Overview: Head-neck-joint instabilities
From Head-neck-joints instability conditions
Table of contents Available documents from the overview:
- All-in-one document about Head-neck-joint instabilities
Contents |
The Cervical spine
Overview
The cervical spine is the most flexible, but also the weakest part of the entire spinal column. It is divided in
- the “classic” cervical spine with five parts (C3-C7)
- the head joint area consisting of the Atlas (C1)
- the Axis (C2) and the moving segment C2/3
The head joint area
The head joint area is composed of the upper and lower head joint. The upper joint (Articulatio atlantooccipipitalis) is made up of the first cervical vertebra, the atlas (C1) and the articular surfaces of the occipital bone. The atlas is the only vertebra without a body. On the other hand this vertebra shows so-called outgrowths (Massa lateralis) on the right and left side which can be seen in the picture on the right with the blue kidney-shaped areas.
Atlas
These outgrowths are connected via the front and rear atlas arch. The top of the outgrowths are formed by two sockets that are brought into contact with the so-called “condyles” of the occipital bone. The articular surfaces do not match exactly, which gives us the possibility to perform nodding (max. 30 degrees) and lateral declines (less than 20 degrees). You can say that the atlas “carries” the head, as the giant Atlas from Greek mythology carried the firmament on his shoulders. He also gave the vertebra its name. The atlas has to support the weight of the head with up to 7 kilograms.
Axis
The axis is the second vertebra, also called C2, and it forms the lower head joint (Articulatio atlantoaxialis). The Axis is specialised on rotational movements. Thereby the round sockets at the bottom of the atlas get into contact with the corresponding articular surfaces of the axis. The axis already has a vertebral body and an arch, as well as strong transverse and spinal processes. The most outstanding characteristic of the axis is its dens axis. The dens is a strong outgrowth to the top and reaches up to the atlas. At its front side it is covered with cartilage and shows a flat socket on the inner side the atlas.. The rear side, also covered with cartilage, slides on a stable transverse ligament (Ligamenta transversa) which is tightened between the two outgrowths of the atlas (see above picture). That way a hollow space (similar to a fissure) is created between the front atlas arch and the transverse ligament. In this space the dens can move and perform rotations of 15° to 25° to the left or right. Minor stretching and nodding movements are also possible because once again the lateral angular surfaces do not match exactly.
The head joint is very flexible since it is rather “loose”. Yet to prevent uncontrolled stretching, bending and turning movements from injuring the spinal cord, several ligaments inhibit the movement types in the head joint. The Membrana atlantooccipitalis anterior reaches from between the front atlas arch to the occipital bone. This ligament prevents excessive stretching in the upper head joint. There are three other important ligaments which can be seen in the adjacent illustration. These run in a V-shape from the dens to the front and lateral margin of the foramen occipitale magnum. The lateral ligaments are called Ligamenta alaria, the ligament in the middle is called Ligamenta cruciforme. These ligaments prohibit inordinate turning and tilting movements in the lower head joint.
The classical Cervical Spine
- The classical cervical spine consists of five vertebrae C3 to C7
The vertebrae do largely have the typical basic vertebral form, but they can be recognized by the Foramina transversaria as cervical vertebrae (this is a kind of canal for arteries). The cervical vertebrae are smaller compared to the ones of the remaining spinal column, increasing their size from cranial (top) to caudal (bottom). They are also diagonally wider than from the front to the rear. The upper front surface of the vertebra is formed like a scoop. The margins of this area are accumulated, which is called Uncus corporis, the bottom however is bevelled and crenated. From time to time there are small outgrowths of bones coming from the Uncus corporis which can exercise pressure on the respective spinal nerves. The cervical holes are rather large because they absorb the cervical intumescence of the spinal cord (Intumenscentia cervicalis). With its upper process, also called Facies articularis superior, each cervical vertebra is in contact with the lower angular process of the vertebra above. That way the vertebral canal of the cervical spine is formed, which is as well known as Foramina intervertebralia.
The 7th cervical vertebra (Vertebra prominens) stands a bit apart from the other cervical vertebrae. Its very long spinal process ends in a distinct hunch. This hunch can be palpated quite easily at the lower end of the neck furrow. The 7th cervical vertebra sometimes lacks the Foramen transversarium on one or both sides.
