Cyst of bone

The bone cyst is a cavity in the solid form of connective tissue, most often developing in childhood, without obvious clinical signs until a pathological fracture due to bone tissue destruction.

The cyst bone refers to a large group of osteodystrophic pathologies of the bone system of the body. More than 70 years ago, many doctors linked the bone cyst with osteoblastoklastomy, then the cyst became an independent nosological unit and today belongs to tumor-like bone diseases. This group includes such osteodystrophic pathologies: 

• Chondromatosis.
• Cysta ossea solitaria (osteocystoma) - a solitary cyst of the bone.
• Cysta ossea aneurysmatica - aneurysmal cyst of bone.
• Intraosseous ganglion (juxtacortical cyst).
• Eosinophilic granuloma of the bone.

In the international classification of diseases of ICD, 10 cysts of the bone are in class M 85 - "Other disorders of bone density and structure", and is designated thus: 

• M85.4 - single (solitary) cyst of bone.
• M85.5 - aneurysmal cyst of bone.
• M85.6 - other cysts of bones.

[1], [2], [3], [4]

Epidemiology

Statistics on the bone cyst are as follows: 

• Among all benign neoplasms of the cyst, bones are diagnosed in 55-60% of cases.
• CCM - a solitary cyst is diagnosed in 75-80% of patients.
• ACC - an aneurysmal cyst is defined in 20-25% of cases.
• 70-75% of bone cysts are accompanied by pathological fractures.
• Simple solitary cysts most often affects males - 60-65%.
• Aneurysmal cysts are more often diagnosed in girls - 63%.
• Age of patients from 2 to 16 years. Bone cysts are rarely diagnosed in adult patients.
• Simple solitary cysts in 85% develop in tubular bones.
• Localization of solitary cysts in humerus bones - 60%.
• Localization of the solitary neoplasm in the femurs is 25%.
• Localization of aneurysmal cysts in tubular bones - 35-37%.
• Localization of aneurysmal cysts in vertebrae - 35%.
• The formation of aneurysmal neoplasms in the pelvic bones is 25%.
• Bone cysts in 65-70% of cases are formed in the bones of the upper limbs.

[5], [6], [7], [8], [9], [10], [11], [12], [13],

Causes of the cysts

Both types of cystic lesions in bone tissue in ICD-10 are defined as tumor-like pathology of the bone, unspecified etiology.

The causes of bone cysts have been studied for a long time, the information on clinical observations of similar diseases dating from the 17th century has been preserved. In the nineteenth century, Rudolf Vikhrov described the cyst bone as a decaying endochondrum for the first time, later in 1942 the cysts of the bones were divided into species - a juvenile simple cyst and an aneurysm cyst. Terminologically, the cystic bone formation is defined in the classification, but is a constant topic for medical discussions. One group of doctors believes that the cyst is a purely roentgenologic concept, rather a symptom than a separate pathology. In their opinion, cystic education is a consequence of systemic dystrophic lesion of bone tissue. Other theories also have the right to exist, although similarly to the first one they are not based on reliable clinical, statistical data. For example, one of the versions concerning the aetiology of the cyst examines the formation of a benign tumor as a result of the transformation of giant cell tumors. There is also a theory about traumatic etiology, which explains the appearance of a cyst due to a solid damage to bone tissue. Currently, the conventional theory is the theory of dystrophic changes in bone caused by a violation of hemodynamics. In turn, blood circulation can be disrupted both by trauma and by the general inflammatory process of the body. Recent observations of domestic surgeons and orthopedists allow us to talk about local dysfunction of intraosseous hemodynamics, activation of fermentation, destruction of glucanaminoglycans, collagen fibers and protein structures. As a result of this pathological chain, the osmotic and hydrostatic pressure in the cyst cavity increases, the bone tissue is destroyed, which does not withstand the dynamic load. Thus, in the bone growth zone the process of dysplasia is disrupted, ossification changes, pathological hypervascularization of the metaphyseal part and bone tissues is formed, a cyst is formed.

Such great disagreements lead to the fact that unclear, unspecified causes of the cyst of the bone do not allow to objectively classify the types, types, activity of tumors, respectively, the possibility of drawing up a single algorithm for treating such pathologies is excluded.

Summarizing, we can distinguish several most reliable options that explain the etiology of bone cyst development: 

1. Systemic dystrophic process, caused by the violation of blood supply to the bone tissue, resulting in the absorption of bone tissue (resorption) prevails over the process of osteogenesis (bone formation).
2. Violation of a certain stage in embryonic development, when there is an abnormality of laying the cells of the metaphysis of bone tissue. Metaphysis is the structural part of bone tissue, due to which the bone is able to grow in childhood and adolescence.
3. Chronic traumatization of bone.

