Sacral Dimple

SACRAL DIMPLE

The sacral region is at the bottom of the spine. It is a triangular bone and consists of five segments fused.
Sacral dimple
Anatomy of Sacral Spines (Source: https://my.clevelandclinic.org/health/articles/10040-spine-structure-and-function)
A sacral dimple is a pit at the back of the child in the Sacral region. It is not common in newborns, but we can rarely experience it in children. It is usually something by birth.

WHAT IT REALLY IS:

It is a small indentation (dent) in the lower back near the crease of the buttocks. This mark does not cause any health issues. But somehow, in rare cases, it can be the root cause of some underlying problems in the spine.

How common is it?

It is not rare. Out of 100 babies, roughly 3-8 percent of babies are born with a sacral dimple.

SYMPTOMS:

It looks like a superficial pit, a dent in the lower back between the bottom’s creases (buttocks). Usually, it is an empty track, and nothing comes out of it. Sometimes, if this pit is longer, there may be a discharge of pus from it. Also, sometimes, there may be a discharge of some fluid seen from this pit.

sacral dimple

CAUSES BEHIND SACRAL DIMPLE:

Medically and scientifically, there is no reason found which causes this disease. It is congenital, which means it is by birth formed in the womb of the mother.

TWO MAJOR COMPLICATIONS:

There are two major complications found in Sacral Dimple, which should be ruled out and acknowledged initially.

A) SPINA BIFIDA:

Spina bifida is a condition that affects the spine and is usually found by birth. It is a form of Neural Tube Defect (NTD). It appears when the spine is not totally or completely formed in the baby. In this condition, the spines are opened and not fused. In children having this issue, we plan for MRI and check for this condition.
sacral dimple
Source: https://en.wikipedia.org/wiki/Spina_bifida

B) TETHERED CORD SYNDROME:

Our body’s spinal cord hangs freely from top to bottom in our body within the Spinal canal. The tissue which is attached to the spinal cord limits its movement describes the Tethered cord Syndrome disorder. Spinal cord nerves grow attached to a spot on the spine by “Tethered spinal cord.” It limits or restricts the natural ability of the spine to move. It is usually ruled out by a pediatrician to operate or not by its size and location.
Sacral dimple
Source: https://me-pedia.org/wiki/Tethered_cord_syndrome
The common presentations of Tethered Cord Syndrome are:
a)      Numbness and weakness in legs.
b)      Foot or Spinal deformations.
c)      Difficulty in walking.
d)     Lower back pain.
e)     Bowel or bladder incontinence
There are some attributes or indications which show spinal problems due to the presence of sacral dimple.
(i) Nearby Tuft or bunch of hair
(ii) Extra skin or skin tag below the spinal cord
(iii) Discoloring of skin nearby
(iv) Bruising of skin near that area
(v) Swelling in the affected area
(vi) A dimple larger or deeper than 5 millimeters
(vii) Tenderness
If any of the above conditions is present along with sacral dimple, visit your Pediatrician or Pediatric Surgeon.

WHEN AND HOW IT CAN BE RULED OUT?

If there is some concern and doubt regarding the sacral dimple, it can be ruled out by having an Ultrasound of the spine. It is usually carried within 3 or 4 months after the child is born.
After the doctor doubts, he may advise an Ultrasound and testing of some problems. The baby may undergo further evaluation and diagnosis for treatment. This can include Magnetic Resonance Imaging (MRI).

ALERT SIGNAL FOR PARENTS:

Parents should immediately consult the doctor when they notice any of the following:
(i) Redness on the skin.
(ii) Swelling nearby. 
(iii) Drainage of pus.

TREATMENT OR SURGICAL PROCEDURE:

If we observe any indication of infection in this area, we treat it with antibiotics. However, If there is an abscess, the child may need minor surgery to drain the pus.
If there is any indication for surgery, we do it as a day-care surgery. We perform this surgery in general anesthesia. It is a medium type of surgery. If there is an attachment to the spinal cord, then we involve Neurosurgeon also. In that case, it is major surgery. 
If it is a simple sacral dimple and base is visible, then we advise observation. We advise to keep it clean.
A sacral dimple with its base visible
A sacral dimple with its base visible (so no surgery advised)

CAN WE SEE IT IN ADULTS AS WELL?

Like in children and neonates, we may also find it in adults. In adults, it occurs when loose hair pushes into the skin. 

CONCLUSION:

From the medical point of view, the sacral dimple is not a disease, but in the case of the above-mentioned symptoms, one should consult a doctor.

Related Links:

Some FAQ's About Sacral Dimple

Sacral dimples are seen in 2-4% of births, although the cause is unknown. In most cases, they appear as a minor abnormality and disappear after birth. However, they can indicate a deeper spinal abnormality and be present later in life with no problems to those carrying it.

A sacral dimple is something babies are born with. A sacral dimple will not go away, but as your child grows older it becomes less noticeable. Most sacral dimples don’t cause any problems and the baby won’t even notice-although when they’re newborns their parents may worry about them a little bit more!

Scientists have not determined for sure what causes sacral dimples, but it is likely that a genetic condition may be the cause. If you also experience other symptoms such as bruising, tufts of hair or skin tags- then there could be an underlying issue with your spine. But most are benign and harmless.

Sacral dimples are fairly common in infants and usually benign, but they may be indicative of a neural tube defect.

Doctors usually recommend surgery for sacral dimples that are accompanied by a nearby tuft of hair, skin tag, or certain types of skin discoloration. Sacral dimples which do not have any symptoms alongside them are harmless and don’t require treatment.

Sacral dimples can be a sign of an underlying spinal issue. These include spina bifida, tethered spinal cord, etc., and most sacral dimple don’t cause any problems at all.