From decades of clinical practice and laboratory study, Russell knew that extreme motions of the head and neck could wound these remarkable arteries, producing clots, swelling, constriction, and havoc downstream in the brain. The victims could be quite young. His ultimate worry centered on the basilar artery. Located just inside the foramen magnum, the vessel arises from the union of the two vertebral arteries and forms a wide conduit at the base of the brain that feeds such structures as the pons (which plays a role in respiration), the cerebellum (which coordinates the muscles), the occipital lobe of the outer brain (which turns eye impulses into images), and the thalamus (which relays sensory messages to the outer brain and the hypothalamus and its vigilance area). In short, the basilar artery nourishes some of the brain’s most important areas. Russell worried that clots and cutoffs of blood in the vertebral arteries would impair the work of the basilar artery and its downstream branches deep inside the brain.
The drop in blood flow was known to produce a variety of strokes. Symptoms might include coma, eye problems, vomiting, breathing trouble, arm and leg weakness, and sudden falls—but by definition had little to do with language and conscious thinking. However, because strokes of the rear brain can severely damage the regulatory machinery that governs life basics, they can also result in collapse and death. Even so, the vast majority of patients survive the attack and go on to recover most functions. Unfortunately, in some cases, headaches can persist for years, along with such residual troubles as imbalance, dizziness, and difficulty in making fine movements.
The medical world of Russell’s day worried about these kinds of strokes, including a prominent type that began in circumstances that seemed quite innocuous. At beauty salons, during shampooing, women at times would have their necks tipped too far back over the edge of a sink, reducing the flow of blood through the vertebral and basilar arteries. The risk was judged especially great among the elderly. With aging, the vertebral arteries can lose their elasticity and narrow, and the normally smooth neck bones can grow spurs. When the neck bends far backward, the bony spurs can compress or otherwise harm vessels already narrow and inelastic. In addition, the stagnant blood can turn into a small factory of clot production. When the neck returns to a more normal position and the flow of blood resumes, the clots can travel down the arteries, heading deeper into the brain before settling in a narrow vessel and blocking its flow. A small epidemic of strokes resulted in a diagnosis known as the beauty-parlor syndrome.
Russell warned of yoga dangers in the pages of the British Medical Journal, a mainstay of the field established in 1840, just as Paul was finishing medical school in Calcutta. He drew parallels between yoga and such recognized threats as the beauty-parlor syndrome, noting that some poses produce “extreme degrees of neck flexion and extension and rotation.” He specifically cited the Shoulder Stand and the Cobra, displaying a good understanding of the field. In the Cobra, or Bhujangasana, “serpent” in Sanskrit, a student lies facedown and slowly rises off the floor, pushing the trunk upward with the arms and extending the head and spine backward. Iyengar, in Light on Yoga, suggests that the head should arch “as far back as possible.” Photos show him doing just that, his head thrown back on a trajectory toward his buttocks—in other words, the kind of maneuver that Russell found worrisome.
Cobra, Bhujangasana
In the Shoulder Stand, the neck is bent in exactly the opposite direction, going far forward, with the chin deep in the chest, the trunk and head forming a right angle. “The body should be in one straight line,” Iyengar emphasized, “perpendicular to the floor.” Ever the enthusiast, he called the pose “one of the greatest boons conferred on humanity by our ancient sages.”
Where Iyengar saw benefits, Russell saw danger. The postures, he said, “must for some people be hazardous.” His choice of the word “must” betrayed the speculative nature of his worry—but one grounded in a lifetime of experience. Russell warned that the basilar artery syndrome could strike practitioners of yoga and went on to cite a shadowy complication—doctors might have a hard time discerning its origin. The cerebral damage, he wrote, “may be delayed perhaps to appear during the night following, and this delay of some hours distracts attention from the earlier precipitating factor, especially when there is a catastrophic stroke.” In that case, of course, the deceased could give no account of prior activities.
