Santhanam Suresh1, Polina Voronov, John Curran. 1. Department of Pediatric Anesthesiology, Children's Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, IL 60614, USA. ssuresh@northwestern.edu
Abstract
BACKGROUND AND OBJECTIVES: Infraorbital nerve blocks are performed in children undergoing cleft-lip surgery and endoscopic sinus surgery. The nerve exits the maxilla at the level of the infraorbital foramen. A sensory block of the infraorbital nerve can be performed by use of an intraoral route or an extraoral route. The objective of this study was to derive a mathematical formula to determine the position of the infraorbital foramen. METHODS: Computerized tomographic (CT) scans of children who were admitted to our institution for various reasons were evaluated with the assistance of a pediatric neuroradiologist. The distance of the foramen from the midline was determined, and a mixed-effects linear-regression model was used (PROC MIXED in SAS 9.1) to ascertain whether the distance of the infraorbital foramen correlated linearly with the age of the patient. RESULTS: CT scans of 48 pediatric patients were evaluated. The age of the patient accounted for more than half of the variation in this model. Distance of the infraorbital foramen can be predicted by use of the following formula: [Distance of the infraorbital foramen (in mm) from midline = 21.3 + 0.5 x age (in years)]. CONCLUSIONS: Our study found a linear correlation with age to the distance of the infraorbital foramen. This anatomic knowledge of the location of the infraorbital foramen may facilitate correct positioning of the needle. Future studies on the use of this formula with anatomic coordinates should be performed to test the validity of this formula.
BACKGROUND AND OBJECTIVES: Infraorbital nerve blocks are performed in children undergoing cleft-lip surgery and endoscopic sinus surgery. The nerve exits the maxilla at the level of the infraorbital foramen. A sensory block of the infraorbital nerve can be performed by use of an intraoral route or an extraoral route. The objective of this study was to derive a mathematical formula to determine the position of the infraorbital foramen. METHODS: Computerized tomographic (CT) scans of children who were admitted to our institution for various reasons were evaluated with the assistance of a pediatric neuroradiologist. The distance of the foramen from the midline was determined, and a mixed-effects linear-regression model was used (PROC MIXED in SAS 9.1) to ascertain whether the distance of the infraorbital foramen correlated linearly with the age of the patient. RESULTS: CT scans of 48 pediatric patients were evaluated. The age of the patient accounted for more than half of the variation in this model. Distance of the infraorbital foramen can be predicted by use of the following formula: [Distance of the infraorbital foramen (in mm) from midline = 21.3 + 0.5 x age (in years)]. CONCLUSIONS: Our study found a linear correlation with age to the distance of the infraorbital foramen. This anatomic knowledge of the location of the infraorbital foramen may facilitate correct positioning of the needle. Future studies on the use of this formula with anatomic coordinates should be performed to test the validity of this formula.