Spinal Cord Kinking in Thoracic Myelopathy Caused by Ossification of the Ligamentum Flavum / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Ossification of the ligamentum flavum (OLF) is being increasingly recognized as a cause of thoracic myelopathy. This study was to describe a rare clinical entity of spinal cord kinking (SK) in thoracic myelopathy secondary to OLF.</p><p><b>METHODS</b>The data of 95 patients with thoracic myelopathy secondary to OLF were analyzed retrospectively. The incidence and location of SK were determined using preoperative magnetic resonance imaging (MRI). The clinical presentation and radiological characteristics in patients with SK were analyzed. Posterior en bloc laminectomy with OLF was performed, and the surgical results were evaluated.</p><p><b>RESULTS</b>SK was found in seven patients (7.4%) based on preoperative MRI. The patients included one male and six females with an average age of 55.6 years (range, 48-64 years). Five patients presented with radiculomyelopathy and two presented with typical thoracic myelopathy of spastic paraparesis. In all cases, the kinking was located just above the end of the spinal cord where the conus medullaris (CM) was compressed by the OLF. The degree of SK varied from mild to severe. The tip of the CM was located between the upper third of T11 to the lower third of L1, above the lower edge of L1. With an average follow-up of 30.4 months, the modified Japanese Orthopedic Association score significantly improved from 5.7 ± 1.8 preoperatively to 8.9 ± 1.4 postoperatively (t = 12.05; P < 0.0001) with an improvement rate of 63.1 ± 12.3%.</p><p><b>CONCLUSIONS</b>SK is a rare radiological phenomenon. It is typically located at the thoracolumbar junction, where the CM is compressed by the OLF. Our findings indicate that these patients may benefit from a posterior decompressive procedure.</p>

A novel rabbit disc degeneration model induced by fibronectin fragment / 中华外科杂志

<p><b>OBJECTIVE</b>To establish a novel and useful rabbit model of lumbar disc degeneration using microinjection of fibronectin fragment (Fn-f).</p><p><b>METHODS</b>Thirty-two New Zealand white rabbits underwent injection of N-terminal 30 kDa Fn-f (experimental group) or phosphate buffered saline (PBS) (control group) into the central region of L1-2, L2-3, L3-4, L4-5 discs using a 32-gauge microsyringe. Two rabbits (blank group) with no treatments were sacrificed to examine the proteoglycan synthesis of neucleus pulposus (NP) using (35)S-sulfate incorporation assay. At the 4-, 8-, 12-, and 16-week time points, the discs were examined histologically, radiographically, and with proteoglycan synthesis.</p><p><b>RESULTS</b>Histology demonstrated a progressive loss of the cell numbers in NP and architecture destruction in NP and anulus fibrosus (AF) in Fn-f-injected discs over the 16-week study period. The NP regions in Fn-f-injected discs shrinked distinctly after the 4-week time point, and were not discernible with the inner AF by the 16-week time point. Protoglycan synthesis in Fn-f-injected discs decreased progressively (F = 263.241, P = 0.000). At each time point, the Fn-f-injected discs showed significantly decreased proteoglycan synthesis compared with controls (t = -27.010 - -2.833, P < 0.05). The DHI% of the Fn-f-injected discs at the 4-, 8-, 12-, and 16-week time points were 96.5% ± 1.7%, 85.6% ± 3.8%, 77.2% ± 3.5% and 65.5% ± 5.6%, respectively. Comparing with the DHI% of PBS-injected discs (97.4% ± 1.2%), the Fn-f-injected discs exihibited no significant differences in disc heights at the 4-week time point (P > 0.05), but significant decreases in disc heights at the 8-, 12-, and 16-week time points (t = -21.225 - -10.795, P < 0.01). Apparent anterior osteophytes formed at the 12-week time point and enlarged remarkablely by the 16-week time point in the experimental spines.</p><p><b>CONCLUSIONS</b>Fn-f can induce a progressively degenerative process in rabbit discs which is ethical, cost-effective, reproducible, and consistent with the spontaneous degeneration in human. And it seem to be a novel and useful model for the study of disc degeneration at the molecular level.</p>