His caution went to the inherent difficulty of understanding the cause of invisible brain injuries. We typically think of illness as focused on a particular body part—such as the heart or lungs. But the origins of strokes often lie relatively far away from where they hit, starting in the wilds of the bloodstream and ending in the brain. The gap, moreover, could involve not only distance but time—hours and sometimes days—as a clot worked its way downstream or as a damaged artery slowly became swollen and gradually reduced the flow of blood. Such complicating factors meant that, for a large percentage of strokes, physicians could discover no obvious explanation. Their medical term for such injuries was cryptogenic, meaning their origin remained a mystery.
That kind of uncertainty had long obscured the cause and the extent of the beauty-parlor syndrome. In essence, Russell was now asking if the same thing was happening with yoga.
His alert proved timely. Perhaps he was simply ahead of his day, or perhaps his warning opened the eyes of colleagues, or perhaps the growth of yoga was resulting in more injuries. For whatever reason or reasons, an American physician in the following year, 1973, made public a gruesome case study. The author was Willibald Nagler. He worked on Manhattan’s Upper East Side at the Weill Medical College of Cornell University. A world authority on spinal rehabilitation, he had counted President Kennedy among his patients.
In his report, Nagler described how a woman of twenty-eight, “a Yoga enthusiast” as he called her in the sketchy anonymity of clinical reports, had suffered a stroke while doing a position known in gymnastics as the Bridge and in yoga as the Wheel or Upward Bow (in Sanskrit Urdhva Dhanurasana). The posture begins with the practitioner lying on his or her back and then pushing up, balancing on the hands and feet and lifting the body into a semicircular arc. An intermediate stage can involve raising the trunk and resting the crown of the head on the floor.
Wheel or Upward Bow, Urdhva Dhanurasana
Nagler reported that the woman entered her crisis while balanced on her head, her neck bent far backward. While so extended, she “suddenly felt a severe throbbing headache,” he reported. She had difficulty getting up. After she was helped into a standing position, she was unable to walk without assistance.
The woman was rushed to the hospital and found to be experiencing a number of physical disorders. She could feel no sensations on the right side of her body. Her left arm and leg wavered. Her eyes kept glancing involuntarily to the left. And the left side of her face showed a contracted pupil, a drooping upper eyelid, and a rising lower lid—a cluster of symptoms known as Horner’s syndrome. Nagler reported that the woman also had a tendency to fall to the left.
Diagnostic inquiry showed that her left vertebral artery had narrowed considerably between cervical vertebrae C1 and C2, revealing the probable site of the blockage that resulted in the stroke. It also showed that the arteries feeding her cerebellum (the structure of the rear brain that coordinates the muscles and balance) had undergone severe displacement, hinting at trouble within. Given the day’s lack of advanced imaging technologies, an exploratory operation was deemed necessary to better evaluate the woman’s injuries and prospects for recovery.
The surgeons who opened her skull found that the left hemisphere of her cerebellum had suffered a major failure of blood supply that resulted in much dead tissue. They also found the site seeped in secondary hemorrhages, or bleeding. In response, the physicians put the woman on an extensive program of rehabilitation. Two years later, she was able to walk, Nagler reported, “with broad-based gait.” But her left arm continued to wander and her left eye continued to show Horner’s syndrome.
Na
gler concluded that such injuries appeared to be rare but served as a warning about the hazards of “forceful hyperextension of the neck.” He urged health professionals to show caution in recommending such difficult postures to individuals of middle age.
The next case came to light in 1977. The man of twenty-five had been in excellent health and doing yoga every morning for a year and a half. His routine included spinal twists in which he rotated his head far to the left and far to the right. Then, according to a team in Chicago at the Northwestern University Medical School, he would do a Shoulder Stand with his neck “maximally flexed against the bare floor,” echoing Iyengar’s call for perpendicularity in Light on Yoga. The team said the young man usually remained in the inversion for about five minutes.
