Tortoise Bladder Stones (Uroliths)

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One of the more interesting and unique surgeries we perform is the removal of a bladder stone (called a cystotomy) from California Desert Tortoises, and various other tortoise species like African spurred tortoises (sulfates) and leopard tortoises. It is usually a problem in captive tortoises, but it has been diagnosed in wildl tortoises on occasion. The stones tend to be smaller in wild tortoises.

Some of these stones grow to tremendous size, and it is a wonder that these animals can survive with such a problem. Other animal species get bladder stones, but none of them are anywhere near as large as tortoise bladder stones.

Don’t miss the video of the beating heart at the end of this page.

This page contains graphic surgical pictures.


Physiology

The normal waste product for protein metabolism is ammonia. Tortoises convert thisi ammonia to uric acid, which is less toxic to the bladder wall and lets them hold water in their bladder for long periods of time. Tortoises are a desert species, so water conservation is a large part of their physiology as they have adpated to their arid environment. They can recycle water from their bladder into their system when they do not have access to drinking water.

If the uric acid builds up in high enough levels, a situation that might happen if the tortoise is not drinking and staying well hydrated, the uric acids combines with electrolytes like sodium, calcium, and potassium, to form urates. In a well hydrated tortoise these urates are secreted normally when urinating. In a dehydrated tortoise that is recycling its urine the urates are not secreted, and can slowly build up into a bladder stone.

When we analyze tortoise bladder stones chemically they are comprised almost exclusively of urates.

Cause

The exact cause is unknown. Dehydration plays a significant factor in this disease. Many people believe that tortoises get all the water they need from their food. This is not true, they need to drink water also, so make sure fresh water is available all day and also periodic soaking is recommended. Use lukewarm water, make sure the water level is no higher than the beginning of the top shell (carapace), and soak for up to 10 minutes. Dry your tortoise off before placing back in its normal environment. Do not soak if your tortoise has surgery unless confirmed by your veterinarian.

Diet is also a factor in this disease. For all tortoises the overwhelming majority of their diet is from plants. If the diet is too high in protein, which would be from feeding dog or cat food, there might be excess urate production, leading to an increased chance of a bladder stone being formed. Your tortoise’s diet should consist of a high percentage of grass and a lesser amount of green, lelafy vegetables.

Symptoms

There are no specific symptoms that tell us a tortoise has a bladder stone, and some of them don’t show any symptoms at all. The more common symptoms are nasal discharge, poor appetite, straining to have a bowel movement, inability to lay eggs, lameness in back legs, and lethargy. A tortoise can become paralyzed in the back legs due to mechanical pressure from the bladder stone, and the problem can even progress further and some tortoises can succumb to the bladder stone.

Some of these stones are diagnosed as incidental findings when we take an x-ray or perform an exam for an unrelated problem. The tremendous size of some of the stones indicates they may have been present for years before being diagnosed. Anybody that has ever had a kidney stone can sympathize with what these animals feel like with such large stones.

Diagnosis

There are two methods utilized to diagnose bladder stones. During an examination we can sometimes palpate a stone by gently rolling the tortoise back and forth while we feel in the soft spot by its rear leg.

To perform the palpation technique you need to understand tortoise anatomy and be experienced at palpation.

Some tortoise bladder stones are small land can be removal via the pre femoral approach. It is performed in the same area as the palpation picture above

 

Not every stone can be found on palpation. The other method to make a diagnosis, and usually more reliable method, is to take an x-ray. Even though the stone in this x-ray is large, this is not an unusual finding. Some of the stones are so large that we have to break them into pieces to get them out of the opening in the shell.

You can see the actual size of this stone measure in cm. It takes 2.5 cm to make up an inch.

Surgical Procedure

The usual treatment for a bladder stone in tortoises is to perform surgery to completely remove the stone. In this surgery we literally cut a hole in the bottom of the shell and remove the stone from the bladder. Most tortoises do fine postoperatively, and after a few days in the hospital and a few weeks of recuperation at home, they are back to normal. We tend not to perform this surgery when hibernation is near.

