10/2022: 75-year-old male patient underwent a left carotid endarterectomy with patch angioplasty. Records are somewhat contradictory regarding the degree of stenosis: 1 note says it was greater than 70% on Duplex, but a 7/15/2022 CTA described only 50% stenosis, and a treating cardiologist noted later that "preprocedure CT scan only demonstrated moderate left internal carotid stenosis."
During the procedure, which was done by a vascular surgery fellow, the hypoglossal nerve was injured and possibly transected. The original operative note does not mention it, but an addendum by the attending surgeon states: "Left hypoglossal nerve required suture repair and the tongue is deviated post op as expected."
The patient has had ongoing complications with dysphagia and dysarthria.
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Do you believe there might have been medical error?
All vascular surgeons that are trained and board certified are taught to identify and preserve the hypoglossal nerve. That being said it does happen, anywhere from 2-4% in the literature. It appears that if they tried to suture it together, then it was completely transected and that tends not to work. The more concerning issue is why was a fellow trainee unsupervised performing high risk cerebrovascular procedure. In my academic practice, we are present for these and most all cases from start to finish.
Do you believe there might have been causation (i.e. the medical error resulted in an injury)?
The patient is expected to have dysphagia and dysarthria after transection of the hypoglossal nerve. Those symptoms are directly related to hypoglossal nerve injury.
What makes you a good expert for this case?
I perform open CEA and TCAR on a routine basis. I also am RPVI certified to evaluate the duplex and assess the degree of stenosis if patient truly needed an operation. I have also authored papers in vascular peer reviewed journals regarding cerebrovascular disease.
How often do you encounter cases similar to this one in your practice?
We do approximately 20-30 open CEA operations a year in our practice. With the introduction of TCAR the numbers have come down some to 20-30 and prior we probably did more. This is a fairly common case and standard on the oral and written boards for all vascular trainees.
Do you believe there might have been medical error?
Injury to the hypoglossal nerve is a known complication in the setting of carotid endarterectomy and occurs in approximately 4.4 to 17.5% (Perler, 2023). Most of these injuries are based on traction and/or manipulation of the nerve and exceedingly rarely due to transaction of it. The former injury presentation usually self-limited and resolves over a several months. The later injury pattern indicates a junior and/or in-experienced surgeon undertaking the procedure. The indications for the carotid endarterectomy are dependent if the patient has symptoms originally. General speaking, neurological symptoms with a 70% stenosis (on duplex) is a threshold for an operation. That said the CT scan as described in this case might indicates 50% stenosis. Perler B. Chapter 93: Carotid Endarterectomy. In Rutherford's Vascular Surgery and Endovascular Therapy, 2-Volume Set, (2023). Chapter 93, 1220-1240.e7.
Do you believe there might have been causation (i.e. the medical error resulted in an injury)?
Key aspects as it relates to causation and general liability in the case include: a. Who was actually undertaking the procedure? b. If a learner was undertaking the procedure (that is the vascular surgery fellow as stated in the case) did she/he/they have appropriate oversight? c. How was the injury identified, mainly did the injury occur while a junior surgeon was undertaking the case and then identified by the more senior supervision surgeon? d. What was the clinical presentation of the patient? e. Based on number 4, what was the degree of stenosis seen on duplex and/or fix imaging (the latter of which is usually considered more accurate)?
What makes you a good expert for this case?
I undertake and/or oversee several of these types of operative cases during the year. I also follow several hundred patients with this disease state in pre-operative and post-operatively periods with carotid duplex and or CT imaging. I have also published in the peer review literature regarding this patient population and potential suitability based on frailty.
How often do you encounter cases similar to this one in your practice?
As stated above, traction injury does occur during this type of operation, and I have seen it in my own patients and that of my partners. Our rate of complication is less than the stated upwards limits of 20%. I have seen transection only once during my training.
Do you believe there might have been medical error?
The hypoglossal nerve takes a variable course relative to the carotid bifurcation. While the location is not typically dictated, those with an obvious HG nerve in the operative field that requires gentle retraction may be mentioned. Given that this was a trainee and they failed to dictate this, the attending MD did, in fact include this for the sake of clarity and integrity to the case requirements. CN injury is a known complication of CEA. This is not intentional maleficence.
Do you believe there might have been causation (i.e. the medical error resulted in an injury)?
Obviously, the recognized injury was treated , but the expected neuropraxia was acknowledged.
What makes you a good expert for this case?
I am a board certified senior vascular surgeon who performs dozens of these procedures a year.
How often do you encounter cases similar to this one in your practice?
I have seen three episodes of traction injury, and have seen actually transection by another colleague only once in the last 15 years.
Do you believe there might have been medical error?
Probably high bifurcation requiring mobilising and dissection of the nerve that may cause injury
Do you believe there might have been causation (i.e. the medical error resulted in an injury)?
Mobilisation because of high bifurcation
What makes you a good expert for this case?
I am a vascular surgeon with more than 500 carotid endarterectomy cases
How often do you encounter cases similar to this one in your practice?
Temporary injury from traction 5% Complete injury < 1%
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