[14], [15]

Symptoms of the cysts

Clinical manifestations, a symptomatic complex of tumors of bone tissue, consists of three main signs: 

• The presence or absence of severe pain.
• The actual tumor, which can be palpated, first determine its density and the expected size.
• The presence or absence of violations of the functions of the extremities and motor activity in general.

Symptoms of a cyst of a bone depend on the type of tumor, the rate of its development, localization and the ability to spread to surrounding tissues, structures.

Both simple solitary bone cyst (CCK) and aneurysmal have common etiopathogenetic causes, however their symptoms are different in the same way as radiographic visual indices. Common symptoms of bone cysts are related to such manifestations and symptoms: 

• The cyst will debut with clinical manifestations on the background of the child's general health.
• The bony cyst begins to show up with painful sensations in the fall, sudden movements.
• The cyst can provoke a pathological fracture in the area in which pain is periodically felt.

[16], [17]

Cyst in foot bones

The bony cyst of the lower extremity is most often diagnosed in children aged 9 to 14 years and is defined as fibrous osteitis of the hip or tibia. In 50% of cases, the first clinical symptom that can not be overlooked is a pathological fracture. Radiographically, the cyst in the leg bone is confirmed in the form of a picture showing a characteristic expansion of the bone tissue with a distinctly visible resorption zone in the middle. The pathological focus has clear boundaries, especially if there is no reaction from the periosteal (periosteal). The bony cyst of the leg refers to benign tumorous neoplasms and a favorable outcome in 99% of cases. The destruction of bone tissue develops spontaneously, the process begins with transient pain and minor swelling in the developmental region of the cyst.

Symptoms of leg cysts can be as follows:

• Transient pain in the cyst area for a long time.
• Violation of the supporting function of the leg, pain when walking.
• It is possible to rotate the leg outward with a pathological fracture.
• In the area of fracture, edema is always observed.
• With a fracture, the axial load on the leg provokes severe pain.
• Palpation of the fracture zone causes painful sensations.
• The symptom of the "stitched heel" is missing.

In clinical orthopedic practice, cases of spontaneous bone repair are not uncommon for 2-3 years. However, if the cyst is accompanied by a pathological fracture, a cystic cavity remains at the site of bone fusion, which is prone to recurrent development. Nevertheless, surgeons note a paradoxical phenomenon: a fracture can accelerate the fibrous restoration of bone tissue, as it helps to reduce the size of the cyst cavity. Often it is a pathological fracture that is a kind of therapy for cystic education proper, and trauma is treated as standard, like all other types of fractures. With this development, the cysts of the leg bone require dynamic observation, in which the main method of examination is X-ray. With a favorable course of the restoration process, the pictures show a slow but steady obliteration of the cyst cavity. In more complex cases, when bone destruction progresses, the cyst is scraped. Further, symptomatic treatment is prescribed, including with the help of injection steroids. Timely treatment of the cyst of bone tissue of the lower extremity allows avoiding recurrent fractures and pathological shortening of the leg as a result of deformation of bone tissue.

[18], [19]

Cyst of the talus

Astragalus seu talus, talus bone is part of the ankle joint structure, which also includes the tibia. The cyst of the talus is most often diagnosed in young people, less often in children under 14 years old, which distinguishes this pathology from many other cysts of bone tissue. It is well known that CCM and ACC are typical diseases associated with dysplasia of the bone growth zone, which develops in childhood. However, the specificity of the talus bone lies in the fact that it is almost completely responsible for the process of walking and assumes the entire weight of a person in motion. Thus, this bone, often undergoing a load, becomes a rather vulnerable zone, especially in the presence of osteopathology or calcium deficiency in the bone.

The talus bone transfers the load to the heel, the middle zone of the foot, so often its pathologies manifest themselves in the bones of these zones.

Clinical signs of talus cyst: 

• The onset of cyst development is hidden.
• The active cyst of the talus manifests itself in the form of aggravated pains that become intense during prolonged walking or running.
• The cyst of the talus can provoke a fracture of the ankle.

As a rule, such a tumor is defined as benign, but it must be removed as early as possible in order to prevent pathological fractures.

The cyst is visualized as a subchondral neoplasm with clear contours. The tumor does not extend to the joint, but can limit its mobility.

The localization of the cyst in the talus is considered not very favorable due to frequent recurrences of the pathology, even with a carefully performed operation. A high risk of complications is associated with a specific anatomical structure of the talus and its intensive blood supply. Disturbance of blood flow, both at the time of a pathological fracture, and during an unavoidable operation in adult patients, can lead to avascular necrosis and even to disability of the patient. In addition, the talus bone is surrounded by other bone tissues - heel, scaphoid, bone of the ankle, so determining the exact location of the cyst or fracture, and rapid access is very difficult. Operation pop about cyst astragalus seu talus is considered one of the most difficult among all operational techniques for the removal of bone cysts, the process of graft survival is also complex. Time recovery, rehabilitation after surgery on the talus can last for 2-3 years. In 5-10% of cases, treatment results in disability of the patient, mainly this refers to patients older than 45 years.

