Total Disc Replacement

function of intervertebral discs

shock absorbers, maintain spinal alignment, facilitate ROM

factors that contribute to disc degeneration

age, genetics, mechanical stress/loading, nutrition, smoking, sedentary lifestyle, hormones

failure rate of conservative treatment of disc degeneration

20-30% of patients

traditional surgical options for disc degeneration

discectomy and vertebral arthrodesis (fusion)

cons of fusions

decreased ROM, redistributes load to adjacent vertebrae, adjacent segment disease

purpose of a total disc replacement

address fusion-related complications, recreate normal disc biomechanics, maintain load distribution

which is better disc arthroplasty or arthrodesis

arthroplasty (replacement)

benefits of disc replacement compared to discectomy/arthrodesis

less pain and NDI, better neurological success, more ROM, decreased incidence of reoperation, decreased risk of ASD

how to differentiate pain from the discs vs the facets

pt will have more pain with compression if it is a disc problem and more pain with extension if it is a facet problem

cluster of indications for a disc replacement

18-60 years, LBP, no radicular sxs, sxs with flexion, failure of conservative management, ODI >40%

contraindications to disc replacements

scoliosis, osteoporosis, ankylosing spondylitis (rheumatic conditions), previous major abdominal surgery, radiculopathy, facet joint degeneration

approach to disc replacement surgery

anterior approach to reduce risk of SCI

complications following a lumbar disc replacement

vascular injury (L common iliac vein), retrograde ejaculation, abdominal wall weakness

risk factors of poor prognosis of disc replacement

instability, prolonged sxs, severe pathology, poor health, prolonged sick leave

complications following disc replacement surgery

implant migration (instability), facet degeneration, heterotropic ossification, ASD, failure

reasons for implant instability

subsidence, anteroposterior migration

subsidence

axial migration where the implant sinks into the vertebral endplates

factors contributing to facet joint degeneration following disc replacement

improper placement of the disc anteriorly increases facet loading, removal of ALL during surgery increases extension

factors contributing to adjacent segment disease following a disc replacement

preexisting degeneration, age, malpositioning of the implant

major risk factor for failure of disc replacement surgery

diabetes

what happens when a disc replacement fails

most of the time a lumbar fusion is done

precautions after a disc replacement

no lifting/twisting 4-6 weeks, return to work in 2-6 weeks, return to sport in 3-6 months

why do lumbar precautions last longer

we need more stability for weight bearing

phase 1 of disc replacement rehab

initiate walking program, core activation

goals of phase 2 disc replacement rehab

pain control, increase lifting, re-establish neuromuscular control, ADLs

PT interventions during phase 2 of disc replacement rehab

flexibility/ROM, walking or bike, balance, core stabilization, ergonomic education for ADLs

goals of phase 3 of disc replacement rehab

pain free ROM, no instability, muscular endurance/strength, return to work

PT interventions during phase 3 of disc replacement rehab

controlled extension and rotation movements, balance, conditioning, functional/work-specific