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Biomedical subjects

B Mahaisavariya

Publications and source records attributed to B Mahaisavariya.

At least 19 recordsLinked to original sources
PubMed2006

Finite element study of the proximal femur with retained trochanteric gamma nail and after removal of nail.

This study aims to evaluate the stress and strain distributions in the healed proximal femur after fixation with a trochanteric gamma nail (TGN) and after TGN removal, using the finite element method. The stress distributions in the proximal femur with retained TGN and after TGN removal were very similar. The strain and the strain energy density in the femoral neck region with retained TGN were much higher than in the lag screw hole at the subtrochanter and the distal locking screw hole at the proximal femur, and even higher after TGN removal. Stair climbing resulted in higher strain and higher strain energy density at the femoral neck than normal walking. The conclusion can be drawn that removal of the TGN may result in high risk of femoral neck fracture.

Bone Nails↗
PubMed2004

Morphology of the radial head: a reverse engineering based evaluation using three-dimensional anatomical data of radial bone.

The proximal part of the radius has a complex shape and dimension that cannot be precisely determined by standard roentgenogram for real three-dimensional anatomical shape which is important for prosthesis design. This study presents a method by which computer tomography (CT) images are combined with the reverse engineering technique to obtain and analyse the three-dimensional inner and outer geometry of the proximal radius. The three-dimensional models were reconstructed from CT images obtained from 40 radial bones and approximated with two- and three-dimensional fitting algorithms based on reverse engineering methods. The mean total length of the radius was 240.0 mm [standard deviation (SD) = 17.3]. The radial head in this study is more likely to be circular with an average diameter of 20.5 mm (SD = 1.9). The outer diameter of the radial neck averages 14.7 mm (SD = 1.0). The thickness of the radial head averages 12.9 mm (SD = 1.4). The intramedullary canal diameter of the radial neck averages 7.4 mm (SD = 1.4). The depth of the fossa at the articular surface averages 1.5 mm (SD = 0.4).

Adult↗
PubMed2003

Finite element study of trochanteric gamma nail for trochanteric fracture.

A three-dimensional finite element study of trochanteric fracture fixation by a trochanteric gamma nail (TGN) was investigated in this study. The analyses were performed under one-legged stance load boundary conditions to study the stress distribution and displacements. The influence of material properties (E-modulus) of the implant, the bone and contact condition in the fracture zone was determined. The results show that the stresses in the implant were lower in case of titanium alloy implant material but at the same time higher displacements occurred. The results also indicate that the stresses in the TGN gradually reduced throughout the healing process of the bone in the fracture zone.

Bone Nails↗
PubMed2001

Hemi-contralateral C7 transfer to median nerve in the treatment of root avulsion brachial plexus injury.

Because of the poor clinical results in achieving hand function in patients with complete brachial plexus root avulsion with other nerve transfers, we evaluated 111 patients prospectively to evaluate the technique of the hemi-contralateral C7 transfer to the median nerve. The transfer was performed as a primary procedure in 62 patients and as a secondary procedure in additional 49 patients. Twenty-one of the 62 patients in the primary group had sufficient follow-up (at least 3 years) to assess the motor and sensory recovery in the median nerve. The adverse effects of the operation were also analyzed in all 111 patients. Six of the 21 (29%) patients obtained M3 and 4 (19%) experienced M2 recovery of the wrist and finger flexors. Ten (48%) patients obtained S3 and 7 (33%) had S2 recovery in the median nerve area. The rate of the advancing Tinel's sign was markedly different between those achieving M3 function and the remaining patients. Although the age of the patient did not correlate with outcome, patients aged 18 and younger had the best motor recovery (ie, achieving M3 function in 3 of 6 cases). There was no correlation between the timing of the surgery after the initial injury, medical comorbidities, and clinical outcome. After surgery 108 of 111 (97%) patients experienced temporary paresthesia in the median nerve area, which resolved by an average of 2.8 months. Three (3%) patients had motor weakness of the donor limb; this resolved completely in 2 patients and left a mild deficit in wrist extension in 1 patient.

Adolescent↗
PubMed1996

Spinal accessory neurotization for restoration of elbow flexion in avulsion injuries of the brachial plexus.

Traumatic root avulsion brachial plexus injuries in 216 patients were treated with spinal accessory-musculocutaneous neurotization to restore elbow flexion. The average postoperative follow-up period was 6 years, with a minimum of 2 years for all patients. The percentage of satisfactory biceps recovery (MRC III or better) was 72.5%. The average interval between the operation and MRC III motor recovery was 17 months. The percentage of poor results increased from 25.5% to 62.5% in patients who underwent operation later than 9 months after injury. This method of neurotization produces a result comparable with, if not better than, the results of other types of neurotization in restoration of elbow flexion.

