DISCUSSION
nausea, postoperative pain, headaches, anxiety, sleep disturbance, numbness, vomiting, migraine-type, pain, headache, Cranial Nerve, maxillary branch) sensory, postoperative headache, trauma
STERILE, VASODILATION, EXTRAVASATION, INFLAMMATION
Usually, prolonged hospital admissions following total endoscopic endonasal pituitary surgery result from headache and nausea +/- vomiting. The etiology of their postoperative headache is likely multifactorial, but one theory is that stimulation of the peripheral trigeminal (Cranial Nerve number V) fibers in V1 (ophthalmic branch) and V2 (maxillary branch) sensory distribution of the face by the surgical endoscope and surgical trauma may lead to extravasation and release of inflammatory mediators (Substance P (SP), calcitonin gene-related peptide (CGRP), and Vasoactive Intestinal Peptides (VIPs)) from the local area via the trigemino-vascular system. This “sterile neurogenic peri-vascular inflammation” can ultimately cause meningeal blood vessel vasodilation, increased cerebral blood flow, and migraine-type post-op headaches [These study results showed that the addition of supra-orbital and infra-orbital sensory trigeminal nerve blocks intra-operatively to general anesthesia during transsphenoidal, total endo-nasal pituitary surgery does not appear to reduce postoperative headache and thus, 6-hour post-op morphine PCA consumption as compared to patients receiving only general anesthesia. In fact, the placebo group had less postoperative pain and morphine use, along with a shorter median PACU stay. As the standard deviations in both groups were varied, this effect was not clinically significant. Possible explanations for this unexpected pain and morphine consumption post-op response in the block group may include:(1) It may be more difficult to accurately execute the supra-orbital V1 and infra-orbital nerve V2 blocks under general anesthesia than expected. The terminal sensory nerve anatomy of patients may vary, and so the block, placed using landmarks, may not actually capture all branches of the trigeminal nerves V1 and V2, which may then eventually trigger the trigeminovascular effects, leading to post-op headaches. As the patients were under general anesthesia, the presence/absence and extent of numbness were not evaluated prior to surgery. Post-op evaluation of this would have led to unblinding the patient and the data collection nurse, so this was not performed. Thus, the two groups showed similar postoperative pain exposure data and morphine use.(2) It is possible that the administration of normal saline solution used in the placebo group may have some analgesic properties, resulting in similar pain exposure and 6-hour post-op morphine use data.(3) Most surprisingly/unexpectedly, there was a tendency for slightly paradoxically increased pain exposure, morphine usage, and median time of PACU stay in the block group. One possible explanation for this could be the influence of another mechanism in addition to the sensitization of the trigeminal ganglion in the production of post-op headaches. The sphenopalatine ganglion (SPG), a primarily parasympathetic ganglion, located in the pterygopalatine fossa (posterior to the middle nasal turbinate), is known to communicate directly with the trigeminal ganglion via several branches of the infra-orbital or maxillary V2 nerve (Fig. (4) invasive and riskier [(5) Perhaps future studies should focus on randomized, controlled data using both the trigeminalnerve blocks combined with the sphenopalatine ganglion block as a multimodal regional adjunct to general anesthesia for transsphenoidal pituitary resection.(6) As there appeared to be little difference in pain exposure and morphine consumption post-op, no significant difference was reported in post-op nausea over time between the block and placebo groups.(7) In addition to the pain complexity described, it is possible that patients may have had variable amounts of preoperative anxiety and associated sleep disturbance, which may variably amplify/ affect their perceived postoperative surgical pain experience. All patients received midazolam 1-2 mg IV pre-operatively as a premedication prior to surgery based on their subjective reported level of preoperative anxiety. A total of 81% of placebo (P) patients received 2 mg of midazolam IV, and 78% of block (B) patients received 2 mg of midazolam IV. We recorded baseline preoperative pain data prior to surgery, which was considered in our statistical calculations related to pain exposure. We did not gather data on sleep disturbance and anxiety.The postoperative time to discharge and time to last dose of narcotics from the start of surgery for the block and placebo groups did not have statistically significant differences. Considering pain on discharge, the placebo group had less pain, although the final median pain scores of 1/10 for placebo and 2/10 for block did not seem to have clinical significance. However, examining the individual pain scores, the block group was found to have greater pain data, showing some patients with significant pain on discharge.