Soreness after manipulation is common, and usually briefStrong evidence
Studies in different countries agree. In 1,058 new patients of Norwegian chiropractors, 55% reported at least one reaction over up to six treatments, mostly local discomfort, a headache, tiredness or discomfort spreading elsewhere, nearly all mild or moderate, and "Sixty-four percent of reactions appeared within 4 hours of treatment, and 74% had disappeared within 24 hours". In 465 Belgian patients at a first visit to manipulative therapists, 60.9% had a reaction, and in Swedish chiropractic patients reactions were "usually gone the day after treatment". A review of manual therapy by regulated therapists found minor or moderate short-lived reactions in about 41% of patients in cohort studies and 22% in trials.
In recent North American practice, 21.3% of visits followed up 2 to 7 days later had a new or worse symptom, whether or not the treatment caused it, most rated mild or moderate by the patients themselves. The US National Center for Complementary and Integrative Health (NCCIH) says "Most of these side effects go away within 24 hours". For osteopathy, the General Osteopathic Council (GOsC) says "it is not unusual to sometimes feel sore in the first 24 to 48 hours after treatment".
Sources 1, 2, 3, 4, 5, 6, 7
Part of it is the back's own ups and downsEmerging evidence
In a blinded trial of 183 adults with spinal pain, 42% given usual chiropractic care and 33% given a sham treatment reported at least one adverse event, a difference that wasn't significant, and the authors concluded that "A substantial proportion of adverse events after chiropractic treatment may result from natural history variation and nonspecific effects".
Reactions are commoner at the start of a course and were reported more by women and by people with long-lasting problems. Feeling worse straight away is less common: after US osteopathic treatment, patients felt worse or much worse at 2.5% of visits before they left. UK osteopathy patients said that whether soreness felt worrying depended partly on whether they had been told to expect it. In older adults, soreness and stiffness were common and no catastrophic events were found in the studies reviewed.
Sources 8, 9, 10, 3, 2, 11
The mid back and ribs, and thin bonesEmerging evidence
Manipulation of the upper back can leave the ribs and the muscles between the shoulder blades sore for a day or two (our reading of the reaction studies). Rarely, a rib breaks: in 960,140 sessions at 30 clinics in Hong Kong, the 2 severe events found were broken ribs in women over 60 with osteoporosis, and a Canadian case series describes 3 rib fractures after manipulation in patients aged 57 to 77, two with thinning bones.
A case series describes four people found to have spine fractures after chiropractic adjustments, and its authors advise that people with osteoporosis who have had a fall or injury have an X-ray before treatment. In more than a million older US adults who saw a chiropractor, injury within a week was rarer than after a GP visit (40 against 153 per 100,000), but more likely with osteoporosis, a clotting problem, inflammatory spine disease or long-term anticoagulants.
Sources 12, 13, 14, 15
Discs and nerves: rare, and no more common than after other careEmerging evidence
Case reports describe a disc herniation getting worse, or cauda equina syndrome, after low back manipulation: a review found 77 published cases worldwide, and "The anecdotal nature of these cases does not allow for causal inferences between SMT and the events identified in this review" (SMT is spinal manipulation).
Large record studies point to the back problem rather than the treatment. In 67,220 matched pairs of adults with low back pain, cauda equina syndrome within 3 months affected 0.07% after chiropractic manipulation and 0.11% after a physiotherapy assessment, and the authors conclude that people with back pain "may have an elevated risk of CES independent of treatment" (CES is cauda equina syndrome); the same held in people with a disc problem or sciatica. People who needed early surgery for a slipped disc were as likely to have seen a GP as a chiropractor beforehand, which the authors explain as back pain from a developing disc problem sending people for care. A much-quoted estimate puts the risk of manipulation worsening a slipped disc or causing cauda equina syndrome at less than 1 in 3.7 million, but that figure was calculated from published reports, not measured. A Chinese surgical series describes 10 people with long-standing disc trouble whose leg pain got sharply worse within 24 hours of manipulation. Whatever the cause, new leg weakness or numbness, or bladder or bowel changes, need urgent care.
