53-year-old gentleman who is seen at the emergency room for fatigue and tachycardia. A TEE is performed and he is found to have endocarditis and mitral valve abnormalities. A minimally invasive MV replacement w/ bypass (R femoral approach) is scheduled for approximately 8 days later. This is performed with right groin cannulation and intercostal block. Bypass time was 138 minutes. This was not robotically assisted.
There are no documented complications intraoperatively.
The record we currently have does not have a specific note detailing the cannulation procedure, however it was performed by the cardiothoracic surgeon. We do have an event/medication log from the operation, however we did not see anything directly related to this complaint so it was not included.
We have attached a screenshot of the U/S guidance for the groin access.
Later on that evening post-op, PC has no ability to lift his right leg. There's concern for nerve damage by the surgeon to the femoral nerve, as he also develops a post op seroma to the right groin area. Multiple consultations theorize that the injury is most likely due to the cannulation due to no other discernible explanation, despite multiple assessments and diagnostics (PC was made a stroke alert out of precaution, no findings. Bedside nerve testing, etc). PC claims never had any issues with this leg prior.
He is discharged approximately one week later. He completes a neurology follow up consultation and physical therapy. MRI of the brain and CT show no abnormalities.
9 months postoperatively, PC has an EMG nerve study completed. Results show right perineal, posterior tibial and bilateral sural neuropathy. Also suggestive of peripheral neuropathy. There's a denervation in the right vastus medialis muscle, right femoral neuropathy/lumbar plexopathy and no recovery in the right vastus medialis muscle.
This study is attached for review.
We are looking for an opinion concerning the femoral nerve injury in relation to the cardiac procedure. If you request any additional information or have questions please let us know.
Thank you in advance for your time and opinion.
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Do you believe there might have been medical error?
Femoral nerve injury is a known complication of femoral cannulatikn which is a standard form of cannulation Error could be present if a hematoma was unrecognized and left alone or if the deficit was diagnosed late
Do you believe there might have been causation (i.e. the medical error resulted in an injury)?
Depends on the technique of cannulation and carefulness of postop exams
What makes you a good expert for this case?
I have 20 years of cardiac surgery experience and frequently use femoral cannulatikn
How often do you encounter cases similar to this one in your practice?
Femoral cannulation is common in my practice
Do you believe there might have been medical error?
This type of nerve injury and loss of motor function is not a common complication nor is it often even quoted as a rare complication of femoral cannulation. Injury to the femoral nerve and its cause will largely be related to how the femoral cannulation was performed (example percutaneously vs cutdown).
Do you believe there might have been causation (i.e. the medical error resulted in an injury)?
As I previously stated, this is very unusual and unexpected for this complication to occur. The mechanism is hard to explain and will depend on how cannulation was performed and how the femoral vessels were accessed (eg. percutaneously vs open).
What makes you a good expert for this case?
I have been an academic cardiac surgeon in practice for 14 years and am currently division chief at a public, academic institution. I am the director of minimally invasive cardiac surgery at my center and have been performing minimally invasive cardiac surgery for over 10 years including minimally invasive mitral valve surgery. I have performed peripheral femoral cannulation both open and percutaneously dozens of times.
How often do you encounter cases similar to this one in your practice?
I have been doing minimally invasive cardiac surgery and valve surgery including minimally invasive mitral valve surgery for over 10 years. I have never encountered this complication in my practice.
Do you believe there might have been medical error?
Nerve injury is a known complication of groin cannulation. Very large cannuas are inserted through the small groin space. These cannulas have to stay in place for several hours during heart surgery, often causing compression of the adjacent nerves. In addition, even after removal of the cannulas, blood clots can form and cause long term nerve compression. This is the reason nerve injury can occur even if the surgery is performed perfectly.
Do you believe there might have been causation (i.e. the medical error resulted in an injury)?
