Knowing when not to manipulate matters more than technique, and the clinicians most at risk of getting it wrong are those who have only been taught the thrust.
Dr. Larry Smith, DC, APRN puts it directly: “we also have to know what not to do for them. Know when you're out over your skis.”
Cauda equina syndrome: the surgical emergency
This is the one that must be recognised immediately, and Smith describes it in terms that are hard to miss in a history.
Loss of bowel and bladder control. In his words, “patients wetting their pants, they can't control their bowel movements.”
Saddle paraesthesia — explained with an image worth keeping: numbness in “any part of the body that would touch a saddle while riding a horse,” essentially the entire groin, numb and non-functional.
Numbness or weakness in one or both legs, causing the patient to stumble and to struggle getting up from a chair.
The mechanism is compression severe enough that, as he puts it, the sacral plexus is damaged “to the point that the patient loses all control.”
His instruction is unambiguous: this is a surgical emergency — “get that patient away from you as quickly as possible.” Not a referral letter. Same day, emergency pathway.
Definitive motor weakness
The second absolute stop, and it is identified by watching the patient walk.
Smith's description: a patient “literally dragging one leg behind them” whose “foot slaps the floor” on walking. Test the deep tendon reflex and it is absent.
That combination means significant nerve compromise. “You can't treat that person. That patient needs to go out for MRI” — advanced imaging, not manipulation.
The distinction worth holding is between pain-limited weakness, where the patient can generate force but it hurts, and true motor loss with an absent reflex and a visible gait change. The second is a different problem.
Electric pain running down the leg
Smith characterises this precisely: pain shooting “proximal to distal from the upper part of the leg down to the foot. It feels like they're being shocked.”
Electric quality, travelling the full length of the limb to the foot, is nerve damage rather than referred mechanical pain. His view on where that patient belongs: “if you're going to do any good for them, get 'em to a surgeon.”
He applies the same threshold on imaging findings — where there is disc pathology on MRI with leg pain past the knee, the patient moves on to interventional pain or spinal surgery.
Note how this differs from ordinary leg pain. As he says elsewhere, “the word sciatica means nothing more than leg pain. It's as relevant to us as someone coming in with a cough.” Leg pain alone is not a red flag; electric pain to the foot with neurological signs is.
Severe osteoporosis
A straightforward mechanical risk: “severe osteoporosis, you can fracture bones.”
Smith's handling of this is notably honest about experience. His recommendation is to refer out — “don't keep them in your office” — while acknowledging that after 30 years he can treat an osteoporotic patient himself. His advice to anyone earlier in the curve: “when we're first starting to use these techniques, not a good idea.”
That is a more useful formulation than a blanket prohibition. The contraindication is partly relative and partly a function of the operator, and being clear-eyed about which side of that line you are on is the skill.
Pathology that presents as back pain
The category most easily missed, because the patient's complaint sounds entirely mechanical.
Smith's list: kidney infection, tumour, colon cancer, gynaecological cancers. “These pathologies can show up as low back pain.”
His instruction is to be a clinician before being a manipulator: “Be a clinician. Is it an infection? Treat it. If you have a patient with a kidney infection, you have a patient with a tumour, you know to send them out.”
And the sequence he recommends is worth adopting as a habit: figure out the cause; if there is something you can fix, fix it; then revisit the back pain at follow-up. Manipulating a kidney infection does not harm the kidney — it wastes the visit at which the infection could have been diagnosed.
The examination that finds all of this
None of these require imaging to suspect. Smith's position is that “proper history and physical exam are paramount” — get the right diagnosis and apply the right treatment, and you can help the patient.
A screening sequence that covers the above:
- Ask about bowel and bladder function directly. Patients do not volunteer it.
- Ask about saddle numbness in plain language.
- Watch them walk. A slapping foot or a dragged leg is visible before any test.
- Test deep tendon reflexes. An absent reflex changes the plan.
- Characterise the leg pain. Electric and to the foot is different from aching to the thigh.
- Ask what else is going on — fever, urinary symptoms, weight loss, bleeding, a cancer history.
- Consider bone quality in older patients and those on long-term steroid.
He is realistic about imaging for the ordinary case: x-rays can be helpful, but advanced imaging “is not gonna be medically necessary” for a simple sprain or strain, and generally will not be covered.
Where the threshold sits
The pattern across all of it is that manipulation suits mechanical problems in a stable spine, in a patient whose pathology you have understood. Smith's own indications are joint dysfunction of the lumbar and sacral spine, sacroiliac arthritis, facet syndrome and some disc lesions.
Anything with progressive neurological deficit, systemic illness, or structural fragility belongs somewhere else. Declining to treat is a clinical decision, not a failure — and it is the one that keeps the technique safe.
Learn blocks with your hands, not from a page
Empire’s Pain Management Training (THE Pain Show) is accredited for 25.25 AMA PRA Category 1 Credits™, jointly provided by AKH, Inc, and Empire Medical Training. For narrower peripheral work, Joint, Extremity and Non-Spinal Injection Training carries 6.75 credits for the complete in-person hybrid program, and Advanced Musculoskeletal Ultrasound Guided Injections builds the guidance skills above.
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