MedTrace Logo

Continuous Intraocular Pressure Patterns in Spine Surgery

NCT03299400 · Status: COMPLETED · Phase: NA · Type: INTERVENTIONAL · Enrollment: 10

Last updated 2020-05-06

No results posted yet for this study

Summary

Post-operative visual loss is a rare but serious complication after surgery. It is most significantly correlated with prone spinal surgery with a prolonged duration. The cause and risk factors are not elucidated, but the majority of the cases are due posterior ischaemic optic neuropathy (PION). This entity is directly related to the ocular perfusion pressure (OPP), which is estimated as the difference between mean arterial blood pressure (MAP) and intraocular pressure (IOP). Autoregulation is believed to maintain a constant perfusion to the optic nerve despite fluctuations in the perfusion pressure.

IOP is known to increase in the prone position thus putting susceptible patients at risk for inadequate ocular nerve perfusion. Most of the evidence comes from animal and healthy volunteer studies and cannot give an accurate insight into the subtle changes of intra-operative IOP. All the published studies employed the use of a tonometer, which may have rooms for measurement errors due to inadvertent pressure on the globe while retracting the eyelids, particularly when there is significant periorbital/conjunctival swelling in the prone position. The majority of the studies recruited healthy volunteers in a simulated surgical setting so other fluctuating parameters, which can affect intraoperative IOP, cannot be measured. In the few reports where patients undergoing surgery in the prone position were studies, IOP measurements were taken at non-continuous monitoring at time intervals, thus the effects of changes in blood volume, MAP, central venous pressure (CVP) and PaCO 2 could not be studied. Lastly, all the literature consists of case series only with no control group so the effect of position cannot be evaluated independently of the other factors.

The investigators therefore propose to conduct a prospective study with continuous intraoperative IOP monitoring to give us further insight into the physiological changes of IOP in patients undergoing spine surgery, and identify the risk factors related to fluctuations of IOP during prone spinal surgery.

Conditions

  • Intraocular Pressure

Interventions

DEVICE

Contact lens sensor

Patient will continue to wear the contact lens postoperatively for a total of 24 hours or until the patient cannot tolerate the contact lens. After removal of the contact lens sensor, the recorded profiles will be collected and visualized graphically on a computer interface.

Sponsors & Collaborators

  • The University of Hong Kong

    lead OTHER

Principal Investigators

  • Dr Kenny Kwan, BMBCh(Oxon) · The University of Hong Kong

Study Design

Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Model
SINGLE_GROUP

Eligibility

Min Age
18 Years
Max Age
80 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2016-05-09
Primary Completion
2017-05-09
Completion
2017-05-09

Countries

  • Hong Kong

Study Locations

More Related Trials

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT03299400 on ClinicalTrials.gov