[20], [21], [22],

Cyst of metatarsal bone

Metatarsus, metatarsal bone, is a combination of five small tubular bones, rather short and brittle compared to other bones of the foot. Each of the five parts of the metatarsal bone in turn consists of the base, body and head, the most prominent forward, the long one - this is the second metatarsal bone, the shortest and strongest - the first. It is in them that the bone cyst is most often formed, although according to statistics such tumor formations in these parts of the foot are rarely diagnosed early and, rather, they are confused with other bone diseases. The structure of the metatarsal bones is very similar to the metacarpal, but still visually look narrower and squeezed laterally, although for all their fragility they successfully amortize our gait, they help withstand static body weight loads.

Diagnosis of the metatarsal cyst is very difficult due to various reasons: 

• Rare cases of the disease and the absence of statistically, clinically confirmed information about such pathologies.
• Similarity of symptoms of cyst metatarsus and other tumor-like formations in this zone.
• Frequent pathological fractures of the metatarsal bone in the presence of osteopathy.
• Absence of unified diagnostic differential criteria.

Errors in the examination and diagnosis of the CCM or ACC of the metatarsal zone are quite common and are one of the reasons for the high incidence of disability in patients. In addition, there are descriptions of the malignancy of the metatarsus bone cyst, when a neglected process or recurrence of a spontaneous fracture leads to malignancy of the tumor. Diagnosis should be thorough and include in addition to collecting anamnesis and a standard X-ray examination, even CT, ultrasound, scintigraphy, histology. Conservative treatment of cysts of metatarsals does not bring any result, therefore it is most often operated on. The only way to avoid surgery can be an uncomplicated fracture, after which the cyst collapses and disappears. But such cases can be only in a few patients, mainly in the age of 12 years. Treatment of adult patients is much more complicated and traumatic. The cyst is resected, the bone defect is filled with aaloplastic material.

[23], [24]

Cyst on the bones of the hand

Manus - the upper limb, the hand consists of such anatomical parts: 

1. Angulum membri superioris is a shoulder girdle, which in turn consists of such structural parts: 
   • Shoulder.
   • Collarbone.
   • Articulatio acromioclavicularis - acromioclavicular joint.
   • Humerus - humerus.
2. Forearm: 
   • Ulna - a pair of ulnar bone.
   • Radius is the twin radius.
3. Brush: 
   • The wrist, consisting of 8 bones.
   • Scaphoid, trihedral, semilunar, pea-bones - proximal level.
   • Trapezoidal, capitate, hook-shaped bones - distal level of the hand.
4. Pasty, consisting of 5 bones.
5. The fingers are the bones of the phalanx.

The cyst of the arm bones is predominantly localized in the humerus, much less often cystic dysplasia is noted in the forearm or in the bones of the hand. This is due to the fact that the CCM and ACC prefer to form in the metaphyseal sections of the tubular long bones, small and short bone structures simply do not have the necessary width of the cavity for the development of tumors and are not able to intensively and rapidly elongate during the period of intensive growth of a person - childhood and adolescence. Clinical cases of diagnosis of solitary cysts in the distal phalanges of the fingers of adult patients, described in the medical literature can be considered a rarity and most likely, such definitions are erroneous. Quite often, bone cysts are difficult to separate from similar osteoblastoclast or similar chondrames. Precise diagnosis and differentiation is possible only with CT or MRI, which is not always available to patients.

Radiographically, the bony cyst looks like a light area of rounded shape in the bone metaphysis, the tumor has clear boundaries, inclusions are usually absent, the cortical layer is significantly reduced, often swollen. Histological analysis of the wall of the formation shows a weakly vascularized connective tissue with signs of hemorrhage with an aneurysm cyst or without them in the determination of a solitary cyst.

The process of development of the cyst in the arm bones is always accompanied by focal destruction, bone resorption. Gradually increasing, the cyst is shifted toward the diaphysis without touching the shoulder joint, without causing a change in the periosteum and any signs of inflammation in general.

The symptomatology of cystic education in the upper limb is nonspecific, the patient can feel periodic discomfort with rotational movements of the hand, lifting his arm up while doing sports. The tumor is rarely manifested by visual signs, only a large cyst may look like an obvious swelling.

The most typical symptom, more accurately evidence of the neglect of the process, is a pathological fracture. Most often, the fracture is localized in the forearm, it can be triggered both by physical activity (lifting of gravity), and falling, bruise. A pathological fracture or fracture of the bone quickly fuses, with this the cyst cavity decreases, it disappears.

