"It's quite amazing. It's just like taking the lid off a monkey... & you just plonk it back on again."
Researcher describing sawing the skull of a marmoset

Surgery

At Cambridge University the experiments involved the marmosets being deliberately brain damaged by either sucking or cutting out areas of the brain or injecting toxins. Such invasive brain surgery would not only have a substantial negative effect on the monkey immediately after surgery, in terms of pain and distress, but also longer term effects resulting in physical and mental disabilities.

Their heads shaved, sliced open and then stitched up, leaving raw and bloody wounds, monkey after monkey made into mini Frankensteins.

Some of the surgery involved placing the monkey under anaesthetic, clamping the head in a frame, cutting open the scalp and scraping away the layer of muscles attached to the skull. An electric saw was then used to cut round the skull (one researcher described it as 'like taking a lid off') which was completely removed or left attached by a small piece of bone. With the brain exposed, a major brain artery was blocked. The skull was then replaced, the muscles glued back to it and the skin pulled back over and stitched.

In other experiments, some monkeys were used as control animals in 'sham' procedures; subjected to the surgery but not given brain damage. Others could be subjected to one, two or even three surgical brain procedures.

An additional surgical procedure for some monkeys involved minipumps (that released an experimental drug) being implanted and stitched under the skin at the back of the neck following brain damage. These pumps were surgically removed and replaced once a day over three days.

Telemetry probes were also implanted in the abdomen of some monkeys to record blood pressure and heart rate during testing. This also involved major surgery during which the transmitter was sewn and glued into place in the main abdominal artery.

Mishaps during surgery were sometimes reported. Records show: "Went down very badly. Lost a lot of blood from muscle which I cut in the old fashioned way by mistake. Suture not sticking very well."

"OK. Difficult to find fornix (a region of the brain). I think I was a bit too far forward. Am fairly confident I got it but probably did a bit extra damage."

Over recent years, a number of experimental monkeys died and others had to be killed. In 2000, at least two monkeys were so badly damaged during the implantation of the telemetry probe that they were partially paralysed and had to be killed.

Furthermore, records show that some attempts at surgery had to be abandoned because the monkeys were not sufficiently anaesthetised. In 2001, it was reported that one monkey called Carina actually woke up upon the first skin incision on the operating table. During that same year, it was reported that another attempt at surgery was not finished because a monkey called Inch had not gone under anaesthetic well.

During one surgical procedure, observed by the BUAV investigator, the conversation between the researchers suggests that the level of anaesthetic was not deep enough and the monkey was showing signs of coming round from the anaesthetic too early.

"I remember when he used to go to Tescos & get joints of meat & different things & he'd sit here practicing."
Researcher describing how another researcher practiced surgery

Post-Operative Care

The level of care and supervision that some monkeys received after surgery at Cambridge University was particularly concerning. The Code of Practice, states that: "Animals which are undergoing scientific procedures must be inspected at a frequency commensurate with the severity of the procedure." (Section 3.3)

Yet records show that some monkeys suffering the serious effects of severe brain damage were left unattended overnight - sometimes for up to 16 hours - with no monitoring.

For example, one incident involved a monkey called Agar who was found dead the day after surgery. Following brain damage, Agar's temperature fell and she was found to be breathing very fast. She was put in an incubator but was nevertheless still left for 15 hours overnight unattended, despite records showing that her temperature had only risen to 34.4°C by the end of the day. Normal daytime temperature for a marmoset is 38.6°C. By 8.30am the following morning Agar was dead.

Another monkey called Tonga used in the stroke research suffered greatly following brain damage. However, she was still left on her own for long periods overnight without monitoring.

On the morning of 10/1/02, after having been left for almost 16 hours, Tonga's body temperature had plummeted to 31.1°C.

Other examples included one monkey called Randall who was operated on on the 31/7/01. The last entry on his post-op sheet for that day at 5.50pm states "Head a bit bloody, awake but drowsy". Yet Randall was subsequently left overnight for 15 hours. Another monkey, called Shazney, was also left overnight even though the last entry on her post-op sheet states "Some bleeding from head wound. Cleaned."

Reports show that some surgery did not finish until late afternoon/early evening but some monkeys were then monitored for less than two hours following the end of surgery before being left alone for the night.

On another occasion, surgery on a monkey called Turks was not completed until 7pm. However, records show that when the researcher left at 2am the following morning, the monkey was left on her own without having re-gained consciousness.

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