Accessory Nerve↗
PubMed1996

Osteotomy for cubitus varus: a simple technique in 10 children.

10 children with cubitus varus deformity after supracondylar fractures were operated on with a supracondylar lateral closing wedge osteotomy. The medial cortical periosteal hinge was left intact and the osteotomy stabilized with two Kirschner wires and a tension-band wire loop. The osteotomies healed within 2 months, without any complications or recurrence of the deformity. The outcome was satisfactory as regards both cosmesis and mobility.

Bone Wires↗
PubMed1995

Late open nailing for neglected femoral shaft fractures.

The results of open nailing in 14 cases of neglected closed femoral shaft fractures were reviewed. The mean patient's age was 28 years (range, 17-50). The mean delay to definitive treatment was 4.6 months (range 2-10). All fractures were malaligned with an average shortening of 4.9 cm (range 2.5-6.5). All cases underwent one-stage open nailing using the Küntscher nail fixation. The femur was shortened at the fractured end of one or both fragments to accomplish reduction in nine cases. The mean length of the bone resected was 9 mm (range 5-15). Only local callus was used for bone grafting in all cases. There were no neurovascular complications. All fractures healed an average of 3 months (range 2-4) after operation. Six cases had regained full knee flexion at the time of the latest follow up. Eight cases had decreased knee flexion with an average arc of knee flexion of 119 degrees (range, 100-125). The mean length of hospital stay was 7 days (range, 5-12). The method was found to be safe and effective with acceptable shortening and knee motion.

Adolescent↗
PubMed1995

Soft-tissue interposition of femoral fractures. Detection by ultrasonography during closed nailing.

We have compared the sonographic findings of six femoral fractures with soft-tissue interposition which required open reduction with those of a control group of 40 other femoral fractures. Ultrasound assessment before operation showed that the fractured end of the proximal fragment had penetrated the quadriceps muscle anteriorly while the distal fragment lay beneath it. Transverse scans showed less soft-tissue thickness over the end of the proximal fragment in the problem cases. Radiographic image intensification did not provide any additional information. Ultrasound is of value in demonstrating soft-tissue interposition at the fracture site before femoral nailing.

Adult↗
PubMed1995

Thumb reconstruction with a big toe microvascular wrap-around flap: a report of fifteen cases.

Fifteen thumb reconstructions were performed using the wrap-around procedure. A free wrap-around flap was taken from the big toe, and included the nail, and a part of the distal phalangeal skeleton. An iliac bone graft was added as the core of the reconstruction. One patient had an abnormal metatarsal arterial pattern which made the microsurgical reconstruction impossible, and another patient had early venous failure. Thirteen cases with successful thumb reconstruction were evaluated at an average of 27 months. Sensibility based on moving two-point discrimination ranged from 6 mm to 10 mm, and key pinch strength ranged from 0.5 kg to 3 kg. None of the patients had the problem of bone graft resorption, cold intolerance or social unacceptance after surgery. A postoperative study of the feet by Harris mat revealed an area of increased pressure under the second metatarsal head and the big toe stump. None of the patients experienced difficulty when walking or running on level ground.

Adolescent↗
PubMed1994

Charcoal bamboo as a bone substitute: an animal study.

UNLABELLED: Charcoal bamboo (Bambusae glaucescens) was placed in the resected tibial diaphysis of sixteen New Zealand White rabbits. At two, four and six weeks and again at six months after the operations, four rabbits in each period were killed and all specimens were examined under a light microscope and a scanning electron microscope. The six-week specimens showed that there was neobone invasion into the pores of the charcoal bamboo. There was no evidence of fibroencapsulation or inflammatory response. Due to its structure as a uniform porous material with interconnecting pores and carbon composition, the charcoal bamboo has been proved to be an osteotropic material. CLINICAL RELEVANCE: Charcoal bamboo should be an alternative bone substitute which may be used in humans in the near future. This material is available and easy to produce and prepare in developing countries.

Animals↗
PubMed1994

Rotational deformity of the distal humerus in cubitus varus.

The medial rotation deformity of the distal humerus usually exists in the cubitus varus deformity but has received little attention. Study of this deformity in 29 cases of cubitus varus was carried out using the osteotomized bony specimens that were removed during closed wedge osteotomy in order to determine the actual bone deformity. The average duration of the varus deformity was 5.6 yrs (range 1 to 11). The medial rotation deformity of the distal humerus averaged 27 degrees (range 15 to 45). There was no correlation between the degree of rotation and that of the varus deformity (correlation coefficient r = 0.15). The affected-side shoulder compensated well in both internal and external rotation, and had a greater arc of rotation than that of the normal side. The affected-side shoulder exhibited an internal rotation deformity with an average of 16 degrees (range 5 to 25), with restriction of external rotation of only 13 degrees (range 0 to 20) in comparison to normal side shoulder.

