Retrosigmoid approach assisted by high-resolution computed tomography: a cost-effective technique to identify the transverse and sigmoid sinus transition

Anatomical and Radiological Analysis of Structures of Petrous Part of the Temporal Bone and Their Impact on Area of Anterior Petrosectomy

BACKGROUND

Anterior petrosectomy (AP) is a commonly recognized approach for accessing tumors located in the petrous apex region. The essence of AP lies in drilling the petrous part of the temporal bone within the Kawase quadrangle. In our study, we conducted radiological and anatomical analyses of the structures within the petrous portion of the temporal bone, evaluating their impact on the surgical field during AP.

METHODS

We conducted an analysis of 15 anatomical specimens and 20 3D reconstructions based on computed tomography scans of the middle ear. The analyzed structures included the impression of the trigeminal nerve, the groove of the greater petrosal nerve, the arcuate eminence, and the angle between eminentia arcuata and grove for greater petrosal nerve.

RESULTS

The mean surface area measured by radiological methods does not deviate significantly from the mean surface area measured by anatomical methods 276.265mm2 (interquartile range: 217.603-309.188) versus 233.21mm2 (interquartile range: 210.923-255.453) P = 0.051. We established a threshold 195,99mm2 for radiological determination of the surface area at which another approach should be considered. Additionally, we have developed corrections for specific radiological factors to enable a better assessment of anatomical conditions.

CONCLUSIONS

Our results indicate that preoperative assessment of anatomical conditions based on 3D reconstructions of computed tomography of the middle ear can be a valuable tool in preoperative planning of surgery on tumors in the petroclival region using the AP. Further studies involving a larger sample size are necessary to validate the findings of our study.

Advanced Surgical Techniques for Dural Venous Sinus Repair: A Comprehensive Literature Review

The dural venous sinus (DVS) is a thin-walled blood channel composed of dura mater that is susceptible to injury during common neurosurgical approaches. DVS injuries are highly underreported, which is reflected by a lack of literature on the topic. Neurosurgeons should be familiar with appropriate techniques to successfully repair an injured DVS and prevent associated complications. This study presents a literature review on the surgical techniques for DVS repair after DVS injury during common neurosurgical approaches. The databases PubMed and Scopus were queried using the terms "cranial sinuses," "superior sagittal sinus," "transverse sinuses," "injury," and "surgery." A total of 117 articles underwent full-text review and were analyzed for surgical approach, craniotomy, lesion location, lesion characteristics, and surgical repair techniques. A literature review was performed, and a comprehensive summary is presented. Data from publications describing DVS lacerations related to pathological conditions (eg, meningioma) were excluded. A total of 9 techniques aiding with bleeding control, hemostasis, and sinus repair and reconstruction were identified, including compression, hemostatic agents, bipolar cautery, dural tenting and tack-up suturing, dural flap, direct suturing, autologous patch, venous bypass, and ligation. The advantages and drawbacks of each technique are described. Multiple options to treat DVS injuries are available to the neurosurgeon. Treatment type is based on anatomic location, complexity of the laceration, cardiovascular status, the presence of air embolism, and the dexterity and experience of the surgeon.

Safe Region of Craniotomy to Access the Cerebellopontine Region by Retrosigmoid Approach: A Radiological and Anatomical Study

Accurately positioning the sigmoid sinus (SS), transverse sinus (TS), and vertebral artery (VA) is significantly important during the retrosigmoid (RS) approach. This study aimed to use emissary vein and digastric point as landmarks in high-resolution computer topographic image to locate the SS, TS, and VA to help surgeons to avoid injuring these vascular structures during RS craniotomy. Computed topographic (CT) angiography images of 107 individuals were included, the measurement was performed on coronal, sagittal, and axis planes after the multiplanar reformation. Distance from the emissary vein and digastric point to the posterior boundary of the SS, inferior boundary of the TS were measured by CT angiography preoperatively and in the skull intraoperatively. The VA was also located by emissary vein and digastric point. No significant difference was identified between the distances measured in the CT and skull. Our findings provide anatomical information for locating the boundary of the SS, TS, and V3-VA based on the fixed bony landmarks. Verified by skull measurement, high-resolution CT scan is a cost-effective and reliable tool for identifying the location of the arteries and sinus, which could be widely used to guarantee the safety of RS approach craniectomy.