Chronic Pain and Falls
Falls are a frequent occurrence among patients with chronic pain, especially low back pain. I first observed this phenomenon in the mid-90s, early in my practice that eventually consisted of several hundred people with chronic pain.
The population consisted predominantly of lower back pain patients, who entered my practice with an average duration of pain of 2 years, on average. Many of these patients stayed with me throughout my career, and at the time I retired, the average duration of the patients in my practice was 15 years.
More than half of patients reported sudden falls without any warning or obvious environmental precipitating factor.1-3 Most frequently the patient described the event as, “It was as if the leg just wasn’t there,” or less frequently, “It was like I was thrown backwards.” The falls seemed to occur without normal “protective reflexes.”
This led me to explore the biomechanics of movement and how the diseased spine and hips may impair movement in this vulnerable population. The following is a review of my experience over 20 years of pain practice.
The Scope of the Problem
No one really knows the true incidence of falls among pain patients, primarily because many falls go unreported. However, Stubbs et al conducted a meta-analysis of more than 1,330 articles on falls in older adults. They found that “community-dwelling older adults with pain were more likely to have fallen in the past 12 months and to fall again in the future. Foot and chronic pain were particularly strong risk factors for falls, and clinicians should routinely inquire about these [symptoms] when completing falls risk assessments.”4
Leveille has published extensively on the epidemiology of falls, especially as it relates to the elderly and women living in the community.5,6 She documented that community dwelling women with pain fall more frequently than women without pain. In one study, she demonstrated that the use of at least 1 pain medication, without specifying dose or brand, provided some protection against falls in patients with chronic pain. However, another study showed that there was no correlation between use of medication and falls. The implication, I believe, is clear: medications are not a major contributor to the increased risk of falling in people with chronic pain.
My own experience mirrors these findings albeit in a much younger population, with average age in the 40 to 50 year old range consisting predominately of injured workers. Patients also report that they are never asked about falls and/or that they were too embarrassed to discuss the issue, often feeling embarrassed by their “clumsiness.” However, there was rarely a day in my office without at least one patient reporting a new fall during the past month.7
The observed falls are not benign in nature, with frequent injuries including fractures at various sites, avulsed teeth, superficial and deep tissue (muscle, kidney) contusions, and lacerations and abrasions. Rubenstein et al reported that patients 65 years of age and older account for 75% of all death caused by fall. About 40% in this age group fall at least once a year, and 1 in 40 of them ends up in the hospital. Only half of hospitalized fall patients are alive one year later.8
In my practice, a review of records documenting superficial injuries revealed a random distribution of injuries from head to foot: 15 head injuries, 15 trunk injuries, and 14.5 injuries per limb.3 This included one woman who avulsed the tip of a finger pad when she fell breaking a glass she was holding; 2 men in their 30’s with no evidence of osteoporosis who suffered proximal fractures of the tibia and fibula after a fall; and several patients who fell in areas of high traffic—one with fatal injuries. Table 1 illustrates 4 examples of typical fall patients in my practice.
Risk of Falls
Several factors account for the risk of falls among chronic pain patients, including osteoporosis, age-related physiological changes, sensory losses, medication side effects, and loss of biomechanical movement.
Over the years, I have tried to synthesize seemingly disparate events and information to develop a proposed model of the intrinsic factors that increase the risk of falling in people with pain. Note that falls that have clearly been triggered by external obstacles or events have been excluded. The information has been gleaned from the following:
- The nature of injuries that are suffered and the patterns of their distribution.
- Reflex parameters as measured in the clinical examination.
- Electrodiagnostic studies focused on reflex events that can also be measured relatively easily, although more advanced electrodiagnostic techniques may be required.
- Patient reports of the events that occur immediately prior to, during, and immediately after loss of control of their antigravity motion.
- Review of the literature.
- Principles of physics, including dynamic and static momentum mechanics and biomechanics.
Over a one-week period in my clinic, 57% of patients seen had reported at least one fall since the onset of their pain.1 I have also observed brisk patellar reflexes among patients with chronic pain.7 Reflex testing is performed with a “Queensquare pattern reflex hammer” with the patient sitting with feet placed flat on the floor. This position places the leg in a consistent position from one exam to the next and from one patient to the next. The examiner’s thumb is placed on the infrapatellar tendon and the thumb is struck with the weighted head of the reflex hammer. The pendulum motion of the hammer provides a reproducible rapid stretch of the infrapatellar tendon.
Using this technique, it is possible to elicit reflexes in almost all patients. Patellar reflexes in many patients with chronic pain are also often accompanied by a crossed adductor reflex.7 In fact, 44 of 100 (44%) chronic pain patients seen in 1 month demonstrated the presence of a crossed abductor reflex using this technique. I did not have a true control population, but in most people without chronic pain, I have not been able to elicit the cross adductor reflex, which is generally considered to be a pathologic reflex.
An extensive review of reflex phenomenon as measured with electrodiagnostic techniques by Courthey et al9 has shown that flexor withdrawal reflexes can be triggered by both nociceptive and mechanoreceptors. Various measurable parameters, including delayed latency responses of electrical events, are discussed, citing multiple studies. Researchers have proposed that measurements of some of the delayed latency responses may actually be a marker for chronic pain.10 Babiy et al has also reported a case in which the patient suffered an isolated instance of “asterixis,” which led to a fall in a patient taking gabapentin.11