Effects of the Prone and the Sitting Positions on the Brain Oxygenation in Posterior Fossa Surgery

The sitting or prone positions are used for posterior fossa surgery. Although the sitting position may cause hemodynamic instability, venous air embolism, it also provides optimum access to midline lesions, decreases intracranial pressure. The sitting position has not been only used in neurosurgery, it has been also used in the shoulder surgery. The sitting position related hypotension may reduce the cerebral perfusion pressure, therefore may cause cerebral ischemia. The sitting position related cerebral ischemia has been shown in the shoulder surgery. The non invasive cerebral oxymetry (INVOS-Covidien) has been used to measure cerebral oxygen saturation. Some studies has been done to investigate whether the sitting position cause cerebral desaturation or not in the shoulder surgery by non invasive cerebral oxymetry. The study results are controversial.

It has been investigated that the effect of the prone position on the cerebral oxygenation in the spine surgery and the investigators found that the prone position may increase cerebral oxygenation.

However, all studies have been done in patients without intracranial pathology. We speculate that due to the sitting position reduces the intracranial pressure, it may improve the cerebral oxygenation in the patients have intracranial pathology. Therefore we will compare the sitting and the prone positions effects on the cerebral oxygenation in patients undergoing posterior fossa tumour surgery by non invasive cerebral oxymetry.

Method: 62 patients have posterior fossa tumour will include the study. Patients will divide to 2 groups according to the surgical position, the prone (n=31) or the sitting (n=31). Patients heart rate, mean blood pressure (MAP), cerebral oxygen saturation (SctO2), peripheral oxygen saturation (SpO2), BIS values will record before the induction of anesthesia. Five minutes after the standard anesthesia induction all values will record and it will accept as a baseline. After that all these parameters will record in each 3 minutes until the beginning of surgery. Mean while, more than 5 % reduction in SctO2 and more than 20 % reduction in SctO2 and/or MAP will record. As well as, if the SctO2 reduces than 55 and 60 %, it will record.

Study Overview

• Status: Unknown
• Conditions: Infratentorial Neoplasms
• Intervention / Treatment: Device: SctO2; Device: BIS

Detailed Description

The sitting or prone positions are used for posterior fossa surgery. Although the sitting position may cause significant complications such as including hemodynamic instability, venous air embolism, paradoxical air embolism (PAE), pneumocephalus, peripheral neuropathy, quadriplegia and macroglossia, it also provides optimum access to midline lesions in posterior fossa and cervical spine, improves blood and cerebral spinal fluid drainage, decreases intracranial pressure, lowers airway pressure, and improves access to the endotracheal tube and ability to observe the face for signs of cranial nerves stimulations. The sitting position has not been only used in neurosurgery, it has been also used in the shoulder surgery. The sitting position related hypotension may reduce the cerebral perfusion pressure, therefore may cause cerebral ischemia. The sitting position related cerebral ischemia has been shown in the shoulder surgery.

The non invasive cerebral oxymetry (INVOS-Covidien) has been used to measure cerebral oxygen saturation. Some studies has been done to investigate whether the sitting position cause cerebral desaturation or not in the shoulder surgery by non invasive cerebral oxymetry. The study results are controversial.

It has been investigated that the effect of the prone position on the cerebral oxygenation in the spine surgery and the investigators found that the prone position may increase cerebral oxygenation.

However, all studies have been done in patients without intracranial pathology. We speculate that due to the sitting position reduces the intracranial pressure, it may improve the cerebral oxygenation in the patients have intracranial pathology. Therefore we will compare the sitting and the prone positions effects on the cerebral oxygenation in patients undergoing posterior fossa tumour surgery by non invasive cerebral oxymetry.

Method: 62 patients have posterior fossa tumour will include the study. Patients will divide to 2 groups according to the surgical position, the prone (n=31) or the sitting (n=31). Patients heart rate, mean blood pressure (MAP), cerebral oxygen saturation (SctO2), peripheral oxygen saturation (SpO2), BIS values will record before the induction of anesthesia. Five minutes after the standard anesthesia induction all values will record and it will accept as a baseline. After that all these parameters will record in each 3 minutes until the beginning of surgery. Mean while, more than 5 % reduction in SctO2 and more than 20 % reduction in SctO2 and/or MAP will record. As well as, if the SctO2 reduces than 55 and 60 %, it will record.

• Study Type: Interventional
• Enrollment (Anticipated): 62
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey
  • Istanbul, Turkey, 34098
    • Ozlem Korkmaz Dilmen

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Diagnosis of infratentoril neoplasms

Exclusion Criteria: Stroke

• Diabetes mellitus
• Chronic obstructive pulmonary disease
• Anemia

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Factorial Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: The sitting; The sitting position Device sCtO2 Device BIS	Device: SctO2; The non invasive cerebral oxymetry (INVOS-Covidien) has been used to measure cerebral oxygen saturation.; Other Names: INVOS-Covidien; Device: BIS; Bispectral index
Active Comparator: The prone; The prone position Device sCtO2 Device BIS	Device: SctO2; The non invasive cerebral oxymetry (INVOS-Covidien) has been used to measure cerebral oxygen saturation.; Other Names: INVOS-Covidien; Device: BIS; Bispectral index

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cerebral oxygen saturation	After anesthesia induction cerebral oxygen saturation will record in each 3 minutes until the beginning of surgery	Change from baseline cerebral oxygen saturation up to skin incision

Collaborators and Investigators

• Sponsor: Istanbul University
• Investigators: Study Director: Ozlem Korkmaz Dilmen, Istanbul University Cerrahpasa School of Medicine, Istanbul, Turkey

Publications and helpful links

General Publications

• Dilmen OK, Akcil EF, Tureci E, Tunali Y, Bahar M, Tanriverdi T, Aydin S, Yentur E. Neurosurgery in the sitting position: retrospective analysis of 692 adult and pediatric cases. Turk Neurosurg. 2011;21(4):634-40.
• Pohl A, Cullen DJ. Cerebral ischemia during shoulder surgery in the upright position: a case series. J Clin Anesth. 2005 Sep;17(6):463-9. doi: 10.1016/j.jclinane.2004.09.012.
• Murphy GS, Szokol JW, Marymont JH, Greenberg SB, Avram MJ, Vender JS, Vaughn J, Nisman M. Cerebral oxygen desaturation events assessed by near-infrared spectroscopy during shoulder arthroscopy in the beach chair and lateral decubitus positions. Anesth Analg. 2010 Aug;111(2):496-505. doi: 10.1213/ANE.0b013e3181e33bd9. Epub 2010 May 27.

Study record dates

Study Major Dates

• Study Start: November 1, 2016
• Primary Completion (Anticipated): October 1, 2018
• Study Completion (Anticipated): October 1, 2018

Study Registration Dates

• First Submitted: October 10, 2016
• First Submitted That Met QC Criteria: October 13, 2016
• First Posted (Estimate): October 14, 2016

Study Record Updates

• Last Update Posted (Estimate): October 14, 2016
• Last Update Submitted That Met QC Criteria: October 13, 2016
• Last Verified: October 1, 2016

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neoplasms; Neoplasms by Site; Brain Neoplasms; Central Nervous System Neoplasms; Nervous System Neoplasms; Infratentorial Neoplasms
• Other Study ID Numbers: Istanbul

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes