| Introduction:The traditional treatments for degenerative disc disease (DDD ) include conservative treatment (eg,medication, physical exercise and physics treatment) and surgery treatment (discectomy, intradiscal electrothermal therapy, spinal fusion at the affected level).For patients with persistent and disability,despite nonoperative therapy, surgical treatment was an effective method, it was confirmed that the surgical treatment (by extirpate the intervertebral disc nucleus and / or spinal fusion at the affected level) can relieve paint and maintain spinal column stable, but with the developing of the surgery of spinal column and the lucubrating research on construction of the intervertebral disc and biomechanics, more and more doctors were focus on spinal column biomechanics disorder and constructive abnormity caused by simply extirpate the intervertebral disc nucleus and / or spinal fusion at the affected level, as extirpating the intervertebral disc nucleus consequentially reduce of the heights of the intervertebral space, make the intervertebral space narrow, cause the corresponding piane stress of the front spinal column droping down, while the middle & back's increase, spinal column suffer abnormity movement or unstable, it may affect the long-term effects. Immobilization of the affected vertebrae and spinal fusion can solve the matter of intervertebral space becaming narrow and spinalcolumn unstable after operation, but it wasn't physiological, on the contrary, it may add the burthen of other vertebrae and make it degenerative, so it wasn't so good on correcting the front spinal column unbalance caused by DDD operation, the excellent and good rate of the operation was around 70%~85%, and around 3%~14% patients need second operation. So we believe that the spinal fusion wasn't the best treatment of degenerative disc disease.The best way for rebuild front spinal column require not only to rebuild a anatomic modality, but also need to rebuild function. Using intervertebral disc shaping— the PDN prosthetic disc-nucleus device replacement was one of the choices. The earliest PDN prosthetic disc-nucleus device replacement for intervertebral disc herniation was applied clinic in German (1996/01/26), until year 2002, there were around 550 patients who had accepted this treatment. In our country, the first PDN prosthetic disc-nucleus device replacement was applied in early 2002, as the difference between the Chinese and foreigners, most foreigners may use 2 PDN devices for one segment, while 1 PDN device was enough for Chinese. As it was a new guide worldwide developing and promising technology, though the case was limited, we were more concern if the single PDN prosthetic disc-nucleus device can recover the biomechanics balance of action segment after the operation, if the design of PDN device and the single PDN prosthetic disc-nucleus device can meet the requirement of Chinese intervertebral disc anatomic character, and how about the clinic effect of the PDN prosthetic disc-nucleus device replacement, and if it may cause any other potential complications.This report includes three part: the biomechanical test of single PDN prosthetic disc-nucleus device replacement; the anatomic research on the intervertebral disc and the clinic research of the PDN prosthetic disc-nucleus device replacement. Chapter one: the biomechanical test of single PDN prosthetic disc-nucleus devicereplacement Objectives:1. To evaluate the biomechanics affection of intervertebral disc moving segment after extirpating the intervertebral disc nucleus2. To evaluate the biomechanics affection of intervertebral disc moving segment after PDN prosthetic disc-nucleus device replacementMethods:Geting 6 fresh human adult lumbar spine(Ll ~S1) as specimen, before testing,do anteroposterior and lateral roentgenograms; By X-ray photos, we can get the heights and shapes of each specimen's lumbar 4-5 intervertebral gap, it can help for select the PDN prosthetic disc-nucleus device model to be used. Set each lumbar 4-5 intervertebrae as an action segment for testing, and do test in spinal column three-dimensional action test machine. The surgical procedure was laminotomy fenestration, a standard posterior right lateral approach was used to access the disc, check & record each specimen stability status when they were in normal condition (A section), postnucleotomy (B section) and after implanting PDN prosthetic disc-nucleus device (C section). Testing methods as: add 8N.M load when do flexion,extension, left lateral bending, right lateral bending, left axial rotation, right axial rotation direction moving in spinal column three-dimensional action test machine, collect photos by three-dimensional laser microscopical scanner, and we can get the range of motion(ROM)?. neutral zone(NZ) in different moving conditions by computer. One way NOVA and LSD method were adopted to Statistic and analyse the figuresResults: Comparing