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TissueDB/Simulators/Grapefruit Distal Anterior Cerebral Artery Bypass Simulator

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General Information

A pink grapefruit shown whole, halved, and in segments
A pink grapefruit shown whole, halved, and in segments. In this model the grapefruit simulates the brain: its flesh stands in for the cerebral cortex, its rind and pith for the skin and subcutaneous tissue, and its inner skin for the arachnoid and pia mater. Two longitudinal pole-to-pole rind incisions open a cavity — the interhemispheric fissure — in which two vessels are anastomosed side-to-side. Image: Wikimedia Commons, CC BY-SA 2.5 (not from the source paper).

This simulator trains side-to-side distal anterior cerebral artery (dACA) bypass — a deep, narrow-field microvascular anastomosis — using a grapefruit and a pair of small vessels. A large grapefruit is cut with two pole-to-pole rind incisions to open a cavity between its sections that recreates the interhemispheric fissure; the working depth from rind to central column is about 4 cm, matching the cadaveric distance from the cerebral cortex to the corpus callosum. Two vessels — chicken wing brachial arteries or thin synthetic tubing — are cannulated, laid parallel in the central column, and joined side-to-side with 10‑0 nylon under microscope magnification. A small aquarium pump drives about 250 mL of dyed water through the vessels in a closed loop, so any leak in the anastomosis is immediately visible. The model needs no special facilities and can be built from locally available materials.[1]

Field Details
General Information Low-cost cerebrovascular bypass training model from Cikla et al., World Neurosurgery 2020. The grapefruit recreates both the deep, narrow operative field of the interhemispheric fissure and the tissues lining it — flesh as cortex, rind and pith as skin and subcutaneous tissue, inner skin as the arachnoid and pia mater. Vessels can be biologic (chicken wing brachial artery, closer tactile feel) or synthetic (thin tubing, faster and reusable); with synthetic vessels the model carries no infection risk and can even be used inside an operating room.[1]
Features and Basic Operation A closed water circuit gives the model active perfusion: a submersible aquarium pump (80 GPH) pushes about 250 mL of dyed water from a one-litre reservoir through an afferent nasal cannula that splits into the two vessels at the grapefruit's ventral pole, and an efferent cannula returns the water from the dorsal pole to the reservoir. Dye makes any anastomotic leak visible, which is the model's built-in feedback. The grapefruit's sections retract on small stays so the trainee practises opening and holding the interhemispheric fissure, and the depth to the central column (about 4 cm) reproduces the constraints of real dACA bypass. Vessels can be swapped between biologic chicken wing and synthetic tubing without changing the main build.[1]
Current Development Status Assessed by 12 board-certified neurosurgeons across two training courses, who rated it above a basic anastomosis training kit and a chicken-wing model for realism, challenge and skill transfer; not tested in live surgery.[1]
Estimated Build Time and Cost About 5–10 minutes to prepare the grapefruit; chicken-wing vessels add about 10 minutes.[1], About US$2–US$29 per training; reusable parts under US$20 (2020 US prices).[1]
Specialized Tools and Equipment An operating microscope or high-magnification surgical loupes for the anastomosis; a microsurgical instrument set (needle holder, jeweller's forceps and microscissors) for the 10‑0 suturing; a No. 11 scalpel for the rind incisions; scissors and tweezers to remove the chicken-wing skin and harvest the artery; forceps to remove the grapefruit stem; small retractors and small elastic stays to open and hold the grapefruit sections; and a temporary aneurysm-clip applier with mini titanium clips (the source used a Sugita T2 Titanium Clip System, Mizuho America) to occlude the vessels during suturing. Surgical instruments must be washed immediately after each session, because the acidic grapefruit juice corrodes them.[1]
Version Not stated in source
Development Team Contact Information Developed by Ulas Cikla, Paul Rowley, Erik L. Jennings Simoes, Burak Ozaydin, Steven L. Goodman and Mustafa K. Baskaya (Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA), Nirav J. Patel (Neurosurgery, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA) and Emel Avci (Neurological Surgery, Mersin University, Mersin, Turkey). Corresponding author: Mustafa K. Baskaya (baskaya@neurosurgery.wisc.edu).[1]

