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ORIGINAL ARTICLE

Anatomic and Anaesthetic Considerations of Greater Palatine Nerve Block in Indian Population

Nidhi Sharma, Rohit Varshney1, Sudhakar Ray Departments of Anatomy, 1Anaesthesia, Teerthankar Mahaveer Medical College, Moradabad, Uttar Pradesh, India Correspondence: Dr. Rohit Varshney, Assistant Professor, Department of Anaesthesia, Teerthankar Mahaveer Medical College, Delhi Road, Moradabad, Uttar Pradesh - 244 001, India. E-mail: [email protected]

ABSTRACT

Background: Greater palatine nerve block holds its importance for anaesthesia and analgesia in different maxillofacial surgical procedures. Accuracy in localization of greater palatine foramen is required for its successful implication in regional block, although racial variations exist in various population groups. Aims: To study the morphometry of greater palatine foramen and its location with nearby anatomical landmarks in Indian population. Material and Methods: A total of one hundred dry skulls (60 males and 40 females) were collected and observed for the study. Various parameters were noted from greater palatine foramen on both sides, together with its location with respect to maxillary molar tooth. Along with that the angle between midline maxillary suture and Incisive foramen- Greater palatine foramen is measured. Results: 198 sides were measured and the most common location of greater palatine foramen was found to be medial to third molar tooth (71.21%). The mean distance from greater palatine foramen to midline maxillary suture on right and left sides were 14.82 ± 1.34 mm and 14.79 ± 1.57 mm, statistically insignifi cant. The angle between midline maxillary suture and incisive foramen-greater palatine foramen was 20.81° ± 2.47°on right side and 20.58° ± 2.69°on left side.The direction of the opening of greater palatine canal onto the hard palate was observed to be antero-medial in 60.10% of cases. Conclusions: Our study reveals the importance of usage of various anatomical parameters for precise location of greater palatine foramen, establishment of specifi c measurements in each population group and thereby applying such measurements for successful greater palatine nerve block.

Key words: Greater palatine foramen, greater palatine nerve block, morphometry

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Access this article online INTRODUCTION Quick Response Code: Website: The greater palatine nerve is a branch of maxillary nerve, www.sjmms.net emerging from greater palatine foramen (GPF) and supplying the mucous membrane of hard palate, postero- DOI: 10.4103/1658-631X.142548 inferior part of lateral wall of nose and medial wall of maxillary sinus.

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Sharma, et al.: Morphometry of greater palatine nerve block

The greater palatine nerve block is commonly used for local 4. Distance from the center of the GPF to the posterior anaesthesia in different maxillofacial and dental procedures.[1] border of the incisive foramen (IF); Two extensively used techniques for intraoral greater palatine 5. Direction of opening of the GPF into the oral cavity; nerve block had been described in literature (high tuberosity/ 6. Angle between the MMS and line joining the IF with greater palatine canal approach). Considering the prospects GPF. of safety and ease of applicability greater palatine approach is more commonly practiced.[2] The measurements related to GPF were taken with double tipped compass and then transferred to verniercalipers The greater palatine nerve block is commonly employed (least count 0.01 mm) to measure the distances. The for anaesthetising hard palatal tissue distal to the canines dimensions were taken three times by the same person and medial to midline. It is a more suitable technique and mean was taken, thus increasing the accuracy of for providing analgesia in patients undergoing palatal the data.The direction of the opening of GPF into the surgeries as compared to opioids which are associated oral cavity was determined with the help of 25 G spinal [3] with various side effects. However, diffi culty in exact needle. All measurements were done bilaterally and localization of GPF leads to inability in obtaining directly on the dry skulls. The angle between the MMS adequate anaesthesia and analgesia.[4] and the line from the IF and the GPF were measured and calculated on digital photographs using the Vista Metrix Extensive medline search revealed different landmarks for the specifi c location of GPF. Hamilton[5] described its software (Skill Crest, Version 1.38, 2012). location near the posterior border of hard palate medial to Statistical Analysis: Mean ± standard deviation [mean posterior alveolus, Ferreria[6] depicted its position in the ± SD], median and range were calculated. Student’s hard palate at the level of the dihedral angle (formed by t-test was used for paired and independent samples. the horizontal lamina of the palatine bone and the inner Data analysis was done by using Statistical Package for surface of the maxillary alveolar process) and Rizzolo and Madeira[7] advocated its presence at the posterolateral Social Sciences (SPSS) version 19 and P-value < 0.05 angle of the palatine bone, next to the last molar tooth. was considered statistically signifi cant.

