Axial tooth fractures and dislocations in the atlanto-axial joint region

The normal relationship between the atlas and axis in the "pivot" joint can be disrupted if:

• as a result of the violence, a fracture of the axis tooth will occur and the head, atlas and broken axis tooth will shift forward or backward as a single block;
• as a result of the violence, the transverse ligament of the atlas will be torn and the head and atlas will be displaced forward;
• the axis tooth, under the force of the force, will slip out from under the transverse ligament of the atlas and shift backwards.

It is known that the boundary between the medulla oblongata and the spinal cord is located in the plane passing through the middle of the anterior arch of the atlas and the upper edge of its posterior arch. At this level, the sagittal diameter of the spinal canal is 25-30 mm, and the anterior-posterior diameter of the bulbar neck is 10-12 mm. However, the presence of a fairly massive and complex ligamentous apparatus in this area significantly reduces the spare space between the brain and the bony walls of the spinal canal, so a displacement of the atlas over the axis of 10 mm is sufficient for brain damage to occur. These data exhaustively characterize the danger of the above injuries.

Kienbock differentiates between transdental, transligamentary and peridental dislocations of the atlas. Transdental dislocations of the atlas according to Kienbock are actually fracture-dislocations, since the displacement of the head, atlas and odontoid axis occurs due to a fracture of the odontoid. Transligamentary and peridental dislocations of the atlas according to Kienbock are true dislocations, since they occur as a result of either a rupture of the transverse ligament of the atlas or slippage of the odontoid axis under an unruptured transverse ligament.

In the last decade, there has been an increase in the number of patients with odontoid fractures. This is due to an increase in cases of severe transport trauma and improvements in X-ray diagnostics. According to a number of authors (Nachamson; Jahna; Ramadier; Bombart; Gomez-Gonzales, Casasbuenas), odontoid fractures account for 10-15% of all cervical spine injuries and 1-2% of all spine injuries,

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Causes of axis tooth fracture and displacement in the atlantoaxial joint area

Traumatic displacement of the atlas due to a fracture of the odontoid axis may occur both anteriorly and posteriorly. Anterior displacements are much more common. The severity of this injury depends on the degree of displacement of the first cervical vertebra and, consequently, the nature of the spinal cord injury. The injury occurs with an indirect mechanism of violence, most often as a result of a fall on the head. With a flexor mechanism of injury, an anterior displacement of the atlas occurs, with an extension mechanism - posterior. A fracture of the odontoid axis with displacement of the atlas may also occur with inadequate violence in cases of insufficient strength and increased fragility of the tooth, which are observed with partial preservation of the basal cartilaginous plate of the tooth.

Symptoms of axis tooth fracture and displacement in the atlantoaxial joint area

The symptoms of a fracture of the axis odontoid and displacement in the area of the atlantoaxial articulation are quite variable and can range from mild pain during neck and head movements, pain during swallowing (anterior displacement) to instant death at the scene of the accident. This ultimately depends on the degree of displacement of the atlas above the axis. Three degrees of anterior displacement of the atlas should be distinguished, which give rise to different clinical courses of this injury.

First degree of displacement. The fracture of the axis tooth is not accompanied by any displacement of it, and therefore, there is no displacement of the atlas and head over the axis. In the absence of a pronounced concussion, the victim does not lose consciousness. Mild pain when moving the head and neck, a feeling of discomfort in the neck area quickly pass. The victim does not understand the misfortune that has happened, and the doctor may underestimate the nature of the injury. This apparent well-being is very relative. Bone fusion in the fracture area often does not occur at all or occurs extremely slowly. Subsequent minimal trauma can lead to an irreparable catastrophe. In the figurative expression of Nguyen Quoc Anh, such a person "walks next to death."

