Pet Peeve: “High Index of Suspicion”

June 16, 2023 The Trauma Pro Leave a comment

How often have you heard this phrase in a talk or seen it in a journal article:

“Maintain a high index of suspicion”

What does this mean??? It’s been popping up in papers and textbooks for at least 30 years. And to me, it’s meaningless. You try to figure out that sentence!

An index is a number, usually mathematically derived in some way. Yet whenever I see or hear this phrase, it doesn’t apply to anything quantifiable. What the author is really referring to is “a high level of suspicion,” not an index.

This term has become a catch-all to caution the reader or listener to think about a (usually) less common diagnostic possibility. As trauma professionals, we are advised to do this about so many things, it really has become sad and meaningless. And don’t we all do this anyway?

Bottom line: Don’t use this phrase in your presentations or writing. It’s silly and doesn’t make any sense. And feel free to chide any of your colleagues who do. Please give us some concrete data so we don’t have to be so suspicious!

Reference: High index of suspicion. Ann Thoracic Surg 64:291-292, 1997.

Pet Peeve

Pet Peeve: Conflicts Of Interest

June 13, 2023 The Trauma Pro Leave a comment

For the longest time, one of my pet peeves has been potential conflicts of interest (COI) involving authors on research papers. There is no simple definition of the term “conflict of interest.” However, a simple way to think of it is a situation where one’s personal interests may influence their professional responsibilities.

Upton Sinclair said it more simply in a book he was writing in the 1930s:

“It is difficult to get a man to understand something when his salary depends upon his not understanding it!”

The corollary of this is more useful when applying to research:

“One can be led to believe anything when their salary depends on it.”

Psychological research has demonstrated time and time again that human behavior is easily influenced. Even receiving a tiny gift leads the receiver to perceive the giver favorably and to be more willing to reciprocate, even without being asked. Ever wonder why your hospital won’t let pharma representatives sponsor lunches anymore? Or even give you a pen? Believe it or not, these little things can change your attitude regarding their product. And even if you firmly believe you can’t be swayed, you can’t change the basic operating system in your brain. Your behavior will change.

We know that behavioral changes after receiving a small gift can be significant. What if the gift is not so small? What about a research grant? A position on an advisory board? Free drugs or devices for your research? Corporate stock? These can significantly improve one’s academic rank, job security, financial status, and more. Think about this with respect to my corollary quote above.

An interesting paper published by the Canadian Medical Association twenty years ago looked at industry-sponsored randomized controlled trials and how often they produced statistically significant positive results. The authors reviewed papers in eight leading surgical and five leading medical journals over three years. They applied a rigorous evaluation method looking for a positive correlation between industry support and study results, controlling for quality and study size.

The authors found that overall, positive results were nearly twice as likely in industry-funded studies. These numbers were even more pronounced when looking at surgical procedures and drugs. Drug studies were 5x more likely to be positive, and new surgical procedure studies were 8x more likely when receiving industry support.

Does this surprise you? It shouldn’t. There are numerous ways to design (manipulate) studies by playing with the characteristics of the study groups, statistical analysis, and even the wording of the manuscript. And at worst, the study could just be trashed, never to see the light of day at the author’s whim (or sponsor’s). Ever wonder why you (almost) never see a negative or even a neutral result in a study where the authors have received some benefit from industry? They are very frequently positive (or “non-inferior”).

Like other high-quality journals, the Journal of Trauma and Acute Care Surgery has recognized the potential dangers of COI and its impact on the integrity of the papers they publish. A publication in process from the journal editors outlines the new stance and policy regarding conflicts. They believe it is such a potential problem that they have revised their COI policy.

The Journal will now require detailed COI forms to be filed at the time of manuscript submission. The manuscript will only progress in the review process once received. Reviewers cannot see them but are encouraged to independently review data in physician payment databases. I’m not confident all reviewers will be this meticulous. If the editors believe a significant conflict exists, they may require revision or retraction. Egregious violations could even result in banning from publication.

Bottom line: It’s about time! More and more journals are cracking down on conflicts of interest. This doesn’t mean that they won’t accept manuscripts with such conflicts. It merely means that the authors must provide a detailed list of all their conflicts. It will then be up to you to gauge if these conflicts could have impacted the study and how large a grain of salt to keep on your desk as you read it and decide if it is believable.

References:

Association between industry funding and statistically significant pro-industry findings in medical and surgical randomized trials. Can Med Assn J, 170(4):477-480, 2004.
The Journal of Trauma and Acute Care Surgery Position on the Issue of Disclosure of Conflict of Interests by Authors of Scientific Manuscripts. Journal of Trauma and Acute Care Surgery, Publish Ahead of Print DOI: 10.1097/TA.0000000000004024, 2023.

