Osteoid Osteoma

Generality

The osteoid osteoma is a benign bone tumor that has the peculiarity of deriving from osteoblasts.

Due to causes still unknown, the osteoid osteoma affects, mainly, the long bones of the limbs (femur, humerus, tibia, etc.) and, although to a lesser extent than in the case just mentioned, the vertebrae of the vertebral column (in particular the cervical vertebrae and lumbar vertebrae).

Where it arises, the osteoid osteoma is responsible for symptoms and signs, such as: pain (main symptom), swelling, bone deformities, changes in bone growth and muscle atrophy; in the most serious cases, this symptomatology can be so severe as to seriously affect the quality of life of the patient.

In general, doctors reach the diagnosis of osteoid osteoma later: a thorough physical examination, a thorough medical history and a series of radiological examinations; sometimes, however, they also need to resort to blood tests and above all to a biopsy.

The osteoid osteoma heals spontaneously within a few years; nevertheless, it still needs treatment, as the pain it causes is very intense and debilitating (especially during the night).

What is the Osteoid Osteoma?

The osteoid osteoma is an example of a benign-type bone tumor, which has the peculiarity of originating from osteoblasts . The osteoid osteoma, therefore, can be defined with the expression of benign osteoblastic tumor (where the term "osteoblastic" expresses not only the binding to osteoblasts, but also the belonging of the tumor in question to the category of bone neoplasms).

Main features of osteoid osteoma

The osteoid osteoma can arise in any bone of the human skeleton; however, numerous medical studies have shown that this benign tumor:

In 80-90% of cases, it affects the long bones of the limbs, therefore skeletal elements such as the femur, the humerus, the tibia, etc.
In 7-10% of cases, it affects the vertebrae of the spine, with a particular preference for the lumbar vertebrae (59% of patients with a vertebral osteoid osteoma) and for the cervical vertebrae (27% of patients with a vertebral osteoid osteoma) .
In the remaining percentage, it is located on the phalanges of the fingers of the hand, on the astragal of the foot or inside "important" joints such as the knee, ankle or hip.

As regards size and appearance, the osteoid osteoma generally consists of a cell mass that is at most 1.5-2 centimeters large, very similar to a nodule, richly vascularized and yellowish or red in color.

The formation of an osteoid osteoma can involve, indifferently, only one bone or more adjacent bones.

Brief study on the sites of osteoid osteoma

At the femoral level, the osteoid osteoma appears to prefer the proximal epiphysis, in particular the area between the large and small trochanter of the femur; at the level of the tibia and the humerus, on the other hand, it appears to have a preference for the diaphysis, ie the central bone portion between the two epiphyses.

On the vertebrae, the sites in which it is easier to find an osteoid osteoma are: the spinous process, the so-called vertebral spongiosa and the peduncles; rarely, the osteoid osteoma involves the bodies of the vertebrae.

Epidemiology

The osteoid osteoma represents 10-12% of all benign-type bone tumors; said in other words, between 10 and 12 people every 100 with a benign bone tumor carries an osteoid osteoma.

Osteoid osteoma can affect people of any age; however, statistics show that he has a predilection for people aged between 4 and 25 years.

For reasons still unknown, between males and females, the osteoid osteoma has a predilection for the former (the ratio is 3 to 1 in favor of men).

Causes

Despite numerous studies conducted on the subject, the causes of osteoid osteoma are unknown.

Lately, then, some experts have questioned the tumor nature of the osteoid osteoma, advancing the hypothesis that the latter is the result of an inflammatory process.

Symptoms and Complications

Where the osteoid osteoma is located, the symptoms and signs resulting from it are:

Ache. It is the main symptom of osteoid osteoma as well as the most common;
Swelling. The nodular appearance of the osteoid osteoma causes a swollen area similar to a small protuberance to appear at the skin level;
Abnormal increase or reduction in bone growth (obviously, these are two symptoms that may affect younger patients, where bone development is not yet complete);
Bone deformity;
Difficulty moving the affected limb (when, of course, the osteoid osteoma locates at the level of a femur, a tibia, a humerus, etc.);
Muscular atrophy.

