Haller Index for Pectus Excavatum
The Haller Index is an easy mathematical calculation to measure the severity of the pectus excavatum deformity.
It is also known as pectus index.
Throughout the years, the Haller Index has been helpful for surgeons to rate the severity of the pectus excavatum deformity.
In this chapter, I'll discuss about how this mathematical calculation was invented, whether it provides accurate information, and much more.
Over the years, pectus excavatum awareness has increased.
People who suffer from the deformity are conscious of the negative health effects it can cause.
Because of that, they are asking for medical treatment.
Surgeons needed some directions to determine whether the patient's health is severely affected by the deformity and demands immediate surgery.
How IT Was Invented
The Haller Index proved to be effective in what the surgeons were looking for.
It was created in 1987 by Jacob Alexander Haller Jr., who was an American pediatric surgeon, all together with Sandra S. Kramer and Steven A. Lietman.
They developed this calculation in Baltimore, Maryland.
Generally, patients with a higher Haller Index would benefit more from surgical correction.
On the other hand, patients with a lower HI don't require surgery because the deformity is probably just cosmetic and doesn't affect the internal organs.
Surgeons were seeking for a simple way to measure the severity of the pectus excavatum deformity. The Haller Index proved to be effective in doing that.
3 Measurement Methods
The Haller Index can be measured in three different ways.
Up until recently, doctors thought the most accurate way to measure the severity of pectus excavatum was a computed tomography (CT) scan.
A 2010 study proved the differences between the radiographic Haller Index and CT Haller Index are statistically negligible.
They concluded that the CT Scan wasn't required for calculating the severity of the pectus excavatum deformity.
A simple two-way chest radiograph was safer and just as effective.
Now it is a common practice for surgeons to use chest X-rays, and not CT scans, mostly because of decreased radiation exposure on the patients.
All three techniques for Haller Index measurement are used. However, a chest radiography is proven to be just as effective as a CT Scan.
In simple terms, the Haller Index measures how wide (transverse diameter) the chest is, compared to its depth (anterior-posterior diameter).
After a CT scan, surgeons divide the distance between the left and right rib (A), with the distance between the spinal cord and the sternum (B).
If distance A is 90 mm, and distance B is 20 mm, then the Haller Index will be 4.5, which is considered severe.
That's how you calculate the Haller Index.
What is a Normal Score
As stated by this research, a typical, flat-chested person has a HI of about 2.5 to 2.7.
Ranges from 2.5 to 3.0 are considered a slight case of pectus excavatum.
HI ranging from 3.0 to 3.25 is moderate.
All ranges higher than 3.25 are very serious and require treatment immediately.
How a Person with High HI Feels
The heart of a person with a Haller Index > 3.25, is probably displaced to the side.
Also, the right lobe of the liver can be squeezed by the malformed ribcage.
The indented breastbone is pushing the internal organs inward.
These patients also have everyday pain in the chest and back. Sometimes the pain is very bad, and sometimes it is tolerable.
The pain is usually concentrated around the protruding ribs, the deepest part of the chest.
Lots of pectus excavatum sufferers with a Haller Index higher than 3.25. said the pain feels like you're about to have a heart attack.
The back pain makes it hard for you to bend over, twist side-to-side.
If you have a job that demands lots of physical activity and lifting stuff, the pain is aggravated.
It goes to the point that it becomes hard to swallow.
Surgeons believe the severe indentation of the chest can press against the esophagus, which makes swallowing harder.
If a person has a high Haller Index, let's say in the range above 4.0, then he is probably having sharp chest and back aches.
The biggest disadvantage of the Haller Index as a regular severity measurement is that it isn't determined consistently.
Surgeons always face significant variations in the Haller Index estimation methods.
A change in any of these three variables can yield a different Haller Index score.
Small changes in the measurement technique can be the difference between undergoing surgery or following a non-surgical approach to repair the deformity.
In some cases, a patient who has a severely inverted chest that affects the lungs and heart can have a lower HI than a patient who used a different measurement technique.
The second patient with a higher HI score can only have a cosmetic deformity that doesn't affect his organ functioning.
The first patient won't undergo a surgery because the Haller Index isn't high enough.
Then, he will try to rely on physical therapy and other non-surgical treatments to fix the condition.
However, this will be a slow and tough process that may take a few years until he sees a full correction.
The second patient with a higher HI score will undergo a surgery that will probably require two titanium bars to be inserted below his sunken breastbone.
He will need to live with the bars for about three painful years. This will stop him from playing contact sports and living life to the fullest.
In this case, a surgery wouldn't be the best option.
The first patient requires quick surgery because the condition is causing him severe health problems.
