“Dark times lie ahead of us and there will be a time when we must choose between what is easy and what is right. -Albus Dumbledore” ― J.K. Rowling, Harry Potter and the Goblet of Fire
There is a subtle genius in the quote above. Note that the dichotomy is between what is right and what is easy, not between what is right or wrong or by extension, between what is good and what is bad. Had the dichotomy been between what is right and what is wrong, the quote could easily be dismissed, as it is highly unlikely that many would ever purposely choose wrong over right. The elements of that dichotomy are directly oppositional; they are mutually exclusive. This is not the case when the choice is between what is right and what is easy, because the opposition or mutually exclusive nature is not so clear and thus, not so readily dismissed. It takes at least a momentary pause to think how could doing what is easy be exclusive of doing what is right?
It would not be an overstatement to say that Deep Brain Stimulation (DBS) lead implantation surgery is complex and buffeted by many opposing interests. One of the best descriptions of DBS lead implantation is that it is “fussy” with many moving parts. Further, the need to be as sure as possible that the DBS lead is in the optimal location often works in opposition to minimizing surgical risk to the patient and minimizing the time, hence expense, of the surgery. The purpose of this writing is to help frame the questions.
I hope to make the argument that what is right is ensuring that the DBS lead is in the optimal location. How to define what is the optimal location may be a matter of debate, but it is not a debate that should take place in the operating room. Further, while it is important to minimize risk, this is not really the deciding issue in the operating room. Certainly, expense should not be an element as well.
The perspective taken to make the argument rests on the ethical considerations of autonomy and justice. With respect to autonomy, by giving consent, the patient or the patient’s representative sets the stage for decisions to be made in the operating room. The patient or the patient’s representative have decided what is the range of surgical risks allowed, given the expected benefit. Thus, if the surgeon operates within the range of surgical risks allowed by the consent of the patient or the patient’s representative, assuming this requires optimal lead location, is the driving factor. To be sure, the surgeon has the obligation to minimize the risk even within the range allowed by the consent of the patient or the patient’s representative; however, to reduce the chance of optimal DBS lead location, while remaining in the range of risk, would be to alter the bargain the patient or the patient’s representative agreed to, hence an injustice.
Certainly, the range of surgical risk acceptable to the patient or the patient’s representative cannot be explicit and detailed in a technical manner. However, it would be sophistry to argue that the patient or the patient’s representative cannot be given a general understanding that at the very least would provide some framework. For example, a patient may be of the position that the risk of an intracranial hemorrhage producing weakness may not outweigh the relief from the Parkinsonian tremor and may not want multiple microelectrode penetrations of the brain for mapping, as this would increase the risk of intracranial hemorrhage. The patient or the patient’s representative accepts that the probability for optimal relief of tremor is less. The patient or the patient’s representative may opt for DBS lead placement under MRI. It is an unintended consequence that the DBS lead implantation surgery would be easier. The converse may be true as well and by the consent process, the patient or the patient’s representative gives the surgeon license to preform multiple penetrations of the brain for microelectrode recordings to ensure the appropriate chance of benefit. Certainly, it would be easier to make fewer, perhaps insufficient, penetrations but this would be choosing what is easier rather than what is right.
The expense of the surgery is (should) not be the problem of the patient or the patient’s family, but rather the problem of the insurer and provider. To be sure, each patient does not exist in a vacuum and all of society bears the costs in one way or another. Thus, all have an obligation to reduce costs, but to do so outside the bargain struck in the process of obtaining informed consent would be an injustice.
The tricky part is defining what is the optimal location to ensure benefit. It would be great if there were a specific set of indicators that had very high positive and negative predictive values of clinically meaningful improvement. However, these do not exist and thus, some “stand-in” must be used. For example, in the case of targeting the subthalamic nucleus for DBS lead implantation using microelectrode recording, this author uses the criteria of: 1) at least 5 mm of sensori-motor driven neuronal activities; 2) no adverse effects with micro-stimulation; and 3) helpful but not mandatory, improvement with micro-stimulation. To be sure, these criteria have not been subjected to randomized controlled trials, and they likely never will be. The origin and rationale for these criteria are beyond the scope of this writing, but those interested can consult this author’s textbook (potential conflict of interest duly noted) Intraoperative Neurophysiological Monitoring for Deep Brain Stimulation: Principles, Practice and Cases, Oxford University Press, 2015.
With regards to targeting the globus pallidus interna, this author’s criteria for optimal location are: 1) the homuncular representation in sensori-motor region appropriate to the patient’s most significant disabilities; 2) at least 2-3 mm anterior to the posterior limb of the internal capsule (3-4 mm in the case of dystonia); 3) at least 2-3 mm from the optic tract (3-4 mm in the case of dystonia); 4) no adverse effects with micro-stimulation; and 5) helpful, but not necessary, improvement with micro-stimulation. With regards to targeting the ventral intermediate nucleus of the thalamus, this author’s criteria for optimal location are: 1) the homuncular representation in sensori-motor region appropriate to the patient’s most significant disabilities; 2) at least 2-3 mm anterior to the anterior boarder of the caudal portion of the ventral caudal thalamus; 3) no adverse effects with micro-stimulation; and 4) helpful, but not necessary, improvement with micro-stimulation.
The issue for this essay is not what are the criteria for the optimal location, but rather deciding that there are criteria, that these criteria define what is right. They should not be diluted or escaped, because they are not easy . Within the bounds of accepted risk as discussed above the obligation is to do what is right, not what is easy. For example, the criteria for an optimal location should not be sacrificed because it is easier to not do the additional penetration and microelectrode recording that might result in meeting the criteria.
The slippery slope arises when the question becomes is it “right enough”? Perhaps not all the criteria are met but the location still may be “right enough”. This is a dangerous move. If the criteria for “right enough” is appropriate, that criteria should be the criteria that is just “right”. To differentiae between “right” and “right enough” is to discount or diminish what is “right”. Allowing “right enough” is antithetical to the notion of “right,” if pursuing “right” does not take the risks outside the bounds described above.
In this author’s experience, the notion of “right enough” typically comes up when things are not easy and yet within the bounds of risk. The surgery may be taking longer than expected. There may be technical issues that, while not interfering with doing what is right, make it less easy. Certainly, “right enough” may be appropriate where attempting to do what is right takes the patient outside the previously agreed upon range of risks. Yet, in this author’s experience, fortunately, this is rarely the case.
The best way to avoid the slippery slope of “right enough” is to stipulate what “right” means before the DBS lead surgery and committing to that criteria as long as it is within the bounds of risk, as described above.