Introduction
Bone Marrow Concentrate (BMC), often referred to as Bone Marrow Aspirate Concentrate (BMAC), represents a significant advancement in orthobiologics. Unlike Platelet-Rich Plasma (PRP), which primarily utilizes platelets from peripheral blood, BMC harnesses the regenerative potential of the bone marrow niche.
The primary therapeutic agents in BMC are Mesenchymal Stem Cells (MSCs) and Hematopoietic Stem Cells (HSCs). However, the mechanism of action is not merely "cellular replacement." Current evidence suggests that MSCs function primarily through a paracrine effect—secreting bioactive factors, cytokines, and exosomes that modulate inflammation, prevent apoptosis, and stimulate local tissue repair in avascular or hypovascular zones (such as the intervertebral disc or the avascular zone of the meniscus).
2. Indications
For an interventional pain practice, the following conditions show the most promising response to BMC therapy:
Spine (Interventional targets)
- Discogenic Pain: Specifically for early-to-moderate Degenerative Disc Disease (Pfirrmann Grade II-IV) with intact annulus or small high-intensity zones (HIZ).
- Facet Joint Arthropathy: For patients refractory to radiofrequency ablation or those seeking tissue regeneration rather than neurolysis.
- Sacroiliac Joint Dysfunction: Chronic SI joint pain due to ligamentous laxity or early degeneration.
Knee
- Osteoarthritis (Kellgren-Lawrence Grades 2-3): Best for patients with some remaining cartilage who wish to delay arthroplasty.
- Meniscal Tears: Specifically non-obstructive tears in the "red-white" zone where blood supply is poor.
- Osteochondral Defects: Focal cartilage defects.
Shoulder
- Rotator Cuff Tears: Partial-thickness tears or interstitial tears (PASTA lesions).
- Glenohumeral Osteoarthritis: Early-stage arthritis.
- Labral Tears (SLAP lesions): As a conservative biological augmentation to physical therapy.
3. The Procedure: Harvesting, Processing, and Implantation
Note: This procedure should always be performed under strict aseptic conditions, ideally in an operation theater or a clean procedure room.
Phase 1: Harvesting (The "Gold Mine")
The most cellularly dense marrow is found in the Posterior Superior Iliac Spine (PSIS).
- Positioning: Patient is prone.
- Anesthesia: Local infiltration of lidocaine (skin and periosteum). Conscious sedation may be used for patient comfort.
- Aspiration: A Jamshidi needle or specialized bone marrow trocar is advanced into the PSIS.
- Technique Tip: To maximize MSC yield and minimize peripheral blood dilution, aspirate in small aliquots (5-10ml) from different depths and angles within the ilium.
- Volume: Typically, 60ml of bone marrow aspirate (BMA) is harvested to produce 6-7ml of BMC.
Phase 2: Processing
The aspirate is processed using a specialized centrifugation system.
- Separation: The centrifuge separates the aspirate into three layers: red blood cells (bottom), the "Buffy Coat" (middle layer containing stem cells and platelets), and platelet-poor plasma (top).
- Concentration: The Buffy Coat is extracted. This 6-7ml concentrate contains 5-10 times the baseline concentration of stem cells and growth factors.
Phase 3: Implantation (Interventional Precision)
Blind injections are not recommended for BMC.
- Spine: Fluoroscopic (C-arm) guidance is mandatory for intradiscal or facet injections to ensure safety and precision.
- Joints: High-resolution musculoskeletal ultrasound is preferred to ensure the BMC is delivered intra-articularly or directly into the tendon tear/defect.
4. Patient Instructions
Pre-Procedure Protocol
- NSAIDs: Discontinue all anti-inflammatory medications (Ibuprofen, Naproxen, Diclofenac) for 7 days prior to the procedure. These drugs inhibit the platelet release reaction required for the healing cascade.
- Hydration: Drink plenty of water (2-3 liters) daily for 48 hours before the procedure to facilitate easier marrow aspiration.
- Blood Thinners: Consult with a cardiologist regarding the temporary cessation of anticoagulants/antiplatelets.
- Alcohol/Smoking: Avoid for at least 1 week prior to improve cellular health.
Post-Procedure Protocol
- Immediate (0-48 hours): Relative rest. Ice may be applied to the harvest site (hip) for soreness. Do not use heat.
- Medication: Strictly avoid NSAIDs for at least 4-6 weeks. Pain should be managed with Acetaminophen (Paracetamol) or mild opioids (Tramadol) if necessary.
- Activity:
- Spine: Avoid heavy lifting, twisting, or high-impact activities for 2 weeks.
- Knee/Shoulder: Partial weight-bearing or sling use may be recommended for 3-7 days depending on the specific injection site.
- Rehabilitation: Physical therapy should commence 2 weeks post-procedure, focusing on eccentric strengthening and range of motion.
