Several people on the list have talked about decalcification techniques in
clinical practice. Let me contribute experience of a small-laboratory
surgical pathologist laboring in his last years of practice under Managed
Care. In these circumstances we cannot hope for new technology, but we can
sometimes salvage old technology. In many of the small laboratories I work
in, decalcification skills are being lost.
As to turnaround time: I wish I knew what TAT large orthopedic specimens
(mostly hips and knees) require. If they need a surgical pathology report for
billing purposes, they need it in a bit less than a week.
If I receive a femoral head on Monday, I can slab it, fix the slabs
overnight, and decalcify a piece of a slab over another night - that means I
have slides Thursday morning. To take a day off of this, somebody has to move
the specimen from fixative to decalcifying solution late at night.
The elegant radiographic technique one of you described would be nice to
have, but I've seen an in-department radiographic unit (Faxitron) in exactly
one of perhaps forty surgical pathology labs I've worked in since residency.
If I had this technique, I'd use it, though I suspect its yield of clincally
useful information would be small. My normal special tools for slabbing heavy
bone are a dime-store hacksaw and a wad of paper towels - a Satterlee saw
(from Lipshaw) is usually many managers away.
For clinical purposes, gross diagnosis is often adequate for joint
replacement specimens done for osteoarthritis. The description and gross
diagnosis are simple once you know what to look for. The high school dropouts
who decide whether or not surgeons get paid are programmed to recognize the
following string: "eburnation and osteophyte formation consistent with end
stage osteoarthritis", and those exact words should appear in the diagnosis
Osteophytes are the mounds of cartilage and distorted bone that appear at the
edges of articular surfaces. Eburnation is the baring of bone (the word
originally meant "turning into ivory") by the erosive process. The point of a
knife will not enter an eburnated surface, as it will even the thinnest of
abraded articular cartilage. Eburnated surfaces are usually oval and often
I would describe such a specimen as "Received in formalin is 120 grams of
products of a total knee replacement, including an intact tibial plateau,
fragments of femoral condyles, loose osteophytes, menisci, and fatty
synovium. The condylar fragments show oval areas of grooved eburnated bare
bone as much as 30 mm wide, and smaller eburnated foci are present on the
tibial surface also. Osteophytes up to 10 mm wide surround the articular
surfaces. No sections are submitted." (Victoria Ryder, is this the question
you wanted an answer to?)
If the laboratory's ritual requires decalcified sections, I painfully slab
out sections of eburnated bone. Real men use an oscillating (Stryker) saw for
this purpose, but this technique is thoroughly unsafe, and would not be
permitted if people anybody gave a damn about were doing the gross
Fractured femoral heads need microscopic examination, because metastatic
cancer occasionally causes fractures ("pathologic fractures") and needs to be
identified. (Remember that the pathologist is working without the patient's
history.) Usually the osteoporotic bone is easy to slab with a hacksaw,
though some of them indeed are hand-hurters. If the service is well enough
managed that the pathologist or assistant is working entirely without the
patient's history, the 10 mm wide hemorrhagic fracture zone in the otherwise
dull yellow cancellous bone identifies a recent fracture.
Obviously I'm describing clinical techniques, not research. I prefer to do my
own decalcification, though many pathologists prefer to hand it to the
technologist. The important thing is to decide who's going to do it, so that
the decalcifying specimen doesn't go astray - and pathologists are notorious
for mislaying them.
Arthroscopic specimens need microscopic examination, though many pathologists
are required to gross-only these specimens. The diagnostic yield on
arthroscopic specimens is quite high, even though in a well run hospital it
is impossible for the pathologist to obtain clinical history or arthroscopic
findings. It's usually acceptable to avoid gross bone fragments in selecting
arthroscopic tissue for microscopic examination.
Gayle Callis mentions "For articular cartilage in osteoarthritic knees,
safranin O/Fast Green is commonly used, and toludine blue may also be
useful." The safranin O trichrome variant - basically it's in Lillie's 3rd
ed. - would be nice to have for arthroscopic material, but I have never seen
it. Gayle, are the complex techniques you describe designed for routine
clinical use, or for research purposes?
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