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Frequently Asked Questions
Questions Posed by Medical Professionals

#1- Question: When the MRI shows a bulging or herniated disc, what percent of the time is this false positive result?

Answer: In an article by Jensen (Jensen MC, Brant-Zawadzki MN, Obuchowski N, Modic MT, Malkasian D, Ross JS, Magnetic resonance imaging of the lumbar spine in people without back pain., N Engl J Med. Jul 14;331(2):69-73..1994) his group reported that in a sample of 91 patients, WITHOUT any back pain, 27 of these patients have a bulging or herniated disc on MRI images. Therefore, 30% of the time (27/91) the MRI shows a disc abnormality, but the patient does not have any symptoms. Therefore, for discs in the lower back, the MRI has a false positive rate of 30%.

#2- Question: Can EMG/nerve conduction studies tell if a patient has pain.

Answer: Not very well. Electromyographic studies and nerve conduction studies primarily measure motor fiber conduction speed and the integrity of the muscle fibers. Peripheral nerves are really a collection of both sensory and motor nerves. Various nerve roots coming off the spinal cord mix in the plexus (brachial or lumbar plexus) and go to the arms and legs as mixed motor-sensory nerve. Therefore, the ulnar nerve, which arises after the brachial plexus (a mixed peripheral nerve) is a collection of inputs from the C4, C5, C6 and C7 and sometimes, T1 nerve roots, which contribute input before the brachial plexus. Sensory nerve messages are carried by the C fibers, A beta fibers and A delta fibers, which as small diameter, sparsely myelinated fibers, while the motor fibers are large diameter, heavily myelinated fibers. If you cut a nerve in half, and look at the various types of nerve fibers within a nerve bundle, over 90% of the nerve fibers are motor fibers, and less than 10% are sensory nerve fibers. Therefore, you can have extensive damage to the sensory nerves, but have very little effect on the conduction speed and amount of recorded electrical activity in a "nerve."

# 3- Question: When the MRI doesn't show a bulging or herniated disc, what percent of the time is this a false negative result?

Answer: Sandu at Cornell reported that in 53 patients with severe back pain had normal MRIs of their back, but when they received a test which stimulated the pain fibers in the disc level that corresponded with the level where they experienced pain, (a provocative discogram), this test found that 41 of the 53 (78%) reported this test duplicated their pain (Sandhu HS, Sanchez-Caso LP, Parvataneni HK, Cammisa FP Jr, Girardi FP, Ghelman B., Association between findings of provocative discography and vertebral endplate signal changes as seen on MRI., J Spinal Disord., Oct;13(5):438-43, 2000). Therefore, the MRI has a false negative rate of 78%. Brathwaite found comparable results (Braithwaite I, White J, Saifuddin A, Renton P, Taylor BA. Vertebral end-plate (Modic) changes on lumbar spine MRI: correlation with pain reproduction at lumbar discography, Eur Spine J., 7(5):363-8, 1998).

#4- Question: Is there any difference between a CT and a 3D-CT?

Answer: Yes. The CT is a widely used test for determining bony lesions, and solid lesions in the lung, liver, brain, kidney and other parts of the body. However, in research from Johns Hopkins University School of Medicine, Zinreich, the acting head of neuroradiology, Long the former chairman of neurosurgery and Davis, their orthopedic colleague, evaluated 100 patients with severe back pain, who had a normal CTs of the back, and no history of prior surgery. When a 3D-CT reformatting was done, bony lesions were discovered in 56% of the patients. In 100 patients who had prior surgery on their back, and who still had symptoms of pain, but had a normal CT, the 3D-CT found bony lesions, missed by the regular CT, 76% of the time. (Zinreich, J., Long, D., Davis, R., et al, Three dimensional CT imaging on post-surgical "Failed Back" Syndrome, J. Comput Assist. Tomograph, 14:574-580, 1990).

#5- Question: What percent of the time are chronic pain patients misdiagnosed?

