Daniel Boedeker, MD

Spinal Hardware Extraction

Spinal instrumentation has been utilized since the 1940s

Pedicle screws became increasingly popular in the 1980s with both plate and rod versions

Despite legal turmoil in the early 1990s they have ultimately been found to be a safe and effective means of stabilizing the posterior spine and attaining fusion

Pedicle Screws

Purpose of pedicle screws is to limit motion and enhance successful fusion

Most studies show improved outcomes with complete fusion, usually determined radiographically

Typically follow fusion patients for several months post operatively with periodic x-rays

Pedicle Screws

Problem is that radiographic determination of fusion is difficult

30 – 40% of the time the radiographic interpretation was found to be wrong at surgery

Pedicle Screws

Persistent back pain is the most common complaint following spinal fusion

Incidence in literature is highly variable with studies showing 22-100%

Many factors can result in post fusion back pain

Lumbar Fusion

Among the causes of post fusion back pain can be: Pseudoarthrosis Malpositioned hardware Adjacent segment disease SI joint pain Painful hardware

Lumbar Fusion

Continued pain after reasonable time and adequate rehab bears further investigation

Depending on nature of the pain testing such as CT scanning is appropriate

CT allows for 3 dimensional evaluation of hardware position as well as quality of the fusion

Even CT can be misinterpreted with regard to quality of fusion

Persistent Pain

Tenderness to palpation over hardware can be indicative of painful hardware

Best test is hardware block though this is not perfect

These two findings are the most predictive of improvement in pain after hardware extraction

Both rely on subjective report from patient

Persistent Pain

There are no prospective studies evaluating the benefit of spinal hardware extraction

Several retrospective studies show statistically significant improvement in pain and functional status after hardware removal

Hardware Extraction

Biomechanical studies show removal of hardware decreases stress on adjacent disks, potentially limiting adjacent segment disease

Increasing flexibility after hardware removal may decrease stress shielding effects at adjacent levels

Hardware Extraction

Aside from pain there are other potential reasons to extract hardware

Some thought that previous infection is an indication for hardware removal after successful fusion is achieved

Allergy to metal alloy is rare but reported issue that may necessitate extraction

Manufacturers routinely recommend extraction for all hardware

Hardware Extraction

In some long construct fusions, such as thoracolumbar trauma, extraction has been associated with progressive deformity

Hardware Extraction

Hardware Injection

Pain After Fusion

Tender to Palpation

Infection

Not Tender

CT CT / Myelogram

SI injection

Exploration Extraction /

RevisionNo Action

Summary

Persistent back pain after instrumented fusion is multifactorial

Among the causes of post fusion pain is symptomatic hardware

No strong data exists to give guidance with regard to hardware removal

Undoubtedly helpful in some patients, but not all