PubMed Health⌕ Search

Biomedical subjects

Isador Lieberman

Publications and source records attributed to Isador Lieberman.

8 recordsLinked to original sources
PubMed2006

The biomechanics of 1, 2, and 3 levels of vertebral augmentation with polymethylmethacrylate in multilevel spinal segments.

STUDY DESIGN: Experimental biomechanics of multilevel segments with 0, 1, 2, and 3 vertebral levels of polymethylmethacrylate augmentation. OBJECTIVE: To compare multilevel spinal segments with different numbers (0, 1, 2, and 3) of vertebral levels augmented with polymethylmethacrylate. SUMMARY OF BACKGROUND DATA: The stiffness and strength of single-level polymethylmethacrylate augmentations in individual and multilevel vertebrae treated by kyphoplasty and vertebroplasty have been studied, but the biomechanics of multilevel segments with more than 1 vertebral level augmented with polymethylmethacrylate are lacking, yet this is clinically relevant in multilevel compression fracture treatment. MATERIALS AND METHODS: A total of 48 multilevel segments (T3-T5, T6-T8, T9-T11, T12-L2, and L3-L5) from 12 spines with known bone mineral density (BMD) were allocated into 6 groups based on the number of vertebral levels augmented: 0 levels (n = 13), control group; 1 level (n = 7), group 2; 2 levels, groups 3, 4, and 5 (n = 7 in each); and 3 levels (n = 7), group 6. They were compressed to failure, disarticulated into individual vertebrae, and retested. Stiffness and strength were statistically analyzed using a univariate analysis of variance comparing the main effects, using least significant difference comparisons with 0.05 probability level. RESULTS: Strength was dependent on BMD (P < 0.001 multilevel segments, P < 0.001 individual vertebrae), with no differences among the 6 different augmentation groups, and no significant differences between augmented and nonaugmented individual vertebrae. Stiffness was dependent on BMD (P = 0.009 multilevel segments, P < 0.004 individual vertebrae), with no significant differences among the 6 different augmentation groups, and no significant differences between augmented and nonaugmented individual vertebrae. CONCLUSIONS: Multilevel segment biomechanics are dependent on BMD and not the pattern of augmentation, so the augmentation of fractured vertebrae can be extended to adjacent levels at risk for fracture to maintain stiffness and strength, thus preventing further fractures.

Aged↗
PubMed2006

Nonseminomatous germ cell tumor after chemotherapy with residual mass invading the spine.

Bony metastasis is a rare feature of metastatic nonseminomatous germ cell tumor. A 25 year-old man presented with back pain radiating down both legs, and a subsequent work-up demonstrated a right-sided testicular mass with bilateral retroperitoneal lymphadenopathy and tumor involvement of the L2 vertebra. Radical inguinal orchiectomy confirmed nonseminomatous germ cell tumor, and the patient underwent chemotherapy with a residual mass and vertebral involvement by MRI. Combined vertebral resection with spinal reconstruction and retroperitoneal lymph node dissection demonstrated residual fibrosis. While bony metastasis of nonseminomatous germ cell tumors is rare, resection with spinal reconstruction can be accomplished with acceptable morbidity.

Adult↗
PubMed2005

Biomechanical comparison of transarticular facet screws to lateral mass plates in two-level instrumentations of the cervical spine.

STUDY DESIGN: In vitro biomechanical comparison of transarticular facet screws to lateral mass plates in two level instrumentations of the cervical spine. OBJECTIVE: Lateral mass plates are costly, and screw placement is difficult. Facet screws have never been tested as an alternative in the cervical spine. This biomechanical study compared cervical transarticular facet screws to lateral mass plates in two-level instrumentations of human cadaveric cervical spines. SUMMARY OF BACKGROUND DATA: Translaminar facet screws have been shown to have similar biomechanical performance to pedicle screw fixation in the lumbar spine, especially in flexion. They have proven to be fast, safe, and effective, with authors reporting 94% to 100% fusion rates in single-level lumbar fusions. However, a biomechanical comparison of transarticular facet screws to lateral mass plates in cervical spine instrumentations has not been reported. METHODS: Thirteen human cadaveric cervical motion segments (C2-C4, C5-C7) were tested before and after instrumentation, with either transarticular facet screws or lateral mass plates, in flexion, extension, lateral bending, and torsion. Specimens were subjected to six cycles under a load of 2 Nm. RESULTS: Both fixation systems significantly reduced range of motion (ROM) and increased stiffness compared with the intact state in flexion, extension, lateral bending, and torsion. There were also no significant differences between the facet screws and plates in any of the four directions. To compare the two systems, ROM of each was analyzed relative to the uninstrumented state. Flexion was 0.26 (or 26% of the intact state) for the transarticular facet screws versus 0.20 for the lateral mass plates (P = 0.34), extension was 0.10 versus 0.07 (P = 0.43), lateral bending was 0.17 versus 0.15 (P = 0.52), and torque was 0.25 versus 0.38 (P = 0.12). Load to failure testing failed to indicate any differences between the two methods of fixation because all the specimens failed elsewhere. CONCLUSION: This study proves that transarticular facet screws and lateral mass plates are equivalent in two-level instrumentations of the cervical spine. This is the first biomechanical study to test transarticular facet screws in this context.