Adolescent↗
PubMed1994

Congenital pseudarthrosis of the tibia: treatment with free vascularized fibular graft.

Five children with congenital pseudarthrosis of the tibia were treated by resection of the lesion and reconstruction of the extremity with a free vascularized fibular graft (FVFG). Two of five cases had had multiple surgical procedures before FVFG. These two cases were complicated with the non-union of the proximal grafthost junction. Of these, one case achieved bone union after further resection of the non-union and adding allogenic bone graft and another case denied further operation and was lost to follow-up 6 months postoperatively. Three cases, two of which underwent FVFG as a primary treatment and another one after failure from the Sofield procedure respectively, were initially treated successfully and solid union of the grafthost junctions was within four months postoperatively. Problems including: anterior bowing, refracture, valgus deformity of the ankle and leg length discrepancy occurred in all four followed cases.

Adolescent↗
PubMed1994

Reconstruction of bone and skin defect using the osteocutaneous free fibular graft.

The attempt to use an osteocutaneous free fibular graft (OCFFG) to reconstruct composite bone and skin defects of the extremities following trauma was carried out in eighteen cases. Ten of seventeen cases were successful with the method without surgical complications and bony union occurred after 3 to 6 months (average 5.2 months). Three cases had skin flap necrosis (2 partial and 1 total) and required further skin grafting or skin coverage. Four cases failed due to thrombosis of the vascular anastomosis. The procedure was abandoned in one case because of failure to identify a reliable septocutaneous vessel to the skin flap.

Adolescent↗
PubMed1994

Iliotibial band for anterior cruciate ligament reconstruction: a new technique for graft augmentation, placement and fixation.

A simple surgical technique to reconstruct the ACL deficient knee was described. A strip of ITB and fascia lata augmented by degradable suture materials was used as the substitute. The strip was introduced into the isometric area of the original ACL attachment through a drill hole made in the lateral femoral condyle. Drilling was guided by the anatomical landmarks without using special device. The graft was then rigidly fixed to the tibia by intraosseous compression, the method previously described by the author. Clinical results were assessed by both subjective symptoms and physical examinations. In 33 patients followed-up for an average of 34.1 months, thirty of them who were chronic cases had few or no symptoms concerning pain, swelling, laxity and stiffness at the last visit. Lachman test, anterior drawer and Slocum test were negative in 87.92, 81.87 and 100 per cent respectively. This technique requires only basic instruments and skill, and is thus generalizable to institutions having limited surgical facilities.

Adolescent↗
PubMed1993

Supracondylar fracture of the humerus: malrotation versus cubitus varus deformity.

A study correlating the degree of medial rotational deformity of the distal humerus and the degree of cubitus varus deformity secondary to supracondylar fracture was performed in 23 patients who underwent corrective supracondylar osteotomy. The mean age of the patients at the time of operation was 10.9 years (range 5-14 years). The time interval from injury to operation averaged 3.2 years (range 1-6 years). A medial rotational deformity occurred in 20 cases. The degree of medial rotational deformity (MRD) averaged 16.2 degrees (range 0-34 degrees). Mean carrying angles (CA) of the deformed and normal sides were -19.6 degrees and 6.5 degrees, respectively. Mean humero-elbow-wrist (HEW) angles, measured from radiographs, of the deformed and normal sides, were -18.8 degrees and 7.7 degrees, respectively. There was no correlation between the degree of MRD and the degree of varus deformity, using as a comparison either the CA or the HEW angle of the deformed elbow or their differences from the normal side.

Adolescent↗
PubMed1993

Ultrasound or image intensifier for closed femoral nailing.

We describe a method of closed, unlocked nailing for femoral fractures using ultrasound instead of an image intensifier. Radiography was used only to confirm that the guide wire had been passed into the intramedullary canal of both fragments. The method succeeded in 26 of 30 cases. The failures all occurred in fractures which could not be reduced within 20 minutes. The operating time in those nailed successfully with ultrasound control was not different from the time for 30 control cases using conventional methods with an image intensifier.

Adolescent↗
PubMed1993

Ultrasonography of pulled elbow.

We used ultrasonography in ten children with pulled elbow to compare measurements of the radiocapitellar distance (RCD) on the affected and the unaffected sides. Similar measurements were made in a group of ten age-matched normal children. The mean RCD in pronation of the affected and normal sides in the patients with pulled elbows was 7.2 mm +/- 0.7 and 3.8 mm +/- 0.5, respectively (p < 0.0001). In the normal children the mean RCD in pronation was 4.5 mm +/- 0.5. We conclude that ultrasonography is of value for documenting pulled elbow in children.

Anthropometry↗