Prior to surgery our patient is prepared to minimize anesthetic risk. In some patients we place a feeding tube to insure adequate hydration and nutrition, both before and after the surgery. In other patients we insert an intravenous catheter (IV) to maintain blood pressure during surgery.

This tortoise has an IV catheter in its jugulare vein. We use this vein because it is relatively easy to insert the catheter and it is large enough to take the volume of fluid we need to give.

Once the tortoise is stable and ready for surgery we gently induce anesthesia with a mask.

When fully relaxed we gently inserted a breathing tub called an endotracheal tube (ET). This facilitates the administration of oxygen and anesthesia in a much more efficient manner.

 After the tortoise is anesthetized the bottom of the shell (called the plastron) is cleansed thoroughly. This may take several scrubbings with the use of a gentle brush to get clean enough for surgery.

Our surgeon prepares for this surgery simultaneously

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While our patient is being prepared Dr. Ridgeway is preparing his instruments

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A sterile dremel is used to cut into the shell

When the shell is clean our surgeon carefully commences the draping process. This is important to prevent contamination and infection. Infection is especially critical in this surgery because once the cut piece of shell is resealed to the bottom of the shell, an infection can fester on the inside without our knowing about it.

Our patient is prepped and ready to get this huge stone out of its bladder

The rest of the surgical team is preparing at the same time. These assistants are students in our externship program. They will be assisting the surgeon with flushing and suctioning of fluids, along with the administration of anesthesia.

Even though it is living tissue, which means it has feeling and bleeds, tortoise shells are tough. We use a special drill called a dremel to cut the shell. We have gone through many of them over the years!

This close up view shows the serrated edge. They wear down fast trying to cut through the tough (but living) shell.

Dr. Ridgeway starts his cut with his safety glasses on to protect him from particles brought on by the drill used to cut into the shell.

The blade spins at a high speed so sterile water needs to be constantly applied to the cut surface to minimize burning. The blade cuts at an angle facilitating replacement of the shell when the surgery is complete. If this angled cut is not made, the shell will just fall back into the abdominal cavity (it is called the coelomic cavity in a reptile) and the incision site will never heal.

The speed means you need to wear goggles  (and also keep the camera lens out of the line of spray)! Shell is living tissue which is why you see blood in this picture.

We have a short Quicktime video of this part of the surgery. Click on the link below to start it.

Dremel in use

When the shell has been cut in a rectangular piece it is gently pried up with an instrument called an elevator. There are muscular attachments that are gently separated from the shell to allow the shell to become completely free.

The rectangular piece of cut shell is removed and placed inside saline soaked gauze until it is put back at the end of the surgery. The cut shell is living tissue and needs careful handling. After it is removed it is kept moist with sterile saline until it is replaced at the end of the surgery.

A close up of the edge of the shell that was cut by the dremel. It is made up of a extensive blood supply with calcium, phosphorous, and a protein matrix. Since reptiles (ectothermic animals) have a slow metabolism in can take up to 2 years for the cut shell to completely heal.

The next layer encountered is the lining of the coelomic cavity. It is gently cut to give full exposure to the organs in the cavity.

Internal organs can be visualized easily through this large opening. These are egg follicles.

Before we proceed further fluids in the coelomic cavity are suctioned out for better visualization

The bladder is gently exteriorized through the hole in the shell

This stone was too large to fit the opening so the lining of the coelomic cavity had to be enlarged. For faster healing me make this opening just large enough to gently squeeze the bladder out of the cavity with the stone still inside the bladder.

Using instruments and gently traction the offending bladder finally gives up and out it comes

When fully exteriorized it is packed off so no debris falls back into the coelomic cavity

Before actual stone removal a “stay” suture is placed in the bladder at two locations. The suture is then attached to a hemostat and clamped to the towels. This prevents the bladder from falling back into the coelomic cavity when the stone is removed.