Moreover, the 2nd molar tooth is an unstable reference RESULTS point of GPF among different races and in conditions like periodontitis.[8-10] The total number skulls examined was: 100 [198 sides] Limited literature availability for localization of were males and 40 were females 60 appropriate position of GPF in Indian maxilla together The number of sides not examined due to destruction: with marked racial variation raises the idea behind the Right-0, Left-2 aim of our study to evaluate the location and direction So the total number of slides examined was 198. of the opening of GPF into the oral cavity in dry adult Indian skulls. MATERIALS AND METHODS

A total of one hundred dry skulls (60 males and 40 females) collected from medical and dental colleges of Teerthanke Mahaveer University, India, were used for the study. We excluded all child skulls and the skulls with damaged hard palate/greater palatine canal.

The following parameters were measured [Figure1]: 1. Location of the GPF in relation to maxillary molar tooth; 2. The center of the GPF to the midline maxillary suture (MMS); Figure 1: Hard palate. IF – Incisive foramen; GPF – Greater palatine foramen; MMS – Midline maxillary suture; PBHD – Posterior border of 3. The center of the GPF to the posterior border of hard palate; M2 – Maxillary second molar; M3 – Maxillary third molar; hard palate (PBHP); A – Angle between the MMS and the line from the IF and the GPF

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Sharma, et al.: Morphometry of greater palatine nerve block

Greater palatine foramen was observed in all the studied DISCUSSION skulls. In our study, 95.96% of GPF were located medially and Most common location of GPF was found to be in line antero-medially to third maxillary molar tooth. Ajmani with third molar tooth with the incidence of 71.21% et al,[8] Saralaya and Nayak[10] and Sujatha et al.,[11] followed by the position between second and third molar observed the location of GPF in Indian skulls adjacent tooth in 49% of skulls. However the presence of GPF to third and second-third maxillary molar tooth in 97.14, behind the third molar tooth in 8% skulls was the rarest 98.80 and89.10% cases, respectively. Similar locations location. No foramen was found opposite to second of GPF were encountered in the skulls of most of the molar tooth [Table 1]. cases by different investigators among various ethnic groups (Nigerian, Brazilian, Chinese, Greek, Iraq and The dimensions of GPF and its linear relationship Kenyan).[8,9,12-15] In Brazilian skulls,[13] GPF was located with surrounding anatomical landmarks on skull distal to third molar in 38.94% cases while we observed were summarized in Table 2. The mean distance from it in only 4.04% of cases. Location of GPF at the lingual GPF to MMS was 14.82 ±1.34 mm on right side and side of second molar was not found in any of our case 14.79 ± 1.57 mm on left side. The minimum distance but Ajmani et al.,[8] observed the same in 17% of Nigerian from GPF to MMS recorded was 13.12 mm and skulls. The above data from different population groups maximum was 15.51 mm. The mean distances between reveal that wide variability was seen for accurate location GPF-IF on right and left sides (37.74 ± 2.39 and of GPF. The importance of accurate localization of GPF 37.89 ± 2.83) mm and GPF-PBHP on right and left not only curtails down the possibilities of failed nerve sides (4.39 ± 1.73 and 4.53 ± 1.23) mm. However, no blocks but also decreases the number of pricks which statistical signifi cance was observed among any of the adds up suffering to the patient. above mentioned dimensions [Table 2]. Chrcanovic et al.,[13] observed the distance between GPF- The angle between MMS and IF-GPF was statistically MMS as 14.68 ± 1.56 mm and 14.44 ± 1.43 mm on the insignifi cant between both sides (20.81° ± 2.47°on right right and left sides respectively. In Indian skulls, Ajmani side and 20.58° ± 2.69°on left side) with the maximum et al.,[8] observed the distance of 14.7 and 14.6 mm on value of 22.03° and minimum value of 18.73° [Table 2]. the right and left sides and Saralaya and Nayak[10] found Anteromedial and anterior direction of the opening of the same dimension as 14.7 mm on both sides. Jafar and [9] greater palatine canal onto the hard palate was observed Hamadah observed the distance as 15.7 mm in Iraqian [16] in 60.10% and 31.81% of cases. Vertical opening of skulls while in case of Thais the mean dimension goes GPFin oral cavity was not found in any of the skulls up to 16.2 mms. Although we also observed wide variations examined [Table 3]. in the distance between GPF-MMS (13.12-15.51) mm but the mean distance on right and left side as 14.82 ± 1.34 mm and 14.79 ± 1.57 mm, respectively (P = 0.89) which Table 1: Location of greater palatine foramen along was less than other ethnic populations. The fl uctuating the maxillary tooth dimensions among different inhabitants could be attributed Location of Greater Right n (%) Left n (%) Total n (%) palatine foramen due to embryological factors of variable sutural growth Opposite to 2nd molar 0 (0) 0 (0) 0 (0) occurring between the maxilla and palatine bone.[13] Between 2nd and 3rd molar 25 (25) 24 (24.49) 49 (24.75) Opposite to 3rd molar 72 (72) 69 (70.40) 141 (71.21) The distance between GPF-PBHP holds its importance Behind 3rd molar 3 (3) 5 (5.10) 8 (4.04) for successful localization of GPF and preventing