The second degree of displacement. With an average value of traumatic force, which leads to a fracture of the axis tooth, the atlas, which is displaced forward, together with the broken axis tooth and the head, is held on the lower part of the articular bevel of the second cervical vertebra, i.e. a subluxation occurs. Clinically, this is manifested by a fainting state of varying duration, sometimes by loss of consciousness. When consciousness returns, the victim complains of pain when trying to straighten the neck, pain in the back of the head, in the upper cervical region. Neurological disorders are revealed in the form of pain in the innervation zone of the greater occipital nerve, along the underlying cervical roots, monoplegia, diplegia, hemplegia, spasticity. When trying to raise the head, medullary compression syndrome occurs, which occurs due to pressure of the posterior arch of the atlas on the brainstem.

The resultant vertical force of gravity, represented by the weight of the head, is decomposed into two component forces: one of them passes through the plane of the fracture and is directed downwards and backwards, giving the cervical spine a position of extension, the second is directed forwards and downwards and tends to lift the back of the head, and with it the posterior arch of the atlas. This leads to the fact that as soon as the victim tries to lift his head, the bulbomedullary part of the brain is subjected to compression, which leads to the occurrence of the syndrome mentioned above.

Third degree of displacement. In case of severe violence and occurrence of a fracture of the axis tooth, the head and atlas together with the broken tooth slide along the anterior bevel of the articular surfaces of the second cervical vertebra - a complete dislocation occurs. The posterior arch of the atlas, moving forward, compresses and damages the brain at the border between the medulla oblongata and the spinal cord. Death occurs from instant "decapitation" of a person.

If in the second and third degree of fracture-dislocation of the I-II cervical vertebrae, which arose as a result of a fracture of the axis odontoid, a sufficiently bright and pronounced clinical picture allows one to suspect this injury, then fractures of the axis odontoid without displacement, due to the mildness of clinical manifestations and apparent well-being, can mislead the doctor and remain unrecognized in time. Insufficient or incorrect treatment of these victims conceals serious, sometimes irreparable consequences.

Diagnosis of axis tooth fracture and displacement in the atlantoaxial joint area

X-ray examination is invaluable for clarifying the nature and degree of atlas displacement. It allows one to correctly assess the nature of the injury, the features of vertebral displacement, the presence or absence of concomitant rotational subluxation of the atlas, which may occur with these injuries. The X-ray method is of decisive importance in diagnosing a fracture of the axis tooth without displacement. A correctly performed profile X-ray allows one to identify all the changes that have arisen as a result of the injury; in some cases, tomography is useful for greater detailing of the existing changes. A transoral image allows one to clarify the condition of the posterior arch of the atlas, the presence or absence of its rotational subluxation. The more pronounced the degree of displacement of the broken tooth, the more shortened it appears on the posterior transoral X-ray.

It is not always easy and simple to confirm or reject the presence of a tooth fracture without displacement, especially in recent cases. If it is impossible to establish an accurate diagnosis, the victim should be treated as a patient with a fracture, and after 2-3 weeks, the X-ray examination should be repeated. The appearance of a narrow line of enlightenment, especially if it is emphasized by adjacent areas of irregular sclerosis, makes the presumptive diagnosis reliable.

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Treatment of axis tooth fracture and displacement in the atlantoaxial joint area

Examination and transportation of the victim must be carried out with extreme care and caution. In the process of careless examination and transportation of a fractured axis tooth without displacement, secondary displacement of the atlas and head may occur and cause compression or damage to the brain. Symptomatic drug treatment is carried out according to indications. The victim is put to bed in a supine position. In the absence of displacement and concomitant severe injuries, a craniothoracic plaster cast is applied, which is replaced with a removable corset after 6-8-10 months. External immobilization is stopped only when there is confidence in the onset of bone fusion. Otherwise, the patient is forced to either constantly use an orthopedic corset or undergo occipitospondylodesis (occipitocervical arthrodesis).

If there is a displacement of a broken tooth, it is necessary to eliminate the existing subluxation or dislocation (!) and align the fragments of the broken tooth. This is achieved either by manual reduction, which is only permissible in experienced hands, or by reduction using traction (skeletal traction by the bones of the cranial vault, Glisson's loop). In both cases, the doctor is required to have a clear idea of the nature of the damage and displacement of the fragments, the ability to visualize the relative positions of the displaced vertebrae and their relationship to the spinal cord.

