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Biomedical subjects

John M Mathis

Publications and source records attributed to John M Mathis.

8 recordsLinked to original sources
PubMed2003

The effect of vertebral body percentage fill on mechanical behavior during percutaneous vertebroplasty.

STUDY DESIGN: An ex vivo biomechanical study was conducted using osteoporotic cadaveric vertebral bodies. OBJECTIVE: To determine the relationship between the percentage of osteoporotic vertebral body volume filled with polymethylmethacrylate cement during percutaneous vertebroplasty and the percentage restoration of strength and stiffness. SUMMARY OF BACKGROUND DATA: A previous biomechanical study reported a weak relationship between the volume of cement injected and restoration of vertebral body strength and stiffness. Vertebral bodies vary considerably in size among regions and among spines, and the weak correlation may be attributed to the fact that the volume of vertebral bodies was not explicitly considered. METHODS: The volume of 120 vertebral bodies (T6-L5) harvested from 10 osteoporotic female cadaver spines was determined by Archimedean displacement. Compression fractures were experimentally created, and initial strength and stiffness were determined. The vertebral bodies were stabilized using bipedicular injections of 2-8 mL of cement and then recompressed, after which posttreatment strength and stiffness were measured. Linear regression was used to analyze the relationship between percentage of volume fill and percentage of restored stiffness and strength. RESULTS: The correlations between percentage of fill and restored strength and stiffness were weak: r2 = 0.21 and r2 = 0.27, respectively. On average, restoration of strength and stiffness required vertebral body cement fills of 16.2% and 29.8%, respectively. CONCLUSION: Strength and stiffness are weakly correlated with the percentage fill volume of cement injected during vertebroplasty.

Absorptiometry, Photon↗
PubMed2003

Percutaneous vertebroplasty: technical considerations.

Percutaneous vertebroplasty has now been in use in the United States for 10 years. Standards of practice are available from the American College of Radiology. The performance of this procedure is becoming routine for most interventional practices, and it has become the general standard of care for pain associated with vertebral compression fractures of the spine. This article describes routine procedural technique and considerations and is intended to review the authors' knowledge of the procedure and provide reliable methods for good outcomes and complication avoidance.

Analgesia↗
PubMed2002

The pharmaceuticals and materials used in common spine interventions.

Image-guided spine interventions are rapidly increasing in number in the realm of the interventional radiologist. Appropriate selection and understanding of the pharmaceuticals used in these procedures is necessary to minimize complications and maximize successful outcomes.

Anesthetics, Local↗
PubMed2002

Vertebroplasty in osteoporosis.

Percutaneous vertebroplasty (PV) is a safe and effective treatment for relieving pain in patients complaining of severe back pain induced by osteoporotic compression fractures. The success rate exceeds 90% and the complication rate is lower than 1%. Most of the complications are transient and should be avoided using good technique. The classic indication for PV is severe, persistent, and incapacitating focal back pain not responding to standard medical therapy and related to one or more collapsed vertebral bodies of 4 to 12 weeks duration. PV should be used earlier in patients at risk of immobilization complications and requiring narcotics. PV should be always considered as a good alternative treatment compared with medical therapy in patients with pain and osteoporotic compression fractures.

Bone Cements↗
PubMedDate not supplied

Ex vivo biomechanical comparison of hydroxyapatite and polymethylmethacrylate cements for use with vertebroplasty.

BACKGROUND AND PURPOSE: Little is known about the mechanical stabilization afforded by new materials proposed for use with vertebroplasty. This comparative ex vivo biomechanical study was designed to determine the strength and stiffness of osteoporotic vertebral bodies (VBs) subjected to compression fractures and stabilized with bipedicular injections of Cranioplastic altered in a manner consistent with the practice of vertebroplasty or BoneSource cement. METHODS: VBs T8-T10 and L2-L4 from 10 fresh spines were harvested from female cadavers (aged 91.5 years +/- 3.9 at death). These were screened for bone density (t score, -4.9 +/- 1.4; bone mineral density, 0.61 g/cm(2) +/- 0.19), disarticulated, and compressed to determine initial strength and stiffness. The fractured VBs were stabilized with bipedicular injections of a predetermined quantity and type of cement and then re-crushed. RESULTS: At both the thoracic and lumbar levels, VBs repaired with altered Cranioplastic resulted in significantly greater strength (P <.05) than that in their prefracture states, whereas those repaired with BoneSource were restored to their initial strength. Cranioplastic resulted in significantly stronger repairs than BoneSource in the thoracic region; however, repair strengths in the lumbar region were not significantly different. The repaired stiffness was significantly lower than the initial stiffness in all treatments and in both regions. Differences in the repaired stiffness between the treatment groups in either region and differences in the mechanical parameters obtained by adding an additional 2 mL of BoneSource were not significant. CONCLUSION: Both materials in the volumes used either restored or increased VB strength, but none restored stiffness.

Aged↗