Answer: There is a 40%-67% chance that a chronic pain patient is misdiagnosed or undiagnosed i.e. has an overlooked diagnosis. (Overlooked Physical Diagnoses in Chronic Pain Patients Involved in Litigation, Psychosomatics, Vol. 34, #6, pp. 494-501, Nov.-Dec. 1993, N, Bergson, C, and Morrison, C, Overlooked Physical Diagnoses in Chronic Pain Patients Involved in Litigation, Part 2, Psychosomatics, Vol. 37, #6, pp. 509-517, November-December. 1996). In the case of RSD (CRPS) this misdiagnosis rate may reach 71%, Differential Diagnosis of Complex Regional Pain Syndrome, Pan-Arab Journal of Neurosurgery, pp 1-9, October, 2002.) and if there is an electrical shock or lightning strike involved in the cause of the injury, the misdiagnosis rate may reach over 90% Overlooked Diagnosis in Electric Shock and Lightning Strike Survivors, Journal of Occupational and Environmental Medicine, Vol. 47, No. 8, pp. 796-805, Aug. 2005).

#6- Question: Is there a test to measure sensory nerve damage?

Answer: Yes. There is a sensory test that measures just the three types of sensory nerve fibers which are the A beta, A delta and C fibers, which have relative sizes of a fire hose, a garden hose, and a soda straw. This is called a current perception threshold test (CPT) and this demonstrates damage to the sensory nerves, by measuring the ability to detect electric shock, which is a sensory phenomenon, using the specific frequencies detected by each of the three sensory nerves. The machine that makes these measurements is a Neurometer, and is made in Baltimore, Maryland. (Katims, JJ, Electrodiagnostic functional sensory evaluation of the patient with pain: A review of the neuroselective current perception threshold (CPT) and pain tolerance threshold (PTT), Pain Digest, 8:219-230, 1998).

#6- Question: Are X-rays of any use in detecting pathology in chronic pain patients?

Answer: No. In many studies of the value of X-rays, an anatomical test that detects bony pathology, the correlation between the subjective symptoms, and the findings on X-ray fairly well indicate that X-rays are of little use in accessing objective pathology in the neck and lower back, because there are too many other structures, other that bony lesions, that can cause pain, which just do not show up on X-ray. (Peterson, et. al., Spine # 28 (2) pp 129-33, '03).

#7- Question: Can a disc that is not herniated cause pain?

Answer: Yes. A disc is like a jelly doughnut, with the annulus being analogous to a doughnut, and the nucleus pulposa being analogous to the jelly inside a doughnut. Most physicians do not know that there are pain fibers in the rear one third of the annulus, or the doughnut portion, that, when anatomically compressed, mechanically disrupted, or chemically irritated, will produce pain that feels exactly like a herniated disc pushing on a nerve root. However, this "internal disc disruption," i.e. the herniation of the nucleus pulposa into the posterior portion of the annulus, does not show up on the anatomical tests such as MRI, CT or myelogram, because there is no anatomical distortion the annulus, and no protrusion of the nucleus pulposa (jelly) beyond the annulus (doughnut). (Bogduk and McGuirk, Pain Research and Clinical Management, Vol. 13, p.119-122, Elsevier, 2002).

#8- Question: Is there a test to tell if a patient has a valid complaint of pain?

Answer: Yes. The Pain Validity Test shows if your patient's complaint of pain is valid. This test is available on-line at www.MensanaDiagnostics.com. It is 32 questions long, and takes about 10 minutes to complete. Results are available in 5 minutes. If a patient scores as an objective pain patient, then there is a 94% chance that they will have a moderate or severe abnormality on objective medical testing, proving organic pathology, if proper testing is used. (Cashen, A, S, Bringham, C, Osborne, P, LeRoy, P, Graybill, T., Catlett, L, and Gronblad, M, A Multi-Center Study for Validating the Complaint of Chronic Back, Neck and Limb Pain Using the Mensana Clinic Pain Validity Test, The Forensic Examiner, Vol. 14, No. 2, pp. 41-49, Summer 2005, Hendler, N, and Baker, A., Abstract 1022, A Computer Administered and Scored Test to Validate the Complaint of Chronic Pain, American Psychosomatic Society, 64th Annual Meeting, Denver, CO., March 2, 2006, Baker, A., An Internet Questionnaire to Predict the Presence or Absence of Organic Pathology in Chronic Back, Neck, and Limb Pain Patients, Pan-Arab Journal of Neurosurgery, April 2008).

