Attorney toolbelt

The attorney has many tools for an effective defense including the claims representative, witnesses, evidence, surveillance and more.

Risk Management

The Attorney Perspective: Preexisting Herniations

A recurrent issue in chiropractic negligence litigation is the herniation that preexists a plaintiff patient's care by a defendant chiropractor. Typically, that condition worsens during the chiropractic care period naturally and is not diagnosed until after that care. The defense goal is to show that although the condition is diagnosed after the care, it is also unrelated to the care: to rebut a claim against the chiropractor based on the legal fallacy of "post hoc ergo propter hoc."


The chiropractor’s attorney should identify the herniation issue early in the litigation and seek immediate expert review of it. The chiropractic care usually hinges on it. Disc herniation is a defensible issue with good experts, with a client who could explain the care and the plaintiff's preexisting condition, with concessions from the plaintiff’s experts and with a simple causation theory. Good surveillance of the plaintiff challenging claimed damages also bolsters the case’s credibility.

Case Example

Tim Stern presented to William Petra, D.C., in April 2011 complaining of recent neck pain and stiffness, and pain radiating into his left shoulder and arm. Dr. Petra’s evaluation of Tim included positive cervical distraction and compression tests, and his working diagnosis was cervical radiculopathy. An April 2 X-ray showed spondylosis at C5–6 with foraminal osteophyte production and bilateral foraminal narrowing. Tim was referred for a CT scan in lieu of an MRI because he had cardiac stents placed recently. An April 8 CT showed bilateral joint hypertrophy at C5–7 and mild bilateral neural foraminal stenosis at C5–6. Also, an April 15 EMG nerve conduction study revealed bilateral C5–6 radiculopathy and carpal tunnel syndrome.

Dr. Petra treated Tim with light manipulations and IDD decompression therapy until late May 2011, when Tim’s condition worsened. A May 28 MRI without contrast revealed a large soft-tissue mass in the ventral epidural space from C5–7, causing cord compression and spinal stenosis at C6–7. Also, a June 3, 2011, MRI with contrast revealed a large disc extrusion at C5–6 and severe spinal stenosis at C5–6 and C6–7. Tim claimed that Dr. Petra was negligent in treating him with the decompression therapy, considering his symptoms, and that the treatment caused his herniation, cord compression and need for surgery.

The potential problem was there was no pretreatment MRI of the area to consider for a baseline comparison.

To attack causation, Dr. Petra’s counsel retained a neurosurgeon and a neuroradiologist. The neurosurgeon said Tim was a candidate for conservative chiropractic care. He explained that Tim responded well to conservative chiropractic care at first, but later required surgery to remedy a long-standing neck and back problem that worsened during the treatment period but was unrelated to the chiropractic care. He said Dr. Petra’s decompression therapy could not have caused Tim’s C5–7 herniation because Tim’s spine was already compressed and because the IDD therapy was specifically designed to relieve such compression.

Dr. Petra’s neuroradiology expert referenced the films taken before the treatment period and used them to discuss the preexisting condition that worsened, namely the herniation. He noted that the April 2 X-ray showed straightening of the cervical spine, with mild spondylosis. He found that the April 8 CT revealed soft tissue in the anterior epidural defect on the right side of the thecal sac and no high-density material in the spinal canal, supporting a finding of extruded disc material at C5–7. He then compared those reads to the May 28 MRI, which showed a large anterior epidural defect at C5 to C7, a narrowing of the spinal canal and cord compression.

The neuroradiologist’s opinion was important because it supported a preexisting herniation despite there being no preexisting MRI for a baseline comparison.

To attack liability, Dr. Petra’s counsel retained a chiropractor versed in IDD decompression therapy. That expert explained that Dr. Petra’s neurologic and orthopedic exams of Tim were within chiropractic standards. He noted that Dr. Petra’s manipulations of Tim’s spine and use of IDD decompression were appropriate based on the foraminal stenosis and compression at C5–6. He also referenced literature supporting the use of decompression therapy for disc herniations, degenerative disease and spinal stenosis: in other words, Tim’s condition.