One morning upon finishing this routine, he suddenly felt a sensation of pins and needles on the left side of his face. Fifteen minutes later, he felt dizzy and his vision blurred. Soon, he was unable to walk without assistance and had trouble controlling the left side of his body. The man also found it difficult to swallow. He was rushed to the hospital.
Steven H. Hanus was a medical student at Northwestern who became fascinated by the case. He took the lead and worked with the chairman of the department of neurology to elucidate the exact cause of the disabilities, publishing a study with two colleagues when he was a resident. The doctors saw many indications of stroke and, in their report, noted the similarity of the man’s symptoms to those of Nagler’s female patient. The man could feel little sensation on the right side of his body. His eyeballs twitched. His left arm and leg were weak, had poor coordination, and showed a prominent tremor when he tried to reach for something or move his hand or foot to a precise location.
During the physical examination, the doctors noticed on the man’s back a series of bruises. The bluish discolorations ran down his lower neck across the C5, C6, and C7 vertebrae. Apparently, the team wrote in the Archives of Neurology, “these resulted from repeated contact with the hard floor surface on which he did yoga exercises.” The bruises, the doctors added, were a sign of neck trauma.
Hanus focused on assessing the inner damage. Diagnostic tests revealed blockages of the left vertebral artery between the C2 and C3 vertebrae. The team found that the blood vessel there had suffered “total or nearly complete occlusion.”
During the man’s first week in the hospital, the left side of his face developed Horner’s syndrome—the constricted pupil and drooping eyelid. Slowly, he regained his ability to walk, though his gait remained clumsy. Two months after his attack, and after much physical therapy, the man was able to walk with a cane. But the team reported that he “continued to have pronounced difficulty in performing fine movements with his left hand.”
Hanus and his team concluded that the young man’s situation was no anomaly or medical oddity but instead a new kind of danger. Healthy individuals can seriously damage their vertebral arteries, they warned, “by neck movements that exceed physiological tolerance.” And yoga, they stressed, “should be considered as a possible precipitating event.” In its report, the Northwestern team cited not only Nagler’s account of his female patient but Russell’s early warning. The concern was beginning to ripple through the world of medicine.
The next case showed its global spread. In Hong Kong, a woman of thirty-four practiced yoga faithfully. One day, shortly after doing a Headstand for five minutes, she developed a sharp pain in her neck and numbness in her right hand. A surgeon made an incorrect diagnosis and prescribed neck traction and physical therapy. Her symptoms got worse. The attacks of nausea and dizziness grew in severity. Eventually her troubles came to the attention of a medical team at the University of Hong Kong and Queen Mary Hospital.
By this point—some two months after the neck pain—the doctors found that the woman showed signs of disorientation and paralysis on the left side of her body, as well as an inability to feel sensations of touch. Her eyes displayed the jerky movements typical of a rear-brain stroke, and the physicians made that the provisional diagnosis.
The doctors repeatedly scanned the woman’s brain with imaging devices over the next few days. But they found nothing, even as her consciousness began to ebb. Finally, the team located a region of tissue that appeared dead from lack of blood. It ranged over the pons, the thalamus, and the occipital lobe. The doctors sought to pinpoint the cause of the stroke by injecting dye into the woman’s neck arteries and taking X-rays. The diagnostic images showed no problems in the vertebral arteries but a severe blockage in the basilar artery.
The doctors had put the woman on blood thinners and clot-dissolving drugs after the provisional diagnosis. Eventually she underwent intensive physical therapy as well. After a year, she regained strength on the left side of her body. But she still exhibited clumsiness in her left hand.
Jason K. Y. Fong, a young neurologist, led the analysis. In 1993, he and his colleagues reported that the woman’s problems had probably begun when vertebral arteries in the C1–C2 region suffered a tear or a severe reduction in blood flow. That produced a clot, the doctors wrote in Clinical and Experimental Neurology, that eventually worked its way into the basilar artery and blocked the blood supply to her inner brain. They attributed the lack of visible damage in the vertebral artery to the likelihood that the exceptionally long period between the Headstand and the hospital admission “may have allowed sufficient time for spontaneous healing.”