Tissues

Tissue Qty Material Cost Notes
Cerebral cortex, scalp and meninges 1 Grapefruit US$1 The flesh behaves like the cerebral cortex (tearing if nicked, like cortex), the rind and pith like skin and subcutaneous tissue, and the inner skin like the arachnoid and pia mater. A large fruit (12–15 cm) gives a rind-to-central-column depth of about 4 cm, matching the cadaveric cortex-to-corpus-callosum distance.[1]
Cerebral artery (pericallosal branches of the distal ACA) 2 Chicken wing brachial artery, or synthetic tubing US$1 per wing Donor and recipient vessels for the side-to-side anastomosis, with a feel and dimensions similar to cerebral arteries; one chicken wing yields both 5–6 cm segments. Self-cannulated 2 mm synthetic tubing is the reusable alternative when fresh chicken wing is unavailable — faster to prepare, at a higher per-training cost.[1]


Structural Parts

Part Name Qty Material Cost Notes
Reservoir, 1 litre 1 Beaker, bowl or jar — Holds about 250 mL of dyed water; the submerged pump and the returning water sit here. Bench stock.[1]
Aquarium pump 1 Submersible aquarium pump, 80 GPH (about 300 L/h) US$8 Drives the closed water loop; submerged in the reservoir and connected to the afferent nasal cannula by its own outlet tubing. The source used a VicTsing 80 GPH pump.[1]
Nasal cannula 2 Adult nasal cannula (source used Medline Adult Soft-Touch) US$4 (US$2 each) The afferent cannula splits into two channels entering the ventral pole (the right and left ACA supply); the efferent cannula returns water from the dorsal pole to the reservoir.[1]
Cannulation stubs 4 Micropipette tips (IV angiocatheters are an alternative) about US$0.06 Short stubs fitted to each vessel end so the vessels connect to the cannulas; tied on with 3‑0 nylon.[1]
Stabilising base 1 Repurposed Styrofoam, a tray, a bowl, or a roll of duct tape — Holds the grapefruit with the fissure facing the table so the trainee works from the opposite side. Bench stock; the source lists these as equivalent supports.[1]
Red food colouring Trace Water-soluble dye — Added to the reservoir water so any leak from the anastomosis is visible. Bench stock.[1]
10‑0 nylon suture 1 pack 10‑0 nylon monofilament on a microsurgical needle — The side-to-side anastomosis suture. Bench stock.[1]
3‑0 nylon suture 1 pack 3‑0 nylon — Ties each vessel end onto its cannulation stub. Bench stock.[1]


Build Instructions

Build sequence from Cikla et al. (2020) Materials and Methods.

Phase 1: Prepare the grapefruit

  1. Choose a large grapefruit (12–15 cm diameter) and rest it on the stabilising base.[1]
  2. Make two parallel pole-to-pole incisions in the rind with a No. 11 scalpel, axis to axis, marking off a region covering about one-fifth of the surface.[1]
  3. Cut along both lines down to the border between pith and skin only — do not cut into the flesh.[1]
  4. Slice one of the two marked rind strips lengthways to make a strip about 2 cm wide, and set it aside for Phase 2.[1]
  5. Dissect bluntly along the natural groove between the two grapefruit sections to open the cavity that represents the interhemispheric fissure.[1]

Verification: the cavity opens cleanly to the central column without tearing the flesh.

Phase 2: Prepare and place the vessels

  1. Remove the skin from a chicken wing and harvest the brachial artery as a 5–6 cm segment (for biologic vessels); strip the adventitia about 1 mm from each end.[2][1]
  2. Fit each vessel end over a 2.5 cm angiocatheter (or micropipette) tip and tie it on with 3‑0 nylon. Prepare a second matched vessel from the same wing. Self-cannulated 2 mm synthetic tubing can be used instead.[1]
  3. Lay the two vessels parallel in the central column of the grapefruit.[1]
  4. Replace the 2 cm rind strip from Phase 1 over the vessels with its pith side facing them, forming a buried floor.[1]

Verification: the two vessels sit parallel and accessible in the central column.