Table 2: Distances from GPF to MMS/IF/PBHP and angle between the MMS and the line from the IF and GPF Dimensions Mean ± SD (mm) P value Median (mm) Range (mm) Right Left Right Left Right Left GPF-MMS 14.82±1.34 14.79±1.57 0.89 14.81 14.77 13.35-15.51 13.12-15.37 GPF-IF 37.74±2.39 37.89±2.83 0.68 38.81 39.01 36.69-40.86 35.67-42.12 GPF-PBHP 4.39±1.73 4.53±1.23 0.51 4.41 4.48 2.79-7.78 2.83-8.10 Angle between MMS and IF-GPF (in degree) 20.81°±2.47° 20.58°±2.69° 0.53 20.65° 20.23° 18.87°-21.25° 18.73°-22.03° GPF: Greater palatine foramen; MMS: Midline maxillary suture; IF: Incisive fossa; PBHP: Posterior border of hard palate

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Table 3: Direction of greater palatine foramen as our study was also observed by other investigators Direction of Greater Right n(%) Left n(%) Total n(%) in Indian skulls.[8,10,17] However, in case of Brazilian[13] palatine foramen and Chinese[15] skulls the anterior direction of opening Anterior 34 (34) 29 (29.59) 63 (31.81) of greater palatine canal is more commonly encountered. Antero lateral 8 (8) 8 (8.16) 16 (8.09) The direction of opening of greater palatine canal helps Antero medial 58 (58) 61 (62.24) 119 (60.10) Vertical 0 (0) 0 (0) 0 (0) in proper introduction of the needle into the foramen and gives an idea for the path to be traced up into the greater palatine canal. The variation in different ethnic accidental injury to nearby lesser palatine nerves and soft populations leads us to think a possible cause behind the palate. Moreover, this dimension also helps in localization diffi culty encountered during admitting the needle into of GPF in those cases where third molar tooth failed to the GPF. erupt or damaged due to any reason. In our study, the mean distance between GPF-PBHP on right and left The present study provides valuable information for the sides was 4.39 ± 1.73 mm and 4.53 ± 1.23 mm (P = location of GPF with respect to the surrounding anatomical 0.51), respectively, ranging from 2.79-8.10 mm. Wide landmarks in adult Indian skulls. These linear dimensions variations were observed in the distance between GPF- will prove to be helpful on living subjects in anaesthetic and PBHP among different sub-groups with both greater[9,14] surgical procedures and thereby preventing the dreadful and smaller dimensions[8,15-18] compared to our study, complications. Our fi ndings also emphasize on the ethnic again justifying the racial possibility behind them. variations in the occurrence of GPF as supported by other studies. Similar kind of work was done in the past by other Chrcanovic et al.,[13] found the mean angle in Brazilian Indian authors but they did not measure the angle between skulls to be 22.12° and 23.30° on right and left sides, GPF-IF in their study.[8,11] However, Saralaya and Nayak[10] respectively. To our best of literature search, only observed the same but the methodology of estimating the [10] Saralaya and Nayak observed such an angle (right = angle between GPF to midline was not explained by them. 21.1°; left = 21.2°) in Indian skulls. We observed the Moreover, Saralaya and Nayak[10] measured the angle from mean angle between MMS and the line joining IF to GPF anterior border GPF in their study which is questionable on right and left sides as 20.81° ± 2.47°and 20.58° ± due to variations in the shapes of GPF[19,20] but we took 2.69° (P = 0.53) respectively, ranging from 18.73° – measurements from the center of the foramina. We consider 21.25°. Furthermore, the distance between GPF-IF in that the diversity could be a result of factors such as age, right and left sides (37.74 ± 2.39 and 37.89 ± 2.83; P = sex, race and differences in the reference points which are 0.68) mm in our study with minimum to maximum being taken as criteria in the measurements. The wide variability 35.67 mm-42.12 mm. Smaller dimensions between in locating the position of GPF among different population [13] GPF-IF were observed by Chrcanovic et al., and groups warrants the need for studies from different regions [10] Saralaya and Nayak in Brazilian and Indian skulls, of the world. respectively. The possible reason behind smaller diameter arises from the fact that they took the measurement CONCLUSION scale from the anterior wall of the GPF to the posterior border of the IF compared to our study where we had This study helps to determine the precise location and taken dimensions from the center of foramina. They also direction of the GPF (by the angle formed between MMS witnessed a wide range in the measurements advocating and line joining GPF-IF) in relation to various anatomical its high margin of variability. The determination of the structures, in Indian population. The landmarks angle and the distance between GPF-IF is important for described could be identifi ed and effectively applied with medical professionals in directing the needle for precise success in various clinical scenarios, thereby decreasing infi ltration of local anaesthetics to GPF. Moreover, the the risk of failures and complications. diameter between GPF-IF is also helpful in determining the site of GPF in conditions with absent molar tooth and REFERENCES patients with midline palatal defects creating diffi culty in locating MMS. 1. Schwartz AD, Dolev E, Williams W. Maxillary nerve block – a new approach using a computer-controlled anesthetic delivery system for maxillary sinus elevation procedure. A prospectivestudy. In our study, the direction of greater palatine canal on Quintessence Int 2004;35:477-80. the hard palate was observed antero-medially in 60.10% 2. Malamed SF. Handbook of local anesthesia. 4th ed. St Louis: of skulls. The same direction of greater palatine canal Mosby; 1997. p.187-91.

