biostatistician determined 20 subjects would be adequate to perform statistics

The most common forms of injection used for the treatment of degenerative lumbar spinal stenosis (DLSS) patients with neurogenic claudication (NC) are the caudal and inter-laminar epidural injections of anesthetic and steroid. Unilateral transforaminal epidural steroid injections (TESI) are also used to alleviate patients' symptoms of NC from DLSS, particularly in patients whose level of stenosis is L4-5 or higher. However, these unilateral injections do not cross the midline, so in cases of lower extremity pain and symptoms on both sides, a bilateral TESI would probably be more beneficial.

To date, there have not been any well designed prospective studies to determine the effectiveness of bilateral TESI below the level of stenosis in DLSS patients with NC. Therefore, the goal of this prospective, non-randomized case-series outcome study is to evaluate the effectiveness of BTESI in alleviating symptoms of NC, as well as improving function in patients with DLSS. The hypothesis is that BTESI at the level below the most stenotic segment of the central canal of the lumbar spine decreases symptoms of NC and improves function in patients with DLSS.

Inclusion Criteria:

• Symptoms of back/buttock/leg pain (NOT radicular pain) in a neurogenic claudicatory fashion, relieved by stooping or sitting down, for at least 3 months with no or poor response to conservative treatment (analgesics, NSAIDs, or physical therapy)
• Patients with bilateral buttock and/or bilateral lower extremity pain in a neurogenic fashion with or without lower back pain
• Radiologic documentation of degree of degenerative lumbar spinal stenosis (DLSS)
• MRI/CT showing at least moderate central canal spinal stenosis (neuro-radiologist definition) with symptoms correlating with stenosis (symptoms of back/buttock/leg pain without unilateral radicular pain in a neurogenic claudicatory fashion, relieved by stooping or sitting down)
• Patients choosing to receive BTESI as their next treatment option, following discussions with their spine doctor
• Patients who can give informed consent, could tolerate the procedure, and who are able to understand and answer the forms and questionnaires properly.

Exclusion Criteria:

• Radiologic spinal stenosis without symptoms of spinal stenosis
• Symptoms of neurogenic claudication without at least moderate degree of radiologic spinal stenosis
• Patients with specific lumbo-sacral radicular symptoms or radiculopathy (radicular pain secondary to a single nerve root compression/inflammation; usually follows a specific dermatome in lower extremities; unilateral radiculopathy either from disc herniation or lateral recess stenosis)
• Patients with vascular claudication (pain in the legs secondary to arterial insufficiency)
• Previous lumbo-sacral surgery
• Any condition that does not allow the patient to stand and/or walk for any length of time (e.g., COPD, severe lung disease, etc.)
• Patients with symptomatic hip joint pathology concurrent with spinal stenosis
• A coexisting musculoskeletal condition that would negate functional improvement from the injection (e.g., severe Parkinson disease, hemiparesis, etc.)
• Malignancy or infection to the spine
• Another pain generating condition that would mask the improvement provided by the injection
• Patients who had lumbar epidural steroid injections within the past six months
• Significant psychologic diagnosis and/or dementia
• Patients receiving workman's compensation benefit
• Patients unable to give consent on their own, or who are not able to understand and answer the forms and questionnaires, or their answers will not be reliable.

up to 6 months after injection