Comparison of two temporary fixation techniques for the treatment of type II odontoid fracture.

To evaluate and compare the clinical and radiographic results between temporary C1-C2 pedicle screw fixation and cable-dragged reduction and cantilever beam internal fixation. Between 2010 and 2013, temporary C1-C2 pedicle screw fixation (Group P, 28 patients) and cable-dragged reduction following cantilever beam internal fixation (Group C, 33 patients) were performed on type II odontoid fracture cases. Implants were removed after fracture union. All of the 61 surgeries were performed successfully with no iatrogenic neurological worsen. One patient in Group P detected intra-operative vertebral artery injury. All patients gained fracture union. Among the observed indexes, only blood loss in Group P (128.9 ± 73.9ml) is statistically higher than in Group C (97.3 ± 5 4.2ml). Pedicle screw fixation carries the risk of vertebral artery injury, especially in patients with high-riding vertebral artery. Cable-dragged reduction following cantilever beam internal fixation could avoid the potential risk of vertebral injury, but it prolonged the fixed segments. We thought cable-dragged reduction following cantilever beam internal fixation could be an alternative method for treating type II odontoid fracture.

A mediator-free glucose biosensor based on glucose oxidase/chitosan/α-zirconium phosphate ternary biocomposite.

A novel glucose oxidase/chitosan/α-zirconium phosphate (GOD/chitosan/α-ZrP) ternary biocomposite was prepared by co-intercalating glucose oxidase (GOD) and chitosan into the interlayers of α-zirconium phosphate (α-ZrP) via a delamination-reassembly procedure. The results of X-ray diffraction, infrared spectroscopy, circular dichroism, and ultraviolet spectrum characterizations indicated not only the layered and hybrid structure of the GOD/chitosan/α-ZrP ternary biocomposite but also the recovered activity of the intercalated GOD improved by the co-intercalated chitosan. By depositing the GOD/chitosan/α-ZrP biocomposite film onto a glassy carbon electrode, the direct electrochemistry of the intercalated GOD was achieved with a fast electron transfer rate constant, k(s), of 7.48±3.52 s(-1). Moreover, this GOD/chitosan/α-ZrP biocomposite modified electrode exhibited a sensitive response to glucose in the linear range of 0.25-8.0 mM (R=0.9994, n=14), with a determination limit of 0.076 mM.

Comparison of Long-Term Outcomes between the n-HA/PA66 Cage and the PEEK Cage Used in Transforaminal Lumbar Interbody Fusion for Lumbar Degenerative Disease: A Matched-Pair Case Control Study.

OBJECTIVE: The nanohydroxyapatite/polyamide-66 (n-HA/PA66) cage is a novel bioactive nonmetal cage that is now used in some medical centers, while the polyetheretherketone (PEEK) cage is a typical device that has been widely used for decades with excellent clinical outcomes. This study was performed to compare the long-term radiographic and clinical outcomes of these two different cages used in transforaminal lumbar interbody fusion (TLIF). METHODS: In this retrospective and matched-pair case control study, we included 200 patients who underwent TLIF from January 2010 to December 2014 with a minimum 7-year follow-up. One hundred patients who used n-HA/PA66 cages were matched with 100 patients who used PEEK cages for age, sex, diagnosis, and fusion level. The independent student's t-test and Pearson's chi-square test were used to compare the two groups regarding radiographic (fusion status, cage subsidence rate, segmental angle [SA], and interbody space height [IH]) and clinical (Oswestry Disability Index [ODI], and Visual Analog Scale [VAS] for back and leg) parameters preoperatively, postoperatively, and at the final follow-up. RESULTS: The n-HA/PA66 and PEEK groups had similar fusion rates of bone inside and outside the cage at the final follow-up (95.3% vs 91.8%, p = 0.181, 92.4% vs 90.1%, p = 0.435). The cage union ratios exposed to the upper and lower endplates of the n-HA/PA66 group were significantly larger than those of the PEEK group (p < 0.05). The respective cage subsidence rates in the n-HA/PA66 and PEEK groups were 10.5% and 17.5% (p = 0.059). There were no significant differences between the two groups in the SA, IH, ODI scores, or VAS scores at any time point. The n-HA/PA66 group showed high fusion and low subsidence rates during long-term follow-up. CONCLUSION: Both n-HA/PA66 and PEEK cages can achieve satisfactory long-term clinical and radiographic outcomes in TLIF. However, the n-HA/PA66 group showed significantly larger cage union ratios than the PEEK group. Therefore, the results indicated that the n-HA/PA66 cage is an ideal alternative material comparable to the PEEK cage in TLIF.