Phase 3: Assemble the water circuit

  1. Connect the vessels to two nasal cannulas: the ventral-pole cannula splits into two afferent channels (one per vessel), the dorsal-pole cannula takes the two efferent channels.[1]
  2. Fill the one-litre reservoir with about 250 mL of water and red dye and submerge the aquarium pump in it. Run the pump's outlet tubing to the afferent cannula and turn it on to confirm a closed circulating loop. The recirculation method follows the previously described Wisconsin model.[3][1]

Verification: water circulates through both vessels in a closed loop with no leak before practice begins.

Phase 4: Bypass practice

  1. Steady the grapefruit on its base with the fissure facing the table, and retract the sections on small elastic stays to expose the vessels about 4 cm down.[1]
  2. Place a temporary aneurysm clip proximal and distal to the planned bypass on each vessel to stop the flow.[1]
  3. Incise each occluded vessel along the bypass markings and join the two vessels side-to-side with 10‑0 nylon under the microscope.[1]
  4. Remove the clips and watch the suture line under circulation: leaking dyed water means the anastomosis needs further sutures until it runs dry.[1]

Verification: with the clips off, water flows through both vessels and the anastomosis holds without leaking into the surrounding flesh.

Reset between learners

  • Remove the clips, check the anastomosis for leaks and add sutures until dry.[1]
  • Disconnect the vessels and discard used chicken-wing segments; reusable synthetic tubing can be kept.[1]
  • Wash all instruments immediately — the acidic grapefruit juice corrodes them.[1]
  • Refresh the reservoir water, and replace the grapefruit when its flesh is too damaged to retract without tearing.[1]

Not suitable for

  • Procedures other than deep-field microvascular anastomosis — the model reproduces the dACA bypass field specifically.[1]
  • Training that needs true blood behaviour or thrombosis — the circuit uses water, which the authors note reduces perfusion realism and does not model clotting.[1]



References

[1][2][3]

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 1.21 1.22 1.23 1.24 1.25 1.26 1.27 1.28 1.29 1.30 1.31 1.32 1.33 1.34 1.35 1.36 1.37 1.38 1.39 Cikla U, Rowley P, Jennings Simoes EL, Ozaydin B, Goodman SL, Avci E, Baskaya MK, Patel NJ. "Grapefruit Training Model for Distal Anterior Cerebral Artery Side-to-Side Bypass." World Neurosurgery. 2020;138:39–51. DOI: 10.1016/j.wneu.2020.02.107. PMID: 32109640.
  2. ↑ 2.0 2.1 Hino A, Batjer HH, Schackert G, et al. "Training in microvascular surgery using a chicken wing artery." Neurosurgery. 2003;52:1495–1498. (Chicken wing brachial artery harvesting method; Ref 9 of Cikla 2020.)
  3. ↑ 3.0 3.1 Cikla U, Sahin B, Hanalioglu S, Ahmed AS, Niemann D, Baskaya MK. "A novel, low-cost, reusable, high-fidelity neurosurgical training simulator for cerebrovascular bypass surgery." J Neurosurg. 2018:1–9. (Wisconsin Model; closed-circulation method and validation-rubric precedent, Ref 10 of Cikla 2020.)



Simulator data
Alternative names grapefruit model
grapefruit bypass model
grapefruit dACA bypass model



Page data
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Authors Arturopelayo
License CC-BY-SA-4.0
Language English (en)
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Created April 12, 2026 by Arturo Pelayo
Last edit June 2, 2026 by Arturo Pelayo
Cite as Arturopelayo (2026). "TissueDB/Simulators/Grapefruit Distal Anterior Cerebral Artery Bypass Simulator". Appropedia. Retrieved June 4, 2026.
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