Characteristics of pain

The pain resulting from the presence of an osteoid osteoma is a dull- type painful sensation, which tends to remain mild during daylight hours, and become decidedly more intense during the night.

Generally, it is not related to physical activity (so it does not increase by moving), but it can still prevent it from proceeding smoothly and constantly.

At the beginning and for the first time following the onset, he is sensitive to the use of traditional painkillers (eg: NSAIDs); after which, the latter gradually become less and less effective.

In general, pain related to the presence of an osteoid osteoma tends to worsen over time.

Complications

In the long run, the pain produced by an osteoid osteoma can worsen to the point that, at night, it deeply disturbs the night rest, while, during the day, it makes it very difficult to carry out the most normal daily activities.

In individuals of young age, the osteoid osteoma can cause, more or less after its onset, more or less serious scoliosis problems.

CAN A MALIGNA TRANSFORMATION BE POSSIBLE?

The medical literature does not report cases of osteoid osteoma in which a malignant bone tumor originated from the latter. In other words, so far no cases of malignant transformation of an osteoid osteoma have been observed.

Diagnosis

In general, doctors reach the diagnosis of osteoid osteoma later: a thorough physical examination, a thorough medical history, a series of radiological investigations, a bone biopsy of the abnormal nodule and, finally, a blood test.

Physical examination and medical history

The physical examination and the anamnesis consist essentially in a careful and precise evaluation of the symptoms and signs presented by the patient, at the time of the first medical examination.

For individuals with a suspected osteoid osteoma, these two investigations usually include:

Questions related to pain. With regard to the painful sensation, the doctor may ask: when did he arise and how long has he been doing it; if it worsens during the night or remains stable; if it prevents the performance of the most common daily activities; etc.
Palpation of the painful and swollen area. The doctor palpates the painful and swollen area, to understand the consistency of the protuberance and whether the pain associated with the latter worsens or not.
Health related questions. The answers are useful in future projections, when planning a possible treatment.

Although accurate, the physical examination and the anamnesis do not allow to draw any definitive conclusion; for this we need the aforementioned radiological investigations and possibly the biopsy.

Radiological examinations

Observed through tests such as X-rays, CT scans, bone scintigraphy or nuclear magnetic resonance, the osteoid osteoma exhibits some features that distinguish it from most other benign and malignant bone tumors.

These characteristics explain the importance and the indispensability of the use of an accurate radiological investigation.

Curiosity

A bone tumor that, on radiological examination, appears very similar to the osteoid osteoma (thus complicating the diagnosis) is the so-called osteoblastoma ; exactly like the osteoid osteoma, osteoblastoma is a benign type of bone neoplasm that originates from osteoblasts.

Biopsy

Bone biopsy consists in the collection and subsequent analysis in the laboratory of a sample of cells belonging to the osteoid osteoma (or to the nodular mass that the doctor considers to be an osteoid osteoma).

The biopsy examination is a confirmatory investigation, which eliminates all doubts concerning previous diagnostic studies.

Blood analysis

During the diagnostic research related to an osteoid osteoma, blood tests are useful from a "differential diagnosis" perspective; indeed, they help to verify that the present symptomatology does not depend on a bone infection or a malignant bone tumor.

Therapy

Before discussing the treatment of osteoid osteoma, it is necessary to point out two concepts:

The osteoid osteoma is an alteration of the bone tissue with the tendency to disappear in a completely spontaneous way, within a few years.
During the time that the osteoid osteoma remains, pain depending on the latter may be (for reasons that are still unexplained) a bearable or absolutely intolerable sensation.

The treatment of osteoid osteoma depends on the intensity of the pain sensation present. In fact, when the pain is mild and as long as it is maintained, the therapy is conservative; while, when the pain is very intense and unbearable, the treatment adopted is surgical.