The cervical spine accommodates as well part of the spinal cord, namely 8 spinal cord segments (cervical segments) that supply especially the respiratory musculature and the upper extremities.. Arterienverlauf in der HWS und im KopfBut not only nerve cords run through the cervical spine, there are also arteries using it as a “canal”. The most important arteries here are the two Arteria vertebralis. Both arteries emanate from the Arteria subclavia (Arteria is the Latin word for artery) and pass on the left and right of the cervical spine through the Foramina transversi (plural form of Foramina transversaria) of the 6th to the 2nd cervical vertebrae. After the passage through the 2nd vertebra each artery makes a dorsal bend (to the rear) and runs on the rear atlas arch, this is the atlas loop of the artery. Then the arteries enter the cranial cavity and then continue forward again (cranial). Both Arteria vertebralis merge into the Arteria basilaris.
These arteries supply the cerebellum, parts of the mesencephalon and of the brain stem, furthermore hearing and equilibrium organs and rear components of the cerebrum as well as cervical spinal nerves and ganglia (nerve roots). It has to be noticed that the artery has very little expansibility.
I hope I was able to explain you a bit the sophisticated and complicated structure of the cervical spine. In my opinion, these explanations are important in order to understand the consequences that injuries of the cervical spine can implicate. Unfortunately injuries of the cervical spine do often occur in our engineered world, just think of the whiplash injury.
Diseases of the cervical spine
As can be seen at the anatomical remarks, the spinal column is a structure built in a rather complex way. It does not only contain bones and intervertebral discs, but also nerve tracts (spinal cord), arteries and even structures similar to sense organs, if one takes a look at the construction of the head joint. Due to accidents and also signs of wear with increasing age, injuries or deformations at the spinal column can now occur, causing certain discomfort. Generally it can be said that a very high percentage of disturbances at the spinal column is to be traced back to displacements of vertebrae or intervertebral discs. This leads to irritations of the nervous system. One can imagine this easily by keeping in mind that the spinal column is a canal of 26 elements containing the spinal cord like a thick cable with many lines. If now an element jumps out of the canal, a “kink” results.
At the kink the diameter of the canal is now also smaller, and so in the kink the cable is pressed on the walls of the canal. That way the cable is squeezed, which can be intensified or also reduced by a movement of the body. Squeezed cables provoke temporary malfunctions, either they conduct electric current or they do not. That is also called a loose connection. This is similar to the spinal cord: Certain nerves are either completely squeezed and thus “deactivated” at the vertebral dislocation, or they are only temporarily squeezed, depending on how the body is moved.
As we already know, there are spinal cord segments that correspond to the vertebrae and that exercise certain functions. If now a vertebra dislocates, its corresponding spinal cord segment is irritated (“squeezed”), which can lead to different consequences depending on the segment. Also here there are overviews by chiropractors that I display for the sake of completeness:
Cervical Spine
C1 Function: Blood supply of head, pituitary gland, scalp and facial bones. Inner and middle ear. Sympathetic nerve system. Consequences: Headache, nervousness, sleeplessness, influenza encephalitis, high blood pressure, migraine, nervous breakdown, amnesia, chronic fatigue, dizziness
C2 Eyes, optic nerves, acoustic nerves, sinuses, mastoid processes, tongue, forehead Sinus disorders, allergies, strabismus, deafness, eye complaints, earache, faints, certain kinds of blindness
C3 Cheeks, auricles, facial bones, teeth, facial nerve Neuralgia, neuritis, acne or pimples, eczema
C4 Nose, lips, mouth, Eustachian tube Allergic coryza, catarrh, loss of hearing, adenoids
C5 Vocal chords, neck glands, throat Laryngitis, hoarseness, sore throat, throat quinsy
C6 Neck musculature, shoulders, tonsils stiff neck, pain in the upper arms, tonsillitis, pertussis, croup cough
C7 Thyroid gland, shoulder bursa, elbows Bursitis, colds, diseases of the thyroid gland
But this list does not mean that a suffering is always due to a dislocated vertebra. If you suffer e.g. from chronic asthma, which was diagnosed without doubt by a colleague of internal medicine, then this has very probably a different cause than a “tilted” first thoracic vertebra. But if you have e.g. pain in the forearm and the orthopaedic or neurological examinations did not result in a statement, then you should possibly ask your doctor to examine the spinal column. It is indeed possible that the cause is an already slightly displaced first thoracic vertebra and the nerve segment of the spinal cord irritated by it. It is absolutely imaginable that this cause is then rapidly removed by massages or other suitable therapies.