Diagnosis of the cyst on the bones of the hand using X-rays, osteoscintigraphy, computed tomography and ultrasound. Treatment with timely diagnosis and a small amount of cyst is done conservatively, by immobilizing the upper limb and puncturing. In the absence of positive dynamics for 1.5-2 months, the cyst is surgically removed. Also, the operation is indicated if, after a pathological fracture, the cyst does not decrease. It must be removed in order to avoid a recurrent fracture of the arm.

The prognosis of cysts in the arm bones of children is generally favorable, the specificity of the child's organism is that the abilities for self-correction and reparation at this age are very high. In adults, the process of recovery, rehabilitation of the hand lasts much longer, damage to the muscle tissue during surgery can provoke some limitations in the functions of the upper limb. In addition, there is a risk of rejection of the bone implant inserted into the resection defect. To fully implant the alloplastic material or autograft, it takes from 1.5 to 3 years.

[25], [26], [27]

Solitary cyst of bone

In the last century, a solitary simple cyst was considered the final stage in the formation of a giant-cell bone tumor. Currently, the solitary cyst of the bone according to ICD-10 is considered an independent nosological unit. The disease most often affects children and adolescents, it is not accidental that it is also called a juvenile bone cyst.

Cysta ossea solitaria or a solitary cyst of the bone is diagnosed more often than an aneurysmal tumor. In 65-70% of the solitary cyst is detected in childhood in boys and looks like a benign single-chambered formation localized mainly in the humeral girdle or in the hip bones. The symptoms of a simple bone cyst are non-specific, often the manifestation of a clinical sign and the reason for going to the doctor becomes a pathological fracture. Statistically, among patients with solitary bone cyst (CCM), boys aged 9 to 15 years predominate. In adult patients, a solitary cyst is not found, thus, the established diagnosis of CCM in individuals over the age of 40 can be considered an error due to insufficient differentiation of benign bone tumors.

Localization and symptomatology of a solitary cyst bone: 

• The predominant zone of CCM development are tubular long bones - the zone of the shoulder girdle, femurs. Localization of a simple cyst in small short bones is not typical and requires careful differentiation from the chondroma, sarcoma, ganglion.
• The CCM is asymptomatic for a long period, sometimes up to 10 years.
• Indirect signs of the development of a solitary cyst may be transient pain in the area of the tumor.
• In the developmental area of the cyst, if it increases to 3-5 centimeters or more, a slight visible swelling is possible.
• A characteristic feature of the large cyst formed is a pathological spontaneous fracture, uncomplicated by displacement.
• At a primary examination and palpation, the cyst is felt as a painless seal.
• Pressing on the wall of the tumor causes the deflection of the destroyed bone segment.
• The volume of movement of the cyst is not limited, except for the femur cyst that provokes intermittent claudication.

. The solitary bone cyst develops within the clinical stages: 

• Active development of the cyst causes a thickening of the bone visible on the X-ray, can provoke a pathological fracture, immobilization of the damaged joint. The active stage lasts from six months to one year.
• Passive stage of development of the cyst begins with the moment of displacement of the tumor in the center of the bone, while the cyst significantly decreases in size, falls off. This stage can also be asymptomatic and last from 6 to 8 months.
• The stage of bone restoration starts from the moment of the termination of the growth of the bone system, after 1.5-2 years from the beginning of the active stage. Nevertheless, destructive bone lesions remain and can still be a provoking factor of a pathological fracture. Fracture in turn helps to close the cavity of the cyst and compensatory replacement mechanism of filling the cavity with bone tissue.

The juvenile solitary cyst of the bone is most often treated with a conservative method and immobilization of the affected area. If this method does not yield results and the disease progresses, the cyst is surgically removed, resection is performed within intact tissues with obligatory allo or autoplasty.

Treatment of patients older than 16-18 years is 90% surgical, since the detection of a cyst at this age indicates its long development and significant bone destruction, which is a huge risk of multiple recurrent fractures.

Aneurysmal cyst of bone

ACC or an aneurysmal cyst of bone in surgical practice is rare, but the complexity of its treatment is not due to individual diagnoses, but rather to the end of the unspecified etiology. In addition, ACC is most often detected in the spine, which in itself indicates the severity of the disease and the risk of complications from the spinal cord. Aneurysmal cyst of a large size or a multi-chamber tumor localized in the bone tissue of the vertebra, can cause paresis and paralysis, and also tends to malignant.

