Parasagittal interlaminar epidural approach versus the transforaminal epidural approach for the treatment of lumbar radicular pain: a randomized, blinded, prospective outcome study. Presenter: Jason Lee, MD PGY-3 Department of Physical Medicine and Rehabilitation University of Kentucky

Researchers Jason Lee, MD Pravardhan Birthi, MD Jay Grider, DO, PhD

Departmental Affiliations Department of Interventional Pain Medicine, University of Kentucky Department of Physical Medicine and Rehabilitation, University of Kentucky

Background Lumbosacral radicular pain is characterized by pain radiating in one, or occasionally more than one, lumbar or sacral dermatomes Common condition Annual prevalence ranging from 9.9% to 25% (1) Development of radicular pain depends on both mechanical factors and concomitant nerve irritation by chemical mediators released from the disrupted disc (2)

Background The transforaminal epidural approach, by definition, results in application of steroid to the affected nerve resulting in greater specificity of treatment Results in spread of medication preferentially to the symptomatic side and along the nerve root Comparative studies have suggested better clinical efficacy for transforaminal techniques when compared to midline interlaminar applications of epidural steroids (5) Improved pain scores, improvement in activities of daily living, and decreased pain-related anxiety and depression(3)

Background Despite the tendency of the literature to suggest superiority of the transforaminal epidural route of administration of steroid, the technique does come with several potential complications. 1) Intravascular injection 2) Air emboli 3) Vascular trauma 4) Particulate emboli 5) Cerebral thrombosis 6) Epidural hematoma 7) Nerve root and/or spinal cord damage (6) By far the most devastating complication of this technique is the potential for spinal cord ischemia/vascular injury secondary to needle trauma or intravascular injection of particulate material

Background It is this copious vascular supply that presents the technical risk to the interventionalist The largest artery is the Arteria Radicularis Magna, also known as Artery of Adamkiewicz Present in the majority of patients in between T9 and L1 but can be found as high as T7 and low as L4 An equally important and potentially greater risk is damage or injection into the small segmental arteries which lie within the neuroforamen, ultimately resulting in segmental ischemia due to embolism (6, 7)

Vascular supply

Background Several techniques have been described for the transforaminal approach to the epidural space with the most commonly used technique taught as the “safe triangle” or supraneural approach (6) The safe triangle of the neuruoforamen descriptively is situated just lateral to the inferior margin of the pedicle, dorsal to vertebral body and cephalad to nerve root Despite being known as a “Safe Triangle”, studies demonstrate that perhaps reevaluation of the technique is warranted as the technique of choice.

“Safe triangle”

Background Interlaminar epidural steroid injections have been suggested to be less beneficial when compared to classic transforaminal approaches with regard to efficacy A recent novel parasagittal interlaminar technique has recently been proposed by Candido et al (9) Preliminary feasibility study Demonstrated that the parasagittal approach resulted in dye spread in lateral/foraminal epidural space Suggested that this approach could be highly effective in the application of steroid to the disc/nerve root interface in lateral recess of the spinal canal (9)

Objectives The central hypothesis: To determine the clinical effectiveness and safety of parasagittal interlaminar steroid injections when compared with classic transforaminal epidural steroid injections for Lumbosacral radicular pain.

Objectives Specific aim #1: To determine the effectiveness of parasagittal interlaminar steroid injections when compared with classic transforaminal epidural steroid injections for Lumbosacral radicular pain.   Specific aim #2: To determine the clinical safety of parasagittal interlaminar steroid injections when compared with classic transforaminal epidural steroid injections for Lumbosacral radicular pain. Specific aim #3: To evaluate functional status and difference in opioid use following parasagittal interlaminar steroid injections when compared with classic transforaminal epidural steroid injections for Lumbosacral radicular pain.

Study Design Prospective Randomized Double blinded Controlled trial

Study Design We will randomize 70 patients with the diagnosis of lumbosacral radicular pain to one of the following groups: 1) Parasagittal interlaminar steroid injections 2) Transforaminal epidural steroid injections We will randomize the patients using an experimental-design generator and randomizer program for simple random allocation into equal-sized groups Total participation will be approximately 12 weeks

Study Population Patients who are able to provide informed consent will be recruited from the Interventional Pain Associates clinic at the University of Kentucky Good Samaritan Hospital. They should have lumbar/sacral radicular pain based on history and physical examination findings.

Inclusion criteria >/= 18 years of age Patients who have failed conservative treatment for 12 weeks. Patients with clinically diagnosed pain lumbar radicular pain Pain of >4 on VAS scale. Pain episodes must occur at least weekly. Pain is not secondary to systemic inflammatory arthropathy. Pain that requires intermittent or ongoing treatment with narcotics. Aspirin for pain relief or for other indications is acceptable. Concurrent specified rescue pain medication allowed. Men, women, and minorities will be included in the study provided inclusion criteria are met. Patients who are on Coumadin are eligible for study provided they are off Coumadin for 7 days and INR < 1.5. Patients who are on Plavix or any other anticoagulant are eligible for study provided they are off anticoagulants for at least one week.

