What Happened?

A student sustained a laceration to his index finger while cutting human tissue with a scalpel. The student had planned to collect tissue slices from previously frozen spinal cord tissue for homogenization. During sectioning, the scalpel blade became lodged in the tissue. While stabilizing the sample with his fingers, the student pulled on the scalpel to free it; the blade released suddenly and lacerated their index finger. They immediately washed their hand with soap and water, notified their supervisor, and reported to Occupational Health and Safety for medical evaluation.

What Was The Cause?

• Immediate cause: A scalpel blade lodged in frozen spinal cord tissue released suddenly when the student pulled it free, lacerating the stabilizing fingers held in the blade's release path.
• Underlying causes:
  • Stabilizing fingers were positioned in the line of fire of the blade.
  • Bare fingers, rather than forceps or another secondary tool, were used to hold the sample.
  • The wedged-blade release mechanism was not recognized as a distinct hazard requiring a different technique (stop and reposition, rather than pull harder).
  • Cut-resistant gloves were not worn on the stabilizing hand.
• Root cause: Gap in the lab's SOP and training for hand-held sectioning of frozen tissue — specifically, failure to specify safe hand positioning (stabilizing hand outside the blade path), use of secondary tools (forceps, hemostats) to keep hands out of the line of fire, cut-resistant PPE for the non-dominant hand, and a defined response to wedged-blade situations (stop, reposition, change blade — do not pull harder).

How Can Incidents Like This Be Prevented?

• Consider the right tool for cutting:
  • Use a cryostat for producing tissue slices where feasible, eliminating hand-held blade work entirely.
  • Never use a scalpel blade without a handle.
  • Consider using a dermal punch instead of a scalpel.
• Develop or revise the SOP for hand-held sectioning of frozen tissue to specify:
  • Cut away from the body and from the stabilizing hand.
  • Use a stabilizing tool, such as forcepts; never use your fingers.
  • If the blade becomes wedged, stop. Do not pull harder. Release pressure, reposition the sample, or discard the blade and start with a fresh one. Name this as a defined stop-work trigger.
  • Change blades frequently; discard dulled blades into a sharps container.
• Require a documented SOP walkthrough and supervised first performance before independent sectioning work.
• Train explicitly on line-of-fire awareness — the principle that hands, fingers, and body parts should never be positioned in the path a tool or workpiece would travel if it moved unexpectedly. Use this incident as a case example.
• Train explicitly on wedged-tool/stored-energy release — the principle that applying force to a stuck tool stores energy that is suddenly released; the correct response is to reduce force and reposition, not to pull harder.

Resources

• Risk Group Classification for Infectious Agents
• Pathogen Safety Data Sheets