Related Experiment Video
Updated: Feb 13, 2026
12:25
C-arm-Free Simultaneous OLIF51 and Percutaneous Pedicle Screw Fixation in a Single Lateral Position
Published on: September 16, 2022
4.6K
The Ponticulus Posticus as Risk Factor for Screw Insertion into the First Cervical Lateral Mass
Dilek Arslan1, Mehmet Asim Ozer2, Figen Govsa2
1Department of Neurosurgery, Tepecik Research and Training Hospital, Izmir, Turkey.
World Neurosurgery
|February 28, 2018
Summary
Ponticulus posticus (PP) is an anatomical variation affecting the C1 vertebra. Awareness of PP is vital to prevent vertebral artery (VA) injury during cervical spine surgery.
Area of Science:
- Anatomy
- Neurosurgery
- Radiology
Background:
- Ponticulus posticus (PP) is an osseous anomaly of the C1 vertebra.
- Awareness of PP is crucial for preventing vertebral artery (VA) injuries during C1 instrumentation.
Purpose of the Study:
- To investigate ponticulus posticus (PP) and its relationship with the vertebral artery (VA).
- To assess the utility of PP and VA as intraoperative landmarks using 3D CT angiography.
Main Methods:
- Investigated PP and VA as intraoperative landmarks.
- Measured intersections of VA to C1 posterior arch and medial line.
- Measured C1 posterior arch and VA curve around lateral masses.
Main Results:
- PP identified in 14.3% of samples, more common in women and on the right side.
- In PP cases, VA showed variable courses; distances to C1 posterior arch were larger, and curves around lateral masses were narrower.
- 3D models revealed PP's effect on VA; safe lateral mass screw fixation (>4 mm) was not influenced by PP.
Conclusions:
- The PP loop can reduce space for C1 screw placement.
- Standard screw techniques are contraindicated due to high risk of VA injury in PP cases.
Related Concept Videos
01:26Factors Affecting the Risk of Infection
13.9K
The hosts' susceptibility to infection depends on several factors. The integrity of the skin and mucous membranes helps protect the body against microbial attacks. When the skin is altered, the chance of infection, limb loss, and even death increases.
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin...
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin...
13.9K
01:24Drug Toxicity: Risk factors
2
Adverse Drug Reactions (ADRs) are potential complications that arise during pharmacotherapy, influenced by multiple risk factors. Age plays a significant role; both neonates and the elderly are at heightened risk due to their respective immature and diminished metabolic and elimination processes. Gender also impacts ADRs, with females experiencing a 1.5 to 1.7-fold greater risk than males, which may be linked to pharmacokinetic, pharmacodynamic, and hormonal differences. Notably, neonates, the...
2
01:21Screw: Problem Solving
710
In mechanical engineering, the interaction between a threaded screw shaft and a plate gear involves analyzing the resisting torque on the plate gear that can be overpowered when a specific torsional moment is applied to the shaft. To better comprehend this concept, consider a generic situation with a threaded screw shaft with a given mean radius and lead and a plate gear with a specified mean radius. The coefficient of static friction between the screw and gear is also provided.
To evaluate the...
To evaluate the...
710
01:16Self-Locking Screw
2.5K
A square-threaded screw jack is a mechanical device widely used for lifting heavy loads or applying considerable force. One of the key features that can make a screw jack more effective and reliable is its self-locking capability.
A square-threaded screw jack carrying a load is considered self-locking if the screw retains its position even after the moment applied to it is removed.
A square-threaded screw jack carrying a load is considered self-locking if the screw retains its position even after the moment applied to it is removed.
2.5K
01:17Frictional Forces on Screws
1.6K
Screws are characterized by a helical ridge known as a thread wrapped around a cylindrical shaft. They are commonly used as fasteners to hold objects together or to transmit power and motion in machines. One type of screw that is particularly useful for transmitting power is the square-threaded screw.
A jack with a square-threaded screw is a mechanical device used to lift heavy loads by applying a force at its handle. When the force is applied, the screw turns, raising the load. The screw can...
A jack with a square-threaded screw is a mechanical device used to lift heavy loads by applying a force at its handle. When the force is applied, the screw turns, raising the load. The screw can...
1.6K
01:12Relative Risk
2.2K
Relative risk (RR) is a statistical measure commonly used in epidemiology to compare the likelihood of a particular event occurring between two groups. This metric is important for evaluating the relationship between exposure to a specific risk factor and the probability of a particular outcome. It plays a crucial role in medical research, public health studies, and risk assessment. Relative risk quantifies how much more (or less) likely an event is to occur in an exposed group compared to an...
2.2K