Aged↗
PubMed2004

Primary and secondary osteoporosis' incidence of subsequent vertebral compression fractures after kyphoplasty.

STUDY DESIGN: Retrospective review of prospective database. OBJECTIVES: Define the incidence of adjacent and remote fractures after kyphoplasty vertebral augmentation, and identify vulnerable subpopulations at increased risks. SUMMARY OF BACKGROUND DATA: Painful osteoporotic compression fractures can be effectively treated with methyl methacrylate vertebral augmentation, but the effect of intervention on the generation of future remote and adjacent fractures has not been identified. No paper has analyzed the association of long-term steroid use to subsequent compression fractures. METHODS: A total of 175 patients were treated for compression fractures, from October 1999 to November 2001, 60 patients were excluded due to insufficient follow-up (less than 3 months) or malignancy related fracture. The remaining 115 patients' charts and radiographs were then individually analyzed. New fractures were identified based on changes from baseline imaging studies (). Demographic information, vertebral levels treated, adjacent fractures, and remote fractures underwent statistical analyzed (P < 0.05). RESULTS: A total of 225 vertebral bodies were treated in 115 patients using the kyphoplasty technique; of those, 26 patients developed 34 subsequent compression fractures. The mean follow-up was 11 months (range, 3-33 months). The incidence of subsequent fracture per procedure per kyphoplasty was 15.1% (34 of 225), overall incidence per patient was 22.6% (26 of 115). There were 80 patients with primary osteoporosis and 35 patients with secondary steroid-induced osteoporosis. These populations were similar in terms of demographics, single or multiple sites, along with two or three adjacent levels treated. Seventeen of the 26 (65%) patients with subsequent fracture had secondary steroid-induced osteoporosis, while only 9 of the 26 (35%) patients had primary osteoporosis. Therefore, the incidence of post-kyphoplasty VCF in the primary osteoporotic patient was 11.25% (9 of 80) and the incidence in the steroid-induced osteoporotic patient was 48.6% (17 of 35). This increased fracture rate in the steroid-dependent patients was significant (P < 0.0001), along with adjacent fractures (12 of 19 on steroids, P = 0.0009), and remote fractures (7 of 9 on steroids, P = 0.027). CONCLUSIONS: Steroid-induced compression fractures appear to have an increased incidence of subsequent fractures after the kyphoplasty procedure. The kyphoplasty protocol with concurrent medical osteoporotic regimen does not appear to increase, and may serve to reduce, the incidence of remote and adjacent fractures for primary osteoporotic fractures.

Aged↗
PubMed2003

Vertebroplasty and kyphoplasty for osteolytic vertebral collapse.

As many as 70% of patients with cancer and multiple myeloma initially present with osteolytic involvement of the spine. These vertebral fractures are associated with significant morbidity and mortality and represent a tremendous personal and societal burden. Traditional medical and surgical options often are inadequate or too invasive for this population debilitated by cancer. Vertebroplasty involves the injection of polymethylmethaerylate to strengthen a vertebra. This minimally invasive method, which has been adopted by practitioners during the past decade to treat symptomatic osteoporotic compression fractures is reported to provide quick pain relief in 90% of patients, with only infrequent, mostly minor, complications. In patients with osteolytic fractures, vertebroplasty is associated with an increased rate of cement leak and less predictable pain relief. Kyphoplasty is an extension of vertebroplasty that uses an inflatable bone tamp to restore the vertebral body toward its original height while creating a cavity to be filled with bone cement. Preliminary data indicate that kyphoplasty is a safe procedure associated with a lower risk of cement leak, restoration of vertebral body height, and sagittal spinal alignment. In patients with osteolytic fractures secondary to multiple myeloma, kyphoplasty yields quick pain relief, and is associated with a statistically significant improvement in generic health outcome measures.

Bone Cements↗
PubMed2002

Multiple myeloma: present and future.

Multiple myeloma is a clonal B-cell tumor of slowly proliferating plasma cells within the bone marrow. Among hematologic malignancies, it constitutes 10% of the cancers and ranks as the second most frequently occurring hematologic cancer in the United States, after non-Hodgkin lymphoma. Interleukin-6 is an important cytokine in myeloma cell growth and proliferation. Close cell-to-cell contact between myeloma cells and the bone marrow stromal cells triggers a large amount of interleukin-6 production, which supports the growth of these cells, as well as protecting them from apoptosis induced by dexamethasone and other chemotherapeutic agents. Therapies modulating the tumor and its microenvironment are being actively pursued with the goal of converting multiple myeloma to a chronic disease with the patients maintaining a normal lifestyle.

Angiogenesis Inhibitors↗