Thorax

Delayed Presentation Of Right Diaphragm Injury

June 9, 2023 The Trauma Pro Leave a comment

Diaphragm injury from blunt trauma is uncommon, occurring in only a few percent of patients after high-energy mechanisms. They usually occur on the left side and are more frequently seen after t-bone type car crashes and in pedestrians struck by a car.

Blunt diaphragm injury on the right side is very unusual. Even so, it is more easily detected due to obvious displacement of the liver that can be seen on chest x-ray. Blunt injuries on the right side usually result in a large rent in the central tendon or detachment of the diaphragm from the chest wall. This allows the liver to herniate into the chest, and the chest x-ray finding is not subtle.

This image shows an acute herniation of the liver through the diaphragm. Due to the size of the liver, only part of it can typically fit through the rent. Radiologists call this the “cottage loaf” sign. Why? Here’s the bakery item it is named after. Get it now?

Thankfully, most of these injuries are identified in the acute setting. They must be addressed surgically because, if left untreated, more and more of the liver will slowly move into the chest resulting in respiratory problems in the long run.

Acute management usually consists of laparotomy to address both the diaphragm tear and any other associated intra-abdominal injuries. The liver should be reduced by sliding a hand next to it laterally into the chest cavity and pushing the dome downwards. The right triangular ligaments should be taken down (if they are not already destroyed) to mobilize the organ better so the diaphragm laceration can be closed. This is typically accomplished with some type of large (size 0) permanent suture. A chest tube will be needed to evacuate the iatrogenic pneumothorax created by opening the abdomen.

Chronic right diaphragm injuries are a different animal entirely. There is no longer any need to evaluate for intra-abdominal injury, so the procedure is usually performed through the chest. For smaller injuries, thoracoscopic procedures have been described that push the liver downwards and then either suture the diaphragm primarily or (more likely) incorporate a piece of mesh.

Larger injury requires conversion to an open procedure so more muscle power can be used to push the liver downwards to facilitate the repair. However, do not underestimate the adhesions that will be present between diaphragm and liver (and possibly the lung) in long-standing injuries. It may take some time to dissect them away. Rarely, a laparotomy (or laparoscopy) may be needed to assist for very large and complex injuries.

References:

Management of Delayed Presentation of a Right-Side Traumatic
Diaphragmatic Rupture. World J Surg 36:260-265, 2012.
Delayed Discovery of Diaphragmatic Injury After Blunt Trauma:
Report of Three Cases. Surg Today 35:407-410, 2005.

Abdomen

Guidelines For Diagnosis Of Diaphragmatic Injury

June 6, 2023 The Trauma Pro Leave a comment

In today’s post, I will review the diaphragmatic injury practice guidelines published by the Eastern Association for the Surgery of Trauma (EAST). I will follow this up on Friday with an interesting delayed diaphragm injury case.

Diaphragm injury is a troublesome one to diagnose. It is essentially an elliptical sheet of muscle that is doubly curved, so it does not lend itself well to diagnosis by axial imaging. The addition of sagittal and coronal reconstructions to a thoracoabdominal CT has been helpful but still has a far from perfect diagnostic record.

From an evaluation standpoint, there are several possibilities:

Observation – not generally recommended. It is usually combined with imaging such as a chest x-ray to see if interval changes occur that would indicate the injury.
Chest x-ray – this is not often diagnostic, but when herniation of abdominal contents is obvious, the patient most assuredly has an operative problem.
Thoracoabdominal CT scan – this technology keeps improving, especially with thinner cuts and different planes of reconstruction. Sometimes even subtle injuries can be detected. But this exam is still imperfect.
Laparoscopy or thoracoscopy – this technique yields excellent accuracy when the injury is in an area that can be viewed from the operative entry point chosen.
Laparotomy or thoracotomy – this is the ultimate choice and should be nearly 100% accurate. It is almost the most invasive and has more potential associated complications.

EAST reviewed a large body of literature and selected 56 pertinent papers for their quality and design. Then, they critically reviewed them and applied a standard methodology to answer several questions.

Here are the questions with the recommendations from EAST, along with my comments:

