Morphometric and Topographic Features of Stylomastoid Foramen and its Clinical Significance in Facial Nerve Block

Abstract

Objective This study aims to determine the topographic localization of the stylomastoid foramen (SF) and its morphometric relationship with the surrounding bony landmarks.

Design A descriptive anatomical study.

Setting Anatomy Laboratory of the Faculty of Medicine.

Participants Measurements were performed on 53 dry temporal bones.

Main Outcome Measures On the inferior and lateral aspects of photographic images, lines and angles were defined. The most lateral end of the SF (SF1) and the transverse medial–lateral line that passes through the upper end of the anterior border of mastoid process (line 1) were used as reference points for topographic evaluation. The upper end of the anterior border of mastoid process (A) and the tip of mastoid process (B) were considered in defining angles. The dates about SF were evaluated using the ImageJ 1.46r software and digital caliper.

Results SF1 was classified into three different types based on its topographical localization, stated as Type 1, Type 2, and Type 3. In Type 1, SF1 was located anterior to line 1 (54.7%). SF1 was located posterior to line 1 in Type 2 (34.0%). SF1 was located just over line 1 in Type 3 (11.3%). We also detected angular variations between these types in the inferior and lateral aspects.

Conclusion The recommended angles of application are 30 degrees on the horizontal plane and 55 degrees on the sagittal plane for Type 1 when point B is considered. A needle length below 10 mm is more suitable to minimize the potential complications of the nerve block.

Keywords

stylomastoid foramen - Nadbath block - morphometry

Publication History

Received: 15 August 2019

Accepted: 24 December 2019

Article published online:
06 March 2020

• References

• 1 Schimek F, Fahle M. Techniques of facial nerve block. Br J Ophthalmol 1995; 79 (02) 166-173
• 2 Takahashi T, Dohi S. Hemifacial spasm: a new technique of facial nerve blockade. Br J Anaesth 1983; 55 (04) 333-337
• 3 Garg A. Anesthesia in cataract surgery. In: Agarwal S, Agarwal A, Agarwal A. eds. Phacoemulsification. New Delhi: Taylor & Francis; 2004. -162
• 4 Nadbath RP. Rehmani. Facial nerve block. Am J Ophthalmol 1963; 55: 143-146
• 5 Wong DHW. Regional anaesthesia for intraocular surgery. Can J Anaesth 1993; 40 (07) 635-657
• 6 Garg A. Anesthesia in cataract surgery. In: Garg A, Fry LL, Tabin G, Pandey SK, Gutierrez-Carmona FJ. eds. Clinical Practice in Small Incision Cataract Surgery. New Delhi: Taylor & Francis; 2004: 224
• 7 Spaeth GL. Total facial nerve palsy following modified O'Brien facial nerve block. Ophthalmic Surg 1987; 18 (07) 518-519
• 8 Koenig SB, Snyder RW, Kay J. Respiratory distress after a Nadbath block. Ophthalmology 1988; 95 (09) 1285-1287
• 9 Cofer HF. Cord paralysis after Nadbath facial nerve block. Arch Ophthalmol 1986; 104 (03) 337
• 10 Standring S. Grays's Anatomy: The Anatomical Basis of Clinical Practice. 41th ed. London: Elsevier; 2016: 416
• 11 O'Brien CS. Local anesthesia in ophthalmic surgery. JAMA 1928; 90: 8-13
• 12 Van Lint H. Paralysie palpebrale temporaire provoquee dans l'operation de la cataracte. Ann Ocul (Paris) 1914; 151: 420-424
• 13 Atkinson WS. Akinesia of the orbicularis. Am J Ophthalmol 1953; 36 (09) 1255-1258
• 14 Khurana AK. Ophthalmology. New Delhi: New Age International Ltd; 2003: 572
• 15 Birt CM, Dixon WS, Dionne CL. Vocal cord paralysis with Nadbath facial block. Can J Ophthalmol 1994; 29 (05) 231-233
• 16 Gray AT, Hynson JM. Pulmonary edema after Nadbath and retrobulbar blocks. Anesth Analg 1994; 78 (06) 1177-1179
• 17 Rabinowitz L, Livingston M, Schneider H, Hall A. Respiratory obstruction following the Nadbath facial nerve block. Arch Ophthalmol 1986; 104 (08) 1115
• 18 Shoch D. Complications of the Nadbath facial nerve block. Arch Ophthalmol 1986; 104 (08) 1114-1115
• 19 Sharma N, Varshney R. Morphometry of stylomastoid foramen and its clinical application in facial nerve block. Saudi J Anaesth 2015; 9 (01) 60-63
• 20 Lindquist TD, Kopietz LA, Spigelman AV, Nichols BD, Lindstrom RL. Complications of Nadbath facial nerve block and a review of the literature. Ophthalmic Surg 1988; 19 (04) 271-273
• 21 Wilson CA, Ruiz RS. Respiratory obstruction following the Nadbath facial nerve block. Arch Ophthalmol 1985; 103 (10) 1454-1456