AAC is a significant, extensive lesion of bone tissue, the cyst looks like a multi-chamber, less often a single chamber cavity filled with blood exudate, the walls may be with small parts of the bone. Until the middle of the last century an aneurysmal tumor was not isolated as an independent disease and was considered a variety of osteoblastoklastomy. Today ACC is diagnosed as a benign tumor, burdened with multiple complications when localized in the spine.

The specificity of an aneurysmal cyst development is that it is very aggressive, unlike a solitary tumor. Rapid growth and increase in its size sometimes resembles a malignant process, but AAC very rarely maligns and is successfully successfully operated with timely detection. Most often AAC is diagnosed in children during intensive growth - 6 to 15-16 years, according to some information aneurysmal tumors predominate in girls, although this information is contradictory and not confirmed by reliable statistics. The favorite location of the AAK is the cervical and thoracic spine, sometimes it forms in the bones of the hip joint, in the lumbar region and extremely rarely in the calcaneus. AAC of large sizes can capture several vertebrae at once - up to 5, which is complicated by paralysis, including irreversible ones.

Symptoms of AAC - aneurysmal bone tumor: 

• The onset can occur without clinical signs, asymptomatic.
• As the child's cysts increase, the aching aching pain in the area of bone damage is disturbed.
• The pain is aggravated by physical exertion, stress, can disturb at night.
• In the zone of cyst formation, the swelling is clearly visible.
• The cyst, located near the joint, limits the volume of its movements.
• Aneurysmal tumor in the femur causes lameness, disrupts the supporting function.
• A large cyst provokes paresis and partial paralysis, which debuts at first sight for no apparent objective reason.
• To provoke the acceleration of the development of a cyst may be injuries or bruises.

AAC can have such forms of development: 

• Central AAK - localization at the center of the bone.
• Eccentric AAC - an enlarging cyst captures nearby tissues.

Uncomplicated aneurysmal bone tumor can be closed independently after a pathological fracture, however such cases are very rare, most often AAC has to operate. The most difficult are operations to remove the cyst on the vertebra, since the surgeon works with a very vulnerable and dangerous zone - the vertebral column and multiple nerve endings. After removal of AAC, a very long recovery period, rehabilitation measures are required, in addition aneurysmal cysts are prone to recurrence even in the case of a carefully performed operation. The risk of recurrence is very high, according to statistics, 50-55% of patients who have been through surgical treatment again get to the surgeon. The only way to reduce the risk of recurrence can be permanent medical supervision and a regular examination of the bone system.

[28], [29], [30], [31], [32]

Forms

Symptoms of a cyst of a bone depending on its kind: 

1. A solitary, youthful bone cyst is most often diagnosed in boys - in 60-65% of cases. In adult patients, SSC is extremely rare and can be considered a neglected dystrophic process, not diagnosed for a long period. The most typical solitary cyst appears at the age of 9 to 16 years, when the child begins the process of intensive growth. The preferred location of SSC localization are long tubular bones, usually a metaphysis of the thigh or humerus. The onset of the pathology proceeds latently, asymptomatically, occasionally the child can make complaints about periodic pains in the bone or swelling in the development zone of the cyst. In 60-70% of cases, the first obvious sign of SSC is a pathological fracture, provoked by mild trauma - a minor bruise or a simple drop. When the tubular bone is affected by a cystic neoplasm, it thickens and has a peculiar clavate shape in the developmental region of the cyst. Palpation of the bone does not cause painful sensations, the pressure on the cyst wall shows some deflection in the softening zone of the bone tissue. The joint, the limb do not lose their mobility, their functions, the only problem for the motor activity of the thigh bone or ankle bone may be the loss of a proper sense of support. The development of a simple bone cyst proceeds according to certain stages: 
   1. The active stage of development, which lasts about a year and is characterized by a bloating, rarefy metaphysis, which corresponds to an x-ray picture showing an obvious process of osteolysis - complete destruction of the bone without compensatory replacement by other tissues. At the same time, there is a distinct restriction of the mobility of the nearby joint, contracture, there may be recurrent pathological bone fractures. 
   2. The active phase gradually turns into a latent, passive stage. Especially it is characteristic for the development of the cyst, not accompanied by fractures and painful sensations. The cyst can capture the meta-diaphysis, gradually shifting further away from the growth zone, decreasing in size. The solid cyst in the passive stage is always asymptomatic and can be latent for up to six months. 
   3. The stage of restoration of bone tissue. The latent solitary cyst slowly moves to the diaphysis, this occurs within a year and a half or two years. All this time, bone tissue is destroyed, but it does not manifest itself clinically, except there can be a sudden change in the background of complete health and the absence of a traumatic factor - a fall or a bruise. Fractures are also not felt as strong, traumatic and, depending on localization, can be carried by the child in the literal sense of the word - on the legs. Growing up, the fracture sites help narrow the cavity of the cyst, reducing its size. In clinical orthopedic practice, this phenomenon is called restoration on site. In the area of the bony cyst, there may be a seal or a very small cavity. Nevertheless, the process of bone repair is completed, in general from the debut of the development of a solitary cyst to its decrease takes about 2 years. 
2. Aneurysmal cyst is most often diagnosed in girls, neoplasm develops in bone tissue of different structure and localization - in tubular bones, in the spine, in pelvic or femoral bones, extremely rarely - in the calcaneus. In girls, the aneurysmal cyst is clinically manifested in the pubertal period, before the first menstrual cycle, until the hormonal system is completely stabilized. At this time, not only the hormonal background changes, but also the blood coagulation system, which largely affects the blood supply of bone tissue. At the age of 11 to 15 years, the ACC of the femur is most often diagnosed. For the aneurysmal cyst, unlike the solitary one, there is a very acute, clinically manifested beginning, the symptoms of which can be as follows: 

