Location of the infraorbital foramen with reference to soft tissue landmarks for regional nerve blocks during midface surgery

Location of infraorbital and accessory infraorbital foramina in Iranian population: a retrospective radiological study with crucial clinical implications

PURPOS

The location of infraorbital foramen (IOF) and the prevalence of accessory IOF vary among different populations. It may lead to infraorbital nerve (ION) blockage during surgery. This study aimed to assess the IOF location and AIOF frequency in Iranian people.

METHOD

In this retrospective cross-sectional study, 500 paranasal sinus computed tomography scans of adults were examined using the INFINITT PACS system.

RESULT

The distance from IOF to infraorbital margin (IOM), mid-pupillary line (MPL), midsagittal line (MSL), canine eminence (CE), and skin thickness (ST) was 8.97 ± 1.79, 5.73 ± 1.84, 24.86 ± 2.23, 20.39 ± 3.47, and 10.90 ± 2.59 mm, respectively. The vertical and transverse diameters of the foramen were 3.03 ± 0.65 and 3.71 ± 0.76 mm, respectively. In addition, the shape of 63.5% of the foramina was oval. The prevalence of AIOF was 9%, and its most common location was superomedial to IOF.

CONCLUSION

We believe that in this study, landmarks like IOM, MPL, MSL, CE and ST could help the clinicians localize IOF and improve the ION anesthesia success rate. Furthermore, the occurrence of AIOF should be considered by physicians to reduce the chance of injuries to the infraorbital neurovascular complex.

Three-point Method Nerve Block for Relieving Pain of Microbotox Injection in Middle and Upper Face

Background

With the popularity of microbotox, pain caused by multiple microdroplets and subcutaneous injection of botulinum toxin is increasing. This study presents a new, refined, three-point nerve block technique that provides effective pain relief during minimally invasive injection therapy targeting the middle and upper face.

Methods

Fifty volunteers underwent facial ultrasonography to measure the locations of the supraorbital and infraorbital foramen. Following microdrop Botox injection of the middle and upper face, 100 patients underwent a self-controlled study to analyze whether a three-point nerve block surpasses topical anesthesia for reducing injection pain. The visual analog scale pain score, the time of the three-point method and botulinum toxin injection, and side effects were recorded.

Results

Among the volunteers, the location of the supraorbital and infraorbital foramen showed no statistical difference between the left and right sides. For the 100 patients (13 men, 87 women) who underwent the three-point nerve block, the visual analog scale pain scores on the experimental side were significantly lower than those on the control side, except in the frontotemporal region (2.46 ± 0.50, 2.42 ± 0.47, P > 0.05). The duration of the unilateral three-point nerve block was 74.8 ± 5.64 seconds. The total injection time was 189.86 ± 26.79 seconds (range 148-286 s).

Conclusions

The three-point method exerted prominent analgesic effects during middle and upper facial treatments, with benefits including a precise block region, high satisfaction, and simple operation technique. Therefore, clinicians can easily master and apply this method.

Location of the accessory infraorbital foramen with reference to external landmarks and its clinical implications

The aim of this study was to define the location of the accessory infraorbital foramen (AIOF) with reference to accessible external landmarks in order to facilitate orbital and oculoplastic surgical procedures in the maxillofacial region. Forty-four hemifaces from 25 cadavers were dissected. The lateral canthus, subnasal point, and lacrimal caruncle were used as anatomic reference points. The AIOF was observed in 8 of the 44 hemifaces (18.2%) and was situated at a mean distance of 7.2 mm superomedial to the IOF. The horizontal distance from the lacrimal caruncle to the AIOF was 0.3 mm. In all cases the AIOF was situated at a point that was no more than 8 mm from the intersection point of a vertical line passing through the lacrimal caruncle and an oblique line joining the lateral canthus and the subnasal point. Surgeons anesthetizing or performing surgical procedures in the maxillofacial region should be aware of the frequency of the AIOF (18.2%) and its location (on the superomedial side of the IOF). We propose that injecting at the intersection point of a vertical line passing through the lacrimal caruncle and an oblique line joining the lateral canthus and the subnasal point would successfully block the accessory branch of the infraorbital nerve. Likewise, surgeons operating in this region should be aware of the location of the AIOF in order to avoid inadvertent iatrogenic injury to a duplicated infraorbital nerve.