Sometimes large pieces of skull bone are removed to temporarily relieve intracranial hypertension, or during debridement of open cranial injuries, or to treat certain skull fractures and cranial osteomyelitis, which often cause cranial defects in the child. When the cranial defect occurs in the temporal and inferior occipital regions, which are sheltered by thick muscles, it does not usually cause adverse reactions; however, if it occurs in other parts of the skull cap, it will cause the following two extreme conditions
1. Brain bulge. This often occurs after debridement or osteotomy decompression. The bulging mass sometimes contains degenerated brain tissue, large amounts of cerebrospinal fluid, and enlarged, deformed, and displaced ventricles toward the skull defect. The local scalp also thins as it bulges. After this condition develops, it cannot be cured by repeated local punctures to release fluid. The dural and cranial defects should be repaired as much as possible.
2. Cranial defect syndrome. This condition also often occurs after debridement or osteotomy decompression surgery and open craniocerebral injury debridement surgery, a few occur after cranial bone marrow surgery, two phenomena can often be seen, one may be related to the original occurrence of serious brain parenchymal damage, so a very obvious local depression, some patients feel abnormal scalp pain at the edge of the depression, and even refuse to touch the doctor to check; the other may The original brain injury is mild and the local depression is not obvious. However, because the skull defect is too large, the physiologically necessary intracranial pressure cannot be maintained with proper stability; therefore, the local area bulges up when the head is in low position, and collapses on the contrary. After strenuous physical activity, the person will feel that the intracranial turbulence is long, the brain tissue is swaying inside the skull, the blood supply to the brain is fluctuating, and the adhesions between the scalp and tissues are stretched, thus causing headache, dizziness, and inability to sustain activities, and even nausea and vomiting.
The principle of treatment for these two extreme cases is to repair the cranial defect as soon as possible. In addition to this, the repair of cranial defects has several effects as follows.
①Brain protection effect. Generally speaking, cranial defects with a diameter of more than 3 cm are repaired if they are not located under the temporal or occipital muscles.
②Cosmetic effect, cranial defects in the frontal orbital area should be repaired for cosmetic appearance even if they are small in extent and asymptomatic.
(③) Prevention and treatment of epilepsy, whether skull repair can improve the presence of epilepsy.
④May have a preventive effect on brain atrophy.
For skull defects left after craniocerebral trauma or hypertensive cerebral hemorrhage debridement and decompression, previous experience suggests that it is appropriate to repair the defect 3-6 months after surgery to reduce the rate of postoperative infection and to give the patient a relatively long recovery period.
However, early repair of cranial defects (4-6 weeks) has the following advantages.
(1) Restoring the original shape of the cranial cavity as soon as possible, which is conducive to the restoration of normal intracranial pressure and physiological brain function.
(2) Preventing brain tissue displacement from pulling and distorting cerebral vessels, causing brain tissue ischemia and necrosis, thus reducing further aggravation of cerebral nerve dysfunction in the cerebrovascular blood supply area.
(3) Preventing cerebrospinal fluid circulation disorders caused by brain tissue displacement, which may induce subdural fluid accumulation on the contralateral side of the defect or in the longitudinal fissure.
(4) Restoring the skull shape as early as possible can not only relieve or eliminate the headache, dizziness, memory loss and other complications caused by the skull defect, but also relieve the patient’s anxiety or fear in time.
(5) For those who complete cranial repair and ventriculo-abdominal shunt at the same time, it can reduce the risk and incidence of surgical injury, complications and sequelae caused by the increased number of operations and anesthesia, as well as reduce the mental and economic burden of patients and their families.
(6) The earlier the surgery is performed, the smaller the extent of scar formation at the incision and the lighter the adhesions are, the easier it is to separate them during surgery, thus achieving the purpose of less bleeding, shorter operation time and lower cost.
(7) Early skull defect repair is beneficial to the one-time treatment of traffic accidents. Traffic accidents not only bring physical and mental injuries to patients, but also bring many troubles to both families, and generally involve more energy due to the difficulty of reaching a consensus agreement on treatment costs. If two surgeries are completed in one hospitalization, it has positive significance for both parties of the accident.
