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Biomedical subjects

L S Jia

Publications and source records attributed to L S Jia.

At least 19 recordsLinked to original sources
PubMed2005

Maximum entropy image deconvolution applied to structure determination for crystal Nd1.85Ce0.15CuO4-delta.

Eight [100] images from a through-focus series of tetragonal crystal Nd1.85Ce0.15CuO4-delta were transformed separately into the structure images by means of maximum entropy image deconvolution. The constructed projected structure model based on the deconvoluted image is confirmed by image simulation. It is demonstrated that the image deconvolution is still successful even when some reflections fall in the vicinity of zero cross of contrast transfer function. The effectiveness and advantages of the technique are discussed.

Journal Article↗
PubMed2004

Syntheses, thermal stability, and structure determination of the novel isostructural RBa3B9O18 (R = Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb).

A novel borate compound YBa(3)B(9)O(18) has crystallized in a melt of BaYB(9)O(16). Single-crystal X-ray diffraction measurements reveal that YBa(3)B(9)O(18) adopts a hexagonal space group P6(3)/m with cell parameters of a = 7.1761(6) A and c = 16.9657(6) A. The structure is made up of the planar B(3)O(6) groups parallel to each other along the (001) direction, regular YO(6) octahedra, and irregular BaO(6) and BaO(9) polyhedra to form an analogue structure of beta-BaB(2)O(4). A series of isostructural borate compounds RBa(3)B(9)O(18) (R = Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) were prepared by powder solid-state reactions. The DTA and TGA curves of YBaB(9)O(16) show an obvious weight loss at about 955 degrees C associated with a decomposition into YBO(3), B(2)O(3), and YBa(3)B(9)O(18) due to its incongruent melting behavior. The DTA and TGA curves of YBa(3)B(9)O(18) show that it is chemically stable and a congruent melting compound. A comparison of the structures of YBa(3)B(9)O(18) and beta-BaB(2)O(4) is presented.

Journal Article↗
PubMed2001

Direct repair of defect in lumbar spondylolysis and mild isthmic spondylolisthesis by bone grafting, with or without facet joint fusion.

Forty-six patients with lumbar spondylolysis and mild isthmic spondylolisthesis were managed with direct repair of the defect with or without facet joint fusion in the affected segment. There were 24 males and 22 females, ranging in age from 15 to 56 years (average, 38.2 years). These patients had experienced clinical symptoms due to spondylolysis for between 4 months and 20 years (average, 5.3 years). Of 46 patients, 28 had no spondylolisthesis, 11 had Meyerding grade I vertebral slippage and 7 had grade II. Direct repair of 98 defects was performed on these patients. Twenty-six patients, in whom the disc adjacent to the defect was determined as degenerative by magnetic resonance imaging (MRI), simultaneously underwent facet joint fusion; 17 in one segment and 9 in two segments. The average period of follow-up was 50 months (24-92 months). Ninety-four defects achieved bony healing. As a result, 28 patients were graded as having an excellent outcome, 15 good, and 3 fair. Bone grafting in the defects achieves union between the loose lamina and the anterior element of lumbar vertebrae, and reconstructs the anatomic structure and physiologic functions of the lumbar vertebrae. There was no significant difference in outcome between the spondylolytic/spondylolisthetic patients with non-degenerative disc, who were treated with direct repair of defect only, and those with degenerative disc, who additionally underwent a fusion procedure (P > 0.05). The present series demonstrates a satisfactory result and a high rate of bony healing of the pars defect by this operative procedure in patients with lumbar spondylolysis and mild isthmic spondylolisthesis. Preoperative assessment of the disc degeneration with MRI is of great assistance in making the protocol choice of whether to opt for fusion.

Adult↗
PubMed2000

Surgical treatment of nonunited fractures of the odontoid process, with special reference to occipitocervical fusion for unreducible atlantoaxial subluxation or instability.

Fifty-seven consecutive patients treated surgically for nonunited fractures of the odontoid process were reviewed. All patients presented late, exhibiting neurological deficits subsequent to nonunion. Delay in presentation was between 6 and 120 months (mean 32 months) after the original injury, due to missed diagnosis or inappropriate management. Seven patients who were reduced in traction underwent a Gallie atlantoaxial fusion. In the remaining 50 patients who were unreducible, an occipitocervical arthrodesis was performed. They were followed up for a minimum of 2 years, except one who died from postoperative respiratory failure. All patients obtained a solid bony union, including two in whom nonunion occurred following atlantoaxial fusion, and occipitocervical fusion was added as a rescue. Thirty-eight patients achieved excellent neurological recovery, nine still had some disability, five retained their neurological deficits and two reported a deterioration. In two patients, a recurrence in a traumatic episode was experienced long after a resolution. Our findings demonstrate that occipitocervical arthrodesis is preferable for unreducible subluxation or instability of atlantoaxial articulation in nonunion of odontoid fractures.

