ABSTRACT: Hydroxyapatite (HA) is considered to be useful because of its high affinity for recombinant human bone morphogenetic protein (rhBMP), mechanical resistance to compressive force, and possible reduction of rhBMP dose.
To evaluate the osteoinductivity of Escherichia coli-derived rhBMP-2 and the suitability of porous HA as an rhBMP-2 carrier.
In vivo study using microcomputerized tomography (micro-CT) scanning.
Seventy-six New Zealand white male rabbits were randomized into a single control group (n=14) without rhBMP-2 and four experimental groups (10 μg, 50 μg, 200 μg, and 500 μg of rhBMP-2; n=14 in each group). The subjects were divided into 3- and 6-week groups.
Outcome was evaluated by radiography, bending test, three-dimensional micro-CT, and histologic examinations.
Bilateral posterolateral fusion was carried out, and rhBMP-2 (0, 10, 50, 200, 500, 1,000, and 2,000 μg) was implanted into the bilateral transverse processes using HA as a carrier.
The fusion rates of the 3-week group were 83.3% for 50 and 200 μg of rhBMP-2 and 100% for 500 μg. The improved fusion rates of the 50 μg or higher groups compared with those of control were statistically significant. The fusion rates of the 6-week group were 75% for 10 μg of rhBMP-2 and 100% for 50 μg or higher. Similarly, the improved fusion rates of the 10 μg or higher groups compared with those of control were statistically significant. Significantly higher percent volumes were observed in the 3-week 200 μg of rhBMP-2 group and 6-week 200 μg of rhBMP-2 group than the 3-week HA group and 6-week HA group, respectively. Trabecular thickness was significantly higher in the 3-week 200 μg of rhBMP-2 group than the 3-week HA group. Histologic analysis of the 10 μg group showed bone tissues within the pores from 3 weeks, and this was observed more vividly in the 50, 200, and 500 μg groups. The 6-week 10 μg and 50 μg of rhBMP-2 groups had lower amounts of new tissue but higher portions of complete bone tissue within the HA specimen, along with higher formation of completely reconstituted bone tissues outside HA.
Injection of 50 μg or more of E. coli-derived rhBMP-2 into a HA carrier induced earlier bone fusion in the intertransverse process of rabbits, which confirms the excellent bone forming ability of E. coli-derived rhBMP-2 and the suitability of HA as a carrier of rhBMP-2.
The spine journal: official journal of the North American Spine Society 02/2012; 12(3):239-48. · 2.90 Impact Factor
ABSTRACT: In the laminectomy model in rats, to verify anti-adhesive effectiveness of the new material, a mixture composed of poloxamer 407, calcium chloride, and xanthorrhizol, we compared it with that of commercially used solution form anti-adhesive agent GUARDIX-SL, Biorane.
A total of 108 Sprague-Dawley rats (SD rats) were divided equally into three groups: negative control group (NCG), positive control group (PCG), and experimental group (EG). After exposing the dura on L4 level, we closed the wound shortly after hemostasis, after administering the anti-adhesive agent. To evaluate effectiveness, 18 SD rats from each group were killed after 1 week of rearing. Nine were examined by grading of gross adhesion and the other nine, by grading of histological adhesion. The degree of adhesion in the remainder of 18 SD rats in each group was examined with the same method after four weeks of rearing.
Comparing the degree of adhesion after growth for 1 week, the gross and histological adhesion of the EG was lower than that of the NCG. There was no statistical significance in the gross score (P = 0.63), but there was statistical significance in the histological score (P = 0.04). The EG showed similar or improved degrees of adhesion in comparison with the PCG. In comparison after growth for 4 weeks, although gross adhesion of the EG was not significantly lower than the NCG, histological adhesion was remarkably low in the EG (P = 0.01). The EG showed similar or improved degrees of gross and histological adhesion in comparison to that of the PCG. (P = 0.20, 0.07).
The new anti-adhesive material showed similar or improved effectiveness with the existing agents for commercial use. This result suggests that the new anti-adhesive material will be a successful candidate as a future product for clinical use.
European Spine Journal 12/2011; 21(5):971-9. · 1.97 Impact Factor
ABSTRACT: A retrospective study.
To analyze the treatment outcome of patients with lower thoracic and lumbar fractures combined with neurological deficits.
Although various methods of the surgical treatment for lower thoracic and lumbar fractures are used, there has been no surgical treatment established as a superior option than others.
Between March 2001 and August 2009, this study enrolled 13 patients with lower thoracic and lumbar fractures who underwent spinal canal decompression by removing posteriorly displaced bony fragments via the posterior approach and who followed up for more than a year. We analyzed the difference between the preoperative and postoperative extents of canal encroachment, degrees of neurologic deficits and changes in the local kyphotic angle.
