| At present, cervical artificial disc replacement has been widely used in the surgical treatment of cervical spondylosis, it can achieve complete decompression of the spinal canal and relieve symptoms, retaining the physiological cervical motor function, thus avoiding adjacent segment degeneration due to compensatory overactivity after interbody fusion. Artificial cervical disc replacement surgery has become one of the hot spots in the field of spine surgeryBecause the technical threshold is high due to the research and development of artificial cervical disc, there is not yet any domestic cervical artificial disc into the market, the domestic market is occupied by foreign brands. There are some shortcomings for foreign products:first of all, foreign products are expensive, increasing the patients’economic burden; secondly, foreign products are different in sizes and biomechanics with Asian, because the foreign products are designed based on the European and American ethnic anatomical parameters; in addition, indications for surgery also refer to foreigners, we still did not have our own independent and comprehensive standards. In this situation, our hospital combined with the Shenzhen Research Institute of Tsinghua University institutions designed new home-made cervical disc prosthesis, consistent with the physiological size characteristics of Chinese. New home-made cervical disc prosthesis used the fixed nucleus pulposus ball-groove joint design, inferior endplate material titanium alloy (Ti6A14V), the nucleus pulposus material for ultra-high molecular weight polyethylene (UHMWPE).Because goats have similar anatomical parameters and biomechanical characteristics with human, it can be served as an optimal model for cervical research. We establ ish home-made cervical artificial disc goat model to s imulate the human cervical spine surgery, in order to assess the feasibility of domestic cervical artificial disc implant surgery, so as to provide an experimental basis for further clinical applications.1ObjectiveThe purpose of this study was to establish an animal model for new home-made cervical disc prosthesis, observe cervical activity, stability and adjacent segment degeneration after implantation, and evaluate the safety and effectiveness of home-made cervical artificial disc, in order to provide a theoretical basis for the prosthesis further exper i mental study, so as to provide an experimental basis for further clinical applications.2Methods2.1In this part of study, a new type of home-made cervical disc prosthesis was designed and made, based on the goat cervical anatomical parameters.2.2Establishing an animal model for new home-made cervical disc prosthesis, evaluating the operation time, blood loss, postoperative recovery time of act ivi ty.2.3Experimental goats were randomly divided into3groups:CDR group coated with hydroxyapatite, CDR group uncoated with hydroxyapatite, and autologous iliac group, neck3/4plate were removed in3groups, replaced respectively by home-made cervical disc prosthesis and autologous iliac. Observed by imaging (cervical X-ray film), indicators include:(1) disc space height (DSH) intervertebral angle (IVA) and lordosis angle (LA);(2)the ROM of C2-C5;(3)the ROM of C3/4;(4)to assess the situation of adjacent segment degeneration by kellgren score;(5)measurement of relative disc height;(6)histological observation.Experimental groups were divided into post-operation1month and post-operation3months, and respective control group is designed. The above measurement indicators were expressed as mean+standard deviation (x±s), and analyzed with SPSS16.0statistical package.3Results3.1A new type of home-made cervical disc prosthesis has been designed and made.3.2All experiment goats survived after operation, without incision infection and paralys is, the average blood loss was3.6±0.5ml, the average operation time was80±6min, the average time of resuming activities after operation was4.5±1.2h.3.3(l)Statistical comparison showed no significant difference of DSH, IVA and LA preoperatively and postoperatively immediately between the CDR group coated with hydroxyapatite, CDR group uncoated with hydroxyapatite and control group. There was no significant difference with respect to DSH, IVA and LA in coated disc group postoperatively immediately,1month postoperatively and3months postoperatively (p>0.05); While at1and3months postoperatively, significant difference existed in uncoated disc group and coated disc group, control group (p<0.05). There was no significant difference between coated disc group and control group (p>0.05).(2)There was no significant difference with respect to ROM in coated disc group postoperatively immediately,l month and3months postoperatively (p>0.05); While there was significant difference with respect to ROM in uncoated disc group postoperatively immediately,l month and3months postoperatively (p<0.05); At1and3months postoperatively, significant difference existed in uncoated disc group and coated disc group, control group (p<0.05). There was no significant difference between coated disc group and control group (p>0.05).(3)There was no significant difference with respect to the ROM of C3/4in coated disc group postoperat ively immediately,1month and3months postoperat ively (p>0.05); While there was significant difference with respect to ROM of C3/4in uncoated disc group postoperatively immediately,1month and3months postoperatively (p<0.05) At1and3months postoperatively, significant difference existed in uncoated disc group and coated disc group, control group. There was no significant difference between coated disc group and control group (p>0.05).(4)Kellgren score results:there was no significant difference between the CDR group and control group. At1and3months postoperatively, significant difference existed in CDR group and autologous iliac group (p<0.05), there was no significant difference with respect to score between C2/3gap and C3/4gap (p>0.05)(5)There was no significant difference with respect to RDH among CDR group, autologous iliac group and control group preoperatively (p>0.05); There was no significant difference with respect to RDH in CDR group postoperatively immediately,1month postoperatively and3months postoperatively (p>0.05); While there was significant difference with respect to RDH in autologous iliac group postoperatively immediately,1month postoperatively and3months postoperatively (p<0.05); At1and3months postoperatively, significant difference existed in autologous i l iac group and CDR group, control group. There was no significant difference between CDR group and control group (p>0.05)(6) At3months postoperatively, in CDR group and control group, nucleus pulposus had a large quantity of extracellular matrix, and some fine collagen fibrils sparsely arranged among the matrix. A few chondrocyte-like cells dotted in them. While in autologous iliac group, extracellular matrix decreased, but collagen fibrils began larger and thicker and more irregularly arranged among the matrix. The number of viable cells decreased, and necrotic cells increased.4ConclusionNew home-made artificial cervical disc system is easy to operate, has less blood loss, shorter operative time, less complications and early recovery of movement, and can maintain the stability of the cervical spine and retain the activity of the cervical spine, what’s more,can prevent adjacent segment degeneration accelerating. Preliminary evidence confirmed the prosthesis may yield good functional short-term results, further follow-up is necessary to evaluate mid-and long-term outcome in vivo applications. |
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