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Office of Animal Welfare

​Neuroscience Studies in Non-Human Primates

Purpose

To define the process for requesting repair surgeries for non-human primates enrolled in neuroscience studies.

Definitions

Surgery:
A procedure performed using instruments on a living body that involves incision, excision, or suturing, with the exception of cleaning and cranial chamber debridement.
Repair Surgery:
A repair surgery is a surgery done to make surgical revisions associated with an implanted device in order to further the goals of the research. For example, a repair surgery could involve replacing an implanted device that is no longer sending a signal, stabilization of an existing device, expansion of a craniotomy, or removal of a device. IACUC approval is required for repair surgeries.
Clinical Surgery:
A clinical surgery is one needed to protect the health of the animal and directed to be performed by the clinical veterinarian involved in the care of the animal. The veterinary or research staff may perform the surgery, at the discretion of the veterinarian involved. IACUC approval is not required for clinical surgeries.​

Background

Neuroscience studies involving non-human primates often involve multiple major survival surgeries to create the appropriate animal model. Unanticipated events such as implant failure, damage or rejection may require animals to have additional, unplanned surgeries to repair or replace devices or hardware. Anticipating potential consequences of an implant failure before it occurs is crucial for animal well-being continuation of the study.

According to the Guide for the Care and Use of Mammals in Neuroscience and Behavioral Research1, “Unambiguous experimental endpoints should be established before any devices or hardware are implanted. These endpoints should indicate when devices or hardware should be removed because of failure, infection, or inflammation. Successful re-implantation after implant failure may be possible in some circumstances. Therefore, the necessary conditions for re-implantation of previously used or replacement hardware should be described in the animal use protocol and approved by the IACUC. Anticipating the potential consequences of implant failure before its occurrence is crucial for the viability of the study and animal well-being. A team approach involving veterinary staff, caretakers, neuroscientists, and technicians is critical to the long-term success of experiments that use animals with chronic implants.”

Policy

The IACUC protocol must describe all surgeries necessary to create the planned model. If more than one surgery is required to create the model, the scientific or animal welfare justification must be included.

The IACUC recognizes that unanticipated events requiring surgery may occur. As such, the protocol should include provision for one or two surgeries in the event that a repair is needed.

All additional repair surgeries require review and approval by the IACUC. Since additional surgeries would be a result of unpredictable events, researchers may submit a request for additional surgeries before the repair surgery becomes necessary, providing the animal with a “banked” repair. Failure to obtain this approval means that an animal cannot have additional experimental surgeries until IACUC approval is obtained. Up to two repair surgeries can be requested at one time. The request for approval must include the following:

  1. justification for the scientific need for continuation of the animal on the study.
  2. a complete medical history of surgeries already conducted on the animal, including both experimental and clinical surgeries (including the surgery prompting the request even if it has not yet occurred).

Requests for additional repair surgeries must be submitted as Amendments and should include ‘Repair Surgery Request’ in the short title. As always, any IACUC member who has concerns about a requested repair surgery has the option to call for FCR while the amendment is under review.

Procedures that do not require IACUC approval for each event

Recording chamber debridement:

Maintenance of cranial implants requires frequent cleaning as well as less frequent recording chamber debridement. Debridement involves removing tissue in an existing craniotomy that impedes or obstructs the placement of transdural electrodes or guide tubes (which carry the electrodes to the brain parenchyma) under anesthesia. The procedure is required at different intervals (weekly to monthly or even less frequently) for different animals, depending on the type of electrode and guide tube, the depth of the targeted neural structures and consideration of the superficial cortex in the chamber. Granulation tissue, scar tissue, mineralized fibrotic tissue and bone spurs from the edge of the craniotomy are removed.

Cranial chamber debridement is considered a necessary maintenance procedure and does not require IACUC approval for each debridement, though these procedures must be included in the approved protocol.

Cranial chamber debridement does not include:

  1. extension of a craniotomy beyond its original margin
  2. relocation of the recording chamber
  3. a new craniotomy or an extension of an existing craniotomy past the confines of the original
  4. placement of cranial bone screws to place a chamber, or
  5. placement (or replacement) of cranial bone screws to re-anchor a recording chamber over an existing craniotomy.

​Non-surgical hardware or electrode repair:

Implants may be complex devices, including sophisticated electronics, wires and connectors. Sometimes an animal must be sedated or anesthetized to allow for repositioning or repair of the implant without any surgical manipulation of the animal. These procedures are performed infrequently, and should not require more than one sedation/anesthesia event within a 7-day period.

Non-surgical hardware or electrode repair does not require IACUC approval for each event, though these procedures must be included in the approved protocol.

Non-surgical hardware or electrode repair does not include:

  1. incision of skin, muscle, or other tissue
  2. placement of bone screws, or
  3. placement of sutures in tissue

References

  1. National Research Council (U.S.). Committee on Guidelines for the Use of Animals in Neuroscience and Behavioral Research & Institute for Laboratory Animal Research (U.S.). Guide for the Care and Use of Mammals in Neuroscience and Behavioral Research, (National Academies Press, Washington, D.C., 2003).​​

Approval/Review Dates

Originally A​​​pproved: 11/15/2007
Last Reviewed/Revised by the IACUC: 03/17/2022


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