The average age of the patients was 37 years. There were 10 patients with unstable burst factures and 3 patients with translational injuries. Canal encroachment improved from preoperative average of 84% to 9% postoperatively. Local kyphosis also improved from 20.5° to 1.5°. In 92% (12/13) of the patients, neurologic deficit improved more than Frankel grade 1 and an average improvement of 1.7 grade was observed. Deterioration of neurologic symptoms was not observed. Although some loss of reduction of kyphotic deformity was observed at the final follow-up, serious complications were not observed.
When posteriorly displaced bony fragments were removed by the posterior approach, neurological recovery could be facilitated by adequate decompression without serious complications. The posterior direct decompression could be used as one of treatments for lower thoracic and lumbar fractures combined with neurologic injuries.
Asian spine journal 09/2011; 5(3):146-54.
ABSTRACT: A retrospective study.
To comparatively investigated the rate of the adjacent segment degeneration and the clinical outcomes in patients with spondylolytic spondylolisthesis, spinal stenosis or degenerative spondylolisthesis.
There have been few studies reported on the adjacent segment degeneration following posterior lumbar interbody fusion(PLIF). Many risk factors for the adjacent segment degeneration following PLIF have been proposed. The range of decompression has been presented as one of the risk factors, yet controversial.
This study enrolled sixty-three patients who had been treated with single-level PLIF and who were followed up for more than two years. The patients were divided into 3 groups based on the preoperative diagnosis. We analyzed the difference between the preoperative and postoperative intervertebral disc heights of the superior adjacent segments. The incidence rates of instability and the clinical outcomes were comparatively analyzed between each group.
The average age of the patients was 55.8 years in the spondylolytic spondylolisthesis group, 65.9 years in the degenerative spondylolisthesis group and 60.4 years in the spinal stenosis group. The average follow-up period was 44 months, 43 months and 42 months, respectively. At the last follow-up, compared to the preoperative period, the intervertebral disc height decreased in all three groups. A statistically significant decrease (p < 0.01) was observed only in the spondylolytic spondylolisthesis group and no significant difference was observed between each group (p = 0.41). The incidence rate of instability and the clinical outcome were not significantly different between each group.
Spondylolytic spondylolisthesis with total laminectomy and single-level PLIF showed no significant difference in the superior adjacent segment degeneration and instability, and the clinical outcome as compared to that of partial laminectomy with single-level PLIF for treating degenerative spondylolisthesis or spinal stenosis.
Asian spine journal 06/2011; 5(2):82-90.
ABSTRACT: The purposes of the present study are to evaluate the subsidence and nonunion that occurred after anterior cervical discectomy and fusion using a stand-alone intervertebral cage and to analyze the risk factors for the complications.
Thirty-eight patients (47 segments) who underwent anterior cervical fusion using a stand-alone polyetheretherketone (PEEK) cage and an autologous cancellous iliac bone graft from June 2003 to August 2008 were enrolled in this study. The anterior and posterior segmental heights and the distance from the anterior edge of the upper vertebra to the anterior margin of the cage were measured on the plain radiographs. Subsidence was defined as ≥ a 2 mm (minor) or 3 mm (major) decrease of the segmental height at the final follow-up compared to that measured at the immediate postoperative period. Nonunion was evaluated according to the instability being ≥ 2 mm in the interspinous distance on the flexion-extension lateral radiographs.
The anterior and posterior segmental heights decreased from the immediate postoperative period to the final follow-up at 1.33 ± 1.46 mm and 0.81 ± 1.27 mm, respectively. Subsidence ≥ 2 mm and 3 mm were observed in 12 segments (25.5%) and 7 segments (14.9%), respectively. Among the expected risk factors for subsidence, a smaller anteroposterior (AP) diameter (14 mm vs. 12 mm) of cages (p = 0.034; odds ratio [OR], 0.017) and larger intraoperative distraction (p = 0.041; OR, 3.988) had a significantly higher risk of subsidence. Intervertebral nonunion was observed in 7 segments (7/47, 14.9%). Compared with the union group, the nonunion group had a significantly higher ratio of two-level fusion to one-level fusions (p = 0.001).
Anterior cervical fusion using a stand-alone cage with a large AP diameter while preventing anterior intraoperative over-distraction will be helpful to prevent the subsidence of cages. Two-level cervical fusion might require more careful attention for avoiding nonunion.
Clinics in orthopedic surgery 03/2011; 3(1):16-23.