Purpose
To provide a uniform grading system to assess and minimize the risk of surgical and post-surgical complications in non-human primates undergoing multiple abdominal surgeries.
Definitions
- Laparotomy:
- A surgical incision into the abdominal cavity.
- Laparoscopy:
- A type of laparotomy that involves small incisions and the aid of a camera.
- Resection:
- The surgical removal of part or all of a tissue, structure, or organ.
Background
Penetration of the abdominal cavity and collection of tissue can provide critical scientific information¹. Abdominal survival surgery has been conducted successfully in healthy macaques². However, abdominal surgery often results in the development of peritoneal adhesions. Up to 93% of people who have abdominal surgery develop post-surgical peritoneal adhesions³. Although typically asymptomatic in people, adhesions can lead to small intestinal obstruction in people, abdominal pain, or nausea4. These can be difficult signs to evaluate in non-human animals.
Although less invasive, laparoscopic procedures still carry a risk for adhesion formation after repeat surgical procedures5. When scientifically justified and approved by IACUC, serial laparoscopic abdominal surgeries may be performed in some animals. To assess and minimize the risk of surgical and post-surgical complications in individual non-human primates undergoing multiple abdominal surgeries, this policy outlines an adhesion grading system for serial abdominal surgeries in non-human primates.
Policy
Prior to performing abdominal surgery, every non-human primate must undergo a pre-surgical examination by a WaNPRC clinical veterinarian. Only animals deemed clinically stable may proceed with surgery.
At the initiation (prior to surgical manipulation) of any repeat survival abdominal surgery in a non-human primate, the degree of peritoneal adhesions will be graded by the WaNPRC surgeon (or designee) according to a modified Zühlke’s grading system6 shown in the table below. The location of the adhesion should be noted along with the score. The surgeon will approach the surgery as normally performed and should not extensively handle abdominal contents in order to provide a score, but will provide a score based on what is noted during the standard surgical approach.
| Adhesion Size/Extent | |||
| <1 cm2 | 1-3 cm2 | >3 cm2 | |
| No adhesions – Score 0 | N/A | N/A | N/A |
| Filmy adhesions: easy to separate by blunt dissection; no vascularization. | 1 | 2 | 3 |
| Stronger adhesions: blunt dissection possible with effort; sharp dissection may be preferred (beginning of vascularization) | 2 | 4 | 6 |
| Strong adhesions: separation possible by sharp dissection only; clear vascularization | 3 | 6 | 9 |
| Very strong adhesions: separation possible by sharp dissection only (organ strongly attached with severe adhesions and damage of organs hardly preventable) | 4 | 8 | 12 |
If multiple adhesions are noted, the score is the sum of all individual adhesion scores. When stronger, strong, or very strong adhesions are present in the target area of the intended surgery, a WaNPRC veterinarian must be consulted before progressing to determine if surgery can safely be performed.
If Score <7 and adhesions are not within the target area, surgery can proceed, and the animal can undergo future abdominal survival surgeries if approved in the associated IACUC protocol.
If Score 7-10 and adhesions are not within the target area, surgery can proceed, but the animal cannot undergo future abdominal survival surgeries
If score ≥10: Survival surgery cannot proceed and a WaNPRC veterinarian must be consulted. The veterinarian may advise that the surgery be performed as a terminal procedure, that the abdomen be closed without further surgery, or that the animal be euthanized without further experimental manipulation.
References
- Mohan M, Kaushal D, Aye P, et al. Focused examination of the intestinal lamina propria yields greater molecular insight into mechanisms underlying SIV induced immune dysfunction. PLoS ONE (2012) 7(4): e34561
- Edghill-Smith YY, Aldrich K, Zhao J et al. Effects of intestinal survival surgery on systemic and mucosal immune responses in SIV-infected rhesus macaques. J Med Primatol (2002) 31: 313-322
- Menzies D, Ellis H. Intestinal obstruction from adhesions – how big is the problem? Ann R Coll Surg Engl (1990) 72: 60-63
- Catena F, Di Saverio S, Coccolini F, et al. Adhesive small bowel adhesions obstruction: Evolutions in diagnosis, management and prevention. World J Gastrointest Surg (2016) 8(3):222-231
- Diamond MP, Freeman ML, Clinical implications of postsurgical adhesions. Human Reproduction Update (2001) 7(6): 567-5765.
- Zühlke HV, Lorenz EM, Straub EM et al, Pathophysiology and classification of adhesions. Langenbecks Arch Chir Suppl II Verh Dtsch Ges Chir (1990) 345: 1009–16
Approval/Review Dates
Originally Approved: 10/20/2016
Last Reviewed/Revised by the IACUC: 05/18/2023