The changes of extracellular matrix in adult degenerative nucleus pulposus cells with stiring microcarrier culture system in vitro / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the biological effect on the synthesis of the extracellular matrix (ECM) in the cultivation of adult degenerative nucleus pulposus cells using the stiring microcarrier system in vitro.</p><p><b>METHODS</b>Thirty-four specimens were collected after intervertebral fusion operations of the patients with intervertebral disc herniation diseases from September 2005 to May 2009. The specimens were then randomly allocated into 2 groups for in vitro cultivation: monolayer culture group and microcarrier culture group. On the exponential phase, SP-ABC immunohistochemical staining and Western blot quantitative analysis were conducted in the two groups to detect the collagen type I and II. Proteoglycan contents of two groups in different growth phases were detected with (35)S-sulfate incorporation assay.</p><p><b>RESULT</b>The expressions of collagen type I and II in microcarrier culture group were significantly higher than those in monolayer culture group: SP-ABC immunohistochemical staining (collagen type I: 32.5 ± 4.4 vs. 15.2 ± 1.2, t = 2.871, P < 0.01; collagen type II: 43.6 ± 4.1 vs. 23.1 ± 2.2, t = 2.375, P < 0.05); Western blot quantitative analysis (collagen type I: 0.62 ± 0.08 vs. 0.50 ± 0.06, t = 3.327, P < 0.01; collagen type II: 1.46 ± 0.08 vs. 0.86 ± 0.04, t = 2.453, P < 0.05). Nucleus pulposus cells cultivated in stiring microcarrier system showed significantly increased proteoglycan synthesis than monolayer culture group does on both exponential phase and stationary phase (exponential phase: 34 821 ± 312 vs. 21 046 ± 673, t = 2.134, P < 0.05; stationary phase: 45 134 ± 175 vs. 32 193 ± 713, t = 2.801, P < 0.01).</p><p><b>CONCLUSIONS</b>The expression of collagen type I, II and proteoglycan of adult degenerative nucleus pulposus cells are positive regulated by the stiring microcarrier system, which can be used in the mass amplification of the adult degenerative nucleus pulposus cells.</p>

A model of lumbar disc degeneration on the early stage in rhesus monkey with minimally invasive technique / 中华外科杂志

<p><b>OBJECTIVE</b>To establish a novel model of lumbar disc degeneration on the early stage in the rhesus monkey using percutaneous needle puncture guided by CT.</p><p><b>METHODS</b>(1) Thirteen rhesus monkeys aged from 4 to 7 years, female 7 and male 6 were selected for establishing a model of the early stage of lumbar disc degeneration. (2)13 monkeys, 91 discs were divided into 3 groups: 64 discs from L1/2 to L5/6 were percutaneous punctured with a needle 20G as experimental group and 1 disc with a needle 15G as puncture control group and 26 discs were not be punctured from L6,7 to L7-S1 as control group. (3) Lumbar disc localization for needle puncture was guided by CT. All discs were examined by MRI, the HE, Masson's trichrome, Safranine-O and immunohistochemical staining of type II collagen before disc puncture and after puncture at 4, 8 and 12 weeks.</p><p><b>RESULTS</b>MRI: (1) Experimental group: Pfirmann's Grade I was shown at postoperation 4, 8 and 12 weeks; (2) Puncture control group: Grade III was shown at postoperation 4 weeks and Grade IV at 8 weeks; (3) CONTROL GROUP: Grade I was shown at postoperation 4, 8 and 12 weeks. Histological examination: (1) In experimental group, there was no any change at postoperation 4 weeks, and the cell population of the nucleus was decreased at 8 weeks and more decreased at 12 weeks in HE. (2) There was no any change at postoperation 4 weeks, the clefts among the lamellae of the annulus fibrosus (AF) were shown at 8 weeks and more wider of the clefts of AF at 12 weeks in Masson's trichrome. (3) No any change was shown at postoperation 4 weeks, proteoglycan were progressively decreased at 8 and 12 weeks in Safranine-O. (4) No statistically significant difference in positive rate was observed at 4 and 8 weeks compared with control group in immunohistochemical staining of type II collagen. There was statistical difference at 12 weeks compared with control group (P<0.05). In puncture control group postoperation 8 weeks, the morphology of cell of nucleus pulposus was not clear in HE. The wider clefts of lamellae of the AF were shown in Masson's trichrome. The proteoglycan was obviously decreased in Safranine-O. Immunohistochemical staining collagen II synthesized was decreased. In normal control group, no any change was shown at 4, 8 and 12 weeks.</p><p><b>CONCLUSIONS</b>The degeneration of lumbar intervertebral disc on the early stage could be induced by the percutaneous needle puncture (20G) to the annulus fibrosus. The assessment of disc degeneration on early stage is not shown on MRI and only confirmed by histological examination.</p>

