A common (about 5% of the population has one of the variants of this) congenital anomaly results less frequently in a progressive syndrome of back and/or leg pain. This syndrome involves the lower back, often but not exclusively on one side more than the other, and usually involves leg pain on that same affected side that may mimic a herniated lumbar disk. It affects any age group, but typically starts either in the thirties or in the older patient.
This condition results from the incomplete formation of the spine at the junction of the sacrum and the L5 vertebral body, and there is interface between the transverse process of L5 and the top of the ala of the sacrum (see diagram). This interface results in bone rubbing against bone but not with the benefit of a defined joint, but more like a broken bone that never healed properly. This also results in inflammation that can irritate the L5 nerve which runs past the point of interface, causing deformity or inflammation of the nerve and consequently pain.
This is often overlooked for many reasons: the typical MRI does not image this part of the spine well. The diagnosis is often overlooked, as the average radiologist or surgeon may just be looking for a herniated disk to be causing the pain. The patients do not respond to epidural steroids, and so are often written off as nothing being wrong with them, or that it’s all in their heads. In reality, there is a specific test to be performed that can identify with more than 90% accuracy, but this test needs to be done by someone with experience.
Surgical options include a minimally invasive shaving of the bones rubbing together, or a spinal fusion of the levels to prevent further movement of the bones against each other. Dr. Jenkins pioneered the minimally invasive treatment, and this has been shown to provide significant lasting relief.
For those who either are not candidates for the minimally invasive treatment, or for those who fail to improve with the minimally invasive treatment, spinal fusion is the next choice.
Chiari malformations (typically the Chiari I, there are 4 types but the type I represents more than 95% of all cases) can manifest as a complicated series of seemingly unrelated symptoms: weakness, numbness, pain, sometimes facial and eye symptoms, headaches, among others. Some patients are even misdiagnosed with fibromyalgia due to the diffuse nature of the symptoms [reference to my letter to JAMA regarding article on fibromyalgia].
The condition is caused by the compression of part of the brain, the cerebellar tonsils, which are the remnant of the part of the hind brain that used to control our tails, but no longer have any meaningful function. In patients with a Chiari malformation, the tonsils may be enlarged, or the skull may have developed not quite big enough to contain them and the rest of the brain, and they may be forced down into the opening at the bottom of the skull (foramen magnum) with the top of the spinal cord, causing compression of the spinal cord and diffuse symptoms.
This syndrome can be brought on in a patient previously without symptoms by an accident or injury, where the spinal cord is traumatized within the narrow confines of the anomaly, resulting often in much worse symptoms than would be expected by either the degree of the trauma, or the findings elsewhere in the spinal axis (since this is at the edge of the cervical MRI field of view, and many times the symptoms manifest themselves in the area of the thoracic spine, this diagnosis may be overlooked).
Treatment consists of a decompression of the foramen magnum and often the C1 lamina, called a suboccipital craniectomy with cervical laminectomy.
The treatment often includes expanding the space further by putting an expanding patch on the dura, called a duroplasty, and may also include shrinking the size of the tonsils so they do not exert pressure on the brain stem and spinal cord.
Spinal tethering is a general description of a combination of entities that all result in reduced freedom of movement of the spinal cord within the spinal canal due to some form of abnormal adhesion, scar, or membrane that causes local deformity or tension on the surface of the spinal cord. When the neurons that run in that portion of the spinal cord are deformed, stretched, or otherwise manipulated, they do not function normally. This may result in pain, numbness, weakness, or even changes to appear within the spinal cord known as a syrinx or syringomyelia (fluid within the spinal cord). When this condition manifests itself clinically (ie, the patient has symptoms related to the tethering), then release of the adhesions can result in improvement in neurololgical function, although this is very delicate and risky surgery in some cases.
Congenital – When the spinal cord is developing before we are born, there are a number of steps that may fail to develop normally. The spinal cord usually grows less than the spinal vertebral column over time, and the level at which the spinal cord ends and a tail of nerve roots (the cauda equina) begins rises from the lumbosacral area to stop somewhere between L2 at T12 in the vast majority of people. When the anchor line of the spinal cord, a fibrous band known as the filum terminale (the end string), is too thick or fails to stretch, the spinal cord fails to rise adequately, and remains under greater tension downwards. This can put tension on the brain stem as well as local nerves, and patients can have a wide spectrum of symptoms. In milder cases, these findings may present later, while more severe cases present in childhood or infancy.
Other types of congenital tethering include more serious congenital deformities like a diastematomyelia, or split cord anomaly, where a fibrous or bony structure passes through a hole in the middle of the spinal cord, and this band can act like the filum terminale to cause tension, neurological dysfunction, and pain. These need to be identified, and can cause scoliosis, weakness, or mimic other neurological syndromes. 5-10% of the time there is more than one, and the entire spine should be imaged if this diagnosis is suspected. The arrows point to the band, which was found to be partially calcified at surgery.