Should laparoscopy or CT be used to evaluate left-sided thoracoabdominal stab wounds? First, these patients must be hemodynamically stable and not have peritonitis. If either is present, there is no further need for diagnosis; a therapeutic procedure must be performed.
Left-sided diaphragm injuries from stabs are evil. The hole is small, and since the pressure within the abdomen is greater than the chest, things always try to wiggle their way through this small hole. It can remain asymptomatic if the wiggler is just a piece of fat, but it can be catastrophic if a bit of the stomach or colon pushes through and becomes strangulated. Furthermore, these holes enlarge over time, so more and more stuff can push up into the chest.
EAST recommends using laparoscopy for evaluation to decrease the incidence of missed injury. However, if the injury is in a less accessible location (posterior), the patient has body habitus issues or adhesions from previous surgery may lead to incomplete evaluation, laparotomy should be strongly considered.
Should operative or nonoperative management be used to evaluate right-sided thoracoabdominal penetrating wounds? Note that this is different than the last question. All penetrating injuries (stabs and gunshots) are included, and this one is for management, not evaluation. And the same caveats regarding hemodynamic stability and peritonitis apply. Again, it applies to both stabs and gunshots.
Unlike left-sided injuries, right-sided ones are much more benign. This is because the liver keeps anything from pushing up through small holes, and they do not tend to enlarge over time due to this protection. For that reason, EAST recommends nonoperative management to reduce operation-related mortality and morbidity.
Should stable patients with acute diaphragm injury undergo repair via an abdominal or thoracic approach? This question applies to any diaphragm injury that requires an operation, such as a right-sided penetrating injury or any blunt injury. EAST recommends an approach from the abdomen to reduce morbidity and mortality. However, since abdominal injury frequently occurs in these cases, an approach from the chest limits the ability to identify and repair abdominal injuries. Otherwise, you may find yourself doing a laparotomy in addition to the thoracotomy.
Should patients with delayed visceral herniation through a diaphragm injury undergo repair via an abdominal or thoracic approach? For years, the preferred approach for delayed presentations has been through the chest because the injury is easier to appreciate and repair. However, if ischemic or gangrenous viscera are present, it will be more challenging to manage and repair from the chest. EAST does not make a specific recommendation for this question and suggests the surgical approach be determined on a case-by-case basis.
Should patients with an acute diaphragm injury from penetrating injury without concern for other intra-abdominal injuries undergo open or laparoscopic repair? The quality and quantity of data addressing this question were very low, but EAST recommends laparoscopy to repair these injuries to reduce morbidity and mortality. This includes blunt injuries, which tend to be larger. There were some conversions to an open procedure, especially in the blunt cases. The usual caveats on exposure, injury location, body habitus, and previous surgery apply.

Reference: Evaluation and management of traumatic diaphragmatic injuries: A Practice Management Guideline from the Eastern Association for the Surgery of Trauma. J Trauma 85(1):198-207.

CNS

Time Is Spine: Spinal Decompression For Central Cord Syndrome

June 2, 2023 The Trauma Pro Leave a comment

Over the recent decades, there has been a huge push toward “evidence-based” medicine. Unfortunately, the available amount of high-quality literature is relatively low. And the field of neurotrauma is even less-represented than most.

Debates have raged over the years regarding the proper timing of surgical spine decompression in patients with spinal cord injuries. Many proponents of early decompression (within 24 hours) believe this may limit secondary injury to the cord. But there are also others who don’t buy into this idea.

Central cord syndrome is a special case of spinal cord injury. It is a partial injury, usually in the cervical spine. It causes varying degrees of pain, paresthesia, and paresis and usually affects the upper extremities more than the lowers.

Many neurosurgeons choose a “wait and see” attitude with central cord syndrome patients. However, a group of neurosurgeons spanning trauma hospitals in Canada, Philadelphia, and Baltimore published an interesting paper last year. They performed a propensity score-matched cohort study, comparing functional recovery in patients undergoing early vs. late decompression after sustaining a central cord injury.

They specifically selected patients from three national spinal cord injury databases who had a full ASIA impairment scale examination performed within 14 days of injury. Patients had to have AIS grade C or D, meaning that some motor function was still present, and had to show a major difference between upper and lower extremity motor strength.

Here are the factoids:

Of a combined dataset of 1692 patients, 300 met baseline criteria. However, only 186 were eligible for propensity score matching, with half in each study group (early vs. late decompression).
Follow-up data was only available in 148 patients, which was right at the limit of the authors’ power calculation
Early surgery was significantly associated with improved upper limb motor function recovery but not the lower extremity. Overall motor score was not improved.
There was no functional improvement after late surgery
Patients with higher ASIA score (D) showed no improvement, regardless of surgical timing
Patients with AIS C lesions had significant recovery of their motor score in both upper and lower extremities but not their FIM motor score
A higher percentage of early-surgery patients achieved complete independence, especially those involving upper extremity function. However, this did not reach statistical significance.

Bottom line: Spine decompression timing remains very controversial, with every neurosurgeon having their own opinion. Unfortunately, this study was borderline underpowered, which may have weakened its results.

Several important trends were noted, however. First, early surgery did have an impact on functional recovery, especially in the upper extremities. This is especially important because use of the hands is critical to functional independence. But the most exciting result was the trend toward a higher percentage of patients achieving complete independence after early surgery. To be clear, this was just a trend and did not achieve statistical significance.

It’s time to start working with our neurosurgery colleagues and nudging them toward considering earlier surgery on this subset of spinal cord injury patients. It will take time and education, but these patients will actually be able to thank us, especially if they are actually able to shake our hands!

Reference: Early vs Late Surgical Decompression for Central Cord Syndrome. JAMA Surg. 2022;157(11):1024-1032. doi:10.1001/jamasurg.2022.4454

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