Constructing adeno-associated virus-TGFbeta3 and comparing its biological effect on proteoglycan synthesis in dedifferentiated nucleus pulpous cells with adenovirus-TGFbeta1 / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To construct adeno-associated virus (AAV) expression system for transforming growth factor beta3 (TGFbeta3 ) and detect its biological effect on proteoglycan synthesis of the earlier and later dedifferentiated rabbit lumbar disc nucleus pulpous (NP) cells, which was compared with that of adenovirus (AV) expression system for TGFbeta1.</p><p><b>METHODS</b>TGFbeta3 gene was obtained using PCR. Its upstream contained restriction enzyme site Kpn I, and its downstream contained restriction enzyme site Sal I. Using the restriction enzyme sites of PCR product of TGFbeta3 and the corresponding multiple cloning site (MCS) in plasmid AAV, TGFbeta3 was subcloned into AAV. The recombinant plasmid AAV-TGFbeta3 was transfected into H293 cells with Lipofectamine 2000, and the expression of TGFbeta3 gene was detected using immunofluorescent analysis. After AAV-TGFbeta3 virus particle with infectious activity was packaged, TGFbeta3 expression in NP cells was detected by immunoblotting, and its biological effect on proteoglycan synthesis was detected by antonopulos method and compared with that of AV-TGFbeta1 in the earlier and later dedifferentiated NP cells.</p><p><b>RESULTS</b>For the earlier dedifferentiated NP cells, AAV-TGFbeta3 slowly and stably enhanced proteoglycan synthesis, but AV-TGFbeta1 rapidly and transiently enhanced its synthesis. For the later dedifferentiated NP cells, AAV-TGFbeta3 stably enhanced proteoglycan synthesis, but AV-TGFbeta1 inhibited its synthesis.</p><p><b>CONCLUSION</b>AAV expression system can mediate TGFbeta3 gene to be expressed stably, and AAV-TGFbeta3 can enhance proteoglycan synthesis of the earlier and later dedifferentiated NP cells.</p>

Accuracy and related affecting factors of somatosensory evoked potential monitoring in cervical and thoracic surgery / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the accuracy and related affecting factors of the intra-operative somatosensory evoked potential monitoring in cervical and thoracic surgery.</p><p><b>METHODS</b>Cortical somatosensory evoked potential (CSEP) monitoring and sub cortical somatosensory evoked potential (Sub-CSEP) monitoring were performed in cervical and thoracic surgery. Somatosensory evoked potential (SEP) changes were recorded during anaesthesia and operation and postoperative, which could be used to evaluate accuracy of SEP.</p><p><b>RESULTS</b>Bilateral CSEP wave abnormalities were related to anaesthesia, decreasing wave amplitudes did not reach the alarming standard. Intra-operative manipulation to affect spinal cord would influence iso-lateral wave abnormality of CSEP and sub-CSEP, decreasing amplitudes reached the alarming standard. Local hypothermia such as cold water irrigating spinal cord would be to prolong the latent period. Low mean arterial pressure (MAP) mostly influenced amplitudes. Changes of SEP in local hypothermia and MAP did not reach the alarming standard.</p><p><b>CONCLUSIONS</b>CSEP and Sub CSEP can reflex physiopathological condition of spinal cord, it is useful in evaluating spinal cord function and providing the safety for cervical and thoracic surgery.</p>