Swiss Prospective Autologous Bone Flap Resorption Study (SPARS)

The complications after reimplantation of cryoconserved autologous bone flaps are reported inhomogeniously in the literature. Especially the incidence of bone flap resorption varies from 0% to about 30%. More recent retrospective studies seem to find higher resorption rates and thus suggest to implant artificial bone replacements from the start. The Swiss Prospective Autologous bone Resorption Study is the first propspective observational study designed to determine the true incidence of autologous bone resorption.

Study Overview

• Status: Terminated
• Conditions: Brain Edema
• Intervention / Treatment: Procedure: Reimplantation of cryoconserved bone flap

Detailed Description

Patients undergoing decompressive craniectomy and delayed reimplantation of the cryoconserved autologous bone flap are included in a clinical and image-based follow-up to identify cases and severity of bone flap resorption.

The explanted autologous bone flaps are cryoconserved and reimplanted at a time-point defined by the surgeon according to standards of the participating hospital. The fixation of the bone flap is also performed according to the surgeon's decision.

A cranial CT is performed within one week after reimplantation to define a baseline.

A second, only clinical, follow-up will take place within 2 months after reimplantation.

Two more follow-ups including photodocumentation of the cranial and facial symmetry (portrait and profile) and cranial CT will take place 12 and 24 months after reimplantation.

The indication for surgical revision in case of bone flap resorption is independent from the study and falls under the responsibility of the treating surgeon.

• Study Type: Observational
• Enrollment (Actual): 88

Contacts and Locations

Study Locations

• Switzerland
  • Bern, Switzerland, 3010
    • Inselspital Bern
  • Zurich, Switzerland, 8091
    • Dept. of Neurosurgery, Zurich University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 99 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

All patients undergoing reimplantation of cryoconserved bone flaps after craniectomy

Description

Inclusion Criteria:

• all patients after hemicraniectomy or bifrontal craniectomy
• age 18-99 y/o
• ability to understand and sign informed consent (alternatively, legal representative may sign)

Exclusion Criteria:

• bone flap not fit for reimplantation
• no cryoconservation performed but other technique
• pregnancy
• patient's death

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Reimplantation of cryoconserved bone flap; All patients who receive reimplantation of a cryoconserved autologous bone flap	Procedure: Reimplantation of cryoconserved bone flap; A bone flap, which was explanted for decompression of a swollen brain or following severe head trauma and which was cryoconserved in the meantime is reimplanted. This procedure is the gold-standard therapy after decompressive hemicraniectomy and is routinely performed.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of a relevant bone resorption within 12 months after reimplantation	The extent of bone flap resorption is analyzed as well objectivela as subjectivels: objective criteria: Volumetric reconstruction of the bone flap from the CT scans and subtration of the actual bone flap volume from the 3D model at the basline-timepoint directly after reimplantation subjective: a bone flap resorption score is validated	12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of an indication for surgical revision	The indication for a surgical revision falls under responsibility of the treating surgeon.	12 and 24 months after reimplantation
Death	death	2, 12 and 24 months after reimplantation
Infections	Infections	2, 12 and 24 months after reimplantation
Fluid collections and bleedings	subgaleal, epidural and subdural fluid collections and hematomas	2, 12 and 24 months after reimplantation
Hydrocephalus	hydrocephalus	2, 12 and 24 months after reimplantation
Temporal muscle atrophy	temporal muscle atrophy	2, 12 and 24 months after reimplantation
timepoint between explantation and reimplantation	measured in months	2, 12 and 24 months after reimplantation
patient age	in years	2, 12 and 24 months after reimplantation
fragmentation of the bone flap	in number of pieces	2, 12 and 24 months after reimplantation
temperature used for cryoconservation	in °C	2, 12 and 24 months after reimplantation
pathologies leading to explantation of the bone flap (hemicraniectomy)	trauma, tumor, stroke and others	2, 12 and 24 months after reimplantation

Collaborators and Investigators

• Sponsor: University of Zurich

Study record dates

Study Major Dates

• Study Start: January 1, 2015
• Primary Completion (Actual): December 31, 2023
• Study Completion (Actual): December 31, 2023

Study Registration Dates

• First Submitted: December 10, 2014
• First Submitted That Met QC Criteria: December 15, 2014
• First Posted (Estimated): December 19, 2014

Study Record Updates

• Last Update Posted (Actual): May 14, 2024
• Last Update Submitted That Met QC Criteria: May 12, 2024
• Last Verified: May 1, 2024

More Information

Terms related to this study

• Keywords: bone resorption; decompressive craniectomy; patient specific implant; autologous bone flap; malignant brain swelling; aseptic bone necrosis
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Brain Edema
• Other Study ID Numbers: ZH-2014-0370