Conservative therapy

The conservative treatment of the osteoid osteoma consists, substantially, in the administration of the so-called NSAIDs, ie medicines known not only for their anti-inflammatory properties (the acronym NSAID stands for Non-Steroidal Anti-Inflammatory Drugs) but also for their pain-relieving properties.

NSAIDs are indicated in the presence of limited pain, as they tend to be effective only in this circumstance; this means that any worsening of the painful sensation could coincide with their total loss of efficacy.

When NSAIDs lose much of their effectiveness and the pain has reached an unbearable level of intensity, the patient is forced, if he wants to feel better, to undergo surgical treatment.

DURATION OF CONSERVATIVE CARE

In the absence of worsening of the pain sensation, the need to resort to NSAIDs is less when the osteoid osteoma disappears.

In other words, the conservative treatment of the osteoid osteoma lasts the time of permanence of the latter (if, obviously, the pain does not worsen).

Important note

NSAIDs are safe drugs; however, before prolonged use, it is good for the patient to consult their doctor to find out the appropriate dosage, contraindications and possible side effects.

Surgical therapy

The surgical treatment of the osteoid osteoma consists in the operation of removal of the nodular mass representing the tumor in question.

Currently, there are two surgical techniques for performing the aforementioned removal operation: the so-called curettage (or curettage ) and the so-called radiofrequency ablation .

curettage

The removal of an osteoid osteoma performed through the curettage technique represents an "open-air" surgery (or traditional surgery); this means that it involves general anesthesia and an incision of the skin tissues where, below, lies the osteoid osteoma to be removed.

The peculiarity of the curettage is that, during its execution, the surgeon uses a special scraper tool (called a curette ), through which he scrapes the nodule that forms the osteoid osteoma.

The curettage technique is very effective; however, it presents some risks, which mainly depend on the use of general anesthesia and the practice of skin incision.

Being an invasive operation and to be performed under general anesthesia, the curettage for the elimination of an osteoid osteoma requires the patient to enjoy good health.

RADIO FREQUENCY ABLATION

Radiofrequency ablation for the removal of an osteoid osteoma represents an innovative surgical approach, which differs from the curettage in that it is less invasive. Its execution, in fact, provides a minimal skin incision, which is necessary for the surgeon to introduce the instrument necessary for the removal of the osteoid osteoma. To be more precise, this instrument consists of a radiofrequency probe, which, through the generation of a very high frequency electric current, generates such heat as to burn the undesired element.

The removal of an osteoid osteoma by radiofrequency ablation requires the use of a CT scan device, in order to guide the attending physician in the appropriate placement of the radiofrequency probe, close to the tumor mass.

Executable by an interventional radiologist or orthopedic surgeon, radiofrequency ablation for the removal of an osteoid osteoma is an effective procedure, lasting no longer than 2 hours and which does not always require the use of general anesthesia.

RECOVERY TIME FROM SURGICAL INTERVENTION

After surgical treatment of the osteoid osteoma, recovery times and return to normal daily activities depend mainly on two factors, which are:

The surgical technique adopted. Being more invasive than radiofrequency ablation, curettage has slightly longer recovery times;
The position of the osteoid osteoma. The incisions made in some anatomical sites use more time to heal compared to others operated elsewhere and this obviously lengthens the recovery time frame.

In general, however, recovery from a surgical operation to remove an osteoid osteoma occurs within a few days, as well as a return to normal everyday activities.

Prognosis

As previously stated, the osteoid osteoma is the protagonist of a completely spontaneous healing process. This aspect could lead to think of a positive prognosis of osteoid osteoma, except that:

The spontaneous resolution of an osteoid osteoma occurs over a very long period of time, which can range from a minimum of 6 to a maximum of (well) 15 years;
During its course, the osteoid osteoma can be responsible for such severe and intense pain that it profoundly affects the quality of life of the patient;
A very painful osteoid osteoma requires the use of surgery, which presents risks that are not always negligible.