#9- Question: Is it normal to get depressed because of pain?

Answer: Yes. Psychiatric problems arise as the result of chronic pain. (Hendler, N, Depression Caused by Chronic Pain, J. of Clinical Psychiatry, Vol. 45, pp. 30-36, 1984, Chapter 1, The Four Stages of Pain, in Diagnosis and Treatment of Chronic Pain, Edited by D. Long, and T. Wise, John Wright/PSG, Littleton, Mass, pp. 1-8, 1982). 77% of patients seen had coexisting depression and chronic pain, but when questioned about pre-existing depression, 89% of the patients had never had significant depression before the onset of their pain (Validating and Treating the complaint of Chronic Pain: The Clinic Approach, in Clinical Neurosurgery, Edited by P Black, Williams and Wilkens, Baltimore, Vol. 35, Chapter 20, pp. 385-397, 1989)

#10- Question What is the difference between anatomical and physiological testing?

Answer: Very often, physicians fail to recognize the distinction between anatomical tests, and physiological tests, which is a critical issue, since each category of testing provides a different answer to the same question, and the degree of correlation is very poor. An anatomical test merely takes a picture of a structure, while a physiological test records a person's response to an event. As an example, X-rays, CT, and MRI are merely anatomical tests, because all they do is take a picture. However, a bone scan, or Indium 111 scan, or PET scan or Gallium scan takes a picture of the physiological uptake of various chemicals, and nerve conduction velocity studies measure the speed of response to a nerve when you put an electrical current into it. The same rationale applies to the use of other physiological tests, used to make diagnoses in chronic pain patients, such as root blocks, nerve blocks, facet blocks, neurometer studies, somatosensory evoked potentials, and flexion-extension X-rays with obliques.

#11- Question: What is meant by the medical term "convergence," and why is this important?

Answer: Convergence means that multiple events produce the same results. As an example, pain in the little and ring finger can be caused by ulnar nerve entrapment or nerve root compression at C6-7 or even thoracic outlet syndrome. Clearly, this has clinical significance, because understanding the concept of convergence helps with clinical diagnoses.

#12- Question: What is meant by the medical term "divergence," and why is this important?

Answer: Divergence means that multiple, and different events are produced by the same etiological cause. As an example, damage to the vagus nerve can produce esophageal spasm, hyper-acidity in the stomach, or rapid heart rate. Clearly, this has clinical significance, because understanding the concept of divergence helps with clinical diagnoses.

#13- Question: What is a provocative discogram?

Answer: Central to understanding the value of the provocative discogram the concept that pain is a physiological condition, not an anatomical event. While the use of an MRI can detect only anatomical distortions, the use of the provocative discogram, which is a physiological test, is more reliable for diagnosing chronic pain. A disc is like a jelly doughnut, with the annulus being analogous to a doughnut, and the nucleus pulposa being analogous to the jelly inside a doughnut. Most physicians do not know that there are pain fibers in the rear one third of the annulus, or the doughnut portion, that, when anatomically compressed, mechanically disrupted, or chemically irritated, will produce pain that feels exactly like a herniated disc pushing on a nerve root. However, this "internal disc disruption," i.e. the herniation of the nucleus pulposa into the posterior portion of the annulus, does not show up on the anatomical tests such as MRI, CT or myelogram, because there is no anatomical distortion the annulus, and no protrusion of the nucleus pulposa (jelly) beyond the annulus (doughnut). (Bogduk and McGuirk, Pain Research and Clinical Management, Vol. 13, p.119-122, Elsevier, 2002). To perform a provocative discogram, a needle is inserted into the posterior portion of the disc, and saline is injected. If the saline injection reproduces the pain the patient normally feels, then the disc is the one causing the pain, regardless of the anatomical picture of the disc.

#14 Question: What is "Internal Disc Disruption?"

Answer: A disc is like a jelly doughnut, with the annulus being analogous to a doughnut, and the nucleus pulposa being analogous to the jelly inside a doughnut. Most physicians do not know that there are pain fibers in the rear one third of the annulus, or the doughnut portion, that, when anatomically compressed, mechanically disrupted, or chemically irritated, will produce pain that feels exactly like a herniated disc pushing on a nerve root. However, this "internal disc disruption," i.e. the herniation of the nucleus pulposa into the posterior portion of the annulus, where the pain fibers are, does not show up on the anatomical tests such as MRI, CT or myelogram, because there is no anatomical distortion the annulus, and no protrusion of the nucleus pulposa (jelly) beyond the annulus (doughnut). (Bogduk and McGuirk, Pain Research and Clinical Management, Vol. 13, p.119-122, Elsevier, 2002).

#15 Question: Can Waddell signs predict secondary gain or malingering in a patient?

Answer: No. Waddell signs are a group of 8 physical findings divided into 5 categories, the presence of which has been alleged at times to indicate the presence of secondary gain and malingering. These consist of hitting a person on the top of the head, and having the patient experience back pain, etc.(Waddell, G., McCullock, J.S., Kummel, E., Venner, R.M. "Nonorganic Physical Signs in Low Back Pain," SPINE, Vol. 5, pp. 117-125, 1980). However, in a meta-analysis of 16 studies, Fishbain could not find any predictive value nor correlation with other studies to detect malingering. (Fishbain DA, Cutler RB, Rosomoff HL, Rosomoff RS., Is there a relationship between nonorganic physical findings (Waddell signs) and secondary gain/malingering? Clin J Pain. 2004 Nov-Dec;20(6):399-408)

#16-Question: Are epidurals effective for reducing neck and back pain?

Answer: Not really. In a study of 300 patients, after 2 to 6 weeks, most epidural blocks loose their effectiveness. There was no efficacy at 3 months, 6 months or 1 year after injection. The epidurals had no impact on day to day functioning, the need for surgery or long term pain control. (Hampton, Tracy, Epidurals' benefit for back pain questioned, JAMA, Vol. 297 # 16, pp: 1757-1758, April 25, 2007), (Landau WM, Nelson DA, Armon C, Argoff CE, Samuels J, Backonja MM., Assessment: use of epidural steroid injections to treat radicular lumbosacral pain: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology, Neurology. 2007 Aug 7;69(6):614)

#17-Question: What are facet blocks?

Answer: Facet blocks mean injecting a local anesthetic agent, such as bupivocaine, next to the part of the vertebral body called the facet. The facet is a bony joint that keeps the vertebral body from moving too far side to side in the lumbar region, and too far up and down in the cervical region. The block typically lasts only one hour, and tells the doctor if the facet joint or excessive movement around the joint, is the source of the pain.

#18 – Question: Why do you do a facet block?

Answer: Since the facet is a bony joint that keeps the vertebral body from moving too far side to side in the lumbar region, and too far up and down in the cervical region, any excessive motion around this joint will produce pain that is localized to the joint area. A facet block typically lasts only one hour, and tells the doctor if the facet joint or excessive movement around the joint, is the source of the pain. Typical radiological findings suggesting the need for a facet block are facet hypertrophy, or anteriolythesis, or retrolysthesis on flexion-extension X-rays.

#19-Question: What are root blocks?

Answer: Root blocks mean injecting a local anesthetic agent, such as bupivocaine, next to the part of the vertebral body called the foramen, which is formed by an upper and lower facet. The foramen is where the nerve root exits from the spinal canal, and then goes to either the lumbar or cervical plexus. The block typically lasts only one hour, and tells the doctor if the neural foraminal stenosis or excessive movement around the joint, is the source of the pain.

#20– Question: Why do you do a facet block? 

Answer: Since the neural foramen is an opening between two vertebral bodies, if the opening is too small, or if the vertebral body move too far side to side in the lumbar region, and too far up and down in the cervical region, any excessive motion around this joint will produce pain in the distribution of the nerve root. A facet block typically lasts only one hour, and tells the doctor if the neural foraminal stenosis is clinically significant, or excessive movement around the joint, is the source of the pain. Typical radiological findings suggesting the need for a root block are facet hypertrophy, or anteriolythesis, or retrolysthesis on flexion-extension X-rays, neural foraminal stenosis on MRI or CT, or disc herniation compressing the nerve root.

#21-Question: What is a peripheral nerve block?

Answer: A peripheral nerve block mean injecting a local anesthetic agent, such as bupivocaine, next to a mixed peripheral nerve. A mixed peripheral nerve is one that emerges after the lumbar or cervical plexus, and this nerve typically carries mostly motor fibers, and some sensory fibers. The peripheral nerve block typically lasts only one hour, and tells the doctor if the source of the leg or arm pain is occurring after the lumbar or brachial plexus.

#22– Question: Why do you do a peripheral nerve block? 

Answer: Nerve roots leave the spinal cord, and mix in either the lumbar or brachial plexus, emerging as mixed peripheral nerves, having both motor and sensory contributions from various nerve roots. A mixed peripheral nerve block typically lasts only one hour, and tells the doctor if damage to the nerve after emerging from the plexus is clinically significant, and the source of the pain. There are no typical radiological findings suggesting the need for a mixed peripheral nerve block. There best way to detect peripheral nerve damage to the motor component is EMG, nerve conduction velocity studies. To tell if the is damage to the sensory component, use the current perception threshold test with a Neurometer machine. Even if both of these tests are normal, it is still worth while to do a peripheral nerve block.

#23 –Question: What is a two poster brace?

Answer: A two poster brace is a brace that supports the neck both front and back. This is the most rigid and reliable of the bracing devices for the neck. The brace has metal supports, and straps that adjust across the shoulders. The brace should be adjusted so that there is slight pressure at the back of the head but little pressure on the chin, and no movement of the head should be detected when the brace is on.

#24 –Question: Why use a two poster brace?

Answer: A two poster brace is a brace that supports the neck both front and back. This is the most rigid and reliable of the bracing devices for the neck. By holding the neck rigidly, and preventing movement, a doctor can tell if preventing motion will reduce the pain in the neck and or in the neck and arms. If the brace helps, then the doctor knows that the source of the pain is excessive motion around the joints, or vertebral bodies of the neck, and the patient would benefit from trials with facet blocks, and if these don't last, then a fusion (Long, D, Davis, R, Speed, W, and Hendler, N, Fusion for Occult Post-traumatic Cervical Facet Injury, Neurosurgery Quarterly, Vol. 16, No 3, pp 129-134, Sept. 2006)

#25 Question– What is a body jacket with a thigh spika?

Answer: A body jacket with a thigh spika is a full body cast, for the lower back, with an extension that goes down the leg that does not have pain. If a patient has pain in both legs, then the spika should be placed on the leg with less pain. The thigh spika body jacket is the only low back brace that stabilizes L5-S1 lumbar segment, which is where 87% of all low back and leg pain occurs.

#26 – Question: Why use a body jacket with thigh spika?

Answer: The thigh spika body jacket is the only low back brace that stabilizes L5-S1 lumbar segment, which is where 87% of all low back and leg pain occurs. If the patient improves after a 3 day trial in the brace, then the doctor knows that there is excessive mobility in the lumbar spine, and the patient would probably benefit from facet blocks, and if these don't last, then a fusion.

#27 Question: What\ is the most common pathology of "whiplash" injury, after an automobile accident?

Answer: Most often, damage to the facet joints of the upper neck produce long lasting and headaches, unresponsive to medical treatment, that may persist for 6 months or longer after the accident. (Long, D, Davis, R, Speed, W, Fusion for Occult Post-traumatic Cervical Facet Injury, Neurosurgery Quarterly, Vol. 16, No 3, pp 129-134, Sept. 2006)