A Modified Unilateral Extrapedicular Approach Applied to Percutaneous Kyphoplasty to Treat Lumbar Osteoporotic Vertebral Compression Fracture: A Retrospective Analysis.

BACKGROUND: In recent years, many extrapedicular puncture methods have been applied to percutaneous kyphoplasty (PKP) in the treatment of osteoporotic vertebral compression fractures (OVCFs). However, these techniques were generally complex and had the risk of some puncture-related complications, which greatly limited the wide applications in PKP. Finding a safer and more feasible extrapedicular puncture method was rather important. OBJECTIVES: To evaluate the treatment effect of modified unilateral extrapedicular PKP in patients with lumbar OVCFs clinically and radiologically. STUDY DESIGN: Retrospective study. SETTING: Department of Orthopedic Surgery, an affiliated hospital of a medical university. METHODS: Patients who were treated by modified unilateral extrapedicular PKP in our institution, from January 2020 to March 2021, were retrospectively enrolled. The degree of pain relief and functional recovery were evaluated by the Visual Analog Scale (VAS) and the Oswestry Disability Index (ODI), respectively. Radiologic results were assessed including anterior vertebral height (AVH) and kyphotic angle. In addition, volumetric analysis was performed to evaluate bone cement distribution. And the intraoperative data and complications were also recorded. RESULTS: A total of 48 patients with lumbar OVCFs were successfully treated by modified unilateral extrapedicular PKP. All patients experienced a significant decrease in VAS and ODI scores after surgery (P < 0.01) and maintained the statistical significance until the last follow-up (P < 0.01), as well as significant AVH restoration (P < 0.01) and kyphotic angle correction (P < 0.01) compared with preoperative corresponding values. Volumetric analysis showed that all cases of bone cement diffused across the midline of the vertebral body (VB), in which 43 patients (89.6%) presented optimal contralateral distribution with good or excellent bone cement spread. In addition, 8 patients (16.7%) experienced asymptomatic cement leakage, and no other severe complications, such as injuries to segmental lumbar arteries and nerve roots, were found. LIMITATIONS: A noncontrol study with a small patient population and short follow-up duration. CONCLUSIONS: Modified unilateral extrapedicular PKP, in which the puncture trajectory was advanced through the bottom of Kambin's triangle to or across the midline of VB for proper bilateral cement distribution, greatly alleviated back pain and restored the morphology of fractured vertebrae. It seemed to be a safe and effective alternative applied to treat lumbar OVCFs with appropriate patient selection.

T allele at site 6007 of bone morphogenetic protein-4 gene increases genetic susceptibility to ossification of the posterior longitudinal ligament in male Chinese Han population.

BACKGROUND: Several candidate genes of ossification of the posterior longitudinal ligament (OPLL) susceptibility have been identified, but their polymorphisms account for only a small percent of the total variance. Bone morphogenetic protein-4 (BMP4) is a potent ectopic ossification inducing factor. BMP4 protein and mRNA are present in cells from OPLL patients, but not non-OPLL controls. A single nucleotide polymorphism of 6007C>T(rs17563) of BMP4 has been reported to affect bone density in postmenopausal women. Thus, BMP4 may function in OPLL development. Appropriately, the relationship between BMP4 polymorphisms and OPLL was investigated. METHODS: A case-control association study investigated the genetic etiology in 179 OPLL patients and 298 non-OPLL controls. Extent of OPLL was analyzed by radiologic examinations. Whether single nucleotide polymorphism (SNP) of -5826G>A(rs1957860) 5' of the transcription start site and 6007C>T(rs17563) in exon 4 of the BMP4 gene were statistically associated with genetic susceptibility to OPLL in Chinese Han subjects was assessed. RESULTS: A significant statistical difference in genotype of 6007C>T polymorphism between male OPLL patients and male controls was evident, and the frequency of "TT" genotype in male OPLL patients was significantly higher than in male controls (P = 0.039). The frequency of the "T" allele was also significantly higher in male OPLL subjects than in male controls (P = 0.014, OR = 1.57). A significant difference was also observed between the 6007C>T polymorphism and the number of ossified cervical vertebrae in OPLL patients, while no statistical difference was apparent between the -5826G>A polymorphism and OPLL occurrence. CONCLUSIONS: The T allele in the 6007C>T polymorphism may be a risk factor for male Han Chinese with ossification of the posterior longitudinal ligament in the cervical spine. Chinese Han male patients with CT and TT 6007C>T genotypes have a genetic susceptibility to OPLL and more extensive OPLL in the cervical spine.

Association between two polymorphisms of the bone morpho-genetic protein-2 gene with genetic susceptibility to ossification of the posterior longitudinal ligament of the cervical spine and its severity.

BACKGROUND: Ossification of the posterior longitudinal ligament (OPLL) has a strong genetic background. Previous studies have shown that bone morphogenetic protein-2 (BMP2) and BMP2 mRNA are expressed in ossifying matrix and chondrocytes adjacent to cartilaginous areas of OPLL tissues and mesenchymal cells with fibroblastic features in the immediate vicinity of the cartilaginous areas. It is suggested that BMP2 plays different roles in the different stages of development of OPLL. However, it remains unknown which factors induce ligament cells to produce BMP2. METHODS: OPLL patients (n = 192) and non-OPLL controls (n = 304) were studied. Radiographs of the cervical spine were analyzed for extent of OPLL. We investigated whether single nucleotide polymorphisms of exons 3 (-726) T/C and 3 (-583) A/G in the BMP2 gene are statistically associated with genetic susceptibility to OPLL in Chinese Han subjects. RESULTS: There was no statistical difference between the occurrence of exons 3 (-726) T/C and 3 (-583) A/G and the occurrence of OPLL in the cervical spine. However, there was a significant association between occurrence of exon 3 (-726) T/C polymorphism and occurrence of OPLL in males of cases and controls in the cervical spine. In addition, no significant association was found between the exons 3 (-726) T/C and 3 (-583) A/G with number of ossified cervical vertebrae in OPLL patients. CONCLUSIONS: Exon 3 (-583) A/G polymorphism in BMP2 gene is not associated with the occurrence and the extent of OPLL in the cervical spine. Chinese Han male patients with TC and CC genotypes in exon 3 (-726) T/C have genetic susceptibility to OPLL but not to more extensive OPLL in the cervical spine.