the extirpated intervertebral disc nucleus (B section) with normal condition (A section), the ROM of flexion, right / left axial rotation and NZ of flexion/extension, right / left axial rotation were increased, There was signifficantdifdifference(p<0.05), while the ROM and NZ of extension and left/ right lateral bending were almost same,there was no signifficant difdifference (P>0.05), these means after extirpated intervertebral disc nucleus, relevant vertebra's active stability drop down in flexion, right / left axial rotation direction moving; Comparing the PDN prosthetic disc-nucleus device (C section) with the extirpated intervertebral disc nucleus (B section), the ROM and NZ figures of all the direction moving were reduced, especially the figure for flexion, left axial rotation, right axial rorotation direction moving were obviously different(P<0.05); Comparing the PDN prosthetic disc-nucleus device (C section) with the normal condition (A section), the ROM and NZ figures were almost no obvious different on doing all direction action(P>0.05). This means with PDN prosthetic disc-nucleus device, it can recover the extirpated werea to normal condition.Conclusions: extirpating the intervertebral disc nucleus will cause the moving segmental biomechanics stability drop down, after implanting PDN prosthetic discnucleus device, lumbar intervertebral disc's biomechanics stability will recover to normal condition. PDN prosthetic disc-nucleus device satisfy the requirement of spinal column biomechanics. KEY WORDS lumbar intervertebral disc nucleotomy biomechanicsChapter two: measurement of lumbar intervertebral disc in normal adult and itsclinical significanceObjectives:1. Through anatomizing the normal adult's lumbar intervertebral disc to get Chinese person's intervertebral disc anatomic data2. To supply anatomic information for PDN prosthetic disc- nucleus replacement in China3. To supply anatomic data for PDN prosthetic disc-nucleus device designMethods:Geting 12 fresh adult lumbar spine as specimen, male 8, female 4, whose age were between 25 years and 60 years, no spinal column abnormality, bump and other serious degenerative disc disease.Normal anatomizing, horizontal cuting the second lumbar centrum to broken spinal column in central area, get lumbar and rumpbone, clear the lumbar soft tissue and anterior longitudinal ligament, horizontal cut vertebra base and saw off the posterior frame, clear posterior longitudinal ligament,so that to make the centrum bone part was different with the intervertebral disc up part and down part cartilage. Horizontally cut each lumbar and broken spinal column in central area, open intervertebral disc horizontally by cut its central point in the front and back with a thin and sharp knife, measure intervertebral disc's anteroposterior diameter (sagittal diameter) and transverse diameter (coronal diameter) in its transect middle part by vernier, intervertebral disc nucleus's anteroposterior diameter (sagittal diameter) and transverse diameter (coronal diameter) in middle part, the finitude between the annulus and nucleus was the complete annulus in the deepest part by eye, after collect all the figures, we can do a statistics .Results: the scope of 48 intervertebral disc nucleus's anteroposterior diameter (sagittal diameter) were 14.4mm ~25.4mm, all were bigger than 12 mm, and 5 of them were >24 mm ( 24 mm~25.4 mm), that was 10.4%; the scope of 48 intervertebral disc nucleus's ransverse diameter (coronal diameter) were over 25mm (27.9mm ~37.6 mm);the scope of 48 intervertebral disc's sagittal diameter in middle part were 24.6mm ~~ 39.2mm, and 19 of them were >37 mm, that was 39.6%; While there were 14 specimen in thwas 19 specimen which intervertebral disc nucleus's sagittal diameter were less than 24 mm. that was 73.7%; Intervertebral disc 's ransverse diameter scopewere 39.7mm ~56.5mm. Conclusions:1. Chinese only need single PDN prosthetic disc-nucleus device in one segment as its character.2. It was necessary to design several kinds of PDN-SOLO or PDN-SOLOXL which was different in tansverse diameter on developing PDN prosthetic disc-nucleus device, it was help for preventing the device from intervertebral disc shifting or extrusion; The height specification above 9 mm PDN device design will be useful.3. Currently, the single PDN prosthetic disc-nucleus device treatment was more suitable for Chinese.KEYWORDS Intervertebral disc Anatomizing prosthetic PDNChapter three: the clinical research on the PDN prosthetic disc-nucleus devicereplacement for intervertebral disc herniationObjectives:1. To evaluate clinical curative effect of the PDN prosthetic disc-nucleus device replacement2. To evaluate the ability of PDN prosthetic disc-nucleus device in recovering and preserving the height of the intervertebral gap3. To evaluate if the PDN prosthetic disc-nucleus device replacementt will cause some complications, and discuss the pathogeny and preventative