The Haller Index is a straightforward mathematical calculation to measure the severity of the pectus excavatum deformity. It is also known as the Pectus Index.
Throughout the years, the Haller Index has been helpful for surgeons to rate the severity of the pectus excavatum deformity.
In this post, I'll discuss 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 adverse 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 was severely affected by the deformity and demanded immediate surgery.
HOW WAS IT INVENTED
The Haller Index proved effective in what the surgeons were looking for. It was created in 1987 by Jacob Alexander Haller Jr., an American pediatric surgeon with Sandra S. Kramer and Steven A. Lietman. They developed this calculation in Baltimore, Maryland.
Generally, it is believed that 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.
3 MEASUREMENT METHODS
The Haller index can be measured in three different ways.
- CT Scan
- MRI (Magnetic Resonance Imaging)
- Chest Radiography
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 insignificant.
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. It is common for surgeons to use chest X-rays and not CT scans, primarily because of decreased radiation exposure to the patients.
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 space 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, 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 2.7 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 considered severe 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 malformed ribcage can squeeze the right lobe of the liver.
The indented breastbone pushes the internal organs inward. These patients also have everyday pain in the chest and back. Sometimes the pain is horrible, and sometimes it is tolerable.
The pain is usually concentrated around the protruding ribs or the deepest part of the chest. Some 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 and twist side-to-side. The pain is aggravated if you have a job demanding lots of physical activity and lifting.
It goes to the point that it becomes hard to swallow. Surgeons believe the severe indentation of the chest can press against the esophagus, making swallowing harder.
BIGGEST PROBLEMS WITH HALLER INDEX
The most significant disadvantage of the Haller Index as a regular severity measurement is that it needs to be determined consistently. Surgeons always face substantial variations in the Haller Index estimation methods. A change in these three variables can yield a different Haller Index score.
- The transverse plane is used to estimate the anterior-posterior depth of the dent in the chest (the most profound point of the dent in opposition to a standardized point).
- Whether the patient is inhaling or exhaling when the calculation is performed.
- Which medical imaging modality is used (MRI, CT Scan, or Chest Radiography).
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 with a severely inverted chest that affects the lungs and heart can have a lower HI than a patient with 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 surgery because the Haller Index isn't high enough.
Then, he will try to rely on physical therapy and other non-surgical treatments to improve the deformity. However, this will be a slow and laborious process that may take a few years until he sees a full correction.
The second patient with a higher HI score will undergo surgery requiring two titanium bars or more to be inserted below his sunken breastbone. He will need to live with the bars for about three years.
This will prevent him from playing contact sports and living life to the fullest. The problem is that the second patient could improve the deformity faster, cheaper, and pain-free by using vacuum bell therapy and other non-surgical options.
In this case, surgery wouldn't be the best option. The first patient requires immediate 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 a big problem with the Haller Index measurement.
For example, an 18-year-old with congenital pectus excavatum with exercise intolerance and shortness of breath will be denied 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 3.1. The patient's surgical coverage will get denied again. Surprisingly, this is quite a common situation.
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 and physically.
In this study, surgeons Robert Eisinger and Hans Pilegaard agree with the opinion of more than half of the chest wall deformity specialists that don't measure the Haller Index. They also ask health coverage companies to examine other factors, not just the Haller Index, when covering surgery costs.
My Thoughts about HALLER INDEX
From a medicinal point of view, it is entirely 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. Many patients and surgeons want the cut-off point set as low as possible.
That way, surgeons can reasonably operate on adverse physical and mental effects caused by the deformity.
BMI VS. HALLER INDEX COMPARISON
Take the example of the BMI (Body Mass Index) calculation. Many informational websites on the internet determine obesity only based on BMI calculations. For example, take Robert Harting, 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) and 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 in the prime of his career, winning Gold medals yearly, be categorized as obese?
Indeed, 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 affects 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 your heart is displaced to the side. That's how you see if the pectus excavatum deformity is causing you health troubles.
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 three-dimensional scanning can estimate the severity of chest wall indentation without radiation exposure.
The study scanned the patient's chests 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 additional studies on this subject to establish this technique further.
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.
You must see their internal structure to know whether the deformity affects your internal organs. 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, ensure you also inspect your internal organs' positioning, regardless of the HI score. That’s the best way to know whether you need surgery or not.