The chiropractic expert’s clinical picture was instrumental in supporting the neurosurgery and neuroradiology experts’ diagnostic story.

Tim said he was taking OxyContin, Oxycodone and Lyrica for pain that limited his movements and activities. He also claimed that he suffered from imbalance, had trouble lifting certain objects, and could not play with his son or do yard work. Shortly before trial, Dr. Petra’s counsel retained an investigator whose surveillance showed Tim fighting with another man, playing with his son, standing for long periods, and running, walking and bending with no issue. Counsel showed that footage to the jury.

Dr. Petra testified well at his deposition and at trial. He explained chiropractic simply and passionately. He discussed how he examines patients and develops care plans for them based on the findings. He explained the tests he uses and the films he requires before treating patients. He referenced spinal models to enhance his testimony. And he explained his training and experience with decompression therapy, how the IDD machine works and why Tim was a candidate for it and could not have suffered injuries as a result of being treated on it.

Dr. Petra taught the jury how he treated Tim with light spinal adjustments and IDD therapy. He discussed how Tim responded to that care in terms of his pain level, which decreased from 8/10 to 5/10. He explained that although Tim had two flare-ups (muscle spasms) during the treatment period, his pain level continued to decrease from 5/10 to 4/10 until May 26, when his pain level increased to 6/10. He said he referred Tim for an MRI based on that worsened pain and his concern for Tim.

Dr. Petra’s likability and grasp of chiropractic bolstered his credibility; Tim’s apparent exaggeration of his injuries and inability to connect the causation dots weakened his.

Tim’s chiropractic expert criticized Dr. Petra for not securing Tim’s informed consent for manipulative and decompression therapy. He believed the decompression therapy caused Tim’s C5–6 disc herniation. Dr. Petra’s counsel deposed that expert and had him concede that he had never used a decompression machine or known of one causing a herniation, and had understood that it was meant to treat herniations. He also conceded that the records and testimony supported that Tim benefited from the decompression therapy.

Tim’s neurosurgery expert also believed that Dr. Petra’s decompression treatment caused Tim’s herniation and cord compression, leading to his surgery. Dr. Petra’s counsel also deposed that expert, who could not identify when or how the IDD therapy caused the herniation or what level of magnitude it had on Tim’s spine. He said he could not diagnose a herniated disc on a CT. But he conceded that an MRI was contraindicated on April 8 due to Tim’s recently placed stents. And he agreed that Dr. Petra’s neuroradiologist’s interpretation of the CT would support a preexisting herniation that evolved during Dr. Petra’s care of Tim.

Challenging the factual predicates of Tim’s experts’ opinions at their depositions and securing necessary concessions from them provided confidence that the case could be tried.

Tim conveyed a high settlement demand based on the severity of his injuries and his claimed limitations; Dr. Petra refused to settle believing his care was proper and noninjurious.

The trial lasted three weeks and ended with a unanimous defense verdict. The jury believed Dr. Petra’s neuroradiologist’s opinion that the herniation was present on the April 8 CT scan, despite the initial radiologist’s report not mentioning it. The jury understood Dr. Petra’s neurosurgeon’s explanation that the herniation progressed during the treatment period despite—and not because of—Dr. Petra’s chiropractic treatments. The jury also accepted Dr. Petra’s chiropractor’s testimony on how and why Tim was a candidate for decompression therapy and manipulations, even with a cervical spine herniation present.


The information in the NCMIC Learning Center is offered solely for general information and educational purposes. It is not offered as, nor does it represent, legal or professional advice. Neither does this information constitute a guideline, practice parameter or standard of care. You should not act or rely upon this information without seeking the advice of an attorney familiar with the specific legal requirements of the state(s) in which you practice. If there is a discrepancy between the site and an insurance policy you have with NCMIC, the policy will prevail.