Pain Control After Orbital Implant Surgery

I read with interest the recent article by Fezza et al.¹ I congratulate the authors on their description of a new method for postoperative pain relief after orbital implant surgery (using a bupivacaine hydrochloride infusion into the orbit through an epidural catheter). The authors stated in their conclusion that it was an effective means to achieve postoperative pain control, simple, and well tolerated.

I agree with the author's that "placement of orbital implants can be associated with severe postoperative pain." The key word is can. Not all patients experience severe pain, and the problem is knowing who is and who is not going to have the severe pain. The authors report that 51.2% of patients reported no postoperative pain with their orbital catheter pain relief technique, 37.0% reported some pain ranging from mild to moderate, and 11.8% reported severe pain. It would have been valuable to know what the percentages were in a control group (without the intraorbital catheter technique), which is the major problem I find with this article. We really do not know the percentage of people with no postoperative pain, some pain, or severe pain when the catheter system was not used. I was surprised to see that 11.8% still had severe pain and 37.8% had some pain ranging from mild to moderate (despite the orbital catheter delivery of bupivacaine). In my own experience of more than 300 hydroxyapatite implants (evisceration, enucleation, and secondary implants), I do not believe that more than 10% of patients have severe pain (without the use of the intraorbital catheter technique they describe). Similarly, the 37.8% incidence of mild to moderate pain is about what I have noticed in a similar group of patients (without the intravenous catheter they describe). I routinely prescribe acetaminophen with codeine and occasionally an intravenous narcotic (such as meperidine hydrochloride) during their day or overnight hospital stay and acetaminophen with codeine for the next week (as needed) while at home. I find this routine quite adequate.

The patients in the study were also given the option of receiving a bolus of extra bupivacaine, but we do not know how often this was done or whether pain was relieved with a bolus. Similarly we do not know how many patients used their prescription for oxycodeine in case they had breakthrough pain and whether the oxycodeine worked when it was administered. Thus, I must question how beneficial this technique is and whether it should be used on all patients undergoing implant surgery.

The other problems I find with the technique is that daily visits by a nurse were required to check the functioning of the pump. The cost of these visits in addition to the added expenses of the medication (bupivacaine), infusion pump, intravenous catheter, and tubing, for a technique that still does not offer complete pain relief in 48.8% of patients (37.0% still had mild to moderate pain, and 11.8% still had severe pain), again raises the question in my mind about how cost-effective it is.

The authors state that patients receiving a secondary orbital implant had the most severe pain and suggest that these patients are the best candidates for an orbital bupivacaine infusion. I have found that a number of evisceration patients, particularly those who have posterior sclerotomies (to allow insertion of a larger implant), are most likely to have severe pain. I therefore find it hard to predict who is going to have pain and who is not. If we could make this prediction, I would be interested in trying this new and interesting technique. Unfortunately, we cannot.

Although the authors document the safety of their technique in 119 patients, the potential for complications with bupivacaine does exist, is nicely documented in the article (seizures, respiratory depression, arrhythmias, cardiovascular collapse, retinal artery or vein obstruction, retrobulbar hemorrhage, brainstem anesthesia, and apnea), and should not be forgotten. I am surprised the patients consented to the use of this retrobulbar medication with the list of potential problems described in the article.

Lastly, in the final paragraph, the authors state that the technique "has made a major clinical difference, leaving most patients essentially pain free." The actual percentages however were 51.2%, no postoperative pain; 37.0%, some pain (mild to moderate); and 11.8%, severe pain. Does 51.2% constitute "most" patients? Although their technique likely does give some pain relief, based on their study results, I find it difficult to say how beneficial it really is. Until I have something with which to compare their results, I am going to continue administering intravenous meperidine while my patients are at the hospital (day or overnight-stay patient) and acetaminophen with codeine orally every 4 to 6 hours as needed for the next week.