• Painful sensations, paroxysmal, localized at the site of development of the cyst.
• Visible puffiness, swelling of the bone.
• Seal, which is clearly palpable.
• Local hyperthermia, reddening of the skin in the area of the cyst.
• Expansion of the venous vessels in the place where the ACC develops.
• With pathological vertebrae fractures in the acute stage, paresis or partial paralysis is possible.
• After an acute stage, the symptoms of a bone cyst subsided, the process is stabilized, but tissue destruction continues.
• X-ray stabilization of the acute period looks like a significant resorption of bone tissue, in the center of the focus is a capsule, which includes clots of fibrinous tissues, remnants of the hemorrhage process.
• ACC in the pelvic bones can reach huge sizes - up to 20 centimeters in diameter.
• During the stabilization period (6-8 weeks), calcification of the bone tissue is possible, so this form of cyst is called ossifying the subperiosteal aneurysm cyst.
• With an aneurysmal cyst that develops in the spine, a visible extensive compaction, a swelling of the bone, is possible. In addition, the child is formed compensatory muscle tension, which aggravates the pain symptom.
• For the defeat of the spine is characterized by a specific compensatory posture - the support of the hands on the hips, pelvic bones, often the children in a sitting position try to support the head with their hands. All this indicates a violation of the normal supporting function of the spinal column.

In general, ACC symptoms develop within the clinically defined phases: 

• I - resorption and osteolysis.
• II - limitation of mobility.
• III - recovery phase.

The period of development of the aneurysmal cyst of the bone from the debut of the disease to the last phase can last from one to three years. Also, ACC is characterized by relapses, according to surgeon-pathologists they reach 30-50% of all cases detected.

[33], [34], [35], [36], [37], [38], [39]

Diagnostics of the cysts

Diagnosis of bone cysts is always complex, this is due to the absence of specific symptoms, and a similar radiographic picture of other neoplasms, and not fully refined etiology of intraosseous benign tumors. In the process of determining the type and nature of the cyst flow, mistakes are often made, their percentage is very high - up to 70% of erroneous diagnoses. Inaccurate diagnosis of the cyst bone leads to incorrect treatment tactics and frequent relapses, less often increases the risk of malignancy of the tumor.

[40], [41], [42], [43], [44]

Differential diagnosis

The main fundamental criteria for the precise differentiation of benign tumors in the bone are the clinical and radiological parameters, the indices: 

• Anamnesis, medical history.
• Age of the patient. In most cases, the development of a solitary or aneurysmal cyst is characteristic of childhood and adolescence.
• Localization of the bony cyst not only in the anatomical structure of the body, but also in the structure of bone tissue.
• The size of focal lesion.
• Presence or absence of pathological fracture.
• Histological indices.

It is very important to differentiate the bone cyst from malignant intraosseous tumors, which requires urgent and specific treatment. Such diseases can be osteogenic or osteoclastic sarcoma, osteoblastoklastoma, carcinoma

Difference aneurysmal cyst from malignant tumors can be its preferred location in tubular, large bones and location in the metaphysis, diaphysis. A solitary tumor, unlike malignant neoplasms, never causes a reaction from the periosteum and does not spread to nearby tissues.

