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 %  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 CTCT / Myelogram SI injection Exploration Extraction / Revision No 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