The delay in uncovering the woman’s stroke and its likely cause bore lessons for the medical community, Fong and his colleagues argued. The main one was the importance of learning the inconspicuous details of case history, which if taken seriously could speed diagnosis and treatment. Their warning echoed Russell’s observation about overlooking the origin of brain damage.
The gravity of the Hong Kong case, the team concluded, showed that yoga could pose extraordinary risks to human health. The doctors cautioned that postures in which the neck came under great strain could be “potentially dangerous or even lethal.” The latter word is one that physicians, steeped in a culture of cautious optimism and dry understatement, tend to avoid if possible.
The spike in clinical reports made yoga strokes a common feature of medical concern. The danger was judged to be at least partly due to underlying weaknesses in the vertebral arteries of some individuals. But it was difficult if not impossible to know who was at risk. So the warnings spread. They appeared not only in medical journals but in textbooks as health specialists gained new appreciation of the threat.
Science of Flexibility, whose first edition appeared in 1996, featured a section called X-Rated Exercises. It linked strokes to poses that stretched the neck far backward, including the Wheel and the Cobra. In summarizing the medical findings, the book’s author called the value of the postures too small “to justify the potential, although rare, risk of vertebral artery occlusion.” He suggested avoidance.
Injuries due to yoga turned out to range far beyond nerve damage and strokes. Waves of practitioners were showing up in emergency rooms. The Consumer Product Safety Commission, in monitoring the hazards of modern life, runs a little-known detective service known as the National Electronic Injury Surveillance System. It samples hospital records in the United States and its territories. By 2002, its surveys showed that the number of admissions related to yoga, after years of slow increases, had begun to soar. The number of admissions went from thirteen in 2000 to twenty in 2001. Then, in 2002, they more than doubled to forty-six. By definition, all these episodes involved men and women (and in some cases children) who had hurt themselves badly enough to seek out emergency assistance.
The spike represented the tip of a very large iceberg, since the system of federal monitoring produced only a statistical sketch. Most emergency rooms lay beyond its reach. Moreover, only a fraction of the injured visited hospital emergency rooms in the first place. Many—perhaps most—went to family doctors, chiropractors, neighborhood clinics, drugstores, and various kinds of therapists. Some probably decid
ed to avoid treatment altogether and deal with the injury on their own. Thus, many hundreds or even thousands of yoga injuries in the United States went unreported.
The 2002 survey, like that of any year, gave a brief description of each person and each injury. An analysis of the information on the forty-six patients showed that they ranged in age from fifteen to seventy-five years, with the average age being thirty-six. The vast majority—83 percent—were women. The main type of injury centered on the complicated amalgams of bone, tendon, and cartilage known as joints, including the wrist (mentioned six times), the ankle and foot (five times), the knee (five times), the shoulder (four times), and the neck (four times). The injury write-ups contained an area for brief comments, which tended to describe everyday pains, strains, and sprains. But the comments also disclosed a number of serious traumas. Six of the injuries involved dislocations and fractures.
The survey listed no strokes—their diagnosis would typically require detailed examinations that went beyond the simple capabilities of most emergency rooms—but in several cases listed symptoms that might have coincided with the precipitating damage. “Acute neck pain,” read one write-up. “Collapsed to floor while performing yoga,” read another.
The brief comments tended toward the kind of pithy diagnoses and observations heard in emergency rooms: “dislocated right knee,” “hurt shoulder,” “low back pains.” The reports usually cited yoga in general as the cause of the accident but on occasion named specific poses. “Sharp pain in abdomen since doing Cobra,” read one report. Another said a male patient fainted while doing yoga in a warm room, falling and hitting his head hard enough to produce a bruise.
The wave—whatever its true dimensions—represented a clear rebuke to the “mother’s milk” argument. Facts can be stubborn things, and they now suggested that yoga had long involved not only celebrated benefits but a number of hidden dangers.
The Science of Yoga: The Risks and the Rewards Page 16