Insurance Companies Don't Cover Surgery Costs
Additionally, most insurance companies don't cover the costs of a pectus surgery if the Haller Index is lower than 3.25.
This is the biggest problem with the Haller Index measurement.
For example, an 18-year-old with congenital pectus excavatum sufferer that has exercise intolerance and shortness of breath will be denied from taking financial coverage for surgery, if the Haller index is 3.1.
The shortness of breath and physical weakness will become more intense when he becomes 30 years old.
That will require surgery to repair the deformity because it will probably lower the patient's lifespan.
However, the Haller Index will remain at 3.10. The patient's surgical coverage will get denied again.
Surprisingly, this is quite a common situation.
The Haller Index mesurement can be inconsistent. Also, the insurance companies aren't willing to cover the costs for surgey for patients with a HI lower than 3.25.
Cut Off Value
In a book about chest wall deformities published in December 2015, 334 pectus deformities specialists were surveyed.
More than 50% of them stated the threshold of 3.25 to be inaccurate.
Plenty of surgeons agree that the severity of pectus excavatum shouldn't be divided into arbitrary groups (lower or above 3.25), especially when so much is at stake.
Relying on the Haller Index alone, surgeons can't predict how negatively the patient is affected by the deformity, both psychologically or physically.
In this study, surgeons Robert Eisinger and Hans Pilegaard agree with the opinion of more than half of the chest wall deformity specialists, and don't measure the Haller Index at all.
They also ask health coverage companies to examine other factors, and not just the Haller Index when it comes to covering the surgery costs.
Plenty of surgeons agree the requirement to have a Haller Index score above 3.25 as a threshold for a surgery to be innacurate.
The Problem With HI
From a medicinal point of view, it is completely incorrect for the pectus excavatum surgical procedures like the Nuss or Ravitch, to be planned only for people with a Haller Index greater than 3.25.
Lots of patients and surgeons want the cut-off point to be set as low as possible.
That way, patients that feel negative physical and mental effects caused by the deformity, can be reasonably operated.
Take the example of the BMI (body mass index) calculation.
A lot of informational websites on the internet determine obesity only based on BMI calculations.
For example, take Robert Harting, who is a German Olympic discus thrower. During his career, he has won 7 Gold Medals.
When he won his last gold medal in Zurich, in 2014, he was 30 years old, standing at 2.01m (6 ft 7 in), weighing 126 kg (278 lbs).
If you use NIH's certified BMI Index, his Body Mass Index is 31.3.
According to the World Health Organisation BMI categories, a person is obese if he has a BMI of 30 or greater.
How can an Olympic athlete who is in the prime of his career, winning Gold medals, year by year, be categorized as obese?
Certainly, about 90% of all people find their BMI to be accurate. But what about the remaining 10%?
It is not any different from the Haller Index calculation.
PE Severity Can't Be "Mathematically" Calculated
The severity of pectus excavatum and how critically it is affecting the vital internal organs cannot be calculated so easily.
In some cases, the HI doesn't provide any value.
You can’t rely on this mathematical calculation alone. Your doctor needs to pay more attention to how the organs in your body are positioned.
The positioning of the heart and lungs is crucial.
See whether your lungs are squeezed or whether your heart is displaced to the side.
That's how you see if the pectus excavatum deformity is causing you health troubles.
The surgeon giving you a Haller Index score is the same as if Robert Harting went to the doctor to check his BMI score.
The HI can't tell everything about the pectus excavatum severity. You have to check the internal organ structure to see whether the deformity is harmful. It is similar with BMI in telling a patient whether he or she is in the healthy weight range.
3D Optical Imaging - Alternative Technique
In October 2018, a couple of medical doctors and Ph.D.'s at Stanford University, California, published a study that proves three-dimensional scanning to estimate the severity of chest wall indentation, without any radiation exposure.
In the study, the patient's chests were scanned with a 3D structured light camera.
3D Optical Imaging Technique seems promising as a great alternative to the Haller Index measurement of pectus excavatum severity.
It would be beneficial to have a few extra studies on this subject to further establish this technique.
It is scientifically proven the 3D Optical Imaging to be a great alternative to the Haller Index.
Nowadays a simple chest radiograph or a CT scan are the two most commonly used ways to measure the Haller Index.
Even though most surgeons agree on its usefulness, they also agree it can give the wrong picture about the seriousness of the deformity.
To know whether the deformity affects your internal organs, you must see their internal structure.
For example, take two people who have a HI of 3.8.
The internal organs in one patient may not be affected at all, and in the other they can be pushed to the side, causing cardiac and respiratory system problems.
At the end of the day, you won't lose anything if you know the score of your Haller Index. However, make sure you also inspect the positioning of your internal organs, regardless of the HI score.
That's the best way to know whether you need surgery or not.