Post-traumatic – When the spinal cord is damaged as a result of trauma, there is often bruising or bleeding from the cord itself, either as a result of tearing of surface vessels by stretch, or by physical damage from bone fragments. This bleeding then can lead to scar formation between the spinal cord and the inner surface of the canal, known as the dura. When this scarring occurs, the deformity can cause further loss of neurological function or pain, often in a delayed fashion, sometimes 10-20 years later. When this occurs, the tethering can be cut so that the cord no longer is being tugged on with every movement of the body, and this can relieve or improve the symptoms. In this case, the patient had tethering anteriorly from the original fracture (blue arrow) and posteriorly as well (orange arrow).
Arachnoiditis – Surgery or other invasive treatments or events (myelograms, spinal anesthesia, “wet taps” with epidural procedures, infections, among others) can also intruduce blood or other forms of scarring into the spinal canal and lead to adhesions and often delayed dysfunction. This can lead to a condition known as arachnoiditis, or clumping of nerves from scarring together, either to the dura on the inside of the canal, or just together into a lump that causes local deformity and dysfunction. This tethering may be more difficulty to treat surgically, as there is very little to prevent the nerves from re-scarring together once separated. The normal anatomy on the right shows the nerve roots lining up with an even spacing in the canal, while the abnormal clumping, due to being shot in the hip and having bullet fragments spray the spinal canal, inducing bleeding and extensive scarring that caused the roots to clump in the middle.
Arachnoid cysts – These are usually a congenital anomaly, where an extra layer of an inner membrane within the spinal canal (the arachnoidal layer, so named because it has the apperance of being as fine as spider’s web) forms which becomes like a balloon that fills gradually over time and exerts both mass effect on the spinal cord as well as being a source of tethering of the spinal cord to the dura. These can be taken out relatively safely, but they can (about 10% of the time) come back.
In this case, the patient had leg weakness, and MRI had only a suggestion of something deforming the spinal cord and nerve roots (blue arrows) and slightly altered spinal fluid appearance behind the cord (which represented the fact that the spinal fluid in the cyst was not freely circulating like the rest of the spinal fluid (red arrows) A normal spinal cord image is shown to demonstrate the normal position of the cord and roots. A special test, the CT myelogram, showed that the dye did not initially communicate into the cyst (orange arrow). He improved from profound weakness and numbness in his legs to able to walk again without assistance by 4 months after surgery.
Neck and Back Pain
The management of neck and back pain (primarily neck and back pain, pain that radiates from either the neck or back down the arm, buttock, leg is considered under the herniated disk section) is complex and requires a thorough investigation into the primary pain generator. When tumors, fractures, and other intrinisic lesions have been eliminated, the likely diagnosis is one of arthritic or degenerative type instability in the disk or facet joints of the neck or back. This “micro-instability”, instability that is significant enough to cause pain worse with movement but not enough to be classified as gross or overt instability where the spine changes configurations with movement.
Treatment – Typically, this type of problem should be managed “conservatively”, or without surgery, until the problem gets so severe that surgery seems like a reasonable option. Typically, surgery involves removing or replacing the anatomic structures that are painful, aka the pain generator. Determining what the pain generator is needs to be the first step towards treating the problem, and this requires an extensive evaluation including physical examination, radiological studies, as well as in some cases interventional procedures to test various hypotheses in evolution (such as injections or procedures such as provocative discography). Dr. Jenkins works extensively with specialists in multiple areas to identify and treat these problems.
Finally, if all reasonable conservative treatments have been exhausted, surgical options may be considered. These may include decompressions, fusions, artificial disk or joint replacement, placement of a dorsal column stimulator or an intrathecal pump, a deformity correction, or other interventions. Sometimes, “expectant observation” is an active treatment, allowing a condition to develop more clearly so that an accurate diagnosis can be made. In any case, the treatment and surgical evaluations will be made in an ongoing manner, until Dr. Jenkins feels that he has nothing further to offer. But he has a wide range of tools to help, and is willing to take on patients whom other doctors have either given up on or have already operated on and require a revision.
Infections of the spine may result in weakness, pain, instability, and if untreated or not treated in time, even death. These are often an emergency, such as diskitis or meningitis, or at least require treatment urgently (such as with osteomyelitis, or bone infection). Understanding the condition, including the urgency to intervene to prevent further neurological or biomechanical damage, is critical to protecting the patient and improving their chances of getting back to a normal life.
Non-spinal conditions that mimic spinal disorders:
Piriformis Syndrome – Condition where the sciatic nerve is compressed by a small muscle in the hip, the piriformis muscle, and causes a syndrome similar to sciatica that may mimic a disk herniation. Treatment is usually stretching exercises tailored to this condition, and in rare circumstances, cutting part or all of this muscle to release the tension.
Other Common Entrapment Neuropathies
- Carpal Tunnel Syndrome
- Cubital Tunnel Syndrome
- Tarsal Tunnel Syndrome
- Suprascapular nerve entrapment
- Thoracic Outlet Syndrome
- Hip arthritis,
- knee problems,
- hip fracture,
- shoulder problems, rib fractures
- Bladder or kidney infections
- Blood clots in the legs (deep venous thrombosis, or DVT)
- Paraneoplastic syndrome
- Multiple Sclerosis
- Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)
- Peripheral neuropathies
Endometriosis of the retroperitoneum – Pain in the leg and back, but with a significant variation with menstrual cycles, does not respond to spinal interventions but require treatment by a gynecologist with experience with endometriosus