Of course not all problems of the spinal column can be corrected by simple means. Vertebral fractures and instabilities require a more exact diagnosis and mostly a surgical intervention.
In the menu items of this page the most important diseases of the individual spinal column sections and their therapy are briefly addressed. A comprehensive consultation and diagnosis of the individual disorders is only possible with an ambulatory presentation.
Degeneration
Beyond the age of 30, degeneration in the area of the intervertebral discs of the human cervical spine already begins.
The cervical vertebra is in no way only a hosting organ for the spinal cord and its nerves. I rather consider the cervical vertebrae to be a multifunctional organ consisting of 7 cervical vertebrae, ligaments and attachment mechanisms, intervertebral discs and multiple joints. Taking into account the balance of the head, it can quasi be referred to as a sense organ.
Of course dysfunctions, signs of wear and changes due to accidents can cause various symptoms of discomfort that do not necessarily always involve neurological dysfunctions. Mostly the practice of a specialist on the spinal column is frequented by patients who have chronic discomfort due to a more or less strong wear in the cervical spine area. The loss of humidity in the intervertebral discs causes a wear, coming along with a change in the geometry of the single joints or of the cervical spine’s posture. Generally, one speaks of an arthrosis of the cervical spine.
In former times and also nowadays these patients are often accompanied with the half-way consolatory advice: “It is a sign of wear, it is about arthrosis and you have to live with it.”
With today’s modern medicine and the technological possibilities, one does not have to live with this pain. There is absolutely an acceptable surgical possibility to restore the modified geometry of the cervical spine to a large extent and thus to improve life quality. It is not a matter of dangerous surgery at the cervical spine, as commonly believed, rather of precision surgery that normally does not take more than 1 – 2 hours and that is done without a loss of blood. Normally patients experience an improvement of life quality immediately after surgery, overall discomfort decreases considerably. In those cases the stay in hospital is about 10 days, patients are being mobilized already 12 hours after surgery. Usually a subsequent therapy of 3 weeks is also recommended.
Primarily, conditions for identifying the necessity of such a surgery are:
- patients’ chronic discomfort which resists therapy,
- a clinical examination finding created in ambulance,
- X-ray examination of the cervical spine in the usual manner,
- special functional examination of the cervical spine’s course of motions in an image converter, and finally
- an examination of the cervical spine with magnetic resonance imaging.
Especially with patients who have already undergone one or two surgeries in the area of the cervical spine with insufficient therapy success, the exact information about details should practically take place during an ambulatory presentation.
Diagnosis of head-neck-joint instabilities
Introduction
In the industrialised world we nowadays live in, a lot of accidents happen, partly due to heavy traffic, partly due to the mechanised work environment. An accident can certainly cause injuries of the bones, vertebral bodies or parts thereof, but it can also lead to torn or overexpanded ligaments with corresponding after-effects.