Dr. Ridgeway has made an incision into the bladder and the stone is starting to bulge out

Here is the culprit as it is being removed from the bladder. Can you imagine what this would feel like inside of you?

On occasion we encounter a stone that is so large it needs to be cut in half to be able to fit out of the opening in the shell

This was the worst stone we have ever seen!

It was huge and in many fragments. It is the same stone in the radiograph at the beginning of this page

Once we removed the large pieces there were hundreds of small fragments lining the bladder. They can be the basis for stone reformation.

We flush the bladder with saline and suction them out

Only when all stone fragments are removed do we suture up the bladder

It took almost 30 minutes to remove all the large pieces and fragments. They weighed .8 kg, almost 2 pounds!

The bladder is sometimes filled with a sludge like material. If the sludge is not removed healing will be delayed and the potential for recurrence of the stone increases. The larger clumps of sludge are removed with a special instrument called an angle spoon. This high tech instrument is made special in our lab by taking a regular tablespoon and bending it.

The smaller pieces are suctioned after the bladder has been flushed. This usually takes many flushings with sterile saline. Only when the bladder has been thoroughly flushed is it sutured back together. Notice how inflamed the inner lining of the bladder has become from the tremendous irritation from the stone. This bladder is also thickened for the same reason. A normal bladder is very thin walled, almost like tissue paper.

A special suture material is used to close the opening in the bladder. This suture is very strong yet causes minimal tissue reaction, and will slowly dissolve over several months.

The coelomic cavity is also flushed copiously with warm sterile saline, then the fluid is suctioned out. This process helps prevent an infection and aids in the healing process. If an infection is sealed into the coelomic cavity the outcome could be catastrophic.

The incision made in the tissue lining the cavity is sutured next, using the same type of suture material as the bladder. The muscular attachments to the cut piece of shell will gradually reestablish themselves to the underside of the cut piece.

While all of this was going on the piece of shell that was removed at the beginning of the surgery was kept moist by wrapping it with sterile gauze soaked with saline. Doctor R is removing the gauze before putting the cut piece of shell back in place.

When the shell is back in place bone wax is used to help seal the edges

Now the fun of putting the shell back together begins. The previously removed piece of shell is put back into position and a piece of fiberglass is measured and cut so that it just covers the cut piece of shell.

A special quick drying epoxy is poured on the shell. Once this epoxy hardens it can not be removed or reshaped, so we have to move fast. The first layer of epoxy is put directly on the shell.  When it gets tacky we are ready for the next step.

Before this first layer dries the fiberglass is placed on the shell and another layer of epoxy is layered.

When completed this is what the final result looks like

The epoxy becomes firm within a few minutes. During this time it is important that the tortoise does not wake up or breathe deeply because the pressure in the lungs will push the patch out. Cellophane is put over the patch for cleanliness.

Here is our friend just waking up from anesthesia. We remove the breathing tube when she is breathing on her own adequately.

At this point we will give her a pain injection and place her in a special room that maintains a temperature of 85 degrees. She will stay in the hospital for a few days until she is eating and active.

We have a short video of the beating heart of a tortoise during this procedure. You can see the heart beating during the surgery because reptiles do not have a diaphragm, the muscle that separates the chest from the abdomen. Since there is no abdomen, technically it is called the coelomic cavity.

Prevention

Keep your tortoise well hydrated with acess to drinking water and soaking as previously described. Feed mimimal amounts of green leafy vegetables and large amounts of grass. Do not supplememt with excess calcium or Vitamin D3 if your tortoise has access to direct sunshine as seen in our western and souther states. It is theorized that an active tortoise foraging in a large area will excrete more urates when it urinates. Keeping it in a small area can inhibit its activity and potentially lose this advantage when exercising.

A yearly exam (palpating for bladder stones), blood panel, and radiograph, goes a long way to detecting a stone early. If small enough these stones might be amenable to being flushed out or removed by a pre-femoral approach, which is obviously much easier on your tortoise than cutting the shell.