Bertolotti’s syndrome, first described by Mario Bertolotti in 1917, is a clinical syndrome of pain, caused by lumbosacral transitional vertebra. Lumbosacral transitional vertebrae are essentially a hybrid form of the junction of the lumbar spine (lower back) and the sacrum, also known as the corner stone of the pelvis. The entire spine sits on the pelvis and is connected to our legs through this triangular shaped bone that developed out of the exact same tissue in utero before birth as the rest of all the spinal bones. However, different chemical and hormonal gradients (i.e. more of one, less of another) in the area caused in most people five lumbar mobile vertebrae to form and in most people five lumbar segments to fuse into one large block of bone that the rest of the spine sits on. The anatomy is intended to be very distinct between the two lumbar vertebrae have handlebar-like arms coming off the side and the back that act as levers for muscles that supports the spine to attach to steer the mobile spine in different directions of down, left, light, pitch, yaw and roll. The sacrum is intended to be foundation that these mobile segments attached to. It is intended to be as distinct sacrosanct as the separation of church in state in the American government. However, just as elsewhere in life, boundaries and definitions are sometimes blurred and hybrid vertebrae can develop if the chemical signals at the time of development are not as distinct. This happens so frequently that depending on their definition, disc hybridization or transitional vertebrae development can happen in between one fifth and even one third of all people alive today. If this is such a common development, how would evolution have allowed this to be propagated? The answer is twofold. One is that they do not always cause pain. Therefore, when it is not painful, it is not an evolutionary disadvantage. Second is that human reproduction usually takes place at an age younger than many patients with this finding would be developing these symptoms. Third, we are living long enough now that our life span exceeds our reproductive span and things that happen to us late in life that might be suboptimal still will not preclude us for reproducing successfully.

How does transitional anatomy cause pain? That depends on what type of transitional anatomy we have.

Type 1 anatomy is where the transverse processes are closer to the handlebar equivalent on the sacrum, known as the ala, and can present a contact point between two bones. This close contact point between the bones was not originally intended and does not have therefore, a protective measure, like a bursa (fluid-filled cushion that can normally protect the bone from pressure or contact) or special ligaments or muscles to stabilize further. This proximity can then lead to bone-on-bone contact causing pain in the area for mechanical or chemical (from inflammation that develops from inappropriate bone on bone rubbing) on the exiting L5 nerve that runs past this area. When the transverse process is long enough, it can make inappropriate contact with the iliac bone, which is adjacent to the sacrum, normally it only has contact with the sacrum. This can sometimes also cause pain radiating to the hip region, often confusing clinicians unfamiliar with Bertolotti’s syndrome into thinking there is primary hip joint pathology. I have seen several patients who have had hip replacements whose hip pain did not get better until we treated their Bertolotti’s syndrome.

With patients who have type 2 anatomy, there is existing bone-on-bone contact, known as a pseudoarticulation, and pseudoarticulation is presumed to result in direct contact of sacrum and more frequently the ileum and it is the direct mechanical contact that is most often the direct pain generator either in the local region where the anomaly exists (also known as the sacroiliac region), but also into the hip region as well. Interestingly, type 2 anatomy is less likely to cause pain to go down the L5 distribution in a sciatica-like pattern than type 1’s are.  Groin pain, also part of the L5 contribution to the genitofemoral nerve, seems also be present in both type 1 and type 2 anatomy. There are three subtypes of type 2 anatomy depending upon the degree of transverse process hybridization on the less severe side arranging from normal anatomy (about a 2 cm gap between the two processes), type 1 anatomy where there is a gap, but it is less than 1 cm, or another pseudoarticulation. Interestingly, the type 2C (one type 1 and one type 2) are the most common form seen that have presented to my clinic in the hundreds of patients that I have seen.

Type 3 anatomy, where both sides appear to be solidly fused and non-pseudoarticulations, rarely does seem to cause pain. This is confirmed with injections into the region where the pseudoarticulation has presumably taken place as a solid fusion by injecting this area with local anesthetic does seem to take away their pain for a limited period of time. For that reason, we hypothesize that there is something in that area, some tangle of scar and inflammation, that result in this pain possibly due to the fusion occurring after development began and nerves being trapped in the fusion mass. Because of the limited number of patients presenting for treatment with this condition, we do not have as clear of treatment guidelines for these patients, but we will continue and as time progresses, we anticipate having a better understanding of both diagnosis and treatment.

Type 4 anatomy, where it appears to be solidly fused on one side and incompletely or not abnormal anatomy on the other side also can cause pain. The interesting part of this presentation is that for many patients the pain is on the side that appears to be fused.  Frequently, but not always, fusing the unfused side makes both sides feel better. One of the challenging parts of the diagnosis and treatment of these anomalies is that sometimes we can be fooled by even the best CT and MRI and x-ray imaging as to whether a side is fused or merely looks fused, and in other cases what appears to be a fusion may be an evolving stress fracture on the verge of developing into a full-blown fracture. It is important to truly understand these processes, to look at imaging and to understand the evolution, not just in the three dimensions we can see in radiologic imaging, but over time as well to understand which ways certain processes are progressing such as either a healing fusion or an evolving stress fracture.