Adolescent↗
PubMed1996

Lumbar disc herniation in patients with developmental spinal stenosis.

Lumbar spinal stenosis and lumbar disc herniation are usually regarded as two pathogenetically different conditions, but in the literature lumbar disc herniation in patients with developmental spinal stenosis has been rarely documented. In a clinical retrospective study, 42 lumbar disc herniations with developmental spinal stenosis were reported and analyzed. Discectomy was performed after laminotomy. The patients were followed-up for an average of 4.4 years (range 2-7 years). The preoperative symptoms disappeared completely in 28 patients, in 13 patients some degree of backache remained although their nerve root pain had been relieved, and in 1 patient intermittent claudication reappeared after 6 years resolution of their preoperative pain. We conclude that when developmental spinal stenosis is combined with disc herniation, discectomy through laminotomy rather than laminectomy is usually sufficient for decompression.

Adult↗
PubMed1996

Multiple non-contiguous injuries of the spine.

Forty-seven patients with multiple non-contiguous injuries of the spine were reviewed retrospectively, giving an incidence of 5.4 per cent of 875 spinal injuries. Thirty-three were men and 14 women with an age range of between 16 and 78 years. Twenty-three were treated operatively. The multiple non-contiguous injuries had a more complicated mechanism of injury and tended to be more severe injuries than single-level injuries as they were combined more frequently with injuries of other parts of the body. Being aware of this combination of injuries leads to an earlier diagnosis. Operative reconstruction is recommended.

Adolescent↗
PubMed1994

Correlative study on findings of dynamic myelography and surgical operation in non-bony lumbar spinal canal stenosis.

The authors performed dynamic lumbar myelography with Omnipaque on 110 patients from 1990 to 1992, of them, 33 cases were diagnosed as non-bony lumbar spinal canal stenosis according to contrast medium defect seen on the lateral view of the myelogram. All such cases were operated on and their dynamic pathological findings during the operation were recorded to compare with the abnormal findings observed on the myelograms, there was a high coincidence rate of 88.7%. The authors believe that the fibrous degenerative changes make up the basis of dural sac compression and the dynamic compression in the spinal canal plays a very important role in causing the severity of the stenosis. As the dynamic pathological findings on the myelograms can not be well demonstrated on CT scanning and MR imaging, the dynamic lumbar myelography should be the method of choice for use in some cases.

Adult↗
PubMed1994

[Treatment of lumbar spinal stenosis with partial laminectomy and canal enlargement].

Thirty-eight patients with lumbar spinal stenosis were treated by partial laminectomy, incision of ligmental flava and canal enlargement. According to the pathological characteristic of lumbar spinal stenosis, both decompression and stability of the lumbar spine would be achieved by limited surgical treatment to the pathological segment and removing of any pathological factors. The average time for follow-up is 14 months. The excellent rate is 89.5%. The technique of the operation was also described and discussed.

Adult↗
PubMed1994

Radiographic measurement of the prevertebral soft tissue of cervical vertebrae.

The radiographic measurement of the prevertebral soft tissue of cervical vertebrae was performed in 87 normal adults. According to the results of the measurement, 10 mm and 20 mm were used as the upper limit normal values of the retropharyngeal and retrotracheal space respectively. We conclude that although the widened soft tissue space is of diagnostic significance, diagnosis should be made on the basis of analysis of the injury history, clinical manifestation and imaging examination.

Adult↗
PubMed1991

MRI and myelography in the diagnosis of lumbar canal stenosis and disc herniation. A comparative study.

We studied the diagnostic accuracy of magnetic resonance imaging (MRI) and the possibility of its substitution for myelography in 78 patients with lumbar canal stenosis and/or disc herniation, who had myelography and MRI examination. The diagnostic results of the two methods were compared respectively with those of operation, showing no statistical significance (coincidence rate 88.5% vs 92.3%, P greater than 0.05). We conclude that MRI could clearly reveal the pathological changes and anatomical relations of lumbar structures without invasive and radioactive damages, and that with the improvement of operative technique, better understanding of images, and reduction of cost, MRI is likely to replace myelography in the future.