This kind of nerve injury is common when cannulas are inserted. If ultrasound was used during the insertion (or if an open approach was done), cannulation would have been done under direct visualization and there was a very low chance of insertion injury to adjacent nerves. The nerve injury is not the rsult of insertion but the unfortunate side effects of the large size of cannulas.
What makes you a good expert for this case?
I have been a cardiac surgeeon for over 20 years and have performed over 3,000 open heart surgeries like this one. I am familiar with the procedure and I am able to explain the technical nature of the case to the standard public.
How often do you encounter cases similar to this one in your practice?
I encounter mitral valve surgery cases about once a week
Do you believe there might have been medical error?
I would surmise that a medical error is possible, but the facts of the case don't all add up. SOme, but not all, of the clinical and nerve conduction study findings, as well as the timing of onset of clinical deficits, correspond to the timing of right femoral artery cannulation. Femoral nerve injury as a result of needle puncture, or some step in cannulation, is a known complication, albeit uncommon, complication of femoral cannulation (In a study of 9,585 femoral-approach cardiac catheterization procedures performed between 1988 and 1993, Kent et al. reported an incidence of femoral neuropathy of 0.2%. In this study, the incidence was 3.8 per 100,000, which may be an underestimate of the actual occurrence: not all patients were evaluated for signs and symptoms of FN.) The expected deficits of femoral nerve injury would be both sensory (medial thigh) and motor (hip flexion and knee flexion - quadriceps) and possibly thigh adduction. The femoral nerve does not supply the tibial and peroneal nerve as they originate as a branch of the sciatic nerve - so those findings are not consistent with femoral nerve injury. The femoral nerve may be injured by direct trauma, or indirectly as a result of a pseudoaneurysm or hematoma - one would want to rule this out and relieve it if identified.
Do you believe there might have been causation (i.e. the medical error resulted in an injury)?
Possibly, as some, but not all of the clinical findings are explainable by femoral nerve injury. See above. The quadricep findings may be explainable by femoral nerve injury, but not the peroneal or tibial nerve findings. Also, not clear why patient has not described sensory deficits as this is the most common complication from femoral nerve injury. Possibly, as some, but not all of the clinical findings are explainable by femoral nerve injury. See above. The quadricep findings may be explainable by femoral nerve injury, but not the peroneal or tibial nerve findings. Also, not clear why patient has not described sensory deficits as this is the most common complication from femoral nerve injury.
What makes you a good expert for this case?
18 years in clinical practice, over 1600 groin cannulations as part of TAVI team, board certified aortic surgeon and fellowship in peripheral vascular and endovascular surgery
How often do you encounter cases similar to this one in your practice?
Very uncommon complication. Possibly, as some, but not all of the clinical findings are explainable by femoral nerve injury. See above. The quadricep findings may be explainable by femoral nerve injury, but not the peroneal or tibial nerve findings. Also, not clear why patient has not described sensory deficits as this is the most common complication from femoral nerve injury.
Do you believe there might have been medical error?
Cannulation using the femoral artery and vein are commonplace for minimally invasive surgery. The absolute etiology of the nerve damage in this case can be multifactorial and may be difficult to prove. The cannulation itself rarely causes nerve damage. The work-up seems thorough but sounds as if they didn’t isolate the culprit event. Still, the etiology could be stroke, local nerve damage, or perhaps something not worked-up… for instance, has the patient ever had a herniated disk in his back? This may have led to weakness which might not have been noticed prior to surgery and became exacerbated by the cardiac surgery. Nothing presented here seems suspicious for medical negligence or an error in surgical technique.
Do you believe there might have been causation (i.e. the medical error resulted in an injury)?
There is no clear-cut link between the cannulation and the post-op weakness, as many possibilities can account for this condition. More likely than not, despite the MRI scan, stroke or a pre-existing condition may account for the weakness.
What makes you a good expert for this case?
This case does not seem meritorious.
How often do you encounter cases similar to this one in your practice?
I’ve never seen this from cannulation. That’s why a pre-existing condition or stroke seem more likely causes.
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