Palatal Block
Indications: Cleft palate repair, though individual blocks can be used for site-specific teeth extraction.
Innervation of the palate: The sensory innervation of the palate is provided by branches of the maxillary division of the trigeminal nerve which synapse in the pterygopalatine ganglion:
Nasopalatine Nerve supplies the palate anterior to the incisive foramen
Greater Palatine Nerve supplies most of the palate, supplying the palate anterior to the greater palatine foramina
Lesser Palatine Nerve supplies the palate posterior to the greater palatine foramina
Complications:
General risks: Intravascular injection; block failure
Risks based on (adult literature) advancing the needle 4cm into greater palatine canal: Diplopia, strabismus and ptosis; Nasal bleeding/penetration of nasopharynx;Injury to neural tissue; Temporary blindness; Loss of consciousness; Retrobulbar hemorrhage
Technique:
Nasopalatine Nerve
The nasopalatine nerve exits the nasopalatine foramen, which is located directly midline and posterior to the central incisors. The nasopalatine nerve is typically blocked by a single injection at the level of the nasopalatine foramen. Some sources also refer to the nasopalatine foramen as the incisive foramen.
This block is considered very painful, so it should be done after induction.
Using a 25g needle, inject at a depth < 1cm very slowly just lateral to the incisive papilla (small pear or oval shaped mucosal prominence situated at the midline of the palate, posterior to the palatal surface of the central incisors on the palate at the midline). Typically, a single injection is sufficient.
In cases of complete cleft lip and cleft palate in which a nasopalatine foramen does not exist, local solution can be injected submucosally on both sides of each incisor (as depicted by x’s in Fig. 3).
Greater Palatine Nerve
The greater palatine nerve exits the greater palatine foramen (GPF), the distal end point of the greater palatine canal. While some sources suggest inserting the needle directly into the canal and advancing it <1 cm towards the pterygopalatine ganglion, others suggest injecting strictly submucosally, decidedly NOT into the canal. There are reports of injury to additional canal contents, as well as unintentional blocking of other branches of V₂ and V₃ leading to ptosis, diplopia, strabismus, temporary blindness, retrobulbar hemorrhage, and unconsciousness from intracranial injection.
Place a cotton-tipped applicator just medial to first molar and advance posteriorly until the GPF is identified as a small depression. The location of the canal varies, but 87% of the time it will be situated medial somewhere between the 2nd or 3rd molar (Fig. 4).
After identification, advance a 25g needle <1 cm submucosally, and after (-) aspiration, inject.
Lesser Palatine Nerve
The lesser palatine nerve also travels within the greater palatine canal, but exits through the lesser palatine foramen, typically found just lateral and posterior to the greater palatine foramen (Fig. 2).
Lesser palatine nerve (LPN) is blocked at the lesser palatine foramen (LPF), which is just posterior and lateral to GPF at a depth of < 1cm
Figure 1
Figure 2
Figure 3
Figure 4
In 2010, Jonnavithula et al evaluated the efficacy of the palatal block in pediatric cleft palate repair. They randomized children into three groups: control (no block), block with saline, or a block with 0.25% bupivacaine. They found the palatal block conferred no anesthetic-sparing effect but did significantly lower pain scores. Not surprisingly, parental satisfaction was poor in the control group. The time to first demand dose of analgesic was 6 hours for the control group, while interestingly 18 hours for palatal blocks with bupivacaine AND with saline. The authors’ proposed mechanism of analgesia produced by saline was mechanical distension pressure over the nerve sheath rather than actual blockade. Before any of you switch over to saline, keep in mind the “analgesic” effect of saline block was not consistent.
In 2016, Botros et al evaluated the efficacy of landmark suprazygomatic maxillary nerve blocks vs only one component of the palatal block—greater palatine nerve—and found bilateral greater palatine blocks were actually superior for intraoperative analgesia! However, this might be explained by the fact that the suprazygomatic block was performed as a blind technique. I think the take home point is that your cleft palate kids will benefit from either technique.
In a later study, Echaniz et al also evaluated the efficacy of proximal vs distal maxillary nerve blocks in cleft repairs (lip and/or palate). For proximal, they performed bilateral suprazygomatic via landmark technique, while for distal they performed (bilateral infraorbital and palatal blocks). They found no difference in post-op pain scores, post-op opioid use, or post-op complications, though the proximal group did have a significant reduction in intraoperative nalbuphine, as well as lower intraoperative fentanyl requirements.
