Protection of the innervation of the tensor fasciae latae in hip direct anterior and anterolateral approaches: a cadaver study

PURPOSE

This study aims to reveal the exact course of the superior gluteal nerve (SGN) branch innervating the tensor fascia lata (TFL) and show how it can be protected in the direct anterior approach (DAA) and anterolateral approach (ALA).

METHODS

The anterolateral regions of 22 thighs from formalin-fixed cadavers were dissected. 3 anatomical points were determined. Point A, B, C indicates where the SGN enters the gluteus minimus (GMin) fibres, the SGN leaves the gluteal muscles, the SGN enters the TFL, respectively. Measurements were made on 3 separate lines.

RESULTS

On the anterior superior iliac spine (ASIS) and the head of the fibula line (Line 1), the horizontal-vertical distances from point B and C to the ASIS were 7.99 ± 3.65 mm-40.40 ± 11.50 mm and 11.74 ± 6.61 mm-70.35 ± 14.11 mm respectively. The horizontal-vertical distances from point A, B, C to the greater trochanter (GT) were 32.41 ± 9.97 mm-55.28 ± 12.25 mm; 67.70 ± 8.54 mm-17.76 ± 13.57 mm; 63.92 ± 9.96 mm-13.00 ± 7.92 mm on the GT and the head of the fibula line (Line 2), respectively. The horizontal-vertical distances from point A, B, C to the GT were 24.58 ± 9.83 mm-42.54 ± 12.86 mm; 9.45 ± 7.92 mm-36.25 ± 9.06 mm; 26.18 ± 11.12 mm-64.05 ± 11.67 mm on the ASIS and the GT line (Line 3).

CONCLUSIONS

In the DAA, the increased risk of damaging the branch of the SGN that innervates the TFL must be kept in mind. The protection of this branch can be ensured with easy and applicable rules.

Microsurgical anatomy of the anterior cerebral artery and the arterial supply of the cingulate gyrus

PURPOSE

The cingulate gyrus is a potential surgical area to treat tumours, psychiatric diseases, intractable pain and vascular malformations. The aim of the study was to define the topographic anatomy and arterial supply of the cingulate gyrus located on the medial surface of the cerebral hemisphere.

METHODS

We studied thirty-six hemispheres, each hemisected in the midsagittal plane. The vertical thickness of the cingulate gyrus was measured at the anterior commissure (AC), posterior commissure (PC), and genu levels of the corpus callosum. The branches of the anterior and posterior cerebral arteries supplying each zone were noted separately. The arterial pathways were transformed to digital data in AutoCAD to identify the condensation and reduction areas.

RESULTS

The mean AC-PC distance was 27.17 ± 1.63 mm. The thinnest region was the genu level of the corpus callosum (10.29 mm). The superior internal parietal artery (SIPA), inferior internal parietal artery (IIPA) and pericallosal artery (PrCA) supplied all zones of the cingulate gyrus. The anterior zone received the greatest supply. The arterial condensation and reduction areas on both sides of cingulate gyrus and its x, y, and z coordinates specified.

CONCLUSIONS

The target cingulotomy (TC) area was determined for anterior cingulotomy. The properties of the TC area are that the thinnest region of the cingulate gyrus is supplied relatively less than other areas and is close to the anterior cingulotomy areas in the literature. The arterial reduction area (ARA) was found to be suitable for corpus callosotomy in terms of avoiding haemorrhage.

Topographical Anatomy of the Superficial Temporal Artery

AIM

This study was conducted to describe in detail the gross anatomy of the superficial temporal artery (STA), its course and branches, its relationships with the branches of the facial nerve, and certain anatomical and surgical landmarks to preserve these structures in daily neurosurgical practice and use the STA during revascularization surgery.

MATERIAL AND METHODS

This cadaveric study was conducted on 16 cadaver heads bilaterally, in which 32 silicon/latex-injected STAs were dissected using a microdissection technique in a neuroanatomy laboratory. The distances between the facial nerve, tragus, STA, superficial temporal vein (STV), and imaginary lines created between important anatomical landmarks were measured. The curvilinear lengths of STA and STV were also measured.