Anesthesia is not used. Manipulations during reduction depend on the nature of the displacement: in case of anterior subluxations, lengthwise stretching and extension of the head are performed, in case of posterior displacements - lengthwise stretching and flexion. All manipulations are performed under X-ray control. Manual reduction requires certain skills from the doctor. Upon achieving reduction manually or by traction, a craniothoracic plaster cast is applied and subsequent treatment is carried out in the same way as for fractures without displacement, if there are no indications for more active intervention (revision, decompression) from the spinal cord.

Occipitospondylodesis is an operation that involves creating a posterior bone block between the occipital bone and the upper cervical spine using bone grafting.

The first report of an occipitospondylodesis operation in the literature available to us belongs to Forster (1927), who used a bone pin from the fibula to stabilize the upper cervical spine in progressive atlantoaxial dislocation after a fracture of the odontoid 2 of the cervical vertebra.

Juvara and Dimitriu (1928) attempted this operation on a patient with tetraplegia; the patient died. Kahn and Iglessia (1935) were the first to use a graft from the iliac wing crest to stabilize the spine in a patient with atlantoaxial subluxation after a fracture of the axis odontoid and unsuccessful conservative treatment. Rand (1944) performed this operation on a patient with spontaneous subluxation of the atlas. Spillane, Pallisa, and Jones (1957) reported 27 similar operations performed for various indications. An operation performed as a total cervical spondylodesis was reported in 1959 by Perry and Nicel, who performed it on a patient with severe paralysis of the cervicoccipital muscles resulting from poliomyelitis. We performed this operation in our own modification on a patient with a fracture of the roots of the arches of the second cervical vertebra (Ya. L. Tsivyan, 1963). Hamblen (1967) published 7 of his observations. I. M. Irger (1968) described his method of occipitocervical arthrodesis, performed on 3 patients.

It should be emphasized that fractures and fracture-dislocations of the axis tooth are among the cervical spine injuries that are dangerous for the victim and difficult to treat. The danger of these injuries is due to the possibility of damage to the brain stem and upper spinal cord, severe concussions and brain contusions. Even with primarily uncomplicated injuries, secondary brain damage can easily occur:

Regardless of whether there is a complicated or uncomplicated injury to the two upper cervical vertebrae, the result of the undertaken surgical intervention should be reliable internal fixation of the damaged section. If, based on clinical data or during the surgical intervention, there is no need to revise the contents of the spinal canal, the task of the surgical intervention is to reposition the displaced fragments and reliably immobilize them. If, based on clinical data or during the surgical intervention, there is a need to revise the contents of the spinal canal, then the above-mentioned tasks are supplemented by the additional need for surgical treatment of the damaged elements of the spinal cord and the elimination of its compression. Reliable internal fixation in case of injury to the two upper cervical vertebrae can be achieved using occipitospondylodesis.

Indications: recent injuries of the two upper cervical vertebrae, accompanied by instability of this part of the spine; progressive atlantoaxial subluxations after unsuccessful conservative treatment; some congenital anomalies of the upper cervical vertebrae, leading to instability of the spine; consequences of laminectomy and other interventions on the upper cervical vertebrae, causing instability of the spine; as a method of preventing instability in the upper cervical region in some tumor and destructive processes in the upper cervical vertebrae; severe paralysis of the cervical muscles.

Preoperative preparation. In case of fresh injuries - the fastest and most careful clinical, neurological and radiological examination possible. If indicated - appropriate drug treatment. It is necessary to treat the damaged cervical spine with care, reliably immobilize it; avoid unnecessary transfer and shifting of the victim. The victim's head should be clean-shaven.

