Die Bedeutung der Fascia stylopharyngea bei intraoralen Blockadetechniken

Ganglionic Local Opioid Analgesia at the Superior Cervical Ganglion: MRI-Verified Solution Spread

INTRODUCTION

Ganglionic local opioid analgesia (GLOA) at the superior cervical ganglion (SCG) is performed for pain control and is known to be an effective procedure. In this study, we evaluated the spread of the injectate in the area of the SCG. Our expectation was that there would be a correlation between the area and volume of the injectate spread and post-procedural outcome measures.

METHODS

This was a retrospective blinded review of magnetic resonance imaging (MRI) scans. Assessors evaluated the anatomical area of fluid spread, the furthermost spread from midline, any hampered spread and contact of contrast fluid with other structures. The efficacy of GLOA and complications were estimated.

RESULTS

The main solution spread reached from the C1 to C3 vertebrae. The furthest spread in the lateral and sagittal planes was 21.2 and 15.2 mm, respectively. The furthest craniocaudal spread was 63.5 mm. In 53.3% and 33% of interventions, the solution was found in the parapharyngeal space and in its "medial compartment," respectively. A correlation was found between pain relief and both solution spread and volume of solution spread. No hampered spread was recorded. A negative correlation between pain reduction and number of GLOA was observed. Higher pre-procedural pain intensity was correlated with higher pain reduction. We estimated pain relief in 93% of procedures correctly. No correlation between post-procedural Numerical Rating Scale (NRS) scores and different needle approaches was found.

CONCLUSION

For the transoral blocking technique, a strict laterodorsal needle direction is recommended to prevent possible block failures. A total volume of 2 ml injected into the parapharyngeal space and its "medial compartment" is recommended. Higher volumes may lead to uncontrolled distribution patterns.

TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT05257655; date of registration 2022-02-25; patient enrollment date from 2023-01-09 to 2023-08-31.

Surgical Landmarks for Parapharyngeal Internal Carotid Artery During Extended Endoscopic Surgery of Nasopharynx: A Cadaveric and Radiological Study

Nasopharynx is a complex region situated at the center of skull surrounded by various vital neurovascular structures. Surgical access to the nasopharyngeal space poses significant challenges due to the position of the internal carotid artery (ICA). Open approaches to nasopharynx utilize the lateral to medial anatomy but the endoscopic endo-nasal approach warrants knowledge about the medial to lateral anatomy. In this study we attempted to find the consistent surgical landmarks for parapharyngeal portion of internal carotid artery at the level of nasopharynx by means of cadaveric and radiological study. Eight fresh frozen cadavers (16 sides) and 30 CT angiography (60 sides) were included in the anatomical and radiological study respectively. Superior aspect of the torus tubarius was taken as the reference point in cadaveric study and C1-C2 interspace was used as the reference point for the radiological study. The distance between the ICA to the landmarks such as fossa of Rosenmullaer, torus tubarius, medial and lateral pterygoid plates were recorded. The mean distance of ICA to the fossa of Rosenmuller was 8.5 ± 1.4 mm and 9.1 ± 1.1 mm in the cadaveric and radiological study respectively. The mean distance between ICA to torus tubarius was 19.8 ± 1.3 mm in cadaveric and 20.6 ± 1.0 mm in radiological study. The mean distance of ICA to medial and lateral pterygoid plates were 25.3 ± 1.4 mm and 18.2 ± 1.4 mm in the cadaveric study and 25.9 ± 1.2 mm and 18.8 ± 1.3 mm in the radiological study respectively. On correlating the measurements between cadaveric and radiological study, the p values were not statistically significant (p > 0.05). The closest landmark to the ICA was the fossa of Rosenmuller. ICA was located at the same sagittal plane as that of the lateral pterygoid plate. The nasopharynx is a complex anatomical region closely related to ICA. Inadvertent injury to ICA is one of the dreaded complications of nasopharyngeal surgery. Fossa of Rosenmuller is only few millimeters away from the ICA and must be treated very cautiously. During the endoscopic approach, the ICA is at the sagittal plane as of the lateral pterygoid plate. This must be kept in mind when advancing toward the ICA by keeping intact the lateral pterygoid plate when possible and one should stay in the plane of medial pterygoid plate as the ICA lies posterolateral to it. Cadaveric dissections supported by radiological data would definitely aid surgeons to successfully perform surgeries in nasopharynx.

The anatomy of the parapharyngeal segment of the internal carotid artery for endoscopic endonasal approach

Injury to the internal carotid artery (ICA) is a life-threatening complication of endoscopic endonasal approaches. The objective of this study is to illustrate the detail anatomy of the parapharyngeal segment of the ICA (PPICA) to safe endoscopic endonasal surgery. The anatomical dissection was performed in 10 cadaveric specimens and several crucial anatomical landmarks were identified and measured. In addition, 50 dry skulls were studied to further assess the relationship between the pharyngeal tubercle and carotid foramen. From the endoscopic endonasal perspective, in the median plane, the pharyngeal tubercle and the carotid foramen on both sides were located on a line. The average distance between the pharyngeal tubercle and anterior border of the external orifice of the carotid canal was measured as 25.2 ± 3.2 mm. In the paramedian plane, the PPICA was located between the levator veli palatini muscle (LVPM) and the stylopharyngeal muscle (SPM) in upper parapharyngeal space in all specimens, and the distance from the posterior border of the LVPM to the anterior border of the SPM was recorded as 15.1 ± 2.8 mm at the level of the carotid foramen. The distance from the attachment of the LVPM to the anterior border of the external orifice of the carotid canal was about 5.1 ± 0.2 mm. The fully developed stylopharyngeal fascia (SPhF) was observed in 10 cases, and the PPICA was always anteriorly enclosed by and adhered to the SPhF.

[Superior cervical ganglion: an anatomical variant. Are variations of the cranial carotid artery a risk factor for accidental intravascular injection?]

A variation of the cranial carotid artery is demonstrated in an anatomical specimen revealing possible complications of ganglionic local opioid analgesia at the superior cervical ganglion. Located in the area of the puncture site, a loop of the aberrant carotid artery adheres closely to the pharyngeal wall in the medial position, shortening the distance between the arterial lumen and the oral cavity to 5 mm. With an incidence of 25%, an aberrant carotid artery could possibly facilitate an accidental intravascular injection during ganglionic local opioid application at the superior cervical ganglion.