RESULTS

The average distances of the most posteriorly located branch of the facial nerve to the frontal region and the tragus at the midpoint of zygoma in the horizontal plane, at the superior border of the zygoma and at the level of the superior border of the parotid gland, were measured as 25.39, 29.84, and 15.56 mm, respectively. The average distance directly measured between the tragus and STA was 39.29 mm, and that between the tragus and STV was 20.26 mm. The average curvilinear lengths of the frontal and parietal branches of STA were 97.63 and 96.45 mm, respectively.

CONCLUSION

Understanding the clinical anatomy of the STA and its branches and its relationships with other structures is of critical importance for a successful and noncomplicated surgery. Our findings will be useful not only for surgical approaches such as pterional craniotomy and orbitozygomatic approaches but also for cerebral revascularization.

Morphology of the trigeminal ganglion: anatomical structures related to trigeminal radiofrequency rhizotomy

BACKGROUND

Trigeminal neuralgia is the most common example of craniofacial neuralgia. Its etiology is unknown and is characterized by severe episodes of paroxysmal pain. The trigeminal ganglion and its adjacent anatomical structures have a complex anatomy. The foramen ovale is of great importance during surgical procedures such as percutaneous trigeminal rhizotomy for trigeminal neuralgia.

OBJECTIVE

We aimed to identify the anatomical structures associated with the trigeminal ganglion and radiofrequency rhizotomy on cadavers and investigate their relationship with the electrodes used during rhizotomy to determine the contribution of the electrode diameter and length to the effectiveness of the lesion formation on the ganglion.

METHODS

Five fresh-frozen cadaver heads injected with red silicone/latex were used. A percutaneous puncture was made by inserting of a cannula through the foramen ovale to create a pathway for electrodes. The relationships between the electrodes, Meckel's cave, trigeminal ganglion, and neurovascular structures were observed and morphometric measurements were obtained using a digital caliper.

RESULTS

Trigeminal ganglion, therefore the electrode in its final position, shows proximity with important anatomical structures. The electrode was inserted posteriorly into the foramen ovale in all of the specimens and was located on the retrogasserian fibers. This study revealed that the electrodes targeting the ganglion and passing through the foramen ovale may cause a radiofrequency lesion due to the contact effect of the dura itself pressing on the electrode. Pushing the cannula beyond the petroclival angle may result in puncturing of the dura propria and moving further away from the target area.

CONCLUSION

The success of radiofrequency rhizotomy is directly related to the area affected by the lesion. Understanding the mechanism of action underlying this procedure will ensure the effectiveness, success, and sustainability of the treatment.

Anatomic Analysis of the Internal and External Aspects of the Pterion

OBJECTIVE

The pterion is an H-shaped suture complex. This study's goal was to determine the location of its external and internal surfaces and extension and emphasize and discuss its surgical importance.

METHODS

Fifty dried adult human skulls were obtained from the Department of Anatomy. A 2-mm drill bit was placed externally over the pterion, and the pterion was drilled through the bone perpendicular to the skull's surface.

RESULTS

The midpoint of the H shape in the pterion area was not at the same level on the skull's external and internal pterion surfaces. According to these measurements, the external pterion lay above the internal pterion when the skull was viewed externally. Furthermore, the internal pterion was on average longer than the external pterion. The internal and external pterions were schematized such that the skull was viewed from the outside. These areas were divided into 4 quadrants (anterior-superior, anterior-inferior, posterior-superior, and posterior-inferior) by a vertical and horizontal line. In 30 cases (60%), sulci of the middle meningeal artery's parietal branches entered the posterior-superior quadrant on the bone, whereas the artery's frontal branches were located in the anterior-superior and anterior-inferior quadrants, and the Sylvian fissure's origin was in the posterior-inferior quadrant.

CONCLUSIONS

By using a subdivision into 4 quadrants, and considering our anatomic findings, we determined the way surgical procedures can be performed more easily and reliably. Even with modern localization technologies, anatomic landmarks can be useful to the neurosurgeon.