Probably the best-known and most controversial injury is the whiplash injury, called “distortion of the cervical spine” by physicians. In fact this means that no impact of the head is involved in it. But due to modern car technology (headrests) a head impact mostly occurs. The collision forces do not necessarily have to leave external damages on the head, rather they lead to compact brain injuries. In lethal cases, which appear seldom, greater bleedings of the head callosity can be found during the post mortem examination, even though no injuries can be seen from the outside. Then a whiplash injury by a rear impact accident with a compact brain injury is not an absolute whiplash injury. But also an absolute whiplash injury without head impact can lead to cerebral injuries. This could be proved in 1968 by Ommaya et al. in an experiment with monkeys. So a whiplash injury is a “distortion of the cervical spine with or without cerebral involvement”. According to the Quebec Task Force on Whiplash-Associated Disorders (Spitzer et al. 1995), peripheral disorders such as pain or stiffness in the neck and cerebral disorders such as headache, dizziness, hearing dysfunctions, ringing in the ears (tinnitus), concentration and memory disorders, deglutition dysfunctions and temporomandibular dysfuncions (functional disturbances in the area of the lower jaw at the passage to the temple) are symptomatic. A fibrillating or blurred sense of vision also appear frequently. These symptoms appear with a characteristic latency (time delay) of 0 to 72 hours. The cerebral symptoms mentioned above are relevant in order to chronify a disease. Unfortunately just these symptoms provoke heavy controversies among physicians during the assessment of the connection with the accident (causality). A whiplash injury can emerge almost everywhere: During a traffic accident, while doing sports or at work. Yes, it can even happen while skiing or in an airplane, although it has to be said that car accidents are by far the most frequent reason for a whiplash injury. The critical factor for the occurrence of a whiplash injury is not the place, but the mechanism of the accident, i.e. the body has to perform the movement of a whip stroke. The exact course of such a whip movement during a rear-end collision can be seen in the subchapter. The common diagnostic method with a whiplash injury of the cervical spine is shown in the adjacent diagram and can be looked up in appropriate medical literature. But there are examinations that are generally less known in the emergency departments of hospitals: First, the determination of the brain’s state is mostly missing, even though the appearance of the symptoms mentioned above indicate a damage. Second, the examination of the passage from head to neck is missing. And also the next problem appears here: The possible injuries of the brain, of the passage from head to neck and also of the jaw area (see above) need an interdisciplinary treatment. Thus, depending on the severity of the case specialists from orthopaedics, neurology, ENT medicine, maxillary surgery and neurosurgery would have to cooperate in the creation of a diagnosis and the corresponding treatment. Mostly a whiplash injury is only treated from the point of view of an orthopaedist. This may be sufficient in light cases of the whiplash injury. However, if the patient’s discomfort does not ease, examinations by the specialists mentioned above to clarify the circumstance would immediately have to be ordered. And this is mostly not done, with fatal consequences for the patient, so that irreparable damage can possibly result.
Injuries at the passage from head to neck
With a whiplash injury, the cervical spine is over-expanded. But not every “whip stroke” happens in the exact “nodding axis of the head”. If you collide with an obstacle e.g. by car in a rather lateral way, or if cars collide on a crossing, then it is absolutely possible that the whip stroke is triggered a little displaced from the normal nodding axis and that it includes a kind of “head shaking”. So it is indeed possible that twists also occur in the cervical spine.
And not only this: We know from the cervical spine’s anatomy that the cervical spine has a network of ligaments and arteries. Furthermore there is a joint connection (head joint) between the Atlas (C1) and the Axis (C2). This is the most flexible, but also the most unstable part of the spinal column. The Dens is a kind of “buttress” and prevents the head from over-flexion. All other movements like head shaking, nodding, turning the head etc. are secured by the ligaments and capsules. In a whiplash injury sometimes a rather violent and not consciously controllable over-flexion of the head occurred. That way it is possible that the head joint consisting of Atlas and Axis is “opened” more than its anatomical limits allow. Exactly this opening has to be prevented on the Axis by the three ligaments Ligamenta alaria right and left and Ligamenta cruciforme, as well as the Membrana atlantooccipitalis anterior on the Atlas, and they can now at least be over-expanded, but also be partially or completely torn. There is another ligament that can be abnormally expanded or torn apart: the Ligamenta transversum. This ligament prevents the Dens from touching the spinal cord. A “simple” over-expansion or twist of the cervical spine is normally cured after about six weeks, a ligament injury is not. And this is exactly where in my opinion an unnecessary and sometimes vehement discussion among physicians begins that is too often carried out to the patient’s disadvantage. The latter will hear an opinion from one doctor and from the other one a different opinion again. Why? The solution of the mystery lies in the exact examination of the patient’s passage from neck to head. Some physicians think that a whiplash injury is a rather light injury. If a damage of the cervical spine were existent, it would be visible on the X-ray images. If there is none, then it is just a whiplash injury. The other physicians have the point of view that the cervical spine can not only become injured in the middle section, but that the head joint and/or the ligaments can also be injured and that this has to be examined. How can an injury at the passage from neck to head be determined then?
