Improved Understanding of Venous Drainage at the Cranio-cervical Junction : Study of Postoperative Venous Remodeling Following Surgical Treatment of Lesions of the Posterior Fossa or Posterior Approach of the Upper Cervical Spine.

Overview

In the literature, a dichotomous view of cerebral venous drainage is most commonly found. Thus, two drainage pathways are most often considered: the jugular vein network and the vertebral artery plexus. However, several clinical observations seem to indicate a much more complex situation. The following hypothesis is therefore put forward: there are alternative drainage pathways to these main pathways, which are physiologically present and capable of draining a significant volume of blood. A set of alternative pathways, which can be described as "deep," has been described: in particular, drainage pathways surrounding the vertebral artery (vertebral artery venous plexus), epidural plexuses, and deep cervical veins. However, the so-called "superficial" systems (subcutaneous and muscular) do not appear to have been studied. There appears to be a change in venous drainage of the craniocervical junction postoperatively (posterior cranial fossa surgery and posterior approach to the upper cervical spine). These modifications would vary depending on the venous drainage configuration present in each patient. If this hypothesis is confirmed, it could have an impact on the management of each patient. Thus, if venous remodeling models are established, this could enable personalized perioperative patient management: better optimization of body position during installation in the operating room, more effective anticipation of potential intraoperative venous bleeding, and explanation of persistent headaches in the postoperative period due to insufficient compensation of venous drainage. Confirmation of this hypothesis would also improve the understanding of certain pathologies for which the venous hypothesis has been raised (chronic hydrocephalus in adults, idiopathic intracranial hypertension, etc.).

Detailed description

Inclusion:

The inclusion visit will take place during an initial neurosurgery consultation. If the patient meets the inclusion and exclusion criteria and wishes to participate in this study, the study investigator will obtain the patient's consent.

During this visit, a routine MRI will be performed if the patient has not already had one. In addition to the standard procedure, this MRI will include the study-specific T1 GRE GADO MRI sequence, which will add approximately 3 minutes to the usual examination. The patient will also undergo a routine neurological clinical examination and data about them will be collected (informative data about the patient (age, sex, BMI, etc.), medical history, neurological functional signs, reason for treatment, and neurological clinical examination).

First follow-up visit:

During hospitalization in the neurosurgery department, the patient will undergo a routine neurological clinical examination and data will be collected intraoperatively (duration of surgery, blood loss, ligation/clipping/any interventions on venous structures, intraoperative hemorrhage, other complications of all types) as well as early postoperative data (complications, types, headaches).

The time between the preoperative visit and surgery varies and may depend on the patient's surgical indication.

Second follow-up visit:

Finally, the patient will be asked to come to the neurosurgery department for a post-operative visit a few weeks after their surgery.

This visit is part of standard practice and includes a clinical neurological examination.

During this visit, a second MRI will be performed using the specific sequence for the study, T1 GRE GADO, which will add approximately 3 minutes to the routine examination. Data concerning the patient will be collected (complications, types, headaches).

Interventions

• Procedure T1 GRE GADO MRI sequence
  Addition of a T1 gradient echo sequence with gadolinium (T1 TFE GADO) during the two MRI scans performed in routine practice before and after neurosurgery.

Primary outcome measures

• Dominant network before and after surgery in the craniocervical junction [Time frame: Pre-surgery MRI (performed up to 12 weeks before surgery) + Post-surgery MRI (performed between 10 days and 16 weeks after surgery)]

Secondary outcome measures (5)

• Dominant network before and after surgery in the craniocervical junction and type of surgery [Time frame: Pre-surgery MRI (performed up to 12 weeks before surgery) + Post-surgery MRI (performed between 10 days and 16 weeks after surgery)]
• Dominance (right/left) of venous drainage before and after surgery [Time frame: Pre-surgery MRI (performed up to 12 weeks before surgery) + Post-surgery MRI (performed between 10 days and 16 weeks after surgery)]
• Total surface area of vessels before and after surgery, overall and within each venous network of the craniocervical junction. [Time frame: Pre-surgery MRI (performed up to 12 weeks before surgery) + Post-surgery MRI (performed between 10 days and 16 weeks after surgery)]
• Total surface area of vessels before and after surgery and initial dominance [Time frame: Pre-surgery MRI (performed up to 12 weeks before surgery) + Post-surgery MRI (performed between 10 days and 16 weeks after surgery)]
• Vessel diameter according to internal assessment and senior radiologist [Time frame: Pre-surgery MRI (performed up to 12 weeks before surgery) + Post-surgery MRI (performed between 10 days and 16 weeks after surgery)]

Eligibility criteria

Inclusion criteria

Patient:

• Adult
• Surgery of the posterior cranial fossa or posterior approach to the upper cervical spine, regardless of indication, performed in the neurosurgery department at Brest University Hospital
• Having undergone an MRI with T1 echo gradient sequence with gadolinium (T1 TFE GADO)
• Affiliated with a Social Security scheme
• Having given written consent to participate in the study

Exclusion criteria

• Pregnant or breastfeeding women
• Allergy to gadolinium
• Any contraindications to undergoing an MRI scan (incompatible medical device implant, claustrophobia, etc.)
• Patients unable to understand the protocol
• Patients under guardianship or conservatorship
• Patients subject to a future protection order, family authorization, or legal protection

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Prevention

Study locations

France · 1 center

• CHU Brest — Brest

Identifiers

NCT: NCT07206667 · 29BRC24.0305 · 2025-A00646-43

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