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3. Kamath MR, Mehandale SG, Us R. Comparative study of greater morphology in the position of the palatine foramina in adult human palatine nerve block and intravenous pethidine for postoperative skulls from Greece. J Craniomaxillofac Surg 2012;40:206-10. analgesia in children undergoing palatoplasty. Indian J Anaesth 15. Wang TM, Kuo KJ, Shih C, Ho LL, Liu JC. Assessment of the 2009;53:654-61. relative locations of the greater palatine foramen in adult Chinese 4. Mercuri LG. Intraoral second division nerveblock. Oral Surg Oral skulls. ActaAnat 1988;132:182-6. Med Oral Pathol 1979;47:109-13. 16. Methathrathip D, Apinhasmit W, Chompoopong S, 5. Hamilton WJ. Tratado de anatomiahumana. 2nd ed. Rio deJaneiro: Lertsirithong A, Ariyawatkul T, Sangvichien S. Anatomy of Interamericana; 1982. greater palatine foramen and canal and pterygopalatine fossa 6. Ferreira SS, Reis LR, Gomes JC, Ferreira Junior SS. Análise in Thais: Considerations for maxillary nerve block. Surg Radiol do foramen palatinum majus e canalis palatinus major no Anat 2005;27:511-6. esplancnocrânio humano, para accesso ao bloqueio do nervus 17. Sharma NA, Garud RS. Greater palatine foramen — key to maxilaris. Acta Biol Par 1990;(1,2,3,4):1-19. successful hemimaxillary anaesthesia: A morphometric study and 7. Rizzolo RJ, Madeira MC. Anatomia facial com fundamentos de report of a rare aberration. Singapore Med J 2013;54:152-9. anatomiasistêmicageral. 2nd ed. Sao Paulo: Sarvier; 2006. 18. Vinay KV, Beena DN, Vishal K. Morphometric analysis of the 8. Ajmani ML. Anatomical variation in position of the greater palatine greater palatine foramen in south Indian adult skulls. Int J Basic foramen in the adult human skull.J Anat 1994;184:635-7. Appl Med Sci 2012;2:5-8. 9. Jaffar AA, Hamadah HJ. An analysis of the position of the greater 19. Lopes PT, Santos AM, Pereira GA, Oliveira VC. Morphometric palatine foramen. J Basic Med Sci 2003;3:24-32. analysis of the greater palatine foramen in dry Southern Brazilian adult skulls. Int J Morphol 2011;29:420-3. 10. Saralaya V, Nayak SR. The relative position of the greater palatine foramen in dry Indian skulls. Singapore Med J 2007;48:1143-6. 20. Nimigean V, Nimigean VR, Butincu L, Salavastru DI, Podoleanu L. Anatomical and clinical considerations regarding 11. Sujatha N, Manjunath K, Balasubramanyam V. Variations of the the greater palatine foramen. Rom J Morphol Embryol location of the greater palatine foramina in dry human skulls. 2013;54:779-83. Indian J Dent Res 2005;16:99-102. 12. Hassanali J, Mwaniki D. Palatal analysis and osteology of the hard palate of the Kenyan African skulls. Anat Rec 1984; 209:273-80. How to cite this article: Sharma N, Varshney R, Ray S. Anatomic 13. Chrcanovic BR, Custódio ALN. Anatomical variation in the position and anaesthetic considerations of greater palatine nerve block in of the greater palatine foramen. J Oral Sci 2010;52:109-13. Indian population. Saudi J Med Med Sci 2014;2:197-201. 14. Piagkou M, Xanthos T, Anagnostopoulou S, Demesticha T, Source of Support: Nil. Confl ict of Interest: None declared. Kotsiomitis E, Piagkos G, et al. Anatomical variation and

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