Re: Re: one thing that really disturbs meaboutrevision surgery

[Guest guest]

, I thought you said they were all pre-bent. How can they be both?

Re: [ ] one thing that really disturbs me> >> aboutrevision surgery> >> > >> > >> > >> > >> > >> Hi...> >> > >> I finally found what you mentioned:> >> > >> 1: Spine. 2005 Feb 15;30(4):375-9. Links> >> The memory properties of cold-worked titanium rods in scoliosis> >> constructs.> >> > >> * Burger EL,> >> * Baratta RV,> >> * King AG,> >> * Easton R,> >> * Lu Y,> >> * ow M,> >> * Riemer BL.> >> > >> Department of Orthopedics, Bioengineering Laboratory, Louisiana State> >> University Health Sciences Center, New Orleans, Louisiana 70112, USA.> >> EBurge1@...> >> > >> STUDY DESIGN: Time series monitoring changes in titanium and stainless> >> steel rod curvature kept at a constant temperature of 37 C as a function of> >> time. OBJECTIVES: To assess the possibility of loss of curvature in titanium> >> rods after scoliosis surgery. SUMMARY OF BACKGROUND DATA: Titanium rods have> >> gained use in scoliosis surgery due to their excellent biocompatibility,> >> while allowing medical personnel to obtain undistorted magnetic resonance> >> imaging scans following surgery. However, the impression of several> >> clinicians has been that when screw pullout and/or loss of sagittal balance> >> occurs, it may be due to the rods losing some of their curvature. METHODS:> >> Five 6-mm rods of differing compositions and lengths (titanium 300 and 100> >> mm, stainless steel 300 and 100 mm, prebent titanium 85 mm) were bent at> >> room temperature with a 3-point rod bender, then placed in an incubator at> >> 37 C. Digital photographs were taken every 2 weeks and analyzed to extract> >> the radius of curvature of each rod. RESULTS: The Ti rods had a> >> significantly decreasing curvature with time. The prebent Ti and stainless> >> steel rods did not exhibit significant change in curvature. CONCLUSIONS:> >> Titanium rods bent at room temperature and then exposed to body temperature> >> over time tend to exhibit "metal memory"; they gradually revert to their> >> original shape. This may result in loss of sagittal balance and/or proximal> >> screw pullout.> >> > >> PMID: 15706332 [PubMed - indexed for MEDLINE]> >> > >> I'm going to have to ask some questions about this, as I don't understand> >> the results:> >> > >> > >>> RESULTS: The Ti rods had a significantly decreasing curvature with time.> >>> The prebent Ti and stainless steel rods did not exhibit significant change> >>> in curvature.> >>> > >> Did the titanium rods lose their curves or not? In today's scoliosis> >> surgeries, all rods are pre-bent.> >> > >>> > >> Regards,> >> > >>>>

[Guest guest]

Hi...

I was thinking pre-bent, as in they are bent in the operating room before being placed in the patient. I can’t think of any way a surgeon could possibly use rods that were bent in the factory.

--

On 7/31/06 12:59 PM, " Sharon Green " <sharon.green18@...> wrote:

, I thought you said they were all pre-bent. How can they be both?

Re: [ ] one thing that really disturbs

me

> >> aboutrevision surgery

> >>

> >>

> >>

> >>

> >>

> >> Hi...

> >>

> >> I finally found what you mentioned:

> >>

> >> 1: Spine. 2005 Feb 15;30(4):375-9. Links

> >> The memory properties of cold-worked titanium rods in

scoliosis

> >> constructs.

> >>

> >> * Burger EL,

> >> * Baratta RV,

> >> * King AG,

> >> * Easton R,

> >> * Lu Y,

> >> * ow M,

> >> * Riemer BL.

> >>

> >> Department of Orthopedics, Bioengineering Laboratory,

Louisiana State

> >> University Health Sciences Center, New Orleans, Louisiana

70112, USA.

> >> EBurge1@...

> >>

> >> STUDY DESIGN: Time series monitoring changes in titanium

and stainless

> >> steel rod curvature kept at a constant temperature of 37 C as

a function of

> >> time. OBJECTIVES: To assess the possibility of loss of

curvature in titanium

> >> rods after scoliosis surgery. SUMMARY OF BACKGROUND DATA:

Titanium rods have

> >> gained use in scoliosis surgery due to their excellent

biocompatibility,

> >> while allowing medical personnel to obtain undistorted

magnetic resonance

> >> imaging scans following surgery. However, the impression of

several

> >> clinicians has been that when screw pullout and/or loss of

sagittal balance

> >> occurs, it may be due to the rods losing some of their

curvature. METHODS:

> >> Five 6-mm rods of differing compositions and lengths (titanium

300 and 100

> >> mm, stainless steel 300 and 100 mm, prebent titanium 85 mm)

were bent at

> >> room temperature with a 3-point rod bender, then placed in an

incubator at

> >> 37 C. Digital photographs were taken every 2 weeks and

analyzed to extract

> >> the radius of curvature of each rod. RESULTS: The Ti rods had a

> >> significantly decreasing curvature with time. The prebent Ti

and stainless

> >> steel rods did not exhibit significant change in curvature.

CONCLUSIONS:

> >> Titanium rods bent at room temperature and then exposed to

body temperature

> >> over time tend to exhibit " metal memory " ; they gradually revert

to their

> >> original shape. This may result in loss of sagittal balance

and/or proximal

> >> screw pullout.

> >>

> >> PMID: 15706332 [PubMed - indexed for MEDLINE]

> >>

> >> I'm going to have to ask some questions about this, as I don't

understand

> >> the results:

> >>

> >>

> >>> RESULTS: The Ti rods had a significantly decreasing curvature

with time.

> >>> The prebent Ti and stainless steel rods did not exhibit

significant change

> >>> in curvature.

> >>>

> >> Did the titanium rods lose their curves or not? In today's

scoliosis

> >> surgeries, all rods are pre-bent.

> >>

> >>>

> >> Regards,

> >>

> >>>

>