Complexity breeds uncertainty. Making the diagnosis is hard enough, convincing skeptics who do not believe in Bertolotti’s syndrome, or that transitional anatomy can even cause pain or be relevant to the patient’s clinical presentation, is an equally large challenge. Sadly, this is an example of “Wrogma”, when somebody is repeating wrong dogma that they heard from somebody whom they respected enough to accept this statement of insight that was actually outside the realm of evidence-based medication. Most Bertolotti’s deniers base their argument upon the Castellvi classification and description article of lumbosacral transitional vertebrae from 1984. However, this misunderstanding of the biomechanics and pain generation from lumbosacral transitional vertebrae has its routes even further back to the 1950’s. The problems stem from the fact that Castellvi classification system was not geared towards identifying patients who have pain, it was designed specially to identify only those patients who have a herniated disc at the lumbosacral transitional level. What we cannot ask the venerable, but in this case, misaligned Dr. Castellvi what he intended his classification to be used for, but we note that it is almost universally used as justification for not treating with patients with transitional anatomy at the transitional points. I do agree that patients, as Dr. Castellvi pointed out in his article, with type 1 anatomy are more likely to have disc herniations at the transitional levels, those clearly do not have Bertolotti’s syndrome if the disc herniation is what is causing a pain. However, Dr. Castellvi’s classification system was based upon only one-dimensional analysis, the linear coronal plane length of the transverse process at its widest. This is only a small aspect of the radiologic finding in lumbosacral transitional vertebra, including underdevelopment of hypoplastic discs, of sweeping sacral ala, underdeveloped facet joints, underdeveloped paraspinal muscles, smaller than average vertebral body, among others. This seems odd that the linear length of the transverse process would be related to any pain generation, especially taken in the absence of any other radiologic findings. In fact, it is so dramatic that we published a case report of a patient who failed Castellvi classification but was verified with diagnostic injections and then improved with Bertolotti’s targeted surgery to prove the need to re-evaluate the classification system to include patients such as this and then our subsequent series on diagnosis and treatment we show that 75% of the patients with type 1 anatomy who are confirmed to have Bertolotti’s would be misdiagnosed as having normal anatomy using the Castellvi classification system.  In addition, the Castellvi classification system misses two specific anatomic variants that are frequently identified. Therefore, we redefined the anatomy of the transitional vertebrae based more on the proximity of the transverse-ala region rather than a linear measurement of one component alone. This made sense after seeing the dozens of patients whose Castellvi classification did not fit their pain, which also makes sense, since if they do not have disc herniation, the Castellvi classification is pointless. It is not a transitional vertebra identification system or a Bertolotti’s identification system, it is a disc herniation identification system and disc herniations are actually rarely the cause of pain in patients with transitional anatomy and when they are, one simply treats the disc herniation and not the transitional anatomy, or in some cases, both are equal parts of the pain generation and then we treat both.

General medical recognition of Bertolotti’s syndrome is endemic. I did not hear about it until I was in practice for 10 years, when a patient first presented to me with it. It was not a subject to be studied in my neurosurgical board. It was not something my mentors even mentioned to me. Ironically, this patient who thought he had Bertolotti’s syndrome did not, but he did have the anatomy. We did do diagnostic testing at the site of the transitional anatomy, and he got no relief. He did get relief from an injection at the level above (a frequent secondary findings in patients with transitional anatomy) and he responded to treatment at that level instead of at his transitional level. However, it got me thinking. It sparked my reading on the subject, and it made me wonder what had I been missing by not knowing about this possible pain generator for the last 10 years and in fact for the entire length of my medical school and residency training? And if I do not know about it, how would anybody else? That sparked a 12-year research project that continues to date looking into understanding biomechanics, the genetics, psychology and the treatment of patients who suffer from Bertolotti’s syndrome. It has also enhanced my understanding of spinal developmental variations and biomechanics so that I understand that transitional anatomy can occur at any junction between different spinal regions. Thoracolumbar transitional anatomy manifests itself as variation in ribs length, orientation and relative stability. Cervicothoracic transitional anatomy manifests itself as cervical ribs and various (sometimes bizarre) anatomic variants that can cause pain locally and down the arm and into the chest and neck. Craniocervical transitional anatomy includes variations on stimulation of C1 into the skull base and forms of craniocervical instability. If the spine can differentiate between regions, there can be a spectrum of how adherent a patient’s development is to the original architectural plans. Interestingly enough, patients with lumbosacral transitional vertebrae are also more prone to other regional transitional vertebrae development and should be screened for symptoms hinting at these findings being pain generators that they have not discussed with me and may even have motr genetic under findings to learn.

Every question I get answered seems to generate two new questions that need to be answered to understand the subject better. It has been frustrating trying to convince my colleagues to not satisfy the Wrogma in favor of evidence-based medicine. Nobody wants to admit they do not know everything about everything. People do not want to think ill of their mentors whose advice has in other aspects of their practice kept them out of trouble. Change is hard. But mostly, I think people close their mind off to learning a new area that they thought they understood. I think some people defensively are afraid that if they admit that this is an area they do not understand as well as they thought they did, then all of their prior judgments will be called into question and they might be open to ridicule, embarrassment, or legal challenges about practice. While I cannot speak to the first two, the third although, a real fear, is usually far more concerning and more enforceable as a breach of standard of care once you have been informed of the new insight and you continue to refuse to adapt and incorporate it. Nobody blames you for what you did not know, you get blamed for what you were told and refused to acknowledge. Sadly, going back to one of earlier points, change is hard. Getting people to admit what they do not know is maybe the biggest issue, but the fact that it is hard does mean it should not be done and rest assured I will continue to offer my insight to those who are interested, willing and motivated to hear it. Many of my patient who have suffered for years to decades with misdiagnosis and ineffective treatments, being told it is all in their heads, which has devastating psychological impact as well as continuing the disability that is limiting their lives. Too many of my patients have been helped by insight rather than ignorance for me to give up on treating the medical community for its lack of insight. Some patients have been scared away from medical treatment because of how they have been marginalized by people practicing Wrogma. I can only try to review the Wrogma with evidence-based medicine.