Differential criteria that help distinguish a malignant process from a CCM or ACC

Disease	Osteoblastoclastoma	ACC or CCM
Age	20-35 years and over	2-3 years -14-16 years
Localization	Epiphysis, metaphysis	Metaphysis, diaphysis
Bone form	Explicit swelling of the bone	Spindle-shaped form
Contours of the source of destruction	Clear boundaries	Clear
Cortical layer condition	Intermittent, thin, wavy	Smooth, thin
Sclerosis	Not visible	No
Periodic reaction	Absent	Absent
Condition of the epiphysis	Thin, wavy	Without any obvious changes
Adjacent diaphysis	Without changes	Without changes

Methods that can include diagnosing a cyst bone: 

• Anamnesis collection - complaints, subjective and objective symptoms, the presence of pain, its irradiation, the time and duration of the symptoms, their dependence on the load and the possibility of cupping with medicines.
• Clinical examination.
• Definition of orthopedic status - posture in motion, at rest, functional activity, limb asymmetry, muscle symmetry, presence or absence of contracture, revealing changes in the vascular pattern.
• Radiography.
• Contrast cystography.
• CT scan.
• Ultrasound.
• MRI - magnetic resonance imaging.
• Computer thermography - KTT.
• Puncture.
• Determination of intraosseous pressure - cystobarometry.

Kistu bones differentiate with such diseases: 

• Osteosarcoma.
• Giant cell tumor.
• Non-classified fibroids.
• Osteoma.
• Primary osteomyelitis.
• Osteoblastoma.
• Chondroma.
• Lipoma.
• Chondroblastoma.
• Fibrous dysplasia.

Topical diagnosis is also indicated before surgery for the removal of the CCM or ACC, in addition the patient needs dynamic observation, therefore, in periodic diagnostic monitoring of the condition of the cyst and bone tissue as a whole.

Treatment of the cysts

Despite the availability of high-tech equipment, new methods of treatment, the cyst of the bone is still considered a difficult-to-supervise disease prone to recurrence.

Bone cyst diagnosed in childhood and not having complications is treated with conservative methods. Operations are shown only for children older than 3 years, in cases of aggressive development of the process. If the tumor provoked a spontaneous fracture, the treatment of the cyst bone is in the standard steps that orthopedists and surgeons take in the treatment of conventional traumatic fractures. At the slightest suspicion of a bone fracture, an immobilizing material is placed on the bone, then the diagnostic measures are carried out. The cyst and fracture in the hip and shoulder area require a cast bandage and immobilization for 1-1.5 months. If the cyst is identified, but there is no fracture, the patient is shown maximum peace and relief - a bandage bandage on the shoulder or assisting the stick, crutches when walking. Conservative treatment includes punctures, which can significantly speed up the process of bone tissue repair. Treatment of the cyst bone with the help of drug puncture is as follows: 

• Intraosseous anesthesia is performed.
• The cyst is punctured, the material for histological examination is taken from it.
• The dysfunctional cavity of the cyst is washed with an aseptic solution.
• A protease inhibitor is introduced into the cavity to neutralize the aggressive fermentation (countercrack). Children over 12 years of age are shown to enter the cavity of the Kenalog or hydrocortisone.
• The end of puncturing is the perforation of the cyst from all sides to create an outflow of exudate and reduce intracavitary pressure.
• Puncture is performed several times at the time determined by the surgeon (2-4 weeks).
• After the end of treatment, the control of the bone tissue state is required with the help of radiography (2-3 months after the last puncture).
• During the puncturing the affected area of the cyst is immobilized.
• After successful puncture and closure of the cavity cysts prescribe a complex of exercise therapy, the course of at least 6 months.

The total duration, which involves the conservative treatment of the cyst bone, is at least six months. If conservative treatment is ineffective, as evidenced by a dynamic observation for 2-3 months, the cyst is surgically removed by resection and subsequent bone resection with auto or alloplastic material.

Alternative cure for bone cysts

It is obviously inexpedient to talk about alternative means of treating the bony cyst. Any new growth that develops in the body is considered tumor-like, that is, prone to complications and a more serious process-malignancy. The bony cyst is considered to be a poorly understood pathology, the etiology of which has not been determined to date, so alternative cyst bone treatments not only do not help, but can also do harm.

Ineffective treatment of bone cysts by so-called alternative methods is due to pathogenetic features of tumor formation. At the heart of pathogenesis is a local impairment of blood supply to bone tissue. Such intraosseous "starvation" leads to activation of the enzymatic function, lysis, which results in the destruction of glycosaminoglycans, protein elements and collagen structures. This complex process is always accompanied by increased osmotic and hydrostatic pressure in the cyst cavity, other chronic destructive processes inside the bone. That is why, alternative means for treatment of ACC or CCM are not able to bring the desired benefits, too high a barrier for active plant substances that does not allow achieving the goal.

In addition, all patients who want to experiment with their health should pay attention to the keyword "swelling" in determining the diagnosis, as the bony cyst is a benign tumor-like formation. Especially dangerous is the treatment of unverified cyst vertebrae, because all neoplasms in the spine are prone to malignancy and inadequate therapy can lead to irreversible consequences.

The only remedy that is relatively safe and able to alleviate the symptoms of a pathological fracture provoked by a cyst may be a special diet. In the diet patient should include products,

Rich in vitamins, calcium. It is very useful to eat fruits, vegetables, rich in vitamin C, also the presence of vitamin D and phosphorus is important.

