When I first started Botulinum injections I just just injecting intradermally the areas where they felt the pain. Then it became clear the trigger zone needed special treatment and subcut was more done. I used to have a researcher repeatedly email me for any updates on TN injections. Now there are some – Injecting the roots (origins) of the affected trigeminal nerve (II and III anyway), and injecting the muscle in the trigger zone.
Börü, Ülkü Türk, et al.
Botulinum toxin in the treatment of trigeminal neuralgia: 6-Month follow-up.
Medicine 96.39 (2017).
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5626289/pdf/medi-96-e8133.pdf
- 27 patients – 78% female; 55 average age though varied from 27-77 The mean duration
- Had TN average of 4.2 ± 2.6 years
- 10/17 had two roots affected
-
used a dental needle of 0.40 50mm for injection
- put in 50 u botulilnum in each nerve root -Botox dilute 100 units in 2 mls saline
- sitting with head on headrest; moth open slightly
I have several pics of that as authors one for maxillary is not detailed enough:
For Maxillary:
- they went ABOVE zygomatic arch, midway between the external ear and the orbital rim. though other 2 pics went below arch and angled up and foreward.
- “needle was pointed toward the zygomatic bone on the other side
of the skull (forming obtuse angles to the front and below) at a
depth of 50mm)
Couple other pic I have of Maxillary Nerve root injection went below zygomatic arch and just angled up and forward:
Mandubular:
- in mandibular notch below the middle of the zygomatic arch.
- point more directly backward
- “After striking the pterygoid process, the needle was withdrawn slightly and rotated craniodorsally (up and front I presume) about 5 to 10mm and the solution was administered around the trigeminal ganglion”
Need for retreatment:
- 55% had recurrence at 54.7± 30.5 and were retreated ( if retreatment was that early, then Xeomin botulilnum, being less allergenic, would have been a better choice)
- 26% cases needed a third injection at 88 days
results are mouth watering:
- attack frequency was 217.7/day to start; 71.5/day 1st week, 54.8 in 2nd month, 55/day in 6th month
- p value was recorded as p= 0.000
- “This technique showed that pain severity decreased by almost 90% …at 6 months”
Side effects: “1 patient experienced short-term facial weakness on the injection side, this side effect disappeared within 2 months. Masseter weakness on the injection side was
observed in 2 patients, and after the third injection, remained mild and permanent.”
Another approach:
Wu, Chuanjie, et al.
A new target for the treatment of trigeminal neuralgia with botulinum toxin type A. Neurological Sciences (2017): 1-4.
https://link.springer.com/article/10.1007/s10072-017-3171-7
- make comment that “30% of TN cases are refractory to subcutaneous BoNT-A treatment.”
- case where injected 50 u BoNT-A /1 ml ( into painful gingival area without effect but the redid later into masseter muscle – protocol was “50 U BoNT-A each, at three separate points of the right (afflicted) side masseter muscle.” – so total 150 u which was repeated 5 months later
- “In the clinic, we have observed poor results using subcutaneous injection for TN when pain was confined to the gingival area, and this case was not an exception. Changing to an intramuscular (intra-masseter) protocol achieved dramatically
greater therapeutic efficacy.” - they strongly recommend “Intramuscular (masseter) injection of BoNT-A may improve its therapeutic effect, especially for patients in whom TN pain is confined to the gingival area.”
Comment – looks like there are now 3 targets: trigeminal nerve roots, sensitized trigger zone, and masseter muscle. I will hit trigger zone and nerve roots and masseter with gingival triggers. I would stick to Xeomen as frequency of injections is more frequent. a depth 50 mm is substantial.