Corticotomy is surgical procedure where the cortex of the bone is cut to stimulate bone formation.
Bones consist of an outer cortex and an inner medulla. The cortex is the hard mineralized part of the bone that gives the bone its rigidity. The medulla is the soft inner part that contains the bone marrow. This bone marrow produces blood cells. As the person grows older the bone marrow gets replaced by fatty tissue in many bones.
The bone is surrounded on the outer side by a membrane called the periosteum. The periosteum consists of two layers, the outer fibrous tissue, and an inner osteogenic layer that contributes to the formation of bone cells.
During the surgical technique of corticotomy, the cortex is deliberately fractured. The fracture acts as a stimulus to promote new bone formation. The technique has been adopted in orthodontics and in orthopedics for certain conditions where quick bone growth is required.
Corticotomy is performed as a dental or an orthopedic procedure:
In the procedure referred to as distraction osteogenesis, corticotomy is performed and then a gradual traction is applied to the parts of the bone that have been partially separated by corticotomy. The corticotomy stimulates bone growth in between the fractured parts and thereby contributes in increasing the length of the bone.
For the dental procedure, the orthodontist will first examine your teeth and plan out the type of orthodontic treatment that you will require. An x-ray will be obtained to confirm the findings through a quick and painless procedure where you will be asked to bite on a mouthpiece. The orthodontist and the dental surgeon who will be performing the corticotomy will discuss the best way forward. You will be asked to stop any blood thinners that you may be taking before the procedure.
During the Procedure
After the Procedure
After the procedure, you may be prescribed an antibiotic and painkillers. You can eat soft foods till you are comfortable enough to eat more solid food.
Following the corticotomy, the dentist has a very short window period during which the entire orthodontic procedure should be completed to get the maximal benefits of the corticotomy. The orthodontic procedure should be started within two weeks of the corticotomy. Since the teeth move faster, the orthodontic adjustments should be done at intervals of less than two weeks. The procedure is usually completed in 6 months.
For the orthopedic procedure, the surgeon will ask you to undergo tests like a CT scan or an MRI. During these procedures, you will have to lie down on a table. During a CT scan, a scanner will pass over the part of the body to be scanned, while for an MRI, the table will move into a tubular machine. X-ray procedures like teloengenogram and orthoroentgenogram, and scanogram using CT scan or x-ray are used to measure the limb-length discrepancy.
Type of Anesthesia – The limb lengthening procedure is done under general anesthesia. You will be asleep during the procedure and will not be aware of what is going on.
Pre-operative Check-up – Routine tests as indicated above are ordered a few days before the surgery. These include:
In older patients, a detailed assessment of the heart maybe required
Admission is required a day or two before the surgery. You will be advised to stop taking aspirin or blood thinners a few days before the procedure.
Fasting before surgery - Overnight fasting is required and occasionally intravenous fluid maybe required to keep you well hydrated. Sedation is sometimes required for good overnight sleep before the surgery.
Shift from the ward or room to the waiting area in the operating room - An hour or two before the surgery, you will be shifted to the operating room waiting area on a trolley.
Once the surgical room is ready, you will be shifted to the operating room.
Shift to the Operating room - The ambience in the operating room can sometimes be very daunting and a small amount of sedation can help overcome your anxiety. From the trolley, you will be shifted on to the operating table.
Anesthesia before surgery - The anesthetist will inject drugs through an intravenous line and make you inhale some gases through a mask that will put you in deep sleep.. Once you are in deep sleep, a tube will be inserted into your mouth and windpipe to administer the anesthesia gases to overcome pain and keep you comfortable.
During the Procedure
After the Limb lengthening Procedure
Waking up from Anesthesia – Once the surgery is over you will wake up and the tube down the wind pipe will be removed. You will be asked to open your eyes before the tube is removed. You will be sedated and the voice of the anesthetist may be faint. Once the tube is out, you may have cough and sometimes nausea.
There may be a tube going into the stomach called a nasogastric or Ryle’s tube to keep it empty. There will also be an intravenous line. You will remain on oxygen. Once fully awake, you will be shifted on the trolley and taken to the recovery room. The fixator will be attached to your operated limb.
Recovery room – In the recovery room, a nurse will monitor your vitals and observe you for an hour or two before shifting you to the room or a ward.
Painkillers may be prescribed depending on the extent of the pain.
Post-operative recovery – You will be allowed to walk soon after the procedure, depending on your comfort. In fact, early movement after the procedure is encouraged. Following the surgery, the fixator will be regularly adjusted so that there is distraction at the corticotomy site that stimulates new bone formation and thereby lengthens the bone. It may take a few months for optimal results, and may be inconvenient due to the bulkiness of the fixator.
Physical therapy is also necessary to maintain the function of all the muscles and joints. Once the new bone appears strong enough, the fixator is removed.
Complications of corticotomy following the dental procedure are usually minimal. They may include:
Complications following the limb lengthening procedure may include:
Pretty accurate run down, I had corticotomy performed on my left foot, I fell and earned myself lisfrac injury fracturing the second and forth metatarsals. I was fitted with an external fixator for 6 months, the procedure described in this article is more or less of what I experienced in the ultra capable hands of my surgeons and anesthesic doctor, only that I was awake the whole four and a half hours in theater.