Sacral dimple: what is it and how can it affect my child's health?

Some babies have a small indentation in the lower back. This area is also called lumbar region or sacral zone, because the sacrum bone is the one that is located there. Hence this small notch is called sacral dimple.

The sacral dimple can be a simple fossa that does not cause discomfort or symptoms. However, sometimes this depression connects with the spinal canal, so it can cause problems at the nervous system level. Therefore, In this article we explain everything you need to know about the subject and how it is treated.

What is a sacral dimple?

As we have mentioned, a sacral dimple is a notch or indentation that appears in the lower back. It is present from birth. As explained by Mayo Clinic specialists, it is usually located just above the gluteal crease.

The truth is most dimples of this type are harmless. However, a percentage is associated with spinal dysraphism. According to an article in Acta Pediátrica, spinal dysraphism refers to certain congenital anomalies that cause the incomplete closure of certain structures, such as the spine.

It is a heterogeneous group of malformations that cause the neural tissue to be more exposed. In this same study they state that Between 40 and 95% of babies with spinal dysraphism have some alteration in the skin. In many of these cases, this alteration can be a sacral dimple.

Above all, it is important to suspect that the sacral dimple is dangerous if it is near a lock of hair or there are color changes in the nearby skin. The problem is that in these cases, due to the neural alteration, there may be neurological, urinary, rectal or even orthopedic alterations. That is why it is essential to distinguish and treat it.

Types of sacral dimple

A sacral dimple can be typical or atypical. This simple distinction is what makes it possible to differentiate whether it is a benign situation from something serious. A typical or simple sacral dimple is one of small size, which is found in the crease between the buttocks.

Usually, does not exceed five millimeters in diameter. Also, they are close to the edge of the anus. They are quite frequent and do not imply any type of risk of dysraphism. In fact, it is estimated that they appear in almost 5% of healthy newborns.

On the other hand, we found the atypical dimples. They are larger. They are more than half an inch deep and are further from the anus. They can become close to the sides.

An atypical dimple is considered a risk factor for spinal dysraphism. When they are very deep, there may be abnormal communication with the spinal canal. The spinal canal is a very sensitive structure through which numerous nerve fibers run.

Therefore, This communication can cause spinal and neurological damage. These types of dimples can be accompanied by changes in skin color, bumps, or even areas of unusual hair growth.

What is the difference with the pilonidal cyst?

As explained by the University of Navarra Clinic, a pilonidal cyst is a cyst that contains hairy formations inside. As with the sacral dimple, occurs in the intergluteal area, just above the buttocks.

What happens in the pilonidal cyst is that hair, cells, waste substances and liquid accumulate, leading to a collection. It usually develops after birth. It is more common in men and, on many occasions, it becomes infected. This results in severe pain and swelling.

Causes of sacral dimple

The truth is that, to this day, the causes of the sacral dimple could not be identified. It is known that it is something congenital, that it is present from birth. This, as we have pointed out in the previous section, allows it to be distinguished from the pilonidal cyst.

Atypical dimples can be derived from that closure defect of midline structures. However, it is also not known exactly why this event occurs.

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What symptoms does it produce and how is it diagnosed?

Generally, sacral dimples do not produce any symptoms. This is because they are mostly simple dimples. It is just a skin disorder on the lower back.

However, an atypical sacral dimple can be associated with certain symptoms. It depends on whether it is really an indicator of spinal dysraphism. Therefore, to detect it, a thorough physical examination is required.

It is essential to measure and verify the characteristics of the dimple. If it is very large or deep, a series of complementary tests must be carried out to study it. The same is true if more dimples appear, there is discoloration of the skin or it is located too far from the anus.

According to a study published in the Archives of Disease in Childhood, ultrasound is a method that allows you to study dimples. When abnormalities are seen in it, it is estimated that there is six times more likely that there is some type of spinal problem.

Ultrasound is a preferable technique because it is inexpensive, fast, and safe. However, if there are doubts about the diagnosis, an MRI may be done. It allows to study tissues with greater precision.

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Possible complications

The complications derived from a sacral dimple appear in the case of those atypical. May be related to spina bifida or tethered spinal cord syndrome, among other pathologies.

Spina bifida is a congenital malformation. What happens is that the neural tube does not close properly. There are different types, but the one that is related to the sacral dimple is spina bifida occulta.

It is characterized because there is a small hole in the column. This gap appears because the spinal column does not develop at that point. It may not produce symptoms and is usually detected in adolescence or adult life.

On the other hand, Tethered spinal cord syndrome occurs when there is scar tissue that anchors the spinal cord. It can lead to urinary and fecal incontinence, lower limb weakness, or even difficulty standing.

Sacral dimple treatment

For a simple sacral dimple, no specific treatment is necessary or exists. The only essential thing is to prevent dirt from accumulating in this area. Otherwise, infections can occur, since they are very close to the anus and there may be contamination by intestinal bacteria.

Therefore, when they are still babies, it is essential to clean the area well and be careful with diapers. In the event that the dimple is atypical, some treatment may be required depending on the risk.

It is necessary that each case is reviewed and studied by a doctor. In children with neural tube closure defects, surgical techniques may be necessary to alleviate the defect.

How do you proceed according to its status?

Ideally, all newborns should be thoroughly screened. If a sacral dimple is seen, an initial study of it should be done. In this, the dimple is measured and other signs or abnormalities are looked for around it.

If everything else is normal, the child is in good health, and the sacral dimple is small, nothing more needs to be done. Conversely, If there are any warning signs or the dimple is atypical, it is normal for the child to be referred to a specialist.

It will be essential to explore the dimple more accurately. In addition, it will be investigated if the baby may have any neurological alteration or developmental defects. Similarly, depending on the results, the best treatment for each case will be considered.

What we must remember is that most sacral dimples are simple. They are only a small alteration in the skin. However, it is essential to rule out that it is a neurological problem. That is why it is always advisable to consult a doctor.