Polyphenolic-modified cellulose acetate membrane for bone regeneration through immunomodulation.

To enhance the bioactivity of cellulosic derivatives has become an important strategy to promote their value for clinical applications. Herein, protocatechualdehyde (PCA), a polyphenolic molecule, was used to modify a cellulose acetate (CA) membrane by combining with metal ions to confer an immunomodulatory activity. The PCA-modified CA membrane has shown a significant radical scavenging activity, thereby suppressed the inflammatory response and created a favorable immune microenvironment for osteogenesis and mineralization. Moreover, addition of metal ions could further stimulate the osteogenic differentiation of stem cells and accelerate bone regeneration both in vitro and in vivo. This study may provide a strategy to promote the immunomodulatory activity of cellulose-based biomaterials for bone regeneration.

[Application of n-HA/PA66 composite artificial vertebral body in anterior reconstruction of lower cervical spine fracture and dislocation].

OBJECTIVE: To initially evaluate the application of artificial vertebra of n-HA/PA66 in anterior reconstruction of lower cervical spine fracture and dislocation. METHODS: In this study, 84 patients with lower cervical spine fracture and dislocation received anterior cervical discectomy, spinal canal decompression or subtotal corpectomy, spinal canal decompression and reconstruction by n-HA/PA66 composite artificial vertebral body combined with plate instrumentation. Neurological function was followed up by improvement rate of Frankel and situations of the supporting body was observed by X ray and 3D-CT in 3, 12, 24 months postoperatively. The intervertebral height, physical arc (reflected by Cobb angle) and the locations and fusion rate of the supporting body were assessed in order to evaluate the stability of the cervical spine and alignment improvements. RESULTS: All the patients underwent operation successfully and were followed up for 6 to 24 months with an average of 12 months. The preoperative symptoms were improved to varying degrees. Imaging studies showed that in all cases graft fusion were achieved, and cervical alignments, intervertebral height, cervical spine stability and the locations of the artificial vertebral body were well maintained. No displacement and subsidence of the artificial vertebral body occurred. Postoperative immediate intervertebral height (2.4 ± 0.2) cm, preoperative intervertebral height (1.9 ± 0.1) cm, comparisons of the two groups was statistically significant (q = 2.48, P < 0.001). The immediate, 3 month, 1 year, 2 year period follow-up group intervertebral height was not statistically significant (P > 0.05). Preoperative Cobb angle was 9.8° ± 1.2°, postoperative immediate Cobb angle was 16.6° ± 1.2°, comparisons of the two groups was statistically significant (q = 14.25, P < 0.001). The immediate, 3 month, 1 year, 2 year period follow-up group Cobb angle was not statistically significant (P > 0.05). CONCLUSIONS: n-HA/PA66 artificial vertebral body can provide early cervical spine support and stability and effectively maintain the biological alignment and cervical intervertebral height. It has high rate of graft fusion and is convenient to observe by X-ray. Therefore, n-HA/PA66 can be taken as an ideal graft for anterior lower cervical spine fracture and dislocation operation, but further follow-up study is still required to evaluate the long-term effects.

Novel biodegradable α-TCP/poly(amino acid) composite artificial lamina following spinal surgery for prevention of intraspinal scar adhesion.