Diagnosis of head-neck-joint instabilities
Patients with a whiplash injury of the cervical spine that does not involve an osseous injury or the injury of nerval structures face the problem that these patients are examined by accident surgeons, orthopaedists etc. and that normal X-ray images are made for the examination. These images naturally do not indicate changes of the cervical vertebrae resp. of the affected section since normally a static image is taken.
This situation applies also to modern examination, like e.g. computed tomography or magnetic resonance imaging because these are not functional examinations. With a patient lying still, of course no torn ligaments can be detected. This can be compared with a tear-off of the ligaments at the knee-joint. If the knee-joint ligaments are torn, the patient is not capable of walking. But the X-ray images performed while lying do not result in an abnormal statement. If the knee and also the entire leg were examined by a neurologist because the patient could not walk, then no neurological changes at all would be recognizable here either. But if a stress image of this knee-joint, i.e. a functional one, is taken, a dysfunction of the knee-joint, that is, the enlargement of the knee-joint gap in an abnormal form, can immediately be determined and documented. So the conclusion can be drawn that the ligament on the knee-joint or on the ankle must be injured, since otherwise the gap at the joint would not allow such a wide spread. Equally, a ligament injury on the cervical spine cannot be proved because most of the produced X-ray and MRI images are not done functionally.
I would like to demonstrate this to you with anonymous X-ray images: Here you see X-ray images, on the right an X-ray image from the front, on the left a lateral view, that were both taken with a C-arm X-ray machine. No injury can be seen at all. You can say that there is no osseous injury. Nevertheless the patient suffered from all the disorders already mentioned above: headache, decrease of memory, partial signs of paralysis, prickle in the arms or legs, frequent dizziness, ringing in the ears, dysfunctions and pain in the area of the jaw joints, of the ears and eyes. With a C-arm X-ray machine, we now create a functional image from the front through the open mouth. Thereby the head is tilted a bit to the front and to the side. The image can be seen on the right. No osseous injury can be recognized. You can see the Dens, the characteristic of the Axis as the second scervical vertebra. According to anatomy, the Atlas as the first vertebra lies around the Dens. In the image below the contours of the two vertebrae have been emphasized. And now something noticeable can be discovered: Between the Dens and the Atlas Funktionelle Aufnahmethere is a hollow space, as described on the anatomy page of the cervical spine.
The ligaments on the Axis and the Atlas hold the head joint in a way that there is always a gap with constant dimensions between Dens and Atlas. If now the respective regions on the X-ray image are examined more closely, it can be noticed that the gaps on the right and left of the Dens are asymmetric! The left gap is wider. Similar to the knee-joint you can now conclude from this image that here a ligament injury on the left side is existent. Due to the relatively wide gap on the left it can be assumed that the left lateral ligament (Lig. alaria left) is torn.
That means there is a so-called instability at the craniocervical passage which causes the disorders already mentioned above. Of course this diagnosis can still be confirmed by a functional MRI or CT.
In this case an adequate operation for stabilization can help. The patients with an instability at the passage from head to neck often show the symptoms already mentioned like headache, decrease of memory, partial signs of paralysis, prickle in the arms or legs, frequent dizziness, ringing in the ears, dysfunctions and pain in the area of the jaw joints, of the ears and eyes. These symptoms confirm the suspicion of a structural instability of the passage from head to neck. In order to judge these symptoms better, we have developed a form in which the patient can describe his disorders. That way I am also able to determine changes of the symptoms in the course of time.
Complying with the anamnesis and a whiplash injury the necessary examinations as described and finally the necessary operations can be done.
In the area of the middle cervical vertebrae (from the 2nd cervical vertebra up to and including the 1st thoracic vertebra) fractures can of course occur after accidents, but also over-expansions, dysfunctions or even injuries of the intervertebral discs and the corresponding ligaments, which happens very frequently. The patients complain about permanent pain in the neck, in the shoulder-neck area, also about pain in the neck and back of the head that increase substantially during stress. They can also temporarily involve pain in the arms or prickle. If a whiplash injury of the cervical spine with the mentioned symptoms is existent that does not become better with conservative treatment, a conversation and an examination appointment is advisable, since with the special examination procedure where the cervical vertebrae are examined in motion, such instabilities (like e.g. also at the knee-joint) can be recognized and the necessary stabilizing operation can finally be done.
