Percutaneous retrograde posterior column acetabular fixation: is the sciatic nerve safe? A cadaveric study

Area of Science:

• Orthopedic surgery
• Anatomy
• Surgical safety

Background:

• Acetabular fractures often require surgical fixation.
• Percutaneous screw fixation through the ischial tuberosity is a common approach.
• Understanding the proximity of neurovascular structures is crucial for surgical safety.

Purpose of the Study:

• To determine the spatial relationship between screws inserted percutaneously into the ischial tuberosity and adjacent neurologic structures.
• To assess the risk of nerve injury during retrograde percutaneous screw fixation for posterior column acetabular fractures.

Main Methods:

• A cadaveric study involving 10 limbs from 5 cadavers.
• Fluoroscopic guidance was used for screw insertion into the ischial tuberosity.
• Post-insertion dissection was performed to measure distances to the sciatic nerve, posterior cutaneous nerve of the thigh, and inferior cluneal nerves.

Main Results:

• The sciatic nerve (average 58 mm) and posterior cutaneous nerve of the thigh (average 42 mm) were at a safe distance from the screw.
• The inferior cluneal nerves were significantly closer (average 3.5 mm) and were injured in 3 specimens.
• In one specimen, the inferior cluneal nerves could not be located.

Conclusions:

• Retrograde percutaneous screw fixation through the ischial tuberosity is likely safe for the sciatic and posterior cutaneous nerves.
• The inferior cluneal nerves are at considerable risk of injury, potentially affecting cutaneous sensation in the gluteal region.
• Caution is advised to avoid injury to the inferior cluneal nerves during this surgical technique.