It is what laboratories use to grow human cells.

PLATELET LYSATE

It is what laboratories use to grow human cells, and it is the only preparation here we are willing to put next to a nerve. Neither of those is a small claim.

The credential nobody mentions

Before platelet lysate was an injection it was a growth medium. Laboratories culturing human mesenchymal stromal cells need a supplement dense enough in growth factors to keep those cells dividing, and human platelet lysate has largely displaced fetal bovine serum for that job — on performance, not price.

That is a more demanding test than most orthobiologics ever face. A preparation that reliably expands human cells in culture is a preparation with a documented, potent and reproducible growth-factor profile. The literature calls it a potent and overlooked orthobiologic, and overlooked is the right word: it is used constantly in cell manufacturing and rarely discussed in clinics.

What it is, and the one thing that changes

Take platelets and break them open deliberately — usually by freeze-thaw — then remove the membranes and debris. What remains is a clear, acellular solution saturated with the same growth factors PRP contains: PDGF, TGF-β, VEGF, IGF and the rest of the secretome.

The difference from PRP is not concentration. It is state. PRP delivers intact platelets that must survive, adhere and degranulate in situ to release anything. Lysate delivers the released contents directly. Nothing has to work correctly after the needle comes out.

Two consequences follow, and both matter clinically. The growth factors are immediately bioavailable rather than dependent on cells behaving as intended in hostile tissue. And the product is acellular — no platelets, no red cells, and critically no leukocytes at all, which is a different proposition from even a leukocyte-poor preparation. It is also thinner, which decides where it can go.

Why that makes it the right choice near a nerve

This is the core of it. An irritated nerve root sits in a confined space and does not tolerate the things a joint shrugs off. A granular, cellular preparation placed against neural tissue is the wrong physical object in the wrong place — you are introducing particulate matter and an inflammatory cell load into a compartment where swelling itself is the problem.

Lysate answers both objections. Being acellular, it contributes no neutrophils and no cellular debris. Being low in viscosity, it spreads through tissue planes rather than sitting as a bolus, which is what you want when the intention is to hydrodissect — to separate a nerve from the tissue adhering to and tethering it — while delivering the biology at the same time.

That combination is why it is used here for perineural and epidural work, and why standard PRP is not. It is not a lesser version of PRP. For this target it is the more appropriate preparation, and the reasoning is the same one that governs the leukocyte-rich and leukocyte-poor distinction — match the preparation to the tissue rather than to the marketing.

Where the evidence stands, and how to read it

The clinical literature is smaller than PRP’s, and this page will not inflate it. A systematic review of preclinical and clinical studies in osteoarthritis found lysate a credible candidate with encouraging signals and small trials behind them. Broader reviews describe it as a promising regenerative candidate across wound healing, tendon regeneration, ocular surface disease and nerve repair.

The right way to read that is not “unproven, therefore weak”. It is that lysate has been developed principally as a manufacturing input, where the commercial incentive to run large clinical trials has never existed. Nobody owns it. There is no device company whose margin depends on proving it in a phase III program. The absence of large trials reflects the absence of a sponsor rather than a record of failure — which is precisely the pattern set out on why the trials disagree.

Meanwhile the mechanistic case is unusually solid, because the product is used at industrial scale on the strength of exactly the property being claimed for it.

Where we use it

• Perineural injection where an irritated nerve is the target rather than the joint it passes.
• Hydrodissection, to free a tethered nerve from surrounding tissue while delivering growth factors into the plane.
• Epidural and foraminal work, where a cellular preparation is not appropriate — relevant to the picture on PRP for a herniated disc.
• Alongside spinal work where the pain generator has been confirmed, under the rule set out on the spine and sacroiliac joint: nothing is injected until a block has told us the level is right.

What it will not do

It does not decompress a nerve. If a disc fragment or bony stenosis is physically pressing on a root, no injectate resolves that, and progressive weakness needs a surgical opinion rather than a biologic — promptly. It is not a substitute for the loading and behavioral work either, and it is not a stem cell treatment; there are no cells in it at all, which is rather the point.

What the appointment involves

Blood is drawn and processed at the same visit. The injection is placed under ultrasound or fluoroscopic guidance without exception — perineural work by landmark is not a technique, it is a hope. Volume is chosen deliberately: for hydrodissection you need enough to open a plane, which is a different calculation from filling a joint. The recovery timeline applies, and the post-injection course is generally milder than a leukocyte-rich tendon injection.

What people ask about lysate

Is lysate weaker than PRP?

No — differently prepared. The growth factors are already released rather than waiting inside platelets that have to degranulate where they land. For a target where you do not want cells, having the contents without the container is the advantage, not a compromise.

Why not just use PRP near the nerve?

Because standard PRP is cellular and granular, and a nerve in a confined space tolerates neither well. The leukocyte load is the specific objection, and lysate removes it entirely rather than reducing it.

Is there less evidence for it?

Fewer clinical trials, yes, and we would rather say so. It is worth knowing why: lysate is unpatented and unsponsored, and it earned its reputation in cell manufacturing where it is validated continuously against a demanding standard.

Does it hurt more or less?

Generally less than a leukocyte-rich tendon injection. The preparation is acellular and the deliberate inflammatory component is absent, so the post-injection course tends to be quieter.

Related reading

• Leukocyte-rich and leukocyte-poor PRP
• PRP for a herniated or bulging disc
• Spine and the sacroiliac joint
• Why the trials disagree
• How PRP works
• Risks and side effects