Exclusion criteria Severe, debilitating, or acute pain primarily originating from sources other than lumbosacral radicular pain. Women of childbearing age will not be excluded from the study, however pregnant women will be. History of cervical stenosis on magnetic resonance imaging (MRI) or computed tomography (CT). Infection at the intended site of injection. Medical condition that would preclude study participation. Allergies to lidocaine, bupivacaine, or steroids. Transforaminal steroid injection or interlaminar midline lumbar steroid injection procedure within 3 months. Non-English speaking subjects will also be excluded.

Informed Consent Process Each subject will receive a verbal and written explanation of the purposes, procedures, and potential risks of the study Once the subject and the principal investigator (PI) are in agreement, a signed consent form will be obtained Subjects will be free to withdraw from the study at any time This research is felt to have moderate risk

Research Procedures During week 0, initial visit: Subjects will have eligibility confirmed through history and physical exam Complete evaluations and questionnaires Subject will be randomized into one of the two study groups; will receive either lumbar transforaminal vs parasagittal interlaminar epidural steroid injections Estimated visit length: one day.

1 month follow up Subject will return to pain management clinic for follow-up evaluation, questionnaires Estimated visit length: one day.

3 month follow up Subject will return to the pain management clinic for follow-up evaluation, questionnaires, and pain diary submission for review Subjects then undergo a directed interim history and physical examination, complete questionnaires about pain including VAS scale and quality of life since the injection(s) The subject will be evaluated at that time by a physician who is unaware of which treatment/s the patient received for single blinded study Estimated visit length: one day.

Potential risks Reproductive risks: If you are pregnant, or think you may be pregnant, inform the study doctor prior to receiving treatment so that appropriate tests and precautions can be performed. These procedures involve fluoroscopy which can be harmful to a fetus. Clinical screening: You may feel uncomfortable being asked about your medical information including the medications you are taking.

Procedure risks Transforaminal steroid injection: Pain during &/or after the procedure, bleeding, bruising, infection, damage to surrounding structures such as bone/cartilage/muscle/ vessels/nerves, allergic reactions which can be life threatening if untreated, heart irregularities, dizziness or lightheadedness, death. Parasagittal interlaminar lumbar steroid injection: Pain during &/or after the procedure, bleeding, bruising, infection, damage to surrounding structures such as bone/cartilage/muscle/ vessels/nerves, allergic reactions which can be life threatening if untreated, heart irregularities, dizziness or lightheadedness, lung puncture, pneumothorax which can be life threatening, death.

Other Issues Addressed in the Protocol Safety precautions Benefit vs Risk Available alternative treatments Research materials, records, and privacy Confidentiality Payment Cost to subjects Data and safety monitoring Subject complaints Attachments: VAS, Quality of life questionnaire

References Koen Van Boxem MD, Jianguo Cheng MD, PhD, et al. Lumbosacral Radicular pain. Pain practice (2010),10,(4);pp339-358. Marshall LL, Trethewie ER. Chemical irritation of nerve root in prolapsed disc. Lancet (1973),2:p320. Thomas E, Cyteval C, Abiad L, et al: Efficacy of transforaminal versus interspinous corticosteroid injection in discal radicular—a prospective randomized, double-blind study. Clin Rheumatol (2003),22:pp299-304. Manchikanti L. Transforaminal lumbar epidural steroid injections. Pain Physician (2000), 3:pp374-398. Ackerman WE 3rd, Ahmad M. The efficacy of lumbar epidural steroid injections in patients with lumbar disc herniations. Anesth Analg. (2007) May;104(5):pp1217-22. Glaser SE, Shah RV. Root cause analysis of paraplegia following transforaminal epidural steroid injections: The “unsafe”triangle. Pain Physician (2010),13:pp237-244. Bogduck N. Lumbar spinal nerve blocks. In practice Guidelines for spinal Diagnostic and Treatment Procedures, 1st ed. International Spine Intervention Society (ISIS), San Francisco, (2004) :pp3-19. Lew HL,Coelho P,et al: Preganglionic approach to transforaminal epidural steroid injections. Am J Phys Med Rehabil (2004),83:p378. Candido KD, Raghavendra MS, et al: A prospective evaluation of iodinated contrast flow patterns with fluoroscopically guided lumbar epidural steroid injections: the lateral parasagittal interlaminar epidural approach versus the transforaminal epidural approach. Anesth Analg. (2008),106(2):pp638-44. Google images