In 2018, Elyazed et al brought ultrasound into the equation. They randomized patients into 3 groups: control (no block), bilateral ultrasound-guided suprazygomatic maxillary (s) vs bilateral palatal nerve blocks (p). They found that both block groups were superior to control, but that the (s) group had much greater pain relief and decreased rescue analgesics compared to the (p) group. The (s) group was also much quicker to feed.
In a recently published review article, Oberhofer et al looked at the use of nerve blocks in palatal repair. Due to study heterogeneity and small study sizes, they make no recommendations of one technique over another, but do come to the conclusion that intraoperative nerve blocks have been shown to be incredibly effective in reducing postoperative pain in children undergoing palatoplasty, minimizing both opioid consumption and recovery time. And by adding 1mcg/kg of dexmedetomidine, Obayah et al showed that it increased greater palatine nerve block duration by 50%.
While the literature does seem to suggest that ultrasound-guided suprazygomatic maxillary nerve blocks may be the superior choice, there is still convincing evidence that palatal blocks are also very efficacious compared to controls—even with just saline!
McKinney, K.A., Stadler, M.E., Wong, Y.T., Shah, R.N., Rose, A.S., Zdanski, C.J., Ebert Jr, C.S., Wheless, S.A., Senior, B.A., Drake, A.F. and Zanation, A.M., 2010. Transpalatal greater palatine canal injection: radioanatomic analysis of where to bend the needle for pediatric sinus surgery. American journal of rhinology & allergy, 24(5), pp.385-388.
Sved, A.M., Wong, J.D., Donkor, P., Horan, J., Rix, L., Curtin, J. and Vickers, R., 1992. Complications associated with maxillary nerve block anaesthesia via the greater palatine canal. Australian dental journal, 37(5), pp.340-345.
Echaniz, G., De Miguel, M., Merritt, G., Sierra, P., Bora, P., Borah, N., Ciarallo, C., de Nadal, M., Ing, R.J. and Bosenberg, A., 2019. Bilateral suprazygomatic maxillary nerve blocks vs. infraorbital and palatine nerve blocks in cleft lip and palate repair: A double-blind, randomised study. European Journal of Anaesthesiology| EJA, 36(1), pp.40-47.
Jonnavithula, N., Durga, P., Madduri, V., Ramachandran, G., Nuvvula, R., Srikanth, R. and Damalcheruvu, M.R., 2010. Efficacy of palatal block for analgesia following palatoplasty in children with cleft palate. Pediatric Anesthesia, 20(8), pp.727-733.
Suresh, S. and Voronov, P., 2012. Head and neck blocks in infants, children, and adolescents. Pediatric Anesthesia, 22(1), pp.81-87.
Iwanaga, J. and Tubbs, R.S. eds., 2019. Anatomical variations in clinical dentistry. Springer.
Sved, A.M., Wong, J.D., Donkor, P., Horan, J., Rix, L., Curtin, J. and Vickers, R., 1992. Complications associated with maxillary nerve block anaesthesia via the greater palatine canal. Australian dental journal, 37(5), pp.340-345.
Loughran, C.M., Raisis, A.L., Haitjema, G. and Chester, Z., 2016. Unilateral retrobulbar hematoma following maxillary nerve block in a dog. Journal of Veterinary Emergency and Critical Care, 26(6), pp.815-818.
Aoun, G., Zaarour, I., Sokhn, S. and Nasseh, I., 2015. Maxillary nerve block via the greater palatine canal: An old technique revisited. Journal of International Society of Preventive & Community Dentistry, 5(5), p.359.
Elyazed, M.M.A. and Mostafa, S.F., 2018. Bilateral suprazygomatic maxillary nerve block versus palatal block for cleft palate repair in children: a randomized controlled trial. Egyptian Journal of Anaesthesia, 34(3), pp.83-88.
Botros, M., Ezzat, A., Girgis, K., El-Sonbaty, M. and Selim, M., 2016. Comparative study of bilateral greater palatine nerve block and bilateral suprazygomatic maxillary nerve block for intraoperative analgesia in children undergoing palatoplasty. Med J Cairo Univ, 84, pp.257-61.
Oberhofer, H.M., Breslin, N., Heindel, H. and Ching, J., 2021. Analgesic Efficacy of Intraoperative Nerve Blocks for Primary Palatoplasty. Journal of Craniofacial Surgery, 32(2), pp.594-596.
Obayah, G.M., Refaie, A., Aboushanab, O., Ibraheem, N. and Abdelazees, M., 2010. Addition of dexmedetomidine to bupivacaine for greater palatine nerve block prolongs postoperative analgesia after cleft palate repair. European Journal of Anaesthesiology| EJA, 27(3), pp.280-284.