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Spinal Manipulative Therapy: Part 2
In the last column, I discussed our (physical therapists) seemingly lack of need to retain spinal manipulation as part of our scope of practice. I am going to take the stance that informed physical therapists will not easily give up any part of our practice regardless of whether it is a particular area or technique in pediatrics, cardiopulmonary, neurology or even orthopedic care. Given this the current column will discuss safety issues in spinal manipulative therapy (SMT).
The Risk The risks are well documented. Vertebral artery accidents (VBA) leads the list accounting for about 70% of all damage caused by SMT. Following VBA, cauda equina syndrome/ disc prolapse and disc syndrome aggravation make up about 20% of injuries. The remainder are miscellaneous complications including fractures, nerve compression, hemorrhage, cerebral infarcts etc. The incidence of serious accidents varies with the study read. In a literature review through 1993 of all reported cases of spinal manipulation, Assendelft et al (J Family Pract 42(5):475-480 1996) found 295 cases of complications divided as follows:
The average age of the VBA patient was 38. The cerebral incidents occurred mainly in the older patient who usually had a pre-existing condition that was not diagnosed. Disc herniation occurred in 56 cases in the lumbar spine with CES usually showing as a progression. Disc herniation occurred 4 times in the cervical spine and once in the thoracic. 49% of the lumbar disc enlargement occurred during MUGA and all cases resulted in surgery. In a survey of Danish chiropractors, Klougart (J Manip Physiol Ther 19(6): 371-377) 1996) found one complication for every 1.3 million cervical treatment sessions, one for every 0.9 million upper cervical sessions and one in 400 thousand if rotation was used in the upper cervical spine. From this, rotational techniques in the upper spine are four times more likely to produce VBA than non-rotational. Rotation techniques in the lower spine were 2 almost 2.5 times more likely to produce VBA than non-rotational. The report all but recommended that rotational techniques should not be first choice in the upper spine. A three year study (Livingston, MCP. Clin Orthop Rel Res 81:82-86 1971) gave an injury rate of almost 7% from 172 who received SMT. However, when you read the few case studies from this "study", it becomes apparent that the author's definition of an injury is somewhat different from elsewhere in the world. These "injuries" included:
A review of the literature and comparisons to the use of NSAIDs for cervical pain (Dabbs, V. et al. J Manual Physiol Therapeutics 18(8):530-536 1995) shows a very low risk of injury to the artery indeed much lower than the risk of taking NSAIDs for the same problem.
Mortality rate 23%. Recover with minimal or no after effects 33%. With 10-15 sessions of manipulation per year and 1 VBA in 1 million one patient in 100,000 will have an accident of which 1/4 will die. Therefore estimated death rate per course of treatment is 0.00025% 160 times less frequent than the NSAIDs death rate. If the higher figure of 1:500,000, then one patient in 50,000 will have an accident with a death rate of 0.0005% up to 80 less frequent than the NSAIDs death rate. The injury rate for manipulation is 80-400 less than GI problems.
NSAID Risk The common NSAIDs make up 5% of all prescription and over the counter drugs with about 90 million prescriptions annually and an unknown number of non-prescriptions. Their most serious complications are GI ulcers and hemorrhage. Estimate is that chance of gastric ulcer is 10-20% among NSAID users 5-10 times higher than in the general population.
The numbers concerning cauda equina syndrome as a result of SMT are not as well documented. One review of the literature found only ten cases of cauda equina syndrome caused by SMT reported between 1911 and 1989 (Haldeman, S. Spine 1992 17:1469-73 1992). Another review (Assendelft et al J Family Pract 42(5):475-480 1996) found 56 cases of either cauda equina syndrome or lumbar disc herniation following SMT. The extreme rarity of these conditions is surprising given the paucity of blood flow to the cauda equina. These radicular arteries are not large and the anterior and posterior spinal arteries suffer from any anomalies present in the vertebral arteries. It is possible that it is relatively easy to avoid manipulating a patient who is vulnerable to disc prolapse of the degree required to cause CES because of the obvious signs and symptoms present. One review and analysis of 138 cases in the literature (Powell FC et al: Neurosurg 33:1 1993 73-78) identified six risk factors:
Kleynhans and Terrett (In Aspects of Manipulative Therapy 2nd Edition. Glasgow, Twomey & Scull Eds. Churchill Livingston, Melbourne 1985) divided the causes of complications from SMT into practitioner related and patient related.
Practitioner Related
Caused by lack of knowledge of by lack of sufficient knowledge of anatomy, physiology, function, pathology, clinical presentation and failure to obtain objective test results. Excessive force or an inability to recognize warning signs is a frequent accompaniment of inexperience. However, most inexperienced manipulative therapists are reticent about performing SMT and if anything are usually overcautious. It is the experienced heavy handed, unthinking clod who is capable of doing damage. The medical history of the patient together with their drugs (anticoagulants and systemic corticosteroid used come to mind) must be ascertained. If it cannot be obtained from the patient, then the physician must share the information.
Patient Related
Patient's with psychological intolerance to pain or discomfort. Emotionally unstable patients who display vascular reactivity such as vasovagal effects are another source of complications. Dizziness caused by head movements that can be confused with VBI. Patients with excessive pain response for any reason. Patients who have painful movements in all directions. Congenital anomalies that are visible on X-ray may in and of themselves restrict the use of SMT. However, they are also indications of variations that are not obvious. A cervical rib or syndactyl could indicate vertebral artery hypoplasia as examples. Pathology potentially causing such conditions as VBI from osteophytosis for example and the association of cervical arthrosis (4/14 cases) with vertebrobasilar infarction. Narrowing of the spinal canal may also increase the vulnerability of the spinal cord to SMT. Certain systemic arthritides such as RA, AS, Reiter's and psoriatic arthritis may all decrease the strength of the transverse ligament or the bone leading to rupture or fracture. Bone cancer will decrease the strength of the bone leaving open the possibility of fracture. Anticoagulant therapy, particulary heparin is a problem. The risk of intraspinal bleeding is coupled with the risk of fracture for heparin induced osteoporosis. A or microdensia, Down's syndrome, system inflammatory arthritis, Grissel's syndrome, corticosteroid therapy, children under twelve years and trauma all predispose this region to severe injury to the cord, lower medulla or vertebral artery if SMT is carried out. A careful history, examination and if indicated open mouth and kinetic craniovertebral radiographs help reduce the risk. The failure to recognize that bilateral signs and leg symptoms particularly if they are radicular and multisegmental are either established or embryonic cauda equina syndrome is inexcusable. We can see from the above that while the consequences of VBA may be severe, they are very rare. It is far safer to receive a course of manipulative treatments for neck pain than it is to take aspirin for the same pain. On the other hand, the examination of the patient, the selection of the technique and the ongoing evaluation of the patient's neurological status are vital components in the safe, effective and efficient application of SMT.
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