Products that help to quickly restore bone tissue: 

• Milk and sour-milk products.
• Fish, including the sea.
• Sesame seeds.
• Citrus.
• Sweet Bulgarian pepper.
• Currant.
• Cherry.
• Hard grades of cheese.
• Jelly, marmalade, any products containing gelling agents.

From the menu it is necessary to exclude carbonated drinks, limit the use of sweets, coffee.

In other respects, treatment of the bony cyst should be done under the strict supervision of the doctor, and not with the help of questionable and unverified recommendations, since only adequate therapy can restore motor activity and restore normal functions of the bone system.

[45], [46], [47], [48], [49]

Prevention

To date, unified recommendations for the prevention of solitary or aneurysmal bone cysts. Prophylaxis of a cyst of a bone in patients of children's and older age can consist only in observance of such simple rules: 

• Regular check-ups, starting from the moment of the birth of the child. Consultation of the surgeon should become an obligatory annual procedure, in the presence of anxiety symptoms - complaints of pain, gait, movement, posture, surgeon's help, orthopedist need immediately. The earlier the bony cyst is identified, the more successful the treatment will be and most likely the operation will not be required.
• Exclude recurrence of the cyst in the bone tissue can only be through surgery and subsequent long-term treatment, which should not be interrupted even with apparent recovery.
• Children who have a history of bone disease, musculoskeletal system, systemic diseases, prolonged chronic inflammatory processes should be protected from any traumatic, mechanical factor.
• Children and adults engaged in active sports should undergo medical examinations, including an X-ray of the bone system more often than those who lead a passive lifestyle. Professional injuries, bruises can become a factor that causes the development of an aneurysmal cyst bone.
• The parent must be attentive to any changes in the child's state of health. Most often the onset of the development of CCM and ACC is asymptomatic, only occasionally disturbing a small patient with transient pain. In addition, pathological fractures do not always manifest in the clinical sense as standard fractures, the only sign of them can be a small limp, a limitation of the volume of arm movements, compensatory postures that help reduce the burden on the spine.

Prevention of the cyst bone in the absence of a single standard rules, obviously, should become the business of the person himself, or, in the case of the child, his parents.

[50], [51], [52]

Forecast

Obviously, only the attending physician can talk about what can be predicted cysts of a bone. Everything depends on the patient's age, duration of the latent period of cyst development, presence or absence of complications, pathological fracture.

In general, the prognosis of the cyst bone looks like this: 

• Children up to 15-16 years - the forecast is favorable in 85-90% of cases. Relapses occur with an aneurysmal cyst or technical errors committed during the operation. Repeated operations, although traumatic, are not considered severe. In addition, the children's body has a high degree of reparativity, so the recovery of motor activity is guaranteed in 99% of cases.
• Adult patients are more likely to tolerate bone cyst treatment, they are more likely to have relapses. In addition, the diagnosis of ACC in patients older than 35-40 years is difficult, the cyst has to differentiate from other tumorous diseases most often against a pathological fracture. The fracture is also more difficult to transfer, the recovery period is much longer than in children. Prognosis of cyst bone in adult patients in 65-70% of cases is favorable, the rest of the diseases refers to undifferentiated malignant or complex tumors, including intraosseous. Also, the probability of successful recovery reduces the wrong treatment strategy. Conservative therapy of bone cysts can be effective only in childhood, in other patients it can lead to massive bone destruction and serious complications. The most dangerous vertebra cysts in terms of compression symptoms and the general vulnerability of the spinal column.

The statistical data on the recurrence of the process are as follows: 

• CCM (solitary bone cyst) - relapses are noted in 10-15% of cases.
• ACC (aneurysmal bone cyst) in 45-50% is prone to recurrence.

In general, the prognosis of the bony cyst depends on a timely and differentiated diagnosis, which in turn determines the therapeutic tactics and strategy of the rehabilitation period.

The bone cyst is considered a benign formation, which can be attributed to the borderline between the present tumor and the osteodystrophic process of bone tissue dysplasia. The main danger is the long asymptomatic course of the disease, which often ends with a pathological fracture. The cyst of the bone, localized in the upper part of the body - in the upper limbs, shoulder girdle, in the vertebrae, unburdened fracture, usually does not require surgical treatment. The cyst of the bones of the lower limbs is extracted in order to prevent the potential risk of fractures or their relapses. Solitary cysts of the bone are prone to spontaneous resolution, aneurysmal neoplasms are more pathological, although in 90-95% with adequate and timely treatment their prognosis is also favorable, the only complication can be considered a fairly long recovery period, which requires patient patience and all medical recommendations.

[53], [54]