A whiplash injury can also cause similar damage in the area of the lumbar spine which can then be clarified and treated the same way.
Operational intervention, surgery
The surgical method
With a craniocervical passage that has become unstable through torn ligaments or over-expansion after an accident, the aim of the operation is a stabilisation. Since up to now it is not possible to restore the original state in a way that the torn Ligamentum alare or the ruptured (partially torn) Ligamentum transversus atlantis be replaced ventrally – i.e. from the front -, the only remaining method is the stabilising operation at the craniocervical passage in a dorsal way, i.e. from the rear.
The surgical technique
Patients are operated in general anaesthesia. The bearing takes place in a face-down position, with the head a little ventrally bent (slightly bent forward) supported on a headrest. The image converter is already integrated and aseptically covered. The incision (surgical cut) is carried out in the middle line in the area of the craniocervical passage. After the incision over the spinal processes the relocation of the paravertebral musculature is effected - the rear musculature at the cervical spine is put aside -, as well as the attachment of spreaders. With that, the surgical field has been reached. Now the motion sequence at the passage from neck to head is observed. By moving the head during the open operation situs it can very well be determined to which extent the single ligaments lying ventrally (in the front) function and how far a disharmonious motion sequence at single vertebral bodies is visible. Furthermore it is possible to gain insight in the area of the articular capsule C1/C2 and thus to assess it intra-operatively. With all operated patients the instability determined before surgery proved true during surgery as well. However, different consequences of injuries could be detected, mostly a combined instability between the vertebrae C0/C1, C1/C2 and C2/C3, with C0 being the occipital bone. In many cases a rotatory luxation , Stabilisierungsoperation (wrench) or subluxation between C1 and C2 had additionally occurred. Under the control of the image converter an ideal physiological position of the upper cervical vertebral joints is adjusted. The position of the head compared to the neck is also taken into account. From the C2 vertebral arch towards the Massa lateralis of C1, a drilling is performed, and at first titanium screws are temporarily placed with compression. This screw connection leads to an immediate stabilisation between C1/C2. Afterwards, a titanium plate is bent according to the anatomy at the craniocervical passage, so that a screw connection of the plate at C0, C1, C2 to C3 is possible. This titanium plate is attached at the occipital bone with very short screws after a corresponding, careful spot drilling of the skull bone. In the middle the transarticular C1/C2 screw is fastened, which mostly requires a screw with 40 mm of length. This screw also stabilizes the C1/C2 joint.
Furthermore the small vertebral joint C3 is still included in the stabilisation with the plate. This way a fixed entity between C0/C1/C2 up to and including C3 is created which does not allow any abnormal movements. After inserting a Redon drainage the neck musculature is then again completely sewed on the spinal processes in the middle line. Not until that is the wound sewed in layers and bandaged.
The result of the operation
After the operation, 85% of all patients reported a significant improvement of their disorders. A clear decrease in headache, dizziness symptoms and ringing in the ears could be noticed. At the moment, the crucial factor seems to be the time between trauma and surgical treatment. The shorter the discomfort lasted, the more positive were patients’ reactions to the operation result
X-ray image of the cervical spine after the operation (the titanium plates can be recognized) A small improvement can be registered in concentration capability and the loss of power. Of course such a stabilisation at the cervical spine also has consequences: A clear limitation in mobility of 75% in all levels remains in the entire cervical spine. This limitation is individually different and was until now mostly well tolerated by the patients since the disorders already mentioned had clearly decreased. The permanent medication with analgesics before the operation is clearly reduced. The pain reduction after the operation was specified by the patients at 70 – 80%. According to the patients, especially daily activities are to a large extent possible again after the operation. 20% of the patients can exercise a profession again. Only with 5% of the patients the expectations in the operation were not fulfilled at all.
Surgery overview
This successful surgery was done in Germany.
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |