Chapter 62: Interlaminar Epidural Steroid Injections Flashcards
What are the most common vertebral levels affected by spinal stenosis?
L4-5 in the lumbar spine and C5-6 in the cervical spine
What structures must the needle pass through during an interlaminar epidural steroid injection (ILESI)?
Skin, subcutaneous fat, supraspinous ligament, interspinous ligament, and ligamentum flavum.
What percentage of patients experience extraradural injection with blind epidural needle placement?
Up to 30%, even in the hands of experienced proceduralists
Why is the paramedian approach superior for cervical epidural steroid injections (ESI)?
The ligamentum flavum is more frequently observed with the paramedian approach, making it superior for cervical ESI.
ILESI is not recommended above what level?
C6-7, due to incomplete presence of LF and small epidural space
What is the median level of contrast spread for lumbar ILESI with 3-5 mL of injectate?
Approximately two vertebral levels.
A caudal ESI has been demonstrated to spread as high as what vertebral level?
L3
What steroids are most commonly used and best studied in epidural steroid injections (ESIs)?
Methylprednisolone and triamcinolone.
What is the common brand name of the following:
triamcinolone
methylprednisolone
dexamethasone
betamethasone
triamcinolone = Kenalog
methylprednisolone = Depo-medrol
dexamethasone = Decadron
betamethasone = Celestone
What is the therapeutic dose range for steroids in ESI?
Typically 40-80 mg, with no difference in effectiveness between these doses.
Why do the Multi-Society Pain Workgroup guidelines endorse depo-steroids for interlaminar ESI?
Large studies have shown greater effectiveness for depo-steroids compared to soluble dexamethasone.
What are the unique benefits/risks of the three main types of epidurals (interlaminar, caudal, transforaminal)?
Interlaminar: for unilateral or bilateral symptoms, higher volumes required for increased efficacy
Caudal: injection distant from target site, efficacy similar to ILESI, requires high volume, safe
Transforaminal: carries additional risk, more efficacious than ILESI/caudal, smaller volumes sufficient
A high concentration of ___ is present in intervertebral discs, which may explain the inflammation / pain with disc extrusion.
Arachidonic acid, an important substrate of the cyclooxygenase/lipoxygenase pathways responsible for inflammation and pain.
True or false: there is consensus regarding the efficacy of ESIs.
False. Despite, numerous high quality studies and meta analyses, there is no clear consensus given significant variability in findings.
Many studies suggest temporary benefit but no long-lasting pain relief or functional improvement.
Outbreaks of fungal meningitis occurred in 2002, 2012, and 2013 after ESI procedures for what reason?
Unsterile techniques during drug compounding, prior to delivery of the clinical site.
What is the incidence of vascular injection during cervical ILESI?
4.2%
What are the most serious potential complications of ILESI?
Infection
Epidural hematoma
Spinal cord trauma from needle placement
Arachnoiditis (intrathecal injection)
What are risk factors for development of epidural hematoma following ILESI?
Blood thinners/coagulation/platelet dysfunction
Traumatic needle placement
Large bore needle
Female gender
Inadvertent intradiscal injection is a complication associated with what ESI approach?
Transforaminal
Risk factors for post dural puncture headache.
Large bore needle
Cutting tip (as opposed to pencil point)
What are the pharmacologic-associated risks associated with ESIs?
Bone demineralization
HPA suppression (lasting 14d - 3mo)
Hyperglycemia
Immune suppression
Extra attention should be given to risks / benefits of ESI in patients with what comorbidities?
Post-menopausal women
Osteoporosis
Diabetics
Immunosuppressed patients
Despite better efficacy associated with TFESI, why is ILESI still the first line treatment in most cases?
TFESI carries additional, potentially catastrophic risks