Biodegradable copolymer α-TCP/poly(amino acid) composite artificial lamina was prepared and used in goat cervical vertebra resection repair. Cervical 4 was removed by laminectomy, and a vertebra defect of 27 × 9 mm was made. α-TCP/poly(amino acid) composite artificial lamina was inserted in the test group. The efficiency of the copolymer during repair and reconstruction of the goats' vertebra was tested by using X-ray, CT scanning, and histological and biomechanical measurements. In the 24 weeks following the operation, the artificial lamina refrained from shifting, and no dural adhesion pressure was observed. In contrast, the control group suffered from infiltration of soft tissue in the spinal canal, dural pressure and α-TCP/poly(amino acid) degradation. In conclusion, α-TCP/poly(amino acid) composite artificial lamina can significantly prevent scar tissue from infiltrating the spinal canal.

Sutureless fixation of amniotic membrane patch as a therapeutic contact lens by using a polymethyl methacrylate ring and fibrin sealant in a rabbit model.

PURPOSE: To introduce and evaluate a sutureless technique by using a polymethyl methacrylate (PMMA) ring and fibrin sealant to fix an amniotic membrane (AM) patch on the ocular surface as a therapeutic contact lens in a rabbit model. METHODS: PMMA rings were fabricated by duplicating an impression of a rabbit conjunctival fornix. The central cornea of the left eye in 16 rabbits was deepithelialized (diameter = 10 mm). A human AM patch was fixed to the ocular surface by using either a PMMA ring and fibrin sealant or interrupted 10-0 nylon sutures. The fibrin sealant was used to create the PMMA ring-AM complex but not to attach the AM/PMMA ring to the ocular surface. The rabbits were followed up with slit-lamp examination and fluorescein staining for 7 days. Reepithelialization and complications were recorded. RESULTS: The corneal epithelial defect was recovered in each rabbit of both groups after 5 days. In the sutureless group, all membranes remained in place and intact during the follow-up period. One eye was noted to have a partial conjunctival epithelial defect caused by exposure to the PMMA ring. In contrast, >50% of rabbits in the interrupted suture group exhibited complications including conjunctival edema, suture loosening, patch detachment, bleeding, and conjunctival epithelial defects. CONCLUSIONS: The sutureless technique that uses a PMMA ring and fibrin sealant for AM patch placement has a lower incidence of complications than the interrupted suture method. This sutureless technique may promote increased clinical use of AM patch by alleviating patients' pain and shortening surgical time.

Effect of polylactic acid glue in preventing epidural scar adhesion after laminectomy in rabbits.

OBJECTIVE: To determine the efficacy of polylactic acid glue in preventing epidural scar adhesion after laminectomy in rabbits. METHODS: Twenty-four Japanese white rabbits underwent laminectomy (including the attached ligaments) at L(2 ) and L(5). After laminectomy at L(5), polylactic acid glue was sprayed on the dura and nerve roots and this segment was taken as the experimental group. After laminectomy at L(2), nothing was used and this segment was enrolled as the self control group. Four rabbits were killed every two weeks postoperatively till the end of the experiment at 12 weeks. Then the operated spine was observed grossly, histologically and ultrastructurally to check the degree of scar formation, the status of epidural scar adhesion, the absorption of the glue, and the intracellular structure of fibroblasts. RESULTS: The glue coagulated immediately after spraying and showed excellent hemostatic effect. The glue membrane was easy to be taken away from the dura mater of the samples for 2 weeks and there were no cells in the epidural space in the experimental group. But the dura mater was covered by hematoma in the control group, which formed mild adhesion, with fibroblasts proliferating actively. In the 4th week, some glue shivers remained in the epidural space with fibroblasts increasing a little, and the dura mater was smooth in the experimental group. However, in the control group, the formed scar was fragile and conglutinated with the dura mater diffusely and fibroblasts were much more than those in the experimental group. In the 6th-12th weeks, there was a potential interspace between the scar and the dura mater, and the polylactic acid glue was absorbed completely in the experimental group. Much tough scar was found in the control group, which was very difficult to dissect from the dura mater and the surrounding tissues. From the ultrastructural observation of the fibroblasts, the nucleus became much bigger and the rough endoplasmic reticulum was much more plentiful in the control group than that in the experimental group. CONCLUSIONS: Polylactic acid glue can effectively reduce epidural cicatrization and adhesion.