Adult↗
PubMed1990

[Isthmic bone grafting in the treatment of lumbar spondylolysis].

Twenty-one patients with lumbar vertebral isthmic spondylolysis were treated by inserting bone graft in the isthmic defect. Grafting should also include the adjacent facet joints, thus after healing of grafted bone lumbar stability could be obtained, all cases were followed up for 10-15 months. Twenty-one patients had 44 isthmic lesions 39 of them revealed bony fusion radiologically (88.7%). On clinical evaluation, the combined excellent and good results reached 90.5%.

Adult↗
PubMed1990

Dynamic changes of the cervical ligamental flavum in hyperextension---hyperflexion movement and their measurements.

Ten fresh cadaver cervical spine specimens were frozen and bisected through the median sagittal plane. The length, thickness of the ligamental flavum (LF) and its protruding depth into the cervical canal were measured in hyperextension, hyperflexion and mid-position. The results showed that LF was elongated and became thinner in hyperflexion and shortened, thickened, and protruded into the cervical canal in hyperextension. The protruding depth into the canal was 3.5 +/- 0.35 mm at C 5-6, 3.25 +/- 0.50 mm at C 4-5 and 2.96 +/- 0.35 mm at C 6-7 respectively. Segmental stenosis was observed at the level of intervertebral space in hyperextension.

Adult↗
PubMed1989

[Dynamic change in the ligmenta flava of the cervical spine in motion].

Cervical spine specimen from fresh cadaver of 10 young persons, 8 males and 2 females, aged from 23 to 32 years, were divided right through the midline after frozen under -30 degrees C. Changes in length and thickness of each ligmenta flava were measured in hyperflexion and hyper extension as well as in neutral position. Being stretched long and thin in flex and contracted short and thick in extension, the ligmenta flava stuck into the spinal canal in position of hyperextension, mostly at C5-6 (3.50 +/- 0.34 mm) and then C4-5 (3.25 +/- 0.50 mm), C6-7 (2.96 +/- 0.61 mm) in descending order. This experiment definitely demonstrated that segmental narrowing of spinal canal , due to sticking in of ligmenta flava at each intravertebral level, was fashioned in hyperextension.

Adult↗
PubMed1989

[Preliminary report on the use of MRI in acute spinal trauma].

Forty three Magnetic Resonance (MR) studies were performed on 28 patients using a 1.5 Tesla magnet and surface coil. Imaging was performed between day 1 and day 16 after suspected cord injury. In several patients, repeat MR studies were performed to evaluate the resolution of the cord lesions. Three types of MR signal patterns were seen in association with the cord injuries. Patients with intraspinal hemorrhage did not have significant neurological recovery while patients with cord edema/contusion recovered significant neurological function. MR imaging would seem extremely useful in the diagnosis of acute cord injury and also appears to demonstrate the potential for predicting neurological recovery.

Acute Disease↗
PubMed1989

[Magnetic resonance imaging in the diagnosis of protrusion of a lumbar vertebral disc].

Signals of MR images which were done preoperatively on 86 patients with protrusion of lumbar vertebral disc were correlated to operative findings that were grouped, according to condition and position of the nucleus pulposus with relation to its annulus fibrosus, into 3 categories: protrusion, herniation and extrusion. Each of these 3 pathologic conditions was well-reflected on MRI image, a recognizable unique signal, characteristic of each category. Accordingly, the preoperative diagnosis in this series was 96.5% accurate, much better than that with any other methods; better still, MR imaging is non-invasive.

Adult↗
PubMed1989

[Lumbar discectomy and forominotomy].

17 patients, 11 males and 6 females, aged from 25 to 65 years (41.5 years, on average), suffered from lumbago and/or sciatica in various patterns, were operated upon. Lumbar discectomy and forominotomy were performed on 12 cases, and forominotomy only on 5. Follow-up of all the 17 patients found excellent and good results in 88.3% (15/17). Based on the experience from this small series of patients, we would suggest: forominotomy should be done on cases in whom neither disc protrusion nor yellow ligament thickening nor recess narrowing could be found, or the corresponding nerve root could not get free and still remain tight after discectomy, or the nerve root sustained tenderness on pressure when the operation was carried out under local anesthesia.

Adult↗