LOBAK is a mobile app based on the knowledge and experience of neurosurgeon W. Robert Hudgins, M.D. This site explains and expands the help you get from the app LOBAK in learning the cause of your lower back pain and what to do about it.  It puts an expert in spine problems in your hands. Just answer some questions about your lower back and/or leg pain, do some simple tests on yourself as illustrated and you’ll learn the most likely cause of your pain and what to do next.


LOBAK uses a  unique classification system created by neurosurgeon Hudgins to tell you the odds that you have a lumbar disk protrusion (ruptured, herniated or extruded disk or disc, also called a herniated nucleus pulposus or HNP) and and if you haven’t already had an imaging study (CT, MRI, or Myelogram),  whether you need an imaging study (CT, MRI or myelogram). It then computes the predictive value of a positive or negative test result, in percent, of a disk protrusion, using Bayes’ theorem of conditional probability. The app then uses decision analysis to tell you if you should consider having surgery.

LOBAK can warn you when it’s urgent to see your doctor. It can detect many other causes of back pain, from simple lumbar sprain, to spinal tumor or fracture, spinal stenosis causing difficulty walking, infection, arthritis, and spondylolisthesis, and refer you to this website for further recommendations. Now available on the iOS App Store and Google Play Store.

The Problem of Lower Back Pain

Lower back pain has occurred in up to 80% of adult Americans at a cost of $50 billion annually.  It is second only to common cold symptoms in visits to a doctor. Most of the causes are simple sprains and strains of muscles.   

Many things can cause lower back and/or leg pain. The LOBAK app lists dozens of them. But if pain begins to go down the leg, lumbar spinal nerves are being irritated. It could be a spine fracture or growth, spinal stenosis or spondylolisthesis, but if those things are not present, the great majority of people with back and leg pain have a herniated lumbar disk. The LOBAK can give you a head start in finding probable causes and treatment of your back and leg pain or just back pain only.

The Problem of a Herniated Disc

A herniated disc can occur without causing pain and painful herniated discs will often heal themselves with time.  All imaging studies are imperfect with respect to the lumbar discs. Studies in persons without any back pain have shown herniated discs.  Those are obviously false-positives. Studies also fail to detect all herniated discs, the false-negatives. So the diagnosis of a herniated disc causing pain is uncertain, as is an opinion that no herniated disc is present to cause pain.

Non-operative, or conservative treatment of back pain includes many options, probably because they are often unsuccessful.  And pain improvement after treatment could have occurred without the treatment. With surgery, there is no way to prove that an operation was necessary, because a fragment of herniated disc when removed and sent for pathologic examination, looks no different from a normal disc.  So the best evidence that an operation was needed is that it provided prompt relief of pain. However, cases have been reported in which pain improved in a percentage of patients in which an operation found no herniated disc and nothing was done to the disc.

In lumbar disc herniations, diagnoses have likelihoods but no certainties.  The key is to consider the possible outcomes of surgery and work back toward evaluating test results and the patient’s symptoms and neuromuscular abnormalities to see if they reach the threshold of diagnosis for surgery.  That is what the LOBAK app does. Coming Soon for iOS and Android devices.