[Treatment of chronic apical periodontitis teeth complicated by open apices with Vitapex in the adults].

PURPOSE: The aim of this study was to evaluate Vitapex (a premixed calcium hydroxide and iodoform paste) for treatment of chronic apical periodontitis complicated by incompletely developed apices in the adults. METHODS: 36 teeth with incompletely formed apices were selected. After the root canals were prepared and sterilized , Vitapex was used in the apexification. All the patients were followed-up clinically and radiographically 3 months and 10-18 months postoperatively. The root canal were then filled with Obtura II gutta-percha when the apical barrier could be detected. RESULTS: A radiographic evaluation showed that 7(19.4%) teeth completed root development and apical closure. 27 (75%) teeth could be detected apical barrier. 2 (5.6%) teeth were failed. The overall success rate was 94.4%. The average period of the whole endodontic treatment was 13.0 weeks. CONCLUSION: Vitapex is a good material in the treatment of chronic apical periodontitis complicated by incompletely formed apices in the adults.

[Evaluation of sealing ability of three kinds endodontic materials as root canal sealers].

OBJECTIVE: To compare the apical microleakage of Vitapex (calcium hydroxide based paste) with that of AH-plus and zinc oxide eugenol sealer when used with laterally condensed gutta percha obturation technique. METHODS: One hundred single rooted human anterior teeth were instrumented and randomly divided into three experimental groups (A, B, C) of 30 teeth each and two control groups (D, E) of 5 teeth each. Group A was filled with laterally condensed gutta-percha using Vitapex as sealer. Group B was filled with laterally condensed gutta-percha using AH-plus as sealer. Group C was filled with laterally condensed gutta-percha using zinc oxide eugenol as sealer. Group D was the positive control. Group E was the negative control, which were coated with nail polish to entire root surface. Teeth were then suspended in 2% methylene blue. After this, teeth were demineralized dehydrated and cleared. Linear dye penetration was determined under stereomicroscope with calibrated eye piece. RESULTS: The mean dye penetration for group A, B, C were respectively (0.57 +/- 0.56) mm, (0.79 +/- 0.96) mm and (1.07 +/- 1.12) mm. Group D demonstrated maximum dye penetration. Group E showed no dye penetration. There was no statistically significant difference between group B and group C (P > 0.05). However, there was statistically significant difference between group A and group B, C (P < 0.01). CONCLUSION: This study showed that Vitapex used as endodontic sealer material are better than AH-plus sealer and zinc oxide eugenol sealer.

[Clinical study of prevention of epidural scar and adhesion with polylactic acid membrane].

OBJECTIVE: To investigate the clinical effect of polylactic acid membrane in prevention of epidural scar and adhesion. METHODS: From July 1998 to April 2000, 62 patients with lumbar disc herniation were randomly assigned into two groups. All were treated surgically with discectomy by fenestration or laminectomy. One group were placed with a thin of polylactic acid membrane covering the interlaminar space(n = 32). The thickness of the film was 0.1 mm. The other group was blank control(n = 30). After 2 weeks of operation, we observed the local and systemic reactions. After 6 months clinical symptoms were revaluated and the degrees of epidural scar and adhesion were determined by CT scans. RESULTS: After 2 weeks, we found no adverse systemic reactions in all patients. Wound healing was excellent. No abnormalities of hepatic and renal functions as well as blood for routine were found. Temperature after operation was normal. After 6 months, the curative effects were as follows in experimental group and in control group: excellent in 27 patients and in 24 patients, good in 4 patients and in 4 patients, fair in 1 patient and in 1 patient, and poor in 0 patient and in 1 patient, respectively. There are no significant difference between two groups. The CT scans showed no adhesion between the epidural scar and the dural sac in all patients of experimental group. There existed various extents of adhesion in control group. CONCLUSION: The results demonstrate that the polylactic acid membrane can effectively prevent the epidural scar adhesion with a good biocompatibility and no toxity. Its clinical application was promising.