The victim is placed on his back. The head is pulled along the long axis of the spine by the assistant's hands. The head is fixed by the assistant's hands continuously from the moment the victim arrives until skeletal traction is applied to the bones of the cranial vault. After intubation and the onset of anesthetic sleep, with continued skeletal traction along the axis of the spine with additional immobilization of the head, the assistant turns the victim onto his stomach. Oilcloth flat pillows are placed under the upper chest and forehead of the victim.

Anesthesia - endotracheal anesthesia with controlled breathing.

Occipitospondylodesis technique. The soft tissues are dissected layer by layer using a median linear incision from the occipital protuberance to the spinous process of the V-VI cervical vertebrae strictly along the midline. If the incision is not made strictly along the midline, but deviates to the side from the nuchal ligament, significant bleeding from the neck muscles is possible. The occipital bone is skeletonized subperiosteally from the occipital protuberance to the posterior edge of the foramen magnum and to the sides from it. Strictly subperiosteally, with maximum caution, the posterior arch of the atlas, spinous processes and arches of the required number of underlying cervical vertebrae are skeletonized. When skeletonizing the posterior arch of the atlas, special care should be taken not to damage the vertebral artery. Caution is also required because congenital underdevelopment of the posterior arch of the atlas or damage to it may occur. If the intervention is performed due to a fracture of the roots of the axis arches or there are concomitant injuries to the posterior sections of other vertebrae, then double caution should be exercised when skeletonizing the underlying vertebrae. In general, the arches of the cervical vertebrae are mobile, thin, and require delicate manipulation. Orientation in the posterior paravertebral tissues may be difficult due to their impregnation with old blood that has spilled out. In later interventions, separation of soft tissues from the arches is difficult due to the formed scar tissue. Profuse bleeding is stopped by tamponade of the wound with gauze napkins moistened with hot saline. The area of damage is examined. Depending on the presence or absence of indications, a revision of the contents of the spinal canal is performed with preliminary laminectomy or removal of the broken arch. In chronic cases, it may be necessary to resect the posterior edge of the foramen magnum and dissect the dura mater.

Actually, occipitospondylodesis can be performed in two variants. The first variant is limited to the application of a wire suture and is indicated only for fresh injuries. The second variant combines the application of a wire suture and bone grafting.

Option 1. 1 cm to the left and right of the middle of the occipital bone thickening formed by the inferior nuchal line, two parallel channels 1-1.5 cm long are drilled vertically in the thickness of the occipital bone with a 2 mm diameter drill. These channels pass in the thickness of the spongy bone between the outer compact plate and the vitreous plate of the occipital bone. A drip of the same diameter is drilled transversely through the base of the spinous process of the second or third cervical vertebra. A stainless steel wire with a diameter of 1.5-2 mm is passed through the channels in the occipital bone in the form of a U-shaped suture. One end of the passed wire is longer than the other. The long end of the wire suture is passed through the transverse channel at the base of the spinous process of the second or third cervical vertebra. The necessary positioning of the head is performed under visual control. The wire suture is tightened and firmly tied in the form of a figure eight. Hemostasis is performed. The wounds are sutured in layers. Antibiotics are administered. An aseptic bandage is applied. External immobilization is performed by skeletal traction for 6-8 days, followed by the application of a craniothoracic bandage. The applied wire suture eliminates the possibility of lifting the back of the head and thus protects the spinal cord from secondary compression.

This variant of occipitospondylodesis allows to quickly complete the surgical intervention. It achieves sufficiently reliable stability in the area of the damaged section of the spine. It is used when the surgical intervention cannot be delayed due to the circumstances that have arisen, when it is extremely undesirable to cause additional surgical trauma to the patient, when the nature of the injury allows to limit ourselves to such fixation. The disadvantages of this variant of the operation include the possibility of wire rupture and suture failure. When the victim is taken out of the threatened condition, if there are appropriate indications, it is possible to supplement the intervention with osteoplastic fixation in the second stage.