Sources 16, 17, 18, 19, 20, 21, 22
If your neck was treated tooMixed evidence
Mild neck soreness or a headache after neck treatment is common: in a US trial of chiropractic care for neck pain, a quarter of people had more neck pain or stiffness; in 529 Dutch patients with neck pain, 56% reported a reaction after one of their first three treatments, 13% severe in intensity but none serious; and a UK survey of 50,276 neck manipulations found no serious events.
A rare stroke from a torn neck artery has been linked with neck manipulation in case reports. In Ontario, people under 45 who had this stroke were about three times as likely to have seen a chiropractor beforehand, and also a GP; the authors explain this as people with a tear already under way seeking care for neck pain and headache, and found no excess risk with chiropractic care compared with GP care (a 2010 erratum to this study exists, which we couldn't read). The American Heart Association says it is unclear whether the link reflects tears already present or the treatment, and that patients should be told about it before neck manipulation (a correction to its statement exists, which we couldn't read).
Later studies agree: no excess risk of carotid stroke after chiropractic care, none in older adults on Medicare, and, in 431,492 matched pairs of adults with new neck pain or headache, 31 neck artery tears in the 30 days after chiropractic neck manipulation (0.007%) against 58 after an ibuprofen prescription (0.013%). A review from outside the profession found "no convincing evidence to support a causal link". Serious events reported after neck treatment are nearly all after manipulation rather than gentler mobilisation, and no screening test reliably picks out who is at risk.
Sources 23, 24, 25, 26, 27, 28, 29, 30, 31, 32
Serious harm overall: rareStrong evidence
A scoping review by the Royal College of Chiropractors found that "benign adverse events following manual treatments to the spine are common, while serious adverse events are rare", with estimates ranging from 1 per 2 million manipulations to 13 per 10,000 patients. The NCCIH says serious problems "are very rare, and there are no accurate estimates of how often they occur". The GCC says "Chiropractic treatment is safe when performed correctly by a trained and registered chiropractor", that "It is common to experience mild to moderate aches and pains, stiffness and tiredness", that these "are usually mild and generally pass within a few days", and that "More serious side effects are rare but have occasionally been reported following spine manipulation".
Sources 33, 6, 34
When it isn't the adjustment: the causes the warning signs cover
Back pain can have causes no treatment created: cauda equina syndrome, a broken bone, infection, a burst aortic aneurysm and cancer are rare. The NHS asks for a 999 call for numbness around the genitals or bottom or new bladder or bowel changes, and a same-day check for back pain with a fever or feeling unwell. A swollen, throbbing calf can be a deep vein thrombosis (DVT), and sudden breathlessness or chest pain can be a clot in the lungs; a broken rib with breathlessness or tummy pain needs 999, and on blood thinners, severe bruising or sudden severe back pain can be a sign of bleeding, the NHS says.
With osteoporosis, the NHS says, a cough or sneeze can sometimes break a rib or partly collapse one of the bones of the spine. From 50, past the menopause or on long-term steroid tablets, sudden back pain after little force can be a spinal fracture from thin bones: NICE's osteoporosis guideline covers finding these fractures, and an NHS trust says that very occasionally a piece of broken bone presses on the nerves, so new leg weakness needs to be seen urgently.
Sources 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45
When a scan helps, and how it usually goesStrong evidence
Not for soreness after an adjustment. NICE says "Do not routinely offer imaging in a non-specialist setting" for low back pain, the GCC says "In most cases of non-traumatic musculoskeletal low back pain, an x-ray is not necessary", and disc wear on scans is common in people with no back pain (37% at 20, 96% at 80). Scans matter for the warning signs: an emergency MRI (magnetic resonance imaging) scan for suspected cauda equina syndrome, and an X-ray for a suspected broken spine bone or rib in thin bones. A scan can't show a misalignment that manipulation corrects.
Most reactions start within 4 hours and three quarters have gone within 24. If the back pain itself flared, new back pain improves most in the first 6 weeks: in 33 groups of 11,166 people, average pain fell from 52 out of 100 to 23 by 6 weeks. The GCC says that if you haven't improved within a few weeks of starting treatment, your chiropractor should discuss other options or refer you. No one can promise a date.
Sources 46, 34, 47, 1, 48
