524 bp amplified products in all the normal articular chondrocytes and the corresponding peripheral white blood cells contrast were not detected in both rounds PCR.@*CONCLUSION@#This was the first study to evaluate the mtDNA 4799 bp large fragment deletion mutational accumulation between nt8,470 - nt13,447 of articular chondrocytes in osteoarthritic cartilage. Osteoarthritis may be related to mtDNA mutation of articular chondrocytes.

Clinical analysis of the treatment of reserving limb for patients with malignant bone tumor / 中南大学学报(医学版)

OBJECTIVE@#To investigate the curative effect of the treatment of reserving limb for patients with malignant bone tumor.@*METHODS@#Forty patients with bone neoplasms underwent the operation of reserving limbs. The neoadjuvant chemotherapy was given to all the patients before the operation. After the ablation of the tumor we used the artificial prosthetic replacement,tumor tissue deactivation and reimplant, variant bone and joint transplantation to reserve the limb.@*RESULTS@#All the patients were followed up. The average follow-up time was 34.8 months. Eight patients got complications. And the fineness rate was 72.5% according to functional evaluation standard of Enneking after surgical treatment of bone tumor.@*CONCLUSION@#The operation of reserving limb was an ideal method to cure the malignant bone tumor. The proper operative treatment with neoadjuvant chemo-therapy is helpful to extend the life of the patients and increase the quality of life.

Stability of lumbar spine after artificial disc replacement / 中南大学学报(医学版)

OBJECTIVE@#To determine the influence of artificial disc replacement on the stability of lumbar.@*METHODS@#Ten fresh human cadaveric lumbar spine specimens (9 males, 1 female) were tested. The donors had a mean age of 29.3 years old. The segments were fixed on a special testing device mounted in a universal testing machine. Physiological load with a maximum of 10 Nm was applied in the flexion, extension, right and left side bending. Moments were applied in 6 load steps: 0, 2, 4, 6, 8, and 10 Nm. Linearity migration and angle migration were recorded,and the mean flexibility coefficients were calculated. Four procedures of measurement were performed in every specimen: intact segments, segments after discectomy, segments after the artificial disc replacement, and segments after the artificial disc replacement with cutting posterior longitudinal ligament locally.@*RESULTS@#The indexes we calculated of the segments after the discectomy were statistically different compared with the intact segments (P0.05).@*CONCLUSION@#Artificial intervertebral disc replacement could keep the stability of the lumbar functional spine unit. There was no harmful effect of cutting posterior longitudinal ligament locally on the stability of lumbar while performing artificial intervertebral disc replacement when it is necessary.

Free dorsum flap lobule grafting for repair of third degree electric burn in two or three fingers / 中华显微外科杂志

Objective To report the therapeutic effect of free dursum flap lnbule grafting to repair soft tissue defects in two or three fingers result from electric bum in just one operation.Methods Seven patients with electric injuries in two or three fingers were treated by the dorsum flap (or composite flap) lohule graft- ing.The procedure is followed:after dehridement,a trifoliated flap composed of medial pedal,first dorsal met- atarsal and lateral pedal flaps or a bifoliated flap composed of first dorsal metatarsal and lateral pedal flaps was designed.The combined flap contained anterior tihial artery and dorsal pedal artery as the stem vessel for anas- tomosing with the supplying vessel.The three tributaries of dorsal pedal artery:medial tarsal artery,first dor- sal metatarsal artery and lateral tarsal artery were enntained in the three leaves respectively.They could contain extensor digitorum longus tendons and cutaneous nerves and be used to cover the skin defect of two or three fin- gers,reconstruct the flexor tendons and finger arteries and nerves at the same time.Results All the flaps were survived completely,the wounds in all fingers healed primarily,however,skin graft in two feet necrosised partly,one got to healing required wound dressing for three weeks,another required further operation of trans- ferring medial supramalleolar flap due to tendon exposure.The patients were followed up from 3 to 24 months, all the flaps were of appropriate thickness,good texture and satisfactory sensation,all the fingers recovered good function of flection and extension except two fingers existing little limitation.Conclusion Free dorsum flap lohule grafting is an ideal way to treat electric injuries of multiple fingers because it can recnnstruct the skin,tendons,blood vessels and nerves in two or three fingers in just one operation.

Microvascular anastomotic anterolateral thigh flaps for reconstruction of traumatic widespread defects of soft tissue in heel / 中华整形外科杂志

<p><b>OBJECTIVE</b>To explore the results of repairing widespread defects of traumatic soft tissue in heel by microvascular anastomotic anterolateral thigh flaps.</p><p><b>METHODS</b>Twenty-six consecutive free anterolateral thigh flaps in 26 patients were transplanted for repairing widespread defects of traumatic soft tissue in heel from October 1997 to March 2005, suturing the descending branch of the lateral circumflex femoral vascular and posterior tibial vascular to reconstruct the blood supply of transplanted flaps, repairing lateral femoral cutaneous nerve to recover their sensation, fixing tensor fasciae in the calcaneum to add their stabilization.</p><p><b>RESULTS</b>All flaps survived completely,the wounds healed in the initial treatment, follow up 3 to 48 months, twenty-six cases achieved partial sensation, good contour and stabilization.</p><p><b>CONCLUSIONS</b>The anterolateral thigh flap is an ideal flap for repairing widespread defects of traumatic soft tissue in heel, because it has such advantages as adequate blood supply, big dermatosis area and covert donor site, furthermore, nervi cutaneous femoris lateralis and tensor fasciae offer the good sensation and adequate stabilization.</p>