The second option, in addition to the application of a wire suture, immediately provides for additional osteoplastic fixation of the occipital bone and the damaged section of the spine. Depending on the indications for which the intervention is performed, in addition to the manipulations performed in the first option, the spinous processes and arches of the underlying cervical vertebrae are additionally skeletonized. Compact bone is carefully removed from the spinous processes and semi-arches until the underlying spongy bone is exposed. Two compact-spongy bone grafts taken from the tibia or the crest of the iliac wing are placed on the exposed spongy bone of the semi-arches on both sides of the bases of the spinous processes. The diameter of the bone grafts is 0.75-1 cm, their length should correspond to the length of the segment of the spine to be fixed from the outer surface of the occipital bone plus 0.75-1 cm. Both auto- and homografts can be used, which should be placed in such a way that their spongy surface is adjacent to the exposed spongiosa of the semi-arches and spinous processes. The proximal ends of the bone grafts rest against the occipital bone near the posterior edge of the foramen magnum. At the points of contact of the grafts with the occipital bone, grooves are formed using a milling cutter or small semicircular chisels, penetrating into the thickness of the spongy layer of the occipital bone. The proximal ends of the bone grafts are inserted into the grooves of the occipital bone, and the remaining, more distal part of the grafts is fixed to the arches of the cervical vertebrae using nylon or thin wire sutures. A kind of bone bridge is formed, which is thrown from the occipital bone to the cervical vertebrae. The bone wound is additionally filled with bone chips. If a laminectomy was performed, bone chips are not placed on the area devoid of arches. The wound is sutured layer by layer. Antibiotics are administered. An aseptic bandage is applied.

The wire used for the suture should be made of sufficiently elastic grades of stainless steel. As already noted, bone grafts are taken either from the tibia or from the crest of the iliac wing. Preference should be given to autografts, but cold-preserved homografts can also be used. The intervention is accompanied by intravenous blood transfusion. Blood loss should be promptly and fully replenished and adequate breathing should be maintained.

Premature extubation of the patient is dangerous. Only when there is complete confidence in the restoration of spontaneous breathing can the tube be removed from the trachea. The following should be ready for immediate use in the postoperative ward: a set of intubation tubes, an artificial respiration apparatus, a set of tracheostomy instruments, and a system for intra-arterial blood influence.

After the operation, the victim is placed in bed with a wooden board. A soft elastic cushion is placed under the neck area so that the victim's head maintains the specified position. The cable from the cranial vault traction bracket is thrown over a block secured to the head end of the bed. A 4-6 kg load is suspended.

Symptomatic drug treatment of the axis tooth fracture and displacement in the atlantoaxial joint area is used. Antibiotics are administered. According to indications - a course of dehydration therapy. On the 6th-8th day, the stitches are removed, the traction bracket is removed. A craniothoracic bandage is applied for 4-6 months, then it is removed. Based on the X-ray examination, a decision is made on the need to continue external immobilization. The issue of work capacity is decided depending on the nature of the consequences of the previous injury and the profession of the victim.

Occipitocervical arthrodesis according to I. M. Irger. The main difference of the method of occipitocervical arthrodesis according to I. M. Irger is in the technique of applying the weeding suture. Based on the calculations given, the author of the method considers this method to be more reliable and stable. The essence of the method is as follows.

The victim is placed on his side, general anesthesia is administered. A midline incision is used to dissect the tissues and skeletonize the area of the squama of the occipital bone, the posterior arch of the atlas, the spinous processes and arches of the second and third cervical vertebrae. In case of anterior subluxations of the atlas, the author recommends resecting the posterior arch of the atlas. The area of the posterior edge of the foramen magnum is skeletonized especially carefully, for which the atlanto-occipital membrane is dissected. Using a drill, two through holes are drilled, located 1.5 cm from the midline and above the posterior edge of the foramen magnum. A wire suture is inserted through these holes, running from front to back along the anterior surface of the squama of the occipital bone. The ends of the inserted suture are passed through the opening in the spinous process of the second or third cervical vertebra and tied securely. The placement and fixation of bone grafts is carried out in the same way as described by us. I. M. Irger emphasizes the difficulties of conducting a wire suture.