The 4 Most Often Missed Diagnoses in the Spine
As a spine surgeon in an academic institution, I see a lot of the challenges that people face in trying to manage their back, neck, sciatica, pinch nerve, imbalance or other neurologic problems that may be referable to their spinal system. Frequently, I get patients to see me because nobody else has been able to identify what their condition is, and therefore what the appropriate treatment would be. I get referrals from all over: chiropractors, physical therapists, internists, word of mouth, friends, family; you name it, if somebody has a problem that can’t be solved, they eventually find me.
Common things happen commonly, but when the problem does not seem to be getting better with standard conservative treatments, we sometimes have to open up our minds and consider some of the less common diagnoses; and even more important is to be aware that there are several diagnoses that are often overlooked and especially in this patient population, of the patient with a problem that is not responding to standard treatments, it’s time to consider that there may be something else going on.
Going from the top of the neurologic system down, four diagnoses that I find are often overlooked, even by trained spine surgeons, are as follows: Chiari malformation, congenital cervical or lumbar stenosis, lumbar far-lateral disk herniation, and Bertolotti’s Syndrome. That is not to say that these four diagnoses are the only things that can cause a neurologic problem that might not be obvious to the average practitioner of the art of spinal management; thoracic disk herniations, various cysts extruded from one joint to another in the spine, infections, trauma, fractures, tumors and the like are also clearly things that we keep in our differential diagnosis. But these four, I find, are the most frequently overlooked by other surgeons, and require a very suspicious or cautious eye when evaluating the imaging of a patient whose diagnosis is yet to be completely determined.
1. CHIARI MALFORMATION
A Chiari malformation is a congenital anomaly that results in the patient’s cerebellar tonsil (the vestigial or minimally useful portion of the brain) that then projects down through the bottom of the skull into the top of the spinal canal where it causes compression on the upper cervical spine and in some cases is associated with downwards projection of even a part of the brain stem; see diagram, where the blue arrow points to the tonsil herniating below the level of the foramen magnum (bottom of the skull, yellow line).
A Chiari (Type I typically) malformation can be associated with many different neurologic syndromes, but two associations require special attention.
The first scenario is that a patient might have a relatively mild Chiari malformation, but if they suffer trauma that involves a whiplash type injury to the head and neck, this can induce neurologic dysfunction, disproportionate to the severity of the injury. The sensitivity to injury, causing spinal derived neurologic symptoms, is not well understood and many practitioners have either not noticed the Chiari malformation (precisely because it is on the milder edge of the spectrum), or they have felt that one would not normally expect this degree of injury and do not realize that the Chiari sensitizes you to further spinal dysfunction.
The second association is with concussions and post-concussive syndrome (PCS); having a Chiari malformation makes you far more likely to suffer from and have prolonged effects of a concussion, presumably due to the dampening of the spinal fluid waves when the head is struck. This is seen in all forms of athletes as well as minor injuries with people playing sports at all levels or other fall-type injuries. The underlying anatomy of the Chiari potentiates neurologic deficits. The key is to recognizing and then potentially treating the Chiari malformation to minimize long term consequences, or realizing that the Chiari will predispose to more injuries and concussions, and considering sports or a lifestyle with less contact that could lead to concussions.
2. CONGENITAL CERVICAL AND/OR LUMBAR STENOSIS
About 10% of the population has a smaller (10-12 mm or so) than average spinal canal (normal diameter 15-18 mm at widest point, see image below) that can potentially lead to further consequences or neurologic dysfunction. First let me say that not every patient with congenital stenosis will develop symptoms; they may never require treatment of any kind. But if there is neurologic dysfunction in the setting of an already small spinal canal, that small spinal canal is likely contributing to the degree of severity and lack of response of the patient’s neurologic issue. In addition to the impact a tight canal has on the spinal cord, having a tight spinal canal means that any arthritic degeneration in the disks and other joints of the spine will be magnified in clinical relevance and severity because there is less room for the spinal cord or nerve roots to move back away from these degenerations or disk herniations.
To look at it differently, if you live in a small Manhattan studio apartment, you really do not have room for grand piano; where as if you live in a large country home, a grand piano can be accommodated easily without making the house feel small. Similarly, disk herniations, bulges and bone spurs that might normally cause no symptoms can become symptomatic very easily when there is little room for the spinal cord to accommodate (or worse, to swell in the setting of minor or major injury). The treatment plan needs to take into account the presence of the congenital stenosis as well as the presence of whatever focal issues may be present. I do not know how many times I have seen a patient come in who has had a anterior cervical diskectomy at one or two levels when the primary problem was the congenital stenosis.
3. FAR LATERAL LUMBAR DISK
Many patients present to me with sciatica; and some patients come to me specifically because they know about my expertise in minimally invasive surgical procedures as well as my attention to detail*see below*. But sometimes, patients come to me with sciatica, leg weakness or some other neurologic problem and it has been either after they failed to improve from one procedure that was geared towards treating a standard location herniated disk, or for a second opinion and they hear something completely different; see figure 3A. The symptomatic disk herniation is located in a slightly different area (that is often overlooked even in radiology reports, see below for an example where the left image looks relatively normal, but at the level of the blue line on the left, the image on the right shows a black shadow outside the canal that is pinching a nerve at the larger blue arrow, as opposed to the normal side, with the small arrow. The curved line shows the normal bone anatomy, with the dark shadow all being disk herniation where it doesn’t belong).
Far lateral disks can compress the nerve root as it is exiting the spine and because it does not displace spinal fluid, maybe missed by the practitioner who is only looking for the common and not the unusual or the infrequent. But when you treat thousands patients a year even uncommon things become common and need to be considered on every case. These patients respond very well, if the appropriate level is identified and the treatment (therapy, injections, surgery etc) are geared towards that particular location. After all, if somebody thinks that a small bulge at L4/5 is causing the patient’s symptoms, but it is really the far lateral disk at L5/S1, what chance do you think the patient has to get better from a surgery at the L4/5 level?).
We know that about 40% of patients walking around (with no symptoms at all) can have abnormalities on their MRI; this tells me that not all radiographic findings need to be treated. It points out the fact that people could have one radiographic finding that is not related to their problem and a second one that is and one needs to drill down carefully with testing, examination, questioning and other aspects of the diagnostic workup to accurately identify the primary pain generator before attempting any invasive treatments.
4. BERTOLOTTI’S SYNDROME
Bertolotti’s Syndrome is a long diagnosed, but poorly recognized and understood entity that results from a combination of factors: A congenital anomaly also known as a lumbosacral transitional vertebra (LSTV, see figure 4A) as well as degeneration in the disks or a scoliosis that results in a worsening in the biomechanics of the spine at the level of the congenital anomaly. This often results in pain that can mimic a herniated disk, result in back pain or even hip or sacroiliac region pain. Because the presentation is very broad, it is important to consider this in the diagnosis of various items, various maladies that affect this area, but also to have a careful eye to making the diagnosis; not every patient with a congenital anomaly of an LSTV has the clinical syndrome of Bertolotti syndrome. In the image below, the red arrow points to a proximity or type I interface, and the blue arrow points to an articulation type, or type II interface, according to the old Castelvi classification.
Therefore to determine if the Bertolotti is indeed their pain generator, one should attempt to perform diagnostic injections directly at the transverse ala junction. If their typical pain is transiently (1 hour to 1-2 weeks) alleviated by these injections, then the diagnosis of Bertolotti is relatively secure (about 95% in our experience). Having said that, it is not uncommon for patients to have arthritic degeneration in disks, facet joints, scoliosis, and other conditions that may be the primary pain generator and the LSTV is not, which is why performing the diagnostic injections is so important.
Making the CORRECT diagnosis is central to developing an effective treatment strategy. Not every patient with a diagnostic dilemma has one of these four diagnoses; however, I would have to say more often than not when a patient comes in and says, “…nobody could figure out what is going on with me”, it is one of these four items.
Therefore, bear with me when you come in to have me evaluate your condition, as we may have some additional diagnostic and/or therapeutic tests to go through before we come to a definitive diagnosis, and then a settle on a comprehensive and stratified treatment plan that starts with the least invasive and works our way to a (hopefully) definitive solution.
The good news: there are very few patients that I cannot come up with a treatment plan for, although there are certainly many conditions for which surgery is not going to make the patient any better. But for those for whom we know surgery is a reasonable option (when less invasive measures have failed to result in permanent improvement), we are able to do the surgical procedures with low risks to the patient and high therapeutic yield.
I always strive to do the most for my patients and the least to them, by keep my complication rates exquisitely low, and only doing those procedures which are likely to benefit you as the patient: my mission as a physician and surgeon.