(8) If the bone flap removed during debridement and decompression is preserved intact under the abdomen and used as material for early repair, it is very important to eliminate rejection and reduce the cost of surgery, but unfortunately, it was not tried in our group.
However, not all patients with cranial defects are suitable for early surgery, and the selection of their surgical indications and contraindications should be strictly followed.
(1) Skull defect area >3 cm.
(2) Clear consciousness and no complications.
(3) Those with clear consciousness and certain complications, but not affecting the operation, such as combined hemiplegia and aphasia.
(4) Patients with early combined hydrocephalus, if possible, should be completed at the same time as ventriculo-abdominal shunt, if conditions permit.
(5) Early surgery is not recommended for open injuries or cranial defects left by heavily contaminated comminuted fractures, although the intraoperative management is very thorough.
(6) Poor incision healing or infection is an absolute contraindication.
(7) Patients with coma, tracheotomy, pulmonary and gastrointestinal complications should wait until their condition is stabilized before deciding whether to perform surgery.
The treatment of cranial defects is to perform cranioplasty, but the timing, method and materials used as well as the indications and contraindications for surgery must be carefully considered, especially the purpose of the patient’s request to repair the cranial defect and what problems he/she wants to solve. This is because the outcome of cranioplasty alone is unpredictable for the treatment of functional symptoms, mental disorders and traumatic epilepsy manifestations after traumatic brain injury.
Repair materials for cranioplasty of cranial defects.
The ideal cranial repair material must have the following
(1) Easy shaping and fixation.
(2) Low tissue reaction and non-toxicity.
(3) chemically stable, not corroded, absorbed or aged in the tissue.
(4) able to transmit X-rays
(5) Non-heat transfer and non-conductive.
(6) light in texture and sufficient mechanical strength. The cranial bone repair materials currently used can be summarized into four types.
1, autologous bone graft: generally applied to the iliac bone, rib bone and cranial plate, etc., because this kind of autologous bone without foreign body stimulation, small reaction, good healing process after surgery, and a certain curvature, in line with the physiological requirements, but its disadvantage is to increase a surgery, shaping is not ideal, the appearance is not good.
2, allogeneic bone grafting: often using bone from other people or cadavers stored in bone banks, foreign body stimulation is slight, the healing process is still good, but because of the storage relationship, can increase the chance of infection. The above two methods are rarely applied [MedEducation.com]. After 6 months after transplantation are graft bone is absorbed, and gradually replaced by new bone, so some people believe that the substitute is preferable
3, allogeneic bone graft: that is, the use of animal bones, animal horns, ivory, etc., but such materials often due to absorption or infection and incur failure. Therefore, it has been abandoned.
4, foreign body graft: foreign body graft can be divided into two categories, namely, metal foreign body and non-metal foreign body, commonly used metals are tantalum, titanium (titanium) alloy plate or stainless steel wire mesh, both domestic and foreign have been used, its convenient shaping, light tissue reaction, good appearance, is a good material for cranial bone repair. However, metal materials have thermal conductivity, and patients are not suitable to work under the sunlight, and there are also conductive and impervious to X-ray, which hinders the patient’s future examination. Non-metallic materials: commonly used polymethylmethacrylate (i.e., plexiglass), is a commonly used material, characterized by light and toughness, not easy to break, chemically stable, not easy to corrode, non-toxic, between -183 ° C to +60 ° C mechanical strength is not reduced, but its impact resistance and tensile strength and improve, between 70 ~ 90 ° C variable soft, easy to shape, and after cooling accurately maintain the plastic shape. After cooling, it maintains the exact shape of the plastic, is a poor conductor of electric heat, can pass through X-rays, facilitates postoperative examination, simple molding procedures, easy to take materials, the size and shape of the defect is not limited in the selection, and the postoperative tissue reaction is light. Silicone rubber and ceramic materials are ideal new substitutes for cranial defect repair, which are made into cranial shape at the time of factory production and can be cut according to the shape and size of the defect site.