action for the complications.Methods: There were 53 cases of intervertebral disc herniation who were applied with the PDN prosthetic disc-nucleus device replacement from Mar. 2002 to Nov. 2004, 32 were male and 21 female; 20 cases were on lumbar 5 rumpbone 1 gap,28 cases were on lumbar 4-5 gaps, 3 cases were on lumbar 3-4, 1 case was on lumbar 3-4 gap and lumbar 4-5 gap, 1 case was on lumbar 2-3 gap and lumbar 4-5 gap. Clinical information: pain in wawast and back werea, it may have radiate pain to legs. It was confirmed that all patients were caused by intervertebral disc herniation by CT or MRI. Applied the operations and standard posterior approach of extirpated intervertebral disc nucleus, select certain PDN prosthetic disc-nucleus device with the reference of X-radiate photos in lumbar lateral area, and each section implanted 1 PDN device. Follow-up regularity after operation, observed the curative effect and caused complications, the following-up schedule set as 3 months after operation, 6 months, 12 months, 18 months, 24 months, 30 months, 36 months, and so on Before operation and each following-up, it must ask the interviewee to fulfill Oswestry Disability Index questionnaire (ODI) and Prolo functional and Disability Scale, evaluated the clinical curative effect with the interview result. Take X-radiate in intervertebral disc anteroposterior and lateral area before operation, 7 days after operation and on each following-up, or even have a CT or MRI if possible, by this way to clear the position of PDN prosthetic disc-nucleus device and to find out if it shift or extrude, if the intervertebral disc moving endplate dent, measure the vertebra gap after operation.Results: Around 51 case in the 53 ( 96.23% ) were accept interviewing,following-up time from 3 months ~ 3 years, average 22.7 months.The mean preoperative Oswestry score was 54.8%.the score did improve to 24.5% at the 3-month follow-up, 19.8%at the 6-month follow-up, 11.8% at the 12-month follow-up, 10.8% at the 18-month follow-up, 8.8% at the 24-month follow-up, 7% at the 30-month follow-up and 5% at the 36-month follow-up. Oswestry score showed significant improvement. The mean preoperative Prolo score was 5.6,it improved to 7.2 at the 3-month follow-up, 8.5 at the 6-month follow-up, 9 at the 12-monthfollow-up, 9.5 at the 18-month follow-up, 9.8 at the 24-month follow-up, 10 at the 30-month follow-up, and 10 at the 36-month follow-up. Prolo score showed significant improvement.The mean preoperative disc height was 7.9mm,it increased to 9.8mm at 7 days after operation, 9.9mm at the 3-month follow-up,the mean disc height was 9.8mm, 9.7mm, 9.6mm, 9.4mm, 9.3mm, 9.4mm at the 6-month, 12-month, 18-month 24-month, 30-month, 36-month follow-up respectively.lt showed that the PDN device could restore and maintain disc height.The following complications were found in the 51 interviewees: the PDN prosthetic disc- nucleus device extrusion in 4 patients; intervertebral disc inflammation inl patient; endplate denting in 1 patient; transient pain aggravation in 7 patients and the PDN prosthetic disc-nucleus device shifting in the intervertebral disc in 3 patients.All the patients were cured. The second operation were done for the four patients whose implant extruded: the PDN prosthetic disc-nucleus device was took out for 2 patient; the former device was took out and re-implanted a bigger one for 1 patient; the device was took out and did intervertebral fusion operation with two Cage for 1 patient.The patient whose disc inflammation was cured by taking orally diminishing inflammation medication& anodyne, laying up for rest, 6 months later intervertebral space fusion appeared , no uncomfortable feeling.The patient whose endplate dented had no special uncomfortable, just needed being kept checking. The 7 patients who had transient pain aggravation were cured by taking orally diminishing inflammation medication& anodyne, laying up for rest,and recoved after 3~10 days . The 3 patients whose device shift in the intervertebral disc had no special uncomfortablejust needed being kept checking. Conclusions:The PDN prosthetic disc-nucleus device replacement is a new technology in curing intervertebral disc herniation disease; it can recover and keep the height of the vertebra gap after extirpated its intervertebral disc nucleus, and it can also maintenance the moving section activity, From currently curative effect, it was in good condition, it was a developing direction of the spinal column surgery, but as a new technology, new products, it also have some problems, such as device extrusion, endplate denting, it require clinic doctor to improve operation skill, strictly control operation indication and contraindication, and engineers and technicians need to do more research on the design of the device; We also need to do a research on its medium-term and long-term observation.
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